Disparities in the use of screening breast magnetic resonance imaging persist in Louisiana after the Affordable Care Act: A question of access, policy, institutional support, or something else?

BACKGROUND: Louisiana continues to have one of the highest breast cancer mortality rates in the nation, and Black women are disproportionally affected. Louisiana has made advances in improving access to breast cancer screening through the expansion of Medicaid. There remains, however, broad underuse of advanced imaging technology such as screening breast magnetic resonance imaging (MRI), particularly for Black women. METHODS: Breast MRI has been proven to be very sensitive for the early detection of breast cancer in women at high risk. MRI is more sensitive than mammography for aggressive, invasive breast cancer types, which disproportionally affect Black women. Here the authors identify potential barriers to breast MRI screening in Black women, propose strategies to address disparities in access, and advocate for specific recommendations for change. RESULTS: Cost was identified as one of the greatest barriers to screening breast MRI. The authors propose implementation of cost-saving, abbreviated protocols to address cost along with lobbying for further expansion of the Affordable Care Act (ACA) to include coverage for screening breast MRI. In addition, addressing gaps in communication and knowledge and facilitating providers' ability to readily identify women who might benefit from MRI could be particularly impactful for high-risk Black women in Louisiana communities. CONCLUSIONS: Since the adoption of the ACA in Louisiana, Black women have continued to have disproportionally high breast cancer mortality rates. This persistent disparity provides evidence that additional change is needed. This change should include exploring innovative ways to make advanced imaging technology such as breast MRI more accessible and expanding research to specifically address community and culturally specific barriers.

The stress-response sensor chop regulates the function and accumulation of myeloid-derived suppressor cells in tumors.

Adaptation of malignant cells to the hostile milieu present in tumors is an important determinant of their survival and growth. However, the interaction between tumor-linked stress and antitumor immunity remains poorly characterized. Here, we show the critical role of the cellular stress sensor C/EBP-homologous protein (Chop) in the accumulation and immune inhibitory activity of tumor-infiltrating myeloid-derived suppressor cells (MDSCs). MDSCs lacking Chop had decreased immune-regulatory functions and showed the ability to prime T cell function and induce antitumor responses. Chop expression in MDSCs was induced by tumor-linked reactive oxygen and nitrogen species and regulated by the activating-transcription factor-4. Chop-deficient MDSCs displayed reduced signaling through CCAAT/enhancer-binding protein-ß, leading to a decreased production of interleukin-6 (IL-6) and low expression of phospho-STAT3. IL-6 overexpression restored immune-suppressive activity of Chop-deficient MDSCs. These findings suggest the role of Chop in tumor-induced tolerance and the therapeutic potential of targeting Chop in MDSCs for cancer immunotherapy.

Myeloid-derived suppressor cells (MDSC): When good intentions go awry.

MDSC are a heterogeneous population of immature myeloid cells that are released by biological stress such as tissue damage and inflammation. Conventionally, MDSC are known for their detrimental role in chronic inflammation and neoplastic conditions. However, their intrinsic functions in immunoregulation, wound healing, and angiogenesis are intended to protect from over-reactive immune responses, maintenance of immunotolerance, tissue repair, and homeostasis. Paradoxically, under certain conditions, MDSC can impair protective immune responses and exacerbate the disease. The transition from protective to harmful MDSC is most likely driven by environmental and epigenetic mechanisms induced by prolonged exposure to unresolved inflammatory triggers. Here, we review several examples of the dual impact of MDSC in conditions such as maternal-fetal tolerance, self-antigens immunotolerance, obesity-associated cancer, sepsis and trauma. Moreover, we also highlighted the evidence indicating that MDSC have a role in COVID-19 pathophysiology. Finally, we have summarized the evidence indicating epigenetic mechanisms associated with MDSC function.

