Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Würzburg, Röntgenring 11, 97070 Würzburg, Germany.
Biochem Biophys Res Commun. 2010 Jun 11;396(4):793-9. doi: 10.1016/j.bbrc.2010.04.134. Epub 2010 May 4.
Due to their immune stimulating and apoptosis inducing properties, ligands of the TNF family attract increasing interest as therapeutic proteins. A general limitation of in vivo applications of recombinant soluble TNF ligands is their notoriously rapid clearance from circulation. To improve the serum half life of the TNF family members TNF, TWEAK and TRAIL, we genetically fused soluble variants of these molecules to human serum albumin (HSA). The serum albumin-TNF ligand fusion proteins were found to be of similar bioactivity as the corresponding HSA-less counterparts. Upon intravenous injection (i.v.), serum half life of HSA-TNF ligand fusion proteins, as determined by ELISA, was around 15 h as compared to approximately 1h for all of the recombinant control TNF ligands without HSA domain. Moreover, serum samples collected 6 or 24h after i.v. injection still contained high TNF ligand bioactivity, demonstrating that there is only limited degradation/inactivation of circulating HSA-TNF ligand fusion proteins in vivo. In a xenotransplantation model, significantly less of the HSA-TRAIL fusion protein compared to the respective control TRAIL protein was required to achieve inhibition of tumor growth indicating that the increased half life of HSA-TNF ligand fusion proteins translates into better therapeutic action in vivo. In conclusion, our data suggest that genetic fusion to serum albumin is a powerful and generally applicable mean to improve bioavailability and in vivo activity of TNF ligands.
由于 TNF 家族配体具有免疫刺激和诱导细胞凋亡的特性，因此作为治疗蛋白越来越受到关注。重组可溶性 TNF 配体在体内应用的一个普遍限制是它们在循环中迅速清除。为了提高 TNF 家族成员 TNF、TWEAK 和 TRAIL 的血清半衰期，我们将这些分子的可溶性变体基因融合到人血清白蛋白（HSA）上。研究发现，与相应的无 HSA 结构域的对照相比，血清白蛋白-TNF 配体融合蛋白具有相似的生物活性。通过静脉注射（i.v.），ELISA 测定的 HSA-TNF 配体融合蛋白的血清半衰期约为 15 小时，而所有无 HSA 结构域的重组对照 TNF 配体的半衰期约为 1 小时。此外，静脉注射后 6 或 24 小时采集的血清样本仍然含有高 TNF 配体生物活性，表明在体内循环的 HSA-TNF 配体融合蛋白只有有限的降解/失活。在异种移植模型中，与相应的对照 TRAIL 蛋白相比，HSA-TRAIL 融合蛋白需要更少的量就能抑制肿瘤生长，这表明 HSA-TNF 配体融合蛋白半衰期的延长转化为体内更好的治疗效果。总之，我们的数据表明，与血清白蛋白的基因融合是一种增强 TNF 配体生物利用度和体内活性的有效且普遍适用的方法。
