PubMed Health⌕ Search

Biomedical subjects

Brian Orr

Publications and source records attributed to Brian Orr.

4 recordsLinked to original sources
PubMed2025

The protective role of γδ T cells in endometrial cancer.

Γδ T cells are non-conventional T cells that are not MHC restricted and have T cell receptors (TCRs) that are stimulated by phosphoantigens, stress-induced proteins, lipids, and other antigens. These cells are prognostic across cancer types in The Cancer Genome Atlas (TCGA) but have not been well studied in endometrial cancer, which has a rising incidence and mortality rate. Endometrial cancer patients have variable responses to checkpoint inhibitors which are related to the molecular subtype of their cancer. As such, there is a pressing need to understand the immune microenvironment in endometrial cancer. This study addresses this gap in knowledge by investigating γδ T cell repertoires and transcriptomes in this disease site. γδ T cell repertoires were obtained for 543 endometrial cancer patients within the TCGA and from 5 endometrial cancer patients in the single cell dataset SRP349751 using TRUST4. GLIPH2 was used to identify TCRs predicted to bind the same antigen. Transcriptomes were investigated in the single cell dataset. DNA Polymerase Epsilon Exonuclease (POLE) and Microsatellite Instability High (MSI-H) endometrial cancer subtypes had the most γδ T cell infiltration. Vδ1 and Vδ3 γδ T cell infiltration was prognostic independent of stage and molecular subtype. GLIPH2 analysis revealed TCRδ motifs for TDK, YTD, and GEL were public across all four molecular subtypes and were present in the single cell data set. Vδ1 γδ T cell transcriptomes were associated with cytotoxicity and recent TCR stimulation. These data support further investigation of immunotherapies targeting γδ T cells in endometrial cancer.

Humans↗
PubMed2006

Isolation and structural modification of 7-deoxynarciclasine and 7-deoxy-trans-dihydronarciclasine.

As an extension of structure-activity relationship studies of pancratistatin (1), various techniques were first evaluated for separating the mixtures of 7-deoxynarciclasine (2b) and 7-deoxy-trans-dihydronarciclasine (3a) isolated from Hymenocallis littoralis. An efficient solution for that otherwise difficult separation then allowed the lactam carbonyl group of protected (4c and 5c) alcohols 2b and 3a to be reduced employing lithium aluminum hydride. Cleavage (TBAF followed by H2SO4) of the silyl ester/acetonide protected 6a gave amine 8. X-ray crystal structure determinations were employed to confirm the structures of 3,4-acetonide-5-aza-6-deoxynarciclasine (6b), 5-aza-6-deoxynarciclasine (8a), and 5-aza-6-deoxy-trans-dihydronarciclasine (9a, 9b). Against the murine P388 lymphocytic leukemia and a panel of human cancer cell lines, the parent natural products, 7-deoxynarciclasine (2b) and 7-deoxy-trans-dihydronarciclasine (3a), were found to generally be more cancer cell growth inhibitory (GI50 0.1 to <0.01 microg/mL) than the compounds with structural modifications such as amine 8 by a factor of 10 or more. The trans ring juncture of isocarbostyril 3a proved to be an important modification of narciclasine (2a) for improving cancer cell growth inhibition in this series.

Amaryllidaceae Alkaloids↗
PubMed2003

Defining the new normal.

Throughout the extended SARS outbreak, healthcare organizations across Ontario operated under directives that imposed significant changes to patient and operational practices. The outbreak dramatically illustrated the critical need to transform healthcare organizations to a "new normal" state of operation to respond to the ease by which contagious diseases can spread globally.

Cooperative Behavior↗