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Objectives: Although high-throughput sequencing is revolutionising medicine, data on the actual cost of whole exome sequencing (WES) applications are needed. We aimed at assessing the cost of WES at a French cancer institute in 2015 and 2018. Methods: Actual costs of WES application in oncology research were determined using both micro-costing and gross-costing for the years 2015 and 2018, before and after the acquisition of a new sequencer. The entire workflow process of a WES test was tracked, and the number and unit price of each resource were identified at the most detailed level, from library preparation to bioinformatics analyses. In addition, we conducted an ad hoc analysis of the bioinformatics storage costs of data issued from WES analyses. Results: The cost of WES has decreased substantially, from €1921 per sample (i.e. cost of €3842 per patient) in 2015 to €804 per sample (i.e. cost of €1,608 per patient) in 2018, representing a decrease of 58%. In the meantime, the cost of bioinformatics storage has increased from €19,836 to €200,711. Conclusion: This study suggests that WES cost has decreased significantly in recent years. WES has become affordable, even though clinical utility and efficiency still need to be confirmed. [ABSTRACT FROM AUTHOR]

In addition to their cytoprotective role in stressful conditions, heat shock proteins (HSPs) are involved in specific differentiation pathways, for example, we have identified a role for HSP90 in macrophage differentiation of human peripheral blood monocytes that are exposed to macrophage colony-stimulating factor (M-CSF). Here, we show that deletion of the main transcription factor involved in heat shock gene regulation, heat shock factor 1 (HSF1), affects M-CSF-driven differentiation of mouse bone marrow cells. HSF1 transiently accumulates in the nucleus of human monocytes undergoing macrophage differentiation, including M-CSF-treated peripheral blood monocytes and phorbol ester-treated THP1 cells. We demonstrate that HSF1 has a dual effect on SPI1/PU.1, a transcription factor essential for macrophage differentiation and whose deregulation can lead to the development of leukemias and lymphomas. Firstly, HSF1 regulates SPI1/PU.1 gene expression through its binding to a heat shock element within the intron 2 of this gene. Furthermore, downregulation or inhibition of HSF1 impaired both SPI1/PU.1-targeted gene transcription and macrophage differentiation. Secondly, HSF1 induces the expression of HSP70 that interacts with SPI1/PU.1 to protect the transcription factor from proteasomal degradation. Taken together, HSF1 appears as a fine-tuning regulator of SPI1/PU.1 expression at the transcriptional and post-translational levels during macrophage differentiation of monocytes. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which discusses V617F mutation of the protein kinase Janus Kinase 2 (JAK2) which is the most predominant genetic abnormality in the three myeloproliferative neoplasms (MPNs) including myelofibrosis, essential thrombocythemia, and polycythemia vera.

Although other mutations may predate the acquisition of the JAK2V617F mutation, the latter is sufficient to drive the disease phenotype observed in BCR-ABL-negative myeloproliferative neoplasms (MPNs). One of the consequences of JAK2V617F is genetic instability that could explain JAK2V617F-mediated MPN progression and heterogeneity. Here, we show that JAK2V617F induces the accumulation of reactive oxygen species (ROS) in the hematopoietic stem cell compartment of a knock-in (KI) mouse model and in patients with JAK2V617F MPNs. JAK2V617F-dependent ROS elevation was partly mediated by an AKT-induced decrease in catalase expression and was accompanied by an increased number of 8-oxo-guanines and DNA double-strand breaks (DSBs). Moreover, there was evidence for a mitotic recombination event in mice resulting in loss of heterozygosity of Jak2V617F. Mice engrafted with 30% of Jak2V617F KI bone marrow (BM) cells developed a polycythemia vera-like disorder. Treatment with the anti-oxidant N-acetylcysteine (NAC) substantially restored blood parameters and reduced damages to DNA. Furthermore, NAC induced a marked decrease in splenomegaly with reduction in the frequency of the Jak2V617F-positive hematopoietic progenitors in BM and spleen. Altogether, overproduction of ROS is a mediator of JAK2V617F-induced DNA damages that promote disease progression. Targeting ROS accumulation might prevent the development of JAK2V617F MPNs. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding the somatic mutations of the colony-stimulating factor-3 receptor gene (CSF3R), which can be identified in patients with chronic myelomonocytic leukemia (CMML).

