Project description:Background: The addition of the anti-HER2 antibody pertuzumab to trastuzumab/chemotherapy treatment in HER2+ breast cancer significantly improves clinical outcome. Concomitantly, the drug-antibody conjugate T-DM1 (trastuzumab-emantasine) has demonstrated efficacy, at least equal, to the combination of trastuzumab/chemotherapy. Scientific, economic and health challenges emerge from the clinical use of these novel anti-HER2 antibodies, aimed to identify new resistance mechanisms and to select the target breast cancer population. Objectives: (1) To identify primary resistance mechanisms to anti-HER2 antibodies trastuzumab, pertuzumab, and to the combined trastuzumab/pertuzumab or pertuzumab/T-DM1 therapy, (2) To identify acquired resistance mechanisms to anti-HER2 antibodies trastuzumab, pertuzumab, and to the combined trastuzumab/pertuzumab or pertuzumab/T-DM1 therapy, (3) To develop new combinations of anti-HER2 antibodies with other targeted therapies.
Project description:Estrogen receptor positive (ER+) breast cancers that develop resistance to therapies that target the ER are the most common cause of breast cancer death. Beyond mutations in ER, which occur in 25-30% of patients treated with aromatase inhibitors (AIs), our understanding of clinical mechanisms of resistance to ER-directed therapies remains incomplete. We identified activating HER2 mutations in metastatic biopsies from eight patients with ER+ metastatic breast cancer who had developed resistance to ER-directed agents, including AIs, tamoxifen, and fulvestrant. Examination of treatment-naïve primary tumors in five patients revealed no evidence of pre-existing mutations in four of five patients, suggesting that these mutations were acquired under the selective pressure of ER-directed therapy. These mutations were mutually exclusive with ER mutations, suggesting a distinct mechanism of acquired resistance to ER-directed therapies. In vitro analysis confirmed that these mutations conferred estrogen independence. In addition, and in contrast to ER mutations, these mutations resulted in resistance to tamoxifen, fulvestrant, and the CDK4/6 inhibitor palbociclib. Resistance was overcome by combining ER-directed therapy with the irreversible HER2 kinase inhibitor neratinib, highlighting an effective treatment strategy in these patients.
Project description:In a 3D coculture with stroma cells derived from breast cancer patients’ brain metastasis, HER2+ breast cancer cells were protected from HER2-targeted therapies, particularly the EGFR/HER2 small molecule inhibitor neratinib. To get insight into how this protection arises, ATAC-seq on coculture cells with or without neratinib as performed.
Project description:In a 3D coculture with stroma cells derived from breast cancer patients’ brain metastasis, HER2+ breast cancer cells were protected from HER2-targeted therapies, particularly the EGFR/HER2 small molecule inhibitor neratinib. To get insight into how this protection arises, a Synthetic Notch (SynNotch) reporter model allowed to study the effect of direct contact between stroma and cancer cells.