Role of hepatocyte growth factor in breast cancer: a novel mitogenic factor secreted by adipocytes

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.

Targeting MET amplification in Gastro-oesophageal (GO) malignancies and overcoming MET inhibitor resistance: challenges and opportunities

INTRODUCTION

MET, the hepatocyte growth factor receptor is amplified in 8% of gastroesophageal (GO) malignancies and associated with poor prognosis. Therapeutic targeting of MET amplification and MET mutations has the potential to improve outcomes for patients with GO cancers (GOC).

AREAS COVERED

The efficacy of MET inhibition (METi) in preclinical studies has yet to translate into meaningful improvements in the treatment paradigm for unselected GOC. MET amplification has been proposed as a superior modality for patient selection; however even if confirmed, frequency and duration of response to METi are limited by rapid activation of primary and secondary resistance pathways. These observations illustrate the challenges inherent in the application of precision oncology predicated on the theory of oncogenic addiction.

EXPERT OPINION

A standardized definition of MET positivity is critical to enhance patient selection. Early successes targeting the METex14 skipping mutation demonstrate the potent therapeutic effects of METi in a clearly molecularly defined cohort. There is robust preclinical rationale and early-phase data supporting exploitation of immune system interaction with MET. Pragmatic investigation of rational therapeutic combinations based on molecular profiling of both primary and metastatic disease sites with sequential circulating tumor DNA analysis can inform successful clinical development of METi agents in GOC.

Fatty Acid Metabolism Reprogramming in Advanced Prostate Cancer

Prostate cancer (PCa) is a carcinoma in which fatty acids are abundant. Fatty acid metabolism is rewired during PCa development. Although PCa can be treated with hormone therapy, after prolonged treatment, castration-resistant prostate cancer can develop and can lead to increased mortality. Changes to fatty acid metabolism occur systemically and locally in prostate cancer patients, and understanding these changes may lead to individualized treatments, especially in advanced, castration-resistant prostate cancers. The fatty acid metabolic changes are not merely reflective of oncogenic activity, but in many cases, these represent a critical factor in cancer initiation and development. In this review, we analyzed the literature regarding systemic changes to fatty acid metabolism in PCa patients and how these changes relate to obesity, diet, circulating metabolites, and peri-prostatic adipose tissue. We also analyzed cellular fatty acid metabolism in prostate cancer, including fatty acid uptake, de novo lipogenesis, fatty acid elongation, and oxidation. This review broadens our view of fatty acid switches in PCa and presents potential candidates for PCa treatment and diagnosis.

Regulation of Energy Metabolism by Receptor Tyrosine Kinase Ligands

Metabolic diseases, such as diabetes, obesity, and fatty liver disease, have now reached epidemic proportions. Receptor tyrosine kinases (RTKs) are a family of cell surface receptors responding to growth factors, hormones, and cytokines to mediate a diverse set of fundamental cellular and metabolic signaling pathways. These ligands signal by endocrine, paracrine, or autocrine means in peripheral organs and in the central nervous system to control cellular and tissue-specific metabolic processes. Interestingly, the expression of many RTKs and their ligands are controlled by changes in metabolic demand, for example, during starvation, feeding, or obesity. In addition, studies of RTKs and their ligands in regulating energy homeostasis have revealed unexpected diversity in the mechanisms of action and their specific metabolic functions. Our current understanding of the molecular, biochemical and genetic control of energy homeostasis by the endocrine RTK ligands insulin, FGF21 and FGF19 are now relatively well understood. In addition to these classical endocrine signals, non-endocrine ligands can govern local energy regulation, and the intriguing crosstalk between the RTK family and the TGFβ receptor family demonstrates a signaling network that diversifies metabolic process between tissues. Thus, there is a need to increase our molecular and mechanistic understanding of signal diversification of RTK actions in metabolic disease. Here we review the known and emerging molecular mechanisms of RTK signaling that regulate systemic glucose and lipid metabolism, as well as highlighting unexpected roles of non-classical RTK ligands that crosstalk with other receptor pathways.

The use of autologous fat grafts in breast surgery: A literature review

Autologous fat injection was first described roughly a century ago and has been used in surgery ever since. In addition to its use in many surgical fields, it is also frequently used for both aesthetic and reconstructive purposes in breast surgery. Since the application of fat grafting in breast surgery has steadily increased, studies investigating its reliability have simultaneously become increasingly common. Previous studies have reported that the use of fat grafting in breast surgery is reliable, but some pending questions remain about its routine use. In order to use fat grafts successfully in breast surgery, it is necessary to be familiar with the structure and content of adipose tissue, the efficacy of adipose stem cell-enriched fat grafts, the oncological safety of fat grafts, and the problems that may occur in the radiological follow-up of patients who undergo fat grafting procedures. In this literature review, we aim to discuss the use of fat grafts in breast surgery by investigating these common problems.

Cooperative Effect of Oncogenic MET and PIK3CA in an HGF-Dominant Environment in Breast Cancer

There is compelling evidence that oncogenic MET and PIK3CA signaling pathways contribute to breast cancer. However, the activity of pharmacologic targeting of either pathway is modest. Mechanisms of resistance to these monotherapies have not been clarified. Currently, commonly used mouse models are inadequate for studying the HGF-MET axis because mouse HGF does not bind human MET. We established human HGF-MET paired mouse models. In this study, we evaluated the cooperative effects of MET and PIK3CA in an environment with involvement of human HGF in vivo Oncogenic MET/PIK3CA synergistically induced aggressive behavior and resistance to each targeted therapy in an HGF-paracrine environment. Combined targeting of MET and PI3K abrogates resistance. Associated cell signaling changes were explored by functional proteomics. Consistently, combined targeting of MET and PI3K inhibited activation of associated oncogenic pathways. We also evaluated the response of tumor cells to HGF stimulation using breast cancer patient-derived xenografts (PDX). HGF stimulation induced significant phosphorylation of MET for all PDX lines detected to varying degrees. However, the levels of phosphorylated MET are not correlated with its expression, suggesting that MET expression level cannot be used as a sole criterion to recruit patients to clinical trials for MET-targeted therapy. Altogether, our data suggest that combined targeting of MET and PI3K could be a potential clinical strategy for breast cancer patients, where phosphorylated MET and PIK3CA mutation status would be biomarkers for selecting patients who are most likely to derive benefit from these cotargeted therapy.

Adipokines as therapeutic targets in breast cancer treatment

INTRODUCTION

Adipocytes, which represent a substantial part of the tumor microenvironment in breast cancer, secrete several adipokines that affect tumorigenesis, cancer progression, metastasis, and treatment resistance via multiple signaling pathways. Areas covered: In this review, we focus on the role of leptin, adiponectin, autotaxin, and interleukin-6 in breast cancer initiation, progression, metastasis, and drug response. Furthermore, we investigated adipokines as potential targets of breast cancer-specific drugs. Expert opinion: Adipokines and adipokine receptors are deregulated in breast cancer. Adipokines play various roles in breast cancer initiation, progression, metastasis, and drug response, hence, adipokine signaling could be an effective drug target. Several clinical trials are in progress to test the efficacy of adipokine targeting agents. However, adipokines also affect metabolic homeostasis; hence, the adverse effects of the targeted drug should be investigated and addressed.

