Activated Stat Related Transcription Factors in Acute Leukemia

International audienceCell proliferation and differentiation are under the control of cytokines and growth factors. Different signaling pathways are involved in the transmission of a specific signal through successive phosphorylation and dephosphorylation of proteins leading to gene transcription necessary for growth and differentiation. The cytokines and growth factors activate the Stat family of transcription factors. The Jak-Stat pathway is essential for cytokine signal transduction. Dysregulation of this cascade might lead to uncontrolled hematopoiesis. Studies have been carried out to examine the functionality of this pathway in cells from patients with acute leukemia. Members of the Stat protein family (Stat1, Stat3 and Stat5) are constitutively activated in cells collected from some acute leukemias suggesting dysregulation of the Jak-Stat pathway. Evidence of the existence of constitutively activated spliced variants of Stat3 and Stat5 proteins are described. The mechanisms of such activation remain to be clarified

Critical limb ischemia: thrombogenic evaluation of two autologous cell therapy products and biologic profile in treated patients

International audienceBackground: Cell therapy has been proposed as a salvage limb procedure in critical limb ischemia (CLI). Autologous cell therapy products (CTP) are obtained from patients with advanced peripheral arterial disease to be injected at the site of ischemia. Thrombogenicity of CTPs has not yet been assessed. The objectives were: 1) to assess thrombotic risk in candidates for cell therapy, 2) to evaluate two different CTPs in terms of thrombogenic potential, and 3) to evaluate clinical thrombotic events.Study design and methods: In this ancillary study of a Phase I and II clinical trial, bone marrow (BM)-CTPs (n = 20) and CTPs obtained by cytapheresis (peripheral blood [PB]-CTPs; n = 20) were compared. Inflammatory and coagulation markers were measured at baseline and 24 hours after CTP implantation. CTP cell content and tissue factor (TF) expression (mRNA and protein) were analyzed. Thrombin generation assessed CTP-related thrombogenicity.Results: All patients presented cardiovascular risk factors. At baseline, the patients' biologic profile was characterized by high levels of fibrinogen, C-reactive protein (CRP), D-dimer, interleukin (IL)-6, and plasmatic TF, whereas IL-10 was low. Although different in terms of cell composition, both BM- and PB-CTPs support low thrombin generation. Twenty-four hours after implantation, biologic markers remained stable in the PB-CTP group, except for IL-6. In the BM-CTP group, a significant increase of IL-6 but also of CRP and D-dimer was observed. Clinically, one single patient developed deep vein thrombosis 24 hours after the implantation of autologous PB-CTP.Conclusion: CTPs supported low thrombin generation and were well tolerated after calf implantation

ZAP-70 tyrosine kinase is constitutively expressed and phosphorylated in B-lineage acute lymphoblastic leukemia cells.

International audienceACKGROUND AND OBJECTIVES: Zeta-associated protein 70 (ZAP-70), a member of the Syk family of protein tyrosine kinases, is normally expressed in T and NK cells. While little is known about ZAP-70 expression in normal human B cells, it has been reported that ZAP-70 is expressed in a subset of patients with chronic lymphocytic leukemia (CLL) with a poor prognosis. In this study, we examined the expression and phosphorylation status of ZAP-70 in B-lineage acute lymphoblastic leukemia (Blin-ALL).DESIGN AND METHODS: First, ZAP-70 protein expression was assessed by Western blotting and flow cytometry and ZAP-70 mRNA transcripts were analyzed by reverse transcription polymerase chain reaction (RT-PCR) on human precursor B cell lines. Experiments were then carried out on cells obtained from 18 patients with Blin-ALL and from normal human bone marrow.RESULTS: ZAP-70 was constitutively expressed and phosphorylated on tyr319 in human precursor Blin-ALL cell lines as well as in primary B leukemic cells from all examined Blin-ALL patients with pro-B, pre-B and B phenotypes, but not in malignant myeloid cells. Importantly, analysis of normal human bone marrow revealed expression of ZAP-70 transcripts only in the CD34+ cell fraction (either CD19-CD10- or CD19+CD10+) but not in the CD34- cell fraction (CD19+sIgM- pre-B cells or CD19+sIgM+ immature B cells).INTERPRETATION AND CONCLUSIONS: ZAP-70 was found to be expressed in the CD34+ normal bone marrow compartment including earlier B-cell progenitors, but not in CD34- pre-B and immature B cells. By contrast, ZAP-70 was consistently expressed and phosphorylated in Blin-ALL cells. Further studies are required to determine whether ZAP-70 may play a pathophysiological role in Blin-ALL.

