Extracellular nicotinamide phosphoribosyltransferase visfatin activates JAK2-STAT3 pathway in cancer-associated fibroblasts to promote colorectal cancer metastasis.

Background: Metastasis is one of the major challenges in the treatment of colorectal cancer (CRC), during which cancer-associated fibroblasts (CAFs) in the tumor microenvironment are critically involved.

Objective: In this study, we aim to explore the regulatory role of extracellular nicotinamide phosphoribosyltransferase Visfatin and its impact on CRC metastasis.

Methods: To examine the effect of visfatin on CAFs, human CRC tissue-derived CAFs were exposed to visfatin, and the expression of inflammatory factors, activation of JAK-STAT pathway and production of ROS in CAFs were assessed. To examine the effect of visfatin-treated CAFs on CRC metastasis, human CRC cell line SW480 or SW620 were cultured with the conditioned medium derived from visfatin-treated CAFs, and the invasion and migration ability of SW480 or SW620 cells were evaluated by transwell migration and matrigel invasion assays.

Results: Our previous study found that visfatin, a secreted form of nicotinamide phosphoribosyltransferase that governs the rate-limiting step of NAD synthesis, promoted CRC metastasis. However, little is known about the effect of visfatin on CAFs. The conditioned medium derived from visfatin- treated CAFs promotes the migratory and invasive capability of CRC cells, and enhance lung metastasis in mouse model. Visfatin treatment stimulated the expression of a couple of inflammatory factors in CAFs, which was mediated by visfatin-induced activation of JAK- STAT pathway and accumulation of ROS. Inhibition of JAK-STAT pathway or neutralization of cellular ROS attenuated visfatin-mediated migration and invasion of CRC cells.

Conclusions: The present work highlights a critical role of visfatin in the crosstalk between CRC cells and CAFs, which moonlight as a non-metabolic extracellular signal molecule to hijacks JAK-STAT pathway in CAFs to promote CRC metastasis.