Impact of COVID-19 Lockdown on Metabolic/Inflammatory Profile in Adolescents: Cellular Studies and Predictive Biomarkers

CONTEXT

The COVID-19 pandemic and its lockdown restrictions changed people's lifestyles with potential negative impact on health.

OBJECTIVE

This longitudinal study aimed to assess the COVID-19 lockdown influence on the adherence to the Mediterranean diet (MD) pattern and its effects on the metabolic inflammatory profile in a cohort of healthy adolescents.

METHODS

We analyzed anthropometric measurements, body composition, and MD adherence along with serum metabolic and inflammatory profile in 77 healthy adolescents from southern Italy before and after the COVID-19 pandemic lockdown. Additionally, we evaluated the biological properties of prelockdown and postlockdown serum on human HepG2 and HuH-7 hepatic cells.

RESULTS

We did not observe any significant differences in anthropometric and body composition parameters as well as MD adherence score in adolescents between prelockdown and postlockdown COVID-19. Intriguingly, although the metabolic profile of adolescents postlockdown was within the normal range, we evidenced increased levels of fasting glucose, triglycerides, total cholesterol, and low-density lipoprotein (LDL) along with a reduction in high-density lipoprotein (HDL) in postlockdown compared with prelockdown adolescent serum. In addition, elevated levels of tumor necrosis factor (TNF)-α, interleukin-1β, and ferritin were found in postlockdown adolescents compared with their prelockdown counterparts. Consistent with the biochemical parameters, we observed enhanced lipid accumulation with altered mitochondrial functions and increased reactive oxygen species production in HepG2 and HuH-7 cells treated with pooled serum from postlockdown with respect to prelockdown period. Receiver operator characteristic curve analysis identified total cholesterol, LDL, HDL, TNF-α, and ferritin to be predictive serum markers for metabolic and inflammatory profiling after the lockdown period.

CONCLUSION

Our findings highlight that the COVID-19 lockdown, forcing sedentary behavior, had a negative impact on adolescents' metabolic and inflammatory profile which may result in long-term poor health outcomes.

FoxO3a Drives the Metabolic Reprogramming in Tamoxifen-Resistant Breast Cancer Cells Restoring Tamoxifen Sensitivity

Tamoxifen-resistant breast cancer cells (TamR-BCCs) are characterized by an enhanced metabolic phenotype compared to tamoxifen-sensitive cells. FoxO3a is an important modulator of cell metabolism, and its deregulation has been involved in the acquisition of tamoxifen resistance. Therefore, tetracycline-inducible FoxO3a was overexpressed in TamR-BCCs (TamR/TetOn-AAA), which, together with their control cell line (TamR/TetOn-V), were subjected to seahorse metabolic assays and proteomic analysis. FoxO3a was able to counteract the increased oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) observed in TamR by reducing their energetic activity and glycolytic rate. FoxO3a caused glucose accumulation, very likely by reducing LDH activity and mitigated TamR biosynthetic needs by reducing G6PDH activity and hindering NADPH production via the pentose phosphate pathway (PPP). Proteomic analysis revealed a FoxO3a-dependent marked decrease in the expression of LDH as well as of several enzymes involved in carbohydrate metabolism (e.g., Aldolase A, LDHA and phosphofructokinase) and the analysis of cBioPortal datasets of BC patients evidenced a significant inverse correlation of these proteins and FoxO3a. Interestingly, FoxO3a also increased mitochondrial biogenesis despite reducing mitochondrial functionality by triggering ROS production. Based on these findings, FoxO3a inducing/activating drugs could represent promising tools to be exploited in the management of patients who are refractory to antiestrogen therapy.

Association between HMGCR, CRP, and CETP gene polymorphisms and metabolic/inflammatory serum profile in healthy adolescents

BACKGROUND

The complex interplay between health, lifestyle and genetics represents a critical area of research for understanding and promoting human well-being. Importantly, genetics plays a key role in determining individual susceptibility to disease and response to lifestyle. The aim of the present study was to identify genetic factors related to the metabolic/inflammatory profile of adolescents providing new insights into the individual predisposition to the different effects of the substances from the environment.

METHODS

Association analysis of genetic variants and biochemical parameters was performed in a total of 77 healthy adolescents recruited in the context of the DIMENU study.

RESULTS

Polymorphisms of 3-hydroxy-3-methylglutaril coenzyme A reductase (HMGCR; rs142563098), C-reactive protein gene (CRP; rs1417938, rs1130864), cholesteryl ester transfer protein (CETP; rs5030708), interleukin (IL)-10 (IL-10; rs3024509) genes were significantly associated (p < 0.05) with various serum metabolic parameters. Of particular interest were also the correlations between the HMGCRpolymorphism (rs3846663) and tumor necrosis factor (TNF)-α levels, as well Fatty-acid desaturase (FADS) polymorphism (rs7481842) and IL-10 level opening a new link between lipidic metabolism genes and inflammation.

CONCLUSION

In this study, we highlighted associations between single nucleotide polymorphisms (SNPs) and serum levels of metabolic and inflammatory parameters in healthy young individuals, suggesting the importance of genetic profiling in the prevention and management of chronic disease.

Androgens Modulate Bcl-2 Agonist of Cell Death (BAD) Expression and Function in Breast Cancer Cells

Androgen receptor (AR) expression in estrogen receptor-positive (ER+) breast cancer (BC) correlates with lower tumor grade and a better clinical outcome. Additionally, in normal mammary epithelium or ER+ BC preclinical models, androgens counteract basal/ER-dependent proliferation. Here, we report an additional mechanism, underlining the protective role exerted by AR. Specifically, the activation of intracellular AR upregulates the Bcl-2-family protein BAD, and TCGA database analyses show that in ER+ BC, BAD expression is associated with better disease-free survival. Ligand-activated AR influences its own and BAD cellular compartmentalization by enhancing levels in the nucleus, as well as in mitochondrial fractions. In both compartments, BAD exerts unconventional functions. In the nucleus, BAD and AR physically interact and, upon androgen stimulation, are recruited at the AP-1 and ARE sites within the cyclin D1 promoter region, contributing to explaining the anti-proliferative effect of androgens in BC cells. Androgens cause an enrichment in BAD and AR content in the mitochondria, correlated with a decrease in mitochondrial function. Thus, we have defined a novel mechanism by which androgens modulate BAD expression, its mitochondria localization, and nuclear content to force its ability to act as a cell cycle inhibitor, strengthening the protective role of androgen signaling in estrogen-responsive BCs.

