The present invention provides compounds to disrupt the eIF4E-eIF4G interaction and pharmaceutically acceptable salts of such compounds. Generally, the compounds are cell-penetrating peptides which bind mammalian initiation factor eIF4E (CPP-eIF4E), wherein the peptide comprises an amino acid sequence selected from the group consisting of SEQ ID NOS: 7, 9-11, 12-26, 27-44 and 45-51. More preferably, the amino acid sequence comprises at least 9 to about 40 amino acids and the mammalian initiation factor eIF4E is human initiation factor eIF4E.