Racial differences in weight perception among Black and White women diagnosed with breast cancer

PURPOSE

Black women are more likely than White women to have obesity, and obesity is associated with worse breast cancer prognosis. Weight perception, however, has not been studied as a potential mediator of obesity disparities in women with breast cancer. In this study, we sought to describe racial differences and the association of lifestyle factors with weight perception.

METHODS

In this cross-sectional study design, Black and White women with a new primary breast cancer were surveyed about socio-demographics, weight perception, diet, and exercise habits. Height and weight were measured at enrollment. We classified women with a BMI ≥ 25 kg/m2 or waist circumference ≥ 88 cm who reported that they were "about the right weight" as under-perceivers. Chi-square and t tests were used to assess study variables (e.g., race, physical activity) associated with under-perception of weight. Logistic regression models were fit to evaluate for racial differences in under-perception while controlling for other covariates.

RESULTS

Of 1,197 women with newly diagnosed breast cancer, the average age was 58 years, and 909 (75.9%) were White. Nine hundred eighteen (77%) had stage I cancer, 1,035 (87%) had estrogen receptor positive cancer, and 795 (66%) were privately insured at time of diagnosis. Seven hundred eighty-nine (66%) women had abdominal obesity (waist circumference ≥ 88 cm), while 366 (31%) women had a BMI ≥ 25 kg/m2. Overall, 24% of women were under-perceivers. Compared to White women, Black women with WC ≥ 88 cm more frequently under-perceived their weight (24% vs. 14% p < 0.0001) were more obese with BMI > 30 kg/m2 (51% vs. 23%, p < 0.0001) and had lower physical activity (22% vs. 77%, p < 0.0001). After controlling for age, education, and stage, Black women remained more likely to under-perceive their weight relative to White women for those with BMI ≥ 25 kg/m2 (OR: 2.64; 95% CI: 1.4-4.6) or waist circumference ≥ 88 cm (OR: 2.89; 95% CI: 1.8-4.5). With respect to lifestyle factors, among women with BMI ≥ 25 kg/m2, those who met physical activity guidelines were less likely to under-perceive their weight compared to those who did not meet physical activity guidelines (OR: 0.37; 95% CI: 0.2-0.6), regardless of race.

CONCLUSIONS

We found racial differences in weight perception and identified social determinants and lifestyle factors such as lower education and physical inactivity that influenced under-perception of weight among newly diagnosed breast cancer patients.

IMPLICATIONS FOR CANCER SURVIVORS

Since obesity is associated with worse breast cancer outcomes, identifying optimal modifiable factors to intervene upon to support weight management among breast cancer survivors is clinically important. Breast cancer patients' perceptions about their weight provide insight that may inform lifestyle behavior interventions to reduce obesity during survivorship care.

Impact of diabetes on stage I lung cancer treatment patterns and prognosis in older adults: A population-based cohort study

Background

Diabetes is a common comorbidity in patients with early-stage non-small cell lung cancer (NSCLC), a growing population due to increased LC screening. However, it is unknown if diabetes is associated with less aggressive NSCLC treatment and worse NSCLC outcomes. This study aimed to investigate treatment patterns and outcomes of older patients with Stage I NSCLC and diabetes.

Methods

Using national cancer registry data linked to Medicare, we identified patients ≥65 years old with Stage I NSCLC. Patients were categorized as having no diabetes, diabetes without severe complications (DM-c), or diabetes with ≥1 severe complication (DM + c). We used multinomial logistic regression to assess the association of diabetes and NSCLC treatment. The association of diabetes category with NSCLC and non-NSCLC survival was analyzed with Fine-Grey competing-risks regression.

Results

In 25,358 patients (75% no diabetes, 12% DM-c and 13% had DM + c), adjusted analyses showed that DM-c and DM + c were associated with increased odds of receiving limited resection rather than lobectomy (odds ratio [OR]: 1.22, 95% confidence interval [CI]: 1.07-1.37 and OR 1.42, 95% CI 1.26-1.59, respectively). Competing risk regression showed diabetes was associated with increased risk of non-NSCLC death (DM-c hazard ratio [HR] 1.16, 95% CI: 1.08-1.25, DM + c HR 1.49, 95% CI: 1.40-1.59), but not NSCLC-specific death.

Conclusion

This study uncovers critical information on how diabetes is associated with less aggressive early-stage NSCLC care in older patients. This study also confirms that diabetes increases death from non-lung cancer causes and managing comorbidities is crucial to improving outcomes in older early-stage NSCLC survivors.

Glucagon-like peptide-1: a multi-faceted anti-inflammatory agent

Inflammation contributes to many chronic conditions. It is often associated with circulating pro-inflammatory cytokines and immune cells. GLP-1 levels correlate with disease severity. They are often elevated and can serve as markers of inflammation. Previous studies have shown that oxytocin, hCG, ghrelin, alpha-MSH and ACTH have receptor-mediated anti-inflammatory properties that can rescue cells from damage and death. These peptides have been studied well in the past century. In contrast, GLP-1 and its anti-inflammatory properties have been recognized only recently. GLP-1 has been proven to be a useful adjuvant therapy in type-2 diabetes mellitus, metabolic syndrome, and hyperglycemia. It also lowers HbA1C and protects cells of the cardiovascular and nervous systems by reducing inflammation and apoptosis. In this review we have explored the link between GLP-1, inflammation, and sepsis.

Subjective social status, race, and metabolic syndrome in women with breast cancer

PURPOSE

To evaluate the association of subjective social status (SSS) with metabolic syndrome (MetS) severity and its potential contribution to racial health disparities in women with breast cancer.

METHODS

Multicenter cross-sectional study (10 US hospitals) in women (n = 1206) with primary diagnosis of invasive breast cancer received during Mar/2013-Feb/2020. Participants, self-identified as non-Hispanic White or Black, underwent physical and laboratory examinations and survey questions assessing socioeconomic parameters, medical history, and behavioral risks. SSS was measured with the 10-rung MacArthur scale. MetS severity was measured with a validated Z-Score. Generalized linear mixed modeling was used to analyze the associations. Missing data were handled using multiple imputation.

RESULTS

Average age was 58 years. On average, the SSS of Black women, given equivalent level of income and education, was lower than the SSS of White women: 6.6 (6.1-7.0) vs 7.7 (7.54-7.79) among college graduates and 6.8 (6.4-7.2) vs 7.6 (7.5-7.8) among women in the high-income category (> $75,000). In multivariable analysis, after controlling for age, income, education, diet, and physical activity, increasing SSS was associated with a decrease in MetS-Z score, - 0.10 (- 0.16 to - 0.04) per every 2 rung increase in the MacArthur scale.

CONCLUSION

Black women with breast cancer rank their SSS lower than White women with breast cancer do at each level of income and education. As SSS is strongly associated with MetS severity these results identify potentially modifiable factors that contribute to racial disparities.

Management of Type 2 Diabetes Mellitus in the Very Elderly: One Practice's Experience

OBJECTIVE

Type 2 diabetes mellitus (T2DM) affects 25% of adults over age 65. Nevertheless, few clinical trials include patients over age 75.

METHODS

This case series reports retrospective data on a cohort of 85 patients aged 80 and over (mean 88.1, range 80-104) with T2DM, managed by a single endocrinologist. The practice's computerized data base was searched for all patients 80 years of age and older with a diagnosis of T2DM.

RESULTS

The major observations were the significant decrease in the use of agents associated with hypoglycemia, (sulfonylureas and insulin), and the beneficial and well-tolerated use of glucagon like peptide-1 receptor analogues (GLP-1 RA). The mean A1c in the entire cohort dropped from 7.6% to 6.6% over a mean of 9 months. Nearly one-half of the cohort were treated with GLP1-RA, reflecting studies demonstrating the safety and efficacy of this class of drugs in less elderly patients. At presentation, 75% were on sulfonylurea and/or insulin; this number was reduced to 27%. Furthermore, none of the patients required short-acting (bolus) insulin to achieve the individualized A1c target.

CONCLUSION

Patients with T2DM aged 80 and over respond well to GLP1-RA drugs, drastically reducing the need for agents associated with hypoglycemia. The important question, which will require larger and prospective studies, is whether the lowering of A1c, as shown in this paper, and the use of GLP-1 RA specifically, are associated with improved morbidity and mortality in the very elderly.

