Yujia Shan

MiR-106b and miR-93 regulate cell progression by suppression of PTEN via PI3K/Akt pathway in breast cancer

Accumulating evidences have revealed that dysregulated microRNAs (miRNAs) involve in the tumorigenesis, progression and even lead to poor prognosis of various carcinomas, including breast cancer. MiRNA-106b-5p (miR-106b) and miRNA-93-5p (miR-93) levels were confirmed to be significantly upregulated in breast cancer clinical samples (n=36) and metastatic cell line (MDA-MB-231) compared with those in the paired adjacent tissues and normal breast epithelial cell line (MCF-10A). Moreover, further research stated that the capability of migration, invasion and proliferation changed along with the altered expression of miR-106b and miR-93 in breast cancer. PTEN, the tumor-suppressor gene, was discovered to be reduced in breast cancer tissues or MDA-MB-231 cells with high levels of miR-106b and miR-93, which were inversely expressed in PTEN overexpression tissues or cells. Based on the investigation, miR-106b and miR-93 induced the migration, invasion and proliferation and simultaneously enhanced the activity of phosphatidylinositol-3 kinase (PI3K)/Akt pathway of MCF-7 cells, which could be blocked by upregulation of PTEN. Furthermore, suppression of PTEN reversed the function induced by anti-miR-106b and anti-miR-93 in MDA-MB-231 cells, indicating that PTEN was directly targeted by these miRNAs and acted as the potential therapeutic target for breast cancer therapy. In short, reductive PTEN mediated by miR-106b and miR-93 promoted cell progression through PI3K/Akt pathway in breast cancer.

Tumor-suppressive miR-26a and miR-26b inhibit cell aggressiveness by regulating FUT4 in colorectal cancer

Metastasis is a multistep molecular network process, which is the major cause of death in patients with colorectal cancer (CRC). MicroRNAs (miRNAs) play pivotal roles in tumorigenesis as either tumor suppressors or oncogenes. Increased expression of fucosyltransferase4 (FUT4) has been reported to be associated with the invasive and metastatic properties of CRC. Here to identify potential key miRNAs and their target genes for colorectal cancer (CRC), we compared miRNA expression profiles between metastatic CRC cell SW620 and primary CRC cell SW480. Microarray analysis revealed that there were 85 differentially expressed miRNAs in SW620 cells with highly metastatic potential compared to SW480 cells with lowly metastatic potential. The expression of miR-26a and miR-26b were lower in SW620 cells than in SW480 cells, as well as downregulated in tumor tissues than in adjacent normal tissues of CRC patients. By applying bioinformatic approaches for the prediction of miRNA targeting 3′-UTR of FUT4, we identified FUT4 as one of the miR-26a/26b-targeted genes, while the expression of the target gene exhibited patterns opposite to that of miR-26a/26b in CRC cell lines, tumor tissues and corresponding adjacent tissues. Forced miR-26a/26b expression affected migratory behavior of CRC cells and FUT4 expression, while altered expression of FUT4 in CRC cell lines modulated progression upon transfection with miR-26a/26b mimic or inhibiter. FUT4 also regulated directly aggressiveness of SW620 and SW480 cells. Moreover, statistical analyses revealed that low miR-26a/26b levels and high expression of FUT4 were positively correlated with poor overall survival. The identified CRC-restricted miR-26a and miR-26b might be implicated in cancer progression via their target gene FUT4, suggesting their potential usage in CRC treatment.

