Artesunate-induced ATG5-related autophagy enhances the cytotoxicity of NK92 cells on endometrial cancer cells via interactions between CD155 and CD226/TIGIT.

Uterine corpus endometrial carcinoma (UCEC) is the most prevalent gynecologic cancer in developed countries and lacks efficient therapeutic strategies. Artesunate (ART), a well-modified derivate of artemisinin, exerts potent anti-cancer effects apart from its classical anti-malaria feature. Autophagy is a universal double-edged process in cell survival, and CD155 is a novel immune checkpoint highly expressed in numerous cancers. However, the relationships among ART, autophagy, and CD155 remain unclear in UCEC. In this study, we discovered that ART not only inhibited proliferation and migration, promoted apoptosis, but also induced autophagy in UCEC cells. Meanwhile, ART-induced autophagy elevated the level of CD155 in UCEC cells, thereby enhancing the cytotoxicity of natural killer cell line (NK92) by modulating the interactions between CD155 and its receptors in NK92 cells via upregulation of co-stimulator CD226 and downregulation of co-inhibitor TIGIT. Additionally, ART regulated CD155 partially via ATG5, and knockdown of ATG5 dampened the expression of CD155 in UCEC cells, thus decreasing the cytotoxicity of NK92 cells. Therefore, this study demonstrated the dual anti-cancer effects of ART as it could induce cell-killing directly and indirectly, which provides novel insights into the anti-cancer mechanisms of ART on UCEC.

Preoperative CD4+CD25+/CD4+ and tumor diameter predict prognosis in male patients with bladder cancer.

Aim: The value of the peripheral blood lymphocyte subpopulation ratios and tumor diameter for prognosis in bladder cancer (BC) patients needs to be explored. Materials & methods: A total of 161 male BC patients and 68 male normal controls were retrospectively reviewed. The value of combining predictor consisted of both CD4+CD25+/CD4+ and computed tomography urography tumor diameter (CTU-D) on stage, overall survival (OS) and recurrence probability was analyzed by logistic regression, Kaplan-Meier method and log-rank test. Results: The combining predictor was a statistically independent risk for stage; dramatic differences in OS and recurrence probability were found between the combining predictor-high (cut-off point >0.08) and combining predictor-low groups (cut-off point ≤0.08). Conclusion: The combining predictor could be a significant predictor for advanced stage, OS and recurrence probability in male patients with BC.

Estrogen inhibits autophagy and promotes growth of endometrial cancer by promoting glutamine metabolism.

BACKGROUND: Excessive estrogen exposure is an important pathogenic factor in uterine endometrial cancer (UEC). Recent studies have reported the metabolic properties can influence the progression of UEC. However, the underlying mechanisms have not been fully elucidated. METHODS: Glutaminase (GLS), MYC and autophagy levels were detected. The biological functions of estrogen-MYC-GLS in UEC cells (UECC) were investigated both in vivo and in vitro. RESULTS: Our study showed that estrogen remarkably increased GLS level through up-regulating c-Myc, and enhanced glutamine (Gln) metabolism in estrogen-sensitive UEC cell (UECC), whereas fulvestrant (an ER inhibitor antagonist) could reverse these effects. Estrogen remarkably promoted cell viability and inhibited autophagy of estrogen sensitive UECC. However, CB-839, a potent selective oral bioavailable inhibitor of both splice variants of GLS, negatively regulated Gln metabolism, and inhibited the effects of Gln and estrogen on UECC's growth and autophagy in vitro and / or in vivo. CONCLUSIONS: CB-839 triggers autophagy and restricts growth of UEC by suppressing ER/Gln metabolism, which provides new insights into the potential value of CB-839 in clinical treatment of estrogen-related UEC.

Decidual stromal cells promote the differentiation of CD56bright CD16- NK cells by secreting IL-24 in early pregnancy.

