Mitochondrial injury induced by a Salmonella genotoxin triggers the proinflammatory senescence-associated secretory phenotype

Bacterial genotoxins damage host cells by targeting their chromosomal DNA. In the present study, we demonstrate that a genotoxin of Salmonella Typhi, typhoid toxin, triggers the senescence-associated secretory phenotype (SASP) by damaging mitochondrial DNA. The actions of typhoid toxin disrupt mitochondrial DNA integrity, leading to mitochondrial dysfunction and disturbance of redox homeostasis. Consequently, it facilitates the release of damaged mitochondrial DNA into the cytosol, activating type I interferon via the cGAS-STING pathway. We also reveal that the GCN2-mediated integrated stress response plays a role in the upregulation of inflammatory components depending on the STING signaling axis. These SASP factors can propagate the senescence effect on T cells, leading to senescence in these cells. These findings provide insights into how a bacterial genotoxin targets mitochondria to trigger a proinflammatory SASP, highlighting a potential therapeutic target for an anti-toxin intervention.

INPP5E regulates CD3ζ enrichment at the immune synapse by phosphoinositide distribution control

The immune synapse, a highly organized structure formed at the interface between T lymphocytes and antigen-presenting cells (APCs), is essential for T cell activation and the adaptive immune response. It has been shown that this interface shares similarities with the primary cilium, a sensory organelle in eukaryotic cells, although the roles of ciliary proteins on the immune synapse remain elusive. Here, we find that inositol polyphosphate-5-phosphatase E (INPP5E), a cilium-enriched protein responsible for regulating phosphoinositide localization, is enriched at the immune synapse in Jurkat T-cells during superantigen-mediated conjugation or antibody-mediated crosslinking of TCR complexes, and forms a complex with CD3ζ, ZAP-70, and Lck. Silencing INPP5E in Jurkat T-cells impairs the polarized distribution of CD3ζ at the immune synapse and correlates with a failure of PI(4,5)P2 clearance at the center of the synapse. Moreover, INPP5E silencing decreases proximal TCR signaling, including phosphorylation of CD3ζ and ZAP-70, and ultimately attenuates IL-2 secretion. Our results suggest that INPP5E is a new player in phosphoinositide manipulation at the synapse, controlling the TCR signaling cascade.

Epigenetic remodeling of the immune landscape in cancer: therapeutic hurdles and opportunities

The tumor immune microenvironment represents a sophisticated ecosystem where various immune cell subtypes communicate with cancer cells and stromal cells. The dynamic cellular composition and functional characteristics of the immune landscape along the trajectory of cancer development greatly impact the therapeutic efficacy and clinical outcome in patients receiving systemic antitumor therapy. Mounting evidence has suggested that epigenetic mechanisms are the underpinning of many aspects of antitumor immunity and facilitate immune state transitions during differentiation, activation, inhibition, or dysfunction. Thus, targeting epigenetic modifiers to remodel the immune microenvironment holds great potential as an integral part of anticancer regimens. In this review, we summarize the epigenetic profiles and key epigenetic modifiers in individual immune cell types that define the functional coordinates of tumor permissive and non-permissive immune landscapes. We discuss the immunomodulatory roles of current and prospective epigenetic therapeutic agents, which may open new opportunities in enhancing cancer immunotherapy or overcoming existing therapeutic challenges in the management of cancer.

Phenotypic Correction of Murine Mucopolysaccharidosis Type II by Engraftment of Ex Vivo Lentiviral Vector-Transduced Hematopoietic Stem and Progenitor Cells

Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is an X-linked recessive lysosomal disease caused by deficiency of iduronate-2-sulfatase (IDS). The absence of IDS results in the accumulation of the glycosaminoglycans (GAGs) heparan sulfate and dermatan sulfate. Currently, the only approved treatment option for MPS II is enzyme replacement therapy (ERT), Elaprase. However, ERT is demanding for the patient and does not ameliorate neurological manifestations of the disease. Using an IDS-deficient mouse model that phenocopies the human disease, we evaluated hematopoietic stem and progenitor cells (HSPCs) transduced with a lentiviral vector (LVV) carrying a codon-optimized human IDS coding sequence regulated by a ubiquitous MNDU3 promoter (MNDU3-IDS). Mice treated with MNDU3-IDS LVV-transduced cells showed supraphysiological levels of IDS enzyme activity in plasma, peripheral blood mononuclear cells, and in most analyzed tissues. These enzyme levels were sufficient to normalize GAG storage in analyzed tissues. Importantly, IDS levels in the brains of MNDU3-IDS-engrafted animals were restored to 10-20% than that of wild-type mice, sufficient to normalize GAG content and prevent emergence of cognitive deficit as evaluated by neurobehavioral testing. These results demonstrate the potential effectiveness of ex vivo MNDU3-IDS LVV-transduced HSPCs for treatment of MPS II.

Transforming growth factor-β1 decreases erythropoietin production through repressing hypoxia-inducible factor 2α in erythropoietin-producing cells

BACKGROUND

Renal erythropoietin (EPO)-producing (REP) cells produce EPO through hypoxia-inducible factor (HIF) 2α-activated gene transcription. Insufficient EPO production leads to anemia in patients with chronic kidney disease. Although recombinant EPO is effective to improve anemia, no reliable REP cell lines limit further progress of research and development of novel treatment.

METHODS

We screened Epo mRNA expression in mouse fibroblast cell lines. Small interfering RNA specific for HIF1α or HIF2α was transfected to study Epo expression in C3H10T1/2 cells. The effect of transforming growth factor-β1 (TGF-β1) on HIF-EPO axis was studied in C3H10T1/2 cells and mice.

RESULTS

Similar to mouse REP pericytes, C3H10T1/2 cells differentiated to α-smooth muscle actin⁺ myofibroblasts after exposure to TGF-β1. Specific HIF knockdown demonstrated the role of HIF2α in hypoxia-induced Epo expression. Sustained TGF-β1 exposure increased neither DNA methyltransferase nor methylation of Epas1 and Epo genes. However, TGF-β1 repressed HIF2α-encoding Epas1 promptly through activating activin receptor-like kinase-5 (ALK5), thereby decreasing Epo induction by hypoxia and prolyl hydroxylase domain inhibitor roxadustat. In mice with pro-fibrotic injury induced by ureteral obstruction, upregulation of Tgfb1 was accompanied with downregulation of Epas1 and Epo in injured kidneys and myofibroblasts, which were reversed by ALK5 inhibitor SB431542.

CONCLUSION

C3H10T1/2 cells possessed the property of HIF2α-dependent Epo expression in REP pericytes. TGF-β1 induced not only the transition to myofibroblasts but also a repressive effect on Epas1-Epo axis in C3H10T1/2 cells. The repressive effect of TGF-β1 on Epas1-Epo axis was confirmed in REP pericytes in vivo. Inhibition of TGF-β1-ALK5 signaling might provide a novel treatment to rescue EPO expression in REP pericytes of injured kidney.

NK cell receptor and ligand composition influences the clearance of SARS-CoV-2

To explore how the immune system controls clearance of SARS-CoV-2, we used a single-cell, mass cytometry-based proteomics platform to profile the immune systems of 21 patients who had recovered from SARS-CoV-2 infection without need for admission to an intensive care unit or for mechanical ventilation. We focused on receptors involved in interactions between immune cells and virus-infected cells. We found that the diversity of receptor repertoires on natural killer (NK) cells was negatively correlated with the viral clearance rate. In addition, NK subsets expressing the receptor DNAM1 were increased in patients who more rapidly recovered from infection. Ex vivo functional studies revealed that NK subpopulations with high DNAM1 expression had cytolytic activities in response to target cell stimulation. We also found that SARS-CoV-2 infection induced the expression of CD155 and nectin-4, ligands of DNAM1 and its paired coinhibitory receptor TIGIT, which counterbalanced the cytolytic activities of NK cells. Collectively, our results link the cytolytic immune responses of NK cells to the clearance of SARS-CoV-2 and show that the DNAM1 pathway modulates host-pathogen interactions during SARS-CoV-2 infection.

