Fig. 3

Knocking down endogenous LRIG1 promotes tumor regeneration in AR⁺ PCa xenografts. a Knocking down endogenous LRIG1 in AR⁺ VCaP cells promotes tumor regeneration and growth. VCaP cells purified from maintenance tumors were infected with non-silencing (NS) or shLRIG1 lentivectors (MOI 10; 12 h) and 5000 (5k) cells were subcutaneously (s.c) injected in male NSG mice. Tumors were harvested 92 days after implantations. Shown on the right are tumor incidence and weight and corresponding P values (χ² test for incidence and Student’s t-test for weight; note that the P value for weight comparison was not statistically significant due to low tumor incidence in the NS group). b, c Limiting dilution tumor regeneration assays in LAPC4 (b) and LAPC9 (c) AD cells upon LRIG1 knockdown. Cells freshly purified from maintenance AD xenografts were infected as in A and implanted at two cell doses in male NOD/SCID mice. Tumors were harvested at the indicated time points. Tumor-initiating frequency (TIF) was calculated and compared (χ² test). d Representative IHC images of LRIG1 (Sigma mAb), Ki67, and cleaved LAMIN A staining (see Fig. 2c for dilutions of these three antibodies) in endpoint VCaP, LAPC4, and LAPC9 xenograft tumors. Tumors derived from LRIG1 KD cells contained more proliferating (Ki67⁺) cells than control tumors. Original magnifications were ×400 and a scale bar was indicated on one panel. e, f Quantification of Ki67⁺ (e) and cleaved LAMIN A⁺ (f) cells in endpoint tumors indicated. Bars represent mean ± SEM by counting 1000–1500 cells from 2 to 3 individual tumors in each model. *P < 0.05; ***P < 0.001 (two-tailed unpaired Student’s t-test). *Source data for Fig. 3a, b, c, e, f are provided as a Source Data file.