Diabetes as a prognostic factor in HER-2 positive breast cancer patients treated with targeted therapy

Metformin and HER2-positive breast cancer: Mechanisms and therapeutic implications

Due to the strong association between diabetes and cancer incidents, several anti-diabetic drugs, including metformin, have been examined for their anticancer activity. Metformin is a biguanide antihyperglycemic agent used as a first-line drug for type II diabetes mellitus. It exhibits anticancer activity by impacting different molecular pathways, such as AMP-inducible protein kinase (AMPK)-dependent and AMPK-independent pathways. Additionally, Metformin indirectly inhibits IGF-1R signaling, which is highly activated in breast malignancy. On the other hand, breast cancer is one of the major causes of cancer-related morbidity and mortality worldwide, where the human epidermal growth factor receptor-positive (HER2-positive) subtype is one of the most aggressive ones with a high rate of lymph node metastasis. In this review, we summarize the association between diabetes and human cancer, listing recent evidence of metformin's anticancer activity. A special focus is dedicated to HER2-positive breast cancer with regards to the interaction between HER2 and IGF-1R. Then, we discuss combination therapy strategies of metformin and other anti-diabetic drugs in HER2-positive breast cancer.

Epigenetic regulation of Neuregulin 1 promotes breast cancer progression associated to hyperglycemia

Hyperglycemia is a risk factor for breast cancer-related morbidity and mortality. Hyperglycemia induces Neuregulin 1 (Nrg1) overexpression in breast cancer, which subsequently promotes tumor progression. However, molecular mechanisms underlying hyperglycemia-induced Nrg1 overexpression remain poorly understood. Here, we show that hyperglycemia causes active histone modifications at the Nrg1 enhancer, forming enhanceosome complexes where recombination signal binding protein for immunoglobulin kappa J region (RBPJ), E1A binding protein p300 (P300), and SET domain containing 1 A (SETD1A) are recruited to upregulate Nrg1 expression. Deletions in RBPJ-binding sites causes hyperglycemia-controlled Nrg1 levels to be downregulated, resulting in decreased tumor growth in vitro and in vivo. Mice with modest-temporary hyperglycemia, induced by low-dose short-exposure streptozotocin, display accelerated tumor growth and lapatinib resistance, whereas combining lapatinib with N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S42 phenylglycine t-butyl ester (DAPT) ameliorates tumor growth under these modest hyperglycemic conditions by inhibiting NOTCH and EGFR superfamilies. NOTCH activity is correlated with NRG1 levels, and high NRG1 levels predicts poor outcomes, particularly in HER2-positive breast cancer patients. Our findings highlight the hyperglycemia-linked epigenetic modulation of NRG1 as a potential therapeutic strategy for treating breast cancer patients with diabetes.

Cost-Effectiveness Analysis of Pertuzumab Plus Trastuzumab and Docetaxel Compared With Trastuzumab and Docetaxel in the Adjuvant Treatment of Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer in Colombia

OBJECTIVES

The addition of pertuzumab to the scheme of docetaxel plus trastuzumab (TH) in patients with metastatic breast cancer with overexpression of human epidermal growth factor receptor 2 increases survival. Nevertheless, this addition could represent a high cost for the health system of a middle-income country such as Colombia. Therefore, it is necessary to evaluate the efficiency of the pertuzumab plus TH (PTH) scheme in comparison with TH.

METHODS

A partitioned survival model-based cost-utility analysis was performed. Progression-free survival and overall survival curves for each scheme were obtained from the CLEOPATRA study. The time horizon was 30 years with a discount rate of 5% for costs and quality-adjusted life-years. Total direct costs were calculated using national tariffs. Utilities were obtained from external sources. Model uncertainty was evaluated by deterministic and probabilistic sensitivity analysis. A willingness to pay value of 5180 US dollars was used.

RESULTS

The discounted total average costs of TH and PTH were $24 109 and $60 846, respectively. These regimens' average life-years were 5.78 and 8.38, and their quality-adjusted life-years were 3.28 and 4.51, respectively. The incremental cost-effectiveness ratio was $29 867. One-way sensitivity analysis showed that the cost of pertuzumab was the variable that explained the uncertainty in the model. The probability that PTH is cost-effective in the probabilistic sensitivity analysis is 0.0724.

CONCLUSIONS

The addition of pertuzumab to the TH regimen in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer has a low probability of being cost-effective from the payer's perspective in the Colombian health system.

