SETD4 marks Quiescent Cancer Stem Cells with Chemoradiotherapy Resistance in Breast Cancer of MMTV-PyMT Mouse
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ABSTRACT: We isolated quiescent CSCs using chemoradiotherapy resistance assays on tumors of MMTV-PyMT transgenic (specific breast cancer model) mice. We found that quiescent CSCs specifically expressed SETD4 without exception, and beyond activation exhibited high capacity of tumor-initiation in vivo and tumorsphere formation in vitro. Quiescent CSCs expressed high levels of ALDH1 and CD44 and low levels of CD24, that corresponds with their use as breast CSCs markers. Quiescent CSCs were showed to be resistant and able to survive under chemoradiotherapy treatment in either in vivo or in vitro models. Similarly, SETD4 overexpression caused cells extracted from tumors to exhibit clear chemoradiotherapy resistance. Transcriptomic analysis revealed that the molecular processes associated with cellular quiescence included those of DNA damage response and the Wnt/β-catenin signaling pathway. Together with our previous results, these findings showed that SETD4 marks quiescent CSCs and suggest that SETD4-marked quiescent CSCs could be used as key targets in clinical treatment for multiple cancers.
Project description:Tumor therapy mainly targets the tumor bulk, but tends to fail to eradicate the small resistant population of dormant cancer cells (DCCs) that enable relapse and/or metastasis beyond therapy. Using chemoradiotherapy resistant assay and SETD4 expression of a histone lysine methyltransferase, DCCs with high capacity of tumor-initiation and tumorsphere formation were isolated from three types of breast tumors. Exogenous DEK, a nuclear protein, activated the DCCs by binding to open chromatin which decreased SETD4, up-regulated the MYC and down-regulated the P53 signaling pathways. DEK-containing exosomes in blood highly correlate with tumor progress and exosomal DEK promotes tumor relapse and metastasis beyond chemoradiotherapy. Beyond activation, these formerly dormant cancer cells lost their chemoradiotherapy resistance. In treatment of DEK-containing exosomes plus chemoradiotherapy in mice, three types of breast tumors were eliminated without recurrence. Prior DCCs reactivation, as triggered by exogenous DEK may provide treatment options that eliminate both metastasis and recurrence potential.
Project description:Tumor therapy mainly targets the tumor bulk, but tends to fail to eradicate the small resistant population of dormant cancer cells (DCCs) that enable relapse and/or metastasis beyond therapy. Using chemoradiotherapy resistant assay and SETD4 expression of a histone lysine methyltransferase, DCCs with high capacity of tumor-initiation and tumorsphere formation were isolated from three types of breast tumors. Exogenous DEK, a nuclear protein, activated the DCCs by binding to open chromatin which decreased SETD4, up-regulated the MYC and down-regulated the P53 signaling pathways. DEK-containing exosomes in blood highly correlate with tumor progress and exosomal DEK promotes tumor relapse and metastasis beyond chemoradiotherapy. Beyond activation, these formerly dormant cancer cells lost their chemoradiotherapy resistance. In treatment of DEK-containing exosomes plus chemoradiotherapy in mice, three types of breast tumors were eliminated without recurrence. Prior DCCs reactivation, as triggered by exogenous DEK may provide treatment options that eliminate both metastasis and recurrence potential.
Project description:Tumor therapy mainly targets the tumor bulk, but tends to fail to eradicate the small resistant population of dormant cancer cells (DCCs) that enable relapse and/or metastasis beyond therapy. Using chemoradiotherapy resistant assay and SETD4 expression of a histone lysine methyltransferase, DCCs with high capacity of tumor-initiation and tumorsphere formation were isolated from three types of breast tumors. Exogenous DEK, a nuclear protein, activated the DCCs by binding to open chromatin which decreased SETD4, up-regulated the MYC and down-regulated the P53 signaling pathways. DEK-containing exosomes in blood highly correlate with tumor progress and exosomal DEK promotes tumor relapse and metastasis beyond chemoradiotherapy. Beyond activation, these formerly dormant cancer cells lost their chemoradiotherapy resistance. In treatment of DEK-containing exosomes plus chemoradiotherapy in mice, three types of breast tumors were eliminated without recurrence. Prior DCCs reactivation, as triggered by exogenous DEK may provide treatment options that eliminate both metastasis and recurrence potential.
