Therapeutic Effect of IL-4 Receptor-Targeting Pro-Apoptotic Peptide (AP1-ELP-KLAK) in Glioblastoma Tumor Model

Background: Thermal-responsive self-assembled elastin-like polypeptide (ELP)-based nanoparticles are an emerging platform for controlled delivery of therapeutic peptides, proteins and small molecular drugs. The antitumor effect of bioengineered chimeric poly peptide AP1-ELP-KLAK containing an interleukin-4 receptor (IL-4R) targeting peptide and pro-apoptotic peptide (KLAKLAK) was evaluated in glioblastoma (GBM) in vitro and in vivo. Methods and Results: Herein, the therapeutic effect of AP1-ELP-KLAK was tested in advanced, and less curable glioblastoma cells with higher expression of IL-4R. Glioblastoma cell lines stably expressing different reporter systems i.e., caspase-3 sensor (surrogate marker for cellular apoptosis) or effluc/enhanced firefly luciferase (cellular viability) were established to measure cell death non-invasively. Bioluminescence imaging (BLI) of D54/effluc and U97MG/effluc treated with AP1-ELP-KLAK exhibited higher cell death up to 2-3-fold than the control. Treatment with AP1-ELP-KLAK resulted in time-dependent increase of caspase-3 sensor BLI activity in D54/C cells and D54/C tumor-bearing mice. Intravenous injection of AP1-ELP-KLAK dramatically reduced tumor growth by inducing cellular apoptosis in D54/effluc tumor-bearing mice. Further, the immuno-histological examination of the excised tumor tissue confirmed the presence of apoptotic cells as well as caspase-3 activation. Conclusion: Collectively, AP1-ELP-KLAK effectively induced cellular apoptosis of glioblastoma cells and non-invasive imaging provides a window for real-time monitoring of antitumor effect with the provision of improving therapeutic efficacy in a glioblastoma mice model.

Automated summary

The study demonstrated that AP1-ELP-KLAK effectively induced cellular apoptosis in glioblastoma cells with high expression of IL-4R. Real-time monitoring of therapeutic effect using BLI technology showed that AP1-ELP-KLAK reduced tumor growth and induced cellular apoptosis.