A natural xanthone suppresses lung cancer growth and metastasis by targeting STAT3 and FAK signaling pathways

Background: Nonsmall-cell lung cancer (NSCLC) is one of the most common malignant tumors, and the current drugs have not achieved ideal therapeutic effects. The abnormal activation of STAT3 and FAK signal transduction in tumor cells is highly correlated with their proliferation and migration ability. Therefore, bioactive compounds that can inhibit STAT3 and FAK activation have the potential to become agents to treat NSCLC. Purpose: This study aims to discover new antitumor compounds from Garcinia xipshuanbannaensis and investigate the molecular mechanism by which they inhibit lung cancer proliferation and metastasis in vivo and in vitro, all of which may lead to obtainment of a potential antitumor agent. Methods: Xipsxanthone H was obtained by various chromatography methods (including silica gel, medium pressure liquid chromatography (MPLC), and preparative high-performance liquid chromatography (HPLC)). 1D and 2D nuclear magnetic resonance (NMR) spectra were used to analyze the structure. Cell viability and wound healing assays were employed to detect changes in the proliferation and migration of cancer cells. Cell cycle and apoptosis were analyzed by flow cytometry. The protein expression of STAT3 and FAK signaling pathways affected by xipsxanthone H was determined by Western blotting. The zebrafish model was used to evaluate the in vivo effects of xipshantone H on tumor proliferation and metastasis. Molecular docking was utilized to explore the interaction between xipsxanthone H and STAT3. Cellular thermal shift assays (CETSAs) were employed to explore the possible target of xipsxanthone H. Results: The novel compound xipsxanthone H was purified and characterized from G. xipshuanbannaensis. Xipsxanthone H exhibited strong anti-proliferation activity in a variety of tumor cell lines. In addition to inducing reactive oxygen species (ROS) production and arresting the cell cycle, mechanistic studies demonstrated that xipsxanthone H suppressed STAT3 and FAK phosphorylation and regulated the downstream protein expression of the STAT3 and FAK signaling pathways. The in vivo studies using the zebrafish model revealed that xipsxanthone H inhibited tumor proliferation, metastasis, and angiogenesis. Conclusions: A new xanthone was obtained from G. xipshuanbannaensis, and this compound had the property of inhibiting tumor proliferation and metastasis by targeting STAT3 and FAK signaling pathways in NSCLC. These findings suggested that xipsxanthone H might be a potential candidate agent for NSCLC treatment.