Pink Adipocytes

Adipocytes are lipid-rich parenchymal cells contained in a very plastic organ, whose composition can undergo striking physiologic changes. In standard conditions the organ contains white and brown adipocytes which play opposite roles: lipid storage to meet metabolic requirements and lipid burning for thermogenesis, respectively. During chronic cold exposure, white adipocytes transdifferentiate to brown, to increase thermogenesis, whereas in conditions of chronic positive energy balance brown adipocytes transdifferentiate to white, to increase energy stores. During pregnancy, lactation, and post-lactation, subcutaneous white adipocytes convert to milk-producing glands formed by lipid-rich elements that can be defined as pink adipocytes. Recent fate-mapping data support the conversion of pink to brown adipocytes and the reversible conversion of brown adipocytes to myoepithelial cells of alveoli.

IL-6-mediated cross-talk between human preadipocytes and ductal carcinoma in situ in breast cancer progression

Background

The function of preadipocytes in the progression of early stage breast cancer has not been fully elucidated at the molecular level. To delineate the role of preadipocytes in breast cancer progression, we investigated the cross-talk between human breast ductal carcinoma in situ (DCIS) cells and preadipocytes with both an in vitro culture and xenograft tumor model.

Methods

GFP or RFP was transduced into human DCIS cell line MCF10DCIS.com cells or preadipocytes using lentivirus. Cell sorter was used to separate pure, viable populations of GFP- or RFP-transduced cells. Cell viability and proliferation was assessed by crystal violet assays and cell migration and invasion capability was assayed by the transwell strategy. Gene and protein levels were measured by western blot, RT-PCR and immunostaining. Adipokines and cytokines were quantified using ELISA. Human tumor xenografts in a nude mice model were used. Ultrasound imaging of tumors was performed to evaluate the therapeutic potential of a IL-6 neutralizing antibody.

Results

In the co-culture system with the MCF10DCIS.com and preadipocytes, MCF10DCIS.com proliferation, migration and invasion were enhanced by preadipocytes. Preadipocytes exhibited in an increased IL-6 secretion and cancer-associated fibroblast markers expression, FSP1 and α-SMC in co-culture with MCF10DCIS.com or in MCF10DCIS.com conditioned media, whereas the adipocyte differentiation capacity was suppressed by co-culture with MCF10DCIS.com. A neutralizing antibody of IL-6 or IL-6R suppressed the promotion of MCF10DCIS.com proliferation and migration by co-culture with preadipocytes. In the xenograft tumor model, the tumor growth of MCF10DCIS.com was enhanced by the co-injection of preadipocytes, and the administration of IL-6 neutralizing antibodies resulted in potent effects on tumor inhibition.

Conclusions

Our findings suggest that IL-6-mediated cross-talk between preadipocytes and breast DCIS cells can promote the progression of early stage breast cancer. Therefore, blocking IL-6 signaling might be a potential therapeutic strategy for breast DCIS characterized by pathological IL-6 overproduction.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0867-3) contains supplementary material, which is available to authorized users.

Dietary oleuropein inhibits tumor angiogenesis and lymphangiogenesis in the B16F10 melanoma allograft model: a mechanism for the suppression of high-fat diet-induced solid tumor growth and lymph node metastasis

Previously, we reported that high-fat-diet (HFD)-induced obesity stimulates melanoma progression in the B16F10 allograft model. In this study, we examined whether oleuropein (OL), the most abundant phenolic compound in olives, inhibits HFD-induced melanoma progression. Four-week-old male C57BL/6N mice were fed a HFD-diet with or without OL. After 16 weeks of feeding, B16F10-luc cells were subcutaneously injected and the primary tumor was resected 3 weeks later. OL suppressed HFD-induced solid tumor growth. In the tumor tissues, OL reduced HFD-induced expression of angiogenesis (CD31, VE-cadherin, VEGF-A, and VEGFR2), lymphangiogenesis (LYVE-1, VEGF-C, VEGF-D, and VEGFR3), and hypoxia (HIF-1α and GLUT-1) markers as well as HFD-induced increases in lipid vacuoles and M2 macrophages (MΦs). All animals were euthanized 2.5 weeks after tumor resection. OL suppressed HFD-induced increases in lymph node (LN) metastasis; expression of VEGF-A, VEGF-C, and VEGF-D in the LN; and M2-MΦs and the size of adipocytes in adipose tissues surrounding LNs. Co-culture results revealed that the crosstalk between B16F10s, M2-MΦs, and differentiated 3T3-L1 cells under hypoxic conditions increased the secretion of VEGF-A and -D, which stimulated tube formation and migration of endothelial cells (HUVECs) and lymphatic endothelial cells (LEC), respectively. Additionally, OL directly inhibited the differentiation of 3T3-L1 preadipocytes and tube formation by HUVECs and LECs. The overall results indicated that dietary OL inhibits lipid and M2-MΦ accumulation in HFD-fed mice, which contributes to decreases in VEGF secretion, thereby leading to inhibition of angiogenesis and lymphangiogenesis.

Species-specific control of hepatocyte growth factor expression and production in adipocytes in a differentiation-dependent manner

Hepatocyte growth factor (HGF) is a mesenchymal cell-derived factor that regulates cell growth, cell motility, and morphogenesis. Since there are conflicting reports on HGF-producing cells, we herein examined HGF activity in conditioned medium (CM) of bovine and mouse preadipocytes before and after adipogenic differentiation. CM of bovine adipocytes and mouse preadipocytes induced the morphogenesis of mammary epithelial cells that was inhibited by an NK4 HGF antagonist, whereas CM of bovine preadipocytes and mouse adipocytes did not. HGF mRNA expression was increased by a treatment with dexamethasone and isobutylmethylxanthine in bovine as well as human cells, whereas it was decreased in rodent cells. It was unfortunate that HGF gene promoter activity failed to reflect HGF mRNA expression in these cells. After actinomycin D treatment, expression of HGF mRNA remained stable in pre- and differentiated bovine adipocytes and mouse preadipocytes, whereas rapidly decreased in mouse-differentiated adipocytes. These results indicate that expression and production of HGF are regulated in a species-specific adipogenic differentiation-dependent manner and suggest that the decrease in HGF mRNA in mouse differentiated adipocytes is, at least in part, mediated by differentiation-dependent loss of its stability.

The Role of Hepatocyte Growth Factor (HGF) in Insulin Resistance and Diabetes

In obesity, insulin resistance (IR) and diabetes, there are proteins and hormones that may lead to the discovery of promising biomarkers and treatments for these metabolic disorders. For example, these molecules may impair the insulin signaling pathway or provide protection against IR. Thus, identifying proteins that are upregulated in IR states is relevant to the diagnosis and treatment of the associated disorders. It is becoming clear that hepatocyte growth factor (HGF) is an important component of the pathophysiology of IR, with increased levels in most common IR conditions, including obesity. HGF has a role in the metabolic flux of glucose in different insulin sensitive cell types; plays a key role in β-cell homeostasis; and is capable of modulating the inflammatory response. In this review, we discuss how, and to what extent HGF contributes to IR and diabetes pathophysiology, as well as its role in cancer which is more prevalent in obesity and diabetes. Based on the current literature and knowledge, it is clear that HGF plays a central role in these metabolic disorders. Thus, HGF levels could be employed as a biomarker for disease status/progression, and HGF/c-Met signaling pathway modulators could effectively regulate IR and treat diabetes.

VEGF, the underlying factor for metabolic syndrome; fact or fiction?

