Remove the "sugar-coated" CAR-T from tumor cells and become a "cannonball"!

By activating T cells through genetic engineering technology and installing a device that locates and navigates to the tumor-tumor chimeric antigen receptor (CAR), the ordinary "weapon" of T cells can be transformed into a "super weapon", namely for CAR-T cells
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CAR-T is an effective therapy for B-cell malignancies, but has limited efficacy in solid tumors

Glycosylation is one of the most common protein modifications, and the products come in the form of glycoproteins
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Glycoproteins are formed by covalently linking glycans to asparagine or serine or threonine residues of proteins

On January 19, 2022, researchers from Italy found that the abundance of extracellular N-glycan expression in various tumors was negatively correlated with the degree of CAR-T cell killing
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By knocking out MGAT5 in pancreatic cancer (PAC), they found that N-glycans interfere with immune synapse formation, reduce transcriptional activation, cytokines, and cytotoxicity, and protect tumors from CAR-T cell killing

Research results (Image source: STM)

To uncover the biological role of N-glycans in pancreatic cancer, the researchers first used a bioinformatics database to analyze mutations in the glycosyltransferases involved in the synthesis of these glycosyl groups and found that 19% of cBioportal's 3,738 patients The samples carried genomic alterations in glycosyltransferases involved in N-glycan synthesis, and this feature was associated with poor prognosis
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Further analysis determined that only genetic variants of branched N-glycan synthesis were significantly associated with worse disease-free survival, and that most of the variants were gene amplifications

Gene variants associated with N-glycan synthesis and prognosis in patients with pancreatic cancer (Source: STM)

After knocking out MGAT5, it was found that the anti-tumor effect of CAR-T cells 44v6.
28 was significantly enhanced, which was manifested by increased tumor cell lysis activity and increased levels of interferon and tumor necrosis factor
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These results suggest that branched N-glycans shield the targeting of CAR-T to pancreatic cancer antigen 44v6.

Changes in tumor cells and CAR-T cells after knocking out MGAT5 (Source: STM)

To explore the basis for the enhanced antitumor efficacy of N-glycan-deficient tumor cells, the researchers analyzed the formation of immune synaptic IS, a limiting step in the targeting process of CAR-T cells
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The results showed that pancreatic cancer cells lacking the MGAT5 glycan product formed a good IS with CAR-T44v6.

Immune synapse and functional cell lysis after MGAT5 knockout (Image source: STM)

Since the inhibition of N-glycans at the genetic level has shown good results, could pharmacological overcoming of tumor glycosylation achieve similar results? The researchers cleverly used the glucose/mannose analog 2DG to achieve this intervention
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2DG has previously been reported to interfere with N-chain glycosylation, merging into oligosaccharides of nascent glycoproteins, resulting in an overall abnormal state of glycosylation

The effect of pancreatic cancer on the sensitivity of 44v6.
28 cells after 2DG treatment (Image source: STM)

We compared long-term combination therapy with 2DG and 44v6.
28 cells alone and in combination in a high tumor burden pancreatic cancer xenograft mouse model
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In the T3M-4 xenograft model, repeated injections of 2DG alone were shown to be ineffective in mice, while the combination of 2DG and 44v6.

Comparison of 2DG treatment and 44v6.
28 cell treatment in pancreatic cancer model (Source: STM)

In conclusion, the combination of CAR-T cells with 2DG showed good potential in the treatment of pancreatic cancer, and also achieved good results in the treatment of various other tumors, including tumors from the lung, ovary, and bladder
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Overall, this study found that extracellular N-glycans make tumors resistant to therapy by increasing the CAR-T cell activation threshold and promoting CAR-T cell exhaustion, and also provides new ideas for rational improvement of solid tumor treatment methods and methods.
direction
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References:

[1]Greco B, Malacarne V, De Girardi F, et al.
Disrupting N-glycan expression on tumor cells boosts chimeric antigen receptor T cell efficacy against solid malignancies.
Sci Transl Med.
2022;14(628):eabg3072.
doi: 10.
1126/scitranslmed.
abg3072.