A novel patient-derived xenograft model for claudin-low triple-negative breast cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) subtypes are clinically aggressive and cannot be treated with targeted therapeutics commonly used in other breast cancer subtypes. The claudin-low (CL) molecular subtype of TNBC has high rates of metastases, chemoresistance and recurrence. There exists an urgent need to identify novel therapeutic targets in TNBC; however, existing models utilized in target discovery research are limited. Patient-derived xenograft (PDX) models have emerged as superior models for target discovery experiments because they recapitulate features of patient tumors that are limited by cell-line derived xenograft methods. METHODS: We utilize immunohistochemistry, qRT-PCR and Western Blot to visualize tumor architecture, cellular composition, genomic and protein expressions of a new CL-TNBC PDX model (TU-BcX-2O0). We utilize tissue decellularization techniques to examine extracellular matrix composition of TU-BcX-2O0. RESULTS: Our laboratory successfully established a TNBC PDX tumor, TU-BCX-2O0, which represents a CL-TNBC subtype and maintains this phenotype throughout subsequent passaging. We dissected TU-BCx-2O0 to examine aspects of this complex tumor that can be targeted by developing therapeutics, including the whole and intact breast tumor, specific cell populations within the tumor, and the extracellular matrix. CONCLUSIONS: Here, we characterize a claudin-low TNBC patient-derived xenograft model that can be utilized for therapeutic research studies.

Minocycline blocks asthma-associated inflammation in part by interfering with the T cell receptor-nuclear factor κB-GATA-3-IL-4 axis without a prominent effect on poly(ADP-ribose) polymerase.

Minocycline protects against asthma independently of its antibiotic function and was recently reported as a potent poly(ADP-ribose) polymerase (PARP) inhibitor. In an animal model of asthma, a single administration of minocycline conferred excellent protection against ovalbumin-induced airway eosinophilia, mucus hypersecretion, and Th2 cytokine production (IL-4/IL-5/IL-12(p70)/IL-13/GM-CSF) and a partial protection against airway hyperresponsiveness. These effects correlated with pronounced reduction in lung and sera allergen-specific IgE. A reduction in poly(ADP-ribose) immunoreactivity in the lungs of minocycline-treated/ovalbumin-challenged mice correlated with decreased oxidative DNA damage. The effect of minocycline on PARP may be indirect, as the drug failed to efficiently block direct PARP activation in lungs of N-methyl-N'-nitro-N-nitroso-guanidine-treated mice or H(2)O(2)-treated cells. Minocycline blocked allergen-specific IgE production in B cells potentially by modulating T cell receptor (TCR)-linked IL-4 production at the mRNA level but not through a modulation of the IL-4-JAK-STAT-6 axis, IL-2 production, or NFAT1 activation. Restoration of IL-4, ex vivo, rescued IgE production by minocycline-treated/ovalbumin-stimulated B cells. IL-4 blockade correlated with a preferential inhibition of the NF-κB activation arm of TCR but not GSK3, Src, p38 MAPK, or ERK1/2. Interestingly, the drug promoted a slightly higher Src and ERK1/2 phosphorylation. Inhibition of NF-κB was linked to a complete blockade of TCR-stimulated GATA-3 expression, a pivotal transcription factor for IL-4 expression. Minocycline also reduced TNF-α-mediated NF-κB activation and expression of dependent genes. These results show a potentially broad effect of minocycline but that it may block IgE production in part by modulating TCR function, particularly by inhibiting the signaling pathway, leading to NF-κB activation, GATA-3 expression, and subsequent IL-4 production.

Subpopulations of myeloid-derived suppressor cells impair T cell responses through independent nitric oxide-related pathways.

The accumulation of myeloid-derived suppressor cells (MDSC) in tumor-bearing hosts is a hallmark of malignancy-associated inflammation and a major mediator for the induction of T cell suppression in cancer. MDSC can be divided phenotypically into granulocytic (G-MDSC) and monocytic (Mo-MDSC) subgroups. Several mechanisms mediate the induction of T cell anergy by MDSC; however, the specific role of these pathways in the inhibitory activity of MDSC subpopulations remains unclear. Therefore, we aimed to determine the effector mechanisms by which subsets of tumor-infiltrating MDSC block T cell function. We found that G-MDSC had a higher ability to impair proliferation and expression of effector molecules in activated T cells, as compared to Mo-MDSC. Interestingly, both MDSC subgroups inhibited T cells through nitric oxide (NO)-related pathways, but expressed different effector inhibitory mechanisms. Specifically, G-MDSC impaired T cells through the production of peroxynitrites (PNT), while Mo-MDSC suppressed by the release of NO. The production of PNT in G-MDSC depended on the expression of gp91(phox) and endothelial NO synthase (eNOS), while inducible NO synthase (iNOS) mediated the generation of NO in Mo-MDSC. Deletion of eNOS and gp91(phox) or scavenging of PNT blocked the suppressive function of G-MDSC and induced anti-tumoral effects, without altering Mo-MDSC inhibitory activity. Furthermore, NO-scavenging or iNOS knockdown prevented Mo-MDSC function, but did not affect PNT production or suppression by G-MDSC. These results suggest that MDSC subpopulations utilize independent effector mechanisms to regulate T cell function. Inhibition of these pathways is expected to specifically block MDSC subsets and overcome immune suppression in cancer.

