sRAGE downregulates the VEGF expression in OHSS ovarian granulosa cells

OBJECTIVE

Ovarian hyperstimulation syndrome (OHSS) is mainly caused by human chorionic gonadotropin (hCG) through vasoactive mediators such as vascular endothelial growth factor (VEGF) and various inflammatory factors. Our previous study showed that soluble receptor for advanced glycation end products (sRAGE) played a protective role in PCOS by inhibiting VEGF, so wanted to explore the role of sRAGE in OHSS.

METHODS

Two sets of experiments were performed in this study. In part one, sRAGE protein levels in follicular fluid (FF) samples from 60 patients with OHSS and 60 non-OHSS patients were measured by ELISA. In part two, ovarian granulosa cells were isolated from an additional 25 patients with OHSS and cultured. Then, ovarian granulosa cells were treated with different concentrations of sRAGE. Granulosa cells cultured without sRAGE stimulation were used as the control group. The levels of VEGF, amphiregulin (AREG), betacellulin (BTC), and epiregulin (EREG) mRNA were examined by quantitative RT-PCR. The protein levels of VEGF, AREG, BTC, and EREG were measured by ELISA.

RESULTS

Compared with non-OHSS patients, patients with OHSS exhibited lower sRAGE levels in both serum and FF (p < .05). Treatment with sRAGE decreased the production of VEGF, and the effects were dependent on the concentration of sRAGE (p < .05). Simultaneously, the expression of the EGF-like growth factors AREG, BTC and EREG was decreased, and their expression was dependent on the concentration of sRAGE (p < .05).

CONCLUSIONS

sRAGE downregulate VEGF expression in OHSS ovarian granulosa cells, in which EGF-like growth factor pathway may be involved, and sRAGE may play a potential protective role in OHSS.

Oral immune dysfunction is associated with the expansion of FOXP3+PD-1+Amphiregulin+ T cells during HIV infection

Residual systemic inflammation and mucosal immune dysfunction persist in people living with HIV, despite treatment with combined anti-retroviral therapy, but the underlying immune mechanisms are poorly understood. Here we report that the altered immune landscape of the oral mucosa of HIV-positive patients on therapy involves increased TLR and inflammasome signaling, localized CD4+ T cell hyperactivation, and, counterintuitively, enrichment of FOXP3+ T cells. HIV infection of oral tonsil cultures in vitro causes an increase in FOXP3+ T cells expressing PD-1, IFN-γ, Amphiregulin and IL-10. These cells persist even in the presence of anti-retroviral drugs, and further expand when stimulated by TLR2 ligands and IL-1β. Mechanistically, IL-1β upregulates PD-1 expression via AKT signaling, and PD-1 stabilizes FOXP3 and Amphiregulin through a mechanism involving asparaginyl endopeptidase, resulting in FOXP3+ cells that are incapable of suppressing CD4+ T cells in vitro. The FOXP3+ T cells that are abundant in HIV-positive patients are phenotypically similar to the in vitro cultured, HIV-responsive FOXP3+ T cells, and their presence strongly correlates with CD4+ T cell hyper-activation. This suggests that FOXP3+ T cell dysregulation might play a role in the mucosal immune dysfunction of HIV patients on therapy.

Amphiregulin increases migration and proliferation of epithelial ovarian cancer cells by inducing its own expression via PI3-kinase signaling

The epidermal growth factor receptor (EGFR) is overexpressed in many types of cancer, including epithelial ovarian cancer (EOC), and its expression has been found to correlate with advanced stage and poor prognosis. The EGFR ligand amphiregulin (AREG) has been investigated as a target for human cancer therapy and is known to have an autocrine role in many cancers. A cytokine array identified AREG as one of several cytokines upregulated by EGF in a phosphatidylinositol 3-kinase (PI3-K) dependent manner in EOC cells. To investigate the functional role of AREG in EOC, its effect on cellular migration and proliferation was assessed in two EOC cells lines, OV167 and SKOV3. AREG increased both migration and proliferation of EOC cell line models through activation of PI3-K signaling, but independent of mitogen activated protein kinase (MAPK) signaling. Through an AREG autocrine loop mediated via PI3-K, upregulation of AREG led to increased levels of both AREG transcript and secreted AREG, while downregulation of endogenous AREG decreased the ability of exogenous AREG to induce cell migration and proliferation. Further, inhibition of endogenous AREG activity or metalloproteinase activity decreased EGF-induced EOC migration and proliferation, indicating a role for soluble endogenous AREG in mediating the functional effects of EGFR in inducing migration and proliferation in EOC.

