MB-65: IDENTIFICATION OF PROTEINS ASSOCIATED WITH MEDULLOBLASTOMA DISPERSAL USING AN ‘ALL HUMAN’ IN VITRO MODEL

Leptomeningeal dissemination of medulloblastoma (MB) is associated with poor prognosis. Leptomeningeal dissemination is complex and most likely involves extracellular matrix molecules (ECM) and ECM signalling. We conducted a study to identify differentially expressed ECM molecules using a human ‘leptomeningeal’ cell-MB model (BMEN1 and CHLA-01). BMEN1 is a low-grade meningioma that has been genetically modified and has been used by others as a model for MB dispersal. The CHLA-01-Med (primary) and CHLA-01R-Med (recurrent metastasis) cell lines are from the same patient. BMEN1 cells were treated with conditioned media from either CHLA-01 or CHLA-01R for 48 hrs then protein and RNA was extracted to use with an ECM focused PCR array. Twenty of 84 genes were found to be upregulated, 6 ECM related genes were upregulated greater than 3-fold. Initial data analyses examining the 20 upregulated genes revealed several interesting findings. For example, MMP-9, MMP-15, COL15A1, VCAN and THBS1 were found to be over expressed in Group 3 or Group 4. Interestingly, MMP-15 was highest in metastatic medulloblastoma M₂ and M₃. MMP-15 protein expression was then analysed using Western blot and flow cytometry. To gain further understanding of cell motility, BMEN1 cells were plated, allowed to attach and fluorescent labelled MB cell lines were added. The MB cell line CHLA-01R was more motile on the BMEN1 cells than the CHLA-01 MB cells (P < 0.0001) as seen in cell tracking experiments. These findings support further investigation into the role of specific ECM molecules on MB dispersal.