I've never had a problem transfecting DLD-1s (see attached protocol). Cell line info here: http://www.lgcstandards-atcc.org/products/all/CCL-221.aspx?geo_country=gb#characteristics
thanks you very much all of you for your kind suggestions, i started working with hct116 its good but now i am looking for microsatellite stable (MSS) cells which are easy to transfect..dld1 is also a msi line like hct116..kindly suggest some mss line..