Adenovirus-mediated p53 gene therapy in osteosarcoma cell lines: sensitization to cisplatin and doxorubicin.

The poor prognosis for patients with metastatic osteosarcoma (OS) indicates that new therapeutic options should be explored. Studies with adenoviral-mediated p53 gene transfer have been conducted in many cancer types including cervical, ovarian, prostatic and head and neck tumors. However, limited work has been carried out with pediatric cancers, including OS. Using three viral constructs containing cDNA for wild-type p53, mutant p53 (Cys135Ser) and lacZ, we studied the effect of adenoviral-mediated gene therapy in four OS cell lines: Saos-2 (p53-/-), HOS (R156P), KHOS/NP (R156P) and MNNG (R156P, F270L). We demonstrated that the virus efficiently enters the cells using the beta-galactosidase assay. Using the MTT assay, we have shown a dose-dependent decrease in cell viability 72 h post-treatment that occurs with Ad-wtp53 but not with Ad-mutp53. We have also shown that treatment with Ad-wtp53 significantly increases sensitivity of the cell lines to cisplatin and doxorubicin, chemotherapeutic agents commonly used in the treatment of OS. Our results indicate that restoration of wt p53 function in OS cells provides a basis for novel approaches to treatment of this disease.

Overexpression of H-Ryk in epithelial ovarian cancer: prognostic significance of receptor expression.

H-Ryk is an atypical receptor tyrosine kinase that is expressed in a differentiation-specific manner in epithelial tissues. We have previously shown by in situ hybridization and immunohistochemistry that H-Ryk is overexpressed in malignant ovarian tumors. In addition, we have demonstrated that overexpression of H-Ryk is transforming in vitro and in vivo. To evaluate whether expression of H-Ryk is a prognostic factor in epithelial ovarian cancer, we carried out a retrospective study of 88 primary malignant ovarian tumors (28 serous tumors, 11 mucinous tumors, 29 endometrioid tumors, 13 clear cell tumors, 3 malignant mixed Mullerian tumors, 1 mixed epithelial tumor, 1 primary peritoneal tumor, 1 undifferentiated tumor, and 1 transitional carcinoma) diagnosed between 1990 and 1993 using immunohistochemistry. On univariate analysis, overall survival decreased significantly with age (P = 0.01); in patients with International Federation of Gynecology and Obstetrics (FIGO) stage II (P = 0.008), FIGO stage III (P < 0.001), and FIGO stage IV (P < 0.001) disease; and in patients with residual disease (residual disease < or = 2 cm, P = 0.007; residual disease > 2 cm, P < 0.001) after surgery. In addition, overexpression of the H-Ryk receptor in malignant epithelium (P = 0.04) and blood vessel (P = 0.01) was associated with a significantly decreased overall survival. H-Ryk blood vessel overexpression (P = 0.03), residual disease > 2 cm (P = 0.006), and residual disease < or = 2 cm (P = 0.01) conferred a significantly shorter progression-free survival. No correlation was found between H-Ryk overexpression and age, histological subtype, degree of differentiation, FIGO stage, or residual disease. Overall, after adjustment for all of the prognostic factors by multivariate analysis (Cox proportional hazards model), residual disease was the most powerful prognostic indicator for overall survival (P < 0.001) and progression-free survival (P = 0.01) in this patient subset. This implies that H-Ryk acts cooperatively with other biological factors in the pathogenesis of ovarian cancer.