Microglia-targeted inhibition of miR-17 via mannose-coated lipid nanoparticles improves pathology and behavior in a mouse model of Alzheimer's disease

Neuroinflammation and accumulation of Amyloid Beta (Aβ) accompanied by deterioration of special memory are hallmarks of Alzheimer's disease (AD). Effective preventative and treatment options for AD are still needed. Microglia in AD brains are characterized by elevated levels of microRNA-17 (miR-17), which is accompanied by defective autophagy, Aβ accumulation, and increased inflammatory cytokine production. However, the effect of targeting miR-17 on AD pathology and memory loss is not clear. To specifically inhibit miR-17 in microglia, we generated mannose-coated lipid nanoparticles (MLNPs) enclosing miR-17 antagomir (Anti-17 MLNPs), which are targeted to mannose receptors readily expressed on microglia. We used a 5XFAD mouse model (AD) that recapitulates many AD-related phenotypes observed in humans. Our results show that Anti-17 MLNPs, delivered to 5XFAD mice by intra-cisterna magna injection, specifically deliver Anti-17 to microglia. Anti-17 MLNPs downregulated miR-17 expression in microglia but not in neurons, astrocytes, and oligodendrocytes. Anti-17 MLNPs attenuated inflammation, improved autophagy, and reduced Aβ burdens in the brains. Additionally, Anti-17 MLNPs reduced the deterioration in spatial memory and decreased anxiety-like behavior in 5XFAD mice. Therefore, targeting miR-17 using MLNPs is a viable strategy to prevent several AD pathologies. This selective targeting strategy delivers specific agents to microglia without the adverse off-target effects on other cell types. Additionally, this approach can be used to deliver other molecules to microglia and other immune cells in other organs.

Low-dose Paclitaxel with Pembrolizumab Enhances Clinical and Immunologic Responses in Platinum-refractory Urothelial Carcinoma

PURPOSE

Single-agent checkpoint inhibition is effective in a minority of patients with platinum-refractory urothelial carcinoma; therefore, the efficacy of combining low-dose paclitaxel with pembrolizumab was tested.

MATERIALS AND METHODS

This was a prospective, single-arm phase II trial with key inclusion criteria of imaging progression within 12 months of platinum therapy and Eastern Cooperative Oncology Group ≤1. Treatment was pembrolizumab 200 mg day 1 and paclitaxel 80 mg/m2 days 1 and 8 of a 21-day cycle for up to eight cycles unless progression or unacceptable adverse events (AE). The primary endpoint was overall response rate (ORR) with overall survival (OS), 6-month progression-free survival (PFS), and safety as key secondary endpoints. Change in circulating immune cell populations, plasma, and urinary miRs were evaluated.

RESULTS

Twenty-seven patients were treated between April 2016 and June 2020, with median follow-up of 12.4 months. Baseline median age was 68 years, with 81% men and 78% non-Hispanic White. ORR was 33% by intention to treat and 36% in imaging-evaluable patients with three complete responses. Six-month PFS rate was 48.1% [95% confidence interval (CI): 28.7-65.2] and median OS 12.4 months (95% CI: 8.7 months to not reached). Common ≥ grade 2 possibly-related AEs were anemia, lymphopenia, hyperglycemia, and fatigue; grade 3/4 AEs occurred in 56%, including two immune-mediated AEs (pneumonitis and nephritis). Responding patients had a higher percentage of circulating CD4+IFNγ+ T cells. Levels of some miRs, including plasma miR 181 and miR 223, varied in responders compared with nonresponders.

CONCLUSIONS

The addition of low-dose paclitaxel to pembrolizumab is active and safe in platinum-refractory urothelial carcinoma.

SIGNIFICANCE

We found that combining pembrolizumab with low-dose paclitaxel may be effective in patients with urothelial carcinoma progressing on platinum chemotherapy, with favorable safety profiles.

Opposing effects of acellular and whole cell pertussis vaccines on Bordetella pertussis biofilm formation, Siglec-F+ neutrophil recruitment and bacterial clearance in mouse nasal tissues

Despite global vaccination, pertussis caused by Bordetella pertussis (Bp) is resurging. Pertussis resurgence is correlated with the switch from whole cell vaccines (wPV) that elicit TH1/TH17 polarized immune responses to acellular pertussis vaccines (aPV) that elicit primarily TH2 polarized immune responses. One explanation for the increased incidence in aPV-immunized individuals is the lack of bacterial clearance from the nose. To understand the host and bacterial mechanisms that contribute to Bp persistence, we evaluated bacterial localization and the immune response in the nasal associated tissues (NT) of naïve and immunized mice following Bp challenge. Bp resided in the NT of unimmunized and aPV-immunized mice as biofilms. In contrast, Bp biofilms were not observed in wPV-immunized mice. Following infection, Siglec-F+ neutrophils, critical for eliminating Bp from the nose, were recruited to the nose at higher levels in wPV immunized mice compared to aPV immunized mice. Consistent with this observation, the neutrophil chemokine CXCL1 was only detected in the NT of wPV immunized mice. Importantly, the bacteria and immune cells were primarily localized within the NT and were not recovered by nasal lavage (NL). Together, our data suggest that the TH2 polarized immune response generated by aPV vaccination facilitates persistence in the NT by impeding the infiltration of immune effectors and the eradication of biofilms In contrast, the TH1/TH17 immune phenotype generated by wPV, recruits Siglec-F+ neutrophils that rapidly eliminate the bacterial burden and prevent biofilm establishment. Thus, our work shows that aPV and wPV have opposing effects on Bp biofilm formation in the respiratory tract and provides a mechanistic explanation for the inability of aPV vaccination to control bacterial numbers in the nose and prevent transmission.

Genome-based prediction of cross-protective, HLA-DR-presented epitopes as putative vaccine antigens for multiple Bordetella species

IMPORTANCE

Pertussis, caused by Bordetella pertussis, can cause debilitating respiratory symptoms, so whole-cell pertussis vaccines (wPVs) were introduced in the 1940s. However, reactogenicity of wPV necessitated the development of acellular pertussis vaccines (aPVs) that were introduced in the 1990s. Since then, until the COVID-19 pandemic began, reported pertussis incidence was increasing, suggesting that aPVs do not induce long-lasting immunity and may not effectively prevent transmission. Additionally, aPVs do not provide protection against other Bordetella species that are observed during outbreaks. The significance of this work is in determining potential new vaccine antigens for multiple Bordetella species that are predicted to elicit long-term immune responses. Genome-based approaches have aided the development of novel vaccines; here, these methods identified Bordetella vaccine candidates that may be cross-protective and predicted to induce strong memory responses. These targets can lead to an improved vaccine with a strong safety profile while also strengthening the longevity of the immune response.