The Omega-3 Docosahexaenoyl Ethanolamide Reduces CCL5 Secretion in Triple Negative Breast Cancer Cells Affecting Tumor Progression and Macrophage Recruitment

Triple-negative breast cancer (TNBC), an aggressive breast cancer subtype lacking effective targeted therapies, is considered to feature a unique cellular microenvironment with high infiltration of tumor-associated macrophages (TAM), which contribute to worsening breast cancer patient outcomes. Previous studies have shown the antitumoral actions of the dietary omega-3 docosahexaenoic acid (DHA) in both tumor epithelial and stromal components of the breast cancer microenvironment. Particularly in breast cancer cells, DHA can be converted into its conjugate with ethanolamine, DHEA, leading to a more effective anti-oncogenic activity of the parent compound in estrogen receptor-positive breast cancer cells. Here, we investigated the ability of DHEA to attenuate the malignant phenotype of MDA-MB-231 and MDA-MB-436 TNBC cell lines, which in turn influenced TAM behaviors. Our findings revealed that DHEA reduced the viability of TNBC cells in a concentration-dependent manner and compromised cell migration and invasion. Interestingly, DHEA inhibited oxygen consumption and extracellular acidification rates, reducing respiration and the glycolytic reserve in both cell lines. In a co-culture system, TNBC cells exposed to DHEA suppressed recruitment of human THP-1 cells, reduced their viability, and the expression of genes associated with TAM phenotype. Interestingly, we unraveled that the effects of DHEA in TNCB cells were mediated by reduced C-C motif chemokine ligand 5 (CCL5) expression and secretion affecting macrophage recruitment. Overall, our data, shedding new light on the antitumoral effects of DHA ethanolamine-conjugated, address this compound as a promising option in the treatment of TNBC patients.

LPL, FNDC5 and PPARγ gene polymorphisms related to body composition parameters and lipid metabolic profile in adolescents from Southern Italy

Background

Plasma lipid profile and anthropometric variables are known to be under strong genetic control and the identification of genetic variants associated with bioclinical parameters is of considerable public health importance. In this study, a young cohort of healthy individuals was genotyped for genes related to health and pathological conditions, to analyze the association of single nucleotide polymorphisms (SNPs) with different bioclinical parameters, adherence to the Mediterranean Diet (MD) and physical activity, studying the role of lifestyle and body composition parameters on biochemical metabolic profile.

Methods

Association analysis of single variants in the genes of lipoprotein lipase (LPL), fibronectin type III domain containing protein 5 (FNDC5), and peroxisome proliferator-activated receptor-gamma (PPARγ) and haplotype analyses were performed.

Results

Multiple (n = 14) common variants in the three genes demonstrated a significant effect on plasma lipoprotein-lipid levels and/or on biochemical parameters in our sample. Specifically, SNPs were related to lipid metabolism (rs3866471, rs4922115, rs11570892, rs248, rs316, rs1059507, rs1801282) or glycemic profile (rs3208305) or anthropometric parameters (rs3480, rs726344, rs1570569) for a total of 26 significant associations (P < 0.01 and/or P < 0.05) and two haplotypes, for the first time, were strongly associated with lipid and body composition parameters. Interestingly, we identified twenty-four new variants not previously described in the literature and a novel significant association between rs80143795 and body composition.

Conclusions

In this study we confirm the association between these SNPs on lipid metabolism and body parameters also in a young cohort, indicating the important role of these genetic factors as determinants of health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03314-w.

Impact of Mediterranean Diet Food Choices and Physical Activity on Serum Metabolic Profile in Healthy Adolescents: Findings from the DIMENU Project

Adolescent nutrition and healthy dietary patterns, particularly the Mediterranean diet (MD), have been associated with improved health status and decreased risk of various chronic and metabolic diseases later in life. The aim of this study was to evaluate the impact of the Mediterranean food choices on lipid and glycemic metabolic profile in the total population and in adolescents grouped according to their physical activity (PA) levels at the time of recruitment (T0) and after six months from the administration of a personalized Mediterranean meal plan (T1). As part of the DIMENU study, 85 adolescents underwent measurements of lipid and glucose metabolic profile at T0 and T1. Using three positive items from KIDMED test related to the consumption of typical Mediterranean food (olive oil, fish, and nuts) and three negative items on dietary habits (going to fast-food, consuming biscuits, and candies), we categorized adolescents into six sets in which biochemical parameters were analyzed. In the total sample, significant reductions in serum total cholesterol, LDL, and glucose concentrations were observed for all the sets over the study period. Notably, active subjects, who had a better serum metabolic profile, showed significant improvements of glycemic control after 6 month follow up, while in sedentary adolescents and in those performing moderate PA significant reduction in glycemia, total cholesterol, and LDL was found in all sets. In conclusion, adopting the typical Mediterranean food choices led to a significant reduction in glucose and lipid profile in healthy adolescents, thus making the MD and PA a winning combination for health status.

FoxO3a Inhibits Tamoxifen-Resistant Breast Cancer Progression by Inducing Integrin α5 Expression

Resistance to endocrine therapy is still a major clinical challenge in the management of estrogen receptor α-positive (ERα+) breast cancer (BC). Here, the role of the Forkhead box class O (FoxO)3a transcription factor in tumor progression has been evaluated in tamoxifen-resistant BC cells (TamR), expressing lower levels of FoxO3a compared to sensitive ones. FoxO3a re-expression reduces TamR motility (wound-healing and transmigration assays) and invasiveness (matrigel transwell invasion assays) through the mRNA (qRT-PCR) and protein (Western blot) induction of the integrin α5 subunit of the α5β1 fibronectin receptor, a well-known membrane heterodimer controlling cell adhesion and signaling. The induction occurs through FoxO3a binding to a specific Forkhead responsive core sequence located on the integrin α5 promoter (cloning, luciferase, and ChIP assays). Moreover, FoxO3a failed to inhibit migration and invasion in integrin α5 silenced (siRNA) cells, demonstrating integrin α5 involvement in both processes. Finally, using large-scale gene expression data sets, a strong positive correlation between FoxO3a and integrin α5 in ERα+, but not in ER-negative (ERα-), BC patients emerged. Altogether, our data show how the oncosuppressor FoxO3a, by increasing the expression of its novel transcriptional target integrin α5, reverts the phenotype of endocrine-resistant BC toward a lower aggressiveness.

Nutrition Education Program and Physical Activity Improve the Adherence to the Mediterranean Diet: Impact on Inflammatory Biomarker Levels in Healthy Adolescents From the DIMENU Longitudinal Study

Adherence to Mediterranean diet (MD) and physical activity (PA) in adolescence represent powerful indicators of healthy lifestyles in adulthood. The aim of this longitudinal study was to investigate the impact of nutrition education program (NEP) on the adherence to the MD and on the inflammatory status in healthy adolescents, categorized into three groups according to their level of PA (inactivity, moderate intensity, and vigorous intensity). As a part of the DIMENU (Dieta Mediterranea & Nuoto) study, 85 adolescents (aged 14–17 years) participated in the nutrition education sessions provided by a team of nutritionists and endocrinologists at T0. All participants underwent anthropometric measurements, bio-impedentiometric analysis (BIA), and measurements of inflammatory biomarkers such as ferritin, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels. Data were collected at baseline (T0) and 6 months after NEP (T1). To assess the adherence to the MD, we used KIDMED score. In our adolescents, we found an average MD adherence, which was increased at T1 compared with T0 (T0: 6.03 ± 2.33 vs. T1: 6.96 ± 2.03, p = 0.002), with an enhanced percentage of adolescents with optimal (≥8 score) MD adherence over the study period (T0: 24.71% vs. T1: 43.52%, p = 0.001). Interestingly, in linear mixed-effects models, we found that NEP and vigorous-intensity PA levels independently influenced KIDMED score (β = 0.868, p < 0.0001 and β = 1.567, p = 0.009, respectively). Using ANOVA, NEP had significant effects on serum ferritin levels (p < 0.001), while either NEP or PA influenced ESR (p = 0.035 and 0.002, respectively). We also observed in linear mixed-effects models that NEP had a negative effect on ferritin and CRP (β = −14.763, p < 0.001 and β = −0.714, p = 0.02, respectively). Our results suggest the usefulness to promote healthy lifestyle, including either nutrition education interventions, or PA to improve MD adherence and to impact the inflammatory status in adolescence as a strategy for the prevention of chronic non-communicable diseases over the entire lifespan.

