Synthesis, evaluation and proteomic analysis of PROTAC based on parthenolide / 药学学报

As a natural product with a long history of medicinal use, parthenolide has aroused great interest of chemists and biologists. Existing studies have shown that it has anti-inflammatory, antitumor and other pharmacological activities, and also revealed its action on NF-κB signaling pathway, DNMT1 enzyme and Wnt/β-catenin signaling pathway. But its biological targets remain to be elucidated systematically. Proteolysis Targeting Chimeras (PROTAC) provides a new strategy for target discovery of natural products, which can be used to explore the panorama of protein changes in cells through proteomic investigation, so as to analyze their potential targets. Based on this idea, current study designed and synthesized 20 parthenolide-derived degraders. After measured their antitumor activity in vitro, selected compounds were carried out the proteomic experiment. Finally, 139 down-regulated differentially expressed proteins were identified and the discovery of parthenolide interacting protein was preliminarily explored.

The mechanism of parthenolide strengthen vorinostat on inhibiting the proliferation of A549 non-small cell lung cancer cells / 药学学报

This research explored the synergistic effects and the mechanism of parthenolide (PTL) and vorinostat (suberoylanilide hydroxamic acid, SAHA) on the proliferation of A549 non-small cell lung cancer cells. The combination effect of PTL and SAHA was detected by cell counting kit-8 (CCK-8) and colony formation assays. Scratch test was performed to detect cell migration. Annexin V-fluorescein isothiocyanate isomer/propidium iodide (FITC/PI) flow cytometry and Western blot analyses were used to determine cell apoptosis and its mechanism. The results showed that combination of PTL and SAHA inhibited the proliferation and migration of A549 with a synergistic effect compared to the single-drug groups. The combination of PTL and SAHA had synergistic effect to induce cell apoptosis by regulating p53 and c-myc pathways, and affected the expression levels of poly ADP-ribose polymerase (PARP), cysteinyl aspartate specific proteinase (caspase)-9, and caspase-3. Taken together, this study shows that combination of PTL and SAHA has synergistic effect, induces cell apoptosis and inhibits A549 proliferation, which is likely to be a novel strategy for the treatment of non-small cell lung cancer.

Effect of parthenolide on proliferation and migration of MCF-7 breast cancer cells by targeting the c-myc G-quadruplex / 药学学报

This research investigated the effect of parthenolide on the proliferation and migration of human breast cancer cells and explored the molecular mechanism of that effect. Surface plasmon resonance and fluorescence resonance energy transfer melting were used to detect the binding and stabilizing ability of PTL and G-quadruplex. MTT assays were used to determine the effect of PTL on the proliferation of MCF-7 breast cancer cells. A wound healing assay was performed to detect the migration of MCF-7. The results indicate that PTL shows good binding and stabilizing activities with c-myc G-quadruplex with a KD = 13.1 μmol·L-1. PTL inhibited the proliferation of MCF-7 cells with an IC50 of 21.3 μmol·L-1 (24 h), 14.5 μmol·L-1 (48 h) and 9.1 μmol·L-1 (72 h). PTL inhibited MCF-7 breast cancer cell proliferation and migration and down-regulated the transcription and expression level of c-myc by targeting G-quadruplex.

Induction of p450 enzymes by derivative of parthenolide / 中草药

Objective: In this study, primary cultured human hepatocytes were used to study the induction of P450 enzyme by the sesquiterpene lactone derivative ACT001, which provided reference for the clinical use of ACT001. Methods Three batches of frozen primary human hepatocytes were inoculated and cultured, and CYP1A2, CYP2B6 and CYP3A4 were induced by ACT001. Real-time fluorescence quantitative PCR was used to determine the mRNA expression level of P450 enzyme, and the activity of P450 enzyme was determined by LC-MS/MS method. Results The expression level of P450 enzyme mRNA and the activity of P450 enzyme showed that the P450 enzyme induction model was successfully established. Compared with the control group, the CYP1A2 mRNA expression level and enzyme activity of ACT001 1 μmol/L and 6 μmol/L group showed no significant changes. The mRNA expression level of CYP1A2 in ACT001 30 μmol/L group was significantly decreased, and the enzyme activity was decreased, but not as significantly as that of mRNA. With the increase of ACT001 concentration, the expression level of CYP2B6 mRNA was gradually increased. Compared with the control group, the expression level of CYP2B6 mRNA in the ACT001 group at 30 μmol/L was significantly increased, which was seven times higher than that in the control group, and the increase of enzyme activity was four times higher than that in the control group, which was 40% higher than that in the phenobarbital sodium induction multiple. Compared with the control group, the CYP3A4 mRNA expression level of cells in the ACT001 1 μmol/L group was significantly increased, which was four times higher than that of the control group, but did not reach 40% of the positive inducer rifampicin, and the CYP3A4 mRNA expression level was decreased gradually with the increase of ACT001 concentration. At the same time, there was no significant increase in CYP3A4 enzyme activity after ACT001 administration at different concentrations, which was less than two times of that in the control group. Conclusion The data indicated that ACT001 had no induction potential for CYP1A2 and CYP3A4, and had potential for CYP2B6 induction. In combination with CYP2B6 substrates, it should be avoided in clinical combination therapy to reduce adverse reactions caused by P450-mediated drug drug interaction.

