Hideki Kuroda

Expression of vascular endothelial growth factor (VEGF) during folliculogenesis and corpus luteum formation in the human ovary

Vascular endothelial growth factor (VEGF) has been suggested to be involved in angiogenesis and microvascular hyperpermeability. We examined immunohistochemically the expression of VEGF in the granulosa and theca cells, along with that of proliferating cell nuclear antigen (PCNA), in the vascular endothelium during the course of follicular development and corpora lutea formation in human ovaries. The immunolocalization of VEGF in these cells was compared with that of another putative angiogenic factor, basic fibroblast growth factor (bFGF). The granulosa cells in the primordial and primary follicles were VEGF negative, but at the preantral stage, the granulosa cells showed weakly positive immunostaining for VEGF. However, the VEGF immunostaining in the granulosa cells was weak throughout the folliculogenesis. In contrast, the theca interna cells of developing follicles showed strong staining for VEGF, which was well correlated with the PCNA positivity in the vascular endothelial cells in the thecal layer. In the atretic follicles, the granulosa and theca cells were VEGF negative. In the corpora lutea, VEGF was strongly expressed in both granulosa and theca lutein cells in the early luteal phase when the PCNA positivity in the endothelium increased, but the VEGF staining in these cells became weak in the mid- and late luteal phases. Accordingly, the PCNA positivity in the vascular endothelium was well correlated with the expression of VEGF in the theca cells during follicular development and atresia, and that in the granulosa and theca lutein cells in corpora lutea formation and regression. In addition, the immunolocalization of VEGF was different from that of bFGF.

Review: Gonadotropins and Development of Ovarian Cancer

An epidemiological correlation between infertility therapy and ovarian cancer development has been reported in 1992; consequently, the possible role of gonadotropins in ovarian carcinogenesis has received much attention. Here, we review the effect of gonadotropins on epithelial ovarian carcinoma and ovarian surface epithelium (OSE), which is the histogenetic origin of carcinomas. Recent studies have demonstrated that gonadotropin receptors are expressed in OSE and in approximately half of the ovarian carcinomas. Gonadotropins have also been reported to stimulate cell proliferation and to inhibit apoptosis in OSE and ovarian cancer cells. These data suggest that gonadotropins play an important role in the development, progression, and/or chemoresistance of ovarian carcinomas. Hormonal therapy against gonadotropins may be applicable for patients with ovarian carcinoma.

Messenger ribonucleic acid expression of LH/hCG receptor gene in human ovarian carcinomas

The mRNA expression of luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptors was analysed by the RT-nested PCR method in five normal ovarian tissues, 62 ovarian tumours (5 benign, 7 borderline and 43 malignant epithelial tumours, 3 sex cord-stromal tumours and 4 germ cell tumours) and in 2 ovarian cancer cell lines. In normal ovaries, two cDNA fragments of different sizes were detected using primers designed to amplify a region including exon 9. Sequencing revealed that the larger fragment was derived from a full-length receptor, while the smaller fragment was a splice variant lacking exon 9. In ovarian tumours, the larger fragment of LH/hCG receptors was detected in 40% of the epithelial ovarian carcinomas, none of the germ cell tumours, all of the sex cord-stromal tumours and one of the 2 ovarian cancer cell lines. Immunohistochemistry confirmed the localisation of LH/hCG receptor protein in the tumour cells which correlated with mRNA expression. Patients with full-length LH/hCG receptors in carcinomas showed a better prognosis compared with those without the receptors.

Expression of heat shock proteins HSP70 and HSP90 in endometrial carcinomas: Correlation with clinicopathology, sex steroid receptor status, and p53 protein expression

It has been suggested that heat shock proteins HSP70 and HSP90 are involved in the functional modulation of sex steroid receptors and are expressed in normal endometrium. However, little is known about the expression of HSP70 and HSP90 in endometrial carcinomas.

Immunohistochemical localization of basic fibroblast growth factor (bFGF) during folliculogenesis in the human ovary

Basic fibroblast growth factor (bFGF) has been suggested to be one of the intraovarian regulators of ovarian folliculogenesis, but its localization in the human ovary remains to be determined. We examined the immunohistochemical reactivity for bFGF in the course of follicular development and corpora lutea formation in the human ovary. Pregranulosa cells in the primordial follicle were negative, but at the preantral stage both granulosa and theca cells showed weakly positive immunostaining for bFGF. In the antral follicles, both granulosa and theca interna cells showed stronger staining for bFGF with the increase in follicular diameter. In atretic follicles at various stages, granulosa cells were negative or weakly positive for bFGF, whereas luteinized theca cells showed strong immunoreactivity. In the corpora lutea during the early luteal phase, granulosa lutein cells were strongly positive for bFGF but in the late luteal phase became immunonegative. On the other hand, bFGF staining in theca lutein cells was strong throughout the course of corpora lutea formation and regression. These findings suggest that bFGF is localized not only in granulosa cells but also in theca cells, and in the latter, bFGF immunoreactivity is associated with luteinization.

