TGF-β1 alters microRNA profile in human gastric cancer cells

Role of miR-100-5p and CDC25A in breast carcinoma cells

OBJECTIVE

To inquiry about mechanism of miR-100-5p/CDC25A axis in breast carcinoma (BC), thus offering a new direction for BC targeted treatment.

METHODS

qRT-PCR was employed to explore miR-100-5p and CDC25A mRNA levels. Western blot was employed for detecting protein expression of CDC25A. Targeting relationship of miR-100-5p and CDC25A was verified by dual-luciferase assay. In vitro experiments were used for assessment of cell functions.

RESULTS

In BC tissue and cells, miR-100-5p was significantly lowly expressed (P < 0.05) while CDC25A was highly expressed. Besides, miR-100-5p downregulated CDC25A level. miR-100-5p had a marked influence on the prognosis of patients. The forced miR-100-5p expression hindered BC cell proliferation, migration and invasion, and facilitated cell apoptosis. Upregulated miR-100-5p weakened promotion of CDC25A on BC cell growth.

CONCLUSION

Together, these findings unveiled that CDC25A may be a key target of miR-100-5p that mediated progression of BC cells. Hence, miR-100-5p overexpression or CDC25A suppression may contribute to BC diagnosis.

miR‑29b suppresses proliferation and induces apoptosis of hepatocellular carcinoma ascites H22 cells via regulating TGF‑β1 and p53 signaling pathway

MicroRNA (miR)‑29b is a key tumor regulator. It can inhibit tumor cell proliferation, induce apoptosis, suppress tumor invasion and migration, thus delaying tumor progression. Our previous studies revealed an increased level of miR‑29b in hepatoma 22 (H22) cells in ascites tumor‑bearing mice. The present study investigated the effect of miR‑29b on proliferation and apoptosis of hepatocellular carcinoma ascites H22 cells and its association with the transforming growth factor‑β1 (TGF‑β1) signaling pathway and p53‑mediated apoptotic pathway. Briefly, H22 cells were transfected with miR‑29b‑3p (hereinafter referred to as miR‑29b) mimic or miR‑29b inhibitor. MTS cell proliferation assay and flow cytometry were used to analyze cell viability and apoptosis. The expression change of the TGF‑β1 signaling pathway and p53‑mediated apoptotic pathway were detected by reverse transcription‑quantitative PCR, western blotting and immunofluorescence. Furthermore, cells were treated with exogenous TGF‑β1 and TGF‑β1 small interfering RNA to evaluate the crosstalk between TGF‑β1 and p53 under miR‑29b regulation. The overexpression of miR‑29b decreased cell viability, increased cell apoptosis, activated the TGF‑β1 signaling pathway and p53‑mediated apoptotic pathway. Conversely, these effects were reversed by the miR‑29b inhibitor. Moreover, the effect of miR‑29b mimic was further increased after treating cells with exogenous TGF‑β1. The activation of the TGF‑β1 signaling pathway and p53‑mediated apoptotic pathway induced by miR‑29b overexpression were reversed by TGF‑β1 inhibition. In summary, these data indicated that miR‑29b has an important role in proliferation and apoptosis of H22 cells by regulating the TGF‑β1 signaling pathway, the p53‑dependent apoptotic pathway, and the crosstalk between TGF‑β1 and p53.

Role and clinical significance of TGF‑β1 and TGF‑βR1 in malignant tumors (Review)

The appearance and growth of malignant tumors is a complicated process that is regulated by a number of genes. In recent years, studies have revealed that the transforming growth factor-β (TGF-β) signaling pathway serves an important role in cell cycle regulation, growth and development, differentiation, extracellular matrix synthesis and immune response. Notably, two members of the TGF-β signaling pathway, TGF-β1 and TGF-β receptor 1 (TGF-βR1), are highly expressed in a variety of tumors, such as breast cancer, colon cancer, gastric cancer and hepatocellular carcinoma. Moreover, an increasing number of studies have demonstrated that TGF-β1 and TGF-βR1 promote proliferation, migration and epithelial-mesenchymal transition of tumor cells by activating other signaling pathways, signaling molecules or microRNAs (miRs), such as the NF-κB signaling pathway and miR-133b. In addition, some inhibitors targeting TGF-β1 and TGF-βR1 have exhibited positive effects in in vitro experiments. The present review discusses the association between TGF-β1 or TGF-βR1 and tumors, and the development of some inhibitors, hoping to provide more approaches to help identify novel tumor markers to restrain and cure tumors.

