PLCγ1‑dependent invasion and migration of cells expressing NSCLC‑associated EGFR mutants

Autor: Maitreyi S. Rajala, Ann M. Joseph, Arpana Kamath, Sonam Mittal
Rok vydání: 2020
Předmět:
Zdroj: International Journal of Oncology.
ISSN: 1791-2423
1019-6439
DOI: 10.3892/ijo.2020.5112
Popis: The increased tyrosine kinase activity of non­small cell lung cancer (NSCLC)­associated epidermal growth factor receptor (EGFR) mutants results in deregulated pathways that contribute to malignant cell survival, tumor progression and metastasis. Previous studies investigating lung cancer­associated EGFR have focused on the prognostic implications of receptor kinase mutations in patients with NSCLC; however, the role of EGFR mutations in tumor cell invasion and migration remains undetermined. The present study was designed to investigate the role of NSCLC­associated mutant EGFR­driven signaling pathways in cell proliferation and invasion. Non­endogenous EGFR­expressing 293 cells stably expressing EGFR mutants that are sensitive or resistant to Food and Drug Administration (FDA)­approved EGFR­targeted tyrosine kinase inhibitors (TKIs) were used in the present study. The experiments demonstrated an increased phosphorylation of phospholipase (PLC)I³1, c­Cbl, signal transducer and activator of transcription (Stat), extracellular regulated kinase (Erk)1/2, Akt, Shc and Gab1 proteins in cells expressing a mutant form, rather than the wild­type receptor. As PLCI³1 is a known regulator of metastatic development, mutant receptor­mediated PLCI³1 activation was further evaluated. To examine the effects of EGFR and PLCI³1 phosphorylation, the metastatic potential of cells expressing mutants was investigated using wound healing, Transwell cell migration and invasion assays. The inhibition of receptor phosphorylation with the 1st, 2nd and 3rd generation TKIs, gefitinib, afatinib, osimertinib, respectively, reduced PLCI³1 phosphorylation, and reduced the invasive and migratory potential of 293 cells, confirming PLCI³1 as one of the probable downstream effectors of mutant EGFR signaling. However, the PLC inhibitor, U73122, inhibited cell migration and invasion without affecting EGFR signaling and PLCI³1 phosphorylation. Notably, U73122 reduced Akt and Erk1/2 phosphorylation within 25 min of its application; however, 100% cell viability was recorded even after 48 h. Upon further investigation, proliferative signaling pathways remained active at 48 h, in accordance with cell viability. Therefore, the present study concludes that mutant receptor­mediated PLCI³1 activation may play a significant role in the migration and invasion of NSCLC tumors; however, its regulatory role in tumor cell proliferation warrants further investigation and validation in lung tumor cell lines harboring EGFR mutations.
Databáze: OpenAIRE