Unregulated LDL cholesterol uptake is detrimental to breast cancer cells

Tumor uptake of exogenous cholesterol has been associated with the proliferation of various cancers. Previously, we and others have shown that hypercholesterolemia promotes tumor growth and silencing of the LDL receptor (LDLR) in high LDLR-expressing tumors reduces growth. To advance understanding of how LDL uptake promotes tumor growth, LDLR expression was amplified in breast cancer cell lines with endogenously low LDLR expression. Murine (Mvt1) and human (MDA-MB-468) breast cancer cell lines were transduced to overexpress human LDLR (LDLROE). Successful transduction was confirmed by RNA and protein analysis. Fluorescence-labeled LDL uptake was increased in both Mvt1 and MDA-MD-468 LDLROE cells. The expression of the cholesterol-metabolizing genes, ABCA1 and ABCG1, was increased, while HMGCR was decreased in the MDA-MB-468 LDLROE cells. In contrast, Mvt1 LDLROE cells showed no differences in Abca1 and Abcg1 expression and increased Hmgcr expression. Using a Seahorse analyzer, Mvt1 LDLROE cells showed increased respiration (ATP-linked and maximal) relative to controls, while no statistically significant changes in respiration in MDA-MB-468 LDLROE cells were observed. Growth of LDLROE cells was reduced in culture and in hypercholesterolemic mice by two-fold. However, the expression of proliferation-associated markers (Ki67, PCNA and BrdU-label incorporation) was not decreased in the Mvt1 LDLROE tumors and cells. Caspase-3 cleavage, which is associated with apoptosis, was increased in both the Mvt1 and MDA-MB-468 LDLROE cells relative to controls, with the Mvt1 LDLROE cells also showing decreased phosphorylation of p44/42MAPK. Taken together, our work suggests that while additional LDL can promote tumor growth, unregulated and prolonged LDL uptake is detrimental.

Breast tumor IGF1R regulates cell adhesion and metastasis: alignment of mouse single cell and human breast cancer transcriptomics

Introduction

The acquisition of a metastatic phenotype is the critical event that determines patient survival from breast cancer. Several receptor tyrosine kinases have functions both in promoting and inhibiting metastasis in breast tumors. Although the insulin-like growth factor 1 receptor (IGF1R) has been considered a target for inhibition in breast cancer, low levels of IGF1R expression are associated with worse overall patient survival.

Methods

To determine how reduced IGF1R impacts tumor phenotype in human breast cancers, we used weighted gene co-expression network analysis (WGCNA) of Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) patient data to identify gene modules associated with low IGF1R expression. We then compared these modules to single cell gene expression analyses and phenotypes of mouse mammary tumors with reduced IGF1R signaling or expression in a tumor model of triple negative breast cancer.

Results

WGCNA from METABRIC data revealed gene modules specific to cell cycle, adhesion, and immune cell signaling that were inversely correlated with IGF1R expression in human breast cancers. Integration of human patient data with single cell sequencing data from mouse tumors revealed similar pathways necessary for promoting metastasis in basal-like mammary tumors with reduced signaling or expression of IGF1R. Functional analyses revealed the basis for the enhanced metastatic phenotype including alterations in E- and P-cadherins.

Discussion

Human breast and mouse mammary tumors with reduced IGF1R are associated with upregulation of several pathways necessary for promoting metastasis supporting the conclusion that IGF1R normally helps maintain a metastasis suppressive tumor microenvironment. We further found that reduced IGF1R signaling in tumor epithelial cells dysregulates cadherin expression resulting in reduced cell adhesion.

Insulin resistance and racial disparities in breast cancer prognosis: a multi-center cohort study

The survival for breast cancer (BC) is improving but remains lower in Black women than White women. A number of factors potentially drive the racial differences in BC outcomes. The aim of our study was to determine if insulin resistance (defined as homeostatic model assessment for insulin resistance (HOMA-IR)), mediated part of the relationship between race and BC prognosis (defined by the improved Nottingham prognostic index (iNPI)). We performed a cross-sectional study, recruiting self-identified Black and White women with newly diagnosed primary invasive BC from 10 US hospitals between March 2013 and February 2020. Survey, anthropometric, laboratory, and tumor pathology data were gathered, and we compared the results between Black and White women. We calculated HOMA-IR as well as iNPI scores and examined the associations between HOMA-IR and iNPI. After exclusions, the final cohort was 1206: 911 (76%) White and 295 (24%) Black women. Metabolic syndrome and insulin resistance were more common in Black than White women. Black women had less lobular BC, three times more triple-negative BC, and BCs with higher stage and iNPI scores than White women (P < 0.001 for all comparisons). Fewer Black women had BC genetic testing performed. HOMA-IR mediated part of the association between race and iNPI, particularly in BCs that carried a good prognosis and were hormone receptor (HR)-positive. Higher HOMA-IR scores were associated with progesterone receptor-negative BC in White women but not Black women. Overall, our results suggest that HOMA-IR contributes to the racial disparities in BC outcomes, particularly for women with HR-positive BCs.

Hallmarks of cancer: The insulin-like growth factors perspective

The identification of a series of attributes or hallmarks that are shared by virtually all cancer cells constitutes a true milestone in cancer research. The conceptualization of a catalogue of common genetic, molecular, biochemical and cellular events under a unifying Hallmarks of Cancer idea had a major impact in oncology. Furthermore, the fact that different types of cancer, ranging from pediatric tumors and leukemias to adult epithelial cancers, share a large number of fundamental traits reflects the universal nature of the biological events involved in oncogenesis. The dissection of a complex disease like cancer into a finite directory of hallmarks is of major basic and translational relevance. The role of insulin-like growth factor-1 (IGF1) as a progression/survival factor required for normal cell cycle transition has been firmly established. Similarly well characterized are the biochemical and cellular activities of IGF1 and IGF2 in the chain of events leading from a phenotypically normal cell to a diseased one harboring neoplastic traits, including growth factor independence, loss of cell-cell contact inhibition, chromosomal abnormalities, accumulation of mutations, activation of oncogenes, etc. The purpose of the present review is to provide an in-depth evaluation of the biology of IGF1 at the light of paradigms that emerge from analysis of cancer hallmarks. Given the fact that the IGF1 axis emerged in recent years as a promising therapeutic target, we believe that a careful exploration of this signaling system might be of critical importance on our ability to design and optimize cancer therapies.

Distinct cord blood C-peptide, adipokine, and lipidomic signatures by in utero HIV exposure

BACKGROUND

Early-life metabolic derangements in HIV-exposed uninfected (HEU) infants have been reported.

METHODS

Pregnant women with HIV and HIV-uninfected pregnant women were enrolled with their newborns in a US cohort from 2011 to 2015. We measured cord insulin, C-peptide, and metabolic cytokines of HEU and HIV-unexposed uninfected (HUU) newborns using ELISA and metabolites, lipid subspecies, and eicosanoids via liquid chromatography/mass spectrometry. Linear regression was employed to assess the association of intrauterine HIV/ART with insulin and C-peptide. Graphical lasso regression was used to identify differences between metabolite/lipid subspecies networks associated with C-peptide.

RESULTS

Of 118 infants, 56 were HEU, ART exposed. In adjusted analyses, mean cord insulin (β = 0.295, p = 0.03) and C-peptide (β = 0.522, p < 0.01) were significantly higher in HEU vs. HUU newborns. HEU neonates exhibited primarily positive associations between complex lipids and C-peptide, indicative of fuel storage, and augmented associations between cord eicosanoids and cytokines. HUU neonates exhibited negative associations with lipids and C-peptide indicative of increased fuel utilization.

CONCLUSION

Higher cord insulin and C-peptide in HEU vs. HUU newborns as well as differences in cord metabolites, metabolic-related cytokines, and eicosanoids may reflect a propensity for fuel storage and an inflammatory milieu suggestive of fetal metabolic changes associated with in utero HIV/ART exposure.

IMPACT

There is a paucity of studies assessing cord blood and neonatal metabolic health in HIV-exposed uninfected (HEU) newborns, an increasing population worldwide. Compared to HIV-unexposed uninfected (HUU) newborns, HEU newborns exhibit alterations in fuel homeostasis and an inflammatory milieu associated with in utero HIV/antiretroviral therapy (ART) exposure. The long-term implications of these neonatal findings are as yet unknown, but merit continued evaluation as this important and growing population ages into adulthood.

Distinct Lipidomic Signatures in People Living With HIV: Combined Analysis of ACTG 5260s and MACS/WIHS

CONTEXT

Disentangling contributions of HIV from antiretroviral therapy (ART) and understanding the effects of different ART on metabolic complications in persons living with HIV (PLHIV) has been challenging.

