PG490 (triptolide) cooperates with tumor necrosis factor-alpha to induce apoptosis in tumor cells

Does triptolide induce lysosomal-mediated apoptosis in human breast cancer cells?

With breast cancer plaguing the United States as the second leading cause of cancer related deaths amongst women, as well as the adverse effects of current treatment options there is a need to develop safer and noninvasive treatments. Triptolide is an extract from the herb Tripterygium wilfordii Hook F, and has been used in Chinese medicine for over two centuries and is now used to treat certain autoimmune diseases, such as rheumatoid arthritis. Based on the anti-proliferative, anti-inflammatory, and anti-cancer properties of triptolide we believe that it will stimulate apoptosis in human breast cancer cells. Triptolide is known to induce apoptosis in many cancer cells lines, but the exact mechanisms that regulate this are largely unknown. It has been suggested that triptolide activates the p53 pathway to trigger apoptosis in these cells. However, we believe that there are other mechanisms at work including the activation of lysosomal-mediated apoptosis.

Triptolide downregulates human GD3 synthase (hST8Sia I) gene expression in SK-MEL-2 human melanoma cells

In this study, we have shown that gene expression of human GD3 synthase (hST8Sia I) is suppressed by triptolide (TPL) in human melanoma SK-MEL-2 cells. To elucidate the mechanism underlying the downregulation of hST8Sia I gene expression in TPL-treated SK-MEL-2 cells, we characterized the TPL-inducible promoter region within the hST8Sia I gene using luciferase constructs carrying 5'-deletions of the hST8Sia I promoter. Functional analysis of the 5'-flanking region of the hST8Sia I gene demonstrated that the -1146 to -646 region, which contains putative binding sites for transcription factors c-Ets-1, CREB, AP-1 and NF-κB, functions as the TPL-inducible promoter of hST8Sia I in SK-MEL-2 cells. Site-directed mutagenesis and ChIP analysis indicated that the NF-κB binding site at -731 to -722 is crucial for TPL-induced suppression of hST8Sia I in SK-MEL-2 cells. This suggests that TPL induces down-regulation of hST8Sia I gene expression through NF-κB activation in human melanoma cells.

Triptolide and its expanding multiple pharmacological functions

Triptolide, a diterpene triepoxide, is a major active component of extracts derived from the medicinal plant Tripterygium wilfordii Hook F (TWHF). Triptolide has multiple pharmacological activities including anti-inflammatory, immune modulation, antiproliferative and proapoptotic activity. So, triptolide has been widely used to treat inflammatory diseases, autoimmune diseases, organ transplantation and even tumors. Triptolide cannot only induce tumor cell apoptosis directly, but can also enhance apoptosis induced by cytotoxic agents such as TNF-α, TRAIL and chemotherapeutic agents regardless of p53 phenotype by inhibiting NFκB activation. Recently, the cellular targets of triptolide, such as MKP-1, HSP, 5-Lox, RNA polymerase and histone methyl-transferases had been demonstrated. However, the clinical use of triptolide is often limited by its severe toxicity and water-insolubility. New water-soluble triptolide derivatives have been designed and synthesized, such as PG490-88 or F60008, which have been shown to be safe and potent antitumor agent. Importantly, PG490-88 has been approved entry into Phase I clinical trial for treatment of prostate cancer in USA. This review will focus on these breakthrough findings of triptolide and its implications.

Triptolide alleviates hepatic ischemia/reperfusion injury by attenuating oxidative stress and inhibiting NF-κB activity in mice

BACKGROUND

Hepatic I/R injury is unavoidable in liver transplantation and surgery. This remains a significant problem in surgical procedures. The purpose of this study was to investigate the effects of triptolide on liver ischemia/reperfusion (I/R) injury and related mechanisms in mice.

MATERIALS AND METHODS

Male C57BL/6 mice were randomized into four groups: (1) sham group; (2) sham-triptolide group; (3) I/R group; and (4) I-R/triptolide group. Ninety minutes of warm ischemia was induced and flow by 24 h reperfusion. Serum alanine aminotransferase and aspartate aminotransferase were assayed, pathologic alterations and (NF)-κB p65 immunohistochemistry were observed. Liver malondialdehyde (MDA) level, activity of endogenous antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities, and activity of neutrophil accumulation marker myeloperoxidase (MPO) were measured. TNF-α, IL-6, and IL-1β mRNA were detected by RT-PCR, whereas nuclear factor (NF)-κB p65 and IκBα were assessed with Western blotting.

