Evidence that leptin through STAT and CREB signaling enhances cyclin D1 expression and promotes human endometrial cancer proliferation

Potential JAK2 Inhibitors from Selected Natural Compounds: A Promising Approach for Complementary Therapy in Cancer Patients

Background

Janus-activated kinase 2 (JAK2) plays a pivotal role in numerous essential biological processes, including proliferation, apoptosis, and metastasis in human cells. Prior studies have indicated that inhibiting JAK2 could be a promising strategy to mitigate cell proliferation and induce apoptosis in tumor cells.

Objectives

This study aimed to estimate the binding affinity of 79 herbal compounds, comprising 46 flavonoids, 21 anthraquinones, and 12 cinnamic acids, to the ATP-binding cleft of JAK2 to identify potential herbal inhibitors of JAK2.

Methods

The binding affinities between ligands and JAK2 were calculated utilizing AutoDock 4.0 software in conjunction with the Cygwin environment. Cross-validation was conducted using the Schrödinger tool. Molecular dynamics simulations were employed to evaluate the stability of docked poses for the most significant JAK2 inhibitors. Furthermore, the Discovery Studio Visualizer tool was utilized to elucidate interactions between the top-ranked JAK2 inhibitors and residues within the JAK2 ATP-binding site.

Results

Twelve flavonoids, two anthraquinones, and three cinnamic acids demonstrated substantial binding affinities to the protein kinase domain of the receptor, with a criterion of ΔGbinding < -10 kcal/mol. Among the studied flavonoids, anthraquinones, and cinnamic acid derivatives, orientin, chlorogenic acid, and pulmatin emerged as the most potent JAK2 inhibitors, exhibiting ΔGbinding scores of -14.49, -11.87, and -10.76 kcal/mol, respectively. Furthermore, the docked poses of orientin, pulmatin, and chlorogenic acid remained stable throughout 60 ns computer simulations. The average root mean square deviation values calculated for JAK2 when complexed with orientin, chlorogenic acid, and pulmatin were 2.04 Å, 2.06 Å, and 1.95 Å, respectively.

Conclusion

This study underscores the robust inhibitory potential of orientin, pulmatin, and chlorogenic acid against JAK2. The findings hold promise for the development of novel and effective drugs for cancer treatment.

TSLP enhances progestin response in endometrial cancer via androgen receptor signal pathway

BACKGROUND

The enriched proteins within in vitro fertilisation (IVF)-generated human embryonic microenvironment could reverse progestin resistance in endometrial cancer (EC).

METHODS

The expression of thymic stromal lymphopoietin (TSLP) in EC was evaluated by immunoblot and IHC analysis. Transcriptome sequencing screened out the downstream pathway regulated by TSLP. The role of TSLP, androgen receptor (AR) and KANK1 in regulating the sensitivity of EC to progestin was verified through a series of in vitro and in vivo experiments.

RESULTS

TSLP facilitates the formation of a BMP4/BMP7 heterodimer, resulting in activation of Smad5, augmenting AR signalling. AR in turn sensitises EC cells to progestin via KANK1. Downregulation of TSLP, loss of AR and KANK1 in EC patients are associated with tumour malignant progress. Moreover, exogenous TSLP could rescue the anti-tumour effect of progestin on mouse in vivo xenograft tumour.

CONCLUSIONS

Our findings suggest that TSLP enhances the sensitivity of EC to progestin through the BMP4/Smad5/AR/KANK1 axis, and provide a link between embryo development and cancer progress, paving the way for the establishment of novel strategy overcoming progestin resistance using embryo original factors.

Inhibition of CREB Binding and Function with a Dual-Targeting Ligand

CBP/p300 is a master transcriptional coactivator that regulates gene activation by interacting with multiple transcriptional activators. Dysregulation of protein-protein interactions (PPIs) between the CBP/p300 KIX domain and its activators is implicated in a number of cancers, including breast, leukemia, and colorectal cancer. However, KIX is typically considered "undruggable" because of its shallow binding surfaces lacking both significant topology and promiscuous binding profiles. We previously reported a dual-targeting peptide (MybLL-tide) that inhibits the KIX-Myb interaction with excellent specificity and potency. Here, we demonstrate a branched, second-generation analogue, CREBLL-tide, that inhibits the KIX-CREB PPI with higher potency and selectivity. Additionally, the best of these CREBLL-tide analogues shows excellent and selective antiproliferation activity in breast cancer cells. These results indicate that CREBLL-tide is an effective tool for assessing the role of KIX-activator interactions in breast cancer and expanding the dual-targeting strategy for inhibiting KIX and other coactivators that contain multiple binding surfaces.

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.

Leptin: A Heavyweight Player in Obesity-Related Cancers

Obesity, defined as the abnormal or excessive expansion of white adipose tissue, has reached pandemic proportions and is recognized as an important health concern since it is a common root for several comorbidities, including malignancies. Indeed, the current knowledge of the white adipose tissue, which shifts its role from an energy storage tissue to an important endocrine and metabolic organ, has opened up new avenues for the discovery of obesity's effects on tumor biology. In this review, we will report the epidemiological studies concerning the strong impact of obesity in several types of cancer and describe the mechanisms underlying the heterotypic signals between cancer cell lines and adipocytes, with particular emphasis on inflammation, the insulin/IGF-1 axis, and adipokines. Among the adipokines, we will further describe the in vitro, in vivo, and clinical data concerning the role of leptin, recognized as one of the most important mediators of obesity-associated cancers. In fact, leptin physiologically regulates energy metabolism, appetite, and reproduction, and several studies have also described the role of leptin in affecting cancer development and progression. Finally, we will summarize the newest pharmacological strategies aimed at mitigating the protumorigenic effects of leptin, underlining their mechanisms of action.

LIM1 contributes to the malignant potential of endometrial cancer

Introduction

The incidence of endometrial cancer (EC) has been increasing worldwide. However, because there are limited chemotherapeutic options for the treatment of EC, the prognosis of advanced-stage EC is poor.

Methods

Gene expression profile datasets for EC cases registered in The Cancer Genome Atlas (TCGA) was reanalyzed. Highly expressed genes in advanced-stage EC (110 cases) compared with early-stage EC (255 cases) were extracted and Gene Ontology (GO) enrichment analysis was performed. Among the enriched genes, Kaplan-Meier (KM) plotter analysis was performed. Candidate genes expression was analyzed in HEC50B cells and Ishikawa cells by RT-qPCR. In HEC50B cells, LIM homeobox1 (LIM1) was knocked down (KD) and cell proliferation, migration, and invasion ability of the cells were evaluated. Xenografts were generated using LIM1-KD cells and tumor growth was evaluated. Ingenuity Pathway Analysis (IPA) of RNA-seq data using LIM-KD cells was performed. Expression of phospho-CREB and CREB-related proteins were evaluated in LIM1-KD cells by western blotting and in xenograft tissue by immunofluorescent staining. Two different CREB inhibitors were treated in HEC50B and cell proliferation was evaluated by MTT assay.

Results

Reanalysis of TCGA followed by GO enrichment analysis revealed that homeobox genes were highly expressed in advanced-stage EC. Among the identified genes, KM plotter analysis showed that high LIM1 expression was associated with a significantly poorer prognosis in EC. Additionally, LIM1 expression was significantly higher in high-grade EC cell lines, HEC50B cells than Ishikawa cells. Knockdown of LIM1 showed reduced cell proliferation, migration and invasion in HEC50B cells. Xenograft experiments revealed that tumor growth was significantly suppressed in LIM1-KD cells. IPA of RNA-seq data using LIM-KD cells predicted that the mRNA expression of CREB signaling-related genes was suppressed. Indeed, phosphorylation of CREB was decreased in LIM1-KD cells and LIM1-KD cells derived tumors. HEC50B cells treated by CREB inhibitors showed suppression of cell proliferation.

Conclusion and discussion

Collectively, these results suggested that high LIM1 expression contributed to tumor growth via CREB signaling in EC. Inhibition of LIM1 or its downstream molecules would be new therapeutic strategies for EC.

