Project description:MicroRNAs (miRNAs) are involved in cancer genesis and progression via acting as tumor suppressors or oncogenes. Previous studies report that miR-1296 shows upregulation in both colorectal cancer (CRC) tissues and plasma samples. However, the accurate clinical significance of miR-1296 and its role in CRC have not been well investigated. The aim of the present study was to disclose the aberrant expression, clinical significance, and the relevant biological function of miR-1296 in CRC. We found a marked upregulation of miR-1296 expression in CRC tissues compared to tumor-adjacent tissues. MiR-1296 overexpression was detected in five CRC cell lines (HCT116, Caco2, HT29, SW620 and SW480). High miR-1296 level was remarkably correlated with tumor size (>5cm), lymph node metastasis and TNM stage (III+IV). Notably. High miR-1296 expression was identified as a predictive factor for poor prognosis of CRC patients by survival analysis. MiR-1296 knockdown inhibited proliferation, migration, invasion capacities of HCT116 and SW480 cells in vitro. Moreover, miR-1296 silencing restrained the growth of CRC cells in vivo. Splicing factor proline and glutamine rich (SFPQ), a novel RNA binding protein, was identified as a direct target gene of miR-1296 in CRC. Downregulation of SFPQ expression was inversely associated with miR-1296 expression in CRC tissues. The Cancer Genome Atlas (TCGA) data revealed the prognostic value of dysregulated SFPQ in CRC patients. Interestingly, our findings established that the oncogenic role of miR-1296 was at least partially mediated by SFPQ in CRC cells. Collectively, these data indicate that miR-1296 accelerates CRC progression possibly by targeting SFPQ and may serve as a potential predictive factor and therapeutic target for CRC.
Project description:Long non‑coding RNAs (lncRNAs) are widely studied in cancer pathogenesis. Accumulating evidence has demonstrated that lncRNAs are involved in the cellular progression of colorectal cancer (CRC). However, the regulatory mechanism of lncRNA TMPO‑antisense (AS)1 in CRC has not been fully elucidated. The present study aimed to elucidate the role and regulatory mechanisms of lncRNA TMPO‑AS1 in CRC. In the present study, the expression levels of TMPO‑AS1 and microRNA‑143‑3p (miR‑143‑3p) were detected using reverse transcription‑quantitative PCR assay. The relative protein expression levels were measured via western blot analysis. MTT and Transwell assays were used to determine cell proliferation, migration and invasion, while a luciferase reporter assay was performed to assess the relationship between TMPO‑AS1 and miR‑143‑3p. In addition, a tumor animal model was used to investigate the effect of TMPO‑AS1 on tumor growth in CRC in vivo. TMPO‑AS1 expression was increased and miR‑143‑3p expression was decreased in CRC cells. TMPO‑AS1 knockdown and miR‑143‑3p overexpression significantly inhibited cell proliferation, migration and invasion of CRC cells. Luciferase reporter assay results demonstrated that miR‑143‑3p was a direct target of TMPO‑AS1. Inhibition of miR‑143‑3p could alleviate the suppressive effects of TMPO‑AS1 deletion on cell proliferation, migration and invasion of CRC cells. Furthermore, TMPO‑AS1 deletion could inhibit tumor growth in CRC in vivo. It was concluded that TMPO‑AS1 regulated cell proliferation, migration and invasion of CRC cells by targeting miR‑143‑3p. These findings provided a new regulatory network and therapeutic target for the treatment of CRC.
