Stanley Manne Children's Research Institute, Cancer Biology and Epigenomics Program, Northwestern University Feinberg School of Medicine, Robert H. Lurie Comprehensive Cancer Center, Chicago, Illinois.
SerPlus Technology LLC, Belmont, California.
Mol Cancer Res. 2014 Oct;12(10):1480-91. doi: 10.1158/1541-7786.MCR-14-0067. Epub 2014 Sep 25.
Patients with metastatic disease face high rates of mortality with a paucity of therapeutic options. Protein-based therapeutics provide advantages over traditional chemotherapy through increased specificity, decreased immune impairment, and more direct means of delivery. However, development is often hindered because of insufficient knowledge about protein processing by cells when exogenously applied. This study focuses on recombinant Maspin (rMaspin), a serine protease inhibitor (SERPINB5), which alters invasive properties when directly applied to cancer cells. Previous evidence suggests differences in the effects of rMaspin treatment when compared with endogenous reexpression, with little explanation for these discrepancies. A leading hypothesis is that exogenously applied rMaspin is subject to different regulatory and/or processing mechanisms in cancer cells when compared with endogenous expression. Therefore, a more detailed understanding of the mechanisms of internalization and subcellular trafficking of rMaspin is needed to guide future translational development. We describe the molecular trafficking of rMaspin in cytoplasmic vesicles of the endosomal/lysosomal pathway and characterize its uptake by multiple endocytic mechanisms. Time-lapse laser scanning confocal microscopy shows the uptake, in real time, of dye-labeled rMaspin in cancer cells. This study indicates that cellular processing of rMaspin plays a key role by affecting its biologic activity and highlights the need for new approaches aimed at increasing the availability of rMaspin when used to treat cancer.
Novel characterization of internalization and subcellular trafficking of rMaspin provides new insights for future therapeutic development.
转移性疾病患者死亡率高，治疗选择有限。蛋白质治疗药物通过提高特异性、降低免疫损伤和更直接的给药方式提供了优于传统化疗的优势。然而，由于对外源性应用时细胞对蛋白质的加工了解不足，开发常常受到阻碍。本研究关注重组 Maspin(rMaspin)，一种丝氨酸蛋白酶抑制剂(SERPINB5)，当直接应用于癌细胞时会改变其侵袭特性。先前的证据表明，与内源性重新表达相比，rMaspin 治疗的效果存在差异，但对这些差异的解释很少。一个主要假设是，与内源性表达相比，外源性应用的 rMaspin 在癌细胞中受到不同的调节和/或加工机制的影响。因此，需要更详细地了解 rMaspin 的内化和细胞内转运机制，以指导未来的转化发展。我们描述了 rMaspin 在胞质小泡的内体/溶酶体途径中的分子转运，并对其通过多种内吞作用机制的摄取进行了表征。实时激光扫描共聚焦显微镜显示了染料标记的 rMaspin 在癌细胞中的实时摄取。这项研究表明，rMaspin 的细胞内加工通过影响其生物学活性起着关键作用，并强调需要新的方法来增加 rMaspin 的可用性，以用于治疗癌症。
对 rMaspin 的内化和细胞内转运的新特征为未来的治疗发展提供了新的见解。
