Tomoko Kurita

Expression of mitochondrial transcription factor A in endometrial carcinomas: clinicopathologic correlations and prognostic significance

Mitochondrial transcription factor A (mtTFA) is necessary for both transcription and maintenance of mitochondrial DNA. This study was conducted to elucidate the clinicopathologic and prognostic significance of mtTFA in patients with endometrial carcinoma. This study investigated the relationship between the immunohistochemical expression of mtTFA and various clinicopathological variables in 276 endometrial carcinomas, including 245 endometrioid adenocarcinomas and 31 nonendometrioid carcinomas (21 serous carcinomas and 10 clear cell adenocarcinomas). Both uni- and multivariate regression analyses were performed. The mtTFA labeling index of endometrioid adenocarcinomas ranged from 0% to 98%, with a median value of 32%, which was selected as the cut-off point for mtTFA expression. The mtTFA expression in endometrioid adenocarcinomas was significantly associated with the surgical stage, myometrial invasion, lymphovascular space invasion, cervical invasion, and lymph node metastasis. In contrast, no correlation between clinicopathologic variables and mtTFA expression was found in nonendometrioid carcinomas. Correlation analysis between mtTFA and p53 expression by using the Pearson test showed significant correlation in endometrioid adenocarcinomas (P = 0.007), but no significant correlation in nonendometrioid carcinomas (P = 0.947). A univariate survival analysis showed that the 10-year overall survival rate of the patients with mtTFA-positive endometrioid adenocarcinoma was significantly worse than that of patients with mtTFA-negative endometrioid adenocarcinoma (80.8% vs. 93.8%, P = 0.012). However, the multivariate analysis revealed that mtTFA expression in endometrioid adenocarcinomas was no independent prognostic factor. The positive mtTFA expression is a useful maker for progression of the tumors and the poor prognosis of the patients in endometrioid adenocarcinomas.

Mitochondrial transcription factor A regulates BCL2L1 gene expression and is a prognostic factor in serous ovarian cancer.

Mitochondrial transcription factor A (mtTFA) is necessary for both transcription and maintenance of mitochondrial DNA (mtDNA). Recently, we reported that mtTFA is expressed not only in mitochondria, but also in nuclei. However, the function of mtTFA in the nucleus has not been clearly elucidated. In the present study, we examined nuclear mtTFA expression in 60 tissue samples of serous ovarian cancer using immunohistochemical analysis and found that 56.7% of serous ovarian cancer patients were positive for mtTFA, whereas 43.3% were negative. Univariate survival analysis showed that the overall 5‐year survival rate was significantly worse for patients with mtTFA‐positive cancer compared with mtTFA‐negative cancer (32%vs 42%, respectively; P = 0.021). To elucidate the function of mtTFA in the nucleus, we investigated BCL2L1, a target gene of mtTFA. There was a significant correlation between nuclear mtTFA expression and BCL2L1 expression in seven ovarian cancer cell lines and in specimens of clinical ovarian cancer. Cellular BCL2L1 was downregulated following transfection of siRNA against mtTFA. BCL2L1 promoter activity was increased after transfection of mtTFA expression plasmid, but decreased after siRNA knockdown of mtTFA. Chromatin immunoprecipitation assays showed that mtTFA was bound to the BCL2L1 promoter region. These results suggest that mtTFA is a prognostic factor for a poor outcome of ovarian cancer and may function as an antiapoptotic factor, regulating genes such as BCL2L1. Furthermore, mtTFA may be a promising molecular target for novel therapeutic strategies for the treatment of ovarian cancer. (Cancer Sci 2012; 103: 239–244)

Mitochondrial Transcription Factor A and Mitochondrial Genome as Molecular Targets for Cisplatin-Based Cancer Chemotherapy

Mitochondria are important cellular organelles that function as control centers of the energy supply for highly proliferative cancer cells and regulate apoptosis after cancer chemotherapy. Cisplatin is one of the most important chemotherapeutic agents and a key drug in therapeutic regimens for a broad range of solid tumors. Cisplatin may directly interact with mitochondria, which can induce apoptosis. The direct interactions between cisplatin and mitochondria may account for our understanding of the clinical activity of cisplatin and development of resistance. However, the basis for the roles of mitochondria under treatment with chemotherapy is poorly understood. In this review, we present novel aspects regarding the unique characteristics of the mitochondrial genome in relation to the use of platinum-based chemotherapy and describe our recent work demonstrating the importance of the mitochondrial transcription factor A (mtTFA) expression in cancer cells.

Expression of estrogen receptor-α as a prognostic factor in patients with uterine serous carcinoma.

