Honokiol inhibits epithelial-mesenchymal transition and hepatic fibrosis via activation of Ecadherin/GSK3ß/JNK and inhibition of AKT/ERK/p38/ß-catenin/TMPRSS4 signaling axis.

Though Honokiol was known to have anti-inflammatory, antioxidant, anticancer, antithrombotic, anti-viral, metabolic, antithrombotic, and neurotrophic activities, the underlying mechanisms of Honokiol on epithelial-mesenchymal transition (EMT) mediated liver fibrosis still remain elusive so far. Anti-EMT and antifibrotic effects of Honokiol were explored in murine AML-12 hepatocyte cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, wound healing assay, Western blotting and also in CCl4-induced liver injury mouse model by immunohistochemistry. Honokiol significantly suppressed transforming growth factor ß1 (TGF-ß1)-induced EMT and migration of AML-12 cells along with decreased EMT phenotypes such as loss of cell adhesion and formation of fibroblast like mesenchymal cells in TGF-ß1-treated AML-12 cells. Consistently, Honokiol suppressed the expression of Snail and transmembrane protease serine 4 (TMPRSS4), but not p-Smad3, and activated E-cadherin in TGF-ß1-treated AML-12 cells. Additionally, Honokiol reduced the expression of ß-catenin, p-AKT, p-ERK, p-p38 and increased phosphorylation of glycogen synthase kinase 3 beta (GSK3ß) and JNK in TGF-ß1-treated AML-12 cells via TGF-ß1/nonSmad pathway. Conversely, GSK3ß inhibitor SB216763 reversed the ability of Honokiol to reduce Snail, ß-catenin and migration and activate E-cadherin in TGF-ß1-treated AML-12 cells. Also, Honokiol suppressed hepatic steatosis and necrosis by reducing the expression of TGF-ß1 and α-SMA in liver tissues of CCl4 treated mice. These findings provide scientific evidence that Honokiol suppresses EMT and hepatic fibrosis via activation of E-cadherin/GSK3ß/JNK and inhibition of AKT/ERK/p38/ß-catenin/TMPRSS4 signaling axis.

Inhibition of TMPRSS4 mediated epithelial-mesenchymal transition is critically involved in antimetastatic effect of melatonin in colorectal cancers.

In the current study, the underlying anti-metastatic mechanism of melatonin contained in some edible plants was explored in association with transmembrane protease serine 4 (TMPRSS4) mediated metastasis and epithelial-mesenchymal transition (EMT) signaling in human HCT15 and SW620 colorectal cancer cells. Here, TMPRSS4 was highly expressed in HCT15, but was weakly expressed in SW620 cells. Melatonin exerted weak cytotoxicity, decreased invasion, adhesion, and migration, and attenuated the expression of TMPRSS4, cyclin E, pro-urokinase-type plasminogen activator (pro-uPA), p-signal transducer and activator of transcription 3 (p-STAT3), p-focal adhesion kinase (p-FAK), Snail and increased the expression of E-cadherin, p27, pp38 and p-Jun N-terminal kinases (p-JNK) in HCT15 cells. Conversely, overexpression of TMPRSS4 reduced the ability of melatonin to activate E-cadherin and reduce Snail. Furthermore, even in SW620 cells transfected with TMPRSS4-overexpression plasmid, melatonin effectively suppressed invasion and migration along with decreased expression of Snail, cyclin A, cyclin E, pro-uPA and p-FAK and increased expression of E-cadherin and p27. Overall, these findings provide evidence that melatonin suppresses metastasis in colon cancer cells via inhibition of TMPRSS4 mediated EMT.

Galbanic acid potentiates TRAIL induced apoptosis in resistant non-small cell lung cancer cells via inhibition of MDR1 and activation of caspases and DR5.

