In our study, we found that combination treatment did not significantly affect the mRNA expressions of elF5A, NEDD4, PEAK, SMURF2, UBCH5 (Additional file 1: Figure S1A to S1J), but significant increased β-TrCP mRNA level (Fig. 4A and B) and protein level (Fig. 4C) in the CRC cells. The gene discussed is NEDD4; the disease is colorectal carcinoma.