金荞麦提取物抑制肿瘤细胞侵袭、转移和HT-1080细胞产生Ⅳ型胶原酶的研究

目的探讨金荞麦提取物对肿瘤细胞侵袭和转移的影响。方法以人工重组基底膜及小鼠黑色素瘤高转移株自发性肺转移模型观察了金荞麦提取物对Ｂ１６－ＢＬ６细胞的体外抗侵袭活性和体内抗转移作用；用聚丙烯酰胺凝胶电泳法进一步观察了其对人纤维肉瘤ＨＴ－１０８０细胞Ⅳ型胶原酶的产生及活性的影响；同时用ＷＳＴ法观察了该药的细胞毒性。结果金荞麦提取物在１００ｍｇＬ－１剂量下能明显抑制Ｂ１６－ＢＬ６细胞侵袭；在２００ｍｇｋｇ－１剂量下能有效抑制Ｂ１６－ＢＬ６黑色素瘤细胞在Ｃ５７／ＢＬ６小鼠体内自发性肺转移。该药对Ｂ１６－ＢＬ６和ＨＴ－１０８０细胞无明显细胞毒作用。该药能抑制ＨＴ－１０８０细胞Ⅳ胶原酶的产生，但对酶的活性无明显影响。结论金荞麦提取物具有明显的抗癌侵袭和转移的作用。     

Ginsenoside 20(S)-protopanaxadiol inhibits the proliferation and invasion of human fibrosarcoma HT1080 cells

Ginsenoside 20(S)-protopanaxadiol, one of metabolites of ginseng saponins, has been well characterized to possess the pleiotropic anticancer capabilities in several cancer cell lines. The object of this study was to investigate the effects of ginsenoside 20(S)-protopanaxadiol on the invasion in vitro and the expression of matrix metalloproteinase-2 in human fibrosarcoma HT1080 cells in absence of cytotoxicity. Our results showed that ginsenoside 20(S)-protopanaxadiol exerted a concentration-dependent inhibitory effect on the proliferation of HT1080 cells (IC50 was 76.78+/-2.24 microM, 48 hr). Treatment with 20(S)-protopanaxadiol significantly declined the invasive capacity of HT1080 cells compared to the control cells (P<0.01) in the in vitro invasion assay. Further analysis with gelatin zymography and western blotting revealed that both the activity and the expression of matrix metalloproteinase-2 decreased dramatically in a concentration-dependent manner (P<0.01). Taken together, these results indicated that ginsenoside 20(S)-protopanaxadiol is able to inhibit the invasiveness of HT1080 cells significantly in vitro and this action may be primarily due to down-regulating the expression of matrix metalloproteinase-2. Ginsenoside 20(S)-protopanaxadiol, a metabolite of ginseng, may be applied as a potential therapeutic agent in the prevention and treatment of cancer.     

Reversing hypoxic cell chemoresistance in vitro using genetic and small molecule approaches targeting hypoxia inducible factor-1

The resistance of hypoxic cells to conventional chemotherapy is well documented. Using both adenovirus-mediated gene delivery and small molecules targeting hypoxia-inducible factor-1 (HIF-1), we evaluated the impact of HIF-1 inhibition on the sensitivity of hypoxic tumor cells to etoposide. The genetic therapy exploited a truncated HIF-1alpha protein that acts as a dominant-negative HIF-1alpha (HIF-1alpha-no-TAD). Its functionality was validated in six human tumor cell lines using HIF-1 reporter assays. An EGFP-fused protein demonstrated that the dominant-negative HIF-1alpha was nucleus-localized and constitutively expressed irrespective of oxygen tension. The small molecules studied were quinocarmycin monocitrate (KW2152), its analog 7-cyanoquinocarcinol (DX-52-1), and topotecan. DX-52-1 and topotecan have been previously established as HIF-1 inhibitors. HT1080 and HCT116 cells were treated with either AdHIF-1alpha-no-TAD or nontoxic concentrations (0.1 microM; 相似文献   

Two purified and characterized phospholipases A2 from Cerastes cerastes venom, that inhibit cancerous cell adhesion and migration

