The Role of Forkhead Box Q1 Transcription Factor in Anticancer Effects of Withaferin A in Breast Cancer

Abstract

Elimination of both rapidly dividing epithelial mammary cancer cells as well as breast cancer stem-like cells (bCSC) is essential for maximizing antitumor response. Withaferin A (WA), a small molecule derived from a medicinal plant (Withania somnifera), is highly effective in reducing burden and/or incidence of breast cancer in vivo in various preclinical models. We have shown previously that suppression of breast cancer incidence by WA administration in a rat model is associated with a decrease in self-renewal of bCSC but the underlying mechanism is still elusive. This study investigated the role of forkhead box Q1 (FoxQ1) transcription factor in antitumor responses to WA. Exposure of MDA-MB-231 and SUM159 cells to WA resulted in downregulation of protein and mRNA levels of FoxQ1 as well as inhibition of its transcriptional activity. FoxQ1 overexpression in SUM159 and MCF-7 cells resulted in a marked protection against WA-mediated inhibition of bCSC as judged by flow cytometric analysis of CD49f high population and mammosphere assay. RNA-seq analysis revealed upregulation of many bCSCassociated genes by FoxQ1 overexpression in SUM159 cells, including interleukin-8 (IL-8) whose expression was decreased by WA treatment in SUM159 and MCF-7 cells. FoxQ1 was recruited to the promoter of IL-8 that was inhibited significantly by WA treatment. On the other hand, WAmediated inhibition of cell proliferation or migration was not affected by FoxQ1 overexpression. The FoxQ1 overexpression partially attenuated WA-mediated G 2 /M phase cell cycle in SUM159 cells only. These results indicate that FoxQ1 is a target of WA for inhibition of bCSC fraction.

Withaferin A mediated changes of miRNA expression in breast cancer‐derived mammospheres

“…16 WA possess anticancer potential as previous reports suggest that WA has the ability to inhibit stemness and self-renewal properties in cancer cells at protein and transcript level. 5,6 To the best of our knowledge, for the first time, we demonstrate the effect of WA on upstream molecular events including changes in the miRNA expression in breast cancerderived mammospheres.…”

“…WA exerts its anticancer effects by targeting FOX3A, STAT3, ERα, p53, and several upstream kinases 4 . Moreover, few studies also reported targeting breast cancer stem cells by WA 5,6 . Modulation of miRNA with a therapeutic agent is a potential strategy to target stemness and self‐renewal properties in breast cancer cells.…”

The Potential Pharmacological Effects of Natural Product Withaferin A in Cancer: Opportunities and Challenges for Clinical Translation

“…Several reports showed WA as being potent for preventing and treating cancer [19][20][21]. However, it remains at the budding stage for clinical use due to a lack of progress in pharmacokinetics, safety, toxicology, and clinical studies.…”

Emerging insights of nutraceuticals as anticancer

“…A steroidal lactone, withaferin-A, obtained from Withania somnifera, has been shown to reduce breast CSC fraction and mammosphere formation in SUM159 and MCF-7 breast cancer cells (Kim & Singh, 2014). Moreover, withaferin A also inhibits the fraction of cancer stem cells in breast tissue by suppressing FoxQ1 (Kim et al, 2021). In cancer cells of the pancreas, withaferin A was found to suppress the activity of the stem cell marker Nestin (Su et al, 2013).…”