MiRNA-146b-5p upregulates migration and invasion of different Papillary Thyroid Carcinoma cells

Abstract

BackgroundTumor invasiveness is directly related to the ability of tumor cells to migrate and invade surrounding tissues, usually degrading extracellular matrix. Despite significant progress in the knowledge about migration and invasion, there is much more to elucidate about their regulatory mechanisms, especially in cancer cells. MicroRNAs (miRs) were recently described as important regulators of migration. Differential expression of miRs in cancer is frequently associated with progression, invasion and metastasis. In papillary thyroid carcinoma (PTC), miR-146b-5p is highly expressed and positively correlated to the degree of malignancy.MethodsThis study aimed to investigate the role of miR-146b-5p on the migratory and invasive behaviors of thyroid cells, using a non tumor rat thyroid follicular cell line (PCCl3) transfected with the miR-146b-5p genomic region, and two PTC cell lines (TPC-1 and BCPAP, bearing distinct oncogenic backgrounds), which express high levels of miR-146b-5p, after miR-146b inhibition by antagomiR and miR-146b overexpression by mimics-miR. Migration and invasion were studied by time-lapse and transwell assays (with and without Matrigel®). Gelatin degradation assays were also employed, as well as F-actin staining.ResultsMigration and invasion of PCCl3 were increased 2-3x after miR-146b-5p overexpression (10X) and large lamellipodia were evident in those cells. After miR-146b-5p inhibition, TPC-1 and BCPAP migration and invasion were significantly reduced, with cells showing several simultaneous processes and low polarity. Gelatin degradation was inhibited in TPC-1 cells after inhibition of miR-146b-5p, but was unaffected in BCPAP cells, which did not degrade gelatin. The inhibition of miR-146b-5p in PCCl3 also inhibited migration and invasion, and additional (exogenous) overexpression of this miR in TPC-1 and BCPAP cells increased migration and invasion, without effects on cell morphology or gelatin degradation. The overexpression of SMAD4 in BCPAP cells, a validated target of miR-146b-5p and key protein in the TGF-β signaling pathway, inhibited migration similarly to the effects observed with the antagomiR 146b-5p.ConclusionsmiR-146b-5p positively regulates migration and invasion of thyroid normal and tumor follicular cells (independently from their original mutation, either BRAF or RET/PTC), through a mechanism that involves the actin cytoskeleton but not an increased capacity of matrix degradation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2146-z) contains supplementary material, which is available to authorized users.

MicroRNA-146b: A Novel Biomarker and Therapeutic Target for Human Papillary Thyroid Cancer

“…We also confirmed that miR-146b promotes aggressive tumor characteristics in PTC by suppressing IRAK1 expression and that restoration of IRAK1 expression reversed this outcome. In agreement with our findings, Lima et al [38] reported that miR-146b positively regulates migration and invasion activity both in normal or cancer thyroid lines through the action of stimulating actin cytoskeleton functions. In addition, miR-146b and its related target genes play an important role in other thyroid neoplasms.…”

Differences in miRNA expression profiles between wild-type and mutated NIFTPs

“…Cluster 1: 11 mutated and 1 wild-type NIFTP; cluster 2: 7 wild-type NIFTPs. be the deregulation of SMAD4 and/or TGFB signaling, as recently reported by Lima and coworkers (Lima et al 2016). Unsupervised hierarchical clustering analysis allowed us to discover that the wild-type NIFTPs had a clearly distinct miRNA expression profile compared with the RAS-or BRAF-mutated NIFTPs.…”

Circulating microRNA146b‐5p is superior to C‐reactive protein as a novel biomarker for monitoring inflammatory bowel disease

“…It is highly expressed in rheumatoid arthritis synovial tissues and can be induced by stimulation with tumour necrosis factor α and interleukin‐1 β . Moreover, upregulation of miR‐146b‐5p is associated with cell proliferation, aggressiveness, and poor prognosis as an oncogene in papillary thyroid carcinoma, lung cancer, and gastrointestinal malignant tumour . In IBD, miR‐146a expression was elevated in the colonic mucosa of both paediatric and adult patients compared to in healthy controls .…”