Blaps rynchopetera combined with cyclophosphamide affects proliferation and apoptosis of lung cancer cells via Wnt/β-catenin signaling pathway

Abstract

This study aims to investigate the effects of Blaps rynchopetera Fairmaire and/or cyclophosphamide on the proliferation and apoptosis of lung cancer cells and decipher the underlying mechanism. B. rynchopetera and cyclophosphamide-containing serum and blank serum were prepared from SD rats. Cell counting kit-8(CCK-8) assay was employed to examine the proliferation of lung cancer cell lines A549 and Lewis treated with corresponding agents. The Jin's formula method was used to evaluate the combined effect of the two drugs. According to the evaluation results, appropriate drug concentrations and lung cancer cell line were selected for subsequent experiments, which included control, B. rynchopetera, cyclophosphamide, B. rynchopetera + cyclophosphamide, and B. rynchopetera + Wnt/β-catenin pathway agonist lithium chloride(LiCl) groups. Immunocytochemistry was employed to measure the expression of proliferation-related proteins in Lewis cells after drug interventions. Flow cytometry was employed to determine the cell cycle and apoptosis. The expression levels of proliferating cell nuclear antigen(PCNA), cyclinD1, B-cell lymphoma 2(Bcl-2), Bcl-2-assiocated X protein(Bax), Wnt1, and β-catenin were determined by Western blot. The results showed that B. rynchopetera and/or cyclophosphamide significantly inhibited the proliferation of A549 and Lewis cells. Compared with B. rynchopetera alone, the combination increased the inhibition rate on cell proliferation. The combination of B. rynchopetera and cyclophosphamide demonstrated a synergistic effect according to Jin's formula-based evaluation. Compared with the control group, the B. rynchopetera, cyclophosphamide, and B. rynchopetera + cyclophosphamide groups showed increased proportion of Lewis cells in G_0/G_1 phase, increased apoptosis rate, up-regulated expression of Bax, and down-regulated expression of PCNA, cyclinD1, Bcl-2, Wnt1, and β-catenin. Compared with the cyclophosphamide group, the combination group showed increased proportion of cells in G_0/G_1 phase, increased apoptosis rate, up-regulated expression of Bax, and down-regulated expression of PCNA, cyclinD1, Bcl-2, Wnt1, and β-catenin. Compared with the B. rynchopetera group, the B. rynchopetera + LiCl group had deceased proportion of cells in G_0/G_1 phase, decreased apoptosis rate, down-regulated expression of Bax, and up-regulated expression of PCNA, cyclinD1, Bcl-2, Wnt1, and β-catenin. The results indicated that B. rynchopetera could inhibit the proliferation, arrest the cell cycle, and induce the apoptosis of lung cancer cells by inhibiting the Wnt/β-catenin signaling pathway. Moreover, B. rynchopetera had a synergistic effect with cyclophosphamide.