RON and cisplatin resistance in ovarian cancer cell lines

RON (recepteur d'origine nantais) tyrosine kinase receptor has revealed its tumorigenic potential in recent studies. RON was reported to be overexpressed in 55% of primary ovarian carcinoma samples and furthermore its activation increases cell motility and invasiveness. In this study, we investigated the correlation between RON expression and chemoresistance in ovarian cancer cells. In A2780 cells, a model featured by high chemosensitivity to cisplatin, stable overexpression of RON was able to reduce sensitivity to this agent, while incubation with a blocking anti-RON antibody (ID1) increased the cisplatin-induced growth inhibition effect. Moreover, we observed an increased RON expression both at the mRNA and protein level in A2780 cells made resistant to doxorubicin and paclitaxel (A2780ADR and TC 1, respectively), two cell lines exhibiting a collateral resistance to cisplatin. OVCAR-3 cells, showing high levels of RON expression, also displayed inherent cisplatin resistance. The morphology observed in these resistant cells is consistent with a scattering phenotype and a RON-activated state. RON expression levels were monitored upon hypoxia. A 2.5-fold increase of RON expression was noticed in response to hypoxia in OVCAR-3 cells, in parallel with a decrease of E-cadherin mRNA. Altogether these results suggest an involvement of RON in the acquisition of cisplatin resistance and highlight the importance of this factor as a promising target for combination with cisplatin-based chemotherapy in ovarian cancer.     

Case report: RAEB in a patient with rheumatoid arthritis treated with methotrexate and infliximab

Anti TNF-alpha drugs seem to be the new frontier of Rheumatoid Arthritis (RA) therapy. The association infliximab methotrexate has been approved for the treatment of RA not responding to the classic therapy, but the short clinical experience in using antiTNF-alpha molecules brings to segnalation of new risks or adverse events. We describe a case of a patient, treated for many years with classic RA therapy, which developed a refractory anemia after treatment with association infliximab-methotrexate.     

Selective impairment of pancreatic A cell suppression by glucose during acute alloxan-induced insulinopenia: in vitro study on isolated perfused rat pancreas

This study was performed in order to investigate the role of insulin in the modulation of pancreatic A cell response to glucose. The isolated perfused rat pancreas model was used: intraislet insulinopenia was induced in vitro by 0.56 mM alloxan infusion over 15 min. Alloxan caused a transitory insulin release but did not affect glucagon secretion. Exposure to alloxan completely abolished insulin response to 20 mM arginine, 1.6 mM glucose, and 11.1 mM glucose. Glucagon response to 20 mM arginine and 1.6 mM glucose was unchanged by alloxan pretreatment compared to control pancreata not treated with alloxan. However, the suppression of glucagon release by 11.1 mM glucose was abolished in the alloxan experiments. Twenty milliunits per ml of insulin infused during 11.1 mM glucose infusion restored glycemic suppression of glucagon release, but it produced only a slight inhibitory effect on A cell function in the presence of 3.9 mM glucose. Our study indicates that glucose is the physiological suppressor of the pancreatic A cell and that, in this regard, insulin exerts only a permissive effect.     

Inhibitory effect of quercetin on primary ovarian and endometrial cancers and synergistic activity with cis-diamminedichloroplatinum (II).

The prognostic significance of flow-cytometric DNA analysis was assessed in 375 stages IB and IIA squamous cell carcinoma patients treated with radical hysterectomy and lymphadenectomy at the Mayo Clinic between 1956 and 1985. Paraffin-embedded samples containing at least 20% tumor were dewaxed, rehydrated, stained with propidium iodide, and analyzed. Among 344 assessable samples, 136 (40%) were diploid and 208 (60%) were nondiploid (26 tetraploid, 158 aneuploid, and 24 polyploid). Diploid cases were further subclassified: 25 high proliferative phase (HPP) (S+G2M greater than 20%) and 111 low proliferative phase. No significant correlation was noted between DNA diploid patterns and stage, tumor size, grade, or histotype, but HPP diploid tumors had a significantly higher risk of nodal metastasis. With a mean follow-up period of 150 months, 62 patients died of disease. No significant difference was observed in survival rates (SR) between diploid and nondiploid tumors, but the subset of HPP diploid tumors had a prognosis significantly worse than that of any other group (P less than 0.01). Other significant variables included nodal metastases, parametrial extension, age, and clinical stage. While ploidy patterns did not assign additional risk to node-positive lesions, HPP diploid tumors in node-negative patients were associated with a significantly lower SR. Multivariate analyses in node-negative patients demonstrated that stage, histologic subtype, and HPP diploid patterns retained prognostic independence.     

