Pilot Award Program

Educated Osteoblasts in Bone Metastatic Prostate Cancer

The mechanisms that cause prostate cancer (PCa) cells to re-awaken from a growth suppressed state for years are unknown. Given the large number of patients who have reoccurrence and progress to macrometastases and the fact that treatment options are limited and mainly palliative, there is an urgent clinical need to understand mechanisms that drive PCa growth suppression and re-awakening in bone to eliminate the cancer cells and prevent recurrence. 

Recent reports have pointed to factors in both the hematopoietic and endosteal bone niche as keys to regulating bone disseminated tumor cell growth and progression to metastasis. Yet, there are significant gaps in knowledge about which bone cells are involved and the exact mechanisms that facilitate latent PCa cell re-awakening and progression to metastasis. The Bussard lab addresses that gap by being the first laboratory to identify multiple subsets of osteoblasts in the bone-tumor niche that differentially regulate PCa progression.

Preservation of Erectile Function with Early Postoperative Application of Low-Intensity Shockwave Therapy after Nerve-Sparing Radical Prostatectomy

The Preservation of Erectile Function with Early Postoperative Application of Low-Intensity Shockwave Therapy (LiSWT) after Nerve-Sparing Radical Prostatectomy (NS-RP) is a pilot trial exploring the outcomes of a noninvasive treatment for men following prostate cancer surgery. Erectile dysfunction (ED) is a common complication of the prostatectomy procedure, reported broadly anywhere from 14 to 90% depending on circumstance. In recent years, LiSWT therapy has come to the forefront in improving function in men with ED, along with treating a wide range of musculoskeletal disorders and motor neuron damage. This trial will utilize the UroGold100 device, an electrohydraulic unfocused shockwave delivery system that delivers painless electrotherapy for increased blood flow, promoting tissue repair. The study team will leverage the NSRP surgical population of Jefferson’s Department of Urology and the resources of the Center for Men’s Health to determine the effect of LiSWT therapy on penile function following NS-RP.

Men ages 18 to 80 who meet the inclusion criteria will be recruited to participate in the study prior to the NS-RP pre-operation workup. These men will undergo two six-week courses of LiSWT in addition to their standard post-surgical care. The primary outcome of this study is to determine if there is improved penile function measured at six-months post-surgery and serially in the year following surgery. 

Secondary outcomes include Duplex Doppler Ultrasound penile blood flow parameters at six-months post-surgery and additional surveys of sexual function. The trial will produce quality, generalizable data that will support future external funding applications and lay the groundwork for larger clinical trials using this treatment approach. This Phase I clinical trial started accrual of patients in July 2023 and is estimated to enroll 30 patients with completion by April 2025.

Unveiling the Role of AR-V7 in STEAP1 Regulation and its Implications for Enhancing Prostate Cancer Treatment

Prostate cancer (PCa) alone accounts for 29% of cancer diagnoses in men in the United States as of 2024. Androgen receptor (AR) is the primary oncogenic driver for PCa, with androgen blockade therapy serving as the cornerstone therapeutic approach for hormone-sensitive, early-stage disease. However, over time, tumor cells adapt to low androgen conditions, resulting in the development of metastatic castrate- resistant disease (mCRPC), which lacks responsiveness to androgen blockade. Proteomic analysis from mCRPC patient samples revealed the emergence of a constitutively active, or always on, variant of AR denoted AR-V7. AR-V7 appears after the transition to mCRPC, fueling disease aggressiveness and worsening patient outcomes, necessitating the development of novel therapeutic strategies. Despite recent therapeutic advances, more than half of men initially diagnosed with localized disease are currently living with metastatic PCa. 

Our research focuses on understanding the oncogenic role of Six Transmembrane Epithelial Antigen of the Prostate (STEAP1), a cell surface protein that exhibits increased expression in malignant tissue. STEAP1 is regulated by androgens. Analysis of clinical samples revealed that STEAP1 is part of a unique subset of genes associated with AR-V7 expression. Cell surface expression makes STEAP1 an attractive target for immune-based treatments such as CAR T-cells and bi-specific T cell engagers (BiTEs). 

BiTEs link cancer cells with T cells, boosting the immune response directly within the tumor. The first clinical trial of a STEAP1-targeted BiTE, known as Xaluritamig (AMG509), showed promising results with nearly half of the patients experiencing a significant reduction in prostate-specific antigen (PSA) serum levels. STEAP1-targeted CAR T- cells have been effective in reducing tumor size and improving survival in mice, although some tumors eventually lost STEAP1 expression, impacting treatment efficacy. Our preliminary data, supported by existing literature, suggest that STEAP1 regulation is influenced by AR-V7 activity, and that this regulatory event is altered in low androgen conditions. This suggests a unique regulatory pathway that diverges with advanced disease, yet the dynamics of AR-V7’s influence on STEAP1 remains insufficiently explored.

There are two major goals for these studies. First, we will determine how the androgen signaling network influences STEAP1 expression at different stages of disease progression. Second, we will examine the therapeutic potential of combinatorial treatment strategies and identify additional targetable pathways, paving the way for future research. Initially focusing on established PCa treatments, we will combine pharmacological hormone modulation and precise genetic modifications to independently manipulate AR and AR-V7 in cell models at different disease stages. Subsequent analysis will employ flow cytometry and surface antigen-binding assays to directly quantitate STEAP1 surface enrichment. These studies will establish the contribution of AR-V7, providing crucial insight into fundamental PCa biology, and define the impact on cell surface presentation. The clinical potential of combining hormone modulation and STEAP1-directed therapy will be evaluated by in vitro T cell cytotoxicity assays. Understanding differential impacts of combining STEAP1-targeted immunotherapy with existing treatments in various disease states will inform optimal points for therapeutic intervention and influence clinical decision-making.  

