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腾讯登录Nature:终于逮到你了！肿瘤干细胞
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<p align="left">癌症研究人员可以测定肿瘤细胞基因组的序列，扫描其异常的基因活性，剖析其突变的蛋白质和研究它们在实验室培养皿中的生长，但研究者一直无法跟踪细胞形成肿瘤的过程。现在三个独立研究小组在小鼠体内做到了这一点。他们的研究结果支持这样的观点：一小部分细胞驱动肿瘤的生长，而想要治愈癌症可能需要将这些所谓肿瘤干细胞清除。</p>
<p align="left"><!--more--></p>
目前还无法确认，这些从脑瘤，肠癌和皮肤癌研究的结论是否适用于其他类型肿瘤，但是得克萨斯大学西南医学中心的路易斯·帕拉达认为，如果它们适用于其他肿瘤，"将深刻地改变目前的化疗疗效评价和临床疗法的制定标准"。 不仅是看某种疗法是否缩小肿瘤，研究人员将更关注是否杀死了正确的细胞。
帕拉达和他的同事们想检测是否特异性标识健康成人神经干细胞的一个遗传标记，也可标识神经母细胞瘤中的癌症干细胞。他们发现，所有神经母细胞瘤样本中至少有几个标记细胞 - 大概是干细胞。未标记细胞可被标准化疗杀死，但肿瘤可迅速恢复。进一步的实验表明，未标记细胞起源于标记的细胞祖先。当研究者把化疗与抑制标记细胞的遗传手段相结合进行治疗时，帕拉达说，肿瘤显著缩小到"残留遗迹"的水平。
在另一项研究中，荷兰乌得勒支Hubrecht研究所的干细胞生物学家们把注意力瞄着了肠道。利用药物驱动的荧光素标志物表达系统，他们在小鼠体内证实，多种不同类型的肿瘤细胞，其实是来源于同一干细胞的。而且，这些干细胞是肿瘤发展的驱动力。
对皮肤癌的研究，Blanpain和他的小组标记单个肿瘤细胞，而不是特异地标记干细胞。他们发现，细胞表现出两种不同的分工模式：它们要么在慢慢耗尽前分裂出少数细胞，或者产生许多细胞。这再次证实，一类独特的细胞亚群是肿瘤生长的驱动力。
研究者说，下一步的研究计划将是，搞清楚这些实验所跟踪的细胞如何与通过多年移植实验所确定的，假定的癌症干细胞相联系的。研究人员已经紧锣密鼓地在寻找杀死这些细胞的方法;现在他们有更多的工具来测试这样的策略是否会奏效。
编译自：<a title="" href="http://www.nature.com/news/cancer-stem-cells-tracked-1.11087" target="_blank">Cancer stem cells tracked</a>
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<img src="http://www.bioon.com/biology/UploadFiles/201208/2012080216000311.jpg" alt="" width="113" height="149" border="0" hspace="0" />
<a title="" href="http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11344.html" target="_blank">doi:10.1038/nature11344 </a>
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<br/><strong>Defining the mode of tumour growth by clonal analysis</strong><br/>
Gregory Driessens,Benjamin Beck,Amélie Caauwe,Benjamin D. Simons& Cédric Blanpain
Recent studies using the isolation of a subpopulation of tumour cells followed by their transplantation into immunodeficient mice provide evidence that certain tumours1, 2, including squamous skin tumours3, 4, 5, contain cells with high clonogenic potential that have been referred to as cancer stem cells (CSCs). Until now, CSC properties have only been investigated by transplantation assays, and their existence in unperturbed tumour growth is unproven. Here we make use of clonal analysis of squamous skin tumours using genetic lineage tracing to unravel the mode of tumour growth in vivo in its native environment. To this end, we used a genetic labelling strategy that allows individual tumour cells to be marked and traced over time at different stages of tumour progression. Surprisingly, we found that the majority of labelled tumour cells in benign papilloma have only limited proliferative potential, whereas a fraction has the capacity to persist long term, giving rise to progeny that occupy a significant part of the tumour. As well as confirming the presence of two distinct proliferative cell compartments within the papilloma, mirroring the composition, hierarchy and fate behaviour of normal tissue, quantitative analysis of clonal fate data indicates that the more persistent population has stem-cell-like characteristics and cycles twice per day, whereas the second represents a slower cycling transient population that gives rise to terminally differentiated tumour cells. Such behaviour is shown to be consistent with double-labelling experiments and detailed clonal fate characteristics. By contrast, measurements of clone size and proliferative potential in invasive squamous cell carcinoma show a different pattern of behaviour, consistent with geometric expansion of a single CSC population with limited potential for terminal differentiation. This study presents the first experimental evidence for the existence of CSCs during unperturbed solid tumour growth.
