Proteolysis targeting chimeras (PROTACs) technology is a promising strategy for degrading proteins of interest. Traditional PROTACs, however, often face challenges such as poor solubility, low stability, and off-target toxicity. To address these challenges, we integrated nanotechnology to enhance the delivery of target-protein degraders to the tumor sites, thereby improving their properties. Here, we report silica-based nano-PROTACs (SiPROTACs) that feature multiple ligands on the surface to target and degrade the transmembrane protein epidermal growth factor receptor (EGFR). SiPROTACs, with a diameter of approximately 50 nm, can efficiently bind to EGFR, recruit cereblon (CRBN) to induce EGFR ubiquitination, and facilitate their degradation by proteasomes. In HCC-827 and PC-9 cell lines, SiPROTACs initiated EGFR degradation at a notably low concentration of 50 nM, demonstrating greater efficiency compared to traditional PROTACs. In HCC-827 xenograft tumor-bearing mice, SiPROTACs accumulated at tumor site for at least 48 h and exhibited significant anti-tumor effects in vivo without causing noticeable side effects. These findings suggest a novel approach for the application of PROTACs highlighting their therapeutic potential for the treatment of non-small cell lung cancer (NSCLC).
Yuxuan Wei,Zuxiao Chen,Chuyu Huang,Hong Cheng,Xiaofeng Jiang,Shiying Li
Spatiotemporal downregulation of immune checkpoint provides a promising strategy to activate anti-tumor immunity. In this work, a breast cancer targeted photodynamic degrader (designated as EIpro) is constructed to activate immunotherapy through EGFR degradation mediated PD-L1 downregulation. To be specific, we develop a chimeric peptide, comprising the photosensitizer Protoporphyrin IX (PpIX) and EGFR targeting peptide (QRHKPRE), to encapsulate an EGFR inhibitor afatinib (AFA) forming nanomicelle, namely EIpro. EIpro has a favorable stability and uniform nanosize distribution, preferring to accumulate in EGFR overexpressed breast cancer cells to amplify the chemotherapeutic effect and photodynamic elimination behavior. More interestingly, photodynamic therapy (PDT) produced reactive oxygen species (ROS) is able to damage breast cancer cells and induce immunogenic cell death (ICD) to release tumor associated antigens (TAAs), thereby degrading the nearby EGFR to downregulate PD-L1 and activate anti-tumor immunity. Beneficially, the multi-synergistic effects of EIpro show a robust therapeutic efficacy against primary and metastatic breast cancer with negligible systemic toxicity. This work provides a spatiotemporal strategy for protein degradation, which might inspire the development of sophisticated nanomedicine for effective tumor treatment.
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