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Although ovarian cancer has a low incidence rate, it remains the most deadly gynecologic malignancy. Previous work has demonstrated that the DNMTi 5-Azacytidine (5AZA-C) activates type I interferon signaling to increase IFNγ+ T cells and natural killer (NK) cells and reduce the percentage of macrophages in the tumor microenvironment. To improve the efficacy of epigenetic therapy, we hypothesized that the addition of α-difluoromethylornithine (DFMO), an ornithine decarboxylase inhibitor, may further decrease immunosuppressive cell populations improving outcome. We tested this hypothesis in an immunocompetent mouse model for ovarian cancer and found that in vivo, 5AZA-C and DFMO, either alone or in combination, significantly increased survival, decreased tumor burden, and caused recruitment of activated (IFNγ+) CD4+ T cells, CD8+ T cells, and NK cells. The combination therapy had a striking increase in survival when compared with single-agent treatment, despite a smaller difference in recruited lymphocytes. Instead, combination therapy led to a significant decrease in immunosuppressive cells such as M2 polarized macrophages and an increase in tumor-killing M1 macrophages. In this model, depletion of macrophages with a CSF1R-blocking antibody reduced the efficacy of 5AZA-C + DFMO treatment and resulted in fewer M1 macrophages in the tumor microenvironment. These observations suggest our novel combination therapy modifies macrophage polarization in the tumor microenvironment, recruiting M1 macrophages and prolonging survival.Significance:Combined epigenetic and polyamine-reducing therapy stimulates M1 macrophage polarization in the tumor microenvironment of an ovarian cancer mouse model, resulting in decreased tumor burden and prolonged survival.

Supplementary data including polyamine levels, addition of anti-PD-1 to therapy, and flow cytometry plots.

Although ovarian cancer has a low incidence rate, it remains the most deadly gynecologic malignancy. Previous work has demonstrated that the DNMTi 5-Azacytidine (5AZA-C) activates type I interferon signaling to increase IFNγ+ T cells and natural killer (NK) cells and reduce the percentage of macrophages in the tumor microenvironment. To improve the efficacy of epigenetic therapy, we hypothesized that the addition of α-difluoromethylornithine (DFMO), an ornithine decarboxylase inhibitor, may further decrease immunosuppressive cell populations improving outcome. We tested this hypothesis in an immunocompetent mouse model for ovarian cancer and found that in vivo, 5AZA-C and DFMO, either alone or in combination, significantly increased survival, decreased tumor burden, and caused recruitment of activated (IFNγ+) CD4+ T cells, CD8+ T cells, and NK cells. The combination therapy had a striking increase in survival when compared with single-agent treatment, despite a smaller difference in recruited lymphocytes. Instead, combination therapy led to a significant decrease in immunosuppressive cells such as M2 polarized macrophages and an increase in tumor-killing M1 macrophages. In this model, depletion of macrophages with a CSF1R-blocking antibody reduced the efficacy of 5AZA-C + DFMO treatment and resulted in fewer M1 macrophages in the tumor microenvironment. These observations suggest our novel combination therapy modifies macrophage polarization in the tumor microenvironment, recruiting M1 macrophages and prolonging survival. Significance: Combined epigenetic and polyamine-reducing therapy stimulates M1 macrophage polarization in the tumor microenvironment of an ovarian cancer mouse model, resulting in decreased tumor burden and prolonged survival.

DNA damage is ubiquitous and can arise from endogenous or exogenous sources. DNA-damaging alkylating agents are present in environmental toxicants as well as in cancer chemotherapy drugs and are a constant threat, which can lead to mutations or cell death. All organisms have multiple DNA repair and DNA damage tolerance pathways to resist the potentially negative effects of exposure to alkylating agents. In bacteria, many of the genes in these pathways are regulated as part of the SOS reponse or the adaptive response. In this work, we probed the cellular responses to the alkylating agents chloroacetaldehyde (CAA), which is a metabolite of 1,2-dichloroethane used to produce polyvinyl chloride, and styrene oxide (SO), a major metabolite of styrene used in the production of polystyrene and other polymers. Vinyl chloride and styrene are produced on an industrial scale of billions of kilograms annually and thus have a high potential for environmental exposure. To identify stress response genes in E. coli that are responsible for tolerance to the reactive metabolites CAA and SO, we used libraries of transcriptional reporters and gene deletion strains. In response to both alkylating agents, genes associated with several different stress pathways were upregulated, including protein, membrane, and oxidative stress, as well as DNA damage. E. coli strains lacking genes involved in base excision repair and nucleotide excision repair were sensitive to SO, whereas strains lacking recA and the SOS gene ybfE were sensitive to both alkylating agents tested. This work indicates the varied systems involved in cellular responses to alkylating agents, and highlights the specific DNA repair genes involved in the responses.

