Not sure if that would work, Reza. I always understood Annexin V assay to detect flipping of phosphatidylserine to the outer leaflet of the membrane. This exposes Annexin V to the extracellular space (where we can immunolabel) compared to a viable cell. In Western Blot, everything is lysed, denatured, so the biological indicator of apoptosis (outer vs inner leaflet) isn't there anymore.