Mechanisms of cisplatin resistance in clear cell carcinoma of the ovary

Resistance of clear cell carcinoma (CCC) of the ovary to platinum-based chemotherapy is associated with a poor prognosis. However, the mechanism underlying the resistance of CCC to platinum has not yet been understood. We conducted the present study to clarify the mechanism of cisplatin (CDDP) resistance in CCC cells. Eleven CCC and 5 serous adenocarcinoma (SAC) cell lines were used in this study. The IC(50) to CDDP ranged from 1.3 to 18.0 microM for CCC cells and from 2.2 to 13.0 microM for SAC cells. There was no correlation between multidrug resistance-associated protein expression and the sensitivity to CDDP in CCC cells. In contrast, the doubling time for CCC cells was significantly longer than that for SAC cells (61.4 vs. 29.8 h). A significant reverse correlation between the S-phase fraction and the response to CDDP was observed (r = 0.647, p < 0.05). The present study suggests that the resistance of CCC to CDDP may be caused by low cell proliferation.     

Exploratory study of effective chemotherapy to clear cell carcinoma of the ovary

Although clear cell carcinoma of the ovary is considered to be a tumor with poor prognosis, the clinical characteristics has not been defined. The aim of this study was to evaluate the response of clear cell carcinoma of the ovary to first and second-line chemotherapy and explore effective chemotherapy. Fifty-three patients with clear cell carcinoma of the ovary were enrolled between 1988 and 1997 at our department. Since taxol was not available in Japan at that time, cisplatin-based combination chemotherapy has been exclusively used as a standard first-line chemotherapy. Retrospective analyses of clinical characteristics and the response to first or second-line chemotherapy were performed. Median age was 52 years (range 27-71 years). Tumors were 34% (18/53) stage I, 19% (5/53) stage II, 38% (20/53) stage III, and 9% (5/53) stage IV. All patients with I or II stage disease had optimal cytoreduction. Out of 25 patients with III or IV stage disease 20% (5/25) had negative residual tumor, 36% (9/25) had <2 cm residual tumor, and 44% (11/25) had >/=2 cm residual tumor. All patients received postoperative platinum-based chemotherapy. Of 23 patients with measurable residual tumor 8.7% (2/23) completely and 13% (3/23) partially responded to first-line chemotherapy consisting of cisplatin, adriamycin and cyclophosphamide (CAP) or cisplatin and cyclophosphamide (CP) by CT scan or second look laparotomy. Presence of endometriosis was 55% (29/53) but was not a prognostic factor. Although overall response rate of ovarian clear cell carcinoma to first-line chemotherapy by CAP or CP was about 22%, EP or EJ consisting of etoposide and cisplatin or carboplatin used as a second-line chemotherapy showed 29% response rate, while CPT-P consisting of CPT-11 and cisplatin showed 40% response rate. Clear cell carcinomas were frequently present at early stage, with association of endometriosis and with poor overall prognosis. Although patients with advanced ovarian clear cell carcinoma seemed to have better response to CPT-P than conventional platinum-based chemotherapy, further studies are required with larger number of patients to draw firm conclusions.     

卵巢透明细胞癌70例临床特点及预后分析

探讨卵巢透明细胞癌的临床、病理特点及预后,回顾性分析我院1982年1月～2001年12月70例原发性卵巢透明细胞癌患者临床资料,对其临床特点与治疗情况进行总结并对预后进行随访,总结其发病规律及临床特点.卵巢透明细胞癌多以腹痛、腹胀和盆腔包块为主要症状（占就诊者80%）,70例患者全部进行手术,满意肿瘤细胞减灭术5年生存率（61.5%）与不满意肿瘤细胞减灭术5年生存率（7.69%）差异有统计学意义.术后病理组织证实单纯透明细胞癌42例,透明细胞癌合并其他上皮性癌28例,合并子宫内膜异位症19例.共65例于术后进行了PT、PAC等化疗.在不同方案、不同疗程比较中,发现PT方案、6个疗程以上化疗组有较高的5年生存率,与PAC组、其他化疗方案组差异有统计学意义,P=0.005.卵巢透明细胞癌临床特点不同于其他的卵巢上皮恶性肿瘤,是上皮癌的一种特殊组织类型,其临床分期早,化疗不敏感,即使是早期亦易复发,预后较差,应引起重视.手术尽量行理想的肿瘤细胞减灭术,术后行6个疗程以上的PT方案化疗,可望改善疗效.     

