Fig. 5
SETDB1 methylation of PLK3 is critical for BCSCs properties and metastasis. A Effects of ectopic expression of PLK3 WT or the 2KM mutant on mammospheres formation in MDA-MB-231/sh115 and BT549/sh115 BCSCs. B Limiting dilution mammosphere-forming assays of effects of ectopic expression of PLK3 WT or the 2KM mutant. C–F Effects of ectopic expression of PLK3 WT or the 2KM mutant on cell invasion (C), lung metastasis (D, E), and mouse lifespan (F). A cohort of athymic nude mice (n = 6 per group) were implanted with 1 × 105 MDA-MB-231 BCSCs which were transfected with either control shRNA (shC) or sh115, with or without ectopic expression of PLK3 WT or PLK3 2KM mutant via the lateral tail vein. After 14 days, the mice were euthanized and the number of macroscopic lesions on the lung surfaces was quantified at necropsy. The cohorts consisted of mice injected with MDA-MB-231 /shC + EV, MDA-MB-231 /sh115 + EV, MDA-MB-231 /sh115 BCSCs with PLK3 WT or the 2KM mutant. Independent experimental groups under the same conditions were performed to calculate the animal survival (n = 6). Scale bar, 100 μm. Data are representative of three independent experiments with similar results. Error bars, ± SEM. ***P < 0.001, by paired two-tail t-test or log-rank analysis