Polyunsaturated fatty acids (PUFAs) and non-steroidal anti-inflammatory drugs (NSAIDs) show anticancer activities through diverse molecular mechanisms. However, the anticancer capacities of either PUFAs or NSAIDs alone is limited. We examined whether combining NSAIDs with docosahexaenoic (DHA), commonly derived from fish oils, would possibly synergize their anticancer activity. We determined the viability of lung cancer cell lines (NCI-H1573, A549, NCI-H1299, and NCI-H1975) after exposure to DHA and various NSAIDs. We further conducted cell apoptosis assays and analyzed apoptosis-associated proteins and some key proteins in the RAS/MEK/ERK and PI3K/Akt pathways using western blot analysis. We also determined the impact of the treatment on the expression of inducible cancer-related genes using nCounter PanCancer Pathways gene expression analysis. The results showed that the combination of DHA and NSAIDs increased suppression of cell viability in all the lung cancer cell lines tested compared to each of the compounds used alone, with diclofenac being the most potent NSAID tested. This synergistic effect is especially significant in A549 and NCI-H1573 cells. The combination treatment was more effective at inhibiting clonogenic cell growth and anchorage-independent growth in soft agar, inducing caspase-dependent apoptosis, and altering expression of critical proteins in the RAS/MEK/ERK and PI3K/Akt pathways. The data from this study demonstrate that DHA combined with low dose diclofenac provides greater anticancer potential, which can be further developed for chemoprevention and adjunct therapy in lung cancer.

The tuberous sclerosis complex (TSC) is a rare genetic syndrome and multisystem disease resulting in tumor formation in major organs. A molecular hallmark of TSC is a dysregulation of the mammalian target of rapamycin (mTOR) through loss-of-function mutations in either tumor suppressor TSC1 or TSC2. Here, we sought to identify drug vulnerabilities conferred by TSC2 tumor-suppressor loss through cell-based chemical biology screening. Our small-molecule chemical screens reveal a sensitivity to inhibitors of checkpoint kinase 1/2 (CHK1/2), regulators of cell cycle, and DNA damage response, in both in vitro and in vivo models of TSC2-deficient renal angiomyolipoma (RA) tumors. Further, we performed transcriptional profiling on TSC2-deficient RA cell models and discovered that these recapitulate some of the features from TSC patient kidney tumors compared to normal kidneys. Taken together, our study provides a connection between mTOR-dependent tumor growth and CHK1/2, highlighting the importance of CHK1/2 inhibition as a potential antitumor strategy in TSC2-deficient tumors.

Background Low survival rates of lung cancer patients and high recurrence rate in non‐small cell lung cancer (NSCLC) patients have been attributed to metastasis. The aberrant signaling of GTPases, such as the Rho family of GTPases (Cdc42, Rac1, and RhoA) have been implicated in lung cancer metastasis. Several studies indicate that cyclooxygenases (COX) inhibitors and omega‐3 polyunsaturated fatty acids (PUFAs) may help prevent cell migration and invasion, which are critical steps in cancer cell metastasis. We previously reported the inhibitory effect of co‐treatment with docosahexaenoic acid (DHA) and diclofenac on the expression of hyperactive small GTPases. This study aimed to investigate the potential anti‐metastatic effects of such co‐treatment on NSCLC cancer cells as well as to investigate the related mechanisms. Methods We conducted western blotting to detect Rho GTPases (RhoA, Rac1, and CDC42) in A549, NCI‐H1299, and NCI‐H1975 cells after exposure to DHA and diclofenac. We also conducted immunostaining analyses of F‐actin organization and Rho GTPases in A549 cells. We further examined the effect of co‐treatment on NSCLC cell migration and invasion. Expression of marker proteins in EMT and MMP‐2/9 were detected by western blot analysis. Results Co‐treatment with DHA and diclofenac disrupted actin filament assembly as well as inhibited cell migration and invasion. Exposure of A549 cells to DHA (5 μM) and diclofenac (25 μM) resulted in suppression of both the distance of migration by 58.1 ± 2.8% as well as the number of cells that migrated into the wounded area by 62.2 ± 1.8%. In addition, the co‐treatment resulted in altered expression of marker proteins involved in EMT by increasing expression of epithelial marker, E‐cadherin, while downregulating the expressions of mesenchymal markers, N‐cadherin, Fibronectin and Vimentin, ZEB1, and β‐catenin. Conclusions Our findings indicate that co‐treatment with diclofenac and DHA suppressed NSCLC cell motility and invasion, and is associated with disruption of the actin cytoskeleton and inhibition of the Rho GTPase activity. Our findings suggest that combination of diclofenac and DHA could potentially prevent or control NSCLC metastasis.