Project description:Inhibition of the HER2/ERBB2 receptor is a keystone to treating HER2-positive malignancies, particularly breast cancer, but a significant fraction of HER2-positive (HER2+) breast cancers recur or fail to respond. Anti-HER2 monoclonal antibodies, like trastuzumab or pertuzumab, and ATP active site inhibitors like lapatinib, commonly lack durability because of adaptive changes in the tumor leading to resistance. HER2+ cell line responses to inhibition with lapatinib were analyzed by RNAseq and ChIPseq to characterize transcriptional and epigenetic changes. Motif analysis of lapatinib-responsive genomic regions implicated the pioneer transcription factor FOXA1 as a mediator of adaptive responses. Lapatinib in combination with FOXA1 depletion led to dysregulation of enhancers, impaired adaptive upregulation of HER3, and decreased proliferation. HER2-directed therapy using clinically relevant drugs (trastuzumab with or without lapatinib or pertuzumab) in a 7-day clinical trial designed to examine early pharmacodynamic response to antibody-based anti-HER2 therapy showed reduced FOXA1 expression was coincident with decreased HER2 and HER3 levels, decreased proliferation gene signatures, and increased immune gene signatures. This highlights the importance of the immune response to anti-HER2 antibodies and suggests that inhibiting FOXA1-mediated adaptive responses in combination with HER2 targeting is a potential therapeutic strategy.
Project description:Inhibition of the HER2/ERBB2 receptor is a keystone to treating HER2-positive malignancies, particularly breast cancer, but a significant fraction of HER2-positive (HER2+) breast cancers recur or fail to respond. Anti-HER2 monoclonal antibodies, like trastuzumab or pertuzumab, and ATP active site inhibitors like lapatinib, commonly lack durability because of adaptive changes in the tumor leading to resistance. HER2-directed therapy using clinically relevant drugs (trastuzumab with or without lapatinib or pertuzumab) in a 7-day clinical trial (ClinicalTrials.gov Identifier: NCT01875666, LCCC1214) designed to examine early pharmacodynamic response to antibody-based anti-HER2 therapy showed reduced FOXA1 transcription factor expression was coincident with decreased HER2 and HER3 levels, decreased proliferation gene signatures, and increased immune gene signatures. Patient samples from this trial, when sufficient material was available, were also subjected to kinase enrichment using multiplexed kinase inhibitor bead affinity chromatography and LC-MS/MS. Strongly responsive transcriptional responses observed in a subset of patients corresponded to decreased binding of CDK1 and DDR1 by our proteomic approach. Taken together, our results highlight the importance of the immune response to anti-HER2 antibodies and suggests that inhibiting FOXA1-mediated adaptive responses in combination with HER2 targeting is a potential therapeutic strategy.
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:Adaptive responses to targeted therapy in HER2-positive breast cancer (RNAseq) - TBCRC 036 / LCCC1214 / ClinicalTrials.gov Identifier: NCT01875666
Project description:Trastuzumab, a humanized monoclonal antibody directed to the HER2 protein, is the standard-of-care treatment for patients with HER2 positive breast cancer, reducing the risk of relapse and death in patients. Nonetheless, some patients do not benefit from this treatment, underscoring the need to identify patients for whom chemotherapy + trastuzumab is adequate versus patients requiring additional drugs. The series comprised 24 incisional biopsies of breast carcinomas derived from patients that received neoadjuvant trastuzumab based therapy. Gene expression profiling was performed using RNA from frozen core biopsies from 24 patients with primary HER2-positive (HER2+) tumors treated with neoadjuvant chemotherapy and trastuzumab.
Project description:Tumor-initiating cells (TICs) play a critical role in glioblastoma (GBM) maintenance being responsible for its heterogeneity and resistance to standard therapy. A step toward clinical translation includes GBM TIC targeting. Among the molecules tested for GBM treatment, are those targeting epigenetic modifiers. By using patient-derived TICs and xenograft orthotopic models, we identified Lysine-specific histone demethylase 1A (LSD1) as a potentially druggable target in GBM. LSD1-directed therapy by means of the selective, orally bioavailable and brain penetrant inhibitor DDP_38003 effectively impairs growth, stem-like features and tumorigenic potential of GBM TICs. Our findings point to LSD1 as a positive regulator of Activating Transcription Factor 4 (ATF4)-dependent response in all stress conditions arising during tumor growth and therapy. Thus, through the downregulation of either ATF4 and its adaptive genes, LSD1 targeting is likely a promising strategy to hit GBM TICs by counteracting the ATF4-mediated adaptation to stress.
Project description:Tumor-initiating cells (TICs) play a critical role in glioblastoma (GBM) maintenance being responsible for its heterogeneity and resistance to standard therapy. A step toward clinical translation includes GBM TIC targeting. Among the molecules tested for GBM treatment, are those targeting epigenetic modifiers. By using patient-derived TICs and xenograft orthotopic models, we identified Lysine-specific histone demethylase 1A (LSD1) as a potentially druggable target in GBM. LSD1-directed therapy by means of the selective, orally bioavailable and brain penetrant inhibitor DDP_38003 effectively impairs growth, stem-like features and tumorigenic potential of GBM TICs. Our findings point to LSD1 as a positive regulator of Activating Transcription Factor 4 (ATF4)-dependent response in all stress conditions arising during tumor growth and therapy. Thus, through the downregulation of either ATF4 and its adaptive genes, LSD1 targeting is likely a promising strategy to hit GBM TICs by counteracting the ATF4-mediated adaptation to stress.
Project description:Tumor-initiating cells (TICs) play a critical role in glioblastoma (GBM) maintenance being responsible for its heterogeneity and resistance to standard therapy. A step toward clinical translation includes GBM TIC targeting. Among the molecules tested for GBM treatment, are those targeting epigenetic modifiers. By using patient-derived TICs and xenograft orthotopic models, we identified Lysine-specific histone demethylase 1A (LSD1) as a potentially druggable target in GBM. LSD1-directed therapy by means of the selective, orally bioavailable and brain penetrant inhibitor DDP_38003 effectively impairs growth, stem-like features and tumorigenic potential of GBM TICs. Our findings point to LSD1 as a positive regulator of Activating Transcription Factor 4 (ATF4)-dependent response in all stress conditions arising during tumor growth and therapy. Thus, through the downregulation of either ATF4 and its adaptive genes, LSD1 targeting is likely a promising strategy to hit GBM TICs by counteracting the ATF4-mediated adaptation to stress.