Tuesday, May 10, 2011

N-acetyl-cysteine (NAC): good for some things but dangerous with cancer.

High grade soft tissue sarcomas in one study exhibit high levels of glutathione, especially after Doxirubicin therapy.  This is my situation exactly.  Link to the study here

The article below comes from Jacob Schor a Naturopath specializing in cancer.  

NAC is the precursor to a chemical called glutathione.  Oral NAC is rapidly taken up by the body and quickly converted to glutathione.

Glutathione is the primary antioxidant within all of our cells.  It protects our cells from oxidative damage.  This is a good thing in healthy cells; we prefer that they are not damaged.  But in cancer cells we prefer the opposite.  We want cancer cells to be extra vulnerable to damage.  Cancer cells generate oxidative chemicals referred to in total as reactive oxygen species (ROS) in an attempt to destroy themselves.  Glutathione acts as a brake and prevents them from self-destruction or to use the scientific term, apoptosis. 

Raising glutathione stops cancer cell death. 
Most cancer therapies work to kill cancer cells by increasing the levels of reactive oxygen species within the cancer cells.  This includes radiation therapy, most chemotherapies and most natural therapies. 

Providing cancer cells with NAC, because it will increase glutathione, protects the cancer cells and prevents them from dying. 

We often see NAC being used in studies investigating the mechanisms of how anticancer agents work; they use NAC in a simple trick to see if the drugs are killing cancer cells through the common mechanism of increasing reactive oxygen species.  If adding NAC stops the action of the anticancer agent, than it is assumed it was acting through oxidative action.  Let me find a recent example.

In April 2010, Korean researchers reported on the action of NAC in combination with a proteosome inhibiting chemotherapy drug known as MG132.

 First they showed that MG132 increased the amounts of ROS in lung cancer cells and as expected, the drug slowed the rate of growth of the cancer cells. Then they treated the cancer cells with NAC.  The drug no longer slowed growth rates.  
The procedures followed in this study were not novel. They are routine when evaluating chemotherapy drugs.  First, measure how well the drug works against tumor cells and then measure whether NAC stops the effect.  This tells the scientists to what degree the drug’s action is via reactive oxygen species generation and whether other anti-cancer mechanisms are involved.

It’s not just the medical treatments that NAC will potentially interfere with.  A paper from December 2010 tells us that NAC ‘blocked the antiproliferative’ effect of curcumin, that is stopped it from hindering the growth of cancer cells. 

For the whole story click on the title to follow the link.