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Background: African American (AA) men have higher prostate cancer (PC) incidence and PC-specific mortality than non-AA men. Socioeconomic/healthcare access and environmental factors ...contribute to the disparity in clinical outcomes. Moreover, AA PC exhibits increased inflammatory and immune response signaling, which may contribute to its aggressive behavior, but also allow for therapeutic intervention. Microsatellite instability (MSI) is a tissue-agnostic biomarker predictive of response to immune-checkpoint inhibition (pembrolizumab) that can be assessed by NGS testing of tumor tissue or circulating tumor DNA (ctDNA, liquid biopsy). The latter is particularly relevant for patients with PC, a disease which frequently metastasizes to bone and other deep sites, making conventional tissue biopsies invasive, painful and potentially risky. Methods: We retrospectively analyzed NGS results obtained via Tempus|xT tissue assay and/or Tempus|xF liquid biopsy assay for MSI, as well as clinical data (response to pembrolizumab), from 100 PC patients (53 AA) receiving androgen deprivation therapy for locally advanced, biochemically recurrent or metastatic disease at Ben Taub Hospital (BTH, a safety net hospital in Houston serving a patient population of which 91% are racial/ethnic minorities). We also analyzed de-identified NGS data from a nationwide cohort of 2090 metastatic PC patients (225 AA) previously sequenced with xT and/or xF by Tempus Labs (Chicago, IL). Results: MSI-High status (MSI-H) was detected using xT and/or xF assays in 4/100 (4%) of patients in the BTH cohort and in 62/2090 (3%) of metastatic PC patients in the nationwide Tempus Labs cohort. Specifically, within the AA PC patient population, MSI-H was detected in 2/53 (3.7%) in the BTH cohort and in 8/225 (3.6%) in the nationwide Tempus Labs cohort. For those patients who had both tissue and liquid biopsy testing, there was 100% concordance in MSI-H detection between the two assays. Genomically-driven treatment of two MSI-H AA CRPC patients with pembrolizumab resulted in prompt and durable clinical, biochemical and molecular responses, with precipitous decline in PSA levels to below detection limit, complete radiographic response of metastatic lymphadenopathy, radiographic non-progression of visceral disease (per iRECIST and PC Working Group 3 criteria) and disappearance of PC-derived ctDNA mutations in the liquid biopsy. Conclusions: MSI-H status is present in advanced AA PC at a frequency comparable to non-AA PC. Liquid biopsy (xF assay) is a minimally invasive tool that allows detection of MSI-H in PC patients, as well as longitudinal monitoring of response to treatment with pembrolizumab. Liquid biopsy conversion from positive to negative may provide reassurance that any residual lesions seen on imaging represent treated/inactive disease.
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Background: The largest US cancer health disparity exists in prostate cancer (PC), with African American (AA) men having: ~1.6-1.8-fold higher risk of developing PC; younger age and ...more advanced stage at diagnosis; increased risk of recurrence after radical prostatectomy; and up to 2.5-fold higher mortality rate relative to men of other ancestries. Access to healthcare and other socioeconomic and environmental factors contribute to the disparity in clinical outcomes. However, genetic factors may also be involved, and their role and prevalence need to be better defined, especially in real-world clinical settings, as the high cost of next-generation sequencing (NGS) may have resulted in underrepresentation of uninsured and minority patients in prior studies. Methods: We retrospectively analyzed NGS data obtained via Tempus|xT tissue assay (DNA sequencing of 648 genes in tumor and matched normal samples at 500x depth) and/or Tempus|xF liquid biopsy assay (ctDNA sequencing of 105 genes in peripheral blood samples at 5,000x depth) for germline and/or somatic mutations detected in 100 patients (53 AA) receiving androgen deprivation therapy for locally advanced, biochemically recurrent or metastatic PC at Ben Taub Hospital (BTH), a safety net hospital in Harris County/Houston serving a patient population of which 91% are racial/ethnic minorities. For confirmation, we analyzed de-identified NGS data from a nationwide cohort of 1,211 metastatic PC patients (213 AA) previously sequenced with xT and/or xF by Tempus Labs (Chicago, IL). Results: We found higher frequencies of AR (18.9%), TP53 (41.5%), SPOP (20.7%) and homologous recombination repair (HRR) pathway gene mutations, in particular BRCA2 (17%), in our AA BTH cohort, as compared to PC patients of other races/ethnicities. The latter finding was confirmed in the nationwide Tempus Labs cohort, with 91/213 (42.7%) AA patients exhibiting mutation in at least one of 14 HRR pathway genes associated with PC sensitivity to PARP inhibitors, compared to 347/998 (34.7%) non-AA patients (P < 0.05). This difference was mainly driven by higher frequency of BRCA2 (16.9%), CDK12 (8%) and PALB2 (5.2%) mutations in AA patients. In both cohorts, TMPRSS2 fusions were much less common in AA PC patients. Conclusions: The observed high frequency of mutations in key PC drivers in AA patients may reflect differences in disease biology between racial/ethnic groups or the more advanced disease presentation of AA patients due to socioeconomic factors delaying access to healthcare. Our study provides a real-world snapshot of the genomic landscape of advanced PC in a safety net hospital serving large racial/ethnic minority populations and highlights the role that NGS testing can play to improve their access to treatment with novel targeted therapies and to biomarker-based Precision Oncology clinical trials.
