Influence of ROCK kinases on proliferation and migratory ability of medulloblastomas with activation of the SHH pathway

Abstract

Medulloblastoma (MB) is the most common pediatric tumor of the central nervous system. It is an embryonic neuroepithelial tumor arising from the cerebellum and occurs in 20% of children diagnosed with malignant tumor in the CNS. Clinical prognosis follows three criteria: age of the patient, the extent of surgical resection and the spread of disease. Treatment of medulloblastoma consists of maximum surgical resection followed by radiation and chemotherapy. Currently there are four distinct molecular variants of medulloblastoma (Wnt, Shh, Group 3 and Group 4) with different genetic, demographic and prognostic profiles. Each variant subgroup presents regulation to proteins signaling pathways responsible for embryonic development of the cerebellum, such as Shh, which controls cell proliferation. This genetic deregulation results in tumor emergence and therefore its study is essential for the development of new treatment and chemical regimes. One of the therapeutic targets aimed at producing new drugs is ROCK, a kinase effector of RhoA GTPases, responsible for the control of cell migration. Recent studies have presented evidence that RhoA / ROCK signaling participates in the Shh pathway. Indeed, a link between the two pathways offers a new vision of how Shh can perform its multiple cellular functions. This study aims to study the expression levels of ROCK1 and ROCK2 in samples of affected patients with MB and to verify the effects of the inhibition of these kinases in the Shh signaling pathway in medulloblastoma cell lines with different expressions of proteins involved in thid pathway. Proliferation assays clonogenic capacity, migration, and apoptosis after treatment with a specific inhibitor will be carried out, as well as evaluation of the expression of target genes via Shh. If overexpression of ROCK1 is confirmed in tumor samples, but not in cell lines, we will induce ROCK kinase expression with a lentiviral vector in order to study its interaction with members of the SHH pathway.