RESULTS

Plasma aminotransferase activity was higher in the I/R group than in the I/R-triptolide group. MDA level and neutrophil infiltration were also markedly reduced, while SOD, CAT, and GSH-Px levels increased in I/R-triptolide group compared with I/R group. In group 4, histopathologic changes were significantly attenuated in triptolide-treated livers. In comparison with group 3, triptolide reduced NF-κB p65 nuclear and IκBα expression, and effectively suppressed pro-inflammatory cytokine level during the I/R.

CONCLUSIONS

These results suggest that triptolide has protective effects against hepatic I/R injury. Its mechanisms might be related to reduction of oxidative stress and neutrophil infiltration and inhibition NF-κB p65 activity.

Biologic activity of triptolide in t(8;21) acute myeloid leukemia cells

Triptolide is a compound isolated from the traditional Chinese medicinal herb Tripterygium wilfordii that shows potent anti-tumor activities, but its effects on acute myeloid leukemia with t(8;21) remain unclear. Here we report that triptolide inhibits cell proliferation and induces apoptosis in a dose- and time-dependent manner of t(8;21)-bearing Kasumi-1, SKNO-1 and CD34+ cells harvested from bone marrow samples of patients with t(8;21) leukemia. We show that triptolide triggers cleavage of the resultant AML1-ETO fusion protein of t(8;21), and causes downregulation of C-KIT followed by inhibition of JAK-STAT signaling. Triptolide downregulates p65 and inhibits the DNA-binding activity of NF-κB. Our data indicate that triptolide might be an effective agent for t(8;21) leukemia.

Targeting tumor proteasome with traditional Chinese medicine

The proteasome is a multicatalytic protease complex whose activity is required for the growth of normal or tumor cells. It has been shown that human cancer cells are more sensitive to proteasome inhibition than normal cells, indicating that the proteasome could be a target of chemotherapy. Studies suggest that traditional Chinese medicine (TCM) is an effective approach for cancer treatment. Here we reviewed several TCMs for their potential in treatment of cancer. This short review focuses mainly on the TCMs that potentially target the tumor cellular proteasome and NF-kappaB pathway whose activation is dependent on the proteasome activity.

Benzyl isothiocyanate-mediated inhibition of histone deacetylase leads to NF-kappaB turnoff in human pancreatic carcinoma cells

NF-kappaB/p65 is constitutively activated in pancreatic cancers, where it plays a critical role in the transcriptional activation of multiple cell survival genes. We have previously shown the apoptosis-inducing effects of benzyl isothiocyanate (BITC) in pancreatic cancer cells. We hypothesized that inhibition of NF-kappaB/p65 could be the mechanism of BITC-induced apoptosis. Therefore, the effect of BITC on NF-kappaB/p65 was evaluated in BxPC-3, Capan-2, and normal HPDE-6 cells by Western blotting, transcriptional and DNA-binding activity, and immunohistochemistry in the xenografted tumors. Our results reveal a remarkable decrease in the phosphorylation of NF-kappaB/p65 at Ser(536) in both BxPC-3 and Capan-2 cells by BITC treatment. The expression of NF-kappaB/p65 was downregulated significantly in BxPC-3 cells, whereas it remained unchanged in Capan-2 cells. BITC treatment caused a significant decrease in NF-kappaB transcriptional and DNA-binding activity in both BxPC-3 and Capan-2 cells. A drastic decrease was observed in the expression and reporter activity of cyclin D1 in both the cell lines. Moreover, BITC also caused a significant decrease in the expression and activity of histone deacetylase (HDAC) 1 and HDAC3 in BxPC-3 and HDAC3 in Capan-2 cells. Overexpression of HDAC1 or HDAC3 abrogated the effects of BITC. BITC treatment did not cause any change in HDAC expression in normal HPDE-6 cells. Immunohistochemical analysis of tumors from BITC-treated mice showed significantly reduced staining for NF-kappaB, cyclin D1, HDAC1, and HDAC3 compared with control. Our results suggest inhibition of HDAC1/HDAC3 by BITC as a plausible mechanism of NF-kappaB inactivation, resulting in the in vitro and in vivo growth suppression of pancreatic cancer cells.

