Multiplexed immunofluorescence identifies high stromal CD68+PD‑L1+ macrophages as a predictor of improved survival in triple negative breast cancer

Triple negative breast cancer (TNBC) comprises 10–15% of all breast cancers and has a poor prognosis with a high risk of recurrence within 5 years. PD-L1 is an important biomarker for patient selection for immunotherapy but its cellular expression and co-localization within the tumour immune microenvironment and associated prognostic value is not well defined. We aimed to characterise the phenotypes of immune cells expressing PD-L1 and determine their association with overall survival (OS) and breast cancer-specific survival (BCSS). Using tissue microarrays from a retrospective cohort of TNBC patients from St George Hospital, Sydney (n = 244), multiplexed immunofluorescence (mIF) was used to assess staining for CD3, CD8, CD20, CD68, PD-1, PD-L1, FOXP3 and pan-cytokeratin on the Vectra Polaris™ platform and analysed using QuPath. Cox multivariate analyses showed high CD68+PD-L1+ stromal cell counts were associated with improved prognosis for OS (HR 0.56, 95% CI 0.33–0.95, p = 0.030) and BCSS (HR 0.47, 95% CI 0.25–0.88, p = 0.018) in the whole cohort and in patients receiving chemotherapy, improving incrementally upon the predictive value of PD-L1+ alone for BCSS. These data suggest that CD68+PD-L1+ status can provide clinically useful prognostic information to identify sub-groups of patients with good or poor prognosis and guide treatment decisions in TNBC

TILs immunophenotype in breast cancer predicts local failure and overall survival : analysis in a large radiotherapy trial with long-term follow-up

Aim: To determine the prognostic significance of the immunophenotype of tumour-infiltrating lymphocytes (TILs) within a cohort of breast cancer patients with long-term follow-up. Methods: Multiplexed immunofluorescence and automated image analysis were used to assess the expression of CD3, CD8, CD20, CD68, Fox P3, PD-1 and PD-L1 in a clinical trial of local excision and radiotherapy randomised to a cavity boost or not (n = 485, median follow-up 16 years). Kaplan–Meier and Cox multivariate analysis (MVA) methodology were used to ascertain relationships with local recurrence (LR), overall survival (OS) and disease-free survival (DFS). NanoString BC360 gene expression panel was applied to a subset of luminal patients to identify pathways associated with LR. Results: LR was predicted by low CD8 in MVA in the whole cohort (HR 2.34, CI 1.4–4.02, p = 0.002) and luminal tumours (HR 2.19, CI 1.23–3.92, p = 0.008) with associations with increased stromal components, decreased Tregs (FoxP3), inflammatory chemokines and SOX2. Poor OS was associated with low CD20 in the whole cohort (HR 1.73, CI 1.2–2.4, p = 0.002) and luminal tumours on MVA and low PD-L1 in triple-negative cancer (HR 3.44, CI 1.5–7, p = 0.003). Conclusions: Immunophenotype adds further prognostic data to help further stratify risk of LR and OS even in TILs low-luminal tumours

Overexpression of αvβ6 integrin alters the colorectal cancer cell proteome in favor of elevated proliferation and a switching in cellular adhesion that increases invasion

Many proteins enhance cancer progression toward life-threatening metastases. These include linking proteins called integrins that mediate cell adhesion to the extracellular matrix (ECM), consequently altering both function and phenotype. Specific neoexpression of the β6 integrin subunit correlates with the epithelial-to-mesenchymal transition, metastasis, and poor overall patient survival. While β6 is implicated in these processes, exactly how it affects signaling and/or proteolytic pathways in metastasis remains unclear. A membrane-enriched peptide immobilized pH gradient isoelectric focusing (IPG-IEF) shotgun proteomics study was undertaken in which subclones of the SW480 colorectal cancer cell line transfected with a vector inducing unregulated β6 integrin overexpression were compared with the “empty” mock vector control cell line. β6 overexpression induced a significant change in 708 proteins and was found to be localized across most intracellular locations, some involving cellular processes and pathways underpinning cancer progression. Proteomics data have been deposited to the ProteomeXchange with identifier PXD000230. β6 expression increased cell proliferation 4-fold while decreasing cell adhesion to many integrin ECM substrates. β6 expression also enhanced cell invasion and promoted the expression/repression of many established cancer-related pathways.14 page(s

An improved method for the detection and enrichment of low-abundant membrane and lipid raft-residing proteins

