Maternal obesity increases offspring's mammary cancer recurrence and impairs tumor immune response

Maternal high-fat diet increases the susceptibility of offspring to colorectal cancer via the activation of intestinal inflammation

A high-fat diet plays a key role in the pathogenesis of colorectal cancer, and this effect on the gut can also occur in the offspring of mothers with a high-fat diet. In this review, we discuss the role of a high-fat diet in the pathogenesis of colorectal cancer and summarize the effects of a maternal high-fat diet on the activation of inflammation and development of colorectal cancer in offspring. Studies have found that a maternal high-fat diet primarily induces an inflammatory response in the colorectal tissue of both the mother herself and the offspring during pregnancy. This leads to the accumulation of inflammatory cells in the colorectal tissue and the release of inflammatory cytokines, which further activate the NF-κb and related inflammatory signaling pathways. Research suggests that high levels of lipids and inflammatory factors from mothers with a high-fat diet are passed to the offspring through the transplacental route, which induces colorectal inflammation, impairs the intestinal microecological structure and the intestinal barrier, and interferes with intestinal development in the offspring. This in turn activates the NF-κb and related signaling pathways, which further aggravates intestinal inflammation. This process of continuous inflammatory stimulation and repair may promote the uncontrolled proliferation of colorectal mucosal cells in the offspring, thus increasing their susceptibility to colorectal cancer.

A review of the impact of energy balance on triple-negative breast cancer

Cancer cells cannot proliferate without sufficient energy to generate biomass for rapid cell division, as well as to fuel their functions at baseline. For this reason, many recent observational and interventional studies have focused on increasing energy expenditure and/or reducing energy intake during and after cancer treatment. The impact of variance in diet composition and in exercise on cancer outcomes has been detailed extensively elsewhere and is not the primary focus of this review. Instead, in this translational, narrative review we examine studies of how energy balance impacts anticancer immune activation and outcomes in triple-negative breast cancer (TNBC). We discuss preclinical, clinical observational, and the few clinical interventional studies on energy balance in TNBC. We advocate for the implementation of clinical studies to examine how optimizing energy balance-through changes in diet and/or exercise-may optimize the response to immunotherapy in people with TNBC. It is our conviction that by taking a holistic approach that includes energy balance as a key factor to be considered during and after treatment, cancer care may be optimized, and the detrimental effects of cancer treatment and recovery on overall health may be minimized.

Functional biotransformation of phytoestrogens by gut microbiota with impact on cancer treatment

The human gut is a host for trillions of microorganisms, divided into more than 3000 heterogeneous species, which is called the gut microbiota. The gut microbiota composition can be altered by many different endogenous and exogenous factors, especially diet and nutrition. A diet rich in phytoestrogens, a variable group of chemical compounds similar to 17-β-estradiol (E2), the essential female steroid sex hormone is potent to change the composition of gut microbiota. However, the metabolism of phytoestrogens also highly depends on the action of enzymes produced by gut microbiota. Novel studies have shown that phytoestrogens could play an important role in the treatment of different types of cancers, such as breast cancer in women, due to their potential to decrease estrogen levels. This review aims to summarize recent findings about the lively dialogue between phytoestrogens and the gut microbiota and to address their possible future application, especially in treating patients with diagnosed breast cancer. A potential therapeutic approach for the prevention and improving outcomes in breast cancer patients could be based on targeted probiotic supplementation with the use of soy phytoestrogens. A positive effect of probiotics on the outcome and survival of patients with breast cancer has been established. However, more in vivo scientific studies are needed to pave the way for the use of probiotics and phytoestrogens in the clinical practice of breast cancer treatment.

Maternal obesity and resistance to breast cancer treatments among offspring: Link to gut dysbiosis

BACKGROUND

About 50 000 new cases of cancer in the United States are attributed to obesity. The adverse effects of obesity on breast cancer may be most profound when affecting the early development; that is, in the womb of a pregnant obese mother. Maternal obesity has several long-lasting adverse health effects on the offspring, including increasing offspring's breast cancer risk and mortality. Gut microbiota is a player in obesity as well as may impact breast carcinogenesis. Gut microbiota is established early in life and the microbial composition of an infant's gut becomes permanently dysregulated because of maternal obesity. Metabolites from the microbiota, especially short chain fatty acids (SCFAs), play a critical role in mediating the effect of gut bacteria on multiple biological functions, such as immune system, including tumor immune responses.

RECENT FINDINGS

Maternal obesity can pre-program daughter's breast cancer to be more aggressive, less responsive to treatments and consequently more likely to cause breast cancer related death. Maternal obesity may also induce poor response to immune checkpoint inhibitor (ICB) therapy through increased abundance of inflammation associated microbiome and decreased abundance of bacteria that are linked to production of SCFAs. Dietary interventions that increase the abundance of bacteria producing SCFAs potentially reverses offspring's resistance to breast cancer therapy.

CONCLUSION

Since immunotherapies have emerged as highly effective treatments for many cancers, albeit there is an urgent need to enlarge the patient population who will be responsive to these treatments. One of the factors which may cause ICB refractoriness could be maternal obesity, based on its effects on the microbiota markers of ICB therapy response among the offspring. Since about 40% of children are born to obese mothers in the Western societies, it is important to determine if maternal obesity impairs offspring's response to cancer immunotherapies.

