Drimane-Type Sesquiterpene Coumarins from Ferula gummosa Fruits Enhance Doxorubicin Uptake in Doxorubicin-Resistant Human Breast Cancer Cell Line.

Multidrug resistance (MDR) is the main cause of failure in the chemotherapy of cancer patients. The present study aimed to evaluate the effects of sesquiterpene coumarins of Ferula gummosa fruits on P-glycoprotein (P-gp)-mediated MDR. Drimane-type sesquiterpene coumarins from the fruits of F. gummosa were extracted with dichloromethane and subjected to column chromatography. The effects of the isolated compounds on P-gp-mediated MDR were evaluated in the breast cancer cell line MCF-7 which shows high resistance to doxoribicin (MCF-7/Dox). Phytochemical investigation of dichloromethane extract of F. gummosa fruits resulted in three sesquiterpene coumarins including conferone (1), mogoltacin (2), and feselol (3). The structures of these compounds were confirmed by 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy. Exposure of cells to conferone, mogoltacin, feselol, and verapamil (positive control) enhanced doxorubicin uptake by MCF-7/Dox cells. This effect was dose dependent, but varied with the structure of the chemical. At 25 µM, all the tested sesquiterpene coumarins restored at least 50% of the reference uptake (uptake by sensitive cells); but at 10 µM, their potency varied where conferone showed the highest potency and feselol showed the lowest potency. Conferone, mogoltacin, and feselol from F. gummosa suppress P-gp-mediated drug efflux in highly resistant human breast cancer cells.

Possible benefits of curcumin regimen in combination with taxane chemotherapy for hormone-refractory prostate cancer treatment.

Complementary and alternative therapies for neoplastic diseases treatment and prevention receive increasing attention from the medical community. Prostate cancer (PC) is the most frequently diagnosed malignancy and the second major cause of male death in industrialized countries. The chemopreventive properties and clinical safety of curcumin, a polyphenolic derivative, have already been established. However, curcumin regimen value in addition to conventional hormone refractory (HR) PC treatment remains largely unknown. This review article summarizes mechanisms by which curcumin may decrease HRPC aggressive proliferation and potentiate activity of taxane therapy. Our analysis suggests that curcumin alone has a therapeutic value in HRPC. In combination with a taxane agent, this compound may enhance cytotoxicity and retard PC cell resistance to taxane. As a consequence, a rationale is provided for considering the possible benefits of curcumin regimen in combination with taxane therapy in HRPC patients.

Phase I dose escalation trial of docetaxel plus curcumin in patients with advanced and metastatic breast cancer.

BACKGROUND: Since the improvement of chemotherapy with safe molecules is needed for a better efficacy without supplementary toxicity, we investigated the feasibility and tolerability of the combination of docetaxel and curcumin, a polyphenolic derivative extracted from Curcuma longa root. RESULTS: Fourteen patients were accrued in this open-label phase I trial. At the last dose level of curcumin, three dose-limiting toxicities were observed and two out of three patients at this dose level refused to continue treatment, leading us to define the maximal tolerated dose of curcumin at 8,000 mg/d. Eight patients out of 14 had measurable lesions according to RECIST criteria, with five PR and three SD. Some improvements as biological and clinical responses were observed in most patients. PATIENTS AND METHODS: Patients with advanced or metastatic breast cancer were eligible. Docetaxel (100 mg/m(2)) was administered as a 1 h i.v. infusion every 3 w on d 1 for six cycles. Curcumin was orally given from 500 mg/d for seven consecutive d by cycle (from d-4 to d+2) and escalated until a dose-limiting toxicity should occur. The primary endpoint of this study was to determine the maximal tolerated dose of the combination of dose-escalating curcumin and standard dose of docetaxel chemotherapy in advanced and metastatic breast cancer patients. Secondary objectives included toxicity, safety, vascular endothelial growth factor and tumor markers measurements and assessment of objective and clinical responses to the combination therapy. CONCLUSION: The recommended dose of curcumin is 6,000 mg/d for seven consecutive d every 3 w in combination with a standard dose of docetaxel. From the encouraging efficacy results, a comparative phase II trial of this regimen plus docetaxel versus docetaxel alone is ongoing in advanced and metastatic breast cancer patients.

Umbelliprenin from Ferula szowitsiana inhibits the growth of human M4Beu metastatic pigmented malignant melanoma cells through cell-cycle arrest in G1 and induction of caspase-dependent apoptosis.

