Resistin facilitates breast cancer progression via TLR4-mediated induction of mesenchymal phenotypes and stemness properties

Beyond blood pressure, fluid and electrolyte homeostasis - Role of the renin angiotensin aldosterone system in the interplay between metabolic diseases and breast cancer

The classical renin angiotensin aldosterone system (RAAS), as well as the recently described counter-regulatory or non-canonical RAAS have been well characterized for their role in cardiovascular homeostasis. Moreover, extensive research has been conducted over the past decades on both paracrine and the endocrine roles of local RAAS in various metabolic regulations and in chronic diseases. Clinical evidence from patients on RAAS blockers as well as pre-clinical studies using rodent models of genetic manipulations of RAAS genes documented that this system may play important roles in the interplay between metabolic diseases and cancer, namely breast cancer. Some of these studies suggest potential therapeutic applications and repurposing of RAAS inhibitors for these diseases. In this review, we discuss the mechanisms by which RAAS is involved in the pathogenesis of metabolic diseases such as obesity and type-2 diabetes as well as the role of this system in the initiation, expansion and/or progression of breast cancer, especially in the context of metabolic diseases.

Butyrate inhibits the malignant biological behaviors of breast cancer cells by facilitating cuproptosis-associated gene expression

BACKGROUND

Butyrate is a common short-chain fatty acids (SCFA), and it has been demonstrated to regulate the development of breast cancer (BC), while the underlying mechanism is still unreported.

METHODS

Gas chromatography was used to measure the amounts of SCFA (acetate, propionate, and butyrate) in the feces. Cell viability was measured by the CCK-8 assay. The wound healing assay demonstrated cell migration, and the transwell assay demonstrated cell invasion. The levels of protein and gene were determined by western blot assay and RT-qPCR assay, respectively.

RESULTS

The levels of SCFA were lower in the faecal samples from BC patients compared to control samples. In cellular experiments, butyrate significantly suppressed the cell viability, migration and invasion of T47D in a dose-dependent manner. In animal experiments, butyrate effectively impeded the growth of BC tumors. Toll like receptor 4 (TLR4) was highly expressed in the tumors from BC patients. Butyrate inhibited the expression of TLR4. In addition, butyrate promoted the expression of cuproptosis-related genes including PDXK (pyridoxal kinase) and SLC25A28 (solute carrier family 25 member 28), which was lowly expressed in BC tumors. Importantly, overexpression of TLR4 can reverses the promotion of butyrate to PDXK and SLC25A28 expression and the prevention of butyrate to the malignant biological behaviors of T47D cells.

CONCLUSION

In summary, butyrate inhibits the development of BC by facilitating the expression of PDXK and SLC25A28 through inhibition of TLR4. Our investigation first identified a connection among butyrate, TLR4 and cuproptosis-related genes in BC progression. These findings may provide novel target for the treatment of BC.

Clinicopathological Significance and Prognostic Role of High Mobility Group Box 1 (HMGB1), Toll-Like Receptor (TLR) 2 and TLR4 in Breast Cancer

High-mobility group box 1 (HMGB1) functions as damage-associated molecular pattern (DAMPs), released into extracellular space during cellular stress. Extracellular HMGB1 act as signal molecules through Toll-like receptor (TLR) 2 or TLR4, exerting diverse functions in both normal cells and malignant cells including breast cancer. However, their comprehensive examination in breast cancer tissues is lacking. Thus, we immunolocalized them in 112 breast cancer tissues, correlating their immunoreactivity with clinicopathological parameters and clinical outcomes to clarify their significance in breast cancer. We demonstrated that nuclear HMGB1 immunoreactivity was correlated with tumor progression and longer disease-free survival. In contrast, TLR2 immunoreactivity was correlated with increased cell proliferation and shorter disease-free survival, dependent on cytoplasmic HMGB1 immunoreactivity. Additionally, TLR4 immunoreactivity correlated with chemoresistance, regardless of cytoplasmic HMGB1 immunoreactivity. It was therefore considered that TLR2 collaboratively contributed to breast cancer progression with HMGB1-DAMPs to become a worse prognostic factor. Meanwhile, TLR4 served as a worse prognostic factor associated with chemoresistance, irrespective of HMGB1.

Crosstalk between obesity and cancer: a role for adipokines

Adipose tissue is a complex organ that is increasingly being recognised as the largest endocrine organ in the body. Adipocytes among multiple cell types of adipose tissue can secrete a variety of adipokines, which are involved in signalling pathways and these can be changed by obesity and cancer. There are proposed mechanisms to link obesity/adiposity to cancer development including adipocytokine dysregulation. Among these adipokines, leptin acts through multiple pathways including the STAT3, MAPK, and PI3K pathways involved in cell growth. Adiponectin has the opposite action from leptin in tumour growth partly because of increased apoptotic responses of p53 and Bax. Visfatin increases cancer cell proliferation through ERK1/2, PI3K/AKT, and p38 which are stimulated by proinflammatory cytokines. Omentin through the PI3K/Akt-Nos pathway is involved in cancer-tumour development. Apelin might be involved through angiogenesis in tumour progressions. PAI-1 via its anti-fibrinolytic activity on cell adhesion and uPA/uPAR activity influence cancer cell growth.

The effect of resistin on the redox state of breast cancer cells

PURPOSE

Resistin is an inflammatory cytokine secreted mostly by adipocytes and immune cells that plays a role in the development of insulin resistance, diabetes, and cancer. We hypothesized that resistin's inflammatory activity influences the free radical and oxidative stress pathways.

METHODS

We used human breast carcinogenic (MCF-7 and MDA-MB-231) and non-carcinogenic (MCF-10A) cells in this investigation and correlated the absorbed resistin concentration with the change in oxidative stress (TBARS, carbonated proteins) and antioxidant activity (Antioxidant Capacity, SuperOxideDismutase, CATalase, Glutathione Peroxidase).

RESULTS

Resistin was substantially more effective as a prooxidant at lower (12.5 ng/ml) concentrations, than at higher concentrations (25.0 ng/ml). Vitamin C did not appear to be an effective oxidative stress protector at antioxidant concentrations of 5.10-4 M. Leptin, at 100 ng/ml, did not result in conclusive oxidative stress or antioxidant defence stimulation, as expected.

CONCLUSION

Taken together, the findings support resistin's role as a non-oxidative stress marker and a metabolic signaling molecule.

The relation between excess adiposity and breast cancer in women: Clinical implications and management

BACKGROUND

Breast cancer (BC) is the most common cancer in women. While the combination of improved screening, earlier detection, and advances in therapeutics has resulted in lower BC mortality, BC survivors are now increasingly dying of cardiovascular disease. Cardiovascular disease in the leading cause of non-cancer related mortality among BC survivors. This situation underscores the critical need to research the role of modifiable cardiometabolic risk factors, such as excess adiposity, that will affect BC remission, long-term survivorship, and overall health and quality of life.

PURPOSE

First, this review summarizes the evidence on the connection between adipose tissue and BC. Then we review the data on weight trends after BC diagnosis with a focus on the effect of weight gain on BC recurrence and BC- and non-BC-related death. Finally, we provide a guide for weight management in BC survivors, considering the available data on the effect of weight loss interventions on BC.

Resistin Induces Migration and Invasion in PC3 Prostate Cancer Cells: Role of Extracellular Vesicles

Resistin is an adipokine with metabolic and inflammatory functions. Epidemiological and translational studies report that an increase in plasma levels and tissue expression of resistin increases the aggressiveness of prostate tumor cells. Extracellular vesicles (EVs) are secreted constitutively and induced by cytokines, growth factors, and calcium and are found in multiple biological fluids such as saliva, serum, semen, and urine. In particular, EVs have been shown to promote tumor progression through the induction of proliferation, growth, angiogenesis, resistance to chemotherapy, and metastasis. However, the role of resistin in the migration, invasion, and secretion of EVs in invasive prostate tumor cells remains to be studied. In the present study, we demonstrate that resistin induces increased migration and invasion in PC3 cells. In addition, these phenomena are accompanied by increased p-FAK levels and increased secretion of MMP-2 and MMP-9 in resistin-treated PC3 cells. Interestingly, EVs isolated from supernatants of PC3 cells treated with resistin induce an increase in migration and invasion accompanied by high MMP-2 and MMP-9 secretion in an autocrine stimulation model. In summary, our data for the first time demonstrate that resistin induces migration and invasion, partly through the secretion of EVs with pro-invasive characteristics in PC3 cells.