Two non-toxic PLA2s were purified to homogeneity from Cerastes cerastes Tunisian snake venom. The purification process employed gel filtration on Sephadex G-75 followed by C18 reverse phase high-pressure liquid chromatography. These two acidic enzymes, namely CC-PLA2-1 and CC-PLA2-2, have a molecular weight of 13,737.52 and 13,705.63 Da, respectively. These two PLA2 are the first reported glycosylated phospholipases A2 purified from snake venom. The rates of glycosylation are 2.5% and 0.5% (w/w), respectively. Specific activities of 1800 U/mg and 2400 U/mg for CC-PLA2-1 and CC-PLA2-2, respectively, were measured at optimal conditions. CC-PLA2-1 and CC-PLA2-2 strongly inhibited coagulation. They also exhibited a marked dose-dependent inhibitory effect on platelet aggregation induced by ADP and arachidonic acid in platelet-rich plasma. Interestingly, CC-PLA2-1 and CC-PLA2-2 inhibited in a dose-dependent manner adhesion of IGR39 melanoma and HT1080 fibrosarcoma cells to fibrinogen and fibronectin. Furthermore, both CC-PLA2-1 and CC-PLA2-2 abolished HT1080 cell migration towards fibrinogen and fibronectin. This activity is reported for the first time for PLA2 enzymes.     

XR5967, a novel modulator of plasminogen activator inhibitor-1 activity, suppresses tumor cell invasion and angiogenesis in vitro

Recent reports suggest that elevated levels of plasminogen activator inhibitor (PAI)-1 may contribute to tumor progression. We have recently shown that antibodies to PAI-1 block the invasive and migratory potential of human fibrosarcoma cells and suppress angiogenesis in vitro. Here we report the in vitro evaluation of a low-molecular-weight modulator of PAI-1, XR5967, on invasion, migration and angiogenesis. XR5967, a diketopiperazine, dose-dependently inhibited the activity of human and murine PAI-1, towards urokinase plasminogen activator (uPA), with IC50 values of 800 nM and 8.3 microM, respectively. This was confirmed by SDS-PAGE, revealing that XR5967 inhibited complex formation between PAI-1 and uPA. This suppression may be caused by XR5967 promoting insertion of the reactive center loop within PAI-1. XR5967 dose-dependently inhibited the invasion of human HT1080 fibrosarcoma cells through Matrigel. Their invasion was reduced by 57% (p<0.001) at 5 microM. HT1080 cell migration was inhibited in a similar manner, indicating that PAI-1 may play an additional role in invasion, which is distinct to its role in the regulation of proteolysis. The potential of XR5967 to inhibit the invasion/migration of human endothelial cells was investigated in an in vitro model of angiogenesis. In this model XR5967 reduced tubule formation by 77% at 5 microM (p<0.001), highlighting a crucial role for PAI-1 in angiogenesis. These data stress the importance of a balanced proteolysis in the processes of invasion, migration and angiogenesis. Our results support the clinical findings and indicate that modulation of PAI-1 activity, with low-molecular-weight inhibitor of PAI-1 activity, may be of therapeutic benefit for the treatment of cancer.     

Bisphosphonates inhibit stromelysin-1 (MMP-3), matrix metalloelastase (MMP-12), collagenase-3 (MMP-13) and enamelysin (MMP-20), but not urokinase-type plasminogen activator, and diminish invasion and migration of human malignant and endothelial cell lines

