During her cum laude PhD and postdoctoral years Sandra J. van Vliet studied the impact of glycosylation and glycan-binding receptors on dendritic cell biology and specialized in the field of glyco-immunology. She obtained a prestigious NWO-VENI grant in 2010 that allowed her to dissect the signaling properties of glycan-binding receptors. With grants from the Dutch Cancer Society, Cancer Center Amsterdam and European Marie Curie ITN network she has established her own independent research group that aims to unravel how tumor glycans affect tumor progression, metastasis and anti-tumor immunity. In 2017, Sandra van Vliet was awarded the female career award ASPASIA from the Netherlands Organisation for Scientific Research (NWO). With the ASPASIA she established the VUmc Women in Science Fund, which aims to accelerate the careers of young female scientists by providing grants for international work visits and networking.

Research Line

How does aberrant tumor cell glycosylation affect tumor cell biology?

Cellular glycosylation is a highly dynamic process that alters upon activation, inflammation, and oncogenic transformation. Although it has been known for decades that cell surface glycans are highly diverse, it is still unclear how glycan heterogeneity is established and how this impacts tumor cell biology and tumor-immune cell recognition. We employ CRISPR/Cas9 genome engineering (both gene knockout as well as gene induction strategies) to generate isogenic tumor glycovariant cell lines. We assess the effect of tumor cell glycosylation on 3D tumor growth, as well as tumor cell differentiation, angiogenesis and drug resistance. Our new preliminary data (amongst others from RNAseq) points to an important role for cancer glycosylation in shaping tumor cell metabolism, epithelial-to-mesenchymal transition (EMT) and cancer stemness and this entails our future focus.

How does the tumor-associated glycome affect anti-tumor immunity?

Within the immune system, glycan blue prints are decoded by specific glycan-receptors, such as the C-type lectin (CLRs) or the Siglec receptors. These glycan-binding receptors are crucial in regulating the balance between immunity and tolerance and several CLRs and Siglecs seem to endow a tolerogenic phenotype on antigen presenting cells (APCs) to dampen potential immune responses directed against the tumor. We study this by correlating lectin binding to disease progression and immune cell infiltration and activation in human tumor samples.
To assess the immunological consequences of altered tumor glycosylation on a molecular level, we stimulate lectin receptors on dendritic cells and macrophages with synthetic glycoconjugates and glycan-modified dendrimers. These glycan-conditioned APC are subsequently profiled by RNAseq and characterized for their maturation marker expression, cytokine secretion and their ability to instruct effector and regulatory T cell responses. We are currently addressing whether targeting of lectin receptors also alters the metabolism of antigen presenting cells.

Figure: Staining of colorectal cancer tissue with a Fc-chimeric protein of the human C-type lectin MGL.

Key publications

  1. Cornelissen LAM, Blanas A, van der Horst JC, Kruijssen L, Zaal A, O’Toole T, Wiercx L, van Kooyk Y, van Vliet SJ. Disruption of sialic acid metabolism drives tumor growth by augmenting CD8(+) T cell apoptosis. Int J Cancer. 144(9):2290-2302 (2019)
  2. Marcelo F, Supekar N, Corzana F, van der Horst JC, Vuist IM, Live D, Boons GPH, Smith DF, van Vliet SJ. Identification of a secondary binding site in human macrophage galactose-type lectin by microarray studies: Implications for the molecular recognition of its ligands. J Biol Chem. 294(4):1300-1311 (2019).
  3. Blanas A, Cornelissen LAM, Kotsias M, van der Horst JC, van de Vrugt HJ, Kalay H, Spencer DIR, Kozak RP, van Vliet SJ. Transcriptional activation of fucosyltransferase (FUT) genes using the CRISPR-dCas9-VPR technology reveals potent N-glycome alterations in colorectal cancer cells. Glycobiology. 29(2):137-150 (2019)
  4. Blanas A, Sahasrabudhe NM, Rodríguez E, van Kooyk Y and van Vliet SJ. Fucosylated antigens in cancer: an alliance towards tumor progression, metastasis and resistance to chemotherapy. Front Oncol. 8:39 (2018)
    This article was selected for a special edition for World Cancer day 2019, highlighting a selection of top articles published in Frontiers in Oncology over the prior 12 months.
  5. Lenos K, Goos JACM, Vuist IM, den Uil SH, Delis-van Diemen PM, Belt EJTh, Stockmann HBAC, Bril H, de Wit M, Carvalho B, Giblett S, Pritchard CA, Meijer GA, van Kooyk Y, Fijneman RJA, van Vliet SJ. MGL ligand expression is correlated to BRAF mutation and associated with poor survival of stage III colon cancer patients Oncotarget 6(28):26278-90 (2015) ‒ IF 5.2, corresponding author

Group members

Irene Avila van der Haar

Irene van der Haar Àvila, MSc

The focus of my PhD project is to evaluate the impact of sialylation on the anti-tumor response in colorectal cancer (CRC) by generating CRISPR/Cas9-based CRC cell lines with different levels of sialic acids. We aim to identify specific sialo-signatures that help in predicting response and success of cancer immunotherapy. For this, we make use of in vivo tumor models, multicolor (spectral) flow cytometry, microscopy imaging, IHC, co-culture assays, and RNA sequencing data.

Laraib Amir Ali

Laraib Amir Ali

Research technician
My project explores impact of tumor sialylation in tumor immunity. For this purpose we are generating sialo variant tumor cells lines of colorectal cancer (CRC) with distinct levels of sialic acid on their surface. We will also validate these results in metastatic tumor samples of CRC patients. Finally, we will employ long peptide vaccination strategies and immune checkpoint inhibition with anti PD-L1 to evaluate whether our different sialo variant tumors react differently to these immune stimulating treatment regimens.

Nadia van der Meijs

Nadia van der Meijs, MSc

PhD student
I’m investigating the signaling of the C-type lectin receptor MGL in dendritic cells in more detail by looking at, for example, the cytokine production, co-stimulatory and inhibitory receptor expression and gene expression patterns. With different MGL ligands, that induce a different conformation in MGL after binding, we hope to steer the immune response started by the dendritic cells in different directions.

Other PI's