Restoration of miRNA-143 Expression Inhibits Growth and Migration of MKN-45 Gastric Cancer Cell Line.

Purpose: Gastric cancer (GC) is one of the main causes of death from diseases, especially in developing countries. MicroRNAs (miRNAs) are important modulators of the messenger RNAs expression. Among these miRNAs, MiR-143 is a tumor suppressor miRNA and its irregular expression has been revealed in a diversity of malignancies such as GC. Methods: In this study, we have attempted to restore the miR-143 expression in MKN-45 cells by introducing pCMV-miR-143 plasmid vectors. The consequences of exogenous expression of miR-143 on cell proliferation and migration were assessed by MTT and scratch tests, respectively. In addition, the DAPI staining assay was applied for apoptosisquantification. Following miR-143 transfection, the changes in K-Ras, C-Myc, MMP9, Bax, Caspase-3, and Caspase-9 mRNA levels were assessed. Results: The results indicated that the enhanced expression of miR-143 had negative effects on MKN-45 cells proliferation and invasion. Moreover, decreased expressions of K-Ras, MMP9, and C-Myc and up-regulation of Bax, Caspase-3, and Caspase-9 as downstream targets of miR-143 were recognized. Conclusion: These experimental results indicate that reversing the miR-143 expression, by novel techniques, including miRNA replacement could be considered as an efficient approach to reduce cell survival and metastasis.

Overexpression of miRNA-145 induces apoptosis and prevents proliferation and migration of MKN-45 gastric cancer cells.

MiR-145 is a tumor suppressor miRNA that its ubiquitously expressed in the body but in numerous types of cancers such as GC, its expression became reduced or sometimes ceased in many subjects. This study aimed at restoring the function of the miR-145 in MKN-45 cells and investigating the function of this miRNA in proliferation, apoptosis, and migration of GC cells. MKN-45 cells were transfected using the PCMV-miR-145 plasmid vector. The MTT, DAPI staining, and wound healing assays were applied to estimate the impacts of ectopic expression of miR-145 in vitro. Moreover, alterations in the expression levels of K-Ras, c-Myc, caspase-3, caspase-9, Bax, Bcl-2, and MMP-9 mRNA were measured by qRT-PCR analysis. The findings designated that high expression of miR-145 reduced the proliferation and migration and increased the apoptosis of the MKN-45 cells. These effects occur with concurrent suppression of c-Myc, K-Ras, Bcl-2, and MMP-9 as well as induction of caspase-3, caspase-9, and Bax expression. Exogenous miR-145 influences multiple oncogenic pathways and can be regarded as a promising avenue of future therapeutic interventions for GC therapy.

miRNA-143 replacement therapy harnesses the proliferation and migration of colorectal cancer cells in vitro.

miR-143 is a tumor suppressor miRNA which its downregulation is frequently reported in colorectal cancer (CRC). This miRNA is a negative regulator of K-RAS, c-MYC, BCL-2, and MMP-9 genes which are engaged in tumor growth and metastasis. In the present study, miR-143 restoration was performed by transfection of the pCMV-miR-143 vector into the SW-480 CRC cells. Subsequently, alterations in proliferative and migratory potential of the cells were investigated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and wound-healing assays, respectively. Moreover, to detect apoptosis incidence in the transfected cells, 4',6-diamidino-2-phenylindole (DAPI) staining was used. Furthermore, mRNA levels of c-MYC, K-RAS, MMP-9, and BCL-2, as potential targets of miR-143, were assessed by quantitative Real-Time PCR (qRT-PCR). Also the expression levels of c-MYC, K-RAS, and MMP-9 proteins were investigated by the western blot analysis. Finally, the ratio of BAX to BCL-2 expression, as a potential marker of the response to apoptosis stimuli, was compared between the control and test groups. Furthermore, the trypan blue test was performed to determine the cell viability in cell suspension. According to the results, a decreased viability and migratory potential was observed for the miR-143 receiving cells. The DAPI staining also confirmed the occurrence of apoptosis. Moreover, BCL-2, K-RAS, MMP-9, and c-MYC mRNAs were significantly downregulated in the miR-143 grafted cells. The BAX/BCL-2 ratio also indicated a notable increase in the cells with miR-143 overexpression. In brief, miR-143 replacement could be considered as an effective strategy for the management of CRC and attenuating its invasive features.

Treating cancer with microRNA replacement therapy: A literature review.

microRNAs (miRNAs) are small non-coding RNAs that regulate gene expression post-transcriptionally by interfering with the translation of one or more target mRNAs. The unique miRNA sequences are involved in many physiological and pathological processes. Dysregulation of miRNAs contributes to the pathogenesis of all types of cancer. Notably, the diminished expression of tumor suppressor miRNAs, such as members of the Let-7 and miR-34 family, promotes tumor progression, invasion and metastasis. The past lustrum in particular, has witnessed substantial improvement of miRNA replacement therapy. This approach aims to restore tumor suppressor miRNA function in tumor cells using synthetic miRNA mimics or miRNA expression plasmids. Here, we provide a comprehensive review of recent advances in miRNA replacement therapy for treatment of cancer and its advantages over conventional gene therapy. We discuss a wide variety of delivery methods and vectors, as well as obstacles that remain to be overcome. Lastly, we review efforts to reverse epigenetic alterations, which affect miRNA expression in cancer cells, and the promising observation that restoring miRNA function re-sensitizes resistant tumor cells to chemotherapeutic drugs. The fact that various miRNA replacement therapies are currently in clinical trial demonstrates the great potential of this approach to treat cancer.