Metabolic syndrome (MetS) is currently diagnosed by the co-presence of at least three of the five following abnormalities: abdominal obesity, dysglycaemia, elevated serum triglycerides, low high-density cholesterol (HDL) and finally elevated blood pressure. Metabolic syndrome increases the risk of developing cardiovascular disease and diabetes. This review is on the associations between MetS and vascular endothelial growth factor (VEGF). VEGF induces migration and proliferation of endothelial cells (ECs), increases vascular permeability and has a role in tumor growth, adipose tissue expansion, age-related macular degeneration and diabetic retinopathy. Circulating levels of VEGFs are elevated in obese individuals and it has also been suggested that VEGF is secreted from adipose tissues, especially from intra-abdominal adipose tissue. There is abundant evidence to support that poor glycemic control in diabetic patients is associated with increased plasma VEGF, which in turn may cause hypertension and several vascular complications in diabetic patients. Circulating VEGF levels are increased in children and young adults with type 1 diabetes mellitus and middle-aged diabetic patients with proliferative retinopathy. It has been revealed that plasma VEGF increases in patients with hyperlipidemia and may trigger the development of atherosclerosis. It can be concluded that there is a positive association between VEGF and components of MetS. Because of the importance of this relationship, more investigations are needed in this field.

Progesterone dose-dependently modulates hepatocyte growth factor production in 3T3-L1 mouse preadipocytes

It is well documented that estrogen is predominant inducer of hepatocyte growth factor (HGF) in a variety of cell types. However, the effect of progesterone (P) remains to be elusive. Thus, in the present study, we examined the effect of P and combined effect of P and 17β-estradiol (E2) on HGF expression and production in 3T3-L1 fibroblastic preadipocytes and mature adipocytes, as a model of stromal cells. Northern blot analysis showed that hgf mRNA expressed in preadipocytes was notably higher than that of mature adipocytes, and increased by treatment of preadipocytes with E2 or 10 nM P, but not with 1,000 nM P. The E2-induced hgf mRNA expression was enhanced by 10 nM P, but suppressed by 1,000 nM P. Western blot analysis revealed that biological active forms of HGF protein was found in the preadipocyte culture medium, while the lesser amount of HGF precursor protein was detected in the mature adipocyte culture medium. The amounts of HGF were changed dependently on the hgf mRNA expression levels. These results indicate that HGF production is intricately regulated by E2 and P at the transcriptional levels in 3T3-L1 cells, and may explain the changes in the HGF production during the mammary gland development, especially decrease in HGF expression during pregnancy when P concentration is high.

The fat and the bad: Mature adipocytes, key actors in tumor progression and resistance

Growing evidence has raised the important roles of adipocytes as an active player in the tumor microenvironment. In many tumors adipocytes are in close contact with cancer cells. They secrete various factors that can mediate local and systemic effects. The adipocyte-cancer cell crosstalk leads to phenotypical and functional changes of both cell types, which can further enhance tumor progression. Moreover, obesity, which is associated with an increase in adipose mass and an alteration of adipose tissue, has been established as a risk factor for cancer incidence and cancer-related mortality. In this review, we summarize the mechanisms of the adipocyte-cancer cell crosstalk in both obese and lean conditions as well as its impact on cancer cell growth, local invasion, metastatic spread and resistance to treatments. Better characterization of cancer-associated adipocytes and the key molecular events in the adipocyte-cancer cell crosstalk will provide insights into tumor biology and suggest efficient therapeutic opportunities.

Mammary Adipose Tissue-Derived Lysophospholipids Promote Estrogen Receptor-Negative Mammary Epithelial Cell Proliferation

Lysophosphatidic acid (LPA), acting in an autocrine or paracrine fashion through G protein-coupled receptors, has been implicated in many physiologic and pathologic processes, including cancer. LPA is converted from lysophosphatidylcholine (LPC) by the secreted phospholipase autotaxin (ATX). Although various cell types can produce ATX, adipocyte-derived ATX is believed to be the major source of circulating ATX and also to be the major regulator of plasma LPA levels. In addition to ATX, adipocytes secrete numerous other factors (adipokines); although several adipokines have been implicated in breast cancer biology, the contribution of mammary adipose tissue-derived LPC/ATX/LPA (LPA axis) signaling to breast cancer is poorly understood. Using murine mammary fat-conditioned medium, we investigated the contribution of LPA signaling to mammary epithelial cancer cell biology and identified LPA signaling as a significant contributor to the oncogenic effects of the mammary adipose tissue secretome. To interrogate the role of mammary fat in the LPA axis during breast cancer progression, we exposed mammary adipose tissue to secreted factors from estrogen receptor-negative mammary epithelial cell lines and monitored changes in the mammary fat pad LPA axis. Our data indicate that bidirectional interactions between mammary cancer cells and mammary adipocytes alter the local LPA axis and increase ATX expression in the mammary fat pad during breast cancer progression. Thus, the LPC/ATX/LPA axis may be a useful target for prevention in patients at risk of ER-negative breast cancer. Cancer Prev Res; 9(5); 367-78. ©2016 AACR.

TGF-β Negatively Regulates CXCL1 Chemokine Expression in Mammary Fibroblasts through Enhancement of Smad2/3 and Suppression of HGF/c-Met Signaling Mechanisms

Fibroblasts are major cellular components of the breast cancer stroma, and influence the growth, survival and invasion of epithelial cells. Compared to normal tissue fibroblasts, carcinoma associated fibroblasts (CAFs) show increased expression of numerous soluble factors including growth factors and cytokines. However, the mechanisms regulating expression of these factors remain poorly understood. Recent studies have shown that breast CAFs overexpress the chemokine CXCL1, a key regulator of tumor invasion and chemo-resistance. Increased expression of CXCL1 in CAFs correlated with poor patient prognosis, and was associated with decreased expression of TGF-β signaling components. The goal of these studies was to understand the role of TGF-β in regulating CXCL1 expression in CAFs, using cell culture and biochemical approaches. We found that TGF-β treatment decreased CXCL1 expression in CAFs, through Smad2/3 dependent mechanisms. Chromatin immunoprecipitation and site-directed mutagenesis assays revealed two new binding sites in the CXCL1 promoter important for Smad2/3 modulation of CXCL1 expression. Smad2/3 proteins also negatively regulated expression of Hepatocyte Growth Factor (HGF), which was found to positively regulate CXCL1 expression in CAFs through c-Met receptor dependent mechanisms. HGF/c-Met signaling in CAFs was required for activity of NF-κB, a transcriptional activator of CXCL1 expression. These studies indicate that TGF-β negatively regulates CXCL1 expression in CAFs through Smad2/3 binding to the promoter, and through suppression of HGF/c-Met autocrine signaling. These studies reveal novel insight into how TGF-β and HGF, key tumor promoting factors modulate CXCL1 chemokine expression in CAFs.

Novel long-acting prostacyclin agonist (ONO-1301) with an angiogenic effect: promoting synthesis of hepatocyte growth factor and increasing cyclic AMP concentration via IP-receptor signaling

The purpose of this study was to evaluate the angiogenic potency of ONO-1301, a novel prostacyclin agonist, using a murine sponge model. Solutions of ONO-1301 or hepatocyte growth factor (HGF), as a positive control, were injected into sponges in the backs of mice, daily for 14 days. Hemoglobin and HGF levels in the sponge were increased for up to 14 days on daily treatment with ONO-1301 while on HGF treatment, they peaked on day 7 and had decreased again by day 14. ONO-1301 also upregulated c-Met expression for 14 days in a dose-dependent manner. When the mice were pretreated with an antibody to HGF or the prostaglandin I (IP)-receptor antagonist CAY10441, the angiogenic effect of ONO-1301 was dramatically reduced. Plasma concentrations of cyclic adenosine monophosphate (cAMP) were increased in a dose-dependent manner by once daily treatment with ONO-1301 for 14 days. This effect was reduced by pretreatment with the IP-receptor antagonist. In conclusion, hemoglobin level was increased by repeated treatment with ONO-1301 for 14 days. It is suggested that ONO-1301 induced angiogenesis by promoting the synthesis of HGF and upregulated c-Met expression, followed by an increase in cAMP concentrations mediated by IP-receptor signaling.

