Rechallenge with erlotinib in osimertinib-resistant lung adenocarcinoma mediated by driver gene loss: a case report

Transcriptomic Analysis Reveals Early Alterations Associated with Intrinsic Resistance to Targeted Therapy in Lung Adenocarcinoma Cell Lines

Lung adenocarcinoma is the most prevalent form of lung cancer, and drug resistance poses a significant obstacle in its treatment. This study aimed to investigate the overexpression of long non-coding RNAs (lncRNAs) as a mechanism that promotes intrinsic resistance in tumor cells from the onset of treatment. Drug-tolerant persister (DTP) cells are a subset of cancer cells that survive and proliferate after exposure to therapeutic drugs, making them an essential object of study in cancer treatment. The molecular mechanisms underlying DTP cell survival are not fully understood; however, long non-coding RNAs (lncRNAs) have been proposed to play a crucial role. DTP cells from lung adenocarcinoma cell lines were obtained after single exposure to tyrosine kinase inhibitors (TKIs; erlotinib or osimertinib). After establishing DTP cells, RNA sequencing was performed to investigate the differential expression of the lncRNAs. Some lncRNAs and one mRNA were overexpressed in DTP cells. The clinical relevance of lncRNAs was evaluated in a cohort of patients with lung adenocarcinoma from The Cancer Genome Atlas (TCGA). RT-qPCR validated the overexpression of lncRNAs and mRNA in the residual DTP cells and LUAD biopsies. Knockdown of these lncRNAs increases the sensitivity of DTP cells to therapeutic drugs. This study provides an opportunity to investigate the involvement of lncRNAs in the genetic and epigenetic mechanisms that underlie intrinsic resistance. The identified lncRNAs and CD74 mRNA may serve as potential prognostic markers or therapeutic targets to improve the overall survival (OS) of patients with lung cancer.

Apatinib has anti-tumor effects and induces autophagy in lung cancer cells with high expression of VEGFR-2

Objectives

This study investigated the inhibitory effect of apatinib on lung cancer cells with high expression of vascular endothelial growth factor-2 (VEGFR-2) and on inducing cellular autophagy and drug resistance.

Materials and Methods

The expression of VEGFR-2 was detected using western blotting and RT-PCR. Cell proliferation was measured using the CCK8 and colony formation assays. The cell apoptosis rate was determined using flow cytometry and tunnel assay. Cellular autophagy was detected by measuring the expression of LC3-II using Western blotting and cellular immunofluorescence. The inhibitory effect of apatinib on lung cancer cells and transplanted tumors was observed after treatment with the autophagy inhibitor chloroquine.

Results

Apatinib dose-dependently inhibited the proliferation of H1975 and H446 cells; it induced apoptosis via the PARP and caspase-3 pathways in H1975 and H446 cells and effectively inhibited the growth of transplanted tumors. Apatinib induced autophagy in a dose-dependent manner in H1975 and H446 cells. The inhibitory effect of apatinib on cells and the promotion of apoptosis were significantly enhanced after treatment with chloroquine. Immunohistochemistry showed that combining apatinib with chloroquine could reduce the expression of CD31 and Ki67 and increase the expression of caspase-3.

Conclusion

Apatinib inhibits proliferation and induces apoptosis in H1975 and H1446 lung cancer cells with high VEGFR2 expression and autophagy in H1975 and H446 cells.

Overcoming Osimertinib Resistance in Advanced Non-small Cell Lung Cancer

Osimertinib is used as a first-line treatment for metastatic non-small cell lung cancer with positive epidermal growth factor receptor mutations based on the results of the FLAURA trial. However, as with any other epidermal growth factor receptor tyrosine kinase inhibitor, resistance also develops for osimertinib. Various genetic aberrations associated with the molecular heterogeneity of cancer cells contribute to osimertinib resistance. It is also important to choose an appropriate subsequent treatment for osimertinib-resistant non-small cell lung cancer. In this overview, we discuss the underlying mechanisms of osimertinib resistance and the efficacy of possible subsequent treatment measures.