IGHG1 promotes motility likely through epithelial-mesenchymal transition in ovarian cancer

Objective： Ovarian cancer（OC） is one of the leading causes of death for female cancer patients. COC166-9 is an OC-specific monoclonal antibody and we have identified immunoglobulin γ-1 heavy chain constant region（IGHG1） as its antigen. We explore the function of IGHG1 in proliferation, apoptosis and motility of OC cells further in this research.Methods： IGHG1 expression in OC specimens was detected through immunohistochemistry. Real-time quantitative polymerase chain reaction（RT-q PCR） or western blotting assay was used to test IGHG1 expression in OC cells. Viability of OC cells was tested by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide（MTT）assay. Flow cytometry or western blotting assay was used to detect cell cycle and apoptosis. Cellular motility was analyzed by using transwell assay and the markers of epithelial-mesenchymal transition（EMT） were tested through immunoblots.Results： Although it exerts negligible effect on the viability and apoptosis of OC cells, IGHG1 could promote migration and invasion of malignant cells in vitro. Mechanistically, IGHG1 increases the expression of N-cadherin and Vimentin while decreases E-cadherin expression. Additionally, IGHG1 expression in OC specimens is higher relative to the paired normal counterparts. Further analysis demonstrates that the increased IGHG1 expression correlates positively with the lymph node metastasis of OC.Conclusions： IGHG1 promotes the motility of OC cells likely through executing the EMT program. Increased IGHG1 expression in OC specimens is associated with the lymph node metastasis.

Evaluation of COC183B2 antibody targeting ovarian cancer by near-infrared fluorescence imaging

Objective: To evaluate the imaging potential of a novel near-infrared(NIR) probe conjugated to COC183 B2 monoclonal antibodies(MAb) in ovarian cancer(OC).Methods: The expression of OC183 B2 antigen in OC was determined by immunohistochemical(IHC) staining using tissue microarrays with the H-score system and immunofluorescence(IF) staining of tumor cell lines.Imaging probes with the NIR fluorescent dye cyanine 7(Cy7) conjugated to COC183 B2 Mab were chemically engineered. OC183 B2-positive human OC cells(SKOV3-Luc) were injected subcutaneously into BALB/c nude mice. Bioluminescent imaging(BLI) was performed to detect tumor location and growth. COC183 B2-Cy7 at 1.1,3.3, 10, or 30 μg were used for in vivo fluorescence imaging, and phosphate-buffered saline(PBS), free Cy7 dye and mouse isotype immunoglobulin G(IgG)-Cy7(delivered at the same doses as COC183 B2-Cy7) were used as controls.Results: The expression of OC183 B2 with a high H-score was more prevalent in OC tissue than fallopian tube(FT) tissue. Among 417 OC patients, the expression of OC183 B2 was significantly correlated with the histological subtype, histological grade, residual tumor size, relapse state and survival status. IF staining demonstrated that COC183 B2 specifically expressed in SKOV3 cells but not HeLa cells. In vivo NIR fluorescence imaging indicated that COC183 B2-Cy7 was mainly distributed in the xenograft and liver with optimal tumor-to-background(T/B)ratios in the xenograft at 30 μg dose. The highest fluorescent signals in the tumor were observed at 96 h postinjection(hpi). Ex vivo fluorescence imaging revealed the fluorescent signals mainly from the tumor and liver. IHC analysis confirmed that xenografts were OC183 B2 positive.Conclusions: COC183 B2 is a good candidate for NIR fluorescence imaging and imaging-guided surgery in OC.