Circ-METTL15 contributes to the proliferation, metastasis, immune escape and restrains apoptosis in lung cancer by regulating miR-1299/PDL1 axis.

BACKGROUND: Circular RNAs (circRNAs) are important regulators in the pathogenesis of lung cancer. The study aims to explore the function and mechanism of circRNA methyltransferase-like 15 (circ-METTL15) in lung cancer development. METHODS: The expression of circ-METTL15, miR-1299 and programmed death-ligand 1 (PDL1) were investigated by qRT-PCR assay. Cell viability, colony formation, cell proliferation and invasion were determined by MTT, colony formation, EDU incorporation and transwell assays, respectively. Cell apoptosis was attested by flow cytometry and TUNEL assays. Interferon-γ (IFN-γ) and Tumour Necrosis Factor-α (TNF-α) production were tested by enzyme-linked immunosorbent assay (ELISA), and the survival rate of cancer cells was assessed by cytotoxicity analysis. The protein expression was examined by western blot or immunohistochemistry (IHC) assay. The interaction between miR-1299 and circ-METTL15 or PDL1 was confirmed via dual-luciferase reporter assay. Xenograft models were established in mice to explore the role of circ-METTL15 in tumour growth in vivo. RESULTS: Circ-METTL15 was upregulated in lung cancer tissues and cells. Circ-METTL15 silencing suppressed cell proliferation, colony formation, invasion, immune escape and promoted cell apoptosis in lung cancer cells. Circ-METTL15 was a sponge of miR-1299, and it could exert regulatory function in lung cancer via miR-1299. Furthermore, PDL1 was a functional target of miR-1299, and miR-1299 inhibited lung cancer cell development via decreasing PDL1 expression. Moreover, circ-METTL15 controlled PDL1 expression by acting as a sponge of miR-1299. Besides, circ-METTL15 downregulation blocked lung cancer tumour growth in vivo by regulating the miR-1299/PDL1 axis. CONCLUSION: Circ-METTL15 promoted lung cancer malignant progression at least partly through modulating PDL1 by sponging miR-1299.

Long Noncoding RNA LINC01426 Sequesters microRNA-519d-5p to Promote Non-Small Cell Lung Cancer Progression by Increasing ETS1 Expression.

PURPOSE: Recent studies have identified important roles for long intergenic non-protein coding RNA 1426 (LINC01426) in glioma and clear cell renal cell carcinoma. The present study evaluated the expression profile of LINC01426 in non-small cell lung cancer (NSCLC) tissues and cell lines. Furthermore, the function of LINC01426 in NSCLC and the molecular mechanisms involved were extensively studied. METHODS: The abundance of LINC01426 in NSCLC tissues and cell lines was determined using quantitative reverse transcription-polymerase chain reaction. The cell counting kit-8 assay, flow cytometry, transwell experiments for migration and invasion, and xenograft tumor model were used to assess the function of LINC01426 in NSCLC cells. Mechanistic studies were performed using the luciferase reporter assay and RNA immunoprecipitation. RESULTS: Significant LINC01426 upregulation was observed in NSCLC tissues and cell lines. Silencing LINC01426 inhibited proliferation, migration, and invasion of NSCLC cells and facilitated cell apoptosis in vitro. Furthermore, interference of LINC01426 restricted tumor growth of NSCLC cells in vivo. In addition, LINC01426 showed the ability to directly bind to microRNA-519d-5p (miR-519d-5p) and act as a molecular sponge for miR-519d-5p in NSCLC cells. Furthermore, the ETS proto-oncogene 1 (ETS1) was identified as a direct target of miR-519d-5p and LINC01426 could indirectly upregulate ETS1 expression by sponging miR-519d-5p. Moreover, the cancer-inhibiting activities of LINC01426 knockdown in NSCLC cells were partially offset by miR-519d-5p inhibition. CONCLUSION: LINC01426 increases ETS1 expression by sequestering miR-519d-5p, thereby aggravating the malignant progression of NSCLC. The LINC01426/miR-519d-5p/ETS1 competing endogenous RNA pathway may provide a target for designing therapeutic agents for NSCLC treatment.

Comprehensive characterization and clinical impact of concomitant genomic alterations in EGFR-mutant NSCLCs treated with EGFR kinase inhibitors.

