BACKGROUND: Taxol is the most commonly used agent for salvage chemotherapy in transitional cell carcinoma of the urothelium. We examined mechanisms responsible for taxol resistance by using T24 human bladder carcinoma cells. MATERIALS AND METHODS: We used an inhibitor and an activator of the phosphatidylinositol-3 kinase-Akt pathway in cell survival and caspase-3 assays, an HPLC method for determining released cytochrome c and immunoblotting for detecting protein phosphorylation. RESULTS: Activation of Akt increased paclitaxel resistance by increasing Bad phosphorylation, leading to decreased release of mitochondrial cytochrome c and caspase-3-mediated apoptosis. On the other hand, inhibition of Akt prevented paclitaxel resistance by enhancing the effects of paclitaxel on Bad phosphorylation, mitochondrial cytochrome c release and caspase-3-mediated apoptosis, besides diminishing or abolishing the opposing effects of Akt activation. CONCLUSION: Akt-mediated Bad phosphorylation plays an important role in preservation of mitochondrial membrane systems leading to paclitaxel resistance in T24 cells.
BACKGROUND:Taxol is the most commonly used agent for salvage chemotherapy in transitional cell carcinoma of the urothelium. We examined mechanisms responsible for taxol resistance by using T24 humanbladder carcinoma cells. MATERIALS AND METHODS: We used an inhibitor and an activator of the phosphatidylinositol-3 kinase-Akt pathway in cell survival and caspase-3 assays, an HPLC method for determining released cytochrome c and immunoblotting for detecting protein phosphorylation. RESULTS: Activation of Akt increased paclitaxel resistance by increasing Bad phosphorylation, leading to decreased release of mitochondrial cytochrome c and caspase-3-mediated apoptosis. On the other hand, inhibition of Akt prevented paclitaxel resistance by enhancing the effects of paclitaxel on Bad phosphorylation, mitochondrial cytochrome c release and caspase-3-mediated apoptosis, besides diminishing or abolishing the opposing effects of Akt activation. CONCLUSION:Akt-mediated Bad phosphorylation plays an important role in preservation of mitochondrial membrane systems leading to paclitaxel resistance in T24 cells.
Authors: Hye Sook Chon; Douglas C Marchion; Yin Xiong; Ning Chen; Elona Bicaku; Xiaomang Ba Stickles; Nadim Bou Zgheib; Patricia L Judson; Ardeshir Hakam; Jesus Gonzalez-Bosquet; Robert M Wenham; Sachin M Apte; Johnathan M Lancaster Journal: Gynecol Oncol Date: 2011-10-26 Impact factor: 5.482
Authors: Moureq R Alotaibi; Zeinab K Hassan; Salim S Al-Rejaie; Musaad A Alshammari; Mashal M Almutairi; Ali R Alhoshani; Wael A Alanazi; Mohamed M Hafez; Othman A Al-Shabanah Journal: Asian Pac J Cancer Prev Date: 2018-03-27