Bisphosphonates (clodronate, alendronate, pamidronate and zoledronate) at therapeutically attainable non-cytotoxic concentrations inhibited MMP-3, -12, -13 and -20 as well as MMP-1, -2, -8 and -9, but not urokinase-type plasminogen activator (uPA), a serine proteinase and a pro-MMP activator. Dose-dependent inhibition was shown by three independent MMP assays. The inhibition was reduced in the presence of an increased concentration of Ca(2+) when compared to physiologic Ca(2+) concentration. Alendronate inhibited the in vitro invasion (Matrigel) of human HT1080 fibrosarcoma and C8161 melanoma cells, and the random migration of these malignant and endothelial cell lines capable of expressing MMPs and uPA. The concentration of alendronate required to inhibit 50% of the activity (IC(50)=40-70 microM) of MMPs corresponded to the IC(50) of down-regulation of in vitro invasion and migration. The ability of bisphosphonates to down-regulate the in vitro invasion and random migration was comparable or slightly better in relation to the selective gelatinase inhibitor CTTHWGFTLC peptide. Alendronate but not CTTHWGFTLC peptide promoted the adhesion of HT1080 fibrosarcoma and C8161 melanoma cell lines on fibronectin. Bisphosphonates are broad-spectrum MMP inhibitors and this inhibition involves cation chelation. Bisphosphonates further exert antimetastatic, anti-invasive and cell adhesion-promoting properties, which may prevent metastases not only into hard tissues but also to soft tissues.     

Resveratrol glucuronides as the metabolites of resveratrol in humans: characterization, synthesis, and anti-HIV activity

Resveratrol is a natural product with diverse biological activities. We have previously reported that resveratrol possesses potent synergistic inhibitory activity against human immunodeficiency virus (HIV)-1 infection in combination with nucleoside analogs (Heredia et al. 2000. J Acquir Immune Defic Syndr 25:246-255). As a part of our program in developing resveratrol as a component for anti-HIV chemotherapy, we describe in this article the characterization, chemical synthesis, and biological effects of the human metabolites of resveratrol. We found that resveratrol was metabolized in humans into two metabolites, which were characterized as resveratrol-3-O- and 4'-O-glucuronides. For further biological studies, we reported two simple, alternative methods for the synthesis of the metabolites. The cytotoxic and antiviral activities of resveratrol and its metabolites were compared in cell culture experiments using human peripheral blood mononuclear cells. Whereas resveratrol was cytotoxic at > or =30 microM, no cytotoxicity was observed for the metabolites at concentrations as high as 300 microM. However, resveratrol showed strong synergistic anti-HIV activity with didanosine at 10 microM, but no synergistic effects were observed for either of the metabolites at up to 300 microM. Nevertheless, the in vitro activity of the metabolites (resveratrol glucuronides) may not necessarily reflect their in vivo function, given the fact that the ubiquitously existing human beta-glucuronidase could convert the metabolites back to resveratrol locally or systematically in vivo. The present studies have implications for future development of resveratrol and/or its derivatives as a chemotherapeutic agent.     

The inhibitory activities of 480156-S and its related compounds on prostaglandin synthetase

The inhibitory activities of 2-arylpropionic acids on prostaglandin synthetase were in the order of: Flurbiprofen (ID50, 0.10 microM) greater than Indomethacin (0.28 microM) greater than Ketoprofen (0.34 microM) greater than Naproxen (2.5 microM) greater than 480156-S (6.0 microM) greater than Ibuprofen (6.5 microM) greater than Benoxaprofen (47.9 microM). The S(+)-enantiomers had 15-300 times higher inhibitory activities than the corresponding R(-)-enantiomers. 2-Phenylpropionic acid and the metabolites of 480156-S (M-I, M-II and M-III) did not show any inhibitory activity on prostaglandin synthetase. Therefore, the presence of a hydrophobic substituent group, such as thiazolyloxy, on the benzene ring of 2-phenylpropionic acid is essential for the inhibition of prostaglandin synthetase, and the compound with the para substituent showed the highest inhibitory activity. The substituent groups also influence the inhibitory activity. Thiazolylamino (compound No. 320) and 3-methyl-4-thiazolin-2-ylidenamino (229) showed higher inhibitory activity than thiazolyloxy (156), and N-methyl-N-thiazol-2-ylamino (185) showed the lowest activity. The placement of a fluoro atom at the 3-position or two chloro atoms at the 3,5-positions of the benzene ring increased the inhibitory activity of the prostaglandin synthetase, but this did not necessarily occur with the placement of a chloro atom at the 3-position. Inhibitory activities of 480156-S-related compounds against prostaglandin synthetase showed a good correlation with their anti-inflammatory activities, but did not correlate with their analgesic activities.     

