PTGS2 and cancer: For example, Kim et al. reportedtheranostic agent 46, consisting of an acetylated lysineresidue linked to Dox and indomethacin as a COX-2 positive cancer-targetingunit.248 Preliminary solution studies revealedthat 46 on sequential treatment with HDAC and cysteinecathepsin L (CTSL), respectively, resulted in active Dox release withfluorescence enhancement (Figure 19).