Carboplatin enhances lymphocyte-endothelial interactions to promote CD8+ T cell trafficking into the ovarian tumor microenvironment.

OBJECTIVES: Standard chemotherapy agents, including carboplatin, have known immunogenic properties. We sought to determine how carboplatin may influence lymphocyte trafficking to tumor sites. METHODS: Murine models of ovarian cancer were utilized to examine lymphocyte trafficking with common clinically used agents including carboplatin, anti-PD-1 antibody, or anti-VEGFR-2 antibody. Adhesion interactions of lymphocytes with tumor vasculature were measured using intravital microscopy, lymphocyte homing with immunohistochemistry, and treatment groups followed for overall survival. RESULTS: Carboplatin chemotherapy profoundly alters the tumor microenvironment to promote lymphocyte adhesive interactions with tumor vasculature and resultant improvement in lymphocyte trafficking. The measured results seen with carboplatin in the tumor microenvironment were superior to anti-PD-1 treatment or anti-VEGFR-2 which may have contributed to increased overall survival in carboplatin treated groups. CONCLUSIONS: These novel findings suggest a role for chemotherapeutic agents to broadly influence anti-tumor immune responses beyond the induction of immunogenic tumor cell death.

Whole-exome sequencing of ovarian cancer families uncovers putative predisposition genes.

Despite the identification of several ovarian cancer (OC) predisposition genes, a large proportion of familial OC risk remains unexplained. We adopted a two-stage design to identify new OC predisposition genes. We first carried out a large germline whole-exome sequencing study on 158 patients from 140 families with significant OC history, but without evidence of genetic predisposition due to BRCA1/2. We then evaluated the potential candidate genes in a large case-control association study involving 381 OC cases in the Cancer Genome Atlas project and 27,173 population controls from the Exome Aggregation Consortium. Two new putative OC risk genes were identified, namely, ANKRD11, a putative tumor suppressor, and POLE, an enzyme involved in DNA repair and replication. These two genes likely confer moderate OC risk. We performed in vitro experiments and showed an ANKRD11 mutation identified in our patients markedly lowered the protein expression by compromising protein stability. Upon future validation and functional characterization, these genes may shed light on cancer etiology along with improving ascertainment power and preventive care of individuals at high risk of OC.

Immunotherapy for Gynecologic Cancer: Current Applications and Future Directions.

The role of the immune system in the development of cancer has been a subject of ongoing clinical investigation in recent years. Emerging data demonstrate that tumorigenesis resulting in ovarian, uterine, and cervical cancers is a consequence of impaired host immune responses to cancerous cells. Leveraging the immune system through the use of immune checkpoint inhibitors, therapeutic vaccine therapy, and adoptive cell transfer presents a profound opportunity to revolutionize cancer treatment. This review will encompass the role of the immune system in development of gynecologic cancers and highlight recent data regarding immunotherapy applications in ovarian, uterine, and cervical cancers.

Nature of tumour rejection antigens in ovarian cancer.

Major progress in the analysis of human immune responses to cancer has been made through the molecular characterization of human tumour antigens. The development of therapeutic strategies for eliciting immune-mediated rejection of tumours has accelerated due to the elucidation of the molecular basis for tumour cell recognition and destruction by immune cells. Of the various human tumour antigens defined to date in ovarian cancer, the cancer-testis (CT) family of antigens have been studied extensively preclinically and clinically because of their testis-restricted expression in normal tissues and ability to elicit robust immune responses. Recent developments in cancer sequencing technologies offer a unique opportunity to identify tumour mutations with the highest likelihood of being expressed and recognized by the immune system. Such mutations, or neoantigens, could potentially serve as specific immune targets for T-cell-mediated destruction of cancer cells. This review will highlight current work in selecting tumour rejection antigens in ovarian cancer for improving the efficacy of immunotherapy.

Metabolomic prediction of endometrial cancer.