Objectives Although the expression of estrogen receptor (ER) is usually found in uterine endometrioid adenocarcinomas, it has recently been reported to be found in some uterine serous carcinomas (USCs). This report describes the clinicopathologic features of USC with an expression of ER-&agr;, with special reference to the prognostic significance of ER-&agr;. Methods The immunohistochemical expression of ER-&agr; was examined in 33 USCs. Greater than 10% staining was defined as an overexpression of ER-&agr;. Cox univariate and multivariate analyses for USCs were performed. Results A total of 7 USCs (21.2%) exhibited an expression of ER-&agr;. All tumors were pure-type USCs and strongly demonstrated an overexpression of p53. The cancer-specific 5-year survival rates of patients with USC without an expression of ER-&agr; and USC with an expression of ER-&agr; were 54.5% and 0.0%, respectively (P = 0.04). The univariate analyses showed an expression of ER-&agr; to be a significant prognostic indicator in patients with USC (P < 0.05). However, multivariate analyses for USCs showed that the surgical stage was an independent prognostic factor, whereas the significance of ER immunoreactivity disappeared. Conclusions Uterine serous carcinoma with an expression of ER-&agr; was associated with advanced-staged tumors and a significantly worse prognosis than that without an expression of ER-&agr;. When an endometrial biopsy specimen reveals USC with an expression of ER-&agr; and an overexpression of p53, the presence of an extrauterine lesion is suggested.

Expression of BAF57 in ovarian cancer cells and drug sensitivity.

The SMARCE1 (SWI / SNF‐related, matrix‐associated, and actin‐dependent regulator of chromatin, subfamily e, member 1) encodes BAF57 protein. Previously, we reported that BAF57 is a predictive marker of endometrial carcinoma. In this study, we investigated BAF57 expression in ovarian cancer cell lines and their sensitivities to cisplatin, doxorubicin, paclitaxel, and 5‐fluorouracil. BAF57 expression was strongly correlated with sensitivities to cisplatin, doxorubicin, and 5‐fluorouracil in 10 ovarian cancer cell lines. Paclitaxel sensitivity was also correlated with BAF57 expression, but without significance. In A2780 ovarian cancer cells, knockdown of BAF57 using specific siRNA increased cell cycle arrest at G1 phase and the sensitivities to these anticancer agents. cDNA microarray analysis of A2780 cells transfected with BAF57 siRNA showed that 134 genes were positively regulated by BAF57, including ATP‐binding cassette, sub‐family G (WHITE), member 2 (ABCG2) encoding breast cancer resistance protein (BCRP). We confirmed that knockdown of BAF57 decreased BCRP expression in ovarian cancer cells by Western blot analysis, and that ABCG2 gene expression might be regulated transcriptionally. These results suggested that BAF57 is involved in ovarian cancer cell growth and sensitivity to anticancer agents, and that BAF57 may be a target for ovarian cancer therapy.

Overexpression of p53 in the endometrial gland in postmenopausal women.

ObjectiveThe p53 signature, which (although morphologically unremarkable) displays diffuse and strong p53 nuclear staining, has been proposed to be a precursor of serous endometrial intraepithelial carcinoma. We examined the overexpression of p53 in postmenopausal endometrial glands. MethodsPostmenopausal endometrial tissues of 82 women with benign disease, including 10 hormone users, were evaluated in this study. Tissues with endometrial hyperplasia and/or polyps were excluded based on a histopathologic review. Expressions of estrogen receptor-&agr;, Ki-67, and p53 were immunohistochemically examined. Apoptotic cells were identified using a terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Overexpression of p53 was categorized as moderate to strong in more than 50% of glandular cell nuclei. ResultsFocal glandular overexpression of p53 was observed in 1 (9%) of 10 and in 8 (11%) of 72 postmenopausal endometrial tissue specimens in women with and women without a history of hormone use, respectively. Among nonhormone users, the median Ki-67 and apoptotic indices in the postmenopausal endometrial glands of women with and women without overexpression of p53 were 16% and 6% (P = 0.007) and 1% and 1% (P = 0.345), respectively. All postmenopausal endometrial glands were positive for estrogen receptor-&agr;, regardless of the overexpression of p53. The postmenopausal endometrial glands of estrogen users exhibited significantly higher Ki-67 and apoptotic indices than those of nonestrogen users (P = 0.001 and P < 0.001, respectively). ConclusionsOverexpression of p53 may be responsible for the high proliferative activity of postmenopausal endometrial glandular cells associated with conditions of low apoptotic cell death.

Trends in the demographic and clinicopathological characteristics in Japanese patients with endometrial cancer, 1990-2010.

