Figure 4.

Role of LRP6 in adenoma formation and growth of colorectal cancer cells. (A) Polyp number was counted in 12-week-old Lrp6^loxP/loxP; Villin-Cre; Apc^Min/+ small intestines compared to controls (Lrp6^loxP/+; Apc^Min/+ or Lrp6^loxP/loxP; Apc^Min/+) (n ≥ 5). (B) Small intestinal polyp size (diameter) was analyzed in Lrp6^loxP/loxP; Villin-Cre; Apc^Min/+ and control mice (n ≥ 5). (C) Expression of a shRNA against LRP6 (shLRP6) or a non-target shRNA (shCTRL) was induced with 50 ng/mL doxycycline for 48 h in HCT116 and SW48 cells. Loss of LRP6 expression was determined by Western blot. (D) shLRP6 or shCTRL expression was induced with 50 ng/mL doxycycline 48 h before seeding cells at low density for clonogenic assays. Cells grown for 14 days were stained with crystal violet and colonies counted. Three independent experiments are summarized in the graph. (E,F) shLRP6 or shCTRL expression was induced with 50 ng/mL doxycycline 48 h before soft agar seeding. HCT116 cells were grown for 14 days and SW48 cells for 21 days in soft agar before MTT staining. The number of colonies (E) and their size (F) were evaluated. Three independent experiments are summarized in the graph. Data are expressed as mean ± SD. Paired t-test.