Characterisation of novel lung cancer cell lines for immuno-inhibitory markers

The present study investigates the expression of immune biomarkers, PD-L1 and HLA-1 on novel lung cancer cell lines (H838, H838-EGFR, A549, A549-ALK, HCC 827, NCI 1650, TWIT, Jacket). PD-L1 and HLA-1 characterisation were initially performed and analysed via flow cytometry. These results showed that the expression of PD-L1 and HLA-1 varies across the cell lines from high percent to low. The effect of IFNy on biomarkers expression was also investigated following a 48 hour incubation period. of the cell lines analysed the expression of PD-L1 increases with IFNy stimulation whilst HLA-1 remains relatively unchanged. Trypan blue assays for cell viability were performed, showing that when stimulated, cells were 100% viable whereas viability decreases upon IFNy exposure

Flow cytometric phenotyping of diverse human cancer cell lines for immunological biomarkers expression

The tumour microenvironment contains a variety of distinct factors that inhibit the immune system and can cause drug resistance. Some of these factors include the expression of cell surface markers which interact directly with immune cells. Cancer cells express programmed death ligand 1 (PD-L1) and reduce the expression of major-histocompatibility complex class I, death-receptors 4/5 and Fas, limiting immune-mediated cancer cell killing. Targeting these immune markers alone or in combination could potentially increase cancer cell death and improve drug efficacy. Utilising flow cytometric analysis on breast, prostate and colorectal cancer cell lines, we have found differential expression of these markers depending on the cancer type. These findings provide a platform for future work that will entail siRNA knockdown of PD-L1 to determine the tumour-intrinsic role of this ligand, in addition to combination therapies in 2D and 3D cell culture

The Extrinsic and Intrinsic Roles of PD-L1 and Its Receptor PD-1: Implications for Immunotherapy Treatment

Programmed death-ligand 1 (PD-L1) is an immune checkpoint inhibitor that binds to its receptor PD-1 expressed by T cells and other immune cells to regulate immune responses; ultimately preventing exacerbated activation and autoimmunity. Many tumors exploit this mechanism by overexpressing PD-L1 which often correlates with poor prognosis. Some tumors have also recently been shown to express PD-1. On tumors, PD-L1 binding to PD-1 on immune cells promotes immune evasion and tumor progression, primarily by inhibition of cytotoxic T lymphocyte effector function. PD-1/PD-L1-targeted therapy has revolutionized the cancer therapy landscape and has become the first-line treatment for some cancers, due to their ability to promote durable anti-tumor immune responses in select patients with advanced cancers. Despite this clinical success, some patients have shown to be unresponsive, hyperprogressive or develop resistance to PD-1/PD-L1-targeted therapy. The exact mechanisms for this are still unclear. This review will discuss the current status of PD-1/PD-L1-targeted therapy, oncogenic expression of PD-L1, the new and emerging tumor-intrinisic roles of PD-L1 and its receptor PD-1 and how they may contribute to tumor progression and immunotherapy responses as shown in different oncology models

MicroRNA-155 is essential for the optimal proliferation and survival of plasmablast B cells.

A fast antibody response can be critical to contain rapidly dividing pathogens. This can be achieved by the expansion of antigen-specific B cells in response to T-cell help followed by differentiation into plasmablasts. MicroRNA-155 (miR-155) is required for optimal T-cell-dependent extrafollicular responses via regulation of PU.1, although the cellular processes underlying this defect are largely unknown. Here, we show that miR-155 regulates the early expansion of B-blasts and later on the survival and proliferation of plasmablasts in a B-cell-intrinsic manner, by tracking antigen-specific B cells in vivo since the onset of antigen stimulation. In agreement, comparative analysis of the transcriptome of miR-155-sufficient and miR-155-deficient plasmablasts at the peak of the response showed that the main processes regulated by miR-155 were DNA metabolic process, DNA replication, and cell cycle. Thus, miR-155 controls the extent of the extrafollicular response by regulating the survival and proliferation of B-blasts, plasmablasts and, consequently, antibody production

Programmed death-ligand 1 expression in human cancer cell lines in two-dimensional and three-dimensional cell culture systems

Solid tumours are characterised by a three-dimensional (3D) architecture that provides specific survival advantages such as resistance to anti-cancer drugs. The expression of programmed death-ligand 1 (PD-L1) is one such survival mechanism employed by tumours to mediate immune evasion, drug resistance and tumour progression. Here we investigated whether the expression of PD-L1 by human cancer cell lines altered in a 3D cell culture setting as opposed to their two-dimensional (2D) monolayer counterparts. We utilised well-established 3D cell culturing systems that facilitate the formation of spheroids and display heterogeneous populations of cells resembling that found in the tumour microenvironment, to assess PD-L1 expression. We found that PD-L1 expression changed in human breast, prostate and colorectal cancer cell lines in 3D cell culture systems when compared to their 2D counterparts. The level of expression of PD-L1 by tumour cells in 3D cell culture is more likely to mimic that of an in vivo tumour microenvironment than 2D cell culture, and may better able the investigation of the tumour-intrinsic role of PD-L1