Targeting cancer stem cells is critical for suppressing cancer progression and recurrence. Finding novel markers or related pathways could help eradicate or diagnose cancer in clinic. By constructing STARD13-correlated ceRNA 3′UTR stable overexpression or knockdown breast cancer cells, we aimed to explore the effects of STARD13-correlated ceRNA network on breast cancer stemness in vitro and in vivo. Further RNA-sequencing was used to analyze transcriptome change in combination with functional studies on candidate signaling. Clinical samples obtained from The Cancer Genome Atlas data were used to validate the correlation between STARD13 and related pathways. Finally, in vitro and in vivo experiments were used to examine the effects of STARD13-correlated ceRNA network on chemotherapy sensitivity/resistance. Here, we revealed that this ceRNA network inhibited stemness of breast cancer. Mechanistically, we found that activation of STARD13-correlated ceRNA network was negatively correlated with YAP/TAZ activity in breast cancer. Specifically, this ceRNA network attenuated YAP/TAZ nuclear accumulation and transcriptional activity via collectively modulating Hippo and Rho-GTPase/F-actin signaling. Finally, we demonstrated that YAP/TAZ transcriptional activity regulated by this ceRNA network was involved in chemoresistance. Our results uncover a novel mechanism of YAP/TAZ activation in breast cancer and propose the possibility to drive STARD13-correlated ceRNA network to inhibit breast cancer stem cell traits.

The imbalance between Th17 and Treg cells substantially contributes to the intestinal immune disturbance and subsequent tissue injury in ulcerative colitis. The triterpenoid-rich fraction of Centella asiatica was able to ameliorate dextran sulfate sodium-induced colitis in mice. Here we explored its active ingredient and underlying mechanism with a focus on restoring the Th17/Treg balance. The four main triterpenoids occurring in C. asiatica were shown to attenuate colitis in mice by oral administration. The most effective ingredient madecassoside lost anti-colitis effect when applied topically in the colon, and madecassic acid was recognized to be the active form of madecassoside. Oral administration of madecassic acid decreased the percentage of Th17 cells and downregulated the expression of RORγt, IL-17A, IL-17F, IL-21 and IL-22 and increased the percentage of Treg cells and the expression of Foxp3 and IL-10 in the colons of mice with colitis, but it did not affect Th1 and Th2 cells. Under Th17-polarizing conditions, madecassic acid downregulated ACC1 expression and enhanced the shift of Th17 cells toward Treg cells, but it did not affect the differentiation of Treg cells under Treg-polarizing conditions. Both compound C and AMPK siRNA inhibited the madecassic acid-mediated downregulation of ACC1 expression and shift of Th17 cells to Treg cells under Th17-polarizing conditions. GW9662, T0070907 and PPARγ siRNA blocked the effect of madecassic acid on AMPK activation, ACC1 expression and shift of Th17 cells to Treg cells. Furthermore, madecassic acid was identified as a PPARγ agonist, as it promoted PPARγ transactivation. The correlation between activation of PPARγ and AMPK, downregulation of ACC1 expression, restoration of Th17/Treg balance and attenuation of colitis by madecassic acid was validated in mice with DSS-induced colitis. In conclusion, madecassic acid was the active form of madecassoside in ameliorating colitis by restoring the Th17/Treg balance via regulating the PPARγ/AMPK/ACC1 pathway.