Galbanic acid (GBA) is known a sesquiterpene coumarin to have apoptotic, anti-hypoxic, anti-proliferative, anti-hepatitis, anti-angiogenic, anti-bacteria and anti-thrombotic effects. Also, antitumor effect of GBA was reported in prostate, ovary, breast and lung cancers. Nevertheless, the underlying molecular mechanism of GBA was not fully understood to overcome chemoresistance in resistant lung cancer so far. Thus, synergistic antitumor mechanism of GBA and TNF-related apoptosis-inducing ligand (TRAIL) was elucidated in H460 and resistant H460/R non-small cell lung cancer cells (NSCLCs). Combination of GBA and TRAIL significantly exerted cytotoxicity in a dose dependent manner compared to GBA or TRAIL alone in H460/R cells. Also, GBA and TRAIL significantly increased the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells and sub-G1 population in a dose dependent manner in H460/R cells. Consistently, GBA and TRAIL induced cleavages of poly (ADP-ribose) polymerase (PARP), caspase-9 and caspase-8 along with upregulation of death receptor 5 (DR5) and also attenuated the expression of B-cell lymphoma-extra-large (Bcl-xL), B-cell lymphoma 2 (Bcl-2), X-linked inhibitor of apoptosis protein (XIAP) in H460/R cells. Furthermore, combination of GBA and TRAIL remarkably inhibited the expression of decoy receptor 1 (DcR1) and multidrug resistance 1(MDR1) in H460/R cells. Consistently, GBA and TRAIL effectively maintained Rhodamine 123 accumulation in H460/R cells compared to GBA or TRAIL alone by blocking multidrug efflux pump from the cells. Overall, our findings suggest that galbanic acid enhances TRAIL induced apoptosis via inhibition of MDR1 and activation of caspases and DR5 in H460/R cells as a potent TRAIL sensitizer.

Quinoline derivative KB3-1 potentiates paclitaxel induced cytotoxicity and cycle arrest via multidrug resistance reversal in MES-SA/DX5 cancer cells.

AIMS: The resistance to chemotherapeutic drugs is a major problem for successful cancer treatment. Multidrug resistance (MDR) phenotype is characterized by over-expression of P-glycoprotein (P-gp) on the cancer cell plasma membrane that extrudes drugs out of the cells. Therefore, novel MDR reversal agents are desirable for combination therapy to reduce MDR and enhance anti-tumor activity. Thus, the present study was aimed to evaluate the potent efficacy of novel quinoline derivative KB3-1 as a potent MDR-reversing agent for combined therapy with TAX. MAIN METHODS: MDR reversing effect and TAX combined therapy were examined by Rhodamine accumulation and efflux assay and Confocal immunofluorescence microscopy, Western blotting, TUNEL assay, and cell cycle analysis. KEY FINDINGS: The discovery of quinoline-3-carboxylic acid [4-(2-[benzyl-3[-(3,4-dimethoxy-phenyl)-propionyl]-amino]-ethyl)-phenyl]-amide (KB3-1) as a novel MDR-reversal agent. KB3-1 significantly enhanced the accumulation and retention of a P-gp substrate, rhodamine-123 in the P-gp-expressing MES-SA/DX5 uterine sarcoma cells but not in the P-gp-negative MES-SA cells at non-toxic concentrations of 1 microM and 3 microM. Similarly, fluorescence microscopy observation revealed that KB3-1 reduced the effluxed rhodamine-123 expression on the membrane of MES-SA/DX5 cells. Consistent with decreased P-gp pumping activity, confocal microscopic observation revealed that KB3-1 effectively diminished the expression of P-gp in paclitaxel (TAX)-treated MES-SA/DX-5 cells. Furthermore, Western blotting confirmed that KB3-1 reduced P-gp expression and enhanced cytochrome C release and Bax expression in TAX treated MES-SA/DX-5 cells. In addition, KB3-1 enhanced TAX-induced apoptotic bodies in MES-SA/DX5 cells by TdT-mediated-dUTP nick-end labeling (TUNEL) staining assay aswell as potentiated TAX- induced cytotoxicity, G2/M phase arrest and sub-G1 apoptosis in MES-SA/DX5 cells but not in MES-SA cells. Interestingly, KB3-1 at 3 microM had comparable MDR-reversal activity to 10 microM verapamil, a well-known MDR- reversal agent. SIGNIFICANCE: KB3-1 can be a MDR-reversal drug candidate for combination chemotherapy with TAX.