The mechanism of tumor-selective replication of oncolytic measles virus (MV) is poorly understood. Using a stepwise model of cellular transformation, in which oncogenic hits were additively expressed in human bone marrow-derived mesenchymal stromal cells, we show that MV-induced oncolysis increased progressively with transformation. The type 1 interferon (IFN) response to MV infection was significantly reduced and delayed, in accordance with the level of transformation. Consistently, we observed delayed and reduced signal transducer and activator of transcription (STAT1) phosphorylation in the fully transformed cells. Pre-treatment with IFNβ restored resistance to MV-mediated oncolysis. Gene expression profiling to identify the genetic correlates of susceptibility to MV oncolysis revealed a dampened basal level of immune-related genes in the fully transformed cells compared to their normal counterparts. IFN-induced transmembrane protein 1 (IFITM1) was the foremost basally downregulated immune gene. Stable IFITM1 overexpression in MV-susceptible cells resulted in a 50% increase in cell viability and a significant reduction in viral replication at 24 h after MV infection. Overall, our data indicate that the basal reduction in functions of the type 1 IFN pathway is a major contributor to the oncolytic selectivity of MV. In particular, we have identified IFITM1 as a restriction factor for oncolytic MV, acting at early stages of infection. The mechanism of tumor-selective replication of oncolytic measles virus (MV) is poorly understood. Using a stepwise model of cellular transformation, in which oncogenic hits were additively expressed in human bone marrow-derived mesenchymal stromal cells, we show that MV-induced oncolysis increased progressively with transformation. The type 1 interferon (IFN) response to MV infection was significantly reduced and delayed, in accordance with the level of transformation. Consistently, we observed delayed and reduced signal transducer and activator of transcription (STAT1) phosphorylation in the fully transformed cells. Pre-treatment with IFNβ restored resistance to MV-mediated oncolysis. Gene expression profiling to identify the genetic correlates of susceptibility to MV oncolysis revealed a dampened basal level of immune-related genes in the fully transformed cells compared to their normal counterparts. IFN-induced transmembrane protein 1 (IFITM1) was the foremost basally downregulated immune gene. Stable IFITM1 overexpression in MV-susceptible cells resulted in a 50% increase in cell viability and a significant reduction in viral replication at 24 h after MV infection. Overall, our data indicate that the basal reduction in functions of the type 1 IFN pathway is a major contributor to the oncolytic selectivity of MV. In particular, we have identified IFITM1 as a restriction factor for oncolytic MV, acting at early stages of infection.
Adult acute lymphoblastic leukaemia (ALL) is an aggressive haematological malignancy with a poor outcome for 50% of patients. CD20 is an important target antigen in ALL. I have examined the role of CD20 as a biomarker in ALL and investigated whether an oncolytic measles virus (MV) targeted to CD20 is therapeutically relevant. In Chapter 3, I analysed CD20 expression in primary specimens from the UKALL14 trial. Increasing CD20 expression ‐ whether measured by the percentage of positive ALL cells or as CD20 antigen density ‐ conferred inferior survival. I developed a RT‐qPCR assay to quantify the gene expression of CD20 for use in specimens without stored cells. This correlated well with the flow cytometry data with a similar relationship to outcome. ALL cells are known to be sensitive to MV oncolysis. Chapter 4 of my thesis investigated the therapeutic potential of a MV genetically modified to target entry via CD20. MVHCD20 was more effective than the native MV at killing CD20 positive cells in vitro. A MV ‘blinded’ to the native MV receptors by ablation of the residues necessary for receptor‐binding also demonstrated efficacy suggesting it would have therapeutic efficacy whilst avoiding offtarget effects. In Chapter 5 I investigated the underlying mechanism of the MV oncolysis previously demonstrated. Neutrophils are effector cells in MV‐oncolysis but not by antibody dependent cellular cytotoxicity, as previously shown by my lab, so I explored their role in antibody‐mediated phagocytosis after CD20 targeted MV infection of ALL cells. I demonstrated that true phagocytosis was a rare event. However, neutrophils demonstrated an antibody‐dependent cellular process called ‘trogocytosis’. Trogocytosis did not result in target cell death, however it appeared to increase neutrophil activation, which suggests that activated neutrophils may orchestrate additional immune responses following MV oncolysis.
