Metastatic spread of cancer cells from the primary tumors to distant vital organs, such as lung, liver, brain, and bone, is responsible for the majority of cancer-related deaths. Cancer stem cells are likely to play essential roles in the metastatic spread of primary tumors because of their self-renewal capability and their potential to give rise to differentiated progenies that can adapt to different target organ microenvironments. Investigating the metastatic behavior of cancer stem cells (CSCs) is critical for the development of more effective therapies to prevent or delay the progression of malignant diseases. Animal models have been developed to mimic the multistep process of metastasis to various target organs. In this chapter, I will describe several xenograft methods to introduce human breast cancer cells into nude mice in order to generate spontaneous and experimental metastases. Similar experimental approach can be applied to analyze the metastatic behavior of CSCs derived from other tumor types.
"It is believed that few cancer stem cells (CSC) initially have the capacity for tumorigenesis and cancer metastasis (Alix-Panabieres et al, 2008; Dirks, 2010). Kang (2009) disclosed the metastatic behaviour of CSCs derived from tumours. As a result, we have focused our studies on CSCs in BM. "
[Show abstract][Hide abstract] ABSTRACT: Background:
We previously reported that bone marrow (BM) was a homing site for gastric cancer (GC) cells leading to haematogenous metastases. There has been little study that microRNAs regulated pathways in malignant cells or host cells in BM, and thereby regulated the progression of GC.
Both microRNA microarray and gene expression microarray analyses of total RNA from BM were conducted, comparing five early and five advanced GC patients. We focused on miR-144-ZFX axis as a candidate BM regulator of GC progression and validated the origin of the microRNA expression in diverse cell fractions (EpCAM+CD45−, EpCAM−CD45+, and CD14+) by magnetic-activated cell sorting (MACS).
Quantitative reverse-transcriptase (RT)–PCR analysis validated diminished miR-144 expression in stage IV GC patients with respect to stage I GC patients (t-test, P=0.02), with an inverse correlation to ZFX (ANOVA, P<0.01). Luciferase reporter assays in five GC cell lines indicated their direct binding and validated by western blotting. Pre-miR144 treatment and the resultant repression of ZFX in GC cell lines moderately upregulated their susceptibility to 5-fluorouracil chemotherapy. In MACS-purified BM fractions, the level of miR-144 expression was significantly diminished in disseminated tumour cell fraction (P=0.0005). Diminished miR-144 expression in 93 cases of primary GC indicated poor prognosis.
We speculate that disseminated cancer cells could survive in BM when low expression of miR-144 permits upregulation of ZFX. The regulation of the miR-144-ZFX axis in cancer cells has a key role in the indicator of the progression of GC cases.
British Journal of Cancer 09/2012; 107(8):1345-53. DOI:10.1038/bjc.2012.326 · 4.84 Impact Factor
"X-ray radiography analysis of bone lesions was performed using procedures as described . For the orthotopic xenograft model, mammary fat pad injections and tumor size measurements were performed as described [16, 32]. "
[Show abstract][Hide abstract] ABSTRACT: Aneuploidy is commonly observed in breast cancer and is associated with poor prognosis. One frequent type of aneuploidy, hypertetraploidy, may derive from ploidy duplication of hyperdiploid cells. However, the pathological consequences of ploidy duplication in breast cancer progression have not been characterized. Here, we present an experimental system demonstrating spontaneous appearance of hypertetraploid cells from organ-specific metastatic variants of the MDA-MB-231 breast cancer cell line through ploidy duplication in vitro and in vivo. The hypertetraploid progenies showed increased metastatic potential to lung and brain, but not to bone, which may be partially explained by the distinct capillary structures in these organs that confer differential lodging advantages to tumor cells with enlarged size. Our results suggest a potential mechanistic link between ploidy duplication and enhancement of metastatic potentials, as was observed in previous clinical studies of breast cancer.
Cell Research 09/2010; 20(9):1012-22. DOI:10.1038/cr.2010.93 · 12.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Most solid tumors have now been reported to contain stem cell-like cells called cancer stem cells (CSCs). These cells are endowed with high tumorigenic capacity and may be the cells that drive tumor formation, maintain tumor homeostasis, and mediate tumor metastasis. Since these self-renewing cancer cells may be the sole population to develop a primary tumor, it is predicted that CSCs may also represent the lethal seeds of metastasis, as supported by a flurry of recent studies on the relationship between CSCs and metastasis. Herein, we summarize current knowledge of stem/progenitor cells and CSCs, especially in the context of normal human prostate and prostate cancer. We further update the recently gained knowledge on the involvement of CSCs in metastasis. We also discuss the fundamental influence of tumor microenvironment on the manifestation of CSCs and metastasis. Finally, we discuss the clinical implication of CSC-based therapy.
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