Defective monocyte plasticity and altered cAMP pathway characterize USB1-mutated poikiloderma with neutropenia Clericuzio type

Poikiloderma with neutropenia (PN) Clericuzio type (OMIM #604173) is a rare disease with areas of skin hyper- and hypopigmentation caused by biallelic USB1 variants. The current study was spurred by poor healing of a perianal tear wound in one affected child homozygous for c.266-1G>A (p.E90Sfster8) mutation, from a family reported previously. Treatment with G-CSF/CSF3 or GM-CSF/CSF2 transiently increased neutrophil/monocytes count with no effect on wound healing. Analysis of peripheral blood revealed a lack of non-classical (CD14+/- CD16+ ) monocytes, associated with a systemic inflammatory cytokine profile, in the two affected brothers. Importantly, despite normal expression of cognate receptors, monocytes from PN patients did not respond to M-CSF or IL-34 in vitro, as determined by cytokine secretion or CD16 expression. RNAseq of monocytes showed 293 differentially expressed genes, including significant downregulation of GATA2, AKAP6 and PDE4DIP that are associated with leucocyte differentiation and cyclic adenosine monophosphate (cAMP) signalling. Notably, the plasma cAMP was significantly low in the PN patients. Our study revealed a novel association of PN with a lack of non-classical monocyte population. The defects in monocyte plasticity may contribute to disease manifestations in PN and a defective cAMP signalling may be the primary effect of the splicing errors caused by USB1 mutation.

Enzyme-Mediated Nerve Growth Factor Release from Nanofibers Using Gelatin Microspheres

Spinal cord injury is a complex environment, with many conflicting growth factors present at different times throughout the injury timeline. Delivery of multiple growth factors has received mixed results, highlighting a need to consider the timing of delivery for possibly antagonistic growth factors. Cell-mediated degradation of delivery vehicles for delayed release of growth factors offers an attractive way to exploit the highly active immune response in the spinal cord injury environment. In this study, growth factor-loaded gelatin microspheres (GMS) combined with methacrylated hyaluronic acid (MeHA) were electrospun to create GMS fibers (GMSF) for delayed release of growth factors (GFs). GMS were successfully combined with MeHA while electrospinning, with an average fiber diameter of 365 ± 10 nm and 44% ± 8% fiber alignment. GMSF with nerve growth factor (NGF) was tested on dissociated chick dorsal root ganglia cells. We further tested the effect of M1 macrophage-conditioned media (M1CM) to simulate macrophage invasion after spinal cord injury for cell-mediated degradation. We hypothesized that neurons grown on GMSF with loaded NGF would exhibit longer neurites in M1CM, showing a release of functional NGF, as compared with controls. GMSF in M1CM was significantly different from MeHA in serum-free media (SFM) and M0-conditioned media (M0CM), as well as GMSF in M0CM (p < 0.05). Moreover, GMSF + NGF in all media conditions were significantly different from MeHA in SFM and M0CM (p < 0.05). The goal of this study was to develop a biomaterial system where drug delivery is triggered by immune response, allowing for more control and longer exposure to encapsulated drugs. The spinal cord injury microenvironment is known to have a robust immune response, making this immune-medicated drug release system particularly significant for directed repair.

Senescence-associated secretory proteins induced in lung adenocarcinoma by extended treatment with dexamethasone enhance migration and activation of lymphocytes

There is a need to improve response rates of immunotherapies in lung adenocarcinoma (AC). Extended (7-14 days) treatment of high glucocorticoid receptor (GR) expressing lung AC cells with dexamethasone (Dex) induces an irreversible senescence phenotype through chronic induction of p27. As the senescence-associated secretory phenotype (SASP) may have either tumor supporting or antitumor immunomodulatory effects, it was interest to examine the effects of Dex-induced senescence of lung AC cells on immune cells. Dex-induced senescence resulted in sustained production of CCL2, CCL4, CXCL1 and CXCL2, both in vitro and in vivo. After Dex withdrawal, secretion of these chemokines by the senescent cells attracted peripheral blood monocytes, T-cells, and NK cells. Following treatment with Dex-induced SASP protein(s), the peripheral blood lymphocytes exhibited higher cell count and tumor cytolytic activity along with enhanced Ki67 and perforin expression in T and NK cells. This cytolytic activity was partially attributed to NKG2D, which was upregulated in NK cells by SASP while its ligand MICA/B was upregulated in the senescent cells. Enhanced infiltrations of T and NK cells were observed in human lung AC xenografts in humanized NSG mice, following treatment with Dex. The findings substantiate the idea that induction of irreversible senescence in high-GR expressing subpopulations of lung AC tumors using Dex pretreatment enhances tumor immune infiltration and may subsequently improve the clinical outcome of current immunotherapies.

Identification of Actionable Targets for Breast Cancer Intervention Using a Diversity Outbred Mouse Model

HER2-targeted therapy has improved breast cancer survival, but treatment resistance and disease prevention remain major challenges. Genes that enable HER2/Neu oncogenesis are the next intervention targets. A bioinformatics discovery platform of HER2/Neu-expressing Diversity Outbred (DO) F1 Mice was established to identify cancer-enabling genes. Quantitative Trait Loci (QTL) associated with onset ages and growth rates of spontaneous mammary tumors were sought. Twenty-six genes in 3 QTL contain sequence variations unique to the genetic backgrounds that are linked to aggressive tumors and 21 genes are associated with human breast cancer survival. Concurrent identification of TSC22D3, a transcription factor, and its target gene LILRB4, a myeloid cell checkpoint receptor, suggests an immune axis for regulation, or intervention, of disease. We also investigated TIEG1 gene that impedes tumor immunity but suppresses tumor growth. Although not an actionable target, TIEG1 study revealed genetic regulation of tumor progression, forming the basis of the genetics-based discovery platform.

Phonon anharmonicity in binary chalcogenides for efficient energy harvesting

Thermoelectric (TE) materials have received much attention due to their ability to harvest waste heat energy. TE materials must exhibit a low thermal conductivity (κ) and a high power factor (PF) for efficient conversion. Both factors define the figure of merit (ZT) of the TE material, which can be increased by suppressing κ without degrading the PF. Recently, binary chalcogenides such as SnSe, GeTe, and PbTe have emerged as attractive candidates for thermoelectric energy generation at moderately high temperatures. These materials possess simple crystal structures with low κ in their pristine forms, which can be further lowered through doping and other approaches. Here, we review the recent advances in the temperature-dependent behavior of phonons and their influence on the thermal transport properties of chalcogenide-based TE materials. Because phonon anharmonicity is one of the fundamental contributing factors for low thermal conductivity in SnSe, Sb-doped GeTe, and related chalcogenides, we discuss complementary experimental approaches such as temperature-dependent Raman spectroscopy, inelastic neutron scattering, and calorimetry to measure anharmonicity. We further show how data gathered using multiple techniques helps us understand and engineer better TE materials. Finally, we discuss the rise of machine learning-aided efforts to discover, design, and synthesize TE materials of the future.

Review of immune checkpoint inhibitors in immuno-oncology

Tumor cells predominantly express self-antigens and overcoming self-tolerance is the primary challenge to effective immunotherapy. Tumors also express ligands for co-inhibitory molecules on immune cells, in order to suppress anti-tumor immunity. Over a decade ago, the first antibodies generated to block the co-inhibitory molecule CTLA-4 was tested in patients with metastatic melanoma. Results from this landmark trial have informed not only the current landscape of checkpoint blockade but also the way in which immunotherapy trial outcomes are determined. Antibodies targeting PD-1 and its ligand, PD-L1, soon followed and use of these checkpoint inhibitors (ICIs) have expanded exponentially. ICI treatment has shown long-lasting clinical benefit in several tumor types and patients refractory to other treatments can often respond to ICI therapy. On the other hand, in some tumor types, the response to ICI is short-lived and tumors eventually recur. Current clinical trials are focused on enhancing anti-tumor effects through combinations of multiple ICIs with agents which cause tumor death, particularly in solid tumors, in order to enhance antigen presentation. It is also important to define which patients will respond to therapy with ICIs as over half of all patients suffer from immune-related adverse events (irAE), some of which are severe and long-lasting.