INTRODUCTION: Endometrial cancer (EC) is associated with metabolic disturbances including obesity, diabetes and metabolic syndrome. Identifying metabolite biomarkers for EC detection has a crucial role in reducing morbidity and mortality. OBJECTIVE: To determine whether metabolomic based biomarkers can detect EC overall and early-stage EC. METHODS: We performed NMR and mass spectrometry based metabolomic analyses of serum in EC cases versus controls. A total of 46 early-stage (FIGO stages I-II) and 10 late-stage (FIGO stages III-IV) EC cases constituted the study group. A total of 60 unaffected control samples were used. Patients and controls were divided randomly into a discovery group (n = 69) and an independent validation group (n = 47). Predictive algorithms based on biomarkers and demographic characteristics were generated using logistic regression analysis. RESULTS: A total of 181 metabolites were evaluated. Extensive changes in metabolite levels were noted in the EC versus the control group. The combination of C14:2, phosphatidylcholine with acyl-alkyl residue sum C38:1 (PCae C38:1) and 3-hydroxybutyric acid had an area under the receiver operating characteristics curve (AUC) (95% CI) = 0.826 (0.706-0.946) and a sensitivity = 82.6%, and specificity = 70.8% for EC overall. For early EC prediction: BMI, C14:2 and PC ae C40:1 had an AUC (95% CI) = 0.819 (0.689-0.95) and a sensitivity = 72.2% and specificity = 79.2% in the validation group. CONCLUSIONS: EC is characterized by significant perturbations in important cellular metabolites. Metabolites accurately detected early-stage EC cases and EC overall which could lead to the development of non-invasive biomarkers for earlier detection of EC and for monitoring disease recurrence.

NY-ESO-1 expression predicts an aggressive phenotype of ovarian cancer.

OBJECTIVES: NY-ESO-1 is a cancer testis antigen and a promising target for immunotherapy. The purpose of this study was to determine the expression frequency, immunogenicity, and clinical impact of NY-ESO-1 in ovarian cancer. METHODS: Immunohistochemistry (IHC), reverse-transcription polymerase chain reaction (RT-PCR), and quantitative-PCR (qRT-PCR) were utilized in an ovarian cancer (including Fallopian tube and primary peritoneal cancers) patient cohort; humoral responses against NY-ESO-1 were determined by ELISA. Clinicopathologic outcomes including progression-free (PFS) and overall (OS) survival were evaluated based on NY-ESO-1 expression. Cohen's kappa (κ) tested agreement between expression tests. RESULTS: NY-ESO-1 expression was detected by any method in 40.7% of 1002 patients' tumors (NY-ESO-1+) and baseline humoral response was identified in 19.0% of 689 tested patients. NY-ESO-1+ patients were older (p<0.001), higher stage (85% stage III/IV vs. 76.4%, p=0.015), less likely to have a complete response to initial therapy (53.9% vs. 68.9%, p=0.002), had more serous histotype (74.5% vs. 66.9%, p=0.011), and had more grade 3 tumors (83.7% vs. 70.8%, p<0.001). There was a trend towards shorter PFS (22.2 vs. 25.0months, p=0.07) and significantly shorter OS (42.9 vs. 50.0months, p=0.003) among NY-ESO-1+ patients. A subset analysis of NY-ESO-1+ patients that received immunotherapy demonstrated improved OS by >2years (52.6 vs. 27.2months, p<0.001). CONCLUSIONS: This study is the first demonstration of an association between NY-ESO-1 expression and an aggressive cancer phenotype. The relatively high expression frequency of NY-ESO-1 in ovarian cancer patients coupled with the poor clinical outcomes in NY-ESO-1+ patients reveals an underappreciated need for targeted therapy against this antigen. In support, our study reveals that NY-ESO-1+ patients enrolled on immunotherapy trials targeting the antigen exhibited an improvement in OS.

Multiplex profiling identifies distinct local and systemic alterations during intraperitoneal chemotherapy for ovarian cancer: An NRG Oncology/Gynecologic Oncology Group Study.

OBJECTIVES: Ovarian cancer leads to abdominal carcinomatosis and late stage (III/IV) diagnosis in 75% of patients. Three randomized phase III trials have demonstrated that intraperitoneal (IP) chemotherapy improves outcomes in epithelial ovarian cancer. While IP treatment is validated by clinical trials, there is a poor understanding of the mechanism(s) leading to the survival advantage other than the increased concentration of cytotoxic drugs within the tumor microenvironment. A better understanding of this process through analysis of dynamic biomarkers should promote novel approaches that may enhance tumor clearance. We propose this pilot study to confirm the feasibility of collecting serial peritoneal samples from implanted catheters in women receiving IP chemotherapy. We believe these specimens may be used for multiplex analysis to reveal unique biomarker fluctuations when compared to peripheral blood. METHODS: From 13 women participating on GOG 252, 30 whole blood, 12 peritoneal fluid (PF), and 20 peritoneal wash (PW) with 30mL saline were obtained. Samples were requested prior to the first three chemotherapy cycles. Samples were assessed for volume, cell populations, protein, RNA, and miRNA content changes. RESULTS: Median volume for PF was 1.6mL and 3.1mL for PW. PW is a dilution of PF capable of capturing measurable biomarkers. Peritoneal aspirates contain a unique profile of biomarkers distinct from blood. miRNA undergo earlier alteration with chemotherapy than genes. Flow cytometry does not adequately capture biomarker fluctuations. CONCLUSIONS: As a proof of principle study, this trial provides evidence that sampling the peritoneal cavity can be adapted for biomarker analysis.