A high degree of optimisation is required in native co-immunoprecipitation (co-IP) experiments with added challenges for low-abundant membrane proteins and masking by IgG molecules. Although in vivo tagged-protein purification avoids the IgG masking problem, modifying the terminus of the protein may result in conformational and post-translational modification changes. In this paper, we propose a method which combines four key aspects to improve the solubility and enrichment of low-abundant plasma membrane proteins using the urokinase plasminogen activator receptor (uPAR) as an example. As this GPI-linked receptor predominantly resides in lipid rafts (LR), we used a modified RIPA lysis buffer containing the non-ionic detergent, octyl-glucoside which solubilizes LRs to extract uPAR. This is followed by a modified crosslinking co-IP which covalently crosslinks the antibodies to the beads. Crosslinking allowed for a significant increase in the detection of uPAR with minimal IgG contamination using on-bead digestion or acid elution followed by digestion and analysis on high-throughput one-dimensional (nanoLC) MS/MS instrument (AbSciex 5600). To the best of our knowledge, this method of isolation is the first to be done to increase the yield of a low-abundant membrane protein and may be useful for the purification of other non-raft and raft-residing membrane proteins.6 page(s

Overexpression of αvβ6 Integrin Alters the Colorectal Cancer Cell Proteome in Favor of Elevated Proliferation and a Switching in Cellular Adhesion That Increases Invasion

Many proteins enhance cancer progression toward life-threatening metastases. These include linking proteins called integrins that mediate cell adhesion to the extracellular matrix (ECM), consequently altering both function and phenotype. Specific neoexpression of the β6 integrin subunit correlates with the epithelial-to-mesenchymal transition, metastasis, and poor overall patient survival. While β6 is implicated in these processes, exactly how it affects signaling and/or proteolytic pathways in metastasis remains unclear. A membrane-enriched peptide immobilized pH gradient isoelectric focusing (IPG-IEF) shotgun proteomics study was undertaken in which subclones of the SW480 colorectal cancer cell line transfected with a vector inducing unregulated β6 integrin overexpression were compared with the “empty” mock vector control cell line. β6 overexpression induced a significant change in 708 proteins and was found to be localized across most intracellular locations, some involving cellular processes and pathways underpinning cancer progression. Proteomics data have been deposited to the ProteomeXchange with identifier PXD000230. β6 expression increased cell proliferation 4-fold while decreasing cell adhesion to many integrin ECM substrates. β6 expression also enhanced cell invasion and promoted the expression/repression of many established cancer-related pathways

Copper chelation suppresses epithelial-mesenchymal transition by inhibition of canonical and non-canonical TGF-β signaling pathways in cancer

Abstract Background Metastatic cancer cells exploit Epithelial-mesenchymal-transition (EMT) to enhance their migration, invasion, and resistance to treatments. Recent studies highlight that elevated levels of copper are implicated in cancer progression and metastasis. Clinical trials using copper chelators are associated with improved patient survival; however, the molecular mechanisms by which copper depletion inhibits tumor progression and metastasis are poorly understood. This remains a major hurdle to the clinical translation of copper chelators. Here, we propose that copper chelation inhibits metastasis by reducing TGF-β levels and EMT signaling. Given that many drugs targeting TGF-β have failed in clinical trials, partly because of severe side effects arising in patients, we hypothesized that copper chelation therapy might be a less toxic alternative to target the TGF-β/EMT axis. Results Our cytokine array and RNA-seq data suggested a link between copper homeostasis, TGF-β and EMT process. To validate this hypothesis, we performed single-cell imaging, protein assays, and in vivo studies. Here, we used the copper chelating agent TEPA to block copper trafficking. Our in vivo study showed a reduction of TGF-β levels and metastasis to the lung in the TNBC mouse model. Mechanistically, TEPA significantly downregulated canonical (TGF-β/SMAD2&3) and non-canonical (TGF-β/PI3K/AKT, TGF-β/RAS/RAF/MEK/ERK, and TGF-β/WNT/β-catenin) TGF-β signaling pathways. Additionally, EMT markers of MMP-9, MMP-14, Vimentin, β-catenin, ZEB1, and p-SMAD2 were downregulated, and EMT transcription factors of SNAI1, ZEB1, and p-SMAD2 accumulated in the cytoplasm after treatment. Conclusions Our study suggests that copper chelation therapy represents a potentially effective therapeutic approach for targeting TGF-β and inhibiting EMT in a diverse range of cancers