Elsevier

Journal of Controlled Release

Volume 320, 10 April 2020, Pages 63-72
Journal of Controlled Release

Deliver anti-PD-L1 into brain by p-hydroxybenzoic acid to enhance immunotherapeutic effect for glioblastoma

https://doi.org/10.1016/j.jconrel.2020.01.005Get rights and content

Abstract

In glioblastoma with typical immunosuppressive characteristics, immune checkpoint inhibitors treatment showed unsatisfactory clinical effects, attributable to the exclusion of antibodies by blood-brain barrier (BBB) to a large extent. Herein, a conjugate of anti-programmed death ligand 1 antibody (αPDL1) and the targeting moiety p-hydroxybenzoic acid (pHA) was designed to realize crossing BBB of antibody based on the dopamine receptor mediated transcytosis. Conjugation with pHA did not influence the binding affinity of αPDL1 with PD-L1 protein, thus maintaining the capability of PD pathway blockade. Importantly, pHA-αPDL1 crossed BBB, demonstrated by the increased distribution in both the brain and the glioma after intravenous administration of pHA-αPDL1. Compared with the unmodified αPDL1, pHA-αPDL1 prolonged the survival time and suppressed tumor growth more effectively in an orthotopic glioblastoma model by activating glioma-infiltrating T cells. Our results suggested the potential of the antibody-pHA conjugate to improve efficacy for cerebral diseases by providing a potential platform for macromolecules to play therapeutics role in the brain.

Introduction

Glioblastoma (GBM) is the most common and deadly primary malignant intracranial tumor. Due to its poor prognosis, the current standard care, which usually combines surgical resection and chemoradiation, rarely effectively improves the median overall survival and 5-year survival rate [1,2].

Since the lymphatic drainage system has been proven to exist in brain [3,4], immunotherapy becomes a promising approach for brain tumor treatment, especially for glioma with typical cancer-associated immunosuppression [[5], [6], [7], [8]]. In GBM, signal transducer and activator of transcription 3 (STAT3) pathway upregulates expression of interleukin-10 (IL-10), interleukin-6 (IL-6) and transforming growth factor-β (TGF-β), but limits the capacity of dendritic cell (DC) of tumor associated antigen presentation, thus inducing recruitment of regulatory phenotype T cells (Treg) and suppressing T effector cells. Furthermore, under the impact of suppressing cytokines such as TGF-β and IFN-γ, programmed cell death 1 ligand 1 (PD-L1) is overexpressed in glioblastoma, activating programmed death 1 receptor (PD-1) and inducing the apoptosis and anergy of T effector cells. Besides, immunosuppression is not confined to tumor microenvironment [9], which might also be related to PD-L1 over expression on tumor-derived extracellular vesicles [10].

So far, extensively immunotherapeutic approaches [9] have been investigated, including immune checkpoint inhibitors [11,12], vaccines [13], chimeric antigen receptor T-cells [14] and oncolytic viruses [15], etc. Immune checkpoint blockade, by antibodies against PD-1, cytotoxic T lymphocyte antigen 4 (CTLA-4) or PD-L1, has been proven effective for many solid tumors [[16], [17], [18]]. However, in clinical trials for GBM [[19], [20], [21]], combination of nivolumab and ipilimumab ended with severe immune-related adverse effects [22,23], and avelumab (anti-PD-L1 antibody) made only negligible improvements on the progression-free survival [24], though higher PD-L1 expression is usually related with effective immunotherapy in the peripheral solid tumors [25]. In contrast, checkpoint inhibitors were partially effective for the treatment of brain metastases clinically [26,27]. Although it remains unclear for exact underlying mechanisms of such variation in clinical response. Disrupted BBB induced by metastatic lesions might be one of reasonable explanation [28]. Indeed, the major obstacle for immunotherapy for glioma is the presence of BBB that restricts the entry of checkpoint inhibitors into the brain [28,29]. So effective delivery of antibody across BBB into brain is crucial for enhancing its efficacy.

Benzamide analogues have been proven to be able to cross the BBB mediated by D1 and D2 dopamine receptors [30] that prominently exist in most parts of the central nervous system. p-Hydroxybenzoic acid (pHA), one of benzamide analogues, has been successfully applied as the brain-targeting ligand for delivery systems [31,32].

In the present study, the conjugate of anti-PDL1 antibody and pHA was designed for immunotherapy of glioma (Fig. 1), which was expected to have affinity for CD274 protein (PD-L1), and capability of BBB-crossing, to provide new possibility of macromolecules for treatment of brain disease.