Significance of epidermal growth factor receptor expression in primary human endometrial cancer

Radioreceptorial assessment of EGFR expression was prospectively performed on 60 primary human endometrial tumors. Of these, 26 were EGFR-positive while 13 expressed high EGFR levels. High EGFR levels correlated well with poor histopatho-logical grading. No correlation with histopathological type, stage, myometrial invasion, lymph-node involvement or steroid hormone receptor status was observed. Disease-free survival rate was significantly shorter in the cases with high than in the cases with low EGFR levels. These results suggest a potential role of EGFR expression assessment in prognostic characterization of endometrial cancer patients. © 1994 Wiley-Liss, Inc.     

Cathepsin D assay in ovarian cancer: correlation with pathological features and receptors for oestrogen, progesterone and epidermal growth factor.

Using an immunoradiometric assay, Cathepsin-D (Cath-D) concentrations were measured in the cytosol of 68 normal and neoplastic human ovarian tissues. Cath-D levels were higher in malignant tumours than in normal tissue samples (P less than 0.01) and benign tumours (P less than 0.01). In six out of seven cases, metastatic deposits showed Cath-D concentrations higher than the respective primary tumours. Using 12 of 17 pmols.mg-1 protein as cut-off levels, the Cath-D status (high or low) was not related to any pathological parameter. Moreover, no correlation was found between Cath-D levels and receptors for oestrogen, progesterone and epidermal growth factor. Our results indicate that ovarian tumours produce Cath-D. Further studies are needed to evaluate whether this protein could represent a prognostic factor for this neoplasia.     

Quercetin and hyperthermia produce a synergistic inhibitory effect on primary human ovarian-cancer cells

Quercetin (from 0.1 muM to 10 muM) produced a dose dependent inhibition of colony formation of cells from 4 primary ovarian tumors expressing type II estrogen binding sites (type II EBS).The combined effects of quercetin ( 10 muM) and hyperthermia (42-degrees-C) result in a significant synergistic action on three out of four tumors analyzed. Moreover, two other flavonoids tested, rutin and hesperidin, which do not bind to type II EBS, are ineffective in synergizing with hyperthermia. In conclusion our results suggest that hyperthermia could synergize the growth inhibitory activity of quercetin which is probably mediated by the flavonoid interaction with type II EBS.     

p53 overexpression is associated with cytoreduction and response to chemotherapy in ovarian cancer

The aim of this study was to assess the association of p53 status with primary cytoreduction, response to chemotherapy and outcome in stage III-IV primary ovarian cancer patients. Immunohistochemical analysis of p53 was performed on formalin-fixed, paraffin-embedded specimens from 168 primary ovarian carcinomas by using the DO-7 monoclonal antibody. p53 nuclear positivity was found in 84 out of 162 (52%) malignant tumours. A higher percentage of p53 nuclear positivity was observed in patients with advanced stage of disease than in stage I-II (57% vs 23% respectively; P = 0.0022) and in poorly differentiated versus well/moderately differentiated tumours (59% vs 32% respectively; P = 0.0038). The multivariate analysis aimed to investigate the association of FIGO stage, grade and p53 status with primary cytoreduction in 136 stage III-IV patients showed that stage IV disease may influence the possibility to perform primary cytoreduction in ovarian cancer patients. p53-positivity also maintained a trend to be associated with poor chance of cytoreduction. In patients who underwent pathologic assessment of response, cases who did not respond to chemotherapy were much more frequently p53-positive than p53-negative (86% vs 14% respectively; P = 0.012). Moreover, patients with stage III disease and < 2-cm residual tumour were more likely to respond to treatment. In multivariate analysis, FIGO stage and p53 expression were independently correlated with pathologic response to chemotherapy. Time to progression and survival rates were shown not to be different in p53-positive versus p53-negative patients.     

Frequent loss of expression of the cyclin-dependent kinase inhibitor p27 in epithelial ovarian cancer.

p27Kip1 is a member of the Cip1/Kip1 family of cyclin-dependent kinase inhibitors and is a potential tumor suppressor gene. Low levels of p27 are associated with poor prognosis in a variety of tumors, including breast, colon, prostate, and lung carcinomas. In the present study, p27 protein expression was investigated by immunohistochemistry and Western blot analysis in a series of 82 epithelial ovarian tumors [16 classified as low malignant potential (LMP) and 66 classified as primary ovarian adenocarcinomas]. Immunohistochemical analysis revealed frequent loss of p27 expression in primary ovarian adenocarcinomas (33%), with respect to LMP tumors (6%; P = 0.0009). In addition to nuclear staining, cytoplasmic localization of p27 was noted in 45 (55%) of 82 cases. p27 levels inversely correlated with cdk2 kinase activity in a representative subset of tumors. When the clinical outcome of the patients was evaluated in relationship to p27 status, we observed a significant correlation between presence of p27 staining and a longer time to progression (P = 0.032 by log-rank test). These data indicate that loss of p27 is a frequent event in ovarian carcinomas as compared with LMP tumors, suggesting that these tumor types may have different pathogenesis. p27 levels may also represent a useful prognostic marker for predicting disease recurrence in primary ovarian carcinomas.