(30) PUFAs and NSAIDs inhibit lung cancer metastatic process through Rho GTPase signaling

Objective : Ras-related C3 botulinum toxin substrate (Rac1) and Cell division control protein 42 (Cdc42) GTPases play critical roles in cancer cell metastasis. Omega-3 polyunsaturated fatty acids (PUFAs) and non-steroidal anti-inflammatory drugs (NSAIDs) show anticancer activities through diverse molecular mechanisms. We have already demonstrated that combining NSAIDs with PUFAs was more effective at altering the expression of critical proteins in the RAS/MEK/ERK and PI3K/Akt pathways. We studied the ability of selected NSAIDs and omega-3 PUFAs combination to inhibit lung cancer cell invasion and determine their impact on Rho GTPase signaling in the metastatic process.

Methods: We conducted western blotting to detect Rho GTPases (RhoA, Rac1, and CDC42) in A549, NCI-H1299, and NCI-H1975 cells after exposure to PUFAs and NSAIDs. We further examined the effect of co-treatment on NSCLC cell migration and invasion. Western blot analysis detected the expression of marker proteins in EMT.

Results: Exposure of A549, H1975, and H1299 cells to DHA, EPA or E-EPA, and diclofenac or ketorolac resulted in suppression of both the distance of migration, the number of cells that migrated into the wounded and cell invasion. Furthermore, co-treatment with DHA and diclofenac disrupted actin filament assembly and inhibited cell migration and invasion. In addition, the co-treatment resulted in altered expression of Rho GTPases and the marker proteins involved in EMT by increasing expression of the epithelial marker, E-cadherin, while downregulating the expressions of mesenchymal markers, N-cadherin, Fibronectin and Vimentin, ZEB1, and β-catenin.

Conclusions: The data from this study demonstrate that co-treatment with PUFAs and low-dose NSAIDs suppressed NSCLC cell motility and invasion, is associated with inhibition of the Rho GTPase activity and provides more significant anticancer potential in preventing or controlling NSCLC metastasis.