Transcriptomics Reveals the Mechanism of Platycodin D Targeting TGFβ for Anti-Lung Cancer Activity

Lung cancer is the most prevalent and lethal malignant tumor in China, primarily categorized into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC accounts for more than 80% of all lung cancer cases, with current treatments primarily consisting of surgery, chemotherapy, and targeted therapy. However, these treatments often come with various adverse effects and drug resistance issues, highlighting the urgent need for new NSCLC therapies. Traditional Chinese medicine serves as a natural treasury of medicinal compounds and an important avenue for discovering novel active compounds. Platycodin D (PD) is a triterpenoid saponin isolated from the roots of Platycodon, possessing various pharmacological properties. Nevertheless, the exact mechanism of PD's anti-lung cancer activity remains unclear. In this study, 3 lung cancer cell models, A549, NCI-H1299, and PC-9, were employed. After intervention with Platycodin-D, tumor cell proliferation and migration were assessed. Cell migration ability was assessed through transwell assays, while transcriptomics was employed to explore the mechanism of PD's anticancer activity. Bioinformatic analysis revealed significant enrichment of apoptosis and the TGFβ pathway following PD intervention, as shown in gene expression heatmaps, where genes associated with cancer were significantly downregulated by PD intervention. Subsequently, we used immunofluorescent labeling of KI-67 to evaluate cell proliferation, flow cytometry to assess apoptosis, and Western blot to detect protein expression of TGFβ and P-SMAD3. Immunofluorescence was also employed to investigate E-cadherin, vimentin, and N-cadherin. Finally, molecular docking and dynamic simulations were utilized to study the interaction between PD and TGFβ proteins. The results of this study indicate that PD exhibits robust anti-lung cancer pharmacological activity, with its primary target being TGFβ. PD may serve as a potential TGFβ inhibitor and a candidate drug for NSCLC treatment.