LINC01006 regulates the proliferation, migration and invasion of hepatocellular carcinoma cells through regulating miR-433-3p/CBX3 axis

MALAT1 DEREPRESSES MIR-433-3P-MEDIATED RPTOR SUPPRESSION TO IMPAIR AUTOPHAGY AND DRIVE PYROPTOSIS IN ENDOTOXEMIA

ABSTRACT

Objective: Autophagy elevation in endotoxemia plays a protective role by negatively regulating the pyroptosis of vascular endothelial cells, but the molecular mechanisms are still poorly understood. The present study aimed to identify the mechanism underlying autophagy and pyroptosis in endotoxemia. Methods: Bioinformatics analysis and whole-gene transcriptome sequencing prediction were used to identify the endotoxemia-related lncRNA-miRNA-mRNA axis of interest. Human umbilical vein endothelial cells (HUVECs) were activated by lipopolysaccharide (LPS) to mimic the inflammatory environment encountered in endotoxemia. Autophagy and pyroptosis of LPS-treated HUVECs were assessed in response to the knockdown of MALAT1 (metastasis-associated lung adenocarcinoma transcript 1)/miR-433-3p (miRNA-433-3p)/RPTOR (regulatory-associated protein of mTOR). The binding affinity of MALAT1, miR-433-3p, and RPTOR was detected by RNA pull-down and luciferase activity assays. The endothelial cell-specific RPTOR knockout mice were developed and rendered septic using LPS induction to verify the role of RPTOR in autophagy, pyroptosis, and inflammatory response in vivo . Results: The in vitro experiments indicated that LPS could stimulate HUVECs to highly express RPTOR, and its knockdown enhanced cellular autophagy and restricted pyroptosis to curb inflammatory responses. Mechanically, MALAT1 is competitively bound to miR-433-3p to release RPTOR expression, thereby promoting pyroptosis and aggravating endotoxemia. In vivo experiments further confirmed that the knockdown of RPTOR activated autophagy and curtailed pyroptosis in septic mice. Conclusion: MALAT1 is highly expressed in endotoxemia. MALAT1 promotes RPTOR expression by competitively absorbing miR-433-3p, inhibits LPS-activated HUVEC cell autophagy, promotes cell death, enhances LPS-induced inflammatory activation of vascular endothelial cells, and ultimately promotes the progression of endotoxemia.

c-MYC/METTL3/LINC01006 positive feedback loop promotes migration, invasion and proliferation of non-small cell lung cancer

BACKGROUND

This study aims to clarify the N6-methyladenosine (m6A) modification of LINC01006, which is involved in migration, invasion and proliferation of non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

LINC01006 and METTL3 expressions were analyzed in TCGA-LUAD cohort. Colony formation assay, wound-healing assay and transwell assay were performed to evaluate the ability of colony formation, migration and invasion. Q-PCR and western blot analysis determined gene expressions. M6A-RNA immunoprecipitation and m6A quantification assay were used to evaluate m6A modification. qChIP assay was used to validate transcriptional target. Luciferase assay validated the miRNA targets and transcriptional targets. In-situ xenograft model were included to evaluate tumor proliferation in vivo.

RESULTS

LINC01006 and METTL3 expressions were elevated in NSCLC cells and tissues. LINC01006 promoted the migration and invasion of NSCLC via epithelial - mesenchymal transition (EMT). The expression of LINC01006 was positively correlated to the expression of METTL3. METTL3 promoted tumor formation and proliferation in the in-situ xenograft model of NSCLC. The expression of LINC01006 was increased by METTL3 via m6A modification. c-MYC directly induced METTL3. Both c-MYC and LINC01006 were commonly targeted by miR-34a/b/c and miR-2682, and thereby c-MYC/METTL3/LINC01006 formed a positive feedback loop through miRNA targets in NSCLC.

CONCLUSIONS

LINC01006 is an oncogenic lncRNA, which induces migration, invasion and proliferation of NSCLC. METTL3 increases LINC01006 expression through stabilizing LINC01006 mRNA. c-MYC, as a transcription factor, activates METTL3, which results in an elevated level of LINC01006. c-MYC, METTL3 and LINC01006 form a positive feedback loop through multiple miRNA targets in NSCLC.

