Efficient and selective tumor cell lysis and induction of apoptosis in melanoma cells by a conditional replication‐competent CD95L adenovirus

Abstract

The high mortality of melanoma demands the development of new strategies, and gene therapy may be considered provided improvements in efficacy and selectivity. Overexpression of the death ligand CD95L ⁄ FasL has been shown in previous studies as highly effective for apoptosis induction in melanoma cells. For efficient and selective targeting of melanoma, a conditional replication-competent adenoviral vector was constructed (Ad5-FFE-02), which drives CD95L expression by a tetracycline-inducible promoter. For restricting its replication to melanoma cells, the adenoviral E1A gene is controlled by a tyrosinase-derived promoter. Furthermore, adenoviral E1B was deleted and a mutated E1A was used to preferentially support replication in tumor cells. Proving its high selectivity and efficiency, strong expression of E1A and doxycycline-dependent induction of CD95L were characteristic for tyrosinase-positive melanoma cells after Ad5-FFE-02 transduction, whereas absent in non-melanoma cell lines. Importantly, Ad5-FFE-02-mediated cell lysis was restricted to melanoma cells, and induction of apoptosis was found only in tyrosinase and CD95 expressing cells. Finally, the combination of adenoviral replication and CD95L-mediated apoptosis resulted in an enhanced repression of melanoma cell growth. This new adenoviral vector may provide a basis for an efficient targeting of melanoma.

Genetic delivery of an immunoRNase by an oncolytic adenovirus enhances anticancer activity

“…Once the virus has spread inside the patients' tumors, immunoRNase expression would be induced at high concentrations to achieve superior antitumor activity, even when virus replication would be attenuated at this step. Reported tools for external control of gene expression or activity in oncolytic viruses are inducible promoters, artificial riboswitches, and fusion of a destabilizing protein domain . However, each system still needs to be improved to be fully effective in the context of oncolytic viruses: Inducible promoters were reported to lose regulation after amplification of oncolytic virus genomes; Destabilizing domains targeting proteins to the cytosolic proteasome might not be functional for all therapeutic proteins, especially secreted proteins, or might interfere with their activity; and riboswitches with high induction rates in mammalian cells are still elusive.…”

Subtype-Specific Radiation Response and Therapeutic Effect of FAS Death Receptor Modulation in Human Breast Cancer

“…Previously published studies have shown several approaches to target FAS/FAS ligand signaling for cancer therapy, including administration of FAS agonist antibodies or FAS ligand recombinant proteins (22–26), FAS ligand gene therapy (27–29) or use of chemotherapeutic drugs to induce FAS or FAS ligand expression (30–32). Here, to overcome radioresistance in SUM159 and HCC1954 tumors, we hypothesized that activating FAS signaling with radiation may have a synergistic apoptotic effect.…”

Effects of Extracellular Calcium and 1,25 dihydroxyvitamin D3 on Sebaceous Gland Cells In vitro and In vivo

“…Extracts were homogenized and centrifuged at 12,000 × g for 10 min. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis of total proteins were performed as described previously (29). Immunoblotting was performed with rabbit monoclonal antibodies against E-cadherin (1:1000; Cell Signaling, Danvers, MA, USA; cat.…”