Effect of GDF3 expression on mouse hepatoma G1 or G5 cells. (A) Total RNA was extracted from G5 cells cultured in 10-cm dishes and BALB/c mouse liver, and RT-PCR analyses were carried out with primers listed in Table 1. (B) G1 and G5 cells were transfected with empty or GDF3-expressing vectors. Twenty-four hours after transfection, cells were injected subcutaneously into BALB/c mice and tumor diameters were measured on the indicated days. Two experiments with n = 4 were statistically analyzed.