竹井 裕二

SU6668 (TSU-68) is a small-molecule synthetic inhibitor of the angiogenic related receptor tyrosine kinases Flk-1/KDR, PDGFRbeta, and FGFR1. Using a mouse model of peritoneally disseminated ovarian cancer, we investigated whether SU6668 inhibits peritoneal dissemination and prolongs survival time. BALB/c nude mice were intraperitoneally (i.p.) inoculated with SHIN-3 (VEGF-hypersecretory) or KOC-2S (PDGF-hypersecretory) ovarian serous adenocarcinoma cells with marked peritoneal dissemination ability. From the day after i.p. inoculation of tumor cells, SU6668 was orally administered 6 times weekly at a daily dose of 100 mg/kg or 400 mg/kg. The SU6668-administered group and the vehicle-administered control group were compared for the number of tumor vascular endothelial cells, weight of peritoneally disseminated tumors, amount of ascitic fluid and survival time. As a result, these 3 parameters were significantly smaller in the SHIN-3-inoculated, SU6668-administered mice than in the control group (p = 0.03, p = 0.002, and p = 0.02, respectively). The mean survival time was significantly longer, at 58.1 +/- 11.2 days, in the SU6668-administered mice than that (34.5 +/- 8.8 days) in the control group (p = 0.002). Similarly, in the KOC-2S-inoculated mice, the oral administration of SU6668 significantly reduced these 3 parameters (p = 0.04, p = 0.04, and p = 0.03, respectively), and significantly prolonged survival (16.6 +/- 1.7 days vs. 11.0 +/- 0.7 days, p = 0.008). Thus, the oral administration of SU6668 inhibited angiogenesis and peritoneal dissemination and prolonged survival in mice with peritoneally disseminated ovarian cancer. These effects were observed with both the VEGF- and PDGF-hypersecretory cell lines. Our results suggest that molecular targeting with oral SU6668 will become a new therapeutic strategy targeting peritoneally disseminated ovarian cancer.

A Kunitz-type protease inhibitor, bikunin, is known to suppress the invasion and metastasis of cancer cells. HI8, a carboxyl-terminal domain of bikunin, is an active site of this glycoprotein. To increase its affinity for cancer cells, we constructed a chimeric gene, ATF-HI8, and investigated the anti-invasive and anti-migratory activity of ATF-HI8 on ovarian cancer cells. ATF-HI8-expressing plasmid and ATF-expressing plasmid were introduced into the highly invasive and metastatic ovarian cancer cell line HRA. The properties of the established cell line (HRA/ATF-HI8) were compared to those of the HRA/ATF and the HRA/luciferase (HRA/LUC, control) cell lines in terms of cell proliferation, invasion and migration. As a result, (i) there were no differences in cell proliferation between HRA/ATF-HI8 and HRA/LUC; (ii) the invasion and migration of HRA/ATF-HI8 cells were significantly inhibited compared to those of HRA/LUC cells; (iii) the migration, but not the invasion, of HRA/ATF cells was significantly inhibited compared to that of HRA/LUC. These results indicate that the overexpression of ATF-HI8 inhibits the invasion and migration of ovarian cancer cells without affecting cell proliferation and suggest that HI8 is involved in the anti-invasive and the anti-migratory activities, and the addition of ATF brought about the increase in the anti-migratory activity of HI8. The above findings suggest the applicability of therapeutic strategies targeting the inhibition of peritoneal invasion and dissemination of ovarian cancer by the use of the chimeric gene ATF-HI8.

Peritoneal dissemination is the major progression pathway of ovarian cancer, and its control is important for improvement of the prognosis. PTEN is a tumor suppressor gene, and is known to inhibit cancer cell growth and migration. To investigate the possibility of gene therapy using PTEN for ovarian cancer, we introduced PTEN cDNA into an ovarian cancer cell line HRA carrying wild-type PTEN, and examined the effects in vitro and in vivo. Using PTEN cDNA cloned from a human liver cDNA library, a PTEN expression vector was constructed. This vector was introduced into HRA cells by the standard calcium phosphate precipitation method, and an HRA cell line overexpressing PTEN (HRA/PTEN) was established. On the cell migration test by in vitro scratch wound healing assay, the number of migrating cells was 6.3+/-0.9 cells/mm(2) in HRA/PTEN, which was significantly smaller than that in the control (39.7+/-3.2 cells/mm(2)) (p<0.01). No significant differences were observed in the in vitro cell growth or in vivo tumor growth between HRA/PTEN and the control. The findings described above, show that enhanced expression of PTEN inhibits ovarian cancer cell migration, suggesting that gene therapy approaches using PTEN for control of peritoneal dissemination of ovarian cancer are possible.