Effects of parthenolide on estradiol?synthesizing enzyme, ER isoforms and VEGF in human endometriotic stromal cells / 中华妇产科杂志

Objective To evaluate the effects of parthenolide on estradiol?synthesizing enzyme, steroidogenic acute regulatory protein (StAR), and ER isoforms,VEGF in human endometriotic stromal cells. Methods Primary endometriotic stromal cells were treated with different concentrations (1, 5, 10 and 20 μmol/L) of parthenolide. The mRNA of StAR, ER isoforms (ERα and ERβ), PR, vascular endothelial growth factor (VEGF), interleukin?6 (IL?6), tumour necrosis factor?α (TNFα), tumour necrosis factor receptor (TNFR) 1, TNFR2 were measured by real?time PCR. The levels of estradiol and progesterone in the cell supernatant were measured by ELISA. Results Different concentrations of parthenolide could up?regulate the mRNA of StAR in primary endometriotic stromal cells (F=5.722, P<0.05); the mRNA of StAR in the group of 20 μmol/L was significantly higher than that of the control group [2.6 ± 0.3 versus 1.0, P<0.01]. Different concentrations of parthenolide could down?regulate the mRNA of ERα (F=6.921, P<0.01); the mRNA of ERα in the group of 20 μmol/L and 10 μmol/L were significantly lower than those of the control group [0.2 ± 0.3 versus 0.3 ± 0.3 versus 1.0, all P<0.05]. Different concentrations of parthenolide could down?regulate the ratios of ERα/ERβ mRNA levels (F=4.209, P<0.05). Different concentrations of parthenolide could up?regulate the mRNA of VEGF and TNFR1 (F=10.964, P<0.01; F=7.286, P<0.01). There were no statiscal significances with different concentrations of parthenolide on the mRNA of ERβ, PR, IL?6, TNFα and TNFR2, and the levels of estradiol and progesterone in the cell supernatant (all P>0.05). Conclusions Parthenolide may regulate the expression of estradiol?synthesizing enzyme, ER isoforms and angiogenesis in endometriotic stromal cells. Parthenolide may promote the development of endometriosis.

Effect of parthenolide on apoptosis, invasion and migration of human non-small cell lung cancer H1975 cells / 中国药理学通报

Aim To explore the effects of parthenolide (PTL) on apoptosis, invasion and migration of NSCLC cell line H1975 as well as the possible mechanism. Methods MTT assay and colony formation assay were used to measure cell proliferation. Flow cytometry with Annexin V-FITC/PI double staining were employed to measure cell apoptosis. Transwell assay was applied to measure cell invasion and migration. The expression of apoptosis-related proteins, invasion and migration-associated proteins and PBK/Akt signaling pathway-related proteins were detected using Western blot. Results MTT assay and colony formation assay results showed that the proliferation of HI975 cells was significantly inhibited with the increase of PTL concentration, and compared with control group, the differences were statistically significant (P < 0. 05). Annexin V-FITC/PI double staining result indicated that PTL induced apoptosis in HI975 cells (P <0. 01). The results of transwell assay demonstrated that PTL significantly inhibited the invasion and migration of HI975 cells (P <0. 01). Western blot analysis revealed that PTL increased the expression of Bax and reduced the expression of Bcl-2, HIF-1 a, MMP-9, Akt and p-Akt (Ser473) in HI975 cells ( P < 0. 05 ), meanwhile, the cleavage of caspase-3 was detected. Conclusions PTL can significantly induce apoptosis and inhibit the invasion and migration of HI975 cells, and the mechanism may be related to the inhibition of PI3K/Akt signaling pathway.

