Mechanisms of drug resistance mediated by long non-coding RNAs in non-small-cell lung cancer.

Non-small-cell lung cancer (NSCLC) is the most prevalent form of lung cancer and has a poor five-year survival rate of 15%. Chemotherapy and targeted therapies have significantly improved patients' prognosis. Nevertheless, after a successful initial response, some patients relapse when cancer cells become resistant to drug treatments, representing an important clinical limitation. Therefore, investigating the mechanisms of drug resistance is of significant importance. Recently, considerable attention has been given to long non-coding RNAs (lncRNAs), a heterogeneous class of regulatory molecules that play essential roles in tumorigenesis by modulating genes and signalling pathways involved in cell growth, metastasis and drug response. In this article, we review recent research findings on the role of lncRNAs in drug resistance in NSCLC, highlighting their mechanisms of action.

AMPKα loss promotes KRAS-mediated lung tumorigenesis.

AMP-activated protein kinase (AMPK) is a critical sensor of energy status that coordinates cell growth with energy balance. In non-small cell lung cancer (NSCLC) the role of AMPKα is controversial and its contribution to lung carcinogenesis is not well-defined. Furthermore, it remains largely unknown whether long non-coding RNAs (lncRNAs) are involved in the regulation of AMPK-mediated pathways. Here, we found that loss of AMPKα in combination with activation of mutant KRASG12D increased lung tumour burden and reduced survival in KrasLSLG12D/+/AMPKαfl/fl mice. In agreement, functional in vitro studies revealed that AMPKα silencing increased growth and migration of NSCLC cells. In addition, we identified an AMPKα-modulated lncRNA, KIMAT1 (ENSG00000228709), which in turn regulates AMPKα activation by stabilizing the lactate dehydrogenase B (LDHB). Collectively, our study indicates that AMPKα loss promotes KRAS-mediated lung tumorigenesis and proposes a novel KRAS/KIMAT1/LDHB/AMPKα axis that could be exploited for therapeutic purposes.

CKAP2L Promotes Non-Small Cell Lung Cancer Progression through Regulation of Transcription Elongation.

Chromosomal instability (CIN) is a driver of clonal diversification and intratumor heterogeneity, providing genetic diversity that contributes to tumor progression. It is estimated that approximately 80% of solid cancers, including non-small cell lung cancer (NSCLC), exhibit features of CIN, which affects tumor growth and response to therapy. However, the molecular mechanisms connecting CIN to tumor progression are still poorly understood. Through an RNAi screen performed on genes involved in CIN and overexpressed in human lung adenocarcinoma samples, we identified the cytoskeleton-associated protein 2-like (CKAP2L) as a potential oncogene that promotes lung cancer proliferation and growth in vitro and in vivo. Mechanistically, CKAP2L directly interacted with RNA Pol II and regulated transcription elongation of key genes involved in spindle assembly checkpoint, chromosome segregation, cell cycle, and E2F signaling. Furthermore, depletion of CKAP2L increased the sensitivity of NSCLC cells to alvocidib, a pan-CDK inhibitor, leading to a significant reduction of cell proliferation and an increase in cell death. Altogether, these findings shed light on the molecular mechanisms through which CKAP2L, a protein involved in CIN, promotes cancer progression and suggest that its inhibition represents a novel therapeutic strategy in NSCLC. SIGNIFICANCE: These findings demonstrate the oncogenic function of CKAP2L through regulation of transcription elongation and suggest that targeting CKAP2L could enhance therapeutic response in patients with NSCLC.