Abstract
Background: Prostate cancer (PC) is the single most common and second-most lethal cancer in men, with over 268,000 estimated cases and over 34,500 estimated deaths in the US in 2022. The ...Speckle-Type POZ protein (SPOP) mutant subclass of PC accounts for 10% to 15% of all primary PC cases. SPOP is an adaptor for Cullin3/Ring (CUL3-RING)-type E3 ubiquitin ligase complexes and provides substrate specificity. The Cancer Genome Atlas (TCGA) studies show that SPOP is the most frequently mutated gene in primary prostate cancer (PC). Interestingly, PC-associated SPOP mutations are always missense and occur in a heterozygous fashion. The current gap in knowledge is the lack of understanding of the role of wildtype SPOP in PC.
Methods: By utilizing prostate specific SPOP knockout (KO) mice, we recently reported increased levels of AR and MYC protein and increased cellular turnover (both proliferation and apoptosis) in the prostate luminal epithelium compared to wildtype prostates. We now characterized these mice for the expression of Cre protein and SPOP mRNA at different age using immunohistochemistry and RNA in situ hybridization. Furthermore, we performed RNA-sequencing analysis in the SPOP knockout mice and matched control littermates. Moreover, we performed RNA-seq in LNCaP, LNCaP-Abl, and RWPE1 cells following SPOP inhibition via siRNA targeting SPOP. Finally, we compared our SPOP inhibition signature from in vitro cell lines and prostate specific SPOP knockout murine model to gain insights about the role of wildtype SPOP protein in the prostate epithelium.
Result: Using our Spopfl/fl;PBCre+ model, we observed SPOP floxed cells are rapidly lost and the murine prostate epithelium was repopulated with SPOP wildtype carrying cells. Similarly, knockdown (KD) of SPOP through siRNA treatment in a panel of PC cell lines resulted in a significant reduction in cell viability. These observations suggest that SPOP is important for the normal prostate cell viability. Further transcriptomic profiling of SPOP KO (from transgenic murine model) as well as siSPOP treated in vitro prostate cell lines revealed a significant reduction in the transcriptional activity of the AR.
Conclusion: Our data illustrate for the first time a critical role for SPOP in the growth and survival of the prostate epithelium and prostate cancer cell. Our findings further validates SPOP as a important therapeutic target for the treatment of prostate cancer.
Citation Format: Kinza Rizwan, Darlene Skapura, Cammy Mason, Cristian Coarfa, Nicholas Mitsiades, Damian Young, Salma Kaochar. SPOP: An essential gene for normal and prostate tumor cells abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1705.
