Biologic and clinical features of childhood gamma delta T-ALL: identification of STAG2/LMO2 γδ T-ALL as an extremely high risk leukemia in the very young.

PURPOSE: Gamma delta T-cell receptor-positive acute lymphoblastic leukemia (γδ T-ALL) is a high-risk but poorly characterized disease. METHODS: We studied clinical features of 200 pediatric γδ T-ALL, and compared the prognosis of 93 cases to 1,067 protocol-matched non-γδ T-ALL. Genomic features were defined by transcriptome and genome sequencing. Experimental modeling was used to examine the mechanistic impacts of genomic alterations. Therapeutic vulnerabilities were identified by high throughput drug screening of cell lines and xenografts. RESULTS: γδ T-ALL in children under three was extremely high-risk with 5-year event-free survival (33% v. 70% [age 3-<10] and 73% [age ≥10], P =9.5 x 10 -5 ) and 5-year overall survival (49% v. 78% [age 3-<10] and 81% [age ≥10], P =0.002), differences not observed in non-γδ T-ALL. γδ T-ALL in this age group was enriched for genomic alterations activating LMO2 activation and inactivating STAG2 inactivation ( STAG2/LMO2 ). Mechanistically, we show that inactivation of STAG2 profoundly perturbs chromatin organization by altering enhancer-promoter looping resulting in deregulation of gene expression associated with T-cell differentiation. Drug screening showed resistance to prednisolone, consistent with clinical slow treatment response, but identified a vulnerability in DNA repair pathways arising from STAG2 inactivation, which was efficaciously targeted by Poly(ADP-ribose) polymerase (PARP) inhibition, with synergism with HDAC inhibitors. Ex-vivo drug screening on PDX cells validated the efficacy of PARP inhibitors as well as other potential targets including nelarabine. CONCLUSION: γδ T-ALL in children under the age of three is extremely high-risk and enriched for STAG2/LMO2 ALL. STAG2 loss perturbs chromatin conformation and differentiation, and STAG2/LMO2 ALL is sensitive to PARP inhibition. These data provide a diagnostic and therapeutic framework for pediatric γδ T-ALL. SUPPORT: The authors are supported by the American and Lebanese Syrian Associated Charities of St Jude Children's Research Hospital, NCI grants R35 CA197695, P50 CA021765 (C.G.M.), the Henry Schueler 41&9 Foundation (C.G.M.), and a St. Baldrick's Foundation Robert J. Arceci Innovation Award (C.G.M.), Gabriella Miller Kids First X01HD100702 (D.T.T and C.G.M.) and R03CA256550 (D.T.T. and C.G.M.), F32 5F32CA254140 (L.M.), and a Garwood Postdoctoral Fellowship of the Hematological Malignancies Program of the St Jude Children's Research Hospital Comprehensive Cancer Center (S.K.). This project was supported by the National Cancer Institute of the National Institutes of Health under the following award numbers: U10CA180820, UG1CA189859, U24CA114766, U10CA180899, U10CA180866 and U24CA196173. DISCLAIMER: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The funding agencies were not directly involved in the design of the study, gathering, analysis and interpretation of the data, writing of the manuscript, or decision to submit the manuscript for publication.

The Beneficial Effects of Astaxanthin on Glucose Metabolism and Modified Low-Density Lipoprotein in Healthy Volunteers and Subjects with Prediabetes.