A next-generation intranasal trivalent MMS vaccine induces durable and broad protection against SARS-CoV-2 variants of concern

As SARS-CoV-2 variants of concern (VoCs) that evade immunity continue to emerge, next-generation adaptable COVID-19 vaccines which protect the respiratory tract and provide broader, more effective, and durable protection are urgently needed. Here, we have developed one such approach, a highly efficacious, intranasally delivered, trivalent measles-mumps-SARS-CoV-2 spike (S) protein (MMS) vaccine candidate that induces robust systemic and mucosal immunity with broad protection. This vaccine candidate is based on three components of the MMR vaccine, a measles virus Edmonston and the two mumps virus strains [Jeryl Lynn 1 (JL1) and JL2] that are known to provide safe, effective, and long-lasting protective immunity. The six proline-stabilized prefusion S protein (preS-6P) genes for ancestral SARS-CoV-2 WA1 and two important SARS-CoV-2 VoCs (Delta and Omicron BA.1) were each inserted into one of these three viruses which were then combined into a trivalent "MMS" candidate vaccine. Intranasal immunization of MMS in IFNAR1-/- mice induced a strong SARS-CoV-2-specific serum IgG response, cross-variant neutralizing antibodies, mucosal IgA, and systemic and tissue-resident T cells. Immunization of golden Syrian hamsters with MMS vaccine induced similarly high levels of antibodies that efficiently neutralized SARS-CoV-2 VoCs and provided broad and complete protection against challenge with any of these VoCs. This MMS vaccine is an efficacious, broadly protective next-generation COVID-19 vaccine candidate, which is readily adaptable to new variants, built on a platform with a 50-y safety record that also protects against measles and mumps.

Systemic priming and intranasal booster with a BcfA-adjuvanted acellular pertussis vaccine generates CD4+ IL-17+ nasal tissue resident T cells and reduces B. pertussis nasal colonization

Introduction

Resurgence of pertussis, caused by Bordetella pertussis, necessitates novel vaccines and vaccination strategies to combat this disease. Alum-adjuvanted acellular pertussis vaccines (aPV) delivered intramuscularly reduce bacterial numbers in the lungs of immunized animals and humans, but do not reduce nasal colonization. Thus, aPV-immunized individuals are sources of community transmission. We showed previously that modification of a commercial aPV (Boostrix) by addition of the Th1/17 polarizing adjuvant Bordetella Colonization Factor A (BcfA) attenuated Th2 responses elicited by alum and accelerated clearance of B. pertussis from mouse lungs. Here we tested whether a heterologous immunization strategy with systemic priming and mucosal booster (prime-pull) would reduce nasal colonization.

Methods

Adult male and female mice were immunized intramuscularly (i.m.) with aPV or aPV/BcfA and boosted either i.m. or intranasally (i.n.) with the same formulation. Tissue-resident memory (TRM) responses in the respiratory tract were quantified by flow cytometry, and mucosal and systemic antibodies were quantified by ELISA. Immunized and naïve mice were challenged i.n. with Bordetella pertussis and bacterial load in the nose and lungs enumerated at days 1-14 post-challenge.

Results

We show that prime-pull immunization with Boostrix plus BcfA (aPV/BcfA) generated IFNγ+ and IL-17+ CD4+ lung resident memory T cells (TRM), and CD4+IL-17+ TRM in the nose. In contrast, aPV alone delivered by the same route generated IL-5+ CD4+ resident memory T cells in the lungs and nose. Importantly, nasal colonization was only reduced in mice immunized with aPV/BcfA by the prime-pull regimen.

Conclusions

These results suggest that TH17 polarized TRM generated by aPV/BcfA may reduce nasal colonization thereby preventing pertussis transmission and subsequent resurgence.

Prime-Pull Immunization of Mice with a BcfA-Adjuvanted Vaccine Elicits Sustained Mucosal Immunity That Prevents SARS-CoV-2 Infection and Pathology

Vaccines against SARS-CoV-2 that induce mucosal immunity capable of preventing infection and disease remain urgently needed. In this study, we demonstrate the efficacy of Bordetella colonization factor A (BcfA), a novel bacteria-derived protein adjuvant, in SARS-CoV-2 spike-based prime-pull immunizations. We show that i.m. priming of mice with an aluminum hydroxide- and BcfA-adjuvanted spike subunit vaccine, followed by a BcfA-adjuvanted mucosal booster, generated Th17-polarized CD4+ tissue-resident memory T cells and neutralizing Abs. Immunization with this heterologous vaccine prevented weight loss following challenge with mouse-adapted SARS-CoV-2 (MA10) and reduced viral replication in the respiratory tract. Histopathology showed a strong leukocyte and polymorphonuclear cell infiltrate without epithelial damage in mice immunized with BcfA-containing vaccines. Importantly, neutralizing Abs and tissue-resident memory T cells were maintained until 3 mo postbooster. Viral load in the nose of mice challenged with the MA10 virus at this time point was significantly reduced compared with naive challenged mice and mice immunized with an aluminum hydroxide-adjuvanted vaccine. We show that vaccines adjuvanted with alum and BcfA, delivered through a heterologous prime-pull regimen, provide sustained protection against SARS-CoV-2 infection.

Architecture and matrix assembly determinants of Bordetella pertussis biofilms on primary human airway epithelium

Traditionally, whooping cough or pertussis caused by the obligate human pathogen Bordetella pertussis (Bp) is described as an acute disease with severe symptoms. However, many individuals who contract pertussis are either asymptomatic or show very mild symptoms and yet can serve as carriers and sources of bacterial transmission. Biofilms are an important survival mechanism for bacteria in human infections and disease. However, bacterial determinants that drive biofilm formation in humans are ill-defined. In the current study, we show that Bp infection of well-differentiated primary human bronchial epithelial cells leads to formation of bacterial aggregates, clusters, and highly structured biofilms which are colocalized with cilia. These findings mimic observations from pathological analyses of tissues from pertussis patients. Distinct arrangements (mono-, bi-, and tri-partite) of the polysaccharide Bps, extracellular DNA, and bacterial cells were visualized, suggesting complex heterogeneity in bacteria-matrix interactions. Analyses of mutant biofilms revealed positive roles in matrix production, cell cluster formation, and biofilm maturity for three critical Bp virulence factors: Bps, filamentous hemagglutinin, and adenylate cyclase toxin. Adherence assays identified Bps as a new Bp adhesin for primary human airway cells. Taken together, our results demonstrate the multi-factorial nature of the biofilm extracellular matrix and biofilm development process under conditions mimicking the human respiratory tract and highlight the importance of model systems resembling the natural host environment to investigate pathogenesis and potential therapeutic strategies.

