Bone marrow-derived myofibroblasts promote colon tumorigenesis through the IL-6/JAK2/STAT3 pathway

•BMFs and BMF-CM induced cancer stem cell-like sphere formation of colon cancer cells.•Colon cancer cells stimulated BMFs to produce IL-6.•IL-6/STAT3 signaling contributes to the sphere formation of colon cancer cells.•BMFs promoted tumorigenesis and tumor growth of mouse colon cancer cells in mice.•This study demonstrates the roles of BMFs in promoting colon tumorigenesis.

Bone marrow-derived myofibroblasts (BMFs) have been shown to promote tumor growth. Here, we found that BMFs or BMF conditioned medium (BMF-CM) induced cancer stem cell-like sphere formation of colon cancer cells. The co-cultured BMFs, but not co-cultured cancer cells, expressed higher levels of IL-6 than BMFs or cancer cells cultured alone. Anti-mouse IL-6 neutralizing antibody, JAK2 inhibitors and STAT3 knockdown in mouse cancer cells reduced BMF- and BMF-CM-induced sphere formation of colon cancer cells. When co-injected, BMFs significantly enhanced tumorigenesis of colon cancer cells in mice. Our results demonstrate that BMFs promote tumorigenesis via the activation of the IL-6/JAK2/STAT3 pathway.