Advanced genetic screening techniques will be employed to identify additional regulators and broaden the arsenal of targetable pathways that could be leveraged to enhance the effectiveness of STEAP1 therapies. Using an integrated approach consisting of CRISPR-Cas9 technology, flow cytometry, and next- generation sequencing, we will investigate around 19,000 genes and determine their impact on STEAP1 cell surface expression. These findings will guide future research and will help us pinpoint the exact mechanisms that control STEAP1's presence on cancer cells. With this knowledge, we will design comprehensive screening panels to find drugs that target these mechanisms to create powerful combination treatments, paving the way for more effective and personalized treatments for PCa.

Our research will clarify the dependence of AR and AR-V7 on STEAP1 regulation and will uncover key insights into how treatment strategies should evolve with disease progression. The data generated from our studies will not only support future research and collaborations, but also contribute significantly to the scientific community's understanding of PCa biology and unveil mysteries surrounding AR-V7 signaling. We are optimistic that our findings will lead to a deeper understanding of PCa biology and provide invaluable insight to enhance therapeutic strategies, ultimately guiding clinical treatment decisions for improving patient outcomes.

Validation of Sigma1 as a Novel Multifunctional Drug Target in Patient-Derived Prostate Tumor Models of Therapeutic Resistance

*Team Member: Elahe Mostaghel, MD, PhD

First line therapy of prostate cancer (PCa) involves suppression of androgen receptor (AR) activity by castration or androgen deprivation therapy (ADT). However, patients inevitably progress to lethal castration-resistant prostate cancer (CRPC). CRPC remains incurable. There is an urgent need for new drugs, targets, and approaches to preventing and treating CRPC. 

Sigma1 is a unique protein that is abnormally expressed in PCa cells and plays a critical role in supporting the enhanced metabolism associated with tumor growth. Importantly, Sigma1 is a druggable target and has multiple interfaces with AR-mediated cellular processes. Sigma1 targeting drugs block AR-dependent growth, as well as other aspects of metabolism in cancer cells. Therefore, Sigma1 drugs could effectively block multiple pathways by which PCa cells can adapt and become resistant to current standard of care therapeutic agents. We have discovered and are developing a novel series of drug-like Sigma1 inhibitor (Sigma1i) compounds. 

The objective of this project is to evaluate the anti-tumor activities of Sigma1i in heterogeneous and clinically relevant PCa patient-derived xenograft (PDX) tumor models. These PDX tumors have several clinically relevant features that more closely represent a patient’s prostate tumor than traditional PCa cell lines. As molecular heterogeneity is likely to be greater between different PDX models than within an individual model, evaluating multiple PDX models provides a greater ‘dynamic range’ of response.

These studies will model a more relevant stromal environment and should more accurately reflect potential clinical responses. We propose a completely new approach to treating patients with lethal CRPC. Sigma1 is a novel target and our Sigma1 inhibitors a novel drug class for PCa. This work will provide key target validation studies to accelerate the path to investigational new drug filing. The overarching challenges addressed in this proposal are to better define the biology of lethal PCa, and to develop a novel treatment approach that suppresses a critical mechanism that drives PCa malignancy, thereby improving outcomes for men with lethal prostate cancer. 

Organization of Whole Mount Prostate Cancer Cohort from African American and European American Men at Thomas Jefferson University

*Team Member: Charalambos Solomides, MD

Carcinoma of the prostate is known to present at a higher stage and behaves more aggressively in American men of African descent (AA) compared to Caucasian American men (CA). Yet all available nomograms for prognostication and management are based on data obtained from CA. Our preliminary findings obtained from review of a single standard sized slide from 100 AA and 100 CA patients have demonstrated molecular genetic difference between prostate cancer in comparison with CA. 

Additionally, this data suggests that immunologic differences (which represent the body’s reaction to cancer) also exist between the two groups. These initial results need to be tested on a larger data base in order to gain deeper understanding of events that drive development of aggressive prostate cancer in AA men. 

In this project, we are developing a stage-matched prostate cancer cohort derived from AA and CA who were operated at Thomas Jefferson University Hospital (TJUH) with a minimum follow-up of 10 or more years. This cohort is unique not only for the long follow-up but also because prostatectomy cases from TJUH were processed to generate whole mount slides.

Inflammometabolic Reprogramming in Prostate Cancer

Prostate cancer is the second-leading cause of cancer death in males in the United States. Metabolic, as well as inflammatory reprogramming, are well-established drivers of cancer aggressiveness in the prostate cancer micro- and macro-environment. Metabolism is the area of biology that studies how cells obtain and utilize energy-containing molecules. Glucose and its byproduct, lactate, are among the most common metabolites generated in tumors. Inflammation is the body’s response to an irritant, such as an injury, infection, or other danger and it’s known to be dysregulated in cancers, in general, and prostate cancer, in particular. 

Cancer immunotherapies are treatments that stimulate the immune system to control cancer growth. Large efforts have been devoted to studying the effects of immunotherapies on prostate cancer cells, but little is known about how modulating the metabolism and the inflammatory profile of immune and non-immune cells may affect anti-cancer immune responses in prostate cancer. Our overall hypothesis is that metabolic and inflammatory changes in cancer, including an increase in lactate production and utilization, as well as interleukin-6, causes anticancer immune impairment with progression of prostate cancer. 

In Aim 1, we will elucidate the mechanism whereby high lactate production and release affects anticancer immune responses and tumor growth in prostate cancer. In Aim 2, we will determine if blocking interleukin-6, which induces lactate production in the tumor environment, will improve anticancer immune responses and reduce tumor growth. In Aim 3, we will determine if changing the metabolism of cytotoxic T cells from lactate production to lactate utilization will improve anticancer immune function and reduce tumor growth in prostate cancer. Cytotoxic T cells have the ability to kill cancer cells. Understanding the metabolic and inflammatory drivers of impaired anticancer immunity and tumor growth may provide opportunities to develop new treatments for prostate cancer.

Study of the Nucleoporin-Chk1 axis in lethal prostate cancer

Despite recent advances in the treatment of lethal prostate cancer (LPC), this disease remains a clinical challenge due to its inevitable treatment failure and devastating clinical outcome, with over 33,000 men deaths estimated in the United States for 2021. Currently the mechanisms of PCa tumor progression to a lethal therapy refractory disease stage are not completely understood. Thus, elucidating novel targetable molecules and pathways contributing to PCa lethality is a major challenge that needs to be tackled.