The prognosis of cancers of various organs overexpressing thymidylate synthase (TS) has been reported to be poor. It has been suggested that the poor prognosis is partly due to a low sensitivity of TS-overexpressing tumors to TS-targeting 5-fluorouracil (5-FU). To investigate the relationship between TS expression and sensitivity to 5-FU, we used the TS-overexpressing cervical cancer cell line SKG-II/TS and SKG-I/TS that had been established by TS gene transfer. The 50% growth inhibitory concentration (IC(50)) of 5-FU for SKG-II/TS was 24 +/- 6.0 microM, which was 6 times as high as that for the control (4.0 +/- 1.1 microM), showing significantly decreased sensitivity to 5-FU (p < 0.01). The IC(50) of 5-FU for SKG-I/TS was 90 +/- 15 microM, which was over 2 times as high as that for the control (40 +/- 0.6 microM), showing significantly decreased sensitivity to 5-FU (p < 0.05). Thus, TS-overexpressing tumors have decreased sensitivity to 5-FU, which may be one of the factors that determine the prognosis of these tumors.

Interleukin-10 (IL-10) is an immunosuppressive cytokine produced by T lymphocytes and drawing attention as an inhibitor of tumor angiogenesis. In this study, we investigated antiangiogenic and tumor suppressive effects of IL-10 in ovarian cancer cells. mIL-10-expressing plasmid was transferred into two ovarian cancer cell lines, SHIN-3 [vascular endothelial growth factor (VEGF) producing] and KOC-2S (non-VEGF producing). After selection, mIL-10-expressing cells were obtained as SHIN-3/mIL-10 and KOC-2S/mIL-10. No significant differences were observed in in vitro growth properties between mIL-10-expressing cells and control (luciferase expressing) cells in either KOC-2S or SHIN-3. The angiogenic activities of mIL-10-expressing cells were measured by dorsal air sac assay, which detected the number of newly formed blood vessels within a chamber in vivo. In addition, tumor formation was evaluated by s.c. tumor transplantation, and survival was monitored after i.p. injection of ovarian cancer cells into BALB/c nude mice. Both in vivo angiogenic activity and tumor growth were significantly inhibited in SHIN-3/mIL-10 cells compared with the control. Moreover, peritoneal dissemination was inhibited, and the survival period was significantly prolonged (mean survival days > 90 versus 36). In contrast, in the case of KOC-2S cells, no significant differences were observed in any of the parameters tested. These results indicate that IL-10 has suppressive effects on angiogenesis, tumor growth, and peritoneal dissemination of VEGF-producing ovarian cancer cells. Although the mechanisms of the antiangiogenic effect of IL-10 are still unclear, the potential usefulness of IL-10-mediated gene therapy of ovarian cancer was suggested.

PROBLEM: Since transvaginal hydrolaparoscopy (THL) was introduced as the first-line procedure in the early stages of the exploration of the adnexal structures in infertile women, it has been shown that THL is a less traumatic and a more suitable outpatient procedure than diagnostic laparoscopy. This study was performed to investigate the relationships between Chlamydia trachomatis antibody titers and tubal pathology assessed using THL in infertile women. METHODS: The C. trachomatis antibody titers (IgG and IgA) were evaluated by ELISA. The posterior of the uterus and the tubo-ovarian structures were carefully observed, and tubal passage using indigocarmine was confirmed using THL. THL was carried out in 32 infertile women having C. trachomatis antibody in their sera between May 1999 and October 2001. Unilateral salpingectomy had been performed on two of the 32 patients. RESULTS: Tubal occlusion was confirmed in 20 (32.3%) of the 62 tubes, while peritubal adhesion was diagnosed in 37 (59.7%) of the 62 tubes. Using receiver operating characteristics curves, the cut-off value of C. trachomatis IgG antibody titer to predict tubal occlusion was determined to be 3.55. Tubal occlusion was observed in 16 (51.6%) of the 31 tubes in patients with the C. trachomatis IgG antibody titer of more than 3.55, which was significantly higher in four (12.9%) of the 31 tubes having the antibody titer less than 3.55 (P = 0.004). However, there was no correlation between C. trachomatis IgG antibody titer and peritubal adhesion. As for C. trachomatis IgA antibody titer, there was no correlation between antibody titer and tubal occlusion or peritubal adhesion. CONCLUSIONS: These results suggest that C. trachomatis infection is significantly associated with tubal pathology. Although the cut-off value of C. trachomatis IgG antibody titer to predict the existence of tubal occlusion was shown to be 3.55, we would suggest that THL or standard laparoscopy is performed to consider appropriate treatments in patients with past C. trachomatis infection because of the high prevalence of peritubal adhesion.