Project description:NUFIP1 is an RNA-binding protein that interacts with fragile X mental retardation protein (FMRP) in the messenger ribonucleoprotein particle (mRNP). We previously showed that NUFIP1 was upregulated in colorectal cancer (CRC), but how the protein may contribute to the disease and patient prognosis is unknown. Here we combine database analysis, microarray, quantitative PCR, and immunohistochemistry of patients' samples to confirm our previous findings on NUFIP1 overexpression in CRC, and to reveal that increased expression of NUFIP1 in CRC tissues correlated with worse overall, recurrence-free, event-free and disease-free survival in patients, as well as with more advanced CRC clinicopathological stage. Loss of function analysis demonstrated that NUFIP1 knockdown suppressed cell growth in vitro and in vivo, inhibited cell viability and survival, and induced cell cycle arrest and apoptosis in vitro, as well as up-regulated Bax and down-regulated Bcl-2 protein expression. In addition, as a natural anticancer triterpene from various fruits and vegetables, ursolic acid (UA) treatment suppressed cell proliferation, down-regulated NUFIP1 protein expression, and further enhanced the effects of NUFIP1 knockdown in CRC cells in vitro. NUFIP1 knockdown up-regulated the expression of 136 proteins, down-regulated the expression of 41 proteins, and enriched multiple signaling pathways including the senescence-associated heterochromatin foci (SAHF) pathway. Furthermore, NUFIP1 knockdown enhanced the expression of senescence-associated-β-galactosidase (SA-β-gal), the SAHF markers HP1γ and trimethylation (H3k9me3), and the senescence-related protein HMGA2, as well as both p53 and its downstream p21 protein expression. Our findings suggest that NUFIP1 is overexpressed in CRC and correlates with disease progression and poor patient survival. NUFIP1 may exert oncogenic effects partly by altering senescence. UA may show potential to treat CRC by down-regulating NUFIP1.
Project description:Butyrate is a short chain fatty acid present in a high concentration in the gut lumen. It has been well documented that butyrate, by serving as an energetic metabolite, promotes the proliferation of normal colonocytes while, by serving as a histone deacetylase inhibitor, epigenetically suppressing the proliferation of cancerous counterparts undergoing the Warburg effect. However, how butyrate interrupts the metabolism of colorectal cancer cells and ultimately leads to the suppression of cell proliferation remains unclear. Here, we employed a metabolomics-proteomics combined approach to explore the link between butyrate-mediated proliferation arrest and cell metabolism. A metabolomics study revealed a remodeled metabolic profile with pronounced accumulation of pyruvate, decreased glycolytic intermediates upstream of pyruvate and reduced levels of nucleotides in butyrate-treated HCT-116 cells. Supplementation of key metabolite intermediates directly affected cancer-cell metabolism and modulated the suppressive effect of butyrate in HCT-116 cells. By a Drug Affinity Responsive Target Stability (DARTS)-based quantitative proteomics approach, we revealed the M2 isoform of a pyruvate kinase, PKM2, as a direct binding target of butyrate. Butyrate activates PKM2 via promoting its dephosphorylation and tetramerization and thereby reprograms the metabolism of colorectal cancer cells, inhibiting the Warburg effect while favoring energetic metabolism. Our study thus provides a mechanistic link between PKM2-induced metabolic remodeling and the antitumorigenic function of butyrate and demonstrates a widely applicable approach to uncovering unknown protein targets for small molecules with biological functions.
Project description:Colorectal cancer (CRC) is now the third most prevalent tumor and one of the deadliest cancers worldwide, with an increasing prevalence every year. Therefore, we urgently need to understand the mechanisms regulating the progression of colorectal cancer and find potential diagnostic biomarkers. In this study, we performed an analysis using the TCGA and GEO databases to find a molecular biomarker for the diagnosis of CRC, namely CTPS1. The results of this analysis revealed that CTPS1 could promote tumor proliferation and metastasis. Furthermore, bioinformatics analysis revealed that CTPS1 promoted CRC progression through cell cycle and p53 pathways. Further investigation demonstrated that CTPS1 might be involved in the regulation of CCNB1, RRM2, GTSE1, CDK2 and CHEK2 genes. Moreover, PCR confirmed that CTPS1 regulated GTSE1 and CDK2 molecules. Then, western blot was used to verify that CTPS1 promoted the expression of GTSE1 and CDK2 by inhibiting the expression of p53. In summary, we identified an important diagnostic biomarker for CRC, namely CTPS1, and its importance was validated at the cellular level. These results suggest that CTPS1 could serve as a candidate biomarker for CRC and CTPS1 inhibitors may be a potential treatment for CRC.
