Lanatoside C induces ferroptosis in non-small cell lung cancer in vivo and in vitro by regulating SLC7A11/GPX4 signaling pathway

Background: Non-small cell lung cancer (NSCLC) is a common malignant tumor worldwide, remaining resistant to chemotherapy drugs. Lanatoside C can inhibit the growth of cancer cell lines. In this study we aimed to investigate the relationship between lanatoside C and ferroptosis, exploring the possible mechanism in NSCLC. Methods: Experiments in vitro and in vivo were conducted. A549 cells were used for in vitro, including cell counting kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) release, western blotting, flow cytometry, transmission electron microscopy (TEM), and confocal microscopy. In vivo, a subcutaneous tumor model in nude mice using A549 cells was built and body size of the mice was observed. Ki67 immunohistochemistry, hematoxylin-eosin (HE) staining, and western blotting were conducted respectively. Results: The results showed that lanatoside C had an inhibitory effect on the growth of A549 cells, and the dose of lanatoside C used in this experiment was set at 0.4 mu M for 24 hours. When A549 cells were treated with lanatoside C, the cell viability was decreased observably (P<0.001) and LDH release was significantly enhanced (P<0.01) compared with the control group. However, when A549 cells were treated together with lanatoside C and five different inhibitors, containing ferroptosis inhibitors, necroptosis inhibitors, apoptosis inhibitors, pyroptosis inhibitors, and autophagy inhibitors, the results showed that the viability of A549 cells with lanatoside C and ferrostatin-1 (Fer-1) was reduced (P>0.05) and the LDH release was significantly enhanced (P<0.05). Besides, TEM and confocal microscopy showed that the mitochondria of A549 cells in the lanatoside C group disappeared and the mitochondrial membrane potential decreased. In vivo, lanatoside C efficiently enhanced the sensitivity of the xenograft tumors, as well as reducing the size and weight of the tumor. Moreover, immunohistochemical staining analysis revealed that the SLC7A11 and GPX4 levels significantly decreased in the lanatoside C group. In addition, the expression of GPX4 and SLC7A11 by western blotting was decreased in lanatoside C group. Conclusions: Collectively, lanatoside C could inhibit the proliferation and induce ferroptosis, and have a biological effect on inducing ferroptosis in NSCLC.