Statin Use in Prostate Cancer: An Update

3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, known as statins, are commonly prescribed for the treatment of hypercholesterolemia and cardiovascular disease. A systematic review was conducted using the keywords “statin and prostate cancer” within the title search engines including PubMed, Web of Science, and the Cochrane Library for relevant research work published between 2004 and December 2015. Although still premature, accumulating clinical evidence suggests that statin use may be beneficial in the prevention and/or treatment of prostate cancer. These human studies consist of meta-analyses of secondary endpoints obtained from randomized, controlled cardiovascular disease clinical trials of statins, patient database, observational studies, and a few, small case–control studies, directly addressing statin use on prostate cancer pathology and recurrence. This review summarizes and discusses the recent clinical literature on statins and prostate cancer with a recommendation to move forward with randomized, placebo-controlled clinical trials, investigating the use of statins. Additional preclinical testing of statins on prostate cancer cell lines and in vivo models is needed to elucidate pathways and determine its efficacy for prevention and/or treatment of prostate cancer, more specifically, the difference in the effectiveness of lipophilic versus hydrophilic statins in prostate cancer

Green tea polyphenols induce p53-dependent and p53-independent apoptosis in prostate cancer cells through two distinct mechanisms.

Inactivation of the tumor suppressor gene p53 is commonly observed in human prostate cancer and is associated with therapeutic resistance. We have previously demonstrated that green tea polyphenols (GTP) induce apoptosis in prostate cancer cells irrespective of p53 status. However, the molecular mechanisms underlying these observations remain elusive. Here we investigated the mechanisms of GTP-induced apoptosis in human prostate cancer LNCaP cells stably-transfected with short hairpin-RNA against p53 (LNCaPshp53) and control vector (LNCaPshV). GTP treatment induced p53 stabilization and activation of downstream targets p21/waf1 and Bax in a dose-dependent manner specifically in LNCaPshV cells. However, GTP-induced FAS upregulation through activation of c-jun-N-terminal kinase resulted in FADD phosphorylation, caspase-8 activation and truncation of BID, leading to apoptosis in both LNCaPshV and LNCaPshp53 cells. In parallel, treatment of cells with GTP resulted in inhibition of survival pathway, mediated by Akt deactivation and loss of BAD phosphorylation more prominently in LNCaPshp53 cells. These distinct routes of cell death converged to a common pathway, leading to loss of mitochondrial transmembrane potential, cytochrome c release and activation of terminal caspases, resulting in PARP-cleavage. GTP-induced apoptosis was attenuated with JNK inhibitor, SP600125 in both cell lines; whereas PI3K-Akt inhibitor, LY294002 resulted in increased cell death prominently in LNCaPshp53 cells, establishing the role of two distinct pathways of GTP-mediated apoptosis. Furthermore, GTP exposure resulted in inhibition of class I HDAC protein, accumulation of acetylated histone-H3 in total cellular chromatin, resulting in increased accessibility of transcription factors to bind with the promoter sequences of p21/waf1 and Bax, regardless of the p53 status of cells, consistent with effects elicited by an HDAC inhibitor, trichostatin A. These results demonstrate that GTP induces prostate cancer cell death by two distinct mechanisms regardless of p53 status, thus identifying specific well-defined molecular mechanisms that may be targeted by chemopreventive and/or therapeutic strategies

Green tea polyphenols induce apoptosis irrespective of p53 status in prostate cancer LNCaPshV and LNCaPshp53 cells.

<p>[<b>A</b>] Cells were treated with 20–80 µg/ml concentration of GTP for 24 h and Western blotting was performed for p53, Akt, p-Akt (Ser473), BAD, p-BAD (Ser136), p21/waf1, PUMA and Bax proteins. [<b>B</b>] Cells were treated with 40 µg/ml concentration of GTP for 3, 6, 9, 12, 24 and 48 h and Western blotting was performed for procaspase-9, cleaved caspase-9 and cleaved caspase-3 proteins. A typical actin blot demonstrates internal loading control. Cytochrome c release from mitochondria to cytosol was determined by Western blotting in GTP treated cells. A typical actin blot demonstrates internal loading control for cytosol whereas VDAC as internal loading control for mitochondria. [<b>D</b>] Cells were treated with 20 µM concentration of PI3K-Akt inhibitor LY294002 for 8 h and with 40 µg/ml GTP for 16 h alone, or LY294002 for 8 h followed by GTP treatment in combination followed by Western blotting for p-Akt, Akt, p-BAD and BAD proteins. The expressions of native proteins were considered as loading controls. [<b>D</b>] Cell death measurement was performed by photometric enzyme immunoassay Cell Death Detection ELISA kit. The bars represent mean±SD of at least two independent experiments each performed in duplicate, **<i>p</i><0.001 represents significant differences as compared to control group. [<b>E</b>] Light microscopic images of LNCaPshV and LNCaPshp53 cells treated with LY294002 and GTP alone or in combination. The details are described in the materials and methods section.</p

Camptothecin induces differential apoptosis in LNCaPshV and LNCaPshp53 cells.

