Sir Peter MacCallum Department of Oncology - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 11
-
ItemChallenges of PD-L1 testing in non-small cell lung cancer and beyond(AME PUBL CO, 2020-08)
-
ItemNo Preview AvailableBlockade of the co-inhibitory molecule PD-1 unleashes ILC2-dependent antitumor immunity in melanoma(NATURE PORTFOLIO, 2021-07)Group 2 innate lymphoid cells (ILC2s) are essential to maintain tissue homeostasis. In cancer, ILC2s can harbor both pro-tumorigenic and anti-tumorigenic functions, but we know little about their underlying mechanisms or whether they could be clinically relevant or targeted to improve patient outcomes. Here, we found that high ILC2 infiltration in human melanoma was associated with a good clinical prognosis. ILC2s are critical producers of the cytokine granulocyte-macrophage colony-stimulating factor, which coordinates the recruitment and activation of eosinophils to enhance antitumor responses. Tumor-infiltrating ILC2s expressed programmed cell death protein-1, which limited their intratumoral accumulation, proliferation and antitumor effector functions. This inhibition could be overcome in vivo by combining interleukin-33-driven ILC2 activation with programmed cell death protein-1 blockade to significantly increase antitumor responses. Together, our results identified ILC2s as a critical immune cell type involved in melanoma immunity and revealed a potential synergistic approach to harness ILC2 function for antitumor immunotherapies.
-
ItemChimeric Antigen Receptor T cell Therapy and the Immunosuppressive Tumor Microenvironment in Pediatric Sarcoma(MDPI, 2021-09)Sarcomas are a diverse group of bone and soft tissue tumors that account for over 10% of childhood cancers. Outcomes are particularly poor for children with refractory, relapsed, or metastatic disease. Chimeric antigen receptor T (CAR T) cells are an exciting form of adoptive cell therapy that potentially offers new hope for these children. In early trials, promising outcomes have been achieved in some pediatric patients with sarcoma. However, many children do not derive benefit despite significant expression of the targeted tumor antigen. The success of CAR T cell therapy in sarcomas and other solid tumors is limited by the immunosuppressive tumor microenvironment (TME). In this review, we provide an update of the CAR T cell therapies that are currently being tested in pediatric sarcoma clinical trials, including those targeting tumors that express HER2, NY-ESO, GD2, EGFR, GPC3, B7-H3, and MAGE-A4. We also outline promising new CAR T cells that are in pre-clinical development. Finally, we discuss strategies that are being used to overcome tumor-mediated immunosuppression in solid tumors; these strategies have the potential to improve clinical outcomes of CAR T cell therapy for children with sarcoma.
-
ItemEnhancing the Potential of Immunotherapy in Paediatric Sarcomas: Breaking the Immunosuppressive Barrier with Receptor Tyrosine Kinase Inhibitors(MDPI, 2021-12)Despite aggressive surgery, chemotherapy, and radiotherapy, survival of children and adolescents and young adults (AYAs) with sarcoma has not improved significantly in the past four decades. Immune checkpoint inhibitors (ICIs) are an exciting type of immunotherapy that offer new opportunities for the treatment of paediatric and AYA sarcomas. However, to date, most children do not derive a benefit from this type of treatment as a monotherapy. The immunosuppressive tumour microenvironment is a major barrier limiting their efficacy. Combinations of ICIs, such as anti-PD-1 therapy, with targeted molecular therapies that have immunomodulatory properties may be the key to breaking through immunosuppressive barriers and improving patient outcomes. Preclinical studies have indicated that several receptor tyrosine kinase inhibitors (RTKi) can alter the tumour microenvironment and boost the efficacy of anti-PD-1 therapy. A number of these combinations have entered phase-1/2 clinical trials, mostly in adults, and in most instances have shown efficacy with manageable side-effects. In this review, we discuss the status of ICI therapy in paediatric and AYA sarcomas and the rationale for co-treatment with RTKis. We highlight new opportunities for the integration of ICI therapy with RTK inhibitors, to improve outcomes for children with sarcoma.
