Human epididymis protein 4 promotes P­glycoprotein­mediated chemoresistance in ovarian cancer cells through interactions with Annexin II.

The aim of the present study was to investigate the effects of human epididymis protein 4 (HE4) on drug resistance and its underlying mechanisms. The associations among proteins were detected by immunoprecipitation and immunofluorescence assays. Then, stably transfected cell lines CAOV3­HE4­L and CAOV3­A2­L expressing HE4 short hairpin (sh)RNAs and ANXA2 shRNAs, respectively, were constructed. MTT assay, immunocytochemistry, western blotting, reverse transcription­quantitative polymerase chain reaction (RT­qPCR) and flow cytometry were employed to examine drug sensitivity, as well as the expression and activity of P­glycoprotein (P­gp). HE4 and P­gp in epithelial ovarian cancer tissues were assessed via immunohistochemistry. MicroRNAs that targeted the P­gp gene, ABCB1, were predicted using bioinformatics methods, and their expression was evaluated by RT­qPCR. The common signaling pathways shared by HE4, ANXA2 and P­gp were selected by Gene Set Enrichment Analysis (GSEA). The interaction of HE4, ANXA2 and P­gp were confirmed. P­gp expression was positively associated with HE4 and ANXA2 expression, respectively. Moreover, it was observed that there was no significant rescue of P­gp expression in CAOV3­A2­L cells following the administration of active HE4 protein. In addition, the expression of HE4 and P­gp in ovarian cancer tissues of drug­resistant patients were higher compared with that of the drug­sensitive group (P<0.05). Furthermore, the results revealed that hsa­miR­129­5p was significantly increased accompanied by decreased HE4 or ANXA2 expression and P­gp expression in CAOV3­HE4­L and CAOV3­A2­L cells. GSEA analyses disclosed that HE4, ANXA2 and P­gp genes were commonly enriched in the signaling pathway involved in regulating the actin cytoskeleton. These results indicated that HE4 promotes P­gp­mediated drug resistance in ovarian cancer cells through the interactions with ANXA2, and the underlying mechanism may be associated with decreased expression of hsa­miR­129­5p and dysregulation of the actin cytoskeleton signaling pathway.

TMEFF1 overexpression and its mechanism for tumor promotion in ovarian cancer.

BACKGROUND: Transmembrane protein with epidermal growth factor-like and two follistatin-like domains 1 (TMEFF1) has an anticarcinogenic effect in brain tumors. However, little is known about the role of TMEFF1 in epithelial ovarian cancer (EOC). MATERIALS AND METHODS: TMEFF1 expression in EOC was detected by immunohistochemistry; its relationship with clinical pathological parameters and its influence on prognosis were analyzed. The MTT, scratch, Transwell assays, and flow cytometry were used to assess the malignant behavior of ovarian cancer cell. Changes in node proteins in MAPK and PI3K/AKT signaling pathways and the expression of epithelial-mesenchymal transformation markers were measured by Western blot. The regulatory effect of p53 on TMEFF1 was verified by chromatin immunoprecipitation (ChIP) assay and Western blot. RESULTS: TMEFF1 expression was higher in the EOC group than in the borderline and benign tumor groups and normal ovary group; its high expression was significantly related to International Federation of Gynecology and Obstetrics stage (P=0.024) and independently predicted shorter overall survival (P<0.01). TMEFF1 overexpression in ovarian cancer cells induced increased cellular proliferation, migration, and invasion but reduced apoptosis. In addition, the percentage of phosphorylated node proteins in MAPK and PI3K/AKT signaling pathways increased significantly. The expression of E-cadherin decreased but that of vimentin and N-cadherin increased. After the addition of MAPK (PD98059) and PI3K (GDC-0941) pathway inhibitors, ovarian cancer cells overexpressing TMEFF1 showed suppressed malignant behavior. TMEFF1 protein expression in an ovarian cancer cell lines (CAOV3 and ES-2) was downregulated after the inhibition of TP53. The transcription factor, p53, bound the promoter region of the TMEFF1 gene according to ChIP. CONCLUSION: TMEFF1 is a carcinogenic gene in ovarian cancer and can be regulated by p53 transcription. Through MAPK and PI3K/AKT signaling pathways, TMEFF1 promotes the malignant behavior in EOC. Therefore, TMEFF1 may be considered as a potential therapeutic target for ovarian cancer.

