目的 探究妊娠期糖尿病大鼠子宫内膜组织中核因子κB(NF-κB)及葡萄糖转运蛋白4(GLUT4)表达与胰岛素抵抗发生的相关性.方法 选取40只SD怀孕大鼠,将其按照随机数字表法分成正常组和模型组,每组各20只.正常组孕鼠腹腔注射给予柠檬酸钠缓冲液,模型组孕鼠给予链脲佐菌素(45 mg/kg),2组剂量一致.于分娩前检测孕鼠的空腹血糖和体重,分娩后处死孕鼠,取子宫内膜组织.采用葡萄糖氧化酶法检测空腹血糖和空腹胰岛素.采用酶联免疫吸附试验法检测血清可溶性E-选择素(sE-selectin)和可溶性细胞间黏附分子(sICAM-1)水平,采用免疫组织化学法检测子宫内膜中NF-κB、GLUT4的表达.结果 模型组孕鼠的空腹血糖值显著高于正常组,体重显著低于正常组(P<0.05).模型组孕鼠的HOMA-IR值(36.19±5.70)显著高于正常组(15.20±2.50),差异有统计学意义(P<0.05).模型组孕鼠血清sE-selectin和sICAM-1水平为(67.02±24.01)、(411.02±123.01)μg/mL,均显著高于正常组[(40.11±15.02)、(245.04±77.03)μg/mL],差异均有统计学意义(P<0.05).模型组孕鼠子宫内膜中NF-κB的阳性表达率(70.00％)显著高于正常组(35.00％),而GLUT4的阳性表达率(40.00％)显著低于正常组(80.00％),差异均有统计学意义(P<0.05).NF-κB、sE-selectin、sICAM-1的水平与HOMA-IR值呈正相关关系(P<0.05),GLUT4水平与HOMA-IR值呈负相关关系(P<0.05).结论 妊娠期糖尿病胰岛素的发生伴随着孕鼠子宫内膜组织中NF-κB表达上调和GLU4表达下调,并与血清中sE-selectin、sICAM-1水平上升密切相关.

OBJECTIVE:To explore the mechanism by which ginsenoside 20(S)-Rg3 upregulates the expression of tumor suppressor von Hippel-Lindau (VHL) gene in ovarian cancer cells.METHODS:Ovarian cancer cell line SKOV3 treated with 20(S)-Rg3 were examined for mRNA and protein levels of VHL, DNMT1, DNMT3A and DNMT3B by real-time PCR and Western blotting, respectively. The changes in VHL mRNA expression in SKOV3 cells in response to treatment with 5-Aza-CdR, a DNA methyltransferase inhibitor, were detected using real-time PCR. VHL gene promoter methylation was examined with methylation-specific PCR and VHL expression levels were determined with real-time PCR and Western blotting in non-treated or 20(S)-Rg3-treated SKOV3 cells and in 20(S)-Rg3-treated DNMT3A-overexpressing SKOV3 cells. VHL and DNMT3A protein levels were detected by immunohistochemistry in subcutaneous SKOV3 cell xenografts in nude mice.RESULTS:Treatment of SKOV3 cells with 20(S)-Rg3 significantly upregulated VHL and downregulated DNMT3A expressions at both the mRNA and protein levels (P < 0.05) and upregulated DNMT3B expression only at the mRNA level, but did not cause significant changes in either the mRNA or protein level of DNMT1. Treatment of the cells with 2 and 5 μmol/L 5-Aza-CdR obviously increased VHL mRNA expression by by over 3 folds (P < 0.05). 20(S)-Rg3 significantly decreased the methylation level in the promoter region of VHL gene, and this effect was abrogated by DNMT3A overexpression in the cells (P < 0.05). Immunohistochemisty showed a significantly increased VHL expression but a lowered DNMT3A expression in subcutaneous SKOV3 cell xenografts in 20 (S)-Rg3-treated nude mice.CONCLUSIONS:Ginsenoside 20(S)-Rg3 upregulates VHL expression in ovarian cancer cells by suppressing DNMT3A-mediated DNA methylation.