Body Mass Index and Cancer Risk: An Umbrella Review of Meta-Analyses of Observational Studies

Increasing evidence indicates that obesity is a risk factor for various tumors. We aimed to clarify the evidence for an association between body mass index (BMI) and cancer risk based on existing systematic reviews and meta-analyses. Eighteen studies were included in this umbrella review after searching PubMed, Embase and Web of science. The results revealed that underweight was inversely associated with the incidence of brain tumors and positively related to the risk of esophageal and lung cancer. Overweight enhances the incidence of brain tumors, kidney cancer, endometrial cancer, ovarian cancer, multiple myeloma, bladder cancer and liver cancer. Obesity was related to the increased incidence of brain tumors, cervical cancer, kidney cancer, endometrial cancer, esophageal cancer, gastric cancer, ovarian cancer, multiple myeloma, gallbladder cancer, bladder cancer, colorectal cancer, liver cancer, thyroid cancer and Hodgkin's lymphoma. Moreover, dose-response analysis was conducted by 10 studies, and the results demonstrated that each 5 Kg/m² increase in BMI was associated with a 1.01- to 1.13-fold increased risk of general brain tumors, multiple myeloma, bladder cancer, pancreatic cancer, breast cancer, and non-Hodgkin's lymphoma. Every 1 Kg/m² increase in BMI was linked to 6% and 4% increases in the risk of kidney cancer and gallbladder cancer, respectively.

Cancer-Associated Adipocytes and Breast Cancer: Intertwining in the Tumor Microenvironment and Challenges for Cancer Therapy

Adipocytes are the main components in breast tissue, and cancer-associated adipocytes (CAAs) are one of the most important components in the tumor microenvironment of breast cancer (BC). Bidirectional regulation was found between CAAs and BC cells. BC facilitates the dedifferentiation of adjacent adipocytes to form CAAs with morphological and biological changes. CAAs increase the secretion of multiple cytokines and adipokines to promote the tumorigenesis, progression, and metastasis of BC by remodeling the extracellular matrix, changing aromatase expression, and metabolic reprogramming, and shaping the tumor immune microenvironment. CAAs are also associated with the therapeutic response of BC and provide potential targets in BC therapy. The present review provides a comprehensive description of the crosstalk between CAAs and BC and discusses the potential strategies to target CAAs to overcome BC treatment resistance.

Role of adipocytokines in endometrial cancer progression

Endometrial cancer is considered a significant barrier to increasing life expectancy and remains one of the most common malignant cancers among women in many countries worldwide. The increasing mortality rates are potentially proportional to the increasing obesity incidence. Adipose tissue secretes numerous adipocytokines, which may play important roles in endometrial cancer progression. In this scenario, we describe the role of adipocytokines in cell proliferation, cell invasion, cell adhesion, inflammation, angiogenesis, and anti-apoptotic action. A better understanding of the mechanisms of these adipocytokines may open up new therapeutic avenues for women with endometrial cancer. In the future, larger prospective studies focusing on adipocytokines and specific inhibitors should be directed at preventing the rapidly increasing prevalence of gynecological malignancies.

Adipocytokines and disease progression in endometrial cancer: a systematic review

The objective of the study was to document the effect of adipocytokines on endometrial cancer progression. A search of the databases CINAHL, Medline, PubMed, Cochrane, Web of Science, Embase and Google Scholar was performed for English language articles from January 2000 to December 2020 using the keywords: (Endometrial cancer) AND (progression OR metastasis) AND (adipocytokine OR adiponectin OR leptin OR visfatin OR IL-6 OR TNF-α OR adipokine OR cytokine). Forty-nine studies on adipocytokines have been included in this review. Adiponectin has been linked with anti-proliferative and anti-metastatic effects on endometrial cancer cells and is associated with a better prognosis. Leptin, visfatin and resistin are linked to the stimulation of endometrial cancer growth, proliferation, invasion and metastasis and are associated with worse prognosis or with a higher grade/stage of endometrial cancer. IL-6, Il-11, IL-31, IL-33, TNF-α, TGF-β1, SDF-1 and CXCR are involved in endometrial cancer cell growth and metastasis or involved in epithelial mesenchymal transformation (EMT) or associated with advanced disease. Adipocytokines have been found to directly impact endometrial cancer cell proliferation, invasion and migration. These molecules and their signalling pathways may be used to determine prognosis and course of the disease and may also be exploited as potential targets for cancer treatment and prevention of progression.

New Insights Into the Pivotal Role of CREB-Regulated Transcription Coactivator 1 in Depression and Comorbid Obesity

Depression and obesity are major public health concerns, and there is mounting evidence that they share etiopathophysiological mechanisms. The neurobiological pathways involved in both mood and energy balance regulation are complex, multifactorial and still incompletely understood. As a coactivator of the pleiotropic transcription factor cAMP response element-binding protein (CREB), CREB-regulated transcription coactivator 1 (CRTC1) has recently emerged as a novel regulator of neuronal plasticity and brain functions, while CRTC1 dysfunction has been associated with neurodegenerative and psychiatric diseases. This review focuses on recent evidence emphasizing the critical role of CRTC1 in the neurobiology of depression and comorbid obesity. We discuss the role of CRTC1 downregulation in mediating chronic stress-induced depressive-like behaviors, and antidepressant response in the light of the previously characterized Crtc1 knockout mouse model of depression. The putative role of CRTC1 in the alteration of brain energy homeostasis observed in depression is also discussed. Finally, we highlight rodent and human studies supporting the critical involvement of CRTC1 in depression-associated obesity.

Long-term outcomes of progestin plus metformin as a fertility-sparing treatment for atypical endometrial hyperplasia and endometrial cancer patients

Objective

The present study investigated long-term outcomes of medroxyprogesterone acetate (MPA) plus metformin therapy in terms of control of atypical endometrial hyperplasia (AEH) and endometrial cancer (EC), and post-treatment conception.

Methods

We retrospectively analyzed 63 patients (42 with EC; 21 with AEH) who underwent fertility-sparing management using MPA plus metformin. MPA (400 mg/day) and metformin (750–2,250 mg/day) were administered to achieve complete response (CR). Metformin was administered until conception, even after MPA discontinuation.

Results

Of the total patients, 48 (76%) had a body mass index (BMI) ≥25 kg/m² and 43 (68%) showed insulin resistance. Sixty-one patients (97%) achieved CR within 18 months. CR rates at 6, 8–9, and 12 months were 60%, 84%, and 90%, respectively. During a median follow-up period of 57 months (range, 13–115 months), relapse occurred in 8 of 61 patients (13.1%) who had achieved CR. Relapse-free survival (RFS) in all patients at 5 years was 84.8%. Upon univariate analysis, patients with BMI ≥25 kg/m² had significantly better prognoses than did those with BMI <25 kg/m² (odds ratio=0.19; 95% confidence interval=0.05–0.66; p=0.009). Overall pregnancy and live birth rates per patient were 61% (19/31) and 45% (14/31), respectively.

Conclusions

MPA plus metformin is efficacious in terms of RFS and post treatment conception. Moreover, metformin may be more efficacious for patients with BMI ≥25 kg/m².

FoxO3a as a Positive Prognostic Marker and a Therapeutic Target in Tamoxifen-Resistant Breast Cancer

Background: Resistance to endocrine treatments is a major clinical challenge in the management of estrogen receptor positive breast cancers. Although multiple mechanisms leading to endocrine resistance have been proposed, the poor outcome of this subgroup of patients demands additional studies. Methods: FoxO3a involvement in the acquisition and reversion of tamoxifen resistance was assessed in vitro in three parental ER+ breast cancer cells, MCF-7, T47D and ZR-75-1, in the deriving Tamoxifen resistant models (TamR) and in Tet-inducible TamR/FoxO3a stable cell lines, by growth curves, PLA, siRNA, RT-PCR, Western blot, Immunofluorescence, Transmission Electron Microscopy, TUNEL, cell cycle, proteomics analyses and animal models. FoxO3a clinical relevance was validated in silico by Kaplan–Meier survival curves. Results: Here, we show that tamoxifen resistant breast cancer cells (TamR) express low FoxO3a levels. The hyperactive growth factors signaling, characterizing these cells, leads to FoxO3a hyper-phosphorylation and subsequent proteasomal degradation. FoxO3a re-expression by using TamR tetracycline inducible cells or by treating TamR with the anticonvulsant lamotrigine (LTG), restored the sensitivity to the antiestrogen and strongly reduced tumor mass in TamR-derived mouse xenografts. Proteomics data unveiled novel potential mediators of FoxO3a anti-proliferative and pro-apoptotic activity, while the Kaplan–Meier analysis showed that FoxO3a is predictive of a positive response to tamoxifen therapy in Luminal A breast cancer patients. Conclusions: Altogether, our data indicate that FoxO3a is a key target to be exploited in endocrine-resistant tumors. In this context, LTG, being able to induce FoxO3a, might represent a valid candidate in combination therapy to prevent resistance to tamoxifen in patients at risk.