Serum hepatocyte growth factor is associated with truncal fat mass and increased mortality in chronic kidney disease stage 5 patients with protein-energy wasting

BACKGROUND

Obese sarcopenia characterized by increased fat mass and protein-energy wasting (PEW) is not uncommon in chronic kidney disease (CKD) stage 5 patients in whom it is associated with worse outcomes. Serum hepatocyte growth factor (HGF) is associated with obesity in the general population and is increased in CKD patients in whom its association with body composition is not known. We studied the associations between HGF, PEW and body composition, and between HGF and mortality, in CKD stage 5 patients starting dialysis.

METHODS

In 224 CKD stage 5 patients (139 males, mean age 52 years, mean glomerular filtration rate (GFR) 6.6 mL/min), blood samples were obtained for analyses of HGF, high-sensitivity C-reactive protein (hsCRP), glucose, insulin and lipids. Total fat mass index (FMI), truncal fat mass index (TFMI) and lean body mass index (LBMI) assessed by dual-energy X-ray absorptiometry and PEW assessed by subjective global assessment (SGA) were recorded at baseline. Patients were followed up for 5 years.

RESULTS

Serum HGF levels were higher in patients with high TFMI versus low TFMI [3.1 (IQR: 2.4-4.5) versus 2.7 (IQR: 1.9-3.8) ng/mL; P = 0.01] and in those with PEW versus non-PEW [3.4 (IQR: 2.4-3.6) versus 2.8 (IQR: 2.1-3.8) ng/mL; P = 0.03]. Patients with both high TFMI and presence of PEW had significantly (P < 0.001) higher HGF concentration [4.4 (IQR: 3.3-6.6) ng/mL] than other patient groups (high TFMI and non-PEW, low TFMI and PEW or low TFMI and non-PEW). Multivariate linear regression showed that TFMI was an independent predictor of HGF (R(2) = 0.21, P = 0.048). In Cox analysis, patients with high HGF and presence of PEW had worse all-cause mortality after adjusting for age, gender and hsCRP (HR: 3.59, 95% CI: 1.19-5.35).

CONCLUSIONS

Increased TFMI was an independent predictor of HGF in CKD stage 5 patients. Moreover, an elevated HGF level increased the mortality risk in the presence of PEW. These results suggest a central role of HGF in the metabolic and nutritional alterations in CKD stage 5 patients.

Hepatocyte growth factor and interferon-γ inducible protein-10 are related to visceral adiposity

BACKGROUND

Increased production of chemokines by adipose tissue and defective adipose tissue oxygenation as a result of obesity may induce leucocyte infiltration and subsequent systemic inflammation.

OBJECTIVES

1-To determine the relation between the amount of visceral and subcutaneous adipose tissue and the chemokine interferon-γ-inducible protein 10 (IP-10) and angiogenic factor hepatocyte growth factor (HGF). 2-To determine the relation between the metabolic syndrome and IP-10 as well as HGF.

METHODS

Patients originated from the Secondary Manifestations of ARTerial disease (SMART) cohort. In this study, a cohort of 1251 patients with manifest vascular disease was included. Subcutaneous and visceral adipose tissue thickness (SAT and VAT respectively) were measured ultrasonographically. IP-10 and HGF concentrations were measured with Luminex multiplex immuno assay in addition to fasting metabolic parameters. Linear regression analyses with adjustments for age, gender, smoking, estimated glomerular filtration rate, type 2 diabetes mellitus and medication use were applied to quantify the relations between adiposity or metabolic syndrome and IP-10 and HGF concentrations.

RESULTS

VAT was significantly associated with (log)IP-10 and (log)HGF, reflected by significant higher β-values in VAT quartile 4 compared with VAT quartile 1 (reference): β0.155 (95%CI:0.073-0.237) for IP-10 and β0.147 (95%CI:0.076-0.218) for HGF. Per standard deviation increase in VAT, (log)IP-10 levels increased with 0.057 pg/mL (95%CI:0.027-0.087) and (log)HGF increased with 0.051 pg/mL (95%CI:0.025-0.077). Effect estimates were not affected by including body mass index(BMI) in the model. In contrast, SAT was not associated with IP-10 and HGF. Furthermore, the presence of the metabolic syndrome was associated with IP-10 and HGF.

CONCLUSIONS

Visceral adipose tissue but not subcutaneous adipose tissue is significantly associated with circulating levels of IP-10 and HGF, irrespective of BMI.

Human adipose tissue from normal and tumoral breast regulates the behavior of mammary epithelial cells

INTRODUCTION

Stromal-epithelial interactions mediate both breast development and breast cancer progression. In the present work, we evaluated the effects of conditioned media (CMs) of human adipose tissue explants from normal (hATN) and tumor (hATT) breast on proliferation, adhesion, migration and metalloproteases activity on tumor (MCF-7 and IBH-7) and non-tumor (MCF-10A) human breast epithelial cell lines.

MATERIALS AND METHODS

Human adipose tissues were obtained from patients and the conditioned medium from hATN and hATT collected after 24 h of incubation. MCF-10A, MCF-7 and IBH-7 cells were grown and incubated with CMs and proliferation and adhesion, as well as migration ability and metalloprotease activity, of epithelial cells after exposing cell cultures to hATN- or hATT-CMs were quantified. The statistical significance between different experimental conditions was evaluated by one-way ANOVA. Tukey's post hoc tests were performed.

RESULTS

Tumor and non-tumor breast epithelial cells significantly increased their proliferation activity after 24 h of treatment with hATT-CMs compared to control-CMs. Furthermore, cellular adhesion of these two tumor cell lines was significantly lower with hATT-CMs than with hATN-CMs. Therefore, hATT-CMs seem to induce significantly lower expression or less activity of the components involved in cellular adhesion than hATN-CMs. In addition, hATT-CMs induced pro-MMP-9 and MMP-9 activity and increased the migration of MCF-7 and IBH-7 cells compared to hATN-CMs.

CONCLUSIONS

We conclude that the microenvironment of the tumor interacts in a dynamic way with the mutated epithelium. This evidence leads to the possibility to modify the tumor behavior/phenotype through the regulation or modification of its microenvironment. We developed a model in which we obtained CMs from adipose tissue explants completely, either from normal or tumor breast. In this way, we studied the contribution of soluble factors independently of the possible effects of direct cell contact.

Relation of vascular growth factors with CT-derived measures of body fat distribution: the Framingham Heart Study

BACKGROUND

Visceral adiposity is associated with metabolic risk. Given that angiogenesis is a key feature of adipogenesis, variation in the association of levels of circulating vascular growth factors (and their soluble receptors) with distinct body fat compartments may explain differences in the systemic pathogenicity of regional fat depots.