Castration-resistant prostate cancer (CRPC) remains highly lethal and in need of novel, actionable therapeutic targets. The pioneer factor GATA2 is a significant prostate cancer (PC) driver and is ...linked to poor prognosis. GATA2 directly promotes androgen receptor (AR) gene expression (both full-length and splice-variant) and facilitates AR binding to chromatin, recruitment of coregulators, and target gene transcription. Unfortunately, there is no clinically applicable GATA2 inhibitor available at the moment. Using a bioinformatics algorithm, we screened in silico 2650 clinically relevant drugs for a potential GATA2 inhibitor. Validation studies used cytotoxicity and proliferation assays, global gene expression analysis, RT-qPCR, reporter assay, reverse phase protein array analysis (RPPA), and immunoblotting. We examined target engagement via cellular thermal shift assay (CETSA), ChIP-qPCR, and GATA2 DNA-binding assay. We identified the vasodilator dilazep as a potential GATA2 inhibitor and confirmed on-target activity via CETSA. Dilazep exerted anticancer activity across a broad panel of GATA2-dependent PC cell lines in vitro and in a PDX model in vivo. Dilazep inhibited GATA2 recruitment to chromatin and suppressed the cell-cycle program, transcriptional programs driven by GATA2, AR, and c-MYC, and the expression of several oncogenic drivers, including AR, c-MYC, FOXM1, CENPF, EZH2, UBE2C, and RRM2, as well as of several mediators of metastasis, DNA damage repair, and stemness. In conclusion, we provide, via an extensive compendium of methodologies, proof-of-principle that a small molecule can inhibit GATA2 function and suppress its downstream AR, c-MYC, and other PC-driving effectors. We propose GATA2 as a therapeutic target in CRPC.
Abstract
Background: The largest US cancer health disparity exists in prostate cancer (PC), with African American (AA) men having a 1.6-fold increased risk of developing PC; younger age and more ...advanced stage at diagnosis; increased risk for recurrence; and a 2.5-fold increased mortality rate relative to Caucasian American (CA) men. In addition to important socioeconomic and environmental factors, this disparity is linked to incompletely understood genetic and other intrinsic biological factors. Consequently, there is an unmet need to identify actionable targets in AA PC in order to develop more effective therapeutics and, ultimately, improve clinical outcomes for AA PC patients.
Rationale/Hypothesis: The p160 Steroid Receptor Coactivator (SRC) family (SRC-1, SRC-2, and SRC-3), are master regulators of transcriptional activity. They cooperate with several oncogenic transcription factors to mediate their gene expression programs, thus representing a critical connecting signaling node in PC. We have hypothesized that the p160 SRCs underlie the higher aggressiveness of AA PC and proposed that the inhibition of the p160 SRCs can target the oncogenic transcriptional programs of AA PC, suppress AA PC cell proliferation, survival, and metastasis, and improve outcomes for AA PC patients. Data from the three p160 SRC knockout mouse models (Src1, Src2, or Src3 knockout mice) show no negative effect on mouse lifespan, suggesting the possibility of a therapeutic window.
Experimental approach: We utilized state-of-the-art in vitro assays and multi-Omics datasets to examine these hypotheses and shed light onto the role of the p160 SRCs in the intrinsic biological aggressiveness of AA PC. Recently, our BCM group synthesized an innovative panel of small molecule inhibitors (SMIs) of the p160 SRCs. We examined the efficacy of our novel p160 SRC SMIs against AA PC cell lines and patient-derived xenografts (PDXs).
Results: The p160 SRCs exhibit increased activity in AA PC compared to CA PC. They are important regulators of the transcriptional programs that drive AA PC cell proliferation, metabolism, invasion, and metastasis. Importantly, our novel p160 SRC SMIs potently suppress multiple oncogenic signaling programs in AA PC cells and inhibit cell proliferation. They also potently suppress key AA PC driver transcription factors, including AR, SREBP1, and MNX1. The latter two are - so far - undruggable oncogenic transcription factors that our extended BCM group recently discovered to be specifically overexpressed in AA PC. Furthermore, our lead SMI is well tolerated in mice and can inhibit PC cell proliferation and tumor growth in vivo.
Conclusions: We propose pharmacologic inhibition of the p160 SRC as an innovative treatment opportunity that will target several signaling pathways simultaneously and improve clinical outcomes in AA PC.
Citation Format: Salma Kaochar, Michael Ittmann, Matthew Robertson, Jin Wang, Darlene Skapura, Christel Davis, Erik Ehli, Matthew Freedman, Cristian Coarfa, Bert O'Malley, Nicholas Mitsiades. A novel therapeutic target in lethal prostate cancer in African American males abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1565.
