Cancer tissues consists of two groups named cancer stem cells (CSCs) and cancer cells. The cancer stem cells are related to dissemination and progression of cancer. It is important to eradicate cancer stem cells to cure cancer. Cancer is stubborn because cancer stem cells are resistant to radiotherapy and chemotherapy.
A research group from Osaka University collaborated with Tokyo Institute of Technology and found out that hepatocellular carcinoma stem cells had CD13 surface markers. When cancer stem cells were introduced to CD13 inhibitor ubenimex, hepatocellular carcinoma caused apoptosis (programmed cell death), leading to extinction of the same.
Cancer stem cells reside only in part of tumor tissues therefore, it is essential to develop a way to deliver drugs in higher concentration to the targeted sites. The researchers with the help of poly(ethylene glycol)-poly(lysine) created a drug delivery system that blocks copolymer-ubenimex conjugate. This drug delivery system increases concentration of ubenimex to target cancer stem cells.
Masamitsu Konno, lead author says that they earlier developed a drug delivery system to deliver high concentrated ubenimex and later they developed another DDS which were molecule with 20 ubenimex molecules. They experimented this method on mice by injecting intravenous and intraperitoneal administration. This injection reduced the tumor size significantly which successfully proved that ubernimex can be delivered to cancer stem cells in high concentration.
This drug will be used to treat various diseases. The block polymers used in drug delivery system can be produced easily and demonstrate strong effects. This research results will promote application of the drugs for various diseases but there has been challenges in their delivery.