Senescence evasion by MCF-7 human breast tumor-initiating cells.
Senescence evasion by MCF-7 human breast tumor-initiating cells.
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DOI：
10.1186/bcr2583
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Weinfeld M
中科院分区：
文献类型：
--
作者：
Karimi-Busheri F;Rasouli-Nia A;Mackey JR;Weinfeld M
癌细胞的一个亚群，即肿瘤起始细胞，被认为是肿瘤发生以及对放疗和化疗耐药的驱动力。肿瘤起始细胞的持续存在可能取决于DNA损伤和检查点蛋白调节的改变，以及细胞凋亡或衰老倾向的降低。为了验证这一假设，我们从贴壁单层培养的MCF-7乳腺癌细胞中分离出CD24-/low/CD44+肿瘤起始细胞（作为乳腺球），并对乳腺球和单层MCF-7细胞暴露于电离辐射前后的细胞死亡和DNA损伤反应途径进行了全面比较。通过单细胞凝胶电泳测量单链和双链断裂修复。还通过组蛋白 H2AX 的磷酸化以及 53BP1 和 Rad51 病灶的形成来检查后者。通过膜联蛋白 V 结合的流式细胞术分析来量化细胞凋亡，并根据细胞 β-半乳糖苷酶活性来分析衰老。我们采用端粒重复扩增方案来量化端粒酶活性。通过蛋白质印迹分析检测和定量关键 DNA 修复和细胞周期调节蛋白的表达。我们的数据表明，与大量 MCF-7 细胞（主要是 CD24+/CD44+）相比，MCF-7 乳腺球细胞受益于与单层细胞相比的多方面细胞保护方法，包括活性氧水平降低、更活跃的 DNA 单链断裂修复 (SSBR) 途径，这可能是由于关键 SSBR 蛋白、人 AP 核酸内切酶 1 (Ape1) 的表达水平较高，由于端粒酶活性增加和 p21 蛋白表达水平低，衰老倾向显着降低。两种细胞类型之间的双链断裂修复 (DSBR) 率没有显着差异，但微球体中的 DSBR 似乎绕过了 H2AX 磷酸化的需要。 MCF-7 肿瘤起始细胞响应电离辐射而增强的存活率主要依赖于衰老途径的固有下调。由于 MCF-7 细胞是不易发生凋亡的癌细胞的代表，因此考虑衰老途径可能在靶向此类肿瘤的干细胞方面发挥作用。
A subpopulation of cancer cells, tumor-initiating cells, is believed to be the driving force behind tumorigenesis and resistance to radiation and chemotherapy. The persistence of tumor-initiating cells may depend on altered regulation of DNA damage and checkpoint proteins, as well as a reduced propensity to undergo apoptosis or senescence. To test this hypothesis, we isolated CD24-/low/CD44+ tumor-initiating cells (as mammospheres) from MCF-7 breast cancer cells grown in adherent monolayer culture, and carried out a comprehensive comparison of cell death and DNA damage response pathways prior to and after exposure to ionizing radiation in mammospheres and monolayer MCF-7 cells. Single and double-strand break repair was measured by single-cell gel electrophoresis. The latter was also examined by phosphorylation of histone H2AX and formation of 53BP1 and Rad51 foci. Apoptosis was quantified by flow-cytometric analysis of annexin V-binding and senescence was analyzed on the basis of cellular β-galactosidase activity. We employed the telomeric repeat amplification protocol to quantify telomerase activity. Expression of key DNA repair and cell cycle regulatory proteins was detected and quantified by western blot analysis. Our data demonstrate that in comparison to the bulk population of MCF-7 cells (predominantly CD24+/CD44+), the MCF-7 mammosphere cells benefit from a multifaceted approach to cellular protection relative to that seen in monolayer cells, including a reduced level of reactive oxygen species, a more active DNA single-strand break repair (SSBR) pathway, possibly due to a higher level of expression of the key SSBR protein, human AP endonuclease 1 (Ape1), and a significantly reduced propensity to undergo senescence as a result of increased telomerase activity and a low level of p21 protein expression. No significant difference was seen in the rates of double-strand break repair (DSBR) between the two cell types, but DSBR in mammospheres appears to by-pass the need for H2AX phosphorylation. Enhanced survival of MCF-7 tumor-initiating cells in response to ionizing radiation is primarily dependent on an inherent down-regulation of the senescence pathway. Since MCF-7 cells are representative of cancer cells that do not readily undergo apoptosis, consideration of senescence pathways may play a role in targeting stem cells from such tumors.
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影响因子：
4.8
作者：
Furuta, T;Takemura, H;Pommier, Y
通讯作者：
Pommier, Y
影响因子：
7.4
作者：
Fillmore, Christine M.;Kuperwasser, Charlotte
通讯作者：
Kuperwasser, Charlotte
影响因子：
11.2
作者：
Charafe-Jauffret E;Ginestier C;Iovino F;Wicinski J;Cervera N;Finetti P;Hur MH;Diebel ME;Monville F;Dutcher J;Brown M;Viens P;Xerri L;Bertucci F;Stassi G;Dontu G;Birnbaum D;Wicha MS
通讯作者：
Wicha MS
影响因子：
64.8
作者：
Falck, J;Mailand, N;Lukas, J
通讯作者：
Lukas, J
影响因子：
5.2
作者：
Bracker, Tomke U.;Giebel, Bernd;Thomale, Juergen
通讯作者：
Thomale, Juergen