No abstract

We conducted the present study to determine the chemoresistance mechanisms in clear cell carcinoma of the ovary (CCC). Five human CCC cell lines (HAC-2, RMG-I, RMG-II, KK, and KOC7c) were used in this study. The sensitivity of the cells to the anticancer agents was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and we assessed drug sensitivity by calculating assay area under the curve (AUC) for each agent. The expression of multi-drug resistance genes (MDR-1, MRP-1, MRP-2) was detected by reverse transcriptionpolymerase chain reaction (RT-PCR). Glutathione (GSH) concentration was measured by an enzymatic assay. Topoisomerase (topo) I activity was assayed in terms of relaxation of supercoiled plasmid substrate DNA. The IC 50 to anticancer agents ranged widely. The assay AUC indicated that 3 of 5 cell lines (RMG-I, RMG-II, and KK) were sensitive to paclitaxel (PTX), 3 (HAC-2, RMG-I, and RMG-II) were sensitive to 7-ethyl-10-hydroxycamptothecin (SN-38), which is an active metabolite of camptothecin (CPT-11), and only one (HAC-2) was sensitive to cisplatin (CDDP). All cell lines were resistant to mitomycin-C (MMC) and etoposide (VP-16). The MRP-1 gene was detected in all cell lines. Only one cell line showed both MRP-2 and MDR-1 gene expression. Except for HAC-2 cells, expression of MRP genes was related to CDDP resistance, and MDR-1 gene expression was associated with PTX resistance. GSH concentrations increased after exposure to CDDP or MMC in all cell lines. There was a significant correlation between topo-I enzymatic activity and the response to SN-38. The present study revealed several resistance mechanisms in CCC and the results suggested that PTX and CPT-11 might be effective agents to treat CCC.

The present study was conducted to determine whether and how expression of the c-myc gene is related to the response to chemotherapy in patients with epithelial ovarian cancer. This study includes 101 consecutive patients with stage Ic to IV epithelial ovarian cancer who underwent primary surgery followed by platinum-based chemotherapy. Immunohistochemical studies were performed to detect Ki-67 and ARF proteins. Apoptotic cells were identified by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick-end labeling method. Mutation of the p53 gene was screened by polymerase chain reaction (PCR)-single strand conformation polymorphism analysis and confirmed by direct sequencing. mRNA expression of c-myc was determined by means of reverse transcription-PCR. Apoptotic index (AI) and ARF labeling index (LI) were significantly increased and Ki-67 LI was decreased after chemotherapy in patients from whom specimens could be obtained before and after chemotherapy. AI, ARF LI, and Ki-67 LI were not related to p53 gene status. A significant correlation between expression of c-myc and ARF LI was observed. Of 38 patients with measurable lesion, 23 (60.5%) responded to chemotherapy and 15 (39.5%) did not. Tumors with the wild-type p53 gene responded significantly better to chemotherapy than did tumors with the mutation. Responders showed a higher expression of c-myc than nonresponders (468 ± ± ± ±76 vs. 187 ± ± ± ±68). latinum-based combination chemotherapy, currently the standard treatment for ovarian cancer, has achieved a high response rate, but it is limited by the development of resistance to chemotherapy. [1][2][3] Chemoresponse is the most important prognostic factor in ovarian cancer. Many mechanisms have been postulated to explain chemoresistance, including decreased drug accumulation, increased cellular detoxification, and increased DNA repair. [4][5][6][7][8][9] Recent studies suggest that apoptosis is also related to chemoresistance. [10][11][12] Mutation of p53 and overexpression of c-myc have frequently been observed in ovarian cancer. 13,14) p53, which is a cell cycle checkpoint protein, plays a regulatory role in the control of cell proliferation and apoptosis.15) The transcription-regulatory oncoprotein c-Myc controls genes involved in cell growth and apoptosis.16) c-Myc directly induces apoptosis via ARF, and ARF also regulates p53-dependent apoptosis through mdm-2. [17][18][19] In a recent study, consensus sequences for binding p53 and c-Myc were found in the promoter region of immediate early response gene X-1 (IEX-1), which can be associated with either suppression or induction of apoptosis. 20) Additionally, the ability of c-Myc to inhibit IEX-1 expression required the presence of functional p53. These findings suggest that p53 and cMyc may have interacting roles in apoptosis.Several studies have shown the critical role of p53 in executing cell death in response to anti-cancer drugs, and that mutations of the p53 gene are associated with lack of response to anti-cancer dr...

We conducted study to determine whether and how the expression of the hypoxia-inducible factor 1alpha (HIF-1alpha) gene relates to outcome in patients with epithelial ovarian cancer. A total of 66 patients with epithelial ovarian cancer, who underwent primary surgery followed by platinum-based chemotherapy, were entered into this study. We confirmed the expression of HIF-1alpha and the vascular endothelial growth factor (VEGF) by immunohistochemistry. To determine the quantity of HIF-1alpha and VEGF expression, messenger RNA of each gene was measured by real-time reverse transcription-polymerase chain reaction. The cutoff values were determined by the receiver-operating characteristic curve according to survival. The protein expressions of HIF-1alpha and VEGF were strongly observed in the cancer cells. The cutoff value of HIF-1alpha and VEGF gene expression was 6.0 and 3.0, respectively. The expression of HIF-1alpha did not relate to clinical stage, but tumor with low VEGF expression was observed more frequently in stage I patients. The response rate to chemotherapy did not differ between high and low expression of both genes. The overall survival for patients with high expression of HIF-1alpha was significantly lower, but disease-free survival did not differ between high and low expression of HIF-1alpha, whereas both overall and disease-free survival for patients with high expression of VEGF were significantly lower. Multivariate analysis revealed that FIGO stage and HIF-1alpha expression were independent prognostic factors but that VEGF was not. The present study suggested that the expression level of HIF-1alpha could be an independent prognostic factor in epithelial ovarian cancer.

PurposeTo define the median endometrial thickness (ET) in office gynecology is thought to be important for clinical practice. However, there are few reports about ET that have included the general female population on a large scale. The median ET was determined prospectively in premenopausal women who attended office gynecology for cervical cancer screening.MethodsIn total, 849 women were enrolled. The median ET was determined by using transvaginal ultrasound and the relationships between the ET and various clinical factors were analyzed.ResultsThe participants' median age was 38.5 years. The median ET was 8.6 mm (90% and 95% quantiles: 13.8 and 15.8 mm). The ET was not related to their age, symptoms, obstetric history, geographical location, or risk factors for endometrial cancer. In the women with a menstrual cycle length of 28–30 days, the ET was 7 mm on days 1–6, but it increased from 5.4 mm immediately after menstruation (day 7 or 8) to 9.2 mm on days 13–14. Subsequently, the ET increased further to 11.1 mm on day 18.ConclusionIn all the women, the upper limit of the ET was 13.8 mm and 15.8 mm in the 90% and 95% quantile, respectively, in office gynecology.