Determining The Role of MicroRNAs in Self-Renewal, Metastasis and Resistance to Drugs in Human Gastric Cancer Based on Data Mining Approaches: A Systematic Review.

Gastric cancer (GC) is one of the leading causes of cancer-related deaths worldwide. The major problems of patients with GC are the lack of proper response to the treatment, drug resistance and metastasis attributed to the presence of a subpopulation of cells inside the tumour that are called cancer stem cells (CSCs). In addition, deregulation of microRNAs (miRNAs) has been reported in different stages of GC. The aim of the present study is to determine and introduce miRNAs that contribute to regulation of stemness, metastasis and drug resistance in GC. A systematic review, we conducted data mining of available datasets and a review of previous studies to select miRNAs that target stemness, epithelial-mesenchymal transition (EMT) and drug resistance. All selected miRNAs were analysed by R software to find a common miRNA target for all three processes. Then, the target prediction of miRNAs and their related signalling pathways were obtained by using bioinformatics tools, ONCO.IO and KEGG databases, respectively. We identified seven miRNAs (miR-34a, miR-23a, miR-27a, miR-30a, miR-19b, miR-107, miR-100) from our searching approach. These miRNAs regulate pathways that contribute to stemness, EMT and drug resistance in GC. Four (miR- 34a, miR-23a, miR-30a, and miR-100) had significant interactions with each other and 52 target genes among them, from which MYC, CDK6, NOTCH1, NOTCH2, SIRT1, CD44, CD24, and AXL were involved in the regulation of several biological processes. These data suggest that the three significant properties can be regulated by common miRNAs (hsa-miR-34a, hsa-miR-23a, hsa-miR-30a and hsa-miR-100). Hence, targeting selected miRNAs or their targets might be helpful to stop tumour growth and metastasis development, and increase tumour sensitivity to chemotherapy agents. This signature can also be assumed for early detection of metastasis or drug resistance. However, there should be additional experimentation to validate these results.

An integrated analysis to predict micro-RNAs targeting both stemness and metastasis in human gastric cancer.

BACKGROUND AND AIM: Cancer stem cells (CSCs), a subpopulation of tumor cells, assess the capacity of self-renewal, metastasis, and therapeutic resistance. Regulation of CSCs and their epithelial to mesenchymal transition (EMT) potential is one of the promising strategies to eliminate cancer or to inhibit metastasis. Micro-RNAs (miRNAs) as regulators of several cell properties, such as self-renewal, metastasis, and resistance to the drug, could be proper targets in cancer diagnosis and therapy. The aim of the present study is to select common miRNAs targeting both self-renewal and metastasis in gastric cancer. METHODS: Stemness-related and EMT-related genes were selected by literature mining. The common miRNAs targeting genes were chosen using different databases and r programming language. The expression pattern of selected miRNAs and genes was evaluated in gastrospheres-as a gastric CSC model-and gastric tumor biopsies. RESULTS: Based on the integrated analysis, six miRNAs common to both stemness and metastasis were identified. miR-200c-3p and miR-520c-3p overexpressed in MKN-45 gastrospheres and grade III tumors. In AGS spheres, however, miR-520c-3p and miR-200c-3p upregulation and miR-34a-5p downregulation were similar to grade II tumors. Interestingly, miR-200c-3p and miR-520c-3p indicated a positive correlation with OCT4 and NOTCH1 expression in grade III tumors and MKN-45 spheres. Protein-protein network revealed that the EMT acquisition can be induced by stemness activation through intermediated core-regulatory genes, including CTNNB1, CTNND1, MAML1, KAT2A, and MAML3. CONCLUSION: The upregulation of mir-200c-3p and mir-520c-3p could effect on stemness and metastasis in gastric cancer as well as gastric CSCs. Therefore, they can be used as diagnosis and prognostic factors.

An integrated analysis to predict micro-RNAs targeting both stemness and metastasis in breast cancer stem cells.

Several evidences support the idea that a small population of tumour cells representing self-renewal potential are involved in initiation, maintenance, metastasis, and outcomes of cancer therapy. Elucidation of microRNAs/genes regulatory networks activated in cancer stem cells (CSCs) is necessary for the identification of new targets for cancer therapy. The aim of the present study was to predict the miRNAs pattern, which can target both metastasis and self-renewal pathways using integration of literature and data mining. For this purpose, mammospheres derived from MCF-7, MDA-MB231, and MDA-MB468 were used as breast CSCs model. They had higher migration, invasion, and colony formation potential, with increasing in stemness- and EMT-related genes expression. Our results determined that miR-204, -200c, -34a, and -10b contemporarily could target both self-renewal and EMT pathways. This core regulatory of miRNAs could increase the survival rate of breast invasive carcinoma via up-regulation of OCT4, SOX2, KLF4, c-MYC, NOTCH1, SNAI1, ZEB1, and CDH2 and down-regulation of CDH1. The majority of those target genes were involved in the regulation of pluripotency, MAPK, WNT, Hedgehog, p53, and transforming growth factor ß pathways. Hence, this study provides novel insights for targeting core regulatory of miRNAs in breast CSCs to target both self-renewal and metastasis potential and eradication of breast cancer.