Adenoviral vector expressing short hairpin RNA targeting Wnt2B has an effective antitumour activity against Wnt2B2-overexpressing tumours.

Background: The Wnt family encodes multi-functional signalling glycoproteins regulating various normal and pathological processes including tumourigenesis. Wnt2B overexpression is thought to affect tumour progression through the activation of the canonical Wnt pathway.

Method: Experimental studies were conducted using a Wnt2B-inhibiting vector to establish gene therapy against Wnt2B2-overexpressing tumours. A replication-deficient recombinant adenoviral vector expressing short hairpin RNA targeting Wnt2B (Ad-shWnt2B) was constructed. Three Wnt2B2-overexpressing human tumour cells, including A549 cells, Hela cells and PANC1 cells, were used. Thereafter, cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Next, a human tumour xenograft model in nude mice was prepared by subcutaneously implanting tumours derived from A549 cells. Ad-shWnt2B was administered via intratumoural injection every 4days.

Results: First, immunohistochemical studies revealed that high levels of Wnt2B expression appeared in proliferative normal tissues and many human tumour tissues. Furthermore, the Wnt2B2 gene expression was associated with c-Myc and survivin expressions in human lung cancer. Transduction with Ad-shWnt2B effectively downregulated the Wnt2B2 expression in all the three Wnt2B2-overexpressing tumour cells (p<0.0001). The transduction with Ad-shWnt2B significantly reduced the percentage of viable cells in all the Wnt2B2-overexpressing tumour cells (p<0.005). In addition, transduction with Ad-shWnt2B significantly downregulated c-Myc and survivin in A549 cells (p<0.005). Furthermore, the treatment with Ad-shWnt2B exerted a significant antitumour effect against the Wnt2B2-overexpressing A549 xenografts by inducing apoptosis (p<0.01).

Conclusions: Cancer gene therapy using an adenoviral vector expressing short hairpin RNA (shRNA) against Wnt2B was, therefore, found to have a strong antitumour effect against Wnt2B2-overexpressing tumours.