Modeling lethal prostate cancer variant with small cell carcinoma features [genomic profile]
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ABSTRACT: Purpose: Small-cell prostate carcinoma (SCPC) morphology predicts for a distinct clinical behavior, resistance to androgen ablation, and frequent but short responses to chemotherapy. The model systems we report reflect the biology of the human disease and can be used to improve our understanding of SCPC and to develop new therapeutic strategies for it. Experimental Design: We developed a set of CRPC xenografts and examined their fidelity to their human tumors of origin. We compared the expression and genomic profiles of SCPC and large cell neuroendocrine carcinoma (LCNEC) xenografts to those of typical prostate adenocarcinoma xenografts and used a panel of 60 human tumors to validate our findings using immunohistochemistry. Results: We show that SCPC and LCNEC xenograft models retain high fidelity to their human tumors of origin and are characterized by a marked upregulation of UBE2C and other M-phase cell cycle genes in the absence of AR, retinoblastoma (RB1) and cyclin D1 (CCND1) expression and confirm these findings in a panel of CRPC patients’ samples. In addition, array comparative genomic hybridization of the xenografts showed that the SCPC/LCNEC tumors display more copy number variations than the adenocarcinoma counterparts and that there is amplification of the UBE2C locus and microdeletions of RB1 in a subset of these, but no AR nor CCND1 deletions. Moreover, the AR, RB1, and CCND1 promoters showed no CpG methylation in the SCPC xenografts. Conclusion: Modeling human prostate cancer with xenografts allows in-depth and detailed studies of its underlying biology. The detailed clinical annotation of the donor tumors enables associations of anticipated relevance to be made. Futures studies in the xenografts will address the functional significance of the findings. Total of 6 samples
Project description:Purpose: Small-cell prostate carcinoma (SCPC) morphology predicts for a distinct clinical behavior, resistance to androgen ablation, and frequent but short responses to chemotherapy. The model systems we report reflect the biology of the human disease and can be used to improve our understanding of SCPC and to develop new therapeutic strategies for it. Experimental Design: We developed a set of CRPC xenografts and examined their fidelity to their human tumors of origin. We compared the expression and genomic profiles of SCPC and large cell neuroendocrine carcinoma (LCNEC) xenografts to those of typical prostate adenocarcinoma xenografts and used a panel of 60 human tumors to validate our findings using immunohistochemistry. Results: We show that SCPC and LCNEC xenograft models retain high fidelity to their human tumors of origin and are characterized by a marked upregulation of UBE2C and other M-phase cell cycle genes in the absence of AR, retinoblastoma (RB1) and cyclin D1 (CCND1) expression and confirm these findings in a panel of CRPC patients’ samples. In addition, array comparative genomic hybridization of the xenografts showed that the SCPC/LCNEC tumors display more copy number variations than the adenocarcinoma counterparts and that there is amplification of the UBE2C locus and microdeletions of RB1 in a subset of these, but no AR nor CCND1 deletions. Moreover, the AR, RB1, and CCND1 promoters showed no CpG methylation in the SCPC xenografts. Conclusion: Modeling human prostate cancer with xenografts allows in-depth and detailed studies of its underlying biology. The detailed clinical annotation of the donor tumors enables associations of anticipated relevance to be made. Futures studies in the xenografts will address the functional significance of the findings. 22 samples were analysed, that included MDA PCa 79 (n = 3), 117-9 (n = 3), 130 (n = 2), 144-4 (n = 4), 144-13 (n = 5), 146-10 (n = 3), 155-2 (n = 1), and 155-12 (n = 1). MDA PCA 79, 117-9 and 130 samples had the pathologic characteristics of prostate adenocarcinoma and were compared against MDA PCA 144-4, 144-13, 146-10 and 155-12 that have the pathologic features of prostate small cell/ large cell neuroendocrine carcinoma
Project description:Purpose: Small-cell prostate carcinoma (SCPC) morphology predicts for a distinct clinical behavior, resistance to androgen ablation, and frequent but short responses to chemotherapy. The model systems we report reflect the biology of the human disease and can be used to improve our understanding of SCPC and to develop new therapeutic strategies for it. Experimental Design: We developed a set of CRPC xenografts and examined their fidelity to their human tumors of origin. We compared the expression and genomic profiles of SCPC and large cell neuroendocrine carcinoma (LCNEC) xenografts to those of typical prostate adenocarcinoma xenografts and used a panel of 60 human tumors to validate our findings using immunohistochemistry. Results: We show that SCPC and LCNEC xenograft models retain high fidelity to their human tumors of origin and are characterized by a marked upregulation of UBE2C and other M-phase cell cycle genes in the absence of AR, retinoblastoma (RB1) and cyclin D1 (CCND1) expression and confirm these findings in a panel of CRPC patients’ samples. In addition, array comparative genomic hybridization of the xenografts showed that the SCPC/LCNEC tumors display more copy number variations than the adenocarcinoma counterparts and that there is amplification of the UBE2C locus and microdeletions of RB1 in a subset of these, but no AR nor CCND1 deletions. Moreover, the AR, RB1, and CCND1 promoters showed no CpG methylation in the SCPC xenografts. Conclusion: Modeling human prostate cancer with xenografts allows in-depth and detailed studies of its underlying biology. The detailed clinical annotation of the donor tumors enables associations of anticipated relevance to be made. Futures studies in the xenografts will address the functional significance of the findings.
