Murine BLCA cell lines were transduced in-vitro with LV-IFNα using a multiplicity of infection (MOI) of 2:1. IFNα levels were measured by ELISA. Cell viability was assessed using Trypan blue dye exclusion. qPCR was used to identify expression of IFNα target genes. A LV-βGalactosidase reporter construct was delivered intravesically, and urinary IFNα levels were measured in mice treated with LV-IFNα or control virus to assess gene transfer. To assess survival benefit, p53+/- C57/B6 mice were exposed to N-butyl-N- (4-hydroxybutyl)-nitrosamine (BBN) to induce CIS and then treated with LV-IFNα or control virus, and sacrificed when moribund.
Efficient LV-IFNα transduction of BLCA cells was observed at an MOI of 2:1, resulting in increased expression of IFNα and its target genes PDL-1, TRAIL, and IRF7 (p<0.001), and reduced cell viability vs. controls (p<0.001). βGal expression confirmed efficient transduction of murine urothelium. Urinary IFNα levels were elevated in mice receiving LV-IFNα compared with control virus. BBN mice treated with LV-IFNα had longer overall survival than mice treated with control virus (p=0.04). LV-IFNα induced intratumoral CD8+ T cell infiltration, high expression of PD-L1, and inhibited angiogenesis.
In summary, LV-IFNα effectively upregulated IFNα target genes, was cytotoxic to murine BLCA cells, and improved the survival of BBN tumor-bearing mice. LV appears to be a promising vector for intravesical gene delivery.
Presented by: Colin PN Dinney, MD, Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
Written by: Stephen B. Williams, M.D., Associate Professor, Division of Urology, The University of Texas Medical Branch, Galveston, TX. and Ashish M. Kamat, M.D. Professor, Department of Urology, Division of Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX at the 16th Annual Meeting of the International Bladder Cancer Network (IBCN) October 11-13, 2018 - the Inntel Hotels Rotterdam Centre, Rotterdam, The Netherlands