Astaxanthin (ASTX) is an antioxidant agent. Recently, its use has been focused on the prevention of diabetes and atherosclerosis. We examined the effects of astaxanthin supplementation for 12 weeks on glucose metabolism, glycemic control, insulin sensitivity, lipid profiles and anthropometric indices in healthy volunteers including subjects with prediabetes with a randomized, placebo-controlled trial. METHODS: We enrolled 53 subjects who met our inclusion criteria and administered them with 12 mg astaxanthin or a placebo once daily for 12 weeks. Subsequently, their HbA1c levels, lipid profiles and biochemical parameters were determined. The participants also underwent a 75 g oral glucose tolerance test (OGTT), vascular endothelial function test and measurement of the visceral fat area. RESULTS: After astaxanthin supplementation for 12 weeks, glucose levels after 120 min in a 75 g OGTT significantly decreased compared to those before supplementation. Furthermore, the levels of HbA1c (5.64 ± 0.33 vs. 5.57 ± 0.39%, p < 0.05), apo E (4.43 ± 1.29 vs. 4.13 ± 1.24 mg/dL, p < 0.05) and malondialdehyde-modified low-density lipoprotein (87.3 ± 28.6 vs. 76.3 ± 24.6 U/L, p < 0.05) were also reduced, whereas total cholesterol (TC), triglyceride (TG) and high-density lipoprotein-C (HDL-C) levels were unaltered. The Matuda index, which is one of the parameters of insulin resistance, was improved in the ASTX group compared to that before supplementation. CONCLUSIONS: our results suggest that ASTX may have preventive effects against diabetes and atherosclerosis and may be a novel complementary treatment option for the prevention of diabetes in healthy volunteers, including subjects with prediabetes, without adverse effects.

Preclinical evaluation of NUDT15-guided thiopurine therapy and its effects on toxicity and antileukemic efficacy.

Thiopurines (eg, 6-mercaptopurine [MP]) are highly efficacious antileukemic agents, but they are also associated with dose-limiting toxicities. Recent studies by us and others have identified inherited NUDT15 deficiency as a novel genetic cause of thiopurine toxicity, and there is a strong rationale for NUDT15-guided dose individualization to preemptively mitigate adverse effects of these drugs. Using CRISPR-Cas9 genome editing, we established a Nudt15-/- mouse model to evaluate the effectiveness of this strategy in vivo. Across MP dosages, Nudt15-/- mice experienced severe leukopenia, rapid weight loss, earlier death resulting from toxicity, and more bone marrow hypocellularity compared with wild-type mice. Nudt15-/- mice also showed excessive accumulation of a thiopurine active metabolite (ie, DNA-incorporated thioguanine nucleotides [DNA-TG]) in an MP dose-dependent fashion, as a plausible cause of increased toxicity. MP dose reduction effectively normalized systemic exposure to DNA-TG in Nudt15-/- mice and largely eliminated Nudt15 deficiency-mediated toxicity. In 95 children with acute lymphoblastic leukemia, MP dose adjustment also directly led to alteration in DNA-TG levels, the effects of which were proportional to the degree of NUDT15 deficiency. Using leukemia-bearing mice with concordant Nudt15 genotype in leukemia and host, we also confirmed that therapeutic efficacy was preserved in Nudt15-/- mice receiving a reduced MP dose compared with Nudt15+/+ counterparts exposed to a standard dose. In conclusion, we demonstrated that NUDT15 genotype-guided MP dose individualization can preemptively mitigate toxicity without compromising therapeutic efficacy.

Notch2 activation ameliorates nephrosis.

Activation of Notch1 and Notch2 has been recently implicated in human glomerular diseases. Here we show that Notch2 prevents podocyte loss and nephrosis. Administration of a Notch2 agonistic monoclonal antibody ameliorates proteinuria and glomerulosclerosis in a mouse model of nephrosis and focal segmental glomerulosclerosis. In vitro, the specific knockdown of Notch2 increases apoptosis in damaged podocytes, while Notch2 agonistic antibodies enhance activation of Akt and protect damaged podocytes from apoptosis. Treatment with triciribine, an inhibitor of Akt pathway, abolishes the protective effect of the Notch2 agonistic antibody. We find a positive linear correlation between the number of podocytes expressing activated Notch2 and the number of residual podocytes in human nephrotic specimens. Hence, specific activation of Notch2 rescues damaged podocytes and activating Notch2 may represent a novel clinical strategy for the amelioration of nephrosis and glomerulosclerosis.