Jiateng Zhong

The expression and clinical significance of microRNAs in colorectal cancer detecting

MicroRNAs (miRNAs) are small non-coding RNAs which regulate gene expressions post-transcriptionally. Nowadays, various miRNAs have been found to be sensitive and specific biomarkers for the early diagnosis of colorectal cancer (CRC); however, there are different, even conflicting results in different publications concerning the diagnostic accuracy of miRNA. Therefore, we aim to conduct a meta-analysis of the relevant publications to comprehensively evaluate the diagnostic value of miRNAs in CRC detection. Several public databases such as PubMed, Embase, and Google Scholar were retrieved up to July 13, 2014. Sensitivity was applied to plot the summary receiver operator characteristic (SROC) curve against specificity. The area under the SROC curve (AUC) was calculated to assess the classified effects. STATA 12.0 software was used to perform all statistic analyses. A total of 29 articles, including 80 studies, were involved in our meta-analysis, 55 of which focus on single-miRNA assays and the other 25 on multiple-miRNA assays. Our results suggested that multiple-miRNA assays show a better diagnostic accuracy compared with single-miRNA assays. In addition, blood-based miRNA assays were more accurate than feces-based miRNA assays in CRC diagnosis. Our results also showed that miRNA diagnosis appear to be more accurate in Asians than in Caucasians. However, further researches are needed to validate our results and the feasibility of miRNAs as biomarkers in routine clinical diagnosis of CRC.

miR-96 promotes the growth of prostate carcinoma cells by suppressing MTSS1.

Prostate carcinoma (PC) is one of the most common cancers for males. However, the molecular mechanisms of PC progression are still to be uncovered. MicroRNA (miRNA) has been shown to be associated with the initiation and progression of prostate cancer. Among the identified tumor-promoting miRNAs, miR-96 has been well established to contribute to PC by reducing FOXO1 expression. This study is aimed to study if miR-96 can promote the progression of PC through other pathways. Our data reinforced the finding that the level of miR-96 was higher in PC samples and cell lines than in non-cancerous tissues and normal prostate epithelial cells. In addition, serum miR-96 abundance was also found to be elevated in PC patients. Decreasing miR-96 expression was able to suppress the proliferation, clonogenicity, and invasion of PC cells. Overexpressing miR-96 led to increased proliferation and colony formation of normal prostate epithelial cells. miR-96 level was found to be inversely associated with the abundance of metastasis suppressor protein 1 (MTSS1) messenger RNA (mRNA), which has been proved to be a tumor suppressor for PC. Predictive analysis indicated that there was a potential miRNA response elements (MREs) located within 3′UTR of MTSS1 mRNA. The changes in miR-96 expression can affect the levels of MTSS1 both at mRNA and protein levels. miR-96 also suppressed the activity of luciferase reporter under the regulation of 3′UTR of MTSS1. Further studies showed that MTSS1 restoration accounted for the effect of miR-96 reduction on PC cells. The overexpression of a recombinant MTSS1 resistant against miRNA regulation was also demonstrated to abolish the transforming effect of miR-96 on prostate epithelial cells. Taken together, we found that miR-96 has a higher abundance in serum samples of PC patients than healthy controls, implying that it may be used as a prognostic marker. MTSS1 is a new authentic target of miR-96 in PC. The above findings suggested that targeting miR-96 may be a promising strategy for PC treatment.

Effects of endoplasmic reticulum stress on the autophagy, apoptosis, and chemotherapy resistance of human breast cancer cells by regulating the PI3K/AKT/mTOR signaling pathway

