Toll-like receptor 2 stimulation promotes colorectal cancer cell growth via PI3K/Akt and NF-κB signaling pathways

Toll-like receptor (TLR) 2 is a key regulator of innate immune responses and has been shown to play an important role in inflammation-associated cancers. In this study, we aimed to evaluate the role of TLR2 in colorectal cancer (CRC). We demonstrated that TLR2 mRNA and protein expression was significantly upregulated in tumors from CRC patients and indicated poor prognosis. Using the TLR2 agonist Pam3Cys (P3C) to activate TLR2 signaling in human CRC cell lines, we showed that TLR2 drives cellular proliferation, which was dependent upon PI3K/Akt and NF-kappa B signaling pathways and was associated with the upregulation of anti-apoptotic genes BCL2A1, WISP1 and BIRC3. Likewise, pharmacological blockade of PI3K/Akt and NF-kappa B pathways mitigated the CRC pro-survival effects of TLR2 stimulation. Furthermore, genetic ablation of TLR2 using CRISPR/Cas9 suppressed CRC cell proliferation, invasion and migration. Taken together, these findings demonstrate that TLR2 plays an important role in colorectal tumorigenesis and may represent a promising therapeutic target in CRC.