PROBLEM: Decidual stromal cells (DSCs) are important origins of cytokines to modulate maternal-fetal immunotolerance and provide a feasible environment for embryo implantation and development. Interleukin (IL)-24 is a multifunctional cancer killing cytokine and a pleiotropic immunoregulator with complex potency according to tissue or cell types. Its role in establishment and maintenance of normal pregnancy is largely unknown. The aim of our study was to investigate the function and significance of IL-24 and its receptor in the coordination between DSCs and natural killer cells (NK) in early pregnancy. METHOD OF STUDY: The levels of IL-24 in DSC, endometrial stromal cell (ESC), peripheral blood NK cells (pNK), or decidual NK cells (dNK) culture supernatants were detected by enzyme-linked immunosorbent assay (ELISA), and the levels of IL-24 receptors were determined by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry assays. The effect of IL-24 on the functions of decidual NK cells was analyzed by flow cytometry assays in vitro. RESULTS: The concentration of IL-24 in culture supernatant of DSCs was significantly higher than that of ESCs. Both eNK (endometrial NK cells) and dNK highly expressed IL-24 receptors (IL-20R1 and IL-22R1), especially on CD56dim eNK. However, there were extremely low levels of IL-20R1 and IL-22R1 on pNK. Recombinant human IL-24 or DSCs-secreted IL-24 downregulated the levels of CD16, Granzyme B, perforin, and interferon (IFN)-γ and upregulated the levels of inhibitory receptors killer-cell immunoglobulin-like receptor (KIR)2DL1 and KIR3DL1, or immunotolerant or angiogenic cytokines (eg, transforming growth factor (TGF)-ß, IL-10, and IL-8), and elevated the percentage of CD56bright CD16- dNK in vitro. CONCLUSION: These data suggest that DSCs promote the differentiation of CD56bright CD16- NK with high levels of inhibitory receptors, immunotolerant, and angiogenic cytokines by secreting IL-24 during decidualization in early pregnancy.

Melatonin restricts the viability and angiogenesis of vascular endothelial cells by suppressing HIF-1α/ROS/VEGF.

Angiogenesis is an essential process involved in various physiological, including placentation, and pathological, including cancer and endometriosis, processes. Melatonin (MLT), a well­known natural hormone secreted primarily in the pineal gland, is involved in regulating neoangiogenesis and inhibiting the development of a variety of cancer types, including lung and breast cancer. However, the specific mechanism of its anti­angiogenesis activity has not been systematically elucidated. In the present study, the effect of MLT on viability and angiogenesis of human umbilical vein endothelial cells (HUVECs), and the production of vascular endothelial growth factor (VEGF) and reactive oxygen species (ROS), under normoxia or hypoxia was analyzed using Cell Counting kit 8, tube formation, flow cytometry, ELISA and western blot assays. It was determined that the secretion of VEGF by HUVECs was significantly increased under hypoxia, while MLT selectively obstructed VEGF release as well as the production of ROS under hypoxia. Furthermore, MLT inhibited the viability of HUVECs in a dose­dependent manner and reversed the increase in cell viability and tube formation that was induced by hypoxia/VEGF/H2O2. Additionally, treatment with an inhibitor of hypoxia inducible factor (HIF)­1α (KC7F2) and MLT synergistically reduced the release of ROS and VEGF, and inhibited cell viability and tube formation of HUVECs. These observations demonstrate that MLT may serve dual roles in the inhibition of angiogenesis, as an antioxidant and a free radical scavenging agent. MLT suppresses the viability and angiogenesis of HUVECs through the downregulation of HIF­1α/ROS/VEGF. In summary, the present data indicate that MLT may be a potential anticancer agent in solid tumors with abundant blood vessels, particularly combined with KC7F2.

miRNA­26a­5p and miR­26b­5p inhibit the proliferation of bladder cancer cells by regulating PDCD10.