Parthenolide inhibits transforming growth factor β1-induced epithelial-mesenchymal transition in colorectal cancer cells

BACKGROUND/AIMS: Transforming growth factor-β1 (TGF-β1) induction of epithelial-mesenchymal transition (EMT) is one of the mechanisms by which colorectal cancer (CRC) cells acquire migratory and invasive capacities, and subsequently metastasize. Parthenolide (PT) expresses multiple anti-cancer and anti-inflammatory activities that inhibit nuclear factor κB by targeting the IκB kinase complex. In the present study, we aimed to investigate whether PT can inhibit TGF-β1-induced EMT in CRC cell lines.METHODS: HT-29 and SW480 cell lines were used in the experiment. Cell viability was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and sub-G1 analysis was measured by flow cytometry. The induction of EMT by TGF-β1 and inhibition of the process by PT was analyzed by phase contrast microscopy, wounding healing, cellular migration and invasion assays, and Western blotting.RESULTS: TGF-β1 inhibits HT-29 cell proliferation, but has no effect on SW480 cell proliferation; different concentrations of TGF-β1 did not induce apoptosis in HT-29 and SW480 cells. PT attenuates TGF-β1-induced elongated, fibroblast-like shape changing in cells. PT inhibits TGF-β1-induced cell migration and cell invasion. In addition, other EMT markers such as β-catenin, Vimentin, Snail, and Slug were suppressed by PT, while E-cadherin was increased by PT.CONCLUSIONS: Our findings show that PT inhibits TGF-β1-induced EMT by suppressing the expression of the mesenchymal protein and increasing expression of the epithelial protein. These findings suggest a novel approach for CRC treatment by suppression of TGF-β1-induced EMT.

Evaluation of plasma stability and pharmacokinetics of parthenolide in rats with LC-MS/MS analysis / 药学学报

Parthenolide is a sesquiterpene lactone derived from the plant feverfew (Tanacetum parthenium) that possesses multiple anti-inflammatory and anti-cancer properties. A specific, sensitive, accurate and precise LC-MS/MS method was developed and validated in the quantitative analysis of parthenolide in rat plasma. A liquid-liquid extraction method was used to separate the analyte and the internal standard (IS, costunolide) from plasma. A water-methanol mobile phase system was utilized in the gradient chromatographic separation. The calibration curve with good linearity (r2>0.99) was established between 2 and 128 ng·mL-1 with accuracy and precision within acceptable limits at different QC levels. High extraction recovery was achieved for both parthenolide (89.55%-95.79%) and IS (96.87%). Based on this LC-MS/MS method, the plasma stability and pharmacokinetics of parthenolide were assessed in rats. Parthenolide was proved to be very unstable in rat plasma, and was distributed and eliminated quickly in vivo, with a half-life less than 90 min. A high dose of parthenolide (80 mg·kg-1) resulted in a very low initial concentration (138.86±21.07 ng·mL-1). The systemic exposure of parthenolide (area under the curve) increased disproportionally from 40 mg·kg-1 dose group to 80 mg·kg-1 dose group. The present study may provide helpful information for the development of parthenolide as a drug candidate.

Sesquiterpenes constituents from fruits of Michelia yunnanensis / 中草药

Objective: To study the chemical constituents from fruits of Michelia yunnanensis. Methods: The chemical constituents were isolated and purified by column chromatographies on silica gel and Sephadex LH-20. Their structures were elucidated on the basis of spectroscopic data. Results: Twelve compounds were isolated from methanol extract of the fruits of M. yunnanensis and the structures were identified as 13-methoxy-11β, 13-dihydrocostunolide (1), lanuginolide (2), tulipinolide (3), lipiferolide (4), costunolide (5), parthenolide (6), 11β, 13-dihydroparthenolide (7), 4α, 5β-epoxy-13-methoxy-11βH-germacra-1 (10)-en-12, 6α-olide (8), cyperusol C (9), aromadendra-4β, 10α-diol (10), 9-oxonerolidol (11), and 11, 13-dehydrocompressanolide (12). Conclusion: Compound 1 is isolated as a new natural product. 1H-NMR and 13C-NMR data of compounds 1 and 2 are reported for the first time. Except compound 6, other compounds are isolated from this plant for the first time.

