Inhibition of FAK signaling activated by urokinase receptor induces dormancy in human carcinoma cells in vivo
Inhibition of FAK signaling activated by urokinase receptor induces dormancy in human carcinoma cells in vivo
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DOI：
10.1038/sj/onc/1205342
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发表时间：
2002-04-11
期刊：
影响因子：
8
通讯作者：
Ghiso, JAA
中科院分区：
文献类型：
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作者：
Ghiso, JAA
在几种人类癌症中过表达的粘着斑激酶（FAK）的激活诱导培养中细胞的存活、增殖和运动，但其在体内人类肿瘤生长中的功能重要性尚未阐明。我探讨了FAK在调节人癌细胞HEp 3致瘤性中的作用。这些细胞过表达尿激酶受体（uPAR），其通过激活x5 β 1整联蛋白，通过FAK和Src启动细胞内信号，导致ERK激活和体内致瘤性。在这些细胞中下调uPAR导致FAK磷酸化水平降低3 -5倍，并与Src和体内休眠相关。通过uPAR的再表达，FAK磷酸化和体内生长能力都得到恢复。通过FAK磷酸化、GTP负载的Ras和ERK活化测量的T-HEp 3细胞中的FAK信号传导途径被已知具有显性负功能的FAK相关非激酶（FRNK）的瞬时或稳定转染抑制，但不被FRNK突变形式（S1034-FRNK）抑制。最重要的是，虽然接种到鸡胚CAM上的载体-和突变体-S1034-FRNK转染的细胞形成了逐渐生长的肿瘤，但表达HA-FRNK的T-HEp 3细胞在体内不增殖并保持休眠至少6周。两种细胞类型在体内具有相似的凋亡率，并且p38（SAPK）或PI 3 K-Akt信号通路不受FRNK的影响。FRNK诱导的休眠可以通过表达活性R4 F-Mek 1突变体来恢复。这些结果表明，活性FAK是uPAR调节的HEp 3细胞致瘤性的重要介质，并且通过下调uPAR或通过表达FRNK来中断FAK促有丝分裂信号传导可以迫使人癌细胞进入休眠。
Activation of focal adhesion kinase (FAK), overexpressed in several human cancers, induces survival, proliferation and motility of cells in culture, but its functional importance in human tumor growth in vivo has not been elucidated. I explored the role of FAK in regulating tumorigenicity of human carcinoma cells, HEp3. These cells overexpress urokinase receptor (uPAR) which, by activating x5beta1 integrin, initiates an intracellular signal through FAK and Src leading to ERK activation and tumorigenicity in vivo. Down regulation of uPAR in these cells led to a similar to3-5-fold reduction in FAK phosphorylation and association with Src and dormancy in vivo. Both FAK phosphorylation and ability to grow in vivo were restored by re-expression of uPAR. The FAK signaling pathway in T-HEp3 cells, measured by FAK phosphorylation, GTP-loaded Ras and ERK activation, was inhibited by transient or stable transfection of FAK related non-kinase (FRNK), known to have a dominant negative function, but not by a FRNK mutant version (S1034-FRNK). Most importantly, while vector- and mutant-S1034-FRNK transfected cells inoculated onto chicken embryo CAMs formed progressively growing tumors, the HA-FRNK-expressing T-HEp3 cells did not proliferate in vivo and remained dormant for at least 6 weeks. Both cell types had similar rate of apoptosis in vivo and the p38(SAPK) or PI3K-Akt signaling pathways were unaffected by FRNK. FRNK induced dormancy could be reverted by expression of an active-R4F-Mek1 mutant. These results show that active FAK is an important mediator of uPAR-regulated tumorigenicity of HEp3 cells and that interruption of FAK mitogenic signaling either through down-regulation of uPAR or by expression of FRNK can force human carcinoma cells into dormancy.