Promotion of variant human mammary epithelial cell outgrowth by ionizing radiation: an agent-based model supported by in vitro studies.
Promotion of variant human mammary epithelial cell outgrowth by ionizing radiation: an agent-based model supported by in vitro studies.
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DOI：
10.1186/bcr2477
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Yaswen P
中科院分区：
文献类型：
--
作者：
Mukhopadhyay R;Costes SV;Bazarov AV;Hines WC;Barcellos-Hoff MH;Yaswen P
大多数人乳腺上皮细胞（HMEC）从组织学正常的乳腺组织培养进入衰老状态，称为停滞后5至20人口doubling。这些衰老细胞显示体积增大，含有衰老相关的β-半乳糖苷酶活性，并表达细胞周期蛋白依赖性激酶抑制剂p16 INK 4A（CDKN 2A; p16）。然而，在无血清培养基中生长的HMEC自发地以低频率产生能够长期生长并且对基因组不稳定性敏感的变体（v）HMEC。我们研究了电离辐射是否会增加女性乳腺癌的风险，影响vHMEC的生长速度。将预停滞HMEC培养物暴露于5至200 cGy的稀疏（X射线或γ射线）或密集（1 GeV/amu 56 Fe）电离辐射。在辐射暴露后4 - 6周，当vHMEC斑块变得明显时，在传代培养的辐射或未辐射群体中测定增殖（溴脱氧尿苷掺入）、衰老（衰老相关β-半乳糖苷酶活性）和p16表达。还监测了后续传代中的长期生长潜力和p16启动子甲基化。基于代理的建模包含一组简单的规则和基本假设，用于模拟vHMEC的生长并评估机械假设。与来自未辐照细胞的培养物相比，来自辐照细胞的培养物含有显著更多的缺乏衰老相关β-半乳糖苷酶或p16表达的vHMEC。正如预期的那样，来自未辐照和辐照细胞的停滞后vHMEC培养物比停滞前HMEC培养物表现出更广泛的p16基因甲基化。然而，vHMEC样本中单个CpG位点的甲基化程度与传代次数或处理无关。暴露于稀疏或密集的电离辐射引起类似的增加vHMEC的数量相比，未经辐照的控制。基于代理的建模表明，辐射诱导的正常HMEC的过早衰老最有可能通过缓解空间限制加速vHMEC的生长。随后使用vHMEC和衰老细胞的确定共培养物的实验支持该机制。我们的研究表明，电离辐射可以促进具有癌前潜能的表观遗传改变细胞的生长。
Most human mammary epithelial cells (HMEC) cultured from histologically normal breast tissues enter a senescent state termed stasis after 5 to 20 population doublings. These senescent cells display increased size, contain senescence associated β-galactosidase activity, and express cyclin-dependent kinase inhibitor, p16INK4A (CDKN2A; p16). However, HMEC grown in a serum-free medium, spontaneously yield, at low frequency, variant (v) HMEC that are capable of long-term growth and are susceptible to genomic instability. We investigated whether ionizing radiation, which increases breast cancer risk in women, affects the rate of vHMEC outgrowth. Pre-stasis HMEC cultures were exposed to 5 to 200 cGy of sparsely (X- or γ-rays) or densely (1 GeV/amu 56Fe) ionizing radiation. Proliferation (bromodeoxyuridine incorporation), senescence (senescence-associated β-galactosidase activity), and p16 expression were assayed in subcultured irradiated or unirradiated populations four to six weeks following radiation exposure, when patches of vHMEC became apparent. Long-term growth potential and p16 promoter methylation in subsequent passages were also monitored. Agent-based modeling, incorporating a simple set of rules and underlying assumptions, was used to simulate vHMEC outgrowth and evaluate mechanistic hypotheses. Cultures derived from irradiated cells contained significantly more vHMEC, lacking senescence associated β-galactosidase or p16 expression, than cultures derived from unirradiated cells. As expected, post-stasis vHMEC cultures derived from both unirradiated and irradiated cells exhibited more extensive methylation of the p16 gene than pre-stasis HMEC cultures. However, the extent of methylation of individual CpG sites in vHMEC samples did not correlate with passage number or treatment. Exposure to sparsely or densely ionizing radiation elicited similar increases in the numbers of vHMEC compared to unirradiated controls. Agent-based modeling indicated that radiation-induced premature senescence of normal HMEC most likely accelerated vHMEC outgrowth through alleviation of spatial constraints. Subsequent experiments using defined co-cultures of vHMEC and senescent cells supported this mechanism. Our studies indicate that ionizing radiation can promote the outgrowth of epigenetically altered cells with pre-malignant potential.
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DOI：
10.1073/pnas.93.18.9821
发表时间：
1996-09-03
影响因子：
11.1
作者：
Herman, JG;Graff, JR;Baylin, SB
通讯作者：
Baylin, SB
DOI：
10.1073/pnas.92.20.9363
发表时间：
1995-09-26
影响因子：
11.1
作者：
DIMRI, GP;LEE, XH;CAMPISI, J
通讯作者：
CAMPISI, J
DOI：
10.1016/j.mrfmmm.2005.09.008
发表时间：
2006-05-11
影响因子：
2.3
作者：
Barcellos-Hoff, Mary Helen;Costes, Sylvain V.
通讯作者：
Costes, Sylvain V.
影响因子：
4.3
作者：
Markus, M;Böhm, D;Schmick, M
通讯作者：
Schmick, M
影响因子：
1.6
作者：
Kansal, AR;Torquato, S;Deisboeck, TS
通讯作者：
Deisboeck, TS