Peak-Inspiratory-Flow-Rate Guided Inhalation Therapy Reduce Severe Exacerbation of COPD

Optimal peak inspiratory flow rate (PIFR) is crucial for inhalation therapy in patients with chronic obstructive pulmonary disease (COPD). However, little is known about the impact of PIFR-guided inhalation therapy on the clinical outcomes among patients with varying severities of COPD. A PIFR-guided inhalation therapy, including PIFR assessment and PIFR-guided inhaler education, was introduced in a pay-for-performance COPD management program in National Taiwan University Hospital. Among 383 COPD patients, there was significant reduction in incidence of severe acute exacerbation in the PIFR-guided inhalation therapy (PIFR group) than conventional inhaler education (control group) (11.9 vs. 21.1%, p = 0.019) during one-year follow-up. A multivariable Cox’s proportional-hazards analysis revealed that the PIFR-guided inhalation therapy was a significant, independent factor associated with the reduced risk of severe exacerbation (adjusted hazard ratio = 0.49, 95% confidence interval, 0.28–0.84, p = 0.011). Subgroup analysis found PIFR-guided inhalation therapy was more beneficial to patients with older age, short body stature, COPD stage 1&2, group C&D (frequent exacerbation phenotype), and using multiple inhalers. This study showed the PIFR-guided inhalation therapy significantly reduced the incidence of severe acute exacerbation than conventional inhaler education in patients with COPD. Careful PIFR-assessment and education would be crucial in the management of COPD.

Epigenetic modulation of immune synaptic-cytoskeletal networks potentiates γδ T cell-mediated cytotoxicity in lung cancer

γδ T cells are a distinct subgroup of T cells that bridge the innate and adaptive immune system and can attack cancer cells in an MHC-unrestricted manner. Trials of adoptive γδ T cell transfer in solid tumors have had limited success. Here, we show that DNA methyltransferase inhibitors (DNMTis) upregulate surface molecules on cancer cells related to γδ T cell activation using quantitative surface proteomics. DNMTi treatment of human lung cancer potentiates tumor lysis by ex vivo-expanded Vδ1-enriched γδ T cells. Mechanistically, DNMTi enhances immune synapse formation and mediates cytoskeletal reorganization via coordinated alterations of DNA methylation and chromatin accessibility. Genetic depletion of adhesion molecules or pharmacological inhibition of actin polymerization abolishes the potentiating effect of DNMTi. Clinically, the DNMTi-associated cytoskeleton signature stratifies lung cancer patients prognostically. These results support a combinatorial strategy of DNMTis and γδ T cell-based immunotherapy in lung cancer management.

Fucosyltransferase 4 shapes oncogenic glycoproteome to drive metastasis of lung adenocarcinoma

BACKGROUND

Aberrant fucosylation plays a critical role in lung cancer progression. Nevertheless, the key fucosyltransferase with prognostic significance in lung cancer patients, the enzyme's intracellular targets, and complex molecular mechanisms underlying lung cancer metastasis remain incompletely understood.

METHODS

We performed a large-scale transcriptome-clinical correlation to identify major fucosyltransferases with significant prognostic values. Invasion, migration, cell adhesion assays were performed using lung cancer cells subject to genetic manipulation of FUT4 levels. Genome-wide RNA-seq and immunoprecipitation-mass spectrometry were used to characterize major cellular processes driven by FUT4, as well as profiling its intracellular protein targets. We also performed lung homing and metastasis assays in mouse xenograft models to determine in vivo phenotypes of high FUT4-expressing cancer cells.

FINDINGS

We show that FUT4 is associated with poor overall survival in lung adenocarcinoma patients. High FUT4 expression promotes lung cancer invasion, migration, epithelial-to-mesenchymal transition, and cell adhesion. FUT4-mediated aberrant fucosylation markedly activates multiple cellular processes, including membrane trafficking, cell cycle, and major oncogenic signaling pathways. The effects are independent of receptor tyrosine kinase mutations. Notably, genetic depletion of FUT4 or targeting FUT4-driven pathways diminishes lung colonization and distant metastases of lung cancer cells in mouse xenograft models.

INTERPRETATION

We propose that FUT4 can be a prognostic predictor and therapeutic target in lung cancer metastasis. Our data provide a scientific basis for a potential therapeutic strategy using targeted therapy in a subset of patients with high FUT4-expressing tumors with no targetable mutations.

Abstract 583: DNA demethylating agents enhance susceptibility of lung cancer cells to γδ T cell-based immunotherapy via MHC-independent mechanisms

Immune-based therapy is revolutionizing lung cancer management in the clinic. In addition to rejuvenating T cells through immune checkpoint blockade, enhancing the immunogenicity of cancer cells and their interactions with immune cells may also be key to boosting the clinical efficacy of immunotherapy. Previous transcriptomic studies have shown that DNA demethylating agents may alter antigen processing/presentation machinery, upregulate cancer-testis antigens, reactivate endogenous retroviruses to facilitate efficacy of immunotherapy. Nevertheless, how DNA demethylating agents modulate surface immune synapse proteins and affect interactions between cancer and immune cells remain unclear. We utilized stable isotope labeling with amino acids in cell culture (SILAC)-based quantitative membrane proteomics to identify surface proteins altered in decitabine-treated human lung cancer cells. The results showed that decitabine upregulated multiple immune synapse proteins. Gene enrichment analyses discovered that these surface proteins are predominantly involved in γδT cell-mediated cytotoxicity. γδT cells are a distinct subgroup of T cells that bridge between the innate and the adaptive immune systems and do not require the major histocompatibility complexes for antigen recognition. Co-culture of decitabine-pretreated human lung cancer cells with allogenic γδT cells in vitro confirmed sensitization effects of decitabine for the killing of γδT cells. A similar effect was also observed in immunocompromised mice bearing xenograft tumors in vivo. Moreover, the comparison of decitabine-induced surface proteomes between sensitizable and unsensitizable lung cancer cells revealed that intercellular adhesion molecule 1 (ICAM1), was among the top differentially expressed proteins. Imaging analyses confirmed that ICAM1 participated in the formation of immune synapses between cancer cells and γδT cells. Increased expression of ICAM1 was also observed in xenograft tumors from mice receiving combination therapy of decitabine and γδT cells. Overall, our data characterized decitabine-induced surface proteomes and uncovered an immunomodulatory effect of decitabine for enhancing MHC-independent killing by γδT cells. These findings have great clinical implications and provide a novel molecular basis for coupling DNA demethylation agents with γδT cell-based immunotherapy in the treatment of lung cancer patients.

Citation Format: Rueyhung Weng, Chien-Ting Lin, Tai-Chung Huang, Hsuan-Hsuan Lu, Yi-Chieh Wu, Xuan-Hui Lin, Rong-Shan Lin, Chong-Jen Yu, Hsing-Chen Tsai. DNA demethylating agents enhance susceptibility of lung cancer cells to γδ T cell-based immunotherapy via MHC-independent mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 583.

Abstract 1111: Fucosyltransferase 4-mediated aberrant glycosylation and cell signaling networks promote lung cancer metastasis

Rationale:Aberrant glycosylation has been known to regulate cancer cell trafficking via promoting intravascular adhesion during metastasis. Clinicopathological studies have also shown a strong correlation between aberrant glycosylation and invasive/metastatic potentials of human cancers. However, the major glycosylation enzymes that drive lung cancer metastases and the signaling networks involved in the process remain incompletely understood.