目的明确人参皂苷20（S）-Rg3促进卵巢癌细胞抑癌基因von Hippel-Lindau（VHL）表达的机制。方法 Real-time PCR和Western blotting检测20（S）-Rg3处理前后卵巢癌细胞SKOV3中的VHL、DNA甲基转移酶DNMT1、DNMT3A和DNMT3B的mRNA和蛋白水平。Real-time PCR检测甲基转移酶抑制剂5-氮杂-2-脱氧胞苷（5-Aza-CdR）处理卵巢癌细胞SKOV3前后VHL的mRNA水平变化。甲基化特异性PCR（MSP）检测20（S）-Rg3单纯处理组和20（S）-Rg3处理且过表达DNMT3A组的VHL基因启动子区的甲基化水平,并检测VHL的mRNA和蛋白表达水平。免疫组化检测课题组前期获得的20（S）-Rg3处理组及对照组的裸鼠皮下移植瘤组织中VHL和DNMT3A的蛋白表达。结果 20（S）-Rg3处理后,卵巢癌细胞SKOV3中VHL的mRNA水平升高到阴性对照细胞的2倍以上,蛋白水平亦上调（P＜0.05）;DNMT3A的mRNA水平和蛋白水平均下降（P＜0.05）,DNMT3B的mRNA水平略有升高但蛋白水平无明显变化（P＞0.05）,DNMT1的mRNA和蛋白水平均无变化（P＞0.05）。2μmol/L和5μmol/L的5-Aza-CdR处理后,SKOV3细胞的VHL m RNA水平升高到阴性对照细胞的3倍以上（P＜0.05）。20（S）-Rg3使VHL基因启动子区的甲基化水平降低（P＜0.05）,在20（S）-Rg3处理的同时过表达DNMT3A,则VHL基因启动子甲基化水平再次升高,同时VHL mRNA和蛋白水平均降低（P＜0.05）。免疫组织显示,相对于对照组,20（S）-Rg处理组的裸鼠皮下移植瘤组织中VHL的表达上调、DNMT3A的表达下调。结论 20（S）-Rg3通过抑制DNMT3A介导的启动子甲基化而促进卵巢癌细胞中VHL的表达。

Tripartite motif-containing protein 26 (TRIM26) is a member of the TRIM protein family and has been demonstrated to play crucial roles in several types of cancers. However, the biological role of TRIM26 in bladder cancer and the mechanism have not been studied. In this study, we investigated the expression of TRIM26 in bladder cancer tissues and their adjacent non-tumor tissues by Western blot and qRT-PCR. In vitro investigations were performed to assess the roles of TRIM26 in bladder cancer using TRIM26-silencing and TRIM26-overexpressing bladder cancer cell lines. MTT and EdU assays were performed to evaluate cell proliferation. Cell migration and invasion were determined by transwell assays. Western blot analysis was performed to detect the expression levels of p-Akt, Akt, p-GSK3β, GSK3β, β-catenin and c-Myc. Our results showed that TRIM26 expression was upregulated in human bladder cancer tissues and cell lines at both mRNA and protein levels. Knockdown of TRIM26 significantly inhibited the proliferation, migration and invasion of bladder cancer cells. In contrast, TRIM26 overexpression promoted bladder cancer cell proliferation, cell migration and invasion. Furthermore, knockdown of TRIM26 significantly decreased the levels of p-Akt, p-GSK3β, β-catenin and c-Myc in bladder cancer cells. Additionally, induction of Akt by SC79 treatment reversed the inhibitory effects of TRIM26 knockdown on the cellular behaviors of bladder cancer cells, while inhibition of β-catenin reversed the effects of TRIM26 overexpression on the behaviors. Finally, knockdown of TRIM26 attenuated the growth of tumor xenografts in nude mice. In conclusion, these findings demonstrated that TRIM26 exerted an oncogenic role in bladder cancer through regulation of cell proliferation, migration and invasion via the Akt/GSK3β/β-catenin pathway.