MicroRNA (miR)­26a­5p and miR­26b­5p consistently play an antitumor role in many types of cancers, but the underlying mechanism remains unclear in bladder cancer (BC). In the present study, we found that, in BC tissues, the levels of miR­26a­5p and miR­26b­5p were lower than in paired normal tissues. The upregulation of miR­26­5p significantly inhibited the proliferation of BC cell lines (T24 and 5637). Bioinformatics analysis indicated that Programmed Cell Death 10 (PDCD10) was the downstream target gene of miR­26a­5p/miR­26b­5p, and this was ascertained by western blotting and quantitative real­time reverse transcription PCR (RT­qPCR). In addition, in the 3'­UTR of PDCD10, the binding site was identified using a luciferase reporter assay. We determined that clinical BC tissues presented higher PDCD10 levels than adjacent normal tissues and that PDCD10 promoted proliferation of BC cell lines. Overexpression of miR­26a­5p/miR­26b­5p inhibited the stimulatory effect on proliferation of BC cells induced by PDCD10. In addition, in vivo experiments and clinical data revealed that the prognosis of BC patients with high expression of miR­26a­5p/miR­26b­5p and low expression of PDCD10 was better than that of patients with low miR­26­5p and high PDCD10 expression. These data revealed that miR­26a­5p and miR­26b­5p were pivotal regulators in BC progression by targeting the proliferation­related protein, PDCD10. The miR­26­5p/PDCD10 interaction may provide important insight into the pathway of BC progression and present novel opportunities for future diagnosis and treatment strategies, especially for patients with high levels of PDCD10.

High Glucose Promotes Epithelial-Mesenchymal Transition of Uterus Endometrial Cancer Cells by Increasing ER/GLUT4-Mediated VEGF Secretion.

BACKGROUND/AIMS: Uterus endometrial cancer (UEC) is the common malignancy among gynecologic cancers, and most of them are type I estrogen-dependent UEC. Diabetes is well-known risk factor for the development of UEC. However, the underlying link between high glucose (HG) and the estrogen receptor in UEC remains unclear. Epithelial-mesenchymal transition (EMT) has also been shown to occur during the initiation of metastasis in cancer progression. The aim of this study was to determine the relationships and roles of HG, estrogen receptor and EMT in the growth and migration of UEC. METHODS: The expression of glucose transport protein 4 (GLUT4) in the control endometrium and UEC tissues was detected by immunohistochemistry (IHC); the cell viability and invasion were analyzed through CCK-8 and Matrigel invasion assays; the transcriptional level of EMT-related genes was evaluated through real-time PCR; and the effect of HG and / or GLUT4 on estrogen receptors, vascular endothelial growth factor (VEGF) and its receptor VEGFR was analyzed through western blotting, ELISA and flow cytometry (FCM) assay, respectively. In addition, Ishikawa-xenografted nude mice were constructed and were used to analyze the effect of estrogen and GLUT4 on the growth of UEC in vivo. RESULTS: Here, we found that exposure to HG led to a high level of viability and invasion of UEC cell lines (UECC, Ishikawa and RL95-2 cells). Compared with the normal endometrium, a higher level of GLUT4 was observed in UEC tissues. Silencing GLUT4 obviously inhibited the HG-promoted viability, invasion and expression of EMT-related genes (TWIST, SNAIL and CTNNB1) of UECC promoted by HG. Further analysis showed that HG and GLUT4 promoted the secretion of VEGF and expression of VEGFR in UECC. Treatment with HG led to the increase of estrogen receptor α (ERα) and ß (ERß) in UECC, blocking ERα or ERß resulted in the decreases in GLUT4 expression, TWIST, SNAIL and CTNNB1 transcription, and VEGF and VEGFR expression in UECC. Treatment with anti-human VEGF neutralizing antibody restricted the viability and invasion of UECC that was induced by HG and estrogen. Exposure to estrogen accelerated growth, VEGF production, and TWIST and CTNNB1 expression in UEC in Ishikawa-xenografted nude mice, and silencing GLUT4 restricted these effects. CONCLUSION: These data suggest that HG increases GLUT4 and VEGF/VEGFR expression, further promotes EMT process and accelerates the development of UEC by up-regulating ER.

Cisplatin inhibits the progression of bladder cancer by selectively depleting G-MDSCs: A novel chemoimmunomodulating strategy.

