The expression of miR-155 was significantly upregulated in the CRC tissues and the high expression of miR-155 correlated with an advanced clinical stage, lymph node and distant metastases.
In the present study, we investigated the effects of miR-155 on pancreatic cancer cell invasion and migration in vitro, underlying gene expression, expression of miR-155 and its target genes in pancreatic cancer tissues, and their association with metastasis and clinical stage. miR-155 mimics and an inhibitor were transfected into Panc-1 and Capan-2 cells in order to regulate the expression of miR-155. qPCR and western immunoblotting were performed in order to detect gene expression.
A vast number of miRNAs, including the well-studied miR-21, miR-155 and miR-34, has been shown to regulate PDAC growth, invasion and metastasis in vitro and in vivo by targeting members of key signaling pathways.
The miRNA microarray assay revealed miR-155 to be highly expressed and biologically active in chordoma. miR-155 expression in chordoma tissues was significantly elevated, and this expression correlated significantly with disease stage (p = 0.036) and the presence of metastasis (p = 0.035). miR-155 expression also correlated significantly with poor outcomes for chordoma patients (hazard ratio, 5.32; p = 0.045).
Additionally, miR-155-5p overexpression increased metastasis- and anti-apoptosis-related protein expression and decreased pro-apoptosis-related protein expression, while forced CTHRC1 expression conserved the expression of these proteins.
Additionally, the downregulation of miR-155 expression in gastric carcinoma cell lines was able to significantly decrease the expression of VEGF, MMP2 and MMP9, thereby inhibiting the invasion and metastasis of gastric carcinoma cells.
Taken together, our study provided the first compelling evidence that ING4 can suppress human HCC growth and metastasis to a great extent via a NF-κB/miR-155/FOXO3a pathway.
The study indicated that transfection of miR-155-5p mimic significantly suppressed cell proliferation, migration and invasion of A549 cells, whereas its inhibition significantly promoted cell proliferation, migration and invasion of A549 cells, suggesting a potential therapeutic application of miR-155-5p in controlling lung cancer metastasis.
We found that miR-155 expression was markedly up-regulated in cervical cancer tissues and correlated with FIGO stage, lymph nodes metastasis, vascular invasion and HPV.
Sevoflurane inhibited migration and invasion, while enhanced cell apoptosis by downregulating miR-155 in PTC cells, suggesting important clinical implications for anesthetic agents to prevent the metastasis in PTC.
Before PRFA, tumor suppressor let-7a and miR-34a were downregulated whereas oncomiR miR-21 was upregulated in primary tumors, and let-7a and miR-126 levels were downregulated whereas oncomiRs miR-21, miR-155 and miR-17-5p/miR-20b levels were upregulated in secondary tumors.
The results identify miR-155-mediated loss of C/EBPβ as a mechanism, which promotes breast cancer progression by shifting the TGF-β response from growth inhibition to EMT, invasion and metastasis.
Expression of miR-9, miR-10b, miR-145, and miR-155, 4 miRNAs previously shown to play roles in metastasis in other tumor types, was compared in lymph node (LN)-positive NSCLC versus LN-negative NSCLC.
In breast cancer patients, the changes in the levels of total RNA (P = 0.0001), miR10b (P = 0.01), miR34a (P = 0.003) and miR155 (P = 0.002) correlated with the presence of overt metastases.
The effect of miR-155-5p on cervical carcinoma cell growth and metastasis in vivo was investigated using xenograft model and experimental lung metastasis model.
Taken together, these results show that miR-155-5p positively regulates RhoA mRNA levels and translation as well as cell migration in serum starved colon cancer cells and indicate that targeting miR-155-5p might be a useful strategy to antagonize colon cancer metastasis.
Furthermore, using functional assays and The Cancer Genome Atlas (TCGA) Lung Adenocarcinoma (LUAD) dataset, we found that rs767649 variant allele could increase the transcriptional activity of miR-155, which in turn facilitated tumor growth and metastasis by inhibiting HBP1, TJP1, SMAD5 and PRKAR1A expression.