Non-invasive Methods to Treat Cancer Through Nanotechnology

Over the past three decades since the beginning of the National Cancer Initiative in 1971, there have been major advances in the diagnosis and treatment of cancer. However, the ravages of cancer continue to be a major healthcare concern of our society and nation. As Dr. Eschenbach, Director of the National Cancer Institute stated in September 2004, “… in spite of those opportunities and those breakthroughs, the painful reality is that as we sit here today, one American every minute continues to die from this disease. It remains the disease that Americans fear most because of the suffering and devastation as well as death it brings, and we know that one out of every two men, and one out of every three women in their lifetime will be told they have cancer.” Current treatments by radiation and chemotherapy are also extremely invasive with excruciating side effects. Nanotechnology promises new methods for noninvasive treatment of cancer with minimal side effects. One of the promising approaches is by targeted destruction of cancerous cells using localized heating.

The destruction of tumors by locally heating tissue sufficient to cause its demise has been under investigation for some time. The benefits of thermal therapeutics over conventional removal by surgery are numerous; most thermal approaches are minimally or non-invasive, relatively simple to perform, and have the potential of treating tumors embedded in vital regions where surgical removal is not feasible. Ideally, the activating energy to heat the tumor would be targeted on the embedded tumor with minimal effect on surrounding healthy tissue. Unfortunately, conventional heating techniques such as focused ultrasound, microwaves, and laser light do not discriminate between tumors and surrounding healthy tissue. Thus success has been modest and typically results in some damage to surrounding tissue. Recent work around the world suggests that nanostructures designed to attach to cancerous cells may provide a very powerful means for highly localized energy absorption at the sites of cancerous cells.

Researchers at Rice University in the USA recently reported work on mice in which gold-coated nanoparticles treated to attach to cancerous cells were heated using infrared radiation. Sources of infrared radiation, in a manner analogous to radio stations, can be tuned to transmit at a narrow band of electromagnetic frequencies. Additionally, dimensions of the “nanoshells” can be changed to absorb a particular infrared radiation frequency. Researchers can thereby choose a frequency of the infrared radiation that couples with the gold coated nanoparticles, and at the same time does not couple to the tissue of the body, enabling selective destruction of cancerous cells and tumors[1].

The results of a carefully controlled experimental trial with mice, while preliminary, were very encouraging. Mice into which cancerous cells were introduced and were treated with the nanoshells-infrared radiation therapy appeared healthy and tumor free more than 90 days later; all those receiving the same introduction of cancerous cells and not treated had their cancers grow to such an extent that they were euthanized after an average of 12 days.

In Europe, work at Charité Hospital in Berlin[2], coupled with scientists at the Friedrich-Schiller-Universität Jena, have shown that magnetic nanoparticles interstitially injected directly into the tumor - heated with radio-frequency radiation[3] – can destroy cancer cells in a human brain tumor and is also believed to enhance the effects of subsequent radiation therapy. The nanoparticles localize on the tumor due to a special biomolecularly modified outer layer – leaving surrounding health tissue with minimum damage.

Smart dynamic nanoplatforms - from NCI Brochure and Professor Raoul Kopelman, University of Michigan

In Japan[4] work at Nagoya University with magnetite cationic liposomes (MCLs) combined with heat shock proteins has shown great potential in cancer treatment as well. Using the MCLs, the researchers demonstrated that they could locally generate heat in a tumor by placing test mice in an alternating magnetic field and not cause the body temperature of the test animal to rise. Following injection of the MCLs and application of an alternating magnetic field, tumor temperature and body temperature differed by 6ºC. The combined treatment strongly inhibited tumor growth over a 30-day period and complete regression of tumors was observed in 20% of the mice.

This parallel progress in applications of nanotechnology for the treatment of cancer illustrates the global interest in nanoscience and its potential application to innovative medical technologies. Further, the fact that several groups, using related but different techniques, can demonstrate positive results increases the chances that this new approach might be a powerful new approach to the treatment of cancer.

[1] “Photo-thermal tumor ablation in mice using near infrared-absorbing nanoparticles,” D.P. O’Neal, L.R. Hirsch, N.J. Halas, J.D. Payne, and J.L. West, Cancer Letters 209, 171-176 (2004)

[2] <http://www.germanyinfo.org/relaunch/info/publications/week/2003/030613/misc2.html>http://www.germany-info.org/relaunch/info/publications/week/2003/030613/misc2.html

[3] “Magnemite nanoparticles with very high AC-losses for application in RF-magnetic hyperthermia,” R. Hergt, R. Hiergeist, J. Hilger, W.A. Kaiser, Y. Lapatnikov, S. Margel, and U. Richter, J. Magnetism and Magnetic Materials 270, 345-357 (2004).

[4] “Hyperthermia using magnetic nanoparticles in an experimental subcutaneous murine melanoma,” A. Ito, F. Matsuoka, H. Honda, and T. Kobayashi, Cancer Immunology Immunotherapy 53 (1), 26-32 (2004).