RhoC Is an Unexpected Target of RhoGDI2 in Prevention of Lung Colonization of Bladder Cancer.
RhoC Is an Unexpected Target of RhoGDI2 in Prevention of Lung Colonization of Bladder Cancer.
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DOI：
10.1158/1541-7786.mcr-14-0420
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发表时间：
2015-03
期刊：
影响因子：
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通讯作者：
Theodorescu D
中科院分区：
文献类型：
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作者：
Griner EM;Dancik GM;Costello JC;Owens C;Guin S;Edwards MG;Brautigan DL;Theodorescu D
RhoGDI 2（ARHGDIB）抑制多种癌症的转移，但其机制尚不清楚;因此，阻碍了人类治疗方法的发展。RhoGDI 2是一种鸟嘌呤核苷酸解离抑制剂（GDI），用于Rho家族的GTP酶，被认为主要与Rac 1结合;然而，Rac 1的活化并不因RhoGDI 2在膀胱癌细胞中的表达而降低。为了更好地了解RhoGDI 2的GTdR结合伴侣，在膀胱癌细胞中采用基于质谱的蛋白质组学方法。正如预期的那样，内源性RhoGDI 2与Rac 1发生免疫共沉淀，出乎意料的是RhoC也是如此。进一步的分析表明，RhoGDI 2负调节RhoC，因为RhoGDI 2的敲低增加了响应于血清刺激的RhoC活化。相反，RhoGDI 2的过表达降低了RhoC的激活。RhoC促进膀胱癌细胞的生长和侵袭，因为敲低增加细胞倍增时间，减少通过Matrigel的侵袭，并减少软琼脂中的集落形成。重要的是，RhoC敲低减少了免疫受损小鼠中尾静脉注射后膀胱癌细胞的体内肺定植。最后，无偏转录组分析揭示了一组基因调控的RhoGDI 2过表达和RhoC敲低膀胱癌细胞。
RhoGDI2 (ARHGDIB) suppresses metastasis in a variety of cancers but the mechanism is unclear; thus, hampering development of human therapeutics. RhoGDI2 is a guanine nucleotide dissociation inhibitor (GDI) for the Rho family of GTPases thought to primarily bind to Rac1; however, Rac1 activation was not decreased by RhoGDI2 expression in bladder cancer cells. To better understand the GTPase binding partners for RhoGDI2, a mass spectrometry-based proteomic approach was employed in bladder cancer cells. As expected endogenous RhoGDI2 co-immunoprecipitates with Rac1 and unexpectedly so does RhoC. Further analysis demonstrated that RhoGDI2 negatively regulates RhoC, as knockdown of RhoGDI2 increased RhoC activation in response to serum stimulation. Conversely, overexpression of RhoGDI2 decreased RhoC activation. RhoC promoted bladder cancer cell growth and invasion, as knockdown increased cell doubling time, decreased invasion through Matrigel, and decreased colony formation in soft agar. Importantly, RhoC knockdown reduced in vivo lung colonization by bladder cancer cells following tail vein injection in immune compromised mice. Finally, unbiased transcriptome analysis revealed a set of genes regulated by RhoGDI2 over-expression and RhoC knockdown in bladder cancer cells.