Correlation of plasma adipokines with endometrial atypical hyperplasia and type I/II endometrial cancer

The aim of the study was to systematically explore the relationships between various adipokines and risks of endometrial atypical hyperplasia (EAH), type I endometrial cancer (EC), and type II EC. We enrolled 219 patients in this study, including 39 EAH, 87 type I EC, 38 type II EC and 55 control individuals. We subsequently explored the association of adipokine levels and the leptin-to-adiponectin (L/A) ratio with EAH, type I EC, and type II EC. The plasma leptin level and L/A ratio were significantly higher in the EAH group than in the control group (p = 0.012). Leptin, resistin, vaspin, and visfatin levels were significantly higher in the type I EC group; however, the adiponectin level was lower in the type I EC, which resulted in a higher L/A ratio. Notably, the L/A ratio and visfatin level in the type II EC group were significantly higher. Multiple logistic regression analysis revealed that a higher leptin level was significantly associated with a higher EAH risk (p = 0.012). Higher leptin level (p = 0.042) and L/A ratio (p = 0.027) were significantly associated with an increased type I EC risk. By contrast, higher leptin (p = 0.059) and visfatin (p = 0.003) levels, higher L/A ratio (p = 0.033), and lower adiponectin level (p = 0.042) were associated with an increased type II EC risk. We suggested that adipokines are potentially correlated with EAH and EC risks.

Detoxified pneumolysin derivative ΔA146Ply inhibits triple- negative breast cancer metastasis mainly via mannose receptor-mediated autophagy inhibition

The detoxified pneumolysin derivative ΔA146Ply has been proven to have a direct anti-triple negative breast cancer effect by our group, but its work model remains unclear. In this study, we focused on its ability to inhibit triple-negative breast cancer metastasis. We found that ΔA146Ply suppressed the migration and invasion of triple-negative breast cancer cells by activating mannose receptor and toll-like receptor 4. Their activation triggers the activation of the mammalian target of rapamycin signaling, sequentially leading to autophagy, transforming growth factor-β1, and epithelial-mesenchymal transition inhibition. Furthermore, the combination of doxorubicin and ΔA146Ply significantly inhibited triple-negative breast cancer progression and prolonged survival in tumor-bearing mice. Taken together, our study provides an alternative microbiome-based mannose receptor-targeted therapy for triple-negative breast cancer and a novel theoretical and experimental basis for the downstream signaling pathway of the mannose receptor.

Adipocyte regulation of cancer stem cells

Cancer stem cells (CSCs) are a highly tumorigenic subpopulation of the cancer cells within a tumor that drive tumor initiation, progression, and therapy resistance. In general, stem cell niche provides a specific microenvironment in which stem cells are present in an undifferentiated and self-renewable state. CSC niche is a specialized tumor microenvironment for CSCs which provides cues for their maintenance and propagation. However, molecular mechanisms for the CSC-niche interaction remain to be elucidated. We have revealed that adipsin (complement factor D) and its downstream effector hepatocyte growth factor are secreted from adipocytes and enhance the CSC properties in breast cancers in which tumor initiation and progression are constantly associated with the surrounding adipose tissue. Considering that obesity, characterized by excess adipose tissue, is associated with an increased risk of multiple cancers, it is reasonably speculated that adipocyte-CSC interaction is similarly involved in many types of cancers, such as pancreas, colorectal, and ovarian cancers. In this review, various molecular mechanisms by which adipocytes regulate CSCs, including secretion of adipokines, extracellular matrix production, biosynthesis of estrogen, metabolism, and exosome, are discussed. Uncovering the roles of adipocytes in the CSC niche will propose novel strategies to treat cancers, especially those whose progression is linked to obesity.

Adipokines and epithelial-mesenchymal transition (EMT) in cancer

Obesity is a significant risk factor for cancer development. Within the tumor microenvironment, adipocytes interact with cancer cells, immune cells, fibroblasts and endothelial cells, and orchestrate several signaling pathways by secreting bioactive molecules, including adipokines. Adipokines or adipocytokines are produced predominantly by adipocytes and function as autocrine, paracrine and endocrine mediators. Adipokines can exert pro- and anti-inflammatory functions, and they play a pivotal role in the state of chronic low-grade inflammation that characterizes obesity. Epithelial-mesenchymal transition (EMT), a complex biological process whereby epithelial cells acquire the invasive, migratory mesenchymal phenotype is well-known to be implicated in cancer progression and metastasis. Emerging evidence suggests that there is a link between adipokines and EMT. This may contribute to the correlation that has been documented between obesity and cancer progression. This review summarizes the existing body of evidence supporting an association between the process of EMT in cancer and the adipokines leptin, adiponectin, resistin, visfatin/NAMPT, lipocalin-2/NGAL, as well as other newly discovered adipokines including chemerin, nesfatin-1/nucleobindin-2, AZGP1, SFRP5 and FABP4.

The Role of Obesity in Breast Cancer Pathogenesis

Research has shown that obesity increases the risk for type 2 diabetes mellitus (Type 2 DM) by promoting insulin resistance, increases serum estrogen levels by the upregulation of aromatase, and promotes the release of reactive oxygen species (ROS) by macrophages. Increased circulating glucose has been shown to activate mammalian target of rapamycin (mTOR), a significant signaling pathway in breast cancer pathogenesis. Estrogen plays an instrumental role in estrogen-receptor-positive breast cancers. The role of ROS in breast cancer warrants continued investigation, in relation to both pathogenesis and treatment of breast cancer. We aim to review the role of obesity in breast cancer pathogenesis and novel therapies mediating obesity-associated breast cancer development. We explore the association between body mass index (BMI) and breast cancer incidence and the mechanisms by which oxidative stress modulates breast cancer pathogenesis. We discuss the role of glutathione, a ubiquitous antioxidant, in breast cancer therapy. Lastly, we review breast cancer therapies targeting mTOR signaling, leptin signaling, blood sugar reduction, and novel immunotherapy targets.

Serum resistin and the risk for hepatocellular carcinoma in diabetic patients

Hepatocellular carcinoma (HCC), the predominant type of liver cancer, is a major contributor to cancer-related fatalities across the globe. Diabetes has been identified as a significant risk factor for HCC, with recent research indicating that the hormone resistin could be involved in the onset and advancement of HCC in diabetic individuals. Resistin is a hormone that is known to be involved in inflammation and insulin resistance. Patients with HCC have been observed to exhibit increased resistin levels, which could be correlated with more severe disease stages and unfavourable prognoses. Nevertheless, the exact processes through which resistin influences the development and progression of HCC in diabetic patients remain unclear. This article aims to examine the existing literature on the possible use of resistin levels as a biomarker for HCC development and monitoring. Furthermore, it reviews the possible pathways of HCC initiation due to elevated resistin and offers new perspectives on comprehending the fundamental mechanisms of HCC in diabetic patients. Gaining a better understanding of these processes may yield valuable insights into HCC’s development and progression, as well as identify possible avenues for prevention and therapy.

Changes in the mammary gland during aging and its links with breast diseases

The functional capacity of organisms declines in the process of aging. In the case of breast tissue, abnormal mammary gland development can lead to dysfunction in milk secretion, a primary function, as well as the onset of various diseases, such as breast cancer. In the process of aging, the terminal duct lobular units (TDLUs) within the breast undergo gradual degeneration, while the proportion of adipose tissue in the breast continues to increase and hormonal levels in the breast change accordingly. Here, we review changes in morphology, internal structure, and cellular composition that occur in the mammary gland during aging. We also explore the emerging mechanisms of breast aging and the relationship between changes during aging and breast-related diseases, as well as potential interventions for delaying mammary gland aging and preventing breast disease.

