Abstract
In cancer, proteoglycans have been found to play roles in facilitating the actions of growth factors, and effecting
matrix invasion and remodeling. However, little is known regarding the genetic and functional importance of
glycan chains displayed by proteoglycans on dendritic cells (DCs) in cancer immunity. In lung carcinoma, among
other solid tumors, tumor-associated DCs play largely subversive/suppressive roles, promoting tumor growth and
progression. Herein, we show that targeting of DC glycan sulfation through mutation in the heparan sulfate
biosynthetic enzyme N-deacetylase/N-sulfotransferase-1 (Ndst1) in mice increased DC maturation and inhibited
trafficking of DCs to draining lymph nodes. Lymphatic-driven DC migration and chemokine (CCL21)-dependent
activation of a major signaling pathway required for DC migration (as measured by phospho-Akt) were sensitive to
Ndst1 mutation in DCs. Lewis lung carcinoma tumors in mice deficient in Ndst1 were reduced in size. Purified
CD11c+ cells from the tumors, which contain the tumor-infiltrating DC population, showed a similar phenotype in
mutant cells. These features were replicated in mice deficient in syndecan-4, the major heparan sulfate
proteoglycan expressed on the DC surface: Tumors were growth-impaired in syndecan-4–deficient mice and were
characterized by increased infiltration by mature DCs. Tumors on the mutant background also showed greater
infiltration by NK cells and NKT cells. These findings indicate the genetic importance of DC heparan sulfate
proteoglycans in tumor growth and may guide therapeutic development of novel strategies to target syndecan-4
and heparan sulfate in cancer.