Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING
BioConferenceLive
JIB

Terahertz Pulses Simultaneously Kills Skin Tissue, Increases Tumor-Suppressing Proteins

By BiotechDaily International staff writers
Posted on 01 Apr 2013
Terahertz (THz) radiation, a sliver of the electromagnetic spectrum that lies in the middle region between microwaves and infrared light, is providing significant benefits in medical diagnostics and scientific research.

As scientists and engineers find more real-world uses for this type of radiation, however, questions remain about its potential human health risks. New research performed on lab-grown human skin suggests that short but powerful bursts of THz radiation may both cause DNA damage and increase the production of proteins that help the body fight cancer. The findings, which are the result of a collaboration between physicists at the University of Alberta (Edmonton, Canada) and molecular biologists at the University of Lethbridge (Lethbridge, Canada) was published March 18, 2013, in the Optical Society’s (OSA) open-access journal Biomedical Optics Express.

“While these investigations of the biological effects of intense THz pulses are only just beginning,” said Dr. Lyubov Titova, with the University of Alberta and a member of the research team, “the fact that intense THz pulses can induce DNA damage but also DNA repair mechanisms in human skin tissue suggests that intense THz pulses need to be evaluated for possible therapeutic applications.”

THz photons, similar to their longer wavelength cousins in the microwave range, are not strong enough to disrupt the chemical ties that bind DNA together in the nucleus of cells. These waves, however, have just the right frequency to galvanize water molecules, causing them to vibrate and generate heat, which is why microwave ovens are so effective at cooking food. For this reason, it was believed that heat-related injuries were the primary risks posed by THz radiation exposure.

Recent theoretic studies, however, suggest that intense THz pulses of picosecond (one trillionth of a second) duration may directly affect DNA by amplifying natural vibrations (so-called “breathing” mode) of the hydrogen bonds that bind together the two strands of DNA. As a result, “bubbles” (openings in DNA strands) can form. According to the researchers, this brought up the question if intense THz pulses can destabilize DNA structure enough to cause DNA strand breaks.

As shown in earlier animal cell culture studies, THz exposure may indeed affect biologic function under specific conditions such as high power and extended exposure. There is, however, a huge gap between animal research and conclusions that can be drawn about human health.

In a first of its kind study, the Canadian researchers exposed laboratory-grown human skin tissue to intense pulses of THz electromagnetic radiation and have detected the telltale signs of DNA damage through a chemical marker known as phosphorylated H2AX. At the same time, they observed THz-pulse induced increases in the levels of multiple tumor-suppressor and cell-cycle regulatory proteins that facilitate DNA repair. This may suggest that DNA damage in human skin arising from intense picosecond THz pulse exposure could be quickly and effectively repaired, therefore lessening the risk of carcinogenesis.

The researchers used a skin tissue model made of healthy, human-derived epidermal and dermal cells. This tissue is able to undergo mitosis and is metabolically active, thus providing a suitable platform for assessing the effects of exposure to high intensity THz pulses on human skin. For their study, Dr. Titova and her colleagues exposed the skin tissue to picosecond bursts of THz radiation at levels far above what would typically be used in current real-world applications. They then examined the sample for the presence of phosphorylated H2AX, which “flags” the DNA double-strand break site and attracts cellular DNA repair machinery to it.

“The increase in the amount of phosphorylated H2AX in tissues exposed to intense THz pulses compared to unexposed controls indicated that DNA double strand breaks were indeed induced by intense THz pulses,” noted Dr. Titova. Once DNA breaks occur, they can ultimately lead to tumors if unrepaired. “This process,” she continued, “is very slow and cells have evolved many effective mechanisms to recognize damage, pause cell cycle to allow time for damage to be repaired, and—in case repair is unsuccessful—to prevent damage accumulation by inducing apoptosis, or programmed cell death of the affected cell.”

The researchers validated that these cellular repair mechanisms were taking place by detecting an elevated presence of multiple proteins that play vital roles in DNA repair, including protein p53 (frequently called “a guardian of the genome”); p21, which works to stop cell division to allow time for repair; protein Ku70, which helps reconnect the broken DNA strands; and several other important cell proteins with known tumor-suppressor roles. These observations indicate that exposure to intense THz pulses activates cellular processes that repair DNA damage. However, the researchers noted, it is too soon to make forecasts on the long-term implications of exposure.

“In our study we only looked at one moment in time—30 minutes after exposure,” Dr. Titova said. “In the future, we plan to study how all the observed effects change with time after exposure, which should allow us to establish how quickly any induced damage is repaired.”

The Canadian researchers hope to study the potential therapeutic effects of intense THz radiation exposure to see if directed treatment with intense THz pulses can become a new approach to combat cancer.

Related Links:

University of Alberta
University of Lethbridge



comments powered by Disqus

Channels

Genomics/Proteomics

view channel
Image: Microcomputed tomography images (top) and histology images (bottom) of the knees of mice fed a very high fat diet containing omega-3 fatty acid supplement (left) or only omega-6 fatty acids (right) after a knee injury. The omega-6 diet showed abnormal bone remodeling and calcified tissue formation in the joint (white arrow). The omega-6 diet also showed significant loss of cartilage (red staining, yellow arrowhead) and increased joint inflammation (Photo courtesy of Duke University).

Dietary Omega-3 Fatty Acids Moderate Severity of Osteoarthritis in a Mouse Model

Researchers working with an osteoarthritis (OA) obese mouse model found that the fat content of the animals' diet contributed more to the development or arrest of OA than did body weight.... Read more

Drug Discovery

view channel
Image: Molecular rendering of the crystal structure of parkin (Photo courtesy of Wikimedia Commons).

Cinnamon Feeding Blocks Development of Parkinson's Disease in Mouse Model

A team of neurological researchers has identified a molecular mechanism by which cinnamon acts to protect neurons from damage caused by Parkinson's disease (PD) in a mouse model of the syndrome.... Read more

Therapeutics

view channel

Vaccine Being Developed for Heart Disease Close to Reality

The world’s first vaccine for heart disease is becoming a possibility with researchers demonstrating significant arterial plaque reduction in concept testing in mice. Klaus Ley, MD, from the La Jolla Institute for Allergy and Immunology (LA Jolla, CA, USA), and a vascular immunology specialist, is leading the vaccine... Read more

Business

view channel

A Surge in IPOs Revitalize Investments for the Global Pharma and Biotech

Anti-infective drugs, oncology, and pharmaceutical contract laboratories attract the most investment up to now. The intensified private equity and venture capital (PEVC) deal activity in the global healthcare industry during the recession years, 2008–2010, witnessed a waning post-2010. However, the decline in deals... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.