Lucanthone, Autophagy Inhibitor, Enhances the Apoptotic Effects of TRAIL through miR-216a-5p-Mediated DR5 Upregulation and DUB3-Mediated Mcl-1 Downregulation

A lucanthone, one of the family of thioxanthenones, has been reported for its inhibitory effects of apurinic endonuclease-1 and autophagy. In this study, we investigated whether lucanthone could enhance tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in various cancer cells. Combined treatment with lucanthone and TRAIL significantly induced apoptosis in human renal carcinoma (Caki and ACHN), prostate carcinoma (PC3), and lung carcinoma (A549) cells. However, combined treatment did not induce apoptosis in normal mouse kidney cells (TCMK-1) and normal human skin fibroblast (HSF). Lucanthone downregulated protein expression of deubiquitinase DUB3, and a decreased expression level of DUB3 markedly led to enhance TRAIL-induced apoptosis. Ectopic expression of DUB3 inhibited combined treatment with lucanthone and TRAIL-induced apoptosis. Moreover, lucanthone increased expression level of DR5 mRNA via downregulation of miR-216a-5p. Transfection of miR-216a-5p mimics suppressed the lucanthone-induced DR5 upregulation. Taken together, these results provide the first evidence that lucanthone enhances TRAIL-induced apoptosis through DR5 upregulation by downregulation of miR-216a-5p and DUB3-dependent Mcl-1 downregulation in human renal carcinoma cells.

In-vitro antioxidant and selective cytotoxicity of Garcinia cambogia and Garcinia indica leaf extracts on human kidney cancer cell line

Kidney cancer is one among the top 10 cancers. Renal cell carcinoma (RCC) is commonly known kidney cancer. Almost all clinically targeted drugs used in treating RCC have many aftereffects. To overcome this problem with herbal products, the present study is aimed to investigate the preliminary phytochemicals, antioxidants and selective cytotoxicity of aqueous leaves extract of Garcinia cambogia (GC)and Garcinia indica (GI)on(HEK-293) human embryonic kidney cells and (A498)human renal carcinoma cells. The phytochemical analyses were done using standard protocols. In-vitro antioxidant activity was carried out using DPPH, FRAP, and Phosphomolybdenum assay. Anticancer activity on A498 kidney cancer cell line was evaluated by MTT assay and the selectivity index was calculated. Preliminary phytochemical analysis of GC and GI leaf extract divulged the presence of various phyto-constituents. GI extract revealed higher phenolic content while flavonoid content was more in GC extract compared to alkaloids and saponins. Both plant extracts exhibited higher antioxidant capacities based on the test performed.GC and GIleaf extract wasselectively cytotoxic in-vitro to (A498) human renal carcinoma cells and can be safely used against kidney cancer at 500 µM (GC extract)and 300 µM (GI extract). Selective index for GC and GI extract was15.9 and 2.4respectively. The results indicate that GC and GI extracts are a favourable antioxidant and anti-cancer agents for A498 human renal carcinoma cells. However, further studies to isolate the bioactive compounds responsible for these activities are underway and to explore their molecular mechanism.

Cyclin-Dependent Kinase Inhibitor BMI-1026 Induces Apoptosis by Downregulating Mcl-1 (L) and c-FLIP (L) and Inactivating p-Akt in Human Renal Carcinoma Cells

Previous studies have investigated the inhibitory effect of BMI-1026 on cyclin-dependent kinase 1 in vitro. However, the molecular mechanisms by which BMI-1026 treatment leads to cancer cell death remain unclear. This study was conducted to investigate the anticancer mechanisms of BMI-1026 on human renal carcinoma Caki cells. BMI-1026 induced apoptosis in association with the cleavage of poly(ADP-ribose) polymerase and pro-caspase-3 and the release of apoptosis-inducing factor and cytochrome c from mitochondria in Caki cells. BMI-1026-induced apoptosis was inhibited by the pan-caspase inhibitor z-VAD-fmk. Furthermore, BMI-1026 downregulated Bcl-2 and X-linked inhibitor of apoptosis protein (XIAP) at the transcriptional level and Mcl-1 (L) and cellular FADD-like IL-1β-converting enzyme inhibitory protein (c-FLIP (L)) at the post-transcriptional level. Interestingly, Mcl-1 (L) and c-FLIP (L), but not Bcl-2 or XIAP, played important roles in BMI-1026-induced Caki cell apoptosis. Although the constitutively active form of Akt did not attenuate BMI-1026-induced apoptosis, blockade of the PI3K/Akt pathway using a subcytotoxic concentration of the PI3K/Akt inhibitor LY294002 enhanced Caki cell apoptosis induced by BMI-1026. Electrophysiological safety was confirmed by determining the cardiotoxicity of BMI-1026 via left ventricular pressure analysis. These results suggest that BMI-1026 is a potent multitarget anticancer agent with electrophysiological safety and should be further investigated.

A nitric oxide-releasing prodrug promotes apoptosis in human renal carcinoma cells: Involvement of reactive oxygen species

Background JS-K is a nitric oxide (NO)-releasing prodrug of the O2-arylated diazeniumdiolate group that shows pronounced cytotoxicity and antitumor properties in numerous cancer models, including in vitro as well as in vivo. Reactive oxygen species (ROS) induce carcinogenesis by altering the redox status, causing increment in vulnerability to oxidative stress. Material and methods To determine the effect of JS-K, a glutathione S-transferase (GST)-activated NO-donor prodrug, on the induction of ROS accumulation, proliferation, and apoptosis in human renal carcinoma cells, we measured the changes of cell proliferation, apoptosis, ROS growth, and initiation of the mitochondrial signaling pathway before and after JS-K treatment. Results In vitro, dose- and time-dependent development of renal carcinoma cells were controlled for JS-K, and JS-K also triggered ROS aggregation and cell apoptosis. Treatment with JS-K induces the levels of pro-apoptotic proteins (Bak and Bax) and decrease the number of anti-apoptotic protein (Bcl-2). In fact, JS-K-induced apoptosis was reversed by the antioxidant N-acetylcysteine, and oxidized glutathione, a pro-oxidant, improved JS-K-induced apoptosis. Finally, we demonstrated that in renal carcinoma cells, JS-K improved the chemosensitivity of doxorubicin. Conclusion Our data indicate that JS-K-released NO induce apoptosis of renal carcinoma cells by increasing ROS levels.