Dementia Symptoms among Senior Citizens Living in Geriatric Homes of Kathmandu Valley

Background With increasing age, the older population becomes more susceptible to mental disorders. It is important to recognize and develop an understanding of psychiatric morbidity particularly among the residents of geriatric homes in resource-poor settings. Objective To assess the prevalence and associated factors of dementia symptoms among Nepalese senior citizens living in geriatric homes of Kathmandu valley. Method A cross-sectional study was conducted among 304 senior citizens living in geriatric homes of Kathmandu valley. Cognitive Impairment Test (CIT), was used to assess dementia symptoms. Bivariate and multivariate logistic regressions were performed. All the variables that were significant at p < 0.05 level in the bivariate analysis were included in the multivariate regression model and statistical significance was declared at p < 0.05 with a 95.00% confidence interval (CI). Result This study showed 75.65%, of the participants, had dementia symptoms. In the multivariate logistic regression analysis, female respondents (AOR=2.94, 95% CI=1.31-6.57), respondents never received geriatric allowances (AOR=2.46, 95% CI=1.22-4.98), respondent's history of alcohol consumption habits (AOR=2.04, 95% CI=1.01-4.11) and non-vegetarian diet habits (AOR= 2.31, 95% CI=1.12-4.76) were found more likely to had higher dementia symptoms whereas, literate participants (AOR=0.19, 95% CI=0.08-0.43) were less likely to had dementia symptoms. Conclusion The high prevalence of dementia symptoms among senior citizens living in geriatric homes in the Kathmandu valley indicates an urgent need for early diagnosis and treatment of mental disorders among senior citizens to improve their quality of life and well-being.

Therapeutic and Medicinal Uses of Terpenes

Terpenes, also known as terpenoids are the largest and most diverse group of naturally occurring compounds. Based on the number of isoprene units they have, they are classified as mono, di, tri, tetra, and sesquiterpenes. They are mostly found in plants and form the major constituent of essential oils from plants. Among the natural products that provide medical benefits for an organism, terpenes play a major and variety of roles. The common plant sources of terpenes are tea, thyme, cannabis, Spanish sage, and citrus fruits (e.g., lemon, orange, mandarin). Terpenes have a wide range of medicinal uses among which antiplasmodial activity is notable as its mechanism of action is similar to the popular antimalarial drug in use—chloroquine. Monoterpenes specifically are widely studied for their antiviral property. With growing incidents of cancer and diabetes in modern world, terpenes also have the potential to serve as anticancer and antidiabetic reagents. Along with these properties, terpenes also allow for flexibility in route of administration and suppression of side effects. Certain terpenes were widely used in natural folk medicine. One such terpene is curcumin which holds anti-inflammatory, antioxidant, anticancer, antiseptic, antiplasmodial, astringent, digestive, diuretic, and many other properties. Curcumin has also become a recent trend in healthy foods and open doors for several medical researches. This chapter summarizes the various terpenes, their sources, medicinal properties, mechanism of action, and the recent studies that are underway for designing terpenes as a lead molecule in the modern medicine.

Knowledge Regarding Earthquake Preparedness Among the People of Biratnagar Sub-Metropolis of Eastern Nepal

IntroductionEarthquake preparedness is necessary strategy and action that is done before an earthquake happens in order to decrease mortality and morbidity. Earthquake in Nepal killed more than 8000 people in 2015. Increased number of deaths were mainly considered due to lack of earthquake preparedness and necessary safety measures.ObjectivesThe aim of this study was to assess the knowledge regarding earthquake preparedness and to find out relationship between the level of knowledge and with their selected socio-demographic variables.MethodologyA cross sectional study was conducted among the people residing in ward number 11 and 18 of Biratnagar sub-metropolis from 1st July to 1st October 2015. Wards were selected through simple random sampling and 110 participants were selected through convenient sampling. Each participant had completed an interviewer-administered questionnaire. Descriptive and inferential statistics was applied for data analysis.ResultAmong 110 participants, 51.8% had knowledge score between 51% to 75%, 24.6% had knowledge score below 50% and only 23.6% had knowledge score above 75%. This research showed that there was significant relationship between knowledge and age, marital status, educational status, occupation and monthly income. Participants from 20 to 39 year had more knowledge score than participants from 40 to 60 years. The higher the educational status; more was the knowledge score. Unmarried participants had more knowledge score than married participants and business holders had more knowledge score than other occupation category.ConclusionEarthquake preparedness knowledge among participants was inadequate. Therefore, educational intervention program regarding this is required in these areas. Birat Journal of Health Sciences Vol.2/No.1/Issue 2/ Jan - April 2017, page: 201-205

Diabetes Awareness Among Patient's Attendant Visiting in Teaching Hospital of Eastern Nepal

IntroductionDiabetes is a prevalent non-communicable disease. It has  increasing global trend. In Nepal, the prevalence of diabetes is also increasing. Awareness is vital to  revent and early diagnosis of diabetes.ObjectivesThe objective of study was to assess the awareness of diabetes and its related factors.MethodologyThis was a hospital based cross sectional study. Total of 503 patient's a

Treatment Outcome of Drug Resistance Tuberculosis From a Centre of Eastern Region, Nepal

Introduction Drug resistance tuberculosis (DRTB) has become major problem worldwide with difficulty in treatment. Objective The study is conducted to find the incidence and outcomes of DRTB in one of the eastern tuberculosis treatment centre of Nepal.Methodology We collected all the cases of DRTB being treated from national anti-tuberculosis association of Biratnagar, Nepal. There were altogether 154 patients, who had sputum culture with resistance of at least one anti tubercular drug (ATD), included in this study.Results Of 154 total patients, 36 patients were resistant to rifampicin only, 84 patients were resistant to isoniazid and rifampicin, 18 patients were resistant to isoniazid, rifampicin and ethambutol and 16 patients were resistant to isoniazid, rifampicin and either streptomycin or fluoroquinolone. There was overall 71% cure rate in case of drug resistance tuberculosis. There was only statistical difference between cured and died patients in case of sputum conversion time with earlier sputum conversion in cured patients. Similarly, patients who were previously treated with category 2 ATD had only resistance to ethambutol or streptomycin or fluoroquinolone besides resistance to isoniazid and rifampicin compared to new patients and patients treated with category 1 regimen; as these groups were not found to be resistant to first three drugs.Conclusion There was overall 71% cure rate in case of drug resistance tuberculosis. Earlier sputum conversion was seen in cured patients compared to those who died during the treatment. Multiple drugs were resistant in patients previously treated with category 2 Anti-tubercular drugs.Birat Journal of Health Sciences 2016 1(1): 20-26

Effectiveness of Educational Intervention Programme on Knowledge Regarding Breast Self Examination Among Higher Secondary School Girls of Biratnagar

