ANNOUNCEMENTS
Lung cancer is the most common type of cancer, accounting for one in every 5 cancer-related deaths worldwide. The major reason for this is the high relapse rate and over a period of treatment, this cancer acquires resistance to drugs, which is the biggest challenge in treatment. In our study, we mainly focused on activating innate immunity in drug-resistant lung adenocarcinoma cells NCI H23. The major goal of the study is to resensitize drug-resistant cells to treatment-mediated cell death though activating cGAS-STING signaling. CGAS is dependent on damaged DNA for its activation, which is very common in cancer cells. To prevent its activation, cancer cells have a defense mechanism that is an exonuclease called TREX1, which cleans up this damaged DNA and prevents any innate immunity activation. In our study, we used STING agonist (2,3 CGAMP) to directly activate the cGAS signaling. We used four experimental cell models; parent cell, agonist-treated parent cell, drug resistance cells, and agonist-treated drug-resistant cells. Following treatment, RNA was isolated and gene expression analysis was performed, revealing a marked upregulation of TREX1 and cGAS, an indicative of substantial DNA damage. The accumulation of cytoplasmic DNA appeared to overwhelm TREX1, thereby insisting cGAS activation. Gene expression analysis further identified elevated expression of ABCB1, a well-established marker of drug resistance. Notably, treatment with the agonist significantly reduced ABCB1 levels to those seen in non-resistant cells, suggesting a re-sensitization of drug-resistant populations. These findings open several promising directions for future research, including the investigation of protein expression and subcellular localization of STING, TREX1, and cGAS; the potential roles of micronuclei and chromatin bridges in cGAS activation; and combination strategies that integrate autophagy inhibition with reversal of resistance mechanisms. Moreover, in vivo validation using immunocompromised tumor xenograft models will be essential. Overall, this study enhances our understanding of the molecular mechanisms underlying drug resistance in lung cancer and highlights new avenues for therapeutic intervention.
