Growth inhibition and apoptosis induction in ovarian cancer cells.

Standard therapy for the treatment of ovarian cancer is radical surgery followed by radiation and/or chemotherapy using cisplatin and paclitaxel. Unfortunately, some patients relapse after this first line chemotherapy and some patients become platinum-refractory. Therefore, we analyzed two different ovarian carcinoma cell lines for their sensitivity for gamma-irradiation and treatment with cisplatin, irinotecan, paclitaxel and gemcitabine. We found that both cell lines were rather resistant against gamma-irradiation and treatment with cisplatin and irinotecan whereas paclitaxel and gemcitabine resulted in a considerable reduction of the viability of the cancer cells. Both paclitaxel and gemcitabine treatment resulted in the induction of apoptosis. This sensitivity profile might be due to a particular subset of p53, which reacted with monoclonal antibodies DO-1 and PAb1801 but not with PAb1620 and PAb421. Gemcitabine and paclitaxel are highly efficient in the induction of apoptosis in ovarian cancer cells, which express a particular subset of the growth suppressor protein p53. Thus, a sensitivity profile for each ovarian carcinoma seems to be highly recommended before starting treatment.

Progress in molecular mechanisms of tumor metastasis and angiogenesis.

The development of metastases is the major cause of death for cancer patients, however, the mechanisms of tumor invasion and acquisition of capability to metastasize remain unclear. During the past decade, knowledge regarding the molecular and cellular processes involved in the regulation of tumor metastases has dramatically increased and has been focussed on cross-talk between selected cancer cells and the specific organ microenvironment. The three-step development of the invasive phenotype of cancer cells is described: cell attachment, local proteolysis and cell migration. The molecular analysis of invasion-associated cellular activities, mainly the role of homotypic and heterotypic cell-cell adhesions, cell-matrix interactions, proteolysis mechanisms and migration properties of cancer cells, are also discussed. The role of tumor phenotype and microenvironment in the metastatic predilection for a specific organ site is pointed out, considering the recent reports which indicate that the capacity to metastasize might be acquired early during multistep tumorigenesis, thereby also predicting the site of metastasis. In addition, this review summarizes the current knowledge regarding angiogenesis regulation in progressive tumor growth and in the complex, multistep nature of tumor cell dissemination. A better understanding of the linkage between genetic and epigenetic events in metastases development may result in new anticancer treatment strategies.

Comparative analysis of CA125, tissue polypeptide specific antigen, and soluble interleukin-2 receptor alpha levels in sera, cyst, and ascitic fluids from patients with ovarian carcinoma.

BACKGROUND: The serum markers CA125, tissue polypeptide specific antigen (TPS), and soluble interleukin-2 receptor alpha (sIL-2Ralpha) concentrations were determined in sera, cyst, and ascitic fluids from patients with malignant and benign ovarian neoplasms. METHODS: CA125, TPS, and sIL-2Ralpha concentrations were measured in sera, cyst, and ascitic fluids by immunoassays in 67 patients with carcinoma and in 32 patients with benign ovarian neoplasms. RESULTS: CA125, TPS, and sIL-2Ralpha levels were elevated significantly in sera from patients who had ovarian carcinoma compared with patients who had benign neoplasms (P < 0.001). Patients who had International Federation of Gynecology and Obstetrics (FIGO) Stage III-IV disease had significantly higher serum levels for the markers studied compared with patients who had FIGO Stage I-II disease (P < 0.001 for CA125; P = 0.02 for TPS and sIL-2Ralpha). Concurrent measurement of CA125 and sIL-2Ralpha in sera identified 100% of ovarian carcinomas in FIGO Stage I-II. All patients with carcinoma demonstrated markedly higher levels of CA125 and TPS for both cyst and ascites compared with corresponding sera (P < 0.001). The level of sIL-2Ralpha was higher statistically in ascitic fluid compared with the level in serum (P < 0.001); however, its values in sera and cyst fluids were comparable. In ascitic fluid, the CA125 level was significantly higher in patients who had FIGO Stage III-IV disease compared with patients who had FIGO Stage I-II disease (P = 0.002), whereas such correlations were not found for TPS or sIL-2Ralpha. In cyst fluids, the levels of all studied markers were independent of the FIGO stage. In cyst fluids from patients with benign ovarian neoplasms, TPS and sIL-2Ralpha levels were significantly lower compared with the levels in patients with ovarian carcinoma (P < 0.001), whereas the values of CA125 were overlapping. CA125 and TPS concentrations were higher in cyst fluids compared with corresponding sera, whereas sIL-2Ralpha levels were comparable and low in cyst fluids and in the circulation of patients with benign neoplasms. CONCLUSIONS: In patients with ovarian carcinoma, TPS and CA125 concentrations were significantly higher in the place of their generation compared with the concentrations in blood circulation. sIL-2Ralpha values were higher in ascites compared with the values in corresponding sera, and its concentrations in sera and cyst fluids were comparable. The assessment of serum sIL-2Ralpha levels showed potential complementary value to CA125 for the detection of ovarian carcinoma in early FIGO stages; however, a 9% false positive rate limited the significance of cumulative value for a combination of these circulating markers.

