Disclosed herein is the discovery that administration of the NRIF3 family of transcriptional coregulators (NRIF3 and related molecules) to breast cancer cells induce rapid and profound apoptosis (nearly 100% cell death within 24 h). A novel death domain (DD1) was mapped to a short 30 amino acid region common to all members of the NRIF3 family. Two other death domains (DD2 and DD3) were also found to have effective breast cancer killing activities. Mechanistic studies showed that DD1-induced apoptosis occurred through a novel caspase-2 mediated pathway that involved mitochondria membrane permeabilization but did not require other caspases. Interestingly, cytotoxicity of NRIF3 related molecules was cell-type specific, as they selectively killed breast cancer or related cells but not other examined cells of different origins, suggesting the presence in breast cancer cells of a specific death switch that can be selectively triggered by NRIF3 and related molecules. Also disclosed are strategies utilizing NRIF3 related molecules and/or targeting this death switch for the development of novel and more selective therapeutics against breast cancer.
