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  2. PER2 binding to HSP90 enhances immune response against oral squamous cell carcinoma by inhibiting IKK/NF-κB pathway and PD-L1 expression

PER2 binding to HSP90 enhances immune response against oral squamous cell carcinoma by inhibiting IKK/NF-κB pathway and PD-L1 expression

  • J Immunother Cancer. 2023 Nov;11(11):e007627. doi: 10.1136/jitc-2023-007627.
Zhiwei Zhang 1 Deping Sun 2 Hong Tang 1 Jie Ren 3 Shilin Yin 1 Kai Yang 4
Affiliations

Affiliations

  • 1 Department of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
  • 2 Department of Otolaryngology Head and Neck Surgery, University-Town Hospital of Chongqing Medical University, Chongqing, China.
  • 3 Department of Stomatology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
  • 4 Department of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China cqfyyk@hotmail.com.
Abstract

Background: Programmed death-ligand 1 (PD-L1) contributes to the immune escape of tumor cells and is a critical target for antitumor immunotherapy. However, the molecular mechanisms regulating PD-L1 expression remain unclear, hindering the development of effective therapies. Here we investigate the role and molecular mechanism of the core clock gene Period2 (PER2) in regulating PD-L1 expression and its role in the combination therapy of oral squamous cell carcinoma (OSCC).

Methods: Quantitative Real-Time PCR, western blotting or immunohistochemistry to detect expression of PER2 and PD-L1 in OSCC tissues and cells. Overexpression and knockdown of PER2 detects the function of PER2. Bioinformatics, immunoprecipitation, GST pull-down, CHX chase assay and western blot and strip to detect the mechanism of PER2 regulation for PD-L1. A humanized immune reconstitution subcutaneous xenograft mouse model was established to investigate the combination therapy efficacy.

Results: In OSCC tissues and cells, PER2 expression was reduced and PD-L1 expression was increased, the expression of PER2 was significantly negatively correlated with PD-L1. In vitro and in vivo experiments demonstrated that PER2 inhibited PD-L1 expression and enhanced T-cell-mediated OSCC cell killing by suppressing the IKK/NF-κB pathway. Mechanistically, PER2 binds to heat shock protein 90 (HSP90) through the PAS1 domain and reduces the interaction of HSP90 with inhibitors of kappa B kinase (IKKs), promoting the ubiquitination of IKKα/β and p65 nuclear translocation to inhibit IKK/NF-κB pathway, thereby suppressing PD-L1 expression. In humanized immune reconstitution subcutaneous xenograft mouse model, it was demonstrated that PER2 targeting combined with anti-PD-L1 treatment improved the inhibition of OSCC growth by promoting CD8+ T-cell infiltration into the tumor.

Conclusions: Our findings reveal the role and mechanism of PD-L1 regulation by PER2 and support the potential clinical application of PER2 targeting in combination with anti-PD-L1 in OSCC immunotherapy.

Keywords

head and neck neoplasms; immunotherapy; tumor escape.

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