OBJECTIVES: Although the majority of epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients respond to EGFR tyrosine kinase inhibitors (TKIs), significant heterogeneity in clinical response is observed which might be attributed to the distinct sub-molecular characteristics. The present study aims to identify genetic alterations correlated with clinical outcomes and treatment response to different EGFR-TKI inhibitors. MATERIALS AND METHODS: We integrated the genomic data and clinical outcomes including progression-free survival (PFS) and overall survival (OS) in 179 patients with advanced EGFR-mutant NSCLC who were treated with EGFR-TKI as 1st line of treatment. RESULTS: We found that EGFR-mutant patients harboring concomitant TP53 mutation (OS: 21 vs. 40 months, P = 0.05), ERBB2 amplification (PFS: 6.1 vs. 12.5 months, P = 0.01) or FGF19 amplification (OS: 11.2 vs. 27.1 months, P = 0.01) were significantly associated with a poorer clinical prognosis after treated with 1st generation EGFR-TKI. In contrast, the presence of TP53 mutation did not affect the PFS nor OS of patients treated with 2nd generation EGFR-TKI. Furthermore, EGFR-mutant and TP53-wild type (WT) patients benefited more from a combinatorial treatment consisting of EGFR-TKI and bevacizumab comparing to EGFR-TKI as a single agent (PFS: 21.7 vs. 9.3 months, P < 0.01). Copy number variation (CNV) (PFS: 4.6 vs.9.4 months, p = 0.018) was identified as an unfavorable predictive factor to 3rd-generation TKI. We also revealed distinct resistance mechanisms associated with different EGFR-TKIs. CONCLUSION: Our study highlights the heterogeneity both in the primary molecular landscape and acquired alterations in EGFR-mutated NSCLCs, which might play a role in determining the clinical efficacy of EGFR-TKIs. We also revealed the differential prognostic role of TP53 mutation in patients treated with the 1st or 2nd generation of EGFR-TKI. Our study also suggests that EGFR-mutant and TP53-WT patients may benefit more from combinatorial treatment consisting of EGFR-TKI and bevacizumab, highlighting the importance of further stratifying EGFR-mutant patients.

Long noncoding RNA GAS6-AS2 sponges microRNA-493, thereby enhancing the malignant characteristics of breast cancer cells via upregulation of FUT4.

Long noncoding RNA (lncRNA) GAS6-AS2 serves as an oncogenic lncRNA in various types of human cancer. In this study, we attempted to examine the functions of GAS6-AS2 in breast cancer (BC) and explore the potential mechanisms involved. Reverse-transcription quantitative PCR was carried out to determine GAS6-AS2 expression in BC tissues and cell lines. Multiple functional experiments, including a Cell Counting Kit-8 assay, Transwell migration and invasion assays, and an in vivo nude-mouse xenograft experiment, were conducted to evaluate the effects of GAS6-AS2 in BC cells. GAS6-AS2 expression was high in BC tumors, manifesting a strong correlation with tumor size, lymph node metastasis, TNM stage, and shorter overall survival in patients with BC. A knockdown of GAS6-AS2 restricted BC cell proliferation, migration, and invasion in vitro and retarded tumor growth in vivo. With regard to its mechanism, GAS6-AS2 acted as a competing endogenous RNA that sponged microRNA-493 (miR-493), thereby increasing the expression of fucosyltransferase IV (FUT4). Either miR-493 inhibition or FUT4 upregulation abrogated the consequences of GAS6-AS2 knockdown in BC cells. These results revealed that GAS6-AS2 sponges miR-493 to enhance the malignant characteristics of BC in vitro and in vivo by increasing FUT4 expression. Thus, this lncRNA is an effective therapeutic target in BC and a promising diagnostic biomarker of this cancer.

Generalized emissivity inverse problem.

Inverse problems have recently drawn considerable attention from the physics community due to of potential widespread applications [K. Chadan and P. C. Sabatier, Inverse Problems in Quantum Scattering Theory, 2nd ed. (Springer Verlag, Berlin, 1989)]. An inverse emissivity problem that determines the emissivity g(nu) from measurements of only the total radiated power J(T) has recently been studied [Tao Wen, DengMing Ming, Xianxi Dai, Jixin Dai, and William E. Evenson, Phys. Rev. E 63, 045601(R) (2001)]. In this paper, a new type of generalized emissivity and transmissivity inverse (GETI) problem is proposed. The present problem differs from our previous work on inverse problems by allowing the unknown (emissivity) function g(nu) to be temperature dependent as well as frequency dependent. Based on published experimental information, we have developed an exact solution formula for this GETI problem. A universal function set suggested for numerical calculation is shown to be robust, making this inversion method practical and convenient for realistic calculations.