Objective
: Increasing evidence suggested that dysregulated small nucleolar RNAs (snoRNAs) were involved in tumor development. The roles of snoRNA 71A (SNORA71A) in the progression of non-small cell lung cancer (NSCLC) remained unclear.
Methods
: Dataset GSE19188 from Gene Expression Omnibus (GEO) database was downloaded to detect the expression levels of SNORA71A in NSCLC tissues. The biological significance of SNORA71A was explored by loss-of-function analysis both in vitro and in vivo.
Results
: SNORA71A was overexpressed in NSCLC tissues compared with normal tissues, and upregulated SNORA71A was significantly associated with worse survival of NSCLC patients. Knockdown of SNORA71A suppressed proliferation of both A549 and PC9 cells, and induced G0/G1 phase arrest. Knockdown of SNORA71A also suppressed xenograft tumor growth in mice. In addition, knockdown of SNORA71A inhibited cell invasion and migration and suppressed epithelial-mesenchymal transition. Furthermore, downregulated SNORA71A decreased the phosphorylation of MEK and ERK1/2 in the MAPK/ERK signal pathway.
Conclusion
: SNORA71A functions as an oncogene in NSCLC and may serve as a therapeutic target and promising prognostic biomarker of NSCLC.
The production of nitric oxide (NO) is a key feature of immunosuppressive myeloid cells, which impair T cell activation and proliferation via reversibly blocking interleukin-2 receptor signaling. NO is mainly produced from L-arginine by inducible NO synthase (iNOS). Moreover, L-arginine is an essential element for T cell proliferation and behaviors. Impaired T cell function further inhibits anti-tumor immunity and promotes tumor progression. Previous studies indicated that radiotherapy activated anti-tumor immune responses in multiple tumors. However, myeloid-derived cells in the tumor microenvironment may neutralize these responses. We hypothesized that iNOS, as an important regulator of the immunosuppressive effects in myeloid-derived cells, mediated radiation resistance of cancer cells. In this study, we used 1400W dihydrochloride, a potent small-molecule inhibitor of iNOS, to explore the regulatory roles of NO in anti-tumor immunity. Radiotherapy and iNOS inhibition by 1400W collaboratively suppressed tumor growth and increased survival time, as well as increased tumor-infiltrating CD8 + T cells and specific inflammatory cytokine levels, in both lung and breast cancer cells in vivo. Our results also suggested that myeloid cell-mediated inhibition of T cell proliferation was effectively counteracted by radiation and 1400W-mediated NO blockade in vitro. Thus, these results demonstrated that iNOS was an important regulator of radiotherapy-induced antitumor immune responses. The combination of radiotherapy with iNOS blockade might be an effective therapy to improve the response of tumors to clinical radiation.
With the advancement of nanotechnology, various nanocomposites have been applied in the diagnostics and treatment of cancer. We synthetized FePt nanoparticles which were assembled on the surface of graphene oxide (GO). These novel FePt/GO nanosheets simultaneously act as a chemotherapy drug and enhance radiosensitivity. In this study, transmission electron microscope, dynamic light scattering, X-ray photoelectron spectroscope and Fourier transform infrared spectroscopy were used to characterize surface morphology and chemical composition of FePt/GO nanosheets (NSs). Their cytotoxicity in various cancer and normal cells was evaluated by cell counting kit-8 assay, and their effects on radiosensitization were determined by colony formation assay. To explore the underlying mechanisms, we measured the intracellular reactive oxygen species levels and autophagy formation. Monodansylcadaverine-staining, Western Blotting and ultrastructure analysis were utilized to assess autophagy. The results demonstrated that FePt/GO NSs not only selectively suppressed the proliferation of cancer cells, but also increased their radiosensitization. Moreover, FePt/GO NSs induced autophagy, which might result in promoted sensibilization of radiotherapy. In conclusion, with good safety and efficacy, FePt/GO NSs are safe and effective to suppress proliferation, enhance radiosensitization and induce autophagy of human non-small cell lung cancer cells. They are potential for the treatment of lung cancer.
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