RNA binding protein PUM2 promotes hepatocellular carcinoma proliferation and apoptosis via binding to the 3'UTR of BTG3.

Pumilio homolog 2 (PUM2) is an RNA-binding protein that functions as an oncogene in various types of cancer. However, its role in hepatocellular carcinoma (HCC) has remained to be fully elucidated. In the present study, the role of PUM2 was investigated in HCC and its regulation was assessed by examining its binding to the 3'-untranslated region (UTR) of B-cell translocation gene 3 (BTG3). The expression levels of PUM2 were determined in datasets from the UALCAN and Cancer Cell Line Encyclopedia databases. Furthermore, Gene Expression Profiling Interactive Analysis was used to analyze overall survival in patients with HCC. Reverse transcription-quantitative PCR (RT-qPCR) and western blot analyses were then performed to detect the expression levels of PUM2 and BTG3 in HCC cells. Cell proliferation was assessed using Cell Counting Kit-8 and colony-formation assays. The induction of cell apoptosis was evaluated using TUNEL and western blotting assays. StarBase and RNA-Protein Interaction Prediction were used to determine the possible direct interaction between PUM2 and BTG3. The interaction between PUM2 and BTG3 was then verified by luciferase reporter and RNA-binding protein immunoprecipitation assays. The results indicated that PUM2 expression was upregulated in HCC tissues and cells and that it was associated with the prognosis of patients with HCC. PUM2 silencing inhibited the proliferation and promoted the apoptosis of Huh-7 cells. In addition, PUM2 was confirmed to directly bind to the 3'UTR of BTG3. Downregulation of BTG3 reversed the effects of PUM2 silencing on cell proliferation and apoptosis in Huh-7 cells. Collectively, the results suggested that PUM2 regulated HCC cell proliferation and apoptosis via interacting with BTG3, which may provide a novel therapeutic strategy for the treatment of human HCC.

Hydroxysafflor yellow A inhibits the proliferation, migration, and invasion of colorectal cancer cells through the PPARγ/PTEN/Akt signaling pathway.

The natural compound Hydroxysafflor yellow A (HSYA) has been demonstrated to exert anti-cancer effect on multiple cancers. This study aimed to clarify the role of HSYA in inhibiting colorectal cancer (CRC) in vitro and the underlying mechanisms. Different concentrations of HSYA (0, 25, 50, and 100 µM) was exposed to HCT116 CRC cells, then cell proliferation, apoptosis, migration, and invasion were estimated by colony formation assay, TUNEL staining, wound-healing, and transwell assays, respectively. Western blotting assay was utilized to observe the expression of proteins involved in cell apoptosis, migration, and peroxisome proliferator-activated receptor γ (PPARγ)/PTEN/Akt signaling, including PCNA, Bax, Bcl-2, cleaved-caspase3, E-cadherin, N-cadherin, vimentin, PPARγ, and phosphorylated (p)-Akt. HCT116 cells that treated with 100 µM HSYA were also pre-treated with PPARγ antagonist, GW9662, or knockdown with PPARγ using short hairpin (sh)-RNA, to down-regulate PPARγ expression. Then, the above functional analysis was repeated. Results demonstrated that HSYA (25, 50 and 100 µM) significantly reduced HCT116 cell viability, but had no effect on the cell viability of human normal intestinal epithelial cell HIEC. HSYA also inhibited colony formation, migration, and invasion but promoted apoptosis of HCT116 cell in a concentration-dependent manner. Besides, the PPARγ/PTEN/Akt signaling was activated upon HSYA treatment. Finally, GW9662 and PPARγ knockdown blocked all the effects of HSYA on HCT116 cells. In conclusion, HSYA could exhibit anti-cancer effect on CRC via activating PPARγ/PTEN/Akt signaling, thereby inhibiting cells proliferation, migration, and invasion in vitro.

miR-107 regulates tumor progression by targeting NF1 in gastric cancer.

Our previous genome-wide miRNA microarray study revealed that miR-107 was upregulated in gastric cancer (GC). In this study we aimed to explore its biological role in the pathogenesis of GC. Integrating in silico prediction algorithms with western blotting assays revealed that miR-107 inhibition enhanced NF1 (neurofibromin 1) mRNA and protein levels, suggesting that NF1 is one of miR-107 targets in GC. Luciferase reporter assay revealed that miR-107 suppressed NF1 expression by binding to the first potential binding site within the 3'-UTR of NF1 mRNA. mRNA stable assay indicated this binding could result in NF1 mRNA instability, which might contribute to its abnormal protein expression. Functional analyses such as cell growth, transwell migration and invasion assays were used to investigate the role of interaction between miR-107 and its target on GC development and progression. Moreover, We investigated the association between the clinical phenotype and the status of miR-107 expression in 55 GC tissues, and found the high expression contributed to the tumor size and depth of invasion. The results exhibited that down regulation of miR-107 opposed cell growth, migration, and invasion, whereas NF1 repression promoted these phenotypes. Our findings provide a mechanism by which miR-107 regulates NF1 in GC, as well as highlight the importance of interaction between miR-107 and NF1 in GC development and progression.

The prognostic significance of HOTAIR for predicting clinical outcome in patients with digestive system tumors.

