Novel isobavachalcone derivatives induce apoptosis and necroptosis in human non-small cell lung cancer H1975 cells.

In this study, seventeen isobavachalcone (IBC) derivatives (1-17) were synthesised, and evaluated for their cytotoxic activity against three human lung cancer cell lines. Among these derivatives, compound 16 displayed the most potent cytotoxic activity against H1975 and A549 cells, with IC50 values of 4.35 and 14.21 µM, respectively. Compared with IBC, compound 16 exhibited up to 4.11-fold enhancement of cytotoxic activity on human non-small cell lung cancer H1975 cells. In addition, we found that compound 16 suppressed H1975 cells via inducing apoptosis and necroptosis. The initial mechanism of compound 16 induced cell death in H1975 cells involves the increasing of Bax/Bcl-2 ratio and Cyt C protein level, down-regulating of Akt protein level, and cleaving caspase-9 and -3 induced apoptosis; the up-regulation of RIP3, p-RIP3, MLKL, and p-MLKL levels induced necroptosis. Moreover, compound 16 also caused mitochondrial dysfunction, thereby decreasing cellular ATP levels, and resulting in excessive reactive oxygen species (ROS) accumulation.

Semi-synthesis and in vitro anti-cancer effects evaluation of novel xanthohumol derivatives.

Xanthohumol (Xn) is a chalcone compound isolated from Humulus lupulus Linn., that has various biological activities. In this study, eight Xn derivatives were synthesized by Williamson, Mannich, Reimer-Tiemann, and Schiff base reactions, and evaluated for their in vitro cytotoxic activity against five human cancer cell lines (MDA-MB-231, MCF-7, CNE-2Z, SMMC-7721, and H1975). Among these compounds, 2-((E)-2,4-dihydroxy-5-((E)-3-(4-hydroxyphenyl)acryloyl)-6-methoxy-3-(3- methylbut-2-en-1-yl)benzylidene)hydrazine-1-carboximidamide (8) exhibited the most potent cytotoxic activity against the five cancer cells, with IC50 values ranging from 4.87 to 14.35 µM. Wound-healing and transwell assays showed that compound 8 inhibited the migration and invasion of MDA-MB-231 cells by down-regulation HIF-1α, MMP-2 and MMP-9 protein expression. We further demonstrated that compound 8 induced apoptosis of MDA-MB-231 cells by increasing of Bax/Bcl-2 ratio and down-regulation of Akt protein expression.

Semisynthesis and anti-cancer properties of novel honokiol derivatives in human nasopharyngeal carcinoma CNE-2Z cells.

In this study, 21 new honokiol derivatives were synthesised, and their anti-cancer properties were investigated. Among these, compound 1g exhibited the most potent cytotoxic activity against human nasopharyngeal carcinoma CNE-2Z cells, human gastric cancer SGC7901 cells, human breast cancer MCF-7 cells, and mouse leydig testicular cancer I-10 lines with IC50 values of 6.04, 7.17, 6.83, and 5.30 µM, respectively. Compared to the parental compound, 1g displayed up to 5.18-fold enhancement of the cytotoxic effect on CNE-2Z cells. We further demonstrated that 1g inhibited cell growth, suppressed migration and invasion, and induced apoptosis of CNE-2Z cells by down-regulating HIF-1α, MMP-2, MMP-9, Bcl-2, Akt and up-regulating Bax protein levels. Transfection of CNE-2Z cells with HIF-1α siRNA reduced cell migration and invasion. In addition, in vivo experiments confirmed that 1g inhibited tumour growth in CNE-2Z cell-xenografted nude mice with low toxicity. Thus, our data suggested that 1g was a potent and safe lead compound for nasopharyngeal carcinoma therapy.

Semisynthesis and in Vitro Anti-cancer Effect of New Magnolol Derivatives on the Cell Proliferation, Apoptosis, Migration, and Invasion of Human Hepatocellular Carcinoma SMMC-7721 Cells.