New aureothin derivative, alloaureothin, from Streptomyces sp. MM23

A new polypropionate alloaureothin (1) possessing a nitro group, together with a known polypropionate aureothin (2), was isolated from mycelium of Streptomyces sp. MM23. The structure was determined on the basis of spectroscopic data. 1 exhibited growth inhibitory effect against human fibrosarcoma HT1080 cells with an IC50 value of 30 microM.     

Chemical modification of alisol B 23-acetate and their cytotoxic activity

The twelve-protostane analogues were synthesized from alisol B 23-acetate and assessed for their in vitro antitumor activity against six different human and murine tumor cell lines. Of the compounds synthesized, 23S-acetoxy-24R(25)-epoxy-11beta,23S-dihydroxyprotost-13(17)-en-3-hydroxyimine (12) exhibited significant cytotoxic activities against A549, SK-OV3, B16-F10, and HT1080 tumor cells with ED50 values of 10.0, 8.7, 5.2, and 3.1 microg/ml, respectively. Furthermore, 23S-acetoxy-13(17),24R(25)-diepoxy-11beta-hydroxyprotost-3-one (5), 13(17),24R(25)-diepoxy-11beta,23S-dihydroxyprotostan-3-one (6), 24R,25-epoxy-11beta,23S-dihydroxyprotost-13(17)-en-3-one (7), and 11beta,23S,24R,25-tetrahydroxyprotost-13(17)-en-3-one (9) showed moderate cytotoxic activities against B16-F10 and HT1080 tumor cells. These results mean that a hydroxyimino group at C-3 position in the protostane-type terpene enhances cytotoxic activity.     

Effect of 15-lipoxygenase metabolites, 15-(S)-HPETE and 15-(S)-HETE on chronic myelogenous leukemia cell line K-562: reactive oxygen species (ROS) mediate caspase-dependent apoptosis

Growth inhibitory effects of 15-lipoxygenase-1 [13-(S)-HPODE and 13-(S)-HODE] and 15-lipoxygenase-2 [15-(S)-HPETE and 15-(S)-HETE] (15-LOX-1 and LOX-2) metabolites and the underlying mechanisms were studied on chronic myeloid leukemia cell line (K-562). The hydroperoxy metabolites, 15-(S)-HPETE and 13-(S)-HPODE rapidly inhibited the growth of K-562 cells by 3h with IC(50) values, 10 and 15microM, respectively. In contrast, the hydroxy metabolite of 15-LOX-2, 15-(S)-HETE, showed 50% inhibition only at 40microM by 6h and 13-(S)-HODE, hydroxy metabolite of 15-LOX-1, showed no significant effect up to 160microM. The cells exposed to 10microM of 15-(S)-HPETE and 40microM of 15-(S)-HETE showed typical apoptotic features like release of cytochrome c, caspase-3 activation and PARP-1 (poly(ADP) ribose polymerase-1) cleavage. A flow cytometry based DCFH-DA analysis and inhibitory studies with DPI, a pharmacological inhibitor of NADPH oxidase, NAC (N-acetyl cysteine) and GSH revealed that NADPH oxidase-mediated generation of ROS is responsible for caspase-3 activation and subsequent induction of apoptosis in the K-562 cell line.     

Inorganic arsenic compounds and methylated metabolites induce morphological transformation in two-stage BALB/c 3T3 cell assay and inhibit metabolic cooperation in V79 cell assay.