卵巢透明细胞癌70例临床特点及预后分析

探讨卵巢透明细胞癌的临床、病理特点及预后,回顾性分析我院1982年1月~2001年12月70例原发性卵巢透明细胞癌患者临床资料,对其临床特点与治疗情况进行总结并对预后进行随访,总结其发病规律及临床特点。卵巢透明细胞癌多以腹痛、腹胀和盆腔包块为主要症状(占就诊者80%),70例患者全部进行手术,满意肿瘤细胞减灭术5年生存率(61.5%)与不满意肿瘤细胞减灭术5年生存率(7.69%)差异有统计学意义。术后病理组织证实单纯透明细胞癌42例,透明细胞癌合并其他上皮性癌28例,合并子宫内膜异位症19例。共65例于术后进行了PT、PAC等化疗。在不同方案、不同疗程比较中,发现PT方案、6个疗程以上化疗组有较高的5年生存率,与PAC组、其他化疗方案组差异有统计学意义,P=0.005。卵巢透明细胞癌临床特点不同于其他的卵巢上皮恶性肿瘤,是上皮癌的一种特殊组织类型,其临床分期早,化疗不敏感,即使是早期亦易复发,预后较差,应引起重视。手术尽量行理想的肿瘤细胞减灭术,术后行6个疗程以上的PT方案化疗,可望改善疗效。     

MYC pathway is activated in clear cell renal cell carcinoma and essential for proliferation of clear cell renal cell carcinoma cells

Bone morphogenetic protein 7 (BMP7) is a signaling molecule originally identified based on its ability to form bone. It is essential during development, and more recently has also been implicated in cancer pathogenesis. We have recently shown that BMP7 is overexpressed in breast cancer, and that this increased expression is associated with early bone metastasis formation. In the present study, we explored the possible contribution of BMP7 function to the breast cancer cell phenotype. A two-way approach was applied in which BMP7 was silenced using RNA interference in three cell lines with high endogenous expression or, conversely, exogenous BMP7 was added to the growth medium of five cell lines with low or no BMP7 expression. These manipulations led to diverse cell line-specific phenotypic responses. BMP7 manipulation increased cell growth in two cell lines (BT-474, MDA-MB-231), and BMP7 treatment led to reduced growth in four cell lines (HCC1954, MDA-MB-361, T-47D, and ZR-75-30). Growth changes were due to distinct mechanisms since BMP7 silencing led to growth inhibition via G1 arrest in BT-474 cells, whereas BMP7 treatment protected MDA-MB-231 cells from apoptosis. Furthermore, BMP7 stimulation altered the MDA-MB-231 phenotype by inducing a distinct 2.3-fold increase in cell migration and an even more dramatic 3.9-fold increase in cell invasion. In conclusion, BMP7 can promote and inhibit cell growth in breast cancer cell lines and, in a suitable environment, can also considerably induce breast cancer cell migration and invasion.     

