ORCID Profile
0000-0003-2695-3849
Current Organisation
Mater Research Institute The University of Queensland
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Publisher: American Society of Hematology
Date: 19-12-2019
Abstract: This article reports a novel mechanism by which Epstein-Barr virus (EBV) microRNA (miRNA) plays a role to fine-tune the expression of LMP1-driven lification of inhibitory checkpoint programmed death ligand 1 (PD-L1) and PD-L2 in EBV+ diffuse large B-cell lymphoma. Identification and understanding of the immune checkpoint regulation via miRNA may enable potential novel RNA-based therapies to emerge.
Publisher: Springer Science and Business Media LLC
Date: 16-02-2014
DOI: 10.1038/NG.2900
Abstract: Classical Hodgkin lymphoma and primary mediastinal B cell lymphoma (PMBCL) are related lymphomas sharing pathological, molecular and clinical characteristics. Here we discovered by whole-genome and whole-transcriptome sequencing recurrent somatic coding-sequence mutations in the PTPN1 gene. Mutations were found in 6 of 30 (20%) Hodgkin lymphoma cases, in 6 of 9 (67%) Hodgkin lymphoma-derived cell lines, in 17 of 77 (22%) PMBCL cases and in 1 of 3 (33%) PMBCL-derived cell lines, consisting of nonsense, missense and frameshift mutations. We demonstrate that PTPN1 mutations lead to reduced phosphatase activity and increased phosphorylation of JAK-STAT pathway members. Moreover, silencing of PTPN1 by RNA interference in Hodgkin lymphoma cell line KM-H2 resulted in hyperphosphorylation and overexpression of downstream oncogenic targets. Our data establish PTPN1 mutations as new drivers in lymphomagenesis.
Publisher: American Society for Microbiology
Date: 03-2010
DOI: 10.1128/IAI.00156-09
Abstract: Meningococcal porin PorB is an inhibitor of apoptosis induced via the intrinsic pathway in various cell types. This effect is attributed to prevention of mitochondrial depolarization and of subsequent release of proapoptotic mitochondrial factors. To determine whether apoptosis is globally inhibited by PorB, we compared the intrinsic and extrinsic pathways in HeLa cells. Interestingly, PorB does not prevent extrinsic apoptosis induced by tumor necrosis factor alpha plus cycloheximide, suggesting a unique mitochondrial pathway specificity. Several intracellular factors regulated by NF-κB, including members of the Bcl-2 family and of the inhibitor of apoptosis (IAP) family, play major roles in controlling apoptosis, and some of them are thought to contribute to the antiapoptotic effect of the gonococcal porin, PIB. However, most of the members of the Bcl-2 family and the IAP family are not induced by meningococcal PorB in HeLa cells, with the exception of Bfl-1/A1. Interestingly, PorB does not induce NF-κB activation in HeLa cells, likely due to a lack of Toll-like receptor 2 (TLR2) expression in these cells. Bfl-1/A1 expression is also regulated by CBF1, a nuclear component of the Notch signaling pathway, independent of NF-κB activation. Since HeLa cells are protected by PorB from intrinsic apoptosis events, regardless of TLR2 and NF-κB expression, the possibility of a contribution of alternative signaling pathways to this effect cannot be excluded. In this paper, we describe an initial dissection of the cascade of cellular events involved in the antiapoptotic effect of PorB in the absence of TLR2.
Publisher: American Diabetes Association
Date: 11-05-2012
DOI: 10.2337/DC11-2114
Abstract: To determine tissue factor procoagulant activity (TF-PCA) in patients with type 1 diabetes and to examine effects of hyperglycemia and hyperglycemia plus hyperinsulinemia on TF-PCA. We have determined circulating TF-PCA and other coagulation factors under basal (hyperglycemic) conditions, after acute correction of hyperglycemia, in response to 24 h of selective hyperglycemia, and in response to 24 h of hyperglycemia plus hyperinsulinemia in nine type 1 diabetic patients and in seven nondiabetic control subjects. As shown previously in patients with type 2 diabetes, basal TF-PCA and plasma coagulation factor VIIa (FVIIa) were higher in patients with type 1 diabetes than in nondiabetic control subjects. However, in contrast with type 2 diabetes, normalizing glucose did not decrease the elevated TF-PCA levels, and raising glucose or glucose plus insulin levels did not increase TF-PCA. Patients with type 1 diabetes have elevated circulating TF-PCA and FVIIa levels and are in a procoagulant state that may predispose them to acute cardiovascular events. The mechanisms regulating TF-PCA in patients with type 1 and type 2 diabetes are different and should be further explored.
