journal contribution
posted on 2023-12-01, 07:23 authored by Sotiria Pinioti, Himal Sharma, Nina C. Flerin, Qian Yu, Amalia Tzoumpa, Sarah Trusso Cafarello, Elien De Bousser, Nico Callewaert, Guillaume Oldenhove, Susan Schlenner, Bernard Thienpont, Abhishek D. Garg, Mario Di Matteo, Massimiliano Mazzone Gating strategy and quality controls of the CRISPR/Cas9 screen. Related to Figure 1. (A) Sorting strategy of the screening. (B) Sorted populations 1, 2, 3 and 4 were analyzed by NGS and the pooled populations 1+2 = Foxp3high and 3+4 = Foxp3low were analyzed bioinformatically. The screening was repeated twice and the data represent the pool of the data from the 2 replicates. QCs for each sample from the first replication (NGS1) and from the second replication (NGS2). (C) Number of reads per sample for both repetitions of the screening mentioned as NGS1 and NGS. (D) Log10 of missed gRNAs per sample for both repetitions of the screening mentioned as NGS1 and NGS. (E) Gini index for each sample measuring inequality between read counts. (F) Distribution of normalized read counts for each sample.
Funding
HORIZON EUROPE Marie Sklodowska-Curie Actions (MSCA)
HORIZON EUROPE European Research Council (ERC)
Stichting Tegen Kanker (Fondation Contre le Cancer)
Vlaams Instituut voor Biotechnologie (VIB)
Fonds Wetenschappelijk Onderzoek (FWO)
KU Leuven (Katholieke Universiteit Leuven)
Kom op tegen Kanker (Fight Cancer)
VLIRUOS (VLIR-UOS)
History
ARTICLE ABSTRACT
Forkhead box P3 (Foxp3)–expressing regulatory T cells (Treg) are the guardians of controlled immune reactions and prevent the development of autoimmune diseases. However, in the tumor context, their increased number suppresses antitumor immune responses, indicating the importance of understanding the mechanisms behind their function and stability. Metabolic reprogramming can affect Foxp3 regulation and, therefore, Treg suppressive function and fitness. Here, we performed a metabolic CRISPR/Cas9 screen and pinpointed novel candidate positive and negative metabolic regulators of Foxp3. Among the positive regulators, we revealed that targeting the GDP-fucose transporter Slc35c1, and more broadly fucosylation (Fuco), in Tregs compromises their proliferation and suppressive function both in vitro and in vivo, leading to alteration of the tumor microenvironment and impaired tumor progression and protumoral immune responses. Pharmacologic inhibition of Fuco dampened tumor immunosuppression mostly by targeting Tregs, thus resulting in reduced tumor growth. In order to substantiate these findings in humans, tumoral Tregs from patients with colorectal cancer were clustered on the basis of the expression of Fuco-related genes. FucoLOW Tregs were found to exhibit a more immunogenic profile compared with FucoHIGH Tregs. Furthermore, an enrichment of a FucoLOW signature, mainly derived from Tregs, correlated with better prognosis and response to immune checkpoint blockade in melanoma patients. In conclusion, Slc35c1-dependent Fuco is able to regulate the suppressive function of Tregs, and measuring its expression in Tregs might pave the way towards a useful biomarker model for patients with cancer.See related Spotlight by Silveria and DuPage, p. 1570