OBJECTIVE

We assessed the effect of untreated HIV infection as well as different antiretroviral therapy (ART) on the metabolome/lipidome.

METHODS

Widely targeted plasma metabolomic and lipidomic profiling was performed on HIV-seronegative individuals and people living with HIV (PLHIV) before and after initiating ART (tenofovir/emtricitabine plus atazanavir/ritonavir [ATV/r] or darunavir/ritonavir [DRV/r] or raltegravir [RAL]). Orthogonal partial least squares discriminant analysis was used to assess metabolites/lipid subspecies that discriminated between groups. Graphical lasso estimated group-specific metabolite/lipid subspecies networks associated with the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Correlations between inflammatory markers and metabolites/lipid subspecies were visualized using heat maps.

RESULTS

Of 435 participants, 218 were PLHIV. Compared to HIV-seronegative individuals, ART-naive PLHIV exhibited higher levels of saturated triacylglycerols/triglycerides (TAGs) and 3-hydroxy-kynurenine, lower levels of unsaturated TAGs and N-acetyl-tryptophan, and a sparser and less heterogeneous network of metabolites/lipid subspecies associated with HOMA-IR. PLHIV on RAL vs ATV/r or DRV/r had lower saturated and unsaturated TAGs. Positive correlations were found between medium-long chain acylcarnitines (C14-C6 ACs), palmitate, and HOMA-IR for RAL but not ATV/r or DRV/r. Stronger correlations were seen for TAGs with interleukin 6 and high-sensitivity C-reactive protein after RAL vs ATV/r or DRV/r initiation; these correlations were absent in ART-naive PLHIV.

CONCLUSION

Alterations in the metabolome/lipidome suggest increased lipogenesis for ART-naive PLHIV vs HIV-seronegative individuals, increased TAG turnover for RAL vs ATV/r or DRV/r, and increased inflammation associated with this altered metabolome/lipidome after initiating ART. Future studies are needed to understand cardiometabolic consequences of lipogenesis and inflammation in PLHIV.

Oxytocin and Related Peptide Hormones: Candidate Anti-Inflammatory Therapy in Early Stages of Sepsis

Sepsis is a potentially life-threatening systemic inflammatory syndrome characterized by dysregulated host immunological responses to infection. Uncontrolled immune cell activation and exponential elevation in circulating cytokines can lead to sepsis, septic shock, multiple organ dysfunction syndrome, and death. Sepsis is associated with high re-hospitalization and recovery may be incomplete, with long term sequelae including post-sepsis syndrome. Consequently, sepsis continues to be a leading cause of morbidity and mortality across the world. In our recent review of human chorionic gonadotropin (hCG), we noted that its major properties including promotion of fertility, parturition, and lactation were described over a century ago. By contrast, the anti-inflammatory properties of this hormone have been recognized only more recently. Vasopressin, a hormone best known for its anti-diuretic effect, also has anti-inflammatory actions. Surprisingly, vasopressin's close cousin, oxytocin, has broader and more potent anti-inflammatory effects than vasopressin and a larger number of pre-clinical studies supporting its potential role in limiting sepsis-associated organ damage. This review explores possible links between oxytocin and related octapeptide hormones and sepsis-related modulation of pro-inflammatory and anti-inflammatory activities.

Assessing the association of diabetes with lung cancer risk

BACKGROUND

Diabetes is a well-established risk factor for many cancers, but its relationship with lung cancer incidence remains unclear. In this study, we aimed to assess if diabetes is independently associated with lung cancer risk and histology subtype among participants in a screening study.

METHODS

In a retrospective cohort study using data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) study, we assessed the association of self-reported diabetes with lung cancer incidence using Poisson regression while adjusting for other established risk factors in the PLCOM2012, a validated lung cancer prediction model. The adjusted association of diabetes and lung cancer cell type was evaluated using nominal regression. Stratified analyses were also conducted according to sex, smoking history, and body mass index categories.

RESULTS

Overall, 140,395 participants were included in our analysis. Diabetes was not significantly associated with lung cancer incidence [incidence rate ratio (IRR): 1.03, 95% confidence interval (CI): 0.91-1.17]. Similarly, stratified analyses also did not show significant associations between diabetes and lung cancer risk (all P values >0.05). We found no significant difference in the distribution of lung cancer histology in participants with vs. without diabetes (P=0.30).

CONCLUSIONS

Diabetes was not an independent risk factor for lung cancer in a large cohort of PLCO participants. We did not observe differences in histology according to diabetes status. These results suggest that patients with diabetes do not need more aggressive lung cancer screening. Future research including more detailed metabolic parameters may further elucidate the relationship between metabolic disease and lung cancer risk.

GLUT4-overexpressing engineered muscle constructs as a therapeutic platform to normalize glycemia in diabetic mice

Skeletal muscle insulin resistance is a main defect in type 2 diabetes (T2D), which is associated with impaired function and content of glucose transporter type 4 (GLUT4). GLUT4 overexpression in skeletal muscle tissue can improve glucose homeostasis. Therefore, we created an engineered muscle construct (EMC) composed of GLUT4-overexpressing (OEG4) cells. The ability of the engineered implants to reduce fasting glucose levels was tested in diet-induced obesity mice. Decrease and stabilization of basal glucose levels were apparent up to 4 months after implantation. Analysis of the retrieved constructs showed elevated expression of myokines and proteins related to metabolic processes. In addition, we validated the efficiency of OEG4-EMCs in insulin-resistant mice. Following high glucose load administration, mice showed improved glucose tolerance. Our data indicate that OEG4-EMC implant is an efficient mode for restoring insulin sensitivity and improving glucose homeostasis in diabetic mice. Such procedure is a potential innovative modality for T2D therapy.

Insulin-like growth factors: Ligands, binding proteins, and receptors

BACKGROUND

The insulin-like growth factor family of ligands (IGF-I, IGF-II, and insulin), receptors (IGF-IR, M6P/IGF-IIR, and insulin receptor [IR]), and IGF-binding proteins (IGFBP-1-6) play critical roles in normal human physiology and disease states.

SCOPE OF REVIEW

Insulin and insulin receptors are the focus of other chapters in this series and will therefore not be discussed further. Here we review the basic components of the IGF system, their role in normal physiology and in critical pathology's. While this review concentrates on the role of IGFs in human physiology, animal models have been essential in providing understanding of the IGF system, and its regulation, and are briefly described.

MAJOR CONCLUSIONS

IGF-I has effects via the circulation and locally within tissues to regulate cellular growth, differentiation, and survival, thereby controlling overall body growth. IGF-II levels are highest prenatally when it has important effects on growth. In adults, IGF-II plays important tissue-specific roles, including the maintenance of stem cell populations. Although the IGF-IR is closely related to the IR it has distinct physiological roles both on the cell surface and in the nucleus. The M6P/IGF-IIR, in contrast, is distinct and acts as a scavenger by mediating internalization and degradation of IGF-II. The IGFBPs bind IGF-I and IGF-II in the circulation to prolong their half-lives and modulate tissue access, thereby controlling IGF function. IGFBPs also have IGF ligand-independent cell effects.

Association of Insulin Resistance and Higher Oncotype DX™ Recurrence Score

BACKGROUND

Black women with breast cancer have a worse overall survival compared with White women; however, no difference in Oncotype DX™ (ODX) recurrence scores has been observed to explain this health disparity. Black women are also disproportionately affected by insulin resistance. We evaluated whether insulin resistance is associated with a higher ODX recurrence score and whether there is a difference between White and Black women to explain disparate clinical outcomes.

METHODS

A subgroup analysis of patients in a multi-institutional cross-sectional study evaluating differences in insulin resistance between White and Black women was performed. Women diagnosed with a new hormone receptor-positive, HER2/neu-negative breast cancer with an ODX recurrence score were identified. Fasting blood glucose and insulin measurements were used to calculate the homeostatic model assessment of insulin resistance (HOMA-IR) score, a method for assessing insulin resistance, and compared against ODX scores.

RESULTS

Overall, 412 women (358 White women, 54 Black women) were identified. Compared with White women, Black women had a higher body mass index (30 vs. 26 kg/m², p < 0.0001), higher HOMA-IR score (2.4 vs. 1.4, p = 0.004), and more high-grade tumors (30% vs. 16%, p = 0.01). There was a direct positive association with an increasing ODX score and HOMA-IR (p = 0.014). On subset analysis, this relationship was seen in White women (p = 0.005), but not in Black women (p = 0.55).

