Glucocorticoids improve sperm performance in physiological and pathological conditions: their role in sperm fight/flight response

Glucocorticoids play a physiologic role in the adult male reproductive functions, modulating gonadal steroid synthesis and spermatogenesis, through the glucocorticoid receptor (GR). The expression of GR has been described in several key testicular cell types, including somatic cells and early germ cell populations. Nothing is known on GR in human spermatozoa. Herein, we explored the GR expression and its possible role in normal and testicular varicocele semen samples from volunteer donors. After semen parameter evaluation by macro- and microscopic analysis, samples were centrifuged; then spermatozoa and culture media were recovered for further investigations. By western blotting and immunofluorescence analyses we evidenced for the first time in spermatozoa the presence of GR-D3 isoform which was reduced in sperm from varicocele patients. By treating sperm with the synthetic glucocorticoid dexamethasone (DEXA), we found that survival, motility, capacitation, and acrosome reaction were increased in both healthy and varicocele samples. GR involvement in mediating DEXA effects, was confirmed by using the GR inhibitor mifepristone (M2F). Worthy, we also discovered that sperm secretes different cortisol amounts depending on its physio-pathological status, suggesting a defence mechanism to escape the immune system attach in the female genital tract thus maintaining the immune-privilege as in the testis. Collectively, our data suggests a role for glucocorticoids in determining semen quality and function, as well as in participating on sperm immune defensive mechanisms. The novelty of this study may be beneficial and needs to take into account in artificial insemination/drug discovery aimed to enhancing sperm quality.

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.

Glucagon-like Peptide-1 Acts as Signaling Mediator to Modulate Human Sperm Performance via Targeting Akt, JNK and IRS-1 Cell Signaling Cascades: Novel Insights into Sperm Physiopathology

Recent evidence suggests that the male gonad is a potential target of glucagon-like peptide-1 (GLP-1). We investigated the effects of glucagon-like peptide-1 (GLP-1) on sperm function and the molecular mechanisms through which it may act. Semen samples of healthy men were incubated in the presence or absence of a GLP-1 mimetic analog, exendin-4 (Exe). In a different analysis, sperm were exposed to tumor necrosis factor (TNF-α) alone and, in some tubes, TNF-α was added after previous exposure to exendin-4 (Exe). Sperm parameters and protein-kinase B (p-Akt), insulin receptor substrate-1 (p-IRS-1 Ser312), and c Jun N-terminal protein kinase (p-JNK Thr183/Tyr185) were considered and evaluated. Sperm parameters, when incubated for 4 h in a simple defined balanced salt solution lacking protein, declined progressively with incubation time. The maximum decline was associated with a significant decrease in phosphorylated protein kinase B (p-Akt), concomitantly to an increase in insulin receptor substrate-1 (p-IRS-1 Ser312) and c Jun N-terminal protein kinase (p-JNK Thr183/Tyr185). Preincubation with exendin-4 (Exe) prevented this decline and maintained sperm motility (progressive-PM and total-TM). TNF-α exposure resulted in decreased sperm motility (PM and TM) and viability (V) in a concentration-dependent manner. Exe addition attenuated this TNF-α negative effect on sperm parameters. Glucagon-like peptide-1 (GLP-1) also acts by reducing levels of the "negative" kinases p-IRS-1Ser312 and p-JNK. An imbalance involving these three kinases in sperm, as it occurs in somatic cells, is a novel scenario that may participate in sperm physiopathology.

Leptin effects: focusing on the relationship between obesity and male infertility

The human male infertility has several causes interconnected to improper lifestyles such as smoking, sedentarism, environmental factors, toxins accumulation and energy imbalances. All these factors contribute to the obesity accompanied metabolic syndrome and hormonal alterations in the leptin-ghrelin axis. The leptin (Lep) has many pleiotropic effects in several biological systems, directly on the peripheral tissues or through the central nervous system (CNS). Many studies suggest that Lep is a key player in gonadal functions beside its documented role in reproductive regulation, however, further investigations are still necessary to elucidate all the molecular pathways involved in these mechanisms. Keeping into account that increased Lep levels in obese men are positively correlated with altered sperm parameters and testicular oxidative stress, evidences refer to Lep as a potential link between obesity and male infertility. This review represents an updated version on the concept of the Lep roles in mediating the male reproductive functions in obese patients.

FSH-R Human Early Male Genital Tract, Testicular Tumors and Sperm: Its Involvement in Testicular Disorders

The follicle-stimulating hormone receptor (FSH-R) expression was always considered human gonad-specific. The receptor has also been newly detected in extragonadal tissues. In this finding, we evaluated FSH-R expression in the human male early genital tract, in testicular tumors, and in sperm from healthy and varicocele patients. In sperm, we also studied the mechanism of FSH-R action. Immunohystochemistry and Western blot analysis showed FSH-R presence in the first pathways of the human genital tract, in embryonal carcinoma, and in sperm, but it was absent in seminoma and in lower varicocele. In sperm, FSH/FSH-R activity is mediated by G proteins activating the PKA pathway, as we observed by using the H89. It emerged that increasing FSH treatments induced motility, survival, capacitation, and acrosome reaction in both sperm samples. The different FSH-R expression in tumor testicular tissues may be discriminate by tumor histological type. In spermatozoa, FSH-R indicates a direct action of FSH in these cells, which could be beneficial during semen preparation for in vitro fertilization procedures. For instance, FSH positive effects could be relevant in idiopathic infertility and in the clinic surgery of varicocele. In conclusion, FSH-R expression may be considered a molecular marker of testicular disorders.

