Figure 5. Rab1A overexpression is a driver for CRC growth.

(A) A panel of human CRC cell lines were analyzed for the level of Rab1A, P-S6K1(T389) and P-AKT(473) by immunoblot (top) and the correlation between the level of Rab1A and the level of P-S6K1(T389) was determined (bottom, shown as in Figure 2E).

(B) Rab1A was knocked down in three pairs of CRC cell lines representing high, moderate and low Rab1A expression, as indicated, and the effect on P-S6K1(T389), S6K, P-AKT(S473) and AKT was analyzed by immunoblot.

(C–E) Rab1A was knocked down in human CRC cell lines expressing high (C), moderate (D), or low (E) levels of Rab1A and the relative growth of these cells was analyzed by SRB assay. Data represent means ± SD in three independent triplicate experiments. NC, control shRNA.

(F–H) Rab1A was knocked down in human CRC cell lines expressing high (F), moderate (G), or low (H) levels of Rab1A and their ability to form colonies was determined. Data represent means ± SD in three independent triplicate experiments (Colony number/well in 12-well plates).

(I, J) Quantification results of tumor growth (I) and representative images of tumors dissected at the end of the study (J) showing the effect of Rab1A knockdown on the growth of DLD-1 xenograft tumors. Data represent means ± SD.

(K) DLD1 xenograft tumors were analyzed by hematoxylin and eosin (HE) staining and by IHC as indicated. Mitotic index is expressed by the number of mitotic nuclei per high power field (HPF). Scale bar = 50 μm.

See also Figure S4.