Pulmonary fibrosis distal airway epithelia are dynamically and structurally dysfunctional

The airway epithelium serves as the interface between the host and external environment. In many chronic lung diseases, the airway is the site of substantial remodeling after injury. While, idiopathic pulmonary fibrosis (IPF) has traditionally been considered a disease of the alveolus and lung matrix, the dominant environmental (cigarette smoking) and genetic (gain of function MUC5B promoter variant) risk factor primarily affect the distal airway epithelium. Moreover, airway-specific pathogenic features of IPF include bronchiolization of the distal airspace with abnormal airway cell-types and honeycomb cystic terminal airway-like structures with concurrent loss of terminal bronchioles in regions of minimal fibrosis. However, the pathogenic role of the airway epithelium in IPF is unknown. Combining biophysical, genetic, and signaling analyses of primary airway epithelial cells, we demonstrate that healthy and IPF airway epithelia are biophysically distinct, identifying pathologic activation of the ERBB-YAP axis as a specific and modifiable driver of prolongation of the unjammed-to-jammed transition in IPF epithelia. Furthermore, we demonstrate that this biophysical state and signaling axis correlates with epithelial-driven activation of the underlying mesenchyme. Our data illustrate the active mechanisms regulating airway epithelial-driven fibrosis and identify targets to modulate disease progression.

In vivo silencing of amphiregulin by a novel effective Self-Assembled-Micelle inhibitory RNA ameliorates renal fibrosis via inhibition of EGFR signals

Amphiregulin (AREG) is a transmembrane glycoprotein recently implicated in kidney fibrosis. Previously, we reported that the AREG-targeting Self-Assembled-Micelle inhibitory RNA (SAMiRNA-AREG) alleviated fibrosis by stably silencing the AREG gene, and reduced the side effects of conventional siRNA treatment of pulmonary fibrosis. However, the therapeutic effect of SAMiRNA-AREG in renal fibrosis has not been studied until now. We used two animal models of renal fibrosis generated by a unilateral ureteral obstruction (UUO) and an adenine diet (AD) to investigate whether SAMiRNA-AREG inhibited renal fibrosis. To investigate the delivery of SAMiRNA-AREG to the kidney, Cy5-labeled SAMiRNA-AREG was injected into UUO- and AD-induced renal fibrosis models. In both kidney disease models, SAMiRNA-AREG was delivered primarily to the damaged kidney. We also confirmed the protective effect of SAMiRNA-AREG in renal fibrosis models. SAMiRNA-AREG markedly decreased the UUO- and AD-induced AREG mRNA expression. Furthermore, the mRNA expression of fibrosis markers, including α-smooth muscle actin, fibronectin, α1(I) collagen, and α1(III) collagen in the UUO and AD-induced kidneys, was diminished in the SAMiRNA-AREG-treated mice. The transcription of inflammatory markers (tumor necrosis factor-α and monocyte chemoattractant protein-1) and adhesion markers (vascular cell adhesion molecule 1 and intercellular adhesion molecule 1) was attenuated. The hematoxylin and eosin, Masson's trichrome, and immunohistochemical staining results showed that SAMiRNA-AREG decreased renal fibrosis, AREG expression, and epidermal growth factor receptor (EGFR) phosphorylation in the UUO- and AD-induced models. Moreover, we studied the effects of SAMiRNA-AREG in response to TGF-β1 in mouse and human proximal tubule cells, and mouse fibroblasts. TGF-β1-induced extracellular matrix production and myofibroblast differentiation were attenuated by SAMiRNA-AREG. Finally, we confirmed that upregulated AREG in the UUO or AD models was mainly localized in the distal tubules. In conclusion, SAMiRNA-AREG represents a novel siRNA therapeutic for renal fibrosis by suppressing EGFR signals.

Expression of Amphiregulin in Enchondromas and Central Chondrosarcomas

OBJECTIVES

The aim of this study was to evaluate the role of amphiregulin protein, an epidermal growth factor receptor ligand, in cartilaginous tumors.

METHODS

Amphiregulin expression was examined in 31 enchondromas and 67 chondrosarcomas using immunohistochemistry analysis.

RESULTS

Overall, 15 enchondromas (48.40%) and 24 chondrosarcomas (35.82%) were positive for amphiregulin. According to the receiver operating characteristic curve test, no difference in amphiregulin expression was observed between enchondromas and low-grade chondrosarcomas (p=0.0880). Additionally, 39 lesions (16 in short bones, 13 in long bones, and 10 in flat bones) were positive for amphiregulin, exhibiting a higher percentage of positive cells (p=0.0030) and intensity of immunohistochemical expression (p=0.0055) in short bone lesions than in others. Among 25 enchondromas localized in short bones, 15 expressed amphiregulin; however, all 6 cases localized in long bones were negative for this marker (p=0.0177).