Bladder cancer (BC) is a disease arising from the malignant cells of the urinary bladder. Myeloid-derived suppressor cells (MDSCs) expand broadly and have strong immunosuppressive activities in the cancer microenvironment. Determining how to inhibit the negative effects of MDSCs requires immediate attention. In this study, we found that granulocytic-MDSCs (G-MDSCs), which constitute one of the two types of MDSCs, were significantly increased in BC tissues compared with those in the adjacent bladder tissues. There was a robust negative correlation between the G-MDSCs and the CD8+ T cells in the BC tissues. In this study, we attempted to identify pharmacological approaches to eliminate MDSCs and restore T cell anti-tumor activities. It is necessary to explore a method to eliminate the detrimental effects of MDSCs. Cisplatin, a chemotherapy medication used to treat BC, not only rapidly kills proliferating cancer cells but also affects the tumor immune microenvironment. However, the mechanism underlying this phenomenon is largely unknown. In this study, we found that Cisplatin directly inhibited the proliferation and induced the apoptosis of T24 cells (a BC cell line), as well as decreased the percentage of the G-MDSCs in the population of peripheral blood mononuclear cells (PBMCs), which restored the expansion of the CD8+ T cells. In the C3H/He mouse BC model, Cisplatin treatment inhibited the progression of BC and effectively decreased the proportion of G-MDSCs. These results suggest that Cisplatin treatment enhances the anti-tumor function of CD8+ T cells by decreasing G-MDSCs. This finding provides a new perspective for Cisplatin treatment to prevent the progression of BC, particularly in patients with abnormally high levels of G-MDSCs.

The role of the SDF-1/ CXCR7 axis on the growth and invasion ability of endometrial cancer cells.

PURPOSE: Stroma-derived factor-1 (SDF-1) and its receptor C-X-C chemokine receptor-4 (CXCR4) are involved in human endometrial carcinoma (EC) progression. CXCR7 is another important receptor of SDF-1 and has a higher affinity with SDF-1 compared with that of CXCR4. This paper aims to study the effects of the SDF-1/CXCR7 axis on the growth and invasion ability of EC cells. METHODS: CXCR7 expression was evaluated by quantitative RT-PCR, immunohistochemistry, immunocytochemistry and Western blotting in EC cell lines and 30 cases of primary EC tissue from patients. EC cell line proliferation and migration were assessed following knockdown of CXCR7 by MTT and transwell assays. RESULTS: The results showed that CXCR7 was highly expressed at both mRNA and protein levels in the EC cells and tissue. siCXCR7 effectively silenced CXCR7 in Ishikawa and AN3CA cells. Treatment with 17ß-oestradiol (17ß-E2) significantly increased the levels of CXCR7 and SDF-1 in Con, siCon and siCXCR7 treated Ishikawa. siCXCR7 persistently inhibited CXCR7 expression, even in cells treated with 17ß-E2. Moreover, in vitro functional analyses, silencing CXCR7 resulted in decreased proliferation in Ishikawa and AN3CA cells. Treatment with 17ß-E2 and SDF-1 significantly promoted the growth and migration in siCon treated Ishikawa and AN3CA. Interestingly, in response to 17ß-E2 and SDF-1 stimulation, siCXCR7 continuously inhibited the growth and invasion of Ishikawa and AN3CA cells. CONCLUSION: Our results indicate that SDF-1/CXCR7 plays a positive role in the proliferation and invasion of EC cells. CXCR7 inhibition treatment may provide a promising strategy for anti-tumour therapy for EC.

Mutant p53 induces EZH2 expression and promotes epithelial-mesenchymal transition by disrupting p68-Drosha complex assembly and attenuating miR-26a processing.

The tumor suppressor p53 and the transcriptional repressor Enhancer of Zeste Homolog 2 (EZH2) have both been implicated in the regulation of epithelial-mesenchymal transition (EMT) and tumor metastasis via their impacts on microRNA expression. Here, we report that mutant p53 (mutp53) promotes EMT in endometrial carcinoma (EC) by disrupting p68-Drosha complex assembly. Overexpression of mutp53 has the opposite effect of wild-type p53 (WTp53), repressing miR-26a expression by reducing pri-miR-26a-1 processing in p53-null EC cells. Re-expression of miR-26a in mutp53 EC cells decreases cell invasion and promotes mesenchymal-epithelial transition (MET). Rescuing miR-26a expression also inhibits EZH2, N-cadherin, Vimentin, and Snail expression and induces E-cadherin expression both in vitro and in vivo. Moreover, patients with higher serum miR-26a levels have a better survival rate. These results suggest that p53 gain-of-function mutations accelerate EC tumor progression and metastasis by interfering with Drosha and p68 binding and pri-miR-26a-1 processing, resulting in reduced miR-26a expression and EZH2 overexpression.