-
ItemNo Preview AvailableThe unexplored immune landscape of high-risk pediatric cancers.(AMER ASSOC CANCER RESEARCH, 2021-07)Abstract In adult cancer, immune signatures such as the T cell-inflamed gene expression profile (GEP) have been developed to predict which patients are likely to respond to immune checkpoint inhibitors (ICIs) beyond high tumor mutation burden (TMB) and PD-L1 expression. The GEP infers T cell infiltration and activation in the tumor microenvironment (TME) from transcriptomic data. However, it is not known whether tools such as GEP are applicable in pediatric cancer, as the TME in childhood cancers is largely unexplored and response to ICIs are rare. We have undertaken an integrated analysis of the pediatric TME using RNA-sequencing (RNA-seq) and immunohistochemistry (IHC). Our goal is to identify patients with T cell-inflamed or “hot” tumors who may benefit from ICIs. Through Australia's ZERO childhood cancer precision medicine program we performed RNA-seq on 347 high-risk pediatric cancers (estimated <30% chance of survival) and performed IHC for CD4, CD8, CD45 and PD-L1 on 112 matching samples. Using both informatic assessments and IHC as independent measures of immune infiltration, we mapped the immune landscape of the TME across a broad range of high-risk pediatric cancers. As RNA-seq is increasingly used in the analysis of patient tumors, we investigated numerous molecular correlates of immune infiltration, tailored specifically to pediatric patients. RNA-seq was used to generate the GEP and map expression profiles of immune checkpoint genes, and deconvolution algorithms were used to extract the immune cell composition for every tumor. The correlation analysis between IHC, deconvolution of cell mixture composition and GEP were assessed, including PD-L1 protein and mRNA expression. We observed significant correlation between PD-L1 protein and mRNA expression and a weak correlation of CD8+ T cells with GEP. Deconvoluted TME estimates were most tightly correlated with the presence of T cell infiltrates (CD4 and CD8) with IHC. TMB and tumor purity estimates were derived from whole genome sequencing for each case. No correlation was observed between TMB and immune infiltration, however, tumor purity was negatively correlated with immune infiltration. Using IHC as an independent marker of a T cell-inflamed TME, we have identified a novel pediatric immune signature that includes markers of CD4 and CD8 T cells, T cell cytotoxicity, T and NK cell recruitment and activation, MHC Class II molecules and immune checkpoints. This is the first study to comprehensively analyze the pediatric TME in a cohort of this size and diversity, with matching IHC for orthogonal validation. Through the combination of RNA-seq and IHC, we have devised a novel immune signature specific to pediatrics and these techniques have identified a subset of patients that are immune “hot” and may potentially respond to ICIs. Conversely, we also highlight the potential of identifying immune “cold” patients who may need immunomodulatory combination strategies to maximize immune response. Citation Format: Chelsea Mayoh, Rachael L. Terry, Marie Wong, Loretta M. Lau, Dong Anh Khuong-Quang, Marion K. Mateos, Vanessa Tyrrell, Michelle Haber, David S. Ziegler, Mark J. Cowley, Joseph A. Trapani, Paul J. Neeson, Paul G. Ekert. The unexplored immune landscape of high-risk pediatric cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3044.
-
ItemNo Preview AvailablePreclinical Evidence of the Efficacy of Lewis Y Car T Cells in Patient-Derived Models of Prostate Cancer(The Endocrine Society, 2021-05-03)Abstract Chimeric antigen receptor T (CAR T) cell therapy is an adoptive immunotherapy that has led to new treatments for lymphoma, leukemia, and other blood cancers; however, its efficacy for prostate cancer remains unproven. Here we report pre-clinical evidence of the efficacy of CAR T cell therapy against the Lewis Y antigen (LeY) using patient-derived models of prostate cancer. To assess the expression of LeY on prostate tumours, we performed immunohistochemistry on a cohort of 41 patient-derived xenografts (PDXs). Cytoplasmic and membrane expression were separately assessed and quantified, for each patient. Overall, 61% (25/41) of PDXs were positive for membrane LeY expression, of which 18 PDXs had greater than 50% membrane-positive cells, and considered most suitable to detection and stable binding by anti-LeY CAR T’s. To determine the in vitro sensitivity to CAR T cytotoxicity, we selected 4 PDXs with high and 2 PDXs with low LeY expression using 3 androgen receptor (AR)-positive adenocarcinomas and 3 AR-negative tumors expressing neuroendocrine markers. Next we established organoids for in vitro co-culture assays where organoids were co-incubated with an equal number of anti-LeY+ CAR T cells or Empty vector control CAR T cells (Ev CAR T). Using time-lapse microscopy we reported destruction of organoids by LeY+ CAR T cells as indicated by their morphological collapse and uptake of propidium iodide from the culture medium; control Ev CAR T cells produced no cytotoxicity. Over the 48h assay, the level of target cell death of the LeY+ organoids was correlated to the intensity LeY surface expression. Target cell death mediated by the CAR T cells required perforin and granzyme B, as potent and highly specific small molecule inhibitors of perforin (SN34960) and granzyme B (C20) applied alone or in combination greatly decreased PI uptake, indicating organoid survival. Neither inhibitor adversely affected CAR T cell viability as measured by PI and Annexin V staining. This demonstrated canonical activation of granule exocytosis pathway by the CAR T cells, leading to organoid cell death. To assess CAR T cell efficacy in vivo, we selected one PDX with high LeY expression. Monotherapy with CAR T cells failed to decrease tumour volume compared to vehicle control. However, CAR T cells given after a single dose of the chemotherapeutic agent carboplatin greatly and durably reduced tumour burden, with residual tumour mass being less than 1% of their original size (0.56 ± 0.23% of tumour volume at the start of treatment). Overall, these data provide preclinical evidence that: i) high membrane expression of LeY correlates with in vitro and in vivo CAR T cell-induced tumour cell death via the canonical perforin/granzyme B mechanism; and, ii) membrane LeY can be used as a biomarker for patient selection.