Introduction Breast self-examination (BSE) is a self-generated, non-invasive and non-irradiative method of breast cancer detection. Self examination of the breasts each month after the menstrual cycle is the simplest yet extremely important way to detect early breast cancer. It has been observed that women can detect 95% of breast cancers and 65% of early minimal breast cancers themselves. This method is harmless, less time consuming and can be performed by any woman.Objective To assess the effectiveness of educational intervention programme regarding Breast Self Examination among girl students of study school.Methodology Pre experimental one group pre-test post-test design was adopted for this study. In total, 61 girls were included. The result were analysed by using both descriptive as well as inferential statistics.Results In pre-test 75.4% had inadequate and only 1.6% had adequate knowledge regarding Breast Self Examination, in contrast, after the intervention the adequate knowledge was increased to 62.3%. The overall mean score was increased from 33.07% to 85.14%. The test of significance revealed that the increment in BSE knowledge score due to program intervention was highly significant (P< 0.001).Conclusion The educational intervention programme on BSE was found to be highly effective as the knowledge score was significantly increased after intervention of the package among higher secondary school girls.Birat Journal of Health Sciences 2016 1(1): 13-19

Preferential expression of functional IL-17R in glioma stem cells: potential role in self-renewal

Gliomas are the most common primary brain tumor and one of the most lethal solid tumors. Mechanistic studies into identification of novel biomarkers are needed to develop new therapeutic strategies for this deadly disease. The objective for this study was to explore the potential direct impact of IL-17−IL-17R interaction in gliomas. Immunohistochemistry and flow cytometry analysis of 12 tumor samples obtained from patients with high grade gliomas revealed that a considerable population (2–19%) of cells in all malignant gliomas expressed IL-17RA, with remarkable co-expression of the glioma stem cell (GSC) markers CD133, Nestin, and Sox2. IL-17 enhanced the self-renewal of GSCs as determined by proliferation and Matrigel^® colony assays. IL-17 also induced cytokine/chemokine (IL-6, IL-8, interferon-γ-inducible protein [IP-10], and monocyte chemoattractant protein-1 [MCP-1]) secretion in GSCs, which were differentially blocked by antibodies against IL-17R and IL-6R. Western blot analysis showed that IL-17 modulated the activity of signal transducer and activator of transcription 3 (STAT3), nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB), glycogen synthase kinase-3β (GSK-3β) and β-catenin in GSCs. While IL-17R-mediated secretion of IL-6 and IL-8 were significantly blocked by inhibitors of NF-κB and STAT3; NF-κB inhibitor was more potent than STAT3 inhibitor in blocking IL-17-induced MCP-1 secretion. Overall, our results suggest that IL-17–IL-17R interaction in GSCs induces an autocrine/paracrine cytokine feedback loop, which may provide an important signaling component for maintenance/self-renewal of GSCs via constitutive activation of both NF-κB and STAT3. The results also strongly implicate IL-17R as an important functional biomarker for therapeutic targeting of GSCs.

Modulation of Hemopoiesis in Normal and Tumor-Bearing Mice on in Vivo Administration of FK565

The present investigations were undertaken to study the effect of in vivo administration of FK565 on the process of hemopoiesis in normal and tumor-bearing mice. FK565 administration (10 mg/kg body weight) of normal mice resulted in an enhancement of the bone marrow cell (BMC) colony foming activity (CFA) and proliferation in vitro. The counts of granulocyte- and granulocyte macrophage-colony forming units (CFU-G and CFU-GM) were significantly enhanced in the BMC of FK565-treated group. The total leukocyte count (TLC) was also augmented after FK565 administration. The differential leukocyte count (DLC) revealed an enhancement of the neutrophil count in the FK565-treated mice. A similar pattern of BMC proliferation, CFA, TLC and DLC was observed in P815 tumor-bearing mice. FK565 administration of the tumor-bearing mice, however, did not significantly alter the CFA, TLC and DLC.

Implications of the USP10-HDAC6 axis in lung cancer - A path to precision medicine

Lung cancer is the leading cause of cancer death among both men and women in the United States. Because lung cancer is genetically heterogeneous, tailored therapy alone or in combination with chemotherapy would increase patient overall survival as compared with the one-size-fits-all chemotherapy. TP53-mutant lung cancer accounts for more than half of all lung cancer cases and is oftentimes more aggressive and resistant to chemotherapy. Directly targeting mutant p53 has not yet been successful, so identification of novel therapy targets and biomarkers in the TP53-mutant lung cancer is urgently needed to increase the overall survival in this subgroup. Deubiquitinating enzymes (DUBs) regulate a vast majority of proteins (DUBs' substrates) via removal of ubiquitin moieties or ubiquitin chains from these proteins, thereby altering the stability and/or functions of these substrates. In this review, we will focus on a DUB, referred to as ubiquitin-specific peptidase 10 (USP10) whose substrates include both oncogenic proteins and tumor suppressors. Therefore, targeting USP10 in cancer is highly context-dependent. Here, we will discuss USP10's functions in cancer by examining its various known substrates. In particular, we will elaborate our recent findings in the oncogenic role of USP10 in the TP53-mutant subgroup of lung cancer, focusing on USP10's function in the DNA damage response (DDR) via histone deacetylase 6 (HDAC6). Overall, these findings support the notion that targeting USP10 in the TP53-mutant subgroup of NSCLC would sensitize patients to cisplatin-based chemotherapy. Generating potent and specific clinically relevant USP10 inhibitors would benefit the TP53-mutant subgroup of NSCLC patients.

Application of Bioactive Compounds from Scutellaria in Neurologic Disorders

Inflammation of the brain is one of the most highly researched yet mysterious areas in modern day neurology. The process of inflammation is a normal mechanism of wound healing that can result from acute injuries such as traumas or can be caused by genetic/environmental factors. After the initial insult, the immune system defenses, specifically microglial cells, are activated in order to combat the infection or injury. However, prolonged or chronic inflammation is often deleterious due mainly to accumulation of free reactive oxygen species (ROS) and other pro-inflammatory cytokines in the brain FADDIN EN.CITE. Plant-derived natural compounds have the potential to ameliorate the causes and symptoms of neuroinflammation, due to their various anti-oxidant and anti-inflammatory activities, without completely muting the immune defenses. Scutellaria is a perennial plant in the mint family that has been used to treat diseases in Asia and Eastern Europe throughout history. This chapter reviews the active components of various Scutellaria species and their mechanisms of action to prevent chronic neurologic disorders involving neuroinflammation and neurodegeneration.

Anti-proliferative effects of γ-tocotrienol are associated with suppression of c-Myc expression in mammary tumour cells

OBJECTIVES

Aberrant c-Myc activity plays a central role in cancer transformation. γ-tocotrienol is a member of the vitamin E family that displays potent anti-cancer activity. Here, studies were conducted to determine the role of c-Myc in mediating anti-proliferative effects of γ-tocotrienol in mammary cancer cells.

MATERIALS AND METHODS

Treatment effects on mouse +SA and human MCF-7 mammary cancer cell proliferation were determined by MTT assay and Ki-67 staining. Protein expression was determined by western blot analysis. Immunofluorescence staining and qRT-PCR were used to characterize cellular c-Myc and MYC levels respectively.

RESULTS

Anti-proliferative effects of γ-tocotrienol were associated with reduction in total c-Myc and phosphorylated-c-Myc-serine 62, and increase in phosphorylated-c-Myc-threonine 58 levels. γ-tocotrienol also reduced PI3K/Akt/mTOR and Ras/MEK/Erk mitogenic signalling, cyclin D1 and cyclin-dependent kinase 4 levels, and increased p27 levels. However, γ-tocotrienol had no effect on MYC mRNA levels. γ-tocotrienol also increased levels of FBW7 (E3 ligase that initiates ubiquitination of c-Myc), but had no effect on serine/threonine phosphatase PP2A or isomerase Pin 1 levels. Combined treatment with GSK3α/β inhibitor LiCl or proteasome inhibitor MG132 blocked γ-tocotrienol-induced reductions in c-Myc.