Nowadays, although chemotherapy is an established therapy for breast cancer, the molecular mechanisms of chemotherapy resistance in breast cancer remain poorly understood. This study aims to explore the effects of endoplasmic reticulum stress on autophagy, apoptosis, and chemotherapy resistance in human breast cancer cells by regulating PI3K/AKT/mTOR signaling pathway. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to detect the cell viability of six human breast cancer cell lines (MCF-7, ZR-75-30, T47D, MDA-MB-435s, MDA-MB-453, and MDA-MB-231) treated with tunicamycin (5 µM), after which MCF-7 cells were selected for further experiment. Then, MCF-7 cells were divided into the control (without any treatment), tunicamycin (8 µ), BEZ235 (5 µ), and tunicamycin + BEZ235 groups. Cell viability of each group was testified by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Western blotting was applied to determine the expressions of endoplasmic reticulum stress and PI3K/AKT/mTOR pathway–related proteins and autophagy- and apoptosis-related proteins. Monodansylcadaverine and Annexin V–fluorescein isothiocyanate/propidium iodide staining were used for determination of cell autophagy and apoptosis. Furthermore, MCF-7 cells were divided into the control (without any treatment), tunicamycin (5 µM), cisplatin (16 µM), cisplatin (16 µM) + BEZ235 (5 µM), tunicamycin (5 µM) + cisplatin (16 µM), and tunicamycin (5 µM) + cisplatin (16 µM) + BEZ235 groups. Cell viability and apoptosis were also evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Annexin V–fluorescein isothiocyanate/propidium iodide staining. In MCF-7 cells treated with tunicamycin, cell viability decreased significantly, but PEAK, eIF2, and CHOP were upregulated markedly and p-PI3K, p-AKT, and p-MTOR were downregulated in dose- and time-dependent manners. In the tunicamycin + BEZ235 group, the cell viability was lower and the apoptosis rate was higher than those of the control and monotherapy groups. Compared with the cisplatin group, the tunicamycin + cisplatin group showed a relatively higher growth inhibition rate; the growth inhibition rate substantially increased in the tunicamycin + cisplatin + BEZ235 group than the tunicamycin + cisplatin group. The apoptosis rate was highest in tunicamycin + cisplatin + BEZ235 group, followed by tunicamycin + cisplatin group and then cisplatin group. Our study provide evidence that endoplasmic reticulum stress activated by tunicamycin could promote breast cancer cell autophagy and apoptosis and enhance chemosensitivity of MCF-7 cells by inhibiting the PI3K/AKT/mTOR signaling pathway.

Autophagy inhibition enhances colorectal cancer apoptosis induced by dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor NVP-BEZ235

Phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling pathway performs a central role in tumorigenesis and is constitutively activated in many malignancies. As a novel dual PI3K/mTOR inhibitor currently undergoing evaluation in a phase I/II clinical trial, NVP-BEZ235 indicates a significant antitumor efficacy in diverse solid tumors, including colorectal cancer (CRC). Autophagy is a catabolic process that maintains cellular homeostasis and reduces diverse stresses through lysosomal recycling of the unnecessary and damaged cell components. This process is also observed to antagonize the antitumor efficacy of PI3K/mTOR inhibitor agents such as NVP-BEZ235, via apoptosis inhibition. In the present study, we investigated anti-proliferative and apoptosis-inducing ability of NVP-BEZ235 in SW480 cells and the crosstalk between autophagy and apoptosis in SW480 cells treated with NVP-BEZ235 in combination with an autophagy inhibitor. The results revealed that, NVP-BEZ235 effectively inhibit the growth of SW480 cells by targeting the PI3K/mTOR signaling pathway and induced apoptosis. The inhibition of autophagy with 3-methyladenine or chloroquine inhibitors in combination with NVP-BEZ235 in SW480 cells enhanced the apoptotic rate as componets to NVP-BEZ235 alone. In conclusion, the findings provide a rationale for chemotherapy targeting the PI3K/mTOR signaling pathway presenting a potential therapeutic strategy to enhance the efficacy of dual PI3K/mTOR inhibitor NVP-BEZ235 in combination with an autophagy inhibitor in CRC treatment and treatment of other tumors.

COL1A1 promotes metastasis in colorectal cancer by regulating the WNT/PCP pathway

Colorectal cancer (CRC) is the third leading cause of cancer-associated mortality, and is a major health problem. Collagen type I α 1 (COL1A1) is a major component of collagen type I. Recently, it was reported to be overexpressed in a variety of tumor tissues and cells. However, the function of COL1A1 in CRC remains unclear. Herein, the present study demonstrated that COL1A1 was upregulated in CRC tissues and the paired lymph node tissues. Transwell assays showed that COL1A1 promoted CRC cell migration in vitro. Moreover, it was revealed that COL1A1 levels were correlated with those of WNT/planar cell polarity (PCP) signaling pathway genes; inhibition of COL1A1 decreased the expression levels of Ras-related C3 botulinum toxin substrate 1-GTP, phosphorylated-c-Jun N-terminal kinase, and RhoA-GTP, all of which are key genes in the WNT/PCP signaling pathway. These results may indicate the mechanisms underlying the oncogenic role of COL1A1 in CRC. In summary, the present data indicated that COL1A1 may serve as an oncoprotein, and that it may be used as a potential therapeutic target in CRC.

