Epidermal growth factor stimulates proliferation of mouse uterine epithelial cells in primary culture

Liver X receptor agonists exert antitumor effects against hepatocellular carcinoma via inducing REPS2 expression

Recent studies show that liver X receptor (LXR) agonists exert significant antitumor effects in a variety of tumor cell lines including hepatocellular carcinoma (HCC). But the molecular mechanisms underlying LXR antitumor activity are not fully understood. In this study we investigated the effect of LXR agonist T0901317 (T317) on HCC development and its relationship with RalA binding protein 1 (RALBP1)-associated EPS domain containing 2 (REPS2)/epidermal growth factor receptor (EGFR) signaling axis. We showed that T317 (0.1-0.5 μM) dose-dependently increased REPS2 expression in normal hepatocytes (BNLCL.2 and LO2) and HCC cells (HepG2 and Huh-7). Using promoter activity assay and chromatin immunoprecipitation (CHIP) assay we demonstrated that T317 enhanced REPS2 expression at the transcriptional level via promoting the binding of LXR protein to the LXR-response element (LXRE) in the REPS2 promoter region. We showed that the inhibitory effect of T317 on the proliferation and migration of HCC cells was closely related to REPS2. Moreover, we revealed that T317 (400 nM) increased expression of REPS2 in HepG2 cells, thus inhibiting epidermal growth factor (EGF)-mediated endocytosis of EGFR as well as the downstream activation of AKT/NF-κB, p38MAPK, and ERK1/2 signaling pathways. Clinical data analysis revealed that REPS2 expression levels were inversely correlated with the development of HCC and reduced REPS2 expression associated with poor prognosis, suggesting that REPS2 might be involved in the development of HCC. In conclusion, this study provides new insights into the potential mechanisms of LXR agonist-inhibited HCC.

Continuous artificial light potentially disrupts central and peripheral reproductive clocks leading to altered uterine physiology and reduced pregnancy success in albino mice

AIMS

The mechanism behind clock coordination in female reproductive disorders is poorly understood despite the known importance of coordinated and synchronized timing of central and clocks in reproductive organs. We investigated the effect of continuous artificial light (LL) on the central and peripheral reproductive clock gene (Bmal1, Clock, Per1, Per2 and Cry1) and its downstream regulators (Hgf, PR-A and HOXA10) during non-pregnancy and pregnancy phases of female mice.

MAIN METHODS

Mice (n = 60) in two sets, were maintained under continuous light (LL) and natural day cycle (LD;12L: 12D) for both non-pregnant and pregnant study. Tissues from hypothalamus-containing SCN, ovary, uterus and serum were collected at different zeitgeber time points (ZT; at 4-h intervals across 24-h periods).

KEY FINDINGS

LL exposure desynchronized the expressions of the clock mRNAs (Bmal1, Clock, Per1, Per2 and Cry1) in SCN, ovary, and uterus along with Hgf mRNA rhythm. LL significantly increased the thickness of endometrial tissues. Furthermore, the pregnant study revealed lower serum progesterone level during peri- and post-implantation under LL along with downregulated expression of progesterone receptor (PR) as well as progesterone dependent uterine Homeobox A-10 (Hoxa10) proteins with lowered pregnancy outcomes.

SIGNIFICANCE

Our result suggests that LL disrupted the circadian coordination between central and clock genes in reproductive tissue leading to interrupted uterine physiology and altered pregnancy in mice. This led us to propose that duration of light exposure at work-places or home for females is very important in prevention of pregnancy anomalies.

The EGFR-P38 MAPK axis up-regulates PD-L1 through miR-675-5p and down-regulates HLA-ABC via hexokinase-2 in hepatocellular carcinoma cells

BACKGROUND

Immunotherapy has been shown to be a promising strategy against human cancers. A better understanding of the immune regulation in hepatocellular carcinoma (HCC) could help the development of immunotherapy against HCC. The epidermal growth factor receptor (EGFR) signaling is frequently activated in HCC and plays important roles in tumorigenesis. However, its role in HCC immunity is still largely unknown. This study aimed to investigate the impact of EGFR signaling on programmed death-ligand 1 (PD-L1) and human leukocyte antigen class-I (HLA-I) expression in HCC cells and its underlying mechanisms.

