Figure 6. c-Raf is essential for K-Ras^+/G12V induced NSCLCs in mice.

(A) Survival of K-Ras^+/G12V;c-Raf^+/+ (n=22) (open circles) and K-Ras^+/G12V;c-Raf^lox/lox (n=23) (solid circles) mice treated with Ad-Cre at 8 weeks of age.

(B) Whole mount X-Gal staining of lung sections collected from mice with the indicated genotypes 6 months after Ad-Cre treatment. β-Geo positive cells identified by X-Gal staining (blue color) correspond to cells expressing K-Ras^G12V.

Scale bars, 5 mm.

(C) Number of tumors, classified by grade (I-IV), observed in K-Ras^+/G12V;c-Raf^+/+ (n=8) (open bars) and K-Ras^+/G12V;c-Raf^lox/lox (n=8) (solid bars) mice.

Error bars indicate +/− SD of the mean.

p values were calculated according to Student’s t test.

(D) (Top) Southern blot analysis of DNA isolated from individual tumors obtained from K-Ras^+/G12V;c-Raf^lox/lox mice infected with Ad-Cre particles at 8 weeks of age. Tumor DNAs were digested with PstI. The sizes of the diagnostic DNA fragments for c-Raf^lox and c-Raf⁻ alleles are indicated.

(Bottom) Western blot analysis of c-Raf expression in lysates obtained from individual tumors collected 8 months after Ad-Cre treatment of K-Ras^+/G12V;c-Raf^+/+ and K-Ras^+/G12V;c-Raf^lox/lox mice. The presence of c-Raf in tumors of Ad-Cre treated K-Ras^+/G12V;c-Raf^lox/lox mice is due to incomplete cleavage of the c-Raf^lox allele. These results indicate that c-Raf is essential for tumor development. Gapdh was used as loading control.

Migration of the above proteins is indicated by arrowheads.

See also figure S6.