The present invention relates to an ecPNA having the general structure: H2N—X—B—Y—COOH and uses thereof, wherein X is A or C and Y is A or C with the proviso that when X is A, Y is C, and when X is C, Y is A; A represents an oligopeptide structure, the sequence of which comprises a sequence which renders the compound able to enter the nucleus of a cell; B represents a peptide nucleic acid (PNA) structure at least 12 nucleotides in length, the sequence of which is capable of hybridizing with a DNA within the nucleus of the cell, which DNA is within a promoter region of a gene; C represents an oligopeptide structure; and each — represents a chemical linkage between the structures at each side thereof, which may be the same as or different from each other such linkage.