fh535 and Lung-Neoplasms

Surgery is the major treatment method for non-small cell lung cancer. It has been reported that plasma PGE2 level is increased following surgery and stress which promotes lung cancer metastasis. In the present study, two animal models were used to confirm the effects of exogenous and endogenous prostaglandin E2 (PGE2) on metastasis of lung cancer cells. We found that both PGE2 level and A549 metastasis were enhanced in mice with unilateral pulmonary resection following tail vein injection of lung cancer A549 cells. Both endogenous PGE2 level and pulmonary metastatic nodules were significantly reduced by celecoxib. A549 metastases were increased in mice after exogenous PGE2 injection. In the animal models, celecoxib inhibited lung cancer cell metastasis induced by exogenous PGE2. Therefore, we focused on the effects of celecoxib on the downstream pathway of PGE2 in vitro and found that celecoxib inhibited PGE2-induced A549 migration and invasion, which were evaluated by wound healing and Transwell experiments. The expression of protein and mRNA of MMP9 and E-cadherin following treatment with PGE2 were suppressed and increased by celecoxib, respectively; however, MMP2 showed no change. A549 cell invasion and up-regulation of the expression of MMP9 and down-regulation of E-cadherin induced by PGE2 were inhibited by FH535, an inhibitor of β-catenin. Deletion of β-catenin by siRNA abrogated celecoxib-induced inhibition of MMP9 up-regulation and E-cadherin down-regulation by treatment of PGE2. Furthermore, we found that the level of β-catenin together with GSK-3β phosphorylation was inhibited by celecoxib. In conclusion, celecoxib inhibits metastasis of A549 cells in the circulation enhanced by PGE2 after surgery by not only inhibiting endogenous PGE2 expression, but also by suppression downstream of PGE2 via the GSK-3β-β-catenin pathway.

Topics: Animals; Antigens, CD; beta Catenin; Cadherins; Celecoxib; Cell Line, Tumor; Cell Proliferation; Dinoprostone; Down-Regulation; Female; Gene Deletion; Gene Expression Regulation, Neoplastic; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Lung Neoplasms; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Inbred BALB C; Neoplasm Metastasis; Phosphorylation; Pyrazoles; RNA, Messenger; RNA, Small Interfering; Sulfonamides; Up-Regulation

Taxanes, such as docetaxel and taxol, have been used as firstline chemotherapies in advanced lung adenocarcinoma (LAD), but limited responses to chemotherapy remain a major impediment in the clinic. Treatment with 5-azacytidine increases the sensitivity of SPC-A1/DTX cell line to taxanes. The results of DNA methylation microarray and cDNA array analysis indicate that DNA methylation contributes to the downregulation of secreted frizzled related protein 1 (SFRP1) in SPC-A1/DTX cells. Overexpression of SFRP1 reverses the chemoresistance of taxane-resistant LAD cell lines and enhances the in vivo sensitivity of taxane-resistant LAD cells to taxanes. Meanwhile, short hairpin RNA (shRNA)-mediated SFRP1 knockdown decreases the sensitivity of parental LAD cell lines to taxanes. Furthermore, FH535, a reversible Wnt signaling inhibitor, enhances the sensitivity of taxane-resistant LAD cells to taxanes. The level of SFRP1 in tumors of nonresponding patients is significantly lower than that in tumors of responders. Taken together, our results provide the direct evidence that SFRP1 is a clinically important determinant of taxanes resistance in human LAD cells, suggesting that SFRP1 might be a novel therapeutic target for the treatment of taxane-resistant LAD patients.

Topics: Adenocarcinoma; Adenocarcinoma of Lung; Animals; Antineoplastic Agents; Azacitidine; Bridged-Ring Compounds; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; DNA Methylation; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Intercellular Signaling Peptides and Proteins; Lung Neoplasms; Male; Membrane Proteins; Mice, Inbred BALB C; Oligonucleotide Array Sequence Analysis; Sulfonamides; Taxoids; Wnt Signaling Pathway; Xenograft Model Antitumor Assays

Lung cancer remains a leading cause of death due to its metastasis to distant organs. We have examined the effect of honokiol, a bioactive constituent from the Magnolia plant, on human non-small cell lung cancer (NSCLC) cell migration and the molecular mechanisms underlying this effect. Using an in vitro cell migration assay, we found that treatment of A549, H1299, H460 and H226 NSCLC cells with honokiol resulted in inhibition of migration of these cells in a dose-dependent manner, which was associated with a reduction in the levels of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2). Celecoxib, a COX-2 inhibitor, also inhibited cell migration. Honokiol inhibited PGE2-enhanced migration of NSCLC cells, inhibited the activation of NF-κB/p65, an upstream regulator of COX-2, in A549 and H1299 cells, and treatment of cells with caffeic acid phenethyl ester, an inhibitor of NF-κB, also inhibited migration of NSCLC cells. PGE2 has been shown to activate β-catenin signaling, which contributes to cancer cell migration. Therefore, we checked the effect of honokiol on β-catenin signaling. It was observed that treatment of NSCLC cells with honokiol degraded cytosolic β-catenin, reduced nuclear accumulation of β-catenin and down-regulated matrix metalloproteinase (MMP)-2 and MMP-9, which are the down-stream targets of β-catenin and play a crucial role in cancer cell metastasis. Honokiol enhanced: (i) the levels of casein kinase-1α, glycogen synthase kinase-3β, and (ii) phosphorylation of β-catenin on critical residues Ser(45), Ser(33/37) and Thr(41). These events play important roles in degradation or inactivation of β-catenin. Treatment of celecoxib also reduced nuclear accumulation of β-catenin in NSCLC cells. FH535, an inhibitor of Wnt/β-catenin pathway, inhibited PGE2-enhanced cell migration of A549 and H1299 cells. These results indicate that honokiol inhibits non-small cell lung cancer cells migration by targeting PGE2-mediated activation of β-catenin signaling.

Topics: beta Catenin; Biphenyl Compounds; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Movement; Cell Nucleus; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Dinoprostone; Drugs, Chinese Herbal; Gene Knockdown Techniques; Humans; Lignans; Lung Neoplasms; Neoplasm Invasiveness; RNA Interference; Signal Transduction; Sulfonamides; Transcription Factor RelA