Fig. 3

NUDT5 small molecule inhibitor TH5427 suppresses triple-negative breast cancer growth in vitro and in vivo. A ER-positive cell lines MCF7 and ZR-75-1 and TNBC cell lines MDA-MB-231 and MDA-MB-436 were treated with DMSO control or 10 μM TH5427 at day 1. Cell counts were recorded on days 1, 3, 5, and 7. B Schematic illustration of MDA-MB-231 xenograft tumors. 20 Nude mice were injected with MDA-MB-231 cells, and randomized into two groups of 10 nude mice each, which were treated with either vehicle or 50 mg/kg TH5427 via intraperitoneal injection 5 times per week. Mice were sacrificed when the largest tumor size reached 1000 mm³. 4 mice were found dead after 7 days of TH5427 treatment. Tumor volumes were calculated using the formula (width × width × length)/2. Tumor growth was analyzed using linear regression of log₁₀ (tumor volume), and the difference between tumor growth slopes was compared by Student’s t test (*p < 0.05; ***p < 0.001). C H&E and IHC staining of tumor samples from 20 female nude mice injected with MDA-MB-231 cells into the mammary fat pad. H&E and IHC images of one representative tumor are shown. Additional images from 4 other tumors (2 tumors from vehicle-treated mice and 2 tumors from TH5427-treated mice) are presented in Additional file 3: Figure S3C. Ki67 positivity was compared between treatment and control groups. Also see Additional file 3: Figure S3D of the NUDT5 expression via IHC analysis of the 6 independent tumors outlined in 3C above (3 tumors from vehicle-treated mice and 3 tumors from TH55427-treated mice). NUDT5 expression is also shown via IHC analysis of MDA-MD-361 cells (negative control) and MDA-MB-231 cells (positive control). The statistical difference in these analyses was determined by Student’s t test