Abstract 2047: Expression of microRNAs in squamous cell carcinoma of human head and neck (HNSCC) and the esophagus (ESCC) and their regulation by hepatocyte growth factor
Authors: Kimura Sotai , Naganuma Seiji , Susuki Dai , Kitamura Naomi , Itoh Hiroshi 
Published: February 2011

Abstract
Introduction: MicroRNAs (miRNAs) are non-coding small RNAs that regulate cell proliferation and various cellular functions by interfering the translation of target mRNAs. Altered expression of miRNA is known to induce various human malignancies. Hepatoceyte growth factor (HGF) is a multifunctional growth factor that acts as mitogen, motogen, and/or morphogen in a variety of cells. MET, a specific receptor tyrosine kinase for HGF, is up-regulated in various tumors including squamous cell carcinoma of human head and neck (HNSCC) and the esophagus (ESCC), but how HGF affect the downstream gene expression have not yet been elucidated in detail. In this study, we examined the expression of miRNAs and their regulation by HGF in HNSCC and ESCC. Methods: Nine HNSCC, 8 ESCC and 2 normal squamous cell lines were used for cell culture. Total RNAs were extracted and used for microarray and following quantitative reverse transcription real-time PCR (qRT-PCR). Validation study was performed by qRT-PCR using total RNAs extracted from formalin-fixed paraffin-embedded human cancer tissues and paired normal tissues by laser-captured microdissection. For miRNA regulation study, HSC3 cells (HNSCC cell line) expressing MET was cultured with or without HGF stimulation, and their total RNAs were extracted and analyzed by miRNA microarray and following qRT-PCR. The expression of target mRNAs for miRNAs altered by HGF stimulation was also examined by qRT-PCR. Results: In HNSCC, ESCC, and normal squamous cell lines, miR-205 showed the highest expression in miRNA microarray analysis. High expression of miR-205 was observed in not only HNSCC and ESCC but also other organs’ SCC and adjacent normal squamous epithelia by qRT-PCR in validation study, although less expression was detected in cells and tissues other than squamous epithelia. MiR-21, which is an oncogenic miRNA in various malignancies, was also up-regulated in HNSCC and ESCC compared to paired normal squamous epithelia. By HGF stimulation, miR-200c and miR-27b were significantly down-regulated in HSC3 cells. Interestingly, the expression of ZEB1, a target mRNA for miR-200c, was up-regulated and E-cadherin, downstream molecule of ZEB1, was down-regulated in these cells after HGF stimulation. Conclusion: Our present results suggest that miRNA expression pattern and target mRNAs of HNSCC and ESCC are different from those of other organ's malignancies. MiR-205 might be a specific marker miRNA of both normal and malignant squamous epithelia, while miR-21 might be a putative oncogenic miRNA in HNSCC and ESCC. In addition, several miRNAs including miR-200c and miR-27b down-regulated by HGF stimulation might play an important role for epithelial-mesenchymal transition (EMT) followed by enhanced invasive characteristics of HNSCC and ESCC, through up-regulation of ZEB1 followed by down-regulation of E-cadherin.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2047.