-
ItemNo Preview AvailableMyeloma natural killer cells are exhausted and have impaired regulation of activation(FERRATA STORTI FOUNDATION, 2021-09)Not available.
-
ItemTherapeutic strategies to remodel immunologically cold tumors(WILEY, 2020)Immune checkpoint inhibitors (ICIs) induce a durable response in a wide range of tumor types, but only a minority of patients outside these 'responsive' tumor types respond, with some totally resistant. The primary predictor of intrinsic immune resistance to ICIs is the complete or near-complete absence of lymphocytes from the tumor, so-called immunologically cold tumors. Here, we propose two broad approaches to convert 'cold' tumors into 'hot' tumors. The first is to induce immunogenic tumor cell death, through the use of oncolytic viruses or bacteria, conventional cancer therapies (e.g. chemotherapy or radiation therapy) or small molecule drugs. The second approach is to target the tumor microenvironment, and covers diverse options such as depleting immune suppressive cells; inhibiting transforming growth factor-beta; remodelling the tumor vasculature or hypoxic environment; strengthening the infiltration and activation of antigen-presenting cells and/or effector T cells in the tumor microenvironment with immune modulators; and enhancing immunogenicity through personalised cancer vaccines. Strategies that successfully modify cold tumors to overcome their resistance to ICIs represent mechanistically driven approaches that will ultimately result in rational combination therapies to extend the clinical benefits of immunotherapy to a broader cancer cohort.
-
ItemEARLY-PHENOTYPE LEWIS Y CAR-T CELLS PERSIST BETTER IN VIVO AND INDUCE SOLID TUMOR REGRESSION IN COMBINATION WITH ANTI-PD1(BMJ PUBLISHING GROUP, 2020-11)Background Chimeric antigen receptor (CAR-T) cells are a promising new therapy for patients with cancer. However, in contrast to their success in B cell malignancies, CAR-T cells targeting solid cancers have had limited success so far due to their poor proliferation and poor long-term persistence in vivo. To address this issue, we used naïve T cells to generate second-generation CAR-T cells recognizing the tumor antigen Lewis Y (LeY), termed ‘early’ CAR-T cells. Methods Purified naïve T cells were activated by CD3/CD28 soluble tetrameric antibody complex, retrovirally transduced (LeY scFv-CD3z-CD28 CAR) and expanded in IL-7/IL-15. The early LeY CAR-T cell function was tested in vitro for cytotoxicity (Cr-release and degranulation), proliferation, and cytokine secretion by CBA, either de novo or following chronic stimulation for 1 month. Finally, early CAR-T cell persistence and anti-tumor efficacy was assessed in the OVCAR3-NSG model, in the presence or absence of anti-PD-1. Results The early-CAR-T cells comprised stem cell memory-like (CD95+, CD62L+, CD45RA+) and central memory phenotype (CD95+, CD62L+, CD45RA-) T cells with increased expression of ICOS, Ki67, TCF7 and CD27 (Figure 1). The early-CAR-T cells retained potent antigen-specific cytotoxicity, and secreted significantly higher levels of cytokines (IFN-?, TNF-a and IL-2) and increased proliferation compared to conventional CAR-T cells. Importantly, early-CAR-T cells had a significantly higher proliferative capacity after long-term chronic stimulation compared to conventional CAR-T cells (figure 2), and CD4+ CAR-T cells were critical for effective early CD8+ CAR-T cell proliferation capacity in vitro (figure 3). Early CAR-T cells had significantly better in vivo tumor control compared to conventional CAR-T cells (Figure 4), this was associated with increased CAR-T cell persistence. Because chronically stimulated early-LeY-CAR-T cells expressed PD-1 (figure 2), and OVCAR-3 cells expressed PD-L1 when co-cultured with LeY-CAR-T cells (figure 5), we combined early LeY-CAR-T cells with anti-PD-1 therapy and observed complete tumour regression in these mice. Interestingly, early LeY-CAR-T cell plus anti-PD-1 treatment also enhanced the percentage of circulating stem-cell memory like CAR-T cells in vivo (figure 5). Abstract 126 Figure 1Early-CAR-T protocol, including Naïve-T cells purification and expansion in IL-7 and IL-15 promotes the maintenance of a TSCM and TCM phenotype. A) Scheme of the 7-day production protocol for Early-CAR-T cells. B) Phenotype by FACs of the conventional CAR-T cells and the Early-CAR-T cells. Pooled data in triplicate for 6 donors. C) Phenotype by Mass cytometry comparing the Conventional-CAR-T cells vs