Downregulation of miR-224 and let-7i contribute to cell survival and chemoresistance in chronic myeloid leukemia cells by regulating ST3GAL IV expression

Acquired resistance to imatinib is frequently associated with poor clinical outcome of chronic myeloid leukemia (CML) patient. To date, evidence indicates that protein glycosylation and its upstream regulators might be implicated in tumorigenesis and chemoresistance occurrence. In current study we initially explored N-glycan profiles on the surface of CML cell lines and bone marrow mononuclear cells (BMMC) of CML patients by using mass spectrometry (MS) analysis. An elevated sialylation was detected in K562R cells (CML cells with imatinib resistance phenotype) compare to K562 cells. By quantitative real time-PCR (qRT-PCR) and western blotting analysis we observed that imatinib resistant K562R cells exhibited marked high levels of CMP-N-acetylneuraminate-beta-galactosamide-alpha-2,3-sialyltransferase (ST3Gal IV) as compared to imatinib sensitive K562 cells. Further studies revealed that manipulated expression of ST3GAL IV led to the significant alterations of cell cycle distribution, apoptotic signal, cell proliferation and the effectiveness of imatinib treatment. Using microRNA array, miRNA database searching and luciferase reporter assay, we identified that miR-224 and let-7i directly regulate the expression of ST3GAL IV gene. Moreover, engineered expression of miR-224 and let-7i in K562 and K562R cells could significantly affect ST6Gal IV-induced proliferation rate and drug-resistance. Thus we propose that miR-224 and let-7i regulate the proliferation and chemosensitivity of CML cells probably via targeting ST3GAL IV.

Upregulation of microRNA-135b and microRNA-182 promotes chemoresistance of colorectal cancer by targeting ST6GALNAC2 via PI3K/AKT pathway.

MicroRNAs (miRNAs) are increasingly involved in the development of drug resistance, including 5‐fluorouracil (5‐FU) resistance in colorectal cancer (CRC). Aberrant sialylation is correlated with human CRC. The study was to explore whether miR‐135b and miR‐182 modulated 5‐FU chemoresistance of CRC by targeting ST6GALNAC2 via PI3K/AKT pathway. MiR‐135b and miR‐182 were found to be up‐regulated in CRC tissues and 5‐FU resistant CRC cell lines. Forced miR‐135b and miR‐182 expression also affected ST6GALNAC2 levels. Using reporter‐gene assay, ST6GALNAC2 was identified as direct target of miR‐135b and miR‐182, while ST6GALNAC2 expression exhibited patterns opposite to that of miR‐135b and miR‐182 in CRC samples and cell lines. Interestingly, up‐regulation of miR‐135b or miR‐182 increased drug resistance and proliferation, but decreased apoptosis in 5‐FU resistant CRC cell lines. Suppression of these miRNAs implicated an inverse function, while altered expression of ST6GALNAC2 mediated CRC progression upon transfection with miR‐135b/‐182 mimic or inhibitor. Furthermore, miR‐135b and miR‐182 were clarified to regulate the activity of phosphoinositide‐3 kinase (PI3K)/AKT pathway. Inhibition of the PI3K/AKT pathway enhanced the chemosensitivity to 5‐FU in HCT‐8/5‐FU and LoVo/5‐FU. Taken together, miR‐135b and miR‐182 may reverse the resistance to 5‐FU in CRC cells by targeting ST6GALNAC2 via PI3K/AKT pathway, which render potential chemotherapy targets for the treatment of CRC.

miR-140-5p/miR-149 Affects Chondrocyte Proliferation, Apoptosis, and Autophagy by Targeting FUT1 in Osteoarthritis

Osteoarthritis (OA), the most prevalent chronic and degenerative joint disease, is characterized by articular cartilage degradation and chondrocyte injury. Increased cell apoptosis and defective cell autophagy in chondrocytes are a feature of degenerative cartilage. MicroRNAs (miRNAs) have been identified as potential regulators of OA. This study aimed to determine the potential role of miR-140-5p and miR-149 in apoptosis, autophagy, and proliferation in human primary chondrocytes and investigate the underlying mechanism. We revealed the differential expressional profiles of miR-140-5p/149 and fucosyltransferase 1 (FUT1) in the articular cartilage tissues of OA patients and normal people and validated FUT1 was a direct target of miR-140-5p/149. The overexpression of miR-140-5p/149 inhibited apoptosis and promoted proliferation and autophagy of human primary chondrocytes via downregulating FUT1. On the contrary, the downregulation of miR-140-5p/149 inhibited chondrocyte proliferation and autophagy, whereas the effect was reversed by FUT1 knockdown. Taken together, our data suggested that miR-140-5p and miR-149 could mediate the development of OA, which was regulated by FUT1. miR-140-5p/miR-149/FUT1 axis might serve as a predictive biomarker and a potential therapeutic target in OA treatment.