Arginase I levels are decreased in the plasma of pediatric patients with atopic dermatitis.

BACKGROUND: Serum arginase levels have been shown to be elevated in conditions, such as trauma, cancer, chronic wounds, pregnancy, and diabetes. This also has been found to be true in atopic diseases, such as asthma and allergic rhinitis. OBJECTIVE: To study arginase activity in patients with atopic dermatitis (AD). METHODS: In this pilot study, arginase activity levels in 15 pediatric patients with AD were compared with those in controls to determine whether arginase levels in AD are altered as in patients with other atopic diseases. RESULTS: In contrast to the other diseases studied, arginase activity was found to be decreased in granulocytes and in the plasma of patients with AD compared with controls. This finding was coupled with a trend toward higher L-arginine plasma levels. CONCLUSION: In AD, a different mechanism of arginine metabolism seems to be stimulated, leading to the formation of nitric oxide pathway components causing suppression of the arginase pathway and impairment in skin hydration, collagen synthesis, and wound healing.

Regulation of SPDEF expression by DNA methylation in advanced prostate cancer.

Introduction: Prostate cancer (PCa) presents a significant health challenge in men, with a substantial number of deaths attributed to metastatic castration resistant PCa (mCRPC). Moreover, African American men experience disproportionately high mortality rates due to PCa. This study delves into the pivotal role of SPDEF, a prostate specific Ets transcription factor, and its regulation by DNA methylation in the context of PCa progression. Methods: We performed Epigenetic reprogramming using daily treatment with non-toxic dose of 5Aza-2-deoxycytidine (5Aza-dC) for two weeks to assess its impact on PDEF expression in prostate cancer cells. Next, we conducted functional studies on reprogrammed cells, including cell migration (wound-healing assay), invasion (Boyden-Chamber test), and proliferation (MTT assay) to comprehensively evaluate the consequences of altered PDEF expression. We used bisulfite sequencing (BSP) to examine DNA methylation at SPDEF promoter. Simultaneously, we utilized siRNA-mediated targeting of key DNMTs (DNMT1, DNMT3A, and DNMT3B) to elucidate their specific role in regulating PDEF. We measured mRNA and protein expressions using qRT-PCR and immune-blotting techniques, respectively. Results: In this report, we observed that: a) there is a gradual decrease in SPDEF expression with a concomitant increase in methylated CpG sites within the SPDEF gene during prostate cancer progression from lower to higher Gleason grade; b) Expression of DNMT's (DNMT1, 3a and 3b) is increased during prostate cancer progression, and there is an inverse correlation between SPDEF and DNMT expression; c) SPDEF levels are decreased in RC77/T, a line of PCa cells from African American origin similar to PC3 and DU145 cells (CRPC cells), as compared to LNCaP cells , a line of androgen dependent cells,; d) the 5' CpG island of SPDEF gene are hypermethylated in SPDEF-negative CRPC ( PC3, DU145 and RC77/T) cell lines but the same regions are hypomethylated in SPDEF-positive castrate sensitive (LNCaP) cell line ; (e) expression of SPDEF in PCa cells lacking SPDEF decreases cell migration and invasion, but has no significant effect on cell proliferation, and; (f) treatment with the demethylating agent, 5-aza-2'-deoxycytidine, or silencing of the DNMT's by siRNA, partially restores SPDEF expression in SPDEF-negative PCa cell lines, and decreases cell migration and invasion. Discussion: These results indicate hypermethylation is a prevalent mechanism for decreasing SPDEF expression during prostate cancer progression. The data demonstrate that loss of SPDEF expression in prostate cancer cells, a critical step in cellular plasticity, results from a potentially reversible process of aberrant DNA methylation. These studies suggest DMNT activity as a potential therapeutic vulnerability that can be exploited for limiting cellular plasticity, tumor progression, and therapy resistance in prostate cancer.

Bone marrow myeloid-derived suppressor cells (MDSCs) inhibit graft-versus-host disease (GVHD) via an arginase-1-dependent mechanism that is up-regulated by interleukin-13.

