4-Methylumbelliferone exerts anti-tumor effects in a dependent and independent manner to hyaluronan synthesis inhibition in human glioblastoma cells

Abstract

4-methylumbelliferone (4MU) is a non toxic coumarins derivative that shows anti-tumoral effects on several neoplasms. Despite being widely used as hyaluronan (HA) synthesis inhibitor, HA-independent effects have been recently reported. HA is the main glycosaminoglycan of extracellular matrix and it is strongly involved in tumor progression, favoring cell proliferation and migration, processes that are directly related with glioblastoma, the most common primary tumor of central nervous system. Given that current therapy for this type of cancer is ineffective and highly toxic, new drugs are required for glioblastoma treatment. Our hypothesis is that 4MU exerts anti-tumoral effects on glioblastoma as a consequence of dependent as well as independent mechanisms of hyaluronan synthesis. Therefore, the aim of this work was to evaluate the effect of 4MU, alone and in combination with hyaluronan, on cell migration and metabolic as well as metalloprotease (MMP) activity in LN229 and U251 human glioblastoma cell lines. Metabolic activity was evaluated by XTT assay, migration by wound healing assay, MMPs activity by zymography and cell death by FDA/PI using flow cytometry. 4MU reduced metabolic activity in a dose dependent manner in both cell lines (p<0.05), however this drug slightly modified the percentage of PI+ LN229 and U251 cells. Besides, 4MU decreased gap closure and MMP-2 activity in both cell lines (p<0.05). Furthermore, the addition of HA partially prevented the 4MU effect on migration and MMP-2 activity (p<0.05) without modifying metabolic activity respect to 4MU alone in LN229 and U251 cells. In conclusion, we demonstrate that 4MU anti-tumoral effects on glioblastoma cell migration and MMP-2 activity seem to be dependent of hyaluronan synthesis inhibition, while 4MU effect on metabolic activity showed signs of being independent of hyaluronan metabolism. Altogether, these results highlight the potential use of 4MU for glioblastoma therapy.