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<img src="http://www.bioon.com/biology/UploadFiles/201208/2012080216000311.jpg" alt="" width="113" height="149" border="0" hspace="0" />
<a title="" href="http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11287.html" target="_blank">doi:10.1038/nature11287 </a>
PMC:
PMID:
</div>
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<br/><strong>A restricted cell population propagates glioblastoma growth after chemotherapy </strong><br/>
Jian Chen,1 Yanjiao Li,1 Tzong-Shiue Yu,1, 2, 4 Renée M. McKay,1 Dennis K. Burns,3 Steven G. Kernie1, 2, 4 & Luis F. Parada1
Glioblastoma multiforme is the most common primary malignant brain tumour, with a median survival of about one year1. This poor prognosis is due to therapeutic resistance and tumour recurrence after surgical removal. Precisely how recurrence occurs is unknown. Using a genetically engineered mouse model of glioma, here we identify a subset of endogenous tumour cells that are the source of new tumour cells after the drug temozolomide (TMZ) is administered to transiently arrest tumour growth. A nestin-ΔTK-IRES-GFP (Nes-ΔTK-GFP) transgene that labels quiescent subventricular zone adult neural stem cells also labels a subset of endogenous glioma tumour cells. On arrest of tumour cell proliferation with TMZ, pulse-chase experiments demonstrate a tumour re-growth cell hierarchy originating with the Nes-ΔTK-GFP transgene subpopulation. Ablation of the GFP+ cells with chronic ganciclovir administration significantly arrested tumour growth, and combined TMZ and ganciclovir treatment impeded tumour development. Thus, a relatively quiescent subset of endogenous glioma cells, with properties similar to those proposed for cancer stem cells, is responsible for sustaining long-term tumour growth through the production of transient populations of highly proliferative cells.
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<img src="http://www.bioon.com/biology/UploadFiles/201208/2012080312045344.gif" alt="" width="113" height="149" border="0" hspace="0" />
<a title="" href="http://www.sciencemag.org/content/early/2012/07/31/science.1224676" target="_blank">DOI: 10.1126/science.1224676 </a>
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<br/><strong>Lineage Tracing Reveals Lgr5+ Stem Cell Activity in Mouse Intestinal Adenomas </strong><br/>
Arnout G. Schepers*, Hugo J. Snippert*,?, Daniel E. Stange, Maaike van den Born, Johan H. van Es, Marc van de Wetering, Hans Clevers
The concept that tumors are maintained by dedicated stem cells, the so-called cancer stem cell hypothesis, has attracted great interest but remains controversial. Studying mouse models, we provide direct, functional evidence for the presence of stem cell activity within primary intestinal adenomas, a precursor to intestinal cancer. By “lineage retracing” using the multicolor Cre-reporter R26R-Confetti, we demonstrate that the crypt stem cell marker Lgr5 (leucine-rich repeat–containing heterotrimeric guanine nucleotide–binding protein–coupled receptor 5) also marks a subpopulation of adenoma cells that fuel the growth of established intestinal adenomas. These Lgr5+ cells, which represent about 5 to 10% of the cells in the adenomas, generate additional Lgr5+ cells as well as all other adenoma cell types. The Lgr5+ cells are intermingled with Paneth cells near the adenoma base, a pattern reminiscent of the architecture of the normal crypt niche.