Preventive Effects by Black Raspberries of Endometrial Carcinoma Initiation and Promotion Induced by a High-Fat Diet

SCOPE

The chemopreventive effects of black raspberries (BRBs) have not been studied in endometrial tumorigenesis. Here, they are examined in a mouse model of endometrial cancer.

METHODS AND RESULTS

Wild-type and Pten heterozygous (+/-) female mice are weaned at 3 weeks and fed with four AIN-93G diets: 93G; 93G+5% BRBs powder; high-fat (HF); and HF+5% BRBs. Body weight and diet consumption are recorded weekly until the mice are euthanized at 28 weeks of age. Mice fed with HF diets are found to significantly gain body weight over time. BRBs are not found to affect the development of obesity. Mice in the HF+BRBs group consume less food than the HF-only mice. HF+BRBs diets suppress uterine tumor initiation and promotion more than the HF-only diet by inhibiting cell proliferation. It also reduces HF-induced levels of plasma leptin and 17β-estradiol (E2). Urolithin A, a metabolite of BRBs, suppresses cell proliferation induced by leptin and E2.

CONCLUSION

BRBs are preventive in HF-mediated uterine tumorigenesis because they suppress cell growth and plasma leptin and E2 levels.

Leptin Receptor as a Potential Target to Inhibit Human Testicular Seminoma Growth

Although in past decades the adipokine leptin and its own receptor have been considered as significant cancer biomarkers, their potential involvement in human testicular seminoma growth and progression remains unexplored. Here, we showed that the expression of leptin and its receptor was significantly higher in human testicular seminoma compared with normal adult testis. Human seminoma cell line TCam-2 also expressed leptin along with the long and short isoforms of leptin receptor, and in response to leptin treatment showed enhanced activation of its downstream effectors. In line with these results, leptin stimulation significantly increased the proliferation and migration of TCam-2 cells. Treatment of TCam-2 cells with the peptide Leu-Asp-Phe-Ile (LDFI), a full leptin-receptor antagonist, completely reversed the leptin-mediated effects on cell growth and motility as well as reduced the expression of several leptin-induced target genes. More importantly, the in vivo xenograft experiments showed that LDFI treatment markedly decreased seminoma tumor growth. Interestingly, LDFI-treated tumors showed reduced levels of the proliferation marker Ki-67 as well as decreased expression of leptin-regulated genes. Taken together, these data identify, for the first time, leptin as a key factor able to affect testicular seminoma behavior, highlighting leptin receptor as a potential target for novel potential treatments in this type of cancer.

Stress as a Risk Factor for Substance Use Disorders: A Mini-Review of Molecular Mediators

The extant literature supports the role of stress in enhancing the susceptibility of drug abuse progressing to a substance use disorder diagnosis. However, the molecular mediators by which stress enhances the progression from cocaine abuse to cocaine use disorder via the mesolimbic pathway remain elusive. In this mini-review article, we highlight three mechanisms by which glucocorticoids (GCs) and the dopaminergic system interact. First, GCs upregulate tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine (DA) synthesis. Second, GCs downregulate monoamine-oxidase (MAO), an enzyme responsible for DA removal. Lastly, GCs are hypothesized to decrease DA reuptake, subsequently increasing synaptic DA. Based on these interactions, we review preclinical literature highlighting how stress modulates the mesolimbic pathway, including the ventral tegmental area (VTA) and nucleus accumbens (NAcs), to alter cocaine abuse-related effects. Taken together, stress enhances cocaine's abuse-related effects at multiple points along the VTA mesolimbic projection, and uniquely in the NAcs through a positive feedback type mechanism. Furthermore, we highlight future directions to elucidate the interaction between the prefrontal cortex (PFC) and key intermediaries including ΔFosB, cAMP response element binding protein (CREB) and cyclin-dependent kinase 5 (CDK5) to highlight possible mechanisms that underlie stress-induced acceleration of the progression to a cocaine use disorder diagnosis.

Gender-specific alteration of energy balance and circadian locomotor activity in the Crtc1 knockout mouse model of depression

Obesity and depression are major public health concerns, and there is increasing evidence that they share etiological mechanisms. CREB-regulated transcription coactivator 1 (CRTC1) participates in neurobiological pathways involved in both mood and energy balance regulation. Crtc1 ^-/- mice rapidly develop a depressive-like and obese phenotype in early adulthood, and are therefore a relevant animal model to explore possible common mechanisms underlying mood disorders and obesity. Here, the obese phenotype of male and female Crtc1 ^-/- mice was further characterized by investigating CRTC1's role in the homeostatic and hedonic regulation of food intake, as well as its influence on daily locomotor activity. Crtc1 ^-/- mice showed a strong gender difference in the homeostatic regulation of energy balance. Mutant males were hyperphagic and rapidly developed obesity on normal chow diet, whereas Crtc1 ^-/- females exhibited mild late-onset obesity without hyperphagia. Overeating of mutant males was accompanied by alterations in the expression of several orexigenic and anorexigenic hypothalamic genes, thus confirming a key role of CRTC1 in the central regulation of food intake. No alteration in preference and conditioned response for saccharine was observed in Crtc1 ^-/- mice, suggesting that mutant males' hyperphagia was not due to an altered hedonic regulation of food intake. Intriguingly, mutant males exhibited a hyperphagic behavior only during the resting (diurnal) phase of the light cycle. This abnormal feeding behavior was associated with a higher diurnal locomotor activity indicating that the lack of CRTC1 may affect circadian rhythmicity. Collectively, these findings highlight the male-specific involvement of CRTC1 in the central control of energy balance and circadian locomotor activity.

LKB1 as a Tumor Suppressor in Uterine Cancer: Mouse Models and Translational Studies

The LKB1 tumor suppressor was identified in 1998 as the gene mutated in the Peutz-Jeghers Syndrome (PJS), a hereditary cancer predisposition characterized by gastrointestinal polyposis and a high incidence of cancers, particularly carcinomas, at a variety of anatomic sites including the gastrointestinal tract, lung, and female reproductive tract. Women with PJS have a high incidence of carcinomas of the uterine corpus (endometrium) and cervix. The LKB1 gene is also somatically mutated in human cancers arising at these sites. Work in mouse models has highlighted the potency of LKB1 as an endometrial tumor suppressor and its distinctive roles in driving invasive and metastatic growth. These in vivo models represent tractable experimental systems for the discovery of underlying biological principles and molecular processes regulated by LKB1 in the context of tumorigenesis and also serve as useful preclinical model systems for experimental therapeutics. Here we review LKB1's known roles in mTOR signaling, metabolism, and cell polarity, with an emphasis on human pathology and mouse models relevant to uterine carcinogenesis, including cancers of the uterine corpus and cervix.

Pancancer modelling predicts the context-specific impact of somatic mutations on transcriptional programs

Pancancer studies have identified many genes that are frequently somatically altered across multiple tumour types, suggesting that pathway-targeted therapies can be deployed across diverse cancers. However, the same ‘actionable mutation' impacts distinct context-specific gene regulatory programs and signalling networks—and interacts with different genetic backgrounds of co-occurring alterations—in different cancers. Here we apply a computational strategy for integrating parallel (phospho)proteomic and mRNA sequencing data across 12 TCGA tumour data sets to interpret the context-specific impact of somatic alterations in terms of functional signatures such as (phospho)protein and transcription factor (TF) activities. Our analysis predicts distinct dysregulated transcriptional regulators downstream of somatic alterations in different cancers, and we validate the context-specific differential activity of TFs associated to mutant PIK3CA in isogenic cancer cell line models. These results have implications for the pancancer use of targeted drugs and potentially for the design of combination therapies.

