Etude du role du gene myc et d'autres oncogenes dans la croissance et la differenciation cellulaire in vitro

SIGLECNRS T 57019 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Cross Modulation between the Androgen Receptor Axis and Protocadherin-PC in Mediating Neuroendocrine Transdifferentiation and Therapeutic Resistance of Prostate Cancer

Castration-resistant prostate cancers (CRPCs) that relapse after androgen deprivation therapies (ADTs) are responsible for the majority of mortalities from prostate cancer (PCa). While mechanisms enabling recurrent activity of androgen receptor (AR) are certainly involved in the development of CRPC, there may be factors that contribute to the process including acquired neuroendocrine (NE) cell-like behaviors working through alternate (non-AR) cell signaling systems or AR-dependent mechanisms. In this study, we explore the potential relationship between the AR axis and a novel putative marker of NE differentiation, the human male protocadherin-PC (PCDH-PC), in vitro and in human situations. We found evidence for an NE transdifferentiation process and PCDH-PC expression as an early-onset adaptive mechanism following ADT and elucidate AR as a key regulator of PCDH-PC expression. PCDH-PC overexpression, in turn, attenuates the ligand-dependent activity of the AR, enabling certain prostate tumor clones to assume a more NE phenotype and promoting their survival under diverse stress conditions. Acquisition of an NE phenotype by PCa cells positively correlated with resistance to cytotoxic agents including docetaxel, a taxane chemotherapy approved for the treatment of patients with metastatic CRPC. Furthermore, knockdown of PCDH-PC in cells that have undergone an NE transdifferentiation partially sensitized cells to docetaxel. Together, these results reveal a reciprocal regulation between the AR axis and PCDH-PC signals, observed both in vitro and in vivo, with potential implications in coordinating NE transdifferentiation processes and progression of PCa toward hormonal and chemoresistance

Cross modulation between the androgen receptor axis and protocadherin-PC in mediating neuroendocrine transdifferentiation and therapeutic resistance of prostate cancer.: PCDH-PC/AR cross-talk in driving NE differentiation

International audienceCastration-resistant prostate cancers (CRPCs) that relapse after androgen deprivation therapies (ADTs) are responsible for the majority of mortalities from prostate cancer (PCa). While mechanisms enabling recurrent activity of androgen receptor (AR) are certainly involved in the development of CRPC, there may be factors that contribute to the process including acquired neuroendocrine (NE) cell-like behaviors working through alternate (non-AR) cell signaling systems or AR-dependent mechanisms. In this study, we explore the potential relationship between the AR axis and a novel putative marker of NE differentiation, the human male protocadherin-PC (PCDH-PC), in vitro and in human situations. We found evidence for an NE transdifferentiation process and PCDH-PC expression as an early-onset adaptive mechanism following ADT and elucidate AR as a key regulator of PCDH-PC expression. PCDH-PC overexpression, in turn, attenuates the ligand-dependent activity of the AR, enabling certain prostate tumor clones to assume a more NE phenotype and promoting their survival under diverse stress conditions. Acquisition of an NE phenotype by PCa cells positively correlated with resistance to cytotoxic agents including docetaxel, a taxane chemotherapy approved for the treatment of patients with metastatic CRPC. Furthermore, knockdown of PCDH-PC in cells that have undergone an NE transdifferentiation partially sensitized cells to docetaxel. Together, these results reveal a reciprocal regulation between the AR axis and PCDH-PC signals, observed both in vitro and in vivo, with potential implications in coordinating NE transdifferentiation processes and progression of PCa toward hormonal and chemoresistance

Oncologic outcome after extraperitoneal laparoscopic radical prostatectomy: midterm follow-up of 1115 procedures.

International audienceBACKGROUND: Although the first laparoscopic radical prostatectomy was performed in 1997, few midterm oncologic data have been published for the extraperitoneal procedure. OBJECTIVE: To determine the oncologic outcome of extraperitoneal laparoscopic radical prostatectomy (ELRP). DESIGN, SETTING, AND PARTICIPANTS: From 2000 to 2007, 1115 consecutive patients underwent ELRP for a localized prostate cancer at our department. Follow-up was scheduled and standardized for all patients and recorded into a prospective database. Median postoperative follow-up was 35.6 mo. INTERVENTION: All ELRP were performed by three surgeons at the Department of Urology, Hospital Henri Mondor, Créteil, France. MEASUREMENTS: Biochemical recurrence was defined by prostate-specific antigen level > or =0.2 ng/ml. RESULTS AND LIMITATIONS: In pN0/pNx cancers, postoperative stage was pT2 in 664 patients (59.5%), pT3 in 350 patients (31.4%), and pT4 in 77 patients (6.9%). Positive lymph nodes were reported in 24 patients (2.2%). Margins were positive in 16.1% and 34.6% of pT2 and pT3 cancers, respectively. Final Gleason score was 7 in 126 men (11.3%). Overall prostate-specific antigen (PSA) recurrence-free survival was 83% at 5 yr. The 5-yr progression-free survival rates were 93.4% for pT2, 74.5% for pT3a, and 55.0% for pT3b tumors, respectively. Multivariate Cox model showed that PSA, Gleason score, pT category, nodal status, and surgical margins were significant independent predictors of biochemical recurrence-free survival. CONCLUSIONS: This assessment of oncologic results demonstrates that ELRP is a safe and effective procedure. On the basis of midterm follow-up data, the prognostic factors of PSA after ELRP failure are the same as those described previously in transperitoneal or open retropubic approaches. The oncologic results of ELRP also are in line with those reported with the use of the retropubic or the transperitoneal laparoscopic approaches

CRIPTO overexpression promotes mesenchymal differentiation in prostate carcinoma cells through parallel regulation of AKT and FGFR activities