Parthenolide promotes apoptotic cell death and inhibits the migration and invasion of SW620 cells

BACKGROUND/AIMS: Parthenolide (PT), a principle component derived from feverfew (Tanacetum parthenium), is a promising anticancer agent and has been shown to promote apoptotic cell death in various cancer cells. In this study, we focused on its functional role in apoptosis, migration, and invasion of human colorectal cancer (CRC) cells. METHODS: SW620 cells were employed as representative human CRC cells. We performed the MTT assay and cell cycle analysis to measure apoptotic cell death. The wound healing, Transwell migration, and Matrigel invasion assays were performed to investigate the effect of PT on cell migration/invasion. Western blotting was used to establish the signaling pathway of apoptosis and cell migration/invasion. RESULTS: PT exerts antiproliferative effect and induces apoptotic cell death of SW620 cells. In addition, PT prevents cell migration and invasion in a dose-dependent manner. Moreover, PT markedly suppressed migration/invasion-related protein expression, including E-cadherin, β-catenin, vimentin, Snail, cyclooxygenase-2, matrix metalloproteinase-2 (MMP-2), and MMP-9 in SW620 cells. PT also inhibited the expression of antiapoptotic proteins (Bcl-2 and Bcl-xL) and activated apoptosis terminal factor (caspase-3) in a dose-dependent manner. CONCLUSIONS: Our results suggest that PT is a potential novel therapeutic agent for aggressive CRC treatment.

Performance of a commercially available plant allergen series in the assessment of suspected occupational contact dermatitis to plants in north Indian patients.

Background: Parthenium hysterophorus is the leading cause of phytogenic allergic contact dermatitis in India. The Indian Standard Series currently supplied by Systopic Laboratories Ltd and manufactured by Chemotechnique Diagnostics® contains parthenolide as the only allergen representing plant allergens. Aim: The study was conducted to assess the performance of the Chemotechnique plant series (PL-1000), consisting of 14 allergens, in patients with clinically suspected occupational contact dermatitis to plant allergens. Methods: Ninety patients were patch tested with the Chemotechnique plant series from 2011 to 2013. Demographic details, clinical diagnosis and patch test results were recorded in the contact dermatitis clinic proforma. Results: Of 90 patients, 24 (26.7%) showed positive reactions to one or more allergens in the plant series. Positive patch tests were elicited most commonly by sesquiterpene lactone mix in 19 (78.6%) patients, followed by parthenolide in 14 (57.1%), Achillea millefolium in 10 (42.9%) and others in decreasing order. Conclusion: The plant allergen series prepared by Chemotechnique Diagnostics® is possibly not optimal for diagnosing suspected allergic contact dermatitis to plants in north Indians. Sesquiterpene lactone mix should replace parthenolide as the plant allergen in the Indian Standard Series until relevant native plant extracts are commercially available for patch testing.

Effect of parthenolide on neointimal hyperplasia after balloon injury / 中国病理生理杂志

AIM:To detect the effect and underlying mechanism of parthenolide ( PN) on neointimal hyperpla-sia.METHODS:After 1 week of high-fat feeding, 30 male New Zealand white rabbits (2.0~2.3 kg) were randomly di-vided into 6 groups: sham +NS, rabbits received 0.9% normal saline after sham operation; sham +DMSO, rabbits re-ceived DMSO after sham operation;balloon injury(BI)+NS, rabbits received NS after balloon injury;BI+DMSO, rabbits received DMSO after balloon injury;BI+PN low, rabbits received PN at 1 mg/kg after balloon injury;BI+PN high, rab-bits received PN at 2 mg/kg after balloon injury .The drugs were intraperitoneal injected once a day after the operation until sacrifice.After fed with high-fat diet for 4 weeks, the intima-media thickness, the expression of caspase-1, IL-1β, the lev-els of IL-8, TC, TG, LDL and HDL in the serum were measured .RESULTS:Compared with sham +DMSO group, the thickness of intima, the amount of caspase-1, IL-1βand IL-8 in BI +DMSO group were significantly increased ( P <0.05).The levels of caspase-1, IL-1βand IL-8 were significantly decreased in BI +PN high group compared with BI +DMSO group (P<0.05).CONCLUSION:Neointimal hyperplasia is suppressed by PN after balloon injury , the potential mechanism may be associated with its anti-inflammatory role .

