Provided herein are methods for inducing growth arrest or apoptosis in cancer cells in a subject. Further provided are methods of inhibiting or treating metastasis of a cancer cell in a subject. The methods involve administering to the subject an antibody conjugate containing an antibody, variant thereof, or functional fragment thereof having binding specificity of the antibody as produced by the hybridoma having ATCC accession number PTA 2439 and a biologically active molecule. The antibody (e.g., mAb 3E10) variant or functional fragment thereof provides for the in vivo transduction of the conjugate to the nucleus of mammalian cells, where the conjugated biologically active molecule may exert its effect. In particular embodiments, the antibody conjugate comprises a single chain Fv fragment of an antibody having the binding specificity of mAb 3E10 produced by ATCC PTA 2439, conjugated to p53.