Sperm performance in oligoasthenoteratozoospermic patients is induced by a nutraceuticals mix, containing mainly myo-inositol

The action of myo-inositol (MI), belonging to the inositol family, has been shown to improve sperm quality. To further elucidate the efficacy of this substance in male fertility, we investigated in vivo the effects of a nutraceuticals mix, containing mainly myo-inositol (MI) and in vitro the action of the MI on human male gamete performance. Sperm samples were evaluated from 51 men: 21 healthy normozoospermic and 30 oligoasthenoteratozoospermic (OAT). In the latter group, 15 patients were orally treated with the nutraceutical mix and in the remaining 15 patients only MI was used directly on their ejaculated sperm. Comparing the pathologic samples with respect to normal samples we observed that motility, viability, Bcl-2 phosphorylation, and cholesterol efflux increased after in vitro and in vivo treatments. Glucose-6-phosphate dehydrogenase activity as well as triglycerides level and lipase activity highlighted an enhancement of energy expenditure upon the treatment. Uncapacitated sperm is characterized by an anabolic metabolism, to generate an energy reservoir which will be spent during the capacitation, an energy-consuming process needed to acquire the competence for the fertilization. Intriguingly, our finding highlights that the treatment with these substances facilitated the switch from uncapacitated to capacitated sperm, promoting the acquisition of the male gamete fertilizing capacity. Our data suggested that these substances act both directly on sperm and on spermatogenesis, improving the performance of OAT sperm invitro and invivo. The positive effects of these treatments could be of great help for men and couples who have difficulty to conceive achild in anatural way and/or during medical-assisted reproduction.Abbreviations: 30 OAT-untreated patients; B: 15 OAT patients treated in vivo; Bovine serum albumin (BSA); C: 15 OAT patients treated in vitro; cholesterol oxidase-peroxidase (CHOD-POD); H: Normozoospermic samples; HM: sperm from normospermic patients treated in vitro with MI; MI: Myoinositol: IM: Immobile motility; NP: Non-progressive motility; OAT: Oligoasthenoteratozoospermic; PPP: Pentose Phosphate Pathway; PR: Progressive motility; WHO: World Health Organization.

Conventional progesterone receptors (PR) B and PRA are expressed by human chondrocytes and can be involved in the pathogenesis of osteoarthritis

To evaluate the expression, location and role of progesterone receptors (PRs) A and B in human chondrocytic cell lines, Western blotting, real time PCR analyses, transmission electron microscopy and immunogold assays were performed. By transfection and co-transfection assays, the influence of progesterone (OHPg) on estrogen receptor alpha (ERα) promoter activity was investigated. MTT and pAKT documented OHPg effects on chondrocytes survival. The PR-B and PR-A were both observed in human chondrocytes. The PR-B was evidenced both in the nucleus and in the cytosol of the cells. OHPg, through PR-B, induced ERα expression by acting at the ER promoter level affecting chondrocytes survival. We reported for the first time the expression of PRs in human chondrocytes. Interestingly, we described a novel mechanism via progesterone induction of ERα, which may explain, at least in part, the dramatic rise in OA prevalence among postmenopausal women.

Peroxisome proliferator-activated receptor gamma expression along the male genital system and its role in male fertility

Peroxisome proliferator-activated receptor gamma (PPARγ) acts as a ligand activated transcription factor and regulates processes, such as energy homeostasis, cell proliferation and differentiation. PPARγ binds to DNA as a heterodimer with retinoid X receptor and it is activated by polyunsaturated fatty acids and fatty acid derivatives, such as prostaglandins. In addition, the insulin-sensitizing thiazolidinediones, such as rosiglitazone, are potent and specific activators of PPARγ. PPARγ is present along the hypothalamic-pituitary-testis axis and in the testis, where low levels in Leydig cells and higher levels in Sertoli cells as well as in germ cells have been found. High amounts of PPARγ were reported in the normal epididymis and in the prostate, but the receptor was almost undetectable in the seminal vesicles. Interestingly, in the human and in pig, PPARγ protein is highly expressed in ejaculated spermatozoa, suggesting a possible role of PPARγ signaling in the regulation of sperm biology. This implies that both natural and synthetic PPARγ ligands may act directly on sperm improving its performance. Given the close link between energy balance and reproduction, activation of PPARγ may have promising metabolic implications in male reproductive functions. In this review, we first describe PPARγ expression in different compartments of the male reproductive axis. Subsequently, we discuss the role of PPARγ in both physiological and several pathological conditions related to the male fertility.

Glucagon-like peptide-1 receptor is expressed in human and rodent testis

BACKGROUND

The incretin hormone glucagon-like peptide-l (GLP-1) is an important regulator of post-prandial insulin secretion, acting through a G protein-coupled cell surface receptor (GLP-1R). In addition to its expression in pancreatic β-cells, several studies suggested that GLP-1R is located in extra-pancreatic tissues.

OBJECTIVES

In this study, we examined for the first time the testicular distribution of the GLP-1R, both in normal human and neoplastic testicular tissues as well as in rodent testis and rodent testicular cell lines.

METHODS AND METHODS

The GLP-1R distribution in testicular section has been evaluated by immunohistochemistry, the specificity of IHC was validated by demonstrating a positive staining for GLP-1RmRNA by RISH technology. While GLP-1R expression in terms of protein was detected by western blot analysis, Moreover, mRNA levels were determined in human testis, in rodent Leydig, and Sertoli cell lines.

RESULTS

Using immunohistochemistrya specific staining for GLP-1R was detected in Leydig cells. The specificity of IHC was validated by demonstrating a positive staining for GLP-1RmRNA only in these cell types. Species differences in the GLP-1R expression between humans and rodents were observed. Interestingly, a decreased expression of the receptor in rodent tumor Leydig cell line and an absence in human Leydig tumor samples was detected.

