Sivanantham Banudevi

Induction of apoptosis in human breast cancer cells by nimbolide through extrinsic and intrinsic pathway.

We aimed to investigate the cytotoxic effects of nimbolide, a limonoid present in leaves and flowers of the neem tree (Azadirachta indica) on human breast cancer cells. The molecular mechanisms involved in the apoptotic activity exerted by nimbolide were studied on the estrogen dependent (MCF-7) and estrogen independent (MDA-MB-231) human breast cancer cell lines. The growth inhibitory effect of nimbolide was assessed by MTT assay. Apoptosis induction by nimbolide treatment was determined by JC-1 mitochondrial membrane potential staining, cytochrome c release, caspase activation, cleavage of PARP and AO/EtBr dual staining. The modulation of apoptotic proteins (intrinsic pathway: Bax, bad, Bcl-2, Bcl-xL, Mcl-1, XIAP-1 and caspase-3, 9; extrinsic pathway: TRAIL, FasL, FADDR and Caspase-8) were studied by western blot and real time PCR analysis. Treatment with nimbolide resulted in dose and time-dependent inhibition of growth of MCF-7 and MDA-MB-231 cells. The occurrence of apoptosis in these cells was indicated by JC-1 staining, modulation of both intrinsic and extrinsic apoptotic signaling molecules expression and further apoptosis was confirmed by AO/EtBr dual staining. These events were associated with: increased levels of proapoptotic proteins Bax, Bad, Fas-L, TRAIL, FADDR, cytochrome c and reduced levels of the anti-apoptotic proteins Bcl-2, Bcl-xL, Mcl-1 and XIAP-1. Nimbolide induces the cleavage of pro-caspase-8, pro-caspase-3 and PARP. The above data suggest that nimbolide induces apoptosis by both the intrinsic and extrinsic pathways. With evidence of above data it is suggested that nimbolide exhibit anticancer effect through its apoptosis-inducing property. Thus, nimbolide raises new hope for its use in anticancer therapy.

Quercetin inhibits invasion, migration and signalling molecules involved in cell survival and proliferation of prostate cancer cell line (PC-3)

Urokinase‐type plasminogen activator (uPA) is a serine protease that is involved in cancer progression, especially invasion and metastasis including prostate cancer. uPA activation is mediated by transactivation of uPAR and epidermal growth factor receptor (EGF‐R) in prostate cancer progression. Prostate cancer (PC‐3) cells have highly invasive capacity and they express uPA and uPAR gene. PC‐3 cells are treated with quercetin, which inhibits invasion and migration of PC‐3 cells. Quercetin downregulates uPA, uPAR and EGF, EGF‐R mRNA expressions. Quercetin inhibits cell survival factor β‐catenin, NF‐κB and also proliferative signalling molecules such as p‐EGF‐R, N‐Ras, Raf‐1, c.Fos c.Jun and p‐c.Jun protein expressions. But quercetin increased p38 mitogen‐activated protein kinase protein expression. Our results suggest that quercetin inhibit migration and invasion of prostate cancer cells. It shows the value for treatment of invasive and metastasis type of prostate cancer. Copyright

Quercetin regulates insulin like growth factor signaling and induces intrinsic and extrinsic pathway mediated apoptosis in androgen independent prostate cancer cells (PC-3)

Progression of prostate cancer is facilitated by growth factors that activate critical signaling cascades thereby promote prostate cancer cell growth, survival, and migration. To investigate the effect of quercetin on insulin-like growth factor signaling and apoptosis in androgen independent prostate cancer cells (PC-3), IGF-IR, PI-3K, p-Akt, Akt, cyclin D1, Bad, cytochrome c, PARP, caspases-9 and 10 protein levels were assessed by western blot analysis. Mitochondrial membrane potency was detected by rhodamine-123 staining. Quercetin induced caspase-3 activity assay was performed for activation of apoptosis. Further, RT-PCR was also performed for Bad, IGF-I, II, IR, and IGFBP-3 mRNA expression. Quercetin significantly increases the proapoptotic mRNA levels of Bad, IGFBP-3 and protein levels of Bad, cytochrome C, cleaved caspase-9, caspase-10, cleaved PARP and caspase-3 activity in PC-3 cells. IGF-IRβ, PI3K, p-Akt, and cyclin D1 protein expression and mRNA levels of IGF-I, II and IGF-IR were decreased significantly. Further, treatment with PI3K inhibitor (LY294002) and quercetin showed decreased p-Akt levels. Apoptosis is confirmed by loss of mitochondrial membrane potential in quercetin treated PC-3 cells. This study suggests that quercetin decreases the survival of androgen independent prostate cancer cells by modulating the expression of insulin-like growth factors (IGF) system components, signaling molecules and induces apoptosis, which could be very useful for the androgen independent prostate cancer treatment.

