cytochrome-c-t and Prostatic-Neoplasms--Castration-Resistant

Abiraterone acetate (AA) is a selective inhibitor of CYP17 α-hydroxylase, which is crucial for androgen biosynthesis. Apigenin (Api) is a natural plant-derived flavonoid with potent antiproliferative and antimigration effects.. We aimed to investigate the possible role of Api in combination with the androgen receptor inhibitor AA in the treatment of androgen-sensitive human prostate cancer LNCaP cells.. The cells were either exposed to 10 μM AA, 25 μM Api, or in combination for 48 hours, then the viability rate was determined by the MTT test, whilst apoptosis and cell cycle phases were assessed by image-based cytometry. The expression of selected mRNA and proteins were evaluated by RT-qPCR and Western blot, respectively.. The combination of AA and Api significantly inhibited LNCaP as well as androgen-insensitive PC3 cell survival in a manner more marked than observed with either single treatment. Co-administration of Api with AA triggered apoptosis. This effect was demonstrated by Hoechst staining, and up-regulation of Bax, cytochrome c, caspase -3, and - 8 and down-regulation of Bcl-2 expression confirmed the effect. AA and Api each individually arrested the cell cycle in the G1 phase, with dual applications, leading to no further increase in the effect produced. The expression of NF-κB p105/p50 and the phosphorylation of AKT markedly decreased after apigenin treatment, with combination treatment leading to a favourable effect in terms of further augmenting the reduction.. The co-administration of Api with AA strongly enhanced the efficacy of AA therapy in the treatment of prostate cancer cells. These data suggested that the combination of AA and Api would be a potential chemotherapeutic strategy against prostate cancer.

Topics: Abiraterone Acetate; Androgens; Apigenin; Apoptosis; bcl-2-Associated X Protein; Caspases; Castration; Cytochromes c; Flavonoids; Humans; Male; NF-kappa B; Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; Proto-Oncogene Proteins c-akt; Receptors, Androgen; RNA, Messenger; Steroid 17-alpha-Hydroxylase

Prostate cancer is the second leading cause of cancer-related death in men. Two classic cancer hallmarks are a metabolic switch from oxidative phosphorylation (OxPhos) to glycolysis, known as the Warburg effect, and resistance to cell death. Cytochrome

Topics: Acetylation; Animals; Apoptosis; Cardiolipins; Caspase 3; Cell Line, Tumor; Crystallography, X-Ray; Cytochromes c; Electron Transport Complex IV; Humans; Lysine; Male; Mice; Molecular Dynamics Simulation; Mutation; Oxidation-Reduction; Oxygen Consumption; Peroxidase; Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; Reactive Oxygen Species; Warburg Effect, Oncologic; Xenograft Model Antitumor Assays

Prostate cancer (PC) is one of the leading causes of death in males. Available treatments often lead to the appearance of chemoresistant foci and metastases, with mechanisms still partially unknown. Within tumour mass, autophagy may promote cell survival by enhancing cancer cells tolerability to different cell stresses, like hypoxia, starvation or those triggered by chemotherapic agents. Because of its connection with the apoptotic pathways, autophagy has been differentially implicated, either as prodeath or prosurvival factor, in the appearance of more aggressive tumours. Here, in three PC cells (LNCaP, PC3, and DU145), we tested how different autophagy inducers modulate docetaxel-induced apoptosis. We selected the mTOR-independent disaccharide trehalose and the mTOR-dependent macrolide lactone rapamycin autophagy inducers. In castration-resistant PC (CRPC) PC3 cells, trehalose specifically prevented intrinsic apoptosis in docetaxel-treated cells. Trehalose reduced the release of cytochrome c triggered by docetaxel and the formation of aberrant mitochondria, possibly by enhancing the turnover of damaged mitochondria via autophagy (mitophagy). In fact, trehalose increased LC3 and p62 expression, LC3-II and p62 (p62 bodies) accumulation and the induction of LC3 puncta. In docetaxel-treated cells, trehalose, but not rapamycin, determined a perinuclear mitochondrial aggregation (mito-aggresomes), and mitochondria specifically colocalized with LC3 and p62-positive autophagosomes. In PC3 cells, rapamycin retained its ability to activate autophagy without evidences of mitophagy even in presence of docetaxel. Interestingly, these results were replicated in LNCaP cells, whereas trehalose and rapamycin did not modify the response to docetaxel in the ATG5-deficient (autophagy resistant) DU145 cells. Therefore, autophagy is involved to alter the response to chemotherapy in combination therapies and the response may be influenced by the different autophagic pathways utilized and by the type of cancer cells.