Project description:Purpose: Small-cell prostate carcinoma (SCPC) morphology predicts for a distinct clinical behavior, resistance to androgen ablation, and frequent but short responses to chemotherapy. The model systems we report reflect the biology of the human disease and can be used to improve our understanding of SCPC and to develop new therapeutic strategies for it. Experimental Design: We developed a set of CRPC xenografts and examined their fidelity to their human tumors of origin. We compared the expression and genomic profiles of SCPC and large cell neuroendocrine carcinoma (LCNEC) xenografts to those of typical prostate adenocarcinoma xenografts and used a panel of 60 human tumors to validate our findings using immunohistochemistry. Results: We show that SCPC and LCNEC xenograft models retain high fidelity to their human tumors of origin and are characterized by a marked upregulation of UBE2C and other M-phase cell cycle genes in the absence of AR, retinoblastoma (RB1) and cyclin D1 (CCND1) expression and confirm these findings in a panel of CRPC patients’ samples. In addition, array comparative genomic hybridization of the xenografts showed that the SCPC/LCNEC tumors display more copy number variations than the adenocarcinoma counterparts and that there is amplification of the UBE2C locus and microdeletions of RB1 in a subset of these, but no AR nor CCND1 deletions. Moreover, the AR, RB1, and CCND1 promoters showed no CpG methylation in the SCPC xenografts. Conclusion: Modeling human prostate cancer with xenografts allows in-depth and detailed studies of its underlying biology. The detailed clinical annotation of the donor tumors enables associations of anticipated relevance to be made. Futures studies in the xenografts will address the functional significance of the findings.
Project description:Continued androgen receptor (AR) signaling is an established mechanism underlying castration-resistant prostate cancer (CRPC), and suppression of AR signaling remains a therapeutic goal of CRPC therapy. Constitutively active androgen receptor splicing variants (AR-Vs) lack the AR ligand-binding domain (AR-LBD), the intended target of androgen deprivation therapies (ADT) including new CRPC therapies such as abiraterone and MDV3100. While the canonical full-length AR (AR-FL) and AR-Vs are both increased in CRPC, their expression regulation, associated transcriptional programs, functional relationships, and respective roles in mediating responses to endocrine therapies have not been dissected. In this study, we show that suppression of canonical AR-FL signaling by targeting AR-LBD leads to increased AR-V expression in two cell line models of CRPC. Importantly, treatment-induced AR-Vs activate a distinct expression signature enriched for cell cycle genes without requiring the presence of AR-FL. Conversely, activation of AR-FL signaling suppresses the AR-V signature but activates expression programs mainly associated with macromolecular synthesis, metabolism, and differentiation. In prostate cancer cells and CRPC xenografts treated with MDV3100 and abiraterone, increased expression of two constitutively active AR-Vs, AR-V7 and ARV567ES, but not AR-FL, parallels increased expression of the AR-driven cell cycle gene UBE2C. In addition, protein expression of AR-V7, but not AR-FL, is positively correlated with UBE2C in clinical CRPC specimens. The cumulative in vitro and in vivo evidence support an adaptive shift toward AR-V-mediated signaling in at least a subset of CRPC tumors as the AR-LBD is rendered inactive, suggesting an important mechanism contributing to drug resistance to CRPC therapies. LNCaP cells lacking AR-V were transfected with AR-V7 with or without androgen stimulation of AR-FL (4 conditions); LNCaP95 cells expressing AR-Vs were treated with control siRNA or siRNA trageting AR-LBD or AR-DBD, with or without androgen stimulation of AR-FL (6 conditions); VCaP cells expressing AR-Vs in the presence of androgen were treated with control siRNA, siRNA trageting AR-LBD, DMSO or MDV3100 to inhibit AR-FL (4 conditions). Total 14 arrays with no replicates.