Molecular Mechanism of Parthenolide Improving Insulin Resistance Induced by Insulin / 医药导报

Objective To investigate the reversal effect and molecular mechanisms of NF-κB inhibitor parthenolide (PTL) on insulin resistance ( IR). Methods HepG2 cells were treated with insulin at different concentrations and time points, the glucose consumption of HepG2 cells was measured via glucose oxidase method to determine the best concentrations and time for establishing insulin-induced insulin resistance on HepG2 cells. After modeling, different concentrations of PTL were added in cells for 24 h for determining cell activity and glucose-consumption. Q-PCR was used to detect the expression of NF-κB and IκBα mRNA in cells, and western blot was used to detect the expression of protein IκBα. Results The best reaction time and concentration for insulin inducing resistance of HepG2 cells were 24 h and at 10 μg·mL-1 . The optimum acting dose of PTL was 20 μmol·L-1 . NF-κB activity was significantly reduced (P<0. 05), IκBα degradation was significantly inhibited (P<0. 05) compared to HepG2 cells with insulin resistance upon intervention on insulin resistance HepG2 cells by PTL. Conclusion PTL can inhibit IκBα degradation and disassociation of it from NF-κB, which in turn improves insulin resistance, providing theo-retical basis for preventing and treating diabetes with PTL.

Effects of parthenolide on osteoclast differentiation of RAW264. 7 cell induced by receptor activator of ;nuclear factor κB ligand / 中华风湿病学杂志

Objective To study the effects of parthenolide on osteoclast differentiation of RAW264. 7 cell induced by receptor activator of nuclear factor κB ligand (RANKL). Methods The mouse macrophage RAW264.7 cells induced by RANKL was used alone as the control group, different concentrations of par-thenolide (0.5, 1, 2 μmol/L) were added to culture the RAW264.7 cells. On the third, fifth and seventh day, the tartrate resistant acid phosphatase (TRAP) staining method was used to detect osteodast-like cells and the cell number was count;the contents of tartrate resistant acid phosphatase (TRAP5b) in the Culture supernatant of each groups were detected by enzyme linked immunosorbent assay (ELISA) and the expression of osteodast marker gene alcitonin receptor (CTR) and matrix metalloproteinase (MMP)-9 in each groups were detected by realtime-polymerase chain reaction (PCR) on the seventh day. We use Chi-square test and t test to test the differences between groups by SPSS 17.0. Results In different culture conditions, RANKL could always induce the RAW264.7 cell differentiate into mature osteoclasts. Compared with the control group at the same time control group, on the third, fifth and seventh day, he number of mature osteoclasts induced were obviously decreased in groups adding different concentration of PAR; the number of induced osteoclasts decreased along with the increase of parthenolide concentration, on the seventh day in 0.5, 1, 2 μmol/L concentration PAR groups, the number of mature osteoclasts compared with the control group were descended 36.3%, 40.8%, 49.3%(t=7.758, 8.742, 10.56;P<0.05);the contents of TRAP5b in the culture supernatant were consistent with the cell counting results on the seventh day (P<0.05). The expression of CTR and MMP-9 by TRAP positive osteoclasts decreased along with the increase of parthenolide concentration, and the 2 μmol/L group was the lowest. Compared with the control group, there were statistically significant differences with the different PAR concentration groups 0.5, 1, 2 μmol/L (P<0.05). Conclusion Parthenolide can inhibit RANKL induced RAW264.7 differentiation into osteoclast cells, and the inhibition is dose dependent.

Protective effect and mechanism of parthenolide in rats with doxorubicin-induced nephropathy / 中国生化药物杂志

