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Multidrug resistance (MDR) remains the most difficult problem facing conventional chemotherapy for cancers. Astragalus membranaceus is a historically traditional Chinese medicine. One of its bioactive components, formononetin, exhibits antitumor effects on various cancers. However, the effects of formononetin on MDR cancers have not been evaluated. Therefore, we investigated the defense's effects of formononetin on MDR. We used rhodamine 123 and doxorubicin efflux assays to analyze the inhibition kinetics of P-glycoprotein (P-gp) mediated-efflux. Cell viability was detected by sulforhodamine B assay, and the synergistic effects of formononetin combined with chemotherapeutic agents were further calculated using CompuSyn software. Molecular docking was performed with iGEMDOCK. We discovered that formononetin considerably induced oxidative stress and the disruption of mitochondrial membrane potential in MDR cancer cells. Furthermore, formononetin inhibits the P-gp efflux function by ATPase stimulation and the uncompetitive inhibition of P-gp-mediated effluxes of rhodamine 123 and doxorubicin. The molecular docking model indicates that formononetin may bind to P-gp by strong hydrogen bonds at Arginine (Arg) 489 and Glutamine (Gln) 912. Formononetin exhibits significant synergistic effects with vincristine and doxorubicin toward MDR cancer cells, and it synergistically suppressed tumor growth in vivo with paclitaxel. These results suggest that formononetin should be seen as a potential candidate for the adjuvant therapy of MDR cancers. [ABSTRACT FROM AUTHOR]

Background: Angiogenesis is primarily attributed to the excessive proliferation and migration of endothelial cells. Targeting the vascular endothelial growth factor (VEGF) is therefore significant in anti-angiogenic therapy. Although these treatments have not reached clinical expectations, the upregulation of alternative angiogenic pathways (endoglin/Smad1) may play a critical role in drug (VEGF-neutralizing agents) resistance. Enhanced endoglin expression following a VEGF-neutralizing therapy (semaxanib®) was noted in patients. Treatment with an endoglin-targeting antibody augmented VEGF expression in human umbilical vein endothelial cells (HUVECs). Therefore, approaches that inhibit both the androgen and VEGF pathways enhance the HUVECs cytotoxicity and reverse semaxanib resistance. The purpose of this study was to find natural-occurring compounds that inhibited the endoglin-targeting pathway. Methods: Curcuminoids targeting endoglin were recognized from two thousand compounds in the Traditional Chinese Medicine Database@Taiwan (TCM Database@Taiwan) using Discovery Studio 4.5. Results: Our results, obtained using cytotoxicity, migration/invasion, and flow cytometry assays, showed that curcumin (Cur) and demethoxycurcumin (DMC) reduced angiogenesis. In addition, Cur and DMC downregulated endoglin/pSmad1 phosphorylation. Conclusions: The study first showed that Cur and DMC demonstrated antiangiogenic activity via the inhibition of endoglin/Smad1 signaling. Synergistic effects of curcuminoids (i.e., curcumin and DMC) and semaxanib on HUVECs were found. This might be attributed to endoglin/pSmad1 downregulation in HUVECs. Combination treatment with curcuminoids and a semaxanib is therefore expected to reverse semaxanib resistance. [ABSTRACT FROM AUTHOR]

Trilinolein has been identified as one of the active constituents isolated from Panax notoginseng used widely in traditional Chinese medicine. Protective actions of Panax notoginseng against cerebral ischemia, beneficial effects on the cardiovascular system, and hemostatic, antioxidant, hypolipidemic, hepatoprotective, renoprotective and estrogen-like activities have been illustrated. In the present study, the effects of trilinolein on the growth of non-small cell lung carcinoma A549 were investigated. It was found that the exposure of A549 cells to trilinolein resulted in the growth inhibition and the induction of apoptosis in a dose- and time- dependent manner. Trilinolein treatment induced the upregulation of pro-apoptotic Bax, downregulation of anti-apoptotic Bcl-2 expression, which was associated with the proteolytic activation of caspases and the concomitant degradation of poly(ADP-ribose) polymerase (PARP) protein. Intracellular reactive oxygen species seem to play a role in the trilinolein-induced apoptosis, since ROS were produced early in the trilinolein treatment. Moreover, the activity of PI3K/Akt was downregulated in trilinolein-treated cells. Our results demonstrated that the most important regulators of trilinolein-induced apoptosis are Bcl-2 family and caspase-3, which are associated with cytochrome c release and dephosphorylation on the Akt signaling pathway. [ABSTRACT FROM AUTHOR]