CONCLUSIONS

Amphiregulin did not help in distinguishing enchondromas from low-grade chondrosarcomas. The present study is the first to document the expression of this immunohistochemical marker in enchondromas. Furthermore, amphiregulin expression in enchondromas was localized in short bones, indicating a phenotypic distinction from that in long bones. This distinction may contribute to an improved understanding of the pathogenesis of these lesions.

Targeting amphiregulin (AREG) derived from senescent stromal cells diminishes cancer resistance and averts programmed cell death 1 ligand (PD-L1)-mediated immunosuppression

Aging is characterized by a progressive loss of physiological integrity, while cancer represents one of the primary pathological factors that severely threaten human lifespan and healthspan. In clinical oncology, drug resistance limits the efficacy of most anticancer treatments, and identification of major mechanisms remains a key to solve this challenging issue. Here, we highlight the multifaceted senescence-associated secretory phenotype (SASP), which comprises numerous soluble factors including amphiregulin (AREG). Production of AREG is triggered by DNA damage to stromal cells, which passively enter senescence in the tumor microenvironment (TME), a process that remarkably enhances cancer malignancy including acquired resistance mediated by EGFR. Furthermore, paracrine AREG induces programmed cell death 1 ligand (PD-L1) expression in recipient cancer cells and creates an immunosuppressive TME via immune checkpoint activation against cytotoxic lymphocytes. Targeting AREG not only minimized chemoresistance of cancer cells, but also restored immunocompetency when combined with classical chemotherapy in humanized animals. Our study underscores the potential of in vivo SASP in driving the TME-mediated drug resistance and shaping an immunosuppressive niche, and provides the proof of principle of targeting major SASP factors to improve therapeutic outcome in cancer medicine, the success of which can substantially reduce aging-related morbidity and mortality.

Valproic acid-induced amphiregulin secretion confers resistance to temozolomide treatment in human glioma cells

BACKGROUND

Glioblastoma multiforme (GBM) is the most severe type of primary brain tumor with a high mortality rate. Although extensive treatments for GBM, including resection, irradiation, chemotherapy and immunotherapy, have been tried, the prognosis is still poor. Temozolomide (TMZ), an alkylating agent, is a front-line chemotherapeutic drug for the clinical treatment of GBM; however, its effects are very limited because of the chemoresistance. Valproic acid (VPA), an antiepileptic agent with histone deacetylase inhibitor activity, has been shown to have synergistic effects with TMZ against GBM. The mechanism of action of VPA on TMZ combination therapy is still unclear. Accumulating evidence has shown that secreted proteins are responsible for the cross talking among cells in the tumor microenvironment, which may play a critical role in the regulation of drug responses.

METHODS

To understand the effect of VPA on secreted proteins in GBM cells, we first used the antibody array to analyze the cell culture supernatant from VPA-treated and untreated GBM cells. The results were further confirmed by lentivirus-mediated knockdown and exogenous recombinant administration.

RESULTS

Our results showed that amphiregulin (AR) was highly secreted in VPA-treated cells. Knockdown of AR can sensitize GBM cells to TMZ. Furthermore, pretreatment of exogenous recombinant AR significantly increased EGFR activation and conferred resistance to TMZ. To further verify the effect of AR on TMZ resistance, cells pre-treated with AR neutralizing antibody markedly increased sensitivity to TMZ. In addition, we also observed that the expression of AR was positively correlated with the resistance of TMZ in different GBM cell lines.

CONCLUSIONS

The present study aimed to identify the secreted proteins that contribute to the modulation of drug response. Understanding the full set of secreted proteins present in glial cells might help reveal potential therapeutic opportunities. The results indicated that AR may potentially serve as biomarker and therapeutic approach for chemotherapy regimens in GBM.

The endogenous hydrogen sulfide generating system regulates ovulation

The generation of free-radicals such as nitric oxide has been implicated in the regulation of ovarian function, including ovulation. Tissues that generate nitric oxide typically generate another free-radical gas, hydrogen sulfide (H₂S), although little is known about the role of H₂S in ovarian function. The hypothesis of this study was that H₂S regulates ovulation. Treatment with luteinizing hormone (LH) increased the levels of mRNA and protein of the H₂S generating enzyme cystathionine γ-lyase (CTH) in granulosa cells of mice and humans in vivo and in vitro. Pharmacological inhibition of H₂S generating enzymes reduced the number of follicles ovulating in mice in vivo and in vitro, and this inhibitory action was reversed by cotreatment with a H₂S donor. Addition of a H₂S donor to cultured mouse granulosa cells increased basal and LH-dependent abundance of mRNA encoding amphiregulin, betacellulin and tumor necrosis alpha induced protein 6, proteins important for cumulus expansion and follicle rupture. Inhibition of CTH activity reduced abundance of mRNA encoding matrix metalloproteinase-2 and -9 and tissue-type plasminogen activator, and cotreatment with the H₂S donor increased the levels of these mRNA above those stimulated by LH alone. We conclude that the H₂S generating system plays an important role in the propagation of the preovulatory cascade and rupture of the follicle at ovulation.

