The only ways I can think of to specifically activate the transcription of RUNX1 specifically would be to either knockin a stronger promoter instead of the endogenous one or to target the promoter with dCas9 based transcription activator.

You could as well to express RUNX1 from a plasmid. It is not as good as from endogens  locus, but is acceptable in most cases. 

Hi saleemulla 

Runx1 can also induced by growth factor BMP4 , follow this paper 

http://www.ncbi.nlm.nih.gov/pubmed/17213321

good luck