Expression of the hMSH6 mismatch-repair protein in colon cancer and HeLa cells.
Expression of the hMSH6 mismatch-repair protein in colon cancer and HeLa cells.
复制标题
hMSH6 错配修复蛋白在结肠癌和 HeLa 细胞中的表达。
DOI：
10.4414/smw.2002.09855
复制
发表时间：
2002
影响因子：
2.9
通讯作者：
Giancarlo Marra
中科院分区：
文献类型：
--
作者：
Helen Klingler;Christine Hemmerle;Fridolin Bannwart;Ritva Haider;M. Cattaruzza;Giancarlo Marra
原则
10%至15%的人类结肠癌与DNA错配修复（MMR）系统的遗传性或体细胞缺陷有关，该系统已进化为纠正生物合成错误，例如S期DNA复制过程中出现的核苷酸错误掺入或失调。细胞周期。虽然MMR基因的表达预期是细胞周期依赖性的，但我们和其他人观察到MMR蛋白hMSH 2和hMLH 1在增殖细胞中组成型表达。
方法
在这项研究中，我们将我们的观察扩展到另一种必需的MMR蛋白，hMSH 6。我们使用免疫组化来评估这种蛋白在人类结直肠粘膜和肿瘤中的表达模式，以及在同步化的HeLa-S3细胞中，我们分析了其在细胞周期中的稳态水平。
结果
我们发现，hMSH 6在正常结直肠隐窝和结肠癌中的表达的免疫组化模式显着不同，从其他MMR蛋白，与hMSH 6阳性的复制细胞的百分比低得多。这意味着hMSH 6可能是细胞周期调控的。为了在模型系统中验证这一假设，我们将HeLa-S3细胞与有丝分裂摇脱同步，发现在整个细胞周期中均可检测到hMSH 6蛋白，但当细胞从G1期进展到S期时，其稳态水平增加。
讨论
当细胞进入S期时，hMSH 6稳态水平的增加是预期的，因为MMR在DNA复制期间起作用。然而，在该细胞模型中，在细胞周期期间hMSH 6的总体低水平振荡显然不符合免疫组织化学表型。我们认为这种差异是由于人类细胞系在体内的增殖速率比正常和肿瘤性结直肠细胞高得多。
PRINCIPLES
10 to 15% of human colon cancers are associated with an inherited or somatic defect of the DNA Mismatch Repair (MMR) system, which has evolved to correct biosynthetic errors such as nucleotide mis-incorporations or misalignments arising during DNA replication in the S phase of the cell-cycle. Although expression of the MMR genes was expected to be cell-cycle dependent, we and others observed that the MMR proteins hMSH2 and hMLH1 are expressed constitutively in proliferating cells.
METHODS
In this study we extend our observations to another essential MMR protein, hMSH6. We used immunohistochemistry to evaluate the expression pattern of this protein in human colorectal mucosa and tumours, as well as in synchronised HeLa-S3 cells, in which we analysed its steady-state levels during the cell-cycle.
RESULTS
We show that the immunohistochemical pattern of expression of hMSH6 in normal colorectal crypts and in colon cancers differs significantly from that of the other MMR proteins, with a much lower percentage of replicating cells being hMSH6-positive. This implies that hMSH6 could be cell-cycle regulated. In order to test this hypothesis in a model system, we synchronised HeLa-S3 cells with mitotic shake-off and found that the hMSH6 protein was detectable throughout the cell-cycle, but that its steady-state level increased when cells progressed from G1 to S-phase.
DISCUSSION
The increase of hMSH6 steadystate level when cells enter S-phase was expected, since MMR acts during DNA replication. However, the overall low level of oscillations of hMSH6 during the cell-cycle in this cellular model apparently does not fit the immunohistochemical phenotype. We believe that this discrepancy is due to the fact that human cell lines proliferate at a much higher rate than normal and neoplastic colorectal cells in vivo.
影响因子：
11.2
作者：
M. Meyers;Maria Theodosiou;Samir Acharya;E. Odegaard;Teresa Wilson;Janet E. Lewis;Thomas W. Davis;Carmell Wilson Van Patten;Richard Fishel;D. Boothman
通讯作者：
M. Meyers;Maria Theodosiou;Samir Acharya;E. Odegaard;Teresa Wilson;Janet E. Lewis;Thomas W. Davis;Carmell Wilson Van Patten;Richard Fishel;D. Boothman
影响因子：
11.2
作者：
R. Kolodner;J. Tytell;J. Schmeits;M. Kane;R. Gupta;J. Weger;S. Wahlberg;E. Fox;David Peel;A. Ziogas;J. Garber;S. Syngal;H. Anton-Culver;Frederick P. Li
通讯作者：
R. Kolodner;J. Tytell;J. Schmeits;M. Kane;R. Gupta;J. Weger;S. Wahlberg;E. Fox;David Peel;A. Ziogas;J. Garber;S. Syngal;H. Anton-Culver;Frederick P. Li
影响因子：
9.8
作者：
Cunningham, JM;Kim, CY;Thibodeau, SN
通讯作者：
Thibodeau, SN