PSMC4 promotes prostate carcinoma progression by regulating the CBX3-EGFR-PI3K-AKT-mTOR pathway

Proteasome 26S subunit ATPase 4 (PSMC4) could regulate cancer progression. However, the function of PSMC4 in prostate carcinoma (PCa) progression requires further clarification. In the study, PSMC4 and chromobox 3 (CBX3) levels were verified by TCGA data and tissue microarrays. Cell counting kit-8, cell apoptosis, cell cycle, wound healing, transwell and xenograft tumour model assays were performed to verify biological functions of PSMC4 in PCa. RNA-seq, PCR, western blotting and co-IP assays were performed to verify the mechanism of PSMC4. Results showed that PSMC4 level was significantly increased in PCa tissues, and patients with PCa with a high PSMC4 level exhibited shorter overall survival. PSMC4 knockdown markedly inhibited cell proliferation, cell cycle and migration in vitro and in vivo, and significantly promoted cell apoptosis. Then further study revealed that CBX3 was a downstream target of PSMC4. PSMC4 knockdown markedly reduced CBX3 level, and inhibited PI3K-AKT-mTOR signalling. CBX3 overexpression markedly promoted epidermal growth factor receptor (EGFR) level. Finally, PSMC4 overexpression showed reverse effect in DU145 cells, and the effects of PSMC4 overexpression on cell proliferation, migration and clonal formation were rescued by the CBX3 knockdown, and regulated EGFR-PI3K-AKT-mTOR signalling. In conclusion, PSMC4 could regulate the PCa progression by mediating the CBX3-EGFR-PI3K-AKT-mTOR pathway. These findings provided a new target for PCa treatment.

Knockdown of circEXOC6 inhibits cell progression and glycolysis by sponging miR-433-3p and mediating FZD6 in glioma

BACKGROUND

The effect of circular RNA in many human cancers is widely studied. Nevertheless, their specific biological functions and mechanisms in glioma remain unclear.

METHODS

CircEXOC6, miR-433-3p, and frizzled class receptor 6 (FZD6) mRNA expression levels were measured by quantitative reverse transcription polymerase chain reaction assay. Cell proliferation, migration, invasion, apoptosis, and angiogenesis were tested by colony formation, cell-light 5-ethynyl-2'-deoxyuridine, transwell, and tube formation assays, respectively. Moreover, glucose consumption and lactate production were calculated to evaluate the glycolytic metabolism using the respective kits. Western blot assay was carried out to measure the protein levels of apoptotic markers (Bcl-2 and Bax), glycolytic markers (HK2 and GLUT1), and FZD6. The targeted relationship of miR-433-3p and circEXOC6 or FZD6 was verified by dual-luciferase reporter or RNA immunoprecipitation assays. In vivo, xenograft and immunohistochemistry assay was conducted to discriminate the effect of circEXOC6.

RESULTS

CircEXOC6 and FZD6 were highly expressed, while miR-433-3p was significantly lowly expressed in glioma tissues or cells. Deficiency of circEXOC6 inhibited cell proliferation, migration, invasion, angiogenesis, and glycolysis, and triggered cell apoptosis ratio in glioma; simultaneously, it could block the growth of tumor in vivo. In addition, miR-433-3p was a target of circEXOC6, and downregulated miR-433-3p could partly weaken the inhibitory effect of circEXOC6 deficiency. Besides, miR-433-3p enrichment inhibited cell progression and glycolysis in glioma, and the effect was reversed by overexpression of FZD6.

CONCLUSION

Deletion of circEXOC6 restrained cell progression and glycolysis by sponging miR-433-3p and interacting with FZD6, which might provide an underlying target for glioma treatment.

The role of MiRNA ‐433 in malignant tumors of digestive tract as tumor suppressor

Background

MicroRNAs (miRNAs) are a class of short non‐coding RNAs with a length of approximate 22 nuclei acids that can be expressed both as an oncogene and tumor suppressor gene in human cancers. MiRNAs can participate in the post‐ transcriptional regulation of gene expression, and regulate the several cancer‐related processes, including proliferation, apoptosis, metastasis, etc.

Recent findings

Expression of miRNA‐433 has been reported to vary in different tumors and affected by various factors. We have summarized the different previous studies and found that miRNA‐433 can significantly inhibit the growth of the cancer cells not only in malignant tumors of the digestive tract, but also in lung cancer, breast cancer, cervical cancer, ovarian cancer, bladder cancer, renal carcinoma, glioma, retinoblastoma and osteosarcoma.