Interleukin 6 promotes endometrial cancer growth through an autocrine feedback loop involving ERK-NF-κB signaling pathway.

Interleukin (IL)-6 as an inflammation factor, has been proved to promote cancer proliferation in several human cancers. However, its role in endometrial cancer has not been studied clearly. Previously, we demonstrated that IL-6 promoted endometrial cancer progression through local estrogen biosynthesis. In this study, we proved that IL-6 could directly stimulate endometrial cancer cells proliferation and an autocrine feedback loop increased its production even after the withdrawal of IL-6 from the medium. Next, we analyzed the mechanism underlying IL-6 production in the feedback loop and found that its production and IL-6-stimulated cell proliferation were effectively blocked by pharmacologic inhibitors of nuclear factor-kappa B (NF-κB) and extra-cellular signal-regulated kinase (ERK). Importantly, activation of ERK was upstream of the NF-κB pathways, revealing the hierarchy of this event. Finally, we used an orthotopic nude endometrial carcinoma model to confirm the effects of IL-6 on the tumor progression. Taken together, these data indicate that IL-6 promotes endometrial carcinoma growth through an expanded autocrine regulatory loop and implicate the ERK-NF-κB pathway as a critical mediator of IL-6 production, implying IL-6 to be an important therapeutic target in endometrial carcinoma.

Activation of a positive feedback loop involving IL-6 and aromatase promotes intratumoral 17ß-estradiol biosynthesis in endometrial carcinoma microenvironment.

Tumor-stroma interactions contribute greatly to intratumoral estrogen biosynthesis in endometrial carcinoma, but the mechanisms involved remain largely unknown. Previous study demonstrated that intratumoral aromatase upregulation in stromal cells participated in this process, but the specific aromatase-regulators have not been reported. In the present study, we found that aromatase expression in intratumoral stroma, but not in tumor epithelium, correlated positively with interleukin 6 (IL-6) expression in cancer epithelial cells by immunohistochemistry, which was confirmed using laser capture microdissection/real-time reverse transcription-PCR. With stimulation by exogenous IL-6, aromarase expression was increased in stromal cells not but not in cancer cells. Aromatase mRNA levels in endometrial cancer cells were not influenced by cocultivation with intratumoral stromal cells. When cocultured with 17ß-estradiol (E2 )-treated cancer cells, aromatase mRNA in stromal cells was significantly elevated and increased IL-6 protein levels were detected in E2 -treated culture medium. Next, we demonstrated that E2 -induced IL-6 production was through cooperation between estrogen receptor α and nuclear factor-kappa B. Furthermore, an IL-6 receptor blocking antibody could attenuate the upregulation of aromatase expression in stromal cells and the E2 concentration in coculture systems of cancer and stromal cells. The results were confirmed by an orthotopic nude endometrial carcinoma model in vivo. These studies elucidated the activation of a positive feedback loop, that is, IL-6 stimulated by E2 in endometrial cancer cells induced aromatase expression in stromal cells, promoting enhanced intratumoral E2 synthesis. Blocking of this tumor-stroma interaction may be a therapeutic strategy to overcome in situ estrogen biosynthesis in endometrial carcinoma.

The decidual stromal cells-secreted CCL2 induces and maintains decidual leukocytes into Th2 bias in human early pregnancy.

The precise mechanism of characteristic Th2 predominance at maternal-fetal interface remains unresolved. In the present study, we investigated roles of the decidua-derived CCL2 in Th2 predominance at maternal-fetal interface. FCM shows that 55% CD56(+)CD16(-)CD3(-) decidual NK, 52% CD4(+) T cells and 75% CD14(+) monocytes express CCR2. Recombinant human CCL2 (rhCCL2) and the decidual stromal cells (DSCs)-derived supernatant can enhance proliferation and inhibit apoptosis of these decidual leukocytes (DLCs), and promote Th2 cytokines production, IL-4 and IL-10, with an increase in GATA-3 transcription. They also inhibit the secretion of Th1 cytokines, TNF-α and IFN-γ, with a decrease in T-bet transcription It is concluded that the secreted CCL2 by decidual stromal cells increases GATA-3 transcription and decreases T-bet transcription in the decidual leukocytes, which contributes to Th2 polarization at maternal-fetal interface. Furthermore, the Th2 cytokines, IL-4 and IL-10, rather than Th1 cytokines, was shown to increase CCL2 secretion of DSC.