Four new magnolol derivatives were synthesized and evaluated for their in vitro anti-cancer properties. Among these, compound 3 showed the most potent cytotoxic activity against the SMMC-7721, SUN-449, and HepG2 human hepatocellular carcinoma cell lines, with IC50 values of 3.39, 4.11, and 6.88 µM, respectively. Compound 3 also induced apoptosis of SMMC-7721 cells by down-regulating Bcl-2 and Akt protein levels, up-regulating of Bax protein level, and cleaving caspase-9 and -3. In addition, transwell assays showed that compound 3 significantly suppressed the migration and invasion of SMMC-7721 cells, which was confirmed based on the down-regulation of hypoxia inducible factor-1α (HIF-1α), matrix metalloproteinase-2 and -9 (MMP-2, and MMP-9) protein levels.

Two new alkaloids produced by Dothideomycetes sp. BMC-101 isolated from the Magnolia grandiflora.

AbstactA total of 16 fungal strains were isolated from fresh leaves and flowers of Magnolia grandiflora and the EtOAc extracts of them were assayed for antitumor activities. Among these, the fungus Dothideomycetes sp. BMC-101 with broad spectrum inhibition was selected for further study. Four alkaloids (1-4) including two new compounds (2-(hydroxyimino)-3-phenylpropanoyl)-L-phenylalanine (1) and 8-Acetyl-bisdethiobis(methylsulfanyl)apoaranotin (4)) were isolated from Dothideomycetes sp. BMC-101. The structure of 1 was characterized with an oxime moiety formed by the condensation of two phenylalanines. To our knowledge, this is the first report on a fungal phenylalanine derivative with an oxime moiety.

Isobavachalcone Induces Multiple Cell Death in Human Triple-Negative Breast Cancer MDA-MB-231 Cells.

Standardized treatment guidelines and effective drugs are not available for human triple-negative breast cancer (TNBC). Many efforts have recently been exerted to investigate the efficacy of natural compounds as anticancer agents owing to their low toxicity. However, no study has examined the effects of isobavachalcone (IBC) on the programmed cell death (PCD) of human triple-negative breast MDA-MB-231 cancer cells. In this study, IBC substantially inhibited the proliferation of MDA-MB-231 cells in concentration- and time-dependent manners. In addition, we found that IBC induced multiple cell death processes, such as apoptosis, necroptosis, and autophagy in MDA-MB-231 cells. The initial mechanism of IBC-mediated cell death in MDA-MB-231 cells involves the downregulation of Akt and p-Akt-473, an increase in the Bax/Bcl-2 ratio, and cleaved caspases-3 induced apoptosis; the upregulation of RIP3, p-RIP3 and MLKL induced necroptosis; as well as a simultaneous increase in LC3-II/I ratio induced autophagy. In addition, we observed that IBC induced mitochondrial dysfunction, thereby decreasing cellular ATP levels and increasing reactive oxygen species accumulation to induce PCD. These results suggest that IBC is a promising lead compound with anti-TNBC activity.

Anti-Cancer Properties of Ginkgolic Acids in Human Nasopharyngeal Carcinoma CNE-2Z Cells via Inhibition of Heat Shock Protein 90.

Ginkgo biloba L. has been used in traditional Chinese medicine (TCM) for thousands of years. However, the anti-cancer properties of ginkgolic acids (GAS) isolated from G. biloba have not been investigated in human nasopharyngeal carcinoma cells. In this study, GAS exhibited an inhibitory effect on the ATPase activity of heat shock protein 90 (Hsp90) and anti-proliferative activities against four human cancer cell lines, with IC50 values ranging from 14.91 to 23.81 µg·mL-1. In vivo experiments confirmed that GAS inhibited tumor growth in CNE-2Z cell-xenografted nude mice with low hepatotoxicity. We further demonstrated that GAS suppressed migration and invasion and induced the apoptosis of CNE-2Z cells by inducing the degradation of Hsp90 client proteins (MMP-2, MMP-9, Her-2, c-Raf, Akt, and Bcl-2). Together, GAS are new Hsp90 inhibitors by binding to Hsp90 (hydrogen bond and hydrophobic interaction). Thus, GAS from G. biloba might represent promising Hsp90 inhibitors for the development of anti-nasopharyngeal carcinoma agents.

