Figure 2.

In vivo silencing of CTNNB1 gene by i.v. administration of Centyrin-siRNA conjugate in A431 tumor xenograft model

Mice bearing A431 tumor xenografts were dosed three times every other day with targeted or non-targeted siRNA conjugates containing 10 mpk siRNA or equimolar levels of Centyrin only. Tumors were excised 72 h following the final dose, and CTNNb1 mRNA was assessed by qRT-PCR following tissue lysis (n = 6 mice per group). (A) Silencing with non-half-life extended constructs (red). mRNA silencing is observed with both EGFR-1 and EGFR-2 Centyrin conjugates. Non-binding Centyrin conjugates, Centyrins alone, and vehicle are used as controls. (B) Silencing with conjugates incorporating albumin-binding domain (ABD) fusion for half-life extension (blue). (C) 5′ RACE experiment performed on tumor biopsy from EGFR-1-ABD-siRNA_1-treated animals confirms RNAi mechanism of silencing. PCR products from 5′ RACE assay were run on an agarose gel. Arrow indicates mRNA cleavage product in samples treated with EGFR-1-ABD-siRNA but not vehicle (n = 3 mice per group). Data represent mean ± SEM. ∗p < 0.0001 versus untreated controls, ^#p < 0.0001.