Development of carbohydrate based next-generation anti-pertussis vaccines

Pertussis is a highly contagious respiratory disease caused by the Gram-negative bacterial pathogen, Bordetella pertussis. Despite high global vaccination rates, pertussis is resurging worldwide. Here we discuss the development of current pertussis vaccines and their limitations, which highlight the need for new vaccines that can protect against the disease and prevent development of the carrier state, thereby reducing transmission. The lipo-oligosaccharide of Bp is an attractive antigen for vaccine development as the anti-glycan antibodies could have bactericidal activities. The structure of the lipo-oligosaccharide has been determined and its immunological properties analyzed. Strategies enabling the expression, isolation, and bioconjugation have been presented. However, obtaining the saccharide on a large scale with high purity remains one of the main obstacles. Chemical synthesis provides a complementary approach to accessing the carbohydrate epitopes in a pure and structurally well-defined form. The first total synthesis of the non-reducing end pertussis pentasaccharide is discussed. The conjugate of the synthetic glycan with a powerful immunogenic carrier, bacteriophage Qβ, results in high levels and long-lasting anti-glycan IgG antibodies, paving the way for the development of a new generation of anti-pertussis vaccines with high bactericidal activities and biocompatibilities.

A highly efficacious live attenuated mumps virus-based SARS-CoV-2 vaccine candidate expressing a six-proline stabilized prefusion spike

With the rapid increase in SARS-CoV-2 cases in children, a safe and effective vaccine for this population is urgently needed. The MMR (measles/mumps/rubella) vaccine has been one of the safest and most effective human vaccines used in infants and children since the 1960s. Here, we developed live attenuated recombinant mumps virus (rMuV)-based SARS-CoV-2 vaccine candidates using the MuV Jeryl Lynn (JL2) vaccine strain backbone. The soluble prefusion SARS-CoV-2 spike protein (preS) gene, stablized by two prolines (preS-2P) or six prolines (preS-6P), was inserted into the MuV genome at the P-M or F-SH gene junctions in the MuV genome. preS-6P was more efficiently expressed than preS-2P, and preS-6P expression from the P-M gene junction was more efficient than from the F-SH gene junction. In mice, the rMuV-preS-6P vaccine was more immunogenic than the rMuV-preS-2P vaccine, eliciting stronger neutralizing antibodies and mucosal immunity. Sera raised in response to the rMuV-preS-6P vaccine neutralized SARS-CoV-2 variants of concern, including the Delta variant equivalently. Intranasal and/or subcutaneous immunization of IFNAR1-/- mice and golden Syrian hamsters with the rMuV-preS-6P vaccine induced high levels of neutralizing antibodies, mucosal immunoglobulin A antibody, and T cell immune responses, and were completely protected from challenge by both SARS-CoV-2 USA-WA1/2020 and Delta variants. Therefore, rMuV-preS-6P is a highly promising COVID-19 vaccine candidate, warranting further development as a tetravalent MMR vaccine, which may include protection against SARS-CoV-2.

Assessment of front-line healthcare workers' Knowledge, Attitude and Practice after several months of COVID-19 pandemic

BACKGROUND

Frontline healthcare workers (F-HCWs) are at the forefront of medical care providers against the novel coronavirus 2019 (COVID-19) pandemic which has life-threatening potentials. Inadequate knowledge and incorrect attitudes among HCWs can directly influence practices and lead to delayed diagnosis, poor infection control practices, and spread of disease.

OBJECTIVES

The aim of this study was to assess the knowledge, attitude and practice (KAP) regarding the COVID-19 pandemic among the frontline healthcare workers (F-HCWs) working at a tertiary care hospital situated in eastern Uttar Pradesh and to identify the factors significantly associated with KAP.

METHODS

A cross-sectional study was conducted among 260 health care providers across eastern Uttar Pradesh including Basti city during December 2020. Data was collected using a self-primed pretested questionnaire from the FHCWs working at a tertiary care hospital of eastern Uttar Pradesh. In this survey, a convenience sampling method was adopted. 12 items on knowledge, 10 items on attitude, and 5 items on practices related to COVID-19. The other variables consisted of 4 items on socio-demographic attributes, p-value and 95% confidence intervals (CIs) were performed to assess the attitude and practices in relation to knowledge.

RESULTS

Of the total 260 study population, 228 were interviewed online, 32 were self-administered. Knowledge and attitude of the nursing staff were highest but practice score was best for residents. Among different age groups knowledge, attitude and practices scores were highest for 35-45, 45-60 and 25-35 age groups respectively. Respondents having 5-10 years of experience had the best knowledge and the attitude score was highest for HCWs having 10-20 years' experience but the practice score was higher for HCWs having more than 20 years' work experience. Overall knowledge score of respondents having strong correlation with attitude (p<0.05) and to the practice (p<0.05).

CONCLUSION

In this survey many F-HCWs reported adequate overall knowledge with a positive attitude and adopted appropriate practices. The F-HCWs with a higher level of education and more years of experience in health care facilities had better KAP towards COVID-19.

Overcoming Waning Immunity in Pertussis Vaccines: Workshop of the National Institute of Allergy and Infectious Diseases

Despite high vaccine coverage in many parts of the world, pertussis is resurging in a number of areas in which acellular vaccines are the primary vaccine administered to infants and young children. This is attributed in part to the suboptimal and short-lived immunity elicited by acellular pertussis vaccines and to their inability to prevent nasal colonization and transmission of the etiologic agent Bordetella pertussis In response to this escalating public health concern, the National Institute of Allergy and Infectious Diseases held the workshop "Overcoming Waning Immunity in Pertussis Vaccines" in September 2019 to identify issues and possible solutions for the defects in immunity stimulated by acellular pertussis vaccines. Discussions covered aspects of the current problem, gaps in knowledge and possible paths forward. This review summarizes presentations and discussions of some of the key points that were raised by the workshop.

Single-arm phase II study of low-dose paclitaxel and pembrolizumab in platinum-refractory metastatic urothelial carcinoma (UC)

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Background: Single agent checkpoint inhibition is effective in a small proportion of platinum-refractory UC patients but improvements are needed. UC is highly inflammatory, and low-dose chemotherapy may enhance the response to immunotherapy. We evaluated whether combination therapy with low-dose paclitaxel and pembrolizumab is more efficacious than single-agent pembrolizumab which had an objective response rate (ORR) of 21% in a similar patient population in the KEYNOTE-045 study. We also incorporated multiple novel biomarker studies to explore immune regulatory mechanisms in UC. Methods: This is a prospective, single-arm phase II trial (NCT02581982) of pembrolizumab combined with low-dose paclitaxel in patients with platinum-refractory metastatic UC. Key inclusion criteria included measurable progression of disease within 12 months of platinum therapy and ECOG ≤1. Patients received pembrolizumab 200mg day 1 and paclitaxel 80 mg/m2 days 1 and 8 of a 21 day cycle for up to 8 cycles unless clinical or radiographic disease progression or unacceptable adverse events (AEs) were observed. Responding patients could remain on pembrolizumab maintenance for up to 2 years. The primary endpoint was ORR; key secondary endpoints included overall survival (OS), 6-month progression free survival (PFS), and safety. Results: Twenty-seven patients were treated between 4/2016 - 6/2020, with a median follow up of 9.9 months. At baseline, the median age was 68 years (range 49-80), with 81% men and 78% non-Hispanic white. The majority (59%) were ECOG 1. Twenty-one of 27 (78%) received prior definitive therapy: chemoradiation in 24% and surgery in 76%. The majority (78%) of patients received prior cisplatin. 70% progressed on a cisplatin-based regimen while 30% progressed on carboplatin-based regimen within 12 months of study entry. The ORR by intention to treat was 9 of 27 patients (33%) and in patients evaluable for response by imaging was 9 of 25 (36%), including 3 with complete response. Disease control rate in evaluable patients was 72%. Six-month PFS was 46.8% (95% CI: 27.2%, 64.2%) and median OS was 11.7 months (95% CI: 8.7 mo, NR). Common ≥ grade 2 AEs were anemia (44%), lymphopenia (37%), hyperglycemia (33%), and fatigue (33%). Possible treatment-related at least grade 3 or 4 AEs occurred in 56% of subjects, including 2 immune-mediated AEs (pneumonitis and nephritis) resulting in therapy cessation but a durable partial response. There were no grade 5 events. Conclusions: This study illustrates that the addition of low-dose paclitaxel to pembrolizumab improves outcomes in patients with platinum-refractory UC, relative to single-agent pembrolizumab. No unanticipated safety signals emerged. Exploratory analyses including PDL1 status, tumor mutational burden, and change in circulating microRNAs and in immune cell populations are ongoing. Clinical trial information: NCT02581982.