Publisher: American Society of Hematology
Date: 03-05-2018
DOI: 10.1182/BLOOD-2017-09-808907
Abstract: Somatic IL4R mutations were identified in 24% of primary PMBCL cases (n = 62) and in 100% of PMBCL-derived cell lines. IL4R mutations lead to hyperphosphorylation of STAT proteins activating downstream immunoregulatory genes (CD23, CCL17).
Publisher: Wiley
Date: 24-07-2019
DOI: 10.1111/EJH.13274
Abstract: Epstein‐Barr virus‐positive diffuse large B‐cell lymphoma (EBV ‐pos DLBCL) is a recently identified entity. Data regarding outcome to frontline immuno‐chemotherapy are conflicting. Although the prognostic impact of the tumour microenvironment (TME) in EBV ‐neg DLBCL is well‐established, it remains untested whether the TME influences survival in EBV ‐pos DLBCL. There are no data with new digital gene expression technologies that simultaneously interrogate the virus, B cells and the tumour microenvironment (TME). We used the NanoString™ platform in a population‐based cohort of 433 patients to establish if the technology could detect EBV in the tumour biopsies and to investigate the influence that EBV has on the complex tumour microenvironment of DLBCL. Incidence of EBV ‐pos DLBCL was 6.9% with 5‐year survival of 65% vs 82% in EBV ‐neg DLBCL ( P = 0.018). EBV ‐pos tissues had similar expression of T‐cell genes compared to EBV ‐neg DLBCL but higher levels of the antigen‐presenting molecule B2M. This was countered by elevated PD‐L1, PD‐L2, LAG3 and TIM3 immune checkpoints and a higher CD163/CD68 “M2” macrophage score. In EBV ‐pos DLBCL, the TME is immuno‐tolerogenic and may explain the poor outcomes seen in this subtype of DLBCL.
Publisher: American Society of Clinical Oncology (ASCO)
Date: 20-02-2020
DOI: 10.1200/JCO.19.02935
Publisher: American Society of Clinical Oncology (ASCO)
Date: 12-2019
DOI: 10.1200/JCO.18.02365
Abstract: Understanding the immunobiology of the 15% to 30% of patients with follicular lymphoma (FL) who experience progression of disease within 24 months (POD24) remains a priority. Solid tumors with low levels of intratumoral immune infiltration have inferior outcomes. It is unknown whether a similar relationship exists between POD24 in FL. Digital gene expression using a custom code set—five immune effector, six immune checkpoint, one macrophage molecules—was applied to a discovery cohort of patients with early- and advanced-stage FL (n = 132). T-cell receptor repertoire analysis, flow cytometry, multispectral immunofluorescence, and next-generation sequencing were performed. The immune infiltration profile was validated in two independent cohorts of patients with advanced-stage FL requiring systemic treatment (n = 138, rituximab plus cyclophosphamide, vincristine, prednisone n = 45, rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone), with the latter selected to permit comparison of patients experiencing a POD24 event with those having no progression at 5 years or more. Immune molecules showed distinct clustering, characterized by either high or low expression regardless of categorization as an immune effector, immune checkpoint, or macrophage molecule. Low programmed death-ligand 2 (PD-L2) was the most sensitive/specific marker to segregate patients with adverse outcomes therefore, PD-L2 expression was chosen to distinguish immune infiltration HI (ie, high PD-L2) FL biopsies from immune infiltration LO (ie, low PD-L2) tumors. Immune infiltration HI tissues were highly infiltrated with macrophages and expanded populations of T-cell clones. Of note, the immune infiltration LO subset of patients with FL was enriched for POD24 events (odds ratio [OR], 4.32 c-statistic, 0.81 P = .001), validated in the independent cohorts (rituximab plus cyclophosphamide, vincristine, prednisone: OR, 2.95 c-statistic, 0.75 P = .011 and rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone: OR, 7.09 c-statistic, 0.88 P = .011). Mutations were equally proportioned across tissues, which indicated that degree of immune infiltration is capturing aspects of FL biology distinct from its mutational profile. Assessment of immune-infiltration by PD-L2 expression is a promising tool with which to help identify patients who are at risk for POD24.
