Speaker: Dr. Ginés Morata
Centro de Biología Molecular
CSIC-UAM

Host

Jordi Casanova, IBMB/CSIC - IRB Barcelona

Friday, 19 March 2010, 12.00h Aula Fèlix Serratosa

Abstract

Mutant larvae for lethal giant larva (lgl) of Drosophila develop neoplastic tumours in imaginal discs. We have investigated the tumorigenic potential of lgl mutant cells by generating clones of various genetic combinations of lgl- cells surrounded by lgl+ cells. We find that lgl- cells are eliminated by cell competition, although not based on a difference in proliferation rate. However, lgl- cells may form tumours if they acquire constitutive activity for the Ras pathway (lgl- UAS-rasV12), which confers proliferation advantage through inhibition of the Hpo pathway. Yet, isolated lgl- UASrasV12 clones cannot form a tumour; it requires merging of many individual clones that generate a microenvironment protecting them from cell competition. We propose a two-step model of tumour formation: 1) the transformation of a normal into a tumour cell, defined by the capacity to grow indefinitely, 2) the acquisition, through inhibition of the Hpo pathway and cell merging, of the ability to escape cell competition.

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