Objective To observe protective effects of parthenolide ( PTN) in rats with doxorubicin-induced nephropathy and its mechanims. Methods 48 male rats were randomly divided into six groups: blank group, model group, vehicle group, and parthenolide-treated group (1.5, 3, 6 mg/kg).The models of doxorubicin-induced nephropathy were established by tail vein injection of 5 mg/kg doxorubicin for one time.After consecutive treatment of PTN for seven days, the BUN and Cr in serum, and nitricoxide (NO), malondialdehyde (MDA), nitricoxidesynthase (NOS), glutathione peroxidase (GSH), superoxide dismutase (SOD) in renal tissues were detected.The pathological changes of renal tissue was observed by HE method. ResuIts There was significant pathological changes of renal tissue in model group, that showed basophilic change, interstitial inflammatory hyperplasia and inflammatory infiltratio, after PTN 6 mg/kg treatment, the above changes significant improved.The serum BUN and Cr levels in PTN 1.5 mg/kg, PTN 3 mg/kg and PTN 6 mg/kg group were lower than those in model group (P<0.05);there were no significant differences of above indexes between PTN 3 mg/kg, PTN 6 mg/kg group and blank gorup.Compared with model group, the SOD and GSH activity were higher and MDA level was lower in three different dosage of PTN groups (P<0.05); there were no significant differences of SOD activity between PTN 3 mg/kg, PTN 6 mg/kg group and blank gorup; there were no significant differences of GSH activity and MDA level between PTN 6 mg/kg group and blank gorup.The NO level and NOS activity in three different dosage of PTN groups were higher (P<0.05);there were no significant differences of NO level and NOS activity between PTN 6 mg/kg group and blank gorup.ConcIusion Parthenolide has protective effects on doxorubicin-induced nephropathy, and its mechanism might be antioxidative effects.

Balsalazide Potentiates Parthenolide-Mediated Inhibition of Nuclear Factor-kappaB Signaling in HCT116 Human Colorectal Cancer Cells

BACKGROUND/AIMS: Balsalazide is an anti-inflammatory drug used in the treatment of inflammatory bowel disease. Balsalazide can reduce inflammatory responses via several mechanisms, including inhibition of nuclear factor-kappaB (NF-kappaB) activity. Parthenolide (PT) inhibits NF-kappaB and exerts promising anticancer effects by promoting apoptosis. The present investigated the antitumor effects of balsalazide, combined with PT, on NF-kappaB in a representative human colorectal carcinoma cell line, HCT116. METHODS: We counted cells and conducted annexin-V assays and cell cycle analysis to measure apoptotic cell death. Western blotting was used investigate the levels of proteins involved in apoptosis. RESULTS: PT and balsalazide produced synergistic anti-proliferative effects and induced apoptotic cell death. The combination of balsalazide and PT markedly suppressed nuclear translocation of the NF-kappaB p65 subunit and the phosphorylation of inhibitor of NF-kappaB. Moreover, PT and balsalazide dramatically enhanced NF-kappaB p65 phosphorylation. Apoptosis, through the mitochondrial pathway, was confirmed by detecting effects on Bcl-2 family members, cytochrome c release, and activation of caspase-3 and -8. CONCLUSIONS: Combination treatment with PT and balsalazide may offer an effective strategy for the induction of apoptosis in HCT116 cells.

Parthenolide Sensitizes Human Colorectal Cancer Cells to Tumor Necrosis Factor-related Apoptosis-inducing Ligand through Mitochondrial and Caspase Dependent Pathway

BACKGROUND/AIMS: Combination therapy utilizing tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) in conjunction with other anticancer agents, is a promising strategy to overcome TRAIL resistance in malignant cells. Recently, parthenolide (PT) has proved to be a promising anticancer agent, and several studies have explored its use in combination therapy. Here, we investigated the molecular mechanisms by which PT sensitizes colorectal cancer (CRC) cells to TRAIL-induced apoptosis. METHODS: HT-29 cells (TRAIL-resistant) were treated with PT and/or TRAIL for 24 hours. The inhibitory effect on proliferation was detected using the 3-(4, 5-dimethylthiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Annexin V staining, cell cycle analysis, and Hoechst 33258 staining were used to assess apoptotic cell death. Activation of an apoptotic pathway was confirmed by Western blot. RESULTS: Treatment with TRAIL alone inhibited the proliferation of HCT 116 cells in a dose-dependent manner, whereas proliferation was not affected in HT-29 cells. Combination PT and TRAIL treatment significantly inhibited cell growth and induced apoptosis of HT-29 cells. We observed that the synergistic effect was associated with misregulation of B-cell lymphoma 2 (Bcl-2) family members, release of cytochrome C to the cytosol, activation of caspases, and increased levels of p53. CONCLUSION: Combination therapy using PT and TRAIL might offer an effetive strategy to overcome TRAIL resistance in certain CRC cells.

