ORCID Profile
0000-0003-4043-8296
Current Organisation
Institute of Cancer Research Sutton
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Publisher: American Association for Cancer Research (AACR)
Date: 05-2016
DOI: 10.1158/0008-5472.CAN-15-2186
Abstract: Resistance to available hormone therapies in prostate cancer has been associated with alternative splicing of androgen receptor (AR) and specifically, the expression of truncated and constitutively active AR variant 7 (AR-V7). The transcriptional activity of steroid receptors, including AR, is dependent on interactions with the HSP90 chaperone machinery, but it is unclear whether HSP90 modulates the activity or expression of AR variants. Here, we investigated the effects of HSP90 inhibition on AR-V7 in prostate cancer cell lines endogenously expressing this variant. We demonstrate that AR-V7 and full-length AR (AR-FL) were depleted upon inhibition of HSP90. However, the mechanisms underlying AR-V7 depletion differed from those for AR-FL. Whereas HSP90 inhibition destabilized AR-FL and induced its proteasomal degradation, AR-V7 protein exhibited higher stability than AR-FL and did not require HSP90 chaperone activity. Instead, HSP90 inhibition resulted in the reduction of AR-V7 mRNA levels but did not affect total AR transcript levels, indicating that HSP90 inhibition disrupted AR-V7 splicing. Bioinformatic analyses of transcriptome-wide RNA sequencing data confirmed that the second-generation HSP90 inhibitor onalespib altered the splicing of at least 557 genes in prostate cancer cells, including AR. These findings indicate that the effects of HSP90 inhibition on mRNA splicing may prove beneficial in prostate cancers expressing AR-V7, supporting further clinical investigation of HSP90 inhibitors in malignancies no longer responsive to androgen deprivation. Cancer Res 76(9) 2731–42. ©2016 AACR.
Publisher: American Association for Cancer Research (AACR)
Date: 31-05-2017
DOI: 10.1158/0008-5472.CAN-16-2169
Abstract: Epithelial-to-mesenchymal plasticity (EMP) has been linked to metastasis, stemness, and drug resistance. In prostate cancer, EMP has been associated with both suppression and activation of the androgen receptor (AR) signaling. Here we investigated the effect of the potent AR antagonist enzalutamide on EMP in multiple preclinical models of prostate cancer and patient tissues. Enzalutamide treatment significantly enhanced the expression of EMP drivers (ZEB1, ZEB2, Snail, Twist, and FOXC2) and mesenchymal markers (N-cadherin, fibronectin, and vimentin) in prostate cancer cells, enhanced prostate cancer cell migration, and induced prostate cancer transformation to a spindle, fibroblast-like morphology. Enzalutamide-induced EMP required concomitant suppression of AR signaling and activation of the EMP-promoting transcription factor Snail, as evidenced by both knockdown and overexpression studies. Supporting these findings, AR signaling and Snail expression were inversely correlated in C4-2 xenografts, patient-derived castration-resistant metastases, and clinical s les. For the first time, we elucidate a mechanism explaining the inverse relationship between AR and Snail. Specifically, we found that AR directly repressed SNAI1 gene expression by binding to specific AR-responsive elements within the SNAI1 promoter. Collectively, our findings demonstrate that de-repression of Snail and induction of EMP is an adaptive response to enzalutamide with implications for therapy resistance. Cancer Res 77(11) 3101–12. ©2017 AACR.
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 2021
DOI: 10.1016/J.CTARC.2021.100309
Abstract: Early-phase cancer clinical trials are becoming increasingly accessible for patients with advanced cancer who have exhausted standard treatment options and later phase trial options. Many of these trials mandate research tissue biopsies. Research biopsies have been perceived as ethically fraught due to the perception of potential coercion of vulnerable human subjects. We performed an audit of two years of practice to assess the safety of ultrasound (US)-guided research biopsies, and to look at the yield of a simultaneous tumour next-generation sequencing (NGS) and immunohistochemistry (IHC) molecular characterisation programme. We show that in our institution, US-guided research biopsies were safe, produced adequate tumour content and in a selected subset who underwent in-house NGS sequencing, showed a high rate of actionable mutations with 30% having a Tier 1 variant. Nevertheless, these research biopsies may only provide direct benefit for a minority of patients and we conclude with a reflection on the importance of obtaining truly informed consent.