The G protein-coupled receptor GPR30 mediates the proliferative and invasive effects induced by hydroxytamoxifen in endometrial cancer cells.

The selective ER modulator tamoxifen (TAM(1)) is the most widely used ER antagonist for treatment of women with hormone-dependent breast tumor. However, long-term treatment is associated with an increased risk of endometrial cancer. The aim of the present study was to demonstrate new insight into the role of G-protein coupled receptor 30 (GPR30) in the activity of TAM, which promoted endometrial cancer. In endometrial cancer cell lines ISHIKAWA and KLE, the potential of 4-hydroxytamoxifen (OHT), the active metabolite of TAM, 17ß-estradiol (E2) and G1, a non-steroidal GPR30-specific agonist to promote cell proliferation and invasion was evaluated. All agents above induced high proliferative and invasive effects, while the down-regulation of GPR30 or the interruption of MAPK signal pathway partly or completely prevented the action of the regent. Moreover, the RNA and protein expression of GPR30 was up-regulated by G1, E2 or OHT in both cell lines. The present study provided a new insight into the mechanism involved in the agonistic activity exerted by TAM in the uterus.

Estrogenic transmembrane receptor of GPR30 mediates invasion and carcinogenesis by endometrial cancer cell line RL95-2.

PURPOSE: The mechanisms underlying the effects of estrogen on endometrial cancer remain undefined. Although the classical mechanism of the action of estrogen involves binding to the estrogen receptors α and ß, and transduction of the signal into the cell, G protein-coupled receptor (GPR) 30 has been shown to mediate nongenomic estrogen signaling. The goal of this study was to determine the role of GPR30 signal in the basic process such as invasion and carcinogenesis of endometrial cancer. METHODS: We downregulated the expression of GPR30 in endometrial cancer cell line RL95-2 by transfection with shGPR30-pGFP-V-RS, a GPR30 antisense expression vector. The cells were then subjected to an MTT assay and a Transwell(®) migration assay. And an animal model was also used to investigate the influence of downregulation of GPR30 on oncogenesis. RESULTS: Downregulation of GPR30 led to reduced growth and invasion by cells treated with 17ß-estradiol. And the capacity of transfected RL95-2 cells to promote tumorigenesis was weakened in vivo. CONCLUSIONS: Our data suggest that, for the endometrial cancer cell line RL95-2, GPR30 plays important roles in mediating the proliferative and invasive effects of estrogen and in tumorigenesis.

Crosstalk between estrogen receptor and mitogen-activated protein kinase signaling in the development and progression of endometrial cancer.

OBJECTIVE: The objectives of the study were to evaluate the role of mitogen-activated protein kinase (MAPK) signaling in normal, hyperplastic, and neoplastic endometrium in relation to estrogen receptor (ER) status and to investigate whether 17ß-estradiol (E2) and tamoxifen (TAM) mediate the proliferation and apoptosis of endometrial cancer cells through the MAPK pathway. METHODS: The expressions of phosphorylated and total extracellular signal-regulated kinases 1/2 (phosphorylated extracellular signal-regulated kinase 1/2 [p-ERK1/2] and total ERK1/2 [t-ERK1/2]) were analyzed with immunohistochemistry in normal, hyperplastic, and neoplastic endometrium. The expression levels of p-ERK1/2 and t-ERK1/2 in RL95-2 and KLE after stimulation by E2, progesterone (P), and TAM were detected by Western blotting. The effects of E2 and TAM in combination with MAPK pathway inhibitors on the growth and apoptosis of endometrial cancer cells were examined by the MTS assay and flow cytometry analysis. RESULTS: The expression level of p-ERK1/2 was significantly associated with the International Federation of Gynecology and Obstetrics stage (P = 0.0072). The ratio of phosphorylated/total ERK1/2 was higher in ER-positive endometrial cancer tissues and cells (P < 0.05). 17ß-Estradiol increased ERK1/2 phosphorylation, and TAM decreased ERK1/2 phosphorylation in endometrial cancer cell lines within 30 minutes (P < 0.05). The MEK1/2 inhibitor, U0126, and the stress-activated protein kinase/c-Jun NH2-terminal kinase inhibitor, SP600125, significantly suppressed the proliferation of human endometrial cancer cell lines RL95-2 and KLE induced by E2 (P < 0.05). The level of TAM-induced apoptosis was greater in KLE than in RL95-2 cells, and the p38 cascade was involved in the TAM-induced apoptosis of both cell lines (P < 0.05). CONCLUSIONS: The cross-talk between MAPK signaling and ER status might exert a key role in progression of endometrial cancer. Furthermore, the effects of E2 or TAM on the proliferation or apoptosis of ER-positive and ER-negative endometrial cancer cells were mediated through distinct MAPK pathways. These mechanisms might contribute to ER-specific differences in MAPK activation for molecular-target therapies in endometrial carcinoma.

