Microarray Identifies a Key Carcinogenic Circular RNA 0008594 That Is Related to Non-Small-Cell Lung Cancer Development and Lymph Node Metastasis and Promotes NSCLC Progression by Regulating the miR-760-Mediated PI3K/AKT and MEK/ERK Pathways

Circular RNA ATP9A Stimulates Non-small Cell Lung Cancer Progression via MicroRNA-582-3p/Ribosomal Protein Large P0 Axis and Activating Phosphatidylinositol 3-Kinase/Protein Kinase B Signaling Pathway

Circular RNAs (circRNAs), along with their pathogenic property in non-small cell lung cancer (NSCLC), require comprehensive analyses and explanations. The study is established with the purpose to elucidate the potential molecular mechanism of circATP9A in NSCLC. CircATP9A and microRNA (miR)-582-3p were evaluated by real-time quantitative polymerase chain reaction, and ribosomal protein large P0 (RPLP0), cleaved caspase-3, cleaved Ki-67, epithelial-to-mesenchymal transition (EMT)-associated proteins (N-cadherin and E-cadherin), and core proteins of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway were by Western blot. The processes of proliferation, apoptosis, migration, and invasion were measured by cell counting kit-8, 5-ethynyl-2'deoxyuridine, flow cytometry, and Transwell. Gene interaction was verified by RNA immunoprecipitation and dual luciferase reporter assay. CircATP9A and RPLP0 were abnormally highly expressed in both NSCLC tissues and cell lines, while miR-582-3p was abnormally low. Knockdown of circATP9A reduced NSCLC proliferation, invasion migration, and EMT and promoted apoptosis. This was further validated in nude mouse xenograft experiments. The inhibitory effect of knockdown of circATP9A on NSCLC was reversed by knockdown of miR-582-3p. In addition, the promoting effect of overexpression of circATP9A on NSCLC was reversed by knockdown of RPLP0. Mechanistically, circATP9A acted as a competitive endogenous RNA, sequestering miR-582-3p away from its target, which in turn modulated the expression of RPLP0. CircATP9A activated the miR-582-3p/RPLP0 axis by regulating the PI3K/Akt pathway in NSCLC cells. CircATP9A stimulates NSCLC progression via miR-582-3p/RPLP0 axis and PI3K/AKT cascade activation.

The postoperative prognosis of skip-N2 metastasis is favorable in small-cell lung carcinoma patients with pathological N2 classification: a propensity-score-adjusted retrospective multicenter study

BACKGROUND

The study on skip-N2 metastasis in small-cell lung cancer (SCLC) is lacking. Therefore, this study aimed to explore the prognostic significance of skip-N2 metastasis based on a multicenter cohort.

METHODS

We collected 176 SCLC patients with pathological categories T1-4N1-2M0 from four hospitals in China. Survival curves were drawn through the Kaplan-Meier method and compared by the log-rank test. The Cox regression method was used to calculate the hazard ratio (HR) and 95% confidence interval of the characteristics for cancer-specific survival (CSS). Two propensity-score methods were used to reduce the bias, including the inverse probability of treatment weighting (IPTW) and propensity-score matching (PSM).

RESULTS

This multicenter database included 64 pN1 patients, 63 non-skip-N2 cases, and 49 skip-N2 cases. Skip-N2 and the non-skip-N2 patients had gap CSS rates (skip-N2 no versus yes: 41.0% versus 62.0% for 1-year CSS, 32.0% versus 46.0% for 2-year CSS, and 20.0% versus 32.0% for 3-year CSS). After PSM, there were 32 pairs of patients to compare survival differences between N2 and skip-N2 diseases, and 34 pairs of patients to compare prognostic gaps between N1 and skip-N2 diseases, respectively. The results of IPTW and PSM both suggested that skip-N2 cases had better survival outcomes than the non-skip-N2 cases (IPTW-adjusted HR = 0.578; PSM-adjusted HR = 0.510; all log-rank p < 0.05). Besides, the above two analytic methods showed no difference in prognoses between pN1 and skip-N2 diseases (all log-rank p > 0.05).

CONCLUSIONS

Skip-N2 patients were confirmed to have a better prognosis than non-skip-N2 patients. Besides, there was no survival difference between pN1 and skip-N2 cases. Therefore, we propose that the next tumor-node-metastasis staging system needs to consider the situation of skip metastasis with lymph nodes in SCLC.

The emerging role of circular RNAs in drug resistance of non-small cell lung cancer

Due to the characteristics of aggressiveness and high risk of postoperative recurrence, non-small cell lung cancer (NSCLC) is a serious hazard to human health, accounting for 85% of all lung cancer cases. Drug therapies, including chemotherapy, targeted therapy and immunotherapy, are effective treatments for NSCLC in clinics. However, most patients ultimately develop drug resistance, which is also the leading cause of treatment failure in cancer. To date, the mechanisms of drug resistance have yet to be fully elucidated, thus original strategies are developed to overcome this issue. Emerging studies have illustrated that circular RNAs (circRNAs) participate in the generation of therapeutic resistance in NSCLC. CircRNAs mediate the modulations of immune cells, cytokines, autophagy, ferroptosis and metabolism in the tumor microenvironment (TME), which play essential roles in the generation of drug resistance of NSCLC. More importantly, circRNAs function as miRNAs sponges to affect specific signaling pathways, directly leading to the generation of drug resistance. Consequently, this review highlights the mechanisms underlying the relationship between circRNAs and drug resistance in NSCLC. Additionally, several therapeutic drugs associated with circRNAs are summarized, aiming to provide references for circRNAs serving as potential therapeutic targets in overcoming drug resistance in NSCLC.

Circ_0017639 facilitates proliferative, migratory, and invasive potential of non-small cell lung cancer (NSCLC) cells via PI3K/AKT signaling pathway

Non-small cell lung cancer (NSCLC) has increased morbidity and mortality rate worldwide. The current NSCLS therapies are associated with poor outcomes and need further improvement. CircRNAs were shown to regulate NSCLC progression. However, little is known re garding the functions and mechanisms of circ_0017639 in NSCLC, which requires further extensive studies. The circ_0017639 expression in NSCLC tissues and cell lines was evaluated via qRT-RCR. Moreover, using ectopic plasmid incorporation and shRNA assays, we analyzed the circ_0017639-mediated cellular proliferative, migratory and invasive processes in NSCLC cell lines, using CCK-8, EdU, and transwell assays. Furthermore, the core proteins (p-PI3K, PI3K, p-AKT, and AKT) levels of the PI3K/AKT signaling cascade were investigated via immunoblotting. Finally, we tested the functional role of circ_0017639 by examining its regulation of xenograft tumor growths in nude mice in vivo. Circ_0017639 expression was remarkably high in the NSCLC tissues and cell lines. The transfection experiments showed that circ_0017639 overexpression was able to promote proliferative, migratory, and invasive properties of NSCLC cells, while sh-circ_0017639 showed opposing effects. We further showed that circ_0017639 knockdown suppressed the cellular development via PI3K/AKT cascade inactivation. Additionally, in-vivo experiment in nude mice demonstrated that sh-circ_0017639 could reduce the tumor growth of NSCLC. Circ_0017639 may promote the development of NSCLC by accelerating NSCLC metastasis through stimulating the PI3K/AKT cascade.