Inhibition of tumor cell growth by RTP/rit42 and its responsiveness to p53 and DNA damage.
Inhibition of tumor cell growth by RTP/rit42 and its responsiveness to p53 and DNA damage.
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发表时间：
1998-10
期刊：
影响因子：
11.2
通讯作者：
S. Kurdistani;P. Arizti;C. Reimer;M. Sugrue;S. Aaronson;S. W. Lee
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文献类型：
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作者：
S. Kurdistani;P. Arizti;C. Reimer;M. Sugrue;S. Aaronson;S. W. Lee
通过差异筛选技术，我们鉴定了一个在正常细胞和肿瘤细胞中具有差异表达的cDNA克隆。这个克隆，命名为rit 42（减少肿瘤，42 kDa），以前分离的同型半胱氨酸诱导基因在人类内皮细胞（RTP），和相同的或高度相关的雄激素反应基因在小鼠中也已确定。北方印迹分析和原位杂交表明，与正常细胞相比，在肿瘤细胞，包括来自乳腺和前列腺的细胞中的表达显著减少。RTP/rit 42 mRNA随细胞分裂周期而变化，在G1期和G2-M期表达最高，S期表达较低。RTP/rit 42 mRNA在肿瘤细胞中无双相表达。将rit 42 cDNA导入人癌细胞中在体外和裸鼠中均降低细胞生长。此外，在null-p53细胞系中的四环素调节的p53诱导系统的分析表明，RTP/rit 42 mRNA的表达增加伴随着p53的表达，并遵循类似的时间过程。此外，DNA损伤剂诱导RTP/rit 42表达的p53依赖的方式，但独立于p53介导的G1期阻滞。FLAG表位标记的RTP/rit 42蛋白的免疫荧光分析显示，DNA损伤后，细胞质定位模式与重新分配到细胞核。我们已经将RTP/rit 42定位于人类染色体8q24.3。总之，这些结果与RTP/rit 42的生长抑制作用一致，并且其下调可能有助于肿瘤恶性表型。
Through a differential screening technique, we have identified a cDNA clone with differential expression in normal versus tumor cells. This clone, designated rit42 (reduced in tumor, 42 kDa), was previously isolated as a homocysteine-inducible gene in human endothelial cells (RTP), and the same or a highly related androgen-responsive gene in mouse has also been identified. Both Northern blot analysis and in situ hybridization demonstrated a significantly diminished expression in tumor cells, including those derived from breast and prostate when compared with normal cells. It was shown that RTP/rit42 mRNA cycles with cell division, peaking at G1 and G2-M, with lower expression in S phase. The biphasic expression of RTP/rit42 mRNA was absent in tumor cells. Introduction of rit42 cDNA into human cancer cells reduced cell growth both in vitro and in nude mice. Moreover, analysis of a tetracycline-regulated p53-inducible system in null-p53 cell lines showed that RTP/rit42 mRNA expression increased concomitantly with p53 expression and followed a similar time course. In addition, DNA-damaging agents induced RTP/rit42 expression in a p53-dependent manner but independent of a p53-mediated G1 arrest. Immunofluorescence analysis of a FLAG epitope-tagged RTP/rit42 protein revealed a cytoplasmic localization pattern with redistribution to the nucleus upon DNA damage. We have localized RTP/rit42 to human chromosome 8q24.3. Taken together, these results are consistent with a growth inhibitory role for RTP/rit42, and its down-regulation may contribute to the tumor malignant phenotype.