miR-182 and miR-135b Mediate the Tumorigenesis and Invasiveness of Colorectal Cancer Cells via Targeting ST6GALNAC2 and PI3K/AKT Pathway

BackgroundMetastasis is a leading cause of cancer-related death including colorectal cancer (CRC). MicroRNAs are known to regulate cancer pathways and to be expressed aberrantly in cancer. Aberrant sialylation is closely associated with malignant phenotype of tumor cells, including invasiveness and metastasis.AimThis study aimed to investigate the association of miR-182 and miR-135b with proliferation and invasion by targeting sialyltransferase ST6GALNAC2 in CRC cells and explore the potential molecular mechanism.MethodsWe measured the levels of miR-182, miR-135b, and ST6GALNAC2 in a series of CRC cell lines and tissues using real-time PCR. Bioinformatics analysis and luciferase reporter assay were performed to test the direct binding of miR-182 and miR-135b to the target gene ST6GALNAC2. We also analyzed the possible role of miR-182/-135b on colony formation, wound healing, invasion, and tube formation.ResultsThe expression of miR-182 and miR-135b was higher in tumor tissues compared to adjacent noncancerous tissues of CRC patients, as well as up-regulated in SW620 cells than in SW480 cells with different metastatic potential. By applying bioinformatics analysis and luciferase reporter assay, we identified ST6GALNAC2 as the direct target of miR-182/-135b. Furthermore, miR-182/-135b inhibited significantly ST6GALNAC2 expression, and consistently, ST6GALNAC2 mediated migration, adhesion, invasion, proliferation, and tumor angiogenesis in CRC cell lines. Additionally, PI3K/AKT signaling pathway was regulated by miR-182/135b, which was partially blocked by altered level of ST6GALNAC2 in CRC.ConclusionsThe miR-182/-135b/ST6GALNAC2/PI3K/AKT axis may serve as a predictive biomarker and a potential therapeutic target in CRC treatment.

Long non-coding RNA-SNHG7 acts as a target of miR-34a to increase GALNT7 level and regulate PI3K/Akt/mTOR pathway in colorectal cancer progression

BackgroundColorectal cancer (CRC) arises in a multistep molecular network process, which is from either discrete genetic perturbation or epigenetic dysregulation. The long non-coding RNAs (lncRNAs), emerging as key molecules in human malignancy, has become one of the hot topics in RNA biology. Aberrant O-glycosylation is a well-described hallmark of many cancers. GALNT7 acts as a glycosyltransferase in protein O-glycosylation, involving in the occurrence and development of CRC.MethodsThe microarrays were used to survey the lncRNA and mRNA expression profiles of primary CRC cell line SW480 and metastatic CRC cell line SW620. Cell proliferation, migration, invasion, and apoptosis were assayed. Xenograft mouse models were used to determine the role of lncRNA-SNHG7 in CRC in vivo. In addition, CNC analysis and competing endogenous analysis were used to detect differential SNHG7 and relational miRNAs expression in CRC cell lines.ResultsSNHG7 expression showed a high fold (SW620/SW480) in CRC microarrays. The CRC patients with high expression of SNHG7 had a significantly poor prognosis. Furthermore, SNHG7 promoted CRC cell proliferation, metastasis, mediated cell cycle, and inhibited apoptosis. SNHG7 and GALNT7 were observed for co-expression by CNC analysis, and a negative correlation of SNHG7 and miR-34a were found by competing endogenous RNA (ceRNA) analysis. Further results indicated that SNHG7 facilitated the proliferation and metastasis as a competing endogenous RNA to regulate GALNT7 expression by sponging miR-34a in CRC cell lines. SNHG7 also played the oncogenic role in regulating PI3K/Akt/mTOR pathway by competing endogenous miR-34a and GALNT7.ConclusionThe CRC-related SNHG7 and miR-34a might be implicated in CRC progression via GALNT7, suggesting the potential usage of SNHG7/miR-34a/GALNT7 axis in CRC treatment.