Project description:Curcumin, the yellow pigment of turmeric found in Southeast Indian food, is one of the most popular phytochemicals for cancer prevention. Numerous reports have demonstrated modulation of multiple cellular signaling pathways by curcumin and its molecular targets in various cancer cell lines. To identify a new molecular target of curcumin, we used shape screening and reverse docking to screen the Protein Data Bank against curcumin. Cyclin-dependent kinase 2 (CDK2), a major cell-cycle protein, was identified as a potential molecular target of curcumin. Indeed, in vitro and ex vivo kinase assay data revealed a dramatic suppressive effect of curcumin on CDK2 kinase activity. Furthermore, curcumin induced G1 cell-cycle arrest, which is regulated by CDK2 in HCT116 cells. Although the expression levels of CDK2 and its regulatory subunit, cyclin E, were not changed, the phosphorylation of retinoblastoma (Rb), a well-known CDK2 substrate, was reduced by curcumin. Because curcumin induced cell-cycle arrest, we investigated the antiproliferative effect of curcumin on HCT116 colon cancer cells. In this experiment, curcumin suppressed HCT116 cell proliferation effectively. To determine whether CDK2 is a direct target of curcumin, CDK2 expression was knocked down in HCT116 cells. As expected, HCT116 sh-CDK2 cells exhibited G1 arrest and reduced proliferation. Because of the low levels of CDK2 in HCT116 sh-CDK2 cells, the effects of curcumin on G1 arrest and cell proliferation were not substantially relative to HCT116 sh-control cells. From these results, we identified CDK2 as a direct target of curcumin in colon cancer cells.
Project description:While it is known that miR-203 is frequently downregulated in many types of human cancer, little is known regarding its expression and functional role in colorectal cancer (CRC). In this study, we aimed to investigate the expression and the potential mechanisms of miR-203 in colorectal cancer. MiR-203 was significantly downregulated in CRC tissues compared with matched normal adjacent tissues. Our clinical data show that decreased miR-203 was associated with an advanced clinical tumor-node-metastasis stage, lymph node metastasis, and poor survival in CRC patients. Furthermore, externally induced expression of miR-203 significantly inhibited CRC cell proliferation and invasion in vitro and in vivo. Mechanistically, we identified EIF5A2 as a direct and functional target of miR-203. The levels of miR-203 were inversely correlated with levels of the EIF5A2 in the CRC tissues. Restoration of EIF5A2 in the miR-203-overexpressing CRC cells reversed the suppressive effects of miR-203. Our results demonstrate that miR-203 serves as a tumor suppressor gene and may be useful as a new potential therapeutic target in CRC.
Project description:Malignant gliomas are lethal cancers that display striking cellular heterogeneity. A highly tumorigenic glioma tumor subpopulation, termed cancer stem cells or tumor-initiating cells, promotes therapeutic resistance and tumor angiogenesis. Therefore, targeting cancer stem cells may improve patient survival. We interrogated the role of a neuronal cell adhesion molecule, L1CAM, in glioma stem cells as L1CAM regulates brain development and is expressed in gliomas. L1CAM(+) and CD133(+) cells cosegregated in gliomas, and levels of L1CAM were higher in CD133(+) glioma cells than normal neural progenitors. Targeting L1CAM using lentiviral-mediated short hairpin RNA (shRNA) interference in CD133(+) glioma cells potently disrupted neurosphere formation, induced apoptosis, and inhibited growth specifically in glioma stem cells. We identified a novel mechanism for L1CAM regulation of cell survival as L1CAM knockdown decreased expression of the basic helix-loop-helix transcription factor Olig2 and up-regulated the p21(WAF1/CIP1) tumor suppressor in CD133(+) glioma cells. To determine if targeting L1CAM was sufficient to reduce glioma stem cell tumor growth in vivo, we targeted L1CAM in glioma cells before injection into immunocompromised mice or directly in established tumors. In each glioma xenograft model, shRNA targeting of L1CAM expression in vivo suppressed tumor growth and increased the survival of tumor-bearing animals. Together, these data show that L1CAM is required for maintaining the growth and survival of CD133(+) glioma cells both in vitro and in vivo, and L1CAM may represent a cancer stem cell-specific therapeutic target for improving the treatment of malignant gliomas and other brain tumors.