In this proposal, we take a novel conceptual approach to study castration and chemotherapy resistant PCa by focusing on the contribution of the Nuclear Pore Complex (NPC) to enhance DNA replication and damage checkpoint functions in LPC. Nuclear Pores are protein complexes embedded within the nuclear envelope (NE) that regulate a wide range of critical cellular functions such as nucleo-cytoplasmic transport, intracellular signaling, transcription, and genome integrity. Nucleoporins (Nups), the NPC components, have been described to contribute to tumor formation and progression in several cancer types. However, the specific Nups and Nupbased mechanisms contributing to cancer remain ill-defined.

Our lab was the first to discover the key role of upregulated Nup POM121 in promoting aggressiveness of PCa by enhancing transport of AR, MYC, GATA2 and E2F1 into the nucleus (Cell, 2018). Thus, our work gave a strong premise to continue interrogating the multifaceted roles of Nups in PCa. Our new preliminary studies indicate Nups can modulate gene expression of G2/M and DNA damage genes in LPC and in addition, they may also modulate checkpoint response by direct interaction at the pore, where DNA repair and replication has been proposed to take place but not formally proved. Since genome aberrations are known to increase as the function of PCa disease progression, our findings led us to hypothesize that NPCs via specific Nups, enhance genome integrity responses and survival of LPC cells.

We will test this hypothesis using in in vitro and in vivo experimental LPC models and applying epigenomic, high-resolution microcopy and preclinical approaches. Upon completion, the proposed research has the potential to identify novel molecular mechanisms of lethal PCa aggressiveness and relevant actionable molecules that may be used to develop novel biomarkers and therapeutic approaches to improve the clinical outcome of this devastating disease.

Targeting STEAP1 Antigen Receptors in Voided Urine to Detect Prostate Cancer and to Determine the Severity of the Disease

*Team Member: Patrick T. Gomella, MD

Prostate cancer (PCa) is a heterogeneous disease in its molecular, morphological, and even in its clinical presentations. It is the most common non-cutaneous cancer diagnosed, with approximately one in every seven men over the age of 60 being diagnosed with PCa. The American Chemical Society estimated that in 2023, in the U.S. alone, there were 288,300 new cases of PCa and 34,700 deaths attributed to PCa.

PCa treatment recommendations depend on many factors. However, they are heavily influenced by the aggressiveness of PCa, as determined by the assigned Gleason Score or Grade Group (GG), combined with clinical factors that determine the patient risk classification. At the present time, despite improved imaging modalities, determination of the Gleason score or GG is only possible by performing a prostate biopsy to allow histopathologic evaluation. Due to the invasive nature of the procedure, it exposes the patient to risks, such as infection and bleeding. Prostate biopsy is also affected by sampling error, which may lead to delayed diagnosis and delayed definitive treatment. Increasing urologist and patient access to a simple, reliable, noninvasive, and lower-risk technique to diagnose PCa and determine its aggressiveness at the same time may potentially minimize the need for needle biopsy. 

The Six Transmembrane Epithelial Antigen of the Prostate (STEAP1) protein are over-expressed in PCa, amongst several other kinds of tumors. In normal epithelial cells and tissues, STEAP1 expressions are restricted. A body of literature strongly indicates that the greater the STEAP1 expression, the higher the PCa severity and the poorer the patient prognosis. 

We propose to determine STEAP1 expression quantitatively by two robust techniques using PCa cells shed in voided urine. Firstly, by performing immunohistochemistry, followed by optical imaging of malignant cells using a Zeiss Axio observer fluorescent microscope specifically designed to quantify the intensity of STEAP1 protein, and secondly by performing reverse transcription polymerase chain reaction (RT-PCR), a laboratory technique that measures the amount of a specific RNA. Data from both assays will be pairwise analyzed statistically and compared with those of the control cohort and correlated to the PCa pathologic GG diagnosis (GG1-5).

Direct and Combinatorial Anti-tumor Effects of CX3CR1 Antagonists in Prostate Cancer

*Team Member: David Sykes, MD, PhD

Most patients presenting with localized prostate adenocarcinoma are definitively cured by radical prostatectomy and/or radiation therapy. However, approximately 20% of patients will eventually present with distant recurrences, which target the skeleton in more than 90% of cases. Metastatic prostate cancer is treated by hormone-deprivation and/or inhibitors of androgen receptor function and these approaches are initially effective in decelerating or arresting disease progression. Unfortunately, a significant fraction of these patients will eventually develop castration-resistant prostate cancer (CRPC), which is currently incurable.

Therefore, innovative and more effective therapeutics aiming to achieve curative effects in advanced prostate cancer is an unmet clinical need. Two novel and promising therapeutic strategies are 1) targeting the cancer cells that are uniquely capable of initiating metastases after disseminating from the primary tumor, and 2) utilizing approaches such as checkpoint inhibitors blockade to promote the elimination of cancer cells by immune cells with cytotoxic activity.

Previous studies from the Fatatis lab (Drexel University) and Sykes lab (Harvard University) strongly suggest that chemokine receptor CX3CR1 represents a viable target to pursue both therapeutic strategies described above.

The Fatatis lab has demonstrated that the chemokine receptor CX3CR1 is associated with tumor-initiating features in prostate cancer cells and has developed FX-68, a small-molecule CX3CR1 antagonist. When used in murine models of metastatic disease, FX-68 impaired progression, caused a massive reduction in tumor burden, and induced complete regression of some tumors. The Sykes lab used single cell-RNA sequencing on human samples of advanced prostate cancer to identify several subpopulations of myeloid cells populating the metastatic niche and correlated with cytotoxic T lymphocyte exhaustion. Notably, abolishing the interaction between the immunosuppressive myeloid cells and T lymphocytes in a syngeneic animal model of metastatic prostate cancer prolonged overall survival. Furthermore, CX3CR1 was detectable across the different myeloid cells including the tumor inflammatory monocytes (TIM) and tumor-associated macrophages (TAM). Consistently, the Fatatis lab has shown that FX-68 treatment impairs migration of TAMs into skeletal tumors in mice.