Project description:Evidence of cancer immunosurveillance and immunoediting processes has been primarily demonstrated in mouse models of chemically induced oncogenesis. Although these models are very tractable, they are characterized by high mutational loads that represent a minority of human cancers. In this study, we sought to determine whether cancer immunosurveillance and immunoediting could be demonstrated in a more clinically relevant oncogene-induced model of carcinogenesis, the MMTV-PyMT (PyMT) mammary carcinoma model. This model system in the FVB/NJ strain background was previously used to demonstrate that adaptive immunity had no role in limiting primary cancer formation and in fact promoted metastasis, thus calling into question whether cancer immunosurveillance operated in preventing the development of breast cancer. Our current study in the C57BL/6 strain backgrounds provides a different conclusion, as we report here the existence of an adaptive immunosurveillance of PyMT mammary carcinomas using two independent models of immune deficiency. PyMT mice bred onto a Rag1-/- background or immune suppressed by chronic tacrolimus therapy both demonstrated accelerated development of mammary carcinomas. By generating a bank of cell lines from these animals, we further show that a subset of PyMT cell lines had delayed growth after transplantation into wild-type (WT) syngeneic, but not immune-deficient hosts. This reduced growth rate in immunocompetent animals was characterized by an increase in immune cell infiltration and tissue differentiation. Furthermore, loss of the immune cell infiltration that characterized immunoediting of slow growing cell lines, changed them into fast growing variants capable of progressing in the immunocompetent model. In conclusion, our study provides evidence that immunosurveillance and immunoediting of PyMT-derived cell lines modulate tumor progression in this oncogene-induced model of cancer.
Project description:Targeting early lesion in breast cancer is more therapeutically effective. We have previously identified an oncoprotein GT198 (PSMC3IP) in human breast cancer. Here we investigated GT198 in MMTV-PyMT mouse mammary gland tumors and found that GT198 is a shared early lesion in both species. Similar to human breast cancer even before a tumor appears, cytoplasmic GT198 is overexpressed in mouse tumor stroma including pericyte stem cells, descendent adipocytes, fibroblasts, and myoepithelial cells. Using recombinant GT198 protein as an antigen, we vaccinated MMTV-PyMT mice and found that the GT198 vaccine delayed mouse tumor growth and reduced lung metastasis. The antitumor effects were linearly correlated with vaccinated mouse serum titers of GT198 antibody, which recognized cell surface GT198 protein on viable tumor cells confirmed by FACS. Furthermore, GT198+ tumor cells isolated from MMTV-PyMT tumor induced faster tumor growths than GT198- cells when re-implanted into normal FVB/N mice. Together, this first study of GT198 vaccine in mouse showed its effectiveness in antitumor and anti-metastasis. The finding supports GT198 as a potential target in human immunotherapy since GT198 defect is shared in both human and mouse.