We have performed two-stage transformation assay using BALB/c 3T3 cells to determine initiating and promoting activities of disodium arsenate, sodium arsenite, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). Treatment with these arsenic compounds at the initiating stage induced significant numbers of transformed foci when cells were post-treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). Disodium arsenate was active at the concentrations of 15-30 microM, sodium arsenite 5-20 microM, and DMAA 1-2 mM. MMAA required 10 mM to induce cell transformation. The concentrations of these compounds (except DMAA) that induced transformation were highly growth-inhibitory (more than 50%). DMAA induced transformation foci at growth inhibition levels of 66 to 84%. In experiments on promoting activity, cells pretreated with a sub-threshold dose of 20-methylcholanthrene (MCA, 0.2 microg/ml) or sodium arsenite (10 microM) were used. Transformation was enhanced by post-treatment with disodium arsenate (1-10 microM), sodium arsenite (0.5-2 microM), and MMAA (200-1000 microM), but not with DMAA. Studies of gap junctional intercellular communication using the V79 cell metabolic cooperation assay showed that the arsenic compounds (except DMAA) exhibited inhibitory activity. Thus, most arsenicals were shown to have not only initiating activity, but also promoting activity. In addition, inorganic arsenicals, especially trivalent sodium arsenite, were more active than organic ones and exhibited promoting activity at one-order of magnitude lower than initiating activity. These results suggest that from the viewpoint of human hazard, more attention should be paid to the tumor promoting activity of inorganic arsenic compounds.     

Effect of the nature of the spacer on gene transfer efficacies of novel thiocholesterol derived gemini lipids in different cell lines: a structure-activity investigation

A structure-activity investigation was undertaken to see the effect of the nature of the spacer on the gene transfection efficacies of thiocholesterol-derived cationic gemini lipids possessing disulfide linkage between the cationic headgroup and the thiocholesterol moiety. Three gemini cationic lipids possessing hydrophobic flexible (-(CH 2) 5-; 1), hydrophobic rigid (-C 6H 4-; 2), and hydrophilic flexible (-CH 2-CH 2-O-CH 2-CH 2-; 3) spacer segments were synthesized. In HeLa cells, lipid formulations 1 and 2 were found to be more effective as compared to lipid 3 formulation. In HT1080 cell line, the order of transfectability was 3 > 1 > 2. Transfection studies in HeLa and HT1080 cell line also showed 40-50% transfection efficacy in the presence of 10% serum conditions. These formulations were also able to transfect gene across difficult cells like HaCaT. Cytotoxic studies showed the nontoxic nature of these lipid-DNA complexes at different N/P ratios used for transfection studies.     

Inhibitory effects of azelastine and its metabolites on drug oxidation catalyzed by human cytochrome P-450 enzymes.

Azelastine, an antiallergy and antiasthmatic drug, has been reported to be metabolized mainly to desmethylazelastine and 6-hydroxyazelastine in mammals. In the present study, the inhibitory effects of azelastine and its two metabolites on human cytochrome P-450 (CYP) isoform-dependent reactions were investigated to predict the drug interactions of azelastine using microsomes from human B-lymphoblast cells expressing CYP. The specific activities for human CYP isoforms included: 7-ethoxyresorufin O-deethylation (CYP1A1), phenacetin O-deethylation (CYP1A2), coumarin 7-hydroxylation (CYP2A6), 7-benzyloxyresorufin O-dealkylation (CYP2B6), S-warfarin 7-hydroxylation (CYP2C9), S-mephenytoin 4'-hydroxylation (CYP2C19), bufuralol 1'-hydroxylation (CYP2D6), chlorzoxazone 6-hydroxylation (CYP2E1), and testosterone 6beta-hydroxylation (CYP3A4). In almost all the activities, desmethylazelastine exhibited stronger inhibition than azelastine and 6-hydroxyazelastine. Desmethylazelastine, but not azelastine and 6-hydroxyazelastine, uncompetitively inhibited CYP2B6 activity (Ki = 32.6 +/- 4.8 microM). Azelastine, desmethylazelastine, and 6-hydroxyazelastine competitively inhibited CYP2C9 activity (Ki = 13. 9 +/- 1.8, 15.0 +/- 3.1, and 17.0 +/- 4.1 microM, respectively), CYP2C19 activity (Ki = 21.9 +/- 2.2, 7.3 +/- 1.6, and 9.3 +/- 1.6 microM, respectively), and CYP2D6 activity (Ki = 1.2 +/- 0.1, 1.5 +/- 0.2, and 3.0 +/- 0.5 microM, respectively). Azelastine and desmethylazelastine competitively inhibited CYP3A4 activity (Ki = 23. 7 +/- 4.6 and 13.2 +/- 2.3 microM). 6-Hydroxyazelastine interfered with the determination of testosterone 6beta-hydroxylation by HPLC. CYP1A2, CYP2A6, and CYP2E1 activities were not significantly inhibited by azelastine and the two metabolites. Among the human CYPs tested, the inhibitory effects of azelastine and its two metabolites were the most potent on human CYP2D6. In consideration of the Ki values and the concentration of azelastine and desmethylazelastine in human livers after chronic oral administration of azelastine, the possibility of in vivo drug interaction of azelastine and other drugs that are mainly metabolized by CYP2D6 was suggested although it might not cause critical side effects. The inhibition of CYP2C9, CYP2C19, and CYP3A4 activity by azelastine and its two metabolites might be clinically insignificant.     