Bone serves as a transfer station for secondary dissemination of breast cancer

Metastasis is responsible for the majority of deaths among breast cancer patients. Although parallel polyclonal seeding has been shown to contribute to organ-specific metastasis, in the past decade, horizontal cross-metastatic seeding (metastasis-to-metastasis spreading) has also been demonstrated as a pattern of distant metastasis to multiple sites. Bone, as the most frequent first destination of breast cancer metastasis, has been demonstrated to facilitate the secondary dissemination of breast cancer cells. In this review, we summarize the clinical and experimental evidence that bone is a transfer station for the secondary dissemination of breast cancer. We also discuss the regulatory mechanisms of the bone microenvironment in secondary seeding of breast cancer, focusing on stemness regulation, quiescence-proliferation equilibrium regulation, epigenetic reprogramming and immune escape of cancer cells. Furthermore, we highlight future research perspectives and strategies for preventing secondary dissemination from bone.

The molecular link between obesity and genomic instability in cancer development

Obesity has been known to be a major risk factor for various types of cancers for several decades. More recently, the relationship between dysregulated adipokines and cancer development has been the focus of much research. Adipose tissue is an important endocrine organ that secretes adipokines that affect both autocrine and paracrine signaling. These adipokines modulate inflammation, induce insulin resistance, and regulate their own behavior and production. Adipokine-production dysregulation is due to physiological changes in adipose tissue that prompt molecular modifications, including low-grade inflammation and the stimulatory production of reactive oxygen species. Additionally, studies have linked DNA damage response, genomic instability, and the innate immune response to tumorigenesis. Further investigation of adipokines and their role in the promotion of genomic instability may clarify the link between obesity and cancer, as well as elucidate potential pharmaceutical targets. In this review, we discuss the progress of recent literature, focusing on the impact of adipokines, genomic instability, and the innate immune response on increasing the risk of cancer.

Fumarate hydratase inhibits non-small cell lung cancer metastasis via inactivation of AMPK and upregulation of DAB2

Lung cancer is one of the leading causes of cancer mortality worldwide. As it is often first diagnosed only when cancer metastasis has already occurred, the development of effective biomarkers for the risk prediction of cancer metastasis, followed by stringent monitoring and the early treatment of high-risk patients, is essential for improving patient survival. Cancer cells exhibit alterations in metabolic pathways that enable them to maintain rapid growth and proliferation, which are quite different from the metabolic pathways of normal cells. Fumarate hydratase (FH, fumarase) is a well-known tricarboxylic acid cycle enzyme that catalyzes the reversible hydration/dehydration of fumarate to malate. The current study sought to investigate the relationship between FH expression levels and the outcome of patients with lung cancer. FH was knocked down in lung cancer cells using shRNA or overexpressed using a vector, and the effect on migration ability was assessed. Furthermore, the role of AMP-activated protein kinase (AMPK) phosphorylation and disabled homolog 2 in the underlying mechanism was investigated using an AMPK inhibitor approach. The results showed that in lung cancer tissues, low FH expression was associated with lymph node metastasis, tumor histology and recurrence. In addition, patients with low FH expression exhibited a poor overall survival in comparison with patients having high FH expression. When FH was overexpressed in lung cancer cells, cell migration was reduced with no effect on cell proliferation. Furthermore, the level of phosphorylated (p-)AMPK, an energy sensor molecule, was upregulated when FH was knocked down in lung cancer cells, and the inhibition of p-AMPK led to an increase in the expression of disabled homolog 2, a tumor suppressor protein. These findings suggest that FH may serve as an effective biomarker for predicting the prognosis of lung cancer and as a therapeutic mediator.

Resistin Promotes Nasopharyngeal Carcinoma Metastasis through TLR4-Mediated Activation of p38 MAPK/NF-κB Signaling Pathway

NPC is a type of malignant tumor with a high risk of local invasion and early distant metastasis. Resistin is an inflammatory cytokine that is predominantly produced from the immunocytes in humans. Accumulating evidence has suggested a clinical association of circulating resistin with the risk of tumorigenesis and a relationship between blood resistin levels and the risk of cancer metastasis. In this study, we explored the blood levels and the role of resistin in NPC. High resistin levels in NPC patients were positively associated with lymph node metastasis, and resistin promoted the migration and invasion of NPC cells in vitro. These findings were also replicated in a mouse model of NPC tumor metastasis. We identified TLR4 as a functional receptor in mediating the pro-migratory effects of resistin in NPC cells. Furthermore, p38 MAPK and NF-κB were intracellular effectors that mediated resistin-induced EMT. Taken together, our results suggest that resistin promotes NPC metastasis by activating the TLR4/p38 MAPK/NF-κB signaling pathways.

The impact of obesity and adipokines on breast and gynecologic malignancies

The link between obesity and multiple disease comorbidities is well established. In 2003, Calle and colleagues presented the relationship between obesity and several cancer types, including breast, ovarian, and endometrial malignancies. Nearly, 20% of cancer-related deaths in females can be accounted for by obesity. Identifying obesity as a risk factor for cancer led to a focus on the role of fat-secreted cytokines, known as adipokines, on carcinogenesis and tumor progression. Early studies indicated that the adipokine leptin increases cell proliferation, invasion, and inhibition of apoptosis in multiple cancer types. As a greater appreciation of the obesity-cancer link has amassed, we now know that additional adipokines can impact tumorigenesis. A deeper understanding of the adipokine-activated signaling in cancer may identify new treatment strategies irrespective of obesity. Moreover, adipokines may serve as disease biomarkers, harnessing the potential of obesity-associated factors to serve as indicators of treatment response and disease prognosis. As studies investigating obesity and women's cancers continue to expand, it has become evident that breast, ovarian, and uterine cancers are distinctly impacted by adipokines. While complex, these distinct interactions may provide insight into cancer progression in these organs and new opportunities for targeted therapies. This review aims to organize and present the literature from the last 5 years investigating the mechanisms and implications of adipokine signaling in breast, endometrial, and ovarian cancers with a special focus on leptin and adiponectin.

The pleiotropic roles of adipocyte secretome in remodeling breast cancer

Background

Breast cancer is the leading female cancer type and the cause of cancer-related mortality worldwide. Adipocytes possess important functions of energy supply, metabolic regulation, and cytokine release, and are also the matrix cell that supports mammary gland tissue. In breast cancer tumor microenvironment (TME), adipocytes are the prominent stromal cells and are implicated in inflammation, metastatic formation, metabolic remodeling, and cancer susceptibility.

Main body

It is well-established that adipocyte secretome is a reservoir engaged in the regulation of tumor cell behavior by secreting a large number of cytokines (IL-6, IL-8, and chemokines), adipokines (leptin, adiponectin, autotaxin, and resistin), lipid metabolites (free fatty acids and β-hydroxybutyrate), and other exosome-encapsulated substances. These released factors influence the evolution and clinical outcome of breast cancer through complex mechanisms. The progression of breast cancer tumors revolves around the tumor-adipose stromal network, which may contribute to breast cancer aggressiveness by increasing the pro-malignant potential of TME and tumor cells themselves. Most importantly, the secretome alterations of adipocytes are regarded as distinctly important targets for breast cancer diagnosis, treatment, and drug resistance.

Conclusion

Therefore, this review will provide a comprehensive description of the specific adipocyte secretome characteristics and interactions within TME cell populations, which will enable us to better tailor strategies for tumor stratification management and treatment.

Adiponectin Suppresses Metastasis of Nasopharyngeal Carcinoma through Blocking the Activation of NF-κB and STAT3 Signaling

Adiponectin is an adipocytokine with anti-inflammatory and anticancer properties. Our previous study has shown that blood adiponectin levels were inversely correlated to the risk of nasopharyngeal carcinoma (NPC), and that adiponectin could directly suppress the proliferation of NPC cells. However, the effect of adiponectin on NPC metastasis remains unknown. Here, we revealed in clinical studies that serum adiponectin level was inversely correlated with tumor stage, recurrence, and metastasis in NPC patients, and that low serum adiponectin level also correlates with poor metastasis-free survival. Coculture with recombinant adiponectin suppressed the migration and invasion of NPC cells as well as epithelial-mesenchymal transition (EMT). In addition, recombinant adiponectin dampened the activation of NF-κB and STAT3 signaling pathways induced by adipocyte-derived proinflammatory factors such as leptin, IL-6, and TNF-α. Pharmacological activation of adiponectin receptor through its specific agonist, AdipoRon, largely stalled the metastasis of NPC cells. Taken together, these findings demonstrated that adiponectin could not only regulate metabolism and inhibit cancer growth, but also suppress the metastasis of NPC. Pharmacological activation of adiponectin receptor may be a promising therapeutic strategy to stall NPC metastasis and extend patients' survival.

