CD52 is a novel target for the treatment of FLT3-ITD-mutated myeloid leukemia.

Internal tandem duplication (ITD) of FMS-like tyrosine kinase 3 (FLT3) confers poor prognosis and is found in approximately 25% of cases of acute myeloid leukemia (AML). Although FLT3 inhibitors have shown clinical benefit in patients with AML harboring FLT3-ITD, the therapeutic effect is limited. Here, to explore alternative therapeutics, we established a cellular model of monoallelic FLT3ITD/WT cells using the CRISPR-Cas9 system in a human myeloid leukemia cell line, K562. cDNA microarray analysis revealed elevated CD52 expression in K562-FLT3ITD/WT cells compared to K562-FLT3WT/WT cells, an observation that was further confirmed by quantitative real-time-PCR and flow cytometric analyses. The elevated expression of CD52 in K562-FLT3ITD/WT cells was decreased in wild-type FLT3 (FLT3-WT) knock-in K562-FLT3ITD/WT cells. In K562-FLT3ITD/WT cells, a STAT5 inhibitor, pimozide, downregulated CD52 protein expression while an AKT inhibitor, afuresertib, did not affect CD52 expression. Notably, an anti-CD52 antibody, alemtuzumab, induced significant antibody-dependent cell-mediated cytotoxicity (ADCC) in K562-FLT3ITD/WT cells compared to K562-FLT3WT/WT cells. Furthermore, alemtuzumab significantly suppressed the xenograft tumor growth of K562-FLT3ITD/WT cells in severe combined immunodeficiency (SCID) mice. Taken together, our data suggested that genetically modified FLT3-ITD knock-in human myeloid leukemia K562 cells upregulated CD52 expression via activation of STAT5, and alemtuzumab showed an antitumor effect via induction of ADCC in K562-FLT3ITD/WT cells. Our findings may allow establishment of a new therapeutic option, alemtuzumab, to treat leukemia with the FLT3-ITD mutation.

Pretreatment Immature Platelet Fraction as a Surrogate of Reticulated Platelets Predicts the Response to Corticosteroids in Adults with Immune Thrombocytopenia.

OBJECTIVES: Reticulated platelets circulating in the blood reflect megakaryopoietic activity and platelet turnover and can be automatically and low-invasively measured as the immature platelet fraction (IPF) using a Sysmex XN hematocytometer. The present study retrospectively investigated whether or not the IPF can predict the treatment response to corticosteroids in adult patients with primary immune thrombocytopenia (ITP). METHODS: Forty-six patients who had been newly diagnosed with primary treatment-naïve ITP and started treatment with corticosteroids were analyzed. RESULTS: Among the 46 primary ITP patients, 33 (72%) responded to the treatment and 13 (28%) did not. The percentage of IPF (IPF%) among the nonresponders was significantly lower than that of the responders (6.6 vs. 16.0%; p < 0.001). In the receiver operating characteristics analysis, the optimum IPF% cut-off value for predicting the treatment response was 12%, with a specificity of 85% and a sensitivity of 76%. CONCLUSIONS: Our findings thus suggest that measuring the IPF% as a surrogate of reticulated platelets is useful to identify patients likely to respond to corticosteroids.

Immunomodulatory and Metabolic Changes after Gnetin-C Supplementation in Humans.

Gnetin-C is a naturally occurring stilbene derived from the seeds of Gnetum gnemon L., an edible plant native to Southeast Asia that is called melinjo. Although the biological properties and safety of G. gnemon extract, which contains nearly 3% Gnetin-C, have been confirmed in various human studies, whether or not pure Gnetin-C is safe for humans is unclear at present. We conducted a randomized, double-blind, placebo-controlled trial. Healthy subjects were randomly divided into two groups. The interventional group (n = 6) was given Gnetin-C, and the control group (n = 6) was provided a placebo, for 14 days. Lipid profiles, biomarkers of oxidative stress and circulating blood cells were assessed before and after the intervention. All subjects completed the study, with no side effects reported across the study duration. Gnetin-C supplementation demonstrated a statistically significant increase in the absolute number of circulating natural killer (NK) cells expressing the activating receptors NKG2D and NKp46. NK cells derived from subjects who received Gnetin-C for two weeks showed higher cytotoxicity against K562 target cells than those before receiving Gnetin-C. In addition, Gnetin-C also resulted in a significant decrease in the absolute neutrophil count in the blood compared with the placebo. Furthermore, Gnetin-C significantly reduced the levels of uric acid, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total adiponectin, and high-molecular-weight adiponectin. These data indicate that Gnetin-C has biological effects of enhancing the NK activity on circulating human immune cells. The immunomodulatory effects are consistent with a putative improvement in cancer immunosurveillance via the upregulation of the NKG2D receptor. The study was registered with UMIN-CTR, number 000030364, on 12 December 2017.

Establishment and characterization of a novel vincristine-resistant diffuse large B-cell lymphoma cell line containing the 8q24 homogeneously staining region.

Chromosome band 8q24 is the most frequently amplified locus in various types of cancers. MYC has been identified as the primary oncogene at the 8q24 locus, whereas a long noncoding gene, PVT1, which lies adjacent to MYC, has recently emerged as another potential oncogenic regulator at this position. In this study, we established and characterized a novel cell line, AMU-ML2, from a patient with diffuse large B-cell lymphoma (DLBCL), displaying homogeneously staining regions at the 8q24 locus. Fluorescence in situ hybridization clearly detected an elevation in MYC copy numbers corresponding to the homogenously staining region. In addition, a comparative genomic hybridization analysis using high-resolution arrays revealed that the 8q24 amplicon size was 1.4 Mb, containing the entire MYC and PVT1 regions. We also demonstrated a loss of heterozygosity for TP53 at 17p13 in conjunction with a TP53 frameshift mutation. Notably, AMU-ML2 cells exhibited resistance to vincristine, and cell proliferation was markedly inhibited by MYC-shRNA-mediated knockdown. Furthermore, genes involved in cyclin D, mTOR, and Ras signaling were downregulated following MYC knockdown, suggesting that MYC expression was closely associated with tumor cell growth. In conclusion, AMU-ML2 cells are uniquely characterized by homogenously staining regions at the 8q24 locus, thus providing useful insights into the pathogenesis of DLBCL with 8q24 abnormalities.