Expression of mi̇krornas regulating TRPM2 ion channels in glioblastoma multiforme tissues and electrophysiological characterization of TRPM2 channels in glioblastoma cell lines

EXPRESSION OF MİKRORNAS REGULATING TRPM2 ION CHANNELS IN GLIOBLASTOMA MULTIFORME TISSUES AND ELECTROPHYSIOLOGICAL CHARACTERIZATION OF TRPM2 CHANNELS IN GLIOBLASTOMA CELL LINES Nurcan ŞAHİN DEMİR Master of Science Thesis, Department of Physiology Supervisor: Prof. Dr. Ramazan BAL June 2014, 46 pages World Health Organization (WHO) divided gliomas into four grades depending on their aggressiveness; grade I, grade II, grade III and grade IV. According to this grading, grade I is the most benign and grade IV is the most malignant tumors. It was found that TRP ion channels are responsible for several physiological phenomenons such as ionic equilibrium and sensitivity to different types of stimuli in many cell groups and tissues. Many of TRP ion channels have nonselective cation channels, whereas some of them are selective for Ca2+ ions, some are permeable to Mg2+ ions. miRNAs are small RNA molecules with 18-24 nucleotides. miRNAs have important roles in cell proliferation, cell differentiation and cell death. It has been suggested that some miRNAs are acting as tumor suppressors, whereas others have oncogenic properties. The aim of the study is to analyze of expression of miR4755-3p and miR-423-5p, which target TRPM2 in paraffin tissue samples taken from different glioblastoma patients with different grades by using by qRT-PCR. Presence of TRPM2 channels was demonstrated by using patch-clamp technique in glioblastome cell line U87. The expression levels of miR-4755-3p and miR423-5p of grade IV patients were assumed as 1 because of absence of normal brain tissue.The expression levels of miR-4755-3p ve miR423-5p of patients with grade I, II and III were compared with grade IV. It was found that the expression levels of miR-4755-3p and miR423-5p were decreased in grade II. Whole cell current was partially blocked by N-(p-amylcinnamoyl) anthranilic acid (AAC) (50µM). The ACA-sensitive current was referred as TRPM2 current. Key words: Glioblastoma, Cancer, miRNA, Patch-Clamp, and TRPM2