BIGH3 is overexpressed in clear cell renal cell carcinoma

To identify new target marker genes in renal cell carcinoma (RCC), we compared the gene expression profiles of clear cell RCC (cc-RCC) and normal kidney tissue using serial analysis of gene expression. Our results revealed that the transforming growth factor beta induced 68 kDa protein (TGF-betaI: beta ig-h3 (BIGH3), plasminogen activator inhibitor-1 (PAI-1) and transforming growth factor beta1 (TGF-beta1) genes are up-regulated in cc-RCC. To further assess the role of BIGH3 in RCC, we investigated the mRNA expression levels of BIGH3, TGFbeta1, PAI-1 and also of TGF-beta1 related genes in 53 RCC and 30 normal kidney tissues by quantitative real-time RT-PCR (QRT-PCR). We further determined the BIGH3 protein levels in 52 cc-RCC paraffin-embedded tissue samples by immunohistochemistry. BIGH3 mRNA was found to be highly overexpressed in cc-RCC compared with normal tissues with an average ratio of 27. The mRNA levels of TGF-beta1 and PAI-1 were also detected at significantly elevated levels in these cancers. Immunohistochemical analysis of BIGH3 also revealed strong staining in the majority of the cc-RCC samples. In addition, the up-regulation of BIGH3 and PAI-1 was found to correlate with the clinicopathological parameters associated with a poorer patient outcome, whereas TGF-beta1 expression was determined to be unrelated to cancer progression. Strong BIGH3 staining thus tended to be associated with a poor prognosis. BIGH3 was also induced in some RCC cell lines by TGF-beta1 stimulation and this correlated well with PAI-1 up-regulation, suggesting that these enhancements are regulated by a similar mechanism in these tumors.     

Adjuvant chemotherapy with irinotecan hydrochloride and cisplatin for clear cell carcinoma of the ovary

Clear cell carcinoma (CCC) of the ovary has distinct characteristics showing resistance to conventional platinum-based regimen. Our aim was to evaluate the effects of combination therapy with irinotecan hydrochloride and cisplatin (CPT-P), comparing to regimen with paclitaxel and platinum (TP). We retrospective reviewed 172 patients with complete surgical staging procedures including lymphadenenctomy. Forty-six patients received CPT-P and 126 patients were treated with TP. Survival of the two groups was compared. Between CPT-P group and TP group, there was no significant difference in median age, performance status, FIGO stage, rate of optimal cytoreduction, and follow-up period. There was no significant difference in progression-free survival of patients with stage I tumors (p=0.95) and suboptimally debulked stage II-IV tumors (p=0.92). Although there was no significant difference of overall survival, progression-free survival of CPT-P group was significantly better than that of TP group in optimally debulked stage II-IV (p=0.03). Multiple regression survival analysis revealed CPT-P regimen (p=0.02) and residual tumor diameter (p<0.01) were both independent prognostic factors in stage II-IV tumors. The combination of CPT-P was shown to have a potential therapeutic benefit for advanced CCC of the ovary, especially for cases with optimal debulking surgery. However, this is a limited retrospective study, therefore we recommend that the CPT-P regimen be evaluated in a larger prospective study.     

Human agmatinase is diminished in the clear cell type of renal cell carcinoma

The proteome of RCC was analyzed by 2D PAGE to search for tumor-associated proteins. Agmatinase, which hydrolyzes agmatine to putrescine and urea, was identified by mass spectrometry and database searches and shown to be downregulated in tumor cells. Additionally, RT-PCR and Northern blot analyses demonstrated a clearly decreased amount of agmatinase mRNA in tumor cells. The differential expression of agmatinase mRNA was confirmed at the protein level. Western blot analysis showed almost no detectable agmatinase protein in tumor cells compared to corresponding normal renal tissue. Agmatinase mRNA is most abundant in human liver and kidney but expressed to a lesser extent in several other tissues, including skeletal muscle and small intestine. The human agmatinase gene encodes a 352-residue protein with a putative mitochondrial targeting sequence at the N-terminus. Using transfection and immunohistochemical studies, we show that agmatinase is localized in the mitochondria. Immunohistochemical studies revealed that agmatinase in the normal kidney is restricted to tubulus epithelial cells, while in tumors staining was low and heterogeneous. Thus, expression of human agmatinase is altered in RCC. We discuss the consequences of these findings in terms of polyamine, NO metabolism and macrophage function.     