ADSCs stimulated by resistin promote breast cancer cell malignancy via CXCL5 in a breast cancer coculture model

The tumor microenvironment represents one of the main obstacles in breast cancer treatment owing to the presence of heterogeneous stromal cells, such as adipose-derived stem cells (ADSCs), that may interact with breast cancer cells and promote cancer development. Resistin is an adipocytokine associated with adverse breast cancer progression; however, its underlying mechanisms in the context of the breast tumor microenvironment remain largely unidentified. Here, we utilized a transwell co-culture model containing patient-derived ADSCs and breast cancer cell lines to investigate their potential interaction, and observed that breast cancer cells co-cultured with resistin-treated ADSCs (R-ADSCs) showed enhanced cancer cell growth and metastatic ability. Screening by proteome arrays revealed that C-X-C motif chemokine ligand 5 (CXCL5) was released in the conditioned medium of the co-culture system, and phosphorylated ERK was increased in breast cancer cells after co-culture with R-ADSCs. Breast cancer cells treated with the recombinant proteins of CXCL5 showed similarly enhanced cell migration and invasion ability as occurred in the co-culture model, whereas application of neutralizing antibodies against CXCL5 reversed these phenomena. The orthotopic xenograft in mice by breast cancer cells after co-culture with R-ADSCs had a larger tumor growth and more CXCL5 expression than control. In addition, clinical analysis revealed a positive correlation between the expression of resistin and CXCL5 in both tumor tissues and serum specimens of breast cancer patients. The current study suggests that resistin-stimulated ADSCs may interact with breast cancer cells in the tumor microenvironment via CXCL5 secretion, leading to breast cancer cell malignancy.

Adipose tissue-to-breast cancer crosstalk: Comprehensive insights

The review focuses on mechanistic evidence for the link between obesity and breast cancer. According to the IARC study, there is sufficient evidence that obesity is closely related to a variety of cancers. Among them, breast cancer is particularly disturbed by adipose tissue due to the unique histological structure of the breast. The review introduces the relationship between obesity and breast cancer from two aspects, including factors that promote tumorigenesis or metastasis. We summarize alterations in adipokines and metabolic pathways that contribute to breast cancer development. Breast cancer metastasis is closely related to obesity-induced pro-inflammatory microenvironment, adipose stem cells, and miRNAs. Based on the mechanism by which obesity causes breast cancer, we list possible therapeutic directions, including reducing the risk of breast cancer and inhibiting the progression of breast cancer. We also discussed the risk of autologous breast remodeling and fat transplantation. Finally, the causes of the obesity paradox and the function of enhancing immunity are discussed. Evaluating the balance between obesity-induced inflammation and enhanced immunity warrants further study.

Altered Adipokine Expression in Tumor Microenvironment Promotes Development of Triple Negative Breast Cancer

Obesity is a remarkably important factor for breast carcinogenesis and aggressiveness. The implication of increased BMI in triple negative breast cancer (TNBC) development is also well established. A malignancy-promoting role of the adipose tissue has been supposed, where the adipocytes that constitute the majority of stromal cells release pro-inflammatory cytokines and growth factors. Alterations in adipokines and their receptors play significant roles in breast cancer initiation, progression, metastasis, and drug response. Classic adipokines, such as leptin, adiponectin, and resistin, have been extensively studied in breast cancer and connected with breast cancer risk and progression. Notably, new molecules are constantly being discovered and the list is continuously growing. Additionally, substantial progress has been made concerning their differential expression in association with clinical and pathological parameters of tumors and the prognostic and predictive value of their dysregulation in breast cancer carcinogenesis. However, evidence regarding the mechanisms by which adipose tissue is involved in the development of TNBC is lacking. In the present article we comment on current data on the suggested involvement of these mediators in breast cancer development and progression, with particular emphasis on TNBC, to draw attention to the design of novel targeted therapies and biomarkers.

Hormonal Crosstalk Between Thyroid and Breast Cancer

Differentiated thyroid cancer and breast cancer account for a significant portion of endocrine-related malignancies and predominately affect women. As hormonally responsive tissues, the breast and thyroid share endocrine signaling. Breast cells are responsive to thyroid hormone signaling and are affected by altered thyroid hormone levels. Thyroid cells are responsive to sex hormones, particularly estrogen, and undergo protumorigenic processes upon estrogen stimulation. Thyroid and sex hormones also display significant transcriptional crosstalk that influences oncogenesis and treatment sensitivity. Obesity-related adipocyte alterations-adipocyte estrogen production, inflammation, feeding hormone dysregulation, and metabolic syndromes-promote hormonal alterations in breast and thyroid tissues. Environmental toxicants disrupt endocrine systems, including breast and thyroid homeostasis, and influence pathologic processes in both organs through hormone mimetic action. In this brief review, we discuss the hormonal connections between the breast and thyroid and perspectives on hormonal therapies for breast and thyroid cancer. Future research efforts should acknowledge and further explore the hormonal crosstalk of these tissues in an effort to further understand the prevalence of thyroid and breast cancer in women and to identify potential therapeutic options.

The Role of the Adipokine Resistin in the Pathogenesis and Progression of Epithelial Ovarian Cancer

Obesity is a civilization disease associated with an increased risk of developing cardiovascular diseases, diabetes, and some malignancies. The results concerning the relationship between obesity and epithelial ovarian cancer (EOC) are inconclusive. The higher incidence of neoplasms in obese subjects has led to the development of the adipokine hypothesis. Omental adipocyte cells interact with cancer cells, promoting their migration and metastasis via the secretion of adipokines, growth factors, and hormones. One of the adipokines is resistin. It was shown in vitro that resistin stimulates the growth and differentiation of ovarian cancer cells. Moreover, it increases the level of angiogenesis factors, e.g., matrix metalloproteinase 2 (MMP-2) and vascular epithelial growth factor (VEGF). Additionally, resistin induces epithelial–mesenchymal transition (EMT) and stemness in EOC cell lines. A positive correlation has been shown between a higher level of resistin expression and the stage of histological differentiation of EOC or the occurrence of lymph node metastases. In addition, the overexpression of resistin has been found to act as an independent factor determining disease-free survival as well as overall survival in EOC patients. Growing evidence supports the finding that resistin plays an important role in some mechanisms leading to the progression of EOC, though this issue still requires further research.

MD2 Is a Potential Biomarker Associated with Immune Cell Infiltration in Gliomas

Background

Glioma is the most common primary malignant tumor in the central nervous system. Myeloid differentiation protein 2 (MD2) acts as a coreceptor of toll-like receptor 4 (TLR4) to mediate innate immune response. However, the actual roles of MD2 in the regulation of progression and immune cell infiltration in gliomas remain largely unclear. This study aims to explore whether MD2 could be an independent prognostic factor through the mediation of immune cell infiltration in gliomas.

Methods

The mRNA expression and DNA methylation differential analyses of MD2 were performed using CGGA, TCGA and Rembrandt databases and survival analyses were performed using Kaplan-Meier plotter. Univariate and multivariate Cox regression was applied to analyze the prognostic value of MD2 and nomograms were constructed to evaluate the clinical value of MD2. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were utilized to analyze MD2-related signal pathways. Furthermore, correlations between MD2 and immune cell infiltration were calculated by TIMER and CIBERSOPT. The correlation between MD2 expression and the infiltrations of macrophages and neutrophils was experimentally verified by the knockdown of MD2 expression using small interfering RNA (siRNA) in glioma cells.

Results

We found that MD2 was overexpressed and associated with a poor prognosis in gliomas. Meanwhile, higher expression of MD2 could be a result of lower DNA methylation of MD2 gene in gliomas. In addition, univariate and multivariate Cox regression analysis indicated that MD2 could be an independent prognostic factor for gliomas. Further functional enrichment analysis revealed that the functions of MD2 were closely related to immune responses. Moreover, the expression level of MD2 was strongly correlated with the infiltration and polarization of pro-tumor phenotype of tumor-associated macrophages and tumor-associated neutrophils in gliomas.