Cumulus cell pappalysin-1, luteinizing hormone/choriogonadotropin receptor, amphiregulin and hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 mRNA levels associate with oocyte developmental competence and embryo outcomes

PURPOSE

To determine whether a selected set of mRNA biomarkers expressed in individual cumulus granulosa cell (CC) masses show association with oocyte developmental competence, embryo ploidy status, and embryo outcomes.

METHODS

This prospective observational cohort pilot study assessed levels of mRNA biomarkers in 163 individual CC samples from 15 women stimulated in antagonist cycles. Nineteen mRNA biomarker levels were measured by real-time PCR and related to the development of their corresponding individually cultured oocytes and subsequent embryos, embryo ploidy status, and live birth outcomes.

RESULTS

PAPPA mRNA levels were significantly higher in CC from oocytes that led to euploid embryos resulting in live births and aneuploid embryos compared to immature oocytes by ANOVA. LHCGR mRNA levels were significantly higher in CC of oocytes resulting in embryos associated with live birth compared to immature oocytes and oocytes resulting in arrested embryos by ANOVA. Using a general linearized mixed model to assess ploidy status, CC HSD3B mRNA levels in oocytes producing euploid embryos were significantly lower than other oocyte outcomes, collectively. When transferred euploid embryos outcomes were analyzed by ANOVA, AREG mRNA levels were significantly lower and PAPPA mRNA levels significantly higher in CC from oocytes that produced live births compared to transferred embryos that did not form a pregnancy.

CONCLUSIONS

Collectively, PAPPA, LHCGR, and AREG mRNA levels in CC may be able to identify oocytes with the best odds of resulting in a live birth, and HSD3B1 mRNA levels may be able to identify oocytes capable of producing euploid embryos.

Transfer of Functional Cargo in Exomeres

Exomeres are a recently discovered type of extracellular nanoparticle with no known biological function. Herein, we describe a simple ultracentrifugation-based method for separation of exomeres from exosomes. Exomeres are enriched in Argonaute 1-3 and amyloid precursor protein. We identify distinct functions of exomeres mediated by two of their cargo, the β-galactoside α2,6-sialyltransferase 1 (ST6Gal-I) that α2,6- sialylates N-glycans, and the EGFR ligand, amphiregulin (AREG). Functional ST6Gal-I in exomeres can be transferred to cells, resulting in hypersialylation of recipient cell-surface proteins including β1-integrin. AREG-containing exomeres elicit prolonged EGFR and downstream signaling in recipient cells, modulate EGFR trafficking in normal intestinal organoids, and dramatically enhance the growth of colonic tumor organoids. This study provides a simplified method of exomere isolation and demonstrates that exomeres contain and can transfer functional cargo. These findings underscore the heterogeneity of nanoparticles and should accelerate advances in determining the composition and biological functions of exomeres.

CRB3 and the FERM protein EPB41L4B regulate proliferation of mammary epithelial cells through the release of amphiregulin

Numerous observations have suggested a connection between the maintenance of cell polarity and control of cell proliferation; however, the mechanisms underlying these connections remain poorly understood. Here we found that ectopic expression of CRB3, which was previously shown to restore tight junctions and membrane polarity in MCF-10A cells, induced a hyperproliferative phenotype, with significantly enlarged acini in basement membrane culture, similar to structures induced by expression of proliferative oncogenes such as cyclinD1. We found that CRB3-induced proliferation is epidermal growth factor (EGF)-independent and occurs through a mechanism that involves secretion of the EGF-family ligand, amphiregulin (AREG). The increase in AREG secretion is associated with an increase in the number and size of both early and late endosomes. Both the proliferative and endocytic phenotypes associated with CRB3 expression require the FERM-binding domain (FBD) but not the PDZ-binding domain of CRB3, arguing that this proliferative phenotype is independent of the PDZ-dependent polarity signaling by CRB3. We identified the FBD-containing protein, EPB41L4B, as an essential mediator of CRB3-driven proliferation and observed that the CRB3-dependent changes in endocytic trafficking were also dependent on EPB41L4B. Taken together, these data reveal a previously uncharacterized role for CRB3 in regulating proliferation in mammalian cells that is associated with changes in the endocytic trafficking machinery.