The Effect of Hispidulin, a Flavonoid from Salvia plebeia, on Human Nasopharyngeal Carcinoma CNE-2Z Cell Proliferation, Migration, Invasion, and Apoptosis.

Nasopharyngeal carcinoma (NPC) is a common malignant head and neck tumor. Drug resistance and distant metastasis are the predominant cause of treatment failure in NPC patients. Hispidulin is a flavonoid extracted from the bioassay-guided separation of the EtOH extract of Salvia plebeia with strong anti-proliferative activity in nasopharyngeal carcinoma cells (CNE-2Z). In this study, the effects of hispidulin on proliferation, invasion, migration, and apoptosis were investigated in CNE-2Z cells. The [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay and the colony formation assay revealed that hispidulin could inhibit CNE-2Z cell proliferation. Hispidulin (25, 50, 100 µM) also induced apoptosis in a dose-dependent manner in CNE-2Z cells. The expression of Akt was reduced, and the expression of the ratio of Bax/Bcl-2 was increased. In addition, scratch wound and transwell assays proved that hispidulin (6.25, 12.5, 25 µM) could inhibited the migration and invasion in CNE-2Z cells. The expressions of HIF-1α, MMP-9, and MMP-2 were decreased, while the MMPs inhibitor TIMP1 was enhanced by hispidulin. Moreover, hispidulin exhibited potent suppression tumor growth and low toxicity in CNE-2Z cancer-bearing mice at a dosage of 20 mg/kg/day. Thus, hispidulin appears to be a potentially effective agent for NPC treatment.

Semi-Synthesis and In Vitro Anti-Cancer Evaluation of Magnolol Derivatives.

Magnolol (MAG), a biphenolic neolignan, has various biological activities including antitumor effects. In this study, 15 MAG derivatives were semi-synthesized and evaluated for their in vitro anticancer activities. From these derivatives, compound 6a exhibited the best cytotoxic activity against four human cancer cell lines, with IC50 values ranging from 20.43 to 28.27 µM. Wound-healing and transwell assays showed that compound 6a significantly inhibited the migration and invasion of MDA-MB-231 cells. In addition, Western blotting experiments, performed using various concentrations of 6a, demonstrated that it downregulates the expression of HIF-1α, MMP-2, and MMP-9 in a concentration-dependent manner. Overall, these results suggest that substituting a benzyl group having F atoms substituted at the C2 position on MAG is a viable strategy for the structural optimization of MAG derivatives as anticancer agents.

Anti-cancer effects of methanol-ethyl acetate partitioned fraction from Magnolia grandiflora in human non-small cell lung cancer H1975 cells.

Non-small cell lung cancer (NSCLC) constitutes nearly 85% of all cases of lung cancer. Drug resistance, dose-limiting toxicity, and metastasis in NSCLC eventually reduce the efficacy of chemotherapeutics. In this study, we have shown that the methanol-ethyl acetate partitioned fraction from Magnolia grandiflora L. seeds (MEM) exhibit potential anti-cancer activities against NSCLC H1975 cells in vivo and in vitro. MEM significantly inhibited the proliferation of H1975 cells in a concentration- and time-dependent manner. Further, MEM exhibited potent anti-tumor efficacy and low toxicity in nude mice bearing H1975 tumors. Our study also showed that MEM could induce cellular apoptosis in H1975 cells by down-regulating the protein expression levels of Akt and p-Akt-473, and by increasing the ratio of Bax/Bcl-2. Also, MEM significantly inhibited metastasis-related cell invasion and migration of H1975 cells, which associated with the down-regulation of HIF-1α, MMP-2, and MMP-9 protein expression levels. Thus, our data shows that MEM may be an effective fraction of M. grandiflora in NSCLC treatment.