CONCLUSION

In women with newly diagnosed breast cancer, increasing insulin resistance is associated with a higher recurrence score; however, this association was not present in Black women. This lack of association may be due to the small number of Black women in the cohort, or possibly a reflection of a different biological disease process of the patient's tumor.

Obesity, Type 2 Diabetes, and Cancer Risk

Obesity and type 2 diabetes have both been associated with increased cancer risk and are becoming increasingly prevalent. Metabolic abnormalities such as insulin resistance and dyslipidemia are associated with both obesity and type 2 diabetes and have been implicated in the obesity-cancer relationship. Multiple mechanisms have been proposed to link obesity and diabetes with cancer progression, including an increase in insulin/IGF-1 signaling, lipid and glucose uptake and metabolism, alterations in the profile of cytokines, chemokines, and adipokines, as well as changes in the adipose tissue directly adjacent to the cancer sites. This review aims to summarize and provide an update on the epidemiological and mechanistic evidence linking obesity and type 2 diabetes with cancer, focusing on the roles of insulin, lipids, and adipose tissue.

The midlife transition and the risk of cardiovascular disease and cancer Part I: magnitude and mechanisms

Heart disease and cancer are the leading causes of death in the United States. In women, the clinical appearance of both entities-coronary heart disease and cancer (breast, endometrium, and ovary)-escalate during the decades of the midlife transition encompassing the menopause. In addition to the impact of aging, during the interval between the age of 40 and 65 years, the pathophysiologic components of metabolic syndrome also emerge and accelerate. These include visceral adiposity (measured as waist circumference), hypertension, diabetes, and dyslipidemia. Osteoporosis, osteoarthritis, sarcopenia, depression, and even cognitive decline and dementia appear, and most, if not all, are considered functionally related. Two clinical reports confirm the interaction linking the emergence of disease: endometrial cancer and metabolic syndrome. One describes the discovery of unsuspected endometrial cancer in a large series of elective hysterectomies performed in aged and metabolically susceptible populations. The other is from the Women's Health Initiative Observational Study, which found a positive interaction between endometrial cancer and metabolic syndrome regardless of the presence or absence of visceral adiposity. Both provide additional statistical support for the long-suspected causal interaction among the parallel but variable occurrence of these common entities-visceral obesity, heart disease, diabetes, cancer, and the prevalence of metabolic syndrome. Therefore, 2 critical clinical questions require analysis and answers: 1: Why do chronic diseases of adulthood-metabolic, cardiovascular, endocrine-and, in women, cancers of the breast and endometrium (tissues and tumors replete with estrogen receptors) emerge and their incidence trajectories accelerate during the postmenopausal period when little or no endogenous estradiol is available, and yet the therapeutic application of estrogen stimulates their appearance? 2: To what extent should identification of these etiologic driving forces require modification of the gynecologist's responsibilities in the care of our patients in the postreproductive decades of the female life cycle? Part l of this 2-part set of "expert reviews" defines the dimensions, gravity, and interactive synergy of each clinical challenge gynecologists face while caring for their midlife (primarily postmenopausal) patients. It describes the clinically identifiable, potentially treatable, pathogenic mechanisms driving these threats to quality of life and longevity. Part 2 (accepted, American Journal of Obstetrics & Gynecology) identifies 7 objectives of successful clinical care, offers "triage" prioritization targets, and provides feasible opportunities for insertion of primary preventive care initiatives. To implement these goals, a reprogrammed, repurposed office visit is described.

Hyperinsulinaemia in cancer

Elevated circulating insulin levels are frequently observed in the setting of obesity and early type 2 diabetes, as a result of insensitivity of metabolic tissues to the effects of insulin. Higher levels of circulating insulin have been associated with increased cancer risk and progression in epidemiology studies. Elevated circulating insulin is believed to be a major factor linking obesity, diabetes and cancer. With the development of targeted cancer therapies, insulin signalling has emerged as a mechanism of therapeutic resistance. Although metabolic tissues become insensitive to insulin in the setting of obesity, a number of mechanisms allow cancer cells to maintain their ability to respond to insulin. Significant progress has been made in the past decade in understanding the insulin receptor and its signalling pathways in cancer, and a number of lessons have been learnt from therapeutic failures. These discoveries have led to numerous clinical trials that have aimed to reduce the levels of circulating insulin and to abrogate insulin signalling in cancer cells. With the rising prevalence of obesity and diabetes worldwide, and the realization that hyperinsulinaemia may contribute to therapeutic failures, it is essential to understand how insulin and insulin receptor signalling promote cancer progression.

Insulin resistance contributes to racial disparities in breast cancer prognosis in US women

Background

Racial disparities in breast cancer survival between Black and White women persist across all stages of breast cancer. The metabolic syndrome (MetS) of insulin resistance disproportionately affects more Black than White women. It has not been discerned if insulin resistance mediates the link between race and poor prognosis in breast cancer. We aimed to determine whether insulin resistance mediates in part the association between race and breast cancer prognosis, and if insulin receptor (IR) and insulin-like growth factor receptor (IGF-1R) expression differs between tumors from Black and White women.

Methods

We conducted a cross-sectional, multi-center study across ten hospitals. Self-identified Black women and White women with newly diagnosed invasive breast cancer were recruited. The primary outcome was to determine if insulin resistance, which was calculated using the homeostatic model assessment of insulin resistance (HOMA-IR), mediated the effect of race on prognosis using the multivariate linear mediation model. Demographic data, anthropometric measurements, and fasting blood were collected. Poor prognosis was defined as a Nottingham Prognostic Index (NPI) > 4.4. Breast cancer pathology specimens were evaluated for IR and IGF-1R expression by immunohistochemistry (IHC).

Results

Five hundred fifteen women were recruited (83% White, 17% Black). The MetS was more prevalent in Black women than in White women (40% vs 20%, p < 0.0001). HOMA-IR was higher in Black women than in White women (1.9 ± 1.2 vs 1.3 ± 1.4, p = 0.0005). Poor breast cancer prognosis was more prevalent in Black women than in White women (28% vs 15%. p = 0.004). HOMA-IR was positively associated with NPI score (r = 0.1, p = 0.02). The mediation model, adjusted for age, revealed that HOMA-IR significantly mediated the association between Black race and poor prognosis (β = 0.04, 95% CI 0.005–0.009, p = 0.002). IR expression was higher in tumors from Black women than in those from White women (79% vs 52%, p = 0.004), and greater IR/IGF-1R ratio was also associated with higher NPI score (IR/IGF-1R >  1: 4.2 ± 0.8 vs IR/IGF-1R = 1: 3.9 ± 0.8 vs IR/IGF-1R < 1: 3.5 ± 1.0, p < 0.0001).

Conclusions

In this multi-center, cross-sectional study of US women with newly diagnosed invasive breast cancer, insulin resistance is one factor mediating part of the association between race and poor prognosis in breast cancer.

Dietary Intake Regulates the Circulating Inflammatory Monocyte Pool

Caloric restriction is known to improve inflammatory and autoimmune diseases. However, the mechanisms by which reduced caloric intake modulates inflammation are poorly understood. Here we show that short-term fasting reduced monocyte metabolic and inflammatory activity and drastically reduced the number of circulating monocytes. Regulation of peripheral monocyte numbers was dependent on dietary glucose and protein levels. Specifically, we found that activation of the low-energy sensor 5'-AMP-activated protein kinase (AMPK) in hepatocytes and suppression of systemic CCL2 production by peroxisome proliferator-activator receptor alpha (PPARα) reduced monocyte mobilization from the bone marrow. Importantly, we show that fasting improves chronic inflammatory diseases without compromising monocyte emergency mobilization during acute infectious inflammation and tissue repair. These results reveal that caloric intake and liver energy sensors dictate the blood and tissue immune tone and link dietary habits to inflammatory disease outcome.