SUFU mediates EMT and Wnt/β-catenin signaling pathway activation promoted by miRNA-324-5p in human gastric cancer

The poor prognosis of late gastric carcinomas (GC) underscores the necessity to identify novel biomarkers for earlier diagnosis and effective therapeutic targets. MiRNA-324-5p has been shown to be over-expressed in GC, however the biological function of miRNA-324-5p implicated in gastric cancer and its downstream targets were not well understood. Wnt/β-catenin signaling pathway is aberrantly regulated in GC. We sought to explore if miRNA-324-5p promotes oncogenesis through modulating Wnt signaling and EMT. MiRNA-324-5p is highly expressed in GC based on qRT-PCR and TCGA data. In addition, in vitro cell proliferation, cell migration assays and in vivo animal exenograft were executed to show that miRNA-324-5p is an oncogenic miRNA in GC. MiRNA-324-5p activates Wnt signaling and induces EMT in GC. Further, SUFU was identified as a target of miRNA-324-5p confirmed by western blotting and luciferase assays. Spearson analysis and TCGA data indicate that the expression of SUFU is negatively associated with the expression of miRNA-324-5p. Rescue experiments were performed to determine if SUFU mediates the Wnt activation, EMT and oncogenic function of miRNA-324-5p. MiRNA-324-5p inhibitors plus SUFU siRNAs rescue partially the inhibitory effect on Wnt signaling and EMT caused by miRNA-324-5p inhibitors. Finally, the suppression of cell proliferation, migration, and colony formation ability induced by miRNA-324-5p inhibitors is alleviated by addition of SUFU siRNAs. In summary, miRNA-324-5p is overexpressed in vivo and exerts cell growth and migration-promoting effects through activating Wnt signaling and EMT by targeting SUFU in GC. It represents a potential miRNA with an oncogenic role in human gastric cancer.

Distinct prognostic values and antitumor effects of tumor growth factor β1 and its receptors in gastric cancer

Gastric cancer (GC) is one of the most common malignancies and is the second leading cause of cancer-associated mortality world-wide. In the present study, the prognostic value and antitumor effects of transforming growth factor β1 (TGFβ1) and its receptors in GC were explored. The online Kaplan-Meier plotter database was used to investigate the prognostic values of TGFβ1 and its receptors. The present study demonstrated that low mRNA expression levels of TGFβ1 and its 3 receptors, transforming growth factor β1 (TGFβR1), TGFβR2 and TGFβR3, was associated with improved overall survival time in patients with GC. Cell Counting Kit-8 and Transwell assays were used to confirm the effects of TGFβ1, TGFβR1, TGFβR2 and TGFβR3 on the proliferation, migration and invasiveness of the AGS and MKN45 GC cell lines. It was found that the knockdown of these genes blocked cell proliferation, migration and invasion in GC cells. To the best of our knowledge, the present study is the first to determine the role of TGFβR1 and TGFβR3 in GC cells. The results indicate that in addition to TGFβ1 and TGFβR2, TGFβR1 also plays a specific role in the occurrence and development of tumors. Thus, these markers may be considered as potential prognostic indicators in human GC. The findings of the present study indicate that not only TGFβ1 and TGFβR2, but also TGFβR1 is involved in the progression of GC. The findings of the present study provide new ideas and approaches for the treatment of patients with GC.

MicroRNA-193b regulates human ovarian cancer cell growth via targeting STMN1

Ovarian cancer is the eighth most common malignancy among women worldwide. Ovarian cancer exhibits no obvious symptoms in the early stage of tumorigenesis and currently, no effective methods for the early detection and treatment of ovarian cancer have been established. Therefore, the identification of novel targets is critical to the early diagnosis and clinical treatment of ovarian cancer. microRNAs (miRs) are small non-coding RNAs, which serve an important biological role in a number of physiological processes and in oncogenesis. Previous studies have reported that miRNA-193b is dysregulated in a variety of types of human cancer. However, the roles of miRNA-193b in human ovarian cancer has not been determined. The present study investigated the roles of miRNA-193b in human ovarian cancer cells. Reverse transcription-quantitative PCR results indicated that the expression of miRNA-193b in ovarian cancer cells was significantly down-regulated compared with non-malignant cells. Cell counting kit-8 results indicated that the up-regulation of miRNA-193b inhibited ovarian cancer cell proliferation and induced ovarian cancer cell apoptosis. The present study also indicated that stathmin 1 (STMN1) was a direct target of miRNA-193b, and the up-regulation of miRNA-193b significantly decreased the expression of STMN1 in ovarian cancer cells. In conclusion, the results demonstrated that miRNA-193b serves as a tumor suppressor in human ovarian cancer by inhibiting cell proliferation and inducing cell apoptosis. Therefore, the assessment of miRNA-193b may provide insight into a novel diagnostic biomarker and potential therapeutic target for patients with ovarian cancer.

miR193b Promotes Apoptosis of Gastric Cancer Cells via Directly Mediating the Akt Pathway

