Fig. 3

Selective and efficient depletion of SAMHD1 in various tumor types following HSP90 inhibition. a siRNA-mediated knockdown of HSP90 in Molm-13 cells reduced SAMHD1 protein abundance (n = 3). b Quantification of SAMHD1 and HSP90 protein levels, normalized to GAPDH; Data are presented as mean ± s.d. (*p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001). c HEK 293T, AGS, H9, HGC-27, HeLa and d Inoculation of THP-1 cells into 12-well cell culture plates and treated with indicated doses of Pimitespib, IPI-504, PU-H71, or STA-9090 for 18 h. SAMHD1 protein levels were analyzed by western blot (n = 3). e Protein quantification results from the experiments in (d) (n = 3). f Western blot assay of SAMHD1 protein levels in primary AML blasts derived from patients, following exposure to different concentrations of HSP90 inhibitors for 18 h (n = 2 patient samples). g RT-qPCR analysis of SAMHD1 mRNA levels in THP-1 cells treated with indicated concentrations of HSP90 inhibitors (IPI-504, PU-H71, or STA-9090) for 18 h (n = 3), with GAPDH as a normalization control. Data are presented as mean ± s.d. h Cycloheximide (CHX) chase analysis of SAMHD1 protein stability in THP-1 cells. Cells were treated with 25 μM CHX, with or without 1 μM STA-9090, and harvested at the predefined time points (n = 3). i Time course analysis of SAMHD1 protein in THP-1 cells. Cells were treated with 200 nM IPI-504, 200 nM PU-H71, or 20 nM STA-9090 and harvested at the indicated time points for western blot analysis. j MTT assay measuring THP-1 cell viability after 18-hour treatment with various doses of HSP90 inhibitors (n = 3). Data are presented as mean ± s.d. k Diagram illustrating the source organs of the cell types used. l Heatmap displaying SAMHD1 protein abundance in the specified cell lines after 18-hour treatment with 20 nM STA-9090, quantified using ImageJ. GAPDH functioned as a normalization control