Methods:We identified fucosyltransferase 4 (FUT4) as a strong predictor of patient prognosis from two independent cohorts of patients with NSCLC (TCGA and NTUH). We analyzed functional roles of FUT4 through over-expression and knock-down studies using lung cancer cell lines in vitro. Metastatic and homing potentials of FUT4-overexpressed and/or knockdown cells were evaluated in vivo in immunodeficient mice. Genome-wide RNA-seq and MS-based immune-precipitation proteomics were performed to study molecular signaling networks.

Results: High expressions of FUT4 were associated with poor survivals in lung adenocarcinomas (p= 0.000681). FUT4-overexpressed lung cancer cells showed significantly increased migration, invasion, and adhesion abilities in vitro, as well as enhanced homing ability to the lungs in vivo. FUT4-overexpressedcells displayed typical characteristics of epithelial-to-mesenchymal transition (EMT) in a protein level-dependent manner. Lewis X and AAL antigens were significantly up-regulated in FUT4-overexpressedcells, which facilitated binding to E-, L- and P-selections. GSEA of RNA-seq data revealed the enrichment of metastasis-related signaling, especially in EGF and TGF-β signalings. Molecularly, FUT4 enhanced EGFR/TGFBR signaling through glycosylation of TGFBR receptors, which lead to increased binding affinity between ligands and its receptors.

Conclusion: FUT4 promoted metastasis through enhancing mesenchymal phenotype mediated by glycosylated EGFR/TGFBR signaling, and through increasing binding affinity of cancer cells to selectins. High levels of FUT4 in tumor tissues significantly correlate with poor prognosis in NSCLC patients. Our study not only provided new insights into the role of FUT4 on molecular signaling as a potential therapeutic target, but also identified FUT4 as a prognostic marker in NSCLC.

Note: This abstract was not presented at the meeting.

Citation Format: Hsuan-Hsuan Lu, Yi-Hsiu Juan, Rueyhung Roc Weng, Shu-Yung Lin, Yen-Wei Chen, Hsin-Han Hou, Zheng-Ci Hung, Yi-Jhen Huang, Tsai-Yu Yang, Yi-Chieh Wu, Giovanni Audrey Oswita, Jin-Yuan Shih, Hsing-Chen Tsai, Chong-Jen Yu. Fucosyltransferase 4-mediated aberrant glycosylation and cell signaling networks promote lung cancer metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1111.

Rotavirus Gastroenteritis Outbreaks in a neonate intermediate care unit: Direct detection of rotavirus from a computer keyboard and mouse

BACKGROUND

During one week in September, one index case, followed by two cases of rotavirus gastroenteritis infection, was identified in a neonate intermediate care unit of a tertiary teaching children's hospital. An outbreak investigation was launched to clarify the possible infection source and to stop the spread of infection.

METHODS

Cohort care and environmental disinfection were immediately implemented. We screened rotavirus in all the unit neonates' stool samples as well as environmental swab samples. The precautionary measures with regard to hand hygiene and contact isolation taken by healthcare providers and family members were re-examined.

RESULTS

The fourth case was identified 5 days after commencement of the outbreak investigation. There were total 39 contacts, including 6 neonates, 8 family members, and 25 healthcare providers. Nineteen stool samples collected from other neonates in the units revealed one positive case (the fourth case). However, one sample taken from the computer keyboard and mouse in the ward was also positive. The observation of hygiene precautions and the use of isolation gowns by healthcare workers were found to be inadequate. Following the intensification of infection control measures, no further cases of infection were reported.

CONCLUSIONS

Hand hygiene and an intensive isolation strategy remained the most critical precautions for preventing an outbreak of healthcare-associated viral gastroenteritis in the neonate care unit.

Abstract A221: Epigenetic therapy restores polyfunctionality of malignant pleural effusion T-cells in patients with non-small cell lung cancer without downregulation of PD-1

Cytotoxic T-cells in patients with advanced tumors are often dysfunctional due to persistent cancer antigen exposure. These dysfunctional T-cells, known as exhausted T-cells, are characterized by an increased expression of inhibitory receptors and the gradual loss of effector functions, which contribute to immune evasion of cancer cells. Immune checkpoint blockade therapy works by removing the inhibitory signals, reversing the T-cell exhausted state, thereby leading to immune-mediated tumor regression. While immunotherapy has become a front-line treatment for many lung cancer patients for its promising clinical outcome, the durability of this reversal of T-cell exhaustion still remains unsatisfactory, which contributes to eventual treatment failure. Emerging evidence in animal models suggests that exhausted T-cells have a distinct epigenetic landscape that remains unaltered following immune checkpoint blockade therapy. Thus, we hypothesized that epigenetic therapy may reprogram tumor-reactive T-cells to enhance their effector functions. We isolated CD3+ T-cells from malignant pleural effusion or primary tumor tissues of 20 lung cancer patients and examined their immunophenotypes, including surface markers (CD4 and CD8), proliferative index (Ki67), as well as inhibitory receptors (PD-1, TIM3, and CTLA4). T-cells were subject to in vitro daily treatment of decitabine, a DNA methyltransferase inhibitor, for 72 hours. Polyfunctional T-cells that co-express effector functions (i.e., TNF-α, IFN-γ, IL-2 and CD107a) were analyzed by multichromatic flow cytometry. We discovered that T-cells in the malignant pleural effusion or primary lung cancer tissues have higher CD4/CD8 ratios as compared with peripheral blood mononuclear cells from healthy volunteers. The majority of T-cells from lung cancer patients exhibited the exhausted phenotype and expressed at least one inhibitory receptor at higher levels. This indicates that T-cells from malignant pleural effusion could potentially reflect dysfunctional immune states in lung cancer patients when tumor tissues are not available. Moreover, treatment of decitabine at clinically relevant concentrations significantly increased the polyfunctionality of PD-1 positive CD4+ and CD8+ T-cells from selected patients. Interestingly, the reinvigoration of polyfunctional T-cell responses did not associate with the downregulation of PD-1. On the other hand, the effects of decitabine on PD-1 negative CD4+ and CD8+ T-cells were only modest. This suggests that malignant pleural effusion T-cells, which are often PD-1 positive, may respond to epigenetic reprogramming via PD-1-independent mechanisms. Our data shed light on the potential uses of epigenetic therapy in lung cancer treatment by immunomodulation.

Citation Format: Hsing-Chen Tsai, Yi-Chieh Wu, Shu-Yung Lin, I-Yu Chen, Jih-Hsiang Lee, Kuang-Hua Cheng, Ping-Huai Wang, Huan-Jang Ko, Wen-Chien Huang, Yi-Jhen Huang, Kai-Lin Wei, Chong-Jen Yu, Yen-Ling Chiu. Epigenetic therapy restores polyfunctionality of malignant pleural effusion T-cells in patients with non-small cell lung cancer without downregulation of PD-1 [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A221.

Critical threshold levels of DNA methyltransferase 1 are required to maintain DNA methylation across the genome in human cancer cells

Reversing DNA methylation abnormalities and associated gene silencing, through inhibiting DNA methyltransferases (DNMTs) is an important potential cancer therapy paradigm. Maximizing this potential requires defining precisely how these enzymes maintain genome-wide, cancer-specific DNA methylation. To date, there is incomplete understanding of precisely how the three DNMTs, 1, 3A, and 3B, interact for maintaining DNA methylation abnormalities in cancer. By combining genetic and shRNA depletion strategies, we define not only a dominant role for DNA methyltransferase 1 (DNMT1) but also distinct roles of 3A and 3B in genome-wide DNA methylation maintenance. Lowering DNMT1 below a threshold level is required for maximal loss of DNA methylation at all genomic regions, including gene body and enhancer regions, and for maximally reversing abnormal promoter DNA hypermethylation and associated gene silencing to reexpress key genes. It is difficult to reach this threshold with patient-tolerable doses of current DNMT inhibitors (DNMTIs). We show that new approaches, like decreasing the DNMT targeting protein, UHRF1, can augment the DNA demethylation capacities of existing DNA methylation inhibitors for fully realizing their therapeutic potential.

