I don't have the Signal Processing Toolbox, so I can't access the cusum function. However, here is a generic example of using three inputs into cellfun, that you should be able to easily craft into your use case:
% The input data
A = {[1 2 3],4,5;
[6 7 8],9,10};
out = cellfun(@(x,y,z)(x.*y.*z),A(:,1),A(:,2),A(:,3),'UniformOutput',false)
I think your equivalent is going to be something like
cellfun(@(x,y,z)(cusum(x,constant1,constant2,y,z)),A(:,1),A(:,2),A(:,3),'UniformOutput',false)