DISCUSSION

It may be hypothesized that GLP-1R acts like an oncosuppressor in Leydig tumors. A role in regulation of hormone secretion by GLP-1 has been shown in other endocrine cells, therefore we hypothesized that GLP-1R is able to modulate somehow the Leydig cell function.

CONCLUSION

In our findings, a careful evaluation of human testicular tissues and rodent testis revealed Leydig cells as a potential target for GLP-1. Collectively, an effect of GLP-1R in Leydig cell function may be presumed although future studies are needed to ascertain the GLP-1R's role both in normal and tumor Leydig cells.

The Tumor Suppressor PTEN as Molecular Switch Node Regulating Cell Metabolism and Autophagy: Implications in Immune System and Tumor Microenvironment

Recent studies conducted over the past 10 years evidence the intriguing role of the tumor suppressor gene Phosphatase and Tensin Homolog deleted on Chromosome 10 PTEN in the regulation of cellular energy expenditure, together with its capability to modulate proliferation and survival, thus expanding our knowledge of its physiological functions. Transgenic PTEN mice models are resistant to oncogenic transformation, present decreased adiposity and reduced cellular glucose and glutamine uptake, together with increased mitochondrial oxidative phosphorylation. These acquisitions led to a novel understanding regarding the role of PTEN to counteract cancer cell metabolic reprogramming. Particularly, PTEN drives an “anti-Warburg state” in which less glucose is taken up, but it is more efficiently directed to the mitochondrial Krebs cycle. The maintenance of cellular homeostasis together with reduction of metabolic stress are controlled by specific pathways among which autophagy, a catabolic process strictly governed by mTOR and PTEN. Besides, a role of PTEN in metabolic reprogramming and tumor/stroma interactions in cancer models, has recently been established. The genetic inactivation of PTEN in stromal fibroblasts of mouse mammary glands, accelerates breast cancer initiation and progression. This review will discuss our novel understanding in the molecular connection between cell metabolism and autophagy by PTEN, highlighting novel implications regarding tumor/stroma/immune system interplay. The newly discovered action of PTEN opens innovative avenues for investigations relevant to counteract cancer development and progression.

Human Sperm Express the Receptor for Glucagon-like Peptide-1 (GLP-1), Which Affects Sperm Function and Metabolism

AIM

Glucagon-like peptide-1 (GLP-1) produces pleiotropic effects binding to the GLP-1 receptor (GLP1-R), potentiating insulin secretion in the pancreas. GLP1-R is expressed in peripheral tissues and evidence for its role in reproduction has come from knockout mice, although the relationship between GLP-1 and male fertility needs to be clarified. Given that human sperm is an insulin-sensitive and insulin-secreting cell, we hypothesized that the GLP-1/GLP1-R axis may be expressed and functional in these cells.

RESULTS AND DISCUSSION

We revealed the presence of GLP1-R by Western blotting and immunofluorescence analyses. Because Exendin-4 (Ex-4) displays similar functional properties to native GLP-1, we used this agonist to perform a dose-response study on progressive motility and cholesterol efflux, showing that 300 pM Ex-4 was the most effective treatment. These actions are mediated by GLP1-R and independent from sperm-secreted insulin. The exposure to Ex-4 fueled phosphatidylinositol-3-kinase (PI3K)/AKT signaling and was reversed by H89, indicating a protein kinase A (PKA)-dependence of GLP-1/GLP1-R signaling. It emerged that in sperm, insulin secretion regulated by Ex-4 did not occur in a strictly glucose-dependent manner. A stimulatory action of Ex-4/GLP1-R on lactate dehydrogenase and glucose-6-phosphate dehydrogenase (G6PDH) activities was observed. Ex-4/GLP1-R decreased triglycerides content concomitantly to enhanced lipase and acyl-coenzyme A (acyl-CoA) dehydrogenase activities, addressing a lipolytic effect.

CONCLUSION

Collectively, we discovered that human sperm is a new GLP1 incretin target, broadening our knowledge about the effects of the GLP1-R agonist in the male reproductive field. Further findings in humans should be conducted in the future to confirm it and to improve the translational aspect of this study.

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.

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.

Activated-farnesoid X receptor (FXR) expressed in human sperm alters its fertilising ability

The farnesoid X receptor alpha (FXR) is a bile acid sensor activated by binding to endogenous bile acids including chenodeoxycholic acid (CDCA). Although, FXR is expressed in male reproductive tissue, the relevance of the receptor on reproduction is scarcely known. Here, we demonstrated the FXR presence and its action on several human sperm features. Western blot and immunofluorescence assays evidenced the FXR expression in human spermatozoa and the localisation in the middle piece. CDCA increasing concentrations and GW4064, synthetic ligand of FXR, were used to study the FXR influence on sperm motility, survival, capacitation, acrosome reaction and on glucose as well as lipid metabolism. Interestingly, our data showed that increasing concentrations of CDCA negatively affected sperm parameters, while the receptor blockage by (Z)-Guggulsterone and by the anti-FXR Ab reversed the effects. Intriguingly, elevated CDCA levels increased triglyceride content, while lipase and G6PDH activities were reduced with respect to untreated samples, thus impeding the metabolic reprogramming typical of the capacitated sperm. In conclusion, in this study, we demonstrated for the first time a novel target for FXR and that the activated receptor alters the acquisition of sperm fertilising ability. We showed that sperm itself express the FXR and it is responsive to specific ligands of the receptor; therefore, bile acids influence this cell both in male and in female genital tracts. It might be hypothesized that bile acid levels could be involved in infertility with idiopathic origin as these compounds are not systematically measured in men undergoing medically assisted procreation.