Temperature-sensitive ovarian carcinoma cell line (OvBH-1).

OvBH-1 cells from a patient with ovarian clear cell carcinoma were established and their biochemical status was analyzed. Cells grown at 37 degrees C exhibited normal cell cycle distribution, whereas the cells shifted to 31 degrees C were arrested in the G(2) / M phase of the cell cycle. Immunochemical analysis using anti-p53 antibodies (DO-1, PAb240, PAb421, and PAb1620) revealed that only the DO-1 antibody reacted with p53 with a high and similar percentage at both temperatures. PAb240 reacted with a low percentage of cells at 37 degrees C and no reaction was observed at 31 degrees C. PAb421 antibody stained a significantly lower percentage of cells at 37 degrees C than at 31 degrees C. Cells were not stained with PAb1620 antibody and were negative for antibodies against p21(WAF1) and MDM2 proteins independently of the temperature. Sequencing of all coding exons of the p53 gene demonstrated only a neutral genetic polymorphism, i.e. a G-to-A substitution (GAG to GAA) at nucleotide position 13 432. Thus, the observed temperature sensitivity of OvBH-1 cells cannot be ascribed to a p53 primary structure mutation. Based upon immunochemical analyses, we consider, however, that p53 in nuclei of OvBH-1 cells is in a highly unstable conformation. Furthermore, the N-terminal portion of the p53 protein at Ser20 has not been modified, and Lys373 and / or Ser378 of the C-terminus is acetylated and / or phosphorylated. The nuclear location signal of p53 is preserved. Induction of MDM2 protein is uncoupled from the cell regulatory machinery and the induction of p21(WAF1) by p53 is impaired in OvBH-1 cells.

Relations between immunologically different p53 forms, p21(WAF1) and PCNA expression in ovarian carcinomas.

The role of tumor suppressor p21WAF1 expression in epithelial ovarian cancer has not been definitely explained and the clarification of mutual p53 and p21WAF1 relations considering proliferative activity seems to be very important for understanding of a functional link between p53 and cell-cycle control. Therefore the expression of p53 and p21WAF1 was assessed immunohistochemically in a series of 50 ovarian carcinomas considering clinicopathological variables. The reactivity of three anti-p53 monoclonal antibodies (DO-7, PAb240, PAb1620) recognizing immunologically distinct forms of p53 were analysed in relation to p21WAF1 level in individual patients. p21WAF1 was expressed in 24 (48%) of all cases. The detection of p53 protein was related to the antibody applied and DO-7 antibody appears to be better than both PAb240 and PAb1620. However, independently of antibody used significant inter- and intratumoral heterogeneity in p53 and p21WAF1 expression was revealed. The identification of different p53/p21WAF1 phenotypes reflect the complex and multiple relations between these two cell-cycle regulators indicating that in ovarian carcinomas p21WAF1 activation may be both p53-dependent and p53-independent. High cell proliferation was usually accompanied by undetectable or weak p21WAF1 staining. There was no significant correlation between p53 and p21WAF1 expression and histology, stage and grade of ovarian carcinomas (p>0.05).