EGFR-AS1 Promotes Nonsmall Cell Lung Cancer (NSCLC) Progression via Downregulating the miR-524-5p/DRAM1 Axis and Inhibiting Autophagic Lysosomal Degradation

Nonsmall cell lung cancer (NSCLC) accounts for the majority of lung cancers. Studies have revealed the regulatory role of lncRNAs in cancer pathogenesis and their potential use as diagnostic and prognostic biomarkers. The epidermal growth factor receptor antisense RNA 1 (EGFR-AS1) has been reported to be upregulated in NSCLC tissues, while its detailed mechanism in lung cancer needs to be explored. DNA damage-regulated autophagy modulator 1 (DRAM1) has been known to act as a tumor suppressor in NSCLC, and miR-524-5p has been reported to be a biomarker in idiopathic pulmonary fibrosis and different lung disorders. Our investigation revealed that EGFR-AS1 is highly expressed in lung cancer tissues, and its knockdown inhibited lung cancer cell invasion and viability and reduced tumor growth in vivo. We also found that EGFR-AS1 targets miR-524-5p, and there was a negative correlation between their expressions in lung cancer tissues. Simultaneously, miR-524-5p has been found to promote DRAM1 expression. In addition, the inhibition of miR-524-5p diminished DRAM1 protein expression and promoted lung cancer cell invasion. Our study has revealed that EGFR-AS1 contributes to the pathogenesis of NSCLC by inhibiting autophagic-lysosomal degradation via targeting the miR-524-5p/DRAM1 axis. This finding elucidated for the first time the role of EGFR-AS1 in lung cancer progression and the positive regulatory function of miR-524-5p in regulating DRAM1 protein and suppressing lung cancer progression. This novel mechanism provided a better insight into the pathogenesis of lung cancer and presented a better strategy for the treatment of lung cancer.