Members of the EGF-CFC (Cripto, FRL-1, Cryptic) protein family are increasingly recognized as key mediators of cell movement and cell differentiation during vertebrate embryogenesis. The founding member of this protein family, CRIPTO, is overexpressed in various human carcinomas. Yet, the biological role of CRIPTO in this setting remains unclear. Here, we find CRIPTO expression as especially high in a subgroup of primary prostate carcinomas with poorer outcome, wherein resides cancer cell clones with mesenchymal traits. Experimental studies in PCa models showed that one notable function of CRIPTO expression in prostate carcinoma cells may be to augment PI3K/AKT and FGFR1 signaling, which promotes epithelial-mesenchymal transition and sustains a mesenchymal state. In the observed signaling events, FGFR1 appears to function parallel to AKT, and the two pathways act cooperatively to enhance migratory, invasive and transformation properties specifically in the CRIPTO overexpressing cells. Collectively, these findings suggest a novel molecular network, involving CRIPTO, AKT, and FGFR signaling, in favor of the emergence of mesenchymal-like cancer cells during the development of aggressive prostate tumors

Class III beta-tubulin expression predicts prostate tumor aggressiveness and patient response to docetaxel-based chemotherapy.

International audienceExpression of class III β-tubulin (βIII-tubulin) correlates with tumor progression and resistance to taxane-based therapies for several human malignancies, but its use as a biomarker of tumor behavior in prostate cancer (PCa) remains largely unexplored. Here, we describe βIII-tubulin immunohistochemical staining patterns of prostate tumors obtained from a broad spectrum of PCa patients, some of whom subsequently received docetaxel therapy for castration-resistant PCa (CRPC). Elevated βIII-tubulin expression was significantly associated with tumor aggressiveness in PCa patients with presumed localized disease, as it was found to be an independent marker of biochemical recurrence after treatment. Additionally, βIII-tubulin expression in tumor cells was an independent predictor of lower overall survival for patients receiving docetaxel-based chemotherapy for CRPC. Manipulation of βIII-tubulin expression in human PCa cell lines using a human βIII-tubulin expression vector or βIII-tubulin small interfering RNA altered cell survival in response to docetaxel treatment in a manner that supports a role for βIII-tubulin expression as a mediator of PCa cell resistance to docetaxel therapy. Our findings suggest a role for βIII-tubulin as candidate theranostic biomarker to predict the response to docetaxel-based chemotherapy as well as to target for treatment of docetaxel-resistant CRPC

Prostate Cancer Detection Rate in Patients with Repeated Extended 21-Sample Needle Biopsy.

International audienceBACKGROUND: Prevalence of prostate cancer (PCa) after a negative first extended prostate needle biopsy protocol is unknown. OBJECTIVE: To evaluate the prevalence of significant PCa in patients who have had a negative first extended prostate biopsy protocol. DESIGN, SETTING, AND PARTICIPANTS: Between March 2001 and May 2007, 2500 consecutive patients underwent an extended protocol of 21 biopsies. Of 953 patients who had a negative first extended prostate biopsy procedure, 231 patients underwent a second or more set of 21-core biopsies. Indications for repeated biopsies were persistently elevated prostate-specific antigen (PSA), PSA increase during the follow-up, or prior prostatic intraepithelial neoplasia (PIN), or atypical small acinar proliferation (ASAP). INTERVENTION: All participants underwent at least two extended prostate needle biopsy protocols. MEASUREMENTS: Clinical and pathologic factors (age, PSA, PSA doubling time, PIN, ASAP, digital rectal exam [DRE]) were analyzed for their ability to predict positive biopsy, and tumour parameters were assessed in patients undergoing radical prostatectomy. RESULTS AND LIMITATIONS: Second, third, and fourth extended 21-sample biopsy procedures yielded a diagnosis of PCa in 18%, 17%, and 14% of patients respectively. Patients with prior PIN had 16% risk of prostate cancer; patients with ASAP had a 42% risk. The mean number of positive cores was 2.19. Prostate volume and PSA density were statistically significant predictors of positive biopsy (p0.5 cc, Gleason >/=7 and/or pT3). CONCLUSIONS: Negative first extended biopsies should not reassure a patient of not having PCa. However, prostate cancers detected after two or more sets of extended procedures, appear to be localized (intracapsular disease) and well-differentiated prostate cancers, although they are still clinically significant

The Neuropilin-1/PKC axis promotes neuroendocrine differentiation and drug resistance of prostate cancer

International audienceAbstract Background Neuroendocrine prostate cancer (NEPC) is a multi-resistant variant of prostate cancer (PCa) that has become a major challenge in clinics. Understanding the neuroendocrine differentiation (NED) process at the molecular level is therefore critical to define therapeutic strategies that can prevent multi-drug resistance. Methods Using RNA expression profiling and immunohistochemistry, we have identified and characterised a gene expression signature associated with the emergence of NED in a large PCa cohort, including 169 hormone-naïve PCa (HNPC) and 48 castration-resistance PCa (CRPC) patients. In vitro and preclinical in vivo NED models were used to explore the cellular mechanism and to characterise the effects of castration on PCa progression. Results We show for the first time that Neuropilin-1 (NRP1) is a key component of NED in PCa cells. NRP1 is upregulated in response to androgen deprivation therapies (ADT) and elicits cell survival through induction of the PKC pathway. Downmodulation of either NRP1 protein expression or PKC activation suppresses NED, prevents tumour evolution toward castration resistance and increases the efficacy of docetaxel-based chemotherapy in preclinical models in vivo. Conclusions This study reveals the NRP1/PKC axis as a promising therapeutic target for the prevention of neuroendocrine castration-resistant variants of PCa and indicates NRP1 as an early transitional biomarker