<br/>来源：生物谷
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<p align="left">癌症研究人员可以测定肿瘤细胞基因组的序列，扫描其异常的基因活性，剖析其突变的蛋白质和研究它们在实验室培养皿中的生长，但研究者一直无法跟踪细胞形成肿瘤的过程。现在三个独立研究小组在小鼠体内做到了这一点。他们的研究结果支持这样的观点：一小部分细胞驱动肿瘤的生长，而想要治愈癌症可能需要将这些所谓肿瘤干细胞清除。</p>
<p align="left"><!--more--></p>
目前还无法确认，这些从脑瘤，肠癌和皮肤癌研究的结论是否适用于其他类型肿瘤，但是得克萨斯大学西南医学中心的路易斯·帕拉达认为，如果它们适用于其他肿瘤，"将深刻地改变目前的化疗疗效评价和临床疗法的制定标准"。 不仅是看某种疗法是否缩小肿瘤，研究人员将更关注是否杀死了正确的细胞。
帕拉达和他的同事们想检测是否特异性标识健康成人神经干细胞的一个遗传标记，也可标识神经母细胞瘤中的癌症干细胞。他们发现，所有神经母细胞瘤样本中至少有几个标记细胞 - 大概是干细胞。未标记细胞可被标准化疗杀死，但肿瘤可迅速恢复。进一步的实验表明，未标记细胞起源于标记的细胞祖先。当研究者把化疗与抑制标记细胞的遗传手段相结合进行治疗时，帕拉达说，肿瘤显著缩小到"残留遗迹"的水平。
在另一项研究中，荷兰乌得勒支Hubrecht研究所的干细胞生物学家们把注意力瞄着了肠道。利用药物驱动的荧光素标志物表达系统，他们在小鼠体内证实，多种不同类型的肿瘤细胞，其实是来源于同一干细胞的。而且，这些干细胞是肿瘤发展的驱动力。
对皮肤癌的研究，Blanpain和他的小组标记单个肿瘤细胞，而不是特异地标记干细胞。他们发现，细胞表现出两种不同的分工模式：它们要么在慢慢耗尽前分裂出少数细胞，或者产生许多细胞。这再次证实，一类独特的细胞亚群是肿瘤生长的驱动力。
研究者说，下一步的研究计划将是，搞清楚这些实验所跟踪的细胞如何与通过多年移植实验所确定的，假定的癌症干细胞相联系的。研究人员已经紧锣密鼓地在寻找杀死这些细胞的方法;现在他们有更多的工具来测试这样的策略是否会奏效。
编译自：<a title="" href="http://www.nature.com/news/cancer-stem-cells-tracked-1.11087" target="_blank">Cancer stem cells tracked</a>
<div id="ztload">
<div> </div>
<div>
<div>
<img src="http://www.bioon.com/biology/UploadFiles/201208/2012080216000311.jpg" alt="" width="113" height="149" border="0" hspace="0" />
<a title="" href="http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11344.html" target="_blank">doi:10.1038/nature11344 </a>
PMC:
PMID:
</div>
<div>
<br/><strong>Defining the mode of tumour growth by clonal analysis</strong><br/>
Gregory Driessens,Benjamin Beck,Amélie Caauwe,Benjamin D. Simons& Cédric Blanpain
Recent studies using the isolation of a subpopulation of tumour cells followed by their transplantation into immunodeficient mice provide evidence that certain tumours1, 2, including squamous skin tumours3, 4, 5, contain cells with high clonogenic potential that have been referred to as cancer stem cells (CSCs). Until now, CSC properties have only been investigated by transplantation assays, and their existence in unperturbed tumour growth is unproven. Here we make use of clonal analysis of squamous skin tumours using genetic lineage tracing to unravel the mode of tumour growth in vivo in its native environment. To this end, we used a genetic labelling strategy that allows individual tumour cells to be marked and traced over time at different stages of tumour progression. Surprisingly, we found that the majority of labelled tumour cells in benign papilloma have only limited proliferative potential, whereas a fraction has the capacity to persist long term, giving rise to progeny that occupy a significant part of the tumour. As well as confirming the presence of two distinct proliferative cell compartments within the papilloma, mirroring the composition, hierarchy and fate behaviour of normal tissue, quantitative analysis of clonal fate data indicates that the more persistent population has stem-cell-like characteristics and cycles twice per day, whereas the second represents a slower cycling transient population that gives rise to terminally differentiated tumour cells. Such behaviour is shown to be consistent with double-labelling experiments and detailed clonal fate characteristics. By contrast, measurements of clone size and proliferative potential in invasive squamous cell carcinoma show a different pattern of behaviour, consistent with geometric expansion of a single CSC population with limited potential for terminal differentiation. This study presents the first experimental evidence for the existence of CSCs during unperturbed solid tumour growth.
