Project description:Gene Expression Profiling of a Mouse Xenograft Model of â??Triple-Negativeâ?? Breast Cancer Brain Metastases With and Without Vorinostat Treatment. Purpose: As chemotherapy and molecular therapy improve the systemic survival of breast cancer patients, the incidence of brain metastases increases. Few therapeutic strategies exist for the treatment of brain metastases because the blood-brain barrier severely limits drug access. We report the pharmacokinetic, efficacy, and mechanism of action studies for the histone deactylase inhibitor vorinostat (suberoylanilide hydroxamic acid) in a preclinical model of brain metastasis of triple-negative breast cancer. Experimental Design: The 231-BR brain trophic subline of the MDA-MB-231 human breast cancer cell line was injected into immunocompromised mice for pharmacokinetic and metastasis studies. Pharmacodynamic studies compared histone acetylation, apoptosis, proliferation, and DNA damage in vitro and in vivo. Results: Following systemic administration, uptake of [14C]vorinostat was significant into normal rodent brain and accumulation was up to 3-fold higher in a proportion of metastases formed by 231-BR cells. Vorinostat prevented the development of 231-BR micrometastases by 28% (P = 0.017) and large metastases by 62% (P < 0.0001) compared with vehicle-treated mice when treatment was initiated on day 3 post-injection. The inhibitory activity of vorinostat as a single agent was linked to a novel function in vivo: induction of DNA double-strand breaks associated with the down-regulation of the DNA repair gene Rad52. Conclusions: We report the first preclinical data for the prevention of brain metastasis of triple-negative breast cancer. Vorinostat is brain permeable and can prevent the formation of brain metastases by 62%. Its mechanism of action involves the induction of DNA double-strand breaks, suggesting rational combinations with DNA active drugs or radiation. Experiment Overall Design: We performed gene expression profiling on metastases from vehicle- or vorinostat-treated mice to determine if alterations in gene expression were observable that were consistent with the phenotypes observed. Brain metastases from five vehicle-treated mice and six 150 mg/kg vorinostat-treated mice were procured by laser capture microdissection. RNA was extracted from the captured tumor cells from each brain and two rounds of linear amplification was done. The amplified RNA from each mouse was processed separately through microarray hybridization and analysis.

Project description:BACKGROUND: While many authorities theorize that cancer vaccines are too weak to be widely effective, there are quite a few reports with clearly demonstrated, significant clinical benefit in some patients. The literature of cellular cancer immunotherapies shows that 53% (78/147) of phase II studies showed evidence of clinical activity. While not all reached their primary endpoints, 75% (12/16) of phase III studies had positive data. SV-BR-1-GM, derived from a patient with grade 2 (moderately differentiated) breast cancer, is a GM-CSF-secreting breast cancer cell line with properties of antigen-presenting cells we established. METHODS: We report detailed molecular and clinical findings from an open-label phase I, single-arm pilot study in breast (3 subjects) and ovarian (1 subject) cancer with irradiated SV-BR-1-GM cells (ClinicalTrials.gov Identifier NCT00095862). Inoculations of SV-BR-1-GM were preceded by low-dose cyclophosphamide and followed by injections of interferon-alpha2b into the SV-BR-1-GM inoculation sites. We assessed both cellular (delayed-type hypersensitivity (DTH) reactions) and humoral (anti-SV-BR-1 antibody) immune responses and conducted molecular analyses on patient blood cells and SV-BR-1-GM cells. RESULTS: Treatment was generally safe and well tolerated. Immune responses were elicited universally. Overall survival was more than 33 months for three of the four patients. As previously reported, one patient (Subject A002, with grade 2 breast cancer) had regression of metastases in lung, breast and soft tissue within 2 months of treatment initiation. At later relapse, with multiple metastases including several in the brain, rapid tumor response was again seen, including complete regression of CNS metastases. Consistent with a role of Class II HLA in contributing to SV-BR-1-GM’s mechanism of action, Subject A002 allele-matched SV-BR-1-GM at the HLA-DRB1 and HLA-DRB3 loci. Only the HLA-DRB1 alleles were clearly expressed in SV-BR-1-GM cells. However, interferon-gamma (possibly also present in situ) upregulated both HLA-DRB1 and HLA-DRB3 to substantial levels. Gene expression data supports the hypothesis that SV-BR-1-GM cells have retained some of the original breast cancer’s grade 2 character. CONCLUSIONS: We describe a whole-cell immunotherapy regimen with remarkable rapidity of response and a speedy rescue response, including complete resolution of CNS metastases after relapse. Class II HLA matches might be critical for SV-BR-1-GM’s therapeutic potential.

Project description:Breast cancer metastasizes to bone, visceral organs, and/or brain depending on the subtypes. Various cell line models have been used to develop gene expression signatures unique to cancer cells that have metastasized to specific organs, although these efforts were not in a uniform setting. In this study, we compared gene expression pattern in MDA-MB-231 cells and its mammary fat pad tumor (TMD-231), lung metastasis (LMD-231), bone metastasis (BMD-231), adrenal metastasis (ADMD-231) and brain metastasis (231-BR) variants grown under the same growth condition. When gene expression differences between metasteses (p value of <0.01) were compared, 231-BR cells showed the highest gene expression difference (633 genes) followed by ADMD-231 (196 genes), LMD-231 (79 genes), and BMD-231 cells (60 genes) compared with other metastatic cells. 231-BR cells specifically overexpressed neuronal transmembrane proteins SLITRK2, TMEM47, and LYPD1 by more than five fold compared with cells isolated from other sites of metastasis. Ingenuity pathway analysis of differentially expressed genes revealed activation of pathways that would enable cancer cells to adapt to organs of metastasis such as drug detoxification/oxidative stress response/semaphorin neuronal pathway in 231-BR cells, Notch/orphan nuclear receptor signals involved in steroidogenesis in ADMD-231, acute phase response in LMD-231, and cytokine/hematopoietic stem cell signaling in BMD-231 cells. Only NF-κB signaling pathway activation was common to all metastatic cells except BMD-231.To test this possibility, we compared gene expression pattern in MDA-MB-231 cells and its mammary fat pad tumor (TMD-231), lung-metastasis (LMD-231), bone-metastasis (BMD-231), adrenal-metastasis (ADMD-231) and brain-metastasis (231-BR) variants. Between metastatic cells, 231-BR cells showed the highest gene expression difference followed by ADMD-231, LMD-231, and BMD-231 cells. 231-BR cells specifically overexpressed neuronal transmembrane proteins SLITRK2, TMEM47, and LYPD1. pathways that would enable cancer cells to adapt to organs of metastasis such as drug detoxification/oxidative stress response/semaphorin neuronal pathway in 231-BR cells, Notch/orphan nuclear receptor signals involved in steroidogenesis in ADMD-231, acute phase response in LMD-231, and cytokine/hematopoietic stem cell signaling in BMD-231 cells. Only NF-κB signaling pathway activation was common to all metastatic cells except BMD-231.

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Expression data for High and Low permeable brain metastases in 231-BR mouse model

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