Xihuang Pill suppresses breast cancer malignancy by inhibiting TGF-β signaling and acquires chemotherapy benefits

Ethnopharmacological relevance: Breast cancer (BC) has an extremely high global incidence rate. The Xihuang pill (XHP), a traditional Chinese formula, originates from Hongxu Wang's "Life-Saving Manual of Diagnosis and Treatment of External Diseases" written during the Qing Dynasty. In this book, XHP, was first suggested as an anticancer treatment for BC. However, the regulatory mechanism of XHP on BC requires further investigated.

Aim of the study: To assess the effects of XHP on BC and elucidate the underlying associated signaling network.

Materials and methods: The influence of XHP on cellular viability, proliferation, and apoptosis of MDA-MB-231 and BT-549 cells were examined. The ability to metastasize was evaluated using Transwell invasion and wound healing tests. Western blotting was used to examine the epithelial-mesenchymal transition (EMT) markers expression. RNA sequencing and bioinformatic analysis were utilized to investigate the regulation mechanism of XHP. A subcutaneous tumor model was developed to study the tumor-inhibitory effects of XHP or/and Doxorubicin (Dox) on BALB/c nude mice, and the EMT marker levels in tumor tissues were determined using immunohistochemical labeling.

Results: XHP demonstrated anticancer effects on BC cells by suppressing cell proliferation, inducing cellular apoptosis, and inhibiting EMT progression. XHP may regulate the EMT via the TGF-β axis, as shown by RNA sequencing and Western blotting analysis. Furthermore, the combination of XHP and Dox had a stronger therapeutic effect on BC cell proliferation, apoptosis, and metastasis in both cellular and animal models.

Conclusions: We were the first to reveal that XHP abrogated EMT progression via modulating the TGF-β axis. Furthermore, the combination therapy of XHP and Dox presents a promising novel therapeutic candidate for BC patients.