Cancer genomic data sets contain a wealth of data that can be used to predict prognosis and further understand disease. Here, the authors integrate multiple genomics data types to identify transcriptional dysregulation in response to somatic mutations.

Cyclin D1 G870A polymorphism: Association with uterine leiomyoma risk and in silico analysis

Uterine leiomyoma (UL) is the most common benign tumor causing considerable morbidity during the reproductive years in women. Cyclin D1 (CCND1) is a cell cycle regulatory protein that is required for the G1 phase, and increased expression levels of this protein may affect tumorigenesis. The present study aimed to assess the possible effect of the CCND1 G870A polymorphism on UL susceptibility. A total of 154 women with UL and 197 healthy women who were age-, body mass index (BMI)- and ethnicity-matched were genotyped for the CCND1 G870A (rs9344) polymorphism using the polymerase chain reaction-restriction fragment length polymorphism method. The effects of G870A transition on the structure of mRNA and proteins of CCND1 was evaluated using bioinformatics tools. The frequency of the CCND1 870AA genotype was significantly higher in women with UL compared with the control subjects, and the risk of UL was 1.4-fold higher in women with the AA genotype when compared with the GG genotype before and after adjusting for age, BMI, and ethnicity [odds ratio (OR), 1.4; 95% confidence interval (CI), 1.1-2 (P=0.02)]. The frequency of CCND1 870GA genotype was not significantly different between the two groups. The frequency of the CCND1 870A allele was significantly higher in the women with UL when compared with the control subjects (57 vs. 48%; P=0.02). The in silico analysis revealed that the G870A transition may fundamentally alter the structure of the CCND1-mRNA. Thus, the CCND1 870AA genotype was associated with UL susceptibility in a sample of women from the southeast of Iran.

The molecular mechanism of action of superactive human leptin antagonist (SHLA) and quadruple leptin mutein Lan-2 on human ovarian epithelial cell lines

Introduction

A number of leptin receptor antagonists have been synthesised for therapeutic use, with pre-clinical tests suggesting their future use in anticancer therapy. To our knowledge, there are no data concerning the possible application of leptin receptor blockers in ovarian cancer.

Methods

In this study, we evaluated two leptin receptor antagonists: superactive human leptin antagonist (SHLA) and quadruple leptin mutein, Lan-2 (L39A/D40A/F41A/I42A), on cell proliferation (Alamar Blue test, BrdU assay), cell cycle gene (qPCR) and protein expression (Western blot) and cell signalling pathways (Western blot) in three different types of cell lines: OVCAR-3, CaOV-3 and HOSEpiC.

Results

Both receptor blockers had no effect on non-cancerous HOSEpiC cell line proliferation; however, both reversed the stimulatory effect of leptin on CaOV-3 cell line proliferation to control levels and to below control levels in OVCAR-3 cells. In metastatic carcinoma CaOV-3, both ObR antagonists had an inhibitory effect on the cdk2/cyclin D1 complex, while in serous carcinoma, OVCAR-3, they only had an effect on cdk2 and cdk4 protein expression. SHLA had an inhibitory effect on all investigated signalling pathways in OVCAR-3, while only on Stat3 in CaOV-3. Lan-2 had an inhibitory effect on Stat3 and ERK1/2 in CaOV-3, while in OVCAR-3 it only affected Akt protein phosphorylation.

Conclusion

Based on these results, we conclude that SHLA and Lan-2 are promising leptin receptor inhibitors which could be used to block leptin activity, eliminating its negative effects on activities related to carcinogenesis. However, the selection of a specific antagonist should be related to tumour type.

Leptin-Induced JAK/STAT Signaling and Cancer Growth

Growth factor and cytokine signaling can influence the development of several cancer types. One of the key players in the development of cancer is the Janus kinas (JAK) signal transducer of activators of transcription (STAT) signaling pathway. The majority of growth factors and cytokine interactions with their membrane-bound receptors trigger JAK-STAT activation. The influential relationship between obesity and cancer is a fact. However, there is a complex sequence of events contributing to the regulation of this mechanism to promote tumor growth, yet to be fully elucidated. The JAK-STAT pathway is influenced by obesity-associated changes that have been shown to impact cancer growth and progression. This intricate process is highly regulated by a vast array of adipokines and cytokines that exert their pleiotropic effects on cancer cells to enhance metastasis to distant target sites. Leptin is a cytokine, or more precise, an adipokine secreted mainly by adipose tissue that requires JAK-STAT activation to exert its biological functions. Leptin is the central regulator of energy balance and appetite. Leptin binding to its receptor OB-R in turn activates JAK-STAT, which induces proliferation, angiogenesis, and anti-apoptotic events in normal cells and malignant cells expressing the receptor. Leptin also induces crosstalk with Notch and IL-1 (NILCO), which involves other angiogenic factors promoting tumor growth. Therefore, the existence of multiple novel classes of therapeutics that target the JAK/STAT pathway has significant clinical implications. Then, the identification of the signaling networks and factors that regulate the obesity-cancer link to which potential pharmacologic interventions can be implemented to inhibit tumor growth and metastasis. In this review, we will discuss the specific relationship between leptin-JAK-STAT signaling and cancer.

Leptin augments recruitment of IRF-1 and CREB to thrombospondin-1 gene promoter in vascular smooth muscle cells in vitro

We previously reported that high pathophysiological concentrations of leptin, the adipocyte-secreted peptide, upregulate the expression of a potent proatherogenic matricellular protein, thrombospondin-1 (TSP-1), in vascular smooth muscle cells. Moreover, this regulation was found to occur at the level of transcription; however, the underlying molecular mechanisms remain unknown. The goal of the present study was to investigate the specific transcriptional mechanisms that mediate upregulation of TSP-1 expression by leptin. Primary human aortic smooth muscle cell cultures were transiently transfected with different TSP-1 gene (THBS1) promoter-linked luciferase reporter constructs, and luciferase activity in response to leptin (100 ng/ml) was assessed. We identified a long THBS1 promoter (-1270/+750) fragment with specific leptin response elements that are required for increased TSP-1 transcription by leptin. Promoter analyses, protein/DNA array and gel shift assays demonstrated activation and association of transcription factors, interferon regulatory factor-1 (IRF-1) and cAMP response element-binding protein (CREB), to the distal fragment of the THBS1 promoter in response to leptin. Supershift, chromatin immunoprecipitation, and coimmunoprecipitation assays revealed formation of a single complex between IRF-1 and CREB in response to leptin; importantly, recruitment of this complex to the THBS1 promoter mediated leptin-induced TSP-1 transcription. Finally, binding sequence decoy oligomer and site-directed mutagenesis revealed that regulatory elements for both IRF-1 (-1019 to -1016) and CREB (-1198 to -1195), specific to the distal THBS1 promoter, were required for leptin-induced TSP-1 transcription. Taken together, these findings demonstrate that leptin promotes a cooperative association between IRF-1 and CREB on the THBS1 promoter driving TSP-1 transcription in vascular smooth muscle cells.

Activated FXR Inhibits Leptin Signaling and Counteracts Tumor-promoting Activities of Cancer-Associated Fibroblasts in Breast Malignancy

Cancer-associated fibroblasts (CAFs), the principal components of the tumor stroma, play a central role in cancer development and progression. As an important regulator of the crosstalk between breast cancer cells and CAFs, the cytokine leptin has been associated to breast carcinogenesis. The nuclear Farnesoid X Receptor-(FXR) seems to exert an oncosuppressive role in different tumors, including breast cancer. Herein, we demonstrated, for the first time, that the synthetic FXR agonist GW4064, inhibiting leptin signaling, affects the tumor-promoting activities of CAFs in breast malignancy. GW4064 inhibited growth, motility and invasiveness induced by leptin as well as by CAF-conditioned media in different breast cancer cell lines. These effects rely on the ability of activated FXR to increase the expression of the suppressor of the cytokine signaling 3 (SOCS3) leading to inhibition of leptin-activated signaling and downregulation of leptin-target genes. In vivo xenograft studies, using MCF-7 cells alone or co-injected with CAFs, showed that GW4064 administration markedly reduced tumor growth. Interestingly, GW4064-treated tumors exhibited decreased levels of leptin-regulated proteins along with a strong staining intensity for SOCS3. Thus, FXR ligands might represent an emerging potential anti-cancer therapy able to block the tumor supportive role of activated fibroblasts within the breast microenvironment.