Self-Perceived Physical Activity and Adherence to the Mediterranean Diet in Healthy Adolescents during COVID-19: Findings from the DIMENU Pilot Study

The global pandemic coronavirus disease (COVID-19) resulted in restrictions which forced adolescents to stay at home and influenced their food habits and lifestyles with potential negative health impact. This study aims to investigate the self-reported physical activity (PA) and eating habits related to the consumption of Mediterranean foods in a sample of adolescents during the COVID-19 lockdown enrolled into the DIMENU study. A web survey was launched for 91 adolescents (aged 15-17 years) to assess their adherence to the Mediterranean Diet using the KIDMED test and lifestyle habits using a questionnaire designed following recommendations by Italian National Institute of Health (ISS score). Our results indicate that most of the sample declared no changes in eating habits and PA without sex differences. After dividing the sample into active and sedentary groups based on the self-perceived PA, we found that KIDMED and ISS scores were significantly higher (p = 0.0028 and p = 0.0001, respectively) in active adolescents. Moreover, KIDMED was positively correlated with ISS only in active adolescents (r = 0.311, p = 0.0185). In conclusion, our data underline the impact of the PA on the Mediterranean diet adherence in adolescents during the lockdown, suggesting the usefulness of promoting wellness programs directed towards inactive individuals to increase their awareness on the importance of healthy lifestyles.

Leptin Signaling Contributes to Aromatase Inhibitor Resistant Breast Cancer Cell Growth and Activation of Macrophages

Obesity represents a risk factor for breast cancer development and therapy resistance, but the molecular players underling these links are unclear. Here, we identify a role for the obesity-cytokine leptin in sustaining aromatase inhibitor (AI) resistant growth and progression in breast cancer. Using as experimental models MCF-7 breast cancer cells surviving long-term treatment with the AI anastrozole (AnaR) and Ana-sensitive counterparts, we found that AnaR cells expressed higher levels of leptin and its receptors (ObR) along with a constitutive activation of downstream effectors. Accordingly, leptin signaling inhibition reduced only AnaR cell growth and motility, highlighting the existence of an autocrine loop in mechanisms governing drug-resistant phenotypes. In agreement with ObR overexpression, increasing doses of leptin were able to stimulate to a greater extent growth and migration in AnaR than sensitive cells. Moreover, leptin contributed to enhanced crosstalk between AnaR cells and macrophages within the tumor microenvironment. Indeed, AnaR, through leptin secretion, modulated macrophage profiles and increased macrophage motility through CXCR4 signaling, as evidenced by RNA-sequencing, real-time PCR, and immunoblotting. Reciprocally, activated macrophages increased AnaR cell growth and motility in coculture systems. In conclusion, acquired AI resistance is accompanied by the development of a leptin-driven phenotype, highlighting the potential clinical benefit of targeting this cytokine network in hormone-resistant breast cancers, especially in obese women.

Impact of Vigorous-Intensity Physical Activity on Body Composition Parameters, Lipid Profile Markers, and Irisin Levels in Adolescents: A Cross-Sectional Study

In adolescence, health status is influenced by several factors, including dietary pattern and physical activity (PA) which are crucial elements of lifestyle in terms of prevention and treatment of metabolic and chronic diseases. The current study aimed to explore the impact of the different intensity levels of PA along with the adherence to a Mediterranean diet (MD), on body composition indices and metabolic parameters in a cohort of adolescents, thereby investigating potential predictors of health behavior in youth. This cross-sectional study was carried out among 92 participants (44 girls and 48 boys, aged 14 to 17 years), which were divided into the following three groups according to intensity levels of PA: Group A (physical inactivity), Group B (moderate PA), and Group C (vigorous-intensity PA). The Questionnaire of Adherence to the Mediterranean Diet (KIDMED test) was used to assess both diet composition and adherence to a MD. All subjects underwent anthropometric measurements, bio-impedentiometric analysis for body composition parameters, and biochemical and hormonal measurements. The majority of adolescents (60.87%) had a medium adherence to the MD, and even a better distribution of food rates was found in adolescents performing vigorous-intensity PA. A comparison of anthropometric measurements and body composition parameters among groups showed that body mass index and fat mass (FM) were significantly lower while body cell mass (BCM), free fat mass (FFM), phase angle (PhA), and total body water (TBW) were higher in Group C adolescents as compared with those of Group A. In Group C, insulin resistance (HOMA-IR) was reduced and insulin levels were inversely associated with FFM (r = −0.454 and p = 0.004) and directly correlated with FM (r = 0.331 and p = 0.003). In the same Group C, we observed elevated serum irisin levels and lower lipid profile markers as compared with Group A. Interestingly, irisin negatively correlated with both total cholesterol (r = −0.428 and p = 0.04) and LDL (r = −0.468 and p = 0.02) in Group C. Finally, a receiver operator characteristic curve (ROC) analysis revealed irisin, LDL, HDL, and body composition variables (FFM, BMC, PhA, and TBW) as the most predictive measures for vigorous-intensity PA. Our results highlight the importance of developing healthy lifestyle programs that include improving the intensity of PA among a young population as a superior strategy for ensuring a better quality of life.

Modulating Tumor-Associated Macrophage Polarization by Synthetic and Natural PPARγ Ligands as a Potential Target in Breast Cancer

Activation of peroxisome proliferator-activated receptor gamma (PPARγ) elicits anti-proliferative effects on different tumor cells, including those derived from breast cancer. PPARγ is also expressed in several cells of the breast tumor microenvironment, among which tumor associated macrophages (TAMs) play a pivotal role in tumor progression and metastasis. We explored the ability of synthetic and natural PPARγ ligands to modulate TAM polarization. The ligands included rosiglitazone (BRL-49653), and two docosahexaenoic acid (DHA) conjugates, N-docosahexaenoyl ethanolamine (DHEA) and N-docosahexaenoyl serotonin (DHA-5-HT). Human THP-1 monocytic cells were differentiated into M0, M1 and M2 macrophages that were characterized by qRT-PCR, ELISA and western blotting. A TAM-like phenotypic state was generated by adding two different breast cancer cell conditioned media (BCC-CM) to the cultures. Macrophages exposed to BCC-CM concomitantly exhibited M1 and M2 phenotypes. Interestingly, rosiglitazone, DHEA and DHA-5-HT attenuated cytokine secretion by TAMs, and this effect was reversed by the PPARγ antagonist GW9662. Given the key role played by PPARγ in the crosstalk between cancer cells and TAMs in tumor progression, its activation via endogenous or synthetic ligands may lead to novel strategies that target both epithelial neoplastic cells and the tumor microenvironment.

