TUMOR-SUPPRESSIVE FUNCTIONS OF 4-METHYLUMBELLIFERONE ON HUMAN AML CELLS: STUDY OF HYALURONAN-SYNTHESIS-INHIBITION INDEPENDENT MECHANISMS.

MARTIN LEDESMA; DANIELA POODTS; SILVIA HAJOS; TIMOTEO MARCHINI; PABLO EVELSON; MARIA PIA VALACCO; MARIANGELES DIAZ; MATIAS PIBUEL; SILVIA MORENO; SILVINA LOMPARDIA

Congreso; Reunion Anual de Sociedades de Biocencia 2020; 2020

SAIC-SAFIS-SAI

Despite continuous improvement in the treatment for acute myeloid leukemia (AML), new therapies are still needed to overcome resistance and reduce adverse effects. We previously proposed that 4-methylumbelliferone (4MU), known as an inhibitor of hyaluronan (HA) synthesis, would be an interesting new drug for leukemia treatment. Previous results in our lab, showed that 4MU inhibited cell proliferation in a dose-dependent manner in human AML cell lines. Moreover, this drug was able to modulate mitochondrial status and ROS production. However, it remains to assess whether the observed effects are explained by the inhibition of HA synthesis. The aim of this work was to analyze if the anti-tumor activity of 4MU on U937 and THP-1 AML cells could be explained by HA synthesis inhibition. Results showed, that both AML cell lines were able to produce significant quantities of AH (121.0 ± 0.6 ng/ml and 107.6 ± 0.5 ng/ml, respectively) as assessed by ELISA. Surprisingly, 4MU was able to partially inhibit HA synthesis in THP-1 cells (p< 0.001) but not in U937 cells at the doses tested. The addition of HA failed to prevent the effects of 4MU on metabolic activity and cell proliferation in both cell lines, evaluated by XTT and 3 H-T uptake, respectively. Moreover, 4MU+HA co-treatment failed to prevent the increase in the mean of fluorescence of NAO by FC, as well as the increase in ROS production, as it was evaluated also by FC with DCF-DA and MitoSox staining, in both cell lines. These results suggested that there would be 4MU mechanisms independent of HA synthesis inhibition. To delve further into these mechanisms, we conducted a proteomic study in U937 cells after 4MU treatment by nano LC-MS/ MS. Data analysis with free software RStudio resulted in 15 proteins modulated by 4MU (p80), mainly related with cell metabolism signatures, but not directly linked to HA synthesis mechanisms. This finding expand the knowledge of 4MU for its potential use in AML treatment