Conclusions

These findings have provided strong evidence that MD2 could be served as a valuable immune-related biomarker to diagnose and predict the progression of gliomas.

The first combined meta‐analytic approach for elucidating the relationship of circulating resistin levels and RETN gene polymorphisms with colorectal and breast cancer

Background

Evidence suggests that circulating resistin levels are altered in colorectal cancer (CRC) and breast cancer (BC). Again, polymorphisms in resistin-encoding gene RETN have been evaluated in CRC and BC. However, there is a scarcity of data establishing the relationship of resistin and RETN polymorphisms (rs1862513 and rs3745367) with these cancers. This study aimed to analyze the relationship of resistin levels and RETN polymorphisms with CRC and BC in a combined meta-analytic approach.

Main body of the abstract

After a comprehensive online literature search, screening and eligibility check, 41 articles (31 with resistin level and 10 with RETN polymorphisms) were retrieved for meta-analyses. The mean difference (MD) of resistin was calculated and pooled to investigate the effect sizes with a 95% confidence interval (CI), and the connection of genetic polymorphisms was analyzed with an odds ratio (OR) and 95% CI. The analysis showed that resistin level is significantly higher in CRC (MD = 3.39) and BC (MD = 3.91) patients. Subgroup analysis in CRC showed significantly higher resistin in serum (MD = 4.61) and plasma (MD = 0.34), and in BC, a significantly elevated resistin level was reported in premenopausal (MD = 7.82) and postmenopausal (MD = 0.37) patients. Again, RETN rs1862513 showed a significantly strong association with CRC (codominant 1—OR 1.24, codominant 2—OR 1.31, dominant model—OR 1.25, and allele model—OR 1.16) and with BC (codominant 2—OR 1.51, codominant 3—OR 1.51, recessive model—OR 1.51, and allele model—OR 1.21). RETN rs3745367 did not show any association with these cancers.

Short conclusion

Overall, our analysis indicates that higher circulating resistin levels are associated with an elevated risk of CRC and premenopausal and postmenopausal BC. Besides, rs1862513 in RETN gene is significantly connected with both CRC and BC.

Importance of circulating adipocytokines in multiple myeloma: a systematic review and meta-analysis based on case-control studies

BACKGROUND

Adipocytes and their products, adipocytokines, play important roles in the generation and development of multiple myeloma (MM). Studies have demonstrated some adipocytokines to be associated with MM, although those results are controversial. Therefore, we conducted a meta-analysis to verify the association of adipocytokines with MM.

METHODS

We performed a systematic retrieval of literature published prior to 26 October 2021. Standardized mean difference (SMD) with a 95% confidence interval (CI) was calculated to evaluate pooled effects. Subgroup analysis and meta-regression analysis were conducted to detect sources of heterogeneity. Sensitivity analysis was performed to evaluate the stability of the study. Publication bias was assessed by funnel plots and Egger's linear regression test.

RESULTS

Ten eligible studies with 1269 MM patients and 2158 controls were included. The pooled analyses indicated that circulating leptin levels of MM patients were significantly higher than control levels (SMD= 0.87, 95%CI: 0.33 to 1.41), while the circulating adiponectin levels in MM patients were significantly lower than controls with a pooled SMD of -0.49 (95%CI: -0.78 to -0.20). The difference of circulating resistin levels were not significant between MM patients and controls (SMD= -0.08, 95%CI: -0.55 to 0.39). Subgroup analysis and meta-regression analysis found that sample size, age, and sex were possible sources of heterogeneity. Sensitivity analysis demonstrated our pooled results to be stable.

CONCLUSION

Decreased circulating adiponectin and increased leptin levels were associated with the occurrence and development of MM. Adiponectin and leptin may be potential biomarkers and therapeutic targets for MM.

Local Biomarkers Involved in the Interplay between Obesity and Breast Cancer

Simple Summary

Breast cancer is the second most common cancer in women worldwide. The risk of developing breast cancer depends on various mechanisms, such as age, heredity, reproductive factors, physical inactivity, and obesity. Obesity increases the risk of breast cancer and worsens outcomes for breast cancer patients. The rate of obesity is increasing worldwide, stressing the need for awareness of the association between obesity and breast cancer. In this review, we outline the biomarkers—including cellular and soluble factors—in the breast, associated with obesity, that affect the risk of breast cancer and breast cancer prognosis. Through these biomarkers, we aim to better identify patients with obesity with a higher risk of breast cancer and an inferior prognosis.

Abstract

Obesity is associated with an increased risk of breast cancer, which is the most common cancer in women worldwide (excluding non-melanoma skin cancer). Furthermore, breast cancer patients with obesity have an impaired prognosis. Adipose tissue is abundant in the breast. Therefore, breast cancer develops in an adipose-rich environment. During obesity, changes in the local environment in the breast occur which are associated with breast cancer. A shift towards a pro-inflammatory state is seen, resulting in altered levels of cytokines and immune cells. Levels of adipokines, such as leptin, adiponectin, and resistin, are changed. Aromatase activity rises, resulting in higher levels of potent estrogen in the breast. Lastly, remodeling of the extracellular matrix takes place. In this review, we address the current knowledge on the changes in the breast adipose tissue in obesity associated with breast cancer initiation and progression. We aim to identify obesity-associated biomarkers in the breast involved in the interplay between obesity and breast cancer. Hereby, we can improve identification of women with obesity with an increased risk of breast cancer and an impaired prognosis. Studies investigating mammary adipocytes and breast adipose tissue in women with obesity versus women without obesity are, however, sparse and further research is needed.

Association of circulating leptin, adiponectin, and resistin concentrations with long-term breast cancer prognosis in a German patient cohort

Adipokines including leptin, adiponectin and resistin have been linked to risk of obesity-related cancers potentially through low-grade chronic inflammation pathways. We aimed to assess the role of post-diagnosis circulating adipokines on long-term prognosis in a prospective breast cancer cohort. Adipokines were measured in blood collected at baseline shortly after diagnosis (2002-2005) and at follow-up (2009) from 3112 breast cancer patients enrolled in the population-based MARIE study. Half of the patients had measurements at both time-points. All-cause mortality, breast cancer specific mortality and recurrences were ascertained up to June 2015 (11 years median follow-up). Associations with time-varying adipokine concentrations overall and stratified by estrogen and progesterone receptor (ERPR) were evaluated using adjusted proportional hazard regression. At baseline (n = 2700) and follow-up (n = 2027), median concentrations for leptin, adiponectin and resistin were 4.6 and 2.7 ng/ml, 24.4 and 30.0 mg/l, 15.4 and 26.2 ng/ml, respectively. After adjustment, there was no evidence for associations between adipokines and any outcome overall. In ERPR negative tumors, highest vs. lowest quintile of adiponectin was significantly associated with increased breast cancer specific mortality (HR 2.51, 95%CI 1.07-5.92). Overall, post-diagnosis adipokines were not associated with long-term outcomes after breast cancer. In patients with ERPR negative tumors, higher concentrations of adiponectin may be associated with increased breast cancer specific mortality and warrant further investigation.

Help or hindrance: The obesity paradox in cancer treatment response

Obesity is a rising epidemic, the influence of which on cancer development, progression as well as its impact on current standard of care cancer treatments is profound with many facets. Obesity is emerging as a modulating factor in many cancer therapies, such as chemotherapy, radiotherapy, immunotherapy and combination therapies. It has been reported to diminish the efficacy of some treatments but has also been alluded to being protective in terms of reduced treatment toxicities, thus the evolution of the obesity paradox. The obese tumour microenvironment influences treatment response through modulation of a series of aspects, including altered adipocyte secretome, angiogenesis, hypoxia, fibrosis, free fatty acid uptake as well as a modulated immune landscape. However, the influence of these underlying mechanisms on cancer treatment response and the biological action of adipose tissue is still largely unknown. Elucidation of these facets may lead to the enhanced efficacy of current treatment options or the identification of novel methods to combat cancer in the obese tumour microenvironment.

