The Microenvironment of Small Intestinal Neuroendocrine Tumours Contains Lymphocytes Capable of Recognition and Activation after Expansion

Abstract

Traditionally, immune evasion and immunotherapy have been studied in cancers with a high mutational load such as melanoma or lung cancer. In contrast, small intestinal neuroendocrine tumours (SINETs) present a low frequency of somatic mutations and are described as genetically stable tumours, rendering immunotherapies largely unchartered waters for SINET patients. SINETs frequently metastasise to the regional lymph nodes and liver at the time of diagnosis, and no curative treatments are currently available for patients with disseminated disease. Here, we characterised the immune landscape of SINET and demonstrated that tumour-infiltrating lymphocytes (TILs) can be expanded and activated during autologous tumour challenge. The composition of lymphocyte subsets was determined by immunophenotyping of the SINET microenvironment in one hepatic and six lymph node metastases. TILs from these metastases were successfully grown out, enabling immunophenotyping and assessment of PD-1 expression. Expansion of the TILs and exposure to autologous tumour cells in vitro resulted in increased T lymphocyte degranulation. This study provides insights into the largely unknown SINET immune landscape and reveals the anti-tumour reactivity of TILs, which might merit adoptive T cell transfer as a feasible treatment option for patients with SINET.

Druggable Growth Dependencies and Tumor Evolution Analysis in Patient-Derived Organoids of Neuroendocrine Cancer

“…IHC staining for the proliferation marker, Ki67 showed similar numbers of Ki67+ cells per field of view in NEN PDTOs and their matched parental tumors (Figure 2C and S2C). In line with these data, a comparison of the mRNA expression of MKI67 in PDTOs derived from tumors of different grades confirmed that all PDTOs presented MKI67 expression levels within what has been reported in their respective histopathological type (Alcala et al, 2019;Alvarez et al, 2018;Hofving et al, 2021) (Figure 2D).…”

Antigen Presenting Cells from Tumor and Colon of Colorectal Cancer Patients Are Distinct in Activation and Functional Status, but Comparably Responsive to Activated T Cells

“…Cell suspensions were stained, as described [37,40]. Briefly, cell viability in 1 mL cell suspension containing 1 million cells was determined by Zombie Red Fixable viability dye (Biolegend), followed by 20 min incubation with fluorescence-conjugated antibodies (Supplementary Table S2).…”

A Fraction of CD8+ T Cells from Colorectal Liver Metastases Preferentially Repopulate Autologous Patient-Derived Xenograft Tumors as Tissue-Resident Memory T Cells

“…We expanded TILs in vitro from the CRLM from two patients ( Figure 3 A–E) for subsequent transfer to lymphocyte-deficient PDX mice bearing subcutaneous tumor implants derived from the autologous CRLM, as previously described [ 23 , 27 ].…”

“…Cell suspensions were stained as previously described [ 13 , 24 , 27 ]. Briefly, cell viability was determined by Zombie Red Fixable viability dye (Biolegend, San Diego, CA, USA).…”

“…After 10–14 days, RepTILs were harvested and used for experiments. RepTILs were cultured for 6 h with or without 2 μL of MACSiBead particles, and IFN-γ staining was performed as previously described [ 24 , 27 ].…”