Analysis of differentially expressed circular RNAs for the identification of a coexpression RNA network and signature in colorectal cancer: ZHANG et al.

Circular RNAs (circRNAs) play an important regulatory role in tumorigenesis. The aim of the present study was to analyze the circRNA expression network and elucidate its potential implications in colorectal cancer (CRC). The circRNA expression profile was analyzed in CRC tissues by RNA sequencing, and the functions of differentially expressed genes were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The circRNA network was predicted with bioinformatics. On the basis of the results, we identified 23 differentially expressed circRNAs in CRC; GO and KEGG analyses demonstrated that the changes in circRNAs were mainly associated with regulation of biological and metabolic processes through binding to other molecules. In addition, based on the predicted coexpression network, we identified a hub circRNA, hsa_circ_0009022. Subsequently, the results of sequencing were confirmed by reverse transcription‐quantitative polymerase chain reaction, and hsa_circ_0000826 was found to be downregulated in CRC. Taken together, these findings indicate a set of differentially expressed circRNAs that may serve as a candidate diagnostic biomarker and a promising therapeutic target in CRC.

COL1A1: A potential therapeutic target for colorectal cancer expressing wild-type or mutant KRAS

Colorectal cancer (CRC) treatment primarily relies on chemotherapy along with surgery, radiotherapy and, more recently, targeted therapy at the late stages. However, chemotherapeutic drugs have high cytotoxicity, and the similarity between the effects of these drugs on cancerous and healthy cells limits their wider use in clinical settings. Targeted monoclonal antibody treatment may compensate for this deficiency. Epidermal growth factor receptor (EGFR)-targeted drugs have a positive effect on CRC with intact KRAS proto-oncogene GTPase (KRAS or KRASWT), but may be ineffective or harmful in patients with KRAS mutations (KRASMUT). Therefore, it is important to identify drug target genes that are uniformly effective with regards to KRASWT and KRASMUT CRC. The present study performed gene expression analysis, and identified 294 genes upregulated in KRASWT and KRASMUT CRC samples. Collagen type I α 1 (COL1A1) was identified as the hub gene through STRING and Cytoscape analyses. Consistent with results obtained from Oncomine, a cancer microarray database and web-based data-mining platform, it was demonstrated that the expression of COL1A1 was significantly upregulated in CRC tissues and cell lines regardless of KRAS status. Inhibition of COL1A1 in KRASWT and KRASMUT CRC cell lines significantly decreased cell proliferation and invasion. In addition, increased COL1A1 expression in CRC was significantly associated with serosal invasion, lymph metastases and hematogenous metastases. Taken together, the findings of the present study indicated that COL1A1 may serve as a candidate diagnostic biomarker and a promising therapeutic target for CRC.

FGF18 Enhances Migration and the Epithelial-Mesenchymal Transition in Breast Cancer by Regulating Akt/GSK3β/Β-Catenin Signaling

Background/Aims: Fibroblast growth factors (FGFs) and their high-affinity receptors contribute to autocrine and paracrine growth stimulation in several human malignant tumors, including breast cancer. However, the mechanisms underlying the carcinogenic actions of FGF18 remain unclear. Methods: The transcription level of FGF18 under the hypoxic condition was detected with quantitative PCR (qPCR). A wound-healing assay was performed to assess the role of FGF18 in cell migration. A clonogenicity assay was used to determine whether FGF18 silencing affected cell clonogenicity. Western blotting was performed to investigate Akt/GSK3β/β-catenin pathway protein expression. Binding of β-catenin to the target gene promoter was determined by chromatin immunoprecipitation (ChIP) assays. Results: FGF18 promoted the epithelial-mesenchymal transition (EMT) and migration in breast cancer cells through activation of the Akt/GSK3β/β-catenin pathway. FGF18 increased Akt-Ser473 and -Thr308 phosphorylation, as well as that of GSK3β-Ser9. FGF18 also enhanced the transcription of proliferation-related genes (CDK2, CCND2, Ki67), metastasis-related genes (TGF-β, MMP-2, MMP-9), and EMT markers (Snail-1, Snail-2, N-cadherin, vimentin, TIMP1). β-catenin bound to the target gene promoter on the ChIP assay. Conclusion: FGF18 contributes to the migration and EMT of breast cancer cells following activation of the Akt/GSK3β/β-catenin pathway. FGF18 expression may be a potential prognostic therapeutic marker for breast cancer.