SAT-151 Regulation of Low-Density Lipoprotein Receptor Expression in Triple Negative Breast Cancer

Preclinical models and clinical studies suggest that hypercholesterolemia promotes breast cancer progression ^1,2. The expression of the low-density lipoprotein receptor (LDLR) has been positively associated with poorer recurrence-free survival in human breast cancer studies ³. Mechanistically, LDLR has been demonstrated to play a role in the increased tumor growth associated with hypercholesterolemia, as knock-down of LDLR led to decreased tumor growth in setting of elevated circulating LDL cholesterol. The aim of this study was to identify factors which up-regulate expression of LDLR in triple negative breast cancer (TNBC). In glioblastoma, hyper-activation of the epidermal growth factor receptor (EGFR) signaling pathway has been associated with greater LDLR expression and susceptibility to targeting of cholesterol metabolism⁴. As EGFR is frequently expressed in TNBC⁵, we examined if increased LDLR expression is associated with activation of the EGFR signaling pathway in TNBC. The expression of LDLR in the TNBC cell lines, MDA-MB-231 (231) and MDA-MB-468 (468) was examined pre- and post-EGF stimulation of the EGFR and in the presence of chemical inhibitors. Cells were grown in DMEM/10% FBS/1% Pen/strep (P/S), and experiments were performed under reduced serum conditions at 1.25%FBS/DMEM/1%P/S. In the absence of stimulation, LDLR protein expression was 3-fold higher in 231 vs 468 cell lines. This was despite mRNA expression being comparable at baseline, suggesting that the difference in protein expression was post-transcriptionally mediated. Treatment with 10 ng/mL EGF for 2 hours led to an increased activation of the EGFR, phosphorylation of Akt and extracellular signal regulated kinase (ERK) in both cell lines but induced an increase in LDLR protein and mRNA expression only in 468 cells. Treatment of 468 cells with EGF after exposure to actinomycin, a transcription inhibitor, revealed that EGF treatment resulted in reduced degradation of LDLR mRNA (p = 0.002) over 3 hours, suggesting that the EGF-induced increase in LDLR expression was by protection of LDLR mRNA from degradation. Chemical inhibition of the ERK pathway with 20 μM UO126 reduced both the EGF-induced increase in LDLR expression in 468 cells (p = 0.015) as well as the high baseline expression of LDLR by half in 231 cells (p = 0.001). Overall our results suggest that the EGFR/ERK signaling pathway regulates LDLR expression in TNBC, supporting the increased anabolic needs of this aggressive, swiftly expanding form of breast cancer.

References:¹Alikhani, N. et al., Oncogene32, 961-967 (2013), ²Pelton, K. et al., Am. J. Pathol.184, 2099-2110 (2014), ³Gallagher, E. J. et al., Oncogene36, 6462-6471 (2017), ⁴Guo, D. et al., Cancer Discov.1, 442-456 (2011), ⁵Reis‐Filho, J. S. & Tutt, A. N. J. Histopathology52, 108-118 (2008).

SUN-131 The Roles of Two Insulin Receptor Isoforms in Triple Negative Breast Cancer Growth

Systemic hyperinsulinemia is believed to be an important factor in the progression of a number of cancers, including breast cancer by activating the insulin receptor (IR) signaling cascade in the tumor cells. The IR is expressed in two isoforms, IR-A and IR-B. IR-B is the full-length isoform, while IR-A is lacking 12 amino acids in the α-subunit due to exon 11 alternative splicing. IR-A is predominantly expressed in cancer tissues, while IR-B is mostly expressed in metabolic tissues. The IR and closely related insulin-like growth factor 1 receptor (IGF-1R) are expressed in different ratios in cancer cells. Compared with estrogen receptor positive breast cancers, triple negative breast cancers (TNBC) frequently have higher ratios of IR to IGF-1R. Hyperinsulinemia is associated with increased prevalence of TNBC in pre-menopausal women. Although new targeted therapies are emerging, among breast cancer subtypes TNBC continues to carry the worst prognosis and therefore developing a greater understanding of the links between IR signaling and TNBC progression is critical. The aim of this study is to understand the role of IR-A and IR-B on proliferation, metastasis and metabolism in breast cancer cells. We stably overexpressed human IR-A (IR-A OE) and IR-B (IR-B OE) in TNBC MDA-MB-231 (231) and murine c-myc/vegf overexpressing Mvt1 cells with lentiviral transduction using pLVX-IRES-puro HIV-1-based expression vectors with cDNA encoding the human IR-A,IR-B and control cDNA sequences. Native murine IR was silenced using lentiviral transduction of shRNA in the Mvt1 cells. Overexpression of IR was confirmed at a protein level by western blot, and RNA isoform expression was confirmed using real time PCR. Cell proliferation assays were performed in DMEM/10% FBS and revealed that MDA-MB-231 cells with IR-A OE cells had 15% higher proliferation rates than 231 IR-B OE cells. We then examined the IR signaling pathways by western blot in DMEM/10% FBS. No differences in phosphorylated or total ERK1/2 were observed between control, 231 IR-A OE and 231 IR-B OE cells. 231 IR-A OE cells were found to have 15-fold greater Akt phosphorylation (Ser473) than 231 control cells (p=0.0008) and 4 fold higher pAkt(Ser473) compared with 231 IR-B OE cells (p=0.0016). Further, we found that 231 IR-A OE cells had approximately 2 fold greater expression of c-myc protein compared with both 231 control (p=0.047) and 231 IR-B OE cells (p=0.026). No differences in c-myc expression were observed between 231 IRB OE and 231 control cells. In our previous studies we found that insulin stimulates c-myc expression and silencing the IR reduces c-myc expression in cancer cells. Our current studies show that IR-A, rather than IR-B is the insulin receptor isoform that regulates c-myc expression in human TNBC. Reference: (1) Belfiore et al., Endocr Relat Cancer. 2011; 18(4):R125-R147. (2) Ferguson et al., Breast Cancer Res. 2012; 14(1): R8.

A double-blind placebo-controlled clinical trial testing the effect of hyperbaric oxygen therapy on brain and cognitive outcomes of mildly cognitively impaired elderly with type 2 diabetes: Study design

INTRODUCTION

Type 2 diabetes (T2D) is a risk factor for dementia. Ischemia due to vascular pathology is hypothesized to be an underlying mechanism for this association. Hyperbaric oxygen therapy (HBOT) is a treatment in which oxygen-enriched air (up to 100%) is administered to patients in a chamber at a pressure above one atmosphere absolute. HBOT is approved for the treatment of T2D ischemic non-healing wounds. Evidence from animal studies and small clinical trials suggests that HBOT improves hypoxic/ischemic brain injuries, consequently inducing brain angiogensis, leading to cognitive improvement.

METHODS

We present the design of the first double-blind, placebo-controlled, clinical trial on brain and cognitive outcomes in elderly (n = 154) with T2D and mild cognitive impairment to compare the effects of HBOT versus sham (normal air with 1.1 ATA pressure in the first and last 5 minutes of the session). Eligible candidates are randomized with equal probability to HBOT and sham. Outcomes are assessed before and after treatment, and at 6- and 12-month follow-up. The primary cognitive outcome is global cognitive change, indexed by a composite sum of z-scores of four executive functions and four episodic memory tests. The primary neurobiological outcome is cerebral blood flow (CBF; via arterial spin labeling magnetic resonance imaging [ASL-MRI]) and cerebral glucose utilization via fluorodeoxyglucose positron emission tomography (FDG-PET). Secondary outcome measures are specific cognitive domains (executive function and episodic memory) and functional measures (Clinical Dementia Rating sum of boxes, activities of daily living). Efficacy analyses will be performed for the intent-to-treat sample.

DISCUSSION

Recent studies suggest that HBOT induces neuroplasticity and improves cognition in post-stroke and traumatic brain injury patients. However, its effect on cognition, cerebral blood flow, and brain glucose utilization in T2D patients at high dementia risk is yet to be determined. If effective, this study may provide strong evidence for the brain and cognitive benefits of HBOT in this population.

Hyperinsulinemia promotes aberrant histone acetylation in triple-negative breast cancer

Background

Hyperinsulinemia, the presence of excess insulin relative to glucose in the blood, is considered to be a poor prognostic indicator for patients with triple-negative breast cancer (TNBC). mTOR, a downstream effector of insulin, enhances mitochondrial biogenesis and activity, thereby increasing acetyl-CoA precursors. Increased acetyl-CoA can, in turn, be utilized by nuclear acetyltransferases for histone acetylation, a critical feature of genome regulation. While signaling pathways downstream of insulin have been established for sometime, the effect of insulin on chromatin remains unclear. We hypothesized that hyperinsulinemia-induced metabolic changes lead to genome-wide changes in histone acetylation in TNBC.

