Perspectives for gene therapy in renal diseases

Selective expression of tumor necrosis factor-related apoptosis-inducing ligand mediated by microRNA suppresses renal carcinoma growth

Renal cell carcinoma (RCC) is the most common types among kidney cancers. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) strongly induces apoptosis in RCC. However, TRAIL therapy also leads to hepatotoxicity. To improve the biosafety, we inserted miRNA response elements (MREs) of miR-138, miR-199, and miR-122 into an adenoviral vector, Ad-TRAIL-3MREs, to restrict TRAIL expression within RCC cells. Luciferase assays showed that MREs can regulate the expression of exogenous gene in RCC cells. Ad-TRAIL-3MREs selectively expressed TRAIL and induce apoptosis in RCC cells, but not in normal cells. MTT assays revealed that Ad-TRAIL-3MREs reduced viability of RCC cells without cytotoxicity to normal cells. Ad-TRAIL-3MREs suppressed the growth of ACHN tumors and exerted no hepatotoxicity in vivo. Collectively, we generated a TRAIL-expressing adenoviral vector under the regulation of MREs. This miRNA-based gene therapy may be a promising strategy for RCC treatment.

Renal pathophysiology after systemic administration of recombinant adenovirus: changes in renal cytochromes P450 based on vector dose

Recombinant adenovirus (Ad) significantly alters hepatic cytochrome P450 (CYP). Because changes in renal function can alter hepatic CYP, the effect of Ad on renal CYPs 4A1, 4A2, 4F1, and 2E1 was evaluated. Male Sprague-Dawley rats were given one of six intravenous doses (5.7x10(6)-5.7x10(12) viral particles/kg [VP/kg]) of Ad expressing beta-galactosidase or saline. CYP protein, activity, gene expression, and serum creatinine (SCr) were evaluated 0.25, 1, 4, and 14 days later. Doses of 5.7x10(11) and 5.7x10(12) VP/kg increased CYP4A protein within 24 hr by 35 and 48%, respectively (p<0.05). A similar trend was observed on day 4. CYP4A1 mRNA doubled 6 hr after doses of 5.7x10(10)-10(12) VP/kg (p<0.01). Similar effects were observed 1 day after each dose tested. CYP4A2 gene expression was 20% above control 1 day after treatment with 5.7x10(10)-10(12) VP/kg and remained high through day 14. CYP4F1 expression was unaffected by all doses (p=0.08). CYP2E1 activity and gene expression were significantly suppressed 24 hr after administration of all doses and began to normalize by day 14 (p<0.01). SCr was significantly reduced (approximately 50%) throughout the study for doses at and below 5.7x10(11) VP/kg. SCr was increased by a factor of 3 by 5.7x10(12) VP/kg and glomerular filtration was significantly reduced (p<0.01). This suggests that changes in renal CYP and corresponding arachidonic acid metabolites may play a role in the documented toxicity associated with the systemic administration of recombinant Ad.