RESUMEN
The cytokine IL-6 controls the survival, proliferation and effector characteristics of lymphocytes through activation of the transcription factors STAT1 and STAT3. While STAT3 activity is an ever-present feature of IL-6 signaling in CD4+ T cells, prior activation via the T cell antigen receptor limits IL-6's control of STAT1 in effector and memory populations. Here we found that phosphorylation of STAT1 in response to IL-6 was regulated by the tyrosine phosphatases PTPN2 and PTPN22 expressed in response to the activation of naïve CD4+ T cells. Transcriptomics and chromatin immunoprecipitation-sequencing (ChIP-seq) of IL-6 responses in naïve and effector memory CD4+ T cells showed how the suppression of STAT1 activation shaped the functional identity and effector characteristics of memory CD4+ T cells. Thus, tyrosine phosphatases induced by the activation of naïve T cells determine the way activated or memory CD4+ T cells sense and interpret cytokine signals.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Factor de Transcripción STAT1/metabolismo , Transducción de Señal , Animales , Artritis Reumatoide/enzimología , Artritis Reumatoide/patología , Linfocitos T CD4-Positivos/enzimología , Células CHO , Células Cultivadas , Cricetulus , Regulación de la Expresión Génica , Humanos , Memoria Inmunológica , Interleucina-6/fisiología , Activación de Linfocitos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Regiones Promotoras Genéticas , Proteína Tirosina Fosfatasa no Receptora Tipo 2/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores de Interleucina-6/fisiología , Membrana Sinovial/inmunología , Transcripción GenéticaRESUMEN
We present a laboratory-based prognostic calculator (designated CRO score) to risk stratify treatment-free survival in early stage (Rai 0) chronic lymphocytic leukemia (CLL) developed using a training-validation model in a series of 1,879 cases from Italy, the United Kingdom and the United States. By means of regression analysis, we identified five prognostic variables with weighting as follows: deletion of the short arm of chromosome 17 and unmutated immunoglobulin heavy chain gene status, 2 points; deletion of the long arm of chromosome 11, trisomy of chromosome 12, and white blood cell count >32.0x103/microliter, 1 point. Low-, intermediate- and high-risk categories were established by recursive partitioning in a training cohort of 478 cases, and then validated in four independent cohorts of 144 / 395 / 540 / 322 cases, as well as in the composite validation cohort. Concordance indices were 0.75 in the training cohort and ranged from 0.63 to 0.74 in the four validation cohorts (0.69 in the composite validation cohort). These findings advocate potential application of our novel prognostic calculator to better stratify early-stage CLL, and aid case selection in risk-adapted treatment for early disease. Furthermore, they support immunocytogenetic analysis in Rai 0 CLL being performed at the time of diagnosis to aid prognosis and treatment, particularly in today's chemofree era.
Asunto(s)
Leucemia Linfocítica Crónica de Células B , Humanos , Italia , Laboratorios , Leucemia Linfocítica Crónica de Células B/diagnóstico , Leucemia Linfocítica Crónica de Células B/genética , Leucemia Linfocítica Crónica de Células B/terapia , Mutación , Pronóstico , Reino UnidoRESUMEN
The frequency and severity of episodes of peritonitis adversely affect the structure and function of the peritoneal membrane in patients treated with peritoneal dialysis (PD), but the underlying mechanisms are not well understood. Alterations in the phenotype and function of resident peritoneal cells may contribute. Because effector memory T cells play a pivotal role in maintaining peripheral tissue immunity, we hypothesized that these cells may initiate or perpetuate the peritoneal inflammatory response. Here, we characterized the phenotype and effector function of peritoneal memory T cells. We found that functional effector memory T cells capable of mounting long-term recall responses enrich the peritoneal cavity of PD patients. Peritoneal T cells were able to mount a Th1-polarized response to recall antigens, and these responses were greater in peritoneal T cells compared with T cells in the peripheral blood. We also observed that the peritoneal T cells had altered telomeres; some cells had ultrashort telomeres, suggesting a highly differentiated local population. In summary, we describe a resident population of memory T cells in the peritoneum of PD patients and speculate that these cells form part of the first line of defense against invading pathogens.
Asunto(s)
Memoria Inmunológica/inmunología , Fallo Renal Crónico/inmunología , Fallo Renal Crónico/terapia , Diálisis Peritoneal/efectos adversos , Peritonitis/inmunología , Humanos , Cavidad Peritoneal/patología , Peritonitis/patología , Linfocitos T/citología , Linfocitos T/inmunologíaRESUMEN
Uptake of fluorescein isothiocynate-dextran (FITC-dextran) by Chinese hamster ovary cells was studied after exposure to ultrasonic standing wave (USW) in presence of Optison, an ultrasound contrast agent. Confluent Chinese hamster ovary cells were harvested and suspended in phosphate-buffered saline + 0.1% bovine serum albumin containing FITC-dextran (10, 40, and 500 kDa) at 10 microM final concentration. The suspension was seeded with contrast agent (75 microL/mL) and exposed to a 1.5 MHz USW system at acoustic pressures ranging from 0.98 to 4.2 MPa. Macromolecular uptake was assessed by fluorescent microscopy and quantified by flow cytometry 10 min after exposure. FITC-dextran positive cells, as assessed by flow cytometry, were 1 +/- 0.05% and 2.58 +/- 0.27% for acoustic pressures of 1.96 and 4.2 MPa, respectively (p = 0.006). Fluorescent microscopy indicated a degree of macromolecular loading at 0.98 MPa with 46% of peripherally FITC-dextran- and/or propidium iodide-stained cells coincident with the appearance of significant frequency (f0/2 and 2 f0) emission signals. At higher pressures, high macromolecular loading with 6% peripherally stained cells at 1.96 MPa was associated with lower order emission signals and white noise. The study conclusively demonstrates macromolecular loading in an USW, a significantly higher macromolecular loading at higher pressures and indicates potential of emission signals for a feedback loop to control the acoustic power outputs and fine-tune the biologic effects associated with sonoporation.