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.

Adherence to the Mediterranean diet pattern among university staff: a cross-sectional web-based epidemiological study in Southern Italy

In this cross-sectional web-survey, carried out in 340 employees (24-67 years) among university staff of Southern Italy, we assessed the adherence to the Mediterranean Diet (MD). Using an online questionnaire based on validated 14-point MD Adherence Screener (MEDAS), the mean of the score was 7.34 (±1.9) for total population independently of sex. In population divided by the cut-off age of 45 years, MD adherence resulted significantly lower in younger respect to older group (p = .003). In multiple regression analyses we observed the direct association between MEDAS score and older age group also after adjustments. Importantly, in all sample the percentage of adherers to recommendations for fruits, nuts and fish resulted outside dietary guidelines. The present findings underscore the need to develop healthy education programmes aimed to improve the consumption of several components of the MD, particularly among young adults, in order to prevent the early onset of chronic non-transmittable diseases.

AIB1 sequestration by androgen receptor inhibits estrogen-dependent cyclin D1 expression in breast cancer cells

Background

Androgens, through their own receptor, play a protective role on breast tumor development and progression and counterbalance estrogen-dependent growth stimuli which are intimately linked to breast carcinogenesis.

Methods

Cell counting by trypan blu exclusion was used to study androgen effect on estrogen-dependent breast tumor growth. Quantitative Real Time RT–PCR, western blotting, transient transfection, protein immunoprecipitation and chromatin immunoprecipitation assays were carried out to investigate how androgen treatment and/or androgen receptor overexpression influences the functional interaction between the steroid receptor coactivator AIB1 and the estrogen- or androgen receptor which, in turn affects the estrogen-induced cyclin D1 gene expression in MCF-7 breast cancer cells. Data were analyzed by ANOVA.

Results

Here we demonstrated, in estrogen receptor α (ERα)-positive breast cancer cells, an androgen-dependent mechanism through which ligand-activated androgen receptor (AR) decreases estradiol-induced cyclin D1 protein, mRNA and gene promoter activity. These effects involve the competition between AR and ERα for the interaction with the steroid receptor coactivator AIB1, a limiting factor in the functional coupling of the ERα with the cyclin D1 promoter. Indeed, AIB1 overexpression is able to reverse the down-regulatory effects exerted by AR on ERα-mediated induction of cyclin D1 promoter activity. Co-immunoprecipitation studies indicated that the preferential interaction of AIB1 with ERα or AR depends on the intracellular expression levels of the two steroid receptors. In addition, ChIP analysis evidenced that androgen administration decreased E₂-induced recruitment of AIB1 on the AP-1 site containing region of the cyclin D1 gene promoter.

Conclusions

Taken together all these data support the hypothesis that AIB1 sequestration by AR may be an effective mechanism to explain the reduction of estrogen-induced cyclin D1 gene activity. In estrogen-dependent breast cancer cell proliferation, these findings reinforce the possibility that targeting AR signalling may potentiate the effectiveness of anti-estrogen adjuvant therapies.

Progesterone Receptor B signaling Reduces Breast Cancer Cell Aggressiveness: Role of Cyclin-D1/Cdk4 Mediating Paxillin Phosphorylation

Progesterone-Receptor (PR) positivity is related with an enhanced response to breast cancer therapy, conversely cyclin D1 (CD1) is a retained marker of poor outcome. Herein, we demonstrate that hydroxyprogesterone (OHPg) through progesterone receptor B (PR-B) reduces breast cancer cell aggressiveness, by targeting the cytoplasmic CD1. Specifically, OHPg diminishes CD1 expression by a transcriptional regulation due to the recruitment of PR-B at a canonical half-PRE site of the CD1 promoter, together with HDAC1, determining a chromatin conformation less prone for gene transcription. CD1, together with its kinase partner Cdk4, regulates cell migration and metastasis, through the association with key components of focal adhesion, such as Paxillin (Pxn). Kaplan-Meier analysis shows that low Pxn expression was associated with increased distant metastasis-free survival in luminal A PR+ breast carcinomas. Interestingly, OHPg treatment reduced Pxn content in T47-D and MCF-7 cells; besides, the interaction between endogenous cytoplasmic CD1/Cdk4 with Pxn was reduced. This was consistent with the reduction of p-Ser83Pxn levels, crucially causing the delay in cell migration and a concomitant inhibition of Rac1 activity and p-PAK. Collectively, these findings support the role of PR-B in breast epithelial cell integrity and reinforce the importance in targeting PR-B as a potential strategy to restrict breast tumor cell invasion and metastasis.

Dealing with Skin and Blood-Brain Barriers: The Unconventional Challenges of Mesoporous Silica Nanoparticles

Advances in nanotechnology for drug delivery are fostering significant progress in medicine and diagnostics. The multidisciplinary nature of the nanotechnology field encouraged the development of innovative strategies and materials to treat a wide range of diseases in a highly specific way, which allows reducing the drug dosage and, consequently, improving the patient's compliance. Due to their good biocompatibility, easy synthesis, and high versatility, inorganic frameworks represent a valid tool to achieve this aim. In this context, Mesoporous Silica Nanoparticles (MSNs) are emerging in the biomedical field. For their ordered porosity and high functionalizable surface, achievable with an inexpensive synthesis process and being non-hazardous to biological tissues, MSNs offer ideal solutions to host, protect, and transport drugs to specific target sites. Extensive literature exists on the use of MSNs as targeted vehicles for systemic (chemo) therapy and for imaging/diagnostic purposes. However, the aim of this review is to give an overview of the last updates on the potential applications of the MSNs for Topical Drug Delivery (TDD) and as drug delivery systems into the brain, discussing their performances and advantages in dealing with these intriguing biological barriers.