Results

MDA-MB-231 cells were xenografted into hyperinsulinemic and wild-type mice. Tumors in the hyperinsulinemic mice displayed elevated levels of histone acetylation compared to tumors in normal insulin conditions. We show that insulin treatment in vitro leads to global increase in chromatin-associated histone acetylation, in particular at H3K9, through the PI3K/AKT/mTOR pathway. Genome-wide analyses revealed that most promoter regions have an increase in histone acetylation upon insulin treatment. In addition, insulin induces higher levels of reactive oxygen species and DNA damage foci in cells.

Conclusions

These results demonstrate the impact of hyperinsulinemia on altered gene regulation through chromatin and the importance of targeting hyperinsulinemia-induced processes that lead to chromatin dysfunction in TNBC.

Electronic supplementary material

The online version of this article (10.1186/s13072-019-0290-9) contains supplementary material, which is available to authorized users.

Loss of Adipose Growth Hormone Receptor in Mice Enhances Local Fatty Acid Trapping and Impairs Brown Adipose Tissue Thermogenesis

Growth hormone (GH) binds to its receptor (growth hormone receptor [GHR]) to exert its pleiotropic effects on growth and metabolism. Disrupted GH/GHR actions not only fail growth but also are involved in many metabolic disorders, as shown in murine models with global or tissue-specific Ghr deficiency and clinical observations. Here we constructed an adipose-specific Ghr knockout mouse model Ad-GHRKO and studied the metabolic adaptability of the mice when stressed by high-fat diet (HFD) or cold. We found that disruption of adipose Ghr accelerated dietary obesity but protected the liver from ectopic adiposity through free fatty acid trapping. The heat-producing brown adipose tissue burning and white adipose tissue browning induced by cold were slowed in the absence of adipose Ghr but were recovered after prolonged cold acclimation. We conclude that at the expense of excessive subcutaneous fat accumulation and lower emergent cold tolerance, down-tuning adipose GHR signaling emulates a healthy obesity situation which has metabolic advantages against HFD.

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Adipose growth hormone receptor defect augments dietary obesity in mice

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Lack of adipose growth hormone receptor prevents ectopic adiposity

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Adipose growth hormone receptor defect benefits free fatty acid turnover

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Adipose growth hormone receptor facilitates thermogenic response to cold

Treatment of Diabetes in Older Adults: An Endocrine Society* Clinical Practice Guideline

OBJECTIVE

The objective is to formulate clinical practice guidelines for the treatment of diabetes in older adults.

CONCLUSIONS

Diabetes, particularly type 2, is becoming more prevalent in the general population, especially in individuals over the age of 65 years. The underlying pathophysiology of the disease in these patients is exacerbated by the direct effects of aging on metabolic regulation. Similarly, aging effects interact with diabetes to accelerate the progression of many common diabetes complications. Each section in this guideline covers all aspects of the etiology and available evidence, primarily from controlled trials, on therapeutic options and outcomes in this population. The goal is to give guidance to practicing health care providers that will benefit patients with diabetes (both type 1 and type 2), paying particular attention to avoiding unnecessary and/or harmful adverse effects.

Insulin-like growth factor receptor signaling in breast tumor epithelium protects cells from endoplasmic reticulum stress and regulates the tumor microenvironment

BACKGROUND

Early analyses of human breast cancer identified high expression of the insulin-like growth factor type 1 receptor (IGF-1R) correlated with hormone receptor positive breast cancer and associated with a favorable prognosis, whereas low expression of IGF-1R correlated with triple negative breast cancer (TNBC). We previously demonstrated that the IGF-1R acts as a tumor and metastasis suppressor in the Wnt1 mouse model of TNBC. The mechanisms for how reduced IGF-1R contributes to TNBC phenotypes is unknown.

METHODS

We analyzed the METABRIC dataset to further stratify IGF-1R expression with patient survival and specific parameters of TNBC. To investigate molecular events associated with the loss of IGF-1R function in breast tumor cells, we inhibited IGF-1R in human cell lines using an IGF-1R blocking antibody and analyzed MMTV-Wnt1-mediated mouse tumors with reduced IGF-1R function through expression of a dominant-negative transgene.

RESULTS

Our analysis of the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) dataset revealed association between low IGF-1R and reduced overall patient survival. IGF-1R expression was inversely correlated with patient survival even within hormone receptor-positive breast cancers, indicating reduced overall patient survival with low IGF-1R was not due simply to low IGF-1R expression within TNBCs. Inhibiting IGF-1R in either mouse or human tumor epithelial cells increased reactive oxygen species (ROS) production and activation of the endoplasmic reticulum stress response. IGF-1R inhibition in tumor epithelial cells elevated interleukin (IL)-6 and C-C motif chemokine ligand 2 (CCL2) expression, which was reversed by ROS scavenging. Moreover, the Wnt1/dnIGF-1R primary tumors displayed a tumor-promoting immune phenotype. The increased CCL2 promoted an influx of CD11b⁺ monocytes into the primary tumor that also had increased matrix metalloproteinase (MMP)-2, MMP-3, and MMP-9 expression. Increased MMP activity in the tumor stroma was associated with enhanced matrix remodeling and collagen deposition. Further analysis of the METABRIC dataset revealed an increase in IL-6, CCL2, and MMP-9 expression in patients with low IGF-1R, consistent with our mouse tumor model and data in human breast cancer cell lines.

CONCLUSIONS

Our data support the hypothesis that reduction of IGF-1R function increases cellular stress and cytokine production to promote an aggressive tumor microenvironment through infiltration of immune cells and matrix remodeling.

Diabetes, Obesity, and Breast Cancer

The rates of obesity and diabetes are increasing worldwide, whereas the age of onset for both obesity and diabetes are decreasing steadily. Obesity and diabetes are associated with multiple factors that contribute to the increased risk of a number of different cancers, including breast cancer. These factors are hyperinsulinemia, elevated IGFs, hyperglycemia, dyslipidemia, adipokines, inflammatory cytokines, and the gut microbiome. In this review, we discuss the current understanding of the complex signaling pathways underlying these multiple factors involved in the obesity/diabetes-breast cancer link, with a focus particularly on the roles of the insulin/IGF system and dyslipidemia in preclinical breast cancer models. We review some of the therapeutic strategies to target these metabolic derangements in cancer. Future research directions and potential therapeutic strategies are also discussed.

World leaders describe the latest in IGF research

One of the most pervasive systems in biology is the insulinlike growth factor (IGF) system of ligands, binding proteins and receptors. Since their discovery in the 1950s, the interest in the IGFs has motivated biologists, biochemists, molecular geneticists, evolutionists, physiologist, pharmacologists and pharmaceutical and biotech companies. The IGF system plays important roles in normal physiology but in addition has been shown to be intimately involved in a wide array of disease processes including growth retardation, diabetes, cancer and neurological disorders, to name but a few. Thus, there has been interest in stimulating the IGF system on the one hand and inhibiting the system on the other hand. The current issue has been created on a range of topics that cover some of the recent developments in the field to give the reader a taste of this exciting and relevant biological system.

Hyperinsulinemia Promotes Esophageal Cancer Development in a Surgically-Induced Duodeno-Esophageal Reflux Murine Model

Hyperinsulinemia could have a role in the growing incidence of esophageal adenocarcinoma (EAC) and its pre-cancerous lesion, Barrett's Esophagus, a possible consequence of Gastro-Esophageal Reflux Disease. Obesity is known to mediate esophageal carcinogenesis through different mechanisms including insulin-resistance leading to hyperinsulinemia, which may mediate cancer progression via the insulin/insulin-like growth factor axis. We used the hyperinsulinemic non-obese FVB/N (Friend leukemia virus B strain) MKR (muscle (M)-IGF1R-lysine (K)-arginine (R) mouse model to evaluate the exclusive role of hyperinsulinemia in the pathogenesis of EAC related to duodeno-esophageal reflux. FVB/N wild-type (WT) and MKR mice underwent jejunum-esophageal anastomosis side-to end with the exclusion of the stomach. Thirty weeks after surgery, the esophagus was processed for histological, immunological and insulin/Insulin-like growth factor 1 (IGF1) signal transduction analyses. Most of the WT mice (63.1%) developed dysplasia, whereas most of the MKR mice (74.3%) developed squamous cell and adenosquamous carcinomas, both expressing Human Epidermal growth factor receptor 2 (HER2). Hyperinsulinemia significantly increased esophageal cancer incidence in the presence of duodenal-reflux. Insulin receptor (IR) and IGF1 receptor (IGF1R) were overexpressed in the hyperinsulinemic condition. IGF1R, through ERK1/2 mitogenic pattern activation, seems to be involved in cancer onset. Hyperinsulinemia-induced IGF1R and HER2 up-regulation could also increase the possibility of forming of IGF1R/HER2 heterodimers to support cell growth/proliferation/progression in esophageal carcinogenesis.