Asunto(s)
Albúminas/farmacología , Medios de Contraste/farmacología , Dextranos/farmacocinética , Fluoresceína-5-Isotiocianato/análogos & derivados , Fluorocarburos/farmacología , Ultrasonido , Animales , Células CHO/diagnóstico por imagen , Células CHO/metabolismo , Separación Celular/métodos , Supervivencia Celular , Cricetinae , Cricetulus , Citometría de Flujo/métodos , Fluoresceína-5-Isotiocianato/farmacocinética , Microscopía Fluorescente/métodos , Peso Molecular , Presión , Sonicación , UltrasonografíaRESUMEN
SJG-136 (NSC 694501) is a novel DNA cross-linking agent that binds in a sequence-selective manner in the minor groove of the DNA helix. It is structurally novel compared with other clinically used DNA cross-linking agents and has exhibited a unique multilog differential pattern of activity in the NCI 60-cell line screen (i.e., is COMPARE negative to other cross-linking agents). Given this profile, we undertook a preclinical evaluation of SJG-136 in primary tumor cells derived from 34 B-cell chronic lymphocytic leukemia (B-CLL) patients. SJG-136 induced apoptosis in all of the B-CLL samples tested with a mean LD50 value (the concentration of drug required to kill 50% of the cells) of 9.06 nmol/L. Its cytotoxicity was undiminished in B-CLL cells derived from patients treated previously, those with unmutated VH genes, and those with p53 mutations (P=0.17; P=0.63; P=0.42, respectively). SJG-136-induced apoptosis was associated with the activation of caspase-3 that could be partially abrogated by the caspase-9 inhibitor Z-LEHD-FMK. Furthermore, SJG-136 did not trigger the phosphorylation of p53 or the up-regulation of GADD45 expression in B-CLL cells whereas the cross-linking agent chlorambucil elicited both of these effects. This suggests that SJG-136 cross-linking adducts are not subject to p53-mediated DNA excision repair mechanisms in B-CLL cells. Taken together, these data demonstrate a novel mechanism of action for SJG-136 that appears to circumvent the effects of poor prognostic markers. This unique cytotoxicity profile warrants further investigation and supports the evaluation of this agent in Phase I clinical trials for patients with B-CLL.
Asunto(s)
Benzodiazepinonas/farmacología , Reactivos de Enlaces Cruzados/farmacología , Leucemia Linfocítica Crónica de Células B/tratamiento farmacológico , Pirroles/farmacología , Proteína p53 Supresora de Tumor/fisiología , Vidarabina/análogos & derivados , Apoptosis/efectos de los fármacos , Linfocitos B/citología , Linfocitos B/efectos de los fármacos , Linfocitos B/patología , Benzodiazepinas/farmacología , Estudios de Casos y Controles , Caspasa 3 , Caspasas/metabolismo , Daño del ADN , Reparación del ADN , Activación Enzimática , Humanos , Células K562 , Leucemia Linfocítica Crónica de Células B/sangre , Leucemia Linfocítica Crónica de Células B/genética , Leucemia Linfocítica Crónica de Células B/patología , Linfocitos T/citología , Linfocitos T/efectos de los fármacos , Linfocitos T/patología , Células Tumorales Cultivadas , Vidarabina/farmacologíaRESUMEN
The synthesis of imidazole styrylbenzamide, tert-butyl styrylimidazole, and tert-butyl styrylsulfonate derivatives is described. Evaluation of binding affinity and inhibitory activity against CYP24A1 identified the imidazole styrylbenzamides as potent inhibitors of CYP24A1, having selectivity with respect to CYP27B1 comparable with or greater than that of the standard ketoconazole. Further evaluation of the 3,5-dimethoxy and 3,4,5-trimethoxy derivatives in chronic lymphocytic leukemia cells revealed that co-treatment of 1α,25-dihydroxyvitamin D3 plus inhibitor coordinately upregulated GADD45α and CDKN1A. Docking experiments on the inhibitors in the CYP24A1 enzyme active site suggest the compounds reach the active site through the vitamin D access tunnel and are exposed to multiple hydrophobic residues. The imidazole styrylbenzamides are optimally positioned to allow interaction of the imidazole with the heme, and, in the case of the methoxy derivatives, a hydrogen bond between the 3-methoxy group and Gln82 stabilizes the molecule in a favorable active conformation.