Based on these findings, this proposal will use a combination of in vitro approaches and animal models of metastatic prostate cancer to ascertain whether FX-68 – by blocking CX3CR1 – a) exerts a direct anti-tumor effect by functionally impairing the cancer cell population specifically responsible for tumor-initiation, and b) prevents myeloid cells from suppressing the cytotoxic activity in T lymphocytes, thus reinstating the response to immunotherapies.

Genomic Differences and Clinical Implications of DNA Methylomes between Single and Clustered Circulating Tumor Cells in Patients with Metastatic Castration Resistant Prostate Cancer

*Team Members: Nathan R. Handley, MD and Hushan Yang, PhD

The goal of this study is to compare methylome features between single and clustered circulating tumor cells (CTCs) by conducting whole-genome bisulfite sequencing (WGBS) and evaluating their associations with clinical outcomes in patients with metastatic castration-resistant prostate cancer (mCRPC). The expression levels of the androgen receptor and prostein on CTCs will be examined and their prognostic value in mCRPC will be evaluated. We already established a comprehensive pipeline including whole genome amplification, next-generation sequencing, bioinformatics analyses, and statistical analyses of WGBS data. The team is currently working on sequencing and data analysis. 

We identified an association of positive expression of prostein on CTCs with unfavorable survival in mCRPC metabolic activity. We have submitted our paper to a peer-reviewed journal suggesting that prostein expression on CTCs may serve as a novel prognostic marker in mCRPC patients. 

Microdosimetry for Prostate Cancer Radiotheranostics

Our project proposes using advanced radiation measurement and imaging technology coupled with artificial intelligence (AI) and 3D printing methods to establish the Sidney Kimmel Comprehensive Cancer Center as a Center of Excellence for Radiopharmaceutical Microdosimetry. Radiopharmaceutical therapy (RPT) has been shown to improve survival for prostate cancer patients with metastatic disease. The challenge with RPT is that the characteristics of the radiation dose distribution, known as dosimetry, are severely underdeveloped and poorly understood. 

Future RPT developments seek to target cancer cells more precisely and therefore require more precise understanding of dosimetry, known as microdosimetry. The proposed project will test the central hypothesis that a novel microdosimetry system can measure absorbed dose from alpha-emitting radionuclides with 50 µm spatial resolution and dose accuracy within 15% through three specific aims. 

Aims 1 and 2 will evaluate the two primary components of the system’s spatial resolution: the intrinsic resolution of the novel camera (Aim 1) and the spatial accuracy of an AI image-stacking algorithm (Aim 2). Aim 3 will evaluate the dosimetric accuracy of the microdosimetry system. Our project will initiate and benchmark an RPT microdosimetry program at SKCCC. An RPT microdosimetry program will fill a critical need in the field that will be appealing for future National Cancer Institute funding to advance our understanding of radiobiology, enable personalized RPT treatments, and support novel drug development. 

Circulating tumor cell (CTC)-based patient derived-xenograft (PDX) and -organoid (ORG) model systems platform for the development of novel therapeutic approaches in lethal prostate cancer

*Team Members: Adam Ertel, PhD 

Once prostate cancer (PCa) progresses to an advanced metastatic therapeutic resistant stage, it becomes an incurable deadly disease. In order to accelerate the development of novel therapeutic strategies there is an imperious need to develop clinically significant PCa experimental models that recapitulate the molecular landscape of lethal disease. 

To date, these advanced lethal prostate cancer (LPC) models have been difficult to generate since tissue samples are rarely obtained once PCa patients develop metastatic disease. 

In order to address this limitation, our group has pioneered the use of circulating tumor cells (CTCs) to generate lethal PC patient derived xenograft (PDX) and organoid (ORG) models. In published and preliminary studies discussed in this proposal, we have demonstrated the feasibility of generating these models from CTCs. Most importantly, preliminary studies suggest that these models recapitulate key features of advanced PCa (i.e. neuroendocrine-like phenotype) supporting the need to continue expanding this disease platform to generate models that include the heterogeneous nature of LPC. Moreover, the disease models of this platform constitute “avatars” where the efficacy of novel compounds may be tested. Indeed, the generation of organoid models allow the in vitro efficacy assessment of novel therapeutic compounds in a quick and less costly manner. 

Based on these results we hypothesize that CTC-derived experimental models reproduce the molecular landscape of LPC and may contribute to develop much needed experimental models to boost the development of novel treatment modalities for this lethal disease. 

We will investigate this hypothesis by further developing and molecularly characterizing the clinical significance of the CTC model systems generated by comparing them to patient samples using state-of-the-art technologies (i.e., single cell genomic 10X GENOME profiling). In addition, the feasibility of these disease platforms to test the efficacy of novel compounds will be analyzed using a FDA approved compound library and small molecule compounds targeting specific molecules such as, GATA2. The development of this innovative disease platform will enable testing novel therapeutic approaches in a field of major clinical need and will further enhance the progress of novel predictive biomarkers and therapeutics into the clinic.

Genomic Multi-Omics Characterizations of Noninvasive Contributors to Racial Survival Disparity in a Multi-Ethnic Prostate Cancer Patient Cohort

*Team Member: Kevin Kayvan Zarrabi, MD

Kevin Kayvan Zarrabi, MD, and Hushan Yang, MD, PhD, are conducting multi-omics characterizations of circulating tumor cells (CTCs) to identify markers of prostate cancer prognosis and racial survival disparities. The systems have been tested with proof-of-concept data in prostate cancer (PCa) and other solid malignancies, such as breast cancer and head and neck cancer. This system will be applied to a large number of samples to obtain single CTCs and conduct downstream genomic sequencing and data analysis. 

This study has been approved by the Institutional Review Board (#21C.534). There have been 239 SKCCC patients with metastatic PCa who have been enrolled and 750 samples have been collected. The CTCs will be isolated using the DEPArray NxT system after CTC enrichment using the new Genesis system. DNA will be extracted from CTCs and paired white blood cells. 

