Tailored modulation of stemness and drug resistance marker characteristics in K-Ras mutant lung cancer cells via PD-L1 gene suppression.

Aims: We aimed to analyze the association of tumor cell-specific Programmed Cell Death Ligand 1 (PD-L1) expression with stemness markers and multi-drug resistance genes in non-small cell lung cancer.
Main Methods: ATP Binding Cassette Subfamily G Member 2 (ABCG2), Aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), CD44, Epithelial cell adhesion molecule (EPCAM), Kruppel-like factor 4 (KLF4), MYC Proto-Oncogene (MYC), Nanog Homeobox (NANOG), SRY-Box Transcription Factor 2 (SOX2) as well as ATP Binding Cassette Subfamily C Member (ABCC) 1-6, ABCC10-12 with ATP Binding Cassette Subfamily B Member (ABCB) 1 and ABCB4-9 belongs to ABC transporters family were analyzed and their correlation with PD-L1 was evaluated using Cancer Cell Line Encyclopedia and The Cancer Genome Atlas data sets. We validated potential lung cancer stemness markers harboring ABCG2, CD44, ALDH1A1 and SOX-2, which are affected as a result of siRNA-mediated suppression of PD-L1 via flow cytometry. K-Ras downstream signaling proteins as well as multidrug resistance proteins were also investigated.
Key Findings: PD-L1 was found to be positively correlated with CD44, whereas negatively correlated with ALDH1A1 (Pearson r = 0.44, r = -0.48; respectively) in 45 K-Ras mutated NSCLC cells based on CCLE database. While ABCC5 was dominantly decreased in K-Ras mutant lung cancer cells affected by PD-L1 gene suppression, expression changes were observed in the activation of distinct signaling pathways in a cell line-dependent manner.
Significance: The evaluation of markers in lung adenocarcinoma with different types of K-Ras mutations in terms of both stemness and drug resistance markers will contribute to the development of personalized immunotherapy regimens.
Competing Interests: Declaration of competing interest There is no conflict of interest.
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