Enhanced Expression of Glycolytic Enzymes and Succinate Dehydrogenase Complex Flavoprotein Subunit A by Mesothelin Promotes Glycolysis and Mitochondrial Respiration in Myeloblasts of Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is an aggressive malignancy characterized by rapid growth and uncontrolled proliferation of undifferentiated myeloid cells. Metabolic reprogramming is commonly observed in the bone marrow of AML patients, as leukemia cells require increased ATP supply to support disease progression. In this study, we examined the potential role of mesothelin as a metabolic modulator in myeloid cells in AML. Mesothelin is a well-known marker of solid tumors that promotes cancer cell proliferation and survival. We initially analyzed alterations in mesothelin expression in the myeloblast subpopulations, defined as SSC-Alow/CD45dim, obtained from the bone marrow of AML patients using flow cytometry. Our results showed overexpression of mesothelin in 34.8% of AML patients. Subsequently, metabolic changes in leukemia cells were evaluated by comparing the oxygen consumption rates (OCR) of bone marrow samples derived from adult AML patients. Notably, a higher OCR was observed in the mesothelin-positive compared to the mesothelin-low and non-expressing groups. Treatment with recombinant human mesothelin protein enhanced OCR and increased the mRNA expression of glycolytic enzymes and mitochondrial complex II in KG1α AML cells. Notably, siRNA targeting mesothelin in KG1α cells led to the reduction of glycolysis-related gene expression but had no effect on the mitochondrial complex gene. The collective results demonstrate that mesothelin induces metabolic changes in leukemia cells, facilitating the acquisition of a rapid supply of ATP for proliferation in AML. Therefore, the targeting of mesothelin presents a potentially promising approach to mitigating the progression of AML through the inhibition of glycolysis and mitochondrial respiration in myeloid cells.

Autoimmune Limbic Encephalitis in Patients with Hematologic Malignancies after Haploidentical Hematopoietic Stem Cell Transplantation with Post-Transplant Cyclophosphamide.

Autoimmune limbic encephalitis (LE) is a rare, but devastating complication of allogeneic hematopoietic stem cell transplantation (HSCT). There is currently limited evidence describing the risk factors, laboratory features, and underlying mechanisms of this neurologic adverse event. We retrospectively reviewed available clinical, imaging, and laboratory data from adult patients with hematological malignancies who underwent haploidentical HSCT with post-transplant cyclophosphamide (PTCy) at Chungnam National University Hospital from June 2016 to May 2020. Patients who developed LE were compared to those who did not based on clinical assessment, serum inflammatory biomarkers, and reconstitution of various T cell populations. Of 35 patients, 4 developed LE. There were no differences in patient demographics, donor demographics, or treatment conditions between patients that did and did not develop LE. Overall, patients with LE had worse clinical outcomes and overall survival than those without. In addition, they tended to have higher markers of systemic inflammation in the early post-transplant period, including fever, C-reactive protein (CRP), and cytokines. Remarkably, baseline interleukin-6 levels before HSCT were found to be higher in patients who developed LE than those who did not. In addition, analysis of T cell subsets showed impaired expansion of CD25+FOXP3+ regulatory T (Treg) cells in LE compared to non-LE patients despite appropriate reconstitution of the total CD4+ T cell population. Patients that developed LE within the first 30 days of HSCT were likely to have high serum IL-6 among other inflammatory cytokines coupled with suppression of regulatory T cell differentiation. Further work is needed on the mechanisms underlying impaired Treg expansion following HSCT and potential therapies.

Impact of pre-transplant use of antibiotics on the graft-versus-host disease in adult patients with hematological malignancies.

OBJECTIVES: Changes in fecal microbiota affect the incidence and extent of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). Most patients with hematological malignancies receive antibiotics for the treatment of febrile neutropenia prior to allogeneic HSCT, and pre-transplant use of antibiotics may influence the fecal microbiota and GVHD. METHODS: We retrospectively analysed consecutive adult patients with hematological malignancies who received allogeneic HSCT at Chungnam National University Hospital between 2007 and 2018. Pre-transplant use of antibiotics was defined as the use of antibiotics before conditioning chemotherapy. RESULTS: This study included 131 patients with a median age of 46 (range, 18-71) years: 76 (58%) patients were AML, 28 (21.4%) with ALL, 23 (17.6%) with MDS, and 4 (3.1%) with CML. All patients received calcineurin inhibitors with short-course methotrexate for GVHD prophylaxis. A total of 31 (23.7%) patients received anti-thymocyte globulin. All patients received antibiotics prior to HSCT: 70 (53.4%) patients received glycopeptide, 114 (87.0%) received cefepime, 87 (66.4%) received piperacillin/tazobactam, and 51 (38.9%) received carbapenem. Patients who received glycopeptide had more frequently extensive chronic GVHD (cGVHD) than those who did not (51.1% vs. 28.1% at 5 years) and had more frequently cGVHD of the lung (34.8% vs. 15.8% at 5 years). Pre-transplant use of glycopeptide did not affect the overall survival (OS) or GVHD- and relapse-free survival (GRFS) (median OS; 49 months in glycopeptide group vs. not reached in non-glycopeptide group, p=0.475; median GRFS; 9 months in glycopeptide group vs. 16 months in non-glycopeptide group, p=0.092). CONCLUSION: Pre-transplant use of glycopeptide tends to increase the incidence of extensive cGVHD.