Circulating High-Molecular-Weight (HMW) Adiponectin Level Is Related with Breast Cancer Risk Better than Total Adiponectin: A Case-Control Study

Beyond Body Size: Adiponectin as a Key Player in Obesity-Driven Cancers

Obesity, a complex and multifactorial disease influenced by genetic, environmental, and psychological factors, has reached epidemic proportions globally, posing a significant health challenge. In addition to its established association with cardiovascular disease and type II diabetes, obesity has been implicated as a risk factor for various cancers. However, the precise biological mechanisms linking obesity and cancer remain largely understood. Adipose tissue, an active endocrine organ, produces numerous hormones and bioactive molecules known as adipokines, which play a crucial role in metabolism, immune responses, and systemic inflammation. Notably, adiponectin (APN), the principal adipocyte secretory protein, exhibits reduced expression levels in obesity. In this scoping review, we explore and discuss the role of APN in influencing cancer in common malignancies, including lung, breast, colorectal, prostate, gastric, and endometrial cancers. Our review aims to emphasize the critical significance of investigating this field, as it holds great potential for the development of innovative treatment strategies that specifically target obesity-related malignancies. Furthermore, the implementation of more rigorous and comprehensive prevention and treatment policies for obesity is imperative in order to effectively mitigate the risk of associated diseases, such as cancer.

Novel insights into adiponectin action in breast cancer: Evidence of its mechanistic effects mediated by ERα expression

This review describes the multifaceted effects of adiponectin on breast cancer cell signalling, tumour metabolism, and microenvironment. It is largely documented that low adiponectin levels are associated with an increased risk of breast cancer. However, it needs to be still clarified what are the extents of the decrease of local/intra-tumoural adiponectin concentrations, which promote breast tumour malignancy. Most of the anti-proliferative and pro-apoptotic effects induced by adiponectin have been obtained in breast cancer cells not expressing estrogen receptor alpha (ERα). Here, we will highlight recent findings demonstrating the mechanistic effects through which adiponectin is able to fuel genomic and non-genomic estrogen signalling, inhibiting LKB1/AMPK/mTOR/S6K pathway and switching energy balance. Therefore, it emerges that the reduced adiponectin levels in patients with obesity work to sustain tumour growth and progression in ERα-positive breast cancer cells. All this may contribute to remove the misleading paradigm that adiponectin univocally inhibits breast cancer cell growth and progression independently on ERα status. The latter concept, here clearly provided by pre-clinical studies, may have translational relevance adopting adiponectin as a potential therapeutic tool. Indeed, the interfering role of ERα on adiponectin action addresses how a separate assessment of adiponectin treatment needs to be considered in novel therapeutic strategies for ERα-positive and ERα-negative breast cancer.

Glitazone loaded fat enhances adiponectin production and inhibits breast cancer cell proliferation

Obesity and diabetes are both associated risk factors for developing breast cancer and poor patient outcomes. Adipose cells are an important endocrine system and are the main producer of adiponectin, with lean patients having higher circulating levels. Patients with diabetes are often treated with thiazolidinediones, glitazones, which also increase adiponectin production. Importantly high circulating levels of adiponectin and treatment with glitazone are associated with increased breast cancer patient survival. This study investigates the potential of using adipose tissue laden with glitazones to act as a drug depot, increase adiponectin levels, and locally release glitazones to inhibit breast cancer cell proliferation. The breast cancer cell lines MCF-7 and MBA-MD-231, and the normal breast epithelial cell line MCF-10A were exposed to media containing a range of concentrations of recombinant adiponectin, pioglitazone, or conditioned media obtained from pioglitazone laden adipose tissue to determine the impact of the different treatments on cell proliferation. The MCF-7 cells demonstrated the greatest reduction in proliferation upon exposure to adiponectin and pioglitazone with lower reductions observed in the MDA-MD-231 and MCF-10a cell lines. All three cell lines exhibited reductions in proliferation in the presence of pioglitazone loaded adipose tissue. Additionally, adiponectin and pioglitazone levels were higher in the media from glitazone loaded adipose tissue. Drug loaded adipose tissue could potentially be used to deliver adiponectin and glitazone to breast cancer cells and inhibit proliferation. Future research will examine the potential efficacy of this treatment approach in vivo.