Whole-exome and whole-genome sequencing will be performed, and a sequencing library will be conducted. A manuscript will be submitted with the data and findings obtained from the study. The research team also plans to submit a grant to obtain extramural support to continue this research.

Investigating Socioeconomic and Geographic Disparities in Multiparametric MRI Utilization for Prostate Cancer Diagnosis

Prostate cancer (PCa) is a leading cause of death and illness in men. Certain groups, especially African American men, experience worse outcomes compared to non-Hispanic Whites. African American men have a higher incidence of prostate cancer and are twice as likely to die from it. One of the key diagnostic tools for prostate cancer, Multiparametric Magnetic Resonance Imaging (mpMRI), has been shown to be particularly beneficial for African American men due to their higher likelihood of having certain types of tumors. Unfortunately, there are significant disparities in its use. Access to this procedure varies by race and ethnicity and understanding why is crucial for improving outcomes for all men.

This study aims to investigate what factors contribute to these disparities in mpMRI use. We will analyze data from a claims database, linking it to socioeconomic information from the areas where these patients reside. This will help us explore how factors such as where someone lives, their income, and the characteristics of the hospitals they visit impact whether or not they get mpMRI. Specifically, we will look at individual-level factors such as race, insurance status, and age, along with hospital characteristics and area-level factors like poverty rates and income levels as well as MRI availability.

By examining these three levels of influence (individual, hospital, and area), we hope to uncover how and why disparities in MRI use occur and what can be done to address them. For example, we will identify geographic areas with low MRI use and map these areas to help target future public health interventions and policy changes. This project will provide valuable insights that could inform future decisions about insurance coverage for prostate cancer diagnostic procedures and help reduce cancer-related health disparities.

Investigating Socioeconomic and Geographic Disparities in Multiparametric MRI Utilization for Prostate Cancer Diagnosis

Prostate cancer (PCa) is a leading cause of death and illness in men. Certain groups, especially African American men, experience worse outcomes compared to non-Hispanic Whites. African American men have a higher incidence of prostate cancer and are twice as likely to die from it. One of the key diagnostic tools for prostate cancer, Multiparametric Magnetic Resonance Imaging (mpMRI), has been shown to be particularly beneficial for African American men due to their higher likelihood of having certain types of tumors. Unfortunately, there are significant disparities in its use. Access to this procedure varies by race and ethnicity and understanding why is crucial for improving outcomes for all men.

This study aims to investigate what factors contribute to these disparities in mpMRI use. We will analyze data from a claims database, linking it to socioeconomic information from the areas where these patients reside. This will help us explore how factors such as where someone lives, their income, and the characteristics of the hospitals they visit impact whether or not they get mpMRI. Specifically, we will look at individual-level factors such as race, insurance status, and age, along with hospital characteristics and area-level factors like poverty rates and income levels as well as MRI availability.

By examining these three levels of influence (individual, hospital, and area), we hope to uncover how and why disparities in MRI use occur and what can be done to address them. For example, we will identify geographic areas with low MRI use and map these areas to help target future public health interventions and policy changes. This project will provide valuable insights that could inform future decisions about insurance coverage for prostate cancer diagnostic procedures and help reduce cancer-related health disparities.

Targeting the AlphaVBeta3 integrin in Neuroendocrine Prostate Cancer

*Team Members: Peter McCue, MD, Thenappan Chandrasekar, MD, and Fabio Quaglia, PhD

Our team is exploring novel research in the field of prostate cancer with the goal of developing an effective approach to cure an especially lethal and dangerous form of this cancer, termed neuroendocrine prostate cancer (NEPrCa). NEPrCa is a highly aggressive and metastatic subtype of prostate cancer that arises from a precursor form of this disease known as castrate-resistant prostate cancer. From a clinical perspective, NEPrCa is extremely difficult to treat and is associated with a very poor life expectancy of less than one year.

We have collected considerable data to support our hypothesis that the αVβ3 integrin is a promising therapeutic target for NEPrCa. We have recently shown that the αVβ3 integrin is highly expressed in human NEPrCa patient-derived xenografts, neuroendocrine (NE) bone metastasis, and mouse models of NEPrCa, while absent in prostate adenocarcinoma (ADPrCa). In the current Biome proposal, we hypothesize that αVβ3 supports NEPrCa progression and that αVβ3 in NE tumors could be utilized for efficient therapeutic targeting.

Through our proposed studies, we aim to develop a novel treatment strategy to combat this highly aggressive NEPrCa form of prostate cancer. Our application thus has the potential to make significant research advances in prostate cancer that will result in the development of new and effective tools to counteract this devastating disease.

VPAC Targeted Cu-67-TP3805 Theranostic for Prostate Cancer

*Team Members: Edouard Trabulsi, MD and Robert Den, MD

Great strides have been made in treating patients with castration-resistant and metastatic prostate cancer (PCa). Despite the novel approaches available for treating such PCa patients with chemo, immuno, radio or theranostic agents, the mortality of these patients has decreased only insignificantly. Recent advances in the theranostic agents such as Ra-223 dichloride (Xofigo), Ac-225-PSMA-617 and Lu-177-PSMA-617 have drawn considerable attention for the management of PCa patients with metastases. The most widely used amongst them is the Lu-177-PSMA-617 administered in three to 11 treatments each with 200 mCi, of which, can enhance patient survival up to 13.6 months.

Although encouraging, Lu-177-PSMA-617 induces such adverse events as xerostomia, anemia, renal toxicity, and fatigue. Furthermore, PSMA is expressed only on 80%-85% of the patients, making it unavailable for a large number of patients in need. These weaknesses compel physicians to pretreat salivary glands and kidneys and to perform a Ga-68-PSMA-11 PET scan on each patient to determine the patient eligibility for the Lu-177-PSMA-617 treatment. Additional weakness of this theranostic stems from the fact that Lu-177 contains up to 0.1% Lu-177m (t1/2= 161 days). Up to 75% of injected Lu-177, along with the longer-lived Lu-177m is eliminated through urine in 24 hours. The 161-day half-life of Lu-177m, in particular, creates a waste disposal problem specifically for those patients who are incontinent and wear diapers. Lu-177-PSMA-617 treatment is not approved by the FDA for use in the U.S.