Maternal obesity and the impact of associated early-life inflammation on long-term health of offspring

The prevalence of obesity is increasingly common in the United States, with ~25% of women of reproductive age being overweight or obese. Metaflammation, a chronic low grade inflammatory state caused by altered metabolism, is often present in pregnancies complicated by obesity. As a result, the fetuses of mothers who are obese are exposed to an in-utero environment that has altered nutrients and cytokines. Notably, both human and preclinical studies have shown that children born to mothers with obesity have higher risks of developing chronic illnesses affecting various organ systems. In this review, the authors sought to present the role of cytokines and inflammation during healthy pregnancy and determine how maternal obesity changes the inflammatory landscape of the mother, leading to fetal reprogramming. Next, the negative long-term impact on offspring’s health in numerous disease contexts, including offspring’s risk of developing neuropsychiatric disorders (autism, attention deficit and hyperactive disorder), metabolic diseases (obesity, type 2 diabetes), atopy, and malignancies will be discussed along with the potential of altered immune/inflammatory status in offspring as a contributor of these diseases. Finally, the authors will list critical knowledge gaps in the field of developmental programming of health and diseases in the context of offspring of mothers with obesity, particularly the understudied role of hematopoietic stem and progenitor cells.

Experimental models of endocrine responsive breast cancer: strengths, limitations, and use

Breast cancers characterized by expression of estrogen receptor-alpha (ER; ESR1) represent approximately 70% of all new cases and comprise the largest molecular subtype of this disease. Despite this high prevalence, the number of adequate experimental models of ER+ breast cancer is relatively limited. Nonetheless, these models have proved very useful in advancing understanding of how cells respond to and resist endocrine therapies, and how the ER acts as a transcription factor to regulate cell fate signaling. We discuss the primary experimental models of ER+ breast cancer including 2D and 3D cultures of established cell lines, cell line- and patient-derived xenografts, and chemically induced rodent models, with a consideration of their respective general strengths and limitations. What can and cannot be learned easily from these models is also discussed, and some observations on how these models may be used more effectively are provided. Overall, despite their limitations, the panel of models currently available has enabled major advances in the field, and these models remain central to the ability to study mechanisms of therapy action and resistance and for hypothesis testing that would otherwise be intractable or unethical in human subjects.

Maternal fish oil consumption has a negative impact on mammary gland tumorigenesis in C3(1) Tag mice offspring

PURPOSE

Omega-3 fatty acids have been shown to reduce the incidence and slow the growth of mammary gland cancer in rodent models. Since exposure to dietary components during the critical developmental times of gestation and lactation may alter risk for mammary gland cancer in females, we tested whether exposure to increased levels of long-chain omega-3 fatty acids from fish oils would be preventive or promotional to mammary gland cancer in the offspring.

METHODS

Normal SV129 female mice were fed AIN 76 diets containing either 10% corn oil (control, 50% omega 6, n-6) or 5% of an omega-3 (n-3) fatty acid concentrate (fish oil 60% n-3) + 5% canola oil (10% n-3 + 20% n-6). Females were then mated with C(3)1 TAg transgenic mice. At weaning (3 weeks), pups were randomized to either the corn (C) or fish oil (F) diet, 15-17 mice per group. Four experimental groups were generated: FF, FC, CF and CC. Tumor incidence and multiplicity were assessed at the following time points 120, 130 and 140 days of age. A panel of genes encoding signal transduction proteins were analyzed in mammary glands at 130 days.

RESULTS

Mice never exposed to fish oil (CC group) had a significantly higher incidence and multiplicity of mammary gland tumors than mice exposed to fish oil throughout life (FF group). Mice exposed to fish oil during a portion of life (CF or FC) had intermediate tumor incidences and multiplicities. Results also indicate that maternal consumption of fish oil increased the expression of genes associated with immune system activation (Ccl20, Cd5, Il2, Lef1, Lta).

CONCLUSIONS

Adequate omega-3 fatty acids in the maternal diet may reduce the risk for mammary gland cancer in the offspring. If humans make dietary change by consuming more omega-3 fat instead of corn oil with 0% omega 3 fat, breast cancer may be reduced in the next generation.

Genistein Reduces the Risk of Local Mammary Cancer Recurrence and Ameliorates Alterations in the Gut Microbiota in the Offspring of Obese Dams

The risk of recurrence of estrogen receptor-positive breast cancer remains constant, even 20 years after diagnosis. Recurrence may be more likely in patients pre-programmed for it already in the womb, such as in the daughters born to obese mothers. Maternal obesity persistently alters offspring’s gut microbiota and impairs tumor immune responses. To investigate if the gut dysbiosis is linked to increased risk of mammary cancer recurrence in the offspring of obese rat dams, we fed adult offspring genistein which is known to have beneficial effects on the gut bacteria. However, the effects of genistein on breast cancer remain controversial. We found that genistein intake after tamoxifen response prevented the increased risk of local recurrence in the offspring of obese dams but had no effect on the control offspring. A significant increase in the abundance of inflammatory Prevotellaceae and Enterobacteriaceae, and a reduction in short-chain fatty acid producing Clostridiaceae was observed in the offspring of obese dams. Genistein supplementation reversed these changes as well as reversed increased gut metabolite N-acetylvaline levels which are linked to increased all-cause mortality. Genistein supplementation also reduced genotoxic tyramine levels, increased metabolites improving pro-resolving phase of inflammation, and reversed the elevated tumor mRNA expression of multiple immunosuppressive genes in the offspring of obese dams. If translatable to breast cancer patients, attempts to prevent breast cancer recurrences might need to focus on dietary modifications which beneficially modify the gut microbiota.