The paracrine effects of adipocytes on lipid metabolism in doxorubicin-treated triple negative breast cancer cells

Adipocytes in the breast tumour microenvironment promotes acquired treatment resistance. We used an in vitro adipocyte-conditioned media approach to investigate the direct paracrine effects of adipocyte secretory factors on MDA-MB-231 breast cancer cells treated with doxorubicin to clarify the underlying treatment resistance mechanisms. Cell-viability assays, and Western blots were performed to determine alterations in apoptotic, proliferation and lipid metabolism protein markers. Free fatty acids (FFA) and inflammatory markers in the collected treatment-conditioned media were also quantified. Adipocyte secretory factors increased the cell-viability of doxorubicin-treated cells (p < 0.0001), which did not correspond to apoptosis or proliferation pathways. Adipocyte secretory factors increased the protein expression of hormone-sensitive lipase (p < 0.05) in doxorubicin-treated cells. Adipocyte secretory factors increased the utilization of leptin (p < 0.05) and MCP-1 (p < 0.01) proteins and possibly inhibited release of linoleic acid by doxorubicin-treated cells (treatment-conditioned media FFA profiles). Adipocyte secretory factors induced doxorubicin treatment resistance, by increasing the utilization of inflammatory mediators and inhibiting the release of FFA by doxorubicin-treated cells. This further promotes inflammation and lipid metabolic reprogramming (lipid storage) in the tumour microenvironment, which breast cancer cells use to evade the toxic effects induced by doxorubicin and confers to acquired treatment resistance.

Insulin Resistance and Cancer: In Search for a Causal Link

Insulin resistance (IR) is a condition which refers to individuals whose cells and tissues become insensitive to the peptide hormone, insulin. Over the recent years, a wealth of data has made it clear that a synergistic relationship exists between IR, type 2 diabetes mellitus, and cancer. Although the underlying mechanism(s) for this association remain unclear, it is well established that hyperinsulinemia, a hallmark of IR, may play a role in tumorigenesis. On the other hand, IR is strongly associated with visceral adiposity dysfunction and systemic inflammation, two conditions which favor the establishment of a pro-tumorigenic environment. Similarly, epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA, in IR states, have been often associated with tumorigenesis in numerous types of human cancer. In addition to these observations, it is also broadly accepted that gut microbiota may play an intriguing role in the development of IR-related diseases, including type 2 diabetes and cancer, whereas potential chemopreventive properties have been attributed to some of the most commonly used antidiabetic medications. Herein we provide a concise overview of the most recent literature in this field and discuss how different but interrelated molecular pathways may impact on tumor development.

Reduced tissue and serum resistin expression as a clinical marker for esophageal squamous cell carcinoma

Esophageal cancer is one of the most common malignancies and leading cause of cancer-associated mortality worldwide. However, the molecular mechanisms underlying esophageal cancer progression and the development of clinical tools for effective diagnosis remain unclear. Resistin, which was originally identified as an adipose tissue-secretory factor, has been associated with obesity-related diseases, including certain types of cancer. Thus, the present study aimed to investigate the expression levels of resistin in tissue and serum specimens from patients with esophageal squamous cell carcinoma (ESCC) to determine the potential biological effects of resistin on ESCC cells. The results demonstrated that both tissue and serum resistin levels were significantly lower in patients with ESCC compared with healthy controls. In addition, resistin expression was positively associated with the body mass index of patients with ESCC. In vitro studies revealed that resistin inhibited the migratory ability of ESCC cells, while having no effect on ESCC cell proliferation. Taken together, these results suggest that resistin may have the potential to be developed into a clinical marker for ESCC. However, further studies are required to investigate resistin receptor expression and determine the potential involvement of resistin-associated biological pathways, which may provide insight for future development of targeted therapies for resistin-mediated ESCC.

Endocrine regulation of cancer stem cell compartments in breast tumors

Cancer cells within breast tumors exist within a hierarchy in which only a small and rare subset of cells is able to regenerate growths with the heterogeneity of the original tumor. These highly malignant cancer cells, which behave like stem cells for new cancers and are called "cancer stem cells" or CSCs, have also been shown to possess increased resistance to therapeutics, and represent the root cause underlying therapy failures, persistence of residual disease, and relapse. As >90% of cancer deaths are due to refractory tumors, identification of critical molecular drivers of the CSC-state would reveal vulnerabilities that can be leveraged in designing therapeutics that eradicate advanced disease and improve patient survival outcomes. An expanding and complex body of work has now described the exquisite susceptibility of CSC pools to the regulatory influences of local and systemic hormones. Indeed, breast CSCs express a plethora of hormonal receptors, which funnel hormonal influences over every aspect of breast neoplasia - be it tumor onset, growth, survival, invasion, metastasis, or therapy resistance - via directly impacting CSC behavior. This article is intended to shed light on this active area of investigation by attempting to provide a systematic and comprehensive overview of the available evidence directly linking hormones to breast CSC biology.

Targeting Adipokines in Obesity-Related Tumors

Obesity, a global epidemic, is an independent risk factor for the occurrence and development of a variety of tumors, such as breast cancer, pancreatic cancer, ovarian cancer and colorectal cancer. Adipocytes are important endocrine cells in the tumor microenvironment of obesity-related tumors, which can secrete a variety of adipokines (such as leptin, adiponectin, estrogen, resistin, MIF and MCP-1, etc.), among which leptin, adiponectin and estrogen are the most in-depth and valuable ones. These adipokines are closely related to tumorigenesis and the progression of tumors. In recent years, more and more studies have shown that under chronic inflammatory conditions such as obesity, adipocytes secrete more adipokines to promote the tumorigenesis and development of tumors. However, it is worth noting that although adiponectin is also secreted by adipocytes, it has an anti-tumor effect, and can cross-talk with other adipokines (such as leptin and estrogen) and insulin to play an anti-tumor effect together. In addition, obesity is the main cause of insulin resistance, which can lead to the increase of the expression levels of insulin and insulin-like growth factor (IGF). As important regulators of blood glucose and lipid metabolism, insulin and IGF also play an important role in the progress of obesity related tumors. In view of the important role of adipokines secreted by adipocytes and insulin/IGF in tumors, this article not only elaborates leptin, adiponectin and estrogen secreted by adipocytes and their mechanism of action in the development of obesity- related tumors, but also introduces the relationship between insulin/IGF, a regulator of lipid metabolism, and obesity related tumors. At the same time, it briefly describes the cancer-promoting mechanism of resistin, MIF and MCP-1 in obesity-related tumors, and finally summarizes the specific treatment opinions and measures for various adipokines and insulin/insulin-like growth factors in recent years.

Targeting obesity-related dysfunction in hormonally driven cancers

Obesity is a risk factor for at least 13 different types of cancer, many of which are hormonally driven, and is associated with increased cancer incidence and morbidity. Adult obesity rates are steadily increasing and a subsequent increase in cancer burden is anticipated. Obesity-related dysfunction can contribute to cancer pathogenesis and treatment resistance through various mechanisms, including those mediated by insulin, leptin, adipokine, and aromatase signalling pathways, particularly in women. Furthermore, adiposity-related changes can influence tumour vascularity and inflammation in the tumour microenvironment, which can support tumour development and growth. Trials investigating non-pharmacological approaches to target the mechanisms driving obesity-mediated cancer pathogenesis are emerging and are necessary to better appreciate the interplay between malignancy, adiposity, diet and exercise. Diet, exercise and bariatric surgery are potential strategies to reverse the cancer-promoting effects of obesity; trials of these interventions should be conducted in a scientifically rigorous manner with dose escalation and appropriate selection of tumour phenotypes and have cancer-related clinical and mechanistic endpoints. We are only beginning to understand the mechanisms by which obesity effects cell signalling and systemic factors that contribute to oncogenesis. As the rates of obesity and cancer increase, we must promote the development of non-pharmacological lifestyle trials for the treatment and prevention of malignancy.

