Figure 1. Exogenous nucleosides suppress OIS and its associated cell growth arrest. See also Figure S1.

(A) IMR90 cells were infected with control or RAS encoding retrovirus with or without addition of the indicated concentration of nucleosides (NS) at the time of infection. On day 6, drug-selected cells were examined for SAHF formation and SA-β-gal activity.

(B) Quantification of (A). Mean of three independent experiments with SEM. *p<0.05

(C) Same as (A) but examined for expression of RAS, p21, p16, p53 and β-actin by immunoblotting.

(D) Same as (A) but stained for γH2AX foci formation. DAPI counterstaining was used to visualize nuclei.

(E) Quantification of (D). Mean of three independent experiments with SEM. *p<0.05

(F) Same as (A) but labeled with BrdU for 1 hour. The incorporated BrdU was visualized by immunofluorescence. DAPI counterstaining was used to visualize nuclei.

(G) Quantification of (F). Mean of three independent experiments with SEM. *p<0.01

(H) Same as (A) but an equal number of cells were inoculated in 6-well plates. After 2 weeks, the plates were stained with 0.05% crystal violet in PBS to visualize colony formation. Shown are representative images of three independent experiments.

(I) Same as (A) but equal number of cells were seeded in 6-well plates. The number of cells was counted at the indicated time points after infection. Mean of three independent experiments with SEM. *p<0.05 compared with RAS alone cells.