Loss of amphiregulin reduces myoepithelial cell coverage of mammary ducts and alters breast tumor growth

BACKGROUND

Amphiregulin (AREG), a ligand of the epidermal growth factor receptor, is not only essential for proper mammary ductal development, but also associated with breast cancer proliferation and growth. In the absence of AREG, mammary ductal growth is stunted and fails to expand. Furthermore, suppression of AREG expression in estrogen receptor-positive breast tumor cells inhibits in-vitro and in-vivo growth.

METHODS

We crossed AREG-null (AREG-/-) mice with the murine luminal B breast cancer model, MMTV-PyMT (PyMT), to generate spontaneous breast tumors that lack AREG (AREG-/- PyMT). We evaluated tumor growth, cytokeratin-8 (K8)-positive luminal cells, cytokeratin-14 (K14)-positive myoepithelial cells, and expression of AREG, Ki67, and PyMT. Primary myoepithelial cells from nontumor-bearing AREG+/+ mice underwent fluorescence-activated cell sorting and were adapted to culture for in-vitro coculture studies with AT-3 cells, a cell line derived from C57Bl/6 PyMT mammary tumors.

RESULTS

Intriguingly, PyMT-induced lesions progress more rapidly in AREG-/- mice than in AREG+/+ mice. Quantification of K8+ luminal and K14+ myoepithelial cells in non-PyMT AREG-/- mammary glands showed fewer K14+ cells and a thinner myoepithelial layer. Study of AT-3 cells indicated that coculture with myoepithelial cells or exposure to AREG, epidermal growth factor, or basic fibroblast growth factor can suppress PyMT expression. Late-stage AREG-/- PyMT tumors are significantly less solid in structure, with more areas of papillary and cystic growth. Papillary areas appear to be both less proliferative and less necrotic. In The Cancer Genome Atlas database, luminal-B invasive papillary carcinomas have lower AREG expression than luminal B invasive ductal carcinomas.

CONCLUSIONS

Our study has revealed a previously unknown role of AREG in myoepithelial cell development and PyMT expression. AREG expression is essential for proper myoepithelial coverage of mammary ducts. Both AREG and myoepithelial cells can suppress PyMT expression. We find that lower AREG expression is associated with invasive papillary breast cancer in both the MMTV-PyMT model and human breast cancer.

FOSL1 Promotes Kras-induced Lung Cancer through Amphiregulin and Cell Survival Gene Regulation

The FOSL1/AP-1 transcription factor regulates gene expression, thereby controlling various pathophysiological processes. It is a major effector of RAS-ERK1/2 signaling and is activated in human lung epithelia by tumorigenic stimuli. Recent evidence shows an inverse correlation between FOSL1 expression and the survival of patients with lung cancer and adenocarcinomas; however, its role in lung tumorigenesis remains elusive. In this work, we sought to determine the role of FOSL1 in Kras-induced lung adenocarcinoma in vivo and its downstream effector mechanisms. We used mice expressing the Kras oncogene in the lung with concomitant Fosl1 deletion, Kras-activated murine alveolar epithelial cells (mAECs) with Fosl1 deletion, and KRAS mutant human lung adenocarcinoma (HLAC) cells with FOSL1 deficiency, and performed cell proliferation and gene expression analyses. Mutant Kras induced Fosl1 expression in vitro (mAECs) and in vivo (lung tissue), and mice with Fosl1 deletion showed reduced levels of mutant Kras-induced lung tumorigenesis and survived longer than Fosl1-sufficient mice. Studies with mutant Kras-activated mAECs and KRAS-mutant HLAC cells revealed that FOSL1 regulates mutant KRAS-induced gene expression, thereby controlling cell proliferation and survival. In contrast, FOSL1 depletion in non-KRAS-mutant HLAC cells and nonmalignant human lung epithelia had no effect. Our data support the notion that FOSL1-mediated expression of amphiregulin and apoptotic and antioxidative genes plays a role in regulating HLAC cell proliferation and survival. FOSL1 is a determinant of lung cancer in vivo and regulates HLAC cell proliferation and survival, largely in the context of KRAS mutations. Activation of FOSL1 in adenocarcinomas may be a prognostic marker and potential target for human lung cancer with KRAS mutations.

