Nobuhiko Moniwa

Risk of developing ovarian cancer among women with ovarian endometrioma: a cohort study in Shizuoka, Japan

Although some studies have indicated that endometriosis may increase the risk of developing ovarian cancer, there are no data from epidemiologic studies in Japan. We prospectively analyzed all cases of ovarian endometrioma enrolled in the prefecture-wide Shizuoka Cohort Study on Endometriosis and Ovarian Cancer Programme, which was initiated in 1985. To evaluate the risk of ovarian cancer by time periods subsequent to ovarian endometrioma diagnosis, a cohort of 6,398 women with a clinically documented ovarian endometrioma in Shizuoka between 1985 and 1995 was identified from the Shizuoka Cancer Registry (SCR), with follow-up through 2002. Ovarian cancer incidence among cohort members was ascertained by linkage to the SCR using a unique person-identification number. Standardized incidence ratios (SIR) and their 95% confidence intervals (CI) were computed by a use of prefecture-wide rates of ovarian cancer, adjusted for age and calendar year. During follow-up of up to 17 years of the ovarian endometrioma cohort, 46 incident ovarian cancers were identified, yielding that the ovarian cancer risk was elevated significantly among patients with ovarian endometrioma (SIR = 8.95, 95% CI = 4.12–15.3). The SIR did not increase with increasing follow-up duration. The risk increased with increasing age at ovarian endometrioma diagnosis, with a SIR equal to 13.2 (95% CI = 6.90–20.9) in women above 50 years of age. Our findings for the first time support the hypothesis that ovarian endometrioma increases the subsequent risk of developing ovarian cancer in Shizuoka, Japan

Effects of membrane-associated cathepsin B on the activation of receptor-bound prourokinase and subsequent invasion of reconstituted basement membranes

The present study was undertaken to assess the role of membrane-associated cathepsin B as an activator of receptor-bound single-chain urokinase-type plasminogen activator (pro-uPA) and to determine the importance of receptor-bound uPA activity in the destruction of extracellular matrix by tumor cells with subsequent invasion through basement membranes. Ovarian cancer HOC-I cells express pro-uPA/HMW-uPA and cathepsin B on their surface. uPAs are bound to a specific surface receptor, about 30% of which is saturated. 60% of the receptor-bound uPA is pro-uPA. No reduction in the specific binding of biotinylated DFP-HMW-uPA was observed when cells were cultivated in the presence of E-64, a cysteine proteinase inhibitor, for 24 h. Inhibition of cell-surface cathepsin B activity was associated with a decrease in cell-bound uPA activity to undetectable levels, and > 95% of the membrane-associated uPA was pro-uPA in cells cultivated with E-64. This suggested that receptor-bound pro-uPA cannot be converted to HMW-uPA in the absence of enzymatically-active cathepsin B. The significance of the expression of cell-surface uPA activity regarding invasive potential was examined in an in-vitro Matrigel invasion assay. Decreased cell-surface uPA activity was associated with a decrease in invasive potential. These data support our hypothesis that membrane-associated cathepsin B may be important for the conversion of pro-uPA to HMW-uPA and that receptor-bound uPA activity constitutes an efficient mechanism which contributes to tumor cell invasion. As HOC-I cells produce both uPA and cathepsin B, the implications of tumor-cell-derived pro-uPA activation by cellular proteinase cathepsin B should be considered.

Increased cell-surface urokinase in advanced ovarian cancer.

Urokinase‐type plasminogen activator (uPA), uPA receptors, and cathepsin B were quantitatcd by using an immunological method, enzyme‐linked immunosorbent assay, and amidolytic activity assays in 15 malignant and 10 benign epithelial ovarian tumors. The levels of uPA and uPA receptors, as well as cathepsin B, were found to be higher in membrane preparations obtained from malignant tumors than in those obtained from benign tumors. Acid‐treated membranes acquired the ability to bind uPA, indicating that uPA is bound to a specific surface receptor that is not completely saturated. Levels of single‐chain uPA (pro‐uPA) and high‐molecular‐weight uPA in membrane preparations were measured by immunoadsorbent‐amidolytic assay. The finding of a significant increase in amidolytic activity following activation of uPAs by plasmin suggested that less than half (30–40%) of all membrane immunoreactive uPAs is present in the enzymatically inactive pro‐uPA form. In the membranes of malignant tumors, levels of uPA receptor and cathepsin B did not vary with stage of disease. On the other hand, we found that the level of receptor‐bound uPA antigen/activity was significantly increased in advanced malignant tumors. Receptor‐bound uPA may play an important role in determining invasive potential of tumor cells. Since ovarian cancer cells produce both pro‐uPA and cathepsin B, the possibility of activation of tumor cell‐derived pro‐uPA by cellular protease cathepsin B must be considered.

CHARACTERIZATION OF CA 125 ANTIGEN IDENTIFIED BY MONOCLONAL ANTIBODIES THAT RECOGNIZE DIFFERENT EPITOPES

The present study was undertaken to characterize the antigenic determinant of the CA 125 macromolecules recognized by newly developed monoclonal antibodies (M 11, 130-22, 145-9, 602-1, and 602-6), examine their relationship among the epitopes recognized by these antibodies, and develop a series of enzyme-linked immunosorbent assays (ELISAs) in which various combinations of antibodies are used in a double-determinant sandwich mode. The antigenic determinants of CA 125 were characterized by several methods including competitive ELISA and immunoblotting. These antibodies, as well as OC 125, reacted with ovarian cancer (HOC-I) cell extract in a dose-dependent manner. Purified CA 125 antigen with a molecular mass of less than 200 kDa (CA 125 < 200 kDa) had a significant inhibitory effect on the reaction between the cancer cell extract and all these antibodies. The reactivity of M 11, 130-22, 145-9, 602-1, and 602-6 to the cancer cell extract was not significantly inhibited by purified CA 125 > or = 200 kDa, whereas the reactivity of OC 125 was completely inhibited by CA 125 > or = 200 kDa. The antigenic determinants of M 11, 145-9, 602-6, 130-22, and 602-1 were closely related to each other, in this order; whereas OC 125 recognized a different epitope on a structurally identical molecule. The use of these monoclonal antibodies in combination with each other may result in the development of a more specific and sensitive assay for CA 125.

The role of activated protein C (APC) in fibrinolysis of human placenta

Summary Suppression of the fibrinolytic activity plays an impotant role in the prevention of hemorrhage during pregnancy and labor. A hypofibrinolytic and hypercoagulable state may be established in the placenta during pregnancy. However, little infarcition is present in the normal placenta. This evidence demonstrates that the placenta maintains a fibrinolytic activity in spite of a hypercoagulation state. We studied the role of APC (activated protein C) on fibrinolysis in the placenta. (1) APC-PAI-1 (plasminogen activator inhibitor type-1) complexes were demonstrated in serum-free culture medium when human umbilical vein endothelial cells (HUVEC) were incubated with APC, indicating that PAI-1 was dissociated from receptor-bound uPA (urokinase type plasminogen activator) on the cell surface of HUVEC. This was also confirmed by enzyme-linked immunosorbent assay (ELISA), (2) APC antigen is located on the syncytiotrophoblast in first trimester placenta by immunohistochemistry. Taken together, these results suggest that APC could possibly play a significant role in fibrinolytic activity during early stages of gestation.