A case of clear cell carcinoma of the ovary responding to a paclitaxel-carboplatin combination chemotherapy

Clear cell carcinoma of the ovary is believed to be chemoresistant; therefore, choosing anticancer agents is often difficult. In this report we present a case of ovarian clear cell carcinoma that showed a significant response to a combination chemotherapy with paclitaxel and carboplatin. The patient is a 51-year-old Japanese female with a history of Gn-RH treatment for endometriosis that was terminated three years before the presentation of this disease. She was referred to our hospital because of a huge abdominal mass. The initial surgery revealed the tumor was a clear cell carcinoma of the left ovary, showing a predominantly solid growth pattern as well as papillary and tubular patterns. Both architectural and nuclear grades were interpreted as 3, and mitotic count was up to 5/10 high-power fields. Therefore, the tumor was considered to be grade 2. A huge para-aortic lymph node metastasis was not resectable. Combination chemotherapy using paclitaxel at 175 mg/m2 in 3 hr intravenous infusion followed by intraperitoneal infusion of carboplatin at AUC of 7.5 as a bolus was administered. The regression rate of the para-aortic lymph node metastasis was 85%, lasting more than 5 months. We believe that the combination of paclitaxel and carboplatin is one treatment choice for clear cell carcinoma of the ovary.     

MYC pathway is activated in clear cell renal cell carcinoma and essential for proliferation of clear cell renal cell carcinoma cells

Clear cell renal cell carcinoma (ccRCC) is the major and aggressive subtype of RCC. Previously, we identified 383 differentially expressed genes by analyzing full-length cDNA libraries of ccRCC and normal kidney tissues. In this study, we applied functional network analysis to the differentially expressed genes for identifying deregulated molecular pathways in ccRCC, and the results indicated that MYC showed a prominent role in the highest scoring network. The upregulation of MYC expression was validated in ccRCC tissues and cell lines. Furthermore, Knockdown of MYC expression by MYC-specific siRNA significantly inhibited the abilities of uncontrolled proliferation, anchorage-independent growth and arrested cell cycle in the G0/G1 phase in ccRCC cells. Moreover, we found that 37 differentially expressed genes were shown to be MYC-target genes, and the upregulation of the MYC-target genes BCL2, CCND1, PCNA, PGK1, and VEGFA were demonstrated. The expression of these MYC-target genes was significantly correlated with the expression of MYC in ccRCC tissues, and knockdown of MYC also suppressed the expression of these MYC-target genes in ccRCC cells. The recruitment of MYC to the promoter regions of BCL2, CCND1, PCNA, PGK1, and VEGFA was shown by Chromatin immunoprecipitation assay. These results suggest that MYC pathway is activated and plays an essential role in the proliferation of ccRCC cells.     

Benign and borderline clear cell adenofibromas of the ovary

The criteria for the diagnosis of benign and borderline clear cell adenofibromas and their biologic behavior were investigated by examination of the clinical and pathologic features of 18 tumors in these categories. Three tumors that showed no significant epithelial atypicality were classified as benign. Twelve tumors that contained glands or small solid nests composed of epithelial cells with nuclear characteristics of low-grade malignancy without invasion of the stromal component of the tumor were designated as borderline. Three predominantly borderline tumors with focal microinvasion of the stromal component were also studied. The 17 patients had nonspecific complaints. Sixteen of the tumors were unilateral without surface involvement; one patient had bilateral borderline tumors. Most of the women were treated by hysterectomy and bilateral salpingo-oophorectomy. Follow-up information was available for 16 of the 17 patients. No recurrences or deaths from tumor occurred in 14 patients (2 benign, 10 borderline, 2 microinvasive). One patient with a borderline adenofibroma had questionable lung metastasis 4 years after presentation, and another patient who had a microinvasive tumor had a pelvic recurrence 3.3 years postoperatively.     

