i started it like this:

abc
def
ghi

given b=1 and a+b+c,d+e+f etc. =111
so i divide 111 by 3 = 37
and put e=37
then h=73
then i find the closest prime number around 37
which are 31 and 43
i put a=43 and i =31
then c=67 and g=7
then d=61 and f=13