Immunolocalization of G Protein-Coupled Estrogen Receptor in the Pig Epididymis

The presence of estrogen in the genital ducts of different mammalian species has been extensively studied and the estrogen influence on the functional activity of the male genital tract has been hypothesized. Conversely, very few data have been reported on pig excurrent ducts: the localization of classical estrogen receptors (ERα and ERβ) is scarcely known, while the expression of the G protein-coupled receptor (GPER1), a membrane estrogen receptor, is still unknown in pig. The aim of the present study was to evaluate GPER1 expression in the different regions of the mature pig epididymis, using immunohistochemistry, western blot and RT-PCR analyses. The results showed that GPER1 is mainly expressed in the epithelial cells of the corpus epididymis compared to the caput and the cauda, while muscle cells are moderately immunostained and stromal cells are unstained. The presence of GPER1 was confirmed by Western blot and RT-PCR analyses. In our study, we have demonstrated for the first time the GPER1 expression in male porcine epididymis, revealing a new mediator of estrogen signaling at this site. In conclusion, these new data suggest that estrogen action via GPER1 may contribute to sperm maturation in the corpus and sperm protection/storage in the cauda. Interestingly, the presence of GPER1 in the muscle layer may be indicative of a possible GPER1 involvement in the estrogen regulation of duct contractility. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.

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.

Estradiol via estrogen receptor beta influences ROS levels through the transcriptional regulation of SIRT3 in human seminoma TCam-2 cells

Human testis, gonocytes, and adult germ cells mainly express estrogen receptor beta, and estrogen receptor beta loss is associated with advanced tumor stage; however, the molecular mechanisms of estrogen receptor beta-protective effects are still to be defined. Herein, we provide evidence that in human seminoma TCam-2 cells, E2 through estrogen receptor beta upregulates the mitochondrial deacetylase sirtuin-3 at protein and messenger RNA levels. Specifically, E2 increases sirtuin-3 expression through a transcriptional mechanism due to the occupancy of sirtuin-3 promoter by estrogen receptor beta, together with the transcription factor Sp1 as evidenced by Chip reChIp assay. This complex binds to a GC cluster located between -128 bp/+1 bp and is fundamental for E2 effects, as demonstrated by Sp1 small interfering RNA studies. Beside, after 24 h, E2 stimulus significantly increased activities of superoxide dismutase and catalase to scavenge reactive oxygen species produced by 30 min of E2 stimulus. In summary, this article indicates a novel functional interplay between estrogen receptor beta and sirtuin-3 counteracting reactive oxygen species production in TCam-2 cells. Our findings thus show that an important tumor-suppressive pathway through estrogen receptor beta is target of E2, actually proposing a distinctive protecting action against seminoma. Future studies may lead to additional strategies for the current therapy of seminoma.

Exosomes in human atherosclerosis: An ultrastructural analysis study

Cell-to-cell communication, or signaling, is absolutely essential in orchestrating the activities of cells in multicellular organisms, to grow, develop, detect environmental changes and compensate for them in an internal, coordinated fashion. In the last few years, a considerable amount of new data have demonstrated the occurrence of a sophisticated intercellular signaling pathway based on the release of specialized vesicular structures, called exosomes, whose secretion appears to be regulated by various natural and experimental stimuli, physiological states, and disease processes. In the cardiovascular system, the study of exosomes is still in its infancy. Here, we aim to provide the first ultrastructural evidence for the presence of exosomes in human atherosclerotic plaque. We demonstrate by means of transmission electron microscopy that both lesional smooth muscle cells and endothelial cells are able to generate these membraneous microvesicles within specific compartments of the cell, called multivesicular bodies. Notably, in our series no signs of apoptosis have been detected in vascular cells secreting exosomes and no evidence of calcification has been observed associated with these structures in the extracellular space. Our results suggest the possible existence of a new mechanism of intercellular communication in the plaque milieu.

Steroid receptors in human ejaculated sperm as molecular markers of the detrimental effects related to the pathophysiology of testicular varicocele

The exact physiopathologic effect of testicular varicocele on male fertility is not defined yet. The detrimental role of the varicocele in fertility is supported by the presence of a higher frequency of affected men among the infertile population. However, the mechanism/s by which a varicocele impairs sperm production, structure and function, is not known. In spite of active interest, our understanding of the human male gamete ultrastructural molecular organisation is still incomplete and therefore our knowledge of the sperm molecular anatomy is very limited. The presence of steroid binding sites on human spermatozoa has been evidenced since the 1970s, and afterwards, spermatozoa physiology was linked to the action of different steroids. The presence of steroid/steroid receptor systems was demonstrated in mature spermatozoa as membrane but also as nuclear conventional receptors, suggesting that both systemic and local steroids, through sperm receptors, may influence male fertility. From new data, it emerges that varicocele may induce damage in the male gamete at molecular level, opening a new chapter in the already multifactorial pathophysiology of the varicocele, complicating this issue. In sperm from varicocele, a decreased expression of steroid receptors and a consequent reduced responsiveness to steroids may represent a mechanism involved in the physiopathology of varicocele. Therefore, the modulation of these nuclear receptors pave the way for novel therapeutic opportunities in the treatment of the male pathologies related to human reproduction. The purpose of this review is to gain new insight into the physiopathology of varicocele and to study its impact on human sperm molecular anatomy.