Emerging evidence suggests that miR-143 plays an important role in the regulation of tumor sensitivity to chemotherapeutic agents. The study explores the underlying mechanism of miR-143 in reversing cisplatin resistance in ovarian cancer. The cisplatin-resistant ovarian cancer cell line A2780/CDDP was induced and established via treating A2780 cells by gradually increasing cisplatin concentrations. The IC50 values of A2780/CDDP and A2780 to cisplatin were 218.10 ± 1.12 and 21.99 ± 1.12 μM, respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) results showed that miR-143 was significantly decreased in A2780/CDDP cells compared with A2780 cells. miR-143 overexpression decreased cisplatin resistance in A2780/CDDP, and miR-143 inhibition decreased A2780 sensitivity to cisplatin. Results of qRT-PCR, Western blot analysis, and luciferase reporter assay indicated that the direct target of miR-143 was DNMT3A, which, in turn, was upregulated in A2780/CDDP. DNMT3A overexpression antagonized the sensitizing effect of miR-143 on A2780/CDDP to cisplatin. Knocking down of DNMT3A reduced cisplatin resistance in A2780/CDDP, while overexpression of DNMT3A increased cisplatin resistance in A2780. Methylation-specific polymerase chain reaction results showed that the methylation level in the promoter region of the miR-143 precursor gene was higher in A2780/CDDP cells than in A2780 cells. DNMT3A mediated the hypermethylation of the miR-143 precursor gene, resulting in miR-143 downregulation in A2780/CDDP. miR-143 inhibited cell growth of A2780/CDDP cell in nude mice. Our findings indicated the negative feedback between miR-143 and DNMT3A as a crucial epigenetic modifier of cisplatin resistance in ovarian cancer.

Epithelial-mesenchymal transition (EMT) is one of the key mechanisms mediating cancer progression. MicroRNAs (miRs) are essential regulators of gene expression by suppressing translation or causing degradation of target mRNA. Growing evidence illustrates the crucial roles of miRs dysregulation in cancer development and progression. Here, we have found for the first time that the ginsenoside 20(S)-Rg3, a pharmacologically active component of Panax ginseng, potently increases miR-145 expression by downregulating methyltransferase DNMT3A to attenuate the hypermethylation of the promoter region in the miR-145 precursor gene. Restoration of DNMT3A reverses the inhibitory effect of 20(S)-Rg3 on EMT. FSCN1 is verified as the target of miR-145 to suppress EMT in human ovarian cancer cells. The results from nude mouse xenograft models further demonstrate the suppressive effect of miR-145 on malignant progression of ovarian cancer. Taken together, our results show that 20(S)-Rg3 blocks EMT by targeting DNMT3A/miR-145/FSCN1 pathway in ovarian cancer cells, highlighting the potentiality of 20(S)-Rg3 to be used as a therapeutic agent for ovarian cancer.

BACKGROUND:Many microRNAs (miRs) are dysregulated in cancers, and aberrant miR expression patterns have been suggested to correlate with chemo-resistance of cancer cells. We aim to study the role of miR-30 family members in cisplatin-resistance of ovarian cancer cells.METHODS:qRT-PCR was used to compare differential expression levels of miR-30 family members in ovarian cancer cell line A2780 and its cisplatin-resistant derivative CP70. Changes of cisplatin-sensitivity in miR-30a-5p- and miR-30c-5p-overexpressed-CP70 cells and miR-30a-5p- and miR-30c-5p-inhibited-A2780 cells were examined by CCK8 assay and apoptosis analysis using flow cytometry; targets of miR-30a/c-5p were analyzed by western blotting and luciferase reporter assay; methylation regulation of pre-miR-30a/c-5p was examined by methylation specific PCR.RESULTS:miR-30a-5p and miR-30c-5p, in contrast to other miR-30 family members, dramatically decreased in cisplatin-resistant CP70 cells due to overexpressed-DNMT1 induced aberrant methylation. miR-30a/c-5p in turn directly inhibited DNMT1 as well as Snail. Forced expression of miR-30a/c-5p or knocking down of DNMT1 and Snail promoted cisplatin susceptibility and partially reversed epithelial-mesenchymal transition (EMT) in CP70 cells, while inhibition of miR-30a/c-5p or ectopic expression of DNMT1 and Snail induced cisplatin resistance and partial EMT in cisplatin-sensitive A2780 cells.CONCLUSIONS:A feedback loop between miR-30a/c-5p and DNMT1 is a potent signature for cisplatin-resistance and EMT in ovarian cancer, promising a potential target for improved anti-cancer treatment.