Functional screen analysis reveals miR-3142 as central regulator in chemoresistance and proliferation through activation of the PTEN-AKT pathway in CML

Chronic myeloid leukemia (CML) is caused by the constitutively active BCR-ABL tyrosine kinase. Although great progress has been made for improvement in clinical treatment during the past decades, it is common for patients to develop chemotherapy resistance. Therefore, further exploring novel therapeutic strategies are still crucial for improving disease outcome. MicroRNAs (miRNAs) represent a novel class of genes that function as negative regulators of gene expression. Recently, miRNAs have been implicated in several cancers. Previously, we identified 41 miRNAs that were dysregulated in resistant compared with adriamycin (ADR)-sensitive parental cells in CML. In the present study, we reported that miR-3142 are overexpressed in ADR-resistant K562/ADR cells and CML/multiple drug resistance patients, as compared with K562 cells and CML patients. Upregulation of miR-3142 in K562 cells accelerated colony formation ability and enhanced resisitance to ADR in vitro. Conversely, inhibition of miR-3142 expression in K562/ADR cells decreased colony-formation ability and enhanced sensitivity to ADR in vitro and in vivo. Significantly, our results showed miR-3142-induced ADR resistance through targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN), which led to downregulation of PTEN protein and activation of PI3 kinase (PI3K)/Akt pathway. Inhibition of Akt using Akt inhibitor or introduction of PTEN largely abrogated miR-3142-induced resistance. These findings indicated that miR-3142 induces cell proliferation and ADR resistance primarily through targeting the PTEN/PI3K/Akt pathway and implicate the potential application of miR-3142 in cancer therapy.

Long noncoding RNA HOTAIR promotes renal cell carcinoma malignancy through alpha-2, 8-sialyltransferase 4 by sponging microRNA-124

Accumulating evidence demonstrated that the long noncoding RNA (lncRNA) HOTAIR (Hox transcript antisense intergenic RNA) plays key role in renal cell carcinoma (RCC) malignancy, while microRNA‐124 (miR‐124) is a tumour suppressor in RCC. The aim of this work was to assess the biological function of HOTAIR and to explore underlying mechanism involved in HOTAIR/miR‐124/alpha‐2, 8‐sialyltransferase 4 (ST8SIA4) axis‐regulated progression in RCC.

Long non-coding RNA HOTAIR promotes osteoarthritis progression via miR-17-5p/FUT2/β-catenin axis

Osteoarthritis (OA) is a chronic joint disease and hard to cure at present. Accumulating evidence suggests long noncoding RNA-HOTAIR (lncRNA-HOTAIR) plays important role in OA progression. However, the underlying molecular mechanism of HOTAIR in OA progression has not been well elucidated. In the present study, we identified that HOTAIR level was upregulated in OA cartilage tissues. High expression of HOTAIR was correlated with modified Mankin scale, extracellular matrix (ECM) degradation and chondrocytes apoptosis. The expression of miR-17-5p was down-regulated, while alpha-1, 2 fucosyltransferase 2 (FUT2) was increased in OA progression. Luciferase reporter and RNA immunoprecipitation (RIP) assays indicated that HOTAIR could directly bind to miR-17-5p and indirectly upregulate FUT2 level. Functional investigation revealed HOTAIR and FUT2 aggravated ECM degradation and chondrocytes apoptosis, and this effect could be reversed by miR-17-5p. Altered FUT2 modulated the activity of wnt/β-catenin pathway and HOTAIR/miR-17-5p also mediated wnt/β-catenin pathway through FUT2. Collectively, our findings indicated that HOTAIR/miR-17-5p/FUT2 axis contributed to OA progression via wnt/β-catenin pathway, which might provide novel insights into the function of lncRNA-driven in OA.