Recombinant Arabidopsis HSP70 Sustains Cell Survival and Metastatic Potential of Breast Cancer Cells

The chaperone HSP70 protein is widely present in many different tumors and its expression correlates with an increased cell survival, low differentiation, and poor therapeutic outcome in human breast cancer. The intracellular protein has prevalently a cytoprotective function, while the extracellular HSP70 mediates immunologic responses. Evolutionarily, HSPs are well conserved from prokaryotes to eukaryotes, and human HSP70 shows a strong similarity to that of plant origin. In the current article, we have tested the potential effect of recombinant HSP70, from Arabidopsis thaliana, on cell survival and metastatic properties of breast cancer cells. Our data show that HSP70 sustains cell viability in MCF-7 and MDA-MB-231 breast tumoral cells and increases Cyclin D1 and Survivin expression. The extracellular HSP70 triggers cell migration and the activation of MMPs particularly in MDA-MB-231 cells. Furthermore, under UV-induced stress condition, the low levels of phospho-AKT were increased by exogenous HSP70, together with the upregulation of Cyclin D1, particularly in the tumoral cell phenotype. On the other hand, UV increased TP53 expression, and the coincubation of HSP70 lowers the TP53 levels similar to the control. These findings correlate with the cytoprotective and antiapoptotic role of HSPs, as reported in different cellular contexts. This is the first study on mammary cells that highlights how the heterologous HSP70 from Arabidopsis thaliana sustains cell survival prevalently in breast cancer cell types, thus maintaining their metastatic potential. Therefore, targeting HSP70 would be of clinical importance since HSP70 blocking selectively targets tumor cells, in which it supports cell growth and survival. Mol Cancer Ther; 15(5); 1063-73. ©2016 AACR.

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.

PTEN ELEVATION, AUTOPHAGY AND METABOLIC REPROGRAMMING MAY BE INDUCED IN HUMAN CHONDROCYTES DURING STEROIDS OR NUTRIENT DEPLETION AND OSTEOARTHRITIS

The exact mechanisms controlling the development and progression of osteoarthritis have not yet been clarified. Our aim was to investigate new pathomechanisms, with an emphasis on novel molecular targets that might regulate human chondrocytes in osteoarthritis. As a model for studying cell survival and metabolism, C-28/I2 and T/C-28a4 human chondrocytes were grown in complete medium, in dex-tran-coated charcoal treated medium and in serum-free medium. Healthy and osteoarthritic human cartilage samples were obtained from discarded surgical material. Cell survival, PTEN, AKT, Beclin1, AMBRA, AMPK and glucose/triglyceride metabolism were evaluated by immunoblotting and spectro-photometric assays. Starvation and steroids depletion decreased cell survival concomitantly with PTEN elevation, repression of the PI3K/AKT signaling axis and autophagy activation. These experimental conditions promoted the accumulation of glucose, decreased levels of G6PDH and resulted in differen-tial expression of OXPHOS complexes. Furthermore, they induced the expression of AMPK, reduced triglyceride levels and increased lipase activity, which was accompanied by a change in chondrocytes toward a fibroblast-like morphology. In osteoarthritic human cartilage, increased PTEN, AMPK and autophagy reflected the chondrocyte responses observed during starvation and steroids depletion. In conclusion, we defined the metabolic phenotype of human chondrocytes, in which both starvation and steroids depletion induce the activation of PTEN, AMPK and autophagy signaling, concomitant with metabolic reprogramming. Our data may aid in the development of novel in vitro models for the discovery and design of drugs or nutraceuticals capable of ameliorating the course of osteoarthritis.

Human sperm liver receptor homolog-1 (LRH-1) acts as a downstream target of the estrogen signaling pathway

In the last decade, the study of human sperm anatomy, at molecular level, has revealed the presence of several nuclear protein receptors. In this work, we examined the expression profile and the ultrastructural localization of liver receptor homolog-1 (LRH-1) in human spermatozoa. We evidenced the presence of the receptor by Western blotting and real time-RT-PCR. Furthermore, we used immunogold electron microscopy to investigate the sperm anatomical regions containing LRH-1. The receptor was mainly located in the sperm head, whereas its expression was reduced in the neck and across the tail. Interestingly, we observed the presence of LRH-1 in different stages of testicular germ cell development by immunohistochemistry. In somatic cells, it has been suggested that the LRH-1 pathway is tightly linked with estrogen signaling and the important role of estradiol has been widely studied in sperm cells. To assess the significance of LRH-1 in male gametes and to deepen understanding of the role of estrogens in these cells, we investigated important sperm features such as motility, survival and capacitation. Spermatozoa were treated with 10 nm estradiol and the inhibition of LRH-1 reversed the estradiol stimulatory action. From our data, we discovered that human spermatozoa can be considered a new site of expression for LRH-1, evidencing its role in sperm motility, survival and cholesterol efflux. Furthermore, we may presume that in spermatozoa the LRH-1 effects are closely integrated with the estrogen signaling, supporting LRH-1 as a downstream effector of the estradiol pathway on some sperm functions.

Bergapten drives autophagy through the up-regulation of PTEN expression in breast cancer cells

Background

Bergapten (5-methoxypsoralen), a natural psoralen derivative present in many fruits and vegetables, has shown antitumoral effects in a variety of cell types. In this study, it has been addressed how Bergapten in breast cancer cells induces autophagic process.

Results

In MCF7 and ZR-75 breast cancer cells Bergapten exhibited anti-survival response by inducing the autophagic process increasing Beclin1, PI3KIII, UVRAG, AMBRA expression and conversion of LC3-I to LC3-II. LC3-GFP, Acridine orange assay and transmission electron microscopy even confirmed the increased autophagosome formations in treated cells. Bergapten-induced autophagy is dependent by PTEN up-regulation, since silencing this gene, the induction of Beclin1 and the p-AKT/p-mTOR signal down-regulation were reversed. PTEN is transcriptionally regulated by Bergapten through the involvement of p38MAPK/NF-Y, as evidenced by the use of p38MAPK inhibitor SB203580, site-direct mutagenesis of NF-Y element and NF-Y siRNA. Furthermore NF-Y knockdown prevented Bergapten-induced acid vesicular organelle accumulations (AVOs), strengthening the role of this element in mediating autophagy.

