Mechanistic rationale for MCL1 inhibition during androgen deprivation therapy.

Androgen deprivation therapy induces apoptosis or cell cycle arrest in prostate cancer (PCa) cells. Here we set out to analyze whether MCL1, a known mediator of chemotherapy resistance regulates the cellular response to androgen withdrawal. Analysis of MCL1 protein and mRNA expression in PCa tissue and primary cell culture specimens of luminal and basal origin, respectively, reveals higher expression in cancerous tissue compared to benign origin.

Enhanced inhibition of prostate tumor growth by dual targeting the androgen receptor and the regulatory subunit type iα of protein kinase a in vivo.

Progression to castration resistance is a major problem in the treatment of advanced prostate cancer and is likely to be driven by activation of several molecular pathways, including androgen receptor (AR) and cyclic AMP-dependent protein kinase A (PKA). In this study, we examined the therapeutic efficacy of a combined inhibition of the AR and the regulatory subunit type Iα (RIα) of protein kinase A with second generation antisense oligonucleotides (ODNs) in androgen-sensitive LNCaP and castration-resistant LNCaPabl tumors in vivo. We found that targeting the AR alone inhibited LNCaP, as well as LNCaPabl tumors.

Lovastatin causes diminished PSA secretion by inhibiting AR expression and function in LNCaP prostate cancer cells.

Objectives: To investigate why statin users display a noticeable decline in prostate specific antigen (PSA) as revealed in recent clinical trials, we tested the effects of lovastatin on the androgen signaling cascade in lymph node carcinoma of the prostate (LNCaP) prostate cancer cells.

Methods: Effects of lovastatin alone or in combination with a small interference RNA to inhibit AR expression on cell proliferation and induction of apoptosis were assessed by [(3)H] thymidine incorporation and caspase-3 activity assay. PSA levels were measured in the cell culture supernatant by immunoassay.