Pyrvinium suppresses WNT activation in MSCs isolated from patients with myeloid neoplasms with a del(5q). (A) MSCs were isolated from the BM of 2 del(5q) patients with primary MDS or t-MDS and were treated in vitro with or without 50 ng/mL WNT3A ± 50 nM PT, as indicated, for 16 hours. Nuclear and cytoplasmic fractions were isolated and immunoblotted with antibodies specific for CTNNB1, β-actin, and Lamin A/C. Quantitation of the immunoblots revealed a ∼50% reduction in CTNNB1 levels in samples treated with PT. *A smaller CTNNB1 degradation product. (B) Patient MSCs were treated with WNT3A ± 50 nM PT for 16 hours. RNA was isolated and transcribed to cDNA, and PCRs (run in triplicate) were quantified using Fast-SYBR Green. Gene expression was normalized to the ACTB gene and data are presented as mean ± SEM of 1 patient sample, run in triplicate. PT significantly decreased WNT3A-mediated transcription of WNT target genes, but not the control GAPDH gene. *P < .05. Increased GAPDH may reflect emerging evidence suggesting that GAPDH gene expression can be modulated by external factors.⁵⁸