Metastatic malignant melanoma have a bad prognosis (median survival: 6-8 months) mainly due to the development of lung, hepatic and brain metastases. In this study we have used the resazurin reduction test and FACS analysis to assess the cytostatic and cytotoxic effect of umbelliprenin from Ferula szowitsiana (Apiaceae) on human solid cancer cells and human primary fibroblasts. We have observed that the cell susceptibility to umbelliprenin decreases in the order M4Beu (metastatic pigmented malignant melanoma)>A549 (nonsmall cell lung carcinoma) approximately PC3 (androgen-resistant prostate carcinoma)>PA1 (ovary teratocarcinoma)>human primary fibroblasts approximately MCF7 (breast adenocarcinoma)>DLD1 (colon adenocarcinoma). M4Beu cell-proliferation is inhibited through cell-cycle arrest in G1 and induction of caspase-dependent apoptosis. The finding that the cytotoxic effect of umbelliprenin is markedly more pronounced in M4Beu cells than in primary fibroblasts, suggests a therapeutic margin. As M4Beu cell proliferation is more potently inhibited by umbelliprenin (IC50 12.3 microM) than by the citrus coumarin auraptene (7-geranyloxycoumarin, IC50 17.1 microM) previously reported capable of inhibiting the prevalence of lung metastasis in mice bearing B16BL6 murine melanoma, our data suggest that umbelliprenin orally administered and foods and folk medicines containing this coumarin, may afford protection against the development and early recurrence of malignant melanoma. In vivo investigations are needed to test these hypotheses.

The dietary flavones apigenin and luteolin impair smooth muscle cell migration and VEGF expression through inhibition of PDGFR-beta phosphorylation.

Platelet-derived growth factor (PDGF)-dependent recruitment of mural cells such as pericytes and smooth muscle cells plays a central role in the maturation and stabilization of newly formed vasculature during angiogenesis. In this work, we show that the dietary flavones apigenin and luteolin may interfere with this event through their inhibitory effect on PDGF-dependent phosphorylation of PDGF receptor beta (PDGFR-beta) in smooth muscle cells. Inhibition of PDGFR-beta activity by apigenin and luteolin occurred at low concentrations of the molecules and resulted in the inhibition of extracellular signal-regulated kinase and Akt phosphorylation triggered by PDGF, as well as in a marked reduction of the migratory and invasive properties of these cells. Apigenin and luteolin also strongly inhibit the PDGF-dependent increase in vascular endothelial growth factor (VEGF) mRNA levels and the secretion of VEGF by smooth muscle cells as well as vessel formation in the mouse Matrigel plug assay, suggesting that the inhibitory effects of both molecules on smooth muscle cell function result in impaired angiogenesis. Overall, these results identify apigenin and luteolin as dietary-derived inhibitors of PDGFR-beta activity and suggest that this inhibitory effect may contribute to the chemopreventive properties of these molecules.

Reversal of P-glycoprotein-mediated drug efflux by eudesmin from Haplophyllum perforatum and cytotoxicity pattern versus diphyllin, podophyllotoxin and etoposide.

The present study focuses on eudesmin (bicyclic lignan, 0.15 % of dry leaves) and diphyllin (arylnaphthalene lignan, 0.1 % of dry roots), both isolated from H. perforatum Kar. et Kir, a Rutaceae species endemic to Uzbekistan. We first compared their specificity for cancer cells with those of etoposide and podophyllotoxin by screening their cytotoxicity on 3 healthy cell-lines and 7 sensitive or resistant human solid cancer lines. We then tested their capacity to reverse P-glycoprotein-mediated multidrug resistance (MDR) by assaying dye and drug uptake in MDR1-transfected Madin-Darby canine kidney (MDCK-MDR1) and doxorubicine-resistant human breast carcinoma cells (MCF7/Dox). Eudesmin displays IC (50) values > 100 microM on all tested lines. Our data provide the first demonstration that this non-toxic lignan reverses Pgp-mediated drug efflux and supports the hypothesis that it may inhibit resistance mediated by MDR1 and MRP proteins. Even if its reversal activity is insufficient for clinical application, its capacity to accumulate [(3)H]-vinblastine in MDCK/MDR1 and MCF7/Dox cells suggests that eudesmin may positively affect the bioavailability and, thereby, the therapeutic potency of anticancer drugs in Pgp-overexpressing cells. Diphyllin exhibits IC (50) values ranging from 10 (- 6) to 10 (- 4) M. It is markedly less toxic than podophyllotoxin (IC (50) : 13 - 61 nM), but exhibits tumoricidal effects close to those of etoposide. Unfortunatly, it is 65-fold more toxic than etoposide on human primary fibroblasts. Consequently, it has no value as an anticancer drug. Its value as raw material for the hemisynthesis of anticancer drugs is discussed.

Conferone from Ferula schtschurowskiana enhances vinblastine cytotoxicity in MDCK-MDR1 cells by competitively inhibiting P-glycoprotein transport.