Conclusion

When the expression of miRNA‐433 was up‐regulated, the proliferation, metastasis and invasion abilities of the malignant tumor cells were significantly inhibited. At the same time, the potential mechanisms through which miRNA‐433 can suppress the growth and metastasis of the cancer cells were found to be basically the same, and involved modulation of the specific signaling pathways or target genes in the malignant tumors. Overall, it can be concluded that miRNA‐433 can serve as potential and valuable therapeutic target.

MALAT1-miRNAs network regulate thymidylate synthase and affect 5FU-based chemotherapy

Background

The active metabolite of 5-Fluorouracil (5FU), used in the treatment of several types of cancer, acts by inhibiting the thymidylate synthase encoded by the TYMS gene, which catalyzes the rate-limiting step in DNA replication. The major failure of 5FU-based cancer therapy is the development of drug resistance. High levels of TYMS-encoded protein in cancerous tissues are predictive of poor response to 5FU treatment. Expression of TYMS is regulated by various mechanisms, including involving non-coding RNAs, both miRNAs and long non-coding RNAs (lncRNAs).

Aim

To delineate the miRNAs and lncRNAs network regulating the level of TYMS-encoded protein.

Main body

Several miRNAs targeting TYMS mRNA have been identified in colon cancers, the levels of which can be regulated to varying degrees by lncRNAs. Due to their regulation by the MALAT1 lncRNA, these miRNAs can be divided into three groups: (1) miR-197-3p, miR-203a-3p, miR-375-3p which are downregulated by MALAT1 as confirmed experimentally and the levels of these miRNAs are actually reduced in colon and gastric cancers; (2) miR-140-3p, miR-330-3p that could potentially interact with MALAT1, but not yet supported by experimental results; (3) miR-192-5p, miR-215-5p whose seed sequences do not recognize complementary response elements within MALAT1. Considering the putative MALAT1-miRNAs interaction network, attention is drawn to the potential positive feedback loop causing increased expression of MALAT1 in colon cancer and hepatocellular carcinoma, where YAP1 acts as a transcriptional co-factor which, by binding to the TCF4 transcription factor/ β-catenin complex, may increase the activation of the MALAT1 gene whereas the MALAT1 lncRNA can inhibit miR-375-3p which in turn targets YAP1 mRNA.

Conclusion

The network of non-coding RNAs may reduce the sensitivity of cancer cells to 5FU treatment by upregulating the level of thymidylate synthase.

Genomic instability genes in lung and colon adenocarcinoma indicate organ specificity of transcriptomic impact on Copy Number Alterations

Genomic instability (GI) in cancer facilitates cancer evolution and is an exploitable target for therapy purposes. However, specific genes involved in cancer GI remain elusive. Causal genes for GI via expressions have not been comprehensively identified in colorectal cancers (CRCs). To fill the gap in knowledge, we developed a data mining strategy (Gene Expression to Copy Number Alterations; "GE-CNA"). Here we applied the GE-CNA approach to 592 TCGA CRC datasets, and identified 500 genes whose expression levels associate with CNA. Among these, 18 were survival-critical (i.e., expression levels correlate with significant differences in patients' survival). Comparison with previous results indicated striking differences between lung adenocarcinoma and CRC: (a) less involvement of overexpression of mitotic genes in generating genomic instability in the colon and (b) the presence of CNA-suppressing pathways, including immune-surveillance, was only partly similar to those in the lung. Following 13 genes (TIGD6, TMED6, APOBEC3D, EP400NL, B3GNT4, ZNF683, FOXD4, FOXD4L1, PKIB, DDB2, MT1G, CLCN3, CAPS) were evaluated as potential drug development targets (hazard ratio [> 1.3 or < 0.5]). Identification of specific CRC genomic instability genes enables researchers to develop GI targeting approach. The new results suggest that the "targeting genomic instability and/or aneuploidy" approach must be tailored for specific organs.