Publisher: Springer Science and Business Media LLC
Date: 16-10-2023
Publisher: Impact Journals, LLC
Date: 02-11-2018
Publisher: American Association for Cancer Research (AACR)
Date: 12-10-2017
DOI: 10.1158/1078-0432.CCR-17-0972
Abstract: Purpose: Precise detection of copy number aberrations (CNA) from tumor biopsies is critically important to the treatment of metastatic prostate cancer. The use of targeted panel next-generation sequencing (NGS) is inexpensive, high throughput, and easily feasible, allowing single-nucleotide variant calls, but CNA estimation from this remains challenging. Experimental Design: We evaluated CNVkit for CNA identification from licon-based targeted NGS in a cohort of 110 fresh castration-resistant prostate cancer biopsies and used capture-based whole-exome sequencing (WES), array comparative genomic hybridization (aCGH), and FISH to explore the viability of this approach. Results: We showed that this method produced highly reproducible CNA results (r = 0.92), with the use of pooled germline DNA as a coverage reference supporting precise CNA estimation. CNA estimates from targeted NGS were comparable with WES (r = 0.86) and aCGH (r = 0.7) for key selected genes (BRCA2, MYC, PIK3CA, PTEN, and RB1), CNA estimation correlated well with WES (r = 0.91) and aCGH (r = 0.84) results. The frequency of CNAs in our population was comparable with that previously described (i.e., deep deletions: BRCA2 4.5% RB1 8.2% PTEN 15.5% lification: AR 45.5% gain: MYC 31.8%). We also showed, utilizing FISH, that CNA estimation can be impacted by intratumor heterogeneity and demonstrated that tumor microdissection allows NGS to provide more precise CNA estimates. Conclusions: Targeted NGS and CNVkit-based analyses provide a robust, precise, high-throughput, and cost-effective method for CNA estimation for the delivery of more precise patient care. Clin Cancer Res 23(20) 6070–7. ©2017 AACR.
Publisher: American Association for Cancer Research (AACR)
Date: 31-08-2017
DOI: 10.1158/2159-8290.CD-17-0261
Abstract: Biomarkers for more precise patient care are needed in metastatic prostate cancer. We have reported a phase II trial (TOPARP-A) of the PARP inhibitor olaparib in metastatic prostate cancer, demonstrating antitumor activity associating with homologous recombination DNA repair defects. We now report targeted and whole-exome sequencing of serial circulating cell-free DNA (cfDNA) s les collected during this trial. Decreases in cfDNA concentration independently associated with outcome in multivariable analyses (HR for overall survival at week 8: 0.19 95% CI, 0.06–0.56 P = 0.003). All tumor tissue somatic DNA repair mutations were detectable in cfDNA allele frequency of somatic mutations decreased selectively in responding patients (χ2 P & 0.001). At disease progression, following response to olaparib, multiple subclonal aberrations reverting germline and somatic DNA repair mutations (BRCA2, PALB2) back in frame emerged as mechanisms of resistance. These data support the role of liquid biopsies as a predictive, prognostic, response, and resistance biomarker in metastatic prostate cancer. Significance: We report prospectively planned, serial, cfDNA analyses from patients with metastatic prostate cancer treated on an investigator-initiated phase II trial of olaparib. These analyses provide predictive, prognostic, response, and resistance data with “second hit” mutations first detectable at disease progression, suggesting clonal evolution from treatment-selective pressure and platinum resistance. Cancer Discov 7(9) 1006–17. ©2017 AACR. See related commentary by Domchek, p. 937. See related article by Kondrashova et al., p. 984. See related article by Quigley et al., p. 999. This article is highlighted in the In This Issue feature, p. 920
Location: United Kingdom of Great Britain and Northern Ireland
Location: Portugal
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Mateus Crespo.