Effects of Ursolic Acid in Extracts of Prunella vulgaris on the Proliferation of Thyroid Papillary Carcinoma Cells Under the p53MAPK Signaling Pathway

Abstract

The aim of this research was to demonstrate the impact of ursolic acid (UA) in Prunella vulgaris extracts on the proliferation of papillary thyroid carcinoma (PTC) cells through the p53MAPK signaling. Effects of Prunella vulgaris extracts on TPC-1 cell proliferation were analyzed by intervening with various concentrations of UA, including negative control (NC) group, solvent control (SC) group, 3 μM UA group, 6 μM UA group, 12 μM UA group, and 15 μM UA group. Flow cytometry was adopted to evaluate apoptosis in TPC-1 cells, while real-time fluorescent quantitative (RT-q) PCR was implemented to assess expression (EP) of Bax and Bcl-2 in TPC-1 cells following UA intervention. RT-qPCR and Western blotting were employed to examine the differential EP levels of cell apoptosis, Bax, and Bcl-2 proteins. RT-qPCR was utilized to investigate the influence of UA on EP of various genes in MAPK pathway. The ethyl acetate extract exhibited the most notable inhibitory effect on TPC-1 cells. The content of UA in Prunella vulgaris increased gradually with the extension of ultrasonic time. The growth curve of TPC-1 cells demonstrated an initial increase followed by a decrease with increasing time. As the concentration increased, cell proportion in S phase increased, while the proportions in the GO-G1 and G2-M phases decreased, indicating that UA concentration-dependently arrested cells in the S phase. The level of Bax mRNA exhibited an increasing trend with increasing concentration, and the 12 μM UA and 15 μM UA groups demonstrated remarkable differences versus NC group (P <0.01). Bcl-2 protein demonstrated a decreasing trend with increasing concentration, and the 6 μM UA, 12 μM UA, and 15 μM UA groups exhibited considerable differences relative to NC group (P < 0.05). Additionally, pro-apoptotic protein Bax increased, while that of anti-apoptotic protein Bcl-2 decreased. UA treatment upregulated EP of the p53 gene in the MAPK pathway. Genes such as ERK, MEK, TSHR, Ras, p53, BRAF, PAK4, and PAKCa were downregulated. In summary, UA can upregulate EP of the p53 gene in the MAPK pathway, greatly inhibit proliferation of TPC-1 cells in PTC, and promote apoptosis. These findings provide insights for therapy of thyroid cancer.