The development of chemo-resistance impairs the outcome of the first line platinum-based chemotherapies for ovarian cancer. Deregulation of DNA methylation/demethylation provides a critical mechanism for the occurrence of chemo-resistance. The ten-eleven translocation (TET) family of dioxygenases including TET1/2/3 plays an important part in DNA demethylation, but their roles in cisplatin resistance have not been elucidated. Using cisplatin-sensitive and cisplatin-resistant ovarian cancer cell models, we found that TET1 was significantly upregulated in cisplatin-resistant CP70 cells compared with that in cisplatin-sensitive A2780 cells. Ectopic expression of TET1 in A2780 cells promoted cisplatin resistance and decreased cytotoxicity induced by cisplatin, while inhibition of TET1 by siRNA transfection in CP70 cells attenuated cisplatin resistance and enhanced cytotoxicity of cisplatin. Increased TET1 induced re-expression of vimentin through active DNA demethylation, and cause partial epithelial-to-mesenchymal (EMT) in A2780 cells. Contrarily, knocking down of TET1 in CP70 cells reduced vimentin expression and reversed EMT process. Immunohistochemical analysis of TET1 in human ovarian cancer tissues revealed that TET1 existed in nucleus and cytoplasm in ovarian cancer tissues. And the expression of nuclear TET1 was positively correlated with residual tumor and chemotherapeutic response. Thus, TET1 expression causes resistance to cisplatin and one of the targets of TET1 action is vimentin in ovarian cancer.

Targeted therapy has revolutionized the therapeutic landscape in oncology in recent years and anti-VEGF agent has been approved for ovarian cancer (OC). Unfortunately, the efficacy of this treatment is limited due to the development of resistance, while the molecular mechanisms underlying OC resistance to anti-VEGF therapy are less clear. In this study, we observed a differential response of OC cells to anti-VEGF agent bevacizumab (BV) by using xenograft models. Gene expression analysis showed that TCEB2 gene was significantly upregulated in the OC tumors with acquired resistance compared with the sensitive tumors. Further mechanism dissections demonstrated that TCEB2 played a critical role in the development of acquired resistance to BV in OC cells via promoting HIF-1α degradation and suppressing VEGF-A expression. In TCEB2 overexpressing cells, interleukin-8 (IL-8) was elevated and functioned as a compensatory angiogenesis signaling which was sensitive to IL-8 monoclonal antibody (IL-8 Ab). The combination of BV and IL-8 Ab exhibited synergistic effect of growth inhibition on both OC and endothelial cells. Thus, this study provides an alternative strategy of simultaneously targeting VEGF-A and IL-8 for combating OC.

BACKGROUND:Abnormal DNA methylation/demethylation is recognized as a hallmark of cancer. TET (ten-eleven translocation) family members are novel DNA demethylation related proteins that dysregulate in multiple malignances. However, their effects on ovarian cancer remain to be elucidated.METHODS:The changes of TET family members during TGF-β1-induced epithelial-mesenchymal transition (EMT) in SKOV3 and 3AO ovarian cancer cells were detected. TET3 was ectopically expressed in TGF-β1-treated ovarian cancer cells to examine its effect on TGF-β1-induced EMT phenotype. The downstream target of TET3 was further identified. Finally, the relationships of TET3 expression to clinic-pathological parameters of ovarian cancer were investigated with a tissue microarray using immunohistochemistry.RESULTS:TET3 was downregulated during TGF-β1-initiatd epithelial-mesenchymal transition (EMT) in SKOV3 and 3AO ovarian cancer cells. Overexpression of TET3 reversed TGF-β1-induced EMT phenotypes including the expression pattern of molecular markers (E-cadherin, Vimentin, N-cadherin, Snail) and migratory and invasive capabilities of ovarian cancer cells. miR-30d was identified as a downstream target of TET3, and TET3 overexpression resumed the demethylation status in the promoter region of miR-30d precursor gene, resulting in restoration of miR-30d (an EMT suppressor of ovarian cancer cells proven in our previous study) level in TGF-β1-induced EMT. We further found that TET3 expression was decreased in ovarian cancer tissues, especially in serous ovarian cancers. The overall positivity of TET3 was inversely correlated with the grade of differentiation status of ovarian cancer.CONCLUSION:Our results revealed that TET3 acted as a suppressor of ovarian cancer by demethylating miR-30d precursor gene promoter to block TGF-β1-induced EMT.