A novel conditionally replicating adenoviral vector with dual expression of IL-24 and arresten inserted in E1 and the region between E4 and fiber for improved melanoma therapy

Abstract

Although the combination of gene therapy and virotherapy for cancer therapy has obtained some encouraging results in vitro and in vivo over the past few years, some improvements of the vectors are still urgently needed to enhance their therapeutic effects for cancers. In order to maximize the anti-cancer activities of conditionally replicating adenoviral vectors (CRAd) vector, we for the first time generated a novel CRAd vector by inserting an expression cassette between E4 and the fiber using homologous recombination and tested this vector in melanoma cancer therapy. By using this novel vector we expressed two therapeutic transgenes, IL-24 and arresten, inserted in E1 and the region between E4 and the fiber, respectively, to test the melanoma inhibitory activities of this oncolytic virus in vitro and in vivo. The two therapeutic transgenes were successfully expressed by the novel CRAd, which was confirmed by western blotting. We then showed that this novel CRAd vector significantly suppressed the tumor growth of melanoma in vitro and in vivo compared with the control by inducing apoptosis and inhibiting angiogenesis. The novel CRAd vector generated in this study holds promise for developing more effective therapeutics for not only melanoma but also other common cancers.

Therapeutic Improvement of a Stroma-Targeted CRAd by Incorporating Motives Responsive to the Melanoma Microenvironment

“…A couple of studies have also shown that a CRAd carrying IL-24 helped in inducing apoptosis of melanoma cells following radiotherapy (Chai et al , 2012; Jiang et al , 2012). Thus, the possibility of acting on human melanoma tumors with an oncolytic virus that can target both the stromal and the malignant compartment, respond to melanoma microenvironment, and whose infectivity can be tailored according to cell surface expression of viral receptors can be of significant importance for melanoma therapeutics.…”

Adenoviruses

“…Adenoviruses have several advantages over some other viral vectors such as retroviruses and adeno-associated virus. Adenovirus vectors can infect a variety of cell types, including non-dividing as well as dividing cells, and can be prepared readily in large quantities in tissue culture (Vetrini and Ng, 2010;Chai et al, 2012) 1.4.1.5 Adenovirus-based vaccines against infectious pathogens Another promising application for adenoviruses is their use as vaccine vectors (Gaydos and Gaydos, 1995). As already mentioned, live, oral, enteric-coated, adenovirus serotypes 4 and 7 vaccines were safely used for years in military training camps to prevent epidemics of acute adenoviral respiratory disease.…”

Construction and Characterization of E1- and E3-Deleted Adenovirus Vectors Expressing Two Antigens from Two Separate Expression Cassettes

“…Early versions of dualexpression vectors carried two versions of the same cassette within E1 that differed in the transgene but contained the identical (Zinn et al, 2002) or different (Liu et al, 2012) regulatory elements. Others used bidirectional promoters to control up-and downstream transgenes placed into E1 (Chai et al, 2011) or two expression cassettes with different promoters placed in tandem into E1 (Irie et al, 2005). Others, similar to our approach, inserted one transgene under the control of a CMV promoter into E1 and a second transgene under the control of the RSV promoter into E3 with both expression cassettes in the same orientation (Niu et al, 2006).…”