Isorhapontigenin (ISO) is a new derivative of stilbene compound that was isolated from the Chinese herb Gnetum Cleistostachyum, and has been used for treatment of bladder cancers for centuries. In our current studies, we have explored the potential inhibitory effect and molecular mechanisms underlying ISO anti-cancer effects on anchorage-independent growth of human bladder cancer cell lines. We found that ISO showed a significant inhibitory effect on human bladder cancer cell growth and was accompanied with related cell cycle G0/G1 arrest as well as downregulation of Cyclin D1 expression at the transcriptional level in UMUC3 and RT112 cells. Further studies identified that ISO down-regulated Cyclin D1 gene transcription via inhibition of SP1 transactivation. Moreover, ectopic expression of GFP-Cyclin D1 rendered UMUC3 cells resistant to induction of cell cycle G0/G1 arrest and inhibition of cancer cell anchorage-independent growth by ISO treatment. Together, our studies demonstrate that ISO is an active compound that mediates for Gnetum Cleistostachyum’s induction of cell cycle G0/G1 arrest and inhibition of cancer cell anchorage-independent growth through down-regulating SP1/Cyclin D1 axis in bladder cancer cells. Our studies provide a novel insight into understanding the anti-cancer activity of the Chinese herb Gnetum Cleistostachyum and its isolate ISO.

Aim: To appraise the efficacy of Vam3 (Amurensis H), a dimeric derivative of resveratrol, at inhibiting cigarette smoke-induced autophagy. Methods: Human bronchial epithelial cells were treated with cigarette smoke condensates, and a chronic obstructive pulmonary disease (COPD) model was established by exposing male BALB/c mice to cigarette smoke. The protein levels of the autophagic marker microtubule-associated protein 1A/1B-light chain 3 (LC3), Sirtuin 1 (Sirt1), and foxhead box O 3a (FoxO3a) were examined using Western blotting and Immunohistochemistry. LC3 punctae were detected by immunofluorescence. The levels of FoxO3a acetylation were examined by immunoprecipitation. The level of intracellular oxidation was assessed by detecting ROS and GSH-Px. Results: Vam3 attenuated cigarette smoke condensate-induced autophagy in human bronchial epithelial cells, and restored the expression levels of Sirt1 and FoxO3a that had been reduced by cigarette smoke condensates. Similar protective effects of Vam3, reducing autophagy and restoring the levels of Sirt1 and FoxO3a, were observed in the COPD animal model. Additionally, Vam3 also diminished the oxidative stress that was induced by the cigarette smoke condensates. Conclusion: Vam3 decreases cigarette smoke-induced autophagy via up-regulating/restoring the levels of Sirt1 and FoxO3a and inhibiting the induced oxidative stress.

No abstract