Abstract Cancer cells frequently exhibit altered lipid metabolism to sustain their rapid growth and proliferation.Sterol Regulatory Element-Binding Proteins (SREBPs) are key transcription factors ...that orchestratelipid biosynthesis and uptake in cells. Dysregulation of SREBPs is a common feature of many cancertypes, making them attractive targets for therapeutic intervention. In this study, we present acomprehensive exploration of the potential and rationale for targeting lipid metabolism in cancerthrough the use of a small molecule inhibitor that targets activation of SREBP. We illustrate that oursmall molecule inhibitor (SMI) exhibits potent anticancer activity and effectively targets SREBPsignaling in a variety of prostate cancer models as well as in non-prostate cancer models that arelipogenesis driven. Our novel SMI induces apoptosis and reduces PCa cell proliferation, suppressescell invasion and migration. Furthermore, we illustrate that in addition to suppressing the transcriptionfactor activity of SREBPs, these novel SMIs are highly effective in suppressing both the full length andvariant androgen receptor and their signaling in prostate cancer cells. Notably, in cell and organoidmodels, these novel inhibitors exhibit synergistic anticancer activity in combination with the ARsignaling inhibitor, Enzalutamide. The anticancer activity of these inhibitors extend beyond ARdependent prostate cancer and are also effective in organoid models of neuroendocrine PCa, aparticularly drug-resistant and aggressive PC subtype. Lastly, we illustrate excellent pharmacokineticsand potent anti-tumor effects of these novel SREBP activation inhibitors using in vivo castration-resistant prostate cancer CDX tumors. Given the urgent need for novel targets in PCa, our first-in-class inhibitor represents a promising therapeutic strategy with the potential to effectively targetdysregulated lipogenesis in cancer patients. Citation Format: Dallin Lowder, Jin Na Shin, Maria E. Ruiz-Echartea, Jenny Deng, Aleksandra Rusin, Darlene Skapura, Michael Ittmann, Salma Kaochar. Exploring the multifaceted efficacy of de novo lipogenesis inhibitor in cancer therapy abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2077.
Abstract Patient-derived xenografts (PDX) model human intra- and intertumoral heterogeneity in the context of the intact tissue of immunocompromised mice. Histologic imaging via hematoxylin and eosin ...(H&E) staining is routinely performed on PDX samples, which could be harnessed for computational analysis. Prior studies of large clinical H&E image repositories have shown that deep learning analysis can identify intercellular and morphologic signals correlated with disease phenotype and therapeutic response. In this study, we developed an extensive, pan-cancer repository of >1,000 PDX and paired parental tumor H&E images. These images, curated from the PDX Development and Trial Centers Research Network Consortium, had a range of associated genomic and transcriptomic data, clinical metadata, pathologic assessments of cell composition, and, in several cases, detailed pathologic annotations of neoplastic, stromal, and necrotic regions. The amenability of these images to deep learning was highlighted through three applications: (i) development of a classifier for neoplastic, stromal, and necrotic regions; (ii) development of a predictor of xenograft-transplant lymphoproliferative disorder; and (iii) application of a published predictor of microsatellite instability. Together, this PDX Development and Trial Centers Research Network image repository provides a valuable resource for controlled digital pathology analysis, both for the evaluation of technical issues and for the development of computational image–based methods that make clinical predictions based on PDX treatment studies. Significance: A pan-cancer repository of >1,000 patient-derived xenograft hematoxylin and eosin–stained images will facilitate cancer biology investigations through histopathologic analysis and contributes important model system data that expand existing human histology repositories.
Although patient-derived xenografts (PDXs) are commonly used for preclinical modeling in cancer research, a standard approach to in vivo tumor growth analysis and assessment of antitumor activity is ...lacking, complicating comparison of different studies and determination of whether a PDX experiment has produced evidence needed to consider a new therapy promising. We present consensus recommendations for assessment of PDX growth and antitumor activity, providing public access to a suite of tools for in vivo growth analyses. We expect that harmonizing PDX study design and analysis and access to a suite of analytical tools will enhance information exchange and facilitate identification of promising novel therapies and biomarkers for guiding cancer therapy.
Abstract
Neuroendocrine Prostate Cancer (NEPC) is a lethal and aggressive variant of prostate cancer (PC), arises from prostate adenocarcinoma, mainly as a treatment resistant mechanism to Androgen ...Receptor (AR) signaling inhibitors like enzalutamide. It is independent of AR signaling and characterized by upregulation of neuroendocrine markers like CHGA, SYP, EZH2, MYCN, and CD56. Despite of therapeutic advances, this lethal subtype of PC remains undruggable and has a shorter survival period. Our lab, as well as others, have previously reported several critical functions of GATA2 in AR signaling in PC progression, but the role of GATA2 in NEPC, remained unclear. Here we investigated the role of GATA2 in NEPC using our Patient Derived Xenografts (PDXs), 3D organoid, and 2D cell line models and characterized the pharmacological potency of K-11706, a small molecule inhibitor (SMI) for GATA2 against those NEPC models.
