Self-assembled micellar nanocomplexes comprising green tea catechin derivatives and protein drugs for cancer therapy

In designing drug carriers, the drug-to-carrier ratio is an important consideration because using high quantities of carriers can cause toxicity resulting from poor metabolism and elimination of the carriers(1). However, these issues would be of less concern if both the drug and carrier possess therapeutic effects. (-)-Epigallocatechin-3-O-gallate (EGCG), which is a major ingredient of green tea, has been shown to possess anticancer effects(2-7), anti-HIV effects(8), neuroprotective effects(9), DNA-protective effects(10), etc. Here we show that sequential self-assembly of the EGCG derivative with anticancer proteins forms stable micellar nanocomplexes (MNCs), which have greater anticancer effects in vitro and in vivo than the free protein. The MNC is obtained by complexation of oligomerized EGCG with the anticancer protein, Herceptin, to form the core, followed by complexation of poly(ethylene glycol)-EGCG to form the shell. When injected into mice, the Herceptin-loaded MNC showed better tumour selectivity and growth reduction, and longer blood-half-life than free Herceptin.