IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Human ovarian cancer-derived ascitic fluid has mixed effects on CRAds efficacy.
Autor/es:
MARÍA VERÓNICA LÓPEZ; NICASIO CUNEO; MARIELA A. GANGEMI; LEONARDO SGANGA; MARINA DEMONTE; ALEJANDRO SODERINI; OSVALDO L PODHAJCER
Lugar:
Salt Lake City
Reunión:
Congreso; 16th Annual Meeting of the American Society of Gene & Cell Therapy; 2013
Institución organizadora:
American Society of Gene & Cell Therapy
Resumen:
Ovarian cancer is one of the leading gynecologic malignancies and the 5-year survival rate for patients with advanced stage ovarian cancer is still low. Most ovarian cancer patients are diagnosed at advanced stages and more than half of them have ascites which is associated with poor prognosis and reduced quality of life. The ascitic fluid is a permissive reactive tumor-host microenvironment that maintains alive malignant cells previously to their homing to their metastatic site. Beside, ascites is rich in cytokines and growth factors secreted by malignant and mesothelial cells lining in the peritoneal cavity that could act to directly stimulate malignant cell growth. CRAds (Conditionally Replicative Adenoviruses) faces this microenvironment when directly injected into the peritoneal cavity. We have recently developed a stroma-targeted CRAd, AdF512v1 and improved variants whose replication is driven by a 0.5Kb fragment of the SPARC promoter. AdF512v1 was extremely effective in the remission of established human tumors disseminated in the peritoneal cavity of nude mice. Moreover, AdF512v1 was also able to replicate in tumor samples from patients. In this work we improved AdF512v1 by adding DNA sequences containing responsive elements to different patho-physiological conditions that characterize tumor tissue, such as hypoxia and inflammation. The new CRAd was named AdF512v4 and contain a chimeric promoter that combines the 0.5 Kb SPARC promoter, a Hypoxia-Response Element (HRE) and a NFkB-response element (NFkB). The chimeric promoter drives the expression of delta-RB E1A and the CRAd was pseudotyped with a chimeric fiber 5/3. One of the indications for phase I clinical trials of ovarian cancer with CRAds imply its administration into the peritoneal cavity. We collected ascitic fluid from 6 patients and ascities-derived cells from 5 of them. Protein arrays showed high expression levels of IL-6, IL-8, MCP-1, osteopontin, GRO, TGF BP-1 and 2, and NAP-2 among other cytokines and chemokines. In in vitro assays we found that ascitic fluids blocked the lytic effect of AdF512v4 on the ovarian cancer cell lines SKOV-3, PA1 and OV4, as well as on the five cells isolated from patients even at 1:50 dilution. This effect was observed in normoxia and hypoxia. Ascities-derived cells were more susceptible to Ad512v4 lytic activity than the ovarian cancer cell lines. Interestingly, the ascites was also able to stimulate the chimeric promoter activity in an adenoviral context. An in vivo assay aiming to establish the ascites effect on CRAd efficacy in xenografts models of human ovary cancer in nude mice will be presented at the meeting. The identification of the ascities-derived soluble factors responsible for the effects described above might have important implications in the search for improving CRAd efficacy.