Epigenetic silencing of neurofilament genes promotes an aggressive phenotype in breast cancer

Neurofilament heavy polypeptide (NEFH) has recently been identified as a candidate DNA hypermethylated gene within the functional breast cancer hypermethylome. NEFH exists in a complex with neurofilament medium polypeptide (NEFM) and neurofilament light polypeptide (NEFL) to form neurofilaments, which are structural components of the cytoskeleton in mature neurons. Recent studies reported the deregulation of these proteins in several malignancies, suggesting that neurofilaments may have a role in other cell types as well. Using a comprehensive approach, we studied the epigenetic inactivation of neurofilament genes in breast cancer and the functional significance of this event. We report that DNA methylation-associated silencing of NEFH, NEFL, and NEFM in breast cancer is frequent, cancer-specific, and correlates with clinical features of disease progression. DNA methylation-mediated inactivation of these genes occurs also in multiple other cancer histologies including pancreas, gastric, and colon. Restoration of NEFH function, the major subunit of the neurofilament complex, reduces proliferation and growth of breast cancer cells and arrests them in Go/G1 phase of the cell cycle along with a reduction in migration and invasion. These findings suggest that DNA methylation-mediated silencing of the neurofilament genes NEFH, NEFM, and NEFL are frequent events that may contribute to the progression of breast cancer and possibly other malignancies.

Abstract B27: Epigenetic regulation of stem cell fate in leukemic subpopulations

Leukemia often displays substantial intratumor heterogeneity, comprising subpopulations of cells with different self-renewing and leukemia initiation capacities. Epigenetic mechanisms have been implicated in stem cell fate regulation during normal hematopoiesis. Although aberrant epigenetic changes have been well documented in hematological malignancies, the role epigenetic mechanisms play in governing stem-like properties, such as leukemia initiating capacity, and possible cell fate transitions between stem-like and non-stem-like leukemia subpopulations is unclear. Using next-generation sequencing and microarray technologies, we conducted an integrated analysis of DNA methylation, histone modifications and transcriptional profiles to investigate the epigenomic differences between experimentally characterized CD34-positive (CD34pos) leukemia-initiating and CD34-negative (CD34neg) non-leukemia-initiating subpopulations in a human acute myelogenous leukemia (AML) cell line. We demonstrated that multiple normal and leukemic stem cell gene signatures are significantly enriched in CD34pos leukemia initiating cells as opposed to CD34neg AML cells. We also observed concordant chromatin state transitions at the promoters of stem cell signature genes. The stem-like state of CD34pos leukemia initiating cells is also characterized by a number of genes with bivalent histone modifications at their promoters. Many genes undergoing bivalent domain resolution and transcriptional activation in CD34neg AML cells are involved in differentiation-related pathways. Most importantly, epigenomic analysis showed that treatment with epigenetic modifying agents, such as 5-aza-2'-deoxycytidine, appeared to facilitate cell fate transitions, induce marked changes in chromatin configurations, and reverse the enrichments of stem cell signatures in CD34pos leukemia-initiating cells. This provides an important molecular basis for the diminished in vitro clonogenecity and in vivo leukemogenecity of AML cells after 5-aza-2'-deoxycytidine treatment in our previous studies. Our data supports the important role of epigenetic mechanisms in underpinning cell fate and functional properties of leukemia subpopulations. The epigenetic regulation of leukemic stem-like properties might differ from that of normal hematopoietic stem cell state since the same 5-aza-2'-deoxycytidine treatment did not seem to negatively affect clonogenecity of normal hematopoietic cells. Understanding the dynamics of epigenetic state transitions between leukemia subpopulations may offer novel targets for leukemia treatment, and facilitate development of epigenetic therapy targeting leukemia initiating cells.

Citation Format: Hsing-Chen Tsai, Hariharan Easwaran, Stephen B. Baylin. Epigenetic regulation of stem cell fate in leukemic subpopulations. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr B27.

Optogenetics in Freely Moving Mammals: Dopamine and Reward

Brain reward systems play a central role in the cognitive and hedonic behaviors of mammals. Multiple neuron types and brain regions are involved in reward processing, posing fascinating scientific questions, and major experimental challenges. Using diverse approaches including genetics, electrophysiology, imaging, and behavioral analysis, a large body of research has focused on both normal functioning of the reward circuitry and on its potential significance in neuropsychiatric diseases. In this introduction, we illustrate a real-world application of optogenetics to mammalian behavior and physiology, delineating procedures and technologies for optogenetic control of individual components of the reward circuitry. We describe the experimental setup and protocol for integrating optogenetic modulation of dopamine neurons with fast-scan cyclic voltammetry, conditioned place preference, and operant conditioning to assess the causal role of well-defined electrical and biochemical signals in reward-related behavior.

Quantifying midbrain serotonin transporter in depression: a preliminary study of diagnosis and naturalistic treatment outcome

INTRODUCTION

Serotonin may play an important role in the pathology of major depressive disorder (MDD). However, the relationship between serotonin transporter (SERT) availability and the medical outcome of antidepressant treatment is uncertain.

METHODS

In this naturalistic study, SERT availability (expressed as the specific uptake ratio, SUR) in the midbrain of 17 drug-free patients with MDD and 17 controls matched for age and gender was measured using SPECT with [(123)I]ADAM. The severity of MDD was measured by the Hamilton Depression Rating Scale before, and after 6 weeks of non-standardized antidepressant treatment.

RESULTS

A total of 12 patients completed the study. The SUR of the patients with MDD was significantly lower than that of the healthy controls. The SUR of SERT was not found to have a linear relationship with the treatment outcome; however, supplemental analysis found a curvilinear relationship between treatment outcome and the SUR of SERT.

DISCUSSION

The findings indicate that the SUR of SERT is lower in patients with MDD; however it did not predict treatment outcome in a linear fashion. Studies with larger sample sizes are required.

Central venous catheter-associated bloodstream infections in pediatric hematology-oncology patients and effectiveness of antimicrobial lock therapy

BACKGROUND

Central line-associated bloodstream infection (CLABSI) is a serious complication in hematology-oncology patients. This study aimed to analyze the prevalence of CLABSI and the effectiveness of antimicrobial lock therapy (ALT) in pediatric patients.

METHODS

BSIs of all pediatric hematology-oncology patients admitted to a children's hospital between January 2009 and December 2013 were reviewed. The United States National Healthcare Safety Network and Infectious Diseases Society of America guidelines were used to define CLABSI and catheter-related BSI (CRBSI). The incidence, laboratory and microbiology characteristics, poor outcome, and effectiveness of ALT were analyzed.

RESULTS

There were 246 cases of CLABSI in 146 patients (mean age, 10.0 years), including 66 (26.8%) cases of CRBSI. The incidence of CLABSI was 4.49/1000 catheter-days, and the infection was responsible for 32.9% of the complications these patients developed and 9.3% of contributable mortality. Patients with acute myeloid leukemia had the highest infection density (5.36/1000 patient-days). Enterobacteriaceae (40.2%) and coagulase-negative staphylococci (CoNS; 20.7%) were the predominant pathogens. In multivariate analysis, older age, male sex, elevated C-reactive protein, acute lymphoblastic leukemia, and candidemia were associated with poor outcome. The success rate of ALT was 58.6% (17/29) for the treatment of CoNS and 78.3% (29/37) for Enterobacteriaceae infections. Patients with candidemia (n = 18) had the highest mortality (33.4%) and catheter removal rate (66.7%). Chlorhexidine as the disinfectant decreased the 1-year CLABSI rate from 13.7/1000 to 8.4/1000 catheter-days (p = 0.02).

