Cancer-Associated Fibroblasts Expressing Sulfatase 1 Facilitate VEGFA-Dependent Microenvironmental Remodeling to Support Colorectal Cancer.

Tumor stroma plays a critical role in fostering tumor progression and metastasis. Cancer-associated fibroblasts (CAF) are a major component of the tumor stroma. Identifying the key molecular determinants for the protumor properties of CAFs could enable the development of more effective treatment strategies. In this study, through analyses of single-cell sequencing data, we identified a population of CAFs expressing high levels of sulfatase 1 (SULF1), which was associated with poor prognosis in patients with colorectal cancer. Colorectal cancer models using mice with conditional SULF1 knockout in fibroblasts revealed the tumor-supportive function of SULF1+ CAFs. Mechanistically, SULF1+ CAFs enhanced the release of VEGFA from heparan sulfate proteoglycan. The increased bioavailability of VEGFA initiated the deposition of extracellular matrix and enhanced angiogenesis. In addition, intestinal microbiota-produced butyrate suppressed SULF1 expression in CAFs through its histone deacetylase (HDAC) inhibitory activity. The insufficient butyrate production in patients with colorectal cancer increased the abundance of SULF1+ CAFs, thereby promoting tumor progression. Importantly, tumor growth inhibition by HDAC was dependent on SULF1 expression in CAFs, and patients with colorectal cancer with more SULF1+ CAFs were more responsive to treatment with the HDAC inhibitor chidamide. Collectively, these findings unveil the critical role of SULF1+ CAFs in colorectal cancer and provide a strategy to stratify patients with colorectal cancer for HDAC inhibitor treatment.  Significance: SULF1+ cancer-associated fibroblasts play a tumor-promoting role in colorectal cancer by stimulating extracellular matrix deposition and angiogenesis and can serve as a biomarker for the therapeutic response to HDAC inhibitors in patients.