Nestin expression involves invasiveness of esophageal carcinoma and its downregulation enhances paclitaxel sensitivity to esophageal carcinoma cell apoptosis

Paclitaxel has been generally used to treat primary and metastatic esophageal carcinoma. It has been shown that nestin is highly expressed in esophageal carcinoma and that there is a strong association of nestin expression with poor prognosis in esophageal carcinoma patients. In this study, using immunohistochemistry, in situ hybridization and Western blotting we demonstrated that nestin was overexpressed in the invasive esophageal carcinoma. To further elucidate whether nestin inhibition could enhance paclitaxel sensitivity to esophageal carcinoma cells, we applied nestin siRNA in esophageal squamous cell carcinoma Eca-109 cells. Flow cytometry and TUNEL staining both showed that combination of paclitaxel treatment and nestin knockdown resulted in greater induction of apoptosis of esophageal carcinoma cells as compared with the cells transfected with control siRNA (also treated with paclitaxel). This study indicates that nestin knockdown enhances chemotherapeutic sensitivity of paclitaxel to esophageal carcinoma, and suggests that silencing of nestin could be a valuble therapeutic approach for enhancing drug sensitivity and thereby improving the treatment outcome of esophageal carcinoma patients.Paclitaxel has been generally used to treat primary and metastatic esophageal carcinoma. It has been shown that nestin is highly expressed in esophageal carcinoma and that there is a strong association of nestin expression with poor prognosis in esophageal carcinoma patients. In this study, using immunohistochemistry, in situ hybridization and Western blotting we demonstrated that nestin was overexpressed in the invasive esophageal carcinoma. To further elucidate whether nestin inhibition could enhance paclitaxel sensitivity to esophageal carcinoma cells, we applied nestin siRNA in esophageal squamous cell carcinoma Eca-109 cells. Flow cytometry and TUNEL staining both showed that combination of paclitaxel treatment and nestin knockdown resulted in greater induction of apoptosis of esophageal carcinoma cells as compared with the cells transfected with control siRNA (also treated with paclitaxel). This study indicates that nestin knockdown enhances chemotherapeutic sensitivity of paclitaxel to esophageal carcinoma, and suggests that silencing of nestin could be a valuble therapeutic approach for enhancing drug sensitivity and thereby improving the treatment outcome of esophageal carcinoma patients.

RETRACTED: Pigment epithelium derived factor play a positive role in bone mineralization of osteoblasts derived from diabetic patients

Pigment epithelium-derived factor (PEDF) is a multifunctional secreted protein which plays important role in anti-angiogenic, anti-tumorigenic, as well as involves in the metabolism and regeneration of bone. In this study, our aim is to investigate the role of PEDF in regulating mineralization of osteoblasts from diabetic patients (DP). We isolated and cultured osteoblasts derived from DP and non-diabetic patients (NDP), in order to analyze the variable differences via gene expression and calcification assay in vitro. Gene expression analysis and alizarin red S staining revealed that osteoblasts from DP exhibited defective mineralization. PEDF and vascular endothelial growth factor (VEGF) levels were lower in osteoblasts from DP than those from NDP. Interestingly, exogenous PEDF could upregulate the gene expression levels of VEGF and osteoblast-related genes, further to restore mineralization ability in osteoblasts from DP. Our results demonstrated that PEDF played a positive role in maintaining bone development in diabetic osteoblasts, therefore, we confidently believe that PEDF may be a promising cytokine to consider in development of treatments for diabetic bone diseases.