Abstract 528: The modulatory role of miRNA 126 in thyroid cancer angiogenesis
Authors: Salajegheh Ali , Vosgha Haleh , Rahman Md. Atiqur , Gopalan Vinod , Smith Robert Anthony , Lam Alfred King-Yin 
Published: May 2015

MicroRNAs (miRNAs) have been described as one of the novel class of molecular regulators. Due to the crucial role miRNA-126 plays in angiogenesis, as well as the necessity of angiogenesis in malignancy, miRNA-126 has been found in association with several types of cancer.

Vascular endothelial growth factor (VEGF) promotes angiogenesis and is a potent mediator of vascular permeability, as well as being a key mediator of tumour-associated neoangiogenesis and progression.

In this study, we have investigated the role of miRNA-126, VEGF-A and their impact on angiogenesis in thyroid cancers.

51 conventional papillary thyroid carcinomas, 37 follicular variant of papillary thyroid carcinomas, 13 undifferentiated thyroid carcinomas, 13 matched lymph nodes metastasis and 21 normal thyroid tissues obtained from non-cancer adjacent to benign lesions were recruited as controls.

Firstly, extracted miRNAs from selected samples were loaded on a miRNA microarray chip developed by Agilent (Agilent Technologies, Inc., Santa Clara, CA, USA) using a pooling method to confirm the expression differences of miRNAs including miRNA-126. Then, miRNA-126 and VEGF-A was tested in individual samples using real-time PCR. In addition, 2 papillary thyroid cancer cell lines (K1 and B-CPAP) and a normal thyroid cell line (Nthy-ori 3-1) were used for the exogenous manipulation of the miRNA-126 and investigation of its effect on VEGF-A expression. The expression of VEGF-A were then measured by immunofluorescence and western blot techniques.

The expression of miRNA-126 was noticeably higher in the pool of papillary thyroid carcinoma with metastasis. Using real time PCR, miRNA-126 and VEGF-A were significantly over-expressed in cancer populations compared to controls (p=0.009 and 0.011 respectively). A significant positive correlation between miRNA-126 and VEGF-A expression was also noted (p= 0.00009).

Real time PCR of extracted RNA from the cell lines has shown under-expression of miRNA-126 compared to normal cells while VEGF-A RNA and protein were over-expressed. The reduction of VEGF-A protein expression after transfection of miRNA-126 mimic into K1 and B-CPAP, confirms the regulatory role of miRNA-126 on VEGF-A expression in thyroid cancer cell lines.

These findings add weight to our previous understanding about the angiogenic role of miRNA-126 in cancer. These experiments provide information on the functional consequences of VEGF manipulation via miRNA on cancer. The data will provide primary information regarding the utility of over-expressing miRNA-126 in cancer management and future development of effective tumour-specific anti-angiogenic therapy.

Citation Format: Ali Salajegheh, Haleh Vosgha, Md. Atiqur Rahman, Vinod Gopalan, Robert Anthony Smith, Alfred King-Yin Lam. The modulatory role of miRNA 126 in thyroid cancer angiogenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 528. doi:10.1158/1538-7445.AM2014-528