Synthesis and in vitro antitumor evaluation of honokiol derivatives.

Honokiol is a natural bioactive neolignan and has been widely researched and structural modified as an anticancer agent. In this paper, 18 honokiol derivatives were synthesized and investigated for their antitumor activity. Among these, the promising compound 5a exhibited much higher anti-proliferative activity with IC50 value of 10.41 µM. Transwell assays showed that 5a could significantly inhibit the invasion and migration of I-10 cells at 2.5 µM, which was further confirmed by the western blotting experiments with down-regulation of the HIF-1α and its associated downstream proteins MMP-2 and MMP-9. Overall, these results provided useful suggestion for further structural optimization of honokiol derivatives.

Enzymatic biosynthesis and biological evaluation of novel 17-AAG glucoside as potential anti-cancer agents.

A novel 17-allylamino-17-demethoxygeldanamycin (17-AAG) glucoside (1) was obtained from in vitro enzymatic glycosylation using a UDP-glycosyltransferase (YjiC). The water-solubility of compound 1 was approximately 10.5 times higher than that of the substrate, 17-AAG. Compound 1 showed potential anti-proliferative activities against five human cancer cell lines, with IC50 values ranging from 5.26 to 28.52 µM. Further studies also indicated that compound 1 could inhibit the growth of CNE-2Z cells by inducing the degradation of Hsp90 client proteins (Akt, c-Raf, Bcl-2, and HIF-1α). In addition, compound 1 showed greater potential anti-tumor efficacy than 17-AAG in nude mice xenografted with CNE-2Z cells. Therefore, we suggest that in vitro enzymatic glycosylation is a powerful approach for the structural optimization of 17-AAG.

Bishonokiol A inhibits breast cancer cell invasion and migration by suppressing hypoxia inducible factor-1α.

Hypoxia inducible factor-1α (HIF-1α) plays a central role in cell survival, invasion, metastasis and angiogenesis, and also is emerging as an important target in anti-cancer drug discovery. In the present study, bishonokiol A, a dimeric neolignan isolated from Magnolia grandiflora, was identified as a novel HIF-1α inhibitor. We here demonstrated that in a dose-dependent manner, bishonokiol A inhibited metastasis-related cell invasion and migration of cobalt chloride (CoCl2)-induced MCF-7 and MDA-MB-231 cells, associating with the reduction in HIF-1α levels. Transfection of MDA-MB-231 cells with HIF-1α small interfering ribonucleic acid (siRNA) resulted in a reduction in cell invasion and migration. Furthermore, we found that bishonokiol A not only inhibited the synthesis of HIF-1α protein and protein kinase B (AKT-473) phosphorylation without affecting the expression of HIF-1α mRNA or ubiquitination degradation, but also inhibited the expression of matrix metalloproteinase-9 (MMP-9) and promoter activity. Nude mice bearing MDA-MB-231 cells incubation were treated with bishonokiol A and results showed that bishonokiol A exhibited potent antitumor activity and low toxicity. Therefore, we suggest that bishonokiol A may be a potential inhibitor of HIF-1α and effective antitumor agent for breast cancer.

Design, synthesis, and apoptosis-promoting effect evaluation of novel pyrazole with benzo[d]thiazole derivatives containing aminoguanidine units.

