Fig. 4. Zilovertamab inhibits Wnt5a-induced venetoclax-resistance and expression of ROR1-regulated target genes in CLL cells.
A CLL cells expressing ROR1 (n = 13) were cultured in serum-free media and treated with increasing venetoclax doses (0.5 nM to 4 nM), with or without zilovertamab (UC-961, 20 μg/mL) in the presence or absence of exogenous Wnt5a (200 ng/mL). CLL cell viability is represented as the percentage of cells after 16 h of treatment with venetoclax or carrier (DMSO) for each sample. Data are shown as mean ± SEM of three independent experiments. For each dose of venetoclax (Ven), statistical significance was determined by two-way Anova, by comparing the percentage of viable cells after 16 h of treatment with Wnt5a (+Wnt5a) minus the percentage of viable cells after 16 h with Wnt5a and zilovertamab (+Wnt5a +UC-961). B BCL-XL protein expression levels assessed by immunoblot analysis of lysates prepared from ROR1Hi CLL cells (representative of three patients) treated without (−) or with (+) Wnt5a and without (−) or with (+) zilovertamab (UC-961). The membranes were probed with a monoclonal antibody specific for BCL-XL or β-actin, as indicated on the left margin. The density of the β-actin band was used to normalize band density for BCL-XL. The IOD ratios of the band densities of BCL-XL/β-actin normalized with respect to that of CLL cells without Wnt5a or zilovertamab (UC-961) are indicated at the bottom of BCL-XL immunoblots and presented in panel G. C The IOD ratios of BCL-XL are shown as the mean ± SD of three samples without (−) or with (+) Wnt5a and without (−) or with (+) zilovertamab (UC-961). Statistical significance was determined by Paired Student’s t test.