Merlin, the product of NF2 gene, is associated with aromatase expression and estrogen formation in human liver tissues and liver cancer cells

The product of neurofibromatosis type 2 (NF2) gene, also known as Merlin/neurofibromin 2, homeostatically regulates liver stem cells by controlling abundance and signaling of epidermal growth factor receptor (EGFR), with a mechanism independent of the Hippo pathway. We have reported that locally elevated estrogen formation, driven by abnormally high expression and function of aromatase, may be implicated in development and progression of human hepatocellular carcinoma (HCC) through activation of a rapid signaling pathway mediated by amphiregulin (AREG) and EGFR. We have recently presented a model by which the aromatase-estrogen-amphiregulin-EGFR axis is activated in response to tissue injury and/or inflammatory disease, with its alteration eventually leading to development of major human tumors (liver, breast, prostate) and other chronic diseases (diabetes, obesity, Alzheimer's and heart disease). In this study, we investigated NF2 expression in liver cancer cells and tissues in relation to aromatase expression/function, estrogen receptor (ER) status and amphiregulin. Our data indicate that NF2 expression is associated with aromatase and AREG expression, being elevated in HCC tissues and HepG2 cells, intermediate in cirrhotic tissues and Huh7 cells, and lower in nontumoral liver and HA22T cells. In addition, NF2 expression is inversely related to wild type hERα66 and proportional to the expression of the membrane-associated hERα36 splice variant, as measured by exon-specific RT-PCR analysis, both in vivo and in vitro. Furthermore, incubation with estradiol induced a significant decrease of NF2 expression in both HA22T and Huh7 cells (over 54% and 22%, respectively), while no change could be observed in HepG2 cells, this effect being inversely related to aromatase expression and activity in HCC cell lines. Based on the above combined evidence, we hypothesize that NF2 behaves as a protein sensing tissue damage and aromatase-driven local estrogen formation, eventually leading to regulation of stem cells differentiation and tissue repair.

Coordinated Regulation Among Progesterone, Prostaglandins, and EGF-Like Factors in Human Ovulatory Follicles

CONTEXT

In animal models, the luteinizing hormone surge increases progesterone (P4) and progesterone receptor (PGR), prostaglandins (PTGs), and epidermal growth factor (EGF)-like factors that play essential roles in ovulation. However, little is known about the expression, regulation, and function of these key ovulatory mediators in humans.

OBJECTIVE

To determine when and how these key ovulatory mediators are induced after the luteinizing hormone surge in human ovaries.

DESIGN AND PARTICIPANTS

Timed periovulatory follicles were obtained from cycling women. Granulosa/lutein cells were collected from in vitro fertilization patients.

MAIN OUTCOME MEASURES

The in vivo and in vitro expression of PGR, PTG synthases and transporters, and EGF-like factors were examined at the level of messenger RNA and protein. PGR binding to specific genes was assessed. P4 and PTGs in conditioned media were measured.

RESULTS

PGR, PTGS2, and AREG expressions dramatically increased in ovulatory follicles at 12 to 18 hours after human chorionic gonadotropin (hCG). In human granulosa/lutein cell cultures, hCG increased P4 and PTG production and the expression of PGR, specific PTG synthases and transporters, and EGF-like factors, mimicking in vivo expression patterns. Inhibitors for P4/PGR and EGF-signaling pathways reduced hCG-induced increases in PTG production and the expression of EGF-like factors. PGR bound to the PTGS2, PTGES, and SLCO2A1 genes.

CONCLUSIONS

This report demonstrated the time-dependent induction of PGR, AREG, and PTGS2 in human periovulatory follicles. In vitro studies indicated that collaborative actions of P4/PGR and EGF signaling are required for hCG-induced increases in PTG production and potentiation of EGF signaling in human periovulatory granulosa cells.

Amphiregulin triggered epidermal growth factor receptor activation confers in vivo crizotinib-resistance of EML4-ALK lung cancer and circumvention by epidermal growth factor receptor inhibitors

Crizotinib, a first-generation anaplastic lymphoma kinase (ALK) tyrosine-kinase inhibitor, is known to be effective against echinoderm microtubule-associated protein-like 4 (EML4)-ALK-positive non-small cell lung cancers. Nonetheless, the tumors subsequently become resistant to crizotinib and recur in almost every case. The mechanism of the acquired resistance needs to be deciphered. In this study, we established crizotinib-resistant cells (A925LPE3-CR) via long-term administration of crizotinib to a mouse model of pleural carcinomatous effusions; this model involved implantation of the A925LPE3 cell line, which harbors the EML4-ALK gene rearrangement. The resistant cells did not have the secondary ALK mutations frequently occurring in crizotinib-resistant cells, and these cells were cross-resistant to alectinib and ceritinib as well. In cell clone #2, which is one of the clones of A925LPE3-CR, crizotinib sensitivity was restored via the inhibition of epidermal growth factor receptor (EGFR) by means of an EGFR tyrosine-kinase inhibitor (erlotinib) or an anti-EGFR antibody (cetuximab) in vitro and in the murine xenograft model. Cell clone #2 did not have an EGFR mutation, but the expression of amphiregulin (AREG), one of EGFR ligands, was significantly increased. A knockdown of AREG with small interfering RNAs restored the sensitivity to crizotinib. These data suggest that overexpression of EGFR ligands such as AREG can cause resistance to crizotinib, and that inhibition of EGFR signaling may be a promising strategy to overcome crizotinib resistance in EML4-ALK lung cancer.

