Citations

Abstract A human IgM Ab, serum-derived human IgM 12 (sHIgM12), is identified that binds mouse and human dendritic cells (DC), inducing dramatic immunopotentiation following treatment of the mouse DC in vitro. Competition, transfection, and knockout studies identified the ligand on mouse DC as the costimulatory molecule family member B7-DC. Potent T cell responses are stimulated by Ag-pulsed DC treated with the sHIgM12 Ab in vitro and upon adoptive transfer of Ab-treated Ag-pulsed DC into animals. The multivalent structure of pentameric IgM provides the potential for cross-linking cell surface targets, endowing the soluble Abs with biological potential not normally associated with immune function. The ability of the sHIgM12 Ab to potentiate the immune response is dependent on the multimeric structure of IgM, as bivalent monomers do not retain this property. Furthermore, pretreatment of DC with IgM monomers blocks subsequent potentiation by intact IgM pentamers, an indication that cross-linking of B7-DC on the cell surface is critical for potentiation of Ag presentation. These findings imply that, in addition to known costimulatory roles, B7-DC can function as a receptor for signals delivered by cells expressing B7-DC ligands.

Abstract Biliary epithelial cells (cholangiocytes) respond to proinflammatory cytokines such as IFN-γ and actively participate in the regulation of biliary inflammatory response in the liver. B7-H1 (also known as CD274 or PD-L1) is a member of the B7 costimulatory molecules and plays a critical immunoregulatory role in cell-mediated immune responses. In this study, we show that resting human cholangiocytes in culture express B7-H1 mRNA, but not B7-H1 protein. IFN-γ induces B7-H1 protein expression and alters the microRNA (miRNA) expression profile in cholangiocytes. Of those IFN-γ-down-regulated miRNAs, we identified microRNA-513 (miR-513) with complementarity to the 3′-untranslated region of B7-H1 mRNA. Targeting of the B7-H1 3′-untranslated region by miR-513 results in translational repression. Transfection of cholangiocytes with an antisense oligonucleotide to miR-513 induces B7-H1 protein expression. Additionally, transfection of miR-513 precursor decreases IFN-γ-induced B7-H1 protein expression and consequently influences B7-H1-associated apoptotic cell death in cocultured Jurkat cells. Thus, miR-513 regulates B7-H1 translation and is involved in IFN-γ-induced B7-H1 expression in human cholangiocytes, suggesting a role for miRNA-mediated gene silencing in the regulation of cholangiocyte response to IFN-γ.

ABSTRACT Pneumocystis pneumonia (PcP) is a significant cause of morbidity and mortality in immunocompromised patients. In humans, PcP is caused by the opportunistic fungal species Pneumocystis jirovecii . Progress in Pneumocystis research has been hampered by a lack of viable in vitro culture methods, which limits laboratory access to human-derived organisms for drug testing. Consequently, most basic drug discovery research for P. jirovecii is performed using related surrogate organisms such as Pneumocystis carinii , which is derived from immunosuppressed rodents. While these studies provide useful insights, important questions arise about interspecies variations and the relative utility of identified anti- Pneumocystis agents against human P. jirovecii . Our recent work has identified the histone acetyltransferase (HAT) Rtt109 in P. carinii (i.e., PcRtt109) as a potential therapeutic target for PcP, since Rtt109 HATs are widely conserved in fungi but are absent in humans. To further address the potential utility of this target in human disease, we now demonstrate the presence of a functional Rtt109 orthologue in the clinically relevant fungal pathogen P. jirovecii (i.e., PjRtt109). In a fashion similar to that of Pcrtt109 , Pjrtt109 restores H3K56 acetylation and genotoxic resistance in rtt109 -null yeast. Recombinant PjRtt109 is an active HAT in vitro , with activity comparable to that of PcRtt109 and yeast Rtt109. PjRtt109 HAT activity is also enhanced by the histone chaperone Asf1 in vitro . PjRtt109 and PcRtt109 showed similar low micromolar sensitivities to two reported small-molecule HAT inhibitors in vitro . Together, these results demonstrate that PjRtt109 is a functional Rtt109 HAT, and they support the development of anti- Pneumocystis agents directed at Rtt109-catalyzed histone acetylation as a novel therapeutic target for human PcP.