Neurodevelopmental outcome of healthy term newborn with serum bilirubin >15 mg/dl at one year

BACKGROUND

Neonatal hyperbilirubinemia is a common medical emergency in early neonatal period. Unconjugated bilirubin is neurotoxic and can lead to lifelong neurological sequelae in survivors.

OBJECTIVE

To find out the association between serum bilirubin and neurodevelopmental outcome at 1 year of age using Development Assessment Scale for Indian Infants (DASII).

METHODS

A prospective cohort study was conducted in the Department of Pediatrics of a tertiary care institution of Central India between January 2018 and August 2019. Total 108 term healthy neonates, with at least one serum bilirubin value of >15 mg/dl, were included. Subjects were divided into three groups based on the serum bilirubin; group 1: (15-20 mg/dl) -85(78.7%) cases, group 2: (20-25 mg/dl) -17(15.7%), and group 3: (>25 mg/dl) -6(5.5%). Developmental assessment was done using DASII at 3, 6, 9, 12 months of age.

RESULTS

Out of 108 cases, 101(93.5%) received phototherapy, and 7(6.5%) received double volume exchange transfusion. Severe delay was observed in 5(4.6%) and mild delay in 2(1.9%) cases in the motor domain of DASII at one year. Severe delay in the motor domain was associated with mean TSB of 27.940±2.89 mg/dl and mild delay with mean TSB of 22.75±1.76 mg/dl (p = 0.001). On cluster analysis, delay was observed in locomotion 1 score in 11(13%) cases (p = 0.003) and manipulation score in 6(7.1%) cases in group 1.

CONCLUSION

Increased serum bilirubin was a significant risk factor for the delayed neurodevelopment in babies with neonatal jaundice. Even a moderate level of bilirubin significantly affects the developmental outcome.

A listeriolysin O subunit vaccine is protective against Listeria monocytogenes

Listeria monocytogenes is a facultative intracellular pathogen responsible for the life-threatening disease listeriosis. The pore-forming toxin listeriolysin O (LLO) is a critical virulence factor that plays a major role in the L. monocytogenes intracellular lifecycle and is indispensable for pathogenesis. LLO is also a dominant antigen for T cells involved in sterilizing immunity and it was proposed that LLO acts as a T cell adjuvant. In this work, we generated a novel full-length LLO toxoid (LLO^T) in which the cholesterol-recognition motif, a threonine-leucine pair located at the tip of the LLO C-terminal domain, was substituted with two glycine residues. We showed that LLO^T lost its ability to bind cholesterol and to form pores. Importantly, LLO^T retained binding to the surface of epithelial cells and macrophages, suggesting that it could efficiently be captured by antigen-presenting cells. We then determined if LLO^T can be used as an antigen and adjuvant to protect mice from L. monocytogenes infection. Mice were immunized with LLO^T alone or together with cholera toxin or Alum as adjuvants. We found that mice immunized with LLO^T alone or in combination with the Th2-inducing adjuvant Alum were not protected against L. monocytogenes. On the other hand, mice immunized with LLO^T along with the experimental adjuvant cholera toxin, were protected against L. monocytogenes, as evidenced by a significant decrease in bacterial burden in the liver and spleen three days post-infection. This immunization regimen elicited mixed Th1, Th2, and Th17 responses, as well as the generation of LLO-neutralizing antibodies. Further, we identified T cells as being required for immunization-induced reductions in bacterial burden, whereas B cells were dispensable in our model of non-pregnant young mice. Overall, this work establishes that LLO^T is a promising vaccine antigen for the induction of protective immunity against L. monocytogenes by subunit vaccines containing Th1-driving adjuvants.

Chemical Synthesis and Immunological Evaluation of a Pentasaccharide Bearing Multiple Rare Sugars as a Potential Anti-pertussis Vaccine

With the infection rate of Bordetella pertussis at a 60-year high, there is an urgent need for new anti-pertussis vaccines. The lipopolysaccharide (LPS) of B. pertussis is an attractive antigen for vaccine development. With the presence of multiple rare sugars and unusual glycosyl linkages, the B. pertussis LPS is a highly challenging synthetic target. In this work, aided by molecular dynamics simulation and modeling, a pertussis-LPS-like pentasaccharide was chemically synthesized for the first time. The pentasaccharide was conjugated with a powerful carrier, bacteriophage Qβ, as a vaccine candidate. Immunization of mice with the conjugate induced robust anti-glycan IgG responses with IgG titers reaching several million enzyme-linked immunosorbent assay (ELISA) units. The antibodies generated were long lasting and boostable and could recognize multiple clinical strains of B. pertussis, highlighting the potential of Qβ-glycan as a new anti-pertussis vaccine.

Evaluation of Host-Pathogen Responses and Vaccine Efficacy in Mice

Vaccines are a 20^th century medical marvel. They have dramatically reduced the morbidity and mortality caused by infectious diseases and contributed to a striking increase in life expectancy around the globe. Nonetheless, determining vaccine efficacy remains a challenge. Emerging evidence suggests that the current acellular vaccine (aPV) for Bordetella pertussis (B. pertussis) induces suboptimal immunity. Therefore, a major challenge is designing a next-generation vaccine that induces protective immunity without the adverse side effects of a whole-cell vaccine (wPV). Here we describe a protocol that we used to test the efficacy of a promising, novel adjuvant that skews immune responses to a protective Th1/Th17 phenotype and promotes a better clearance of a B. pertussis challenge from the murine respiratory tract. This article describes the protocol for mouse immunization, bacterial inoculation, tissue harvesting, and analysis of immune responses. Using this method, within our model, we have successfully elucidated crucial mechanisms elicited by a promising, next-generation acellular pertussis vaccine. This method can be applied to any infectious disease model in order to determine vaccine efficacy.