Conclusions

Our data indicate PTEN as a key target of Bergapten action in breast cancer cells for the induction of autophagy. These findings add further details on the mechanism of action of Bergapten, therefore suggesting that phytochemical compounds may be implemented in the novel strategies for breast cancer treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0403-4) contains supplementary material, which is available to authorized users.

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.

HIF-1α and VEGF: Immunohistochemical Profile and Possible Function in Human Aortic Valve Stenosis

Calcific aortic stenosis (CAS) is the most common valvular disease in Western countries. Histological findings in patients with CAS extremely resemble those of atherosclerosis and include accumulation and modification of lipoproteins, inflammation, extracellular matrix remodeling, and calcification. Angiogenesis is another prominent feature of CAS; however, there is only a limited amount of data available regarding the mechanisms behind the pathological neovascularization of a structure that is originally avascular. The present study aims to identify the molecular basis that regulates blood vessel growth in stenotic aortic valves, focusing on the role of HIF-1α and VEGF pathway. A total of 19 native degenerating aortic valves obtained at valve replacement surgery have been processed for Western blot, immunohistochemical, morphometric, and ultrastructural analyses. First, we have demonstrated the adverse ECM remodeling and the significant thickening of the leaflet also showing that HIF-1α and VEGF are significantly upregulated in the stenotic valves, are locally produced and colocalize with angiogenesis and areas of calcification. Next, we have characterized, for the first time to the best of our knowledge, the morphological features of the neovasculature evidencing the presence of intact blood vessels in close proximity to the mineralized zones. These results suggest that the complex structural remodeling of the matrix might reduce oxygen availability in the valve cusp contributing to the stabilization of HIF-1α that in turn induces a metabolic adaptation through the upregulation of VEGF and the formation of new blood vessels not only to overcome the hypoxic state but also to sustain the calcification process.

A novel functional interplay between Progesterone Receptor-B and PTEN, via AKT, modulates autophagy in breast cancer cells

The tumour suppressor activity of the phosphatase and tensin homologue on chromosome 10 (PTEN) is subject of intense investigative efforts, although limited information on its regulation in breast cancer is available. Herein, we report that, in breast cancer cells, progesterone (OHPg), through its cognate receptor PR-B, positively modulates PTEN expression by inducing its mRNA and protein levels, and increasing PTEN-promoter activity. The OHPg-dependent up-regulation of PTEN gene activity requires binding of the PR-B to an Sp1-rich region within the PTEN gene promoter. Indeed, ChIP and EMSA analyses showed that OHPg treatment induced the occupancy of PTEN promoter by PR and Sp1 together with transcriptional coactivators such as SRC1 and CBP. PR-B isoform knockdown abolished the complex formation indicating its specific involvement. The OHPg/PR-B dependent induction of PTEN causes the down-regulation of PI3K/AKT signal, switching on the autophagy process through an enhanced expression of UVRAG and leading to a reduced cell survival. Altogether these findings highlight a novel functional connection between OHPg/PR-B and tumour suppressor pathways in breast cancer.

Expression profile and subcellular localization of GAPDH in the smooth muscle cells of human atherosclerotic plaque: an immunohistochemical and ultrastructural study with biological therapeutic perspectives

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has long been considered a classical glycolytic enzyme involved exclusively in cytosolic energy production. Several recent studies, however, have demonstrated that GAPDH is a multifunctional protein whose presence and activity can be regulated by disease states and/or experimental manipulation. Expression levels of GAPDH have been shown to be altered in certain tumors as well as in proliferating and differentiating cells. Since dedifferentiation and proliferation of smooth muscle cells (SMCs) are important features of human atherosclerosis, we have characterized the expression profile of GAPDH in the SMCs of atherosclerotic plaques and its putative interrelationship with the synthetic/proliferative status of these cells utilizing the proliferating cell nuclear antigen (PCNA) antibody, a valuable marker of cell proliferation. Western blot data revealed that GAPDH was significantly upregulated in atherosclerotic plaque specimens. Immunohistochemical stains demonstrated that GAPDH accumulated in the nucleus of dedifferentiated SMCs that also showed positive immunoreactivity for PCNA, but remained cytoplasmatic in the contractile SMCs (PCNA-negative), thus reflecting the proliferative, structural and synthetic differences between them. We suggest that, in human atherosclerotic plaque, GAPDH might exert additional functions that are independent of its well-documented glycolytic activity and might play key roles in development of the disease.

Steroid receptors and their ligands: effects on male gamete functions

In recent years a new picture of human sperm biology is emerging. It is now widely recognized that sperm contain nuclear encoded mRNA, mitochondrial encoded RNA and different transcription factors including steroid receptors, while in the past sperm were considered incapable of transcription and translation. One of the main targets of steroid hormones and their receptors is reproductive function. Expression studies on Progesterone Receptor, estrogen receptor, androgen receptor and their specific ligands, demonstrate the presence of these systems in mature spermatozoa as surface but also as nuclear conventional receptors, suggesting that both systemic and local steroid hormones, through sperm receptors, may influence male reproduction. However, the relationship between the signaling events modulated by steroid hormones and sperm fertilization potential as well as the possible involvement of the specific receptors are still controversial issues. The main line of this review highlights the current research in human sperm biology examining new molecular systems of response to the hormones as well as specific regulatory pathways controlling sperm cell fate and biological functions. Most significant studies regarding the identification of steroid receptors are reported and the mechanistic insights relative to signaling pathways, together with the change in sperm metabolism energy influenced by steroid hormones are discussed.The reviewed evidences suggest important effects of Progesterone, Estrogen and Testosterone and their receptors on spermatozoa and implicate the involvement of both systemic and local steroid action in the regulation of male fertility potential.