3-(Dipropylamino)-5-hydroxybenzofuro[2,3-f]quinazolin-1(2H)-one (DPA-HBFQ-1) plays an inhibitory role on breast cancer cell growth and progression

A series of unknown 3-(alkyl(dialkyl)amino)benzofuro[2,3-f]quinazolin-1(2H)-ones 4-17 has been synthesized as new ellipticine analogs, in which the carbazole moiety and the pyridine ring were replaced by a dibenzofuran residue and a pyrimidine ring, respectively. The synthesis of these benzofuroquinazolinones 4-17 was performed in a simple one-pot reaction using 3-aminodibenzofuran or its 2-methoxy derivative, as starting materials. From 3-(dipropylamino)-5-methoxybenzofuro[2,3-f] quinazolin-1(2H)-one (13), we prepared 3-(dipropylamino)-5-hydroxybenzofuro[2,3-f]quinazolin-1(2H)-one (18), referred to as DPA-HBFQ-1. The cytotoxic activities of all the synthesized compounds, tested in different human breast cancer cell lines, revealed that DPA-HBFQ-1 was the most active compound. In particular, the latter was able to inhibit anchorage-dependent and -independent cell growth and to induce apoptosis in estrogen receptor alpha (ERα)-positive and -negative breast cancer cells. It did not affect proliferation and apoptotic responses in MCF-10A normal breast epithelial cells. The observed effects have been ascribed to an enhanced p21(Cip1/WAF1) expression in a p53-dependent manner of tumor suppressor and to a selective inhibition of human topoisomerase II. In addition, DPA-HBFQ-1 exerted growth inhibitory effects also in other cancer cell lines, even though with a lower cytotoxic activity. Our results indicate DPA-HBFQ-1 as a good candidate to be useful as cancer therapeutic agent, particularly for breast cancer.

Phosphorylation of STAT3 mediates the induction of cyclooxygenase-2 by cortisol in the human amnion at parturition

The induction of cyclooxygenase-2 (COX-2) and subsequent production of prostaglandin E2 (PGE2) by cortisol in the amnion contrast with the effect of cortisol on most other tissues, but this proinflammatory effect of cortisol may be a key event in human parturition (labor). We evaluated the underlying mechanism activated by cortisol in primary human amnion fibroblasts. Exposure of the amnion fibroblasts to cortisol led to the activation of the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway, which induced the phosphorylation of the kinase SRC and STAT3 (signal transducer and activator of transcription 3). STAT3 interacted with the glucocorticoid receptor (GR) and the transcription factor CREB-1 (cAMP response element-binding protein 1) at the promoter of the gene encoding COX-2, which promoted the production of the secreted prostaglandin PGE2. PGE2 activates the prostaglandin receptors EP2 and EP4, which stimulate cAMP-PKA signaling. Thus, cortisol reinforced the activation of cAMP-PKA signaling through an SRC-STAT3-COX-2-PGE2-mediated feedback loop. Inhibiting STAT3, SRC, or the cAMP-PKA pathway attenuated the cortisol-stimulated induction of COX-2 and PGE2 production in amnion fibroblasts. In human amnion tissue, the amount of phosphorylated STAT3 correlated positively with that of cortisol, COX-2, and PGE2, and all were more abundant in tissue obtained after active labor than in tissue obtained from cesarean surgeries in the absence of labor. These results indicated that the coordinated recruitment of STAT3, CREB-1, and GR to the promoter of the gene encoding COX-2 contributes to the feed-forward induction of COX-2 activity and prostaglandin synthesis in the amnion during parturition.

Leptin exerts proliferative and anti-apoptotic effects on goose granulosa cells through the PI3K/Akt/mTOR signaling pathway

Leptin was known as a pivotal regulator for the control of food intake and energy expenditure. However, leptin has also been found to be involved in the regulation of female reproductive system through interactions with pathways in the hypothalamic-hypophyseal axis and direct action at the ovarian level. In the present study, granulosa cells from goose ovarian preovulatory (F1-F3) follicles were cultured with leptin (0, 1, 10 or 100ng/ml). The proliferative and anti-apoptotic actions of leptin in granulosa cells were revealed by CCK-8, BrdU and TUNEL assays. Quantitative real-time PCR and Western blot analyses further indicated that leptin treatment led to increased expression of cyclin D1, cyclin D2, cyclin D3 and bcl-2, and decreased expression of p21 and caspase-3. The effects were involved in the activation of the PI3K/Akt/mTOR signaling pathway, as leptin treatment enhanced the expression of PI3K, Akt1, Akt2, Raptor, mTOR, S6K and p-S6K. Moreover, blockade of the PI3K/Akt/mTOR pathway attenuated the influences of leptin on proliferation and apoptosis of granulosa cells, considering that activated factors by leptin were inhibited in the presence of either 20μM LY294002 (a PI3K inhibitor) or 10μM rapamycin (an mTOR inhibitor). In addition, leptin had a modulatory effect on the expression of its receptor at the transcriptional and translational levels, and blockade of PI3K/Akt/mTOR inhibited both basal and leptin-induced Lepr gene and protein expression. These findings suggest that leptin exerts its proliferative and anti-apoptotic effects on goose granulosa cells through the PI3K/Akt/mTOR signaling pathway via interaction with its receptor.

Estrogen receptor-α drives adiponectin effects on cyclin D1 expression in breast cancer cells

Obesity is a risk factor for breast cancer, largely due to altered expression of various adipocytokines. As it concerns adiponectin, there are not univocal results regarding its role in breast cancer occurrence and progression. Here, we demonstrate that in animals injected with human estrogen receptor (ER)-α-negative MDA-MB-231 cells pretreated with adiponectin (1 and 5 µg/ml), a significant reduction (60 and 40%, respectively) in tumor volume is observed, whereas an increased tumor growth (54 and 109%, respectively) is evidenced in the animals receiving human ER-α-positive MCF-7 cells. Moreover, cyclin D1 (CD1) mRNA and protein levels are decreased in MDA-MB-231 cells, whereas they are up-regulated in ER-α-positive cells by adiponectin. These findings fit with the opposite effects of adiponectin on CD1 promoter: 0.44- and 0.34-fold decrease in MDA-MB-231 cells and 0.63- and 0.95-fold increase in MCF-7 cells, treated with 1 and 5 µg/ml, respectively. Functional studies indicate that these effects are mediated by the specific protein 1 motif located in the CD1 promoter. In the absence of ER-α, the adiponectin-mediated down-regulation of CD1 involves the recruitment of corepressors. In the presence of ER-α, the adiponectin-induced expression of CD1 requires the involvement of an activator complex. In conclusion, we propose that a possible mechanism through which adiponectin differently affects breast cancer growth is the opposite modulation of CD1 levels accordingly to ER-α expression.

Leptin signaling molecular actions and drug target in hepatocellular carcinoma

Previous reports indicate that over 13 different tumors, including hepatocellular carcinoma (HCC), are related to obesity. Obesity-associated inflammatory, metabolic, and endocrine mediators, as well as the functioning of the gut microbiota, are suspected to contribute to tumorigenesis. In obese people, proinflammatory cytokines/chemokines including tumor necrosis factor-alpha, interleukin (IL)-1 and IL-6, insulin and insulin-like growth factors, adipokines, plasminogen activator inhibitor-1, adiponectin, and leptin are found to play crucial roles in the initiation and development of cancer. The cytokines induced by leptin in adipose tissue or tumor cells have been intensely studied. Leptin-induced signaling pathways are critical for biological functions such as adiposity, energy balance, endocrine function, immune reaction, and angiogenesis as well as oncogenesis. Leptin is an activator of cell proliferation and anti-apoptosis in several cell types, and an inducer of cancer stem cells; its critical roles in tumorigenesis are based on its oncogenic, mitogenic, proinflammatory, and pro-angiogenic actions. This review provides an update of the pathological effects of leptin signaling with special emphasis on potential molecular mechanisms and therapeutic targeting, which could potentially be used in future clinical settings. In addition, leptin-induced angiogenic ability and molecular mechanisms in HCC are discussed. The stringent binding affinity of leptin and its receptor Ob-R, as well as the highly upregulated expression of both leptin and Ob-R in cancer cells compared to normal cells, makes leptin an ideal drug target for the prevention and treatment of HCC, especially in obese patients.