Adipose Tissue, Obesity and Adiponectin: Role in Endocrine Cancer Risk

Adipose tissue has been recognized as a complex organ with endocrine and metabolic roles. The excess of fat mass, as occurs during overweight and obesity states, alters the regulation of adipose tissue, contributing to the development of obesity-related disorders. In this regard, many epidemiological studies shown an association between obesity and numerous types of malignancies, comprising those linked to the endocrine system (e.g., breast, endometrial, ovarian, thyroid and prostate cancers). Multiple factors may contribute to this phenomenon, such as hyperinsulinemia, dyslipidemia, oxidative stress, inflammation, abnormal adipokines secretion and metabolism. Among adipokines, growing interest has been placed in recent years on adiponectin (APN) and on its role in carcinogenesis. APN is secreted by adipose tissue and exerts both anti-inflammatory and anti-proliferative actions. It has been demonstrated that APN is drastically decreased in obese individuals and that it can play a crucial role in tumor growth. Although literature data on the impact of APN on carcinogenesis are sometimes conflicting, the most accredited hypothesis is that it has a protective action, preventing cancer development and progression. The aim of the present review is to summarize the currently available evidence on the involvement of APN and its signaling in the etiology of cancer, focusing on endocrine malignancies.

Association of serum adiponectin with breast cancer: A meta-analysis of 27 case-control studies

BACKGROUND

Emerging published studies have indicated that adiponectin is involved in tumorigenesis of breast cancer. However, the results of available studies were inconsistent. The aim of this updated meta-analysis was to assess the association of adiponectin with breast cancer.

MATERIALS AND METHODS

PubMed, EMBASE, Wanfang databases, and the China National Knowledge Infrastructure (CNKI) were systematically searched from inception to June 2018. The mean difference (MD) with 95% confidence interval (CI) were estimated and pooled to investigate the effect sizes.

RESULTS

Twenty-seven eligible articles that met the study criteria were included in the current meta-analysis. Overall, there was an evident inverse association between serum adiponectin levels and breast cancer (MD = -0.29, 95%CI = (-0.38, -0.21), P < .001). Asian subgroup showed a significant negative association between serum adiponectin concentrations and breast cancer in subgroup analysis by ethnicity (MD = -2.19, 95%CI = (-3.45, -0.94), P < .001). However, no statistical significance was found in Caucasian subgroup (MD = -0.65, 95%CI = (-1.47, 0.17), P = 0.12). Additionally, a further subgroup analysis of Asian stratified by menopausal status showed higher concentrations of adiponectin in healthy control group, whether they were premenopausal (MD = -0.85, 95%CI = (-1.50, -0.19), P = .01) or postmenopausal (MD = -2.17, 95%CI = (-4.17, -0.18), P = .03). No significant difference was observed concerning the association between serum adiponectin and breast cancer metastasis (MD = -1.56, 95%CI = (-4.90, 1.78), P = .36).

CONCLUSION

The current meta-analysis suggests that the serum adiponectin may be inversely associated with breast cancer. Decreased serum adiponectin levels in premenopausal women may also be inversely associated with breast cancer risk other than postmenopausal status. In addition, low serum adiponectin levels in Asian women were more likely to be associated with breast cancer risk than Caucasian women.

Metabolic Syndrome, and Particularly the Hypertriglyceridemic-Waist Phenotype, Increases Breast Cancer Risk, and Adiponectin Is a Potential Mechanism: A Case-Control Study in Chinese Women

