Ming Yang

Accumulated evidence demonstrated that long non-coding RNAs (lncRNAs) play a pivotal role in tumorigenesis. However, it is still largely unknown how these lncRNAs were regulated by small ncRNAs, such as microRNAs (miRNAs), at the post-transcriptional level. We here use lncRNA HOTTIP as an example to study how miRNAs impact lncRNAs expression and its biological significance in hepatocellular carcinoma (HCC). LncRNA HOTTIP is a vital oncogene in HCC, one of the deadliest cancers worldwide. In the current study, we identified miR-192 and miR-204 as two microRNAs (miRNAs) suppressing HOTTIP expression via the Argonaute 2 (AGO2)-mediated RNA interference (RNAi) pathway in HCC. Interaction between miR-192 or miR-204 and HOTTIP were further confirmed using dual luciferase reporter gene assays. Consistent with this notion, a significant negative correlation between these miRNAs and HOTTIP exists in HCC tissue specimens. Interestingly, the dysregulation of the three ncRNAs was associated with overall survival of HCC patients. In addition, the posttranscriptional silencing of HOTTIP by miR-192, miR-204 or HOTTIP siRNAs could significantly suppress viability of HCC cells. On the contrary, antagonizing endogenous miR-192 or miR-204 led to increased HOTTIP expression and stimulated cell proliferation. In vivo mouse xenograft model also support the tumor suppressor role of both miRNAs. Besides the known targets (multiple 5’ end HOX A genes, i.e. HOXA13), glutaminase (GLS1) was identified as a potential downstream target of the miR-192/-204-HOTTIP axis in HCC. Considering glutaminolysis as a crucial hallmark of cancer cells and significantly inhibited cell viability after silencingGLS1, we speculate that the miR-192/-204-HOTTIP axis may interrupt HCC glutaminolysis through GLS1 inhibition. These results elucidate that the miR-192/-204-HOTTIP axis might be an important molecular pathway during hepatic cell tumorigenesis. Our data in clinical HCC samples highlight miR-192, miR-204 and HOTTIP with prognostic and potentially therapeutic implications. Accumulated evidence demonstrated that long non-coding RNAs (lncRNAs) play a pivotal role in tumorigenesis. Here, we for the first time demonstrated how microRNAs (miRNAs) impact onco-lncRNA HOTTIP expression and its biological significance in hepatocellular carcinoma (HCC). We identified miR-192 and miR-204 as two miRNAs suppressing HOTTIP expression via the Argonaute 2-mediated RNA interference pathway. The dysregulation of the three ncRNAs was associated with overall survival of HCC patients. The posttranscriptional silencing of HOTTIP by miR-192, miR-204 or HOTTIP siRNAs could significantly suppress viability of HCC cells in vitro and in vivo. Besides one of the known target gene HOXA13, glutaminase was identified as a potential downstream target of the miR-192/-204-HOTTIP axis in HCC. Our data will have high impact on our understanding of how miRNAs are involved in the fine-regulation of lncRNAs and the potential translation in clinic.

The identification of two regulatory ESCC susceptibility genetic variants in the TERT-CLPTM1L loci The identification of two regulatory ESCC susceptibility genetic variants in the TERT-CLPTM1L loci

5S rRNA plays an important part in ribosome biology and is over‐expression in multiple cancers. In this study, we found that 5S rRNA is a direct target of miR‐150 and miR‐383 in esophageal squamous cell carcinoma (ESCC). Overexpression of miR‐150 and miR‐383 inhibited ESCC cell proliferation in vitro and in vivo. Moreover, 5S rRNA silencing by miR‐150 and miR‐383 might intensify rpL11–c‐Myc interaction, which attenuated role of c‐Myc as an oncogenic transcriptional factor and dysregulation of multiple c‐Myc target genes. Taken together, our results highlight the involvement of miRNAs in ribosomal regulation during tumorigenesis.

TreRNA is a long non‐coding RNA (lncRNA) involved in cancer progression. In this study, we show that miR‐190a can silence treRNA post‐transcriptionally. Suppression of treRNA by miR‐190a led to significant changes of mesenchymal–epithelial transition markers and impaired migration and invasion capability of hepatoma cells. TCGA data indicated that miR‐190a exhibited lower expression in hepatoma tissues, especially from patients with vascular tumor invasion, compared to normal tissues. Our results reveal the involvement of miR‐190a–treRNA axis in hepatoma progression and shed light on lncRNA‐based cancer therapies for hepatoma patients at high risk of metastasis.

