Precision cut tumor slices as an ex vivo model to assess myeloid biology and function in the tumor microenvironment

Abstract

Precision cut tumor slices (PCTS) are used as an ex vivo tissue model to study the tumor microenvironment (TME), immune interactions and treatment-induced effects.They allow researchers to analyze individual patient responses to therapies, making them valuable for personalized medicine. In this study, PCTS generated from five biopsy samples collected from patients with head and neck cancer or esophageal cancer. After tissue slicing using a vibratome, the slices were treated with either lipopolysaccharide (LPS) as a positive control, the bispecific therapeutic antibodies ATOR-4066 and 4224, or left untreated. Flow cytometry was used to evaluate changes in immune cell populations and activation in response to these treatments. The study investigated the impact of slicing on cell viability, while also characterizing specific immune cell populations including CD4+-and CD8+ T cells, B cells and myeloid antigen presenting cells (APCs). Additionally, the tumor antigens CEACAM5 and EpCAM were analysed, along with immune activation markers CD86, PD-L1, CD69 and PD-1 to identify potential increase in activation and regulatory activity of the immune cells post treatment. Results showed a reduction of CD4+ T cells and myeloid APCs following slicing, suggesting a sensitivity to mechanical stress. No other consistent association between specific cell subset and slicing was observed. The expression levels of CEACAM5 and EpCAM were fairly low in all patient samples, implying a limited potential efficacy of the therapeutic agents ATOR-4066 and 4224. However, in two of the patient samples an increased expression of the PD-L1 marker indicated activation of B cells and myeloid APCs.

Popular Abstract

Tumor Slicing Technology -Opening Doors To PersonalizedCancer Therapies

Over the past decades, immunotherapy has had groundbreaking advancements in cancer treatment, leading to new therapies for otherwise historically poor-prognosis cancer diseases. A crucial factor for future development is to mimic the natural tumor environment to the greatest extent where a new powerful tool called precision cut tumor slice (PCTS) offers a huge potential. This innovative method allows for thin slicing of tumor tissue while keeping the tumor structure and cell arrangement intact, which gives a better understanding of cell behaviour. The tumor environment mainly consists of cancer cells, immune cells and signalling substances enabling the communication between the cells. Immune cells are the body's defense system for fighting off harmful threats, such as viruses or cancer. The most common immune cells are; T helper cells (CD4+) which aid almost all other immune cells, cytotoxic T cells ( CD8+) whom by themselves can kill cancer cells, myeloid antigen presenting cells (myeloid APCs), (including DCs, macrophages and neutrophils) which is a group of immune cells that help other immune cells recognise invaders, and B cells who both identifies invaders and produce antibodies that help mark the invaders for destruction. The tumor environment plays a critical role in tumor development and depending on what cells are present around the tumor, the prognosis and effect of treatment can vary. Therefore, the need for new methods that better mimic or help uphold this environment are crucial for the advancement of immunotherapies. Today, there are several 2D models available to test anti-cancer drugs by mimicking the tumor organization. These models help to get a better idea of how the drug might work inside the body. However, they lack the tumor microenvironment including the signalling pathways and relationships between different cell types. This can limit how well the potential drug actually performs when inside the body. Unlike the methods mimicking the tumor environment, PCTS is a 3D method that successfully preserves it. PCTS utilizes a machine, vibratome, where the tumor tissue is cut into thin slices by a vibrating blade cutting in a saw-like movement. During slicing, the cells are exposed to both mechanical disruption that could cause physical damage and dangerous molecules that are built up from the slicing. These two stress factors can hurt the cells and either make them act abnormally or, in the worst case, kill them. In this study, tumor tissue was cut using a vibratome and thereafter either remained untreated or treated with immune-stimulating drugs and a positive control. The study showed that cutting tumor tissue into thin slices reduces the number of live cells, mostly killing non-immune cells. Among the immune cells, T helper cells and myeloid APCs are the two immune populations that are particularly sensitive to slicing, or more specifically to the two stress factors that slicing entails. Further, two immune-boosting antibody drugs, ATOR-4066 and 4224, were tested and showed minimal effect mostly because the target they act on was only present in low amounts. Still, there were some indications that one of the drugs (4224) could activate some immune cells, B cells and myeloid APCs, in some patient samples. Even though further research is needed to validate these findings and verify the effectiveness of the immune-boosting drugs, this study highlights the importance of understanding the tumor environment and cell communications to further develop cancer treatments and, once and for all, cure all cancers.

• author: Honnér, Tindra and Nydemark, Julia
• supervisor: Malin Lindstedt; Hampus Andersson
• organization: Department of Immunotechnology
• course: KIMM05 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences
• keywords: Immunology, Ex vivo models, cancer, antibodies
• language: English
• id: 9195041
• date added to LUP: 2025-06-10 08:42:30
• date last changed: 2025-06-11 19:02:07