CONCLUSIONS

These findings indicate that anti-proliferative effects of γ-tocotrienol are associated with reduction in c-Myc that results from increase in GSK-3α/β-dependent ubiquitination and degradation, rather than from reduction in c-Myc synthesis in +SA and MCF-7 mammary cancer cells.

Abstract P3-03-09: Anti-proliferative dose of g-tocotrienol decreases c-Myc stability in breast cancer cells

c-Myc is a helix-loop-helix leucine zipper transcription factor that has essential role in controlling many cell functions, including cell proliferation, differentiation, growth and apoptosis. However, c-Myc overexpression has been reported to occur in a majority of breast cancers and is associated with a poor prognosis. Apart from MYC gene amplification and translocation, it is also tightly regulated by signaling pathway that involves series of interdependent phosphorylation events. Myc stability is increased by phosphorylation at serine 62 (S62) by extracellular signal-regulated kinase (ERK) or cyclin dependent kinase (CDK), whereas subsequent phosphorylation at threonine T58 (T58) by glycogen synthase kinase b (GSK3 β) triggers dephosphorylation of S62 by protein phosphatase 2A-B56α (PP2A- B56α), leading to unbiquitination by SCF-Fbw7 E3 ligase and proteasomal degradation. Additionally, it has been shown that primary human breast cancer cells display increased levels of S62 Myc and decreased level of T58 Myc and mutations in this pathway result in accumulation of high level of oncogenic S62 Myc leading to tumorigenesis. γ-tocotrienol (γT3), a member of the vitamin E family has potent antiproliferative and apoptotic activity in a variety of cancer cell types at treatment doses that have little or no effect on normal cell viability or growth. Additionally, previous studies have shown that anti-proliferative dose of γT3 decreased c-Myc protein level in colorectal and pancreatic cancer cells. Therefore, studies were conducted to determine if γT3 decreases oncogenic S62 phosphorylation and triggers subsequent interdependent phosphorylation leading to c-Myc degradation in neoplastic mouse +SA and MCF-7 human epithelium mammary cancer cell lines. Treatment with 1-8μM γT3 resulted in a dose-responsive inhibition of +SA and MCF-7 breast cancer cell growth. Western blot analysis showed that antiproliferative dose of γ-tocotrienol resulted in a decrease in total c-Myc, phospho S62 Myc and increase in phospho T58 Myc in +SA and MCF-7 breast cancer cells. Further studies showed that similar doses decreased phosphorylated (activated) Akt and its downstream targets GSK-3β and mTOR, as well as phosphorylated (activated) 44/41 MAPK or (Erk 1/2). Additional studies showed that the antiproliferative effects of γT3 were also associated with a decrease in cyclin D1 and cyclin dependent kinase 4 (CDK4). Western blot analysis has also shown an increase in FBw7, an E3 ligase that initiates ubiquitination of c-Myc. However, no change in protein phosphatase 2A (PP2A) and Pin 1 prolyl isomerase was observed in +SA and MCF-7 mammary cancer cells. In summary, these findings demonstrate that the antiproliferative effects of γ-tocotrienol are mediated, at least in part, by decreasing oncogenic c-Myc (S62) levels and a corresponding reduction in Akt/mTOR and MAPK signaling. These effects were also associated with an increase in GSK-3β-induced phosphorylation of T58 and the promotion of the ubiquitination and degradation of c-Myc. This study was supported by grants from First Tech International Ltd., and the Malaysian Palm Oil Council.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-03-09.

Abstract P3-03-11: Oxazine derivatives of g- and D- tocotrienols display potent anticancer effects in vivo

Breast cancer is a multi-stage process which leads to the accumulation of abnormal cells arising from excessive proliferation, lack of apoptosis or a combination of both. Natural compounds such as g-tocotrienol have been shown to selectively inhibit cancer cell growth without harming normal cell viability with little or no adverse side effects. The antiproliferative and apoptotic effects of the tocotrienol isoform, γ-tocotrienol, have been firmly established in various cancer types. However, in vivo studies have provided mixed results, attributed to γ-tocotrienol rapid clearance and low bioavailability. In order to improve anticancer potency and bioavailability in vivo, γ- and Δ-tocotrienol were chemically modified with electrophilic substitution reactions on their chromane ring using Mannich and Lederer-Manasse reactions, resulting in the synthesis of various oxazine derivatives. Several of these oxazine derivatives (compounds 26, 31, 39, 40 and 44) were found to display potent anticancer activity as compared to their parent compounds when tested on +SA mammary cancer cells grown in culture. These in vitro studies were followed up with in vivo studies to determine the anticancer effects of oxazine derivatives on the growth of mammary tumors in mice. Female syngeneic BALB/c mice, 4-6 week old were inoculated with 1×106 +SA mammary tumor cells in the left mammary pad. Once tumor size reached 5mm in diameter, animals were divided into different treatment groups and received an intra-tumoral injection injected of 0-120μg/20μl tocotrienol or its derivative every other day for 11 days. Afterwards, mice were sacrificed, tumors removed and placed in -80°C until further analysis. Results from these studies showed that tumor growth rate was significantly reduced in the oxazine derivative treated animals as compared to the vehicle-treated controls. Western blot analysis of tumor samples showed that the growth inhibitory effects of tocotrienol derivatives was also associated with a significant reduction in phosphorylated (activated) Akt and reductions in cell cycle regulatory proteins cyclin D1 and cyclin dependent kinases (CDK2, CDK4 and CDK6). In addition, oxazine derivative treatment was also associated with a large increase in CDK inhibitors p21 and p27, as compared to tumors obtained from the vehicle-treated control mice. Western blot analysis also showed that tumor from oxazine-derivative treated mice displayed a large reduction in NFκB levels and its downstream gene product COX-2. In summary, oxazine derivatives of tocotrienols display more potent anticancer activity both in vitro and in vivo, as compared to their parent compounds and suggest that these tocotrienol derivatives may provide some benefit as novel anticancer therapeutic agents. This work was supported, in part, by First Tec International Ltd. (Hong Kong), Malaysian Palm oil Council and the Louisiana Cancer Foundation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-03-11.

Role of Th17/IL-17 inflammatory axis in the progression of malignant gliomas (P2095)

Recent studies on extra-cranial tumors have demonstrated a strong relationship between tumor progression and inflammation. The Th17 cells, an inflammatory T cell subtype, have been implicated with either pro- or anti-tumor activity, depending on the tumor type. Th17 cells or the cytokine IL-17 remain to be studied in malignant gliomas. The objective of our study is to explore the axis of inflammatory interactions in glioma progression by focusing on the functional significance of IL-17 and IL17 receptor (IL17R) in the tumor. Our experimental strategies include in vitro 3D culture of IL17R+ glioma cells for proliferation/differentiation and cell signaling assays and ex vivo analysis of clinical glioma tissues via multi-color flow cytometry and immunohistochemistry. We report here that: 1) There is considerable prevalence of IL-17-secreting and IL17-inducing (Th17 and CD11b+ myeloid) cells among glioma-infiltrating immune cells; 2) Th17 cells induced by glioma-derived factors, in the presence of TGF-β1, shows potential immune-suppressive phenotype; 3) IL17R is preferentially expressed in glioma stem-like cells (GSCs); 4) IL17 enhances the proliferation of GSCs in matrigel cultures; 5) IL17 induces phosphorylation of STAT3, NF-κB, and GSK-3β, while also enhancing β-catenin activity in GSCs. This study provides novel insight into inflammatory axis in glioma progression, which may have significant impact on clinical interventions in patients with malignant gliomas.

