Theranostics 2020; 10(13):5943-5956. doi:10.7150/thno.41498 This issue Cite

Research Paper

ACT001 reduces the expression of PD-L1 by inhibiting the phosphorylation of STAT3 in glioblastoma

Luqing Tong1,3,4*, Jiabo Li1,4*, Qiuying Li2, Xuya Wang1,4, Ravi Medikonda3, Tianna Zhao3, Tao Li1,4, Haiwen Ma1,4, Li Yi1,4, Peidong Liu1,3,4, Yang Xie1,4,6, John Choi3, Shengping Yu1,4, Yu Lin1,4, Jun Dong5, Qiang Huang1,4, Xun Jin6,7,8,9, Michael Lim3, Xuejun Yang1,4✉

1. Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China.
2. State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin, China.
3. Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
4. Laboratory of Neuro-oncology, Tianjin Neurological Institute, Tianjin, China.
5. Department of Neurosurgery, The Second Affiliated Hospital of Soochow University, Suzhou, China.
6. Tianjin Medical University Cancer Institute and Hospital, Tianjin, China.
7. National Clinical Research Center for Cancer, Tianjin, China.
8. Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.
9. Tianjin's Clinical Research Center for Cancer, Tianjin, China.
*Co-first authors.

Citation:
Tong L, Li J, Li Q, Wang X, Medikonda R, Zhao T, Li T, Ma H, Yi L, Liu P, Xie Y, Choi J, Yu S, Lin Y, Dong J, Huang Q, Jin X, Lim M, Yang X. ACT001 reduces the expression of PD-L1 by inhibiting the phosphorylation of STAT3 in glioblastoma. Theranostics 2020; 10(13):5943-5956. doi:10.7150/thno.41498. https://www.thno.org/v10p5943.htm
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Abstract

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ACT001, which is derived from an ancient anti-inflammatory drug, has been shown to cross the blood-brain barrier in preclinical studies and has demonstrated anti-glioblastoma (GBM) activity in clinical trials. However, its pharmacological potential for anti-GBM immune response modulation remains unclear. The chemical structure of ACT001 indicates that it may bind to STAT3 and thus modulate antitumor immune response.

Methods: Bioinformatics and immunohistochemistry (IHC) were used to assess STAT3 and PD-L1 expression in gliomas. Western blotting, RT-PCR and immunofluorescence were used to detect PD-L1 and p-STAT3 expression in glioma cells exposed to ACT001. Chromatin immunoprecipitation, an ACT001-Biotin probe, and a dual-luciferase reporter assay were used to detect direct modulation. The in vivo efficacy of ACT001 was evaluated in GL261 murine glioma model. Survival analyses were conducted using the log-rank (Mantel-Cox) test.

Results: Bioinformatic analysis of 1,837 samples from 4 public glioma datasets showed that STAT3 mRNA expression was correlated with the degree of malignancy and therapeutic resistance and that STAT3 mRNA expression was related to immunosuppression, leukocyte infiltration, and PD-L1 expression. IHC staining of 53 tissue samples confirmed that relatively high phosphorylated STAT3 and PD-L1 protein expression was associated with a relatively advanced World Health Organization (WHO) glioma grade. Next, we confirmed that ACT001 treatment reduced PD-L1 expression and STAT3 phosphorylation. An ACT001-biotin probe was used to verify that ACT001 bound to STAT3. We also demonstrated that STAT3 bound to the PD-L1 promoter. The inhibition of PD-L1 expression and STAT3 phosphorylation by ACT001 could be rescued by STAT3 overexpression. Additionally, ACT001 inhibited GBM growth and decreased PD-L1 expression in vivo. The expression of the M2 markers CD206 and CD163 was decreased, while that of the antitumor immune markers iNOS and IFNγ was increased by ACT001 in vivo.

Conclusion: Our results demonstrate that STAT3 plays a key role in immunosuppression of glioma and is inhibited by ACT001. ACT001 inhibits PD-L1 transcription and modulates anti-tumor immune response in glioma bearing mice. These findings will help us to understand the mechanism of ACT001 in GBM therapy.

Keywords: glioblastoma, ACT001, p-STAT3, PD-L1, immunosuppression


Citation styles

APA
Tong, L., Li, J., Li, Q., Wang, X., Medikonda, R., Zhao, T., Li, T., Ma, H., Yi, L., Liu, P., Xie, Y., Choi, J., Yu, S., Lin, Y., Dong, J., Huang, Q., Jin, X., Lim, M., Yang, X. (2020). ACT001 reduces the expression of PD-L1 by inhibiting the phosphorylation of STAT3 in glioblastoma. Theranostics, 10(13), 5943-5956. https://doi.org/10.7150/thno.41498.

ACS
Tong, L.; Li, J.; Li, Q.; Wang, X.; Medikonda, R.; Zhao, T.; Li, T.; Ma, H.; Yi, L.; Liu, P.; Xie, Y.; Choi, J.; Yu, S.; Lin, Y.; Dong, J.; Huang, Q.; Jin, X.; Lim, M.; Yang, X. ACT001 reduces the expression of PD-L1 by inhibiting the phosphorylation of STAT3 in glioblastoma. Theranostics 2020, 10 (13), 5943-5956. DOI: 10.7150/thno.41498.

NLM
Tong L, Li J, Li Q, Wang X, Medikonda R, Zhao T, Li T, Ma H, Yi L, Liu P, Xie Y, Choi J, Yu S, Lin Y, Dong J, Huang Q, Jin X, Lim M, Yang X. ACT001 reduces the expression of PD-L1 by inhibiting the phosphorylation of STAT3 in glioblastoma. Theranostics 2020; 10(13):5943-5956. doi:10.7150/thno.41498. https://www.thno.org/v10p5943.htm

CSE
Tong L, Li J, Li Q, Wang X, Medikonda R, Zhao T, Li T, Ma H, Yi L, Liu P, Xie Y, Choi J, Yu S, Lin Y, Dong J, Huang Q, Jin X, Lim M, Yang X. 2020. ACT001 reduces the expression of PD-L1 by inhibiting the phosphorylation of STAT3 in glioblastoma. Theranostics. 10(13):5943-5956.

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