Intranasal immunization with an acellular pertussis vaccine containing a Th1/17 skewing adjuvant, BcfA, improves B. pertussis clearance from the mouse respiratory tract

Bordetella pertussis is the causative agent of whooping cough, a resurging vaccine-preventable disease. This highly contagious disease is most severe in infants and young children. Current alum-adjuvanted acellular pertussis vaccines (aPV) prevent severe disease but do not prevent nasal carriage and subsequent person-to-person pathogen transmission. The Th1/2 skewed immune response induced by aPV is one potential explanation for this failure. We are testing the hypothesis that modification of current aPV by the addition of an adjuvant, BcfA, that skews immune responses towards the more protective Th1/17 phenotype will improve protection. We also hypothesize that changing the delivery route from intramuscular (i.m) to intranasal (i.n) administration will generate mucosal immunity and further improve protection. In the established mouse model of B. pertussis infection, we found that i.m. immunization of mice with an experimental aPV containing BcfA and alum as the adjuvants significantly reduced bacterial numbers in the lungs compared to an alum-adjuvanted vaccine alone. Further, i.n administration of the BcfA+alum containing vaccine provided better protection against colonization of the trachea and lungs than i.m. immunization. Alum-induced Th2 cytokine responses were reduced by addition of BcfA, and were further reduced by i.n. vaccine delivery. Thus, a revised aPV that includes BcfA, administered i.n, may improve protection against B. pertussis infection compared with current formulations and delivery method.

The effect of stoichiometry on the structural, thermal and electronic properties of thermally decomposed nickel oxide

A thermal decomposition route with different sintering temperatures was employed to prepare non-stoichiometric nickel oxide (Ni_1−δO) from Ni(NO₃)₂·6H₂O as a precursor. The non-stoichiometry of samples was then studied chemically by iodometric titration, wherein the concentration of Ni³⁺ determined by chemical analysis, which is increasing with increasing excess of oxygen or reducing the sintering temperature from the stoichiometric NiO; it decreases as sintering temperature increases. These results were corroborated by the excess oxygen obtained from the thermo-gravimetric analysis (TGA). X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) techniques indicate the crystalline nature, Ni–O bond vibrations and cubic structural phase of Ni_1−δO. The change in oxidation state of nickel from Ni³⁺ to Ni²⁺ were seen in the X-ray photoelectron spectroscopy (XPS) analysis and found to be completely saturated in Ni²⁺ as the sintering temperature reaches 700 °C. This analysis accounts for the implication of non-stoichiometric on the magnetization data, which indicate a shift in antiferromagnetic ordering temperature (T_N) due to associated increased magnetic disorder. A sharp transition in the specific heat capacity at T_N and a shift towards lower temperature are also evidenced with respect to the non-stoichiometry of the system.

A thermal decomposition route with different sintering temperatures was employed to prepare non-stoichiometric nickel oxide (Ni_1−δO) from Ni(NO₃)₂·6H₂O as a precursor.

Gender differential and implications in the epidemiology of stress fractures among cadets of Indian Armed Forces

BACKGROUND

Most studies on stress fractures in India have been carried out among recruits as against officer trainees and limited to males. With the continuous induction of women in the Armed Forces, it was decided to carry out a study among officer trainees of the three services and compare the epidemiology among genders.

METHODS

A prospective study was carried out in 2011-2012 at Training Institutes of the three services where male and female cadets train together. Baseline data was collected for all trainees who joined the academy during the study period. All cadets were followed up for development of stress fractures for which details were taken. Additional information was taken from the Training Institute.

RESULTS

A total of 3220 cadets (2612 male and 608 female cadets) were included in the study. Overall 276 cadets were observed to have stress fractures during training - making an incidence of 6.9% for male cadets and 15.8% for female cadets. Females were found to have a significantly higher incidence of stress fractures. Further the distribution and onset of stress fractures in females was observed to be distinct from males.

CONCLUSION

The significant gender differential observed in the study indicates differential role of intrinsic and extrinsic risk factors in the causation of stress fractures among male and female. Special consideration needs to be given to these while planning and implementing measures for prevention. Further studies may be carried out on subject and on the effect of interventions in stress fracture prevention.

A study on local expression of NF-κB, CCL2 and their involvement in intratumoral macrophage infiltration in breast cancer

NF-κB has been implicated in mechanisms promoting inflammation in tumor microenvironment leading to breast cancer metastasis. Owing to critical role of CCL2 during metastasis, particularly in its capacity to act as a chemoattractant for macrophages and their precursors i.e monocytes, we decided to explore if pro-metastatic function of NF-κB could be attributable to CCL2 and/or macrophage infiltration. Through our study we provide experimental and clinical evidence in support of co-ordinated expression of chemokines CCL2, NF-κB and intratumoral macrophage content particularly with respect to breast cancer, with an additional evidence of these three variables being key determinant for poor prognosis and diminished survival amongst breast cancer patients both independently as well in a coordinated manner. The mean fold increase in mRNA expression level of NF-κB and CCL2 indicated that it was over expressed 13.57 and 13.18 fold respectively in tumor tissue as compared to adjacent normal tissue. Among these Immunohistochemistry expression of CD68 marker showed that 62 patients (66.7%) had low/moderate CD68 expression while 31 patients (33.3%) had strong expression. All three variables viz.NF-κB, CCL2 and CD68 showed significant (p<0.05 or p<0.01 or p<0.001) respectively associations with both clinicopathological (except CD68 with stage) and hormone receptors (ER, PR and Her2/neu) and their co-expressions indicating these as predictors of breast cancer. In this study we decipher the possible molecular mechanism by way of which NF-κB may promote breast cancer metastasis. Our study has clinical relevance as it establishes significance of these three variables as potential predictive markers to be employed in breast cancer.

Bordetella biofilms: a lifestyle leading to persistent infections

Bordetella bronchiseptica and B. pertussis are Gram-negative bacteria that cause respiratory diseases in animals and humans. The current incidence of whooping cough or pertussis caused by B. pertussis has reached levels not observed since the 1950s. Although pertussis is traditionally known as an acute childhood disease, it has recently resurged in vaccinated adolescents and adults. These individuals often become silent carriers, facilitating bacterial circulation and transmission. Similarly, vaccinated and non-vaccinated animals continue to be carriers of B. bronchiseptica and shed bacteria resulting in disease outbreaks. The persistence mechanisms of these bacteria remain poorly characterized. It has been proposed that adoption of a biofilm lifestyle allows persistent colonization of the mammalian respiratory tract. The history of Bordetella biofilm research is only a decade long and there is no single review article that has exclusively focused on this area. We systematically discuss the role of Bordetella factors in biofilm development in vitro and in the mouse respiratory tract. We further outline the implications of biofilms to bacterial persistence and transmission in humans and for the design of new acellular pertussis vaccines.

Opposing effects of androgen ablation on immune function in prostate cancer

Although it is recognized that immune function is modulated by androgen ablation therapy for prostate cancer, the long-term consequences are not completely understood. We recently showed that both effector and inhibitory immune mechanisms are amplified by androgen ablation, providing one explanation for only transient increases in immune function after castration.

