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

Abstract

BackgroundThe 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. MethodExperimental 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. ResultsFirst, 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). ConclusionsCancer 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.