Section snippets

Materials, mice and cell lines

The anti-PDL1 antibody (αPDL1) was purchased from Biolegend (Clone: 10F.9G2, USA). p-Hydroxybenzoic acid (pHA) was from Sigma-Aldrich (St.Louis, Mo). 4-(N-Maleimidomethyl)cyclohexane-1-carboxylic acid 3-sulfo-N-hydroxysuccinimide ester sodium salt (Sulfo-SMCC) was provided by Meilunbio (China). Spin Desalting Columns (7 K MWCO) were purchased by Thermo Fisher (USA). CD274 protein was purchased from Sino Biological (China). Dopamine (DA) was purchased from Meilunbio (China). Murine IFN-gamma was

Preparation and characterization of pHA-αPDL1 conjugate

The pHA-αPDL1 conjugate was synthesized via covalently conjugation of the activated amino group in αPDL1 with the sulfhydryl group introduced in pHA via the maleimide linker (Fig. 2A). The sulfhydryl group of pHA was attached with exposed maleimide groups of the activated antibody. MALDI-TOF (Fig. 2B) showed that the conjugation was successful with one monoclonal αPDL1 modified with an average of six pHA molecules. Furthermore, the increase in the molecular weight displayed by SDS-PAGE (Fig. 2

Conclusion

pHA-αPDL1 was developed to deliver anti-PD-L1 antibody into brain for treatment of glioma. pHA decoration on αPDL1 did not impair its binding affinity with PD-L1 protein and its capability of blocking immune checkpoints. Addition of brain-targeting properties assisted αPDL1 to cross BBB, consequently increasing its distribution into the brain as well as the glioma. Furthermore, intravenous pHA-αPDL1 administration prolonged the survival time of glioma-bearing mice by alleviating

Acknowledgements

This work was supported by National Natural Science Foundation of China (No.81690263), Shanghai Education Commission Major Project (2017-01-07-00-07-E00052) and National Basic Research Program of China (973 Program, No.2013CB932500).

References (53)

  • S. Rahimian et al.

    Polymeric microparticles for sustained and local delivery of antiCD40 and antiCTLA-4 in immunotherapy of cancer

    Biomaterials

    (2015)
  • Cloughesy BMAaTF

    Adult Glioblastoma

    J. Clin. Oncol.

    (2017)
  • K. Braun et al.

    Treatment of Glioblastoma in older adults

    Curr. Oncol. Rep.

    (2017)
  • A. Louveau et al.

    Structural and functional features of central nervous system lymphatic vessels

    Nature

    (2015)
  • A. Aspelund et al.

    A dural lymphatic vascular system that drains brain interstitial fluid and macromolecules

    J. Exp. Med.

    (2015)
  • E.K. Nduom et al.

    Immunosuppressive mechanisms in glioblastoma: Fig. 1

    Neuro-Oncology

    (2015)
  • N.F. Brown et al.

    Harnessing the immune system in glioblastoma

    Br. J. Cancer

    (2018)
  • W. Tomaszewski et al.

    Brain tumor microenvironment and host state: implications for immunotherapy

    Clin. Cancer Res.

    (2019)
  • M. Lim et al.

    Current state of immunotherapy for glioblastoma

    Nat. Rev. Clin. Oncol.

    (2018)
  • F.L. Ricklefs et al.

    Immune evasion mediated by PD-L1 on glioblastoma-derived extracellular vesicles

    Sci. Adv.

    (2018)
  • D.A. Wainwright et al.

    Durable therapeutic efficacy utilizing combinatorial blockade against IDO, CTLA-4, and PD-L1 in mice with brain tumors

    Clin. Cancer Res.

    (2014)
  • S. Sau et al.

    PDL-1 antibody drug conjugate for selective chemo-guided immune modulation of cancer

    Cancers (Basel)

    (2019)
  • Z. Kong et al.

    Vaccination in the immunotherapy of glioblastoma

    Hum. Vacc. Immunother.

    (2018)
  • H. Samaha et al.

    A homing system targets therapeutic T cells to brain cancer

    Nature

    (2018)
  • A. Samson et al.

    Intravenous delivery of oncolytic reovirus to brain tumor patients immunologically primes for subsequent checkpoint blockade

    Sci. Transl. Med.

    (2018)
  • Y.J. Park et al.

    Future prospects of immune checkpoint blockade in cancer: from response prediction to overcoming resistance

    Exp. Mol. Med.

    (2018)
  • Cited by (0)

    View full text