Synergism of hydroxyapatite nanoparticles and recombinant mutant human tumour necrosis factor-alpha in chemotherapy of multidrug-resistant hepatocellular carcinoma

BACKGROUND/AIMS

Locoregional chemotherapy continues to be the mainstay for the treatment of unresectable hepatocellular carcinoma (HCC). One of the principal obstacles implicated in its unsuccessful therapy is multidrug resistance (MDR). Former studies have identified the multidrug-resistant nature and possible mechanisms of hepatoma cells both in vitro and in vivo. This work aimed to develop an effective strategy for the treatment of HCC with MDR.

METHODS

The treatment was exploited to inhibit the MDR cells by co-administration of the recombinant mutant human tumour necrosis factor-alpha (rmhTNF-alpha), a sublethal dose of chemicals [adriamycin (ADM), mitomycin and 5-FU] and hydroxyapatite nanoparticles (nHAPs). Real-time quantitative reverse transcriptase-polymerase chain reaction and electrochemiluminescence Western blot were used to detect the expression of several related genes.

RESULTS

The chemicals acted synergistically with rmhTNF-alpha and nHAP in suppressing the growth of hepatoma cells and inducing apoptosis of the cells, with the MDR phenotype reversed, as measured by intracellular ADM retention. Analysis of mRNA and protein revealed that rmhTNF-alpha inhibited the gene expression of XIAP, survivin, Ki67, PCNA, MDR1 and BCRP to some extent. Moreover, the inhibitory effects mentioned above could be as good or better than when nHAP is incorporated into the regimens.

CONCLUSIONS

rmhTNF-alpha was not only able to restore the chemotherapeutic sensitivity to HepG2/ADM, its xenograft model and clinical samples but also further inhibited the growth of these tumours by a combination of nHAP. These results strongly suggested that chemicals in combination with rmhTNF-alpha and nHAP may be beneficial for the local treatment of advanced HCC.

Triptolide-induced suppression of phospholipase D expression inhibits proliferation of MDA-MB-231 breast cancer cells

In spite of the importance of phospholipase D (PLD) in cell proliferation and tumorigenesis, little is known about the molecules regulating PLD expression. Thus, identification of small molecules inhibiting PLD expression would be an important advance for PLD- mediated physiology. We examined one such here, denoted Triptolide, which was identified in a chemical screen for inhibitors of PLD expression using cell assay system based on measurement of PLD promoter activity. Triptolide significantly suppressed the expression of both PLD1 and PLD2 with sub-mM potency in MDA-MB-231 breast cancer cells as analyzed by promoter assay and RT-PCR. Moreover, triptolide abolished the protein level of PLD in a time and dose-dependent manner. Triptolide-induced PLD1 downregulation was also observed in all the cancer cells examined, suggesting a general phenomenon detected in various cancer cells. Decrease of PLD expression by triptolide suppressed both basal and PMA-induced PLD activity. In addition, triptolide inhibited activation of NFkB which increased PLD1 expression. Ultimately, downregulation of PLD by triptolide inhibited proliferation of breast cancer cells. Taken together, we demonstrate that triptolide suppresses the expression of PLD via inhibition of NFkappaB activation and then decreases cell proliferation.

RNA polymerase - an important molecular target of triptolide in cancer cells

Triptolide, a diterpenoid triepoxide, is the key biological component of Tripterygium wilfordii Hook. f. which was used in traditional Chinese medicine for centuries to treat inflammation and autoimmune diseases. Triptolide has shown potent activity in not only anti-inflammation and immune modulation, but also antiproliferative and proapoptotic activity in many different types of cancer cells. However, for a long time, the precise molecular target(s) of triptolide have remained elusive. Recently, several groups discovered that triptolide inhibited the activity of RNA polymerase. This review will focus on these breakthrough findings about the molecular target of triptolide and its implications for targeted-cancer therapeutics.