Project description:In breast cancer cells, heterodimerization of HER2 and HER3 plays important and dominant roles in the functionality and transformation of HER-mediated pathways, in particular the PI3K/Akt survival pathway. HER3 was considered as a major signaling hub in HER2-amplified cancers. Inhibition of HER3 expression may therefore represent a rational therapeutic approach to breast cancers where HER2/HER3-mediated signaling plays a role in tumorigenesis and progression. miRNAs exerts important roles in regulating gene expressions by binding to and repressing target mRNAs. Here we reported that miRNA-450b-3p inhibits HER3 expression by directly targeting 3' UTR of HER3 mRNA and represses the downstream signal transductions of HER family. Overexpression of miRNA-450b-3p in SKBR3 cells inhibits cells clonogenic potential and enhances their sensitivity to trastuzumab, a monoclonal antibody that binds to the HER2 receptor, or doxorubicin through repressing proliferative signal pathways mediated by HER3/HER2/PI3K/AKT. Furthermore, we found that breast cancer patients with tumors that demonstrating upregulated HER3 (> 2-fold) and downregulated miR-450b-3p (> 2-fold) expressions compared with the paired adjacent non-tumorous tissues showed significantly poorer overall survival (P<0.05). Our study identified miRNA-450b-3p as a new tumor repressor and also provided some evidences suggesting that downregulation of miR-450b-3p expression with concurrent overexpression of HER3 may serve as a prognostic biomarker for poor overall survival in breast cancer patients.
Project description:PurposeRetinal pigment epithelium (RPE) cell proliferation is precisely regulated to maintain retinal homoeostasis. Microphthalmia-associated transcription factor (MITF), a critical transcription factor in RPE cells, has two alternatively spliced isoforms: (+)MITF and (-)MITF. Previous work has shown that (-)MITF but not (+)MITF inhibits RPE cell proliferation. This study aims to investigate the role of long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in regulating MITF splicing and hence proliferation of RPE cells.MethodsMouse RPE, primary cultured mouse RPE cells, and different proliferative human embryonic stem cell (hESC)-RPE cells were used to evaluate the expression of (+)MITF, (-)MITF, and NEAT1 by reverse-transcription PCR (RT-PCR) or quantitative RT-PCR. NEAT1 was knocked down using specific small interfering RNAs (siRNAs). Splicing factor proline- and glutamine-rich (SFPQ) was overexpressed with the use of lentivirus infection. Cell proliferation was analyzed by cell number counting and Ki67 immunostaining. RNA immunoprecipitation (RIP) was used to analyze the co-binding between the SFPQ and MITF or NEAT1.ResultsNEAT1 was highly expressed in proliferative RPE cells, which had low expression of (-)MITF. Knockdown of NEAT1 in RPE cells switched the MITF splicing pattern to produce higher levels of (-)MITF and inhibited cell proliferation. Mechanistically, NEAT1 recruited SFPQ to bind directly with MITF mRNA to regulate its alternative splicing. Overexpression of SFPQ in ARPE-19 cells enhanced the binding enrichment of SFPQ to MITF and increased the splicing efficiency of (+)MITF. The binding affinity between SFPQ and MITF was decreased after NEAT1 knockdown.ConclusionsNEAT1 acts as a scaffold to recruit SFPQ to MITF mRNA and promote its binding affinity, which plays an important role in regulating the alternative splicing of MITF and RPE cell proliferation.