Decitabine Versus Hydroxyurea for Advanced Proliferative Chronic Myelomonocytic Leukemia: Results of a Randomized Phase III Trial Within the EMSCO Network.

PURPOSE: Hydroxyurea (HY) is a reference treatment of advanced myeloproliferative neoplasms. We conducted a randomized phase III trial comparing decitabine (DAC) and HY in advanced myeloproliferative chronic myelomonocytic leukemias (CMML). PATIENTS AND METHODS: Newly diagnosed myeloproliferative CMML patients with advanced disease were randomly assigned 1:1 to intravenous DAC (20 mg/m2/d days 1-5) or HY (1-4 g/d) in 28-day cycles. The primary end point was event-free survival (EFS), events being death and acute myelomonocytic leukemia (AML) transformation or progression. RESULTS: One-hundred seventy patients received DAC (n = 84) or HY (n = 86). Median age was 72 and 74 years, and median WBC count 32.5 × 109/L and 31.2 × 109/L in the DAC and HY arms, respectively. Thirty-three percent of DAC and 31% of HY patients had CMML-2. Patients received a median of five DAC and six HY cycles. With a median follow-up of 17.5 months, median EFS was 12.1 months in the DAC arm and 10.3 months in the HY arm (hazard ratio [HR], 0.83; 95% CI, 0.59 to 1.16; P = .27). There was no significant interaction between treatment effect and blast or platelet count, anemia, CMML Prognostic Scoring System, Groupe Francophone des Myelodysplasies, or CMML Prognostic Scoring System-mol risk. Fifty-three (63%) DAC patients achieved a response compared with 30 (35%) HY patients (P = .0004). Median duration of response was similar in both arms (DAC, 16.3 months; HY, 17.4 months; P = .90). Median overall survival was 18.4 months in the DAC arm and 21.9 months in the HY arm (P = .67). Compared with HY, DAC significantly reduced the risk of CMML progression or transformation to acute myelomonocytic leukemia (cause-specific HR, 0.62; 95% CI, 0.41 to 0.94; P = .005) at the expense of death without progression or transformation (cause-specific HR, 1.55; 95% CI, 0.82 to 2.9; P = .04). CONCLUSION: Compared with HY, frontline treatment with DAC did not improve EFS in patients with advanced myeloproliferative CMML (ClinicalTrials.gov identifier: NCT02214407).

DPP-4 is expressed in human pancreatic beta cells and its direct inhibition improves beta cell function and survival in type 2 diabetes.

It has been reported that the incretin system, including regulated GLP-1 secretion and locally expressed DPP-4, is present in pancreatic islets. In this study we comprehensively evaluated the expression and role of DPP-4 in islet alpha and beta cells from non-diabetic (ND) and type 2 diabetic (T2D) individuals, including the effects of its inhibition on beta cell function and survival. Isolated islets were prepared from 25 ND and 18 T2D organ donors; studies were also performed with the human insulin-producing EndoC-ßH1 cells. Morphological (including confocal microscopy), ultrastructural (electron microscopy, EM), functional (glucose-stimulated insulin secretion), survival (EM and nuclear dyes) and molecular (RNAseq, qPCR and western blot) studies were performed under several different experimental conditions. DPP-4 co-localized with glucagon and was also expressed in human islet insulin-containing cells. Furthermore, DPP-4 was expressed in EndoC-ßH1 cells. The proportions of DPP-4 positive alpha and beta cells and DPP-4 gene expression were significantly lower in T2D islets. A DPP-4 inhibitor protected ND human beta cells and EndoC-ßH1 cells against cytokine-induced toxicity, which was at least in part independent from GLP1 and associated with reduced NFKB1 expression. Finally, DPP-4 inhibition augmented glucose-stimulated insulin secretion, reduced apoptosis and improved ultrastructure in T2D beta cells. These results demonstrate the presence of DPP-4 in human islet alpha and beta cells, with reduced expression in T2D islets, and show that DPP-4 inhibition has beneficial effects on human ND and T2D beta cells. This suggests that DPP-4, besides playing a role in incretin effects, directly affects beta cell function and survival.

Palmitate-induced lipotoxicity alters acetylation of multiple proteins in clonal ß cells and human pancreatic islets.

Type 2 diabetes is characterized by progressive ß cell dysfunction, with lipotoxicity playing a possible pathogenetic role. Palmitate is often used to examine the direct effects of lipotoxicity and it may cause mitochondrial alterations by activating protein acetylation. However, it is unknown whether palmitate influences protein acetylation in ß cells. We investigated lysine acetylation in mitochondrial proteins from INS-1E ß cells (INS-1E) and in proteins from human pancreatic islets (HPI) after 24 h palmitate exposure. First, we confirmed that palmitate damages ß cells and demonstrated that chemical inhibition of deacetylation also impairs INS-1E function and survival. Then, by 2-D gel electrophoresis, Western Blot and Liquid Chromatography-Mass Spectrometry we evaluated the effects of palmitate on protein acetylation. In mitochondrial preparations from palmitate-treated INS-1E, 32 acetylated spots were detected, with 13 proteins resulting over-acetylated. In HPI, 136 acetylated proteins were found, of which 11 were over-acetylated upon culture with palmitate. Interestingly, three proteins, glutamate dehydrogenase, mitochondrial superoxide dismutase, and SREBP-1, were over-acetylated in both INS-1E and HPI. Therefore, prolonged exposure to palmitate induces changes in ß cell protein lysine acetylation and this modification could play a role in causing ß cell damage. Dysregulated acetylation may be a target to counteract palmitate-induced ß cell lipotoxicity.