Memory B cell reserves can generate protective antibodies against repeated SARS-CoV-2 infections, but with unknown reach from original infection to antigenically drifted variants. We charted memory B cell receptor-encoded antibodies from 19 COVID-19 convalescent subjects against SARS-CoV-2 spike (S) and found seven major antibody competition groups against epitopes recurrently targeted across individuals. Inclusion of published and newly determined structures of antibody-S complexes identified corresponding epitopic regions. Group assignment correlated with cross-CoV-reactivity breadth, neutralization potency, and convergent antibody signatures. Although emerging SARS-CoV-2 variants of concern escaped binding by many members of the groups associated with the most potent neutralizing activity, some antibodies in each of those groups retained affinity—suggesting that otherwise redundant components of a primary immune response are important for durable protection from evolving pathogens. Our results furnish a global atlas of S-specific memory B cell repertoires and illustrate properties driving viral escape and conferring robustness against emerging variants., Graphical abstract, Unbiased charting of memory B cell receptor-encoded antibodies from COVID-19 convalescent subjects identifies seven major antibody competition groups recognizing epitopic regions with group assignment correlating with cross-CoV-reactivity breadth and neutralization potency. SARS-CoV-2 variants tend to escape antibodies from groups with the most potent neutralizers, but many retain affinity, showing that redundant components of a primary immune response establish durable protection from evolving pathogens.

Profiling coronaviruses Among the coronaviruses that infect humans, four cause mild common colds, whereas three others, including the currently circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), result in severe infections. Shrock et al. used a technology known as VirScan to probe the antibody repertoires of hundreds of coronavirus disease 2019 (COVID-19) patients and pre–COVID-19 era controls. They identified hundreds of antibody targets, including several antibody epitopes shared by the mild and severe coronaviruses and many specific to SARS-CoV-2. A machine-learning model accurately classified patients infected with SARS-CoV-2 and guided the design of an assay for rapid SARS-CoV-2 antibody detection. The study also looked at how the antibody response and viral exposure history differ in patients with diverging outcomes, which could inform the production of improved vaccine and antibody therapies. Science , this issue p. eabd4250

The global coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made the development of a vaccine a top biomedical priority. In this study, we developed a series of DNA vaccine candidates expressing different forms of the SARS-CoV-2 spike (S) protein and evaluated them in 35 rhesus macaques. Vaccinated animals developed humoral and cellular immune responses, including neutralizing antibody titers at levels comparable to those found in convalescent humans and macaques infected with SARS-CoV-2. After vaccination, all animals were challenged with SARS-CoV-2, and the vaccine encoding the full-length S protein resulted in >3.1 and >3.7 log10 reductions in median viral loads in bronchoalveolar lavage and nasal mucosa, respectively, as compared with viral loads in sham controls. Vaccine-elicited neutralizing antibody titers correlated with protective efficacy, suggesting an immune correlate of protection. These data demonstrate vaccine protection against SARS-CoV-2 in nonhuman primates.