Construction of a ceRNA Network and Comprehensive Analysis of lncRNA in Hepatocellular Carcinoma

To explore the RNA biomolecular marker associated with hepatocellular carcinoma (HCC) prognosis, we constructed a regulatory network of competitive endogenous RNAs (ceRNAs), which provides favorable conditions for the early diagnosis, prognostic monitoring, and personalized treatment of HCC. In this study, the differentially expressed genes (DEGs) of patients with HCC were obtained from the Gene Expression Omnibus. We identified 574 upregulated genes and 274 downregulated genes relevant to HCC occurrence (p < 0.05). Subsequently, we constructed the protein−protein interaction (PPI) network using these DEGs and identified the hub genes from the PPI. We then determined the expression and prognostic values of the hub genes from the GEPIA and Kaplan−Meier plotter databases. After the upstream microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) were respectively identified by miRTarBase and miRNet, we validated the expression of the key miRNAs in the serum using qPCR experiments. Moreover, we identified a two-lncRNA (LINC01184 and ADORA2A-AS1) signature from the upstream lncRNA that effectively predicted overall survival and had promotive effects for HCC. To verify the clinical significance of the signature, we validated the expression of the lncRNA in HCC tissues. Finally, we discovered and identified four mRNAs, four miRNAs, and five lncRNAs associated with the prognosis of HCC and constructed a new ceRNA regulatory network, which will be beneficial for the accurate diagnosis and treatment of HCC.

ASPM May be Related to the Malignant Progression of Hepatitis B and is Associated With a Poor Prognosis of Hepatocellular Carcinoma

Background: Hepatitis B virus (HBV) is a causative agent of hepatocellular carcinoma (HCC). Until now, the mechanism behind the progress of hepatitis B fibrosis to HCC remains largely unknown. This study aims to examine the candidate biomarkers and pathways involved in HBV-associated HCC.

Methods: Gene expression profiles were retrieved from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using the GEO2R tool after which functional enrichment analysis, protein-protein interaction (PPI) analysis, genetic alteration analysis, prognostic analysis, immune infiltration analysis, co-expression genes prediction, and miRNA-gene network construction, and pathway correlation analysis were performed.

Results: 22 hub genes were identified, which were all highly expressed in HCC, and overexpression of these genes was all associated with significantly worse survival in HCC patients. More significantly, ASPM also showed increased expression levels in non-tumor tissues with advanced liver fibrosis. With the progression of liver fibrosis and the closer tumor center of HCC, the higher expression of ASPM was identified. ASPM was considered to be the most promising biomarker because it also showed the highest genetic alteration frequency among the hub genes and the expression level of ASPM in HBV (+) HCC tissues was significantly higher than that in HBV (-) HCC tissues. Also, the infiltration levels of B cells, CD8⁺ T cells, CD4⁺ T cells, macrophages, neutrophils, and dendritic cells were all positively correlated with the expression of ASPM.

Conclusion: These findings may help in the development of strategies and candidate drugs for the treatment of HBV-related HCC and improve the effectiveness of personalized treatment in the future. ASPM was upregulated in both hepatitis B cirrhosis and HCC and could be a potential predicting biomarker.

LINC-DUBR Suppresses Malignant Progression of Ovarian Cancer by Downregulating miR-107 to Induce SMAC Expression

Background

LINC-DUBR may be a potential therapeutic target in ovarian cancer (OC). The purpose of this research was to explore the impact of miR-107 on the tumorigenicity of OC and its underlying molecular mechanisms.

Methods

RT-qPCR was adopted to measure the expression of LINC-DUBR and miR-107 in ovarian cancer tissues and cells. CCK-8 assays and transwell chamber assays were conducted to evaluate the impacts of LINC-DUBR and miR-107 on the proliferation and invasion of human ovarian cancer cells (SKOV3). In addition, we determined the relationship between LINC-DUBR, miR-107, and SMAC using TargetScan and luciferase reporter assay. The protein expression of SMAC was determined by western blot.

Results

Compared with normal tissues and cells, LINC-DUBR was downregulated and miR-107 was highly expressed in ovarian cancer tissues and cell lines. Overexpression of LINC-DUBR inhibited the cell proliferation and invasive ability in OC cells SKOV3. The luciferase reporter assay proved overexpression of LINC-DUBR repressed cells proliferation and invasion via binding to miR-107 in ovarian cancer. In addition, we found that SMAC was downregulated directly by miR-107 in ovarian cancer. miR-107 mimic significantly increased cell proliferation and invasiveness of SKOV3, while overexpressed SMAC eliminated this effect. Furthermore, miR-107 could regulate the XIAP/caspase-3 signaling pathway in ovarian cancer by targeting SMAC.

Conclusion

LINC-DUBR suppressed malignant progression of ovarian cancer by downregulating miR-107 to induce SMAC expression and involving in the XIAP/caspase-3 signaling pathway.