METHODS AND RESULTS

Four body fat compartments [visceral adipose tissue (VAT), sc adipose tissue (SAT), thoracic periaortic fat, and pericardial fat] derived from computed tomography were related to serum concentrations of vascular endothelial growth factor (VEGF), the soluble VEGF receptor (fms-like tyrosine kinase-1), hepatocyte growth factor (HGF), and angiopoietin-2 and its soluble receptor (soluble tyrosine kinase with immunoglobulin-like and EGF-like domains 2 sTie-2) in 1806 Framingham Heart Study participants (mean age 44.9 yr, 44.5% women). In multivariable models, we observed positive associations between several fat compartments and VEGF and HGF levels. The magnitude of the associations were similar for VAT, SAT, and periaortic fat. We observed effect modification by sex. A stronger association was observed between VAT and HGF levels in women; higher VAT and periaortic fat were jointly associated with higher HGF concentrations (P=0.02 and P=0.051, respectively). In women within the highest tertile of VAT, HGF levels significantly increased with higher periaortic fat (P=0.0005).

CONCLUSIONS

In our large community-based sample, greater adiposity was associated with higher circulating growth factor levels in general. Additional studies are warranted to confirm the stronger association of VAT and periaortic fat with HGF in women and to examine its potential contribution to the sex-related differences in cardiometabolic risk.

Mammary adipocytes bioactivate 25-hydroxyvitamin D₃ and signal via vitamin D₃ receptor, modulating mammary epithelial cell growth

The vitamin D(3) receptor (VDR) is present in all microenvironments of the breast, yet it is hypothesized to signal through the epithelium to regulate hormone induced growth and differentiation. However, the influence or contribution of the other microenvironments within the breast that express VDR, like the breast adipose tissue, are yet to be investigated. We hypothesized that the breast adipocytes express the signaling components necessary to participate in vitamin D(3) synthesis and signaling via VDR, modulating ductal epithelial cell growth and differentiation. We utilized human primary breast adipocytes and VDR wild type (WT) and knockout (KO) mice to address whether breast adipocytes participate in vitamin D(3) -induced growth regulation of the ductal epithelium. We report in this study that breast primary adipocytes express VDR, CYP27B1 (1α-hydroxylase, 1α-OHase), the enzyme that generates the biologically active VDR ligand, 1α,25-dihydroxyvitamin D(3) (1,25D(3) ), and CYP24 (24-hydroxylase, 24-OHase), a VDR-1,25D(3) induced target gene. Furthermore, the breast adipocytes participate in bioactivating 25-hydroxyvitamin D(3) (25D(3) ) to the active ligand, 1,25D(3) , and secreting it to the surrounding microenvironment. In support of this concept, we report that purified mammary ductal epithelial fragments (organoids) from VDR KO mice, co-cultured with WT breast adipocytes, were growth inhibited upon treatment with 25D(3) or 1,25D(3) compared to vehicle alone. Collectively, these results demonstrate that breast adipocytes bioactivate 25D(3) to 1,25D(3) , signal via VDR within the adipocytes, and release an inhibitory factor that regulates ductal epithelial cell growth, suggesting that breast adipose tissue contributes to vitamin D(3) -induced growth regulation of ductal epithelium.

Mammographic density and breast cancer risk: the role of the fat surrounding the fibroglandular tissue

Introduction

Both the percent of mammographic density and absolute dense (fibroglandular) area are strong breast cancer risk factors. The role of non-dense (fat) breast tissue is not often investigated, but we hypothesize that this also influences risk. In this study we investigated the independent effects of dense and fat tissue, as well as their combined effect on postmenopausal breast cancer risk.

Methods

We performed a nested case-control study within the EPIC-NL cohort (358 postmenopausal breast cancer cases and 859 postmenopausal controls). We used multivariate logistic regression analyses to estimate breast cancer odds ratios adjusted for body mass index and other breast cancer risk factors.

Results

Large areas of dense (upper (Q5) vs lower quintile (Q1): OR 2.8 95% CI 1.7 to 4.8) and fat tissue (Q5 vs Q1: OR 2.4; 95% CI 1.3 to 4.2) were independently associated with higher breast cancer risk. The combined measure showed that the highest risk was found in women with both a large (above median) area of dense and fat tissue.

Conclusions

Fibroglandular and breast fat tissue have independent effects on breast cancer risk. The results indicate that the non-dense tissue, which represents the local breast fat, increases risk, even independent of body mass index (BMI). When studying dense breast tissue in relation to breast cancer risk, adjustment for non-dense tissue seems to change risk estimates to a larger extent than adjustment for BMI. This indicates that adjustment for non-dense tissue should be considered when studying associations between dense areas and breast cancer risk.

Hormonal mechanisms underlying the relationship between obesity and breast cancer

Given the worldwide epidemic of obesity, it is inevitably an increasingly common comorbidity for women who develop breast cancer; therefore, it is critical to understand its impact on this disease. This review focuses on the influence of obesity on breast cancer development and progression and describes the hormonal factors that may underlie the observations, with particular emphasis on the roles of estrogen, insulin/insulin-like growth factor axis, and adipokines.

Loss of one Tgfbr2 allele in fibroblasts promotes metastasis in MMTV: polyoma middle T transgenic and transplant mouse models of mammary tumor progression

Accumulation of fibroblasts is a phenomenon that significantly correlates with formation of aggressive cancers. While studies have shown that the TGF-β signaling pathway is an important regulator of fibroblast activation, the functional contribution of TGF-β signaling in fibroblasts during multi-step tumor progression remains largely unclear. In previous studies, we used a sub-renal capsule transplantation model to demonstrate that homozygous knockout of the Tgfbr2 gene (Tgbr2(FspKO)) enhanced mammary tumor growth and metastasis. Here, we show for the first time a significant role for loss of one Tgfbr2 allele during multi-step mammary tumor progression. Heterozygous deletion of Tgfbr2 in stromal cells in MMTV-PyVmT transgenic mice (PyVmT/Tgfbr2(hetFspKO) mice) resulted in earlier tumor formation and increased stromal cell accumulation. In contrast to previous studies of Tgbr2(FspKO) fibroblasts, Tgfbr2(hetFspKO) fibroblasts did not significantly increase tumor growth, but enhanced lung metastasis in PyVmT transgenic mice and in co-transplantation studies with PyVmT mammary carcinoma cells. Furthermore, Tgfbr2(hetFspKO) fibroblasts enhanced mammary carcinoma cell invasiveness associated with expression of inflammatory cytokines including CXCL12 and CCL2. Analyses of Tgbr2(FspKO) and Tgfbr2(hetFspKO) fibroblasts revealed differences in the expression of factors associated with metastatic spread, indicating potential differences in the mechanism of action between homozygous and heterozygous deletion of Tgfbr2 in stromal cells. In summary, these studies demonstrate for the first time that loss of one Tgfbr2 allele in fibroblasts enhances mammary metastases in a multi-step model of tumor progression, and demonstrate the importance of clarifying the functional contribution of genetic alterations in stromal cells in breast cancer progression.

Adipocyte derived paracrine mediators of mammary ductal morphogenesis controlled by retinoic acid receptors

We generated a transgenic (Tg)-mouse model expressing a dominant negative-(DN)-RARα, (RARαG303E) under adipocytes-specific promoter to explore the paracrine role of adipocyte retinoic acid receptors (RARs) in mammary morphogenesis. Transgenic adipocytes had reduced level of RARα, β and γ, which coincided with a severely underdeveloped pubertal and mature ductal tree with profoundly decreased epithelial cell proliferation. Transplantation experiments of mammary epithelium and of whole mammary glands implicated a fat-pad dependent paracrine mechanism in the stunted phenotype of the epithelial ductal tree. Co-cultures of primary adipocytes, or in vitro differentiated adipocyte cell line, with mammary epithelium showed that when activated, adipocyte-RARs contribute to generation of secreted proliferative and pro-migratory factors. Gene expression microarrays revealed a large number of genes regulated by adipocyte-RARs. Among them, pleiotrophin (PTN) was identified as the paracrine effectors of epithelial cell migration. Its expression was found to be strongly inhibited by DN-RARα, an inhibition relieved by pharmacological doses of all-trans retinoic acid (atRA) in culture and in vivo. Moreover, adipocyte-PTHR, another atRA responsive gene, was found to be an up-stream regulator of PTN. Overall, these results support the existence of a novel paracrine loop controlled by adipocyte-RAR that regulates the mammary ductal tree morphogenesis.