Abnormal amphiregulin expression correlates with gastric cancer prognosis

Gastric cancer (GC) is a global health issue with a high mortality rate. Early diagnosis and tracking of GC is a challenge due to a lack of reliable tools. Amphiregulin (AREG) is a member of the epidermal growth factor (EGF) family that activates growth signaling upon binding of EGF receptors. Elevated AREG expression is associated with various pathological conditions, including cancer. Here, we investigated whether increased AREG expression is a disease indicator and/or prognostic biomarker for GC. We used tissue microarray and quantitative real-time polymerase chain reaction to assess AREG expression in clinical tissue specimens at various stages of GC and a conducted bioinformatics analysis to evaluate the value of AREG over-expression as a GC biomarker. We found that both mRNA and protein expression of AREG were increased in the tissues of GC patients when compared to tissues from non-cancer patients or normal tissues. High expression of AREG was also associated with GC clinicopathological characteristics and poor survival. Thus, over-expression of AREG could serve as a novel GC biomarker, and active surveillance of its expression could be a novel approach to GC diagnosis and monitoring.

Impact of tumour RAS/BRAF status in a first-line study of panitumumab + FOLFIRI in patients with metastatic colorectal cancer

BACKGROUND

To investigate tumour biomarker status and efficacy of first-line panitumumab+FOLFIRI for metastatic colorectal carcinoma (mCRC).

METHODS

154 patients received first-line panitumumab + FOLFIRI every 14 days. Primary end point was objective response rate (ORR). Data were analysed by tumour RAS (KRAS/NRAS) and BRAF status, and baseline amphiregulin (AREG) expression.

RESULTS

Objective responses occurred more frequently in RAS wild type (WT) (59%) vs RAS mutant (MT) (41%) mCRC and in RAS WT/BRAF WT (68%) vs RAS or BRAF MT (37%) disease. Median response duration was longer in RAS WT (13.0 months) vs RAS MT (5.8 months) (hazard ratio (HR): 0.16). Median progression-free survival was longer in RAS WT vs MT (11.2 vs 7.3 months; HR, 0.37) and was also longer in RAS WT/BRAF WT vs RAS or BRAF MT (13.2 vs 6.9 months; HR, 0.25). Incidence of adverse events was similar regardless of RAS/BRAF status, and no new safety signals were noted. Among patients with RAS WT tumours, ORR was 67% with high AREG expression and 38% with low AREG expression.

CONCLUSIONS

First-line panitumumab+FOLFIRI was associated with favourable efficacy in patients with RAS WT and RAS WT/BRAF WT vs MT mCRC tumours and was well tolerated.

Amphiregulin enhances VEGF-A production in human chondrosarcoma cells and promotes angiogenesis by inhibiting miR-206 via FAK/c-Src/PKCδ pathway

Chondrosarcoma is the second most common primary malignancy of bone after myeloma and osteosarcoma. Chondrosarcoma development may be linked to angiogenesis, which is principally elicited by vascular endothelial growth factor-A (VEGF-A). The expression of VEGF-A has been recognized as a prognostic marker in angiogenesis. Amphiregulin (AR), an epidermal growth factor receptor ligand, promotes tumor proliferation, metastasis and angiogenesis. However, the role of AR in VEGF-A expression and angiogenesis in human chondrosarcoma remains largely unknown. This current study shows that AR promoted VEGF-A production and induced angiogenesis of human endothelial progenitor cells. Moreover, AR-enhanced VEGF-A expression and angiogenesis involved the FAK, c-Src and PKCδ signaling pathways, while miR-206 expression was negatively mediated by AR via the FAK, c-Src and PKCδ pathways. Our results illustrate the clinical significance between AR, VEGF-A and miR-206, as well as tumor stage, in human chondrosarcoma. AR may represent a novel therapeutic target in the metastasis and angiogenesis of chondrosarcoma.

Progesterone-Based Therapy Protects Against Influenza by Promoting Lung Repair and Recovery in Females

Over 100 million women use progesterone therapies worldwide. Despite having immunomodulatory and repair properties, their effects on the outcome of viral diseases outside of the reproductive tract have not been evaluated. Administration of exogenous progesterone (at concentrations that mimic the luteal phase) to progesterone-depleted adult female mice conferred protection from both lethal and sublethal influenza A virus (IAV) infection. Progesterone treatment altered the inflammatory environment of the lungs, but had no effects on viral load. Progesterone treatment promoted faster recovery by increasing TGF-β, IL-6, IL-22, numbers of regulatory Th17 cells expressing CD39, and cellular proliferation, reducing protein leakage into the airway, improving pulmonary function, and upregulating the epidermal growth factor amphiregulin (AREG) in the lungs. Administration of rAREG to progesterone-depleted females promoted pulmonary repair and improved the outcome of IAV infection. Progesterone-treatment of AREG-deficient females could not restore protection, indicating that progesterone-mediated induction of AREG caused repair in the lungs and accelerated recovery from IAV infection. Repair and production of AREG by damaged respiratory epithelial cell cultures in vitro was increased by progesterone. Our results illustrate that progesterone is a critical host factor mediating production of AREG by epithelial cells and pulmonary tissue repair following infection, which has important implications for women's health.