Abstract 3982: Immuno-sensitization of malignant gliomas by natural polyphenols

Malignant gliomas are the most common primary brain tumors with approximately 22,000 cases per year. In spite of aggressive surgery, radiotherapy and chemotherapeutic regimens, the median survival of patients with malignant gliomas is a dismal 15 months. The objective of our study was to explore the adjuvant therapeutic potential and associated molecular mechanisms of natural polyphenols stilbenes in malignant gliomas. Recent studies have demonstrated the efficacy of stilbenes in extracranial tumor models. Stilbenes, including resveratrol, were bioavailable in the brain even after low dose oral administration and there was no toxicity to normal tissue. On the contrary, these compounds were found to be neuroprotective in Alzheimer's disease models. Mechanistically, stilbenes modulate NF-κB, STAT3, wnt/β-catenin signaling and also inhibits antiapoptotic protein Bcl-xl. While these molecules are critical in imparting chemoresistance, they are also pivotal in inducing immune-resistance and pro-tumor immune infiltration in gliomas. We hypothesized that stilbenes enhance the efficacy of chemotherapy while also inhibiting immune-suppression and -resistance in malignant gliomas via overlapping molecular mechanisms. We observed significant positive interaction between Temozolomide and Resveratrol for inhibition of glioma proliferation. Resveratrol induced apoptosis in gliomas via inhibition of Bcl-2 and Bcl-xl, while STAT3 activity was also inhibited. Importantly, Resveratrol significantly enhanced the expression of TRAIL-R2 and MIC A/B in gliomas, making them vulnerable to lysis by CTLs and NK cells. Studies are underway to determine combined effect of DC-based immunotherapy and stilbenes against malignant gliomas using syngeneic, orthotopic mouse glioma models. The results can have significant impact in developing novel adjuvant studies to improve survival in patients with malignant gliomas.

Citation Format: Chandramouli Mandalaparty, Andrew Huang, Sandeep Mittal, Agnes M. Rimando, Q. Ping Dou, Prahlad Parajuli. Immuno-sensitization of malignant gliomas by natural polyphenols. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3982. doi:10.1158/1538-7445.AM2013-3982

Role of IL-17 in Glioma Progression

There is increasing evidence in the literature pointing to an important role of inflammation during initiation and progression of cancer. Glioblastoma is the most common malignant primary brain tumor with approximately 23,000 newly-diagnosed cases each year in the United States, and has a dismal median survival of only 15 months. Although the blood-brain barrier maintains an immune-privileged status of the brain under steady state, intracranial tumors including gliomas are invariably infiltrated with various types of immune cells. The T helper 17 (Th17) cells, a recently discovered interleukin (IL)-17-producing T cell subtype, have been reported in several extracranial and some intracranial tumors, where they have been implicated in either pro- or antitumor activity depending on the tumor type. Here, we present a succinct review of the current literature on the prevalence and potential role of IL-17 in malignant gliomas. Further mechanistic studies on IL-17 mediated inflammatory pathway in gliomas may provide with opportunities for novel immunotherapeutic interventions.

Level of compliance and factors associated with non-compliance to treatment among the mentally ill patients

Background: Mental illnesses are treatable and need medication and other therapies i.e. counseling, psychotherapy etc for the better outcome. Poor adherence to psychiatric medication regimens is a major obstacle to the effective care of persons who have chronic mental illness.Objectives: The study aims to identify the level of compliance and factors associated with non-compliance to treatment regimen.Methods: This was a hospital based cross sectional study carried out in psychiatric ward and OPD at B.P.Koirala Institute of Health Sciences, Dharan Nepal. A total of 150 patients were included as study samples using purposive sampling technique. Data was collected using self developed, pre tested, semi structured Pro forma by interview method.Results: Half of the patients showed average compliance. Thirty seven percentages of patients had good compliance and only 13% showed poor compliance. There was no association between drug compliance and demographic variables (p> 0.05). Drug compliance was significantly associated with factors such as drug related aspects, treatment access related factors, quality of interaction with treating team, family support, attitude towards mental illness and relatives' insight towards mental illness (p<0.05 ).Conclusion: The findings of the study highlighted the various factors such as drug related, social support, and treatment access related factors are influencing the drug compliance among the mentally ill patients.DOI: http://dx.doi.org/10.3126/hren.v10i2.6577 Health Renaissance 2012; Vol 10 (No.2); 113-117 

Generation and immunologic functions of Th17 cells in malignant gliomas

Th17 cells, a recently discovered inflammatory T cell subtype, have been implicated with autoimmune disorders. However, mechanism of generation or functions of intratumoral Th17 cells are still unclear. We have been investigating the mechanism of induction and role of Th17 cells in malignant gliomas using primary tumor as well as cell lines. We report here that: (1) a higher frequency of Th17 cells in gliomas were associated with higher number of myeloid (CD11b) cells as well as the expression of TGF-β1 or IL-6; (2) conditioned medium from glioma cells (Gl CM) induced Th17 cell differentiation, which was inhibited by anti-TGF-β1 and anti-IL-6; (3) glioma-associated monocytes secreted Th17-promoting cytokines IL-1β and IL-23; (4) CM from glioma and monocyte co-culture (Gl+Mo CM) induced high frequency of Th17 cells in naïve T cell culture, which was abrogated by anti-IL-1β and anti-IL-23 antibodies; (5) In vitro Gl+Mo CM-mediated Th17 generation was associated with a decrease in IFN-γ and a concomitant increase in IL-10 secretion. Anti-TGF-β1, but not anti-IL-6, significantly reversed this cytokine profile. These results demonstrate prevalence of Th17 cells in gliomas and implicate the cytokines derived from the tumor as well as infiltrating myeloid cells in the induction of Th17 cells in glioma microenvironment. Moreover, the data also suggest that glioma-associated Th17 cells may contribute to immune-suppression via TGF-β1-induced IL-10 secretion. Further studies on the mechanism of tumor-infiltration, developmental pathways, and pro-/anti-tumor functions of Th17 cells will provide rationale for developing novel adjuvant immunotherapeutic strategies for malignant gliomas.

Interaction between tumor and myeloid cells induce/expand Th17 cells in malignant gliomas (48.28)

Th17 cells, a recently discovered inflammatory T cell subtype, have been reported in several tumors, where they are implicated with either pro- or anti-tumor activity, depending on the tumor type. Th17 cells have not been studied with respect to brain tumors. We have been studying the mechanism of induction and role of Th17 cells in malignant gliomas using primary tumor as well as glioma cell lines. We report here that: 1) There is considerable prevalence of Th17 cells and myeloid (CD11b) cells among glioma-infiltrating immune cells; 2) Glioma cells express the cytokines TGF-β1 and IL-6, while the infiltrating myeloid cells express IL-1β and IL-23; 3) Naïve T cells cultured with anti-CD2/CD3/CD28-loaded microbeads in the presence of glioma culture supernatants differentiate into Th17 cells, which is inhibited by antibodies to TGF-β1 and IL-6; 4) Supernatant from glioma-monocyte co-culture generates significantly higher frequency of Th17 cells compared to glioma supernatant, which is abrogated by antibodies to IL-1β and IL-23. Moreover, 5) Th17 cells generated in the presence of supernatant from glioma-monocyte co-culture have low IFN-γ and high IL-10 expression, suggesting that glioma-associated Th17 cells may be immune suppressive. Further studies on the mechanism of tumor-infiltration, developmental pathways and pro-/anti-tumor functions of Th17 cells will provide rationale for developing novel adjuvant immunotherapeutic strategies for malignant gliomas.

