How apoptosis occurs in untreated control group? Is this normal fact? - (Jul/19/2015 )

Hi all

I gonna start western blotting to see the expression of apoptosis activators (Bcl-2, Bax, Caspase-3,7 & 9 etc..). Recently I have referred some literatures regarding apoptosis, in their results of western blot I saw constant expression of Bax, pro-caspase-3 and others in control group (Untreated A549 cells) too. I am little confused with this because, usually cancer cells evade Apoptosis. It could be induced by treating with drugs or compound of interest. Then how expression (apoptosis execution genes) occurs in untreated control group? Kindly clarify my doubt... If it is normal fact pls suggest some literature to clarify my doubt..

Thanking you

Warm regards

sakthi 

Bax is constitutively expressed and held in check by BCL2/MCL-1 etc. So western on healthy cells will also show bax. An increase in bax levels is a common obsrvation during apoptosis. Procaspase 3 is the inactive form of caspase and will be picked up in regular cells. In apoptosing cells, you need to look at the activated (cleaved) forms. BCL2 is also always expressed in normal cells, but kept in check by Noxa, PUMA etc which is why they donot undergo apoptosis...

Bax is constitutively expressed and held in check by BCL2/MCL-1 etc. So western on healthy cells will also show bax. An increase in bax levels is a common obsrvation during apoptosis. Procaspase 3 is the inactive form of caspase and will be picked up in regular cells. In apoptosing cells, you need to look at the activated (cleaved) forms. BCL2 is also always expressed in normal cells, but kept in check by Noxa, PUMA etc which is why they donot undergo apoptosis...