Aberrant methylation of breast and ovarian cancer susceptibility gene 1 in chemosensitive human ovarian cancer cells does not involve the phosphatidylinositol 3'-kinase-Akt pathway.

Methylation is an important silencing mechanism of breast and ovarian cancer susceptibility gene 1 (BRCA1) expression in sporadic ovarian cancer. However, the role of BRCA1 methylation in chemotherapy in sporadic ovarian cancer and the related pathways have not been understood completely. This study has determined the roles of BRCA1 hypermethylation in chemotherapy of sporadic ovarian cancer and its related signaling pathways. We used bisulfite sequencing, real-time polymerase chain reaction, and western blotting to check the methylation state and expression levels of BRCA1 of the following cell lines: platinum-sensitive human ovarian cancer cell line COC1, platinum-resistant cell line COC1/DDP, SKOV-3, and 5-Aza-dC treated COC1. The cisplatin sensitivity of ovarian cancer cells was examined by MTS (methyl-thiazol tetrazolium) assay. Tumorigenicity in vivo and DDP-based chemosensitivity were compared among the above cells. Phosphatidylinositol 3'-kinase (PI3K)-Akt pathway activation in ovarian cancer cells was studied by western blotting. The frequency of BRCA1 methylation in the COC1 cell line was higher than in COC1/DDP and SKOV-3 cell lines, whereas the mRNA and protein expression of BRCA1 were lower than in the COC1/DDP and SKOV-3 cell lines. DNA demethylation decreased the chemosensitivity of COC1 cells and partially increased the expression levels of BRCA1. The activation of the PI3K-Akt pathway was low in ovarian cancer cells. Our results indicate that hypermethylation of BRCA1 might play an important role in the chemosensitivity of ovarian cancer, and that the PI3K-Akt pathway is not involved in this response.

Kallikrein 4 overexpression in endometrial carcinoma and upregulation by estrogen via mitogen-activated protein kinase signal pathway.

OBJECTIVE: The aim of this study was to investigate the expression of kallikrein 4 (KLK4) and the potential signal pathway through which estrogen up-regulates KLK4 in endometrial cancer. METHODS: The expression of KLK4 was analyzed in 15 human normal endometrium, 13 hyperplasia endometrium, and 68 endometrioid adenocarcinoma by immunohistochemistry. After exposure to 17beta-estradiol and/or to the mitogen-activated protein kinase (MAPK) inhibitor U0126 and to the PI3K inhibitor LY294002, the expression of KLK4 in the endometrial cancer cell lines KLE and RL95-2 was detected with quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blot. RESULTS: The expression of KLK4 protein was higher in endometroid endometrial cancer than in hyperplasia or normal endometrium (P < 0.001). Immunohistochemical staining revealed that 92.6% (63/68) of endometrial adenocarcinoma, 61.5% (8/13) of hyperplasia endometrium, and 26.7% (4/15) of normal endometrium were positive for KLK4 protein. The expression of KLK4 was significantly associated with tumor grade (P = 0.004), but not with ER status (P = 0.532). Quantitative reverse transcriptase PCR and Western blot analysis showed that estrogen can up-regulate the expression of KLK4 in endometrial cancer cell lines KLE and RL95-2, and the up-regulation effect of 17beta-estradiol on KLK4 can be inhibited by U0126 in the 2 endometrial cancer cell lines but not by LY294002. CONCLUSIONS: Kallikrein 4 is a new nuclear protein, and estrogen up-regulates the expression of KLK4 by activating the MAPK pathway in endometrial cancer cell lines, which may play an important role in the development of endometrial cancer.