Cyclooxygenase-2 inhibition attenuates hypoxic cancer cells induced m2-polarization of macrophages

Tumor-associated macrophages (TAMs), represent a major subpopulation of tumor infiltrating immune cells. These alternatively activated M2-polarized macrophages are well known for their pro-tumor functions. Owing to their established role in potentiating tumor-neovasculogenesis and metastasis, TAMs have emerged as promising target for anti-cancer immunotherapy. One of the key TAMs related phenomenon that is amenable to therapeutic intervention is their phenotype switching into alternatively activated M2-polarized macrophages. Hindering macrophage polarization towards a pro-tumor M2 phenotype, or better still reprogramming the M2 like TAMs towards M1 subtype is being considered a beneficial anti-cancer strategy. Hypoxic tumor milieu has been proposed as one of the most plausible factor governing M2-polarization of macrophages. We recently demonstrated that hypoxic tumor cells imparted a pro—angiogenic M2 skewed phenotype to macrophages. Furthermore, sizeable body of data indicates for participation of cyclooxygenase-2 (COX-2) in macrophage polarization. Concordantly, inhibition of COX-2 is associated with impaired macrophage polarization. Prompted by this in the current study we decided to explore if inhibition of COX-2 activity via chemical inhibitors may prevent hypoxic cancer cell induced M2-polarization of macrophages. We observed that treatment with Flunixin meglumine, an established preferential inhibitor of COX-2 activity markedly inhibited hypoxic cancer cell induced of M2-polarization of macrophages thereby indicating for usage of COX-2 inhibition as possible anti-cancer treatment modality.

Differentially cross-linkable core–shell nanofibers for tunable delivery of anticancer drugs: synthesis, characterization and their anticancer efficacy

This work introduces a new dimension for controlled drug delivery by nanofiber based scaffolds for anticancer therapy.

Interactions between immunity, proliferation and molecular subtype in breast cancer prognosis

BACKGROUND

Gene expression signatures indicative of tumor proliferative capacity and tumor-immune cell interactions have emerged as principal biology-driven predictors of breast cancer outcomes. How these signatures relate to one another in biological and prognostic contexts remains to be clarified.

RESULTS

To investigate the relationship between proliferation and immune gene signatures, we analyzed an integrated dataset of 1,954 clinically annotated breast tumor expression profiles randomized into training and test sets to allow two-way discovery and validation of gene-survival associations. Hierarchical clustering revealed a large cluster of distant metastasis-free survival-associated genes with known immunological functions that further partitioned into three distinct immune metagenes likely reflecting B cells and/or plasma cells; T cells and natural killer cells; and monocytes and/or dendritic cells. A proliferation metagene allowed stratification of cases into proliferation tertiles. The prognostic strength of these metagenes was largely restricted to tumors within the highest proliferation tertile, though intrinsic subtype-specific differences were observed in the intermediate and low proliferation tertiles. In highly proliferative tumors, high tertile immune metagene expression equated with markedly reduced risk of metastasis whereas tumors with low tertile expression of any one of the three immune metagenes were associated with poor outcome despite higher expression of the other two metagenes.

CONCLUSIONS

These findings suggest that a productive interplay among multiple immune cell types at the tumor site promotes long-term anti-metastatic immunity in a proliferation-dependent manner. The emergence of a subset of effective immune responders among highly proliferative tumors has novel prognostic ramifications.

Angiotensin-(1-7) attenuates metastatic prostate cancer and reduces osteoclastogenesis

BACKGROUND

Angiotensin-(1-7) [Ang-(1-7)] is an endogenous, heptapeptide hormone with anti-proliferative and anti-angiogenic properties. The primary objective of this study was to determine whether Ang-(1-7) effectively reduces prostate cancer metastasis in mice.

METHODS

Human PC3 prostate cancer cells were injected into the aortic arch via the carotid artery of SCID mice pre-treated with Ang-(1-7) or injected into the tibia of athymic mice, administered Ang-(1-7) for 5 weeks beginning 2 weeks post-injection. Tumor growth and volume were determined by bioluminescent and magnetic resonance imaging. The presence of tumors was confirmed by hematoxylin and eosin staining; TRAP histochemistry was used to identify osteolytic lesions. The effect of Ang-(1-7) on osteoclastogenesis was assessed in differentiated bone marrow cells.

RESULTS

Pre-treatment with Ang-(1-7) prevented metastatic tumor formation following intra-aortic injection of PC3 cells, while 83% of untreated mice developed tumors in metastatic sites. Circulating VEGF was significantly higher in control mice compared to mice administered Ang-(1-7). A 5-week regimen of the heptapeptide hormone attenuated intra-tibial tumor growth; Ang-(1-7) was significantly higher in the tibia of treated mice than in control animals. Osteoclastogenesis was reduced by 50% in bone marrow cells differentiated in the presence of Ang-(1-7), suggesting that the heptapeptide hormone prevents the formation of osteolytic lesions to reduce tumor survival in the bone microenvironment.

CONCLUSIONS

These findings suggest that Ang-(1-7) may serve as an anti-angiogenic and anti-metastatic agent for advanced prostate cancer. By extension, the heptapeptide hormone may provide effective therapy for bone metastasis produced from primary tumors of the lung and breast.

DNA vector-based RNA interference to study gene function in cancer

RNA interference (RNAi) inhibits gene expression by specifically degrading target mRNAs. Since the discovery of double-stranded small interference RNA (siRNA) in gene silencing, RNAi has become a powerful research tool in gene function studies. Compared to genetic deletion, RNAi-mediated gene silencing possesses many advantages, such as the ease with which it is carried out and its suitability to most cell lines. Multiple studies have demonstrated the applications of RNAi technology in cancer research. In particular, the development of the DNA vector-based technology to produce small hairpin RNA (shRNA) driven by the U6 or H1 promoter has made long term and inducible gene silencing possible. Its use in combination with genetically engineered viral vectors, such as lentivirus, facilitates high efficiencies of shRNA delivery and/or integration into genomic DNA for stable shRNA expression. We describe a detailed procedure using the DNA vector-based RNAi technology to determine gene function, including construction of lentiviral vectors expressing shRNA, lentivirus production and cell infection, and functional studies using a mouse xenograft model. Various strategies have been reported in generating shRNA constructs. The protocol described here employing PCR amplification and a 3-fragment ligation can be used to directly and efficiently generate shRNA-containing lentiviral constructs without leaving any extra nucleotide adjacent to a shRNA coding sequence. Since the shRNA-expression cassettes created by this strategy can be cut out by restriction enzymes, they can be easily moved to other vectors with different fluorescent or antibiotic markers. Most commercial transfection reagents can be used in lentivirus production. However, in this report, we provide an economic method using calcium phosphate precipitation that can achieve over 90% transfection efficiency in 293T cells. Compared to constitutive shRNA expression vectors, an inducible shRNA system is particularly suitable to knocking down a gene essential to cell proliferation. We demonstrate the gene silencing of Yin Yang 1 (YY1), a potential oncogene in breast cancer, by a Tet-On inducible shRNA system and its effects on tumor formation. Research using lentivirus requires review and approval of a biosafety protocol by the Biosafety Committee of a researcher's institution. Research using animal models requires review and approval of an animal protocol by the Animal Care and Use Committee (ACUC) of a researcher's institution.

