Androgen deprivation and androgen receptor competition by bicalutamide induce autophagy of hormone-resistant prostate cancer cells and confer resistance to apoptosis.

BACKGROUND: Treatment of advanced prostate cancer (PCa) relies on pharmacological or surgical androgen deprivation. However, it is only temporarily efficient. After a few months or years, the tumor relapses despite the absence of androgenic stimulation: a state referred to as hormone-refractory prostate cancer (HRPCa). Although autophagy confers chemoresistance in some cancers, its role in the development of HRPCa remains unknown. METHODS: Autophagic flux was assayed by GFP-LC3 clustering, by LC3-I to LC3-II conversion and transmission electron microscopy. Cell death was detected by sub-G1 quantification and concomitant measurement of transmembrane mitochondrial potential and plasma membrane permeabilization. Inhibition of autophagy was achieved by siRNAs and pharmacological inhibitors. RESULTS: Androgen deprivation or treatment with the anti-androgen bicalutamide promoted autophagy in HRPCa-derived LNCaP cells. This effect was dramatically reduced after depletion of Atg5 and Beclin-1, two canonical autophagy genes, and was associated with an inhibition of the androgen-induced mTOR pathway. The depletion of Atg5 and Beclin-1 significantly increased the level of cell death induced by androgen deprivation or bicalutamide. Finally, the safe anti-malarial drug chloroquine, an inhibitor of autophagy, dramatically increased cell death after androgen deprivation or bicalutamide treatment. CONCLUSION: Taken together, our data suggest that autophagy is a protective mechanism against androgen deprivation in HRPCa cells and that chloroquine could restore hormone dependence. This set of data could lead to the development of new therapeutic strategy against HRPCa.

A classification of ductal plate malformations based on distinct pathogenic mechanisms of biliary dysmorphogenesis.

UNLABELLED: Ductal plate malformations (DPMs) are developmental anomalies considered to result from lack of ductal plate remodeling during bile duct morphogenesis. In mice, bile duct development is initiated by the formation of primitive ductal structures lined by two cell types, namely ductal plate cells and hepatoblasts. During ductal plate remodeling, the primitive ductal structures mature to ducts as a result from differentiation of the ductal plate cells and hepatoblasts to cholangiocytes. Here, we report this process is conserved in human fetal liver. These findings prompted us to evaluate how DPMs develop in three mouse models, namely mice with livers deficient in hepatocyte nuclear factor 6 (HNF6), HNF1ß, or cystin-1 (cpk [congenital polycystic kidney] mice). Human liver from a patient with a HNF1B/TCF2 mutation, and from fetuses affected with autosomal recessive polycystic kidney disease (ARPKD) were also analyzed. Despite the epistatic relationship between HNF6, HNF1ß, and cystin-1, the three mouse models displayed distinct morphogenic mechanisms of DPM. They all developed biliary cysts lined by cells with abnormal apicobasal polarity. However, the absence of HNF6 led to an early defect in ductal plate cell differentiation. In HNF1ß-deficient liver, maturation of the primitive ductal structures was impaired. Normal differentiation and maturation but abnormal duct expansion was apparent in cpk mouse livers and in human fetal ARPKD. CONCLUSION: DPM is the common endpoint of distinct defects initiated at distinct stages of bile duct morphogenesis. Our observations provide a new pathogenic classification of DPM.