J Pharm Pharmacogn Res 2(Suppl. 1): S3, 2014
Special supplement with the abstract book of LATINFARMA 2013
CO 003: PHARMACOLOGIC INTERVENTION OF CASEIN KINASE 2 (CK2)-MEDIATED PRO-SURVIVAL AND PROLIFERATIVE SIGNALING ON T-CELL ACUTE LYMPHOBLASTIC LEUKEMIA (T-ALL)
Perera Y1, Melao A2, Miranda J3, Perea SE1, Barata JT.2
Introduction: Despite sustained advances in the treatment of T-cell Acute Lymphoblastic Leukemia (T-ALL) mortality rates are still unacceptable high, stressing the necessity to develop new therapeutic compounds. The role of CK2 on T-ALL biology has been recently addressed by experimental and clinical data. Such findings uncover the relevance of CK2-mediated phosphorylation on PTEN inactivation, leading to an aberrant PI3K/Akt signaling and increasing T-ALL survival and proliferation. Importantly, emerging evidences also connect CK2 activity with IL-7-mediated signaling, a cytokine with leukemia supportive effect. Here, we analyzed the impact of CIGB-300 peptide, a molecule designed to block CK2-mediated phosphorylation by direct binding to conserved phosphoaceptor domain on its substrates, on T-ALL biology.
Methods: CIGB-300´s antiproliferative effect was assessed on T-ALL cell lines representing common genetic lesions and differentiation stages (n=8) using Alamar blue and H3-thymidine assays. Cytotoxicity and cell cycle distribution were determined by FACS using AnnexinV7AAD and PI staining, respectively. IL7-mediated activation on primary-like TAIL7 (IL7-dependend) and HPB-ALL (IL7-responsible) cells was determined by FSC vs. SSC analysis. CIGB-300´s cytotoxic effects was verified in co-culture experiments using transfected murine stromal cells (OP9DL1) and primary leukemia cells from patients (n=6). Signaling experiments were performed by western blot.
Results: CIGB-300´s exerted a dose-response antiproliferative effect on T-ALL cells (IC50 mean= 24 µM) which can be explained by direct induction of cell death. Such effect overcomes IL7-mediated activation and viability boost, both in cell lines and patient samples, while prevents stromal support in vitro. Signaling experiments point to two described CK2 substrates as potential targets for CIGB-300 on T-ALL (i.e. NPM/B23 and P27) while in the context of IL7-stimulation putative new unexpected target(s) emerge upstream in JAK-STAT signaling axis (i.e. JAK1).
Conclusion: Our data support the suitability of anti-CK2 pharmacologic interventions to impair T-ALL survival and proliferation even in the context of aberrant IL7-IL7R signaling.