Human sperm anatomy and endocrinology in varicocele: role of androgen receptor

The study of androgens involved in male reproduction has been object of intense efforts, while their reported action on human male gametes is limited. We previously described the presence of androgen receptor (AR) in sperm with a role related to the modulation of the PI3K pathway. In the present study, we investigated the expression of AR and its ultrastructural location in normal sperm as well as in spermatozoa obtained from varicocele patients. We observed a reduced AR content in varicocele sperm with respect to healthy sperm by western blot analysis and transmission electron microscopy (TEM). The ultrastructural location of AR was detected mainly on the head membrane as well as in the nucleus, neck, and mitochondria. Influence of dihydrotestosterone (DHT) treatment on cholesterol efflux was increased in normal sperm, while it was reduced or absent in varicocele sperm. To better understand DHT/AR significance in human male gametes, we evaluated triglyceride content and lipase, acyl-CoA dehydrogenase, and glucose-6-phosphate dehydrogenase activities upon DHT treatment. The metabolic outcome glimpsed in normal sperm was an increased metabolic rate, while ‘varicocele’ sperm economized energy. Taken together, our results reveal DHT and AR as new players in sperm endocrinology, indicating that varicocele sperm may have difficulty in switching to the capacitated status. A decreased AR expression and a consequent reduced responsiveness to DHT in sperm may represent molecular mechanisms involved in the pathophysiology of varicocele leading to male infertility. This study revealed new detrimental effects of varicocele on sperm at the molecular level.

Identification of G protein-coupled estrogen receptor in human and pig spermatozoa

Estrogens are known to influence functional properties of mammalian spermatozoa inducing rapid responses through the classical estrogen receptors (ERα and ERβ). Recently, the G protein-coupled estrogen receptor (GPER) has been identified as mediator of fast non-genomic estrogen effects in different cells. This work investigated the expression of GPER in human and pig spermatozoa using immunofluorescence, Western blot analysis and RT-PCR. GPER was found to be confined to the mid-piece of human sperm cells, whereas it was detected in the acrosomal region, the equatorial segment and the mid-piece of pig spermatozoa. Furthermore, in the male gametes of both species, the immunoblots of sperm extracts revealed a band at ~42 kDa, consistent with the GPER molecular weight, and RT-PCR detected the GPER transcripts. This is the first report demonstrating the expression of GPER in human and pig mature sperm cells and evidencing its species-specific cellular localization.

Internal mammary artery atherosclerosis: an ultrastructural study of two cases

Atherosclerosis of the internal mammary artery (IMA) is generally regarded as a rare (but existent) pathological entity with only a few cases reported in the most recent literature. The only study which to our knowledge has investigated the ultrastructural features of IMA atherosclerosis, demonstrate the presence of endothelial cells loss, defects of internal elastic lamina with no evidence of lipid accumulation. In the present study, we describe two cases of IMA atherosclerosis in which ultrastructural analysis revealed the presence of a typical atherosclerotic plaque morphology with infiltration of inflammatory cells, formation of intraplaque lipid pools, and accumulation of lipid-laden foam cells throughout the thickened intima, never described in this rare lesion before. Microscopically, the lesions were also characterized by intimal thickening, invagination of endothelial cells, migration of smooth muscle cells with splitting, fenestration and/or fragmentation of the elastic sheets. Our observations add new data to the scarce and contradictory literature and to this largely understudied vascular disorder.

T3 enhances thyroid cancer cell proliferation through TRβ1/Oct-1-mediated cyclin D1 activation

Several studies have demonstrated that thyroid hormone T3 promotes cancer cell growth, even though the molecular mechanism involved in such processes still needs to be elucidated. In this study we demonstrated that T3 induced proliferation in papillary thyroid carcinoma cell lines concomitantly with an up-regulation of cyclin D1 expression, that is a critical mitogen-regulated cell-cycle control element. Our data revealed that T3 enhanced the recruitment of the TRβ1/Oct-1 complex on Octamer-transcription factor-1 site within cyclin D1 promoter, leading to its transactivation. In addition, silencing of TRβ1 or Oct-1 expression by RNA interference reversed both increased cell proliferation and up-regulation of cyclin D1, underlying the important role of both transcriptional factors in mediating these effects. Finally, T3-induced increase in cell growth was abrogated after knocking down cyclin D1 expression. All these findings highlight a new molecular mechanism by which T3 promotes thyroid cancer cell growth.

Epigallocatechin gallate inhibits growth and epithelial-to-mesenchymal transition in human thyroid carcinoma cell lines

Well-differentiated papillary and follicular thyroid carcinoma are the most frequent types of thyroid cancer and the prognosis is generally favorable however, a number of patients develops recurrences. Epigallocatechin-3-gallate (EGCG), a major catechin in green tea, was shown to possess remarkable therapeutic potential against various types of human cancers, although data on thyroid cancer cells are still lacking. The aim of this study was to investigate the effect of EGCG on the proliferation and motility of human thyroid papillary (FB-2) and follicular (WRO) carcinoma cell lines. Our results demonstrate that EGCG (10, 40, 60 μM) treatment inhibited the growth of FB-2 and WRO cells in a dose-dependent manner. These changes were associated with reduced cyclin D1, increased p21 and p53 expression. Furthermore, EGCG suppressed phosphorylation of AKT and ERK1/2. In addition EGCG treatment results in reduction of cell motility and migration. Changes in motility and migration in FB-2 were associated with modulation in the expression of several proteins involved in cell adhesion and reorganization of actin cytoskeleton. After 24 h EGCG caused an increase of the E-cadherin expression and a concomitant decrease of SNAIL, ZEB and the basic helix-loop-helix transcription factor TWIST. Besides expression of Vimentin, N-cadherin and α5-integrin was down-regulated. These data well correlate with a reduction of MMP9 activity as evidenced by gelatin zymography. Our findings support the inhibitory role of EGCG on thyroid cancer cell proliferation and motility with concomitant loss of epithelial-to-mesenchymal cell transition markers.