FoxO3a Mediates the Inhibitory Effects of the Antiepileptic Drug Lamotrigine on Breast Cancer Growth

Breast cancer is a complex and heterogeneous disease, with distinct histologic features dictating the therapy. Although the clinical outcome of breast cancer patients has been considerably improved, the occurrence of resistance to common endocrine and chemotherapy treatments remains the major cause of relapse and mortality. Thus, efforts in identifying new molecules to be employed in breast cancer therapy are needed. As a "faster" alternative to reach this aim, we evaluated whether lamotrigine, a broadly used anticonvulsant, could be "repurposed" as an antitumoral drug in breast cancer. Our data show that lamotrigine inhibits the proliferation, the anchorage-dependent, and independent cell growth in breast cancer cells (BCC), including hormone-resistant cell models. These effects were associated with cell-cycle arrest and modulation of related proteins (cyclin D1, cyclin E, p27^Kip1, and p21^Waf1/Cip1), all target genes of FoxO3a, an ubiquitous transcription factor negatively regulated by AKT. Lamotrigine also increases the expression of another FoxO3a target, PTEN, which, in turn, downregulates the PI3K/Akt signaling pathway, with consequent dephosphorylation, thus activation, of FoxO3a. Moreover, lamotrigine induces FoxO3a expression by increasing its transcription through FoxO3a recruitment on specific FHRE located on its own promoter, in an autoregulatory fashion. Finally, lamotrigine significantly reduced tumor growth in vivo, increasing FoxO3a expression.Implications: The anticonvulsant drug lamotrigine shows strong antiproliferative activity on breast cancer, both in vitro and in vivo Thus, drug repurposing could represent a valuable option for a molecularly targeted therapy in breast cancer patients. Mol Cancer Res; 16(6); 923-34. ©2018 AACR.

Ligand activated progesterone receptor B drives autophagy-senescence transition through a Beclin-1/Bcl-2 dependent mechanism in human breast cancer cells

Loss of progesterone-receptors (PR) expression is associated with breast cancer progression. Herein we provide evidence that OHPg/PR-B through Beclin-1 evoke autophagy-senescence transition, in breast cancer cells. Specifically, OHPg increases Beclin-1 expression through a transcriptional mechanism due to the occupancy of Beclin-1 promoter by PR-B, together with the transcriptional coactivator SRC-2. This complex binds at a canonical half progesterone responsive element, which is fundamental for OHPg effects, as shown by site-directed mutagenesis. Beside, OHPg via non-genomic action rapidly activates JNK, which phosphorylates Bcl-2, producing the functional release from Beclin-1 interaction. This is not linked to an efficient autophagic flux, since p62 levels, marker of degradation via lysosomes, were not reduced after sustained OHPg stimulus. Instead, the cell cycle inhibitor p27 was induced, together with an irreversible G1 arrest, hallmark of cellular senescence. Specifically the increase of senescence-associated β-galactosidase activity was blocked by Bcl-2 siRNA but also by Beclin-1 siRNA. Collectively these findings support the importance of PR-B expression in breast cancer cells, thus targeting PR-B may be a useful strategy to provide additional approaches to existing therapies for breast cancer patients.

Androgens downregulate miR-21 expression in breast cancer cells underlining the protective role of androgen receptor

Although the protective role of androgen receptor (AR) in breast cancer (BC) is well established, the mechanisms involved remains largely unexplored. MicroRNAs play fundamental roles in many biological processes, including tumor cell development and metastasis. Herein, we report that androgens reduce BC cells proliferation acting as a negative modulator of the onco-miRNA-21.

The synthetic androgen miboleron (Mib) decreases BC cell proliferation induced by miR-21 over-expression and AR knockdown evidenced the requirement of AR in the down-regulation of miR-21 expression. These effects seem to be a general mechanism occurring in BC tissues.

Chromatin immune-precipitation (ChIP) analysis disclosed the binding of AR to a specific ARE sequence in miR-21 proximal promoter and recognizes the recruitment of HDAC3 as component for AR-mediated transcriptional repression. Such event is associated to a significantly reduced PolII binding in Mib treated extracts confirming that activated AR is a transcriptional repressor of miR-21 expression, providing further insight into the protective role of androgens in breast cancer cells.

Collectively, our data and the widespread AR expression in primary and metastatic breast tumours, suggest a careful examination of the therapeutic potential of androgens also in potentiating the effectiveness of anti-oestrogen adjuvant therapies.

Mitochondrial "power" drives tamoxifen resistance: NQO1 and GCLC are new therapeutic targets in breast cancer

Here, we identified two new molecular targets, which are functionally sufficient to metabolically confer the tamoxifen-resistance phenotype in human breast cancer cells. Briefly, ~20 proteins were first selected as potential candidates, based on unbiased proteomics analysis, using tamoxifen-resistant cell lines. Then, the cDNAs of the most promising candidates were systematically transduced into MCF-7 cells. Remarkably, NQO1 and GCLC were both functionally sufficient to autonomously confer a tamoxifen-resistant metabolic phenotype, characterized by i) increased mitochondrial biogenesis, ii) increased ATP production and iii) reduced glutathione levels. Thus, we speculate that pharmacological inhibition of NQO1 and GCLC may be new therapeutic strategies for overcoming tamoxifen-resistance in breast cancer patients. In direct support of this notion, we demonstrate that treatment with a known NQO1 inhibitor (dicoumarol) is indeed sufficient to revert the tamoxifen-resistance phenotype. As such, these findings could have important translational significance for the prevention of tumor recurrence in ER(+) breast cancers, which is due to an endocrine resistance phenotype. Importantly, we also show here that NQO1 has significant prognostic value as a biomarker for the prediction of tumor recurrence. More specifically, higher levels of NQO1 mRNA strongly predict patient relapse in high-risk ER(+) breast cancer patients receiving endocrine therapy (mostly tamoxifen; H.R. > 2.15; p = 0.007).

Mesoporous Silica Nanoparticles in Cancer Therapy: Relevance of the Targeting Function

In the last years, the oncologic research is focusing on the optimization of the clinical approach to the tumor disease, through the development of new therapeutic strategies combining currently used antineoplastic drugs to targeted delivery systems. In fact, due to the drugs poor selectivity for cancer cells, an highly aggressive style of dosing is necessary to eradicate tumors, causing severe toxicity to normal cells. Therefore, localized drug delivery would, ideally, improve the therapeutic efficacy, minimizing side effects. Mesoporous silica nanoparticles (MSNs) have been proposed as a promising class of versatile drug/DNA delivery vehicles, as well as efficient tools for fluorescent cell tracking. To date, the major limitation is that MSNs enter the cells regardless of a target-specific functionalization. Therefore, this review is aimed to give a brief up to date overview on mesoporous silica based-drug delivery vehicles, specifically applied to tumor therapy, giving particular emphasis to the importance of a targeting function grafted on the carrier surface, so to avoid an indiscriminate uptake by cells.

Erratum to: Estrogen receptor beta binds Sp1 and recruits a corepressor complex to the estrogen receptor alpha gene promoter

Erratum to: Breast Cancer Res Treat (2012), 134:569–581, DOI 10.1007/s10549-012-2090-9. Uunfortunately, authors could not find the original film from which the figure was drawn. Therefore, as suggested by the Editor, they have repeated the relative experiment, and ask to publish this new figure as a correction. The authors apologize for any inconvenience that it may cause.

