Compositions of the invention comprise 8-oxoguanine glycosylase (OGG1) and SIRT6 activating peptide G-A-G-V-S-A-E-NH.sub.2. Compositions of the invention exhibit anti-aging effects by promoting the repair of skin cell DNA and/or by protecting skin cell DNA from UV damage.

The present invention refers to: a) at least one peptide recognizing tumor endothelial cell markers, the peptide being preferably: an v-integrin ligand, preferably a ligand of v3, v5, v8, 51 and/or v6 integrin, more preferably the peptide includes a sequence having a RGD motif or of a CgA sequence ora ligand of CD 13 receptor, more preferably the ligand includes a sequence having a NGR motif or functional fragments or derivatives or a biologically active variant thereof and b) saporin or functional fragments, derivatives or a biologically active variant thereof.

Provided are methods for introducing a modification to an end of a nucleic acid, thereby labeling the nucleic acid with desired moiety, including to a 3-end, a 5-end or both 3-end and 5-end of a nucleic acid. Also provided are kits for introducing such modification to ends of a nucleic acid.