Project description:Continued androgen receptor (AR) signaling is an established mechanism underlying castration-resistant prostate cancer (CRPC), and suppression of AR signaling remains a therapeutic goal of CRPC therapy. Constitutively active androgen receptor splicing variants (AR-Vs) lack the AR ligand-binding domain (AR-LBD), the intended target of androgen deprivation therapies (ADT) including new CRPC therapies such as abiraterone and MDV3100. While the canonical full-length AR (AR-FL) and AR-Vs are both increased in CRPC, their expression regulation, associated transcriptional programs, functional relationships, and respective roles in mediating responses to endocrine therapies have not been dissected. In this study, we show that suppression of canonical AR-FL signaling by targeting AR-LBD leads to increased AR-V expression in two cell line models of CRPC. Importantly, treatment-induced AR-Vs activate a distinct expression signature enriched for cell cycle genes without requiring the presence of AR-FL. Conversely, activation of AR-FL signaling suppresses the AR-V signature but activates expression programs mainly associated with macromolecular synthesis, metabolism, and differentiation. In prostate cancer cells and CRPC xenografts treated with MDV3100 and abiraterone, increased expression of two constitutively active AR-Vs, AR-V7 and ARV567ES, but not AR-FL, parallels increased expression of the AR-driven cell cycle gene UBE2C. In addition, protein expression of AR-V7, but not AR-FL, is positively correlated with UBE2C in clinical CRPC specimens. The cumulative in vitro and in vivo evidence support an adaptive shift toward AR-V-mediated signaling in at least a subset of CRPC tumors as the AR-LBD is rendered inactive, suggesting an important mechanism contributing to drug resistance to CRPC therapies.
Project description:Relatively little is known about how changes in gene copy number (CN) and gene CpG methylation interact to affect specific pathways in metastatic castration-resistant prostate cancer (CRPC). Oligonucleotide array comparative genomic hybridization (aCGH) was performed on DNA isolated from 15 metastatic CRPC samples. Commonly aberrant genes were evaluated in a confirmatory fashion using PCR, aCGH data from primary tumors, and existing CRPC expression data. Array-based comprehensive CpG methylation was assessed on the same sample set. A total of 495 genes (79 gained, 416 deleted) were CN aberrant in ?66% of the samples by aCGH, and 77 (9 amplified, 68 deleted) had statistically concordant expression including gain of AR and loss of PTEN and RB1. Significant CN differences were seen between the genomes of patients with AR-amplified and AR-unamplified tumors, including common loss of AR repressors in AR-unamplified tumors. The majority of CRPC samples were hypermethylated compared to benign prostate tissue. Simultaneous methylation and heterozygous gene deletion occurred in the tumor suppressor RB1 and in HSD17B2, responsible for testosterone metabolism. Establishment of a comprehensive methylation signature and coupling of epigenomic and structural analyses sheds light on the alterations that allow CRPC to circumvent hormonal therapy and may provide new drug targets for what is currently an incurable disease state. 15 tumor samples taken from 14 men with metastatic castration resistant prostate cancer were analyzed, including two samples from the same patient. No control samples were used for this experiment.
Project description:Relatively little is known about how changes in gene copy number (CN) and gene CpG methylation interact to affect specific pathways in metastatic castration-resistant prostate cancer (CRPC). Oligonucleotide array comparative genomic hybridization (aCGH) was performed on DNA isolated from 15 metastatic CRPC samples. Commonly aberrant genes were evaluated in a confirmatory fashion using PCR, aCGH data from primary tumors, and existing CRPC expression data. Array-based comprehensive CpG methylation was assessed on the same sample set. A total of 495 genes (79 gained, 416 deleted) were CN aberrant in ≥66% of the samples by aCGH, and 77 (9 amplified, 68 deleted) had statistically concordant expression including gain of AR and loss of PTEN and RB1. Significant CN differences were seen between the genomes of patients with AR-amplified and AR-unamplified tumors, including common loss of AR repressors in AR-unamplified tumors. The majority of CRPC samples were hypermethylated compared to benign prostate tissue. Simultaneous methylation and heterozygous gene deletion occurred in the tumor suppressor RB1 and in HSD17B2, responsible for testosterone metabolism. Establishment of a comprehensive methylation signature and coupling of epigenomic and structural analyses sheds light on the alterations that allow CRPC to circumvent hormonal therapy and may provide new drug targets for what is currently an incurable disease state.