Myeloid-derived suppressor cells (MDSCs) are a well-defined population of cells that accumulate in the tissue of tumor-bearing animals and are known to inhibit immune responses. Within 4 days, bone marrow cells cultured in granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor resulted in the generation of CD11b(+)Ly6G(lo)Ly6C(+) MDSCs, the majority of which are interleukin-4Rα (IL-4Rα(+)) and F4/80(+). Such MDSCs potently inhibited in vitro allogeneic T-cell responses. Suppression was dependent on L-arginine depletion by arginase-1 activity. Exogenous IL-13 produced an MDSC subset (MDSC-IL-13) that was more potently suppressive and resulted in arginase-1 up-regulation. Suppression was reversed with an arginase inhibitor or on the addition of excess L-arginine to the culture. Although both MDSCs and MDSC-IL-13 inhibited graft-versus-host disease (GVHD) lethality, MDSC-IL-13 were more effective. MDSC-IL-13 migrated to sites of allopriming. GVHD inhibition was associated with limited donor T-cell proliferation, activation, and proinflammatory cytokine production. GVHD inhibition was reduced when arginase-1-deficient MDSC-IL-13 were used. MDSC-IL-13 did not reduce the graft-versus-leukemia effect of donor T cells. In vivo administration of a pegylated form of human arginase-1 (PEG-arg1) resulted in L-arginine depletion and significant GVHD reduction. MDSC-IL-13 and pegylated form of human arginase-1 represent novel strategies to prevent GVHD that can be clinically translated.

Metabolism of L-arginine by myeloid-derived suppressor cells in cancer: mechanisms of T cell suppression and therapeutic perspectives.

Patients with cancer have an impaired T cell response that can decrease the potential therapeutic benefit of cancer vaccines and other forms of immunotherapy. The establishment of a chronic inflammatory environment in patients with cancer plays a critical role in the induction of T cell dysfunction. The accumulation of myeloid-derived suppressor cells (MDSC) in tumor bearing hosts is a hallmark of malignancy-associated inflammation and a major mediator of the induction of T cell suppression in cancer. Recent findings in tumor bearing mice and cancer patients indicate that the increased metabolism of L-Arginine (L-Arg) by MDSC producing Arginase I inhibits T cell lymphocyte responses. Here, we discuss some of the most recent concepts of how MDSC expressing Arginase I may regulate T cell function in cancer and suggest possible therapeutic interventions to overcome this inhibitory effect.

L-arginine deprivation regulates cyclin D3 mRNA stability in human T cells by controlling HuR expression.

Myeloid-derived suppressor cells are a major mechanism of tumor-induced immune suppression in cancer. Arginase I-producing myeloid-derived suppressor cells deplete l-arginine (L-Arg) from the microenvironment, which arrests T cells in the G(0)-G(1) phase of the cell cycle. This cell cycle arrest correlated with an inability to increase cyclin D3 expression resulting from a decreased mRNA stability and an impaired translation. We sought to determine the mechanisms leading to a decreased cyclin D3 mRNA stability in activated T cells cultured in medium deprived of L-Arg. Results show that cyclin D3 mRNA instability induced by L-Arg deprivation is dependent on response elements found in its 3'-untranslated region (UTR). RNA-binding protein HuR was found to be increased in T cells cultured in medium with L-Arg and bound to the 3'-untranslated region of cyclin D3 mRNA in vitro and endogenously in activated T cells. Silencing of HuR expression significantly impaired cyclin D3 mRNA stability. L-Arg deprivation inhibited the expression of HuR through a global arrest in de novo protein synthesis, but it did not affect its mRNA expression. This alteration is dependent on the expression of the amino acid starvation sensor general control nonderepressible 2 kinase. These data contribute to an understanding of a central mechanism by which diseases characterized by increased arginase I production may cause T cell dysfunction.

Requirement for inducible nitric oxide synthase in chronic allergen exposure-induced pulmonary fibrosis but not inflammation.