Selective CREB-dependent cyclin expression mediated by the PI3K and MAPK pathways supports glioma cell proliferation

The cyclic-AMP response element binding (CREB) protein has been shown to have a pivotal role in cell survival and cell proliferation. Transgenic rodent models have revealed a role for CREB in higher-order brain functions, such as memory and drug addiction behaviors. CREB overexpression in transgenic animals imparts oncogenic properties on cells in various tissues, and aberrant CREB expression is associated with tumours. It is the central position of CREB, downstream from key developmental and growth signalling pathways, which gives CREB this ability to influence a spectrum of cellular activities, such as cell survival, growth and differentiation, in both normal and cancer cells. We show that CREB is highly expressed and constitutively activated in patient glioma tissue and that this activation closely correlates with tumour grade. The mechanism by which CREB regulates glioblastoma (GBM) tumour cell proliferation involves activities downstream from both the mitogen-activated protein kinase and phosphoinositide 3-kinase (PI3K) pathways that then modulate the expression of three key cell cycle factors, cyclin B, D and proliferating cell nuclear antigen (PCNA). Cyclin D1 is highly CREB-dependent, whereas cyclin B1 and PCNA are co-regulated by both CREB-dependent and -independent mechanisms. The precise regulatory network involved appears to differ depending on the tumour-suppressor phosphatase and tensin homolog status of the GBM cells, which in turn allows CREB to regulate the activity of the PI3K itself. Given that CREB sits at the hub of key cancer cell signalling pathways, understanding the role of glioma-specific CREB function may lead to improved novel combinatorial anti-tumour therapies, which can complement existing PI3K-specific drugs undergoing early phase clinical trials.

Oncogenic role and therapeutic target of leptin signaling in colorectal cancer

INTRODUCTION

Obesity is characterized by high secretion of several cytokines from adipose tissue and is a recognized risk factor for many cancers. Among these cytokines, leptin mainly produced by adipose tissue and cancer cells is the most studied adipokine. Leptin is an activator of cell proliferation, an antiapoptotic molecule and inducer of cancer stem cells in many cell types, and its critical roles in obesity-related tumorigenesis are based on its oncogenic, mitogenic, pro-inflammatory and pro-angiogenic actions.

AREAS COVERED

These leptin-induced signals and action are critical for their biological effects on energy balance, adiposity, endocrine systems, immunity, angiogenesis as well as oncogenesis. This review focuses on the up-to-date knowledge on the oncogenic role of leptin signaling, clinical significance and specific drug target development in colorectal cancer (CRC). Additionally, leptin-induced angiogenic ability and molecular mechanisms in CRC cells are discussed.

EXPERT OPINION

Stringent binding affinity of leptin/Ob-R and overexpression of leptin/Ob-R and their targets in cancer cells make it a unique drug target for prevention and treatment of CRC, particularly in obesity colorectal patients.

Leptin induces hippocampal synaptogenesis via CREB-regulated microRNA-132 suppression of p250GAP

Leptin acts in the hippocampus to enhance cognition and reduce depression and anxiety. Cognitive and emotional disorders are associated with abnormal hippocampal dendritic spine formation and synaptogenesis. Although leptin has been shown to induce synaptogenesis in the hypothalamus, its effects on hippocampal synaptogenesis and the mechanism(s) involved are not well understood. Here we show that leptin receptors (LepRs) are critical for hippocampal dendritic spine formation in vivo because db/db mice lacking the long form of the leptin receptor (LepRb) have reduced spine density on CA1 and CA3 neurons. Leptin promotes the formation of mature spines and functional glutamate synapses on hippocampal pyramidal neurons in both dissociated and slice cultures. These effects are blocked by short hairpin RNAs specifically targeting the LepRb and are absent in cultures from db/db mice. Activation of the LepR leads to cAMP response element-binding protein (CREB) phosphorylation and initiation of CREB-dependent transcription via the MAPK kinase/Erk pathway. Furthermore, both Mek/Erk and CREB activation are required for leptin-induced synaptogenesis. Leptin also increases expression of microRNA-132 (miR132), a well-known CREB target, which is also required for leptin-induced synaptogenesis. Last, leptin suppresses the expression of p250GAP, a miR132 target, and this suppression is obligatory for leptin's effects as is the downstream target of p250GAP, Rac1. LepRs appear to be critical in vivo as db/db mice have lowered hippocampal miR132 levels and elevated p250GAP expression. In conclusion, we identify a novel signaling pathway by which leptin increases synaptogenesis through inducing CREB transcription and increasing microRNA-mediated suppression of p250GAP activity, thus removing a known inhibitor of Rac1-stimulated synaptogenesis.

Estrogen receptor beta as a novel target of androgen receptor action in breast cancer cell lines

INTRODUCTION

The two isoforms of estrogen receptor (ER) alpha and beta play opposite roles in regulating proliferation and differentiation of breast cancers, with ER-alpha mediating mitogenic effects and ER-beta acting as a tumor suppressor. Emerging data have reported that androgen receptor (AR) activation inhibits ER-positive breast cancer progression mainly by antagonizing ER-alpha signaling. However, to date no studies have specifically evaluated a potential involvement of ER-beta in the inhibitory effects of androgens.

METHODS

ER-beta expression was examined in human breast cancer cell lines using real-time PCR, Western blotting and small interfering RNA (siRNA) assays. Mutagenesis studies, electromobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) analysis were performed to assess the effects of mibolerone/AR on ER-beta promoter activity and binding.

RESULTS

In this study, we demonstrate that mibolerone, a synthetic androgen ligand, up-regulates ER-beta mRNA and protein levels in ER-positive breast cancer cells. Transient transfection experiments, using a vector containing the human ER-beta promoter region, show that mibolerone increases basal ER-beta promoter activity. Site-directed mutagenesis and deletion analysis reveal that an androgen response element (ARE), TGTTCT motif located at positions -383 and -377, is critical for mibolerone-induced ER-beta up-regulation in breast cancer cells. This occurs through an increased recruitment of AR to the ARE site within the ER-beta promoter region, along with an enhanced occupancy of RNA polymerase II. Finally, silencing of ER-beta gene expression by RNA interference is able to partially reverse the effects of mibolerone on cell proliferation, p21 and cyclin D1 expression.

CONCLUSIONS

Collectively, these data provide evidence for a novel mechanism by which activated AR, through an up-regulation of ER-beta gene expression, inhibits breast cancer cell growth.

FOXA1 promotes tumor cell proliferation through AR involving the Notch pathway in endometrial cancer

Background

Increasing evidence suggests that forkhead box A1 (FOXA1) is frequently dysregulated in many types of human cancers. However, the exact function and mechanism of FOXA1 in human endometrial cancer (EC) remains unclear.

Methods

FOXA1 expression, androgen receptor (AR) expression, and the relationships of these two markers with clinicopathological factors were determined by immunohistochemistry analysis. FOXA1 and AR were up-regulated by transient transfection with plasmids, and were down-regulated by transfection with siRNA or short hairpin RNA (shRNA). The effects of FOXA1 depletion and FOXA1 overexpression on AR-mediated transcription as well as Notch pathway and their impact on EC cell proliferation were examined by qRT-PCR, western blotting, co-immunoprecipitation, ChIP-PCR, MTT, colony-formation, and xenograft tumor–formation assays.

