The 90-kDa heat shock protein (HSP90) is implicated in the conformational maturation and stabilization of a variety of client proteins with receptor and signal transduction functions. The objective of this study was to assess its expression in primary acute myeloid leukemia (AML) cells and to evaluate its biological and clinical significance. The in vitro effects of 17-AAG, a selective inhibitor of HSP90, was also evaluated. Cells from 65 patients with newly diagnosed AML were studied. The expression of HSP90 correlated with that of CD34, p170, and bcl-2 proteins but not with white cell counts, FAB or WHO subtype, or cytogenetics. HSP90 levels were also higher in samples exhibiting an autonomous growth in liquid culture or forming spontaneous colonies. A concomitant constitutive activation of the extracellular signal-regulated kinase and phosphatidylinositol 3-kinase/AKT pathways was observed in a majority of samples and was significantly correlated with HSP90 expression. All patients received induction chemotherapy. The percentages of HSP90-, CD34-, bcl-2-, and p170-positive cells were higher in patients who did not attain complete remission. Survival was also shorter in patients with high levels of HSP90. In vitro exposure of leukemic cells to 17-allylamino-demethoxy geldanamycin (17-AAG) resulted in inhibition of growth in liquid and clonogeneic cultures and in apoptosis, at concentrations which in most cases were not toxic for normal CD34-positive or progenitor cells. The concentration inhibiting 50% growth at 72 h in liquid culture correlated with HSP90 expression. Our study suggests that HSP90 is overexpressed in poor-prognosis AML cells and plays a role in cell survival and resistance to chemotherapy. Targeted therapy with 17-AAG represents a promising antileukemic strategy in adult AML.

Obstructive sleep apnea (OSA) is characterized by repeated episodes of intermittent hypoxia (IH) and is recognized as an independent risk factor for vascular diseases that are mediated by a multitude of mechanistic pathophysiological cascades including procoagulant factors. The pro-coagulant state contributes to the development of blood clots and to the increase in the permeability of the blood–brain barrier (BBB). Such alteration of BBB may alter brain function and increase the risk of neurodegenerative diseases. We aim to provide a narrative review of the relationship between the hypercoagulable state, observed in OSA and characterized by increased coagulation factor activity, as well as platelet activation, and the underlying neural dysfunction, as related to disruption of the BBB. We aim to provide a critical overview of the existing evidence about the effect of OSA on the coagulation balance (characterized by increased coagulation factor activity and platelet activation) as on the BBB. Then, we will present the emerging data on the effect of BBB disruption on the risk of underlying neural dysfunction. Finally, we will discuss the potential of OSA therapy on the coagulation balance and the improvement of BBB.

Acute myeloid leukemia is driven by leukemic stem cells which can be identified by cross lineage expression or arrest of differentiation compared to normal hematopoietic stem cells. Self-renewal and lack of differentiation are also features of stem cells and have been associated with the expression of embryonic genes. The aim of our study was to evaluate the expression of embryonic antigens (OCT4, NANOG, SOX2, SSEA1, SSEA3) in hematopoietic stem cell subsets (CD34⁺CD38⁻ and CD34⁺CD38⁺) from normal bone marrows and in samples from acute myeloid leukemia patients. We observed an upregulation of the transcription factors OCT4 and SOX2 in leukemic cells as compared to normal cells. Conversely, SSEA1 protein was downregulated in leukemic cells. The expression of OCT4, SOX2, and SSEA3 was higher in CD34⁺CD38⁻ than in CD34⁺CD38⁺ subsets in leukemic cells. There was no correlation with biological characteristics of the leukemia. We evaluated the prognostic value of marker expression in 69 patients who received an intensive treatment. The rate of complete remission was not influenced by the level of expression of markers. Overall survival was significantly better for patients with high SOX2 levels, which was unexpected because of the inverse correlation with favorable genetic subtypes. These results prompt us to evaluate the potential role of these markers in leukemogenesis and to test their relevance for better leukemic stem cell identification.

Therapy-related myeloid neoplasms (t-MN), including myelodysplastic neoplasms (t-MDS) and acute myeloid leukemia (t-AML), have emerged as significant late complications after CAR T cell therapy. We retrospectively analyzed 539 patients with B cell lymphoma treated with CD19 directed CAR T cell therapy across four French centers. Cumulative incidences of t-MN was estimated with relapse or death treated as competing risk. Univariate and propensity score matching (PSM) analyses were conducted to assess risk factors with age and the number of prior treatments as covariates. After a median follow-up of 25 months, the cumulative incidence of t-MN was 4.5% at 2 years. T-MN occurred predominantly as t-MDS (62%) and t-AML (38%) with high cytogenetic risk. Median overall survival after t-MN diagnosis was 4.5 months. In univariate analysis, older age (p < 0.01), higher MCV (p < 0.01), and higher ICANS grade (p = 0.04) were associated with increased risk of t-MN. After PSM, MCV and ICANS grade remained significant risk factors. CAR T cell products with CD28 co-stimulatory domains trended towards higher t-MN risk (p = 0.09). NGS analysis showed that 85.7% of t-MN had pre-existing mutations, most commonly TP53. This study highlights t-MN as a severe late complication of CAR T cell therapy. MCV and ICANS grade were identified as key risk factors.

Https://doi.org/10.18632/oncotarget.27652 Alexis Genthon, Franck Emmanuel Nicolini, Françoise Huguet, Carole Colin-Gil, Marc Berger, Sandrine Saugues, Alexandre Janel, Sandrine Hayette, Pascale...