New pyrazole with benzo[d]thiazoles containing hydrazinecarboximidamide substituent was synthesised and evaluated for cytotoxicity and apoptotic activity using the MTT assay, flow cytometry, and Western blot analysis. Among the compounds studied, (E)-2-((1-(6-((4-fluorobenzyl)oxy)benzo[d]thiazol-2-yl)-3-phenyl-1H- pyrazol-4-yl)methylene) hydrazinecarboximidamide (8l) was potent, with IC50 values of 2.41 µM, 2.23 µM, 3.75 µM and 2.31 µM in vitro anti-proliferative activity testing against triple-negative breast cancer cell line MDA-MB-231, non-triple-negative breast cancer MCF-7 cells, and human hepatocarcinoma HepG2 cells, and SMMC-7721 cells, respectively. Especially, the activity against MDA-MB-231 was similar to that of Doxorubicin, which was used as a positive control in this study. Next, the Annexin V/PI flow cytometry assay was used at different concentrations of compound 8l to demonstrate that compound 81 induced apoptosis of MDA-MB-231 cells in a concentration-dependent manner. Finally, these results were further verified by Western blot analysis. Taken together, the results of this study revealed that compound 8l may be a potential anticancer compound play a significant role in the subsequent researches.

Biosynthesis of Novel Shikonin Glucosides by Enzymatic Glycosylation.

Shikonin, a natural naphthoquinone, has attracted much attention due to its various biological activities. Two shikonin glucosides, shikonin-1',8-di-O-ß-D-glucopyranoside (1) and shikonin-1'-O-ß-D-glucopyranoside (2), were biosynthesized through in vitro enzymatic glycosylation and their structures were elucidated using spectroscopic techniques. The water-solubility and stability of compounds 1 and 2 were significantly higher than those of the parent compound. Furthermore, compound 2 showed moderate cytotoxicity against six cancer cell lines, with IC50 values ranging from 36.10 to 67.47 µM. This research indicated that in vitro enzymatic glycosylation of shikonin is an effective strategy to improve it water solubility and chemical stability.

Synthesis and Evaluation of Bakuchiol Derivatives as Potential Anticancer Agents.

A series of bakuchiol derivatives were synthesized and evaluated for their anti-proliferative and the inhibitory activities on SMMC7721 cell line migration using PX-478 as a positive control. The results showed (S,E)-4-(7-methoxy-3,7-dimethyl-3-vinyloct-1-en-1-yl)phenol (10) to have the best activity among the tested compounds, which included PX-478. In addition, compound 10 showed greater inhibitory activity than that of bakuchiol in the transwell migration and invasion assays at every dose. In western blotting tests, compound 10 showed a promising ability to downregulate the expression of HIF-1α and its associated downstream proteins MMP-2 and MMP-9. Moreover, this effect was dose-dependent and could represent a possible mechanism of action for the anticancer activity of compound 10.

3-Bromopyruvate induces apoptosis in breast cancer cells by downregulating Mcl-1 through the PI3K/Akt signaling pathway.

The hexokinase inhibitor 3-bromopyruvate (3-BrPA) can inhibit glycolysis in tumor cells to reduce ATP production, resulting in apoptosis. However, as 3-BrPA is an alkylating agent, its cytotoxic action may be induced by other molecular mechanisms. The results presented here reveal that 3-BrPA-induced apoptosis is caspase independent. Further, 3-BrPA induces the generation of reactive oxygen species in MDA-MB-231 cells, leading to mitochondria-mediated apoptosis. These results suggest that caspase-independent apoptosis may be induced by the generation of reactive oxygen species. In this study, we also demonstrated that 3-BrPA induces apoptosis through the downregulation of myeloid cell leukemia-1 (Mcl-1) in MDA-MB-231 breast cancer cells. The results of Mcl-1 knockdown indicate that Mcl-1 plays an important role in 3-BrPA-induced apoptosis. Further, the upregulation of Mcl-1 expression in 3-BrPA-treated MDA-MB-231 cells significantly increases cell viability. In addition, 3-BrPA treatment resulted in the downregulation of p-Akt, suggesting that 3-BrPA may downregulate Mcl-1 through the phosphoinositide-3-kinase/Akt pathway. These findings indicate that 3-BrPA induces apoptosis in breast cancer cells by downregulating Mcl-1 through the phosphoinositide-3-kinase/Akt signaling pathway.

