Targeting the miR-6734-3p/ZEB2 axis hampers development of non-small cell lung cancer (NSCLC) and increases susceptibility of cancer cells to cisplatin treatment

Comparison of salivary MicroRNA-6734, microRNA-3123 and microRNA-4483 expression in smoker and nonsmoker patients: a case control study

BACKGROUND

Tobacco is a major risk factor in oral diseases. Considering the important role of expression miRNA molecules in different diseases, the present study aimed to compare the expression of salivary miRNA-6734, miRNA-3123 and miRNA-4483 in smoker and non-smoker peoples.

METHODS

In this case-control study, salivary samples were obtained from 30 smoker's patients and 27 healthy nonsmokers and matched in term of age and sex. RNA was extracted in salivary samples and gene expression was evaluated in all samples. Statistical analysis of data was performed using T and chi-square tests by SPSS (Ver. 16) software at a significant level of less than 0.05.

RESULTS

The results of this study showed that the expression level of miRNA-3123 and miRNA-4483 in smokers group was 2.8 and 3.2, respectively, which was increased compared to non-smokers with expression level of 1 (P<0.01). There was a significant decrease in the expression rate of miRNA-6734 in smokers (0.6%) compared to non-smokers (P<0.05).

CONCLUSIONS

Based on the results of this study, considering the increasing miRNA-4483 and miRNA-3123 level, as well as the reducing miRNA-6734 level in smokers compared to non-smokers, it seems that evaluation of these two miRNAs as indicator for diagnosis and determination of prognosis of oral diseases associated with smoking can be used.

LncRNA CASC19: a novel oncogene involved in human cancer

Multiple studies have shown that long non-coding RNAs (lncRNAs) play an important role in the occurrence and development of diverse cancers. Cancer susceptibility candidate 19 (CASC19), encoded by chromosome 8q24.21, is a newly discovered lncRNA that contains 324 nucleotides. CASC19 has been found to be significantly overexpressed in different human cancers, such as non-small cell lung carcinoma, gastric cancer, colorectal cancer, pancreatic cancer, clear cell renal cell carcinoma, glioma, cervical cancer, and nasopharyngeal carcinoma. Moreover, dysregulation of CASC19 was closely associated with clinicopathological parameters and cancer progression. CASC19 regulates a variety of cell phenotypes, including cell proliferation, apoptosis, cell cycle, migration, invasion, epithelial-mesenchymal transition, autophagy, and therapeutic resistance. In this study, we review recent studies on the characteristics and biological function of CASC19, as well as its role in human cancers. These findings suggest that CASC19 may be both a reliable biomarker and a potential therapeutic target in cancers.

Eukaryotic initiation factor 5A2 mediates hypoxia-induced autophagy and cisplatin resistance

Hypoxia-induced cisplatin resistance is a major challenge during non-small cell lung cancer (NSCLC) treatment. Based on previous studies, we further explored the effect of eukaryotic initiation factor 5A2 (eIF5A2) in hypoxia-induced cisplatin resistance. In this study, we found that autophagy and cisplatin resistance were increased under hypoxic conditions in three different NSCLC cell lines. Compared with that under normoxic conditions, dramatic upregulation of eIF5A2 and hypoxia inducible factor 1 subunit alpha (HIF-1α) levels were detected under hypoxia exposure. Small interfering RNA silencing of HIF-1α resulted in decreased expression of eIF5A2, indicating that eIF5A2 acts downstream of HIF-1α. In addition, the expression of eIF5A2 was significantly higher in NSCLC tumors compared with that in normal tissues. RNA silencing-mediated downregulation of eIF5A2 decreased hypoxia-induced autophagy, thereby reducing hypoxia-induced cisplatin resistance in NSCLC cells. The roles of eIF5A2 in cisplatin resistance were further validated in vivo. Combined treatment using eIF5A2-targeted downregulation together with cisplatin significantly inhibited tumor growth compared with cisplatin alone in the subcutaneous mouse model. In conclusions, eIF5A2 overexpression is involved in hypoxia-induced autophagy during cisplatin resistance. We suggest that a combination of eIF5A2 targeted therapy and cisplatin chemotherapy is probably an effective strategy to reverse hypoxia-induced cisplatin resistance and inhibit NSCLC development.