Inhibition of T cell mitogenesis by nitrofurans

A group of nitrofurans (5-nitro-2-furaldehyde, nifuroxime, nitrofurazone, nitrofurantoin, 5-nitro-2-furoic acid and 2-nitrofuran) were evaluated for inhibition of mitogenesis (DNA synthesis) in human peripheral blood T cells. T cells, either triggered by phorbol myristate acetate (PMA) or in the presence of accessory cells, were activated with a specified mitogen [phytohemagglutin (PHA), concanavalin A (ConA), or anti-CD3] and the amount of tritiated thymidine incorporated into DNA was determined. The results obtained indicate that nitrofurans inhibit mitogenesis irrespective of activator. 5-Nitro-2-furaldehyde was much more inhibitory than the other compounds, while 2-nitrofuran was less inhibitory. When the aldehyde group (5-nitro-2-furaldehyde) was replaced by a carboxyl group (5-nitro-2-furoic acid), the inhibitory activity was also reduced greatly. These results show that while the nitro group alone confers inhibitory activity to the furan ring, the group at the 2 position is crucial. In general, the mitogenic response of purified T cells (lacking accessory cells) triggered by PMA (phorbol ester) was inhibited less than that of the T cell-accessory cell system. With the latter, 50% inhibition of T cell mitogenesis was achieved by nifuroxime, nitrofurazone, and nitrofurantoin at 45-51 and 34-39 microM with PHA and ConA respectively. When purified T cells were used, the values were 71-85 and 55-60 microM respectively. For a given drug concentration, mitogenesis was more inhibited when induced by ConA or anti-CD3 than by PHA. The importance of using a single cell system (purified T cells) was emphasized by the interesting finding that only this system showed enhancement of mitogenesis, up to 35-40% at low drug levels. With the exception of the nitrofuraldehyde, the nitrofurans at strongly inhibitory levels were only moderately cytotoxic, exhibiting 62-85% cell survival after exposure to drug for 68 hr. Our results suggest that nitrofurans inhibit T cell mitogenesis by a relatively non-toxic mechanism; these results are comparable to those obtained for mammalian cells under aerobic conditions.     

Ginseng intestinal bacterial metabolite IH901 as a new anti-metastatic agent

Anti-metastatic activities of IH901, an intestinal bacterial metabolic derivative formed from Ginseng protopanaxadiol saponins, was determinedin vitro andin vivo. Underin vitro conditions, IH901 inhibited the migration of bovine aortic endothelial cells 25 times stronger than suramin and suppressed the invasion of HT1080 human fibrosarcoma cells into reconstituted basement membrane components of Matrigel 1000 times stronger than RGDS peptide. IH901 also showed inhibitory effect on type-IV collagenase secretion from HT1080 cells and platelet aggregation. When the anti-metastatic activity of IH901 was evaluated in comparison with that of 5-FU using a spontaneous lung metastatic model of Lewis lung carcinoma, the administration of IH901 (10 mg/kg p. o.) to tumor-bearing mice led to a significant decrease in lung metastasis (43% of untreated control), which was slightly more effective than that obtained with 5-FU (56% of control). Thus, IH901 seems to exhibit its anti-metastatic activity partly through the inhibition of tumor invasion which results from the blockade of type IV collagenase secretion and also through anti-platelet and anti-angiogenic activities.     