LPS/TLR4 pathways in breast cancer: insights into cell signalling

BACKGROUND

Cancer cells are usually recognized as foreign particles by the immune cells. Mounting evidences suggest important link between toll like receptors (TLRs) and carcinogenesis. This review article focused on the role of TLRs, especially TLR4 in breast cancer. <p> Methods: Research data on TLRs and cancer was explored in PubMed, Scopus, Google Scholar, and reviewed. Although some pioneer works are referenced, papers published in last ten years were mostly cited. <p> Results: TLRs are widely investigated pattern recognition receptors (PRR), and TLR4 is the most studied TLRs, implicated with occurrence of several types of cancers including breast cancer. TLR4 activation occurs via the binding of its ligand lipopolysaccharide (LPS), a component of the outer membrane of gram negative bacteria. Upon LPS binding, TLR4 dimerizes and recruits downstream signalling and/or adapter molecules leading to gene expression related to cancer cell proliferation, survival, invasion, and metastasis. Although LPS/TLR4 signalling seems a single signal transduction pathway, the TLR4 activation results in the activation of multiple diverse intracellular networks with huge cellular responses in both immune and cancer cells. The role of TLR4 in growth, invasion and metastasis of breast cancer is attracting huge attention in oncology research. Several clinical and preclinical studies utilize both TLR4 agonists and antagonists as treatment option for cancer therapy either as monotherapy or adjuvants for vaccine development. <p> Conclusion: This review narrates the role of LPS/TLR4 signalling in breast cancer development and future prospective for targeting LPS/TLR4 axis in the treatment of breast cancer.

Is resistin the master link between inflammation and inflammation-related chronic diseases?

Resistin has been firstly discovered in mice and was identified as an adipose tissue-secreted hormone or adipokine linking obesity and insulin resistance. In humans, resistin has been characterized as a hormone expressed and secreted by Immune cells especially by macrophages, and was linked to many inflammatory responses including inflammation of adipose tissue due to macrophages' infiltration. Human and mouse resistin display sequence and structural similarities and also dissimilarities that could explain their different expression pattern. In mice, strong pieces of evidence clearly associated high resistin plasma levels to obesity and insulin resistance suggesting that resistin could play an important role in the onset and progression of obesity and insulin resistance via resistin-induced inflammation. In humans, the link between resistin and obesity/insulin resistance is still a matter of debate and needs more epidemiological studies. Also, resistin has been linked to other chronic diseases such as cardiovascular diseases and cancers where resistin has been proposed in many studies as a biological marker.

Resistin: A journey from metabolism to cancer

•

Resistin levels have been associated with several pathological disorders such as metabolic disorders, cancers etc.

•

Resistin exists in three isoforms namely RELM-α, β and γ.

•

High resistin level activates inflammatory pathways, promotes metabolic disorders and is associated with carcinogenesis.

•

Increase in the resistin level impairs the therapeutic response by inducing stemness or resistance, in cancer cells.

•

Conventional drugs which alter resistin level could have therapeutic implications in several pathological disorders.

Resistin, a small secretory molecule, has been implicated to play an important role in the development of insulin resistance under obese condition. For the past few decades, it has been linked to various cellular and metabolic functions. It has been associated with diseases like metabolic disorders, cardiovascular diseases and cancers. Numerous clinical studies have indicated an increased serum resistin level in pathological disorders which have been reported to increase mortality rate in comparison to low resistin expressing subjects. Various molecular studies suggest resistin plays a pivotal role in proliferation, metastasis, angiogenesis, inflammation as well as in regulating metabolism in cancer cells. Therefore, understanding the role of resistin and elucidating its’ associated molecular mechanism will give a better insight into the management of these disorders. In this article, we summarize the diverse roles of resistin in pathological disorders based on the available literature, clinicopathological data, and a compiled study from various databases. The article mainly provides comprehensive information of its role as a target in different treatment modalities in pre as well as post-clinical studies.

Current Landscape: The Mechanism and Therapeutic Impact of Obesity for Breast Cancer

Obesity is defined as a chronic disease induced by an imbalance of energy homeostasis. Obesity is a widespread health problem with increasing prevalence worldwide. Breast cancer (BC) has already been the most common cancer and one of the leading causes of cancer death in women worldwide. Nowadays, the impact of the rising prevalence of obesity has been recognized as a nonnegligible issue for BC development, outcome, and management. Adipokines, insulin and insulin-like growth factor, sex hormone and the chronic inflammation state play critical roles in the vicious crosstalk between obesity and BC. Furthermore, obesity can affect the efficacy and side effects of multiple therapies such as surgery, radiotherapy, chemotherapy, endocrine therapy, immunotherapy and weight management of BC. In this review, we focus on the current landscape of the mechanisms of obesity in fueling BC and the impact of obesity on diverse therapeutic interventions. An in-depth exploration of the underlying mechanisms linking obesity and BC will improve the efficiency of the existing treatments and even provide novel treatment strategies for BC treatment.

Roles and mechanisms of adipokines in drug resistance of tumor cells

The drug resistance of cancer cells has become one of the biggest obstacles of effective anticancer treatments. Adipocytes produce plenty of cytokines (also known as adipokines), which remarkably affect the drug resistance exhibited by cancer cells. Different adipokines (leptin, visfatin, resistin, adiponectin, Interleukin 6, and tumor necrosis factor α) can induce drug resistance in different cancer cells by various functional mechanisms. This phenomenon is of great interest in pharmacological anti-cancer studies since it indicates that in the cancers with adipocyte-rich microenvironment, all adipokines join together to assist cancer cells to survive by facilitating drug resistance. Studies on adipokines contribute to the development of novel pharmacological strategies for cancer therapy if their roles and molecular targets are better understood. The review will elucidate the roles and the underlying mechanisms of adipokines in drug resistance, which may be of great significance for revealing new strategies for cancer treatment.

HMGB1 is a key factor for tamoxifen resistance and has the potential to predict the efficacy of CDK4/6 inhibitors in breast cancer

Breast cancer is the leading cause of cancer death in women. Hormone‐receptor‐positive breast cancer (HR + BC) is the most common pathological type of breast cancer, of which the main treatment method is endocrine therapy. Unfortunately, primary or acquired drug resistance greatly limits its efficacy. In recent years, the newly launched CDK4/6 inhibitors could effectively reverse endocrine resistance in breast cancer. However, considering their expensive price and side effects, it is particularly important to find out effective biomarkers and screen sensitive patients. Here, we found through bioinformatics analysis that high mobility group box 1 (HMGB1) expression increased in endocrine‐resistant HR + BC. In clinical specimens, the higher expression of HMGB1 was associated with shorter progression‐free survival (PFS) for HR + BC patients with endocrine therapy after surgery. For endocrine‐resistant breast cancer, compared with HMGB1‐negative patients, HMGB1‐positive patients who received CDK4/6 inhibitors treatment benefited more in PFS. Moreover, we demonstrated that HMGB1 promoted tamoxifen resistance by combining with the Toll‐like receptor 4 (TLR4) and activating nuclear factor kappa B (NF‐κB) pathway. CDK4/6 inhibitors could downregulate the expression of HMGB1 and suppress the TLR4‐NF‐κB pathway, and in turn reverse tamoxifen resistance. These results illuminated the critical role of HMGB1 in the process of tamoxifen resistance, explained the mechanism of CDK4/6 inhibitors reversing tamoxifen resistance, and suggested the feasibility of HMGB1 as a potential biomarker for screening sensitive patients receiving CDK4/6 inhibitors.

Biomimetic co-assembled nanodrug of doxorubicin and berberine suppresses chemotherapy-exacerbated breast cancer metastasis

Chemotherapy is a major approach for treating breast cancer patients. Paradoxically, it can also induce cancer progression. Understanding post-chemotherapy metastasis mechanism will help the development of new therapeutic strategies to ameliorate chemotherapy-induced cancer progression. In this study, we deciphered the role of HMGB1 in the regulation of TLR4-mediated epithelial to mesenchymal transitions (EMT) process on doxorubicin (Dox)-treated 4T1 breast cancer cells. Berberine (Ber), a clinically approved alkaloid has been demonstrated as an HMGB1-TLR4 axis regulator to Dox-exacerbated breast cancer metastasis in vitro and in vivo. Hypothesizing that combination of Dox and Ber would be beneficial for breast cancer chemotherapy, we engineered self-assembled nanodrug (DBNP) consisting of Dox and Ber without the aid of additional carriers. After cloaking with 4T1 cell membranes, DBNP@CM exhibited higher accumulation at tumor sites and prolonged blood circulation time in 4T1 orthotopic tumor-bearing mice than DBNP. Importantly, DBNP@CM not only effectively inhibited tumor growth with fewer side effects, but also remarkably suppressed pulmonary metastasis via blocking HMGB1-TLR4 axis. Together, our results have provided a promising combination strategy to dampen chemotherapy-exacerbated breast cancer metastasis and shed light on the development of biomimetic nanodrug for efficient and safe breast cancer chemotherapy.