Publisher: American Society of Hematology
Date: 18-03-2021
Abstract: Primary central nervous system lymphoma (PCNSL) is confined to the brain, eyes, and cerebrospinal fluid without evidence of systemic spread. Rarely, PCNSL occurs in the context of immunosuppression (eg, posttransplant lymphoproliferative disorders or HIV [AIDS-related PCNSL]). These cases are poorly characterized, have dismal outcome, and are typically Epstein-Barr virus (EBV)-associated (ie, tissue-positive). We used targeted sequencing and digital multiplex gene expression to compare the genetic landscape and tumor microenvironment (TME) of 91 PCNSL tissues all with diffuse large B-cell lymphoma histology. Forty-seven were EBV tissue-negative: 45 EBV− HIV− PCNSL and 2 EBV− HIV+ PCNSL and 44 were EBV tissue-positive: 23 EBV+ HIV+ PCNSL and 21 EBV+ HIV− PCNSL. As with prior studies, EBV− HIV− PCNSL had frequent MYD88, CD79B, and PIM1 mutations, and enrichment for the activated B-cell (ABC) cell-of-origin subtype. In contrast, these mutations were absent in all EBV tissue-positive cases and ABC frequency was low. Furthermore, copy number loss in HLA class I/II and antigen-presenting rocessing genes were rarely observed, indicating retained antigen presentation. To counter this, EBV+ HIV− PCNSL had a tolerogenic TME with elevated macrophage and immune-checkpoint gene expression, whereas AIDS-related PCNSL had low CD4 gene counts. EBV-associated PCNSL in the immunosuppressed is immunobiologically distinct from EBV− HIV− PCNSL, and, despite expressing an immunogenic virus, retains the ability to present EBV antigens. Results provide a framework for targeted treatment.
Publisher: American Society of Hematology
Date: 22-06-2021
DOI: 10.1182/BLOODADVANCES.2020004051
Abstract: Data on the prognostic impact of pretherapy 18F-fluorodeoxyglucose–positron emission tomography (FDG-PET) in follicular lymphoma (FL) is conflicting. The predictive utility of pretherapy total metabolic tumor volume (TMTV) and maximum standardized uptake value (SUVmax) on outcome appears to vary between regimens. Chemoimmunotherapies vary in the extent of T-cell depletion they induce. The role of intratumoral T cells on pretherapy FDG-PET parameters is undefined. We assessed pretherapy FDG-PET parameters and quantified intratumoral T cells by multiple methodologies. Low intratumoral T cells associated with approximately sixfold higher TMTV, and FL nodes from patients with high TMTV showed increased malignant B-cell infiltration and fewer clonally expanded intratumoral CD8+ and CD4+ T-follicular helper cells than those with low TMTV. However, fluorescently labeled glucose uptake was higher in CD4+ and CD8+ T cells than intratumoral B cells. In patients with FDG-PET performed prior to excisional biopsy, SUVmax within the subsequently excised node associated with T cells but not B cells. In summary, TMTV best reflects the malignant B-cell burden in FL, whereas intratumoral T cells influence SUVmax. This may contribute to the contradictory results between the prognostic role of different FDG-PET parameters, particularly between short- and long-term T-cell–depleting chemoimmunotherapeutic regimens. The impact of glucose uptake in intratumoral T cells should be considered when interpreting pretherapy FDG-PET in FL.
Publisher: Wiley
Date: 21-05-2012
Publisher: The American Association of Immunologists
Date: 15-02-2006
DOI: 10.4049/JIMMUNOL.176.4.2373
Abstract: TLR2 plays a key role in the initiation of the cellular innate immune responses by a wide range of bacterial products. TLRs signaling, including TLR2 and its coreceptors TLR1 and TLR6, is mediated by a number of specific ligands. Although many of the TLR-mediated cell signaling pathways have been elucidated in the past few years, the molecular mechanisms that lead to cell activation are still poorly understood. In this study, we investigate the interaction of PorB from Neisseria meningitidis with TLR2 and describe the direct binding of a bacterial protein to TLR2 for the first time. Using labeled PorB, we demonstrate its binding to TLR2 both in its soluble form in vitro, and when it is over-expressed on the surface of human embryonic kidney 293 cells. We also show that TLR2-mediated binding of PorB is directly related to cellular activation. In addition, using 293 cells expressing the chimeric TLR2/TLR1 and TLR2/TLR6 complexes, we report the selectivity of PorB binding to the TLR2/TLR1 heterodimer, which is required for initiating signaling in transfected 293 cells and in murine B cells. Together, these data provide new evidence that TLR2 recognizes PorB through direct binding, and that PorB-induced cell activation is mediated by a TLR2/TLR1 complex.