Tryptophan Catabolism and Cancer Immunotherapy Targeting IDO Mediated Immune Suppression.

Over the last decade, tryptophan catabolism has been firmly established as a powerful mechanism of innate and adaptive immune tolerance. The catabolism of tryptophan is a central pathway maintaining homeostasis by preventing autoimmunity or immunopathology that would result from uncontrolled and overreacting immune responses. This is driven by the key and rate-limiting enzymes indoleamine-2,3-dioxygenase 1 (IDO1) and tryptophan-2,3-dioxygenase 2 (TDO), resulting in local depletion of tryptophan, while tryptophan catabolites accumulate, including kynurenine and its derivatives, depending on the presence of downstream enzymes in the kynurenine pathway. These metabolic modifications result in a local microenvironment that is profoundly immunosuppressive, as a result of various mechanisms whose respective role remains incompletely characterized. Drugs targeting this pathway, specifically IDO1, are already in clinical trials with the aim at reverting cancer-induced immunosuppression. Recent studies have demonstrated favorable pharmacokinetics profiles for first-generation (Indoximod NLG8189) and second-generation IDO1 inhibitors (INCB024360 and NLG919). Targeting tryptophan catabolism in combination with additional methods of therapy may improve efficacy of cancer immunotherapy. These methods include, but are not limited to vaccination, adoptive cellular therapy, checkpoint inhibitor blockade, and cyclooxygenase-2 (COX2) inhibition. Over the last decade, there has been a considerable increase in our understanding of the regulation and downstream mediators of tryptophan metabolism. This detailed understanding will expand opportunities to interfere with the pathway therapeutically on multiple levels. The object of this chapter is to highlight current and past key findings that implicate tryptophan catabolism as an important mediator of cancer immunity and discuss the development of multiple therapeutic targets.

Cigarette smoke exposure exacerbates lung inflammation and compromises immunity to bacterial infection.

The detrimental impact of tobacco on human health is clearly recognized, and despite aggressive efforts to prevent smoking, close to one billion individuals worldwide continue to smoke. People with chronic obstructive pulmonary disease are susceptible to recurrent respiratory infections with pathogens, including nontypeable Haemophilus influenzae (NTHI), yet the reasons for this increased susceptibility are poorly understood. Because mortality rapidly increases with multiple exacerbations, development of protective immunity is critical to improving patient survival. Acute NTHI infection has been studied in the context of cigarette smoke exposure, but this is the first study, to our knowledge, to investigate chronic infection and the generation of adaptive immune responses to NTHI after chronic smoke exposure. After chronic NTHI infection, mice that had previously been exposed to cigarette smoke developed increased lung inflammation and compromised adaptive immunity relative to air-exposed controls. Importantly, NTHI-specific T cells from mice exposed to cigarette smoke produced lower levels of IFN-γ and IL-4, and B cells produced reduced levels of Abs against outer-membrane lipoprotein P6, with impaired IgG1, IgG2a, and IgA class switching. However, production of IL-17, which is associated with neutrophilic inflammation, was enhanced. Interestingly, cigarette smoke-exposed mice exhibited a similar defect in the generation of adaptive immunity after immunization with P6. Our study has conclusively demonstrated that cigarette smoke exposure has a profound suppressive effect on the generation of adaptive immune responses to NTHI and suggests the mechanism by which prior cigarette smoke exposure predisposes chronic obstructive pulmonary disease patients to recurrent infections, leading to exacerbations and contributing to mortality.

T-regulatory cells and programmed death 1+ T cells contribute to effector T-cell dysfunction in patients with chronic obstructive pulmonary disease.