Molecular insights into the interplay between adiposity, breast cancer and bone metastasis

Cancer is a complex disease, with various pre-existing health ailments enhancing its pathology. In cancer, the extracellular environment contains various intrinsic physiological factors whose levels are altered with aging and pre-existing conditions. In obesity, the tumor microenvironment and metastases are enriched with factors that are both derived locally, and from other physiological compartments. Similarly, in obesity, the cancer cell environment both at the site of origin and at the secondary site i.e., metastatic niche, contains significantly more phenotypically-altered adipocytes than that of un-obese cancer patients. Indeed, obesity has been linked with cancer progression, metastasis, and therapy resistance. Adipocytes not only interact with tumor cells, but also with adjacent stromal cells at primary and metastatic sites. This review emphasizes the importance of bidirectional interactions between adipocytes and breast tumor cells in breast cancer progression and its bone metastases. This paper not only chronicles the role of various adipocyte-derived factors in tumor growth, but also describes the significance of adipocyte-derived bone metastatic factors in the development of bone metastasis of breast cancer. It provides a molecular view of the interplay between the adipocytes and tumor cells involved in breast cancer bone metastasis. However, more research is needed to determine if targeting cancer-associated adipocytes holds promise as a potential therapeutic approach for breast cancer bone metastasis treatment. Interplay between adipocytes and breast cancer cells at primary cancer site and metastatic bone microenvironment. AMSC Adipose-derived mesenchymal stem cell, CAA Cancer associated adipocytes, CAF Cancer associated fibroblast, BMSC Bone marrow derived mesenchymal stem cell, BMA Bone marrow adipocyte.

Tumor Metabolic Reprogramming by Adipokines as a Critical Driver of Obesity-Associated Cancer Progression

Adiposity is associated with an increased risk of various types of carcinoma. One of the plausible mechanisms underlying the tumor-promoting role of obesity is an aberrant secretion of adipokines, a group of hormones secreted from adipose tissue, which have exhibited both oncogenic and tumor-suppressing properties in an adipokine type- and context-dependent manner. Increasing evidence has indicated that these adipose tissue-derived hormones differentially modulate cancer cell-specific metabolism. Some adipokines, such as leptin, resistin, and visfatin, which are overproduced in obesity and widely implicated in different stages of cancer, promote cellular glucose and lipid metabolism. Conversely, adiponectin, an adipokine possessing potent anti-tumor activities, is linked to a more favorable metabolic phenotype. Adipokines may also play a pivotal role under the reciprocal regulation of metabolic rewiring of cancer cells in tumor microenvironment. Given the fact that metabolic reprogramming is one of the major hallmarks of cancer, understanding the modulatory effects of adipokines on alterations in cancer cell metabolism would provide insight into the crosstalk between obesity, adipokines, and tumorigenesis. In this review, we summarize recent insights into putative roles of adipokines as mediators of cellular metabolic rewiring in obesity-associated tumors, which plays a crucial role in determining the fate of tumor cells.

The Tumor Microenvironment as a Driving Force of Breast Cancer Stem Cell Plasticity

Simple Summary

Breast cancer stem cells are a subset of transformed cells that sustain tumor growth and can metastasize to secondary organs. Since metastasis accounts for most cancer deaths, it is of paramount importance to understand the cellular and molecular mechanisms that regulate this subgroup of cells. The tumor microenvironment (TME) is the habitat in which transformed cells evolve, and it is composed by many different cell types and the extracellular matrix (ECM). A body of evidence strongly indicates that microenvironmental cues modulate stemness in breast cancer, and that the coevolution of the TME and cancer stem cells determine the fate of breast tumors. In this review, we summarize the studies providing links between the TME and the breast cancer stem cell phenotype and we discuss their specific interactions with immune cell subsets, stromal cells, and the ECM.

Abstract

Tumor progression involves the co-evolution of transformed cells and the milieu in which they live and expand. Breast cancer stem cells (BCSCs) are a specialized subset of cells that sustain tumor growth and drive metastatic colonization. However, the cellular hierarchy in breast tumors is rather plastic, and the capacity to transition from one cell state to another depends not only on the intrinsic properties of transformed cells, but also on the interplay with their niches. It has become evident that the tumor microenvironment (TME) is a major player in regulating the BCSC phenotype and metastasis. The complexity of the TME is reflected in its number of players and in the interactions that they establish with each other. Multiple types of immune cells, stromal cells, and the extracellular matrix (ECM) form an intricate communication network with cancer cells, exert a highly selective pressure on the tumor, and provide supportive niches for BCSC expansion. A better understanding of the mechanisms regulating these interactions is crucial to develop strategies aimed at interfering with key BCSC niche factors, which may help reducing tumor heterogeneity and impair metastasis.

Molecular mechanisms and the vital roles of resistin, TLR 4, and NF-κB in treating type 2 diabetic complications

Background

Type 2 diabetes in obese (≥ 25 and ≥ 30 kg/m2) patients is the foremost cause of cardiovascular complications like stroke, osteoarthritis, cancers (endometrial, breast, ovarian, liver, kidney, colon, and prostate), and vascular complications like diabetic neuropathy, diabetic and retinopathy, and diabetic nephropathy. It is recognized as a global burden disorder with high prevalence in middle-income nations which might lead to a double burden on health care professionals. Hence, this review emphasizes on understanding the complexity and vital signaling tracts involved in diabetic complications for effective treatment.

Main body

Type 2 diabetes in overweight patients induces the creation of specific ROS that further leads to changes in cellular proliferation, hypothalamus, and fringe. The resistin, TLR4, and NF-κB signalings are mainly involved in the progression of central and fringe changes such as insulin resistance and inflammation in diabetic patients. The overexpression of these signals might lead to the rapid progression of diabetic vascular complications induced by the release of proinflammatory cytokines, chemokines, interleukins, and cyclooxygenase-mediated chemicals. Until now, there has been no curative treatment for diabetes. Therefore, to effectively treat complications of type 2 diabetes, the researchers need to concentrate on the molecular mechanisms and important signaling tracts involved.

Conclusion

In this review, we suggested the molecular mechanism of STZ-HFD induced type 2 diabetes and the vital roles of resistin, TLR4, and NF-κB signalings in central, fringe changes, and development diabetic complications for its effective treatment.

Graphical abstract

Adipocytes promote breast tumorigenesis through TAZ-dependent secretion of Resistin

Adipocytes are the most abundant and perhaps most active components of the tumor microenvironment in obese individuals that potentiate breast tumorigenesis through secretory mechanisms. The modulation of adipocytes can be novel therapy targets for breast cancer. Here, we revealed a specific upregulation of adipocytic TAZ through the FFA/PPARγ axis in diet-induced adiposity. Adipocytic TAZ knockdown or deficiency in mice inhibits adipocyte-induced breast cancer proliferation and stemness through impaired expression and secretion of Resistin. Immunostaining in triple-negative breast cancer samples showed that higher adipocytic TAZ/Resistin expression associates with higher clinical stages and poorer survival, demonstrating promising therapeutic targets.

Adipocytes have been implicated in breast tumor growth and stemness maintenance through secreted factors. However, the mechanisms by which these cytokines are regulated during diet-induced obesity and contribute to breast tumorigenesis remain largely unknown. Here we show that transcription cofactor TAZ in adipocytes is directly up-regulated by the free fatty acid/PPARγ axis upon dietary fat stimulation. TAZ knockdown alters the expression profile of a series of secreted proteins and attenuates the tumor-supporting function of adipocytes. Moreover, we identify Resistin, an adipose-derived hormone, as a functional downstream target of TAZ, which facilitates tumorigenesis, and its expression correlated with adipocyitc TAZ in triple-negative breast cancer samples. Further, Adiponectin-cre–mediated TAZ knockout in adipocytes mitigates breast tumor growth. Taken together, our findings highlight how diet-induced TAZ expression in adipocytes promotes tumorigenesis, suggesting promising cancer therapeutic targets.