Adipose derived stem cells (ASCs) isolated from breast cancer tissue express IL-4, IL-10 and TGF-β1 and upregulate expression of regulatory molecules on T cells: do they protect breast cancer cells from the immune response?

Immunomodulatory function of bone marrow derived mesenchymal stem cells in cancer has recently been investigated. But the resident mesenchymal stem cells as whole in cancer and in the breast cancer tissue have not been studied well. In the present work we isolated adipose derived stem cells (ASCs) from breast cancer and normal breast tissues to investigate the expressions of IL-4, IL-10 and transforming growth factor (TGF)-β1 in ASCs and to see if ASCs isolated from patients can modulate the regulatory molecules on peripheral blood lymphocytes. Our results showed that IL-10 and TGF-β1 have significantly higher mRNA expressions in ASCs isolated from breast cancer patients than those from normal individuals (P value <0.05). The culture supernatant of ASCs isolated from breast cancer patients with pathological stage III induced upregulation of the mRNA expression levels of IL-4, TGF-β1, IL-10, CCR4 and CD25 in PBLs. In addition, the percentage of CD4+CD25(high)Foxp3(+) T regulatory cells was increased in vitro. When the same culture supernatant was added to ASCs isolated from normal subjects augmentation of the mRNA expressions of IL-4, IL-10, IL-8, MMP2, VEGF and SDF-1 in normal ASCs was also observed. These data collectively conclude that resident ASCs in breast cancer tissue may have crucial roles in breast tumor growth and progression by inducing regulatory molecules and promoting anti-inflammatory reaction within the tumor microenvironment. Further investigation is required to see if the immune suppression induced by ASCs is an independent property from tumor cells or ASCs gain their immunosuppressive potential from malignant cells.

Diverse and active roles for adipocytes during mammary gland growth and function

The mammary gland is unique in its requirement to develop in close association with a depot of adipose tissue that is commonly referred to as the mammary fat pad. As discussed throughout this issue, the mammary fat pad represents a complex stromal microenvironment that includes a variety of cell types. In this article we focus on adipocytes as local regulators of epithelial cell growth and their function during lactation. Several important considerations arise from such a discussion. There is a clear and close interrelationship between different stromal tissue types within the mammary fat pad and its adipocytes. Furthermore, these relationships are both stage- and species-dependent, although many questions remain unanswered regarding their roles in these different states. Several lines of evidence also suggest that adipocytes within the mammary fat pad may function differently from those in other fat depots. Finally, past and future technologies present a variety of opportunities to model these complexities in order to more precisely delineate the many potential functions of adipocytes within the mammary glands. A thorough understanding of the role for this cell type in the mammary glands could present numerous opportunities to modify both breast cancer risk and lactation performance.

Adipose stroma induces branching morphogenesis of engineered epithelial tubules

The mammary gland and other treelike organs develop their characteristic fractal geometries through branching morphogenesis, a process in which the epithelium bifurcates and invades into the surrounding stroma. Controlling the pattern of branching is critical for engineering these organs. In vivo, the branching process is instructed by stromal-epithelial interactions and adipocytes form the largest component of the fatty stroma that surrounds the mammary epithelium. Here, we used microlithographic approaches to engineer a three-dimensional culture model that enables analysis of the effect of adipocytes on the pattern of branching morphogenesis of mammary epithelial cells. We found that adipocyte-rich stroma induces branching through paracrine signals, including hepatocyte growth factor, but does not affect the branching pattern per se. This tissue engineering approach can be expanded to other organs, and should enable piecemeal analysis of the cellular populations that control patterning during normal development.

Effects of adipocytes on the proliferation and differentiation of prostate cancer cells in a 3-D culture model

OBJECTIVE

To investigate how the mechanism of adipocyte-prostate cancer cell interaction affects the proliferation and differentiation of prostate cancer cells.

METHODS

An androgen-dependent cell line (LNCaP), two androgen-independent cell lines (PC-3, DU145), and mature adipocytes harvested from male Wistar rats were used. Cancer cells were co-cultured with the isolated mature adipocytes in 3-D collagen gel matrix culture. The morphology and proliferative ability of the prostate cancer cells were examined. With regard to the activation of the phosphatidylinositol 3-kinase (PI3K) pathway, the expression of phosphatase and tensin homologue deleted on chromosome ten (PTEN), Akt and Bad were determined by immunohistochemistry.

RESULTS

LNCaP cells co-cultured with adipocytes formed larger clusters than those of the control. PC-3 cells co-cultured with adipocytes did not form larger clusters, but formed spherical and spindle-shaped cells. The phosphorylation of Akt in PC-3 cells was greater in the co-cultured group compared with the controls, but there were no significant differences in the phosphorylation of Akt with regard to LNCaP and DU145 cells.

CONCLUSIONS

Adipocytes could modulate the proliferation and differentiation of prostate cancer cell lines. Activation of the PI3K pathway might be involved in the prostate cancer cell-adipocyte interaction.

Expression profile of IL-8 and growth factors in breast cancer cells and adipose-derived stem cells (ASCs) isolated from breast carcinoma

Adipose-derived stem cells (ASCs) are regarded as a major player of breast cancer microenvironment. By production of various growth factors and expression of regulatory molecules, it is postulated that ASCs protect breast cancer cells from the host immune responses. In this study, the expressions of insulin-like growth factor-1 (IGF-1), hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), CXCL8 (IL-8) in breast cancer cells and adipose-derived stem cells isolated from breast tissue of women with breast cancer were investigated. The results were analyzed comparatively in normal ASCs isolated from healthy normal women. In case of breast cancer tissues, results were analyzed between high stage and low stage patients. The expressions of extracted mRNAs were determined using real-time quantitative RT-PCR. As a result, in breast cancer tissues, IGF-1 and IL-8 mRNAs had 28.6 and 56-fold more expressions in high stage compared to low stage patients. In ASCs, relative quantifications (RQ) of VEGF, IL-8, HGF and IGF-1 was about 2-fold higher in patients than controls. Data of this study conclude that presence of resident ASCs within the scaffold of breast tissue may support breast tumor growth and progression through the expressions of tumor promoting factors.

Hepatocyte growth factor and the risk of ischemic stroke developing among postmenopausal women: results from the Women's Health Initiative

BACKGROUND AND PURPOSE

Hepatocyte growth factor (HGF) is a potent angiogenic factor and may play a role in the development and progression of atherosclerotic lesions, the underlying mechanism of cardiovascular disease. However, there have been no prospective studies examining the relationship between HGF levels and risk of stroke.

METHODS

We conducted a nested case-control study (972 incident stroke cases and 1:1 age-matched and race-matched controls) to prospectively evaluate the association between plasma HGF and risk of ischemic stroke within the Women's Health Initiative Observational Study, a cohort of postmenopausal women aged 50 to 79 years.