The role of inducible NO synthase (iNOS) in allergic airway inflammation remains elusive. We tested the hypothesis that iNOS plays different roles during acute versus chronic airway inflammation. Acute and chronic mouse models of OVA-induced airway inflammation were used to conduct the study. We showed that iNOS deletion was associated with a reduction in eosinophilia, mucus hypersecretion, and IL-5 and IL-13 production upon the acute protocol. Such protection was completely abolished upon the chronic protocol. Interestingly, pulmonary fibrosis observed in wild-type mice under the chronic protocol was completely absent in iNOS(-/-) mice despite persistent IL-5 and IL-13 production, suggesting that these cytokines were insufficient for pulmonary fibrosis. Such protection was associated with reduced collagen synthesis and indirect but severe TGF-beta modulation as confirmed using primary lung smooth muscle cells. Although activation of matrix metalloproteinase-2/-9 exhibited little change, the large tissue inhibitor of metalloproteinase-2 (TIMP-2) increase detected in wild-type mice was absent in the iNOS(-/-) counterparts. The regulatory effect of iNOS on TIMP-2 may be mediated by peroxynitrite, as the latter reversed TIMP-2 expression in iNOS(-/-) lung smooth muscle cells and fibroblasts, suggesting that the iNOS-TIMP-2 link may explain the protective effect of iNOS-knockout against pulmonary fibrosis. Analysis of lung sections from chronically OVA-exposed iNOS(-/-) mice revealed evidence of residual but significant protein nitration, prevalent oxidative DNA damage, and poly(ADP-ribose) polymerase-1 activation. Such tissue damage, inflammatory cell recruitment, and mucus hypersecretion may be associated with substantial arginase expression and activity. The results in this study exemplify the complexity of the role of iNOS in asthma and the preservation of its potential as a therapeutic a target.

Arginine regulation by myeloid derived suppressor cells and tolerance in cancer: mechanisms and therapeutic perspectives.

Patients with cancer have an impaired T-cell response that can decrease the potential therapeutic benefit of cancer vaccines and other forms of immunotherapy. L-arginine (L-Arg) is a conditionally essential amino acid that is fundamental for the function of T lymphocytes. Recent findings in tumor-bearing mice and cancer patients indicate that increased metabolism of L-Arg by myeloid derived suppressor cells (MDSCs) producing arginase I inhibits T-lymphocyte responses. Here we discuss some of the most recent concepts how MDSC expressing arginase I may regulate T-cell function in cancer and other chronic inflammatory diseases and suggest possible therapeutic interventions to overcome this inhibitory effect.

Association of Abdominal Visceral Adiposity and Total Fat Mass with Cancer Incidence and Mortality in White and Black Adults.

BACKGROUND: Race modifies the association between anthropometric measures of obesity and cancer risk. However, the degree to which abdominal visceral adipose tissue (VAT) and total fat mass (FM) are associated with cancer risk is not known. METHODS: The sample included 3,017 White and 1,347 Black adults who were assessed between 1995 and 2016 and followed for outcome assessment through 2017. Abdominal VAT and FM were measured using imaging techniques. The co-primary endpoints were diagnosis of histologically confirmed invasive cancer (excluding nonmelanoma skin cancer) or death from cancer. Multivariable Cox proportional hazards models quantified the HR of incident cancer and cancer mortality. RESULTS: There were 353 incident cancer cases and 75 cancer deaths in an average of 12.9 years of follow-up. Both VAT [HR, 1.21; 95% confidence interval (CI), 1.09-1.36] and FM (HR, 1.25; 95% CI, 1.10-1.43) were significantly associated with incident cancer, while VAT (HR, 1.28; 95% CI, 1.01-1.61) was significantly associated with cancer mortality after adjustment for several covariates. VAT remained significantly associated with cancer incidence (HR, 1.22; 95% CI, 1.03-1.46) after additional inclusion of FM in the multivariable model, but not vice versa. There were no significant sex- or race-interactions. CONCLUSIONS: VAT was associated with risk of cancer and cancer mortality in this cohort, and the associations did not differ by sex or race. The association between VAT and incident cancer was largely independent of total FM. IMPACT: Our results suggest that utility of anthropometry in assessing obesity-related cancer risk may need to be further refined by including more direct measures of adiposity.

Association of Obesity and Diabetes With the Incidence of Breast Cancer in Louisiana.

