Stathmin 1 (STMN1), a major microtubule-depolymerizing protein, is involved in cell cycle progression and cell motility. However, the clinical significance of STMN1 expression in non-small cell lung cancer (NSCLC) has not been determined. The expression pattern of STMN1 mRNA was analyzed by quantitative real-time PCR (qRT-PCR) in 37 cases of NSCLC and in the corresponding non-tumor tissue samples. Furthermore, immunohistochemistry was performed to detect STMN1 protein expression in 113 primary NSCLC tissues. The functional role of STMN1 in lung cancer cell lines was evaluated by small interfering RNA-mediated depletion followed by analyses of cell proliferation and invasion. We found that the STMN1 mRNA and protein levels in NSCLC tissues were significantly higher than those in the corresponding non-tumor tissues (P<0.001). In addition, increased STMN1 expression was correlated with poor tumor differentiation (P<0.001), large tumor size (P=0.022), advanced N stage (P=0.033), and advanced TNM stage (P<0.001). Kaplan–Meier analysis indicates that NSCLC patients with higher STMN1 expression showed significantly worse survival. Moreover, multivariate analysis indicates that higher STMN1 protein expression was an independent prognostic factor of disease-specific survival (HR 2.247, 95%CI 1.320-3.825, P=0.003). Finally, the knockdown of STMN1 in lung cancer cells resulted in a decrease in cellular proliferation and invasion. Our findings suggest that STMN1 may have an important role in NSCLC progression and could serve as a potential prognostic marker for patients with NSCLC.

Long non-coding RNA UCA1 is a predictive biomarker of cancer

Background: Small cell lung cancer (SCLC) is the most deadly and aggressive type of primary lung cancer, with the 5-year survival rate lower than 5%. The FDA has approved arsenic trioxide (As₂O₃) for acute promyelocytic leukemia (APL) treatment. However, its role in SCLC-derived cancer stem cells (CSCs) remains largely unknown. Methods: CSCs were enriched from SCLC cell lines by culturing them as spheres in conditioned serum-free medium. Then, qPCR, western blot, serial passage, limiting dilution, Transwell, and tumorigenesis assay were performed to verify the cells’ stem phenotypic characteristics. Anticancer efficiency of As₂O₃ was assessed in these cells using CCK8, colony formation, sphere formation, flow cytometry, qPCR, western blot analysis in vitro, and tumor growth curve, immunofluorescence, and TUNEL staining analyses in vivo. Results: The fifth-passage SCLC spheres showed a potent self-renewal capacity, higher clonal formation efficiency (CFE), SOX2, c-Myc, NANOG, and OCT4 levels, and invasion ability, and stronger tumorigenesis capacity than the parental SCLC cells, indicating that the SCLC sphere cells displayed CSC features. As₂O₃ inhibited the proliferation, clonality and sphere forming ability of SCLC-derived CSCs and suppressed the tumor growth of CSCs-derived xenograft tumors. As₂O₃ induced apoptosis and downregulation of SOX2 and c-Myc in vitro and in xenografts. Besides, SOX2 knockdown suppressed SCLC-derived CSCs to self-renew and induced apoptosis. Mechanistically, expression of GLI1 (a key transcription factor of Hedgehog pathway) and its downstream genes increased in SCLC-derived CSCs, compared to the parental cells. As₂O₃ dramatically downregulated GLI1 and its downstream genes in vitro and in vivo. The GLI inhibitor (GANT-61) recapitulated and enhanced the effects of As₂O₃ on SCLC-derived CSCs, including growth suppression, apoptosis induction, and GLI1, SOX2 and c-Myc downregulation. Conclusions: Altogether, As₂O₃ effectively suppressed SCLC-derived CSCs growth by downregulating stem cell-maintenance factors and inducing apoptosis. These effects are mediated at least partly via the Hedgehog signaling blockade.

Bradykinin inhibits oxidative stress-induced senescence of endothelial progenitor cells through the B2R/AKT/RB and B2R/EGFR/RB signal pathways