Objective: To investigate the association between metabolic syndrome and breast cancer and to elucidate the potential mechanism underlying this association. Patients and Methods: Based on baseline data drawn from 21 hospitals in 11 provinces of China, we performed a case-control study among 1,127 women (595 cases and 532 controls), divided into premenopausal, and postmenopausal subgroups. Student's t test, Pearson's χ² test, and logistic regression analyses were performed to ascertain the association between breast cancer and metabolic syndrome, including all of its components. In addition, we attempted to clarify the potential role of adiponectin in this association. Results: Among the components of metabolic syndrome, abnormal waist circumference was the component that markedly increased breast cancer risk in premenopausal women (OR 1.447, 95% CI 1.043-2.006). Metabolic syndrome with clusters of special risk factors showed an association with breast cancer risk. Among all these components of metabolic syndrome, the hypertriglyceridemic-waist (HW) phenotype significantly increased breast cancer risk (OR 1.56, 95% CI 1.02-2.39), regardless of menopausal status, rendering it a strong predictor of breast cancer. Total adiponectin levels and high-molecular-weight adiponectin were reversely associated with metabolic syndrome. In addition, total adiponectin levels among breast cancer patients were much lower than among controls (6.67 ± 3.05 vs. 8.01 ± 4.18, p = 0.014) only in the HW phenotype subgroup. Furthermore, the HW phenotype was associated with increased risk of estrogen receptor/progesterone receptor-positive (ER+/PR+) and -negative (ER-/PR-) breast cancer, with a 51% (OR 1.51, 95% CI 1.03-2.21) and 69% (OR 1.69, 95% CI 1.05-2.72) increase, respectively. However, there was no significant association between the HW phenotype and the ER+/PR- subtype. These results suggested that low adiponectin levels may be a mechanism that explains the association between the HW phenotype and breast cancer risk. Conclusion: Metabolic syndrome with special cluster factors is related to breast cancer risk; in particular, the HW phenotype can be regarded as a strong predictor of breast cancer. As an important factor involved in fat metabolism, adiponectin may strongly predict metabolic syndrome, especially the HW phenotype and breast cancer. Further research into this mechanism and epidemiological studies are needed. This study provides new evidence for the role of a healthy lifestyle in preventing breast cancer.

Serum adiponectin in breast cancer: A meta-analysis

BACKGROUND

Accumulating data have found that adiponectin is involved in development of breast cancer (BC). However, these results were inconsistent.

METHOD

A systematic search in PubMed, Embase, ISI Web of Science, and Chinese National Knowledge Infrastructure databases were conducted up to October 1, 2017. The standardized mean difference (SMD) with 95% confidence interval was applied to pool the effect size.

RESULTS

Finally, 31 eligible studies were included in this meta-analysis. The overall results indicated that serum adiponectin levels in BC cases were significantly lower than the controls (SMD = -0.33, P < 0.0001). As for the subgroup analysis of menstrual status, serum adiponectin levels were significantly lower in pre- and postmenopausal BC cases. Moreover, the subgroup analysis by ethnicity in pre- and postmenopausal group indicated an inverse association between adiponectin levels and BC risk in Asian population, but not in Caucasian population.

CONCLUSION

The present meta-analysis suggests that low serum adiponectin concentration may be associated with an increased BC risk in premenopausal and postmenopausal women, especially among Asians. Adiponectin may serve as a biomarker of BC risk and help to identify subjects at high risk for BC development.

The prognostic value of serum and bronchoalveolar lavage levels of adiponectin in advanced non-small-cell lung cancer

Aim

We aimed to explore the prognostic implications of adiponectin (APN) levels in the serum and bronchoalveolar lavage (BAL) of patients with advanced NSCLC.

Materials & methods

29 newly diagnosed patients with stage IV NSCLC were prospectively enrolled. Baseline serum and BAL levels of APN were assayed by ELISA and correlated with various clinicopathological parameters, including overall survival.

Results

No statistically significant correlations were observed between the serum or BAL levels of APN and the clinicopathological parameters evaluated. The only prognostic factor identified, both by univariate and multivariate survival analyses, was performance status.

Conclusion

The results of our cohort failed to reveal any prognostic significance of serum and BAL levels of APN in stage IV NSCLC.

Effect of reduced dietary fat on estradiol, adiponectin, and IGF-1 levels in postmenopausal women with breast cancer

Introduction

In recent years, epidemiological studies have strongly related obesity with an increased risk of developing postmenopausal breast cancer. The aromatization of fatty tissue increases the levels of estradiol and adiponectin, which is correlated with the body mass index (BMI). It is of interest to investigate the effect of reducing BMI on estradiol, adiponectin, and IGF-1, as reducing BMI could be a new strategy to limit the risk of recurrence during the adjuvant treatment of breast cancer.

Objective

The aim of this study is to investigate the effect of reduced dietary fat on the levels of serum estradiol, adiponectin, and IGF-1 among postmenopausal Mexican women with breast cancer.

Methods

In this controlled clinical trial, 100 female patients were randomly divided into two groups and followed for six months. Group 1 (n = 50) was subjected to reduced dietary fat, whereas Group 2 (n = 50) was subjected to a control diet. The levels of serum estradiol and testosterone were determined using an enzyme-linked immunosorbent assay, whereas the concentrations of adiponectin and IGF-1 were determined using a radioimmunoassay.

