Cancer Cells Defeated by Nanotech Delivery System

In a new application of nanotechnology to defeat cancer, a bio-degradable nanoscale shell has been developed to carry proteins to cancer cells that signal them to suicide. Only the cancer cells kill themselves, which stops the growth of tumors, while healthy cells are not affected - a big difference of this method developed by a team led by researchers from the UCLA Henry Samueli School of Engineering and Applied Science, compared to chemotherapy that does not discriminate between healthy and cancerous cells.

The tiny shells used are about 100 nanometers in length and are composed of a water-soluble polymer, degrading harmlessly in non-cancerous cells. They contain the cell-destroying material apoptin, a protein complex which was derived from an anemia virus in birds. The protein cargo accumulates in the nucleus of cancer cells and signals to the cell to undergo apoptosis, a programmed self-destruction.

"This approach is potentially a new way to treat cancer," said Yi Tang, a professor of chemical and biomolecular engineering and a member of the California NanoSystems Institute at UCLA. "It is a difficult problem to deliver the protein if we don't use this vehicle. This is a unique way to treat cancer cells and leave healthy cells untouched."

Tests done on human breast cancer cell lines in laboratory mice indeed showed significant reduction in tumor growth. And the process does not present the risk for example of genetic mutation posed by gene therapies for cancer, said Tang.

The polymer shells are developed under mild physiological conditions so as not to alter the chemical structure of the proteins or cause them to clump, preserving their effectiveness on the cancer cells.

Tang's group continues to research ways of more precisely targeting tumors, prolonging the circulation time of the capsules, and delivering other highly sought-after proteins to cancer cells.

Paper:
Muxun Zhao et al., Degradable polymeric nanocapsule for efficient intracellular delivery of a high molecular weight tumor-selective protein complex, Nano Today, 2013, DOI: 10.1016/j.nantod.2012.12.003