Project description:Enzalutamide (ENZ) is a potent androgen receptor (AR) antagonist with activity in castration-resistant prostate cancer (CRPC); however, progression to ENZ-resistant (ENZ-R) CRPC frequently occurs with rising serum PSA levels, implicating AR full length (ARFL) or variants (AR-Vs) in disease progression. To define functional roles of ARFL and AR-Vs in ENZ-R CRPC, we designed 3 antisense oligonucleotides (ASO) targeting exon 1, intron 1, and exon 8 in AR pre-mRNA to knockdown either ARFL alone, or ARFL plus AR-Vs, and examined their respective effects in LNCaP-derived ENZ-R, as well as M12 and 22Rv1, cells. ENZ-R LNCaP xenografts express high levels of both ARFL and AR-V7 compared to CRPC LNCaP xenografts. In particular, ARFL levels were ~20-fold higher than AR-V7. ENZ-R LNCaP sub-lines, derived by selection from the ENZ xenografts, also expressed uniformly high levels of ARFL and AR-V7 compared to CRPC LNCaP cells. In addition, both ARFL and AR-V7 are highly expressed in the nuclear fractions of ENZ-R-LNCaP. In ENZ-R LNCaP cells, knockdown of ARFL alone, or ARFL plus AR-Vs, similarly induced apoptosis, suppressed cell growth and AR-regulated gene expression in vitro, and delayed tumour growth in vivo. In 22Rv1 cells that are inherently resistant to ENZ, knockdown of both ARFL and AR-Vs more potently suppressed cell growth, AR transcriptional activity and AR-regulated gene expression than knockdown of ARFL alone. These data indicate the AR is an important driver of ENZ resistance, and while the contributions of ARFL and AR-Vs can vary across cell systems, ARFL is the key driver in the ENZ-R LNCaP model. AR targeting strategies against both ARFL and AR-Vs is a rational approach for AR-dependent CRPC. CRPC and ENZ-R LNCaP xenografts were generated as described in: Gleave, M.E., et al., Serum prostate specific antigen levels in mice bearing human prostate LNCaP tumors are determined by tumor volume and endocrine and growth factors. Cancer Res, 1992. 52(6): p. 1598-605.
Project description:The neuroendocrine (NE) phenotype is associated with the development of metastatic castration-resistant prostate cancer (CRPC). Our objective was to characterize the molecular features of the NE phenotype in CRPC. Expression of chromogranin A (CHGA), synaptophysin (SYP), androgen receptor (AR), and prostate-specific antigen (PSA) was analyzed by immunohistochemistry (IHC) in 155 CRPC metastases from 50 patients and in 24 LuCaP prostate cancer patient-derived xenografts (PDX). Co-expression of CHGA and SYP in >30% of cells was observed in 22 of 155 metastases (9 patients); 11 of the 22 metastases were AR+/PSA+ (6 patients), 11/22 were AR-/PSA- (4 patients), and 4/24 LuCaP PDXs were AR-/PSA-. Seventy-one of 155 metastases and the 24 LuCaP xenograft lines were analyzed by whole genome microarrays. By IHC, of the 71 metastases analyzed by whole genome microarrays, 5 metastases were CHGA+/SYP+/AR- and 5 were CHGA+/SYP+/AR+. Only CHGA+/SYP+ metastases had a NE transcript signature. The neuronal transcriptional regulator SRRM4 transcript was associated with the NE signature in CHGA+/SYP+ metastases and all CHGA+/SYP+ LuCaP xenografts. Additionally, expression of SRRM4 in the LuCaP NE xenografts correlated with a splice variant of REST that lacks the transcriptional repressor domain. In conclusion, (a) metastatic NE status can be heterogeneous in the same patient, (b) the CRPC NE molecular phenotype can be defined by CHGA+/SYP+ dual positivity, (c) the NE phenotype is not necessarily associated with the loss of AR activity, and (d) the splicing of REST by SRRM4 could promote the NE phenotype in CRPC. Custom Agilent 44K whole human genome expression oligonucleotide microarrays were used to profile 24 LuCaP PCa xenograft lines and 71 CRPC metastases from 47 patients. RNA was amplified prior to hybridization against a common reference pool of prostate tumor cell lines.
Project description:In castration-resistant prostate cancer (CRPC), clinical response to androgen receptor (AR) antagonists is limited mainly due to AR-variants expression and restored AR signaling. The metabolite spermine is most abundant in prostate and it decreases as prostate cancer progresses, but its functions remain poorly understood. Here, we show spermine inhibits full-length androgen receptor (AR-FL) and androgen receptor splice variant 7 (AR-V7) signaling and suppresses CRPC cell proliferation by directly binding and inhibiting protein arginine methyltransferase PRMT1. Spermine reduces H4R3me2a modification at the AR locus and suppresses AR binding as well as H3K27ac modification levels at AR target genes. Spermine supplementation restrains CRPC growth in vivo. PRMT1 inhibition also suppresses AR-FL and AR-V7 signaling and reduces CRPC growth. Collectively, we demonstrate spermine as an anticancer metabolite by inhibiting PRMT1 to transcriptionally inhibit AR-FL and AR-V7 signaling in CRPC, and we indicate spermine and PRMT1 inhibition as powerful strategies overcoming limitations of current AR-based therapies in CRPC.