Gastric cancer (GC) is one of the most common and fatal malignancies worldwide. MicroRNAs (miRNAs) play a critical role in tumor initiation, proliferation, and metastasis of gastric cancer. miR193b has been identified as a tumor suppressor in a variety of tumor types; however, its role in gastric cancer is yet to be determined. Here, we found a significant downregulation of miR193b expression in both human gastric cancer tissues (p < 0.05) and human gastric cancer cell lines (p < 0.01). Furthermore, the expression level of miR193b correlated with the tumor type, tumor size, and clinical stage (p < 0.05). In vitro, miR193b overexpression inhibited cell survival and induced apoptosis in GC cell lines, indicating that miR193b plays a role in the development of gastric cancer. KRAS was verified as the target of miR193b, and KRAS overexpression attenuated miR193b-induced apoptosis (p < 0.05). Moreover, we found that the Akt pathway negatively regulated miR193b, also affecting apoptosis. Further analyses indicated that PIK3CA mutation and KRAS amplification are two mutually exclusive pathways (p < 0.01), and we hypothesize that both two pathways could result in the carcinogenic overactivation of KRAS. Thus, our results suggest that the Akt-miR193b-KRAS axis may act as a mechanism affecting apoptosis in gastric cancer cells.

LINC00152 down-regulated miR-193a-3p to enhance MCL1 expression and promote gastric cancer cells proliferation

The present work aimed to probe into the effect of long non-coding RNA (lncRNA) LINC00152 on gastric cancer (GC) cells proliferation by regulating miR-193a-3p and its target gene MCL1 Transfected si-LINC00152 was used to down-regulate LINC00152, and cells proliferation was measured by the cell counting kit-8 (CCK-8) assay. Cell apoptosis and cell cycle were analyzed by flow cytometry (FCM). Besides, we also detected the potential functional effects of differential expression of LINC00152 in vivo using nude mouse xenograft model. We overexpressed and downexpressed miR-193a-3p to study the in vitro effect of miR-193a-3p on GC cells proliferation and vitality. And MCL1 was silenced by shRNA to investigate the effect of MCL1 on proliferation of GC cells. In this research, LINC00152 was proven to have a higher expression level in GC tissues than in the adjacent normal tissues. GC cells proliferation was inhibited after LINC00152 was down-regulated. LINC00152 inhibited the expression of miR-193a-3p, which negatively regulated MCL1 In addition, GC cells proliferation was inhibited by cell transfection with shRNA-MCL1, and enhanced by transfection with miR-193a-3p mimics. Our study suggested that LINC00152 was overexpressed in GC tissues, and it down-regulated miR-193a-3p to enhance MCL1 expression thereby promoting GC cells proliferation.

Interplay between miR-574-3p and hnRNP L regulates VEGFA mRNA translation and tumorigenesis

MicroRNAs (miRNAs) and heterogeneous nuclear ribonucleoproteins (hnRNPs) are families of sequence-specific, posttranscriptional modulators of gene expression. Despite extensive mechanistic and functional studies on both regulatory classes, the interactions and crosstalk between them are largely unexplored. We have reported that competition between miR-297 and hnRNP L to bind a 3΄UTR-localized CA-rich element (CARE) of VEGFA mRNA regulates its translation. Here, we show that translation of VEGFA mRNA in human myeloid cells is dictated by a bi-directional interaction between miR-574-3p, a CA-rich microRNA, and hnRNP L. In normoxia, miR-574-3p, acting as a decoy, binds cytoplasmic hnRNP L and prevents its binding to the CARE and stimulation of VEGFA mRNA translation, simultaneously permitting miR-297-mediated translational silencing. However, in hypoxia, cytoplasmic accumulation of Tyr³⁵⁹-phosphorylated hnRNP L sequesters miR-574-3p, overcoming its decoy activity and seed sequence-dependent gene silencing activity. Ectopically expressed miR-574-3p binds multiple RNA recognition motif (RRM) domains of hnRNP L, synergizes with miR-297, reduces VEGFA mRNA translation, and triggers apoptosis, thereby suppressing tumorigenesis. Our studies establish a novel condition-dependent interplay between a miRNA and an hnRNP that regulates their functions in a bidirectional manner.

Filtered selection coupled with support vector machines generate a functionally relevant prediction model for colorectal cancer

Purpose

There has been considerable interest in using whole-genome expression profiles for the classification of colorectal cancer (CRC). The selection of important features is a crucial step before training a classifier.

Methods

In this study, we built a model that uses support vector machine (SVM) to classify cancer and normal samples using Affymetrix exon microarray data obtained from 90 samples of 48 patients diagnosed with CRC. From the 22,011 genes, we selected the 20, 30, 50, 100, 200, 300, and 500 genes most relevant to CRC using the minimum-redundancy–maximum-relevance (mRMR) technique. With these gene sets, an SVM model was designed using four different kernel types (linear, polynomial, radial basis function [RBF], and sigmoid).