Membranous expressions of Lewis y and CAM-DR-related markers are independent factors of chemotherapy resistance and poor prognosis in epithelial ovarian cancer.

BACKGROUND: Chemotherapy resistance is a common problem faced by patients diagnosed with epithelial ovarian cancer (EOC). Currently there are no specific or sensitive clinical biomarkers that maybe implemented to identify chemotherapy resistance and give insight to prognosis. The aim of this study is to investigate the roles of Lewis y antigen and the markers associated with cell-adhesion-mediated drug resistance (CAM-DR) in patients with EOC. METHODS: 92 EOC patients who were treated with systemic chemotherapy after cytoreductive surgery were included in this analysis. Patients were divided into two groups, chemotherapy sensitive (n = 56) and resistant (n = 36). Immunohistochemical (IHC) staining for Lewis y and CAM-DR-related cell surface proteins including CD44, CD147, HE4 (Human epididymis protein 4), integrin α5, ß1, αv and ß3 were conducted on tissues collected during primary debulking surgery. Using multivariate logistic regressions, IHC results were compared to clinical variables and chemotherapy resistance to determine possible correlations. The relationships between IHC expression and progression-free survival (PFS) and overall survival (OS) were analyzed using Kaplan-Meier method and Cox regression analysis. RESULTS: Membranous expression of Lewis y and all these CAM-DR-related markers were significantly higher in the resistant group than that of the sensitive group (all P < 0.01). Multivariate regression analysis revealed that high expression of Lewis y, CD44, HE4, integrin α5 and ß1 as well as advanced FIGO stage were independent risk factors for chemotherapy resistance (all P < 0.05). Advanced FIGO stage, lymph node metastasis and high expression of Lewis y, CD44, CD147, HE4, integrin α5, ß1 were associated with a shorter PFS and OS (all P < 0.05). Moreover, multivariate COX analysis demonstrated that the following variates were independent predictors of worse PFS and OS survival: late FIGO stage (P = 0.013, 0.049), high expressions of Lewis y (P = 0.010, 0.036), HE4 (P = 0.006, 0.013) and integrin ß1 (PFS, P = 0.003), integrin α5 (OS, P = 0.019). CONCLUSION: Membranous expression of Lewis y and CAM-DR-related markers including CD44, CD147, HE4, integrin α5, ß1, αv and ß3 are associated with the development of chemotherapy resistance. High expression of Lewis y antigen and CAM-DR-related markers including CD44, CD147, HE4, integrin α5 and ß1 are independent markers for PFS and OS, in which Lewis y and HE4 are the most significant.

[Whole Genome Expression Profiling Analysis of Metastasis and Drug-resistance-related Genes in Epithelial Ovarian Cancer Cells].

Objective To investigate the genes associated with higher ability of metastasis and chemotherapic resistance in epithelial ovarian carcinoma (EOC) by using Agilent whole genome oligonucleotide gene chip,with an attempt to further investigate the molecular mechanism of metastasis and chemotherapic resistance of EOC. Methods Oligonucleotide microarrays were used to determine whether gene expression profile might differentiate EOC cell lines (RMG-1-C,COC1 and HO8910) from their sub-lines (RMG-1-H,COC1/DDP and HO8910/PM) with higher ability of metastasis and chemotherapic resistance. Quantitative real-time polymerase chain reaction and immunohistochemical staining validated the microarray results. Results Gene expression profile identified 49 differentially expressed genes that showed≥2.0 fold change. All these differentially expressed genes were involved mainly in gene expression and biopolymer biosynthesis. Interaction network analysis predicted 21 genes participating in the regulatory connection. Highly differential expression of GCET2,CFTR,FOXP1 and GARS genes was validated by quantitative realtime polymerase chain reaction in all cell line samples,and the Results were consistent with microarray findings. Conclusion The change in the metastasis and chemotherapic resistance-associated gene expression profiles may provide a theoretical basis for studies on the molecular mechanisms of metastasis and chemotherapic resistance in EOC.