To compare the outcome of patients diagnosed with HIV infection and diffuse large B-cell lymphoma (DLBCL) treated with R-CHOP in the cART era with that of a HIV-negative control group.From 2003 to 2011, 305 patients (97 HIV-positive) were diagnosed with DLBCL and treated with R-CHOP. Clinical features were compared using chi-square or Fisher's exact test. Survival analysis was performed using the Kaplan-Meier method and log-rank test. Multivariate analysis was performed using the Cox regression proportional hazards model.HIV-positive patients had more B symptoms and extranodal sites of disease at diagnosis, but the proportion of patients with high-intermediate/high-risk disease according to the international prognostic index (IPI) was similar between groups. Response rate was 73%, both for patients with and without HIV infection. After a median follow-up of 48 months, 30 patients relapsed after achieving a complete remission, including four HIV-positive patients. Ninety-six patients have died (19 HIV-positive), 73 of them due to DLBCL. Three patients (one HIV-positive) died due to treatment toxicity. Patients with HIV infection had a significantly longer disease-free survival (DFS) (5-year: 94 vs. 77%; P = 0.03) and overall survival (OS) (78 and 64% for HIV-positive and HIV-negative patients, respectively; P = 0.03). These results were confirmed on multivariate analysis when controlled for other potential prognostic confounders.HIV-positive patients diagnosed with DLBCL in the cART era have an excellent outcome when treated with standard immunochemotherapy. Therefore, the choice of chemotherapy in patients with lymphoma should not be influenced by HIV status.
Evidence is mounting that area-level socioeconomic indicators are important tools for predicting health outcomes. However, few studies have examined these alongside individual-level education. This nested cohort study within the control arm of the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) assesses the association of mutually adjusted individual (education) and area-level (Index of Multiple Deprivation-IMD 2007) socioeconomic status indicators and all-cause female mortality. Participants resident in England who had completed both baseline (Wave 1) and follow up (Wave 2) questionnaires were included. Follow-up was through the Health and Social Care Information Centre with deaths censored on 31st December 2012. IMD, education and a range of covariates were explored. Cox regression models adjusted for all covariates were used. Sensitivity analysis using imputation was performed (1) including those with missing data and (2) on the entire cohort who had completed the baseline questionnaire. Of the 54,539 women resident in England who completed both Wave 1 and Wave 2 questionnaires, 4,510 had missing data. The remaining 50,029 women were included in the primary analysis. Area-level IMD was positively associated with all-cause mortality for the most deprived group compared to the least deprived (HR=1.42, CI=1.14-1.78) after adjusting for all potential confounders. Sensitivity analyses showed similar results with stronger associations in the entire cohort (HR=1.90, CI=1.68-2.16). The less educated an individual, the higher the mortality risk (test for trend p=<0.001). However, the crude effect on mortality of having no formal education compared to college/university education disappeared when adjusted for IMD rank (HR=1.08, CI=0.93-1.26). Women living in more deprived areas continue to have higher mortality even in this less deprived cohort and after adjustment for a range of potential confounders. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN22488978 .
Oncolytic virotherapeutic agents are likely to become serious contenders in cancer treatment. The vaccine strain of measles virus is an agent with an impressive range of oncolytic activity in pre-clinical trials with increasing evidence of safety and efficacy in early clinical trials. This paramyxovirus vaccine has a proven safety record and is amenable to careful genetic modification in the laboratory. Overexpression of the measles virus (MV) receptor CD46 in many tumour cells may direct the virus to preferentially enter transformed cells and there is increasing awareness of the importance of nectin-4 and signaling lymphocytic activation molecule (SLAM) in oncolysis. Successful attempts to retarget MV by inserting genes for tumour-specific ligands to antigens such as carcinoembryonic antigen (CEA), CD20, CD38, and by engineering the virus to express synthetic microRNA targeting sequences, and “blinding” the virus to the natural viral receptors are exciting measures to increase viral specificity and enhance the oncolytic effect. Sodium iodine symporter (NIS) can also be expressed by MV, which enables in vivo tracking of MV infection. Radiovirotherapy using MV-NIS, chemo-virotherapy to convert prodrugs to their toxic metabolites, and immune-virotherapy including incorporating antibodies against immune checkpoint inhibitors can also increase the oncolytic potential. Anti-viral host immune responses are a recognized barrier to the success of MV, and approaches such as transporting MV to the tumour sites by carrier cells, are showing promise. MV Clinical trials are producing encouraging preliminary results in ovarian cancer, myeloma and cutaneous non-Hodgkin lymphoma, and the outcome of currently open trials in glioblastoma multiforme, mesothelioma and squamous cell carcinoma are eagerly anticipated.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)