Mice lacking miR-146a exhibit exaggerated inflammatory responses, autoimmunity, and increased rate of tumorigenesis.

Conventional cancer therapies are based on preferential killing of tumor cells by DNA damage. Previous work showed that, for certain cell types, loss of integrin-mediated adhesion decreased the apoptotic response to DNA damage because of decreased p53 levels after detachment from the extracellular matrix. Integrin ligation restored p53 and sensitivity to DNA damage. In this study, we show that c-Abl mediates a second pathway by which adhesion to extracellular matrix regulates cell killing by chemotherapeutic agents 5-arabinofuranosylcytosine, cisplatin, and camptothecin. Activation of c-Abl tyrosine kinase by DNA damage requires cell adhesion. Abl-dependent stabilization of p73, a p53-related proapoptotic transcription factor, is also adhesion-dependent. Sensitivity to the Abl inhibitor STI571 suggests differential utilization of the p53 and c-Abl͞p73 pathways by different tumor cell lines. These data suggest that killing of p53-negative tumor cells by chemotherapy would be enhanced by integrin ligation to activate the alternative c-Abl͞p73 pathway.C urrent cancer therapies are based primarily on radiation and chemotherapy that damage DNA to selectively kill fastgrowing tumor cells. This strategy is efficacious in the treatment of childhood leukemia and solid tumors at early stages, but suffers from the limitation that a small number of cancer cells commonly evade therapy and accumulate additional mutations, leading to recurrence of therapy-resistant tumors. The tumor suppressor gene p53 provides a key pathway that mediates cell death after DNA damage (1, 2). DNA damage increases the level and the transcriptional activity of p53, resulting in induction of cell cycle arrest genes such as p21 Waf1 and proapoptotic genes such as Noxa, Puma, and Bax. Inactivation of p53 is one of the most common genetic alterations in human cancer and is associated with progression to metastatic disease, resistance to therapy, and genomic instability.We recently described an effect of integrin-mediated adhesion on p53 levels and subsequent sensitivity of cells to DNA damage (3). For susceptible cell types, loss of adhesion to extracellular matrix (ECM) caused a decrease in p53 levels, leading to decreased apoptosis after exposure to ionizing radiation or chemotherapeutic drugs. The change in p53 was caused by a more rapid decline in levels of p19Arf, which inhibits MDM2 to prevent ubiquitin-and proteosome-dependent degradation of p53. This behavior was cell type specific. It was observed in a melanoma, a rhabdomyosarcoma and a fibrosarcoma line, as well as primary mouse embryonic fibroblasts (MEFs). However, several other tumor cell types either died directly after detachment or showed no decrease in sensitivity to DNA damage in suspension.A second pathway that mediates cellular responses to DNA damage involves the c-Abl tyrosine kinase. Activation of c-Abl by DNA damage contributes to cell cycle arrest and apoptosis via the p53 homolog p73 (4-6). Interestingly, c-Abl is also regulated by integrins (7,8). Detachment of cells from th...

Although intended to induce an adaptive immune response against leukemia-associated antigens, infusion of CD154-expressing leukemia cells caused rapid reductions in leukemia-cell counts and lymph node size of the treated patients. 2 The kinetics of leukemia-cell clearance suggested that innate immune effector mechanisms contributed to the initial reduction in leukemia-cell counts following such treatment. Consistent with this notion, we found that both transduced and bystander CLL cells expressed extrinsic death receptors, Fas (CD95) and DR5, and acquired latent sensitivity to Fas/TRAIL-mediated apoptosis in vitro. 2,3 The expression of ligands for these death receptors could be found on natural killer (NK) cells and activated CD4 T cells that were present in the blood of patients following infusion of autologous, CD154-transduced leukemia cells. [2][3][4] Leukemia-cell expression of these death receptors could be mediated by p53. p53 can activate transcription and expression of a number of genes encoding proteins responsible for clearance of cells that experience nonrepairable genotoxic stress. Specifically, genes encoding CD95 and DR5 both have p53 binding elements in the promoter and/or first intron, allowing for their induced expression upon activation of p53. 5,6 Moreover, both receptors are induced by ␥-irradiation in a p53-dependent fashion (reviewed by Sheard 7 ). Also, p53 has been implicated in the induction of Bid, a molecule that also is expressed in CLL cells stimulated by CD154 4,8 and that can sensitize tumor cells to many anticancer drugs. 9 Because CD40-ligation on CLL cells can induce p53, 10 we hypothesized that p53 might play a role in the latent sensitization of CD154-treated CLL cells to Fas-mediated apoptosis. As such, the leukemia-cell expression of functional p53 may be critical for the expression of death receptors and/or latent sensitization to Fas/ TRAIL-mediated apoptosis following CD154 gene therapy.However, CLL cells can incur somatic deletions in the short arm of chromosome 17 and/or inactivating mutations in p53. 11 This is associated with resistance to standard anticancer drugs and poor prognosis. 12,13 Conceivably, loss of p53 function also could make leukemia cells incapable of expressing death receptors or in becoming sensitive to Fas/TRAIL-mediated apoptosis following treatment with CD154. As such, patients with leukemia cells harboring such defects may be resistant to CD154 gene therapy.However, some of the patients treated in early clinical trials had leukemia cells that apparently lacked p53 function yet still experienced acute reductions in leukemia-cell counts following Materials and methods CellsWe obtained blood from patients with CLL following written informed consent. The mononuclear cells were isolated by density centrifugation over Ficoll-Paque (Amersham Biosciences, Piscataway, NJ) and viably frozen in fetal bovine serum (FBS; Omega Scientific, Tarzana, CA) containing 10% DMSO. Chinese hamster ovary (CHO) cells and HeLa cells were obtained from the American Type...