Lewis Y regulates signaling molecules of the transforming growth factor ß pathway in ovarian carcinoma-derived RMG-I cells.

LeY (Lewis Y) is a difucosylated oligosaccharide carried by glycoconjugates on the cell surface. Elevation of LeY is frequently observed in epithelial-derived cancers and is correlated to pathological staging and prognosis. To study the role of LeY on cancer cells, a stably LeY-overexpressing cell line, RMG-I-H, was developed previously by transfection of the α1,2-fucosyltransferase gene, a key enzyme that catalyzes the synthesis of LeY, into ovarian carcinoma-derived RMG-I cells. Our studies have shown that LeY is involved in the changes in biological behavior of RMG-I-H cells. However, the mechanism is still largely unknown. In this study, we determined the structural relationship and co-localization between LeY and TßRI/TßRII, respectively, and the potential cellular signaling mechanism was also investigated. We found that both TßRI and TßRII contain the LeY structure, and the level of LeY in TßRI and TßRII in RMG-I-H cells was significantly increased. Overexpression of LeY up-regulates the phosphorylation of ERK, Akt and down-regulates the phosphorylation of Smad2/3. In addition, the phosphorylation intensity was attenuated significantly by LeY monoantibody. These findings suggest that LeY is involved in the changes in biological behavior through TGF­ß receptors via Smad, ERK/MAPK and PI3K/Akt signaling pathways. We suggest that LeY may be an important composition of growth factor receptors and could be an attractive candidate for cancer diagnosis and treatment.

Lewis(y) antigen stimulates the growth of ovarian cancer cells via regulation of the epidermal growth factor receptor pathway.

Lewis(y) antigen is an oligosaccharide containing two fucoses, and is expressed variously in 75% of ovarian tumors, where its high expression level predicts poor prognosis. The effect and the possible mechanism of Lewis(y) on the proliferation of human ovarian cancer cells are still largely unkown. We report here that transfecting alpha1,2-FT gene into RMG-I cells increased the expression of Lewis(y) and promoted cell proliferation. In alpha1,2-FT-transfected cells, the Lewis(y) content of EGFR was increased dramatically. Tyrosine phosphorylation of EGFR was elevated. Concomitantly, tyrosine phosphorylation of Akt, ERK1/2 was also upregulated. Moreover, the expression of HER2/neu mRNA and protein, the tyrosine phosphorylation of HER2/ neu were also elveated, while the expression of p27 was significantly reduced. However, the expression of EGFR and the relative content of Lewis(y) on HER2/neu were unchanged. The above-mentioned alterations were correlated with the Lewis(y) content of EGFR and alpha1,2-FT expression in cells. In addition, the phosphorylation intensity and difference in phosphorylation intensity between cells with different expression of alpha1,2-FT were attenuated significantly by the inhibitor of EGFR tyrosine kinase and by the mono-antibody to Lewis(y). Meanwhile, the reduction in p27 and the difference in its expression among the two cell lines were also blocked by the Lewis(y) antibody. The PI3K signaling pathway was more important than the MAPK pathway in the regulation of p27 expression. These findings provide strong evidence that increased expression of Lewis(y) promotes cell proliferation through regulating the phosphorylation and expression of some molecules involved in the EGFR/PI3K-signaling pathway.