Diabetes and Cancer - optimising glycaemic control

Diabetes and cancer are both common and increasingly prevalent conditions, but emerging epidemiological evidence confirms that the risk of developing a number of common cancers is increased in those with type 2 diabetes. The risk of cancer in type 1 diabetes is less clearly defined, and therefore this review will focus on type 2 diabetes. Emerging evidence also supports an influence of diabetes on outcomes of cancer treatment. However, this relationship is bi-directional, with cancer and its treatment impacting on glucose control, whilst there is also emerging evidence that diabetes care can deteriorate after a cancer diagnosis (summarised in Figure 1). Despite these clear links there is a lack of evidence to guide clinicians in how to manage patients with diabetes during their cancer treatment. Although recent UK guidelines have started to address this, with the development of guidance for the management of hyperglycaemia in cancer, there is a clear need for wider guidance on the management of multi-morbidity during cancer, including diabetes and obesity, to incorporate nutritional management We have therefore undertaken a narrative review of the evidence of links between type 2 diabetes and cancer incidence and outcomes, and discuss the challenges to diabetes care during cancer treatment. This article is protected by copyright. All rights reserved.

Decreased expression of ErbB2 on left ventricular epicardial cells in patients with diabetes mellitus

We investigated the cell surface expression of ErbB receptors on left ventricular (LV) epicardial endothelial cells and CD105⁺ cells obtained from cardiac biopsies of patients undergoing coronary artery bypass grafting surgery (CABG). Endothelial cells and CD105⁺ non-endothelial cells were freshly isolated from LV epicardial biopsies obtained from 15 subjects with diabetes mellitus (DM) and 8 controls. The expression of ErbB receptors was examined using flow cytometry. We found that diabetes mellitus (DM) and high levels of hemoglobin A1C are associated with reduced expression of ErbB2. To determine if the expression of ErbB2 receptors is regulated by glucose levels, we examined the effect of high Glucose in human microvascular endothelial cells (HMEC-1) and CD105⁺ non-endothelial cells, using a novel flow cytometric approach to simultaneously determine the total level, cell surface expression, and phosphorylation of ErbB2. Incubation of cells in the presence of 25 mM d-glucose resulted in decreased cell surface but not total levels of ErbB2. The level of ErbB2 at the cell surface is controlled by disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) that is expressed on LV epicardial cells. Inhibition of ADAM10 prevented the high glucose-dependent decrease in the cell surface expression of ErbB2. We suggest that high Glucose depresses ErbB receptor signaling in endothelial cells and cardiac progenitor cells via the promotion of ADAM10-dependent cleavage of ErbB2 at the cell surface, thus contributing to vascular dysfunction and adverse remodeling seen in diabetic patients.

Treatment outcomes among human epidermal growth factor receptor 2 positive breast cancer patients: A systematic review

BACKGROUND

The incidence of human epidermal growth factor receptor 2 (HER 2) positive breast cancers is rapidly rising worldwide. Although there have been many studies on HER 2 breast cancer treatment and management in recent years, there is a lack of comprehensive reports on the treatment outcomes and disparities within the available literature. Hence, this review aimed to determine the treatment outcomes and their associated factors among patients with HER2-positive breast cancer.

METHODS

A computer-based systematic literature search was conducted using PubMed, EMBASE, and Google scholar databases of articles published from 2000 to 2020. The following key terms (HER 2 positive breast cancer, predictor, determinant, associated factor) and Medical Subject Headings (MeSH) terms (breast neoplasms, treatment outcome, and risk factors) were used to search the English language published articles.

RESULTS

In most studies, trastuzumab was the most commonly used treatment regimen used in combination with chemotherapeutic agents. Generally, most of the studies (15 studies) showed that the overall survival outcome was relatively higher after treatment among HER2 positive breast cancer patients. Nonetheless, two studies showed that the absence of significant change in the overall survival despite adequate treatment was given to the study participants. In addition, three studies demonstrated a partial response after treating HER2-positive breast cancer patients.

CONCLUSION

Generally, the overall survival outcome was relatively higher after treatment among HER2 positive breast cancer patients. The addition of trastuzumab in most of the studies has shown improvement in the overall survival and the disease-free survival rate of the study patients.

Metabolic Syndrome and Breast Cancer: Prevalence, Treatment Response, and Prognosis

Metabolic syndrome is a type of multifactorial metabolic disease with the presence of at least three factors: obesity, diabetes mellitus, low high-density lipoprotein, hypertriglyceridemia, and hypertension. Recent studies have shown that metabolic syndrome and its related components exert a significant impact on the initiation, progression, treatment response, and prognosis of breast cancer. Metabolic abnormalities not only increase the disease risk and aggravate tumor progression but also lead to unfavorable treatment responses and more treatment side effects. Moreover, biochemical reactions caused by the imbalance of these metabolic components affect both the host general state and organ-specific tumor microenvironment, resulting in increased rates of recurrence and mortality. Therefore, this review discusses the recent advances in the association of metabolic syndrome and breast cancer, providing potential novel therapeutic targets and intervention strategies to improve breast cancer outcome.