As a well-known DNA repair gene, RAD52 plays an essential role in homologous recombination repair of double strand break, maintenance of genomic stability and prevention of cell malignant transformation. Previous genome-wide association studies (GWASs) have identified common genetic variants at 12p13.33 RAD52 locus associated with lung cancer risk in Caucasians. However, little or nothing has been known about the RAD52 single nucleotide polymorphisms (SNPs) in small cell lung cancer (SCLC) in the Chinese population. As a result, we examined the association between six RAD52 SNPs (rs10849605, rs1051669, rs10774474, rs11571378, rs7963551 and rs6489769) and SCLC susceptibility in Chinese. After 520 SCLC cases and 1040 controls in two independent case-control sets were genotyped, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression. We found that only the RAD52 rs7963551 SNP was significantly associated with SCLC risk among six RAD52 SNPs genotyped. The odds of having the rs7963551 CA genotype in SCLC patients was 0.38 (95% CI = 0.24-0.62, P = 1.1×10(-4)) compared with the CC genotype. Stratified analyses of association between rs7963551 SNP and SCLC risk indicated that the functional polymorphism was only significantly associated with decreased risk among smokers but not nonsmokers. Our results demonstrated that the functional RAD52 rs7963551 SNP contributes to susceptibility to developing SCLC in the Chinese population.

A functional rs4245739 A>C single nucleotide polymorphism (SNP) locating in the MDM43’-untranslated (3’-UTR) region creates a miR-191-5p or miR-887-3p targeting sites. This change results in decreased expression of oncogene MDM4. Therefore, we examined the association between this SNP and small cell lung cancer (SCLC) risk as well as its regulatory function in SCLC cells. Genotypes were determined in two independent case-control sets consisted of 520SCLC cases and 1040 controls from two regions of China. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression. The impact of the rs4245739 SNP on miR-191-5p/miR-887-3p mediated MDM4 expression regulation was investigated using luciferase reporter gene assays. We found that the MDM4 rs4245739AC and CC genotypes were significantly associated with decreased SCLC susceptibility compared with the AA genotype in both case-control sets (Shandong set: OR = 0.53, 95% CI = 0.32–0.89, P = 0.014; Jiangsu set: OR = 0.47, 95% CI = 0.26–0.879, P = 0.017). Stratified analyses indicated that there was a significantly multiplicative interaction between rs4245739 and smoking (P_interactioin = 0.048). After co-tranfection of miRNAs and different allelic-MDM4 reporter constructs into SCLC cells, we found that the both miR-191-5p and miR-887-3p can lead to significantly decreased MDM4 expression activities in the construct with C-allelic 3’-UTR but not A-allelic 3’-UTR, suggesting a consistent genotype-phenotype correlation. Our data illuminate that the MDM4rs4245739SNP contributes to SCLC risk and support the notion that gene 3’-UTR genetic variants, impacting miRNA-binding, might modify SCLC susceptibility.

B-cell lymphoma-2 (BCL-2) prevents apoptosis and its overexpression could promote cancer cell survival. Multiple functional BCL-2 genetic polymorphisms, such as rs2279115, rs1801018 and rs1564483, have been identified previously and might be involved in cancer development through deregulating BCL-2 expression. Therefore, we examined associations between these three polymorphisms and esophageal squamous cell carcinoma (ESCC) susceptibility as well as its biological function in vivo. Genotypes were determined in two independent case-control sets consisted of 1588 ESCC patients and 1600 controls from two regions of China. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression. The impact of the rs2279115 polymorphism on BCL-2 expression was detected using esophagus tissues. Our results demonstrated that the BCL-2 rs2279115 AA genotype was significantly associated with decreased ESCC risk compared with the CC genotype (OR = 0.72, 95% CI = 0.57–0.90, P = 0.005), especially in nonsmokers (OR = 0.42, 95% CI = 0.29–0.59, P = 0.001) or nondrinkers (OR = 0.44, 95% CI = 0.32–0.62, P = 0.002). Genotype-phenotype correlation studies demonstrated that subjects with the rs2279115 CA and AA genotypes had a statistically significant decrease of BCL-2 mRNA expression compared to the CC genotype in both normal and cancerous esophagus tissues. Our results indicate that the BCL-2 rs2279115 polymorphism contributes to ESCC susceptibility in Chinese populations.

Recent genome-wide association studies (GWAS) have identified eleven leukocyte telomere length (LTL)-related single nucleotide polymorphisms (SNPs). Since LTL has been associated with risk of many malignancies, LTL-related SNPs may contribute to cancer susceptibility. To test this hypothesis in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), we genotyped these eleven LTL-related SNPs in a case-control set including 1186 HBV-related HCC cases, 508 chronic HBV carriers and 1308 healthy controls at the discovery stage. The associations of HCC risk with these SNPs were further confirmed in an independent case-control set. We found that 1p34.2 rs621559 and 14q21 rs398652 were significantly associated with HBV-related HCC risk (both P<0.005 after Bonferroni corrections). There was no significant difference of either rs621559 or rs398652 genotypes between chronic HBV carriers and healthy controls, demonstrating that the association was not due to predisposition to HBV infection. In the pooled analyses (1806 HBV-related HCC cases and 1954 controls), we observed a decreased HCC risk, 0.72-times, associated with the 1p34.2 rs621559 AA genotype compared to the GG genotype (P = 1.6×10−6). Additionally, there was an increased HCC risk, 1.27-fold, associated with the rs398652 GG genotype (P = 3.3×10−6). A statistical joint effect between the rs621559 GG and rs398652 GG genotypes may exist in elevating risk of HBV-related HCC. We show, for the first time, that rs398652 and rs621559 might be marker genetic variants for risk of HBV-related HCC in the Chinese population.