Increased CD8+ T-cell function following castration and immunization is countered by parallel expansion of regulatory T cells

Although androgen ablation therapy is effective in treating primary prostate cancers, a significant number of patients develop incurable castration-resistant disease. Recent studies have suggested a potential synergy between vaccination and androgen ablation, yet the enhanced T-cell function is transient. Using a defined tumor antigen model, UV-8101-RE, we found that concomitant castration significantly increased the frequency and function of antigen-specific CD8(+) T cells early after the immunization of wild-type mice. However, at a late time point after immunization, effector function was reduced to the same level as noncastrated mice and was accompanied by a concomitant amplification in CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) following immunization. We investigated whether Treg expansion occurred following castration of prostate tumor-bearing mice. In the prostate-specific Pten(-/-) mouse model of prostate cancer, we observed an accelerated Treg expansion in mice bearing the castration-resistant endogenous prostate tumor, which prevented effector responses to UV-8101-RE. Treg depletion together with castration elicited a strong CD8(+) T-cell response to UV-8101-RE in Pten(-/-) mice and rescued effector function in castrated and immunized wild-type mice. In addition, Treg expansion in Pten(-/-) mice was prevented by in vivo interleukin (IL)-2 blockade suggesting that increased IL-2 generated by castration and immunization promotes Treg expansion. Our findings therefore suggest that although effector responses are augmented by castration, the concomitant expansion of Tregs is one mechanism responsible for only transient immune potentiation after androgen ablation.

Reporter gene imaging of immune responses to cancer: progress and challenges

Immune responses to cancer are dynamic processes which take place through the concerted activity of innate and adaptive cell populations. In order to fully understand the efficacy of immune therapies for cancer, it is critical to understand how the treatment modulates the function of each cell type involved in the anti-tumor immune response. Molecular imaging is a versatile method for longitudinal studies of cellular localization and function. The development of reporter genes for tracking cell movement and function was a powerful addition to the immunologist's toolbox. This review will highlight the advances and challenges in the use of reporter gene imaging to track immune cell localization and function in cancer.

Abstract 550: Angiotensin-(1-7) inhibits prostate cancer angiogenesis and metastasis to bone

Prostate cancer is the most frequently diagnosed malignancy and the second-leading cause of cancer death in men. We previously showed that angiotensin-(1-7) [Ang-(1-7)], a seven amino acid peptide hormone, significantly inhibited the growth of human lung cancer cells and tumors, with an associated reduction in angiogenesis. Since previous epidemiological studies suggest that administration of anti-hypertensive drugs which increase Ang-(1-7) reduces the risk of sex-specific cancers, we investigated the effects of the heptapeptide on prostate cancer. Ang-(1-7) markedly reduced human LNCaP prostate tumor xenograft size by 72% in association with a decrease in Ki67 and CD34, markers of tumor proliferation and angiogenesis, respectively. Ang-(1-7) significantly decreased both vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) with a concomitant 12-fold increase in the soluble fraction of VEGF receptor 1 (sFlt-1); sFlt-1 is a decoy receptor that traps PlGF and VEGF, rendering the ligands unavailable to membrane-associated VEGF receptors. Ang-(1-7) also inhibits metastasis of prostate cancer to bone, which is the primary cause of mortality in prostate cancer patients. Human prostate cancer cells were injected into the circulation of SCID mice pretreated with Ang-(1-7), to determine the effect of the heptapeptide on the migration of cells to the metastatic environment. Six weeks following the injection of stably transfected luciferase tagged PC3 (PC3Luc) cells, 5 of the 6 untreated mice developed metastatic bone tumors, measured by bioluminescence and MRI imaging; in contrast, no detectable tumors were observed in mice administered Ang-(1-7). Circulating VEGF was significantly higher in untreated mice compared to mice treated with the heptapeptide. Ang-(1-7) also significantly reduced metastatic tumor formation in athymic mice injected with PC3Luc cells in the tibia as determined by bioluminescence, MRI imaging and immunohistochemistry. Osteolytic lesions as assessed by tartrate resistant acid phosphatase (TRAP) staining were observed surrounding the tibial tumors in control animals. A 50% reduction in osteoclastogenesis was observed when bone marrow cells were differentiated with RANK ligand and colony-stimulating factor in the presence of Ang-(1-7) [from 78.6 ± 8.0 TRAP+-multinucleated cells/field to 33.6 ± 4], suggesting that Ang-(1-7) hinders tumor survival in the bone microenvironment and prevents the formation of osteolytic lesions. Since VEGF is known to facilitate tumor growth and osteolytic disease by enhancing osteoclast survival, the inhibition of VEGF coupled with the reduction in osteoclastogenesis may mediate the inhibition of metastatic skeletal tumor formation. These results suggest that Ang-(1-7) may serve as an anti-proliferative, anti-angiogenic, and anti-metastatic agent for the treatment of prostate cancer that targets the tumor microenvironment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 550. doi:10.1158/1538-7445.AM2011-550

Cough-associated headache in patients with Chiari I malformation: CSF Flow analysis by means of cine phase-contrast MR imaging

The purpose of this study was to analyze the CSF flow in patients with Chiari I to determine differences between patients with and without CAH. Thirty patients with Chiari I malformation underwent cine-PC CSF flow imaging in the sagittal plane. CSF flow pulsations were analyzed by placing regions of interest in the anterior cervical subarachnoid space. Maximum CSF systolic (craniocaudal) and diastolic (caudocranial) velocities as well as the durations of CSF systole and diastole (measured in fractions of the cardiac cycle) were determined. In the region of interest just below the foramen magnum, patients with CAH had a significantly shorter CSF systole and longer diastole (P=.02). A CSF diastolic length of ≥0.75 of the cardiac cycle was 67% sensitive and 86% specific for CAH. Our results indicate that Cine-PC imaging can show differences in CSF flow patterns in patients with Chiari I with and without CAH.