Bergapten induces metabolic reprogramming in breast cancer cells

Alterations in cellular metabolism are among the most consistent hallmarks of cancer. Herein, after a comprehensive metabolic phenotype characterization of MCF7 and ZR75 breast cancer cells, we investigated the activity of bergapten (Bg), a plant-derived compound, against breast cancer. The study of different biochemical pathways involved in cell metabolism revealed that the two cell lines have different bioenergetic phenotypes: MCF7 cells express a glycolytic phenotype only partially oxidative, while ZR75 cells mainly have an oxidative phenotype. In both cell lines, Bg blocked glycolysis and significantly decreased glucose-6-phosphate dehydrogenase (G6PDH) activity promoting glucose accumulation; modulated bioenergetic requirements altering the expression of oxidative phosphorylation (OXPHOS) complexes and ATP production; and induced a lipid-lowering effect since an increased lipase activity concomitantly to a reduction in triglyceride levels was observed. Quantitative data of different metabolites and enzymatic activities were presented. Treatment with Bg resulted in an alteration in different metabolic pathways inducing death in the cells. We report a novel action of the natural product Bg on breast cancer, since it induced metabolic reprogramming by disrupting the interconnected network of different metabolic mechanisms. Bg can be used in combination with other forms of targeted chemotherapy to improve cancer treatment outcomes.

Androgens inhibit aromatase expression through DAX-1: insights into the molecular link between hormone balance and Leydig cancer development

Leydig cell tumors (LCTs) of the testis are steroid-secreting tumors associated with various steroid biosynthetic abnormalities and endocrine dysfunctions. Despite their overall rarity, LCTs are still of substantial interest owing to the paucity of information regarding their exact nature and malignant potential. In the present study, we disclose the ability of androgens to inhibit Leydig tumor cell proliferation by opposing to self-sufficient in situ estrogen production. In rat Leydig tumor cells, R2C, androgen treatment significantly decreases the expression and the enzymatic activity of cytocrome P450 aromatase, responsible for the local conversion of androgens into estrogens. This inhibitory effect relies on androgen receptor (AR) activation and involves negative regulation of the CYP19 gene transcriptional activity through the nuclear orphan receptor DAX-1 (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1). Ligand-activated AR up-regulates the expression of DAX-1 and promotes its increased recruitment within the steroidogenic factor-1 site-containing region of the aromatase proximal promoter II in association with the nuclear receptor corepressor. The biological relevance in LCTs of the newly highlighted functional interplay between AR, DAX-1, and aromatase is underlined by our in vivo observations, revealing a marked down-regulation of AR and DAX-1 expression and a strong increase in aromatase levels in testes tissues from old Fischer rats with spontaneously developed Leydig cell neoplasia, compared with normal testes tissues from younger animals. In elucidating a mechanism by which androgens modulate the growth of Leydig tumor cells, our finding support the hypothesis that maintaining the adequate balance between androgen and estrogens may represent the key for blocking estrogen-secreting Leydigioma development, opening new prospects for therapeutic intervention.

Controlled release of sunitinib in targeted cancer therapy: smart magnetically responsive hydrogels as restricted access materials

A magnetic hydrogel prepared by precipitation polymerization, with restricted access material (RAM) characteristics through the introduction of glycidyl methacrylate, for sunitinib malate release.

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.

Magnetic molecularly imprinted polymers (MMIPs) for carbazole derivative release in targeted cancer therapy

Magnetic Molecularly Imprinted Polymers (MMIPs) are synthesized with the aim to prepare novel devices for 9H-carbazole derivative sustained delivery in targeted cancer therapy.

Evidences that estrogen receptor α interferes with adiponectin effects on breast cancer cell growth

Adiponectin, the most abundant protein secreted by adipose tissue, exhibits insulin-sensitizing, anti-inflammatory, antiatherogenic, and antiproliferative properties. In addition, it appears to play an important role also in the development and progression of several obesity-related malignancies, including breast cancer.   Here, we demonstrated that adiponectin induces a dichotomic effect on breast cancer growth. Indeed, it stimulates growth in ERα+ MCF-7 cells while inhibiting proliferation of ERα- MDA-MB-231 cells. Notably, only in MCF-7 cells adiponectin exposure exerts a rapid activation of MAPK phosphorylation, which is markedly reduced when knockdown of the ERα gene occurred. In addition, adiponectin induces rapid IGF-IR phosphorylation in MCF-7 cells, and the use of ERα siRNA prevents this effect. Moreover, MAPK activation induced by adiponectin was reversed by IGF-IR siRNA. Coimmunoprecipitation studies show the existence of a multiprotein complex involving AdipoR1, APPL1, ERα, IGF-IR, and c-Src that is responsible for MAPK signaling activation in ERα+ positive breast cancer cells. It is well known that in addition to the rapid effects through non-genomic mechanisms, ERα also mediates nuclear genomic actions. In this concern, we demonstrated that adiponectin is able to transactivate ERα in MCF-7 cells. We showed the classical features of ERα transactivation: nuclear localization, downregulation of mRNA and protein levels, and upregulation of estrogen-dependent genes. Thus, our study clarifies the molecular mechanism through which adiponectin modulates breast cancer cell growth, providing evidences on the cell-type dependency of adiponectin action in relationship to ERα status.

The estrogen receptor α is the key regulator of the bifunctional role of FoxO3a transcription factor in breast cancer motility and invasiveness

The role of the Forkhead box class O (FoxO)3a transcription factor in breast cancer migration and invasion is controversial. Here we show that FoxO3a overexpression decreases motility, invasiveness, and anchorage-independent growth in estrogen receptor α-positive (ERα+) cancer cells while eliciting opposite effects in ERα-silenced cells and in ERα-negative (ERα-) cell lines, demonstrating that the nuclear receptor represents a crucial switch in FoxO3a control of breast cancer cell aggressiveness. In ERα+ cells, FoxO3a-mediated events were paralleled by a significant induction of Caveolin-1 (Cav1), an essential constituent of caveolae negatively associated to tumor invasion and metastasis. Cav1 induction occurs at the transcriptional level through FoxO3a binding to a Forkhead responsive core sequence located at position -305/-299 of the Cav1 promoter. 17β-estradiol (E2) strongly emphasized FoxO3a effects on cell migration and invasion, while ERα and Cav1 silencing were able to reverse them, demonstrating that both proteins are pivotal mediators of these FoxO3a controlled processes. In vivo, an immunohistochemical analysis on tissue sections from patients with ERα+ or ERα- invasive breast cancers or in situ ductal carcinoma showed that nuclear FoxO3a inversely (ERα+) or directly (ERα-) correlated with the invasive phenotype of breast tumors. In conclusion, FoxO3a role in breast cancer motility and invasion depends on ERα status, disclosing a novel aspect of the well-established FoxO3a/ERα interplay. Therefore FoxO3a might become a pursuable target to be suitably exploited in combination therapies either in ERα+ or ERα- breast tumors.

