Leukocyte Telomere Length and Clinical Outcomes of Advanced Lung Adenocarcinoma Patients with Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors Treatment

Role of telomere length in human carcinogenesis (Review)

Cancer is considered the most important clinical, social and economic issue regarding cause‑specific disability‑adjusted life years among all human pathologies. Exogenous, endogenous and individual factors, including genetic predisposition, participate in cancer triggering. Telomeres are specific DNA structures positioned at the end of chromosomes and consist of repetitive nucleotide sequences, which, together with shelterin proteins, facilitate the maintenance of chromosome stability, while protecting them from genomic erosion. Even though the connection between telomere status and carcinogenesis has been identified, the absence of a universal or even a cancer‑specific trend renders consent even more complex. It is indicative that both short and long telomere lengths have been associated with a high risk of cancer incidence. When evaluating risk associations between cancer and telomere length, a disparity appears to emerge. Even though shorter telomeres have been adopted as a marker of poorer health status and an older biological age, longer telomeres due to increased cell growth potential are associated with the acquirement of cancer‑initiating somatic mutations. Therefore, the present review aimed to comprehensively present the multifaceted pattern of telomere length and cancer incidence association.

LncRNAs LCETRL3 and LCETRL4 at chromosome 4q12 diminish EGFR-TKIs efficiency in NSCLC through stabilizing TDP43 and EIF2S1

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are effective targeted therapy drugs for advanced non-small cell lung cancer (NSCLC) patients carrying sensitized EGFR mutations. The rapid development of EGFR-TKIs resistance represents a major clinical challenge for managing NSCLC. The chromosome 4q12 is the first genome-wide association study (GWAS)-reported locus associated with progression-free survival (PFS) of NSCLC patients treated with EGFR-TKIs. However, the biological significance of the noncoding transcripts at 4q12 in NSCLC remains elusive. In the present study, we identified two 4q12 long noncoding RNAs (lncRNAs) LCETRL3 and LCETRL4 which could significantly dimmish EGFR-TKIs efficiency. In line with their oncogenic role, evidently higher LCETRL3 and LCETRL4 levels were observed in NSCLC tissues as compared with normal specimens. Importantly, lncRNA LCETRL3 can interact with oncoprotein TDP43 and inhibit ubiquitination and degradation of TDP43. Similarly, lncRNA LCETRL4 can bind and stabilize oncoprotein EIF2S1 through reducing ubiquitin-proteasome degradation of EIF2S1. In particular, elevated levels of LCETRL3 or LCETRL4 in NSCLC cells resulted in stabilization of TDP43 or EIF2S1, increased levels of NOTCH1 or phosphorylated PDK1, activated AKT signaling and, thus, EGFR-TKIs resistance. Taken together, our data revealed a novel model that integrates two lncRNAs transcribed from the 4q12 locus into the regulation of EGFR-TKIs resistance in NSCLC. These findings shed new light on the importance of functionally annotating lncRNAs in the GWAS loci and provided insights to declare novel druggable targets, i.e., lncRNAs, which may unlock the therapeutic potential of EGFR-TKIs resistant NSCLC in the clinic.