METHODS

The expression of phosphorylated EGFR (p-EGFR), PD-L1, and HLA-I (HLA-ABC) in HCC specimens was detected by immunohistochemistry, and their correlations were analyzed. PD-L1 and HLA-ABC expression in EGFR-activated HCC cells were detected by quantitative real-time PCR, Western blotting, and flow cytometry, and T cell-mediated lysis was performed to test the immunosuppressive effects of PD-L1 and HLA-ABC alterations in HCC cells. Furthermore, the underlying mechanisms of EGFR activation-induced PD-L1 up-regulation and HLA-ABC down-regulation were explored by animal experiments, luciferase reporter assay, and gene gain- and loss-of-function studies.

RESULTS

p-EGFR was positively correlated with PD-L1 and negatively correlated with HLA-ABC expression in HCCs. EGFR activation by its ligand EGF up-regulated PD-L1 and down-regulated HLA-ABC in HCC cells, which was functionally important and could be abolished by the EGFR inhibitor, gefitinib, both in vitro and in vivo. Mechanistically, enhanced P38 mitogen-activated protein kinase (MAPK) activation down-regulated microRNA-675-5p (miR-675-5p) and up-regulated glycolysis-related enzyme hexokinase 2 (HK2); miR-675-5p down-regulation enhanced the stability of PD-L1 mRNA probably via the 3'-untranslated region (3'-UTR) of PD-L1 and thereby caused PD-L1 accumulation, and HK2 up-regulation enhanced aerobic glycolysis and mediated a decrease in HLA-ABC.

CONCLUSIONS

The EGFR-P38 MAPK axis could up-regulate PD-L1 through miR-675-5p and down-regulate HLA-ABC via HK2 in HCC cells. Our study reveals a novel signaling network that may cause immune suppression in HCC and suggests that EGFR signaling can be targeted for HCC immunotherapy.

The uterine-chemokine-brain axis: menstrual cycle-associated symptoms (MCAS) are in part mediated by CCL2, CCL5, CCL11, CXCL8 and CXCL10

OBJECTIVE

To examine associations between chemokines and menstrual cycle associated symptoms (MCAS).

METHODS

Forty-one women completed the Daily Record of Severity of Problems (DRSP) rating scale during 28 consecutive days of the menstrual cycle. MCAS is diagnosed when the total daily DRSP score during the menstrual cycle is > 0.666 percentile. We assayed plasma CCL2, CCL5, CCL11, CXCL8, CXCL10, EGF, IGF-1, and PAI-1 at days 7, 14, 21 and 28 of the menstrual cycle.

RESULTS

CCL2, CCL5, CCL11 and EGF are significantly higher in women with MCAS than in those without. Increased CCL2, CXCL10, CXCL8, CCL11 and CCL5 levels are significantly associated with DRSP scores while CCL2 is the most significant predictor explaining 39.6% of the variance. The sum of the neurotoxic chemokines CCL2, CCL11 and CCL5 is significantly associated with the DRSP score and depression, physiosomatic, breast-craving and anxiety symptoms. The impact of chemokines on MCAS symptoms differ between consecutive weeks of the menstrual cycle with CCL2 being the most important predictor of increased DRSP levels during the first two weeks, and CXCL10 or a combination of CCL2, CCL11 and CCL5 being the best predictors during week 3 and 4, respectively.

DISCUSSION

The novel case definition "MCAS" is externally validated by increased levels of uterus-associated chemokines and EGF. Those chemokines are involved in MCAS and are regulated by sex hormones and modulate endometrium functions and brain neuro-immune responses, which may underpin MCAS symptoms. As such, uterine-related chemokines may link the uterus with brain functions via a putative uterine-chemokine-brain axis.

