Figure 4.

CG2 knockdown induced by CG2 small interfering RNA (siRNA) reduced the potency of cotylenin A (CN‐A) plus rapamycin (Rapa) to induce growth inhibition. (a) CG2‐specific siRNA (siCG2) (20 nM) but not control siRNA (20 nM) reduced the expression of CG2 mRNA in both untreated MCF‐7 cells and CN‐A (2.5 µg/mL) plus Rapa (0.5 ng/mL)‐treated MCF‐7 cells. The expression of (a) CG2 mRNA and levels of (b) CG2 protein and α‐tubulin protein were measured after 2 days. Similar results were obtained in two additional experiments. (c) siCG2‐ or control siRNA‐transfected MCF‐7 cells (0.5 × 10⁴ cells/well in a 24‐well dish) were cultured without () or with () CN‐A (2.5 µg/mL) plus Rapa (0.5 ng/mL) for 4 days. Then, the cell number was determined by MTT assay. The values are expressed as mean ± standard deviation of three determinations. GAPDH, glyceraldehyde 3‐phosphate dehydrogenase.