myrtucommulone-a and Urinary-Bladder-Neoplasms

Mounting evidence suggests that signalling cross-talk plays a significant role in the regulation of epithelial-mesenchymal transition (EMT) in cancer cells. However, the complex network regulating the EMT in different cancer types has not been fully described yet which affects the development of novel therapeutic strategies. In the present study, we investigated the signalling pathways involved in EMT of bladder cancer cells and demonstrated the effects of two novel agents in the regulation of EMT. Myrtucommulone-A (MC-A) and thymoquinone (TQ) have been shown to possess anti-cancer properties. However, their targets in the regulation of cancer cell behavior are not well defined. Here, we defined the effects of two putative anti-cancer agents on bladder cancer cell migration and their possible intracellular targets in the regulation of EMT. Our results suggest that MC-A or TQ treatment affected N-cadherin, Snail, Slug, and β-catenin expressions and effectively attenuated mTOR activity. The downstream components in mTOR signalling were also affected. MC-A treatment resulted in the concomitant inhibition of extracellular matrix-regulated protein kinases 1 and 2 (ERK 1/2), p38 mitogen-activated protein kinase (MAPK) and Src activity. On the other hand, TQ treatment increased Src activity while exerting no effect on ERK 1/2 or p38 MAPK activity. Given the stronger inhibition of EMT-related markers in MC-A-treated samples, we concluded that this effect might be due to collective inhibition of multiple signalling pathways which result in a decrease in their cross-talk in bladder cancer cells. Overall, the data in this study proposes novel action mechanisms for MC-A or TQ in bladder cancer cells and highlights the potential use of these active compounds in the regulation of EMT.

Topics: Antineoplastic Agents; Benzoquinones; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Cell Survival; Colony-Forming Units Assay; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Phloroglucinol; Signal Transduction; TOR Serine-Threonine Kinases; Urinary Bladder Neoplasms; Wound Healing

Cancer and stem cells exhibit similar features, including self-renewal, differentiation and immortality. The expression of stem-cell-related genes in cancer cells is demonstrated to be potentially correlated with cancer cell behaviour, affecting both drug response and tumor recurrence. There is an emerging body of evidence that subpopulations of tumors carry a distinct molecular sign and are selectively resistant to chemotherapy. Therefore, it is important to find novel therapeutic agents that could suppress the stem-like features of cancer cells while inhibiting their proliferation. Myrtucommulone-A (MC-A) is an active compound of a nonprenylated acylphloroglucinol isolated from the leaves of myrtle. Here we have investigated the potential of MC-A in inhibiting the expression of self-renewal regulatory factors and cancer stem cell markers in a bladder cancer cell line HTB-9. We used RT-PCR, immunocytochemistry, flow cytometry and western blotting to examine the expression of pluripotency- and multipotency-associated markers with or without treatment with MC-A. Treatment with MC-A not only decreased cancer cell viability and proliferation but also resulted in a decrease in the expression of pluripotency- and multipotency-associated markers such as NANOG, OCT-4, SOX-2, SSEA-4, TRA-1-60, CD90, CD73 and CD44. MC-A treatment was also observed to decrease the sphere-forming ability of HTB-9 cells. In summary, this study provides valuable information on the presence of stem-cell marker expression in HTB-9 cells and our results imply that MC-A could be utilized to target cancer cells with stem-like characteristics.

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Gene Expression; Humans; Immunohistochemistry; Phloroglucinol; Urinary Bladder Neoplasms