Anti-angiogenic activity of triptolide in anaplastic thyroid carcinoma is mediated by targeting vascular endothelial and tumor cells

Triptolide is confirmed to suppress angiogenesis of anaplastic thyroid carcinoma. Here we further expound the precise mechanism involved in this activity. Triptolide downregulated nuclear factor kappa B (NF-kappaB) pathway and its targeting genes associated with endothelial cell mobilization in human umbilical vein endothelial cells (HUVECs) and impaired VEGF expression in thyroid carcinoma TA-K cells. Furthermore, both triptolide and the conditioned medium from triptolide-treated TA-K cells (CMT) significantly attenuated proliferation, migration and tube formation of HUVECs. In vivo, triptolide inhibited TA-K cell-induced tumor growth, vascular formation and VEGF expression. Our data establish that triptolide inhibits tumor angiogenesis by the dual action on vascular endothelial cells and tumor cells, thus providing a novel and overall explanation for the anti-angiogenesis action of triptolide. The multicellular targets emphasize triptolide as a high-performance and potential angiogenesis inhibitor.

Induction of dual specificity phosphatase 1 (DUSP1) by gonadotropin-releasing hormone (GnRH) and the role for gonadotropin subunit gene expression in mouse pituitary gonadotroph L beta T2 cells

We examined the expression of dual specificity phosphatase 1 (DUSP1) by gonadotropin-releasing hormone (GnRH) stimulation and investigated the role of DUSP1 on gonadotropin gene expression using LbetaT2 gonadotroph cell line. DUSP1 expression was markedly increased 60 min after GnRH stimulation, and mitogen-activated protein kinase 3/1 (MAPK3/1) activation was gradually decreased after 60 min. GnRH-induced MAPK3/1 activation was completely inhibited by U0126, a MEK inhibitor, whereas GnRH-induced DUSP1 expression was partially inhibited by U0126. GnRH-induced DUSP1 induction was inhibited by triptolide, a diterpenoid triepoxide. In contrast, this compound potentiated MAPK3/1 activation. U0126 prevented GnRH-stimulated gonadotropin subunit promoter activation dose dependently, and 10 muM of U0126 reduced the effects of GnRH on the Lhb and Fshb promoters to 79.15% and 55.66%, respectively. GnRH-stimulated activation of Lhb and Fshb promoters as well as serum response factor (Srf) promoters were almost completely inhibited by triptolide, suggesting that this component had a nonspecific effect to the cells. Dusp1 siRNA reduced the expression of DUSP1 and augmented MAPK3/1 phosphorylation, but it did not increase of gonadotropin promoters. By overexpression of DUSP1, both GnRH-stimulated Lhb and Fshb promoters were significantly reduced. We have previously shown that insulin-like growth factor 1 (IGF1) increases MAPK3/1 but does not activate gonadotropin subunit promoters. IGF1 failed to induce DUSP1 expression. In addition, under pulsatile GnRH stimulation, DUSP1 expression was observed following high-frequency GnRH pulses but not following low-frequency pulses. Our study demonstrated that DUSP1, induced by GnRH, functions not only as an MAPK3/1-inactivating phosphatase but also as an important mediator in gonadotropin subunit gene expression regulation.

Involvement of MKP-1 and Bcl-2 in acquired cisplatin resistance in ovarian cancer cells

Although cisplatin is a very effective anticancer agent against several types of cancer including ovarian cancer, the mechanisms of acquired resistance are not fully understood. By chronically exposing cisplatin to ovarian cancer cell lines, we established two cisplatin-resistant cell lines OV433 and TOV112D. Our results indicate that the mechanisms underlying their cisplatin resistance are distinct. In OV433 cells, cisplatin resistance is associated with increased expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1). By knocking down MKP-1 expression by siRNA or inhibiting MKP-1 expression by its pharmacological inhibitor triptolide, cisplatin-resistant OV433 cells became cisplatin-sensitive and subsequently increased cisplatin-induced apoptosis. In TOV112D cells, on the other hand, acquired cisplatin resistance is associated with increased levels of Bcl-2 protein. By inhibiting the activity of Bcl-2 protein with its pharmacological inhibitor gossypol or knocking down Bcl-2 expression by siRNA, cisplatin-resistant TOV112D cells became cisplatin-sensitive and subsequently increased cisplatin-induced apoptosis. Therefore, our data suggest that the mechanisms of acquired cisplatin resistance vary among ovarian cancer cells, which involve upregulation of molecules associated with the cell survival pathways.

