RHOA KNOCKDOWN AFFECTS P53 SUBCELLULAR LOCALIZATION IN LEUKEMIA CELLS IRRADIATED WITH UVC

Abstract

Introduction and aims: Acute myeloid leukemia (AML) is a severe hematological malignancy with low rates of survival. Mutations in the tumor suppressor gene TP53 are present in around 10% of AML cases and are associated with a worse prognosis. Evidence suggests that the Rho GTPase proteins RhoA and RhoC are involved in the regulation of p53 activity. In this study, we aimed to investigate the relation between RhoA and RhoC expression and p53 expression and subcellular localization in leukemia cells. Methods: OCI-AML3 cell line (wild type TP53) was transduced with lentiviral particles containing specific shRNA for the silencing of RhoA (shRhoA) or RhoC (shRhoC) or non-specific shRNA (shCTRL). Cells were irradiated with UVC and nucleus (DAPI) and p53 were identified by confocal microscopy. Results: Non irradiated OCI-AML3 cells presented a mild p53 fluorescence intensity since they were not exposed to any exogenous stress. However, shRhoA and shRhoC cells presented a slight increase in p53 in the cytoplasm and nucleus. As expected, UVC irradiation increased the p53 fluorescence. Notably, shRhoA cells irradiated with UVC showed an even more pronounced increase in p53 fluorescence (both in the cytoplasm and nucleus) compared to shCTRL cells under the same conditions. Conclusions: Our results suggest that p53 expression and localization may be at least partially controlled by Rho signaling in leukemia cells. Funding: FAPESP.