Bikunin, a Kunitz-type protease inhibitor, could potentially suppress tumor cell invasion and metastasis. Our previous study revealed that overexpression of bikunin in a human ovarian cancer cell line, HRA, resulted in a down-regulation in uPA and uPAR gene expression. For identifying the full repertoire of bikunin-regulated genes, a cDNA microarray hybridization screening was conducted using mRNA from bikunin-treated or bikunin-transfected HRA cells. A number of bikunin-regulated genes were identified, and their regulation was confirmed by Northern blot analysis. Our screen identified 11 bikunin-stimulated genes and 29 bikunin-repressed genes. The identified genes can indeed be classified into distinct subsets. These include transcriptional regulators, oncogenes/tumor suppressor genes, signaling molecules, growth/cell cycle, invasion/metastasis, cytokines, apoptosis, ion channels, extracellular matrix proteins, as well as some proteases. This screen identified suppression of several genes such as CDC-like kinase, LIM domain binding, Ets domain transcription factor, Rho GTPase-activating protein, tyrosine phosphorylation-regulated kinase, hyaluronan-binding protein, matriptase, and pregnancy-associated plasma protein-A (PAPP-A), which have previously been implicated in enhancing tumor promotion. Northern blot analysis confirmed that several genes including matriptase and PAPP-A were down-regulated by bikunin by approximately 9-fold. Further, genetic inhibition of matriptase or PAPP-A could lead to diminished invasion. These results show that bikunin alters the pattern of gene expression in HRA cells leading to a block in cell invasion.

Bikunin (bik), a Kunitz-type protease inhibitor, also known as urinary trypsin inhibitor, is proposed as a main participant in the inhibition of tumor cell invasion and metastasis, possibly through the direct inhibition of cell-associated plasmin activity and suppression of urokinase-type plasminogen activator (uPA) mRNA expression. In the present study, we transfected the human ovarian carcinoma cell line HRA, highly invasive cells, with an expression vector harboring a cDNA encoding for human bik. Our study was designed to investigate the effect of bik overexpression and changes in tumor cell phenotype and invasiveness in the stably transfected clones. Bik gene transfection of HRA gave the following results: 1) transfection of HRA with the bik cDNA resulted in 5 variants stably expressing functional bik; 2) bik(+) clones exhibited a significantly reduced uPA mRNA expression as compared to the parental cells; 3) bikunin negatively regulates the ERK1/2 activity; 4) secretion-blocking treatments of bik(+) clones abrogated bik-mediated suppression of ERK1/2 activation and uPA expression; 5) the regulation of invasion seen in the HRA cells is mainly mediated by the uPA-plasmin-MMP-2 system; 6) transfection of HRA with the bik gene significantly reduced invasion, but not proliferation, adhesion, or migration relative to the parental cells; and 7) animals with bik(+) clones induced reduced peritoneal dissemination and long term survival. We conclude that transfection of HRA cells with the bik cDNA constitutively suppresses ERK1/2 activation, which results in inhibition of uPA expression and subsequently reduces dissemination of bik(+) clones.

The aim of this study was clarification of the feasibility, effects, and adverse events of combination chemotherapy with paclitaxel and carboplatin in Japanese women with epithelial ovarian cancer. In patients with stage Ic to IV epithelial ovarian cancer, primary cytoreductive surgery was performed. Paclitaxel (175 mg/m(2)) was intravenously infused for 3 h. Subsequently, carboplatin was infused, with an area under the plasma concentration-time curve of 5. Ninety-one patients were enrolled in this study. The mean dose of paclitaxel at the sixth course was 161 mg/m(2). Of 51 patients, a complete response was observed in 19 patients (37%), and a partial response in 23 patients (45%). The response rate for clear cell adenocarcinoma was 25%. With regard to adverse events, grade 4 granulopenia was observed in 80% of patients, suggesting dose-limiting toxicity. However, none of the patients developed serious infection. With regard to non-hematological toxicity, grade 2 or 3 alopecia, arythralgia/myalgia, and peripheral neurotoxicity were noted in 97, 29, and 20% of the patients, respectively. Although hematological toxicity was relatively marked, this regimen can be applied in Japanese women.

We evaluated microsatellite instability (MSI) in primary lesions and lymph node metastatic lesions in 66 patients with endometrial carcinoma (FIGO stage IIIC) accompanied by lymph node metastasis. DNA was extracted from paraffin-embedded tissue of both the primary and lymph node metastatic lesions of endometrial carcinoma, and MSI was evaluated using microsatellite markers at five loci. Microsatellite instability was positive in the primary lesion in 27 patients (41%). All patients with MSI-positive primary lesions also showed MSI-positive in lymph node metastatic lesions. Of the other 39 patients with MSI-negative primary lesions, 4 showed MSI-positive in lymph node metastatic lesions. As the result of individual identification by polymerase chain reaction (PCR) using short tandem repeat loci in these 4 patients, PCR profiles of primary and metastatic lesions matched with those of normal controls in all 4 patients. Therefore, it was confirmed that both primary and metastatic lesions developed from the same individual. These results suggest that MSI is also involved in lymph node metastasis in the development and/or progression of endometrial carcinoma in some patients.