A New Treatment Strategy for Lung Cancer With HDAC and Wnt/β-Catenin Pathway Inhibitors.

Lung cancer is a type of cancer with high morbidity and mortality rates worldwide. The overall survival rate of lung cancer patients is low due to a lack of therapeutic options. Recently, the combination of histone deacetylase (HDAC) inhibitors with anti-cancer agents offers a promising therapeutic strategy for cancer treatment. Repurposing these drug combinations is important to evaluate their preventive effect on the epithelial mesenchymal transition (EMT) phenotype, which plays a critical role in tumor progression and metastasis. In this study, the changes that the combination of the HDAC inhibitor Valproic acid (VPA) and Wnt/β-Catenin pathway inhibitor Niclosamide (Niclo) may cause in cytotoxicity, apoptosis, cell cycle, and EMT mechanisms in lung cancer cell lines (A549 and H1299) were examined. According to the results, the combination of VPA + Niclo significantly reduced cell viability in lung cancer cells compared to the use of Niclo alone. ELISA and Western blot analyses revealed that the combination of VPA + Niclo significantly enhanced the total acetylation of Histone H3 compared to the use of VPA alone. It was also found that the combination treatment induced apoptosis by increasing the activity of Caspase 3/7 and Annexin-V and significantly increased the percentage of apoptotic cells by causing depolarization of mitochondria. After cell cycle analysis, the combination treatment increased G1 phase retention in A549 cells, while G1-G2/M phase retention increased in H1299 cells. Wound healing and transwell migration assay results showed that the VPA + Niclo combination treatment inhibited cell migration in lung cancer cells. According to Western blot and PCR results, after VPA + Niclo treatment, the increase in E-Cadherin levels and the decrease in β-Catenin, Fibronectin, Vimentin, and N-Cadherin levels at both protein and gene levels indicated that combination therapy may be useful in preventing the EMT process in lung cancer cells. As a result of the analyses, it was seen that VPA + Niclo combination therapy could play a critical role in preventing the acquisition of the mesenchymal phenotype, reducing cell migration and invasion ability, and preventing tumor cell survival and resistance to apoptosis. In conclusion, it was determined that VPA + Niclo combination treatment shows anticancer activity in lung cancer cells and is a promising approach that may have a synergistic effect in inhibiting EMT.