No Association between EGF +61 A/G Polymorphism and Increased Risk of Glioma

A single nucleotide polymorphism (SNP) of the epidermal growth factor ( EGF) gene +61 A/G in the 5′-untranslated region has been reported to be associated with susceptibility to glioma. A case-control study (168 glioma patients and 194 normal controls) was conducted to elucidate its possible association with the risk of glioma in the Chinese population. Polymerase chain reaction-restriction fragment length polymorphism assay was used to analyze the EGF genotypes. The genotyping results were further confirmed by direct sequencing. The EGF +61A and +61G allele frequencies in the glioma group were 32.1% and 67.9%, respectively, while they were 30.4% and 69.6% in the healthy controls. Furthermore, the frequency of the A/A, A/G and G/G genotypes in glioma patients was 8.9%, 46.4%, and 44.7%, respectively, and 8.3%, 44.3%, and 47.4% in controls. There was no significant difference between patients and healthy controls. The EGF +61 A/G and +61 G/G genotypes were not significantly associated with risk of glioma compared with the A/A genotype. In addition, no significant association was observed between EGF polymorphism and different histological grades of glioma. These results indicate that the EGF +61 A/G polymorphism is not associated with susceptibility to glioma in the Chinese population. In addition, a literature review revealed a significantly higher rate of the A/A genotype in Caucasian compared with East Asian subjects. Such differences in genotype distribution between Caucasian and Asian people should be taken into account in future studies.

Growth factor induced proliferation, migration, and lumen formation of rat endometrial epithelial cells in vitro

Endometrial modulation is essential for the preservation of normal uterine physiology, and this modulation is driven by a number of growth factors. The present study investigated the mitogenic, motogenic, and morphogenic effects of epidermal growth factor (EGF) and hepatocyte growth factor (HGF) on rat endometrial epithelial (REE) cells. The REE cells were isolated and cultured and then characterized based on their morphology and their expression of epithelial cell markers. The MTT assay revealed that EGF and HGF induce proliferation of REE cells. Consistent with increased proliferation, we found that the cell cycle regulatory factor Cyclin D1 was also upregulated upon EGF and HGF addition. REE cell migration was prompted by EGF, as observed with the Oris Cell Migration Assay. The morphogenic impact of growth factors on REE cells was studied in a three-dimensional BD Matrigel cell culture system, wherein these growth factors also increased the frequency of lumen formation. In summary, we show that EGF and HGF have a stimulatory effect on REE cells, promoting proliferation, cell migration, and lumen formation. Our findings provide important insights that further the understanding of endometrial regeneration and its regulation.

Runx3 expression and its roles in mouse endometrial cells

Runx3 is a transcription factor that belongs to the Runx family. We studied the localization of Runx3 mRNA in the mouse uterus, and its function in the mouse endometrium using Runx3 knockout (Runx3(-/-)) mice. Runx3 mRNA was detected in the endometrial luminal epithelial cells, glandular epithelial cells and stromal cells below the epithelial cell layer on the luminal side. The uteri of Runx3(-/-) mice were smaller than those of wt mice. The endometrial layer and uterine glands of Runx3(-/-) mice were less developed than those of wild-type mice, and the endometrial stromal layer was thinner. Transforming growth factor β1 and β3 (TGFβ1 and β3) mRNA levels in endometrial stromal cells of Runx3(-/-) mice were low compared with those of wild-type mice. Estradiol-17β (E2) increased Tgfb2 mRNA levels in endometrial stromal cells of Runx3(-/-) mice, but not in those of wild-type mice. E2 increased epidermal growth factor (EGF) mRNA levels in endometrial stromal cells of wild-type mice, but did not increase those of Runx3(-/-) mice. The diminished Tgfb1 and Tgfb3 mRNA expressions may lead to the reduced proliferation of endometrial stromal cells. Alterations of E2-associated expressions of Tgfb2 and Egf mRNA in endometrial stromal cells of Runx3(-/-) mice may be associated with suppression of E2-dependent endometrial epithelial cell proliferation in Runx3(-/-) mice. Thus, Runx3 is likely to be a regulatory factor responsible for endometrial growth.

