C-C motif chemokine ligand 14 inhibited colon cancer cell proliferation and invasion through suppressing M2 polarization of tumor-associated macrophages.

Background Colon cancer is one of the most common cancers with a high incidence and high mortality. Chemokines play a crucial role in the development of cancer. Methods Here, qRT-PCR was performed to detect gene expression. Western blot and immunohistochemistry were implemented to examine the expression of C-C motif chemokine ligand 14 (CCL14) in colon tumors. Besides, the expression of CD68 and CD206 in tumors was measured by immunohistochemistry. The percentages of M1- and M2-polarized macrophages were detected by flow cytometry. Furthermore, CCK-8 assay was performed to detect cell proliferation, and Transwell assay for cell invasion. Results CCL14 was decreased in both colon tumors and colon cancer cells, and many tumor-associated macrophages (TAMs) infiltrated into the tumor. An increase CCL14 inhibited colon cancer cell proliferation. Importantly, CCL14 promoted THP-1 to M1 polarization induced by LPS and IFN-γ, and inhibited THP-1 to M2 polarization induced by IL-4 and IL-13. Besides, CCL14 enhanced the inhibition of M1-polarized macrophages to colon cancer cell proliferation and invasion, but reversed the promotion of M2-polarized macrophages to cell proliferation and invasion. Conclusion Our data demonstrated that CCL14 inhibited the proliferation and invasion of colon cancer cells through suppressing the formation of M2-like TAMs.