ADIPOQ polymorphism rs182052 is associated with clear cell renal cell carcinoma

Recent studies have indicated that low circulating adiponectin concentrations are associated with a higher risk of several cancers, including renal cell carcinoma. In this case–control study, we examined the frequency of single nucleotide polymorphisms (rs182052G>A, rs266729C>G, and rs3774262G>A) in the adiponectin gene (ADIPOQ) in 1004 patients with clear cell renal cell carcinoma (ccRCC) compared with a group of healthy subjects (n = 1108). Fasting serum adiponectin concentrations were also examined. Logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (95% CI). The association of serum adiponectin concentration with genetic variants was calculated using a multivariate linear regression model. A significantly higher ccRCC risk was associated with the rs182052 variant A allele (adjusted OR, 1.36 and 95% CI, 1.07–1.74 for AA vs GG, P = 0.013; adjusted OR, 1.27 and 95% CI, 1.04–1.56 for AA vs GG+AG, P = 0.019), and this positive association was more evident in overweight subjects. Fasting serum adiponectin was lower in subjects carrying A alleles of rs182052 in both ccRCC patients (β = −0.399, P = 0.018) and healthy controls (β = −0.371, P = 0.024). These results suggest that ADIPOQ rs182052 is significantly associated with ccRCC risk.In this case–control study, we examined the frequency of single nucleotide polymorphisms (rs182052G>A, rs266729C>G, and rs3774262G>A) in the adiponectin gene (ADIPOQ) in 1004 patients with clear cell RCC (ccRCC) compared with a group of healthy subjects (n = 1108). Fasting serum adiponectin concentrations were also examined. Fasting serum adiponectin was lower in subjects carrying minor alleles of rs182052 in both ccRCC patients (β = −0.399, P = 0.018) and healthy controls (β = −0.371, P = 0.024). These results suggest that ADIPOQ rs182052 is significantly associated with ccRCC risk.     

The riminophenazine agents clofazimine and B669 inhibit the proliferation of intrinsically multidrug resistant carcinoma cell lines

The sensitivity to clofazimine, B669 and eight standard anti-tumour chemotherapeutic agents of four intrinsically multidrug resistant (MDR) cell lines [three human hepatocellular carcinoma cell lines (HepG2, PLC and Mahlavu) and a human colorectal carcinoma cell line (CaCo2)] were compared with that of a human cervix epithelioid carcinoma cell line (HeLa). The MDR cell lines and HeLa cells showed equivalent sensitivity to the riminophenazines, methotrexate and 5-fluorouracil, but exhibited ranging levels of resistance to vinblastine, doxorubicin, mitomycin C, daunorubicin, etoposide and vincristine. Riminophenazines may be useful agents in the chemotherapy of tumours with intrinsic MDR.     

Synergistic effects of new chemopreventive agents and conventional cytotoxic agents against human lung cancer cell lines

Non-small cell lung cancer (NSCLC) cells have constitutively high expression of cytosolic phospholipase A2 (cPLA2) and cyclooxygenase (COX) 2. These NSCLC cells also have increased prostaglandin expression (PGE2). Many lung cancers also express 12-lipoxygenase RNA and 12-lipoxygenase protein and biosynthesize 12(S)-hydroxyeicosatetraenoic acid, which correlates with their metastatic potential. Several studies have demonstrated that COX-1 and COX-2 inhibitors could inhibit the in vitro growth of human lung cancer cell lines. In this report, we evaluated the growth-inhibitory effects of sulindac sulfide, a COX-1 and COX-2 inhibitor; exisulind (sulindac sulfone), a novel proapoptotic agent that does not inhibit COX enzymes; and nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor on human lung cancer cell lines. We compared these effects with those of 13-cis-retinoic acid, a chemoprevention agent, and with the cytotoxic chemotherapeutic agents paclitaxel and cisplatin, alone or in combination. Our goal was to develop new chemoprevention and treatment strategies. Each of the six agents tested inhibited the in vitro growth of three NSCLC and three SCLC cell lines at the highest concentration. Paclitaxel was the most potent agent (IC50 = 0.003-0.150 microM); sulindac sulfide, NDGA, and 13-cis-retinoic acid had intermediate potency (IC50 = 4-80 microM), and cisplatin and exisulind were the least potent (IC50 = 150-500 microM). Combination studies showed synergistic interactions for sulindac sulfide, exisulind, and NDGA with paclitaxel, cisplatin, and 13-cis-retinoic acid, regardless of drug-resistance phenotype. At high concentrations, the combination of 13-cis-retinoic acid and each of the five other drugs resulted in a strong synergistic effect. These studies provide a rationale for chemoprevention (exisulind +/- retinoic acid +/- NDGA) and therapeutic (exisulind +/- paclitaxel +/- cisplatin) studies in patients at risk for, or with, lung cancer.     