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<div> </div>
<div>
<div>
<img src="http://www.bioon.com/biology/UploadFiles/201208/2012080216000311.jpg" alt="" width="113" height="149" border="0" hspace="0" />
<a title="" href="http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11287.html" target="_blank">doi:10.1038/nature11287 </a>
PMC:
PMID:
</div>
<div>
<br/><strong>A restricted cell population propagates glioblastoma growth after chemotherapy </strong><br/>
Jian Chen,1 Yanjiao Li,1 Tzong-Shiue Yu,1, 2, 4 Renée M. McKay,1 Dennis K. Burns,3 Steven G. Kernie1, 2, 4 & Luis F. Parada1
Glioblastoma multiforme is the most common primary malignant brain tumour, with a median survival of about one year1. This poor prognosis is due to therapeutic resistance and tumour recurrence after surgical removal. Precisely how recurrence occurs is unknown. Using a genetically engineered mouse model of glioma, here we identify a subset of endogenous tumour cells that are the source of new tumour cells after the drug temozolomide (TMZ) is administered to transiently arrest tumour growth. A nestin-ΔTK-IRES-GFP (Nes-ΔTK-GFP) transgene that labels quiescent subventricular zone adult neural stem cells also labels a subset of endogenous glioma tumour cells. On arrest of tumour cell proliferation with TMZ, pulse-chase experiments demonstrate a tumour re-growth cell hierarchy originating with the Nes-ΔTK-GFP transgene subpopulation. Ablation of the GFP+ cells with chronic ganciclovir administration significantly arrested tumour growth, and combined TMZ and ganciclovir treatment impeded tumour development. Thus, a relatively quiescent subset of endogenous glioma cells, with properties similar to those proposed for cancer stem cells, is responsible for sustaining long-term tumour growth through the production of transient populations of highly proliferative cells.
</div>
</div>
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<div id="ztload">
<div> </div>
<div>
<div>
<img src="http://www.bioon.com/biology/UploadFiles/201208/2012080312045344.gif" alt="" width="113" height="149" border="0" hspace="0" />
<a title="" href="http://www.sciencemag.org/content/early/2012/07/31/science.1224676" target="_blank">DOI: 10.1126/science.1224676 </a>
PMC:
PMID:
</div>
<div>
<br/><strong>Lineage Tracing Reveals Lgr5+ Stem Cell Activity in Mouse Intestinal Adenomas </strong><br/>
Arnout G. Schepers*, Hugo J. Snippert*,?, Daniel E. Stange, Maaike van den Born, Johan H. van Es, Marc van de Wetering, Hans Clevers
The concept that tumors are maintained by dedicated stem cells, the so-called cancer stem cell hypothesis, has attracted great interest but remains controversial. Studying mouse models, we provide direct, functional evidence for the presence of stem cell activity within primary intestinal adenomas, a precursor to intestinal cancer. By “lineage retracing” using the multicolor Cre-reporter R26R-Confetti, we demonstrate that the crypt stem cell marker Lgr5 (leucine-rich repeat–containing heterotrimeric guanine nucleotide–binding protein–coupled receptor 5) also marks a subpopulation of adenoma cells that fuel the growth of established intestinal adenomas. These Lgr5+ cells, which represent about 5 to 10% of the cells in the adenomas, generate additional Lgr5+ cells as well as all other adenoma cell types. The Lgr5+ cells are intermingled with Paneth cells near the adenoma base, a pattern reminiscent of the architecture of the normal crypt niche.
<br/>来源：生物谷
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