The Effects of Rukangyin on the Biological Behavior and Hippo Signaling Pathway in MDA-MB-231 Breast Cancer Cells.

Introduction: This study aims to examine the impact of Rukangyin (RKY) and its components, LSQR and QTSS, on various cellular processes and signaling mechanisms in MDA-MB-231 triple-negative breast cancer (TNBC) cells.

Methods: Twenty-five Sprague-Dawley (SD) rats were randomly assigned to five groups according to the administered drugs, including the RKY group, LSQR group, QTSS group, fluorouracil group, and blank control group (n=5 in each group). The serum samples from each group were then used as a medicated medium for the culture of the TNBC cell line MDA-MB-231. Cell viability tests, apoptosis detection tests, and migration and invasion tests were used to evaluate the cytotoxicity of treated serum. YAP, TAZ, MST1, and LATS1 protein expression and phosphorylation were examined using conventional western blotting methods.

Results: RKY and its QTSS and LSQR components significantly inhibited cell growth and promoted apoptosis in MDA-MB-231 cells. RKY also significantly blocked cell motility with a comparable effect to that of fluorouracil. All serum groups suppressed YAP and TAZ expressions while increasing p-YAP, p-TAZ, MST1, and LATS1 levels, with RKY showing superior efficacy.

Discussion: In TNBC cells, RKY appears to enhance the tumor-suppressing signals of the Hippo signaling pathway via MST1, LATS1 activation, while restricting its pro-oncogenic action via YAP and TAZ blockade. However, in vivo and animal model experiments are required to confirm these findings.

Conclusion: RKY-medicated serum effectively inhibits growth, induces apoptosis, and reduces motility in the MDA-MB-231 cell line of breast cancer. This therapeutic potential of RKY on TNBC cells draws attention to the need for more investigations.