Circular RNA circ_0002360 regulates the Taxol resistance and malignant behaviors of Taxol-resistant non-small cell lung cancer cells by microRNA-585-3p-dependent modulation of G protein regulated inducer of neurite outgrowth 1

Drug resistance has become the major obstacle for the treatment of non-small cell lung cancer (NSCLC). Circular RNAs (circRNAs) are tightly linked to the development of drug resistance of NSCLC. Herein, we tested the function of circ_0002360 in the Taxol resistance of NSCLC. Circ_0002360, microRNA (miR)-585-3p and G protein regulated inducer of neurite outgrowth 1 (GPRIN1) were quantified by quantitative real-time PCR (qRT-PCR). To identify the circular structure of circ_0002360, RNase R digestion was applied. To detect cell proliferation, colony formation and 5-ethynyl-2’-deoxyuridine (EdU) assays were used. For assessment of cell apoptosis, flow cytometry was adopted. For motility and invasion analyses, transwell assay was employed. Our data showed that circ_0002360 was mainly located in the cytoplasm and was highly expressed in the Taxol-resistant NSCLC. Silencing of circ_0002360 inhibited cell Taxol resistance, proliferation, motility, and invasiveness and induced apoptosis in vitro. MiR-585-3p was underexpressed in Taxol-resistant NSCLC and was targeted by circ_0002360. MiR-585-3p knockdown alleviated the influence of circ_0002360 silence on Taxol-resistant cells. GPRIN1 was directly targeted by miR-585-3p. The influence of miR-585-3p on cell Taxol resistance and functional behaviors was reversed by GPRIN1 overexpression. Moreover, circ_0002360 modulated GPRIN1 through miR-585-3p. Additionally, silencing of circ_0002360 weakened the growth of xenografts in vivo. Our study demonstrated that silencing of circ_0002360 enhanced the Taxol sensitivity and suppressed the malignant behaviors of Taxol-resistant NSCLC cells by miR-585-3p/GPRIN1 axis, providing novel targets for improving the anti-tumor efficacy of Taxol in NSCLC.

Knock-down of microRNA miR-556-5p increases cisplatin-sensitivity in non-small cell lung cancer (NSCLC) via activating NLR family pyrin domain containing 3 (NLRP3)-mediated pyroptotic cell death

MicroRNAs (miRNAs) are small non-coding RNAs that are closely associated with cancer progression and drug resistance, however, up until now, the involvement of miR-556-5p in regulating cisplatin-sensitivity in non-small cell lung cancer (NSCLC) has not been studied. In the present study, we found that miR-556-5p was significantly upregulated in the cisplatin-resistant NSCLC (CR-NSCLC) patients’ tissues and cells, instead of the corresponding cisplatin-sensitive NSCLC (CS-NSCLC) tissues and cells. Further experiments validated that knock-down of miR-556-5p suppressed cell viability and tumorigenesis, and induced cell apoptosis in the cisplatin-treated CR-NSCLC cells, and conversely, upregulation of miR-556-5p increased cisplatin-resistance in CS-NSCLC cells. Interestingly, miR-556-5p ablation triggered pyroptotic cell death in cisplatin-treated CR-NSCLC cells via upregulating NLRP3, and the promoting effects of miR-556-5p silence on cisplatin-sensitivity in CR-NSCLC cells were abrogated by both cell pyroptosis inhibitor NSA and NLRP3 downregulation. Taken together, this study firstly evidenced that induction of NLRP3-mediated cell pyroptosis by miR-556-5p downregulation was effective to increase cisplatin-sensitivity in NSCLC, which provided new therapy strategies to overcome chemo-resistance for NSCLC patients in clinic.

Long non-coding RNA MCM3AP antisense RNA 1 promotes non-small cell lung cancer progression through targeting microRNA-195-5p

Lung cancer (LC) ranks first among all causes of cancer-related death, with non-small cell lung cancer (NSCLC) taking up 85% of lung cancer cases. Although lncRNA MCM3AP antisense RNA 1 (MCM3AP-AS1) has been reported to be an oncogenic factor in NSCLC, its detailed mechanism in NSCLC is unknown. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine MCM3AP-AS1, microRNA (miR)-195-5p and E2F transcription factor 3 (E2F3) mRNA expressions in NSCLC tissues and cells. Western blot was utilized to determine the expression levels of E2F3, BCL2-associated X protein (Bax), B-cell lymphoma-2 (Bcl-2), E-cadherin and N-cadherin. CCK-8 and Transwell assays were conducted to examine cell proliferation, migration and invasion, respectively. Dual-luciferase reporter assay and RNA immunoprecipitation experiments were used to determine the regulatory relationships between MCM3AP-AS1 and miR-195-5p, and miR-195-5p and E2F3. We demonstrated that MCM3AP-AS1 was overexpressed in NSCLC tissues and cells, and MCM3AP-AS1 overexpression accelerated the proliferation, migration and invasion of NSCLC cells. In addition, MCM3AP-AS1 overexpression markedly up-modulated Bcl-2 expression and repressed Bax expression; MCM3AP-AS1 overexpression also significantly up-regulated N-cadherin expression and suppressed E-cadherin expression in NSCLC cells. What is more, in NSCLC cells, miR-195-5p was a target of MCM3AP-AS1, and the latter worked as a molecular sponge for miR-195-5p to regulate E2F3 expression. Collectively, MCM3AP-AS1, serving as a competitive endogenous RNA (ceRNA) to regulate miR-195-5p/E2F3 axis, promotes NSCLC progression, which is a promising therapeutic target for NSCLC.