CONCLUSION

CoNS and Enterobacteriaceae are the predominant pathogens in CLABSI among pediatric hematology-oncology patients. ALT is effective and showed no significant side effect. New disinfection practice and infection control measures can decrease CLABSI.

Transmission of acute infectious illness among cases of Kawasaki disease and their household members

BACKGROUND/PURPOSE

Kawasaki disease (KD) is a disease of unknown cause and the causative agent is most likely to be infectious in nature. To investigate the household transmission pattern of infectious illness and etiology, we thus initiated a prospective case and household study.

METHODS

We enrolled KD cases and their household members from February 2004 to September 2008. The KD cases and their household members accepted questionnaire-based interviews of the contact history, signs of infection, and symptoms to check whether clusters of infectious illness occurred.

RESULTS

A total of 142 KD cases and 561 household members were enrolled. Among the 142 KD cases, 136 cases (96%) were typical KD, and six (4%) were atypical KD. Of the 561 household members, 17% were siblings, 46% were parents, 18% were grandparents, and the others were cousins or babysitters. Prior to the onset of their KD illness, 66% (94/142) KD cases had contact with ill household members. On the same day of the onset of KD cases' illness, 4% (6/142) KD cases had household members with illness. After KD cases' disease onset, 70% (100/142) KD cases had at least one other family member with illness. Overall, 61% (343/561) of all the household members had acute infectious illness during KD cases' acute stage, and 92% (130/142) of the families had clusters of infectious illness.

CONCLUSION

A total of 66% KD cases had positive contact with ill household members prior to their disease onset and 92% of families had clusters of infectious illness, so KD is strongly associated with infections.

Cancer epigenetics: tumor heterogeneity, plasticity of stem-like states, and drug resistance

The existence of subpopulations of cells in cancers with increased tumor-initiating capacities and self-renewal potential, often termed "cancer stem cells," is a much discussed and key area of cancer biology. Such cellular heterogeneity is very important because of its impact on therapy and especially states of treatment resistance. A major question is whether there is plasticity for evolution of these cell states during tumorigenesis that can involve movement between cell populations in a reversible fashion. In this review, we discuss the possible role of epigenetic abnormalities as well as genetic alterations in such dynamics and in the creation of cellular heterogeneity in cancers of all types.

Dopamine neurons modulate neural encoding and expression of depression-related behaviour

Major depression is characterized by diverse debilitating symptoms that include hopelessness and anhedonia. Dopamine neurons involved in reward and motivation are among many neural populations that have been hypothesized to be relevant, and certain antidepressant treatments, including medications and brain stimulation therapies, can influence the complex dopamine system. Until now it has not been possible to test this hypothesis directly, even in animal models, as existing therapeutic interventions are unable to specifically target dopamine neurons. Here we investigated directly the causal contributions of defined dopamine neurons to multidimensional depression-like phenotypes induced by chronic mild stress, by integrating behavioural, pharmacological, optogenetic and electrophysiological methods in freely moving rodents. We found that bidirectional control (inhibition or excitation) of specified midbrain dopamine neurons immediately and bidirectionally modulates (induces or relieves) multiple independent depression symptoms caused by chronic stress. By probing the circuit implementation of these effects, we observed that optogenetic recruitment of these dopamine neurons potently alters the neural encoding of depression-related behaviours in the downstream nucleus accumbens of freely moving rodents, suggesting that processes affecting depression symptoms may involve alterations in the neural encoding of action in limbic circuitry.

Optimal treatment for asymptomatic neurosyphilis

In the pre-penicillin era, patients with asymptomatic neurosyphilis (ANS) were more likely to develop long-term neurological sequelae than those patients with normal cerebrospinal fluid (CSF). Although benzathine penicillin G cannot achieve treponemicidal levels in the CSF, decreased rates of neurological complications of syphilis and non-treponemal titre serological responses are usually observed after treatment with this antibiotic. We here a homosexual man with ANS successfully treated with benzathine penicillin G. This case suggests that reconsideration on the necessity of a lumbar puncture in HIV-infected patients with ANS is warranted.

Abstract 995: Transient low doses of DNA demethylating agents exert durable antitumor effects on hematological and epithelial tumor cells

Reversal of gene promoter DNA hypermethylation and associated abnormal gene silencing is an attractive approach to cancer therapy. The DNA methylation inhibitors, decitabine (5-aza-2′-deoxycytidine) and azacitidine (5-azacytidine) are proving efficacious clinically for hematological neoplasms, especially at lower, less toxic, doses. Experimentally, high doses induce rapid DNA damage and cytotoxicity, but these may not explain the prolonged time to response often seen in patients. We now show that transient exposure of cultured and primary leukemic and epithelial tumor cells to decitabine or azacitidine at clinically-relevant nanomolar doses, without causing immediate cytotoxicity, produces a “memory” for anti-tumor responses, including potent inhibition of subpopulations of cancer, stem-like cells which often resist other therapies. These inhibitory effects are accompanied by sustained decreases in genome-wide promoter DNA methylation with associated gene re-expression, and anti-tumor changes in multiple key cellular regulatory pathways, such as cell cycle events mediated through FOXM1, cell invasion and motility, and granulocyte and breast cancer cell maturation. Notably, most of the key pathways altered by decitabine or azacitidine involve high priority targets for pharmacologic anti-cancer strategies, which provides molecular basis for possible combination therapies. Thus, low dose decitabine and azacitidine regimens may potentially have broad applicability for cancer management.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 995. doi:1538-7445.AM2012-995

Transient low doses of DNA-demethylating agents exert durable antitumor effects on hematological and epithelial tumor cells

Reversal of promoter DNA hypermethylation and associated gene silencing is an attractive cancer therapy approach. The DNA methylation inhibitors decitabine and azacitidine are efficacious for hematological neoplasms at lower, less toxic, doses. Experimentally, high doses induce rapid DNA damage and cytotoxicity, which do not explain the prolonged time to response observed in patients. We show that transient exposure of cultured and primary leukemic and epithelial tumor cells to clinically relevant nanomolar doses, without causing immediate cytotoxicity, produce an antitumor "memory" response, including inhibition of subpopulations of cancer stem-like cells. These effects are accompanied by sustained decreases in genomewide promoter DNA methylation, gene reexpression, and antitumor changes in key cellular regulatory pathways. Low-dose decitabine and azacitidine may have broad applicability for cancer management.

Tracking stem cell differentiation in the setting of automated optogenetic stimulation

Membrane depolarization has been shown to play an important role in the neural differentiation of stem cells and in the survival and function of mature neurons. Here, we introduce a microbial opsin into ESCs and develop optogenetic technology for stem cell engineering applications, with an automated system for noninvasive modulation of ESC differentiation employing fast optogenetic control of ion flux. Mouse ESCs were stably transduced with channelrhodopsin-2 (ChR2)-yellow fluorescent protein and purified by fluorescence activated cell sorting (FACS). Illumination of resulting ChR2-ESCs with pulses of blue light triggered inward currents. These labeled ESCs retained the capability to differentiate into functional mature neurons, assessed by the presence of voltage-gated sodium currents, action potentials, fast excitatory synaptic transmission, and expression of mature neuronal proteins and neuronal morphology. We designed and tested an apparatus for optically stimulating ChR2-ESCs during chronic neuronal differentiation, with high-speed optical switching on a custom robotic stage with environmental chamber for automated stimulation and imaging over days, with tracking for increased expression of neural and neuronal markers. These data point to potential uses of ChR2 technology for chronic and temporally precise noninvasive optical control of ESCs both in vitro and in vivo, ranging from noninvasive control of stem cell differentiation to causal assessment of the specific contribution of transplanted cells to tissue and network function.

