PLK4 and colorectal carcinoma: In contrast, treatment of PLK4-upregulated CRC cells with rapamycin resulted in a significant increase in Beclin1, Atg5 and LC3B-II, as well as p-p38, and a marked reduction in the expression of p-mTOR, CDK4, CDK6, PCNA, and p62 (Figure 4L).