RATIONALE: Previous studies from our laboratory have shown that peripheral blood mononuclear cells (PBMCs) from patients with chronic obstructive pulmonary disease (COPD) prone to exacerbations with nontypeable Haemophilus influenzae have impaired responses to lipoprotein P6. We hypothesized that an underlying immunosuppressive network could be responsible for the defective antibacterial immunity observed in these patients. We evaluated T regulatory cells (Tregs), myeloid-derived suppressor cells (MDSC), and exhausted T effector cells (programmed death 1 [PD-1](+)) in patients with COPD, because these cells are known to play a pivotal role in suppressing immune responses. OBJECTIVES: We performed an in-depth characterization of Tregs, T effector cells, and MDSC in COPD and correlated their levels and function with disease severity. METHODS: Treg, effector T cell, and MDSC frequency from patients with COPD and healthy subjects' PBMCs were analyzed by flow cytometry. Treg immunosuppressive capacity was measured by in vitro suppression assay. The frequency of interferon-γ producing T cells and T-cell proliferation were measured after blocking CTLA-4 and PD-1. Plasma proinflammatory and immunosuppressive cytokine levels were measured. MEASUREMENTS AND MAIN RESULTS: Significantly increased levels of Tregs, MDSC, and PD-1(+) exhausted effector T cells were present in patients with COPD compared with healthy subjects. Tregs from patients with COPD suppressed P6-specific T-cell proliferation to a greater extent than Tregs from healthy subjects. Plasma levels of Treg-generated cytokines, IL-10, and transforming growth factor-ß were elevated. Blockade of CTLA-4 resulted in significant augmentation of T-cell IFN-γ production in patients with COPD. CONCLUSIONS: Functionally suppressive Tregs, MDSCs, and exhausted PD-1(+) T cells contribute to effector T-cell dysfunction in COPD.

Anti-inflammatory IgG production requires functional P1 promoter in ß-galactoside α2,6-sialyltransferase 1 (ST6Gal-1) gene.

The anti-inflammatory properties associated with intravenous immunoglobulin therapy require the sialic acid modification of the N-glycan of the Fc domain of IgG. Sialylation of the Fc fragment is mediated by ß-galactoside α2,6-sialyltransferase 1 (ST6Gal-1), acting on the Gal(ß4)GlcNAc terminal structure of the biantennary N-glycans on the Fc domain. However, little is known regarding the in vivo regulation of Fc sialylation and its role in the progression of inflammatory processes. Here, we report that decreased Fc sialylation of circulatory IgG accompanies the acute phase response elicited by turpentine exposure or upon acute exposure to either nontypeable Haemophilus influenzae or ovalbumin. However, Fc sialylation was increased 3-fold from the base line upon transition to chronic inflammation by repeated exposure to challenge. The P1 promoter of the ST6Gal-1 gene is critical for Fc sialylation, but P1 does not drive ST6Gal-1 expression in B cells. The Siat1ΔP1 mouse, with a dysfunctional P1 promoter, was unable to produce sialylated Fc in the systemic circulation, despite the presence of Gal(ß4)GlcNAc termini on the Fc glycans. The major contribution of P1 action is to synthesize ST6Gal-1 enzymes that are deposited into the systemic circulation. The data strongly indicate that this pool of extracellular ST6Gal-1 in the blood impacts the sialylation of IgG Fc and that defective Fc sialylation is likely a major contributing mechanism for the proinflammatory tendencies previously noted in Siat1ΔP1 animals.

Single low-dose un-adjuvanted HBsAg nanoparticle vaccine elicits robust, durable immunity.

Chitosan nanoparticles were evaluated as a vaccine delivery system for hepatitis B surface antigen (HBsAg) in the absence of adjuvant. Nano-encapsulated HBsAg (HBsAg chitosan-NP) was endocytosed more rapidly and efficiently by dendritic cells compared to soluble HBsAg. FRET analysis demonstrated that intact nanoparticles were taken up by DCs. To determine the immunogenicity of adjuvant-free nano-encapsulated HBsAg, mice were immunized with a single dose of non-encapsulated HBsAg, HBsAg chitosan-NP, or HBsAg alum. Mice immunized with adjuvant-free nanoparticle elicited anti-HBs antibodies at significantly higher titers compared to mice immunized with HBsAg alum. Elevated numbers of BAFF-R(+) B cells and CD138+ plasma cells account for the heightened anti-HBs response in nanoparticle immunized mice. Increases in Tfh cells provide a mechanism for the accumulation of anti-HBs secreting cells. Thus, chitosan nanoparticle vaccines represent a promising un-adjuvanted platform to generate robust and durable immunity to HBsAg and other subunit antigens following a single low-dose administration. FROM THE CLINICAL EDITOR: In this study, chitosan nanoparticle vaccines are demonstrated as a promising un-adjuvanted platform to generate robust and durable immunity to HBsAg and other subunit antigens following a single low-dose administration in a murine model. The authors also demonstrated superior antibody response induction compared with non-encapsulated HBs antigen and HBsAg aluminum.