<p>Isogenic cells with lenti-virus vector background were generated by permanent knockdown of p53 in LNCaP cells [LNCaPshp53] and transfected with control vector, LNCaPshV cells. [<b>A</b>] Cell treated with 50 and 100 ng/ml camptothecin for 24 h were harvested, stained with PI and analyzed by flow cytometry to measure sub-G1 and G1 population. [<b>B</b>] Cells were treated with 50, 100 and 200 ng/ml of camptothecin for 24 h and stained with methylene blue. The intensity of methylene blue taken up by live cells was measured spectrophotometerically after eluting the dye in 0.1N HCl and compared with untreated cells. [<b>C</b>] Knockdown of p53 upregulated Akt/BAD signaling in prostate cancer cells. LNCaPshV and LNCaPshp53 cells were lysed and Western blotting was performed for p53, Akt, p-Akt (Ser473), BAD, p-BAD (Ser136) proteins. Actin was used as internal loading control. [<b>D</b>] Relative intensities of p-Akt and p-Bad protein in LNCaPshV and LNCaPshp53RNA cells where bands were normalized to actin and expressed in relative values compared to the native protein. The details are described in the materials and methods section.</p

Green tea polyphenols-mediated apoptosis induced by death receptor pathway in prostate cancer LNCaPshV and LNCaPshp53 cells.

<p>[<b>A</b>] Cells were treated with 40 µg/ml concentration of GTP for 1, 5, 10, 15, 30 and 60 min and Western blotting was performed for SAPK/JNK, p-JNK, FAS, FADD, p-FADD, BID and t-BID proteins. A typical actin blot demonstrates internal loading control. [<b>B</b>] Cells were treated with 40 µg/ml concentration of GTP for 3, 6, 9, 12, 24 and 48 h and Western blotting was performed for cleaved PARP, procaspase-8, cleaved caspase-8, c-IAP and XIAP proteins. A typical actin blot demonstrates internal loading control. [<b>C</b>] Cells were treated with 20 µM concentration of JNK inhibitor SP600125 for 8 h and with 40 µg/ml GTP for 16 h alone, or SP600125 for 8 h followed by GTP treatment in combination followed by Western blotting for JNK, p-JNK, FAS and p-FADD proteins. The expression of native JNK protein was considered as loading control. [<b>D</b>] Cell death measurement was performed by photometric enzyme immunoassay Cell Death Detection ELISA kit. The bars represent mean±SD of at least two independent experiments each performed in duplicate, **<i>p</i><0.001 represents significant differences as compared to control group. [<b>E</b>] Light microscopic images of LNCaPshV and LNCaPshp53 cells treated with SP600125 and GTP alone or in combination. The details are described in the materials and methods section.</p

Green tea polyphenols decrease cell viability and induces apoptosis in LNCaPshV and LNCaPshp53 cells.

<p>[<b>A</b>] Cells were exposed to 20–80 µg/ml concentration of GTP for 24 h, and viability of the cells was determined by the MTT assay. Cell viabilities are depicted as percentages; vehicle-treated cells were regarded as 100% viable. The bars represent mean±SD of at least two independent experiments each performed in duplicate, **<i>p</i><0.001 represents significant differences as compared to control group without GTP treatment. [<b>B</b>] Cell were treated with 40 µg/ml GTP for 24, 48, 72 and 96 h and distribution of cells were recorded in different stages of cell cycle analyzed using FACS analysis. [<b>C</b>] Cells were treated with 40 and 80 µg/ml GTP for 96 h and the number of cells undergoing apoptosis were determined by measuring cell population in sub G1 phase of the cell cycle. The bars represent mean±SD of at least two independent experiments each performed in duplicate, **<i>p</i><0.001 represents significant differences as compared to control group without GTP treatment. [<b>D</b>] Light microscopic images of LNCaPshV and LNCaPshp53 cells treated with 40 and 80 µg/ml GTP for 96 h. GTP treatment exhibits morphological changes consistent with apoptosis in both these cells. [<b>E</b>] DNA fragmentation assay. The cells were treated with 40 µg/ml concentration of GTP for 48 h, collected for DNA isolation and subjected to agarose gel electrophoresis, followed by visualization of bands under UV light. The details are described in the materials and methods section.</p

Efficacy of checkpoint inhibition after CAR-T failure in aggressive B-cell lymphomas: Outcomes from 15 U.S. institutions

Checkpoint inhibitor (CPI) therapy with anti-PD-1 antibodies has been associated with mixed outcomes in small cohorts of aggressive B-cell lymphoma patients following CAR T-cell therapy failure. To more definitively define CPI therapy efficacy in this population, we retrospectively evaluated clinical outcomes in a large cohort of 96 patients with aggressive B-cell lymphomas receiving CPI therapy after CAR-T failure across 15 U.S. academic centers. Most patients (53%) had DLBCL, were treated with axicabtagene ciloleucel (53%), relapsed early (≤180 days) after CAR-T (83%), and received pembrolizumab (49%) or nivolumab (43%). CPI therapy was associated with an overall response rate of 19% and a complete response rate of 10%. Median duration of response was 221 days. Median progression-free survival (PFS) and overall survival (OS) were 54 and 159 days, respectively. Outcomes to CPI therapy were significantly improved in patients with primary mediastinal B-cell lymphoma. PFS (128 versus 51 days) and OS (387 versus 131 days) were significantly longer in patients with late (>180 days) versus early (≤180 days) relapse after CAR-T. Grade ≥3 adverse events occurred in 19% of CPI-treated patients. Most patients (83%) died, commonly due to progressive disease. Only 5% had durable responses to CPI therapy. In the largest cohort of aggressive B-cell lymphoma patients treated with CPI therapy after CAR-T relapse, our results reveal poor outcomes, particularly among those relapsing early after CAR-T. In conclusion, CPI therapy is not an effective salvage strategy for most patients after CAR-T, where alternative approaches are needed to improve post-CAR-T outcomes