Results

The best model, which used 30 genes and RBF kernel, outperformed other combinations; it had an accuracy of 84% for both ten fold and leave-one-out cross validations in discriminating the cancer samples from the normal samples. With this 30 genes set from mRMR, six classifiers were trained using random forest (RF), Bayes net (BN), multilayer perceptron (MLP), naïve Bayes (NB), reduced error pruning tree (REPT), and SVM. Two hybrids, mRMR + SVM and mRMR + BN, were the best models when tested on other datasets, and they achieved a prediction accuracy of 95.27% and 91.99%, respectively, compared to other mRMR hybrid models (mRMR + RF, mRMR + NB, mRMR + REPT, and mRMR + MLP). Ingenuity pathway analysis was used to analyze the functions of the 30 genes selected for this model and their potential association with CRC: CDH3, CEACAM7, CLDN1, IL8, IL6R, MMP1, MMP7, and TGFB1 were predicted to be CRC biomarkers.

Conclusion

This model could be used to further develop a diagnostic tool for predicting CRC based on gene expression data from patient samples.

Dysregulation of non-coding RNAs in gastric cancer

Gastric cancer (GC) is one of the most common cancers in the world and a significant threat to the health of patients, especially those from China and Japan. The prognosis for patients with late stage GC receiving the standard of care treatment, including surgery, chemotherapy and radiotherapy, remains poor. Developing novel treatment strategies, identifying new molecules for targeted therapy, and devising screening techniques to detect this cancer in its early stages are needed for GC patients. The discovery of non-coding RNAs (ncRNAs), primarily microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), helped to elucidate the mechanisms of tumorigenesis, diagnosis and treatment of GC. Recently, significant research has been conducted on non-coding RNAs and how the regulatory dysfunction of these RNAs impacts the tumorigenesis of GC. In this study, we review papers published in the last five years concerning the dysregulation of non-coding RNAs, especially miRNAs and lncRNAs, in GC. We summarize instances of aberrant expression of the ncRNAs in GC and their effect on survival-related events, including cell cycle regulation, AKT signaling, apoptosis and drug resistance. Additionally, we evaluate how ncRNA dysregulation affects the metastatic process, including the epithelial-mesenchymal transition, stem cells, transcription factor activity, and oncogene and tumor suppressor expression. Lastly, we determine how ncRNAs affect angiogenesis in the microenvironment of GC. We further discuss the use of ncRNAs as potential biomarkers for use in clinical screening, early diagnosis and prognosis of GC. At present, no ideal ncRNAs have been identified as targets for the treatment of GC.

Role of the Wnt/β-catenin pathway in gastric cancer: An in-depth literature review

Gastric cancer remains one of the most common cancers worldwide and one of the leading cause for cancer-related deaths. Gastric adenocarcinoma is a multifactorial disease that is genetically, cytologically and architecturally more heterogeneous than other gastrointestinal carcinomas. The aberrant activation of the Wnt/β-catenin signaling pathway is involved in the development and progression of a significant proportion of gastric cancer cases. This review focuses on the participation of the Wnt/β-catenin pathway in gastric cancer by offering an analysis of the relevant literature published in this field. Indeed, it is discussed the role of key factors in Wnt/β-catenin signaling and their downstream effectors regulating processes involved in tumor initiation, tumor growth, metastasis and resistance to therapy. Available data indicate that constitutive Wnt signalling resulting from Helicobacter pylori infection and inactivation of Wnt inhibitors (mainly by inactivating mutations and promoter hypermethylation) play an important role in gastric cancer. Moreover, a number of recent studies confirmed CTNNB1 and APC as driver genes in gastric cancer. The identification of specific membrane, intracellular, and extracellular components of the Wnt pathway has revealed potential targets for gastric cancer therapy. High-throughput “omics” approaches will help in the search for Wnt pathway antagonist in the near future.

MicroRNAs related to invasiveness and metastasis of gastric cancer

Metastasis plays an important role in the prognosis of patients with cancer. It is known that several steps are necessary for clonal cells to disseminate from their primary tumor site and colonize distant tissues. It will provide useful insights for effective treatment of cancer to investigate the molecular actors regulating this process. MicroRNAs, 19-25 nt in length, are a class of non-coding RNA, and they can result in degradation of specific mRNAs or inhibit their translation. They have been known as negative regulators of gene expression and are involved in many biological processes, including cell growth, differentiation and apoptosis. The relationship between the abnormal expression of microRNAs and tumors has been widely studied. Some recent research has clarified the role of microRNAs in tumor invasion and metastases. This paper reviews the recent progress in research of microRNAs related to invasiveness and metastasis of gastric cancer.