Background

Lung cancer has the highest mortality rate among all cancer types. In combination with multiple chemotherapeutic options, traditional Chinese medicine has proven indispensable for the comprehensive treatment of lung cancer.

Purpose

To investigate the effects of Hedyotis diffusa on lung adenocarcinoma cell lines and a BALB/c nude mouse xenograft model, and determine whether HDI could induce ferroptosis in lung adenocarcinoma cells along with the underlying mechanism.

Methods

The anti-tumor activity of HDI was determined in vitro by cell counting kit-8, clonogenic, and transwell assays. Subsequently, electron microscopy, a lipid reactive oxygen species assay, ferrous ion staining, and a malondialdehyde assay were performed to determine the effect on ferroptosis in lung adenocarcinoma cells. The mechanism was then further investigated using small molecule inhibitors, siRNA, and plasmid overexpression in vitro. Finally, the effects of HDI were assessed in tumor-bearing BALB/c nude mice, and HE staining was performed to observe tissue damage after HDI treatment.

Results

In vitro experiments showed that HDI could inhibit the viability of lung adenocarcinoma cells and induce lung adenocarcinoma cells ferroptosis via mechanisms independent of GPX4 and PUFA-PLS pathways but closely associated with VDAC2/3. HDI regulated VDAC2/3 activity by promoting Bax via inhibiting Bcl2, thereby inducing ferroptosis in lung adenocarcinoma cells. Furthermore, in vivo experiments showed that HDI significantly inhibited the growth of subcutaneous tumors in BALB/c nude mice with less organ damage and toxicity, and significantly increased the expression of the ferroptosis-related indicators 4HNE, TFR, and HMOX1 in tumor tissue.

Conclusion

HDI can significantly reduce the survival of lung adenocarcinoma cells in vitro, inhibit the growth of subcutaneously transplanted tumors in BALB/c nude mice in vivo, and induce ferroptosis in lung adenocarcinoma cells via Bcl2 inhibition to promote Bax regulation of VDAC2/3.