To overcome the absence of suitable in vitro models for NEPC, first, we developed 3D organoid and 2D cell line models from NEPC PDX models generated and shared by Dr. Nora Navone at MDACC (mdpc 155-2 and mdpc 144-13). Molecular and histological characterization of these newly developed models showed retention of parent molecular and histological features of their corresponding PDXs. Immunohistochemical characterization of NEPC patient samples and PDXs shows a strong expression of GATA2 protein. Similarly, enzalutamide sensitive cells (16DCRPC cells) showed a significant upregulation of GATA2 mRNA along with neuroendocrine marker genes upon treatment with enzalutamide suggesting upregulation of GATA2 during progression from Castration Resistant Prostate Cancer (CRPC) to NEPC.
Pharmacological inhibition of GATA2 by a previously reported SMI, K-11706, efficiently reduced 3D organoid growth and cell viability in vitro, suggesting GATA2 as a potential therapeutic target for NEPC. Gene set enrichment analysis (GSEA) involving our RNA seq data from NEPC cell lines after both K-11706 treatment as well as silencing GATA2 using siRNA (siGATA2) shows a high enrichment score with respect to EZH2 inhibition in curated datasets involving EZH2 inhibition. MTT assay involving a combination of K-11706 and EPZ6438 (EZH2 inhibitor) reduced NEPC cell viability more efficiently than used alone, suggesting a combinational strategy for the treatment of this lethal aggressive PC. NEPC cell line transcriptional profiling and functional pathway analysis of the K-11706 and siGATA2 transcriptomic footprint against curated databases delineated a biological network composed of genes involved in the epithelial mesenchymal transition, hypoxia, genes regulated by NF-kB in response to TNF and KRAS signaling.
Based on these results, we propose GATA2 as an actionable therapeutic target for the treatment of NEPC, and pharmacological inhibition of both GATA2 and EZH2 by small molecule inhibitors is effective in NEPC models in vitro.
Citation Format: Amit K. Dash, Maria Elisa Ruiz Echartea, Darlene Skapura, Karen Berman de Ruiz, Jenny Jianmin Deng, Cristian Coarfa, Salma Kaochar. GATA2 a novel potential therapeutic target for treatment of neuroendocrine prostate cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3406.
Abstract Early detection of hepatocellular carcinoma (HCC) is crucial for improving patient outcomes, as curative treatments are most effective at the early stages of the disease. The lack of robust ...biomarkers, particularly a non-invasive diagnostic tool, precludes significant improvement of clinical outcomes for HCC patients. Serum metabolites are one of the best non-invasive means for determining patient prognosis. Established biomarkers for HCC including alpha-fetoprotein (AFP), have shown suboptimal performance in early disease stages. This study aimed to develop a combined metabolite and lipid panel to differentiate early-stage HCC from cirrhosis. Unbiased metabolomic and lipidomic analyses of serum samples were performed for 28 and 30 patients with early HCC and cirrhosis, respectively. We developed an unbiased high-resolution liquid chromatography mass spectrometry (LC-MS) based metabolic profiling platform and evaluated differences in the serum global metabolome and lipidome. This method enabled the detection of over 1200 metabolites and up to 800 lipid molecules in this select cohort. We identified 124 metabolites and 246 lipids that were upregulated and 208 metabolites and 73 lipids that were downregulated in HCC compared to cirrhosis. Using multiomic integrative analysis, we identified the overlap between differentially expressed metabolites and lipid and previously published transcriptomic signatures and illustrate that the overlapping signature associates with clinical disease progression. Lastly, we leveraged machine learning models to identify a minimal panel of lipids and metabolites that accurately distinguish between cirrhosis patients with HCC and without HCC. The best performing classifier was derived using Support Vector Machines, achieving a median AUC of 0.98 over 100 cross-validation iterations, and we showed that we need as little as 12 metabolite and lipids for effective discrimination between cirrhosis and early HCC. Citation Format: Hannah Powell, Elisa Ruiz, Sandra L. Grimm, Omar Najjar, Luis Olivares, Michael Scheurer, Hashem B. El Serag, Cristain Coarfa, Salma Kaochar. Metabolomic profiling of lipid and metabolite in cirrhosis patients with and without hepatocellular carcinoma abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3745.
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