Figure 2.

Different ncRNAs regulate PDCD4 in mutiple ways. (i) miRNAs target PDCD4 directly to promote tumor progression via several pathways. Briefly, PDCD4 reduces the expression of Snail directly or by NF-κB/Akt pathway and leads to up-regulation of E-cadherin, inhibition of β-catenin dependent transcription, and decrease of the expression of c-Myc and uPAR. Down-regulated c-Myc subsequently inhibits MAP4K1 expression, thereby inhibiting AP-1 transcription to impede proliferation, promotion, and invasion. PDCD4 could decrease CDK4/6 via the upregulation of p21, thus leading to reduced cell proliferation. (ii) LncRNAs could function as oncogene and downregulate PDCD4 expression by recruiting EZH2. (iii) LncRNAs could also function as tumor suprefessor to sponge miRNAs, which may counteract the effects of miRNAs on PDCD4.