14-o-phosphonooxymethyltriptolide and Lung-Neoplasms

Minnelide/Triptolide (TL) has recently emerged as a potent anticancer drug in non-small cell lung cancer (NSCLC). However, the precise mechanism of its action remains ambiguous. In this study, we elucidated the molecular basis for TL-induced cell death in context to p53 status. Cell death was attributed to dysfunction of mitochondrial bioenergetics in p53-deficient cells, which was characterized by decreased mitochondrial respiration, steady-state ATP level and membrane potential, but augmented reactive oxygen species (ROS). Increased ROS production resulted in oxidative stress in TL-treated cells. This was exhibited by elevated nuclear levels of a redox-sensitive transcriptional factor, NF-E2-related factor-2 (NRF2), along with diminished cellular glutathione (GSH) content. We further demonstrated that in the absence of p53, TL blunted the expression of mitochondrial SIRT3 triggering increased acetylation of NDUAF9 and succinate dehydrogenase, components of complexes I and II of the electron transport chain (ETC). TL-mediated hyperacetylation of complexes I and II proteins and these complexes displayed decreased enzymatic activities. We also provide the evidence that P53 regulate steady-state level of SIRT3 through Proteasome-Pathway. Finally, forced overexpression of Sirt3, but not deacetylase-deficient mutant of Sirt3 (H243Y), restored the deleterious effect of TL on p53-deficient cells by rescuing mitochondrial bioenergetics. On contrary, Sirt3 deficiency in the background of wild-type p53 triggered TL-induced mitochondrial impairment that echoed TL effect in p53-deficeint cells. These findings illustrate a novel mechanism by which TL exerts its potent effects on mitochondrial function and ultimately the viability of NSCLC tumor.

Topics: Acetylation; Antineoplastic Agents, Alkylating; Apoptosis; Carcinoma, Non-Small-Cell Lung; Diterpenes; Epoxy Compounds; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Membrane Potential, Mitochondrial; Mitochondria; Organophosphates; Oxidative Stress; Phenanthrenes; Reactive Oxygen Species; RNA, Small Interfering; Sirtuin 3; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Osteosarcoma is the most common bone cancer in children and adolescents with a 5-year survival rate of about 70%. In this study, we have evaluated the preclinical therapeutic efficacy of the novel synthetic drug, Minnelide, a prodrug of triptolide on osteosarcoma. Triptolide was effective in significantly inducing apoptosis in all osteosarcoma cell lines tested but had no significant effect on the human osteoblast cells. Notably, Minnelide treatment significantly reduced tumor burden and lung metastasis in the orthotopic and lung colonization models. Triptolide/Minnelide effectively downregulated the levels of pro-survival proteins such as heat shock proteins, cMYC, survivin and targets the NF-κB pathway.

Topics: Animals; Antineoplastic Agents, Alkylating; Apoptosis; Caspase 3; Caspase 7; Caspase 9; Cell Line, Tumor; Cell Survival; Diterpenes; Down-Regulation; Epoxy Compounds; Female; Gene Expression Regulation, Neoplastic; Heat-Shock Proteins; Humans; Inhibitor of Apoptosis Proteins; Lung Neoplasms; Mice; Mice, Nude; Neoplasm Transplantation; NF-kappa B; Organophosphates; Osteoblasts; Osteosarcoma; Phenanthrenes; Proto-Oncogene Proteins c-myc; Survivin; Tumor Burden; Xenograft Model Antitumor Assays

Minnelide, a pro-drug of triptolide, has recently emerged as a potent anticancer agent. The precise mechanisms of its cytotoxic effects remain unclear.. Cell viability was studied using CCK8 assay. Cell proliferation was measured real-time on cultured cells using Electric Cell Substrate Impedence Sensing (ECIS). Apoptosis was assayed by Caspase activity on cultured lung cancer cells and TUNEL staining on tissue sections. Expression of pro-survival and anti-apoptotic genes (HSP70, BIRC5, BIRC4, BIRC2, UACA, APAF-1) was estimated by qRTPCR. Effect of Minnelide on proliferative cells in the tissue was estimated by Ki-67 staining of animal tissue sections.. In this study, we investigated in vitro and in vivo antitumor effects of triptolide/Minnelide in non-small cell lung carcinoma (NSCLC). Triptolide/Minnelide exhibited anti-proliferative effects and induced apoptosis in NSCLC cell lines and NSCLC mouse models. Triptolide/Minnelide significantly down-regulated the expression of pro-survival and anti-apoptotic genes (HSP70, BIRC5, BIRC4, BIRC2, UACA) and up-regulated pro-apoptotic APAF-1 gene, in part, via attenuating the NF-κB signaling activity.. In conclusion, our results provide supporting mechanistic evidence for Minnelide as a potential in NSCLC.

Topics: Animals; Antineoplastic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Cell Survival; Diterpenes; Epoxy Compounds; Lung Neoplasms; Mice; NF-kappa B; Organophosphates; Phenanthrenes; Signal Transduction; Transcription, Genetic; Transcriptional Activation; Up-Regulation; Xenograft Model Antitumor Assays