Enzymatic glycosylation of nonbenzoquinone geldanamycin analogs via Bacillus UDP-glycosyltransferase.

Geldanamycin (GM) is a naturally occurring anticancer agent isolated from several strains of Streptomyces hygroscopicus. However, its potential clinical utility is compromised by its severe toxicity and poor water solubility. For this reason, considerable efforts are under way to make new derivatives that have both good clinical efficacy and high water solubility. On the other hand, glycosylation is often a step that improves the water solubility and/or biological activity in many natural products of biosynthesis. Here, we report the facile production of glucose-conjugated nonbenzoquinone GM analogs using the Bacillus UDP-glycosyltransferase BL-C. Five aglycon substrates containing nonbenzoquinone aromatic rings were chosen to validate the in vitro glycosylation reaction. Putative glucoside compounds were determined through the presence of a product peak(s) and were also verified using LC/MS analyses. Further, the chemical structures of new glucoside compounds 6 and 7 were elucidated using spectroscopy data. These glucoside compounds showed a dramatic improvement in water solubility compared with that of the original aglycon, nonbenzoquinone GM.

Biosynthesis of plant-specific phenylpropanoids by construction of an artificial biosynthetic pathway in Escherichia coli.

Biological synthesis of plant secondary metabolites has attracted increasing attention due to their proven or assumed beneficial properties and health-promoting effects. Phenylpropanoids are the precursors to a range of important plant metabolites such as the secondary metabolites belonging to the flavonoid/stilbenoid class of compounds. In this study, engineered Escherichia coli containing artificial phenylpropanoid biosynthetic pathways utilizing tyrosine as the initial precursor were established for production of plant-specific metabolites such as ferulic acid, naringenin, and resveratrol. The construction of the artificial pathway utilized tyrosine ammonia lyase and 4-coumarate 3-hydroxylase from Saccharothrix espanaensis, cinnamate/4-coumarate:coenzyme A ligase from Streptomyces coelicolor, caffeic acid O-methyltransferase and chalcone synthase from Arabidopsis thaliana, and stilbene synthase from Arachis hypogaea.

Bishonokiol A Induces Multiple Cell Death in Human Breast Cancer MCF-7 Cells.

OBJECTIVE: A dimeric neolignan, bishonokiol A (BHNKA) isolated from Magnolia grandiflora, significantly inhibits the proliferation of human breast cancer cells. However, the exact mechanism of BHNKA induced breast cancer cell death is unknown. In this study, we investigated the pharmacological mechanism underlying BHNKA induced MCF-7 cell death. METHODS: Cell viability measurement was performed by the MTT assay. Flow cytometry with PI staining, DAPI staining, and electron microscopy were used to analyze cellular death modes. In addition, western blotting, siRNA transfection, ATP assay, and fluorescence microscopy were used to determine the mechanism of BHNKA induced MCF-7 cell death. RESULTS: BHNKA induced cell death by apoptosis, necroptosis and autophagy at the same concentration and time in MCF-7 cells, and electron microscopy confirmed these results. The mechanism of BHNKA triggered apoptosis and autophagy in MCF-7 cells was primarily due to an increase in the Bax/Bcl-2 ratio and simultaneous up-regulation of LC3-II protein expression, respectively. BHNKA induced necroptosis by activation of the RIP1-RIP3-MLKL necroptosis cascade, up-regulation of cyclophilin D (CypD) protein expression to stimulate ROS generation. We further demonstrated that siRNA-mediated down-regulation of CypD protected against BHNKA induced cell death. CONCLUSIONS: These results suggest that BHNKA may be a potential lead compound for development as an anti-breast cancer agent for induction of multiple cell death pathways.