Procaspase-2S has been reported to selectively prevent membrane blebbing and apoptotic body formation in human monocytic-like leukemic U937 cells after etoposide (VP-16) treatment (Droinet al.,Oncogene20. 260-269, 2001). Here, we show that procaspase-2S overexpressed in human B lymphoma Namalwa cells inhibits procaspase-3 processing and activation, preventing cleavage and activation of Rho GTPase-associated ROCK-1 kinase. Failure of ROCK-1 activation in Namalwa cells correlates with a sustained delay in the appearance of membrane blebbing and apoptotic body formation after VP-16 treatment. Reciprocal coimmunoprecipitation experiments indicate that procaspase-2S binds to procaspase-3, but not procaspase-2L and -9 in untreated and VP-16-treated Namalwa cells. These data suggest that procaspase-2S-mediated anti-apoptotic effects are associated with inhibition of the processing and activation of procaspase-3 in VP-16-treated cells. [ABSTRACT FROM AUTHOR]

Most chemotherapeutic drugs can induce tumor cell death by apoptosis. Analysis of the molecular mechanisms that regulate apoptosis has indicated that anticancer agents simultaneously activate several pathways that either positively or negatively regulate the death process. The main pathway from specific damage induced by the drug to apoptosis involves activation of caspases in the cytosol by pro-apoptotic molecules such as cytochrome c released from the mitochondrial intermembrane space. At least in some cell types, anticancer drugs also upregulate the expression of death receptors and sensitize tumor cells to their cognate ligands. The Fas-mediated pathway could contribute to the early steps of drug-induced apoptosis while sensitization to the cytokine TRAIL could be used to amplify the response to cytotoxic drugs. The Bcl-2 family of proteins, that includes anti- and pro-apoptotic molecules, regulates cell sensitivity mainly at the mitochondrial level. Anticancer drugs modulate their expression (eg through p53-dependent gene transcription), their activity (eg by phosphorylating Bcl-2) and their subcellular localization (eg by inducing the translocation of specific BH3-only pro-apoptotic proteins). Very early after interacting with tumor cells, anticancer drugs also activate lipid-dependent signaling pathways that either increase or decrease cell ability to die by apoptosis. In addition, cytotoxic agents can activate protective pathways that involve activation of NFkappaB transcription factor, accumulation of heat shock proteins such as Hsp27 and activation of proteins involved in cell cycle regulation. This review discusses how modulation of the balance between noxious and protective signals that regulate drug-induced apoptosis could be used to improve the efficacy of current therapeutic regimens in hematological malignancies. [ABSTRACT FROM AUTHOR]

Proteolytic cleavage of a limited number of cellular proteins is a central biochemical feature of apoptosis. Aspartate-specific cysteine proteases, the so-called ‘caspases’, are the main enzymes involved in this process. At least ten homologues of interleukin-1β converting enzyme (ICE), the first described human caspase, have been identified so far. The purified active proteins are heterodimers with a long and a short subunit derived from a common inactive precursor. Crystallized ICE has an original tetrameric structure. The various caspases tend to show high degrees of homology around the active site Cys. Proteolysis by caspases minimally requires a tetrapeptide substrate in which Asp is an absolute requirement in P1 position, the P4 substrate residue is unique to each homologue, and much more widespread amino acid substitution is observed in P2 and P3. Caspase activation might involve a proteolytic cascade similar to that of the coagulation cascade but the molecular ordering of these proteases in vivo remains to be established clearly. Calpains, serine proteases, granzymes and the proteasome–ubiquitin pathway of protein degradation are other proteolytic pathways that have been suggested to play a role in apoptosis. Substrate proteins can be either activated or degraded during cell death and the consequences of their cleavage remains mostly ill-understood. Nevertheless, the recent demonstration that protease inhibitors can rescue mice undergoing acute liver destruction indicates the accuracy of therapeutic strategies aiming to inhibit cell death-associated proteolysis. [ABSTRACT FROM AUTHOR]

Caspases are aspartate-specific cysteine proteases that play a pivotal role in drug-induced cell death. We designed RT–PCR assays to analyse the expression of CASP-3, CASP-4, CASP-6 and the long and short isoforms of CASP-2 genes in human cells. These genes heterogeneously coexpress in leukemic cell lines and bone marrow samples from patients with de novo acute myelogenous leukemia at diagnosis. Treatment of U937 and HL60 leukemic cells and HT29 colon carcinoma cells with the topoisomerase II inhibitor etoposide upregulates CASP-2 and CASP-3 genes in these cells before inducing their apoptosis. This effect of etoposide is not observed in K562 cells and bcl-2-transfected U937 cells which are less sensitive to drug-induced apoptosis. Nuclear run-on experiments demonstrate that etoposide increases CASP gene transcription in U937 cells, an effect that is prevented by Bcl-2 overexpression. Upregulation of CASP genes is associated with an enhanced synthesis of related procaspases that precedes the appearance of apoptosis markers including caspase-3 activation, poly(ADP-ribose) polymerase cleavage and internucleosomal DNA fragmentation. These results suggest that the ability of tumor cells to upregulate CASP-2 and CASP-3 genes in response to cytotoxic drugs could be predictive of their sensitivity to drug-induced apoptosis. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article on the presence of SETBP1 mutations in patients with chronic myelomomocytic leukemia, secondary acute myeloid leukemias and myelodysplastic syndromes.