Substance Use among Medical Students in Kathmandu Valley

Introduction: Substance use including tobacco and alcohol is the most important cause of preventable morbidity, disability, and premature mortality. The study aims to specify the prevalence and the pattern of use of different substance. Methods: A cross sectional study was performed amongst first year and final year students in four medical colleges in Kathmandu using self administered anonymous questionnaire.Data collectedfrom 446 students were analyzed. Results: Prevalence of substance use was found to be 60.3% among the medical students. Alcohol (57.6%) was the substance most prevalently used followed by tobacco (27.58%) and cannabis (12.8%). Mean age of first exposure was 17.94 (Confidence interval: 17.91-17.97). There was significant difference in the useof tobacco and cannabis amongst final year students than first year students. Male and female differed significantly in use of every substance except for benzodiazepine. Medical college, college and school were place of first exposure in 17.26%, 15.92% and 13.23% of the cases respectively. Family history was associated with substance use in medical students and was statistically significant (P<0.0001).Experimentation was the major reason for the use of most of the substances. Conclusions: Substance use is prevalent in male medical students of both first and final year. Hence steps should be initiated early in school, college and medical college to prevent substance use. Keywords: alcohol, medical students, substance use, tobacco.

Substance use among medical students in Kathmandu valley

INTRODUCTION

Substance use including tobacco and alcohol is the most important cause of preventable morbidity, disability, and premature mortality. The study aims to specify the prevalence and the pattern of use of different substance.

METHODS

A cross sectional study was performed amongst first year and final year students in four medical colleges in Kathmandu using self administered anonymous questionnaire.Data collectedfrom 446 students were analyzed.

RESULTS

Prevalence of substance use was found to be 60.3% among the medical students. Alcohol (57.6%) was the substance most prevalently used followed by tobacco (27.58%) and cannabis (12.8%). Mean age of first exposure was 17.94 (Confidence interval: 17.91-17.97). There was significant difference in the useof tobacco and cannabis amongst final year students than first year students. Male and female differed significantly in use of every substance except for benzodiazepine. Medical college, college and school were place of first exposure in 17.26%, 15.92% and 13.23% of the cases respectively. Family history was associated with substance use in medical students and was statistically significant (P<0.0001).Experimentation was the major reason for the use of most of the substances.

CONCLUSIONS

Substance use is prevalent in male medical students of both first and final year. Hence steps should be initiated early in school, college and medical college to prevent substance use.

Delayed growth of glioma by Scutellaria flavonoids involve inhibition of Akt, GSK-3 and NF-κB signaling

Plants of the genus Scutellaria constitute one of the common components of Eastern as well as traditional American medicine against various human diseases, including cancer. In this study, we examined the in vivo anti-glioma activity of a leaf extract of Scutellaria ocmulgee (SocL) while also exploring their potential molecular mechanisms of action. Oral administration of SocL extract delayed the growth of F98 glioma in F344 rats, both in intracranial and subcutaneous tumor models. Immunohistochemistry revealed inhibition of Akt, GSK-3α/β and NF-κB phosphorylation in the subcutaneous tumors following treatment with Scutellaria. The SocL extract as well as the constituent flavonoid wogonin also showed dose- and time-dependent inhibition of Akt, GSK-3α/β and NF-κB in F98 cell cultures in vitro, as determined by western blot analysis. Pharmacologic inhibitors of PI3K and NF-κB also significantly inhibited the in vitro proliferation of F98 glioma cells, indicating the key role of these signaling molecules in the growth of malignant gliomas. Transfection of F98 cells with constitutively active mutant of AKT (AKT/CA), however, did not significantly reverse Scutellaria-mediated inhibition of proliferation, indicating that Scutellaria flavonoids either directly inhibited Akt kinase activity or acted downstream of Akt. In vitro Akt kinase assay demonstrated that the SocL extract or wogonin could indeed bind to Akt and inhibit its kinase activity. This study provides the first in vivo evidence and mechanistic support for anti-glioma activity of Scutellaria flavonoids and has implications in potential usage of Scutellaria flavonoids in adjuvant therapy for malignant tumors, including gliomas.

In vitro antitumor mechanisms of various Scutellaria extracts and constituent flavonoids

Scutellaria is a traditional herbal remedy with potential anti-cancer activity. The purpose of this study was to evaluate anticancer mechanisms of thirteen Scutellaria species and analyze their leaf, stem and root extracts for levels of common biologically active flavonoids: apigenin, baicalein, baicalin, chrysin, scutellarein, and wogonin. Malignant glioma, breast carcinoma and prostate cancer cells were used to determine tumor-specific effects of Scutellaria on cell proliferation, apoptosis and cell cycle progression, via the MTT assay and flow cytometry-based apoptosis and cell cycle analysis. The extracts and individual flavonoids inhibited the proliferation of malignant glioma and breast carcinoma cells without affecting primary or non-malignant cells. The flavonoids exhibited different mechanisms of anti-tumor activity as well as positive interactions. The antitumor mechanisms involved induction of apoptosis and cell cycle arrest at G1/G2. Of the extracts tested, leaf extracts of S. angulosa, S. integrifolia, S. ocmulgee and S. scandens were found to have strong anticancer activity. This study provides basis for further mechanistic and translational studies into adjuvant therapy of malignant tumors using Scutellaria leaf tissues.

Lactate and malignant tumors: a therapeutic target at the end stage of glycolysis

Metabolic aberrations in the form of altered flux through key metabolic pathways are primary hallmarks of many malignant tumors. Primarily the result of altered isozyme expression, these adaptations enhance the survival and proliferation of the tumor at the expense of surrounding normal tissue. Consequently, they also expose a unique set of targets for tumor destruction while sparing healthy tissues. Despite this fact, development of drugs to directly target such altered metabolic pathways of malignant tumors has been under-investigated until recently. One such target is the ultimate step of glycolysis, which, as expected, presents itself as a metabolic aberration in most malignant tumors. Termed "aerobic glycolysis" due to abnormal conversion of pyruvic acid to lactic acid even under normoxia, the altered metabolism requires these tumors to rapidly efflux lactic acid to the microenvironment in order to prevent poisoning themselves. Thus, exposed is a prime "choke-point" to target these highly malignant, frequently chemo- and radio- resistant tumors. This review will focus on current outcomes in targeting lactate efflux in such tumors using glioma as a model, an ongoing project in our laboratory for the past half-decade, as well as supporting evidence from recent studies by others on targeting this "tail-end" of glycolysis in other tumor models.

Dendritic cell-based active specific immunotherapy for malignant glioma

Immunotherapy is an appealing therapeutic modality for malignant gliomas because of its potential to selectively target residual tumor cells that have invaded the normal brain. Most immunotherapeutic studies are designed to exploit the capacity of dendritic cells for inducing cell-mediated effects as well as immune memory responses for destroying residual tumor cells and preventing recurrence. Although initial clinical studies on dendritic cell-based immunotherapy resulted in very limited success, they have prompted many new studies on exploring strategies to induce a more robust antitumor immune response by using novel adjuvants for maturation and activation of dendritic cells. More studies have focused on the mechanisms of immune suppression by tumor cells and the role of regulatory T cells in tumor growth and progression. In this article, the authors review the evolution of dendritic cell-based immunotherapeutic strategies for adjuvant treatment of malignant gliomas. The authors also discuss how new knowledge on tumor-intrinsic mechanisms of tolerance induction and immunosuppression are likely to shape the future of immunotherapy for high-grade gliomas.

