Posted: October 16, 2006

Nanoparticle targets cell membranes, triggers cancer cell death

(Nanowerk News) One of the unusual properties of tumor cells is that their cell membranes are more fluid and less rigid than those of normal cells. To take advantage of this difference in order to improve anticancer drug delivery, a team of investigators at Sojo University in Japan has developed a polymer-lipid hybrid nanoparticle that distinguishes between malignant and healthy cells.
Reporting their work in the journal Bioorganic and Medicinal Chemistry Letters ("Membrane targeted chemotherapy with hybrid liposomes for colon tumor cells leading to apoptosis"), Ryuichi Ueoka, Ph.D., Pharm.D., and colleagues describe their work with a nanoparticle made by mixing two different nanoparticles and forcing them to fuse into one hybrid nanoparticle through the use of high frequency sound waves. When added to cultured cancer cells, these particles fuse with the tumor cell membrane. In contrast, these nanoparticles show only a slight ability to fuse with normal cells.
Nanoparticle fusion with malignant cells has a profound effect on cell viability. Soon after fusion, the cells begin producing enzymes that trigger programmed cell death, or apoptosis. Enzyme levels peak within one to two hours, triggering cell death. Given that this effect is seen with the nanoparticles themselves, these data suggest that using such nanoparticles to deliver antitumor drugs could have a profound killing effect on tumor malignant cells.
Efforts to treat cancer using genes and other oligonucleotides, such as short interfering RNA (siRNA), that turn off the biochemical processes that trigger malignancies have been hindered by difficulties in delivering nucleic acids to tumors. Nanoparticles hold promise for solving these issues, and a recent report from researchers at the Singapore Agency for Science, Technology and Research demonstrates that nanoparticle-based oligonucleotide delivery systems can also deliver drugs to tumors, increasing the therapeutic effect of both agents.
Source: National Cancer Institute