Motoko Sakayori

A monoclonal antibody (MSN-1) against a newly established uterine endometrial cancer cell line (SNG-II) and its application to immunohistochemistry and flow cytometry

To determine a phenotypic difference between normal endometrium and endometrial adenocarcinoma, a new monoclonal antibody (MSN-1) was produced by immunizing a new endometrial cancer cell line (SNG-II), which was established in 1981 from a 43-year-old Japanese woman with stage II uterine endometrial cancer. MSN-1 recognized the Lewis-b carbohydrate moiety on the cell surface glycolipid and seldom reacted immunohistochemically with normal endometrium but with about 90% of endometrial cancer cases. By application of MSN-1 to flow cytometry, the possibility of differentiating endometrial normal cells from cancer cells was demonstrated.

HMMC-1 A Humanized Monoclonal Antibody With Therapeutic Potential Against Müllerian Duct-Related Carcinomas

Purpose: The purpose of this research was to generate a human monoclonal antibody specific to gynecological cancers and to evaluate such an antibody as therapy for gynecological cancers. Experimental Design: Transchromosomal KM mice were immunized with the human uterine endometrial cancer cell line SNG-S. Hybridomas were constructed between spleen cells from KM mice and mouse myeloma cells. Reactivity of the antibody was evaluated by immunohistochemistry of pathological specimens of gynecological cancers. Cytotoxicity of HMMC-1 against SNG-S cells was tested by in vitro cytotoxicity assays. The epitope of HMMC-1 was determined by transfection with a panel of glycosyltransferase cDNAs and by inhibition assays with chemically synthesized oligosaccharides. Results: HMMC-1 is a human IgM monoclonal antibody that reacts positively with müllerian duct-related carcinomas with positive rates of 54.6% against uterine endometrial adenocarcinoma, 76.9% against uterine cervical adenocarcinoma, and 75.0% against epithelial ovarian cancer. HMMC-1 does not react with normal endometrium at proliferative or secretory phases, normal uterine cervix, or normal and malignant tissue from other organs, whereas it reacts weakly with the epithelium of the gall bladder and the collecting duct of the kidney. HMMC-1 exhibits antigen-dependent and complement-mediated cytotoxicity. Upon cotransfection with cDNAs encoding two glycosyltransferases required for fucosylated extended core 1 O-glycan, mammalian cells express HMMC-1 antigen. Finally, binding of HMMC-1 to SNG-S cells is inhibited by synthetic Fucα1→2Galβ1→4GlcNAcβ1→3Galβ1→3GalNAcα1-octyl. Conclusions: These results indicate that HMMC-1 specifically recognizes a novel O-glycan structure. The unique specificity and cytotoxicity of HMMC-1 strongly suggest a therapeutic potential of this antibody.

Enzymatic basis for the accumulation of Lewisb antigen in uterine endometrial cancer

In order to clarify the mechanism of the abnormal expression of Lewisb antigen, which was specific for uterine endometrial cancer tissue, the activities of α1→2fucosyltransferase, α1→3fucosyltransferase, and α1→4fucosyltransferase in normal endometrial tissues and uterine endometrial cancer tissues were determined. Further, an immunocytochemical study of the expression of blood group‐related carbohydrate antigens in 6 cultured cell lines derived from various gynecologic malignant tumors was performed and the α1→2fucosyltransferase, α1→3fucosyltransferase, and α1→4fucosyltransferase activities of these cell lines were determined. Compared with normal endometrium, uterine endometrial cancer tissues showed significantly higher values of α1→2fucosyltransferase, α1→3fucosyltransferase, and α1→4fucosyltransferase activities. The specifically strong expression of type I carbohydrate chains, particularly the Lewisb antigen, was recognized in cultured cell lines derived from uterine endometrial cancer. Compared with those cell lines derived from uterine cervical cancer and ovarian cancer, the cultured cell lines derived from uterine endometrial cancer showed higher activities of α1→2fucosyltransferase and α1→4fucosyltransferase, which are enzymes related to the synthesis of Lewisb antigen. The cell lines derived from uterine endometrial cancer showed specifically high values of α1→4fucosyltransferase activity. These results suggest that the α1→2fucosyltransferase and α1→4fucosyltransferase activities, especially the α1→4fucosyltransferase activity, contribute to the abnormal expression of the Lewisb antigen in uterine endometrial cancer.

Characteristic alteration in the concentration of IV 3NeuAc α-nLc4Cer in the villi of human placenta during the gestational period

A study on the ganglioside composition in the villi isolated from human placenta at various gestational periods was carried out by conventional procedures including thin-layer chromatography (TLC), TLC-immunostaining, negative ion fast-atom bombardment mass spectrometry (FABMS) and exoglycosidase treatment. The major gangliosides in the villi were II3 NeuAc-LacCer (GM3) and IV3NeuAc alpha-nLc4Cer, comprising 60-70% of the total gangliosides. The concentration of IV3NeuAc alpha-nLc4Cer per gram dry weight of tissue in the villi was found to be gradually decreased from the early to the late gestational period and the molecule with 2-hydroxy fatty acids was undetectable after 20 weeks of the gestational period. However, no significant correlation between the concentration of GM3 and the gestational periods was observed. Thus the characteristic alteration in the concentration of IV3NauAc alpha-nLc4Cer in the villi might be related to various functions of human placental villi during the gestational period.

Effect of Gelonin Immunoconjugate with Monoclonal Antibody MSN-1 to Endometrial Adenocarcinoma on Antigen-producing Tumor Cells in vivo

Missile therapy, which destroys cancer cells specifically, has been advocated as an effective modality for the treatment of carcinoma. We have developed an immunoconjugate consisting of the monoclonal antibody MSN‐1 (IgM), which reacts strongly with endometrial adenocarcinomas, combined with a plant hemitoxin named gelonin via a disulfide bond using N‐succinimidyl‐3‐(2‐pyridyldithio)propionate and 2‐iminothiolane, and examined its selective cytotoxicity in athymic mice. The reductions in resected weights of target tumor cells, at the local site of MSN‐1‐gelonin immunoconjugate treatment, were 96% with local administration and 75% with caudal vein administration, as compared with the untreated group. There was no weight loss in treated mice. Our results suggest that this MSN‐1‐gelonin immunoconjugate has potential clinical applications in the treatment of endometrial adenocarcinomas.