Silencing of monocarboxylate transporters via small interfering ribonucleic acid inhibits glycolysis and induces cell death in malignant glioma: an in vitro study

OBJECTIVE

Dependence on glycolysis is a hallmark of malignant tumors. As a consequence, these tumors generate more lactate, which is effluxed from cells by monocarboxylate transporters (MCTs). We hypothesized that 1) MCT expression in malignant tumors may differ from normal tissue in quantity, isoform, or both; and 2) silencing MCT expression would induce intracellular acidification, resulting in decreased proliferation and/or increased cell death.

METHODS

We quantified expression of MCT isoforms in human glioblastoma multiforme and glioma-derived cells lines by Western blot analysis. MCTs that were abundant or specific to glioma then were targeted in the model U-87 MG glioma cell line via small interfering ribonucleic acid-mediated gene silencing and tested for inhibition of lactate efflux, intracellular pH changes, reduced proliferation, and/or induction of cell death.

RESULTS

MCT 1 and 2 were the primary isoforms expressed in human glioblastoma multiforme and glioma-derived cell lines. In contrast, MCT 3 was the predominantly expressed isoform in normal brain. Small interfering ribonucleic acid specific for MCT 1 and 2 reduced expression of these isoforms in U-87 MG cells to barely detectable levels and reduced lactate efflux by 30% individually and 85% in combination, with a concomitant decrease of intracellular pH by 0.6 units (a fourfold increase in intracellular H(+)). Prolonged silencing of both MCTs reduced viability by 75% individually and 92% in combination, as measured by both phenotypic and flow cytometric analyses.

CONCLUSION

MCT targeting significantly reduced the viability of U-87 MG cells mediated by both apoptosis and necrosis. This indicates that the strategy may be a useful therapeutic avenue for treatment of patients with malignant glioma.

Antidiabetic plants used by Sikkim and Darjeeling Himalayan tribes, India

Sikkim and Darjeeling Himalayan region is characterized by a rich floral diversity and an equally rich ethnomedicinal tradition. Herbal medicine is the dominant system of medicine practiced by the local tribes of this region for the treatment of diabetes. During the course of the present studies it was found that 37 species of plants belonging to 28 families are used as antidiabetic agents in the folk medicinal practices in the region and 81% of these plants are hitherto unreported as hypoglycemic agents. This finding may lead to serious research towards developing new and efficient drugs for diabetes.

Systematic Comparison of Dendritic Cell-based Immunotherapeutic Strategies for Malignant Gliomas: In Vitro Induction of Cytolytic and Natural Killer-like T Cells

OBJECTIVE

To compare the efficacy of various immunotherapeutic strategies of loading dendritic cells (DCs) with whole-glioma cell antigens and characterize the effector responses induced.

METHODS

DCs were either fused with major histocompatibility complex (MHC)-matched glioma cells (Fusion) or pulsed with apoptotic tumor cells (DC/Apo), total tumor ribonucleic acid (RNA) (DC/RNA), or tumor lysate (DC/Lys). These tumor-DC preparations were then assessed for their phenotype, cytokine profile, and capacity to stimulate autologous peripheral blood mononuclear cells (PBMCs) in vitro. Phenotype and tumor-specific cytolytic activities of various effector cell populations were characterized and compared.

RESULTS

The various tumor-DC preparations exhibited similar phenotype and cytokine profiles irrespective of the method of loading tumor-cell antigens. However, the fusion, DC/Apo, and DC/RNA induced superior tumor cytolytic activities in PBMCs compared with DC/Lys or DC and tumor controls. DC/Apo induced the greatest expansion of tumor-specific lymphocytes, as detected by trypan blue exclusion and thymidine incorporation assays. Flow cytometric analyses also revealed the highest relative percentages of T helper cells (CD3+CD4+), cytotoxic T lymphocytes (CTLs) (CD3+CD8+), and natural killer (NK)-like T cells (CD3+CD56+) in the DC/Apo group among all the groups studied, indicating that DC/Apo induced expansion of PBMCs bearing multiple T and NK cell markers. Interestingly, isolated NK-like T cells demonstrated significantly higher tumor cytotoxicity compared with CTLs isolated from the same groups and was also non-MHC-restricted.

CONCLUSION

Apoptotic tumor cells may be an optimal source of whole-tumor-cell antigen for immunotherapy of gliomas. The study also demonstrates for the first time that both CTLs and NK-like T cells are expanded and stimulated by mature, tumor-pulsed DCs.

Dendritic Cell-Based Immunotherapy of Malignant Gliomas

The failure of conventional treatment modalities for gliomas, in spite of tremendous progress in research in the past two decades, has led to increasing interest in alternative treatment strategies, including immunotherapy. It has become evident that vaccination with dendritic cells (DC), designed to express tumor antigens, is a potent strategy to elicit anti-tumor immune response in both pre-clinical and clinical settings. Various methods have been applied in order to induce DC to express tumor antigens including: pulsing with isolated tumor peptides or whole tumor lysate; fusion with tumor cells; and pulsing with apoptotic tumor cells. Herein, we review the recent progress in DC biology with regard to tumor immunity and discuss current DC-based strategies and future prospects in immunotherapy for malignant gliomas.

Human autologous dendritic cell-glioma fusions: feasibility and capacity to stimulate T cells with proliferative and cytolytic activity

Gliomas are the most common primary neoplasm of the central nervous system. The failure of conventional treatment modalities to improve outcome over the last two decades has led to interest in alternative treatment modalities. Dendritic cell (DC)-based immunotherapy has utilized DC pulsed with tumor lysate or peptide to induce an antitumor immune response mediated largely by CD8 T cells. While this has been effective in preclinical studies, clinical efficacy remains unproven. Recently, hybrid cells produced by fusions of tumor and autologous DC have demonstrated remarkable efficacy for stimulating an anti-tumor immune response in both preclinical and clinical studies of extra-cranial neoplasms. The advantage of generating such hybrid cells is that the entire cellular material of the tumor is processed and presented in both endogenous and exogenous pathways. This leads to activation of both MHC class I restricted CD8 cells as well as MHC class II restricted CD4 T cells. Here, we examined in vitro T cell stimulatory capacity of autologous human DC-glioma fusion in comparison to DC loaded with apoptotic glioma. DC fused with autologous tumor or loaded with apoptotic tumor cells (DC/apo) were first used to stimulate autologous non-adherent peripheral blood mononuclear cells (PBMC), in vitro. The PBMC were then examined for phenotype (CD3, CD4, CD8) and intracellular IFN-gamma using flow cytometry. Lymphocyte proliferation and cytolytic responses were also assessed. Lymphocytes stimulated in vitro with fusion or DC/apo cells showed significantly enhanced cytotoxicity and proliferation against autologous tumor cells compared with PBMC stimulated with tumor cells or DC alone. Both strategies had similar efficacy. Tumor-cytolytic responses were enhanced by the addition of CD40 ligand (CD40L), and partially blocked by anti-MHC class I antibody. Flow cytometric analysis detected CD3+ CD8+ T cells, which also stained positive for intracellular IFN-gamma. The study suggests that DC/glioma fusion and DC/apo have comparable efficacy for stimulation of CTL with cytolytic and proliferative activity against human malignant gliomas. These findings may have implications for future studies of DC-based immunotherapy in malignant gliomas.

