Morphoproteomics Identifies SIRT1 and EZH2 Pathways as Commonalities in B-cell Acute Lymphoblastic Leukemia: Pathogenetic Implications and Opportunities for Therapeutic Intervention.

B-cell acute lymphoblastic leukemia (ALL) represents a malignant process in which bone marrow-derived lymphoblasts retain their undifferentiated state. Genetic testing has revealed either no identifiable cytogenetic and genomic abnormalities in such patients or a wide range of aberrations that may or may not contribute to the block in differentiation and the associated proliferation of the malignant lymphoblasts in cases of B-cell ALL. In this study, we applied morphoproteomics to a representative spectrum of cases of newly diagnosed B-cell ALL in order to identify pathways that are known to be associated with the maintenance of the undifferentiated state while promoting proliferation. Our results showed nuclear expression in a majority of the lymphoblasts from bone marrow clot preparations of each of the study cases for both silent mating type information regulation 2 homolog 1 (SIRT1), an NAD+ histone deacetylase and enhancer of Zeste homolog 2 (EZH2), a histone methyltransferase. These represent pathogenetic pathways capable of blocking differentiation and promoting proliferation of the B-cell ALL lymphoblasts. Data mining of the National Library of Medicine's MEDLINE Database and Ingenuity Pathway analysis revealed agents of relatively low toxicity-melatonin, metformin, curcumin and sulforaphane-that are capable of inhibiting directly or pharmacogenomically one or both of the SIRT1 and EZH2 pathways and should, in a combinatorial fashion, remove the block in differentiation and decrease the proliferation of the B-cell ALL lymphoblasts.