Purpose: Checkpoint kinase 1 (Chk1) plays a critical role in the activation of mitotic spindle checkpoint and DNA damage checkpoint. We examined the preclinical use of the Chk1 inhibitor PF-00477736 as a docetaxel-sensitizing agent. Specifically, we investigated the correlation between PF-00477736^mediated modulation of biomarkers and the sensitization of docetaxel efficacy. Experimental Design: In vitro and in vivo studies using COLO205 and other cell lines were done to assess PF-00477736^induced enhancement of docetaxel efficacy and effects on associated biomarkers. Conclusions: Docetaxel triggers mitotic spindle checkpoint activation at low concentrations and activates both the DNA damage checkpoint and the spindle checkpoint at high concentrations. In combination with docetaxel, PF-00477736 abrogates the mitotic checkpoint, as well as the DNA damage checkpoint, and results in sensitization to docetaxel. Chk1inhibitor PF-00477736 offers a therapeutic potential for the enhancement of taxane therapy.

OBJECTIVE:Hemophagocytic lymphohistiocytosis in adults is largely underdiagnosed. To improve the rate and accuracy of diagnosis in adults, the clinical and laboratory characteristics of hemophagocytic lymphohistiocytosis were analyzed in and compared between adults and children in a Chinese cohort.METHOD:Data from 50 hemophagocytic lymphohistiocytosis patients, including 34 adults and 16 children who fulfilled the 2004 hemophagocytic lymphohistiocytosis diagnostic criteria, were collected and analyzed.RESULTS:1. Etiological factors: The proportion of Epstein-Barr virus infection was lower in adults compared with children, whereas fungal infection and natural killer/T cell lymphoma were more frequent in adults (P<0.05). 2. Clinical manifestations and laboratory findings: Over 90% of adults and pediatric patients presented with fever, thrombocytopenia and high serum ferritin levels. However, in adults, the proportions of hepatomegaly, splenomegaly and jaundice were much lower (P<0.01) than in children, and serous cavity effusion was more frequent in adult patients (P<0.05). More children had hemoglobin <90 g/L, total bilirubin >19 mmol/L and lactate dehydrogenase >500 U/L compared with adults (P<0.05). 3. The time interval from the onset of symptoms to clinical diagnosis was significantly shorter in pediatric patients than in adults (P<0.05).CONCLUSIONS:Certain clinical features were different between the two groups. The less characteristic clinical presentation of hemophagocytic lymphohistiocytosis in adults may make the disease more difficult to diagnose. Our findings suggest that hemophagocytic lymphohistiocytosis should be considered when an adult patient presents with the above-mentioned symptoms.

Congenital cataract is the most frequent inherited ocular disorder and the most leading cause of lifelong visual loss. The screening of pathogenic mutations can be very challenging in some cases, for congenital cataracts are clinically and genetically heterogeneous diseases. The aim of this study is to investigate the mutation spectrum and frequency of 54 cartaract-associated genes in 27 Chinese families with congenital cataracts. Variants in 54 cataract-associated genes were screened by targeted next-generation sequencing (NGS) and then validated by Sanger sequencing. We identified pathogenic variants in 62.96% (17/27) of families, and over 52.94% (9/17) of these variants were novel. Among them, three are splicing site mutations, four are nonsense mutations, seven are missense mutations, two are frame shift mutations and one is intronic mutation. This included identification of: complex ocular phenotypes due to two novel PAX6 mutations; progressive cortical cataract and lamellar cataract with lens subluxation due to two novel CRYGS mutations. Mutations were also found in rarely reported genes including CRYBA4, CRYBA2, BFSP1, VIM, HSF4, and EZR. Our study expands the mutation spectrum and frequency of genes responsible for congenital cataracts. Targeted next-generation sequencing in inherited congenital cataract patients provided significant diagnostic information.

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ABSTRACT. The aim of this study was to investigate the diagnostic value of the serum markers HBsAg and HBeAg and PreS1 protein (PreS1-Ag) in quantifying the levels of hepatitis B virus (HBV) DNA in patients with chronic hepatitis B (CHB). One thousand CHB patients were recruited from Beijing You'an Hospital between June and December 2012. Serum HBsAg and HBeAg levels were detected by electrochemiluminescence immunoassay. Enzyme-linked immunosorbent assay and fluorescence quantitative PCR were used to determine the level of PreS1-Ag and HBV DNA, respectively. We observed a low correlation between HBsAg and HBV DNA (r = 0.172, P < 0.001) expression; however, the correlation coefficient increased gradually with the increase in HBV DNA levels, and was more significant when HBV DNA log 10 > 7 (r = 0.597, P < 0.001). Additionally, HBsAg and HBV DNA showed a significant positive correlation in the HBeAg+ group (r = 0.321, P < 0.001), whereas no correlation was observed in the HBeAg-group (r = -0.016, P = 0.825). HBV DNA expression was correlated with HBeAg (c 2 = 83.07, P < 0.001) and PreS1-Ag (c 2 = 36.01, P < 0.001). HBV DNA-positive rate was higher in HBeAg/PreS1-Ag++ patients (72.26%) than that in the single-positive groups (P < 0.001). Therefore, serum HBsAg is not a good marker for the prediction of HBV replication, and co-detection of HBeAg and PreS1-Ag, which can better predict HBV DNA replication, can be used as a reliable method for the clinical diagnosis and treatment of CHB.