INTRODUCTION: Breast cancer is a heterogeneous disease, consisting of multiple molecular subtypes. Obesity has been associated with an increased risk for postmenopausal breast cancer, but few studies have examined breast cancer subtypes separately. Obesity is often complicated by type 2 diabetes, but the possible association of diabetes with specific breast cancer subtypes remains poorly understood. METHODS: In this retrospective case-control study, Louisiana Tumor Registry records of primary invasive breast cancer diagnosed in 2010-2015 were linked to electronic health records in the Louisiana Public Health Institute's Research Action for Health Network. Controls were selected from Research Action for Health Network and matched to cases by age and race. Conditional logistic regression was used to identify metabolic risk factors. Data analysis was conducted in 2020‒2021. RESULTS: There was a significant association between diabetes and breast cancer for Luminal A, Triple-Negative Breast Cancer, and human epidermal growth factor 2‒positive subtypes. In multiple logistic regression, including both obesity status and diabetes as independent risk factors, Luminal A breast cancer was also associated with overweight status. Diabetes was associated with increased risk for Luminal A and Triple-Negative Breast Cancer in subgroup analyses, including women aged ≥50 years, Black women, and White women. CONCLUSIONS: Although research has identified obesity and diabetes as risk factors for breast cancer, these results underscore that comorbid risk is complex and may differ by molecular subtype. There was a significant association between diabetes and the incidence of Luminal A, Triple-Negative Breast Cancer, and human epidermal growth factor 2‒positive breast cancer in Louisiana.

Impact of Federal, State, and Local Housing Policies on Disparities in Cardiovascular Disease in Black/African American Men and Women: From Policy to Pathways to Biology.

Racist and discriminatory federal, state, and local housing policies significantly contribute to disparities in cardiovascular disease incidence and mortality for individuals that self-identify as Black or African American. Here we highlight three key housing policies - "redlining," zoning, and the construction of highways - which have wrought a powerful, sustained, and destructive impact on cardiovascular health in Black/African American communities. Redlining and highway construction policies have restricted access to quality health care, increased exposure to carcinogens such as PM2.5, and increased exposure to extreme heat. At the root of these policy decisions are longstanding, toxic societal factors including racism, segregation, and discrimination, which also serve to perpetuate racial inequities in cardiovascular health. Here, we review these societal and structural factors and then link them with biological processes such as telomere shortening, allostatic load, oxidative stress, and tissue inflammation. Lastly, we focus on the impact of inflammation on the immune system and the molecular mechanisms by which the inflamed immune microenvironment promotes the formation of atherosclerotic plaques. We propose that racial residential segregation and discrimination increases tissue inflammation and cytokine production, resulting in dysregulated immune signaling, which promotes plaque formation and cardiovascular disease. This framework has the power to link structural racism not only to cardiovascular disease, but also to cancer.

Increased inflammatory low-density neutrophils in severe obesity and effect of bariatric surgery: Results from case-control and prospective cohort studies.

BACKGROUND: Low-density neutrophils (LDN) are increased in several inflammatory diseases and may also play a role in the low-grade chronic inflammation associated with obesity. Here we explored their role in obesity, determined their gene signatures, and assessed the effect of bariatric surgery. METHODS: We compared the number, function, and gene expression profiles of circulating LDN in morbidly obese patients (MOP, n=27; body mass index (BMI) > 40 Kg/m2) and normal-weight controls (NWC, n=20; BMI < 25 Kg/m2) in a case-control study. Additionally, in a prospective longitudinal study, we measured changes in the frequency of LDN after bariatric surgery (n=36) and tested for associations with metabolic and inflammatory parameters. FINDINGS: LDN and inflammatory markers were significantly increased in MOP compared to NWC. Transcriptome analysis showed increased neutrophil-related gene expression signatures associated with inflammation, neutrophil activation, and immunosuppressive function. However, LDN did not suppress T cells proliferation and produced low levels of reactive oxygen species (ROS). Circulating LDN in MOP significantly decreased after bariatric surgery in parallel with BMI, metabolic syndrome, and inflammatory markers. INTERPRETATION: Obesity increases LDN displaying an inflammatory gene signature. Our results suggest that LDN may represent a neutrophil subset associated with chronic inflammation, a feature of obesity that has been previously associated with the appearance and progression of co-morbidities. Furthermore, bariatric surgery, as an efficient therapy for severe obesity, reduces LDN in circulation and improves several components of the metabolic syndrome supporting its recognized anti-inflammatory and beneficial metabolic effects. FUNDING: This work was supported in part by grants from the National Institutes of Health (NIH; 5P30GM114732-02, P20CA233374 - A. Ochoa and L. Miele), Pennington Biomedical NORC (P30DK072476 - E. Ravussin & LSU-NO Stanley S. Scott Cancer Center and Louisiana Clinical and Translational Science Center (LACaTS; U54-GM104940 - J. Kirwan).