Parthenolide-induced apoptosis of hepatic stellate cells and anti-fibrotic effects in an in vivo rat model

Parthenolide (PT), a sesquiterpene lactone derived from the plant feverfew, has pro-apoptotic activity in a number of cancer cell types. We assessed whether PT induces the apoptosis of hepatic stellate cells (HCSs) and examined its effects on hepatic fibrosis in an in vivo model. The effects of PT on rat HSCs were investigated in relation to cell growth inhibition, apoptosis, NF-kappaB binding activity, intracellular reactive oxygen species (ROS) generation, and glutathione (GSH) levels. In addition, the anti-fibrotic effects of PT were investigated in a thioacetamide-treated rat model. PT induced growth inhibition and apoptosis in HSCs, as evidenced by cell growth inhibition and apoptosis assays. PT increased the expression of Bax proteins during apoptosis, but decreased the expression of Bcl-2 and Bcl-XL proteins. PT also induced a reduction in mitochondrial membrane potential, poly(ADP-ribose) polymerase cleavage, and caspase-3 activation. PT inhibited TNF-alpha-stimulated NF-kappaB binding activity in HSCs. The pro-apoptotic activity of PT in HSCs was associated with increased intracellular oxidative stress as evidenced by increased intracellular ROS levels and depleted intracellular GSH levels. Furthermore, PT ameliorated hepatic fibrosis significantly in a thioacetamide-treated rat model. In conclusion, PT exhibited pro-apoptotic effects in rat HSCs and ameliorated hepatic fibrosis in a thioacetamide-induced rat model.

Synergistic Effect of Parthenolide in Combination with 5-Fluorouracil in SW480 Cells

BACKGROUND/AIMS: Parthenolide (PT) is responsible for the bioactivities of Feverfew. Besides its potent anti-inflammatory effect, this compound has recently been reported to induce apoptosis in cancer cells. Unfortunately, many of the therapies that use 5-fluorouracil (5-FU) alone or in combination with other agents are likely to become ineffective due to drug resistance. In the present study, we investigate the antitumor effect of PT combined with 5-FU on colorectal cancer cells. METHODS: SW480 cell was employed as a representative of human colorectal carcinoma (CRC) cells. We performed MTT, annexin-V assay, and Hoechst 33258 staining to measure the synergistic effect. Western blotting was used to demonstrate apoptotic pathway. RESULTS: Our result demonstrated that PT inhibited the viability of colorectal cancer cells and had synergistic anti-proliferation in combination with 5-FU. After combined treatment of 5-FU and PT, enhanced apoptotic cell death is observed using annexin-V FITC assay and it was revealed by the condensed chromatin and fragmented DNA. Compared with 5-FU or PT alone, the apoptosis of colorectal cancer cells treated with PT and 5-FU enhanced the activation of caspase-8, caspase-3. CONCLUSIONS: Combined treatment with PT may offer an efficacious strategy to overcome 5-FU resistance in certain CRC cells.

Enhancement of parthenolide-induced apoptosis by a PKC-alpha inhibition through heme oxygenase-1 blockage in cholangiocarcinoma cells

Cholangiocarcinoma (CC) is a chemoresistant intrahepatic bile duct carcinoma with a poor prognosis. The aims of this study were to identify molecular pathways that enhance sesquiterpene lactone parthenolide (PTL)-induced anticancer effects on CC cells. The effects of PTL on apoptosis and hemoxygenase-1 (HO-1) induction were examined in CC cell lines. The enhancement of PTL-mediated apoptosis by modulation of HO-1 expression and the mechanisms involved were also examined in an in vitro cell system. Low PTL concentrations (5 to 10 micrometer) led to Nrf2-dependent HO-1 induction, which attenuated the apoptogenic effect of PTL in Choi-CK and SCK cells. PTL-mediated apoptosis was enhanced by the protein kinase C-alpha inhibitor Ro317549 (Ro) through inhibition of expression and nuclear translocation of Nrf2, resulting in blockage of HO-1 expression. Finally, HO-1 silencing resulted in enhancement of apoptotic cell death in CC cells. The combination of PTL and Ro efficiently improved tumor growth inhibition compared to treatment with either agent alone in an in vivo subcutaneous tumor model. In conclusion, the modulation of HO-1 expression substantially improved the anticancer effect of PTL. The combination of PTL and Ro could prove to be a valuable chemotherapeutic strategy for CC.