In vitro and in vivo growth inhibition and G1 arrest in human cancer cell lines by diaminophenyladamantane derivatives

We describe the discovery of a novel series of anticancer adamantane derivatives which induce G1 arrest in Colo 205 and HT 29 colon cancer cells. Seven adamantane derivatives were screened for their activity in vitro against 60 human cancer cell lines in the National Cancer Institute (NCI)'s Anticancer Drug Screen system. The relationships between structure and in vitro anticancer activity are discussed. 1,3-Bis(4-(4-amino-3-hydroxyphenoxy)phenyl)adamantane (1,3-DPA/OH/NH2) and 2,2-bis(4-(4-amino-3-hydroxyphenoxy)phenyl)adamantane (DPA) exhibited strong growth inhibitory on anticancer activities in vitro. The IC50s of 1,3-DPA/OH/NH2 (NSC-706835) and DPA (NSC-706832) were found to be < 3 microM against 45 (85%) and 48 (91%) cell lines, respectively. 2,2-Substituted adamantane derivatives exhibited stronger growth inhibition on anticancer activities in vitro than the corresponding 1,3-substituted analogs. Very strong growth inhibition of 2,2-bis(4-aminophenyl)adamantane (NSC-711117) was observed against two colon cancer lines (HT-29 and KM-12), one CNS cancer line (SF-295) and one breast cancer line (NCI/ADR-RES) with IC50 < 1.0 microM, i.e. 0.1, 0.01, 0.059 and 0.079 microM, respectively. In addition, we also examined the in vitro and in vivo effects of DPA on three human colon cancer cells. DPA-treated Colo 205 and HT-29 cells were arrested at G0/G1 as analyzed by flow cytometric analysis. The DPA-induced cell growth inhibition was irreversible after removal of DPA. The in vivo effect of tumor growth suppression by DPA was also observed on colon Colo 205 xenografts. No acute toxicity was observed after an i.p. challenge of DPA in ICR nude mice weekly. These results suggest that DPA appears to be a new potentially less toxic modality of cancer therapy.     

Inhibitory effect of magnolol and honokiol from Magnolia obovata on human fibrosarcoma HT-1080. Invasiveness in vitro.

We investigated the inhibitory effect of Magnolia obovata Thunb. bark ethanol extracts on human fibrosarcoma HT-1080 cells invasion in a reconstituted basement membrane [Matrigel (MG)]. We found that the effective components of the bark ethanol extracts were magnolol and honokiol, two biphenyl compounds. The extracts, magnolol and honokiol, did not affect HT-1080 cells adhesion to MG, but did inhibit HT-1080 cells migration at a high concentration (100 microM). HT-1080 cells secrete matrix metalloproteinase (MMP)-9, which degrades the extracellular matrix as a part of the invasive process. Magnolol and honokiol inhibited the activity of MMP-9, which may have been responsible, in part, for the inhibition of tumor cell invasiveness.     

Effect of Epilobium angustifolium L. extracts and polyphenols on cell proliferation and neutral endopeptidase activity in selected cell lines

The ability of Epilobium extracts and polyphenols to induce neutral endopeptidase (NEP) activity and to inhibit the proliferation in cell lines with high NEP expression (SK-N-SH) and with low NEP expression (PC-3) was investigated. Epilobium extracts enhanced in a dose-depend manner NEP activity in both cell lines with additional inhibition of cell proliferation. The sensitivity of cells depended on basal enzyme activity. SK-N-SK cells were much more sensitive than PC-3 cells. Oenothein B enhanced NEP activity at a concentration of 5-40 microM while quercetin-3-glucuronide and quercetin-3-O-(6"-gal-loyl) galactoside showed slight or no activity at a concentration of 100 microM. The comparison of activities of the extracts with oenothein B, a dimeric macrocyclic ellagitannin, suggests that the latter is mostly responsible for the observed effects. Taking into account the role of NEP in the homeostasis of signalling peptides, Epilobium angustifolium extracts may be a potential herbal remedy in diseases connected with the disturbed metabolism of signaling peptides caused by an unbalanced neutral endopeptidase activity.