Remodeling of the Lymph Node High Endothelial Venules Reflects Tumor Invasiveness in Breast Cancer and is Associated with Dysregulation of Perivascular Stromal Cells

Abstract

The tumor-draining lymph nodes (TDLNs) are primary sites for induction of tumor immunity. They are also common sites of metastasis, suggesting that tumor-induced mechanisms can subvert anti-tumor immune responses and promote metastatic seeding. The high endothelial venules (HEVs) together with CCL21-expressing fibroblastic reticular cells (FRCs) are essential for lymphocyte recruitment into the LNs. We established multicolor antibody panels for evaluation of HEVs and FRCs in TDLNs from breast cancer (BC) patients. Our data show that patients with invasive BC display extensive structural and molecular remodeling of the HEVs, including vessel dilation, thinning of the endothelium and discontinuous expression of the HEV-marker PNAd. Remodeling of the HEVs was associated with dysregulation of CCL21 in perivascular FRCs and with accumulation of CCL21-saturated lymphocytes, which we link to loss of CCL21-binding heparan sulfate in FRCs. These changes were rare or absent in LNs from patients with non-invasive BC and cancer-free organ donors and were observed independent of nodal metastasis. Thus, pre-metastatic dysregulation of core stromal and vascular functions within TDLNs reflect the primary tumor invasiveness in BC. This adds to the understanding of cancer-induced perturbation of the immune response and opens for prospects of vascular and stromal changes in TDLNs as potential biomarkers.

The pre-metastatic niche in lymph nodes: formation and characteristics

“…Structural and molecular remodeling of HEVs has been more recently observed in patients with breast cancer although not in healthy patients. This remodeling was associated with the dysregulation of CCL21 in perivascular FRCs, disturbing the migration of CCR7 + naïve lymphocytes in the LN parenchyma [99].…”

High Endothelial Venules: A Vascular Perspective on Tertiary Lymphoid Structures in Cancer

“…Similar to inflamed LNs, sentinel LNs also undergo vascular remodeling (88,(134)(135)(136)(137). Sentinel LN-HEVs often show dramatic morphological changes, shifting from thick-walled blood vessels with a small lumen to a thin-walled vasculature with an enlarged lumen and abundant red blood cells (RBC).…”

“…Sentinel LN-HEVs often show dramatic morphological changes, shifting from thick-walled blood vessels with a small lumen to a thin-walled vasculature with an enlarged lumen and abundant red blood cells (RBC). Moreover, HEVs of sentinel LNs can display loss in PNAd/ MECA79 expression in association with dysregulation of CCL21 in perivascular FRCs (134)(135)(136). Given the importance of PNAd and CCL21 in the recruitment remodeling of naïve T cells and initiation of the adaptive response, the dysregulation of these components in sentinel LNs may indicate impaired LN functionality.…”

“…HEV abnormality has been observed in sentinel LNs of breast cancer, melanoma, and squamous cell cancer patients (88,(134)(135)(136)(137). As these modifications occur before detection of metastatic cancer cells in the sentinel LN (135,136), it is conceivable that tumor-emanating factors induce LN-HEV alterations to establish a pre-metastatic niche permissive for tumor cells. One could also speculate that the presence of enlarged HEV lumen engorged with RBC, could enhance oxygen and nutrient delivery for arriving cancer cells.…”

Lymph node fibroblastic reticular cells steer immune responses

“…In particular, TRCs in tumor dLNs downregulate CCL21 and IL-7 compared with TRCs from non-dLNs, thus limiting CD4 + T cell priming [ 61 ]. In tumor dLNs from invasive breast cancer patients, discontinuous HEVs with thinning of the endothelium as well as dysregulated CCL21 production from perivascular FRCs have been observed [ 62 ]. Overall, in response to tumor-derived factors, LN FRC remodeling seems to occur at the transcriptional, translational, and structural levels, contributing to a pre-premetastatic immunosuppressive niche in LNs.…”