PURPOSE: Although some studies have assessed the prognostic value of HOTAIR in patients with digestive system tumors, the relationship between the HOTAIR and outcome of digestive system tumors remains unknown. METHODS: The PubMed was searched to identify the eligible studies. Here, we performed a meta-analysis with 11 studies, including a total of 903 cases. Pooled hazard ratios (HRs) and 95 % confidence interval (CI) of HOTAIR for cancer survival were calculated. RESULTS: We found that the pooled HR elevated HOTAIR expression in tumor tissues was 2.36 (95 % CI 1.88-2.97) compared with patients with low HOTAIR expression. Moreover, subgroup analysis revealed that HOTAIR overexpression was also markedly associated with short survival for esophageal squamous cell carcinoma (HR 2.19, 95 % CI 1.62-2.94) and gastric cancer (HR 1.66, 95 % CI 1.02-2.68). In addition, up-regulated HOTAIR was significantly related to survival of digestive system cancer among the studies with more follow-up time (follow time ≥ 5 years) (HR 2.51, 95 % CI 1.99-3.17). When stratified by HR resource and number of patients, the result indicated consistent results with the overall analysis. Subgroup analysis on ethnicities did not change the prognostic influence of elevated HOTAIR expression. Additionally, we conducted an independent validation cohort including 71 gastric cancer cases, in which patients with up-regulated HOTAIR expression had an unfavorable outcome with HR of 2.10 (95 % CI 1.10-4.03). CONCLUSION: The results suggest that aberrant HOTAIR expression may serve as a candidate positive marker to predict the prognosis of patients with carcinoma of digestive system.

Genetic variant in 8q24 is associated with prognosis for gastric cancer in a Chinese population.

BACKGROUND AND AIM: Single nucleotide polymorphisms (SNPs) located in long noncoding RNA CASC8 gene may influence the process of splicing and stability of messenger RNA conformation, resulting in the modification of its interacting partners. Genome-wide association studies have identified the SNP rs10505477 and SNP rs1562430 in CASC8 were associated with risk of the colorectal cancer (CRC) and breast cancer, respectively. METHODS: In the present study, we genotyped the 940 surgically resected gastric cancer patients to explore the association between these two SNPs (e.g., rs10505477 and rs1562430) and survival of gastric cancer in a Chinese population. RESULTS: We found that the patients carrying rs10505477 GG genotype survived for a longer time than those with the GA and AA genotypes (log-rank P = 0.030). The similar result was also found in the dominant model (GA/AA vs GG, HR = 1.32, 95% CI = 1.08-1.63, log-rank P = 0.008). This risk effect was more pronounced among patients with tumor size ≤ 5 cm, diffuse-type gastric cancer, lymph node metastasis, no distant metastasis, and TNM stage III and IV. Furthermore, the area under the curve at five years was dramatically increased from 0.619 to 0.624 after adding the rs10505477 risk score to the traditional clinical risk score (TNM stage and lymph node metastasis). However, there was no association be found between the rs1562430 and the survival of gastric cancer. CONCLUSION: These findings suggested the SNP rs10505477 may contribute to the survival of gastric cancer and be a potential prognostic biomarker of gastric cancer.

A common genetic variation in the promoter of miR-107 is associated with gastric adenocarcinoma susceptibility and survival.

BACKGROUND: Global miRNA expression profile has been widely used to characterize human cancers. It is well established that genetic variants in miRNAs can modulate miRNA biogenesis and disease risk. METHODS: Genome-wide miRNA microarray was employed for assessment of miRNA expression profile of gastric adenocarcinoma (GAC). The variants of significantly dysregulated miRNA were genotyped in test (715 cases and 804 controls) and validation (940 cases and 1050 controls) subject sets. RESULTS: MiRNA microarray revealed that 12 miRNAs including miR-107 significantly dysregulated in GAC tissues. The sequencing of the promoter of miR-107 identified 3 SNPs (rs11185777, rs78591545, and rs2296616) with minor allele frequency (MAF)>5%. Analyzing their association with GAC risk and prognosis revealed that the C allele of rs2296616 (T>C) was significantly associated with the decreased risk of GAC among the test, validation and combined sets (TC/CC vs. TT, adjusted OR=0.39, 95% CI=0.31-0.49 for the combined set). However, the C allele was related to an unfavorable prognosis of Cardia GAC (CGAC) (adjusted HR=1.49, 95% CI=1.01-2.20). In vivo evidence showed that the individuals with the rs2296616C allele had lower miR-107 expression compared with the homozygous T allele carriers. CONCLUSION: miR-107 is dysregulated in GAC pathogenesis and the SNP rs2296616 may play a role in the process.

Hsa-miR-181a-5p expression and effects on cell proliferation in gastric cancer.

PURPOSE: MicroRNAs (miRNAs) are small endogenous, non-coding, single-stranded RNAs (approximately 22 nt). Accumulating evidence has shown that aberrant miRNA expression is pronounced and correlated with gastric cancer genesis and progression. MATERIALS AND METHODS: Expression levels of miR-181a-5p in GC tissues and cell lines were assessed by qRT-PCR and tested for correlation with clinical features. In addition, effects of miR-181a-5p on GC cell growth were investigated. RESULTS: Our findings indicate that miR-181a-5p is upregulated in GC, in correlation with lymph node invasion, nerve invasion and vascular invasion (P<0.05). Enforced expression of miR-181a -5p promoted cell proliferation ability. CONCLUSIONS: This study suggested that increased miR-181a-5p is related to GC progression. MiR-181a-5p may represent a potential therapeutic target for GC.