ORCID Profile
0000-0001-5884-2786
Current Organisation
Peter MacCallum Cancer Centre
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Publisher: Springer Science and Business Media LLC
Date: 18-05-2020
Publisher: American Society of Hematology
Date: 08-09-2016
DOI: 10.1182/BLOOD-2016-03-707836
Abstract: Anti-EBV TCR-like monoclonal antibodies reduce BLCLs tumor load in vivo. Anti-EBV TCR-like monoclonal antibodies mediate phagocytosis of BLCLs by macrophages.
Publisher: Springer Science and Business Media LLC
Date: 28-05-2021
DOI: 10.1038/S41467-021-23331-5
Abstract: Adenosine is an immunosuppressive factor that limits anti-tumor immunity through the suppression of multiple immune subsets including T cells via activation of the adenosine A 2A receptor (A 2A R). Using both murine and human chimeric antigen receptor (CAR) T cells, here we show that targeting A 2A R with a clinically relevant CRISPR/Cas9 strategy significantly enhances their in vivo efficacy, leading to improved survival of mice. Effects evoked by CRISPR/Cas9 mediated gene deletion of A 2A R are superior to shRNA mediated knockdown or pharmacological blockade of A 2A R. Mechanistically, human A 2A R-edited CAR T cells are significantly resistant to adenosine-mediated transcriptional changes, resulting in enhanced production of cytokines including IFNγ and TNF, and increased expression of JAK-STAT signaling pathway associated genes. A 2A R deficient CAR T cells are well tolerated and do not induce overt pathologies in mice, supporting the use of CRISPR/Cas9 to target A 2A R for the improvement of CAR T cell function in the clinic.
Publisher: Springer Science and Business Media LLC
Date: 20-04-2021
DOI: 10.1038/S41577-021-00539-6
Abstract: The antitumour activity of endogenous or adoptively transferred tumour-specific T cells is highly dependent on their differentiation status. It is now apparent that less differentiated T cells compared with fully differentiated effector T cells have better antitumour therapeutic effects owing to their enhanced capacity to expand and their long-term persistence. In patients with cancer, the presence of endogenous or adoptively transferred T cells with stem-like memory or precursor phenotype correlates with improved therapeutic outcomes. Advances in our understanding of T cell differentiation states at the epigenetic and transcriptional levels have led to the development of novel methods to generate tumour-specific T cells - namely, chimeric antigen receptor T cells - that are more persistent and resistant to the development of dysfunction. These include the use of novel culture methods before infusion, modulation of transcriptional, metabolic and/or epigenetic programming, and strategies that fine-tune antigen receptor signalling. This Review discusses existing barriers and strategies to overcome them for successful T cell expansion and persistence in the context of adoptive T cell immunotherapy for solid cancers.
Publisher: Wiley
Date: 24-05-2013
Abstract: The NOD-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome is a cytoplasmic protein complex that mediates inflammatory responses to a broad array of danger signals. The inflammasome drives caspase-1 activation and promotes secretion of the pro-inflammatory cytokines IL-1β and IL-18, and might also participate in other cellular processes. Here, we tried to identify new pathways regulated by the NLRP3 inflammasome in murine dendritic cells (DCs) in response to monosodium urate (MSU) crystals. Using a transcriptomic approach, we found that DCs from Nlrp3(-/-) mice responded to MSU with differential expression of genes involved in the DNA damage response and apoptosis. Upon exposure to MSU or other ROS-mobilizing stimuli (rotenone and γ-radiation), DNA fragmentation was markedly ameliorated in Nlrp3(-/-) and casp-1(-/-) DCs compared with WT DCs. Moreover, Nlrp3(-/-) DCs experienced significantly less oxidative DNA damage mediated by ROS. A significant decrease of the expression of several genes involved in double-strand and base-excision DNA repair was observed in WT DCs. Basal DNA repair capacity in WT DCs resulted in activation and stabilization of p53 in vitro and in vivo, which resulted in increased cell death compared with that in Nlrp3(-/-) DCs. These data provide the first evidence for the involvement of the NLRP3 inflammasome in DNA damage responses induced by cellular stress.