Expression of the erbB/HER receptor family in the bovine uterus during the sexual cycle and the relation of this family to serum sex steroids

Our study was designed to investigate immunohistochemically the expression of the receptors of the erbB/HER family (erbB1/HER1, erbB2/HER2, erbB3/HER3, erbB4/HER4) in the bovine uterus during the follicular and luteal phases of the sexual cycle, and the relation to ovarian sex steroids. The stage of the estrous cycle in 30 Holstein bovine was assessed based on the gross and histological appearance of the ovaries and uterus, and on blood steroid hormone levels. Tissue samples taken from the uterus were fixed in 10% formaldehyde for routine histological processing. Positive membrane and cytoplasmic staining of varying intensity were determined in the uterus during the follicular and luteal phases of the sexual cycle for erbB/HER receptors in luminal and glandular epithelial cells, connective tissue, smooth muscle and vascular endothelial and smooth muscle cells. We demonstrated that the apical and basal membranes of luminal epithelial cells and the apical membrane of glandular epithelial cells reacted with erbB1/HER1 and erbB2/HER2 during both the follicular and luteal phases. The reaction for erbB3/HER3 and erbB4/HER4 was stronger in the cytoplasm of luminal and glandular epithelial cells, but was heterogeneous. During both the follicular and luteal phases, the percentage and staining intensity of luminal and superficial glandular epithelial cells reacting positively with the receptors erbB1/HER1, erbB2/HER2, erbB3/HER3 and erbB4/HER4 were greater than those of deep glandular epithelial and connective tissue cells (p < 0.05). We demonstrated that the expression of the erbB/HER receptor family varied with different cell types in the bovine uterus during the follicular and luteal phases.

Association between epidermal growth factor 61A/G polymorphism and hepatocellular carcinoma susceptibility in Chinese patients

BACKGROUND AND AIMS

Chronic hepatitis B virus (HBV) infection is an important risk factor for hepatocellular carcinoma (HCC) development in China, while little is known of the genetic susceptibility to hepatocarcinogenesis. The epidermal growth factor (EGF) pathway plays an important role in tumorigenesis, including HCC. EGF polymorphisms are associated with susceptibility to several types of cancers. Therefore, this study aimed to assess whether EGF genetic polymorphisms can influence HCC development.

METHODS

A total of 338 chronic HBV-infected patients (186 HCC patients and 152 cirrhotic patients) and 186 healthy individuals were enrolled in this study. EGF 61A/G polymorphisms of all subjects and 12 cell lines were assayed with polymerase chain reaction-restriction fragment length polymorphism and the sequencing method. Furthermore, EGF protein levels were measured in the serum and the results were compared with the different genotypes. EGF expression in the liver tissue of the HCC patients was detected by immunohistochemical analysis.

RESULTS

EGF 61A and 61G allele frequencies in healthy subjects were 28.76 and 71.24%. EGF 61GG and G allele frequencies in the HCC group were higher than those in the cirrhosis group. EGF protein levels with the GG genotype were significantly higher than those with either the GA or the AA genotype. About 59.09% of HCC liver tumour tissues assayed showed EGF protein expression.

CONCLUSIONS

The EGF 61 GG genotype might be associated with a high risk for the development of chronic HBV infection-related HCC in Chinese patients.

Insulin-Like Growth Factor-I Stimulated DNA Replication in Mouse Endometrial Stromal Cells

Much evidence has suggested that sex steroid hormone-induced growth of uterine cells is mediated by polypeptide growth factors synthesized in uterine tissues. The present study aimed to clarify the effect of insulin-like growth factor-I (IGF-I) on the proliferation of mouse endometrial stromal cells obtained from immature mice. IGF-I and IGF-I receptor (type I) mRNAs were detected in the endometrial stromal cells. IGF-I increased bromodeoxyuridine (BrdU) uptake in the endometrial stromal cells, indicating an increase in DNA replication. E2 increased IGF-I mRNA levels in the endometrial stromal cells. IGF-I receptor is a tyrosine kinase receptor, and treatment with genistein, a tyrosine kinase inhibitor, reduced IGF-I-induced BrdU-uptake in the endometrial stromal cells. IGF-I signaling pathways involve mitogen-activated protein (MAP) kinase and phosphatidylinositol-3 kinase (PI-3 kinase). Treatment with 10(-7) M of the MAP kinase inhibitor PD098059 and 10(-5) M of the PI-3 kinase inhibitor LY294002 decreased IGF-I-induced BrdU-uptake in the endometrial stromal cells. However, LY294002 (10(-5) M) also decreased the BrdU-uptake in the absence of IGF-I treatment. These results suggest that endometrial IGF-I is involved in the proliferation of endometrial stromal cells in a paracrine or autocrine manner, and that the MAP kinase pathway is involved in DNA replication of endometrial stromal cells.