BACKGROUNDThe authors examined the “real‐world” effectiveness of rituximab (R) maintenance therapy (R‐maintenance) compared with observation after R‐based induction therapy in patients with previously untreated follicular lymphoma (FL) in the United States.METHODSThe National LymphoCare Study is a prospective, multicenter, observational study that enrolled > 2700 untreated patients with FL diagnosed from 2004 to 2007 at 265 sites in the United States. Among these, patients who achieved at least stable disease after R‐based induction therapy were eligible for the current analysis. Patients who initiated R‐maintenance within 215 days of completing induction therapy were categorized as the R‐maintenance group, and those who did not initiate therapy during this period were categorized as the observation group. The objective of the current study was to determine the effect of R‐maintenance on progression‐free survival (PFS), time to next treatment (TTNT), and overall survival (OS).RESULTSA total of 1439 patients completed R‐based induction therapy, 1186 of whom met all inclusion criteria (541 patients received R‐maintenance and 645 patients were observed). Characteristics that were found to be predictive of receiving R‐maintenance were histology grade (1/2), Ann Arbor stage of disease (III/IV), geographic region (region other than the West), and practice setting (community practice). With a median follow‐up of 5.7 years, R‐maintenance was associated with superior PFS (hazards ratio [HR], 0.68; 95% confidence interval [95% CI], 0.56‐0.84 [P = .0003]) and TTNT (HR, 0.66; 95% CI, 0.52‐0.84 [P = .0007]). No significant difference in OS was observed (HR, 0.81; 95% CI, 0.58‐1.14 [P = .23]).CONCLUSIONSR‐maintenance in patients with FL and at least stable disease after R‐based induction therapy provided significantly longer PFS and TTNT in comparison with observation, but no significant difference in OS was observed with 5‐years of follow‐up. This comparative effectiveness study aligns with the results of randomized trials suggesting that similar outcomes occur with R‐maintenance in FL with the treatment variations observed in clinical practice. Cancer 2014;120:1830–1837. © 2014 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.

Significance Cancer cells reprogram their metabolism for optimal growth and survival. AMPK-activated protein kinase (AMPK) is a key energy sensor that controls many metabolic pathways including metabolic reprogramming. However, its role in cancer is poorly understood. Some studies claim that it has a tumor suppressor role while others show its protumor role. Two AMPK-activating compounds (including metformin, now in many clinical trials) are widely used to suppress cancer cell proliferation. We found that AMPK is abundantly expressed in high-grade gliomas and, in contrast to popular belief, these two AMPK activators suppressed glioma cell proliferation through unique AMPK-independent mechanisms.

Background Limited information is available on the frequency of pulmonary embolism ( PE ) in patients with an acute ischemic stroke ( AIS ). We evaluated clinical characteristics, predisposing factors, and outcomes in AIS patients with PE . Methods and Results We included all AIS patients admitted to participating institutions in the R egistry of the C anadian S troke N etwork. Clinically PE was documented by a physician and confirmed by computed tomography pulmonary angiography within 30 days of the stroke case index. The primary outcome was death or disability at discharge. Secondary outcomes included disposition, length of hospital stay, mortality at 3 months and 1 year. Among 11 287 patients with AIS , PE was found in 89 (0.78%) patients. History of cancer, deep vein thrombosis ( DVT )/ PE , and DVT during the hospitalization were associated with PE . PE was associated with higher risk of death at 30 days (25.8% versus 13.6%; P <0.001), at 1 year (47.2% versus 24.6%; P <0.001), and disability at discharge (85.4% versus 63.6%; P <0.001). Mean length of stay was longer in stroke patients with PE (36 versus 16 days; P =0.001). After adjusting for age, sex, and stroke severity, PE remained associated with lower survival at 30 days and 1 year, and death or disability at discharge ( OR 3.02; 95% CI 1.56 to 5.83). Conclusions In this large cohort study, PE occurred in nearly 1% of AIS patients. PE was more common in patients with severe stroke, history of cancer, previous DVT / PE or acute DVT and associated with lower short‐ and long‐term survival, greater disability, and longer length of stay.

By definition, the neurologic impairments of hemiplegic migraine are reversible. However, a few cases of permanent neurologic deficits associated with hemiplegic migraine have been reported. Herein, we present the case of a patient with permanent impairments because of hemiplegic migraine despite normalization of associated brain magnetic resonance imaging abnormalities. Cases like these suggest the need to consider aggressive prophylactic therapy for patients with recurrent hemiplegic migraine attacks.

SummaryPatients with myelofibrosis (MF) have significant debilitating symptoms, physical disabilities, and poor health‐related quality of life (HRQoL). Here, we report post‐hoc analyses of the impact of ruxolitinib, a potent and selective JAK1 and JAK2 inhibitor, on disease‐related symptoms and HRQoL in MF patients from the large phase 3 COMFORT‐II study (N = 219). During the follow‐up period of 48 weeks, HRQoL and MF‐associated symptoms improved from baseline for ruxolitinib‐treated patients but remained the same or worsened for best available therapy (BAT)‐treated patients. Based on the European Organization for Research and Treatment of Cancer QoL Questionnaire core 30 items (EORTC QLQ‐C30), treatment‐induced differences in physical and role functioning, fatigue, and appetite loss significantly favoured ruxolitinib versus BAT from week 8 (P < 0·05) up to week 48 (P < 0·05). Ruxolitinib resulted in significantly higher response rates in global health status/QoL and Functional Assessment of Cancer Therapy‐Lymphoma (FACT‐Lym) summary scores versus BAT at most time points (P < 0·05). Significant improvements in the Lymphoma subscale (including symptoms of pain, fever, itching, fatigue, weight loss, loss of appetite, and other patient concerns), FACT‐General, FACT‐Lym trial outcome index, and FACT‐Lym total were also observed with ruxolitinib versus BAT starting at week 8 and continuing thereafter. Overall, these data demonstrated that ruxolitinib improved HRQoL in MF patients and further support the use of ruxolitinib for the treatment of symptomatic MF.