Evaluation of the effects of 4-methylumbeliferone on glioblastoma cell lines

DÍAZ M.; LOMBARDO T.; PAPADEMETRIO D. L.; PIBUEL M.; MIHALEZ C.Y.; ALVAREZ E. M. C.; LOMPARDÍA S. L.; COSTANTINO S.; LEVERMANN M.; HAJOS S. E.

Cleveland

Congreso; Hyaluronan Meeting 2017; 2017

ISHAS

Glioblastoma (GBM), the most common type of primary brain tumor in adults, is a very aggressive and locally invasive tumor. Despite advances in therapy the survival of patients still remains very low.4-methylumbeliferone (4MU) is a coumarin derivative that has been approved in Europe and Asia to treat biliary spasms. During the last years, it has been proposed as a potential new drug for the treatment of solid tumors because its effects on cell proliferation, migration and invasion due to its capacity to inhibit hyaluronic acid (HA) synthesis, but yet little is known about its effect on brain tumors. Doxorubicin (DOX) has been shown to arrest cell growth and induce apoptosis in malignant glioma cell lines. However, it still has no clinical application because of its serious side effects. In view of this, we hypothesized that 4MU alone or in combination with DOX could be promising new treatments for GBM. Therefore the aim of this work was to evaluate the effects of 4MU, DOX and their combination (4MU+DOX) on the human GBM cell line U251 and the murine GBM cell line GL26 and to assay if these effects could be reverse by the combination with HA. Cell viability was evaluated by XTT assay, apoptosis was assessed by fluorescence microscopy using AO/EB and DAPI stains and the modulation of metaloproteases (MMPs) activities were studied by gelatin zimography. Results showed that 4MU as well as DOX abrogate both cells growth in a dose-dependent manner and increased the percentage of cells with nuclear fragmentation at high doses. In the same way, both drugs increased the percentage of AO+ (early apoptotis) and EB+ cells with nuclear fragmentation which is consistent with an augment of apoptotic cells. AH couldn´t reverse 4MU effects. (4MU+DOX) didn?t show a higher effect than each drug alone, but lower doses should be tested. Recently, it has been shown that 4MU could modulate MMP activities, so we decided to evaluate if this happened on both cells lines. Results showed that 4MU could down-regulate MMP activity and this modulation couldn´t be reverse by HA. In view of these we can conclude that 4MU abrogates cell viability mainly by the induction of apoptosis. 4MU also down-regulates MMP activity and that would be a beneficial result since glioblastoma is an aggressive and locally invasive tumor.These findings highlight 4MU as a potential new drug for GBM treatment.