Whole-Genome Sequencing Identifies PPARGC1A as a Putative Modifier of Cancer Risk in BRCA1/2 Mutation Carriers.

While BRCA1 and BRCA2 mutations are known to confer the largest risk of breast cancer and ovarian cancer, the incomplete penetrance of the mutations and the substantial variability in age at cancer onset among carriers suggest additional factors modifying the risk of cancer in BRCA1/2 mutation carriers. To identify genetic modifiers of BRCA1/2, we carried out a whole-genome sequencing study of 66 ovarian cancer patients that were enriched with BRCA carriers, followed by validation using data from the Pan-Cancer Analysis of Whole Genomes Consortium. We found PPARGC1A, a master regulator of mitochondrial biogenesis and function, to be highly mutated in BRCA carriers, and patients with both PPARGC1A and BRCA1/2 mutations were diagnosed with breast or ovarian cancer at significantly younger ages, while the mutation status of each gene alone did not significantly associate with age of onset. Our study suggests PPARGC1A as a possible BRCA modifier gene. Upon further validation, this finding can help improve cancer risk prediction and provide personalized preventive care for BRCA carriers.

Metabolic adaptation of ovarian tumors in patients treated with an IDO1 inhibitor constrains antitumor immune responses.

To uncover underlying mechanisms associated with failure of indoleamine 2,3-dioxygenase 1 (IDO1) blockade in clinical trials, we conducted a pilot, window-of-opportunity clinical study in 17 patients with newly diagnosed advanced high-grade serous ovarian cancer before their standard tumor debulking surgery. Patients were treated with the IDO1 inhibitor epacadostat, and immunologic, transcriptomic, and metabolomic characterization of the tumor microenvironment was undertaken in baseline and posttreatment tumor biopsies. IDO1 inhibition resulted in efficient blockade of the kynurenine pathway of tryptophan degradation and was accompanied by a metabolic adaptation that shunted tryptophan catabolism toward the serotonin pathway. This resulted in elevated nicotinamide adenine dinucleotide (NAD+), which reduced T cell proliferation and function. Because NAD+ metabolites could be ligands for purinergic receptors, we investigated the impact of blocking purinergic receptors in the presence or absence of NAD+ on T cell proliferation and function in our mouse model. We demonstrated that A2a and A2b purinergic receptor antagonists, SCH58261 or PSB1115, respectively, rescued NAD+-mediated suppression of T cell proliferation and function. Combining IDO1 inhibition and A2a/A2b receptor blockade improved survival and boosted the antitumor immune signature in mice with IDO1 overexpressing ovarian cancer. These findings elucidate the downstream adaptive metabolic consequences of IDO1 blockade in ovarian cancers that may undermine antitumor T cell responses in the tumor microenvironment.

Nrf2 regulates chronic lung inflammation and B-cell responses to nontypeable Haemophilus influenzae.

Nrf2 is a leucine zipper transcription factor that protects against oxidant-induced injury. Nontypeable Haemophilus influenzae is responsible for frequent disease exacerbations in patients with chronic obstructive pulmonary disease and is responsible for causing otitis media in young children. We hypothesized that Nrf2 would limit inflammatory responses to nontypeable H. influenzae. The objective of this study was to assess the role of Nrf2 in chronic lung inflammation and regulation of immune responses to nontypeable H. influenzae in mice. Wild-type (C57BL/6) mice and Nrf2(-/-) mice were instilled by oropharyngeal aspiration of 1 × 10(6) colony-forming units of live, nontypeable H. influenzae (NTHI) twice a week for 4 to 16 consecutive weeks to generate a chronic inflammatory milieu within the lungs that models chronic bronchitis. Nrf2(-/-) mice had increased lymphocytic airway inflammation compared with WT mice after NTHI challenge. Although the extent of NTHI-induced peribronchovascular inflammation did not significantly differ between the genotypes, plasma cell infiltration was significantly more abundant in Nrf2(-/-) mice. Most strikingly, Nrf2(-/-) mice generated significantly enhanced and persistent levels of serum antibodies against P6, a key outer membrane protein of NTHI. Lung dendritic cells from Nrf2(-/-) mice challenged with NTHI had increased activation markers compared with dendritic cells from similarly treated WT mice. Nrf2 regulates NTHI-induced airway inflammation characterized by lymphocytic and plasma cell infiltration and the activation of lung dendritic cells and B-cell responses in mice. Nrf2 may be a potential therapeutic target in limiting the bacterial infection-induced airway inflammation that drives exacerbations of chronic obstructive pulmonary disease.