Enhancement of the adhesive and spreading potentials of ovarian carcinoma RMG-1 cells due to increased expression of integrin alpha5beta1 with the Lewis Y-structure on transfection of the alpha1,2-fucosyltransferase gene.

Le(Y) antigen is known to be associated with malignant properties including metastasis and a poor prognosis of ovarian carcinomas. To clarify the mechanisms underling these properties, we established ovarian carcinoma-derived cells exhibiting enhanced expression of Le(Y) by transfection with alpha1,2-fucosyltransferase and compared their cellular properties with those of the original cells. So the human alpha1,2-fucosyltransferase gene was transfected into ovarian carcinoma-derived RMG-1 cells, which are known to contain Le(X), a precursor of Le(Y), and RMG-1-hFUT cells exhibiting enhanced expression of Le(Y) were established by selection with anti-Le(Y) antibodies, and their adhesive and spreading potentials on fibronectin-coated plates were compared with those of RMG-1 cells. Results showed that the relative expression of Le(Y) in RMG-1-hFUT cells was about 20-fold that in RMG-1 cells, and that of integrin alpha5beta1 and an integrin-mediated signal transduction molecule, focal adhesion kinase, was also increased in RMG-1-hFUT cells. Interestingly, anti-Le(Y) antibodies were revealed to immunoprecipitate integrin alpha5beta1, indicating that its oligosaccharides are composed of Le(Y), the amounts of which was substantially elevated in RMG-1-hFUT cells. The adhesion and spreading potentials on fibronectin-coated plates of RMG-1-hFUT cells were significantly enhanced in comparison to those of RMG-1 cells, and were greatly suppressed by anti-Le(Y) antibodies, indicating that Le(Y) is involved in the integrin-fibronectin interaction. These results suggested that transfection of the alpha1,2-fucosyltransferase gene into ovarian carcinoma-derived cells brought about elevated expression of integrin alpha5beta1 with Le(Y), resulting in enhancement of the adhesion and spreading potentials of cells through the integrin-fibronection interaction, which was inhibited by anti-Le(Y) antibodies. Thus, Le(Y) in integrin alpha5beta1 was thought to be involved in the enhanced cell adhesion properties of malignant ovarian carcinomas.

[Effect of Lewis y antigen on regulating gene expression of partial drug resistance associated proteins in human ovarian cancer cell line RMG-I-H].

OBJECTIVE: To investigate the influence of Lewis y antigen on the gene expression of partial drug resistance associated proteins in human ovarian cancer cell line RMG-I-H. METHODS: RT-PCR was used to determine the gene expressions of partial drug resistance associated proteins in RMG-I-H cell line transfected with alpha1, 2-fucosyltransferases gene and RMG-I cell line, as well as in RMG-I-H treated with or without anti-Lewis y monoclonal antibody at the concentration of 10 micro/g/ml. The immunocytochemical method was used to detect the expression of P-glycoprotein (P-gp) in RMG-I and RMG-I-H cell lines. RMG-I and RMG-I-H cells were transplanted into nude mice and the expression of P-gp in the tissues was measured by immunohistochemistry. RESULTS: The mRNA expressions of protein kinase C-alpha (PKC-alpha), topoismerase I ( Topo I ), multidrug resistance-associated protein-1 (MRP-1), and MRP-2 were significantly higher in RMG-I-H cells than those in RMG-I cells (0.46 +/- 0.02 vs. 0.27 +/- 0.05, 0.82 +/- 0.08 vs. 0.52 +/- 0.04, 0.66 +/- 0.07 vs. 0.34 +/- 0.12, and 0.44 +/- 0.08 vs. 0.23 +/- 0.05; all P < 0.05). However, the mRNA expression of multi-drug resistance 1 (MDR-1) was significantly lower in RMG-I-H cells than that in RMG-I cells (0.26 +/- 0.05 vs. 0.45 +/- 0.08, P < 0.05). The P-gp level increased in RMG-I-H cells compared with that in RMG-I cells both in vivo and in vitro (P < 0.05). Expressions of MDR-1, MRP-1, MRP-2, PKC-alpha, and Topo I mRNA decreased by the time in RMG-I-H cells treated with anti-Lewis y monoclonal antibody (all P < 0.05), while mRNA expressions of those genes in the control group did not statistically change (P > 0.05). In addition, MDR-1, MRP-1, MRP-2, PKC-alpha, and Topo I mRNA expressions were significantly lower in RMG-I-H cells treated with anti-Lewis y monoclonal antibody than those in the control group at 6 hours (all P < 0.05) and the inhibition ratios were 48.55%, 77.50%, 70.18%, 45.86%, and 46.13%, respectively. CONCLUSION: The Lewis y antigen of the human ovarian cancer cell surface is closely correlated with the regulation on the gene expression of partial drug resistance associated proteins.