RESULTS

Baseline HGF levels were correlated positively with body mass index, systolic blood pressure, low-density lipoprotein cholesterol, insulin resistance, and inflammatory markers, such as C-reactive protein, and inversely with high-density lipoprotein cholesterol (all P<0.05). Baseline HGF levels were higher among cases than controls (geometric means, 601.8 vs 523.2 pg/mL; P=0.003). Furthermore, the risk of incident ischemic stroke was significantly greater among women in the highest vs lowest quartile of plasma HGF levels (OR, 1.46; 95% CI, 1.12-1.91; P(trend)=0.003) in a conditional logistic regression model that adjusted for body mass index. These results were only slightly attenuated after further adjustment for additional stroke risk factors (OR, 1.39; 95% CI, 1.04-1.85; P(trend)=0.023).

CONCLUSIONS

Circulating levels of HGF are associated with an increased risk of incident ischemic stroke, independent of obesity and other risk factors for cardiovascular disease, among postmenopausal women aged 50 to 79 years.

Does breast size modify the association between mammographic density and breast cancer risk?

BACKGROUND

Both the absolute and the percent of mammographic density are strong and independent risk factors for breast cancer. Previously, we showed that the association between mammographic density and breast cancer risk tended to be weaker in African American than in White U.S. women. Because African American women have a larger breast size, we assessed whether the association between mammographic density and breast cancer was less apparent in large than in small breasts.

METHODS

We assessed mammographic density on mammograms from 348 African American and 507 White women, 479 breast cancer patients and 376 control subjects, from a case-control study conducted in Los Angeles County. We estimated odds ratios (OR) for breast cancer with increasing mammographic density, and the analyses were stratified by mammographic breast area.

RESULTS

Median breast size was 168.4 cm2 in African American women and 121.7 cm2 in White women (P for difference <0.001). For absolute density, adjusted ORs (95% confidence intervals) per increase of 10 cm2 were 1.32 (1.13-1.54), 1.14 (1.03-1.26), and 1.02 (0.98-1.07) in the first, second, and third tertiles of breast area, respectively (P for effect modification by breast area = 0.005). The results for percent density were similar although weaker; adjusted ORs per 10% increase (absolute value) in percent density were 1.22 (1.05-1.40), 1.22 (1.06-1.41), and 1.03 (0.90-1.18 P for effect modification by breast area = 0.34).

CONCLUSION

Our results indicate that the association between mammographic density and breast cancer may be weaker in women with larger breasts.

Cytokine profile of human adipose-derived stem cells: expression of angiogenic, hematopoietic, and pro-inflammatory factors

Adipose tissue serves as a source of adipokines and cytokines with both local and systemic actions in health and disease. In this study, we examine the hypothesis that multipotent human adipose-derived stem cells (ASCs), capable of differentiating along the adipocyte, chondrocyte, and osteoblast pathways, contribute to adipose tissue-derived cytokine secretion. Following exposure to basic fibroblast growth factor (bFGF) or epidermal growth factor (EGF), the ASCs significantly increase their secretion of hepatocyte growth factor (HGF), a cytokine implicated in hematopoiesis, vasculogenesis, and mammary epithelial duct formation. Ascorbic acid synergizes with these inductive factors, further increasing HGF levels. Following exposure to lipopolysaccharide, ASCs increase their secretion of both hematopoietic (granulocyte/monocyte, granulocyte, and macrophage colony stimulating factors, interleukin 7) and proinflammatory (interleukins 6, 8, and 11, tumor necrosis factor alpha) cytokines based on ELISA and RT-PCR. In co-cultures established with umbilical cord blood-derived CD34(+) cells, the ASCs support long-term hematopoiesis in vitro. Furthermore, in short-term 12-day co-cultures, the ASC maintain and expand the numbers of both myeloid and lymphoid progenitors. These observations are consistent with the functionality of the secreted cytokines and confirm recent reports by other laboratories concerning the hematopoietic supportive capability of ASCs. We conclude that the ASCs display cytokine secretory properties similar to those reported for bone marrow-derived mesenchymal stem cells (MSCs).

Hepatocyte growth factor induces glucose uptake in 3T3-L1 adipocytes through A Gab1/phosphatidylinositol 3-kinase/Glut4 pathway

Adipose tissue is a source of hepatocyte growth factor (HGF), and circulating HGF levels have been associated with elevated body mass index in human. However, the effects of HGF on adipocyte functions have not yet been investigated. We show here that in 3T3-L1 adipocytes HGF stimulates the phosphatidylinositol (PI) 3-kinase-dependent protein kinase B (PKB) activity, AS160 phosphorylation, Glut4 translocation, and consequently, glucose uptake. The initial steps involved in HGF- and insulin-induced glucose uptake are different. HGF enhanced the tyrosine phosphorylation of Gab1, leading to the recruitment of the p85-regulated subunit of PI 3-kinase, whereas p85 was exclusively recruited by IRS1 in response to insulin. In adipocytes rendered insulin-resistant by a long-lasting tumor necrosis factor alpha treatment, the protein level of Gab1 was strongly decreased, and HGF-stimulated PKB activation and glucose uptake were also altered. Moreover, treatment of 3T3-L1 adipocytes with thiazolidinedione, an anti-diabetic drug, enhanced the expression of both HGF and its receptor. These data provide the first evidence that in vitro HGF promotes glucose uptake through a Gab1/PI 3-kinase/PKB/AS160 pathway which was altered in tumor necrosis factor alpha-treated adipocytes.

Plasma levels of leptin and mammographic density among postmenopausal women: a cross-sectional study

Introduction

Obesity has been linked to increased risk of breast cancer in postmenopausal women. Increased peripheral production of estrogens has been regarded as the main cause for this association, but other features of increased body fat mass may also play a part. Leptin is a protein produced mainly by adipose tissue and may represent a growth factor in cancer. We examined the association between leptin plasma levels and mammographic density, a biomarker for breast cancer risk.

Methods

We included data from postmenopausal women aged 55 and older, who participated in a cross-sectional mammography study in Tromsø, Norway. Mammograms, plasma leptin measurements as well as information on anthropometric and hormonal/reproductive factors were available from 967 women. We assessed mammographic density using a previously validated computer-assisted method. Multiple linear regression analysis was applied to investigate the association between mammographic density and quartiles of plasma leptin concentration. Because we hypothesized that the effect of leptin on mammographic density could vary depending on the amount of nondense or fat tissue in the breast, we also performed analyses on plasma leptin levels and mammographic density within tertiles of mammographic nondense area.

Results

After adjusting for age, postmenopausal hormone use, number of full-term pregnancies and age of first birth, there was an inverse association between leptin and absolute mammographic density (P_trend = 0.001). When we additionally adjusted for body mass index and mammographic nondense area, no statistically significant association between plasma leptin and mammographic density was found (P_trend = 0.16). Stratified analyses suggested that the association between plasma leptin and mammographic density could differ with the amount of nondense area of the mammogram, with the strongest association between leptin and mammographic absolute density in the stratum with the medium breast fat content (P_trend = 0.003, P for interaction = 0.05).

Conclusion

We found no overall consistent association between the plasma concentration of leptin and absolute mammographic density. Although weak, there was some suggestion that the association between leptin and mammographic density could differ with the amount of fat tissue in the breast.

Hepatocyte Growth Factor Regulates E Box–Dependent Plasminogen Activator Inhibitor Type 1 Gene Expression in HepG2 Liver Cells

OBJECTIVE

We sought to determine the etiologic mechanism of pleiotropic growth factor, hepatocyte growth factor (HGF), as a regulator of hepatic synthesis of plasminogen activator inhibitor (PAI)-1, the physiological inhibitor of fibrinolysis and a potential inducer of atherothrombosis.