Regional, but not systemic recruitment/expansion of dendritic cells by a pluronic-formulated Flt3-ligand plasmid with vaccine adjuvant activity

Regional recruitment of dendritic cells (DCs) by the local administration of granulocyte macrophage-colony stimulating factor (GM-CSF) or Flt3-ligand (Flt3L) has vaccine adjuvant activity. However, Flt3L, with its DC growth factor activity, has not been extensively studied as a vaccine adjuvant, particularly as a plasmid vector. We report that the intramuscular (IM) injection of a Flt3L plasmid (pNGVL-hFlex), when formulated in a pluronic carrier (SP1017, Supratek Pharma, Inc., Laval, Que., Canada), recruits DC to the injection site and regional lymph nodes (LNs) and augments immune responses to a p17 HIV plasmid vaccine to a greater extent than the injection of a naked DNA vaccine alone. Following IM administration of pNGVL-hFlex, Flt3L mRNA, Flt3L protein and infiltrating DC accumulate at the injection site. The number of DC in the draining LNs are also significantly increased with the greatest increase observed following injection of 2.5 microg of pNGVL-hFlex formulated in 0.01% SP1017. Flow cytometric studies demonstrate that the LN-infiltrating DC is mainly of the CD11c(+)CD11b(-) phenotype (IL-12 producing). Further, the co-injection of pNGVL3-hFlex and p17 HIV plasmids, formulated in SP1017, significantly increases the immune responses to the plasmid vaccine (pVAX-gag). The co-injection of pVAX-gag and pNGVL3-hFlex, formulated in SP1017, significantly increase delayed-type hypersensitivity responses and the numbers of antigen (Ag)-specific interferon-gamma secreting T cells in the spleen (Enzyme Linked Immune Spot (ELISpot) assay), compared to mice immunized with pVAX-gag formulated in SP1017 alone. We conclude that the IM injection of pNGVL-hFlex with SP1017 can increase the number of DC in draining LN and at the site of injection, thereby providing adjuvant activity for a plasmid vaccine resulting in a significantly increased, Ag-specific T cell response.

Flt3 ligand augmentation of T cell mitogenesis and expansion of type 1 effector/memory T cells

Herein we report mechanisms whereby Flt3 ligand (FL) augments steady state T cell activity in addition to the expansion of dendritic cells (DCs). We demonstrate that in vivo administration of FL increases the frequency and absolute number of effector/memory T cells and preferentially expands T cells that express a type-1 cytokine phenotype. In addition, FL enhances T cell proliferative responses to Concanavalin A that directly correlated with increased frequencies in effector/memory T cells and expansion of lymphoid-derived (type 1) DCs (DC1s). Together, these data demonstrate that mechanisms of FL-induced T cell regulation include not only the expansion of DC subsets, but also the preferential expansion of type 1 -effector/memory T cell populations, and suggest multiple mechanisms of action for FL as a vaccine adjuvant and as a therapeutic modality.

Flt3 ligand and conjugation to IL-1beta peptide as adjuvants for a type 1, T-cell response to an HIV p17 gag vaccine

The adjuvant activity of Flt3 ligand (Flt3L) and conjugation to an interleukin (IL)-1beta bioactive fragment were compared, either alone or in combination, for their ability to induce T- and B-cell responses to the HGP-30 peptide sequence (amino acids 86-115 of human immunodeficiency virus (HIV) gag p17). The efficiency of HGP-30/IL-1beta conjugation, Flt3L administration or both as adjuvants was examined and all were found to augment similar levels of delayed type hypersensitivity (DTH) responses. In contrast, significant antigen (Ag)-specific types 1 and 2 T-cell ELISPOT responses were induced only by the combination of adjuvants. Further, in vitro sensitization with HGP-30 selectively increased Ag-specific, type 1 T-cell and cytotoxic T lymphocyte (CTL) responses to HGP-30-derived nonapeptide epitopes, while type 2 responses declined as measured in the ELISPOT assay. No serum antibodies to HGP-30 were induced unless HGP-30 was conjugated to keyhole-limpet hemocyanin. This suggests that a combination adjuvant strategy using Flt3L and conjugation to a biologically active IL-1beta fragment may be used to preferentially increase type 1 T-cell and CTL responses to HIV-1 gag antigenic epitopes.

Immunization with wild-type p53 gene sequences coadministered with Flt3 ligand induces an antigen-specific type 1 T-cell response

We examined the ability of immunization with sequential adenovirus/plasmid DNA vectors expressing human wild-type p53 to stimulate a type 1 T-cell response and induce protection against challenge from a metastatic tumor that expresses mutated murine p53. We found that tumor protection and an antigen (Ag)-specific immune response were enhanced by prior injection of Flt3 ligand (Flt3L) at a dose and schedule that significantly increased dendritic cell (DC) number and frequency. Preliminary studies using enzyme-linked immunospot and Winn assays suggested that Ag-specific CD8 cells, with their significant increase in IFN-gamma-secreting activity (Tc1 cells), were responsible for the tumor protection. The delayed-type hypersensitivity response to p53 was increased in mice immunized with p53 alone or p53 and Flt3L compared with a negative control. In contrast, spleen cells from mice immunized with p53 and Flt3L exhibited a higher Ag-specific proliferative response than mice immunized with p53 alone. The frequencies of Ag-specific IFN-gamma and interleukin (IL)-4-secreting cells were determined using an enzyme-linked immunospot assay, which demonstrated that the frequency of IFN-gamma-secreting cells was significantly higher in mice immunized with p53 and Flt3L than in mice receiving Flt3L, excipient, or p53 treatment alone. In contrast, the frequency of IL-4-secreting cells did not differ significantly among these groups. We also observed an increased frequency of IL-12 and IFN-gamma-secreting cells (but not IL-4 or IL-10) in the spleens of mice immediately after 10 days of Flt3L treatment, which was also the day of p53 priming. This observation supports the likelihood that there are multiple mechanisms of Flt3L adjuvant activity, including expansion of DC and type 1 T-cell number. Overall, these results suggest that immunization with p53 genetic sequences after in vivo expansion of DC, using Flt3L, provides a useful strategy to induce p53-specific, and protective, type 1 T-cell responses.

Flt3 ligand and granulocyte-macrophage colony-stimulating factor preferentially expand and stimulate different dendritic and T-cell subsets

OBJECTIVE

Mechanisms of T-cell stimulation by Flt3 ligand (Flt3L) and granulocyte-macrophage colony-stimulating factor (GM-CSF) remain unclear. Herein, we compared the effects of Flt3L and GM-CSF on the expansion of dendritic cells (DC) and T-cell subsets and cytokine expression.

METHODS

Naïve and effector/memory T cells were analyzed by flow cytometry (FC). CD4(+) and CD8(+) T cells and CD11c(+)CD11b(dull/-)(DC1) and CD11c(+)CD11b(+) (DC2) subsets were isolated and the frequency of IFN-gamma-, IL-12- (type 1) and IL-4-, IL-10 (type 2)-producing cells and cytokine mRNA expression evaluated.

RESULTS

Flt3L expanded both DC1 and DC2 subsets with a significantly higher percentage and number of DC1 than DC2, while GM-CSF preferentially expanded the DC2 subset. Isolated DC1 from Flt3L-injected mice had significantly higher levels of IL-12 (p40) than IL-10, while the converse occurred with DC2. The numbers of naïve and memory T cells were elevated in mice that received Flt3L or GM-CSF. However, the number of memory CD4(+) and CD8(+) T cells was significantly increased in Flt3L as compared to GM-CSF cohorts. While GM-CSF increased the frequency of both type 1 and type 2 cytokine-producing cells, Flt3L significantly augmented the frequency of type 1 T cells.

CONCLUSIONS

In contrast to GM-CSF, Flt3L preferentially induces the expansion of type 1 T cells. The mechanism of Flt3L-induced T-cell stimulation is associated with the expansion of the IL-12 (p40)-producing DC1 and memory T cells.