Cancer epigenetics: linking basic biology to clinical medicine

Cancer evolution at all stages is driven by both epigenetic abnormalities as well as genetic alterations. Dysregulation of epigenetic control events may lead to abnormal patterns of DNA methylation and chromatin configurations, both of which are critical contributors to the pathogenesis of cancer. These epigenetic abnormalities are set and maintained by multiple protein complexes and the interplay between their individual components including DNA methylation machinery, histone modifiers, particularly, polycomb (PcG) proteins, and chromatin remodeling proteins. Recent advances in genome-wide technology have revealed that the involvement of these dysregulated epigenetic components appears to be extensive. Moreover, there is a growing connection between epigenetic abnormalities in cancer and concepts concerning stem-like cell subpopulations as a driving force for cancer. Emerging data suggest that aspects of the epigenetic landscape inherent to normal embryonic and adult stem/progenitor cells may help foster, under the stress of chronic inflammation or accumulating reactive oxygen species, evolution of malignant subpopulations. Finally, understanding molecular mechanisms involved in initiation and maintenance of epigenetic abnormalities in all types of cancer has great potential for translational purposes. This is already evident for epigenetic biomarker development, and for pharmacological targeting aimed at reversing cancer-specific epigenetic alterations.

Abstract LB-88: Transient exposure to low-dose decitabine and azacytidine reprograms cancer cells to produce a prolonged antitumor response

Reversing abnormal promoter DNA hypermethylation to induce expression of abnormally silenced genes is an attractive cancer therapeutic strategy. The DNA methylation inhibitors, decitabine (5-aza-2′-deoxycytidine) and azacytidine (5-azacytidine), have proven clinically effective against hematological neoplasms especially with use of low, minimally toxic, doses. While, experimentally, high doses of these drugs induce DNA damage and cytotoxicity, the prolonged time for patient responses does not suggest acute tumor cell lysis. We now separate, for these drugs, cytotoxic effects at high doses from cellular reprogramming effects at low nanomolar doses. These latter subsequently reduce tumorigenicity of human leukemia and solid tumor cells, and for leukemia cells, blunt long term self-renewal. We correlate these effects with sustained, genome wide, promoter DNA de-methylation and gene re-expression, and an anti-tumor reprogramming of multiple central cancer pathways which regulate cell cycle entry, mitosis, proliferation, apoptosis, and dependence upon anaerobic glycolysis. Thus, decitabine and azacytidine represent drugs that can, at low nanomolar doses, simultaneously reverse major cancer pathways each of which are the focus of intense drug targeting efforts. This suggests these drugs are broadly applicable to cancer management.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-88.

Progressive chromatin repression and promoter methylation of CTNNA1 associated with advanced myeloid malignancies

Complete loss or deletion of the long arm of chromosome 5 is frequent in myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). The putative gene(s) deleted and responsible for the pathogenesis of these poor prognosis hematologic disorders remain controversial. This study is a comprehensive analysis of previously implicated and novel genes for epigenetic inactivation in AML and MDS. In 146 AML cases, methylation of CTNNA1 was frequent, and more common in AML patients with 5q deletion (31%) than those without 5q deletion (14%), whereas no methylation of other 5q genes was observed. In 31 MDS cases, CTNNA1 methylation was only found in high-risk MDS (>or=RAEB2), but not in low-risk MDS (<RAEB2), indicating that CTNNA1 methylation might be important in the transformation of MDS to AML. CTNNA1 expression was lowest in AML/MDS patients with CTNNA1 methylation, although reduced expression was found in some patients without promoter methylation. Repressive chromatin marks (H3K27me3) at the promoter were identified in CTNNA1-repressed AML cell lines and primary leukemias, with the most repressive state correlating with DNA methylation. These results suggest progressive, acquired epigenetic inactivation at CTNNA1, including histone modifications and promoter CpG methylation, as a component of leukemia progression in patients with both 5q- and non-5q- myeloid malignancies.

Heparin-induced thrombocytopenia associated with intra-tumour haemorrhage in cavernous sinus after cardiac myxoma surgery

Heparin-induced thrombocytopenia (HIT) is a life-threatening disorder that is associated with heparin exposure. The incidence of HIT in patients undergoing cardiac surgery is relatively rare. We present a case of intratumor haemorrhage in the cavernous sinus 1 week after cardiac surgery. The pathogenesis may be venous thrombosis and haemorrhagic infarct caused by HIT following cardiopulmonary bypass surgery. This is a rare case and has not been reported previously.

Phasic firing in dopaminergic neurons is sufficient for behavioral conditioning

Natural rewards and drugs of abuse can alter dopamine signaling, and ventral tegmental area (VTA) dopaminergic neurons are known to fire action potentials tonically or phasically under different behavioral conditions. However, without technology to control specific neurons with appropriate temporal precision in freely behaving mammals, the causal role of these action potential patterns in driving behavioral changes has been unclear. We used optogenetic tools to selectively stimulate VTA dopaminergic neuron action potential firing in freely behaving mammals. We found that phasic activation of these neurons was sufficient to drive behavioral conditioning and elicited dopamine transients with magnitudes not achieved by longer, lower-frequency spiking. These results demonstrate that phasic dopaminergic activity is sufficient to mediate mammalian behavioral conditioning.

Abnormal DNA methylation of CD133 in colorectal and glioblastoma tumors

Much recent effort has focused on identifying and characterizing cellular markers that distinguish tumor propagating cells (TPC) from more differentiated progeny. We report here an unusual promoter DNA methylation pattern for one such marker, the cell surface antigen CD133 (Prominin 1). This protein has been extensively used to enrich putative cancer propagating stem-like cell populations in epithelial tumors and, especially, glioblastomas. We find that, within individual cell lines of cultured colon cancers and glioblastomas, the promoter CpG island of CD133 is DNA methylated, primarily, in cells with absent or low expression of the marker protein, whereas lack of such methylation is evident in purely CD133+ cells. Differential histone modification marks of active versus repressed genes accompany these DNA methylation changes. This heterogeneous CpG island DNA methylation status in the tumors is unusual in that other DNA hypermethylated genes tested in such cultures preserve their methylation patterns between separated CD133+ and CD133- cell populations. Furthermore, the CD133 DNA methylation seems to constitute an abnormal promoter signature because it is not found in normal brain and colon but only in cultured and primary tumors. Thus, the DNA methylation is imposed on the transition between the active versus repressed transcription state for CD133 only in tumors. Our findings provide additional insight for the dynamics of aberrant DNA methylation associated with aberrant gene silencing in human tumors.

Fever of Unknown Origin in Taiwan

BACKGROUND

Fever of unknown origin (FUO) is a challenging problem worldwide. There was no prospective study of FUO in the past two decades in Taiwan. A prospective study was conducted.

MATERIALS AND METHODS

The prospective study was undertaken from March 2001 to May 2002. All patients fulfilling the modified criteria for FUO, either admitted, referred or consulted in a medical center in southern Taiwan, were enrolled for analysis.

RESULTS

A total of 94 cases met the criteria of FUO. The final diagnoses of FUO consisted of 54 infectious diseases (57.4%), 8 hematologic/neoplastic (8.5%), 7 noninfectious inflammatory (7.4%), 8 miscellaneous (8.5%) and 17 undiagnosed (18.1%) cases. The single most common cause of FUO was tuberculosis. Some infectious diseases, such as rickettsiosis and melioidosis, were rarely reported in western countries. Three patients with hemophagocytotic syndrome without ascertainable etiologies were present with FUO in this study. Between the patients with and those without a final diagnosis, the short-term survival (3 months) was compared by the Kaplan-Meier analysis, which revealed no difference.