Association of haplotypes of inflammation-related genes with gastric preneoplastic lesions in African Americans and Caucasians.

Identification of biomarkers is needed for development of screening programs to prevent gastric cancer. Because racial differences exist in cancer rates, we aimed to evaluate the association between polymorphisms in inflammation-related genes and gastric preneoplastic lesions in African Americans and Caucasians from Louisiana, USA. Gastric biopsies from 569 adults (361 African Americans and 208 Caucasians) undergoing diagnostic endoscopy were used for histological diagnosis and genomic DNA extraction. Polymorphisms within eight genes (IL1B, IL8, IL6, TNF, PTGS2, ARG1, IL10 and TGFB1) were investigated by TaqMan. The cagA status of Helicobacter pylori infection was assessed by PCR. Haplotype logistic regression models were used to identify variables associated with intestinal metaplasia or dysplasia. African Americans carrying the haplotype IL1B-511T/-31C/+3954T, which includes the three risk-associated alleles at the IL1B locus, were more likely to being diagnosed with intestinal metaplasia or dysplasia than those carrying the most common haplotype T-C-C (adjusted OR: 2.51, 95% CI: 1.1-5.5). None of the polymorphisms were associated with intestinal metaplasia and dysplasia in Caucasians. Age and cagA-positive status were independent factors associated with these lesions. Haplotypes at the IL1B locus may participate in mediating the susceptibility to gastric carcinogenesis and might be useful as markers of advanced premalignant lesions in African Americans. Interestingly, carriage of IL1B+3954T allele seems to be the key factor, even though the role played by other polymorphisms cannot be excluded.

Arginase I in myeloid suppressor cells is induced by COX-2 in lung carcinoma.

Myeloid suppressor cells (MSCs) producing high levels of arginase I block T cell function by depleting l-arginine in cancer, chronic infections, and trauma patients. In cancer, MSCs infiltrating tumors and in circulation are an important mechanism for tumor evasion and impair the therapeutic potential of cancer immunotherapies. However, the mechanisms that induce arginase I in MSCs in cancer are unknown. Using the 3LL mouse lung carcinoma, we aimed to characterize these mechanisms. Arginase I expression was independent of T cell-produced cytokines. Instead, tumor-derived soluble factors resistant to proteases induced and maintained arginase I expression in MSCs. 3LL tumor cells constitutively express cyclooxygenase (COX)-1 and COX-2 and produce high levels of PGE2. Genetic and pharmacological inhibition of COX-2, but not COX-1, blocked arginase I induction in vitro and in vivo. Signaling through the PGE2 receptor E-prostanoid 4 expressed in MSCs induced arginase I. Furthermore, blocking arginase I expression using COX-2 inhibitors elicited a lymphocyte-mediated antitumor response. These results demonstrate a new pathway of prostaglandin-induced immune dysfunction and provide a novel mechanism that can help explain the cancer prevention effects of COX-2 inhibitors. Furthermore, an addition of arginase I represents a clinical approach to enhance the therapeutic potential of cancer immunotherapies.

Obesity-Associated Myeloid Immunosuppressive Cells, Key Players in Cancer Risk and Response to Immunotherapy.

Obesity is a risk factor for developing several cancers. The dysfunctional metabolism and chronic activation of inflammatory pathways in obesity create a milieu that supports tumor initiation, progression, and metastasis. Obesity-associated metabolic, endocrine, and inflammatory mediators, besides interacting with cells leading to a malignant transformation, also modify the intrinsic metabolic and functional characteristics of immune myeloid cells. Here, the evidence supporting the hypothesis that obesity metabolically primes and promotes the expansion of myeloid cells with immunosuppressive and pro-oncogenic properties is discussed. In consequence, the accumulation of these cells, such as myeloid-derived suppressor cells and some subtypes of adipose-tissue macrophages, creates a microenvironment conducive to tumor development. In this review, the role of lipids, insulin, and leptin, which are dysregulated in obesity, is emphasized, as well as dietary nutrients in metabolic reprogramming of these myeloid cells. Moreover, emerging evidence indicating that obesity enhances immunotherapy response and hypothesized mechanisms are summarized. Priorities in deeper exploration involving the mechanisms of cross talk between metabolic disorders and myeloid cells related to cancer risk in patients with obesity are highlighted.