Results

We found that the expression of FOXA1 and AR in ECs was significantly higher than that in a typical hyperplasia and normal tissues. FOXA1 expression was significantly correlated with AR expression in clinical tissues. High FOXA1 levels positively correlated with pathological grade and depth of myometrial invasion in EC. High AR levels also positively correlated with pathological grade in EC. Moreover, the expression of XBP1, MYC, ZBTB16, and UHRF1, which are downstream targets of AR, was promoted by FOXA1 up-regulation or inhibited by FOXA1 down-regulation. Co-immunoprecipitation showed that FOXA1 interacted with AR in EC cells. ChIP-PCR assays showed that FOXA1 and AR could directly bind to the promoter and enhancer regions upstream of MYC. Mechanistic investigation revealed that over-expression of Notch1 and Hes1 proteins by FOXA1 could be reversed by AR depletion. In addition, we showed that down-regulation of AR attenuated FOXA1-up-regulated cell proliferation. However, AR didn’t influence the promotion effect of FOXA1 on cell migration and invasion. In vivo xenograft model, FOXA1 knockdown reduced the rate of tumor growth.

Conclusions

These results suggest that FOXA1 promotes cell proliferation by AR and activates Notch pathway. It indicated that FOXA1 and AR may serve as potential gene therapy in EC.

Serum leptin, adiponectin and endometrial cancer risk in Chinese women

Objective

To investigate the relationship between serum concentrations of leptin or adiponectin, and endometrial carcinoma in Chinese women.

Methods

We conducted a case-control study of a total of 516 Chinese women to detect the relationships between serum concentrations of leptin or adiponectin, and endometrial carcinoma in Chinese women. The study subject constituted 206 cases of endometrial cancer and 310 normal controls.

Results

Patients with endometrial carcinoma had higher serum leptin concentrations than controls (28.8±2.2 ug/L vs. 19.8±1.4 ug/L; p<0.001). The adiponectin levels in patients were lower than in controls with borderline statistical significance (2,330.7±180.5 ug/L vs. 2,583.9±147.2 ug/L; p=0.078). Logistic regression analysis confirmed the associations between leptin or adiponectin, and endometrial carcinoma after adjustment for age, body mass index, fasting insulin, serum glucose, cholesterol, triglycerides, and high-density lipoprotein cholesterol (odds ratio for the top tertile vs. the bottom tertile: leptin 2.05; 95% confidence interval [CI], 1.28 to 3.29; p<0.001; adiponectin 0.52; 95% CI, 0.32 to 0.83; p<0.001).

Conclusion

Increased leptin or decreased adiponectin levels are associated with endometrial carcinoma.

Leptin promotes human endometrial carcinoma cell proliferation by enhancing aromatase (P450arom) expression and estradiol formation

OBJECTIVE

Leptin, a multifunctional peptide hormone encoded by the obese (ob) gene, plays an important role in modulating lipid metabolism and energy equilibrium. Leptin reportedly acts as a cell growth factor and enhances the proliferation of various tumors. We investigated the effect of leptin on aromatase (P450arom) expression and estradiol (E2) formation in a model of endometrial carcinoma.

STUDY DESIGN

We established a co-culture model of endometrial fibroblasts and the Ishikawa endometrial carcinoma cell line. P450arom mRNA and protein expression were measured with RT-PCR and immunoblotting, respectively, before and after leptin treatment. The effect of leptin on estradiol formation in endometrial carcinoma cells was also detected with a radioimmunological method.

RESULTS

P450arom mRNA expression was increased in co-cultures treated with 100 ng/ml leptin (P<0.01). Estradiol synthesis was induced when androstenedione was added to the culture medium, and significantly higher estradiol concentration was observed in co-cultures treated with 100 ng/ml leptin,

CONCLUSIONS

Leptin is an important component of the microenvironment and stimulates endometrial carcinoma cell proliferation via enhancing P450arom expression and estradiol synthesis.

Cancer risk and PCOS

Women with polycystic ovary syndrome (PCOS) have a 2.7-fold increased risk for developing endometrial cancer. A major factor for this increased malignancy risk is prolonged exposure of the endometrium to unopposed estrogen that results from anovulation. Additionally, secretory endometrium of some women with PCOS undergoing ovulation induction or receiving exogenous progestin exhibits progesterone resistance accompanied by dysregulation of gene expression controlling steroid action and cell proliferation. Endometrial surveillance includes transvaginal ultrasound and/or endometrial biopsy to assess thickened endometrium, prolonged amenorrhea, unopposed estrogen exposure or abnormal vaginal bleeding. Medical management for abnormal vaginal bleeding or endometrial hyperplasia consists of estrogen-progestin oral contraceptives, cyclic or continuous progestins or a levonorgestrel-releasing (Mirena) intrauterine device. Lifestyle modification with caloric restriction and exercise is appropriate to treat obesity as a concomitant risk factor for developing endometrial disease. An increased risk of ovarian cancer may also exist in some women with PCOS. There are strong data to suggest that oral contraceptive use is protective against ovarian cancer and increases with the duration of therapy. The mechanism of this protection may be through suppression of gonadotropin secretion rather than the prevention of "incessant ovulation". There is no apparent association of PCOS with breast cancer, although the high prevalence of metabolic dysfunction from obesity is a common denominator for both conditions. Recent data suggest that the use of metformin may be protective for both endometrial and breast cancer. There are insufficient data to evaluate any association between PCOS and vaginal, vulvar and cervical cancer or uterine leiomyosarcoma.

Control of energy balance by hypothalamic gene circuitry involving two nuclear receptors, neuron-derived orphan receptor 1 and glucocorticoid receptor

Nuclear receptors (NRs) regulate diverse physiological processes, including the central nervous system control of energy balance. However, the molecular mechanisms for the central actions of NRs in energy balance remain relatively poorly defined. Here we report a hypothalamic gene network involving two NRs, neuron-derived orphan receptor 1 (NOR1) and glucocorticoid receptor (GR), which directs the regulated expression of orexigenic neuropeptides agouti-related peptide (AgRP) and neuropeptide Y (NPY) in response to peripheral signals. Our results suggest that the anorexigenic signal leptin induces NOR1 expression likely via the transcription factor cyclic AMP response element-binding protein (CREB), while the orexigenic signal glucocorticoid mobilizes GR to inhibit NOR1 expression by antagonizing the action of CREB. Also, NOR1 suppresses glucocorticoid-dependent expression of AgRP and NPY. Consistently, relative to wild-type mice, NOR1-null mice showed significantly higher levels of AgRP and NPY and were less responsive to leptin in decreasing the expression of AgRP and NPY. These results identify mutual antagonism between NOR1 and GR to be a key rheostat for peripheral metabolic signals to centrally control energy balance.

Cyclic AMP-response element regulated cell cycle arrests in cancer cells

Recently, we have demonstrated that trichosanthin (TCS), a promising agent for the treatment of cervical adenocarcinoma, inhibited HeLa cell proliferation through the PKC/MAPK/CREB signal pathway. Furthermore, TCS down-regulated Bcl-2 expression was abrogated by a decoy oligonucleotide (OGN) to the cyclic AMP-responsive element (CRE). The decoy OGN blocked the binding of CRE-binding protein (CREB) to Bcl-2. These results suggested that CRE-mediated gene expression may play a pivotal role in HeLa cell proliferation. However, little is known about the effect of TCS on cell cycle arrests, particularly, whether the genes involved in cell cycle were regulated by CRE. Our present study shows that the arrests of S, G1 and G2/M phases were accompanied by the significant down-regulation of cyclin A, D1 and CDK 2, 4 in HeLa cells, cyclin D1, E and CDK 2, 4 in Caski and C33a cells, and cyclin A, B1, E and CDK 2 in SW1990 cells. However, the cell cycle arrests were reversed via the significant up-regulation of cyclin A and D1, by the combined treatment of TCS and CRE. In conclusion, these data demonstrate for the first time that specific cell cycle arrests in cancer cells can be induced by TCS by inhibiting the binding of CREB to CRE on genes related to cell proliferation.

