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.