Overexpression of the protein transporter P-glycoprotein (Pgp, MDR1) at the cell surface is a major cause of multidrug resistance (MDR) and poor response to treatment in cancer chemotherapy and therapy for leishmaniasis. The present study shows that conferone, a sesquiterpene coumarin ether isolated for the first time from Ferula schtschurowskiana, endemic in Uzbekistan, enhances the cell toxicity of vinblastine (VBL) in MDR1-transfected Madin-Darby canine kidney (MDCK-MDR1) cells. Conferone presents the advantage to mediate this effect at safe concentrations. At 10 microM, it efficiently competes with the photoactivatable cyclosporin A analogue (SDZ 212 - 122) for the binding to Pgp and accumulates [3H]-VBL to a higher extent than cyclosporin A or cnidiadin. [3H]-VBL accumulation is dose-dependent and correlates with the inhibition of Pgp photolabeling affinity, supporting the hypothesis that conferone sensitizes MDCK-MDR1 cells to VBL by competitively inhibiting drug efflux. In MDCK-MDR1 cells, [3H]-VBL accumulation appears to be almost completely dependent on inhibition of Pgp transport. However, the strict specificity of conferone to this efflux pump has to be demonstrated in cell lines expressing other protein transporters. Collectively, our findings identify conferone as a powerful modulator of Pgp transport and a promising molecule for the treatment of MDR malignancies and leishmaniasis. Complementary in vitro and in vivo studies are, however, needed to assess the value of conferone as a reversal drug in human therapy. Considering its high affinity for Pgp, conferone may have an additional usefulness as a tool for the design or the (hemi)synthesis of agents probing Pgp. To our knowledge, this is the first report identifying sesquiterpene coumarins from Ferula as possible drug candidates for the reversion of MDR encoded by the MDR1 gene or the synthesis of agents probing Pgp.

Beef conjugated linoleic acid isomers reduce human cancer cell growth even when associated with other beef fatty acids.

Although many data are available concerning anticarcinogenic effects of industrial conjugated linoleic acid (CLA), few studies have reported the antitumour properties of CLA mixtures originating from ruminant products. The aim of the present study was to investigate the in vitro antiproliferative effects of beef CLA mixtures on breast, lung, colon, melanoma and ovarian human cancer cell lines. For this purpose, four fatty acid (FA) extracts prepared from beef lipid and varying in their CLA composition, their corresponding purified CLA-enriched fractions, and mixtures of pure synthetic CLA, the composition of which reproduced that of the four selected beef samples, were tested on cancer cell lines. Cancer cells were exposed for 48 h to medium containing 100 microm-FA and their proliferation was determined by quantifying cellular DNA content (Hoechst 33342 dye). Compared with cells incubated without FA, the number of cancer cells was reduced from 25 to 67 % (P<0.0001) following FA treatment. Antiproliferative effects of CLA mixtures varied in magnitude according to the source of FA, the CLA composition and the cell lines. CLA mixtures naturally present in beef inhibited the proliferation of human cancer cell lines, a high content in cis-trans isomers allowing the most important antiproliferative effect. Beef total FA exhibited a greater growth-inhibitory activity than their corresponding CLA-enriched fractions. These results suggested that either beef FA other than beef CLA could possess antiproliferative properties and/or the existence of complementary effects of non-conjugated FA and CLA, which could favour the antiproliferative properties of beef total FA.

In vitro activity of hederacolchisid A1 compared with other saponins from Hedera colchica against proliferation of human carcinoma and melanoma cells.

Hederacolchisid A1, a new oleanolic acid monodesmoside, isolated from Hedera colchica K. Koch, an ivy species endemic in Georgia, was evaluated in vitro for antiproliferative activity on cancer cells versus normal cells in comparison to cisplatin. Investigations were made on six human cell lines (colon adenocarcinoma DLD-1, ovarian teratocarcinoma PA 1, lung carcinoma A 549, breast adenocarcinoma MCF7, prostatic adenocarcinoma PC 3 and malignant melanoma M4 Beu) versus normal human fibroblasts, by assaying both cellular metabolic activity (RTT test) and DNA content in living cells (test with Hoechst 33,342) after 48 h continuous contact. Results demonstrated the strong cytotoxicity of hederacolchisid A 1 on all cancer cells (IC50 from 4.5 to 12 microM). The antiproliferative effects on malignant melanoma M4 Beu (IC50 ca 4.5 microM) versus normal cells (IC50 ca 7.5 microM) suggests that, despite a lack of specificity for cancer cells, hederacolchisid A1 has potential anti-tumor applications. Comparison of the cytotoxicity of hederacolchisid A 1 with that of five other saponins from H. colchica, offers some new information about structure-activity relationships. It was observed that i) for a same sugar sequence, monodesmosides with oleanolic acid as aglycone exhibit higher cytotoxicity than those containing hederagenin, ii) the sugar sequence O-alpha-L-rhamnopyranosyl (1 --> 2)-alpha-L-arabinopyranoside at C3 induces strong cytotoxicity and might be identified as a basic sequence for anti-tumor activity of oleanolic acid monodesmosides. iii) a complementary glucopyranosyl moiety branched at C1 of arabinose increases the cytotoxicity against malignant melanoma M4 Beu, prostatic adenocarcinoma PC 3 and normal fibroblasts in a different manner for each type of monodesmoside. A slight increase whose amplitude was quite similar on cancers and normal cells, was observed with oleanolic acid monodesmoside. This increase was much higher with hederagenin monodesmoside and markedly elevated in normal cells than in cancer cells.