Fig. 2

The mechanism of peptides in the process of tumor metastasis. A MPM acted with NDUFA7 to inhibit the level of NAD + /NADH, thus inhibiting the metastasis of tumor cells. B circDIDO1 encoded a novel 529aa protein that directly interacted with poly ADP-ribose polymerase 1 (PARP1) and inhibited its activity. C miPEP133 prevent HSPA9 from interacting with its binding partners, leading to the decrease of mitochondrial membrane potential and mitochondrial mass. D CIP2A-BP binds CIP2A, thus releasing PP2A activity, resulting in decreased expression levels of MMP-2, MMP-9, and Snail. E SEMA4B-211aa inhibits the formation of p85/p110 complex then decreased p110 protein and decreased PI3K signal, finally inhibiting the metastasis. F sPEP1 directly binds to eEF1A1 to promote its interaction with SMAD4, upregulation of downstream target genes, and promotion of self-renewal and tumor metastasis. G EIF6-224aa directly interacted with MYH9, and decreased MYH9 degradation by inhibiting the ubiquitin–proteasome pathway and subsequently activating the Wnt/β-catenin pathway. H cGGNBP2- 184aa interacts with the STAT3, phosphorylates its Thy705 site and initiates the transcription of downstream target genes of STAT3. I Hsa_circ_0006401 peptides decreased the mRNA and protein level of the host gene col6a3 by promoting col6a3 mRNA stabilization. J circCOL6A3_030 promoted GC cell migration by encoding a small peptide called circCOL6A3_030_198aa