Lokale nicht-virale Gentherapie in kutanen Metastasen von Mammakarzinom und Melanom: Ergebnisse einer Phase-I-Studie mittels Jet-Injektion nackter DNA

Abstract

Background: This phase I clinical trial evaluated safety, feasibility and efficiency of nonviral intratumoral jet-injection reporter gene transfer in patients with skin metastases from melanoma and breast cancer. Methods: Seventeen patients were enrolled. The patients received five jet-injections of β-galactosidase (LacZ) expressing plasmid-DNA (pCMVβ) into a single cutaneous lesion. Clinical and laboratory safety monitoring were performed and systemic plasmid clearance was monitored by quantitative real-time PCR (qPCR) of blood samples throughout the study. All lesions were resected after two to six days. Intratumoral plasmid DNA-load, DNA-distribution and LacZ-expression was analyzed by qPCR, quantitative RT-PCR, Western-blot, immunohistochemistry and X-gal staining. Results: Jet-injection of plasmid-DNA was safely performed in all patients. No serious side effects were observed. Thirty minutes after jet-injection peak plasmid-DNA levels were detected in the blood followed by rapid decline and clearance. Plasmid-DNA, LacZ mRNA- and protein expression were detected in all treated lesions. Quantitative analysis revealed a correlation of plasmid-DNA load and LacZ-mRNA expression, confirmed by Western-blot. Immunohistochemistry and X-gal staining demonstrated LacZ-protein throughout the tumor. Transfected tumor areas were found close and distant to the jet-injection site with varying levels of DNA-load and transgene expression. Conclusion: Intratumoral jet-injection of plasmid-DNA led to an efficient LacZ-reporter gene expression in all patients. No side effects were experienced, supporting safety and applicability of this novel nonviral approach. Based on these results a next step with a therapeutic gene product should determine antitumor efficacy of jet-injection gene transfer.