RYR2, PTDSS1 and AREG genes are implicated in a Lebanese population-based study of copy number variation in autism

Autism Spectrum Disorders (ASDs) are a group of neurodevelopmental disorders characterized by ritualistic-repetitive behaviors and impaired verbal and non-verbal communication. Objectives were to determine the contribution of genetic variation to ASDs in the Lebanese. Affymetrix Cytogenetics Whole-Genome 2.7 M and CytoScan(™) HD Arrays were used to detect CNVs in 41 Lebanese autistic children and 35 non-autistic, developmentally delayed and intellectually disabled patients. 33 normal participants were used as controls. 16 de novo CNVs and 57 inherited CNVs, including recognized pathogenic 16p11.2 duplications and 2p16.3 deletions were identified. A duplication at 1q43 classified as likely pathogenic encompasses RYR2 as a potential ASD candidate gene. This previously identified CNV has been classified as both pathogenic, and, of uncertain significance. A duplication of unknown significance at 10q11.22, proposed as a modulator for phenotypic disease expression in Rett syndrome, was also identified. The novel potential autism susceptibility genes PTDSS1 and AREG were uncovered and warrant further genetic and functional analyses. Previously described and novel genetic targets in ASD were identified in Lebanese families with autism. These findings may lead to improved diagnosis of ASDs and informed genetic counseling, and may also lead to untapped therapeutic targets applicable to Lebanese and non-Lebanese patients.

A Distinct Function of Regulatory T Cells in Tissue Protection

Regulatory T (Treg) cells suppress immune responses to a broad range of non-microbial and microbial antigens and indirectly limit immune inflammation-inflicted tissue damage by employing multiple mechanisms of suppression. Here, we demonstrate that selective Treg cell deficiency in amphiregulin leads to severe acute lung damage and decreased blood oxygen concentration during influenza virus infection without any measureable alterations in Treg cell suppressor function, antiviral immune responses, or viral load. This tissue repair modality is mobilized in Treg cells in response to inflammatory mediator IL-18 or alarmin IL-33, but not by TCR signaling that is required for suppressor function. These results suggest that, during infectious lung injury, Treg cells have a major direct and non-redundant role in tissue repair and maintenance-distinct from their role in suppression of immune responses and inflammation-and that these two essential Treg cell functions are invoked by separable cues.

Hypothermia and rewarming induce gene expression and multiplication of cells in healthy rat prostate tissue

Prostate cancer has been extensively studied, but cellular stress responses in healthy prostate tissue are rarely investigated. Hypothermia is known to cause alterations in mRNA and protein expressions and stability. The aim of this study was to use normal rat prostate as a model in order to find out consequences of cold exposure and rewarming on the expressions of genes which are either members or functionally/structurally related to erythroblastic leukemia viral oncogene B (ErbB) signaling pathway. Relative mRNA expressions of amphiregulin (AMR), cyclin D1 (CyD1), cyclin-dependent kinase inhibitor 1A (p21), transmembrane form of the prostatic acid phosphatase (PAcP), thrombomodulin (TM) and heat shock transcription factor 1 (HSF1) in rat ventral prostate were quantified in mild (2 or 4.5 h at room temperature) and severe (2 or 4.5 h at +10°C) hypothermia and in rewarming after cold exposure (2 h at +10°C followed by 2 h at room temperature or 3 h at +28°C). AMR protein level, apoptotic Bcl-2 associated X protein to B-cell CLL/lymphoma 2 (Bax/Bcl-2) mRNA ratio and proliferative index Ki-67 were determined. 4.5-h mild hypothermia, 2-h severe hypothermia and rewarming increased expression of all these genes. Elevated proliferation index Ki-67 could be seen in 2-h severe hypothermia, and the proliferation index had its highest value in longer rewarming with totally recovered normal body temperature. Pro-apoptotic tendency could be seen in 2-h mild hypothermia while anti-apoptosis was predominant in 4.5-h mild hypothermia and in shorter rewarming with only partly recovered body temperature. Hypothermia and following rewarming promote the proliferation of cells in healthy rat prostate tissue possibly via ErbB signaling pathway.