Effective gene transfer to human glioma cells using high capacity adenoviral vectors: human glioma cells express substantial levels of CAR and integrin adenoviral co-receptors

MARIANELA CANDOLFI; JAMES F CURTIN; WEIDONG XIONG; KURT M KROEGER; CHUNYAN LIU; ALTAN RENTSENDORJ; HASMIK AGDJANIAN; LALI MEDINA-KAUWE; PHILLIP NG; DONNA PALMER; PEDRO R LOWENSTEIN; MARIA G CASTRO

Washington DC, EEUU

Congreso; American Association for Cancer Research 97 Annual Meeting; 2006

Glioblastoma Multiforme (GBM) is the most common subtype of primary brain tumor and, to date, it has no cure. Although adenoviral vectors have been used for gene delivery to glioma tumors in clinical trials, the infectivity of adenoviral vectors in human glioma cells as well as their expression of adenoviral receptors remains controversial. In the present work we report on the expression of two adenoviral receptors, i.e., Coxsackie adenoviral receptor (CAR) and Integrin aV (INT) in murine and human glioma cells. Further, we also report that novel, gutless high-capacity adenoviral (HC-Ad) vectors efficiently infect and express their respective therapeutic transgenes in glioma cell lines derived from murine and human GBM. We constructed and purified HC-Ad vectors expressing b-Galactosidase, HSV1-thymidine kinase (TK) or human soluble Flt3L (hsFlt3L). These were used to infect mouse GL26 cells, rat CNS-1 cells, and the established human glioma cell lines, U251 and U87, and the primary glioma cell lines, derived from surgical biopsies, i.e., IN859 and IN 2045. All cells tested expressed variable amounts of both, CAR and INT, as detected by immunocytochemistry and Western blots. The infectivity and expression of HC-Ad vectors encoding b-Gal was determined by immunocytochemistry and enzymatic activity. High transgene expression was achieved in all the human glioma cells, and in rat CNS-1 cells, while the expression in GL26 cells was lower. The HC-Ad vector encoding TK was successfully expressed in all the cell lines under study, as detected by immunocytochemistry. In the presence of the prodrug ganciclovir, this vector induced cell death in all the murine and human glioma cells, as measured by flow cytometric analysis of cell death. The HC-Ad vector expressing Flt3L also infected efficiently the different cell lines tested as assessed by immunocytochemistry. Finally, high levels of Flt3L were detected, by ELISA, in the supernatant of infected cultures. Our data show that adenoviral receptors are expressed not only in murine glioma cell lines used in preclinical GBM models, but also in human glioma cell lines and primary GBM cell cultures. Importantly, adenoviral vectors successfully infected human glioma cells and elicited high expression levels of the therapeutic transgenes. Taken together, our data strongly support the use of adenoviral vectors in gene therapy approaches for the treatment of human GBM.