Topics: Antineoplastic Agents; Apoptosis; Autophagy; Cell Line, Tumor; Cytochromes c; Docetaxel; Humans; Male; Microtubule-Associated Proteins; Mitochondria; Mitophagy; PC-3 Cells; Prostatic Neoplasms, Castration-Resistant; RNA-Binding Proteins; Sirolimus; TOR Serine-Threonine Kinases; Trehalose

Galeterone (Gal) is a first-in-class multi-target oral small molecule that will soon enter pivotal phase III clinical trials in castration resistant prostate cancer (CRPC) patients. Gal disrupts androgen receptor (AR) signaling via inhibition of CYP17, AR antagonism and AR degradation. Resistance to current therapy is attributed to up-regulation of full-length AR (fAR), splice variants AR (AR-Vs) and AR mutations. The effects of gal and VNPT55 were analyzed on f-AR and AR-Vs (AR-V7/ARv567es) in LNCaP, CWR22Rv1 and DU145 (transfected with AR-Vs) human PC cells in vitro and CRPC tumor xenografts. Galeterone/VNPT55 decreased fAR/AR-V7 mRNA levels and implicates Mdm2/CHIP enhanced ubiquitination of posttranslational modified receptors, targeting them for proteasomal degradation. Gal and VNPT55 also induced significant apoptosis in PC cells via increased Bax/Bcl2 ratio, cytochrome-c release with concomitant cleavage of caspase 3 and PARP. More importantly, gal and VNPT55 exhibited strong in vivo anti-CRPC activities, with no apparent host toxicities. This study demonstrate that gal and VNPT55 utilize cell-based mechanisms to deplete both fAR and AR-Vs. Importantly, the preclinical activity profiles, including profound apoptotic induction and inhibition of CRPC xenografts suggest that these agents offer considerable promise as new therapeutics for patients with CRPC and those resistant to current therapy.

Topics: Androstadienes; Animals; Antineoplastic Agents; Apoptosis; Benzimidazoles; Cell Line, Tumor; Cell Survival; Cytochromes c; Humans; Male; Mice; Mice, SCID; Neoplasm Transplantation; Phosphorylation; Poly(ADP-ribose) Polymerases; Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; Proteasome Endopeptidase Complex; Protein Isoforms; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-mdm2; Receptors, Androgen; RNA, Small Interfering

Loss of DAB2IP, a novel tumor suppressor gene, is associated with the high risk of aggressive prostate cancer (PCa). Previously, we reported that DAB2IP modulated androgen receptor activation in the development of castration-resistant PCa; however, its direct action on the failure of androgen deprivation therapy (ADT) remains largely unknown. In this study, we showed that DAB2IP knockdown could significantly enhance in vitro growth and colony formation of PCa cells following ADT as well as tumorigenicity in pre-castrated nude mice. In addition, DAB2IP loss stabilized mitochondrial transmembrane potential, prevented release of cytochrome c, Omi/HtrA2 and Smac from the mitochondria to the cytoplasm and inhibited intrinsic apoptosis induced by ADT. Mechanistically, DAB2IP could interact with the signal transducer and activator of transcription 3 (STAT3) via its unique PR domain and suppress STAT3 phosphorylation and transactivation, leading to the inhibition of survivin expression in PCa cells. Moreover, the luminal epithelia in DAB2IP(-/-) mice with more activated STAT3 and survivin expression were resistant to castration-induced apoptosis. Consistently, DAB2IP expression inversely correlated with STAT3 phosphorylation and survivin expression in PCa patients. Together, our data indicate that DAB2IP loss reprograms intracellular signal transduction and anti-apoptotic gene expression, which potentiates PCa cell survival from ADT-induced cell death.

Topics: Animals; Apoptosis; Castration; Cytochromes c; Gene Deletion; HEK293 Cells; Humans; Inhibitor of Apoptosis Proteins; Male; Membrane Potential, Mitochondrial; Mice; Mice, Nude; Phosphorylation; Prostatic Neoplasms, Castration-Resistant; ras GTPase-Activating Proteins; Repressor Proteins; Signal Transduction; STAT3 Transcription Factor; Survivin