Article

Biomarkers of Residual Disease, Disseminated Tumor Cells, and Metastases in the MMTV-PyMT Breast Cancer Model

University College London, United Kingdom
PLoS ONE (Impact Factor: 3.53). 03/2013; 8(3):e58183. DOI: 10.1371/journal.pone.0058183
Source: PubMed

ABSTRACT Cancer metastases arise in part from disseminated tumor cells originating from the primary tumor and from residual disease persisting after therapy. The identification of biomarkers on micro-metastases, disseminated tumors, and residual disease may yield novel tools for early detection and treatment of these disease states prior to their development into metastases and recurrent tumors. Here we describe the molecular profiling of disseminated tumor cells in lungs, lung metastases, and residual tumor cells in the MMTV-PyMT breast cancer model. MMTV-PyMT mice were bred with actin-GFP mice, and focal hyperplastic lesions from pubertal MMTV-PyMT;actin-GFP mice were orthotopically transplanted into FVB/n mice to track single tumor foci. Tumor-bearing mice were treated with TAC chemotherapy (docetaxel, doxorubicin, cyclophosphamide), and residual and relapsed tumor cells were sorted and profiled by mRNA microarray analysis. Data analysis revealed enrichment of the Jak/Stat pathway, Notch pathway, and epigenetic regulators in residual tumors. Stat1 was significantly up-regulated in a DNA-damage-resistant population of residual tumor cells, and a pre-existing Stat1 sub-population was identified in untreated tumors. Tumor cells from adenomas, carcinomas, lung disseminated tumor cells, and lung metastases were also sorted from MMTV-PyMT transplant mice and profiled by mRNA microarray. Whereas disseminated tumors cells appeared similar to carcinoma cells at the mRNA level, lung metastases were genotypically very different from disseminated cells and primary tumors. Lung metastases were enriched for a number of chromatin-modifying genes and stem cell-associated genes. Histone analysis of H3K4 and H3K9 suggested that lung metastases had been reprogrammed during malignant progression. These data identify novel biomarkers of residual tumor cells and disseminated tumor cells and implicate pathways that may mediate metastasis formation and tumor relapse after therapy.

0 Followers
 · 
129 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objectives MET is a receptor present in the membrane of NSCLC cells and is known to promote cell proliferation, survival and migration. MET gene copy number is a common genetic alteration and inhibition o MET emerges as a promising targeted therapy in NSCLC. Here we aim to combine in a meta-analysis, data on the effect of high MET gene copy number on the overall survival of patients with resected NSCLC. Methods Two independent investigators applied parallel search strategies with the terms “MET AND lung cancer”, “MET AND NSCLC”, “MET gene copy number AND prognosis” in PubMed through January 2014. We selected the studies that investigated the association of MET gene copy number with survival, in patients who received surgery. Results Among 1096 titles that were identified in the initial search, we retrieved 9 studies on retrospective cohorts with adequate retrievable data regarding the prognostic impact of MET gene copy number on the survival of patients with NSCLC. Out of those, 6 used FISH and the remaining 3 used RT PCR to assess the MET gene copy number in the primary tumor. We calculated the I2 statistic to assess heterogeneity (I2 = 72%). MET gene copy number predicted worse overall survival when all studies were combined in a random effects model (HR = 1.78, 95% CI 1.22–2.60). When only the studies that had at least 50% of adenocarcinoma patients in their populations were included, the effect was significant (five studies, HR 1.55, 95% CI 1.23–1.94). This was not true when we included only the studies with no more than 50% of the patients having adenocarcinoma histology (four studies HR 2.18, 95% CI 0.97–4.90). Conclusions Higher MET gene copy number in the primary tumor at the time of diagnosis predicts worse outcome in patients with NSCLC. This prognostic impact may be adenocarcinoma histology specific.
    PLoS ONE 09/2014; 9(9):e107677. DOI:10.1371/journal.pone.0107677 · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recent studies in patients with breast cancer suggest the immune microenvironment influences response to therapy. We aimed to evaluate the relationship between growth rates of tumors in common spontaneous mammary tumor models and immune biomarkers evaluated in the tumor and blood. TgMMTV-neu and C3(1)-Tag transgenic mice were followed longitudinally from birth, and MPA-DMBA-treated mice from the time of carcinogen administration, for the development of mammary tumors. Tumor-infiltrating CD4(+) and CD8(+) T-cells, FOXP3(+) T-regulatory cells, and myeloid-derived suppressor cells were assessed by flow cytometry. Serum cytokines were evaluated in subsets of mice. Fine needle aspirates of tumors were collected and RNA was isolated to determine levels of immune and proliferation markers. Age of tumor onset and kinetics of tumor growth were significantly different among the models. Mammary tumors from TgMMTV-neu contained a lower CD8/CD4 ratio than that of other models (p < 0.05). MPA-DMBA-induced tumors contained a higher percentage of FOXP3(+) CD4(+) T-cells (p < 0.01) and MDSC (p < 0.001) compared with the other models. Individuals with significantly slower tumor growth demonstrated higher levels of Type I serum cytokines prior to the development of lesions compared to those with rapid tumor growth. Moreover, the tumors of animals with more rapid tumor growth demonstrated a significant increase in the expression of genes associated with Type II immunity than those with slower-progressing tumors. These data provide a foundation for the development of in vivo models to explore the relationship between endogenous immunity and response to standard therapies for breast cancer.
    Breast Cancer Research and Treatment 11/2014; DOI:10.1007/s10549-014-3199-9 · 4.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: While the E2F transcription factors have a clearly defined role in cell cycle control, recent work has uncovered new functions. Using genomic signature methods, we predicted a role for the activator E2F transcription factors in the MMTV-PyMT mouse model of metastatic breast cancer. To genetically test the hypothesis that the E2Fs function to regulate tumor development and metastasis, we interbred MMTV-PyMT mice with the knockouts of E2F1, E2F2 and E2F3. With the ablation of individual E2Fs we noted alteration of tumor latency, histology, and vasculature. Interestingly, we noted a striking reduction in metastatic capacity and circulating tumor cells in both E2F1 and E2F2 knockout backgrounds. Investigating E2F target genes that mediate metastasis, we found that E2F loss led to decreased levels of Vegfa, Bmp4, Cyr61, Nupr1, Plod 2, P4ha1, Adamts1, Lgals3, and Angpt2. These gene expression changes indicate that the E2Fs control expression of genes critical to angiogenesis, remodeling of the extracellular matrix, tumor cell survival and tumor cell interactions with vascular endothelial cells to facilitate metastasis to the lungs. Taken together, these results reveal that the E2F transcription factors have key roles in mediating tumor development and metastasis in addition to their well characterized roles in cell cycle control.
    Molecular and Cellular Biology 06/2014; 34(17). DOI:10.1128/MCB.00737-14 · 5.04 Impact Factor

Full-text (3 Sources)

Download
35 Downloads
Available from
Jun 6, 2014