Florey Neuroscience Institutes, University of Melbourne, Melbourne, VIC, 3010, Australia.
Amino Acids. 2010 Jul;39(2):409-16. doi: 10.1007/s00726-009-0454-1. Epub 2009 Dec 31.
Relaxin is a pleiotropic hormone which exerts its biological functions through its G-protein coupled receptor, RXFP1. While relaxin is well known for its reproductive and antifibrotic roles, recent studies suggest that it is produced by cancer cells and acts on RXFP1 to induce growth and metastasis. Furthermore, more recently Silvertown et al. demonstrated that lentiviral production of a human gene-2 (H2) relaxin analog reduced the growth of prostate xenograft tumors. The authors proposed that the lentivirally produced peptide was an RXFP1 antagonist; however, the processed form of the peptide produced was not demonstrated. In this study, we have chemically synthesized the H2 relaxin analog, B-R13/17K H2 relaxin, and subjected it to detailed chemical characterization by HPLC, MALDI-TOF mass spectrometry, and amino acid analysis. The biological activity of the synthetic peptide was then tested in three different cell lines. It was found to bind with 500-fold lower affinity than H2 relaxin to RXFP1 receptors over-expressed in HEK-293T cells where it acted as a partial agonist. However, in cells which natively express the RXFP1 receptor, rat renal myofibroblasts and MCF-7 cancer cells, it acted as a full antagonist. Importantly, it was able to significantly inhibit cell invasion induced by H2 relaxin in MCF-7 cells consistent with the results of the lentiviral-driven expression in prostate cancer cells. The relaxin analog, B-R13/17K H2, can now be used as a tool to further understand RXFP1 function, and serve as a template for drug design for a therapeutic to treat prostate and other cancers.
松弛素是一种多功能激素，通过其 G 蛋白偶联受体 RXFP1 发挥其生物学功能。虽然松弛素以其生殖和抗纤维化作用而闻名，但最近的研究表明，它是由癌细胞产生的，并作用于 RXFP1 诱导生长和转移。此外，最近 Silvertown 等人证明，慢病毒产生的人基因-2（H2）松弛素类似物减少了前列腺异种移植肿瘤的生长。作者提出，慢病毒产生的肽是 RXFP1 拮抗剂；然而，未证明产生的肽的加工形式。在这项研究中，我们通过 HPLC、MALDI-TOF 质谱和氨基酸分析对 H2 松弛素类似物 B-R13/17K H2 松弛素进行了化学合成，并对其进行了详细的化学表征。然后在三种不同的细胞系中测试了合成肽的生物学活性。结果发现，与在过表达 RXFP1 受体的 HEK-293T 细胞中，H2 松弛素相比，该肽对 RXFP1 受体的结合亲和力低 500 倍，并且作为部分激动剂起作用。然而，在天然表达 RXFP1 受体的细胞中，大鼠肾成纤维细胞和 MCF-7 癌细胞中，它作为完全拮抗剂起作用。重要的是，它能够显著抑制 H2 松弛素诱导的 MCF-7 细胞侵袭，这与前列腺癌细胞中慢病毒驱动表达的结果一致。松弛素类似物 B-R13/17K H2 现在可以用作进一步了解 RXFP1 功能的工具，并作为治疗前列腺癌和其他癌症的药物设计的模板。