CONCLUSIONS

Mycobacteriosis is still the leading cause of FUO in Taiwan and it is important to identify this treatable disease from all causes of FUO. This study has showed geographical variation among the studies of FUO.

Stromal cell-derived inducing activity, Nurr1, and signaling molecules synergistically induce dopaminergic neurons from mouse embryonic stem cells

To induce differentiation of embryonic stem cells (ESCs) into specialized cell types for therapeutic purposes, it may be desirable to combine genetic manipulation and appropriate differentiation signals. We studied the induction of dopaminergic (DA) neurons from mouse ESCs by overexpressing the transcription factor Nurr1 and coculturing with PA6 stromal cells. Nurr1-expressing ESCs (N2 and N5) differentiated into a higher number of neurons (approximately twofold) than the naïve ESCs (D3). In addition, N2/N5-derived cells contained a significantly higher proportion (>50%) of tyrosine hydroxylase (TH)+ neurons than D3 (<30%) and an even greater proportion of TH+ neurons (approximately 90%) when treated with the signaling molecules sonic hedgehog, fibroblast growth factor 8, and ascorbic acid. N2/N5-derived cells express much higher levels of DA markers (e.g., TH, dopamine transporter, aromatic amino acid decarboxylase, and G protein-regulated inwardly rectifying K+ channel 2) and produce and release a higher level of dopamine, compared with D3-derived cells. Furthermore, the majority of generated neurons exhibited electrophysiological properties characteristic of midbrain DA neurons. Finally, transplantation experiments showed efficient in vivo integration/generation of TH+ neurons after implantation into mouse striatum. Taken together, our results show that the combination of genetic manipulation(s) and in vitro cell differentiation conditions offers a reliable and effective induction of DA neurons from ESCs and may pave the way for future cell transplantation therapy in Parkinson's disease.

Induction of inducible nitric oxide synthase by Epstein-Barr virus B95-8-derived LMP1 in Balb/3T3 cells promotes stress-induced cell death and impairs LMP1-mediated transformation

The latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV) causes cellular transformation and activation of several intracellular signaling events. In this report, we show that BLMP1 (encoded by the LMP1 gene derived from the B95-8 strain of EBV) triggers the expression of inducible nitric oxide synthase (iNOS) in Balb/3T3 fibroblasts. Intriguingly, NLMP1, a natural sequence variant of LMP1 identified in EBV-positive nasopharyngeal carcinoma biopsy, does not similarly induce iNOS expression. BLMP1-induced iNOS in Balb/3T3 cells is active to produce nitric oxide (NO), and NO production can be blocked by several iNOS inhibitors. When subjected to environmental stress, Balb/3T3 cells that produce NO lose viability more rapidly than non NO-producing cells. Blockage of NO generation by iNOS inhibitors enhances the viability of NO-producing cells under stress conditions. The activities of caspase-3 and c-Jun N-terminal kinase, two important regulators mediating stress-induced apoptosis, are significantly potentiated following heat shock treatment of BLMP1-expressing/NO-producing cells, compared to parental and NLMP1-expressing cells. Furthermore, treatment with iNOS inhibitor augmented the cloning efficiency (in culture) and tumor growth (in nude mice) of BLMP1-expressing/NO-producing cells. Collectively, the results demonstrate that BLMP1 induces iNOS expression and NO production in Balb/3T3 cells, which leads to the alteration of cell functions, including sensitivity to environmental stress, capability to colonize independent of anchorage and tumorigenicity in nude mice. Our data additionally implicate that the differential iNOS induction potential of the two LMP1 forms may represent the basis of a functional difference between the two LMP1 proteins.

Association between cytomegalovirus-specific reactivity of T cell subsets and development of cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome

The association between cytomegalovirus (CMV)-specific reactivity of T cell subsets and development of CMV retinitis (CMV-R) was prospectively studied in 50 CMV-seropositive AIDS patients. The frequency of CMV-specific CD69 expression on CD8 T cells was similar in patients with and patients without CMV-R (median, 1.0% vs. 1.2%; P=.14). However, the frequency of CMV-specific CD69 expression on CD4 T cells was significantly lower in patients with CMV-R than in those without CMV-R (median, 0.4% vs. 2.25%; P<.001). CMV-specific CD4 T cell reactivity in patients who developed CMV-R shortly after starting highly active antiretroviral therapy (HAART) remained low, although the CD4 cell counts increased markedly. Therefore, development of CMV-R is associated with a poor CMV-specific reactivity of CD4 T cells but not with poor reactivity of CD8 T cells. Development of CMV-R after initiation of HAART is associated with a poor reconstitution of CMV-specific immune response, rather than with immune rebound.

Kinetics of antigen-induced phenotypic and functional maturation of human monocyte-derived dendritic cells

Dendritic cells (DCs), a critical component of innate immunity, are the most potent APCs. When DCs mature, they can elicit strong T cell responses. We studied the kinetics of Ag-induced phenotypic and functional maturation of human monocyte-derived DCs using an in vitro T cell-independent culture system. With this model, we herein show that an Ag that has recently or repetitively been exposed ("exposed Ag") rapidly induces a high level of maturation; however, an Ag that has never or only remotely been exposed ("unexposed Ag") slowly induces a low level of maturation. The kinetics of Ag-induced maturation of DCs possibly implies a novel mechanism for immunological memory that would provide maximal host protection from repetitively invading pathogens in the environment.

Pneumocystis carinii pneumonia in systemic lupus erythematosus: a report of two cases

Patients with systemic lupus erythematosus (SLE) have increased susceptibility to infection by Pneumocystis carinii, but this condition has rarely been reported in Taiwan. Here, we describe two cases of patients with SLE who developed Pneumocystis carinii pneumonia (PCP). The first patient was a 39-year-old woman presenting with fever and dyspnea that had lasted 2 weeks. Chest roentgenography disclosed bilateral interstitial and alveolar infiltrates. The second patient was a 22-year-old woman presenting with a 4-day history of malaise, cough, dyspnea, and fever. She had concomitant Mycobacterium tuberculosis infection. Both patients had been treated with varying doses of corticosteroids and/or cytotoxic drugs within 4 months before presentation. Diagnosis was established based on the findings of bronchoalveolar lavage (BAL) and transbronchial lung biopsy (TBLB). Both patients received trimethoprim-sulfamethoxazole (20 mg.kg-1.d-1 trimethoprim), but finally died of nosocomial septicemia (Acinetobacter baumanni and Pseudomonas aeruginosa bacteremia in one, P. aeruginosa bacteremia in the other). These two cases demonstrate that PCP should be included in the differential diagnosis of patients with SLE presenting with pneumonic processes. In addition, a second opportunistic pathogen should be suspected. Bronchoscopic examination should be performed if the diagnosis is not clear and should include TBLB and BAL.

Eosinophilic meningitis caused by Angiostrongylus cantonensis: report of 17 cases

PURPOSE

To describe two outbreaks of Angiostrongylus cantonensis infection that occurred in Kaohsiung, Taiwan, during 1998 and 1999, and to characterize the source of the outbreaks and the clinical manifestations of the disease.

SUBJECTS AND METHODS

We performed a retrospective cohort study among Thai laborers with eosinophilic meningitis who ate raw snails (Ampullarium canaliculatus), as well as an environmental surveillance of larvae in snails.