Objective Over the past 20 years, the incidence of endometrial cancer has increased remarkably in Japan. The number of elderly females has also increased within the population of Japan. We examined the impact of advanced age on the demographic and clinicopathological characteristics in Japanese patients with endometrial cancer. Methods Data were collected from 319 surgically treated Japanese females with endometrial cancer from the files of the University Hospital of Occupational and Environmental Health, Yahatanishi-ku, Kitakyushu, Japan, between 1990 and 2010. χ2 tests were performed to evaluate the trends in the variables between two decades (A: 116 cases from 1990–2000) and (B: 203 cases in 2001–2010). The histological subtypes were also evaluated based on the immunohistochemical expressions of p53, estrogen receptor, and Ki-67. Results The mean ages ± standard deviation in the decade A group and the decade B group were 57.5 years ± 9.7 years and 61.0 years ± 11.3 years, respectively (P < 0.02). There was an increase in the proportion of patients aged 70 years or older and of high-risk histological tumors including serous carcinoma, clear cell carcinoma, and carcinosarcoma (decade A group and decade B group: 9.5% vs 27.6%, P < 0.001, 10.4% vs 21.6%, P = 0.01, respectively), while the advanced surgical stage (III and IV), obesity (≥25 of body mass index), and nulliparity of the decade A group and decade B group were 23.3% vs 29.1%, P = 0.30, 28.4% vs 33.0%, P = 0.40, and 19.0% vs 21.2%, P = 0.66, respectively. The cancer-specific survival rates in the decade A group and the decade B group were 78.6% and 77.6%, respectively (P = 0.93). Conclusion The increase in number of elderly females in the Japanese population is related to the increase in that of high-risk endometrial cancers. A study is needed to investigate prevention strategies and to improve the treatment of elderly patients with high-risk endometrial cancer.

Prognostic significance of overexpression of p53 in uterine endometrioid adenocarcinomas with an analysis of nuclear grade

Although overexpression of p53 is usually found in uterine serous carcinoma (USC), it is also found in some uterine endometrioid adenocarcinomas (UEA). This report describes the clinicopathological features of the UEA with overexpression of p53 with special reference to a prognostic significance of nuclear grade.

Lovastatin induced Kruppel like factor 2 ( KLF2 ), Kruppel like factor 6 ( KLF6 ) and Ras homolog family member B ( RHOB ) genes and preferentially led to viability reduction of Cisplatin-resistant cells

It was reported that statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase that are used to prevent hypercholesterolemia, have antitumor activity in several cancers. In this study, we investigated the cell viability of statins in Cisplatin-resistant HCP4 and PCDP5 cells compared with their parent Hela and PC3 cells, respectively, and found that HCP4 and PCDP5 cells were 37-fold and 18-fold more resistant to Cisplatin but 13-fold and 7-fold more sensitive to Lovastatin by cell proliferation assay. Lovastatin induced the apoptosis of HCP4 cells more rapidly and to greater extent than in Hela cells as assessed by flow cytometry and western blotting analyses. The MVA pathway was not involved in this acquired Cisplatin resistance. To elucidate the mechanism underlying the reduced viability to Lovastatin, we performed cDNA microarray analysis and identified 65 and 54 genes that were induced more than 2-fold by Lovastatin in HCP4 and PCDP5 cells, respectively. Of these, only three genes, KLF2, KLF6, and RHOB, were commonly induced between HCP4 and PCDP5 cells. These mRNAs were strongly induced by Lovastatin with transcriptional regulation in HCP4 cells. Consistent with transcription, the protein expression of RHOB also was induced by Lovastatin. The induction of these genes was associated with cell cycle arrest and apoptosis. Combination treatment with Cisplatin and Lovastatin resulted in an agonistic effect in Hela and PC3 cells and an antagonistic effect in HCP4 and PCDP5 cells. These results suggest that statins might have the potential to overcome Cisplatin resistance as single-agent therapy.

Effect of menopause on hormonal receptors in ampullae of the fallopian tube with a special reference to the p53 signature

Objectives Age-related changes in the expression of hormonal receptors have not been well examined in the fallopian tube (FT). We herein report the effect of menopause on the hormone receptors in ampullae of the FTs (AFTs), in comparison with cortical inclusion cysts (CICs) of the ovary. Methods A total of 84 AFTs and 16 fimbriae of FTs, which were obtained from 26 premenopausal and 58 postmenopausal women; and 27 postmenopausal CICs were immunohistochemically studied for the expression of p53, Ki-67, estrogen receptor-alpha (ER-α), and progesterone receptor A (PRA). Apoptotic cells were identified using a TUNEL assay. Results Postmenopausal AFTs showed a significantly lower labeling index (LI) for Ki-67 (P<0.001), apoptosis (P=0.03), and PRA (P<0.001) than premenopausal AFTs. No significant correlation with immunohistochemical markers was found in premenopausal AFTs, but the LI for PRA was positively correlated with that for Ki-67 (P=0.004) and inversely with that for p53 (P=0.023) in postmenopausal AFTs. The expression of immunohistochemical markers was closely correlated between ampullae and fimbriae of the FT. The p53 signature (p53S) was detected in five postmenopausal AFTs (mean age: 70.2 years) and was not detected in any CICs. The immunohistochemical profile of p53S was low expression of Ki-67, apoptosis, and PRA, and high expression of ER-α. The expression of PRA in CICs was significantly higher than that in AFTs (P=0.001). Conclusion The expression of PRA was significantly lower in postmenopausal AFTs than in premenopausal AFTs, whereas the expression of PRA was well preserved in postmenopausal CICs.