Publisher: American Association for Cancer Research (AACR)
Date: 12-2021
DOI: 10.1158/0008-5472.CAN-21-3548
Abstract: Cancer immunotherapy utilizing checkpoint blockade antibodies or adoptive cellular therapy (ACT) with tumor-specific T cells has led to unprecedented clinical responses in patients with cancer and has been considered one of the most significant breakthroughs in cancer treatment in the past decade. Nevertheless, many cancers remain refractory to these therapies due to the presence of an immunosuppressive tumor microenvironment. This has led to the innovative idea of combining ACT with checkpoint inhibition. A landmark 2004 study by Blank and colleagues published in Cancer Research was one of the original demonstrations that adoptive transfer of T cells lacking the negative T-cell regulator, PD-1, was able to restore functional T-cell antitumor activity, resulting in rapid regression of established tumors in a preclinical model. This work was instrumental in not only driving clinical studies utilizing checkpoint inhibition but also a new wave of recent trials involving checkpoint blockade in the setting of ACT. See related article by Blank and colleagues, Cancer Res 2004 :1140–5
Publisher: American Association for Cancer Research (AACR)
Date: 15-01-2020
DOI: 10.1158/1078-0432.CCR-19-1868
Abstract: Response rates to immune checkpoint blockade (ICB anti-PD-1/anti-CTLA-4) correlate with the extent of tumor immune infiltrate, but the mechanisms underlying the recruitment of T cells following therapy are poorly characterized. A greater understanding of these processes may see the development of therapeutic interventions that enhance T-cell recruitment and, consequently, improved patient outcomes. We therefore investigated the chemokines essential for immune cell recruitment and subsequent therapeutic efficacy of these immunotherapies. The chemokines upregulated by dual PD-1/CTLA-4 blockade were assessed using NanoString-based analysis with results confirmed at the protein level by flow cytometry and cytometric bead array. Blocking/neutralizing antibodies confirmed the requirement for key chemokines/cytokines and immune effector cells. Results were confirmed in patients treated with immune checkpoint inhibitors using single-cell RNA-sequencing (RNA-seq) and paired survival analyses. The CXCR3 ligands, CXCL9 and CXCL10, were significantly upregulated following dual PD-1/CTLA-4 blockade and both CD8+ T-cell infiltration and therapeutic efficacy were CXCR3 dependent. In both murine models and patients undergoing immunotherapy, macrophages were the predominant source of CXCL9 and their depletion abrogated CD8+ T-cell infiltration and the therapeutic efficacy of dual ICB. Single-cell RNA-seq analysis of patient tumor-infiltrating lymphocytes (TIL) revealed that CXCL9/10/11 was predominantly expressed by macrophages following ICB and we identified a distinct macrophage signature that was associated with positive responses to ICB. These data underline the fundamental importance of macrophage-derived CXCR3 ligands for the therapeutic efficacy of ICB and highlight the potential of manipulating this axis to enhance patient responses.
Publisher: Frontiers Media SA
Date: 07-04-2021
Abstract: Epstein-Barr virus (EBV)—the prototypical human tumor virus—is responsible for 1–2% of the global cancer burden, but ergent strains seem to exist in different geographical regions with distinct predilections for causing lymphoid or epithelial malignancies. Here we report the establishment and characterization of Yu103, an Asia Pacific EBV strain with a highly remarkable provenance of being derived from nasopharyngeal carcinoma biopsy but subsequently propagated in human B-lymphoma cells and xenograft models. Unlike previously characterized EBV strains which are either predominantly B-lymphotropic or epitheliotropic, Yu103 evinces an uncanny capacity to infect and transform both B-lymphocytes and nasopharyngeal epithelial cells. Genomic and phylogenetic analyses indicated that Yu103 EBV lies midway along the spectrum of EBV strains known to drive lymphomagenesis or carcinogenesis, and harbors molecular features which likely account for its unusual properties. To our knowledge, Yu103 EBV is currently the only EBV isolate shown to drive human nasopharyngeal carcinoma and B-lymphoma, and should therefore provide a powerful novel platform for research on EBV-driven hematological and epithelial malignancies.
Publisher: American Association for Cancer Research (AACR)
Date: 09-2018
DOI: 10.1158/2326-6066.CIR-18-0291
Abstract: Immunotherapy is widely accepted as a powerful new treatment modality for the treatment of cancer. The most successful form of immunotherapy to date has been the blockade of the immune checkpoints PD-1 and CTLA-4. Combining inhibitors of both PD-1 and CTLA-4 increases the proportion of patients who respond to immunotherapy. However, most patients still do not respond to checkpoint inhibitors, and prognostic biomarkers are currently lacking. Therefore, a better understanding of the mechanism by which these checkpoint inhibitors enhance antitumor immune responses is required to more accurately predict which patients are likely to respond and further enhance this treatment modality. Our current study of two mouse tumor models revealed that CD4+Foxp3− cells activated by dual PD-1/CTLA-4 blockade modulated the myeloid compartment, including activation of conventional CD103+ dendritic cells (DC) and expansion of a myeloid subset that produces TNFα and iNOS (TIP-DCs). CD4+Foxp3− T cell–mediated activation of CD103+ DCs resulted in enhanced IL12 production by these cells and IL12 enhanced the therapeutic effect of dual PD-1/CTLA-4 blockade. Given the importance of these myeloid subsets in the antitumor immune response, our data point to a previously underappreciated role of CD4+Foxp3− cells in modulating this arm of the antitumor immune response. Cancer Immunol Res 6(9) 1069–81. ©2018 AACR.
