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

DIAZ MARIA ANGELES; LEDESMA MANUEL MARTIN; MARCHINI ; PIBUEL; POODTS; EVELSON; MORENO SILVIA; HAJOS; VALACCO PIA; LOMPARDIA SILVINA

Virtual

Congreso; LXV Reunión anual de la Sociedad Argentina de Investigación Clínica; 2020

Sociedad Argentina de Investigación Clínica

Despite continuous improvement in the treatment for acute myeloidleukemia (AML), new therapies are still needed to overcome re-sistance and reduce adverse effects. We previously proposed that4-methylumbelliferone (4MU), known as an inhibitor of hyaluronan(HA) synthesis, would be an interesting new drug for leukemia treat-ment. Previous results in our lab, showed that 4MU inhibited cellproliferation in a dose-dependent manner in human AML cell lines.Moreover, this drug was able to modulate mitochondrial status andROS production. However, it remains to assess whether the ob-served effects are explained by the inhibition of HA synthesis. Theaim of this work was to analyze if the anti-tumor activity of 4MUon U937 and THP-1 AML cells could be explained by HA synthesisinhibition. Results showed, that both AML cell lines were able to pro-duce significant quantities of AH (121.0 ± 0.6 ng/ml and 107.6 ± 0.5ng/ml, respectively) as assessed by ELISA. Surprisingly, 4MU wasable to partially inhibit HA synthesis in THP-1 cells (p< 0.001) butnot in U937 cells at the doses tested. The addition of HA failed toprevent the effects of 4MU on metabolic activity and cell proliferationin both cell lines, evaluated by XTT and 3H-T uptake, respectively.Moreover, 4MU+HA co-treatment failed to prevent the increase inthe mean of fluorescence of NAO by FC, as well as the increasein ROS production, as it was evaluated also by FC with DCF-DAand MitoSox staining, in both cell lines. These results suggestedthat there would be 4MU mechanisms independent of HA synthesisinhibition. To delve further into these mechanisms, we conducted aproteomic study in U937 cells after 4MU treatment by nano LC-MS/MS. Data analysis with free software RStudio resulted in 15 proteinsmodulated by 4MU (p80), mainly related with cellmetabolism signatures, but not directly linked to HA synthesis mech-anisms. This finding expand the knowledge of 4MU for its potentialuse in AML treatment.