High Milk Consumption Does Not Affect Prostate Tumor Progression in Two Mouse Models of Benign and Neoplastic Lesions

<div><p>Epidemiological studies that have investigated whether dairy (mainly milk) diets are associated with prostate cancer risk have led to controversial conclusions. In addition, no existing study clearly evaluated the effects of dairy/milk diets on prostate tumor progression, which is clinically highly relevant in view of the millions of men presenting with prostate pathologies worldwide, including benign prostate hyperplasia (BPH) or high-grade prostatic intraepithelial neoplasia (HGPIN). We report here a unique interventional animal study to address this issue. We used two mouse models of fully penetrant genetically-induced prostate tumorigenesis that were investigated at the stages of benign hyperplasia (probasin-Prl mice, Pb-Prl) or pre-cancerous PIN lesions (KIMAP mice). Mice were fed high milk diets (skim or whole) for 15 to 27 weeks of time depending on the kinetics of prostate tumor development in each model. Prostate tumor progression was assessed by tissue histopathology examination, epithelial proliferation, stromal inflammation and fibrosis, tumor invasiveness potency and expression of various tumor markers relevant for each model (c-Fes, Gprc6a, activated Stat5 and p63). Our results show that high milk consumption (either skim or whole) did not promote progression of existing prostate tumors when assessed at early stages of tumorigenesis (hyperplasia and neoplasia). For some parameters, and depending on milk type, milk regimen could even exhibit slight protective effects towards prostate tumor progression by decreasing the expression of tumor-related markers like Ki-67 and Gprc6a. In conclusion, our study suggests that regular milk consumption should not be considered detrimental for patients presenting with early-stage prostate tumors.</p></div

List of primers used for q RT-PCR.

<p>List of primers used for q RT-PCR.</p

Effect of milk diets on expression of tumor markers.

<p>Various tumor markers relevant to Pb-Prl (A) and KIMAP (B and C) models were assessed in DP following 27- or 15-week milk diets respectively, as compared to control (water) group. Proliferation index (Ki-67 staining, shown for both models), activated Stat5 (p-Stat5) and p63 expression (for Pb-Prl mice) and c-Fes expression (for KIMAP mice) were assessed from immunohistochemical (IHC) analysis (n = 6 per group; pictures show representative staining, scale stands for 50μm). For each marker (except c-Fes), IHC were quantified and the results are represented on adjacent bar histograms and are expressed as fold change <i>vs</i>. control (water) group. L, lumen of the glands. (C) q RT-PCR analysis of c-Fes, Ki-67 and Gprc6a mRNA expression in DP of KIMAP mice following 15-week milk diets. Results are expressed as fold change <i>vs</i>. control (water) group and are shown as means ± S.D. P values are represented <i>vs</i>. water control group (*). <i>nd</i>, for not determined.</p

Animal weight gain and prostate weight following milk diets.

<p>Animal weight gain between 3 weeks of age (i.e. at the beginning of the different diets) and sacrifice (A) and prostate weights at sacrifice (B) are reported for Pb-Prl and KIMAP mice in all diet groups. Animal weight gain is expressed in grams (g) while prostate weights are represented as the ratio between half prostate weight and mouse weight (g). Each dot represents one animal (n = 10 mice per group); horizontal lines represent the mean of the group. P values are represented <i>vs</i>. water control group (*), or <i>vs</i>. whole milk group (#).</p

Mouse models and diet protocols.

<p>(A) Representation of the two mouse models of prostate tumorigenesis used in this study. The Pb-Prl transgenic model shown on the left involves overexpression of rat prolactin under the control of the probasin promoter. The KIMAP model shown on the right involves the knock-in of SV40 large T antigen at the PSP94 locus. Respective protocols for milk diet administration (B) are shown below each model. For both, milk was introduced at 3 weeks of age and milk diets lasted for the indicated duration. Mice were sacrificed at the end of regimens.</p

Composition of diets.

<p>Composition of diets.</p