In situ vaccination combined with androgen ablation and regulatory T-cell depletion reduces castration-resistant tumor burden in prostate-specific pten knockout mice

There is no effective treatment for prostate cancer arising after androgen ablation. Previous studies have analyzed the short-term effects of androgen ablation on the immune system and suggest an abatement of immune suppression by hormone removal. Because castration-resistant disease can arise years after treatment, it is crucial to determine the duration of immune potentiation by castration. Because immunotherapeutic efficacy is determined by the balance of immune cell subsets and their location within the tumor, we assessed the acute and chronic effect of androgen ablation on the localization of T-cell subsets within castration-resistant murine prostate cancer. We observed a transient increase in CD4+ and CD8+ T-cell numbers at the residual tumor after androgen ablation. More than 2 months later, regulatory T cells (Treg) were increasingly found within prostate epithelium, whereas CTLs, which were evenly distributed before androgen ablation, became sequestered within stroma. Anti-CD25 antibody administration along with castration enhanced CTL access to cancerous glands but did not increase effector function. Intraprostatic injection of LIGHT-expressing tumor cells increased the proportion of CD8+ T cells with functional capacity within the cancerous gland. In addition, Treg depletion within the tumor was enhanced. Together, these manipulations significantly reduced castration-resistant tumor burden. Thus, our results indicate that immune modulations, which prevent Treg accumulation and augment effector cell infiltration of prostatic epithelium, may be effective in reducing tumor burden or preventing tumor recurrence after androgen ablation therapy.

Abstract B37: PSCA haploinsufficiency enhances prostate tumor growth in prostate-specific Pten knockout mice

Prostate cancer is a heterogeneous disease, with multiple stages of cancer evident within an individual organ. Although some of the genetic changes necessary to initiate or advance prostate cancer have been identified, in order to develop effective therapies, it is critical to understand the different means by which this disease develops and progresses. Prostate Stem Cell Antigen (PSCA) is a GPI-anchored cell surface protein that is expressed in the normal epithelial cells of a restricted set of organs, including prostate, bladder, stomach, kidney and pancreas. Over-expression of PSCA is found in all stages of prostate cancer, from PIN to metastasis.

We are investigating the biological function of PSCA in prostate tumorigenesis. We recently reported that deletion of PSCA increases metastasis of TRAMP-induced prostate tumors in mice, suggesting that PSCA may function as a tumor suppressor. To determine the effect of modulating PSCA dosage in the context of another oncogenic signal implicated in human prostate cancer development, we crossed PSCA knockout mice to prostate-specific Pten knockout mice, and analyzed the animals at 30 weeks of age. Pten −/−;PSCA +/− mice developed significantly larger prostate tumors than Pten −/− mice that are wild-type for PSCA. These results also suggest that PSCA may function as a tumor suppressor. In contrast, mice with deletion of both copies of the PSCA gene (Pten −/−; PSCA −/− mice) developed tumors similar in size to Pten −/−;PSCA +/+ animals, consistent with the possibility that PSCA function may contribute to the early stages of cancer development.

Together, our results suggest that modulation of PSCA gene dosage affects cancer initiation and progression, indicating a putative dual role for PSCA in epithelial cancer. Our current experiments are designed to determine the molecular mechanism of PSCA function.

Citation Information: Cancer Res 2009;69(23 Suppl):B37.

Noninvasive imaging of cell-mediated therapy for treatment of cancer

Cell-mediated therapy (immunotherapy) for the treatment of cancer is an active area of investigation in animal models and clinical trials. Despite many advances, objective responses to immunotherapy are observed in a small number of cases, for certain tumor types. To better understand differences in outcomes, it is critical to develop assays for tracking effector cell localization and function in situ. The fairly recent use of molecular imaging techniques to track cell populations has presented researchers and clinicians with a powerful diagnostic tool for determining the efficacy of cell-mediated therapy for the treatment of cancer. This review highlights the application of whole-body noninvasive radioisotopic, magnetic, and optical imaging methods for monitoring effector cells in vivo. Issues that affect sensitivity of detection, such as methods of cell marking, efficiency of cell labeling, toxicity, and limits of detection of imaging modalities, are discussed.

Digital spectral separation methods and systems for bioluminescence imaging

We propose a digital spectral separation (DSS) system and methods to extract spectral information optimally from a weak multi-spectral signal such as in the bioluminescent imaging (BLI) studies. This system utilizes our newly invented spatially-translated spectral-image mixer (SSM), which consists of dichroic beam splitters, a mirror, and a DSS algorithm. The DSS approach overcomes the shortcomings of the data acquisition scheme used for the current BLI systems. Primarily, using our DSS scheme, spectral information will not be filtered out. Accordingly, truly parallel multi-spectral multi-view acquisition is enabled for the first time to minimize experimental time and optimize data quality. This approach also permits recovery of the bioluminescent signal time course, which is useful to study the kinetics of multiple bioluminescent probes using multi-spectral bioluminescence tomography (MSBT).

Deletion of PSCA increases metastasis of TRAMP-induced prostate tumors without altering primary tumor formation

BACKGROUND

Prostate stem cell antigen (PSCA) is expressed in normal epithelium of various tissues, in embryos and adult animals. PSCA expression is upregulated in up to 70% of prostate tumors and metastases, and a subset of bladder and pancreatic cancers. However, its function is unknown. We studied the effect of targeted gene deletion of PSCA on normal organ development and prostate carcinogenesis.

METHODS

PSCA +/+, PSCA +/-, and PSCA -/- mice were bred and aged to 22 months. A cohort of animals was treated with gamma-irradiation at 2 and 6 months of age. PSCA knockout mice were crossed to TRAMP mice and TRAMP+ PSCA +/+, TRAMP+ PSCA +/-, and TRAMP+ PSCA -/- mice and offspring aged to 10 months of age. Tissues were analyzed by RT-PCR, histology, and immunohistochemistry for markers of proliferation, apoptosis, angiogenesis, and tumor progression.

RESULTS

PSCA knockout animals were viable, fertile and indistinguishable from wild-type littermates. Spontaneous or radiation-induced primary epithelial tumor formation was also similar in wild-type and PSCA knockout mice. We observed an increased frequency of metastasis in TRAMP+ PSCA heterozygous and knockout mice, compared to TRAMP+ wild-type mice. Metastases were largely negative for PSCA and androgen receptor. Cleaved-caspase 3 and CD31 staining was similar in all genotypes. Aurora-A and Aurora-B kinases were detected in the cytoplasm of PSCA heterozygous and knockout tumors, suggesting aberrant kinase function.

CONCLUSION

These data suggest that PSCA may play a role in limiting tumor progression in certain contexts, and deletion of PSCA may promote tumor migration and metastasis.

Structural changes of DNA induced by mono- and binuclear cancer drugs

The structural features of the drug-DNA adducts resulted from treatment of DNA with the platinum based mononuclear drug cisplatin and the binuclear drug [{trans-PtCl(NH3)2}2H2N(CH2)4NH2]Cl2 or bis(platin) have been investigated by atomic force microscopy (AFM). Reduction in the contour length of the DNA fragments has been observed after cisplatin treatment while, compaction and aggregation are found to be the primary structural modifications following treatment with the binuclear drug. The intermolecular interaction upon bis(platin) treatment leads to observation of highly condense aggregates without a distinct sight of single isolated DNA molecule. These differences in drug binding indicate that unlike the mononuclear drug cisplatin, bis(platin) causes extensive interhelical/intermolecular cross-linking through its multiple linking sites. To our knowledge, this is the first report of a comparative AFM study to monitor the effects of a mono- and a binuclear platinum anti-cancer drug on DNA structure. These observations should provide clues towards explaining the distinct biological activities of the two drugs.