Project description:All-trans retinoic acid (atRA) regulates gene expression and is used to treat acute promyelocytic leukemia. Attempts to use atRA for breast cancer treatment without a stratification strategy have resulted in limited overall effectiveness. To identify biomarkers for the treatment of triple-negative breast cancer (TNBC) with atRA, we characterized the effects of atRA on the tumor growth of 13 TNBC cell lines. This resulted in a range of tumor growth effects that was not predictable based on the levels of retinoid signaling molecules and transcriptional responses that were mostly independent of retinoic acid response elements. Given the importance of DNA methylation in regulating gene expression, we hypothesized that differential DNA methylation could predict the response of TNBCs to atRA. We identified over 1400 CpG sites that were differentially methylated between atRA resistant and sensitive cell lines. These CpG sites predicted the response of four TNBC patient-derived xenografts to atRA treatment and we utilized these xenografts to refine the profile to 6 CpGs. We identify as many as 17% of TNBC patients who could benefit from atRA treatment. These data illustrate that differential DNA methylation of specific sites may predict the response of patient tumors to atRA treatment.
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:Patient derived xenografts (PDX) were created from two triple-negative breast cancers (PDX-110 and PDX-332) taken at the time of surgery from drug-naive patients. Freshly sorted epithelial cells were profiled by single-cell RNA-seq (scRNA-seq) using a 10X Genomics Chromium System.
Project description:Triple negative breast cancer (TNBC) is an aggressive subtype that lack targeted clinical therapies. In addition, TNBC is heterogeneous and was recently further sub-classified into seven TNBC subtypes that displayed unique gene expression patterns. To develop therapeutic treatment regimens, we established seven patient-derived xenograft models from TNBC tumors. These xenograft models not only retained the histology and clinical markers of the corresponding patient tumors, but also bearing the same mutations and deletions identified in the patient tumors. Moreover, as part of evaluation of these models, we performed microarrays on the xenograft tumors to assess their TNBC subtypes. After obtaining IRB-approved informed written patient consent, breast cancer tissues were obtained fresh from Stanford Hospital and transplanted into the number 2 mammary fat pads of female NOD SCID mice (NOD.CB17-Prkdcscid/J, Jackson Laboratory West, Sacramento, CA, USA). Mice were maintained in pathogen-free animal housing. The established xenografts were subsequently passaged from mouse to mouse. Xenograft tumor tissues were frozen on dry ice for RNA isolation and microarray analysis.
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:Transcriptomic profiling of triple-negative breast cancer (TNBC) patient-derived xenografts (PDX) sensitive and resistant to docetaxel.