Overexpressed FKBP5 mediates colorectal cancer progression and sensitivity to FK506 treatment via the NF-κB signaling pathway

Colorectal cancer (CRC) is a common and deadly tumor. FK506-binding protein 5 (FKBP5) is associated with some cancers, but the role of FKBP5 in CRC is not clear. The present study aimed to reveal the relationship between FKBP5 and CRC and to uncover the roles of FK506 in CRC. In total, 96 CRC patients were recruited. Survival analysis was conducted using the Kaplan-Meier method and COX regression analyses. Bioinformatics analyses were performed to explore the functions of FKBP5. The mechanisms of FKBP5 and the roles of FK506 in CRC progression were clarified by immunohistochemistry, MTS, scratch assay, transwell and flow cytometric analyses via in vitro and in vivo experiments. FKBP5 was overexpressed in 77 cancer tissues compared to that in matched normal tissues, and the overall survival rate of these patients was relatively shorter. Bioinformatics analyses showed that FKBP5 regulates proliferation, invasion, migration, epithelial-mesenchymal transition and nuclear factor-kappa B (NF-κB) signaling. The upregulation or downregulation of FKBP5 dramatically increases or decreases the proliferation, invasion and migration abilities of CRC cells. The expression of NF-κB, inhibitor B kinase α, matrix metalloproteinase-2 and metalloproteinase-9 positively correlated with FKBP5. FK506 inhibits the progression of CRC via the FKBP5/NF-κB signaling pathway. Our study identified a regulatory role for FKBP5 in CRC progression. Therefore, targeting FKBP5 may provide a novel treatment approach for CRC. FK506 can inhibit the progression of CRC by restraining the FKBP5/NF-κB signaling pathway and is expected to become a new drug for the treatment of CRC.

Improved Antiglioblastoma Activity and BBB Permeability by Conjugation of Paclitaxel to a Cell-Penetrative MMP-2-Cleavable Peptide

In order to solve the problems of receptor promiscuity and poor blood-brain barrier (BBB) penetration in the treatment of glioblastomas (GBM), a novel dual-functional nanocomplex drug delivery system is developed based on the strategy of peptide-drug conjugates. In this study, SynB3-PVGLIG-PTX is designed and screened out by matrix metalloproteinase-2 (MMP-2), to which it exhibits the best affinity. The MMP-2-sensitive peptide (PVGLIG) and a cell-penetration peptide (SynB3) are combined to form a dual-functional peptide. Moreover, as a drug-peptide nanocomplex, SynB3-PVGLIG-PTX exhibited a high potential to form an aggregation with good solubility that can release paclitaxel (PTX) through the cleavage of MMP-2. From a functional perspective, it is found that SynB3-PVGLIG-PTX can specifically inhibit the proliferation, migration, and invasion of GBM cells in vitro in the presence of MMP-2, in contrast to that observed in MMP-2 siRNA transfected cells. Further investigation in vivo shows that SynB3-PVGLIG-PTX easily enters the brain of U87MG xenograft nude mice and can generate a better suppressive effect on GBM through a controlled release of PTX from SynB3-PVGLIG-PTX compared with PTX and temozolomide. Thus, it is proposed that SynB3-PVGLIG-PTX can be used as a novel drug-loading delivery system to treat GBM due to its specificity and BBB permeability.