ABSTRACT: Patient-derived xenografts of HER2-positive breast cancer brain metastases facilitate discovery of a therapeutic strategy yielding durable remissions
Project description:Patient-derived xenografts of HER2-positive breast cancer brain metastases facilitate discovery of a therapeutic strategy yielding durable remissions
Project description:Breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. To overcome these limitations, we propagated a cohort of human breast tumors grown in the epithelium-free mammary fat pad of SCID/Beige and NOD/SCID/IL2γ-receptor null (NSG) mice, under a series of transplant conditions. Both models yielded stably transplantable xenografts at comparably high rates (~23% and ~19%, respectively). Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 32 stably transplantable xenograft lines were established, representing unique 25 patients. Most tumors yielding xenografts were “triple-negative” (ER-PR-HER2+) (n=19). However, we established lines from three ER-PR-HER2+ tumors, one ER+PR-HER2-, one ER+PR+HER2- and one “triple-positive” (ER+PR+HER2+) tumor. Serially passaged xenografts show biological consistency with the tumor of origin, are phenotypic stability across multiple transplant generations at the histological, transcriptomic, proteomic, and genomic levels, and show comparable treatment responses. Xenografts representing 12 patients, including two ER+ lines, showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource for preclinical studies investigating treatment response and metastasis. The study was designed to determine how stable patient-derived xenografts are across multiple transplant generations in mice, and to determine how closely xenografts established with pre-treatment samples cluster with xenografts established with post-treatment samples. Overall, pre-treatment and post-treatment samples derived from the same patient cluster together, and multiple transplant generations of xenografts derived from an individual patient cluster together.
Project description:Breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. To overcome these limitations, we propagated a cohort of human breast tumors grown in the epithelium-free mammary fat pad of SCID/Beige and NOD/SCID/IL2γ-receptor null (NSG) mice, under a series of transplant conditions. Both models yielded stably transplantable xenografts at comparably high rates (~23% and ~19%, respectively). Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 32 stably transplantable xenograft lines were established, representing unique 25 patients. Most tumors yielding xenografts were “triple-negative” (ER-PR-HER2+) (n=19). However, we established lines from three ER-PR-HER2+ tumors, one ER+PR-HER2-, one ER+PR+HER2- and one “triple-positive” (ER+PR+HER2+) tumor. Serially passaged xenografts show biological consistency with the tumor of origin, are phenotypic stability across multiple transplant generations at the histological, transcriptomic, proteomic, and genomic levels, and show comparable treatment responses. Xenografts representing 12 patients, including two ER+ lines, showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource for preclinical studies investigating treatment response and metastasis.
Project description:Translational breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. In an effort to overcome these limitations, we propagated a cohort of human breast tumors grown in the mammary fat pad of SCID/Beige and NOD/SCID/IL2?-receptor null (NSG) two relatively new immunocompromised mouse models, under a series of transplant conditions. Both models yielded stably transplantable xenografts relatively high rates compared with previously available immunocompromised mice. Xenograft lines were established directly from breast cancer patient samples, without intervening culture in vitro, using the epithelium-free mammary fat pad as the transplantation site. Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 35 stably transplantable xenograft lines representing 27 patients were established, using pre-treatment, mid-treatment, and/or post-treatment samples. Most patients yielding xenografts were “triple-negative” (ER-PR-HER2-) (n=21). However, we were able to establish lines from three ER-PR-HER2+ patients, one ER+PR-HER2-, one ER+PR+HER2- and one “triple-positive” (ER+PR+HER2+) patient. Serially passaged xenografts show biological consistency with the tumor of origin at the histopathology level, and remarkable stability across multiple transplant generations at the genomic, transcriptomic, and proteomic levels. Of the 27 patients represented, xenografts derived from 13 patients showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource, and should prove useful for preclinical evaluation of experimental therapeutics. reference x sample
Project description:Combined targeting CDK4/6 and HER2 signaling in orthotopic patient-derived xenografts of HER2-positive breast cancer brain metastases
Project description:Combined targeting CDK4/6 and HER2 signaling in orthotopic patient-derived xenografts of HER2-positive breast cancer brain metastases
Project description:Translational breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. In an effort to overcome these limitations, we propagated a cohort of human breast tumors grown in the mammary fat pad of SCID/Beige and NOD/SCID/IL2?-receptor null (NSG) two relatively new immunocompromised mouse models, under a series of transplant conditions. Both models yielded stably transplantable xenografts relatively high rates compared with previously available immunocompromised mice. Xenograft lines were established directly from breast cancer patient samples, without intervening culture in vitro, using the epithelium-free mammary fat pad as the transplantation site. Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 35 stably transplantable xenograft lines representing 27 patients were established, using pre-treatment, mid-treatment, and/or post-treatment samples. Most patients yielding xenografts were “triple-negative” (ER-PR-HER2-) (n=21). However, we were able to establish lines from three ER-PR-HER2+ patients, one ER+PR-HER2-, one ER+PR+HER2- and one “triple-positive” (ER+PR+HER2+) patient. Serially passaged xenografts show biological consistency with the tumor of origin at the histopathology level, and remarkable stability across multiple transplant generations at the genomic, transcriptomic, and proteomic levels. Of the 27 patients represented, xenografts derived from 13 patients showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource, and should prove useful for preclinical evaluation of experimental therapeutics.
