Triple Negative Breast Cancer (TNBC) accounts for 15-25% of breast cancers. TNBC is well known for its aggressive clinical behavior and early peak of recurrence. Due to the lack of good therapeutic targets, TNBC represents the specific subtype of breast cancer with worst prognosis. Therefore, there remains the urgent question to be addressed: Can we identity important biological features that serve as high value targets for the development of novel treatment modalities for TNBC? This line of research carries significant social and economic importance. Hypoxia is a characteristic of solid tumor, which contributes to radiation and chemotherapy resistance. One important feature of tumor cells is that they sense the oxygen tension and rewire their signaling pathway to survive under harsh living conditions. EglN2 prolyl hydroxylase serves as an important oxygen sensor. In this proposal, we presented some preliminary data in the TNBC cell lines that getting rid of EglN2 could decrease TNBC tumor growth and invasion. We propose to obtain primary tumors from TNBC patients, implant them into mice and treat them with siRNA nanoparticles that deplete EglN2, which will be used to test the efficacy of targeting EglN2 in a patient relevant system. In addition, we will study mechanistically how EglN2 protein stability is regulated by FBW7 E3 ligase complex. Furthermore, we will implement a novel screening for EglN2 specific inhibitors, which will motivate testing the effect of these potential inhibitors on TNBC tumorigenesis. Successful completion of proposed research will open new therapeutic avenues in treating TNBC.