RESULTS

We enrolled 17 Thai laborers in whom severe headache and eosinophilia developed within 4 to 23 days after eating raw snails. Twelve (71%) developed eosinophilic meningitis. Third-stage larvae were found in the cerebrospinal fluids of 2 patients and in all 12 tested snails. Specific antibodies to A. cantonensis were detected in serum from 16 of the patients and in cerebrospinal fluid from 5 of the patients. Central nervous system manifestations included headache (n = 17 [100%]), fever (n = 11 [65%]), Brudzinski's sign/stiff neck (n = 11 [65%]), hyperesthesia (n = 3 [18%]), cranial nerve palsy (n = 2 [12%]), diplopia (n = 2 [12%]), and ataxia (n = 1 [6%]). Laboratory findings included peripheral eosinophilia (n = 15 [88%]) and cerebrospinal fluid eosinophilia (n = 12 [71%]); elevated immunoglobulin (Ig) E levels (n = 13 [100%]); and transient increases in white blood cell count (n = 7 [41%]) and in serum levels of creatine kinase (n = 7 [41%]), transaminase (n = 3 [18%]), and lactate dehydrogenase (n = 2 [12%]). The severity of illness and eosinophilia were correlated with the number of ingested snails. Meningeal and basal ganglion enhancement was noted on magnetic resonance imaging in several patients. Treatment with mebendazole combined with glucocorticosteroids appeared to shorten the course of the infection, but not the number of relapses. The eosinophil count fell to normal within 3 months, but IgE levels remained elevated for as long as 6 months. All patients recovered with minimal neurologic sequelae.

CONCLUSION

Eosinophilic meningitis caused by A. cantonensis should be considered in patients who have headache or central nervous system manifestations after eating raw snails.

Diabetic ketoacidosis and hypogonadotropic hypogonadism in association with transfusional hemochromatosis in a man with beta-thalassemia major

We report a 23-year-old man with beta-thalassemia major and transfusional hemochromatosis, which manifested as diabetic ketoacidosis and hypogonadotropic hypogonadism. This unusual presentation of diabetic ketoacidosis in hemochromatosis has rarely been reported. Magnetic resonance imaging of the abdomen showed decreased signal intensity in the liver, spleen, and pancreas. In addition, the pituitary gland also showed heterogeneous low signal intensity, compatible with hemochromatosis. He was treated with insulin supplements and pulsatile human chorionic gonadotropin administration. Clinical improvement was noted after hormone replacement. Intensive iron chelation therapy was given to prevent cardiac complications, and to restore his gonadal function. During follow-up, the patient experienced improvement in libido and sexual potency.

Comparative study of the efficacy and safety of valaciclovir versus acyclovir in the treatment of herpes zoster

Acyclovir, a specific and selective inhibitor of the replication of Herpesviridae family, has well-documented efficacy and tolerability in the treatment of herpes zoster. Its limited oral bioavailability and short half-life, however, necessitates frequent dosing. Valaciclovir, the l-valyl ester of acyclovir, could be rapidly converted to acyclovir after oral administration, resulting in a three- to five-fold increase in acyclovir bioavailability compared with oral acyclovir in humans. Valaciclovir allows less frequent dosing and maintains the safety profiles of the parent drug. During the period from October 1996 through May 1998, a randomized, prospective study was performed in the Kaohsiung Veterans General Hospital to compare the safety and efficacy of valaciclovir with acyclovir in the treatment of herpes zoster in Taiwanese patients. Patients presenting with herpes zoster within 72 h after the onset of rash were enrolled and randomized to receive one of the following treatments: 1000 mg valaciclovir three times daily for 7 days or acyclovir 800 mg five times daily for 7 days. Patients were followed up for 29 days beginning with the start of therapy. A total of 57 patients were enrolled and randomized to receive valaciclovir (n = 32) or acyclovir (n = 25). Five patients in the valaciclovir group and three in the acyclovir group did not complete the study. The intent-to-treat analysis (57 patients) showed that valaciclovir significantly accelerated the resolution of herpes zoster-associated pain compared with acyclovir; on day 29, the valaciclovir group was 23% superior to the acyclovir group. There was no clinically significant difference in the nature, frequency or severity of adverse events between these two groups, although one and three adverse events were reported in the acyclovir and valaciclovir group, respectively. Thus, we conclude that in the management of herpes zoster, valaciclovir accelerates the resolution of pain and offers a simpler dosing, and maintains the favorable safety profile of acyclovir.

Legionnaires' disease in an immunocompetent young adult

Infection with Legionella pneumophila (LP) is a rare cause of pneumonia in previously healthy young adults. Pleural effusion is relatively common in Legionnaires' disease but is usually clinically insignificant. Herein we describe an immunocompetent, 19-year-old female with LP respiratory infection that presented with pleural effusion and mild interstitial infiltrates in the lower lungs. She received 3 weeks' treatment with erythromycin and rifampin and recovered completely. Diagnosis was based on serology testing with a four-fold rise of the antibody titer in the acute and convalescent phase. Legionnaires' disease should be considered in the differential diagnosis of culture-negative pleural effusion in immunocompetent young adults.

Restoration of cellular immunity against tuberculosis in patients coinfected with HIV-1 and tuberculosis with effective antiretroviral therapy: assessment by determination of CD69 expression on T cells after tuberculin stimulation

Whether immunity against opportunistic pathogens can be fully restored by control of HIV-1 replication remains open to question. This longitudinal study was conducted to measure anti-tuberculosis (TB) cellular immunity in 13 HIV-1/TB-coinfected patients effectively treated by highly active antiretroviral therapy (HAART) in a period of 12 months. In this study, anti-TB cellular immunity was assessed by determining the frequencies of CD 69 expression on CD4+ and CD8+ T cells in response to purified protein derivative (PPD) stimulation (abbreviated as %CD4+CD69 to PPD and %CD8+CD69 to PPD). Here, we show that %CD4+CD69 to PPD correlated with the results of tuberculin skin tests and interferon-gamma (IFN-gamma) production from PPD-stimulated CD4+ T cells, and %CD8+CD69 to PPD also correlated with CD8+ T cell-mediated PPD-specific cytolysis. In overall analysis for these 13 patients, both %CD4+CD69 to PPD and %CD8+CD69 to PPD increased significantly during the 12 months (p =. 003 and p <.001, respectively). However, we found %CD4+CD69 to PPD or %CD8+CD69 to PPD failed to increase substantially in some patients (i.e., immunologic nonresponders). A significantly higher proportion of patients whose baseline CD4+ count was <50 cells/mm3 were considered to be CD4+ nonresponders compared with those whose baseline CD4+ count was >50 cells/mm3. Furthermore, baseline CD4+ cell count in nonresponders is significantly lower than that in responders, although the effectiveness of HAART did not differ between them. Our results indicate that PPD-specific frequencies of CD69 expression may be used as surrogate markers of anti-TB cellular immunity. By this method, we show that full reconstitution of anti-TB cellular immunity in HIV-1/TB coinfected patients may not necessarily be achieved by "successful" HAART and may be influenced by the baseline immune status when HAART is started. These data suggest that the decision to discontinue secondary prophylaxis for opportunistic infections should be cautiously made, even when the CD4+ cell count has significantly increased.

Radiation-induced hearing impairment in patients treated for malignant parotid tumor

Radiation-induced hearing loss was evaluated in 21 patients with unilateral malignant parotid tumors treated with surgery and radiotherapy. The contralateral ear was used as a control. Eight patients (38%) were found to have a reduction in static compliance of the tympanic membrane (type B tympanogram) in the irradiated ear. By audiometry, significant hearing loss was found in 9 patients (43%). These hearing losses were mainly sensorineural, as shown by a similar reduction in both air and bone conduction, although mixed-type hearing loss existed in some patients. A statistically significant difference in incidence of 67% versus 0% (p = .0085) was noted for patients with a cochlear dose of greater than or equal to 60 Gy, in comparison to those receiving doses of less than 60 Gy. A type B tympanogram was also found to be a prognostic factor for significant sensorineural hearing loss. Patients with type B tympanograms had a much higher incidence of significant sensorineural hearing loss than those with type A tympanograms (88% versus 15%, p = .02). This study clearly shows that radiotherapy can induce significant hearing impairment, especially when the cochlear doses are higher than 60 Gy.