Publisher: Springer Science and Business Media LLC
Date: 06-08-2021
DOI: 10.1038/S41467-021-25009-4
Abstract: The function of MR1-restricted mucosal-associated invariant T (MAIT) cells in tumor immunity is unclear. Here we show that MAIT cell-deficient mice have enhanced NK cell-dependent control of metastatic B16F10 tumor growth relative to control mice. Analyses of this interplay in human tumor s les reveal that high expression of a MAIT cell gene signature negatively impacts the prognostic significance of NK cells. Paradoxically, pre-pulsing tumors with MAIT cell antigens, or activating MAIT cells in vivo, enhances anti-tumor immunity in B16F10 and E0771 mouse tumor models, including in the context of established metastasis. These effects are associated with enhanced NK cell responses and increased expression of both IFN-γ-dependent and inflammatory genes in NK cells. Importantly, activated human MAIT cells also promote the function of NK cells isolated from patient tumor s les. Our results thus describe an activation-dependent, MAIT cell-mediated regulation of NK cells, and suggest a potential therapeutic avenue for cancer treatment.
Publisher: MDPI AG
Date: 18-02-2021
Abstract: Chimeric antigen receptor T cells (CAR-T) utilize T cell receptor (TCR) signaling cascades and the recognition functions of antibodies. This allows T cells, normally restricted by the major histocompatibility complex (MHC), to be redirected to target cells by their surface antigens, such as tumor associated antigens (TAAs). CAR-T technology has achieved significant successes in treatment of certain cancers, primarily liquid cancers. Nonetheless, many challenges hinder development of this therapy, such as cytokine release syndrome (CRS) and the efficacy of CAR-T treatments for solid tumors. These challenges show our inadequate understanding of this technology, particularly regarding CAR signaling, which has been less studied. To dissect CAR signaling, we designed a CAR that targets an epitope from latent membrane protein 2 A (LMP2 A) of the Epstein–Barr virus (EBV) presented on HLA*A02:01. Because of this, CAR and TCR signaling can be compared directly, allowing us to study the involvement of other signaling molecules, such as coreceptors. This comparison revealed that CAR was sufficient to bind monomeric antigens due to its high affinity but required oligomeric antigens for its activation. CAR sustained the transduced signal significantly longer, but at a lower magnitude, than did TCR. CD8 coreceptor was recruited to the CAR synapse but played a negligible role in signaling, unlike for TCR signaling. The distinct CAR signaling processes could provide explanations for clinical behavior of CAR-T therapy and suggest ways to improve the technology.
Publisher: Springer Science and Business Media LLC
Date: 30-08-2017
DOI: 10.1038/S41598-017-10265-6
Abstract: Epstein-Barr virus (EBV) is a common gammaherpesvirus associated with various human malignancies. Antibodies with T cell receptor-like specificities (TCR-like mAbs) provide a means to target intracellular tumor- or virus-associated antigens by recognising their processed peptides presented on major histocompatibility complex (MHC) class I (pMHC) complexes. These antibodies are however thought to be relevant only for a single HLA allele. Here, we show that HLA-A*02:01-restricted EBV antigenic peptides EBNA1 562-570 , LMP1 125-133 and LMP2A 426-434 display binding degeneracy towards HLA-A*02 allelic microvariants, and that these pMHC complexes are recognised by anti-EBV TCR-like mAbs E1, L1 and L2 raised in the context of HLA-A*02:01. These antibodies bound endogenously derived pMHC targets on EBV–transformed human B lymphoblastoid cell lines expressing A*02:01, A*02:03, A*02:06 and A*02:07 alleles. More importantly, these TCR-like mAbs mediated both complement-dependent and antibody-dependent cellular cytotoxicity of these cell lines in vitro . This finding suggests the utility of TCR-like mAbs against target cells of closely related HLA subtypes, and the potential applicability of similar reagents within populations of erse HLA-A*02 alleles.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Springer Science and Business Media LLC
Date: 18-11-2013
DOI: 10.1038/SREP03232
Abstract: Epstein-Barr virus (EBV) is a gamma herpesvirus that causes a life-long latent infection in human hosts. The latent gene products LMP1, LMP2A and EBNA1 are expressed by EBV-associated tumors and peptide epitopes derived from these can be targeted by CD8 Cytotoxic T-Lymphocyte (CTL) lines. Whilst CTL-based methodologies can be utilized to infer the presence of specific latent epitopes, they do not allow a direct visualization or quantitation of these epitopes. Here, we describe the characterization of three TCR-like monoclonal antibodies (mAbs) targeting the latent epitopes LMP1 125–133 , LMP2A 426–434 or EBNA1 562–570 in association with HLA-A0201. These are employed to map the expression hierarchy of endogenously generated EBV epitopes. The dominance of EBNA1 562–570 in association with HLA-A0201 was consistently observed in cell lines and EBV-associated tumor biopsies. These data highlight the discordance between MHC-epitope density and frequencies of associated CTL with implications for cell-based immunotherapies and/or vaccines for EBV-associated disease.
Publisher: Wiley
Date: 2019
DOI: 10.1002/CTI2.1046
Start Date: 2011
End Date: 2015
Funder: National University of Singapore
View Funded ActivityStart Date: 2021
End Date: 2023
Funder: Cancer Research Institute
View Funded ActivityStart Date: 2022
End Date: 2023
Funder: Peter MacCallum Cancer Centre
View Funded ActivityStart Date: 2022
End Date: 2024
Funder: National Health and Medical Research Council
View Funded Activity