Project description:Background: Central nervous system (CNS) metastases represent a major problem in the treatment of HER2-positive breast cancer due to the disappointing efficacy of HER2-targeted therapies in the brain microenvironment. The antibody-drug conjugate ado-trastuzumab emtansine (T-DM1) has shown efficacy in trastuzumab-resistant systemic breast cancer. Here, we tested the hypothesis that T-DM1 could overcome trastuzumab resistance in preclinical models of brain metastases. Methods: We treated mice bearing BT474 or MDA-MB-361 tumors in the CNS (N=9-11 per group), or cancer cells grown in organotypic brain slice cultures with trastuzumab or T-DM1 at equivalent or equipotent doses. Using intravital imaging, molecular techniques and histological analysis we determined tumor growth, mouse survival, cancer cell apoptosis and proliferation, tumor drug distribution, and HER2 signaling. All statistical tests were two-sided. Results: T-DM1 significantly delayed the growth of HER2-positive breast cancer brain metastases compared to trastuzumab. These findings were consistent between HER2-driven and PI3K-driven tumors. The activity of T-DM1 resulted in a striking survival benefit (median survival for BT474 tumors: 28d for trastuzumab vs 112d for T-DM1, HR=6.2, 95% CI=6.1 to 85.84; P<.001). No difference in drug distribution and HER2-signaling was revealed between the two groups. However, T-DM1 led to a significant increase in tumor cell apoptosis (One-way ANOVA for ApopTag, p<.001), which was associated with mitotic catastrophe. Conclusions: T-DM1 can overcome resistance to trastuzumab therapy in HER2-driven and PI3K-driven breast cancer brain lesions due to the cytotoxicity of the DM1 component. Clinical investigation of T-DM1 for patients with CNS metastases from HER2-positive breast cancer is warranted. Comparison of trastuzumab (n=4) and TDM-1 (n=4) treated BT-474 human breast carcinoma cells growing in murine brain
Project description:<p>We have developed orthotopic patient-derived xenograft models of HER2 positive breast cancer metastasized into the brain of patients to test novel therapeutic strategies. In this study, we identified a novel combinatorial therapeutic strategy that has resulted in a durable remission and markedly increased overall survival in majority of patient-derived xenograft (PDX) models tested. We performed whole exome sequencing analysis of these PDX tumors and their matched blood and patient samples to investigate drug sensitive and resistance mechanisms. Our sequencing data revealed an interesting association of genotyping and phenotyping with tumors responses to drug treatment.</p>
Project description:Brain metastases from breast and other cancers constitute an important part of therapeutic failures and are associated with severe morbidity and mortality. Here, we have examined histopathological data and generated gene expression data in two independent cohorts of primary tumors from HER2-positive advanced breast cancer patients. We report that the combination of estrogen receptor (ER) negativity and expression of a novel 13-gene signature identify a subset of patients with rapid (median, 31 and 41 months in discovery and validation cohorts, respectively) versus slower (median, 66 months and 77 months in discovery and validation cohorts, respectively) development of brain metastases (P<0.0001). The 13-gene signature also predicted rapid brain metastasis formation within the ER-negative subset of patients (P=0.014). Interestingly, three of the genes in the signature (RAD51, BARD1, FANCG) function in DNA double strand break repair. Overexpression of RAD51 in immortal MCF-10A breast epithelial cells altered their three-dimensional acinar morphology to increase the percentage of invasive structures by 6.5 fold, in the presence or absence of HER2 overexpression. In summary, ER negativity and a novel 13-gene signature may have the potential to identify subpopulations at highest immediate risk for the development of brain metastases in HER2-positive advanced breast cancer. Our results also suggest that RAD51, found in the 13-gene signature, may promote aggressiveness in breast epithelial cells. These data may be useful in the design of brain metastasis preventive trials and may prompt new treatment strategies Median normalized data provided