Identification of Piwil2-Like (PL2L) Proteins that Promote Tumorigenesis
Figure 7
PL2L60 promoting tumorigenesis of human cancer cells is associated with the enhanced cell cycle transition from G0/1 to S phase and increased nuclear NF-κB expression.
Breast cancer cell lines (MDA-MB-231) were stably transduced with Lenti-PL2L60 or Lenti-GFP viral vectors, cloned and analyzed for their cell cycling, expansion and tumorigenic capacity in CB17 SCID mice. A & B, PL2L60 promoted the cell cycle transition from G0/1 to S-phase and cell expansion. PL2L60-transduced and GFP-transduced stable cell lines were cloned and analysis for cell cycle (A) and cell expansion (B). The data of three experiments shown in A are derived from a representative clone of PL2L60-transduced (Clone C5) and GFP-transduced breast cancer cell lines (clone C6C2); and % of S-phase was also summarized in B. The number of cells cultured in 6-well plates (5×104/well) was enumerated at day 5 of culture and summarized in B. **, p<0.01; as compared between the PL2L60-transduced and GFP-transduced cell lines. C, NF-κB (RelA/p65) expression in PL2L60-transduced (231-PL2L60) and GFP-transduced breast cancer cells (231-GFP), as revealed by ICC staining (original magnification: x 400). D & E, Enhanced tumorigenic capacity of 231-PL2L60 cells at the initial stage or latent phase of xenograft tumor formation. D, Shown are the tumor growth curves of 231-PL2L60 and 231-GFP cells in CB17 SCID mice (n = 3/group). E, Living images which were taken at the time as indicated by an arrow in D: An arrow indicates weak GFP signal at the site injected with GFP-231. The data shown are a representative of two reproducible experiments. GFP: 231-GFP; PL2L60: 231-PL2L60. **, p<0.01, as compared between two groups.