X-chromosome-linked inhibitor of apoptosis as a key factor for chemoresistance in clear cell carcinoma of the ovary

Background:

X-chromosome-linked inhibitor of apoptosis (XIAP) is one of the anti-apoptotic proteins leading to chemoresistance in several cancers. The aim of this study is to evaluate the impact of XIAP expression upon ovarian clear cell carcinoma (CCC) that has a platinum-resistant phenotype.

Methods:

Tissue microarrays made from 90 CCC patients were analysed for immunohistochemical expression levels of XIAP, c-Met, p-Akt and Bcl-XL. In addition, CCC cell lines were evaluated whether XIAP silencing could modulate sensitivity to platinum agent in vitro.

Results:

High XIAP expression was observed in 30 (33%) of 90 CCC cases, and was associated with c-Met (<0.01) and Bcl-XL (<0.01) expression. Cases with high XIAP expression had lower response rate to primary platinum-based chemotherapy (10% vs 65%, P=0.02). In stages II–IV tumours, high XIAP expression was related with worse progression-free survival (PFS, P=0.02). Furthermore, high XIAP expression was identified as an independent worse prognostic factor for PFS and overall survival. Finally, downregulation of XIAP using XIAP-specific small interfering RNA increased sensitivity to cisplatin in human cancer cells derived from CCC.

Conclusions:

X-chromosome-linked inhibitor of apoptosis expression was correlated with chemoresistance of primary chemotherapy, and identified as a prognostic marker for CCC. X-chromosome-linked inhibitor of apoptosis could be a candidate for new therapeutic target in CCC.     

Survival analysis of ovarian clear cell carcinoma confined to the ovary with or without comprehensive surgical staging

Pure-type clear cell carcinoma (CCC) has been recognized as a distinct subtype of ovarian cancer, showing a resistance to chemotherapy and resulting in poor prognosis. Our aim was to evaluate the effects of complete surgical procedures followed by adjuvant chemotherapy for CCC patients whose tumors were confined to the ovary (pT1M0). During the period of 1987-2005, 56 patients with stage I CCC were identified and two cases were excluded due to retroperitoneal lymph node metastasis. A total of 54 patients were enrolled in the study and divided into two groups: Group A (n=38, 1993-2005) underwent complete surgical staging including pelvic and para-aortic lymphadenectomy. Group B (n=16, 1987-1992) underwent a hysterectomy, bilateral salpingo-oopherectomy, omentectomy without comprehensive lymphadenectomy. Every patient received six courses of adjuvant chemotherapy using a platinum agent. Survival analysis was estimated by the Kaplan-Meier method and prognostic factors were evaluated using a Cox regression model. The clinical characteristics of the two groups were similar, except for the rate of conventional platinum-based chemotherapy (p=0.02). Multiple regression survival analysis revealed that the completion of a comprehensive staging operation was the only independent factor for progression-free survival of stage I CCC patients (p=0.03) and that the chemotherapeutic regimen was not a prognostic factor (p=0.43). The present study indicates that we should accomplish complete surgical staging procedures for CCC confined to the ovary.