Targeting PML in triple negative breast cancer elicits growth suppression and senescence

摘要

PML silencing induces senescence. Effect of doxycycline-inducible (150 ng ml ; 3 + 3 days) PML silencing (sh1, sh4, and sh5) on PML protein expression ( , representative of at least three experiments), on the morphology ( , representative images, scale bar, 50 μm), on cell size and granularity ( , FACS analysis, sh1 and sh4,  = 4, sh5,  = 5), on the number of senescent cells ( ;  = 3, representative images of SA-β-Galactosidase assay, scale bar 50 μm ( )) and on the number of BrdU positive cells ( ,  = 4) in MDA-MB-231 cells. Impact of doxycycline-inducible PML silencing (sh4) of established MDA-MB-231 xenografts on PML protein expression ( ), on tumor growth rate represented as the growth rate of each tumor ( , sh4 no dox,  = 10; sh4 dox,  = 12; growth rate was inferred from the linear regression calculated for the progressive change in tumor volume of each individual tumor during the period depicted in Supplementary Fig.  ) and on number of senescent cells measured by p-HP1γ staining ( , sh4 no dox,  = 4; sh4 dox,  = 4); representative images of p-HP1γ positive cells, scale bar 100 μm ( ) of the tumors. Error bars represent s.e.m. p, -value (*  p p t-test was used for cell line data analysis ( , , ) and one-tailed Mann–Whitney -test for xenografts ( , ). sh1, sh4, and sh5: shRNA against , dox: doxycycline, SA-β-gal: senescence-associated beta-galactosidase, BrdU: bromodeoxyuridine, p-HP1γ: phospho-heterochromatin protein-1 gamma, molecular weight markers (kDa) are shown to the right