Leptin increases HER2 protein levels through a STAT3-mediated up-regulation of Hsp90 in breast cancer cells

Obesity condition confers risks to breast cancer development and progression, and several reports indicate that the adipokine leptin, whose synthesis and plasma levels increase with obesity, might play an important role in modulating breast cancer cell phenotype. Functional crosstalk occurring between leptin and different signaling molecules contribute to breast carcinogenesis. In this study, we show, in different human breast cancer cell lines, that leptin enhanced the expression of a chaperone protein Hsp90 resulting in increased HER2 protein levels. Silencing of Hsp90 gene expression by RNA interference abrogated leptin-mediated HER2 up-regulation. Leptin effects were dependent on JAK2/STAT3 activation, since inhibition of this signaling cascade by AG490 or ectopic expression of a STAT3 dominant negative abrogated leptin-induced HER2 and Hsp90 expressions. Functional experiments showed that leptin treatment significantly up-regulated human Hsp90 promoter activity. This occurred through an enhanced STAT3 transcription factor binding to its specific responsive element located in the Hsp90 promoter region as revealed by electrophoretic mobility shift assay and chromatin immunoprecipitation assay. Analysis of HER2, Akt and MAPK phosphorylation levels revealed that leptin treatment amplified the responsiveness of breast cancer cells to growth factor stimulation. Furthermore, we found that long-term leptin exposure reduced sensitivity of breast cancer cells to the antiestrogen tamoxifen. In the same experimental conditions, the combined treatment of tamoxifen with the Hsp90 inhibitor 17-AAG completely abrogated leptin-induced anchorage-independent breast cancer cell growth. In conclusion, our results highlight, for the first time, the ability of the adipocyte-secreted factor leptin to modulate Hsp90/HER2 expressions in breast cancer cells providing novel insights into the molecular mechanism linking obesity to breast cancer growth and progression.

Sperm metabolism in pigs: a role for peroxisome proliferator-activated receptor gamma (PPARγ)

Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear hormone receptor expressed predominantly in adipose tissue, also implicated in energy homeostasis. In this study, we used western blotting and immunofluorescence techniques to demonstrate for the first time that pig spermatozoa express PPARγ. To investigate the functional role of PPARγ in pig sperm, we evaluated its action on different events that characterize the biology of sperm cells, i.e. motility, capacitation, viability and acrosome reaction, using the PPARγ-agonist 15-deoxy-12,14-prostaglandin J2 (PGJ2). In responses to PGJ2 treatment, motility, cholesterol efflux and tyrosine phosphorylation were increased, which broadens the role of PPARγ from that previously described in the literature, as it also acts to improve sperm functionality. To further our understanding of the significance of PPARγ in pig sperm, we focused its effects on lipid and glucose metabolism. Evaluation of triglyceride content and lipase, acyl-CoA dehydrogenase and G6PDH activities suggests that PPARγ induces energy expenditure in pig spermatozoa. These data represent a meaningful advance in the field of sperm energy metabolism. Taken together, our results demonstrate for the first time that PPARγ is expressed by pig sperm, thus improving its functionalities in terms of motility, capacitation, acrosome reaction, survival and metabolism.

G protein-coupled estrogen receptor mediates the up-regulation of fatty acid synthase induced by 17β-estradiol in cancer cells and cancer-associated fibroblasts

Activation of lipid metabolism is an early event in carcinogenesis and a central hallmark of many tumors. Fatty acid synthase (FASN) is a key lipogenic enzyme catalyzing the terminal steps in the de novo biogenesis of fatty acids. In cancer cells, FASN may act as a metabolic oncogene, given that it confers growth and survival advantages to these cells, whereas its inhibition effectively and selectively kills tumor cells. Hormones such as estrogens and growth factors contribute to the transcriptional regulation of FASN expression also through the activation of downstream signaling and a cross-talk among diverse transduction pathways. In this study, we demonstrate for the first time that 17β-estradiol (E2) and the selective GPER ligand G-1 regulate FASN expression and activity through the GPER-mediated signaling, which involved the EGF receptor/ERK/c-Fos/AP1 transduction pathway, as ascertained by using specific pharmacological inhibitors, performing gene-silencing experiments and ChIP assays in breast SkBr3, colorectal LoVo, hepatocarcinoma HepG2 cancer cells, and breast cancer-associated fibroblasts. In addition, the proliferative effects induced by E2 and G-1 in these cells involved FASN as the inhibitor of its activity, named cerulenin, abolished the growth response to both ligands. Our data suggest that GPER may be included among the transduction mediators involved by estrogens in regulating FASN expression and activity in cancer cells and cancer-associated fibroblasts that strongly contribute to cancer progression.

Inhibition of Leydig tumor growth by farnesoid X receptor activation: the in vitro and in vivo basis for a novel therapeutic strategy

Leydig cell tumors (LCTs) are the most common tumors of the gonadal stroma and represent about 3% of all testicular neoplasms. In most cases, LCTs are benign; however, if the tumor is malignant, no effective treatments are currently available. We have recently reported that farnesoid X receptor (FXR) is expressed in R2C Leydig tumor cells, and it reduces the estrogen-dependent cell proliferation by negatively regulating aromatase expression. Here, we demonstrated that treatment with GW4064, a specific FXR agonist, markedly reduced Leydig tumor growth in vivo by inhibiting proliferation and inducing apoptosis. Indeed, the tumors from GW4064-treated mice exhibited a decrease in the expression of the proliferation marker Ki-67 and aromatase along with an increase in the apoptotic nuclei. FXR activation induced an enhanced poly(ADP-ribose) polymerase cleavage, a marked DNA fragmentation and a strong increase in TUNEL-positive R2C cells also in vitro. Moreover, in both in vivo and in vitro models, FXR ligands upregulated mRNA and protein levels of p53 and of its downstream effector p21(WAF1/Cip1) . Functional experiments showed that FXR ligands upregulated p53 promoter activity and this occurred through an increased binding of FXR/nuclear factor-kB (NF-kB) complex to the NF-kB site located within p53 promoter region as revealed by electrophoretic mobility shift assay and chromatin immunoprecipitation analysis. Taken together, results from our study show, for the first time, that treatment with FXR ligands induces Leydig tumor regression in vivo, suggesting that activation of FXR may represent a promising therapeutic strategy for LCTs.

Progesterone through progesterone receptors affects survival and metabolism of pig sperm

Progesterone receptors (PR) through interaction with the specific ligand progesterone (PRG), play a central coordinate role in different reproductive events. In this study conventional PR were identified in boar spermatozoa by Western blotting. Immunofluorescence techniques indicate that PR are located at sperm acrosomal region, suggesting a possible role in the oocyte fertilization events. Treatment with 17-hydroxyprogesterone (17-OHP) enhanced viability and induced cholesterol efflux, serine and tyrosine phosphorylation, p-Bcl2, p-Akt that are known hallmarks of capacitation in sperm. The analysis of the triglyceride contents, lipase and acyl-CoA dehydrogenase activities, as well as the G6PDH activity, was conducted so as to address whether there was an increase in energy expenditure via 17-OHP through the PR. Taken together these results, particularly the 17-OHP action on boar sperm lipid and glucose metabolism, give emphasis to the role of PR in sperm physiology within the oviductal environment. Moreover the present study highlights, the effect of PRG via PR on boar sperm survival, renewing the role of this hormone in male reproduction as candidate for boar fertility. Thus the present research contributes to further elucidating the role of progesterone on the physiological regulation of the most relevant spermatozoa functions for a successful fertilization.

