PDCD4 and malignant colon neoplasm: Additionally, curcumin was effective at inhibiting tumor growth, invasion and in vivo metastasis of human RKO and HCT-116 colon cancer cells (wild-type p53+/+) in the chicken-embryo-metastasis assay in part by down-regulating the transcriptional expression of micro RNA-21 and up-regulating the programmed cell death protein-4 (PDCD4), which is a target of micro RNA-21 [168].