Project description:Elevated mitochondrial biogenesis and metabolism represent key features of breast cancer stem cells (CSCs), whose propagation is conducive to disease onset and progression. Therefore, interfering with mitochondria biology and function may be regarded as a useful approach to eradicate CSCs. Here, we used the breast cancer cell line MCF7 as a model system to interrogate how mitochondrial fission contributes to the development of mitochondrial dysfunction toward the inhibition of metabolic flux and stemness. We generated an isogenic MCF-7 cell line transduced with Mitochondrial Fission Factor (MCF7-MFF), which is primarily involved in mitochondrial fission. We evaluated the biochemical, molecular and functional properties of MCF7-MFF cells, as compared to control MCF7 cells transduced with the empty vector (MCF7-Control). We observed that MFF over-expression reduces both mitochondrial mass and activity, as evaluated using the mitochondrial probes MitroTracker Red and MitoTracker Orange, respectively. The analysis of metabolic flux using the Seahorse XFe96 revealed the inhibition of OXPHOS and glycolysis in MCF7-MFF cells, suggesting that increased mitochondrial fission may impair the biochemical properties of these organelles. Notably, CSCs activity, assessed by 3D-tumorsphere assays, was reduced in MCF7-MFF cells. A similar trend was observed for the activity of ALDH, a well-established marker of stemness. We conclude that enhanced mitochondrial fission may compromise CSCs propagation, through the impairment of mitochondrial function, possibly leading to a quiescent cell phenotype. Unbiased proteomic analysis revealed that proteins involved in mitochondrial dysfunction, oxidative stress-response, fatty acid metabolism and hypoxia signaling are among the most highly up-regulated in MCF7-MFF cells. Of note, integrated analysis of top regulatory networks obtained from unbiased proteomics in MCF7-MFF cells predicts that this cell phenotype activates signaling systems and effectors involved in the inhibition of cell survival and adhesion, together with the activation of specific breast cancer cell death programs. Overall, our study shows that unbalanced and abnormal activation of mitochondrial fission may drive the impairment of mitochondrial metabolic function, leading to inhibition of CSC propagation, and the activation of quiescence programs. Exploiting the potential of mitochondria to control pivotal events in tumor biology may, therefore, represent a useful tool to prevent disease progression.
Project description:Malignant breast cancer with complex molecular mechanisms of progression and metastasis remains a leading cause of death in women. To improve diagnosis and drug development, it is critical to identify panels of genes and molecular pathways involved in tumor progression and malignant transition. Using the PyMT mouse, a genetically engineered mouse model that has been widely used to study human breast cancer, we profiled and analyzed gene expression from four distinct stages of tumor progression (hyperplasia, adenoma/MIN, early carcinoma and late carcinoma) during which malignant transition occurs.We found remarkable expression similarity among the four stages, meaning genes altered in the later stages showed trace in the beginning of tumor progression. We identified a large number of differentially expressed genes in PyMT samples of all stages compared with normal mammary glands, enriched in cancer-related pathways. Using co-expression networks, we found panels of genes as signature modules with some hub genes that predict metastatic risk. Time-course analysis revealed genes with expression transition when shifting to malignant stages. These may provide additional insight into the molecular mechanisms beyond pathways.Thus, in this study, our various analyses with the PyMT mouse model shed new light on transcriptomic dynamics during breast cancer malignant progression.
Project description:BACKGROUND: Tetraspanins are transmembrane proteins that serve as scaffolds for multiprotein complexes containing, for example, integrins, growth factor receptors and matrix metalloproteases, and modify their functions in cell adhesion, migration and transmembrane signaling. CD151 is part of the tetraspanin family and it forms tight complexes with β1 and β4 integrins, both of which have been shown to be required for tumorigenesis and/or metastasis in transgenic mouse models of breast cancer. High levels of the tetraspanin CD151 have been linked to poor patient outcome in several human cancers including breast cancer. In addition, CD151 has been implicated as a promoter of tumor angiogenesis and metastasis in various model systems. METHODS: Here we investigated the effect of Cd151 deletion on mammary tumorigenesis by crossing Cd151-deficient mice with a spontaneously metastasising transgenic model of breast cancer induced by the polyoma middle T antigen (PyMT) driven by the murine mammary tumor virus promoter (MMTV). RESULTS: Cd151 deletion did not affect the normal development and differentiation of the mammary gland. While there was a trend towards delayed tumor onset in Cd151-/- PyMT mice compared to Cd151+/+ PyMT littermate controls, this result was only approaching significance (Log-rank test P-value =0.0536). Interestingly, Cd151 deletion resulted in significantly reduced numbers and size of primary tumors but did not appear to affect the number or size of metastases in the MMTV/PyMT mice. Intriguingly, no differences in the expression of markers of cell proliferation, apoptosis and blood vessel density was observed in the primary tumors. CONCLUSION: The findings from this study provide additional evidence that CD151 acts to enhance tumor formation initiated by a range of oncogenes and strongly support its relevance as a potential therapeutic target to delay breast cancer progression.