Cyclosporine Broadens the Therapeutic Potential of Lenalidomide in Myeloid Malignancies

Recent advances in acid sensing by G protein coupled receptors

Changes in extracellular proton concentrations occur in a variety of tissues over a range of timescales under physiological conditions and also accompany virtually all pathologies, notably cancers, stroke, inflammation and trauma. Proton-activated, G protein coupled receptors are already partially active at physiological extracellular proton concentrations and their activity increases with rising proton concentrations. Their ability to monitor and report changes in extracellular proton concentrations and hence extracellular pH appears to be involved in a variety of processes, and it is likely to mirror and in some cases promote disease progression. Unsurprisingly, therefore, these pH-sensing receptors (pHR) receive increasing attention from researchers working in an expanding range of research areas, from cellular neurophysiology to systemic inflammatory processes. This review is looking at progress made in the field of pHRs over the past few years and also highlights outstanding issues.

Mutated IKZF1 is an independent marker of adverse risk in acute myeloid leukemia

Genetic lesions of IKZF1 are frequent events and well-established markers of adverse risk in acute lymphoblastic leukemia. However, their function in the pathophysiology and impact on patient outcome in acute myeloid leukemia (AML) remains elusive. In a multicenter cohort of 1606 newly diagnosed and intensively treated adult AML patients, we found IKZF1 alterations in 45 cases with a mutational hotspot at N159S. AML with mutated IKZF1 was associated with alterations in RUNX1, GATA2, KRAS, KIT, SF3B1, and ETV6, while alterations of NPM1, TET2, FLT3-ITD, and normal karyotypes were less frequent. The clinical phenotype of IKZF1-mutated AML was dominated by anemia and thrombocytopenia. In both univariable and multivariable analyses adjusting for age, de novo and secondary AML, and ELN2022 risk categories, we found mutated IKZF1 to be an independent marker of adverse risk regarding complete remission rate, event-free, relapse-free, and overall survival. The deleterious effects of mutated IKZF1 also prevailed in patients who underwent allogeneic hematopoietic stem cell transplantation (n = 519) in both univariable and multivariable models. These dismal outcomes are only partially explained by the hotspot mutation N159S. Our findings suggest a role for IKZF1 mutation status in AML risk modeling.

Ikaros Proteins in Tumor: Current Perspectives and New Developments

Ikaros is a zinc finger transcription factor (TF) of the Krüppel family member, which significantly regulates normal lymphopoiesis and tumorigenesis. Ikaros can directly initiate or suppress tumor suppressors or oncogenes, consequently regulating the survival and proliferation of cancer cells. Over recent decades, a series of studies have been devoted to exploring and clarifying the relationship between Ikaros and associated tumors. Therapeutic strategies targeting Ikaros have shown promising therapeutic effects in both pre-clinical and clinical trials. Nevertheless, the increasingly prominent problem of drug resistance targeted to Ikaros and its analog is gradually appearing in our field of vision. This article reviews the role of Ikaros in tumorigenesis, the mechanism of drug resistance, the progress of targeting Ikaros in both pre-clinical and clinical trials, and the potential use of associated therapy in cancer therapy.

Novel Molecular Mechanism of Lenalidomide in Myeloid Malignancies Independent of Deletion of Chromosome 5q

Lenalidomide as well as other immunomodulatory drugs (IMiDs) have achieved clinical efficacies in certain sub-types of hematologic malignancies, such as multiple myeloma, lower-risk myelodysplastic syndromes (MDS) with a single deletion of chromosome 5q (del(5q)) and others. Despite superior clinical response to lenalidomide in hematologic malignancies, relapse and resistance remains a problem in IMiD-based therapy. The last ten years have witnessed the discovery of novel molecular mechanism of IMiD-based anti-tumor therapy. IMiDs bind human cereblon (CRBN), the substrate receptor of the CRL4 E3 ubiquitin ligase complex. Binding of CRBN with IMiDs leads to degradation of the Ikaros family zinc finger proteins 1 and 3 (IKZF1 and IKZF3) and casein kinase 1 alpha. We have found that lenalidomide-mediated degradation of IKZF1 leads to activation of the G protein-coupled receptor 68 (GPR68)/calcium/calpain pro-apoptotic pathway and inhibition of the regulator of calcineurin 1 (RCAN1)/calcineurin pro-survival pathway in MDS and acute myeloid leukemia (AML). Calcineurin inhibitor Cyclosporin-A potentiates the anti-leukemia activity of lenalidomide in MDS/AML with or without del(5q). These findings broaden the therapeutic potential of IMiDs. This review summarizes novel molecular mechanism of lenalidomide in myeloid malignancies, especially without del(5q), in the hope to highlight novel therapeutic targets.

5q Deletion Myelodysplastic Syndrome in a Young Male Patient

Myelodysplastic syndromes (MDS) are a diverse group of hematopoietic stem cell malignancies with various phenotypic variability that are categorized by abnormal differentiation of one or multiple cell lines of the bone marrow. A large part of the phenotypic heterogeneity is in part due to the wide set of genetic defects related to MDS. Though clinically, MDS is centered on diagnostic measures that do not incorporate molecular genetic data, an isolated deletion of the long arm of chromosome 5 (del(5q)) is the only subset of MDS to be identified by genetic defects. This distinctive phenotype is termed 5q-syndrome. We report a case of a 25-year-old with a past medical history of polydactyly, severe anemia, and thrombocytopenia who presented to the emergency department with a chief complaint of weakness and fatigue. Bone marrow biopsy showed myeloid neoplasm with complex genetic abnormalities, nearly 100% hyperplastic marrow with marked trilineage dysplasia, relative myeloid hyperplasia with increased abnormal eosinophilic precursors, erythroid left shift, and atypical megakaryocytes. Fluorescence in situ hybridization (FISH) panel showed deletion of 5q-. Herein, we address the clinical course and morphological characteristics as well as possible therapeutic options for 5q syndrome.