CCL2 promotes lymphatic metastasis via activating RhoA and Rac1 pathway and predict prognosis to some extent in tongue cancer

BACKGROUND: Oral tongue cancer is an extremely malignant tumor with high rate of lymphatic metastasis. Little is known about its invasion and metastasis mechanisms so far. METHODS: To clarify the main role of CCL2 in tongue cancer progression, we performed Transwell migration assay to confirm the effects of different concentrations of CCL2 on the migration and invasion of tongue cancer cells. Next, by siRNA interference of RhoA and Rac1 in LNMTca8113 cells, we are able to observe that these two molecules block the effect of CCL2 on cell migration and cytoskeleton reorganization by laser confocal microscopy. Moreover, the AKT phosphorylation level of PI3K downstream molecule under the action of CCL2 also be detected by qRT-PCR and western blot, so as to determine whether CCL2 affects the proliferation of LNMTca8113 cells through PI3K/AKT pathway. Finally, we analyzed the relationship between plasma CCL2 level and various clinicopathological parameters in patients with tongue cancer. Results: We found that tongue cancer cells treated with CCL2 migrate faster at first. CCL2 may enhance the invasion and migration of LNMTca8113 cells by activating RhoA and Rac1 to promote cytoskeleton reorganization. Promotion of LNMTca8113 migration induced by CCL2 was inhibited by silence of RhoA and Rac1. CCL2 could increase the phosphorylation of downstream Akt/PI3K signal and promoted the proliferation. Plasma concentration confirmed that the CCL2 level was closely related to the clinical stage of tongue cancer. Patients with lower CCL2 levels had a relatively longer progression-free survival and total survival time. RESULTS: After adding CCL2, the number of proliferation and migration of tongue cancer cells increased and the expression of RhoA and Rac1 rose up in LNMTca8113 cell line. The cytoskeleton reorganization was notable. Patients with higher serum levels of CCL2 had shorter progression-free survival than those with lower levels of CCL2 (P < 0.0001). CONCLUSIONS: CCL2 promotes the invasion and metastasis of tongue cancer by PI3K/Akt pathway. The plasma level of CCL2 may predict prognosis of tongue cancer patients. CCL2 can serve as a potential therapeutic target for tongue cancer treatment.