New melanocortin-like peptide of E. coli can suppress inflammation via the mammalian melanocortin-1 receptor (MC1R): possible endocrine-like function for microbes of the gut

E. coli releases a 33 amino acid peptide melanocortin-like peptide of E. coli (MECO-1) that is identical to the C-terminus of the E. coli elongation factor-G (EF-G) and has interesting similarities to two prominent mammalian melanocortin hormones, alpha-melanocyte-stimulating hormone (alpha-MSH) and adrenocorticotropin (ACTH). Note that MECO-1 lacks HFRW, the common pharmacophore of the known mammalian melanocortin peptides. MECO-1 and the two hormones were equally effective in severely blunting release of cytokines (HMGB1 and TNF) from macrophage-like cells in response to (i) endotoxin (lipopolysaccharide) or (ii) pro-inflammatory cytokine HMGB-1. The in vitro anti-inflammatoty effects of MECO-1 and of alpha-MSH were abrogated by (i) antibody against melanocortin-1 receptor (MC1R) and by (ii) agouti, an endogenous inverse agonist of MC1R. In vivo MECO-1 was even more potent than alpha-MSH in rescuing mice from death due to (i) lethal doses of LPS endotoxin or (ii) cecal ligation and puncture, models of sterile and infectious sepsis, respectively.

OP449 inhibits breast cancer growth without adverse metabolic effects

Hyperinsulinemia is associated with a decrease in breast cancer recurrence-free survival and overall survival. Inhibition of insulin receptor signaling is associated with glycemic dysregulation. SET is a direct modulator of PP2A, which negatively regulates the PI3K/AKT/mTOR pathway. OP449, a SET inhibitor, decreases AKT/mTOR activation. The effects of OP449 treatment on breast cancer growth in the setting of pre-diabetes, and its metabolic implications are currently unknown. We found that the volumes and weights of human MDA-MB-231 breast cancer xenografts were greater in hyperinsulinemic mice compared with controls (P < 0.05), and IR phosphorylation was 4.5-fold higher in these mice (P < 0.05). Human and murine breast cancer tumors treated with OP449 were 47% and 39% smaller than controls (P < 0.05, for both, respectively). AKT and S6RP phosphorylation were 82% and 34% lower in OP449-treated tumors compared with controls (P < 0.05, P = 0.06, respectively). AKT and S6RP phosphorylation in response to insulin was 30% and 12% lower in cells, pre-treated with OP449, compared with control cells (P < 0.01, P < 0.05, respectively). However, even with decreased AKT/mTOR activation, body weights and composition, blood glucose and plasma insulin, glucose tolerance, serum triglyceride and cholesterol levels were similar between OP449-treated mice and controls. Xenografts and liver tissue from OP449-treated mice showed a 64% and 70% reduction in STAT5 activation, compared with controls (P < 0.01 and P = 0.06, respectively). Our data support an anti-neoplastic effect of OP449 on human breast cancer cells in vitro and in xenografts in the setting of hyperinsulinemia. OP449 led to the inhibition of AKT/mTOR signaling, albeit, not leading to metabolic derangements.

Hexarelin, a Growth Hormone Secretagogue, Improves Lipid Metabolic Aberrations in Nonobese Insulin-Resistant Male MKR Mice

Despite the occurrence of dyslipidemia and its contribution to the development of insulin resistance in obese subjects, a growing number of studies have described abnormal lipid profiles among leaner persons. For example, individuals with an abnormal paucity or distribution of fat (lipodystrophy) develop severe insulin resistance, dyslipidemia, and hepatic steatosis. Deranged adipocyte metabolism and differentiation contribute to ectopic fat deposition and consequent development of insulin resistance. Growth hormone (GH) therapy has been shown to correct body composition abnormalities in some lipodystrophy patients. However, little is known about the effects of GH-releasing peptides in this regard. Hexarelin, a GH secretagogue, has recently been shown to have beneficial effects on fat metabolism via the CD36 receptor. In this study, the effects of twice daily intraperitoneal injections of hexarelin (200 μg/kg body weight) were examined in nonobese insulin-resistant MKR mice and corresponding wild-type FVB mice for 12 days. Hexarelin treatment significantly improved glucose and insulin intolerance and decreased plasma and liver triglycerides in MKR mice. These beneficial metabolic effects could be due to the improved lipid metabolism and enhanced adipocyte differentiation of white adipose tissue with hexarelin treatment. Interestingly, although food intake of hexarelin-treated MKR mice was significantly increased, this did not change total body weight. Moreover, hexarelin treatment corrected the abnormal body composition of MKR mice, as demonstrated by a decrease in fat mass and an increase in lean mass. Our results suggest a possible application of hexarelin in treatment of lipid disorders associated with the metabolic syndrome.

Long-term treatment with the ghrelin receptor antagonist [d-Lys3]-GHRP-6 does not improve glucose homeostasis in nonobese diabetic MKR mice

Long-term treatment with the ghrelin receptor antagonist [d-Lys3]-GHRP-6 does not improve glucose homeostasis in nonobese diabetic MKR mice. Am J Physiol Regul Integr Comp Physiol 314: R71-R83, 2018. First published September 13, 2017; doi: 10.1152/ajpregu.00157.2017 .-Ghrelin secretion has been associated with increased caloric intake and adiposity. The expressions of ghrelin and its receptor (GHS-R1a) in the pancreas has raised the interest about the role of ghrelin in glucose homeostasis. Most of the studies showed that ghrelin promoted hyperglycemia and inhibited insulin secretion. This raised the interest in using GHS-R1a antagonists as therapeutic targets for type 2 diabetes. Available data of GHS-R antagonists are on a short-term basis. Moreover, the complexity of GHS-R1a signaling makes it difficult to understand the mechanism of action of GHS-R1a antagonists. This study examined the possible effects of long-term treatment with a GHS-R1a antagonist, [d-Lys3]-growth hormone-releasing peptide (GHRP)-6, on glucose homeostasis, food intake, and indirect calorimetric parameters in nonobese diabetic MKR mice. Our results showed that [d-Lys3]-GHRP-6 (200 nmol/mouse) reduced pulsatile growth hormone secretion and body fat mass as expected but worsened glucose and insulin intolerances and increased cumulative food intake unexpectedly. In addition, a significant increase in blood glucose and decreases in plasma insulin and C-peptide levels were observed in MKR mice following long-term [d-Lys3]-GHRP-6 treatment, suggesting a direct inhibition of insulin secretion. Immunofluorescence staining of pancreatic islets showed a proportional increase in somatostatin-positive cells and a decrease in insulin-positive cells in [d-Lys3]-GHRP-6-treated mice. Furthermore, [d-Lys3]-GHRP-6 stimulated food intake on long-term treatment via reduction of proopiomelanocortin gene expression and antagonized GH secretion via reduced growth hormone-releasing hormone gene expression in hypothalamus. These results demonstrate that [d-Lys3]-GHRP-6 is not completely opposite to ghrelin and may not be a treatment option for type 2 diabetes.