This unmet need has prompted us to propose a novel approach in which we will target vasoactive intestinal peptides, VPAC receptors, for theranostic application of PCa. VPAC cell surface receptors that encode G protein are expressed in high density in all PCa types, irrespective of their heterogeneity. A VPAC receptor-specific agent Cu-64-TP3805 developed in our laboratory, permits us to PET image in humans, primary PCa, bone metastatic lesions, and malignant lymph nodes with high sensitivity. Added to these virtues are the fact that Cu-64-TP3805 has no uptake in salivary glands, bone marrow, renal medulla or urinary bladder. Copper-64 also has a sister radionuclide, a beta-emitting Copper-67, with such excellent theranostic qualities as the same tissue penetration range (6 mm) and the high linear transfer energy (LET) as that of Lu-177. It has a half-life of 2.6 days, is available commercially and has no longer-lived contaminant. Having the same chemical characteristics as those of Cu-64, Cu-67 will be easily incorporated into TP3805. With such appealing characteristics, we hypothesize that Cu-67-TP3805 will serve as an effective substitute to Lu-177-PSMA-617 to treat all PCa patients with minimal normal tissues toxicity, without having to perform pretreatment procedures and without inducing radioactive waste disposal issues.

Prior to FDA approval for large-scale studies in humans and an NIH RO1 application to support such and related studies, this investigation is designed to validate the hypothesis and to generate critical preclinical data that will be required to achieve both objectives. The data will be generated using an athymic nude, male mouse model bearing human PCa, grown by implanting human PCa cells, PC3. This androgen-independent cell line is derived from human bone metastases of human prostatic adenocarcinoma and is also known to metastasize in mouse bone. Furthermore, the feasibility of growing such tumors in nude, male mice and localizing them by targeting VPAC receptors using Cu-64-TP3805 has already been demonstrated in our laboratory.

The investigation will be performed in collaboration with urologists, medical oncologists, radiation oncologists, and pathologists at Sidney Kimmel Comprehensive Cancer Center, Dr. Alessandro Fatatis, who uses PC3 bone metastatic mouse models at Drexel University College of Medicine in Philadelphia, and a prominent radiation dosimetrist, Dr. George Sgouros, at Johns Hopkins University in Baltimore, Maryland.

AR-negative Cancer Cells and IL-1β in Skeletal Metastasis

Following local treatments such as surgery and/or radiation therapy, disease progression for prostate cancer patients is heralded by a return of the Prostate Specific Antigen (PSA) to detectable levels in plasma. The androgen receptor (AR) is widely implicated in driving the disease; therefore, the current strategy for these advanced stage patients is to deprive the AR of its major activator, the testosterone produced by the testes. This pharmacologic castration is effective in most patients, but approximately 10-20% of men will eventually develop castration-resistant disease (CRPC) within five years.

The treatments options available for CRPC include secondary hormonal therapies such as inhibitors of the AR such as Abiraterone and Enzalutamide. However, almost 90% of CRPC patients will have metastases at the time of CRPC diagnosis and, in general, the median survival for men with metastatic CRPC is approximately 15-36 months. Therefore, treatments for CRPC currently extend life expectancy in patients, but are not curative.

Recent evidence indicates that prolonged Androgen Deprivation Therapy (ADT) is associated with the emergence of malignant cellular phenotypes characterized by low or absent AR expression. We reported that skeletal metastases obtained from prostate cancer patients harbored ~30% of AR-negative tumor cells (ARNeg), suggesting that the majority of these lesions likely present a heterogenous AR-expression status. However, it is unclear whether ARNeg cancer cells contribute to metastatic growth.

Furthermore, we have reported that approximately 30% of tumor cells in skeletal metastases of CRPC patients lack AR. This feature makes these cells predictably impervious to androgen-deprivation and AR inhibitors. We have also revealed that cancer cells lacking AR (ARNeg) express high levels of Interleukin-1b (IL-1b), which is not detected in tumor cells that express AR (ARPos) and depend on androgens for their survival and growth. We have also found that blocking AR activity by removing testosterone or using enzalutamide also up-regulates IL-1b, and that this cytokine promotes metastatic progression in our pre-clinical models. This effect is exerted by altering the transcriptomic profile of the tumor-associated bone stroma, altering a set of genes that code for factors with a potential supportive role for the cancer cells.

Furthermore, while ARPos cancer cells are unable to generate disseminated tumors independently in animals, they survive and grow if cohabiting the bone with ARNeg cancer cells in AR-mixed tumors similar to those observed in patients. Strikingly, this is equally true in animals that are hormone-intact and hormone-deprived, suggesting that ARNeg also support ARPos cells in withstanding androgen deprivation.

Disruption of Lipid Metabolism and Stress Control Pathways that Enable Aggressive Prostate Cancer

*Team Members: Elahe Mostaghel, MD, PhD

Prostate cancer (PCa) cells are highly dependent on mechanisms that support the metabolism of lipids (fats and cholesterols) to fuel tumor growth and survival. Lipid droplets (LDs) are dynamic organelles that are made inside cancer cells to store and transport intracellular lipids for energy and lipid precursors to create cell membranes and to serve as signaling molecules. LDs function as hubs for metabolic processes and are important for cancer promoting metabolism. LDs also sequester toxic lipids and buffer cancer cells from reactive oxygen species (ROS), which enables PCa cells to adapt, survive, and proliferate in the often-harsh tumor environment. Thus, in cancer cells, LD metabolism is co-opted to serve as an adaptive response to metabolic and oxidative stress. 