Murine model of chronic respiratory inflammation.

The respiratory mucosa is exposed to the external environment each time we breathe and therefore requires a robust and sophisticated immune defense system. As with other mucosal sites, the respiratory mucosal immune system must balance its response to pathogens while also regulating inflammatory immune cell-mediated tissue damage. In the airways, a failure to tightly control immune responses to a pathogen can result in chronic inflammation and tissue destruction with an overzealous response being deleterious for the host. Chronic obstructive pulmonary disease (COPD) is the fourth most common cause of death in the US and both the prevalence of and mortality rate of this disease is increasing annually. COPD is characterized by intermittent disease exacerbation. The causal contribution of bacterial infections to exacerbations of COPD is now widely accepted, accounting for at least 50% of all exacerbations. Non-typeable Haemophilus influenzae and Moraxella catarrhalis (both gram-negative bacteria) along with Streptococcus pneumoniae (a gram-positive bacterium) are the three most common bacterial pathogens that cause respiratory tract infections in COPD patients. The colonization of bacteria in the lower airways is similar to a low-grade smoldering infection that induces chronic airway inflammation. Chronic low-grade infection can induce a persistent inflammatory response in the airways and parenchyma. Inefficient removal of bacteria from the lower respiratory tract is characteristic of chronic bronchitis. Inflammation is believed to be central to the pathogenesis of exacerbations, but a clear understanding of the inflammatory changes during an exacerbation of COPD has yet to emerge. As bacterial colonization of the lung in COPD patients is a chronic inflammatory condition highlighted by frequent bouts of exacerbation and clearance, we sought to reproduce this chronic pathogen-mediated inflammation in a murine model by repeatedly delivering the intact, whole, live bacteria intra-tracheally to the lungs.

IDO1 Expression in Ovarian Cancer Induces PD-1 in T Cells via Aryl Hydrocarbon Receptor Activation.

The immunoregulatory enzyme, indoleamine 2,3-dioxygenase (IDO1) and the PD-1/PD-L1 axis are potent mechanisms that impede effective anti-tumor immunity in ovarian cancer. However, whether the IDO pathway regulates PD-1 expression in T cells is currently unknown. Here we show that tumoral IDO1 expression led to profound changes in tryptophan, nicotinate/nicotinamide, and purine metabolic pathways in the ovarian tumor microenvironment, and to an increased frequency of PD-1+CD8+ tumor infiltrating T cells. We determined that activation of the aryl hydrocarbon receptor (AHR) by kynurenine induced PD-1 expression, and this effect was significantly abrogated by the AHR antagonist CH223191. Mechanistically, kynurenine alters chromatin accessibility in regulatory regions of T cell inhibitory receptors, allowing AHR to bind to consensus XRE motifs in the promoter region of PD-1. These results enable the design of strategies to target the IDO1 and AHR pathways for enhancing anti-tumor immunity in ovarian cancer.

WHSC1/NSD2 regulates immune infiltration in prostate cancer.

