generation-human-induced-pluripotent-stem-cell-derived-planar-hair

Generation of Human Induced Pluripotent Stem Cell-derived Planar Hair-bearing Skin Organoids Using an Air-Liquid Interface Culture System

Human induced pluripotent stem cell (hiPSC)-derived skin organoids (SOs) containing hair follicles provide a sophisticated in vitro model for ...

Leiden University Medical Center

Aberrant glycosylation is a key mechanism employed by cancer cells to evade immune surveillance, induce angiogenesis and metastasis, among other hallmarks of cancer. Sialic acids, distinctive terminal glycan structures located on glycoproteins or glycolipids, are prominently upregulated across various tumor types, including colorectal cancer (CRC). Sialylated glycans modulate anti-tumor immune responses through their interactions with Siglecs, a family of glycan-binding receptors with specificity for sialic acid-containing glycoconjugates, often resulting in immunosuppression. In this paper, we investigated the immunomodulatory function of ST3Gal5, a sialyltransferase that catalyzes the addition of α2-3 sialic acids to glycosphingolipids, since lower expression of ST3Gal5 is associated with better survival of CRC patients. We employed CRISPR/Cas9 to knock out the ST3Gal5 gene in two murine CRC cell lines MC38 and CT26. Glycomics analysis confirmed the removal of sialic acids on glycolipids, with no discernible impact on glycoprotein sialylation. Although knocking out ST3Gal5 in both cell lines did not affect in vivo tumor growth, we observed enhanced levels of regulatory T cells in CT26 tumors lacking ST3Gal5. Moreover, we demonstrate that the absence of ST3Gal5 affected size and blood vessel density only in MC38 tumors. In summary, we ascertain that sialylation of glycosphingolipids has a limited influence on the anti-tumor immune response in CRC, despite detecting alterations in the tumor microenvironment, possibly due to a shift in ganglioside abundance.

Limited impact of cancer-derived gangliosides on anti-tumor immunity in colorectal cancer.

Abnormal levels of tumor-associated glycans are correlated with tumor progression in many types of cancer, including (CRC). Sialic acids, a family of nine-carbon monosaccharides, are key regulators of the anti-tumor immune response via Siglecs, yet the sialic acid-specific effects are highly dependent on the tumor type studied. Therefore, a detailed understanding of sialic acid-mediated immunomodulation in different tumor contexts is warranted. Using CRISPR/Cas9 technology, we generated an isogenic knockout of the N-acylneuraminate cytidylyltransferase (Cmas) gene in CT26 CRC cells, thus creating cells that lack cell surface sialylation. Compared to CT26-MOCK control cells, CT26-CMAS KO cells displayed significantly reduced tumor growth in vivo, resulting in increased survival of the mice. This difference was absent in immunodeficient mice, signifying an immune-dependent effect. High-dimensional profiling of immune cell networks in the tumor microenvironment revealed increased infiltration and differentiation trajectories of lymphoid cells in the CT26-CMAS KO tumors, especially of natural killer (NK) cells and γδ T cells. Strikingly, sialic acid ablation resulted in a stronger immunostimulatory capacity and did not synergize with anti-PD-L1 checkpoint inhibition, suggesting that at least in the CT26 model, sialic acids impose a superior immune inhibitory circuit than the well-known PD-1/PD-L1 pathway. Overall, our findings strengthen the concept of sialic acid-mediated impairment of tumor immune surveillance and reinforce ongoing efforts to target sialic acids for the treatment of cancer.

Article	Year
Limited impact of cancer-derived gangliosides on anti-tumor immunity in colorectal cancer. Glycobiology\| PubMed ID: 38785323	2024
Tumor desialylation surpasses anti-PD-L1 checkpoint therapy in restoring anti-tumor immunity in a murine model for colorectal cancer. International journal of cancer\| PubMed ID: 40622037	2025

Victor Lorrain

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