Regression of Polypoid Nasal Mucosa after Systemic Corticosteroid Therapy: A Proteomics Study

Background

Nasal polyposis (NP) treatment and pathophysiology have always been challenging for otolaryngologists. Among the medical treatments for NP, glucocorticoids (GCs) have been always one of the mainstays but the mechanisms of their action are not well defined. Identifying and comparing the protein profile of chronic rhinosinusitis (CRS) with NP before and after treatment with GCs can help to clarify NP pathogenesis and mechanisms of corticosteroid effects on NP.

Methods

Samples of nasal polyps were taken from selected NP patients in workup for endoscopic sinus surgery. None of the patients used local or systemic GCs within 30 days before the sampling. The patients were given prednisone, 30 mg/day, for 4 days before the surgery to shrink the NP tissue. Nasal polyp samples were collected during surgery. Proteins from samples were extracted and separated by immobilized pH gradient–based two-dimensional difference gel electrophoresis (2D DIGE). Resulting 2D-gel images were statistically analyzed using Delta2D software and differently expressed protein spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Results

A reference map of 1963 proteins could be established. Expression of 20 proteins changed significantly (twofold, p < 0.05) after treatment of NP with GCs. Heat shock proteins and retinoic acid were induced by GCs. Ingenuity pathway analysis of all identified proteins indicated that apoptosis pathway is triggered in NP after GC administration.

Conclusion

Identifying the changes of NP proteome due to GCs and the biological functions of proteins can lead to new ways of treatment and open new fields in NP research.

Comparison of Tripterygium wilfordii Hook F versus sulfasalazine in the treatment of rheumatoid arthritis: a randomized trial

BACKGROUND

Extracts of the medicinal plant Tripterygium wilfordii Hook F (TwHF) have been used in China for centuries to treat a spectrum of inflammatory diseases.

OBJECTIVE

To compare the benefits and side effects of TwHF extract with those of sulfasalazine for the treatment of active rheumatoid arthritis.

DESIGN

Randomized, controlled trial. A computer-generated code with random, permuted blocks was used to assign treatment.

SETTING

2 U.S. academic centers (National Institutes of Health, Bethesda, Maryland, and University of Texas, Dallas, Texas) and 9 rheumatology subspecialty clinics (in Dallas and Austin, Texas; Tampa and Fort Lauderdale, Florida; Arlington, Virginia; Duncanville, Pennsylvania; Wheaton and Greenbelt, Maryland; and Lansing, Michigan).

PATIENTS

121 patients with active rheumatoid arthritis and 6 or more painful and swollen joints.

INTERVENTION

TwHF extract, 60 mg 3 times daily, or sulfasalazine, 1 g twice daily. Patients could continue stable doses of oral prednisone or nonsteroidal anti-inflammatory drugs but had to stop taking disease-modifying antirheumatic drugs at least 28 days before randomization.

MEASUREMENTS

The primary outcome was the rate of achievement of 20% improvement in the American College of Rheumatology criteria (ACR 20) at 24 weeks. Secondary end points were safety; radiographic scores of joint damage; and serum levels of interleukin-6, cholesterol, cortisol, and adrenocorticotropic hormone.

RESULTS

Outcome data were available for only 62 patients at 24 weeks. In a mixed-model analysis that imputed data for patients who dropped out, 65.0% (95% CI, 51.6% to 76.9%) of the TwHF group and 32.8% (CI, 21.3% to 46.0%) of the sulfasalazine group met the ACR 20 response criteria (P=0.001). Patients receiving TwHF also had significantly higher response rates for ACR 50 and ACR 70 in mixed-model analyses. Analyses of only completers showed similar significant differences between the treatment groups. Significant improvement was demonstrated in all individual components of the ACR response, including the Health Assessment Questionnaire disability score. Interleukin-6 levels rapidly and significantly decreased in the TwHF group. Although not statistically significant, radiographic progression was lower in the TwHF group. The frequency of adverse events was similar in both groups.

LIMITATIONS

Only 62% and 41% of patients continued receiving TwHF extract and sulfasalazine, respectively, during the 24 weeks of the study. Long-term outcome data were not collected on participants who discontinued treatment.

CONCLUSION

In patients who continued treatment for 24 weeks and could also use stable oral prednisone and nonsteroidal anti-inflammatory drugs, attainment of the ACR 20 response criteria was significantly greater with TwHF extract than with sulfasalazine.

