Methods for treating a subject in need thereof are provided which include administering a pharmaceutical composition comprising a protein transduction reagent-modified reprogramming protein to the subject, wherein the protein transduction reagent is non-covalently bound to the reprogramming protein and wherein the protein transduction reagent comprises a cation reagent and a lipid. According to aspects, such methods provide delivery of protein-transduction reagent-modified reprogramming proteins to cancer cells, such as tumor cells, as well as diseased cells of diseased tissues and provide in vivo conversion of diseased cells into normal cells via protein-induced in situ cell reprogramming without administration of nucleic acids to the subject.