Effect of diallyl disulfide on insulin-like growth factor signaling molecules involved in cell survival and proliferation of human prostate cancer cells in vitro and in silico approach through docking analysis

PURPOSE Diallyl Disulfide (DADS) is one of the major components of garlic, which inhibits the proliferation of various cancer cells. Our previous studies showed that DADS inhibits cell growth and induces apoptosis on prostate cancer cells. Insulin like growth factor signaling pathway plays a significant role on prostate cancer cell growth and survival and its over expression also identified in human prostate cancers. The molecular mechanism of IGF mediated PI3K/Akt signaling remains to be elucidated. The present study was designed to evaluate the effects of diallyl disulfide on IGF signaling in androgen independent prostate cancer cells (PC-3). METHODS DADS (10-50 μM) caused dose-dependent inhibition of PC-3 cells, were analyzed by MTT, IC50 value of PC-3 cells was 40 μM for 24h. Interestingly, DADS also altered the mRNA and protein expressions of IGF signaling and apoptotic molecules which were confirmed by semi quantitative PCR and western blot method. Further the docking study of DADS with IGF receptor was carried out by Ligand Fit of Discovery studio. Accord Excel Package was used for the prediction of ADME properties of the compound. RESULTS The results suggests that DADS decreases the survival rate of androgen independent prostate cancer cells by modulating the expression of IGF system, which leads to inhibition of phosphorylation of Akt, thereby inhibits cell cycle progression and survival by lowering the expression of cyclin D1, NFkB and anti-apoptotic Bcl-2 molecule and increasing the level of pro-apoptotic (Bad and Bax) signaling molecules which leads to apoptosis. CONCLUSION The present investigation showed downregulation of Akt and a concomitant increase in apoptosis in DADS treated prostate cancer cells. Since inhibition of this Akt pathway by DADS leads to inhibition in cancer cell progression, it is highly suggested that DADS has the potential use as a therapy for prostate cancer.

Protective effect of zinc on N-methyl-N-nitrosourea and testosterone-induced prostatic intraepithelial neoplasia in the dorsolateral prostate of Sprague Dawley rats

Previous studies have suggested that zinc exerts anticarcinogenic and antiproliferative effects against prostate cancer both in vitro and in rat ventral prostate. Zinc accumulation diminishes early in the course of prostate malignancy and it inhibits the growth of several carcinoma cells through induction of cell cycle arrest and apoptosis. In this study, we have investigated the influence of zinc on N-methyl-N-nitrosourea (MNU) and testosterone (T)-induced prostatic intraepithelial neoplasia in the dorsolateral prostate of Sprague Dawley (SD) rats. The results indicate that zinc plays an important role in prostate carcinogenesis. Increased tumor incidence was accompanied by a decrease in prostatic acid phosphatase activity, citrate, zinc, glutathione-S-transferase, reduced glutathione, p53, B-cell lymphoma protein (Bcl-2)-associated X protein and caspase-3 levels in MNU + T-treated rats. On the contrary, significantly increased phase I drug metabolizing enzyme activities, lipid peroxide, hydrogen peroxide, proliferating cell nuclear antigen, Bcl-2 and Bcl-XL protein levels were observed in the dorsolateral prostate of MNU + T-treated rats. Simultaneous zinc supplementation significantly reversed these effects in MNU + T-treated rats. Signs of dysplasia, a characteristic of prostatic intraepithelial neoplasia, were evident in the dorsolateral prostatic tissue sections by MNU + T administration. However, zinc supplementation has reversed these effects in the dorsolateral prostatic histoarchitecture. These results suggest that zinc may act as an essential trace element against MNU and testosterone-induced prostatic preneoplastic progression in SD rats.