Fig. 2

The receptor sortilin is a prerequisite for progranulin-induced CSC-like propagation. a MCF7 cells treated with siRNA against sortilin or scrambled control were pre-treated with either vehicle (PBS) or 1 μg/ml progranulin and analysed for mammosphere-forming capacity and protein expression (Western blot). Results are expressed as relative mammosphere number ± SD (n = 3). **p < 0.01 as calculated by a Student’s t test. Western blot analysis of sortilin expression confirmed sortilin knockdown. b MCF7 cells treated with either vehicle or the sortilin-degrading drug MPEP (10 μM). 3 h later cells were treated with either vehicle (PBS) or 1 μg/ml progranulin for 48 h and analysed for mammosphere-forming capacity. Results are expressed as relative mammosphere number ± SD (n = 3) (top). *p < 0.05 as calculated by a Student’s t test. Western blot analysis of sortilin expression confirmed sortilin degradation after MPEP (10 μM) treatment (bottom). c MCF7 cells treated with either vehicle (PBS) or 1 μg/ml progranulin with or without the small molecule AF38469 (10 μM) and analysed for mammosphere-forming capacity. Results are expressed as relative mammosphere number ± SD (n = 3). **p < 0.01 as calculated by Student’s t test, MPEP 1-[2-(2-tert-butyl-5-methylphenoxy)-ethyl]-3-methylpiperidine