Early-CAR-T cells vs Early-CD8-CAR-T cells. Data for one donor representative of 3 different donors Abstract 126 Figure 2Early-CAR-T cells are comparable in vitro to conventional CAR-T cells in terms of killing but have a better proliferation capacity that persists after chronic stimulation. The long-term stimulated early- CAR-T cells maintain their memory phenotype and upregulated PD-1. A) Chromium release assay against the LeY+ cell line (OVCAR3), data for one donor representative of 3 other donors. B) Cytokine secretion evaluated by CBA after coculture with the LeY+ cell line (OVCAR3) or with the LeY- cell line (MDA-MB435). C) Division index of CAR-T cells quantified with CTV. D) Evaluation of the differentiation, proliferation and cytotoxicity of the CAR-T cells after chronic stimulation Abstract 126 Figure 3Early-CD4+- CAR-T cells are critical for the proliferation capacity of the Early-CD8+-CAR-T cells. A) Scheme of the CD4-depletion protocol to compare Early-CD8-CAR-T proliferation with or without CD4-T cells. B) Division index of CD4-depleted Early-CAR-T cells, CD8-T cells from bulk Early-CAR-T cells, and from CD4+ T cells from bulk Early-CAR-T-cells quantified with CTV Abstract 126 Figure 4Early-CAR-T cells show in vivo a better persistence and a better proliferation capacity associated with a better tumoral control. A) Design of the in vivo experiment (n=7 mice per group) B) T-cell persistence in peripheral blood was measured by FACS. C) Speakman correlation (Day 13) between Tumor size and% CAR-T- cells. D) Tumor kinetic and Kaplan-Meier analysis of survival of OVCAR-bearing NSG mice treated with Conventional CAR-T cells, or Early-CAR-T cells or Low-dose of Early-CAR-T cells Abstract 126 Figure 5Anti-PD1 treatment enhance the efficacy of the Early-CAR-T cells. A) Upregulation of PD-L1 on OVCAR3 when expanded in the supernatant from co-culture of OVCAR3 with LeY-CAR-T cells. B) Design of the in vivo experiment (n=7 mice per group). C) T-cell persistence, phenotype and anti-human IgG4 in peripheral blood were measured by FACS. D) Tumor kinetic of OVCAR-bearing NSG mice treated with Early-CAR-T cells or Early-CAR-T cells + Nivolumab Conclusions Our early CAR-T cells have better cytokine secretion and proliferation than conventional CAR-T cells. Early CAR-T cells also have superior anti-tumor efficacy in vivo, they have better persistence and maintain the circulating T cell memory pool. Importantly, low dose early-LeY-CAR-T cells combined with anti-PD1-treatment leads to complete clearance of LeY+ solid tumors in vivo. The early CAR-T cell production protocol is directly translatable for improving CAR-T cell efficacy in clinical trials for patients with solid tumors.
-
ItemNo Preview AvailablePVRIG is a novel natural killer cell immune checkpoint receptor in acute myeloid leukemia(FERRATA STORTI FOUNDATION, 2021-12)This study explored the novel immune checkpoint poliovirus receptor-related immunoglobulin domain-containing (PVRIG) in acute myeloid leukemia (AML). We showed that AML patient blasts consistently expressed the PVRIG ligand (poliovirus receptor-related 2, PVRL2). Furthermore, PVRIG blockade significantly enhanced NK cell killing of PVRL2+, poliovirus receptor (PVR)lo AML cell lines, and significantly increased NK cell activation and degranulation in the context of patient primary AML blasts. However, in AML patient bone marrow, NK cell PVRIG expression levels were not increased. To understand how PVRIG blockade might potentially be exploited therapeutically, we investigated the biology of PVRIG and revealed that NK cell activation resulted in reduced PVRIG expression on the cell surface. This occurred whether NK cells were activated by tumour cell recognition, cytokines (IL-2 and IL-12) or activating receptor stimulation (CD16 and NKp46). PVRIG was present at higher levels in the cytoplasm than on the cell surface, particularly on CD56bright NK cells, which further increased cytoplasmic PVRIG levels following IL-2 and IL-12 activation. PVRIG was continually transported to the cell surface via the endoplasmic reticulum (ER) and Golgi in both unstimulated and activated NK cells. Taken together, our findings suggest that anti- PVRIG blocking antibody functions by binding to surface-bound PVRIG, which undergoes rapid turnover in both unstimulated and activated NK cells. We conclude that the PVRIGPVRL2 immune checkpoint axis can feasibly be targeted with PVRIG blocking antibody for NK-mediated immunotherapy of PVRL2+ AML.