Antibodies are key immune effectors that confer protection against pathogenic threats. The nature and longevity of the antibody response to SARS-CoV-2 infection is not well defined. We charted longitudinal antibody responses to SARS-CoV-2 in 92 subjects after symptomatic COVID-19. Antibody responses to SARS-CoV-2 are unimodally distributed over a broad range, with symptom severity correlating directly with virus-specific antibody magnitude. Seventy-six subjects followed longitudinally to ∼100 days demonstrated marked heterogeneity in antibody duration dynamics. Virus-specific IgG decayed substantially in most individuals, whereas a distinct subset had stable or increasing antibody levels in the same timeframe despite similar initial antibody magnitudes. These individuals with increasing responses recovered rapidly from symptomatic COVID-19 disease, harbored increased somatic mutations in virus-specific memory B cell antibody genes, and had persistent higher frequencies of previously activated CD4+ T cells. These findings illuminate an efficient immune phenotype that connects rapid symptom clearance to differential antibody durability dynamics., Highlights SARS-CoV-2 antibody responses range from negligible to robust in mild COVID-19 Some individuals maintain stable or increased SARS-CoV-2 IgG, while most decline Those who sustain virus-specific IgG production tend to have shorter disease courses Virus-specific B cells from “sustainers” have more SHM early after disease resolution, Longitudinal analyses of antibody responses to SARS-CoV-2 demonstrate that individuals with sustained virus-specific IgG production have shorter disease trajectories, with a subset demonstrating increased somatic hypermutation and higher levels of activated CD4+ cells.

In the letter by Haffner et al. (1), they report that seminoma cell-intrinsic DNA hypomethylation is associated with endogenous retroviral expression, an IFN response, and lymphocytic infiltration. Their data complement and support our recent therapeutic study in a mouse model of ovarian cancer (2) and support our observations that low doses of the DNA methyltransferase (DNMT) inhibitor azacytidine (AZA), in combination with the histone deacetylase inhibitor, givinostat, activate type 1 IFN signaling in ovarian (2) and lung (3) cancer cells to increase numbers and activation of immune cells in the tumor microenvironment and to increase sensitivity to the … [↵][1]5To whom correspondence may be addressed. Email: zahnoci{at}jhmi.edu or sbaylin{at}jhmi.edu. [1]: #xref-corresp-1-1

Ovarian cancer is the most lethal of all gynecological cancers, and there is an urgent unmet need to develop new therapies. Epithelial ovarian cancer (EOC) is characterized by an immune suppressive microenvironment, and response of ovarian cancers to immune therapies has thus far been disappointing. We now find, in a mouse model of EOC, that clinically relevant doses of DNA methyltransferase and histone deacetylase inhibitors (DNMTi and HDACi, respectively) reduce the immune suppressive microenvironment through type I IFN signaling and improve response to immune checkpoint therapy. These data indicate that the type I IFN response is required for effective in vivo antitumorigenic actions of the DNMTi 5-azacytidine (AZA). Through type I IFN signaling, AZA increases the numbers of CD45+ immune cells and the percentage of active CD8+ T and natural killer (NK) cells in the tumor microenvironment, while reducing tumor burden and extending survival. AZA also increases viral defense gene expression in both tumor and immune cells, and reduces the percentage of macrophages and myeloid-derived suppressor cells in the tumor microenvironment. The addition of an HDACi to AZA enhances the modulation of the immune microenvironment, specifically increasing T and NK cell activation and reducing macrophages over AZA treatment alone, while further increasing the survival of the mice. Finally, a triple combination of DNMTi/HDACi plus the immune checkpoint inhibitor α-PD-1 provides the best antitumor effect and longest overall survival, and may be an attractive candidate for future clinical trials in ovarian cancer.