Results

The patients subjected to reduced dietary fat showed a significant difference in BMI (27.93 ± 4.45 vs 26.05 ± 2.65; p = 0.01) and waist circumference (99.92 vs 91.59 cm; p = 0.0001) after the treatment. Moreover, a significant decrease in serum estradiol was observed (21.23 ± 14.32 vs 16.05 ± 10.25 ng/mL; p < 0.001). The adiponectin concentration also decreased significantly (47.53 ± 12.19 vs 42.52 ± 12.34 µg/mL; p = 0.004), while IGF-1 and testosterone did not show significant changes (p > 0.05). In addition, BMI had a relationship with serum adiponectin (r = −0.27; p = 0.02) and estradiol (r = 0.37; p = 0.001).

Conclusion

The current study shows that reducing BMI decreases serum estradiol and adiponectin. Large clinical trials are needed to investigate the role of adiponectin in breast cancer development in obese women.

The Association Between Body Size and Breast Cancer in Han Women in Northern and Eastern China

INTRODUCTION

Although obesity has been reported worldwide as a risk factor for breast cancer, there are still some inconsistencies regarding the association between obesity and breast cancer. Body mass index (BMI) is used most to assess the extent of obesity; however, the association of other body size characteristics, such as waist and hip circumference, with susceptibility to breast cancer in Chinese Han women needs to be better assessed.

PATIENTS AND METHODS

Female Chinese Han patients (N = 2,800) were recruited from 21 hospitals in northern and eastern China from April 2012 to April 2013 for a case-control study. The significant differences of factors related to body size between the breast-cancer case and control groups were determined by Student's t test and chi-square tests.

RESULTS

Premenopausal women with breast cancer had higher BMI and larger waist and hip circumferences (p = 2 × 10-4, <1 × 10-6, and 2 × 10-5, respectively). However, these body-size factors were not associated with postmenopausal breast cancer (p = .45, 0.32, and 0.12, respectively). BMI between 28 and 30 kg/m2 or greater than 32 kg/m2 was related to breast cancer incidence in the overall study population and in premenopausal women but not in the postmenopausal group.

CONCLUSION

Obesity is significantly associated with breast cancer in Chinese Han premenopausal women but not in postmenopausal women. Thus, it is important to realize that weight control, as well as avoiding abdominal obesity, should be considered as one of the most effective methods of reducing breast cancer risk.

IMPLICATIONS FOR PRACTICE

To better understand the characteristics and risk factors for breast cancer in Han women in northern and eastern China, a case-control study of 2,800 Chinese Han women was conducted. Obesity was significantly associated with breast cancer in Chinese Han premenopausal women but not in postmenopausal women. Consequently, controlling body weight and avoiding abdominal obesity should be considered as one of the most effective methods of reducing breast cancer susceptibility. However, the diversity between this study's finding among Chinese Han women and other data previously reported among European and American populations still needs further investigation.

Different molecular signaling sustaining adiponectin action in breast cancer

Obesity is defined as a chronic and excessive growth of adipose tissue. It is increasingly recognized as an oncogenic factor. Adipose tissue, originally thought as a passive depot for fat metabolism, is now identified as an endocrine organ, secreting a wide array of bioactive molecules known as adipocytokines, which act as key mediators in several obesity-associated diseases. Among these adipocytokines, adiponectin has been proposed as having a key role in the pathogenesis of cardiovascular disease and type 2 diabetes along with other diseases such as obesity-associated malignancies, including breast cancer. New insights into the molecular mechanisms linking adiponectin and mammary tumorigenesis could be useful to identify novel therapeutic approaches to be exploited, particularly in obese women.

Evolving role of adiponectin in cancer-controversies and update

Adiponectin (APN), an adipokine produced by adipocytes, has been shown to have a critical role in the pathogenesis of obesity-associated malignancies. Through its receptor interactions, APN may exert its anti-carcinogenic effects including regulating cell survival, apoptosis and metastasis via a plethora of signalling pathways. Despite the strong evidence supporting this notion, some work may indicate otherwise. Our review addresses all controversies critically. On the whole, hypoadiponectinaemia is associated with increased risk of several malignancies and poor prognosis. In addition, various genetic polymorphisms may predispose individuals to increased risk of obesity-associated malignancies. We also provide an updated summary on therapeutic interventions to increase APN levels that are of key interest in this field. To date efforts to manipulate APN levels have been promising, but much work remains to be done.