Characterization of the pattern of melatonin synthesis by glioma cell lines with different grades of aggressiveness

• Grant number: 12/23915-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2013
• End date: February 28, 2014
• Field of knowledge: Biological Sciences - Pharmacology - General Pharmacology
• Principal Investigator: Regina Pekelmann Markus
• Grantee: Gabriela Sarti Kinker
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Gliomas are recurrent primary brain tumors classified according to their proliferation rate and invasiveness. A preliminary study of gene expression in material obtained from patients with glioma showed a significant negative correlation between the grade of invasiveness and the expression of the gene that encodes the enzyme responsible for converting N-acetylserotonin (NAS) in melatonin (MEL). Accordingly, we raised two hypotheses: 1) the grade of invasiveness is inversely proportional to the amount of melatonin synthesized by the glioma; 2) processes that can inhibit the production of MEL by the glioma, as stimulation with pathogen-associated molecular patterns (PAMPs) or pro-inflammatory cytokines, will potentiate the invasiveness of the tumor. In this project we are going to use 3 models of human glioma with different grades of aggressiveness: the more invasiveness ones (U87MG and T98G) are astrocytomas and the less invasiveness (HOG) is an oligodendroglioma. We are going to test the first hypothesis by analyzing the expression of mRNA from enzymes of the MEL biosynthetic pathway (arylalkylamine N-acetyltransferases, AA-NAT; N-acetylserotonin O-methyltransferase, ASMT) and the content of MEL synthesized by cells incubated with NAS. To test the second hypothesis the same protocol is going to be used in the presence of lipopolysaccharides of Gram-negative bacteria (LPS) and tumor necrosis factor (TNF), in a way that mimics an inflammatory response. This project is basic for understanding the role of endogenous melatonin in glioma progression, creating new perspectives for understanding the biology of tumors,s and proposing therapies or using the molecule as a marker of aggressiveness.(AU)