Abstract 1004: LDLR knockdown reduces the growth of Her2 overexpressing breast cancer in mouse models of hyperlipidemia

Women with higher circulating low density lipoprotein (LDL) cholesterol levels are more likely to have advanced HER2 positive breast cancers. The LDL receptor (LDLR) is the main receptor for cholesterol uptake into cells from circulating LDL and its expression is higher in HER2 positive breast cancers than other subtypes. The aim of our study was to understand the importance of the LDLR in the progression of HER2 positive breast cancer growth in the setting of hyperlipidemia. To study the role of hyperlipidemia in HER2 cancer progression, we used two mouse models with elevated LDL cholesterol: Apolipoprotein E knockout (ApoE-/-), and LDLR knockout (LDLR-/-) mice on an FVB/n background. ApoE-/-, LDLR-/- and control (WT) mice were placed on a western diet at 8-10 weeks of age. After 2 weeks on the diet, serum cholesterol concentrations were measured and demonstrated significantly higher cholesterol levels in the ApoE-/- and LDLR-/- mice compared with WT mice (WT: 208±19mg/dL; LDLR-/-: 488±37mg/dL; ApoE-/- 660±39mg/dL). We used the MCNeuA (MMTV-Neu derived) breast cancer cells to study the effect of hyperlipidemia on Her2/Neu positive breast cancer in this model, as the MCNeuA cells were found to have high levels of LDLR protein expression compared with other murine breast cancer cell lines. To study the importance of the LDLR in mediating the effects of hyperlipidemia, we knocked down the LDLR in the MCNeuA cells using shRNA, and selected two cell clones with successful gene knockdown confirmed by RNA and protein analysis. ApoE-/-, LDLR-/- and WT mice on the western diet were injected into the 4th mammary fat pad with 2 x 106 MCNeuA (MMTV-Neu derived) control shRNA or MCNeuA LDLR knockdown clone 1 or clone 2 cells (n=6-10 mice per group). Tumor growth was measured for 30 days. Control shRNA tumors in both hyperlipidemic mouse genotypes grew more rapidly than in the WT mice. 30 days after injection the control tumor volumes were: WT 514±66.5mm3; LDLR-/- 767±78.2mm3; ApoE-/- 1189±94mm3. The LDLR knockdown clones 1 and 2 had a reduction of tumor volume of 11% and 30% in the WT mice, 28% and 62% in LDLR-/- mice, and 26% and 53% in the ApoE-/- mice, respectively compared with the control shRNA cells. Western blot analysis of tumor protein lysates showed an increase in p19 cleaved caspase 3 in the tumors with LDLR knockdown, compared with the control cells. In vitro studies demonstrated a decrease in survival of MCNeuA cells with LDLR knockdown in serum starved conditions, and an increase in caspase 3 cleavage. These data demonstrate that hyperlipidemia promotes the growth of Her2/Neu overexpressing breast cancer cells and the LDLR plays an important role in protecting Her2 / Neu tumors from apoptosis. Therefore, targeting cholesterol uptake and metabolism may be an important strategy for women with HER2 positive breast cancers.

Citation Format: Emily J. Gallagher, Brian A. Neel, Zara Zelenko, Irini Markella Antoniou, Nathan Kase, Derek LeRoith. LDLR knockdown reduces the growth of Her2 overexpressing breast cancer in mouse models of hyperlipidemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1004. doi:10.1158/1538-7445.AM2017-1004

Activating Transcription Factor-5 Knockdown Reduces Aggressiveness of Mammary Tumor Cells and Attenuates Mammary Tumor Growth

Activating transcription factor-5 (ATF5) is an anti-apoptotic factor and has been implicated in enhancing the survival of cancer cells under stress and in regulating the autophagy process. Targeting ATF5 in anticancer therapy may be particularly attractive because of its differential role in cancer cells than in non-transformed cells, thus allowing specificity of the treatment. Using the delivery of short hairpin RNA vectors into the Mvt1 and Met1 cell lines, we tested the role of ATF5 in the development of mammary tumors in vivo and in regulating proliferation and migration of these cells in vitro. In this study, we demonstrate that knockdown of ATF5 (ATF5-KD) in both cell lines results in a decreased tumor volume and weight, as well as in a reduced proliferation rate and migratory potential of the cells. In addition, ATF5-KD led to an increased autophagy flux and a shift in the sub-populations comprising Mvt1 cells from the aggressive CD24-positive cells toward less aggressive CD24-negative cells. Taken together, these findings suggest that ATF5 plays an important role in enhancing mammary tumor cells overall aggressiveness and in promoting mammary tumor growth and emphasize the possible benefit of anti-ATF5 therapy in breast cancer patients, particularly, against tumors characterized with the positive expression of cell surface CD24.

Type 2 Diabetes Mellitus and Cancer: The Role of Pharmacotherapy

Purpose Type 2 diabetes mellitus (T2DM) is becoming increasingly prevalent worldwide. Epidemiologic data suggest that T2DM is associated with an increased incidence and mortality from many cancers. The purpose of this review is to discuss the links between diabetes and cancer, the effects of various antidiabetic medications on cancer incidence and mortality, and the effects of anticancer therapies on diabetes. Design This study is a review of preclinical and clinical data regarding the effects of antidiabetic medications on cancer incidence and mortality and the effects of anticancer therapies on glucose homeostasis. Results T2DM is associated with an increased risk and greater mortality from many cancer types. Metformin use has been associated with a decrease in cancer incidence and mortality, and there are many ongoing randomized trials investigating the effects of metformin on cancer-related outcomes. However, data regarding the association of other antidiabetes medications with cancer incidence and mortality are conflicting. Glucocorticoids, hormone-based therapies, inhibitors that target the phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin pathway, and insulin-like growth factor 1 receptor-targeted therapy have been associated with high rates of hyperglycemia. These agents mediate their deleterious metabolic effects by reducing insulin secretion and increasing insulin resistance in peripheral tissues. Conclusion Studies must be performed to optimize cancer screening strategies in individuals with T2DM. A greater understanding of the mechanisms that link diabetes and cancer are needed to identify targets for therapy in individuals with diabetes who develop cancer. Data from clinical studies are needed to further elucidate the effects of antidiabetic medications on cancer incidence and progression. As several anticancer therapies alter glucose homeostasis, physicians need to be aware of these potential effects. Careful patient screening and monitoring during treatment with these agents is necessary.

Metabolic syndrome and pre-diabetes contribute to racial disparities in breast cancer outcomes: hypothesis and proposed pathways

BACKGROUND

Women with obesity and type 2 diabetes (T2D) are at greater risk of dying from breast cancer than women without these conditions. Obesity and T2D are associated with insulin resistance and endogenous hyperinsulinemia and are more common in Black women. There is increasing disparity in breast cancer mortality between Black and White women in the USA. We hypothesize that insulin resistance and endogenous hyperinsulinemia in Black women with breast cancer contribute to their greater breast cancer mortality and are associated with increased insulin receptor signalling in tumours.

METHODS

We will recruit 350 Black women and 936 White women with newly diagnosed breast cancer. We will determine the presence or absence of the metabolic syndrome/pre-diabetes and insulin resistance by measuring body mass index, waist circumference, lipids, blood pressure, glucose, insulin-like growth factor binding protein 1 and insulin. Breast cancer prognosis will be determined by a Nottingham Prognostic Index (NPI), with poor prognosis being defined as NPI >4.4. Tumour insulin receptor signalling will be determined by immunohistochemistry. Insulin receptor subtype expression will be measured using Nanostring. Analysis of these factors will determine whether endogenous hyperinsulinemia is associated with a worse prognosis in Black women than White women and increased tumour insulin receptor signalling.

CONCLUSIONS

The results of this study will determine if the metabolic syndrome and pre-diabetes contribute to racial disparities in breast cancer mortality. It may provide the basis for targeting systemic insulin resistance and/or tumour insulin receptor signalling to reduce racial disparities in breast cancer mortality. Copyright © 2016 John Wiley & Sons, Ltd.

EMT reversal in human cancer cells after IR knockdown in hyperinsulinemic mice

Type 2 diabetes (T2D) is associated with increased cancer risk and cancer-related mortality. Data herein show that we generated an immunodeficient hyperinsulinemic mouse by crossing the Rag1(-/-) mice, which have no mature B or T lymphocytes, with the MKR mouse model of T2D to generate the Rag1(-/-) (Rag/WT) and Rag1(-/-)/MKR(+/+) (Rag/MKR) mice. The female Rag/MKR mice are insulin resistant and have significantly higher nonfasting plasma insulin levels compared with the Rag/WT controls. Therefore, we used these Rag/MKR mice to investigate the role of endogenous hyperinsulinemia on human cancer progression. In this study, we show that hyperinsulinemia in the Rag/MKR mice increases the expression of mesenchymal transcription factors, TWIST1 and ZEB1, and increases the expression of the angiogenesis marker, vascular endothelial growth factor A (VEGFA). We also show that silencing the insulin receptor (IR) in the human LCC6 cancer cells leads to decreased tumor growth and metastases, suppression of mesenchymal markers vimentin, SLUG, TWIST1 and ZEB1, suppression of angiogenesis markers, VEGFA and VEGFD, and re-expression of the epithelial marker, E-cadherin. The data in this paper demonstrate that IR knockdown in primary tumors partially reverses the growth-promoting effects of hyperinsulinemia as well as highlighting the importance of the insulin receptor signaling pathway in cancer progression, and more specifically in epithelial-mesenchymal transition.