The objective of the present study was to identify human epididymis protein 4 (HE4) interacting proteins and explore the mechanisms underlying their effect on ovarian cancer cell invasion and metastasis. HE4 interacting proteins were identified by mass spectrometry and validated by co-immunoprecipitation and pull-down assays. The scratch test, the Transwell assay and animal experiments were used to assess the invasive and metastatic abilities of ovarian cancer cells before and after transfection and HE4 protein treatment. HE4 and annexin II protein expression in epithelial ovarian tissues was detected by immunohistochemistry, and the relation between their expression levels was examined. Annexin II was identified as an HE4 interacting protein. HE4 and annexin II binding interaction promoted ovarian cancer cell invasion and metastasis. HE4 and annexin II expression levels were significantly higher in malignant epithelial ovarian tissues than in benign and normal epithelial ovarian tissues, and they were higher in tissues with lymph node metastases than in those without. HE4 gene interference downregulated the expression of MAPK and the FOCAL adhesion signaling pathway-associated molecules MKNK2 and LAMB2, and HE4 protein supplementation reversed this effect. The binding interaction between HE4 and annexin II activates the MAPK and FOCAL adhesion signaling pathways, promoting ovarian cancer cell invasion and metastasis.

The RGS (regulator of G protein signaling) gene family, which includes negative regulators of G protein-coupled receptors, comprises important drug targets for malignant tumors. It is thus of great significance to explore the value of RGS family genes for diagnostic and prognostic prediction in ovarian cancer. The RNA-seq, immunophenotype, and stem cell index data of pan-cancer, The Cancer Genome Atlas (TCGA) data, and GTEx data of ovarian cancer were downloaded from the UCSC Xena database. In the pan-cancer database, the expression level of RGS1, RGS18, RGS19, and RGS13 was positively correlated with stromal and immune cell scores. Cancer patients with high RGS18 expression were more sensitive to cyclophosphamide and nelarabine, whereas those with high RGS19 expression were more sensitive to cladribine and nelarabine. The relationship between RGS family gene expression and overall survival (OS) and progression-free survival (PFS) of ovarian cancer patients was analyzed using the KM-plotter database, RGS17, RGS16, RGS1, and RGS8 could be used as diagnostic biomarkers of the immune subtype of ovarian cancer, and RGS10 and RGS16 could be used as biomarkers to predict the clinical stage of this disease. Further, Lasso cox analysis identified a five-gene risk score (RGS11, RGS10, RGS13, RGS4, and RGS3). Multivariate COX analysis showed that the risk score was an independent prognostic factor for patients with ovarian cancer. Immunohistochemistry and the HPA protein database confirmed that the five-gene signature is overexpressed in ovarian cancer. GSEA showed that it is mainly involved in the ECM-receptor interaction, TGF-beta signaling pathway, Wnt signaling pathway, and chemokine signaling pathway, which promote the occurrence and development of ovarian cancer. The prediction model of ovarian cancer constructed using RGS family genes is of great significance for clinical decision making and the personalized treatment of patients with ovarian cancer.

Ovarian cancer is one of the most common malignant tumors of the female reproductive system, which seriously threatens the health of patients. It is of great significance to identify biomarkers to improve the clinical status of ovarian cancer patients. Methylation, RNA- sequencing, Copy number variation (CNV), mutation and clinical characteristics of ovarian cancer and control samples were downloaded from The Cancer Genome Atlas database (TCGA). The "iClusterPlus". R package was used to cluster the molecular subtypes. The copy number variation of the entire lncRNA genome was analyzed using GISTIC. The prognosis-associated lncRNA related to CNV was screened as potential targets for ovarian cancer. Six molecular subtypes were identified based on multi-omics analysis and DElncRNAs are significantly enriched in specific molecular subtypes. The deletion or amplification of lncRNA copy number affects the occurrence and development of ovarian cancer to some extent. Three prognostic-associated lncRNA including LOC101927151, LINC00861 and LEMD1-AS1 were selected. These lncRNAs can be used as biomarkers to predict survival in patients with ovarian cancer. The accuracy of results were verified using the Gene Expression Omnibus (GEO) dataset. Based on genome-wide copy number variation, prognostic-associated lncRNAs were identified as new biomolecular markers for ovarian cancer.

Background: Lewis y antigen is difucosylated oligosaccharide and is carried by glycoconjugates at cell surface. Elevated expression of Lewis y has been found in 75% of ovarian tumor, and the high expression level is correlated to the tumor's pathological staging and prognosis. This study was to investigate the effect and the possible mechanism of Lewis y on the proliferation of human ovarian cancer cells.Methods: We constructed a plasmid encoding α1,2-fucosyltransferase (α1,2-FT) gene and then transfected it into ovarian carcinoma-derived RMG-I cells with lowest Lewis y antigen expression level. Effect of Lewis y on cell proliferation was assessed after transfection. Changes in cell survival and signal transduction were evaluated after α-L-fucosidase, anti-Lewis y antibody and phosphatidylinositol 3-kinase (PI3K) inhibitor treatment.Results: Our results showed that the levels of α1,2-FT gene and Lewis y increased significantly after transfection. The cell proliferation of ovarian carcinoma-derived RMG-I cells sped up as the Lewis y antigen was increased. Both of α-L-fucosidase and anti-Lewis y antibody inhibited the cell proliferation. The phosphorylation level of Akt was apparently elevated in Lewis y-overexpressing cells and the inhibitor of PI3K, LY294002, dramatically inhibited the growth of Lewis y-overexpressing cells. In addition, the phosphorylation intensity and difference in phosphorylation intensity between cells with different expression of α1,2-FT were attenuated significantly by the monoantibody to Lewis y and by the PI3K inhibitor LY294002.Conclusions: Increased expression of Lewis y antigen plays an important role in promoting cell proliferation through activating PI3K/Akt signaling pathway in ovarian carcinoma-derived RMG-I cells. Inhibition of Lewis y expression may provide a new therapeutic approach for Lewis y positive ovarian cancer.

Overexpression of HE4 (human epididymis protein 4) enhances proliferation, invasion and metastasis of ovarian cancer