[Impact of alpha1,2-fucosyl transferase gene transfection on cancer-related gene expression profile of human ovarian cancer cell line RMG-1].

BACKGROUND & OBJECTIVE: The malignant biological behaviors are enhanced in human ovarian cancer cell line RMG-1 after transfection of alpha1,2-fucosyl transferase (alpha1,2-FT) gene. This study was to investigate the influence of alpha1,2-FT gene transfection on cancer-related gene expression profile of RMG-1 cells. METHODS: Gene expressing vector pcDNA3.1-HFT-H and empty vector pcDNA3.1 were transfected into RMG-1 cells to produce RMG-1-H and RMG-1-C cells separately. Gene expression profiles of these two cell lines were detected by gene chip assay. The acquired data were inquired on the GoMiner online database. RESULTS: After transfection, comparing with those in RMG-1-C cells, 88 differentially expressed genes were identified in RMG-1-H cells: 60 were up-regulated and 28 were down-regulated. These genes are involved in protein binding, nucleotide binding, cell proliferation, DNA-dependent regulation of transcription, signal transduction, protein amino acid phosphorylation, transcription, cell adhesion, and so on. CONCLUSION: The transfection of alpha1,2-FT gene causes the changes of gene expression profile in ovarian cancer RMG-1 cells.

[Transfection of alpha1, 2-fucosyltransferase gene increases the antigenic expression of Lewis y in ovarian cancer cell line RMG-I].

OBJECTIVE: To transfect human alpha1, 2-fucosyltransferase (alpha1, 2-FT) gene to ovarian cancer cell line RMG-I and investigate the antigenic expression change of Lewis y and the other related oligosaccharides. METHODS: The expression vector pcDNA3.1(-)-HFUT-H was constructed by polymerase chain reaction (PCR) to clone human alpha1, 2-FT gene coding region. The alpha1, 2-FT gene stable high-expression cell line RMG-I-H was established by transfecting pcDNA3.1(-)-HFUT-H to ovarian cell line RMG-I. The change of alpha1, 2-FT activity in the cell line before and after the tranfection was confirmed by the determination of enzymatic activity. The changes of cell lipid and glucolipid, especially the change of type II oligosaccharide, in the cell line before and after the transfection was determined by Thin-Layer Chromatography (TLC) and TLC immunostaining method, respectively. RESULTS: The H-1 antigen and Lewis y antigen were obviously increased in the cell line RMG-1-H, especially the latter one, which was 20 times higher than before, and the type I saccharide chain Lewis b was decreased significantly. The main lipid components on the cell membrane, cholesterol and phosphatides, showed no change in the cell lines before and after the transfection, and the neutral glycolipid also showed no obvious change. CONCLUSIONS: The transfection of alpha1, 2-FT gene can increase the activity of alpha1, 2-FT in the cell line RMG-I and mainly increase the expression of Lewis y antigen simultaneously. The construction of RMG-I Lewis y high expression cell line provides a cell model for further study on the relationship between Lewis y antigen and biological behaviors in the ovarian cancer.