Genome-wide CRISPR-Cas9 screening identifies ITGA8 responsible for abivertinib sensitivity in lung adenocarcinoma

The emergence of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) has improved the prognosis for lung cancer patients with EGFR-driven mutations. However, acquired resistance to EGFR-TKIs poses a significant challenge to the treatment. Overcoming the resistance has primarily focused on developing next-generation targeted therapies based on the molecular mechanisms of resistance or inhibiting the activation of bypass pathways to suppress or reverse the resistance. In this study we developed a novel approach by using CRISPR-Cas9 whole-genome library screening to identify the genes that enhance the sensitivity of lung adenocarcinoma cells to EGFR-TKIs. Through this screening, we revealed integrin subunit alpha 8 (ITGA8) as the key gene that enhanced sensitivity to abivertinib in lung adenocarcinoma. Notably, ITGA8 expression was significantly downregulated in lung adenocarcinoma tissues compared to adjacent normal tissues. Bioinformatics analyses revealed that ITGA8 was positively correlated with the sensitivity of lung adenocarcinoma to abivertinib. We showed that knockdown of ITGA8 significantly enhanced the proliferation, migration and invasion of H1975 cells. Conversely, overexpression of ITGA8 reduced the proliferation migration and invasion of H1975/ABIR cells. Furthermore, we demonstrated that ITGA8 sensitized lung adenocarcinoma cells to EGFR-TKIs by attenuating the downstream FAK/SRC/AKT/MAPK signaling pathway. In H1975 cell xenograft mouse models, knockdown of ITGA8 significantly increased tumor growth and reduced the sensitivity to abivertinib, whereas overexpression of ITGA8 markedly suppressed tumor proliferation and enhanced sensitivity to the drug. This study demonstrates that ITGA8 inhibits the proliferation, invasion and migration of lung adenocarcinoma cells, enhances the sensitivity to EGFR-TKIs, improves treatment efficacy, and delays the progression of acquired resistance. Thus, ITGA8 presents a potential therapeutic candidate for addressing acquired resistance to EGFR-TKIs from a novel perspective.