LD accumulation is associated with increased cancer aggressiveness, therapy resistance, and poor clinical outcome in multiple cancers, including PCa. Important questions remain unanswered regarding how PCa cells retrieve and utilize lipids through LDs and how to target this for therapeutic benefit. The cellular machinery and underlying mechanisms by which these LD-associated effects occur in PCa remain poorly defined.

Sigma1 (gene name SIGMAR1) is a unique protein that is abnormally expressed in PCa cells and plays a critical role in supporting the increased lipid metabolism associated with tumor growth. Therefore, Sigma1 drugs could effectively block multiple pathways by which PCa cells become resistant to current standard of care therapeutic agents and progress to the lethal form of the disease. Here, we discovered that Sigma1 regulates LD metabolism in PCa cells. 

Sigma1 inhibition triggers lipophagy, an LD-selective form of autophagy, to prevent accumulation of LDs. This disrupts the interplay between LDs, autophagy, buffering of oxidative stress, and it results in the suppression of cell proliferation in vitro and tumor growth in vivo. Consistent with these experimental results, SIGMAR1 transcripts are strongly associated with lipid metabolism and reactive oxygen species pathways in prostate tumors. Altogether, these data reveal a novel, pharmacologically responsive role for Sigma1 in regulating the lipid metabolism and oxidative stress response mechanisms required by the oncogenic metabolic programs that drive PCa proliferation.

Study of the Nucleoporin-Chk1 axis in lethal prostate cancer

Despite recent advances in the treatment of lethal prostate cancer (LPC), this disease remains a clinical challenge due to its inevitable treatment failure and devastating clinical outcome, with an estimated 31,000 men dying from LPC in the United States in 2019. The mechanisms of prostate cancer (PCa) tumor progression to a lethal therapy refractory disease stage are not completely understood. Thus, elucidating novel targetable molecules and pathways promoting PCa lethality remains an unmet need. 

Advanced PCa tumors display accumulation of genome aberrations that increase tumor heterogeneity and molecular complexity. The increased genome mutational burden of LPC has an unquestionable impact on important genetic drivers of the disease. However, less is known about how highly aggressive PCa tumors cope with high chromosomal instability that should be detrimental for tumor cell survival during disease progression. 

This proposal aims to elucidate the genome instability adaptive mechanisms of aggressive PCa cells and help define novel vulnerabilities and molecular targets for advanced PCa. To achieve that, we apply a multidisciplinary approach combining genetics, genomics, biochemistry, and single cell live imaging in in vitro and in vivo models of lethal prostate cancer. 

By validating our findings in publicly available patient datasets and patient tissue samples, we aim to unveil clinically relevant mechanisms of PCa aggressiveness. At completion, the proposed research has the potential to identify novel relevant actionable molecules that may be used to develop biomarkers and therapeutic approaches to improve PCa patients’ clinical outcome. 

Do Subpopulations of Osteoblasts Regulate Prostate Cancer Progression to Metastasis?

Metastatic prostate cancer (PCa) is responsible for the deaths of nearly 32,000 American men per year. PCa frequently metastasizes to bone, where patients report the worst quality of life of all sites of metastases. 

Metastatic lesions are thought to originate from disseminated tumor cells shed from a primary tumor. Clinical evidence suggests that when PCa cells disseminate to bone, they can lie for decades in a growth-suppressive-like state. As a result, PCa patients successfully treated for primary PCa decades before may develop overt macrometastases without prior symptoms. Very little is known about events that facilitate this growth-suppressive-like state in PCa cells, and circumstances that cause PCa recurrence in bone are poorly understood. 

Upon recurrence PCa metastases perturb the balance of normal bone remodeling between bone-depositing osteoblasts (OBs) and bone-resorbing osteoclasts. In a healthy adult, there is a precise balance between OBs and osteoclasts with no net bone loss or gain. However, in late-stage bone metastatic PCa there is oftentimes net bone gain characteristic of osteoblastic disease. The newly formed bone is fragile. Osteoblastic bone lesions are associated with severe bone pain and skeletal-related events such as fractures that cause poor quality of life. 

Interestingly, emerging evidence suggests that OBs may respond differently to cancer cells during metastatic progression. According to one study, OBs help to suppress cancer cell growth in early-stage disease. In addition, our work suggests that a subpopulation of OBs reduces breast cancer (BC) cell growth in bone. Thus, the data suggests OBs have properties that alter tumor progression, especially in early stages of the disease.

Role of MITF in Lethal Prostate Cancer

*Team Members: Adam Ertel, PhD and Sandra Santasusagna, PhD

Once prostate cancer (PCa) tumors progress to an advanced therapy-resistant aggressive stage, it becomes an incurable, deadly disease. However, the understanding of the molecules and cellular processes involved in lethal prostate cancer remains limited. This proposal aims to elucidate novel transcriptional rewiring mechanisms that contribute to prostate cancer aggressiveness. 

Through the comprehensive analysis of human transcriptomic prostate cancer public databases, which include primary and metastatic samples, coupled with in vitro and in vivo patient-derived experimental models, we have identified transcriptionally-regulating mechanisms associated with tumor aggressiveness. Most relevant to this proposal, our studies point to a tumor suppressor role of the Microphthalmia Transcription Factor (MITF) in prostate cancer. Low MITF levels are associated with lethal prostate cancer and disease relapse in cancer patients. Further functional studies suggest that MITF regulates the tumor initiation capacity and proliferation of prostate cancer cells by controlling a distinct clinically relevant gene network. Moreover, computational studies suggest that MITF regulates the protein synthesis of specific key oncoproteins and prostate growth factors, such as MYC and androgen receptor (AR), that increase cancer cells’ aggressiveness. Thus, based on these results, we hypothesize that MITF suppresses a molecular cascade associated with tumor aggressiveness by regulating a specific transcriptional gene network and the translation of specific proteins. 

We will investigate this hypothesis as follows: In Aim 1, we will explore the MITF-regulated transcriptional mechanisms associated with lethal prostate cancer, focusing on the MITF isoforms to delineate their individual functions. In Aim 2, we will examine if low-MITF prostate tumors benefit the most from inhibiting the protein synthesis machinery.

