Soy Isoflavones Block Cancer

ARTICLE : 

Soy Isoflavones Block Cancer Cells' DNA Repair Mechanisms While 
Protecting Normal Tissue, Increasing Radiation's Ability To Kill 
Lung Cancer Cells

Main Category: Lung Cancer

Also Included In: Radiology / Nuclear Medicine;  Nutrition / Diet

Article Date: 01 Apr 2011 

A component in soybeans increases radiation's ability to kill lung cancer
cells, according to a study published in the April issue of the Journal 
of Thoracic Oncology, the official monthly journal of the International 
Association for the Study of Lung Cancer. 

"To improve radiotherapy for lung cancer cells, we are studying the 
potential of natural non-toxic components of soybeans, called soy 
isoflavones, to augment the effect of radiation against the tumor cells 
and at the same time protect normal lung against radiation injury," said 
Dr. Gilda Hillman, an associate professor in the Department of Radiation 
Oncology at Wayne State University's School of Medicine and the Karmanos 
Cancer Institute in Detroit. 

"These natural soy isoflavones can sensitize cancer cells to the effects 
of radiotherapy, by inhibiting survival mechanisms which cancer cells 
activate to protect themselves," Hillman said. "At the same time, soy 
isoflavones can also act as antioxidants in normal tissues, which protect
them against unintended damage from the radiotherapy. In a recent study, 
published in the Journal of Thoracic Oncology, we demonstrated that soy 
isoflavones increase killing of cancer cells by radiation via blocking 
DNA repair mechanisms, which are turned on by the cancer cells to survive
the damage caused by radiation." 

Human A549 non-small cell lung cancer (NSCLC) cells that were treated 
with soy isoflavones before radiation showed more DNA damage and less 
repair activity than cells that received only radiation. 

Researchers used a formulation consisting of the three main isoflavones 
found in soybeans, including genistein, daidzein and glycitein. 

Previously, researchers had found that pure genistein demonstrated 
antitumor activity in human NSCLC cell lines and enhanced the effects of 
EGFR-tyrosine kinase inhibitors. This study showed that the soy mixture 
had an even greater antitumor effect than pure genistein. The soy mixture
also is consistent with the soy isoflavone pills used in clinical 
studies, which have been proven to be safe, researchers said. 

The study was supported by the American Institute for Cancer Research. 

Source: 
Renée McGaw
International Association for the Study of Lung Cancer