Publisher: American Society for Microbiology
Date: 08-2015
DOI: 10.1128/IAI.00627-15
Publisher: American Society of Hematology
Date: 03-2012
DOI: 10.1182/BLOOD-2011-11-391474
Abstract: Mantle cell lymphoma (MCL), an aggressive subtype of non-Hodgkin lymphoma, is characterized by the hallmark translocation t(11 )(q13 q32) and the resulting overexpression of cyclin D1 (CCND1). Our current knowledge of this disease encompasses frequent secondary cytogenetic aberrations and the recurrent mutation of a handful of genes, such as TP53, ATM, and CCND1. However, these findings insufficiently explain the biologic underpinnings of MCL. Here, we performed whole transcriptome sequencing on a discovery cohort of 18 primary tissue MCL s les and 2 cell lines. We found recurrent mutations in NOTCH1, a finding that we confirmed in an extension cohort of 108 clinical s les and 8 cell lines. In total, 12% of clinical s les and 20% of cell lines harbored somatic NOTCH1 coding sequence mutations that clustered in the PEST domain and predominantly consisted of truncating mutations or small frame-shifting indels. NOTCH1 mutations were associated with poor overall survival (P = .003). Furthermore, we showed that inhibition of the NOTCH pathway reduced proliferation and induced apoptosis in 2 MCL cell lines. In summary, we have identified recurrent NOTCH1 mutations that provide the preclinical rationale for therapeutic inhibition of the NOTCH pathway in a subset of patients with MCL.
Publisher: Elsevier BV
Date: 10-2021
DOI: 10.1111/AJT.16628
Abstract: Primary central nervous system lymphoma (PCNSL) occurring following organ transplantation (post-transplantation lymphoproliferative disorder [PTLD]) is a highly aggressive non-Hodgkin lymphoma. It is typically treated with high-dose methotrexate-based regimens. Outcomes are dismal and clinical trials are lacking. It is almost always Epstein-Barr virus (EBV) associated. Two patients (CA1-2) presented with EBV-associated PCNSL after renal transplant. CA1 was on hemodialysis and had prior disseminated cryptococcus and pseudomonas bronchiectasis, precluding treatment with methotrexate. CA2 was refractory to methotrexate. Both were treated off-label with the first-generation Bruton's tyrosine kinase inhibitor ibrutinib for 12 months. Cerebrospinal fluid penetration at therapeutic levels was confirmed in CA1 despite hemodialysis. Both patients entered remission by 2 months. Sequencing confirmed absence of genetic aberrations in human leukocyte antigen (HLA) class I/II and antigen-presentation rocessing genes, indicating retention of the ability to present EBV-antigens. Between Weeks 10 and 13, they received third-party EBV-specific T cells for consolidation with no adverse effects. They remain in remission ≥34 months since therapy began. The strength of these findings led to an ongoing phase I study (ACTRN12618001541291).
Publisher: Elsevier BV
Date: 05-2020
Publisher: Wiley
Date: 14-10-2020
DOI: 10.1002/JHA2.116
Publisher: Wiley
Date: 2021
DOI: 10.1002/CTI2.1351
Abstract: A erse intratumoral T‐cell receptor (TCR) repertoire is associated with improved survival in diffuse large B‐cell lymphoma (DLBCL) treated with rituximab/cyclophosphamide/doxorubicin rednisolone/vincristine (R‐CHOP) chemoimmunotherapy. We explored the impact of intratumoral TCR repertoire on interim PET (iPET) done after four cycles of R‐CHOP, the relationships between intratumoral and circulating repertoire, and the phenotypes of expanded clonotypes. We sequenced the third complementarity‐determining region of TCRβ in tumor s les, blood at pre‐therapy and after four cycles of R‐CHOP in 35 patients enrolled in ALLGNHL21 trial in high‐risk DLBCL. We correlated the TCR ersity metrics with iPET status, gene expression profiles and HLA‐class I genotypes. We then sequenced the FACS‐sorted peripheral blood T cells in six patients, and pentamer‐sorted EBV‐specific CD8 + T cells in one patient from this cohort. Compared with iPET − patients, the intratumoral TCR repertoire in iPET + patients was characterised by higher cumulative frequency of abundant clonotypes and higher productive clonality. There was a variable overlap between circulating and intratumoral repertoires, with the dominant intratumoral clonotypes more likely to be detected in the blood. The majority of shared clonotypes were CD8 + PD‐1 HI T cells, and CD8 + T cells had the largest clonal expansions in tumor and blood. In a patient with EBV + DLBCL, EBV‐specific intratumoral clonotypes were trackable in the blood. This study demonstrates that clonally expanded intratumoral TCR repertoires are associated with iPET + and that the blood can be used to track tumor‐associated antigen‐specific clonotypes. These findings assist the rationale design and therapeutic monitoring of immunotherapeutic strategies in DLBCL.
Publisher: Wiley
Date: 10-02-2019
DOI: 10.1111/BJH.15778
Publisher: American Society of Hematology
Date: 27-03-2014
DOI: 10.1182/BLOOD-2013-10-535443
Abstract: Programmed death ligands 1 and 2 are rearranged at a frequency of 20% in PMBCL.
Location: Australia
No related grants have been discovered for Jay Gunawardana.