At its completion, we expect to uncover key molecules and mechanisms that contribute to PCa aggressiveness and will test novel therapeutic approaches for lethal PCa. This work will also inform future studies aimed at understanding how cell rewiring mechanisms controlled by specific transcription factors contribute to lethal PCa.

Digital Health Coaching Intervention in Men with Prostate Cancer

*Team Members: Adam Dicker, MD, PhD, Sameh Gomaa, MD, and Kuang-Yi Wen, PhD

Prostate cancer is a very common condition, accounting for nearly 10% of new cancer cases in the U.S..Most treatment for prostate cancer happens outside the hospital, and much of the treatment happens in community practices. Patients take on significant responsibility for managing their cancer and would benefit from more tools to help them better manage treatment and symptoms. 

Digital health is a tool that can be used to help patients manage their cancer. One study of cancer survivors’ attitudes toward supportive care, self-management, and digital health suggests that guidance regarding physical care (66%) and healthy lifestyle programs (54%) are the highest reported needs patients have during cancer care. 

Digital health coaching—a way to provide personalized, virtual guidance for patients during their cancer treatment—is an exciting opportunity to transform the patient experience of cancer treatment without making it harder for either the patient or the care team. 

The overall objective of this project is to study the impact of digital health coaching on men with prostate cancer throughout the Greater Philadelphia area.

Investigating Chromosomal Instability Adaptation Mechanisms as a Targetable Axis in Advanced Prostate Cancer 

An estimated 31,000 men in the United States died from lethal prostate cancer (LPC) in 2019. Despite recent advances in the treatment of lethal prostate cancer (LPC), this disease remains a clinical challenge due to its inevitable treatment failure and devastating clinical outcome. The mechanisms of prostate cancer (PCa) tumor progression to a lethal therapy refractory disease stage are not completely understood. Thus, elucidating novel targetable molecules and pathways promoting PCa lethality remains an unmet need. 

Advanced PCa tumors display accumulation of genome aberrations that increase tumor heterogeneity and molecular complexity. The increased genome mutational burden of LPC has an unquestionable impact on important genetic drivers of the disease. However, less is known about how highly aggressive PCa tumors cope with high chromosomal instability that should be detrimental for tumor cell survival during disease progression. 

This proposal aims to elucidate the genome instability adaptive mechanisms of aggressive PCa cells and help define novel vulnerabilities and molecular targets for advanced PCa. To achieve that, we apply a multidisciplinary approach combining genetics, genomics, biochemistry, and single cell live imaging in in vitro and in vivo models of lethal prostate cancer. 

By validating our findings in publicly available patient datasets and patient tissue samples, we aim to unveil clinically relevant mechanisms of PCa aggressiveness. At completion, the proposed research has the potential to identify novel relevant actionable molecules that may be used to develop biomarkers and therapeutic approaches to improve PCa patients’ clinical outcomes.

PARP-1 and -2 Functions in Prostate Cancer Progression

Prostate cancer is the most frequently diagnosed non-skin cancer in men in the U.S., and results in the second highest cancer-associated mortalities in this population. While cancer confined to the prostate typically has good patient outcomes via radiation therapy or surgery, there is a significant need to better understand advanced prostate cancer and develop new means to treat it. 

PARP1 and PARP2 are important proteins involved in maintaining DNA quality that are currently under investigation as therapeutic targets in advanced prostate cancer. Last [IG1] week at a major clinical conference, it was reported that a drug that targets PARP1 and PARP2 significantly increased time to disease progression in a subset of patients with advanced prostate cancer. 

We have previously determined that targeting these PARPs with inhibitors in prostate cancer model systems causes reduced functionality of a key driver of prostate cancer (androgen receptor), and subsequently lengthens the time to disease progression in animal models. While there are some indicators of which patients may best respond to PARP inhibitors, there is more that needs to be known to make best use of them. 

Non-invasive Urine-based Genomic Assay to Detect Prostate Cancer: A Validation Study 

*Team Members: Thenappan Chandrasekar, MD 

Despite the advances in understanding its genomic and molecular basis, prostate cancer (PCa) remains the most commonly diagnosed solid malignancy in men in the U.S. and the second leading cause of cancer death. Currently, the only established method to diagnose PCa is an invasive transrectal ultrasound prostate biopsy. The majority (>66%) of biopsies show benign pathology at the expense of patient morbidity and healthcare dollars. There remains, therefore, an unmet need for a simple and non-invasive approach that will definitively diagnose PCa, determine if it is aggressive, indolent, or benign, and help guide its management. 

The era of molecular profiling has drawn much attention to genomic analysis of malignant PCa cells shed in blood and urine. In two such assays, the PCA3 and SelectMDx approved by FDA, urine is collected after digital rectal examination (DRE), malignant cells isolated and characterized by multiplex genomic fingerprints of PCa. Although innovative, the PCA3 test is not widely used, primarily due to its wide range (62%-94%) of sensitivity, specificity, positive predictive (PPV), and negative predictive value (NPV). Furthermore, the clinical utility of SelectMDx and a frequently advocated serum 4Kscore test, remains uncertain.

There is robust literature demonstrating that VPAC receptors are expressed on PCa cells. With NIH/NCI support, we designed and labeled a VPAC-specific peptide with Cu-64 that allowed us to image PCa successfully in humans. We then hypothesized that PCa cells, shed in voided urine of PCa patients, without prostate stimulation by DRE, can be imaged optically by targeting VPAC receptors, using the same peptide labeled with a fluorophore. Our preliminary results of >250 de-identified urine samples, collected from patients with PCa, benign prostatic hyperplasia and normal cases, are encouraging (sensitivity >98%) and are consistent with our hypothesis. In this investigation we propose to obtain critical information that will be required for the development of this promising noninvasive urine assay as a PCa diagnostic test.

This simple, reliable, and patient-friendly uniplex assay, when fully developed, will a) detect active, aggressive or indolent PCa, b) save patients from over-diagnosis and over-treatment, c) reduce the number of unnecessary biopsies and associated patient morbidity, and d) save millions of healthcare dollars.