Human ovarian surface epithelial (OSE) cells express LH/hCG receptors, and hCG inhibits apoptosis of OSE cells via up-regulation of insulin-like growth factor-1

Gonadotropins including luteinizing hormone (LH) or human chorionic gonadotropin (hCG) have been implicated as playing an important role in the development of epithelial ovarian carcinomas, most of which are believed to originate from the ovarian surface epithelium (OSE). To address this issue, we examined the expression of LH/hCG receptors and the influence of hCG on cell proliferation and on the apoptosis of cultured human OSE cells. RT‐PCR and binding assay revealed that OSE cells express the LH/hCG receptor mRNA and have specific binding activity for hCG. Treatment with hCG stimulated the proliferation of OSE cells in a dose‐dependent manner. In addition, hCG treatment inhibited the apoptosis of OSE cells induced by serum deprivation. Among the apoptosis‐related genes, hCG treatment did not change the mRNA levels of bcl‐2, bax and IGF‐1 receptor but significantly increased that of IGF‐1. Treatment with IGF‐1 alone also suppressed the apoptosis of OSE cells, and treatment by hCG along with neutralization antibody against IGF‐1 receptor reversed the anti‐apoptotic effect of hCG. Accordingly, LH/hCG signaling followed by up‐regulation of IGF‐1 is involved in the inhibition of apoptosis of OSE cells, the possible histogenetic origin of epithelial ovarian carcinomas.

MRI of adenomyotic cyst of the uterus

The radiologic and pathologic features of three cases of adenomyotic cysts are presented. Two cases were subserosal and one was intramyometrial. All three cases had cystic spaces filled with hyperintense fluid on T1-weighted images, which were surrounded by hypointense tissue on T2-weighted images.

Human chorionic gonadotropin (hCG) inhibits cisplatin‐induced apoptosis in ovarian cancer cells: Possible role of up‐regulation of insulin‐like growth factor‐1 by hCG

Gonadotropins have been suggested to play a role in the development or progression of ovarian cancer, and we have previously reported the expression of luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor in 40% of epithelial ovarian carcinomas. To examine the biological effect of LH/hCG on ovarian cancer cells, apoptosis induced by cisplatin with or without hCG treatment was investigated in 2 ovarian cancer cell lines, OVCAR‐3 and SK‐OV‐3. Stimulation of cell proliferation by hCG was also studied. In addition, to analyze further the mechanism of hCG signaling involved in apoptosis‐inhibition, we examined the expression of LH/hCG receptors and the regulation by hCG for apoptosis‐inhibitory pathways, such as the bcl‐2/bax system and the insulin‐like growth factor‐1 (IGF‐1)/IGF‐1 receptor (IGFR) system. hCG did not increase cell proliferation in either cell line. However, hCG treatment suppressed cisplatin‐induced apoptosis by 58% in the OVCAR‐3 cells, as shown by immunofluorescent staining and quantitation of DNA fragmentation. LH/hCG receptor mRNA was expressed only in OVCAR‐3, and no apoptosis‐inhibitory effect of hCG was observed in the SK‐OV‐3 cells that did not express the receptor. In the OVCAR‐3 cells, hCG significantly increased mRNA expression of IGF‐1, but did not change mRNA levels of bcl‐2/bax. Our findings suggest that LH/hCG influences the chemosensitivity of ovarian cancer cells through an apoptosis‐inhibitory signal possibly via up‐regulation of IGF‐1 expression. Int. J. Cancer 76:571–578, 1998.© 1998 Wiley‐Liss, Inc.

Combination effect of adenovirus-mediated pro-apoptotic bax gene transfer with cisplatin or paclitaxel treatment in ovarian cancer cell lines.

To develop a novel therapeutic strategy for ovarian cancer, we constructed a recombinant adenovirus which highly expresses pro-apoptotic Bax protein and examined its therapeutic effect on a series of ovarian cancer cell lines: A2780, A2780/cDDP, OVCAR-3 and SK-OV-3. A recombinant adenovirus carrying the Bax-alpha gene (AxCALNKYbax) induced high expression of the Bax-alpha protein in all the cell lines. The cytotoxic effect of Bax was observed in three ovarian cancer cell lines: the per cent reduction in the number of cells was 40.0% for cisplatin-sensitive A2780, 50.0% for cisplatin-resistant A2780/cDDP, and 64.8% for marginally cisplatin-resistant OVCAR-3. In contrast, it was only 12.3% for cisplatin-resistant SK-OV-3. Cisplatin-resistant A2780/cDDP had a p53 mutation and exhibited attenuated Bax induction after cisplatin treatment, which may explain why supplementation of Bax was effective in this chemoresistant ovarian cancer. Combination with cisplatin or paclitaxel enhanced the cytotoxic effect of Bax induction in all but one cell line including cisplatin-resistant A2780/cDDP. It appears that adenovirus-mediated Bax induction, with or without combination with conventional chemotherapy, useful strategy for the treatment of ovarian cancer.

LH/hCG action and development of ovarian cancer—A short review on biological and clinical/epidemiological aspects

A link between infertility therapy, especially ovulation induction therapy using gonadotropins, and the development of ovarian cancer has long been an issue of debate since an epidemiological report supporting the possibility appeared in 1992. A number of clinical/epidemiological and biological studies, including a few that we conducted, have revealed various facts regarding this issue. The aim of this short review was to summarize the last 10 years findings and to address the implications of the debates on this issue.