BACKGROUND: Immunotherapy in prostate cancer (PCa) lags behind the progresses obtained in other cancer types partially because of its limited immune infiltration. Tumor-resident immune cells have been detected in the prostate, but the regulatory mechanisms that govern tumor infiltration are still poorly understood. To address this gap, we investigated the role of Wolf-Hirschhorn syndrome candidate 1 (WHSC1), a histone methyltransferase enzyme that targets dimethyl and trimethyl H3K36. WHSC1 is known to promote malignant growth and progression in multiple tumors, but its role in the interface between PCa and immune system is unknown. METHODS: RNA Sequencing (RNASeq) data from patients with PCa from The Cancer Genome Atlas (TCGA) were collected and divided into top/bottom 30% based on the expression of WHSC1 and disease-free survival was calculated. Publicly available chromatin immunoprecipitation (ChIPSeq) data were obtained from Cistrome and integrated with the available RNASeq data. RNASeq, ATACSeq and methylomic were analyzed using R Bioconductor packages comparing C42 cells with or without stable knockdown on WHSC1. Flow cytometry was used to measure Major Histocompatibility complex (MHC) levels, MHC-bound ovalbumin and tumor infiltration. C57B6 and NOD scid gamma (NSG) mice were subcutaneously grafted with TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP) C2 cells and treated with MCTP39 (10 mg/kg); tumor size was monitored over time and curves were compared using permutation analyses. All analyses used a significance threshold of 0.05. RESULTS: Leveraging TCGA data, we demonstrated that elevated WHSC1 levels positively correlate with the presence of an immunosuppressive microenvironment. We validated those results in vitro, demonstrating that genetic and pharmacological inhibition of WHSC1 restores antigen presentation. This occurs via an elegant epigenetic regulation of gene expression at the chromatin and DNA methylation levels. In vivo studies in immunocompetent mice also show an increased frequency of CD8+ T cells in tumors from mice treated with WHSC1 inhibitor, supporting the hypothesis that the antitumor effect following WHSC1 inhibition requires a fully functional immune system. CONCLUSIONS: This study demonstrates a novel role for WHSC1 in defining immune infiltration in PCa, with significant future implications for the use of immunotherapies in prostate malignancies.

Circulating CD14+ HLA-DRlo/- monocytic cells as a biomarker for epithelial ovarian cancer progression.

PROBLEM: Previous studies identified circulating CD14+ HLA-DRlo/- monocytic cells as an immune suppressive subset in solid malignancies, such as prostate, renal cell carcinoma, and pancreatic cancer. Such monocytic cells have been implicated not only in tumour progression but also as a potential barrier for immunotherapy. This study examined the relationship between the frequency of circulating monocytic cells and epithelial ovarian cancer (EOC) progression pre- and post-frontline chemotherapy, defined by disease stage, which is a leading prognostic factor for this malignancy. METHOD OF STUDY: Incident cases of 236 women with EOC were recruited and comprehensive flow cytometry was utilized to assess the frequency of peripheral blood CD33+ CD11b+ HLA-DR-/low CD14+ CD15- monocytic cells, henceforth termed CD14+ HLA-DRlo/- monocytic cells, prior to and after completion of frontline chemotherapy. Multivariable odds ratios (OR) were used to estimate the association between CD14+ HLA-DRlo/- monocytic cell percentages and disease stage. Wilcoxon signed-rank tests evaluated changes in these monocytic cell levels pre- and post-chemotherapy in a patient subset (n = 70). RESULTS: Patients with elevated frequencies of circulating CD14+ HLA-DRlo/- monocytic cells at diagnosis were at 3.33-fold greater odds of having advanced stage (III/IV) EOC (CI: 1.04-10.64), with a significant trend in increasing CD14+ HLA-DRlo/- monocytic cell levels (P = .04). There was a 2.02% median decrease of these monocytic cells post-chemotherapy among a subset of patients with advanced stage disease (P < .0001). CONCLUSION: These findings support the potential clinical relevance of CD14+ HLA-DRlo/- monocytic cells in EOC for prognosis and may indicate a non-invasive biomarker to measure disease progression.

Transgenic plant-based oral vaccines.

Oral vaccines offer significant advantages over needle-based vaccines for achieving universal childhood vaccination goals. The expression of vaccine antigens in transgenic plants has the potential to provide a convenient, safe approach for oral vaccination and thus a feasible alternative to traditional parenteral vaccines. Many developments in the field have ushered in improvements such as enhanced protein antigen expression for the use of plants as factories for vaccine production, and facilitated studies pertaining to immunogenicity of candidate vaccines. Oral delivery of plant-based vaccines offers the benefit of antigen protection within the harsh intestinal environment. Within the gut, mucosal immune cells are poised to respond to pathogens, but can also be exploited to elicit protective immune responses to oral vaccines. Inclusion of mucosal adjuvants during immunization with the vaccine antigen has been an important step towards the success of plant-based vaccines. This review discusses the mechanisms that control mucosal immune responses and highlights some of the studies and the results achieved following immunization with transgenic plants.