METHODS AND RESULTS

HGF increased PAI-1 mRNA expression and PAI-1 protein accumulation in the conditioned media of human liver-derived HepG2 cells, and increased hepatic PAI-1 mRNA expression in vivo in mice. HGF-inducible PAI-1 mRNA was attenuated by U0126, a specific inhibitor of mitogen-activated protein kinase (MAPK) kinase, and genistein, an inhibitor of tyrosine kinase. HGF increased the human PAI-1 promoter (-829 to +36 bp) activity, and deletion and mutation analysis uncovered a functional E box (5'-CACATG-3') at positions -158 to -153 bp. Electrophoretic mobility shift assays demonstrated that this E box binds upstream stimulatory factors (USFs). HGF phosphorylated USFs through MAPK and tyrosine kinase pathways. Co-transfection of USF1 expression vector increased PAI-1 promoter activity. Sterol regulatory element-binding protein-1 attenuated HGF-inducible PAI-1 promoter activity.

CONCLUSIONS

Because USFs are involved in the regulation of carbohydrates and lipid metabolism, HGF-mediated PAI-1 production may provide a novel link between atherothrombosis and metabolic derangements. Targeting HGF signaling pathway may modulate the thrombotic risk in high-risk patients.

Adipose tissue production of hepatocyte growth factor contributes to elevated serum HGF in obesity

Serum HGF is elevated in obese individuals. This study examined the contribution of excess adipose tissue to increased circulating HGF levels in obesity. Serum HGF was measured by ELISA before and after weight loss due to bariatric surgery or a 24-h fast. At 6.1 +/- 0.1 mo following surgery, BMI (50.6 +/- 1.6 vs. 35.1 +/- 1.3 kg/m(2); P < 0.0001) and serum HGF were significantly decreased (1,164 +/- 116 vs. 529 +/- 39 pg/ml, P < 0.001). A 24-h fast did not change serum HGF, but serum leptin was significantly reduced (67.7 +/- 7.1 vs. 50.3 +/- 8.3 ng/ml, P = 0.02). HGF secretion in vitro from adipocytes of obese (BMI 40.3 +/- 2.8 kg/m(2)) subjects was significantly greater (80.9 +/- 10.4 vs. 21.5 +/- 4.0 pg/10(5) cells, P = 0.008) than release from adipocytes of lean (BMI 23.3 +/- 1.4 kg/m(2)) subjects. HGF mRNA levels determined by real-time RT-PCR were not different in adipocytes from lean (BMI 24.0 +/- 0.8 kg/m(2)) and obese (45.7 +/- 3.0 kg/m(2)) subjects, but serum HGF was significantly elevated in the obese individuals studied (787 +/- 61 vs. 489 +/- 49 pg/ml, P = 0.001). TNF-alpha (24 h treatment) significantly increased HGF release from subcutaneous adipocytes 23.6 +/- 8.3% over control (P = 0.02). These data suggest that elevated serum HGF in obesity is in part attributable to excess adipose tissue and that this effect can be reversed by reducing adipose tissue mass through weight loss. Increased HGF secretion from adipocytes of obese subjects may be due to posttranscriptional events possibly related to adipocyte size and stimulation by elevated TNF-alpha in the adipose tissue of obese individuals.

Angiogenic factors are elevated in overweight and obese individuals

BACKGROUND

Adipose tissue produces both vascular growth factors and inhibitors. Since obesity is associated with expansion of the capillary bed in regional adipose depots the balance between these factors may favor angiogenesis.

OBJECTIVE

To investigate the relationship between body mass index and serum concentrations of vascular growth factors in human subjects.

METHODS

Vascular endothelial growth factor (VEGF), VEGF-C, VEGF-D, soluble VEGF receptor-2 (sVEGFr2), hepatocyte growth factor (HGF), angiopoietin-2, angiogenin and endostatin concentrations were measured in serum collected from 58 lean (24 males, 34 female, mean BMI, 22.2+/-0.3) and 42 overweight and obese (16 males and 26 females, mean BMI, 33.5+/-1.2) subjects after an overnight fast.

RESULTS

Sexual dimorphism was apparent in the serum concentrations of VEGF-C, VEFG-D and angiopoietin-2 with significantly higher levels in female compared to male subject. VEGF, VEGF-C, VEGF-D, soluble VEGF receptor-2, angiopoietin-2, angiogenin and endostatin but not HGF were significantly elevated in overweight and obese subjects. Positive correlations between BMI and the serum concentrations of VEGF-C, VEGF-D, sVEGF-R2, angiopoietin-2, angiogenin and endostatin were observed even after adjustment for gender and age.

CONCLUSIONS

Increased levels of vascular growth factors as well as the angiogenesis inhibitor endostatin are present in overweight and obese subjects and may contribute to previously documented increased risk of metastatic disease in obese subjects with cancer.

Promotion of prostatic metastatic migration towards human bone marrow stoma by Omega 6 and its inhibition by Omega 3 PUFAs

Epidemiological studies have shown not only a relationship between the intake of dietary lipids and an increased risk of developing metastatic prostate cancer, but also the type of lipid intake that influences the risk of metastatic prostate cancer. The Omega-6 poly-unsaturated fatty acid, Arachidonic acid, has been shown to enhance the proliferation of malignant prostate epithelial cells and increase the risk of advanced prostate cancer. However, its role in potentiating the migration of cancer cells is unknown. Here we show that arachidonic acid at concentrations Collapse

Key Words

• prostate cancer
• arachidonic acid
• metastasis
• bone marrow
• omega 6
• omega 3

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MESH Headings

• Arachidonic Acid/pharmacology
• Bone Marrow Neoplasms/secondary
• Cell Movement
• Dose-Response Relationship, Drug
• Fatty Acids, Omega-3/pharmacology
• Fatty Acids, Omega-6/pharmacology
• Humans
• Male
• Neoplasm Invasiveness/physiopathology
• Prostatic Neoplasms/pathology
• Risk Factors
• Tumor Cells, Cultured

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Grants Collapse

Affiliation(s)

M D Brown ProMPT Genito Urinary Cancer Research Group, Cancer Research UK.
C A Hart
E Gazi
S Bagley
N W Clarke

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Adipocytokines: leptin--the classical, resistin--the controversical, adiponectin--the promising, and more to come

With the growing prevalence of obesity, scientific interest in the biology of adipose tissue has been extended to the secretory products of adipocytes, since they are increasingly shown to affect several aspects in the pathogenesis of obesity-related diseases. The cloning of the ob gene is consistent with this concept and suggests that body fat content in adult rodents is regulated by a negative feedback loop centred in the hypothalamus. In recent years, a number of additional signalling molecules secreted by adipose tissue have been discovered, commonly referred to as 'adipocytokines'. Among these, adiponectin is perhaps the most interesting and promising compound for the clinician since it has profound protective actions in the pathogenesis of diabetes and cardiovascular disease. Adiponectin is low in obese subjects and, in particular, insulin-resistant patients. In contrast, resistin seems to be of greater relevance in relation to the immune stress response than in the regulation of glucose homeostasis. However, inflammatory processes have recently been connected with the development of atherosclerosis. Finally, little is known regarding the clinical relevance of visfatin. Recent research has revealed many functions of adipocytokines extending far beyond metabolism, such as immunity, cancer and bone formation. This report aims to review some of the recent topics of adipocytokine research that may be of particular importance.