Posted on 02/08/2003 6:30:52 PM PST by blam
Sunday, 9 February, 2003, 00:34 GMT
Vitamin 'could help prevent lung cancer'
A drug derived from vitamin A could help prevent former smokers from developing lung cancer, it has been claimed. It may help restore the production of a protein which is believed to protect against the disease.
Researchers from the University of Texas say their findings are not conclusive, but could point the way to the development of "chemoprevention" drugs.
Stopping smoking reduces the risk of someone developing lung cancer, but the genetic damage it causes takes time to disappear - and half of all newly-diagnosed lung cancers occur in former smokers.
It may be possible to reverse some of the genetic damage that has accumulated
Scientists want to find a way to stop this genetic damage from turning into cancer.
Gene therapy
The Texas research focuses on retinoids, which are natural and synthetic compounds related to vitamin A (retinol).
Retinoic acid (RA) is needed for the epithelial cells that line the lung to function normally.
It activates retinoic acid receptors (RARs) which regulate cell growth and death.
Heavy smoking is known to reduce levels of a key receptor, RAR beta.
Loss of that receptor has already been linked to the development of precancerous lesions in the lung.
The Texas University team decided to look at whether genetic therapy could restore its production.
They studied 177 patients who had stopped smoking at least a year earlier.
Biopsies were taken from six sections of patients' lungs before treatment, after the three month trial, and three months after treatment stopped.
The samples were then studied for levels of the RAR beta gene.
Those given a vitamin A derivative called 9-cis retinoic acid (9-cis-RA), saw a 7% increase in expression of the gene, compared to a fall in patients taking a dummy pill.
There was no change in a third group taking a different type of vitamin A derivative.
Protective effect
Dr Waun Ki Hong, head of the Division of Cancer Medicine at the University of Texas, said: "This work shows that we can restore the gatekeeper in those who have quit smoking.
"It may be possible to reverse some of the genetic damage that has accumulated."
Dr Jonathan Kurie, who led the study, said it was important because it was the first to study chemoprevention in former smokers.
Vitamin A derivatives might have the potential to help repair cells damaged by smoking
He added: "The work is a proof of concept, suggesting that compounds like this may prove to have a protective effect against development of precancerous lesions."
But researchers warn the therapy may not be the best drug for lung cancer prevention because it causes side effects such as headaches, skin rashes, and fatigue.
Other researchers are testing different drugs which they hope could act as chemoprevention drugs.
Dr Julie Sharp of Cancer Research UK said: "Tobacco smoking causes nine out of 10 lung cancers so the best way to prevent the disease is not to smoke.
"But many people are ex-smokers or continue to smoke and smoking can also put never-smokers at risk of lung cancer through passive smoking.
"For this reason it's essential to look for other ways of preventing the disease."
She added: "Professor Lotan and his colleagues are experts in chemoprevention, which uses drugs to prevent cancer before it has a chance to develop.
"Their work shows that Vitamin A derivatives might have the potential to help repair cells damaged by smoking. However, more research needs to be done before we can be sure of the clinical benefits."
The research is published in the Journal of the National Cancer Institute.
I thought you had to eat protein because the body did not produce it.
Maybe meateaters have something going for them.
The main thing the body does is make protein. Ever heard of genes?
It's a good idea to eat some live plants every day. Provides some vitamins and mineral you ordinarily might not get.
Yup. The best ones to eat are, brocchli, brussel sprouts, califlower, collards and cabbage. These all originate from a wild cabbage from England.
It is claimed that they are high in anti-cancer agents. (eat tuna, brocchli and rice every day, you'll live forever... okay, maybe a few beans every now and then...and some red wine or beer.)
http://www.spectrum.ieee.org/htmlCache/2003-02-04T215336Z_01_N04382062_RTRIDST_0_SCIENCE-HEALTH-CANCER-LUNG-DC.html
It may be of interest to anyone who owns stock in Ligand Pharmaceuticals. They make 9-CIS-retinoic acid (trade name: Panretin). It's sold in gel form as a topical treatment for Kaposi's Sarcoma. Here's the bit that could be of interest to shareholders:
"Kurie said his team now wants to test related compounds that may be safer. 'We are starting to talk to Ligand Pharmaceuticals about Targretin," he said. This drug has a similar mechanism and has shown promise in a range of cancers. "It is probably better tolerated than 9-cis-retinoic acid,' Kurie said."
It caught my eye because I owned stock in Ligand for years, and finally lost patience and sold my last shares about a year ago, for about what they originally cost. The company had great science, but they never seemed able to translate it into commercial success.
I don't recommend anyone rushing out to buy Ligand; like all biotechs, it's very speculative. Just thought that if anyone already has the shares, this might give them some hope. I notice the share price is as low as I've ever seen it (don't know why, as I no longer follow the company).
If anyone cares, that was 13-CIS-retinoic acid, which I believe is better known as Accutane, the acne drug. A pity it didn't work. It would really have been great if they'd found that a zit cream showed activity against treat lung cancer.
Dr. Sharp just identified herself as a quack.
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