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.

The nuclear localization signal is required for nuclear GPER translocation and function in breast Cancer-Associated Fibroblasts (CAFs)

Cancer associated fibroblasts (CAFs) actively contribute to the growth and invasion of cancer cells. In recent years, the G protein estrogen receptor (GPER) has been largely involved in the estrogenic signals in diverse types of normal and tumor cells. In CAFs, GPER was localized into the nucleus, however the molecular mechanisms which regulate its nuclear shuttle remain to be clarified. In the present study, we demonstrate that in breast CAFs GPER translocates into the nucleus through an importin-dependent mechanism. Moreover, we show that a nuclear localization signal is involved in the nuclear import of GPER, in the up-regulation of its target genes c-fos and CTGF and in the migration of CAFs induced by estrogens. Our data provide novel insights into the nuclear localization and function of GPER in CAFs toward a better understanding of the estrogen action elicited through these key players of the tumor microenvironment.

Insulin affects sperm capacity in pig through nitric oxide

Insulin (Ins) has recently been demonstrated to have the ability to induce the capacitation process in pig spermatozoa. In various mammalian species, capacitation has been linked to the nitric oxide (NO) signalling; therefore, this study investigated NO production in Ins-treated pig spermatozoa by fluorescence-activated cell sorting. For the same samples, sperm capacitation was evaluated by chlortetracycline staining, protein tyrosine phosphorylation pattern and acrosomal status. A significant increase of the intrasperm NO level and the activation of three capacitation indices were detected in response to Ins treatment. Conversely, sperm preincubation with an NO synthase inhibitor (N-nitro-L-arginine methyl ester) or with the anti-Ins receptor β (IRβ) antibody reversed all of the Ins-related effects. These results suggest that Ins has the capacity to enhance intracellular NO concentrations in pig spermatozoa and indicate a possible NO implication upon Ins promotion of capacitation.

Mitochondrial fission induces glycolytic reprogramming in cancer-associated myofibroblasts, driving stromal lactate production, and early tumor growth

Recent studies have suggested that cancer cells behave as metabolic parasites, by inducing oxidative stress in adjacent normal fibroblasts. More specifically, oncogenic mutations in cancer cells lead to ROS production and the "secretion" of hydrogen peroxide species. Oxidative stress in stromal fibroblasts then induces their metabolic conversion into cancer-associated fibroblasts. Such oxidative stress drives the onset of autophagy, mitophagy, and aerobic glycolysis in fibroblasts, resulting in the local production of high-energy mitochondrial fuels (such as L-lactate, ketone bodies, and glutamine). These recycled nutrients are then transferred to cancer cells, where they are efficiently burned via oxidative mitochondrial metabolism (OXPHOS). We have termed this new energy-transfer mechanism "Two-Compartment Tumor Metabolism", to reflect that the production and consumption of nutrients (L-lactate and other catabolites) is highly compartmentalized. Thus, high-energy onco-catabolites are produced by the tumor stroma. Here, we used a genetic approach to stringently test this energy-transfer hypothesis. First, we generated hTERT-immortalized fibroblasts which were genetically re-programmed towards catabolic metabolism. Metabolic re-programming towards glycolytic metabolism was achieved by the recombinant over-expression of MFF (mitochondrial fission factor). MFF over-expression results in extensive mitochondrial fragmentation, driving mitochondrial dysfunction. Our results directly show that MFFfibroblasts undergo oxidative stress, with increased ROS production, and the onset of autophagy and mitophagy, both catabolic processes. Mechanistically, oxidative stress induces autophagy via NF-kB activation, also providing a link with inflammation. As a consequence MFF-fibroblasts showed intracellular ATP depletion and the extracellular secretion of L-lactate, a critical onco-catabolite. MFF-fibroblasts also showed signs of myofibroblast differentiation, with the expression of SMA and calponin. Importantly, MFF-fibroblasts signficantly promoted early tumor growth (up to 6.5-fold), despite a 20% overall reduction in angiogenesis. Thus, catabolic metabolism in cancer-associated fibroblasts may be a critical event during tumor intiation, allowing accelerated tumor growth, especially prior to the onset of neoangiogenesis.

In vitro mechanism for downregulation of ER-α expression by epigallocatechin gallate in ER+/PR+ human breast cancer cells

SCOPE

Exposure of the breast to estrogens and other sex hormones is an important cancer risk factor and estrogen receptor downregulators are attracting significant clinical interest. Epigallocatechin gallate (EGCG), a polyphenolic compound found in green tea, has gained considerable attention for its antitumor properties. Here we aimed to investigate the molecular mechanisms through which EGCG regulates ER-α expression in ER+ PR+ breast cancer cells.

MATERIAL AND METHODS

Western blotting analysis, real-time PCR, and transient transfections of deletion fragments of the ER-α gene promoter show that EGCG downregulates ER-α protein, mRNA, and gene promoter activity with a concomitant reduction of ER-α genomic and nongenomic signal. These events occur through p38(MAPK) /CK2 activation, causing the release from Hsp90 of progesterone receptor B (PR-B) and its consequent nuclear translocation as evidenced by immunofluorescence studies. EMSA, and ChIP assay reveal that, upon EGCG treatment, PR-B is recruited at the half-PRE site on ER-α promoter. This is concomitant with the formation of a corepressor complex containing NCoR and HDAC1 while RNA polymerase II is displaced. The events are crucially mediated by PR-B isoform, since they are abrogated with PR-B siRNA.

CONCLUSION

Our data provide evidence for a mechanism by which EGCG downregulates ER-α and explains the inhibitory action of EGCG on the proliferation of ER+ PR+ cancer cells tested. We suggest that the EGCG/PR-B signaling should be further exploited for clinical approach.