Estrogenic G protein-coupled receptor 30 signaling is involved in regulation of endometrial carcinoma by promoting proliferation, invasion potential, and interleukin-6 secretion via the MEK/ERK mitogen-activated protein kinase pathway.

The regulatory mechanism of endometrial carcinoma and the signal transduction pathways involved in hormone action are poorly defined. It has become apparent that the G protein-coupled receptor (GPR) 30 mediates the non-genomic signaling of 17beta-estradiol (E2). Here we show that GPR30 is highly expressed in endometrial cancer tissues and cancer cell lines and positively regulates cell proliferation and invasion. GPR30 expression was detected in 50 human endometrial carcinomas. The transcription level of GPR30 was significantly higher in the tissue of endometrial carcinoma than in normal endometrium (P < 0.05). Immunohistochemical assays revealed that the positive expression rate of GPR30 protein in endometrial carcinoma tissue (35/50, 70%) was statistically higher than in normal endometrium tissue (8/30, 26.67%) (chi2 = 14.16, P = 0.0002). GPR30 overexpression was correlated with high-grade endometrial carcinoma. GPR30 expression was also found in two human endometrial cancer cell lines: RL95-2 (estrogen receptor positive) and KLE (estrogen receptor negative). The roles of GPR30 in proliferative and invasive responses to E2 and G1, a non-steroidal GPR30-specific agonist, in RL95-2 and KLE cell lines were then explored. We showed that E2 and G1 could initiate the MAPK/ERK mitogen-activated protein kinase pathway in both cell lines. What's more, E2 and G1 promoted KLE and RL95-2 proliferation and stimulated matrix metalloproteinase production and activity via the GPR30-mediated MEK/ERK mitogen-activated protein kinase pathway, as well as increased interleukin-6 secretion. These findings suggest that GPR30-mediated non-genomic signaling could play an important role in endometrial cancer.

[Anoikis-suppression and invasion induced by tyrosine kinase receptor B in OVCAR3 ovarian cancer cells].

OBJECTIVE: To study the relationship between tyrosine kinase receptor B (TrkB) expression and anoikis-suppression and invasion in OVCAR3 ovarian cancer cells. METHODS: The expression of TrkB mRNA in OVCAR3 ovarian cancer cells under two culture conditions: adhesive cells and cell-spheroids were evaluated by RT-PCR and real-time PCR. The relationship between TrkB expression and anoikis-suppression of OVCAR3 ovarian cancer cells was examined by RNA interference (RNAi) technic, anchorage independent culture and fluorescence-activated cell sorting analysis. The difference in invasion and metastatic ability of OVCAR3 cells under two culture conditions and with or without TrkB silenced by small interfering RNA (siRNA) was investigated by matrigel invasion assay and in vivo studies. RESULTS: The expression of TrkB mRNA was highest in OVCAR3 ovarian cancer cells, 0.0240 +/- 0.0017, compared with the other three cell lines, 0.0030 +/- 0.0006, 0.0027 +/- 0.0009 and 0.0087 +/- 0.0003 respectively, and the expression in OVCAR3 multicellular spheroids was significantly higher than that in cells under monolayer adhesive culture, 0.0437 +/- 0.0021 versus 0.0240 +/- 0.0017 (P < 0.01). TrkB mediated anoikis-suppression in OVCAR3 ovarian cancer cells. OVCAR3 multicellular spheroids had a higher invasion ability than OVCAR3 cells under monolayer adhesive culture, and the penetrating cells of the two groups were 71.8 +/- 0.8 and 47.7 +/- 0.8 respectively (P < 0.01). The metastatic ability of OVCAR3 cells was attenuated when TrkB was silenced, and the volume of the tumors developed by OVCAR3 adhesive cells and OVCAR3 adhesive cells with TrkB silenced were (16.3 +/- 4.7) mm(3) and (6.0 +/- 1.4) mm(3) respectively (P < 0.01). CONCLUSION: As an anoikis-suppressor, TrkB may increase the invasion and metastasis of OVCAR3 ovarian cancer cells.