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.

Anticancer activity of a quercetin-based polymer towards HeLa cancer cells

BACKGROUND

Quercetin is one of the most potent antioxidants showing anti-inflammatory, antiproliferative and antitumoral effects; however its short half-life in buffered solution (e.g. body fluids) has so far hampered its introduction into clinical practice.

AIM

To overcome this inconvenience, quercetin was covalently conjugated into a polymethacrylic acid backbone and the conjugate was tested on HeLa cancer cells.

MATERIALS AND METHODS

FT-IR, UV-Vis, Gel Permeation Chromatography analyses and the Folin-Ciocalteu test were performed to characterize the conjugate. Antioxidant properties were assessed by the DPPH test and the viability experiments by trypan blue exclusion assay.

RESULTS

The conjugate showed a functionalization degree of 2.01 mg of Q per g, an IC(50) of 2.62 mg ml(-1) in the DPPH assay and was able to induce a 90% cell death after one day treatment, while the value for free Quercetin was 40% after three days.

CONCLUSION

Polymer conjugation significantly increases quercetin stability, leading to a sustained activity of the flavonoid.

Estrogen receptor beta binds Sp1 and recruits a corepressor complex to the estrogen receptor alpha gene promoter

Human estrogen receptors alpha and beta are crucially involved in the regulation of mammary growth and development. Normal breast tissues display a relative higher expression of ER beta than ER alpha, which drastically changes during breast tumorogenesis. Thus, it is reasonable to suggest that a dysregulation of the two estrogen receptor subtypes may induce breast cancer development. However, the molecular mechanisms underlying the potential opposing roles played by the two estrogen receptors on tumor cell growth remain to be elucidated. In the present study, we have demonstrated that ER beta overexpression in breast cancer cells decreases cell proliferation and down-regulates ER alpha mRNA and protein content, along with a concomitant repression of estrogen-regulated genes. Transient transfection experiments, using a vector containing the human ER alpha promoter region, showed that elevated levels of ER beta down-regulated basal ER alpha promoter activity. Furthermore, site-directed mutagenesis and deletion analysis revealed that the proximal GC-rich motifs at -223 and -214 are critical for the ER beta-induced ER alpha down-regulation in breast cancer cells. This occurred through ER beta-Sp1 protein-protein interactions within the ER alpha promoter region and the recruitment of a corepressor complex containing the nuclear receptor corepressor NCoR, accompanied by hypoacetylation of histone H4 and displacement of RNA-polymerase II. Silencing of NCoR gene expression by RNA interference reversed the down-regulatory effects of ER beta on ER alpha gene expression and cell proliferation. Our results provide evidence for a novel mechanism by which overexpression of ER beta through NCoR is able to down regulate ER alpha gene expression, thus blocking ER alpha's driving role on breast cancer cell growth.

PEG-templated mesoporous silica nanoparticles exclusively target cancer cells

Mesoporous silica nanoparticles (MSNs) have been proposed as DNA and drug delivery carriers, as well as efficient tools for fluorescent cell tracking. The major limitation is that MSNs enter cells regardless of a target-specific functionalization. Here we show that non functionalized MSNs, synthesized using a PEG surfactant-based interfacial synthesis procedure, do not enter cells, while a highly specific, receptor mediated, cellular internalization of folic acid (FOL) grafted MSNs (MSN-FOL), occurs exclusively in folate receptor (FR) expressing cells. Neither the classical clathrin pathway nor macropinocytosis is involved in the MSN endocytic process, while fluorescent MSNs (MSN-FITC) enter cells through aspecific, caveolae-mediated, endocytosis. Moreover, internalized particles seem to be mostly exocytosed from cells within 96 h. Finally, cisplatin (Cp) loaded MSN-FOL were tested on cancerous FR-positive (HeLa) or normal FR-negative (HEK293) cells. A strong growth arrest was observed only in HeLa cells treated with MSN-FOL-Cp. The results presented here show that our mesoporous nanoparticles do not enter cells unless opportunely functionalized, suggesting that they could represent a promising vehicle for drug targeting applications.

The G protein-coupled receptor 30 is up-regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) in breast cancer cells and cardiomyocytes

GPR30, also known as GPER, has been suggested to mediate rapid effects induced by estrogens in diverse normal and cancer tissues. Hypoxia is a common feature of solid tumors involved in apoptosis, cell survival, and proliferation. The response to low oxygen environment is mainly mediated by the hypoxia-inducible factor named HIF-1α, which activates signaling pathways leading to adaptive mechanisms in tumor cells. Here, we demonstrate that the hypoxia induces HIF-1α expression, which in turn mediates the up-regulation of GPER and its downstream target CTGF in estrogen receptor-negative SkBr3 breast cancer cells and in HL-1 cardiomyocytes. Moreover, we show that HIF-1α-responsive elements located within the promoter region of GPER are involved in hypoxia-dependent transcription of GPER, which requires the ROS-induced activation of EGFR/ERK signaling in both SkBr3 and HL-1 and cells. Interestingly, the apoptotic response to hypoxia was prevented by estrogens through GPER in SkBr3 cells. Taken together, our data suggest that the hypoxia-induced expression of GPER may be included among the mechanisms involved in the anti-apoptotic effects elicited by estrogens, particularly in a low oxygen microenvironment.

Inhibition of cyclin D1 expression by androgen receptor in breast cancer cells--identification of a novel androgen response element

Cyclin D1 gene (CCND1) is a critical mitogen-regulated cell-cycle control element whose transcriptional modulation plays a crucial role in breast cancer growth and progression. Here we demonstrate that the non-aromatizable androgen 5-α-dihydrotestosterone (DHT) inhibits endogenous cyclin D1 expression, as evidenced by reduction of cyclin D1 mRNA and protein levels, and decrease of CCND1-promoter activity, in MCF-7 cells. The DHT-dependent inhibition of CCND1 gene activity requires the involvement and the integrity of the androgen receptor (AR) DNA-binding domain. Site directed mutagenesis, DNA affinity precipitation assay, electrophoretic mobility shift assay and chromatin immunoprecipitation analyses indicate that this inhibitory effect is ligand dependent and it is mediated by direct binding of AR to an androgen response element (CCND1-ARE) located at −570 to −556-bp upstream of the transcription start site, in the cyclin D1 proximal promoter. Moreover, AR-mediated repression of the CCND1 involves the recruitment of the atypical orphan nuclear receptor DAX1 as a component of a multiprotein repressor complex also embracing the participation of Histone Deacetylase 1. In conclusion, identification of the CCND1-ARE allows defining cyclin D1 as a specific androgen target gene in breast and might contribute to explain the molecular basis of the inhibitory role of androgens on breast cancer cells proliferation.