Although ovarian cancer has a low incidence rate encompassing roughly 1% of all new cancers, it remains the most deadly gynecologic malignancy. Our lab has designed a novel combination therapy which combines a DNA methyl transferase inhibitor (DNMTi) and ornithine decarboxylase inhibitor that together, alter the tumor microenvironment to inhibit ovarian tumor growth. Previous work has demonstrated that the DNMTi 5-Azacytidine (AZA) activates type I interferon signaling (Li, 2014, Chiappinelli, 2015) to increase IFNγ+ T cells and NK cells and reduce the percentage of macrophages and myeloid derived suppressor cells (MDSCs) in the tumor microenvironment (Stone, 2017). To improve the efficacy of epigenetic therapy, we hypothesized that the addition of α-difluoromethylornithine (DFMO), an ornithine decarboxylase inhibitor may decrease activity of MDSCs through inhibition of arginase. Immunocompetent C57Bl/6 mice were injected with syngeneic mouse ovarian surface epithelial (MOSE) tumor cells (ID8-VEGF-Defensin) and subsequently treated with AZA, DFMO, or combination AZA+DFMO. After several weeks, mice developed hemorrhagic ascites that was drained, processed and stained for cell-surface markers and analyzed by flow cytometry to identify T cells, NK cells, and macrophages. We found that in vivo AZA, DFMO, and AZA+DFMO significantly increased survival in mice, decreased tumor burden, and caused recruitment of activated (IFNγ+) CD4+ T cells, CD8+ T cells, and NK Cells compared to vehicle. The combination therapy had a striking increase in survival when compared to single agent treatment; however, the difference in recruited lymphocytes was less striking. Instead, combination therapy led to the most dramatic decrease in immunosuppressive cells such as M2 polarized macrophages and increase in tumor-killing M1 macrophages. Using a CSF1R blocking antibody, we found that depleting macrophages in this model reduced the efficacy of AZA+DFMO treatment, and resulted in fewer M1 macrophages in the tumor microenvironment. We thus conclude that our novel combination therapy modifies macrophage polarization in the tumor microenvironment, recruiting M1 macrophages and prolonging survival. We hypothesize that this treatment regimen could have a widespread impact on macrophage-rich tumors in general, and plan to test this hypothesis in additional tumor models. Citation Format: Meghan Travers, Stephen Brown, Matthew Dunworth, Cassandra Holbert, Robert Casero, Cynthia Zahnow. DFMO and 5-azacytidine increase M1 macrophages in the tumor microenvironment of an ovarian cancer mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2805.

Malignant ascites in ovarian cancer develops in the setting of recurrent and advanced metastatic disease and is associated with poor prognosis. Emerging evidence has demonstrated that ovarian cancer patients have altered metabolism and an immunosuppressive environment in the ascites fluid. Inasmuch as the rapid proliferation of ovarian cancer cells and development of ascites is dependent on glutamine metabolism, we hypothesized that targeting the glutamine metabolism can inhibit the development of ascites and enhance anti-tumor immunity in ovarian cancer. To test this hypothesis, we developed a novel small molecule glutamine antagonist (prodrug of 6-Diazo-5-oxo-l-norleucine, JHU-083). By employing JHU-083, we evaluated this hypothesis in mice bearing an aggressive and metastatic ovarian cancer (ID8 cell line with an overexpression of Defb29 and Vegfa). Targeting glutamine metabolism led to markedly reduced progression of ascites along with reduced tumor cell numbers. Furthermore, JHU-083 treatment also led to a marked diminution of the volume of fluid in mice with already established ascites. Inhibition of glutamine metabolism also led to a less suppressive tumor microenvironment by blocking the recruitment of myeloid derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) to the ascites fluid. Functionally, both the TAMs and tumor cells from the JHU-083 treated group showed a lower expression of PDL1 compared to the vehicle treated group. Additionally, we also observed reduced regulatory T cell (T regs) percentages and numbers with JHU-083 treatment. These findings are consistent with our previous observations that targeting glutamine metabolism can inhibit the generation and recruitment of MDSC and T regs by targeting both tumor cell and immune cell metabolism. Further, LC-MS based metabolite analysis of the ovarian cancer ascites fluid from JHU-083 treated mice revealed distinct differences in urea-ornithine pathway, nucleotide synthesis, and redox balance related metabolites. In light of these findings, ongoing experiments are examining the efficacy of JHU-083 in combination with epigenetic drugs, VEGF inhibitors, PARP inhibitors, and checkpoint blockade. These studies suggest that targeting glutamine metabolism may represent a novel approach to treating metastatic ovarian cancer and ascites. Citation Format: Min-Hee Oh, Meghan Travers, Stephen Brown, Liang Zhao, Im-Meng Sun, Im-Hong Sun, Matthew Arwood, Wei Xu, Samuel Collins, Robert Leone, Eva Prchalova, Rana Rais, Barbara Slusher, Maureen Horton, Cynthia Zahnow, Jonathan Powell. Targeting glutamine metabolism as a mean of treating a murine model of ovarian cancer and ascites development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-022.