human genome-wide crispra-v2 libraries #83978  (Addgene inc)

Journal: bioRxiv

Article Title: CRISPR activation screens map the genomic landscape of cancer glycome remodeling

doi: 10.1101/2025.05.26.656133

Figure Lengend Snippet: A) Inhibition of anticancer immunity by Siglec receptors. Siglecs bind to sialic acid-containing glycans on the surface of target cells. B) Components of the Siglec-7 ligand structure. Disialyl-T glycans are organized in dense arrays on the backbone of specific mucin-type O-glycoproteins. C ) Targeted overexpression of genes by CRISPRa. A cell line expressing a dCas9-GCN4 peptide array and a VP64-SunTag fusion protein serves as the target cell line (K-562-CRISPRa cells). This cell line is lentivirally transduced with an sgRNA targeting the promoter region of a target gene. Subsequent recruitment of chromatin remodeling factors induces an increase in transcriptional activity. D) Recombinant Siglec-Fc proteins were precomplexed with an AlexaFluor647-antihuFc antibody (1 μg/mL) for 1 hour on ice. Precomplexes were subsequently incubated with K-562 cells for 30 minutes and analyzed by flow cytometry. Representative flow cytometry plots are depicted for each Siglec-Fc as well as a human Fc (hFc) negative control. E) K-562-CRISPRa cells were lentivirally transduced with a genome-wide library of ∼104,000 sgRNAs (5 sgRNAs/gene). After selection and propagation, 1.25 x 10 8 cells were then stained with Siglec-Fc reagents as in B . A high-binding (top 20%) and low-binding (bottom 20%) of the fluorescent population was then selected and sorted by FACS.

Article Snippet: The CRISPRa-v2 library (top 5 sgRNAs/gene) containing 104,535 sgRNAs was purchased from Addgene (Pooled Library 83978).

Techniques: Inhibition, Over Expression, Expressing, Peptide Microarray, Transduction, Activity Assay, Recombinant, Incubation, Flow Cytometry, Negative Control, Genome Wide, Selection, Staining, Binding Assay

Journal: bioRxiv

Article Title: CRISPR activation screens map the genomic landscape of cancer glycome remodeling

doi: 10.1101/2025.05.26.656133

Figure Lengend Snippet: A) K-562-dCas9-CRISPRa cells were transduced with two different sgRNAs targeting the CD24 promoter region. After selection with puromycin, cells were stained with Siglec-10-Fc as in 1B and with a fluorescent antibody against CD24. Representative flow cytometry plots for both stains are shown. B) THP-1 cells were stained with Siglec-10-Fc as in 1B and a fluorescent antibody against CD24. Representative flow cytometry plots for both stains are shown. C) OCI-AML-2-Cas9 cells were lentivirally transduced with an sgRNA targeting MGAT1 to generate a polyclonal cell population containing WT and MGAT1 KO cells. Cells were then co-stained with Siglec-10-Fc and the lectin L-PHA (5 μg/mL), which binds to complex N-linked glycans. Representative staining is indicated on the flow cytometry plot. D) Graph indicates MFI of Siglec-10-Fc staining in the WT (L-PHA+) and MGAT1 KO (L-PHA-) populations. E) OCI-AML-2-Cas9 cells were lentivirally transduced with an sgRNA targeting C1GALT1. Cells were co-stained with Siglec-10-Fc and the lectin DBA, which binds to exposed α-GalNAc. Representative staining is indicated on the flow cytometry plot. F) Graph indicates MFI of Siglec-10-Fc staining in the WT (DBA-) and C1GALT1 KO (DBA+) populations. G) Pathway diagram indicates the enzymes involved in 2,3-linked and 2,6-linked sialylation of N-linked glycans. ST3GAL4, ST3GAL6 and ST6GAL1 were all strong hits in the Siglec-10 screen. H) The heat map indicates the average mRNA expression of key glycosyltransferase hits in cell lines derived from B-ALL, T-ALL, AML and multiple myeloma. mRNA expression values were extracted from DepMap and the Human Protein Atlas. I) OCI-AML-2-Cas9 cells were transduced an sgRNAs against ST3GAL4. Cells were then stained with fluorescently labeled Siglec-10-Fc. A representative flow cytometry plot is shown. J) The MFI of Siglec-10 staining in OCI-AML-2 WT and ST3GAL4 KO cells is indicated. MFI is internally normalized to the WT cell line. K) MM1S-Cas9 cells were transduced an sgRNAs against ST6GAL1. ST6GAL1 KO cells were isolated by FACS using the lectin SNA. Cells were then stained with fluorescently labeled Siglec-10-Fc. A representative flow cytometry plot is shown. L) The MFI of Siglec-10 staining in MM1S WT and ST6GAL1 KO cells is indicated. MFI is internally normalized to the WT cell line. M) K-562-CRISPRa cells were transduced and stained as in 4C . A representative flow cytometry plot is shown comparing Siglec-10-Fc staining in cells transduced with a non-targeting (NT) sgRNA to cells within the “CD44 High” expression gate. N) The MFI of Siglec-10-Fc staining in NT cells vs. “CD44 High” cells is shown. MFI is internally normalized to the WT cell line. O) K-562 CRISPRa cells were transduced with an sgRNA against CSPG4 and co-stained with Sig10-Fc and a CSPG4 antibody as in 4C . A representative flow cytometry plot is shown comparing Siglec-10-Fc staining in cells transduced with a non-targeting (NT) sgRNA to cells within the “CSPG4 High” expression gate. P) The MFI of Siglec-10 staining in NT cells vs. “CSPG4 High” cells is shown. MFI is internally normalized to the WT cell line. Statistical significance was determined using a two-tailed t-test. ** indicates p<0.01, * indicates p<0.05. Mean values plotted, error bars indicate SEM.

Article Snippet: The CRISPRa-v2 library (top 5 sgRNAs/gene) containing 104,535 sgRNAs was purchased from Addgene (Pooled Library 83978).

Techniques: Transduction, Selection, Staining, Flow Cytometry, Expressing, Derivative Assay, Labeling, Isolation, Two Tailed Test