Leptin stimulation of cell cycle and inhibition of apoptosis gene and protein expression in OVCAR-3 ovarian cancer cells

The OVCAR-3 cell line expressing the long (ObRb) and short (ObRt) isoforms of leptin receptor mRNA was used to analyze the effect of leptin on the expression of selected genes and proteins involved in the cell cycle and apoptosis. OVCAR-3 cells were exposed to 2, 20, 40, and 100 ng/ml of leptin. Cell proliferation was determined using the alamarBlue cell viability test and flow cytometry. Apoptosis was measured using a cellular DNA fragmentation ELISA kit. The expression of selected cell cycle and apoptosis genes was evaluated by real-time PCR and confirmed by western blot. The stimulatory action of leptin on cell proliferation was observed as an increase in cells in the S and G2/M phases. Up-regulation of genes responsible for inducing cell proliferation and suppression of genes responsible for inhibition of proliferation were noted. Western blots revealed increased expression of cyclins D and A and inhibition of p21WAF1/CIP1 protein expression by leptin. Inhibition of DNA fragmentation was observed under all leptin doses. Suppression of genes involved in the extrinsic and intrinsic apoptotic pathway was observed. Western blots illustrated decreased Bad, TNFR1, and caspase 6 protein expression in response to leptin treatment. Leptin promotes ovarian cancer cell line growth by up-regulating genes and proteins responsible for inducing cell proliferation as well as down-regulating pro-apoptotic genes and proteins in apoptotic pathways. Results of this study warrant examining the relationship between the risk of ovarian cancer and elevated leptin levels in obese women.

Leptin induces cyclin D1 expression and proliferation of human nucleus pulposus cells via JAK/STAT, PI3K/Akt and MEK/ERK pathways

Increasing evidence suggests that obesity and aberrant proliferation of nucleus pulposus (NP) cells are associated with intervertebral disc degeneration. Leptin, a hormone with increased circulating level in obesity, has been shown to stimulate cell proliferation in a tissue-dependent manner. Nevertheless, the effect of leptin on the proliferation of human NP cells has not yet been demonstrated. Here, we show that leptin induced the proliferation of primary cultured human NP cells, which expressed the leptin receptors OBRa and OBRb. Induction of NP cell proliferation was confirmed by CCK8 assay and immunocytochemistry and Real-time PCR for PCNA and Ki-67. Mechanistically, leptin induced the phosphorylation of STAT3, Akt and ERK1/2 accompanied by the upregulation of cyclin D1. Pharmacological inhibition of JAK/STAT3, PI3K/Akt or MEK/ERK signaling by AG490, Wortmannin or U0126, respectively, reduced leptin-induced cyclin D1 expression and NP cell proliferation. These experiments also revealed an intricate crosstalk among these signaling pathways in mediating the action of leptin. Taken together, we show that leptin induces human NP cell cyclin D1 expression and proliferation via activation of JAK/STAT3, PI3K/Akt or MEK/ERK signaling. Our findings may provide a novel molecular mechanism that explains the association between obesity and intervertebral disc degeneration.

Bergapten induces ER depletion in breast cancer cells through SMAD4-mediated ubiquitination

ERα function is crucial for the development of normal mammary gland as well as in the process of progression of breast cancer cells. Signals that target receptor levels contribute to regulate estrogens effects in the cells. An intricate cross-regulation has been documented between ERα and TGF-β down-stream molecules: SMAD2, SMAD3, and SMAD4, that can bind ERα and regulate their signaling. Thus, identification of natural anticancer drugs able to influence the latter molecule might provide alternative choices for breast cancer treatment. Taking into account our previous published data we wanted to study the effect of 5-Methoxypsoralen (bergapten) on ERα and on TGF-β pathway. We reported that bergapten, a coumarin containing compound, effectively depletes ERα in MCF-7 breast cancer sensitive cells and in tamoxifen-resistant clone. The decrease of ERα protein after bergapten treatment results from the ubiquitine-proteasome pathway as demonstrated by the use of MG-132. IP experiments with ER antibody, demonstrated that the protein has physical interaction with SMAD4 and poly-ubiquitine and the amount of ubiquitinated receptor, linked to SMAD4, is greater under bergapten. The crucial role played by SMAD4, in this process, emerges from the observation that in breast cancer cells, silencing of SMAD4, resulted in increased expression of endogenous ERα in both control and bergapten-treated cells, compared to wild- type cells. The same results were confirmed in siRNA TGF-β RII cells. The results suggest a novel negative regulation of ERα by TGF-β/SMAD4 in breast cancer cells and indicate that the SMAD4 protein is involved in the degradation of ERα induced by bergapten. We propose that bergapten may efficiently act as a natural antitumoral agent, able to deplete ERα from breast cancer tamoxifen-sensitive and resistant cells, thereby retraining the effect of membrane signals targeting ERα and in such way its mitogenic potentiality.

Oldenlandia diffusa extracts exert antiproliferative and apoptotic effects on human breast cancer cells through ERα/Sp1-mediated p53 activation

Breast cancer is the most frequent tumor and a major cause of death among women. Estrogens play a crucial role in breast tumor growth, which is the rationale for the use of hormonal antiestrogen therapies. Unfortunately, not all therapeutic modalities are efficacious and it is imperative to develop new effective antitumoral drugs. Oldenlandia diffusa (OD) is a well-known medicinal plant used to prevent and treat many disorders, especially cancers. The aim of this study was to investigate the effects of OD extracts on breast cancer cell proliferation. We observed that OD extracts strongly inhibited anchorage-dependent and -independent cell growth and induced apoptosis in estrogen receptor alpha (ERα)-positive breast cancer cells, whereas proliferation and apoptotic responses of MCF-10A normal breast epithelial cells were unaffected. Mechanistically, OD extracts enhance the tumor suppressor p53 expression as a result of an increased binding of ERα/Sp1 complex to the p53 promoter region. Finally, we isolated ursolic and oleanolic acids as the bioactive compounds able to upregulate p53 expression and inhibit breast cancer cell growth. These acids were greatly effective in reducing tamoxifen-resistant growth of a derivative MCF-7 breast cancer cell line resistant to the antiestrogen treatment. Our results evidence how OD, and its bioactive compounds, exert antiproliferative and apoptotic effects selectively in ERα-positive breast cancer cells, highlighting the potential use of these herbal extracts as breast cancer preventive and/or therapeutic agents.

Aromatase up-regulation, insulin and raised intracellular oestrogens in men, induce adiposity, metabolic syndrome and prostate disease, via aberrant ER-α and GPER signalling

For some years now, reduced testosterone levels have been related to obesity, insulin resistance, type 2 diabetes, heart disease, benign prostatic hypertrophy and even prostate cancer--often considered guilty more by association, than actual cause--with little attention paid to the important role of increased intracellular oestrogen, in the pathogenesis of these chronic diseases. In the final stage of the steroidogenic cascade, testosterone is metabolised to oestradiol by P450 aromatase, in the cytoplasm of adipocytes, breast cells, endothelial cells and prostate cells, to increase intracellular oestradiol concentration at the expense of testosterone. It follows therefore, that any compound that up-regulates aromatase, or any molecule that mimics oestrogen, will not only increase the activation of the mainly proliferative, classic ER-α, oestrogen receptors to induce adipogenesis and growth disorders in oestrogen-sensitive tissues, but also activate the recently identified transmembrane G protein-coupled oestrogen receptors (GPER), and deleteriously alter important intracellular signalling sequences, that promote mitogenic growth and endothelial damage. This paper simplifies how stress, xeno-oestrogens, poor dietary choices and reactive toxins up-regulate aromatase to increase intracellular oestradiol production; how oestradiol in combination with leptin and insulin cause insulin resistance and leptin resistance through aberrant serine phosphorylation; how the increased oestradiol, insulin and leptin stimulate rapid, non-genomic G protein-coupled phosphorylation cascades, to increase fat deposition and create the vasoconstrictive, dyslipidemic features of metabolic syndrome; how aberrant GPER signalling induces benign prostatic hypertrophy; and how increased intracellular oestradiol stimulates mitogenic change and tumour-cell activators, to cause prostate cancer. In essence, the up-regulation of aromatase produces increased intracellular oestradiol, increases ER-α activation and increases GPER activation, in combination with insulin, to cause aberrant downstream transduction signaling, and thus induce metabolic syndrome and mitogenic prostate growth. To understand this fact, that raised intracellular oestradiol levels in men, induce and promote obesity, gynecomastia, metabolic syndrome, type two diabetes, benign prostatic hypertrophy and prostate cancer, rather than low testosterone, represents a shift in medical thinking, a new awareness, that will reduce the rising incidence of obesity, metabolic syndrome and prostate disease, and significantly improve the health of men worldwide.