Background: Ailanthone (Aila) is a natural active compound isolated from the Ailanthus altissima, which has been shown to possess an "in vitro" growth-inhibitory effect against several cancer cell lines. Advanced bladder cancer is a common disease characterized by a frequent onset of resistance to cisplatin-based therapy. The cisplatin (CDDP) resistance is accompanied by an increase in Nrf2 protein expression which contributes to conferring resistance. Recently, we demonstrated a cross-talk between Nrf2 and YAP. YAP has also been demonstrated to play an important role in chemoresistance of bladder cancer.
Purpose: We analyzed the antitumor effect of Aila in sensitive and CDDP-resistant bladder cancer cells and the molecular mechanisms involved in Aila activity.
Study design: Sensitive and CDDP-resistant 253J B-V and 253J bladder cancer cells, intrinsically CDDP-resistant T24 bladder cancer cells and HK-2 human renal cortex cells were used. Cells were treated with diverse concentrations of Aila and proliferation, cell cycle, apoptosis and gene expressions were determined.
Methods: Aila toxicity and proliferation were determined by MTT and colony forming methods, respectively. Cell cycle was determined by cytofluorimetric analysis through PI staining method. Apoptosis was detected using Annexin V and PI double staining followed by quantitative flow cytometry. Expressions of Nrf2, Yap, c-Myc, and house-keeping genes were determined by western blot with specific antibodies. Cell migration was detected by wound healing and Boyden chamber analysis.
Results: Aila inhibited the growth of sensitive and CDDP-resistant bladder cancer cells with the same effectiveness. On the contrary, the growth of HK-2 cells was only slightly reduced by Aila. Cell cycle analysis revealed an accumulation of Aila-treated bladder cancer cells in the G0/G1 phase. Interestingly, Aila strongly reduced Nrf2 expression in these cell lines. Moreover, Aila significantly reduced YAP, and c-Myc protein expression. The random and the oriented migration of bladder cancer cells were strongly inhibited by Aila treatment, in particular in CDDP-resistant cells.
Conclusion: Aila inhibited proliferation and invasiveness of bladder cancer cells. Its high effectiveness in CDDP resistant cells could be related to the inhibition of Nrf2, YAP, and c-Myc expressions. Aila could represent a new tool to treating CDDP-resistant bladder cancers.
Keywords: Ailanthone; Bladder cancer; C-Myc; CDDP-resistance; Nrf2; Yap.
Copyright © 2018. Published by Elsevier GmbH.