Abstract: Aims of the study: Cardiospermum halicacabum (CH) has been used in Chinese medicine for a long time. However, its fingerprint chromatogram, antioxidant, anti-inflammatory effects and mechanism are still needed to be explored. Therefore, the aims of this study investigated the antioxidant and anti-inflammatory effects of CH extracts and its reference compounds ex vivo and in vivo. Materials and methods: In HPLC analysis, the fingerprint chromatogram of ethanolic extract of CH (ECH) was established. The effects of ACH (aqueous extract of CH) and ECH extracts were assessed for the antioxidant and LPS-induced NO production in RAW264.7 cells. In vivo anti-inflammatory activities of ECH were evaluated in mouse paw edema induced by λ-carrageenan (Carr). We investigate the anti-inflammatory mechanism of ECH via studies of the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in the liver and the levels of malondialdehyde (MDA) and nitrite oxide (NO) in the edema paw. Serum NO and TNF-α were also measured. Results: ECH had better antioxidant activity than that of ACH. In the anti-inflammatory test, ECH inhibited the development of paw edema induced by Carr and increased the activities of CAT, SOD and GPx in the liver tissue. ECH also decreased the level of NO in edematous paw tissue and in serum level, and diminished the level of serum TNF-α at the fifth hour after Carr injection. Conclusions: ECH exerts anti-inflammatory effects by suppressing TNF-α and NO. The anti-inflammatory mechanism of ECH might be related to the decrement of the level of MDA in the edema paw via increasing the activities of CAT, SOD and GPx in the liver. The results showed that ECH might serve as a natural antioxidant and anti-inflammatory agent. [Copyright &y& Elsevier]

As the redundancy between endoglin and VEGF signaling in angiogenesis were confirmed. Increased endoglin signaling was found in a semaxanib-treated HUVECs; and vice versa in endothelial cells. Our results showed that combined targeting of the endoglin and VEGF pathway significantly increased antiangiogenic effects in vitro. • Combined targeting to endoglin and VEGF increase antiangiogenic effects. • EGCG significantly inhibited endoglin upregulation after semaxanib-treated HUVECs. • EGCG signicantly decreased the semantinib-induced endoglin overexpression. • Combines EGCG with semaxanib overcome drug resistance. Strategies targeting endoglin are currently being investigated in clinical trials as an anti-angiogenic therapy. The redundancy between endoglin and vascular endothelial growth factor (VEGF) signaling in angiogenesis was verified. Increased endoglin signaling after an anti-VEGF treatment was observed in patients. Treatment with an endoglin-neutralizing antibody increased VEGF signaling in endothelial cells. Therefore, strategies targeting both the endoglin and VEGF pathways were applied to determine whether the anti-angiogenic effects were increased in vitro. Five possible hits for endoglin were identified from 2000 compounds in the Traditional Chinese Medicine Database using Discovery Studio 4.5 Epigallocatechin-3-gallate (EGCG) attenuates angiogenesis by downregulating VEGF; however, researchers have not determined whether its anti-angiogenic effects are mediated by endoglin/Smad1 signaling. A major contribution of this study is that EGCG significantly inhibited the upregulation of endoglin in semaxanib-treated human umbilical vein endothelial cell. Thus, a combination treatment with EGCG and a VEGF tyrosine kinase inhibitor would be appropriate to reverse drug resistance. EGCG alone significantly decreased endoglin/pSmad1 levels in HUVECs. In the angiogenesis assay, the migration, invasion, and tube formation of HUVECs were markedly suppressed by higher concentrations of EGCG. A combination treatment with EGCG and semaxanib further produced increased anti-angiogenic effects. The main contribution of the study indicated that EGCG significantly decreased the semaxanib-induced overexpression of endoglin. Therefore, a combination treatment including EGCG will probably solve the drug resistance to anti-VEGF treatments. [ABSTRACT FROM AUTHOR]