Genome-wide CRISPR screen identifies LGALS2 as an oxidative stress-responsive gene with an inhibitory function on colon tumor growth

Abstract

Colorectal cancer is the third leading cause of cancer-related deaths in the United States and the third most common cancer in men and women. Around 20% colon cancer cases are closely linked with colitis. Both environmental and genetic factors are thought to contribute to colon inflammation and tumor development. However, the genetic factors regulating colitis and colon tumorigenesis remain elusive. Since reactive oxygen species (ROS) is vitally involved in tissue inflammation and tumorigenesis, here we employed a genome-wide CRISPR knockout screening approach to systemically identify the genetic factors involved in the regulation of oxidative stress. Next generation sequencing (NGS) showed that over 600 gRNAs including the ones targeting LGALS2 were highly enriched in cells survived after sublethal H2O2 challenge. LGALS2 encodes the glycan-binding protein Galectin 2 (Gal2), which is predominantly expressed in the gastrointestinal tract and downregulated in human colon tumors. To examine the role of Gal2 in colitis, we employed the dextran sodium sulfate (DSS)-induced acute colitis model in mice with (WT) or without Lgals2 (Gal2-KO) and showed that Gal2 deficiency ameliorated DSS-induced colitis. We further demonstrated that Gal2-KO mice developed significantly larger tumors than WT mice using Azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colorectal cancer model. We found that STAT3 phosphorylation was significantly increased in Gal2-deficient tumors as compared to those in WT mice. Gal2 overexpression decreased the proliferation of human colon tumor epithelial cells and blunted H2O2-induced STAT3 phosphorylation. Overall, our results demonstrate that Gal2 plays a suppressive role in colon tumor growth and highlights the therapeutic potential of Gal2 in colon cancer.

In vivo multidimensional CRISPR screens identify Lgals2 as an immunotherapy target in triple-negative breast cancer

“…In two rounds of screens, Lgals2 was consistently correlated with immune escape and ranked top in the list of immune escape under all selection pressure. Lgals2 is a member of the galectin family and has a distinct expression in different tissues (34)(35)(36). It plays different roles in inflammation, immune response, and arteriogenesis, but its function in cancer has been only scarcely studied (13)(14)(15)(16).…”

Identification of Signaling Pathways for Early Embryonic Lethality and Developmental Retardation in Sephs1−/− Mice

“…Interestingly, the up-regulated genes showed region-specificity; Fgg, Afp, Trf, and Serpinf2 in the extraembryonic region and Spp2 in the placenta. Notably, Galectin 2 (Lgals2), the most up-regulated DEG, is reported to be an oxidative stress-responsive gene shown to be up-regulated under H 2 O 2 treatment [28]. These results suggest that SEPHS1-deficiency causes developmental retardation and the induction of oxidative stress.…”

Microenvironmental Reactive Oxygen Species in Colorectal Cancer: Involved Processes and Therapeutic Opportunities

“…As for CRISPR technology, genome-wide CRISPR screens have served for the identification of oxidative stress-responsive genes in CRC such as Galectin-2 (Gal2) which has a tumor-suppressive role in this cancer [161]. Moreover, House et al engineered dCas9-Killer Red to generate oxidative stress at the desired genomic region that could be used to model more natural DNA damage [162].…”