ETHNOPHARMACOLOGICAL RELEVANCE: According to the theory of Qi and blood in Traditional Chinese Medicine (TCM), the combination of Qi-reinforcing herbs and blood-activating herbs has a synergistic effect in improving blood stasis syndrome, especially in tumor treatment. The classic "Radix Astragali - Salvia miltiorrhiza" duo exemplifies this principle, renowned for invigorating Qi and activating blood flow, employed widely in tumor therapies. Our prior research underscores the potent inhibition of pancreatic tumor xenografts by the combination of Formononetin (from Radix Astragali) and Salvianolic acid B (from Salvia miltiorrhiza) in vitro. However, it remains unclear whether this combination can inhibit the abnormal vascularization of pancreatic tumors to achieve its anti-cancer effect.
AIM OF THE STUDY: Abnormal vasculature, known to facilitate tumor growth and metastasis. Strategies to normalize tumor-associated blood vessels provide a promising avenue for anti-tumor therapy. This study aimed to unravel the therapeutic potential of Formononetin combined with Salvianolic acid B (FcS) in modulating pancreatic cancer's impact on endothelial cells, illuminate the underlying mechanisms that govern this therapeutic interaction, thereby advancing strategies to normalize tumor vasculature and combat cancer progression.
MATERIALS AND METHODS: A co-culture system involving Human Umbilical Vein Endothelial Cells (HUVECs) and PANC-1 cells was established to investigate the potential of targeting abnormal vasculature as a novel anti-tumor therapeutic strategy. We systematically compared HUVEC proliferation, migration, invasion, and lumenogenesis in both mono- and co-culture conditions with PANC-1 (H-P). Subsequently, FcS treatment of the H-P system was evaluated for its anti-angiogenic properties. Molecular docking was utilized to predict the interactions between Formononetin and Salvianolic acid B with RhoA, and the post-treatment expression of RhoA in HUVECs was assessed. Furthermore, we utilized shRhoA lentivirus to elucidate the role of RhoA in FcS-mediated effects on HUVECs. In vivo, a zebrafish xenograft tumor model was employed to assess FcS's anti-tumor potential, focusing on cancer cell proliferation, migration, apoptosis, and vascular development.
RESULTS: FcS treatment demonstrated a significant, dose-dependent inhibition of PANC-1-induced alterations in HUVECs, including proliferation, migration, invasion, and tube formation capabilities. Molecular docking analyses indicated potential interactions between FcS and RhoA. Further, FcS treatment was found to downregulate RhoA expression and modulated the PI3K/AKT signaling pathway in PANC-1-induced HUVECs. Notably, the phenotypic inhibitory effects of FcS on HUVECs were attenuated by RhoA knockdown. In vivo zebrafish studies validated FcS's anti-tumor activity, inhibiting cancer cell proliferation, metastasis, and vascular sprouting, while promoting tumor cell apoptosis.
CONCLUSIONS: This study underscores the promising potential of FcS in countering pancreatic cancer-induced endothelial alterations. FcS exhibits pronounced anti-abnormal vasculature effects, potentially achieved through downregulation of RhoA and inhibition of the PI3K/Akt signaling pathway, thereby presenting a novel therapeutic avenue for pancreatic cancer management.