Repression of TNF-alpha-induced IL-8 expression by the glucocorticoid receptor-beta involves inhibition of histone H4 acetylation

Increased expression of a number of proinflammatory genes, including IL-8, is associated with inflammatory conditions such as asthma. Glucocorticoid receptor (GR)beta, one of the GR isoforms, has been suggested to be upregulated in asthma associated with glucocorticoid insensitivity and to work as a dominant negative inhibitor of wild type GRalpha. However, recent data suggest that GRbeta is not a dominant negative inhibitor of GRalpha in the transrepressive process and has its own functional role. We investigated the functional role of GRbeta expression in the suppressive effect of glucocorticoids on tumor necrosis factor (TNF)-alpha-induced IL-8 release in an airway epithelial cell line. GRbeta expression was induced by treatment of epithelial cells with either dexamethasone or TNF-alpha. GRbeta was able to inhibit glucocorticoid-induced transcriptional activation mediated by binding to glucocorticoid response elements (GREs). The suppressive effect of dexamethasone on TNF-alpha-induced IL-8 transcription was not affected by GRbeta overexpression, rather GRbeta had its own weak suppressive activity on TNF-alpha-induced IL-8 expression. Overall histone deacetylase activity and histone acetyltransferase activity were not changed by GRbeta overexpression, but TNF-alpha-induced histone H4 acetylation at the IL-8 promoter was decreased with GRbeta overexpression. This study suggests that GRbeta overexpression does not affect glucocorticoid-induced suppression of IL-8 expression in airway epithelial cells and GRbeta induces its own histone deacetylase activity around IL-8 promoter site.

Triptolide inhibits proliferation and migration of colon cancer cells by inhibition of cell cycle regulators and cytokine receptors

BACKGROUND

Phytochemicals are an important source of emerging preventive and therapeutic agents for cancer. Triptolide/PG490, an extract of the Chinese herb Tripterygium wilfordii Hook F, is a potent anti-inflammatory agent that also possesses anticancer activity. While its antiproliferative effects are well-established, the potential antimigratory effects of triptolide have not been characterized.

MATERIAL AND METHODS

Effects of triptolide on the proliferation and invasion of colon cancer cells and expression of cancer-related genes and proteins were assessed.

RESULTS

Triptolide potently inhibited HT29 and HCT116 colon cancer cell growth and reduced basal and stimulated HCT116 migration through collagen by 65% to 80%. Triptolide inhibited mRNA expression of the positive cell cycle regulatory genes c-myc, and A, B, C, and D-type cyclins in multiple colon cancer cell lines. Additionally, we show that triptolide treatment decreased expression of VEGF and COX-2, which promote cancer progression and invasion, and inhibited the expression of multiple cytokine receptors potentially involved in cell migration and cancer metastasis, including the thrombin receptor, CXCR4, TNF receptors, and TGF-β receptors.

CONCLUSIONS

Triptolide is a potent inhibitor of colon cancer proliferation and migration in vitro. The down-regulation of multiple cytokine receptors, in combination with inhibition of COX-2 and VEGF and positive cell cycle regulators, may contribute to the antimetastatic action of this herbal extract.

Immunosuppressive effects of demethylzeylasteral in a rat kidney transplantation model

In this study, we examined the immunosuppressive activity of demethylzeylasteral (T-96), isolated from the traditional Chinese herbal medicine, Tripterygium wilfordii Hook f. Its immunosuppressive effect was investigated using mouse splenocytes in vitro, and in an in vivo rat kidney transplant model. T-96 inhibited mouse splenocyte proliferation in a dose dependent manner. In the rat kidney transplant study, rats were randomly divided into eight groups following kidney transplantation, and different doses of T-96 or cyclosporin A (CsA) were administered to each group. T-96 alone at doses of 10 or 20 mg/kg/day significantly prolonged the survival of kidney-transplanted rats, compared with transplanted but untreated control rats. A combination of T-96 and prednisone also significantly prolonged survival: 10 mg/kg/day T-96 with 10 mg/kg/day prednisone increased the survival time to 31.8+/-6.5 days. Moreover, the combination of T-96 and prednisone was also effective in suppressing rejection of rat transplanted kidneys. These results demonstrate the strong immunosuppressive activity of T-96 and suggest a possible clinical use for T-96 as an immunosuppressive agent in the fields of organ transplantation and autoimmune disorders.

A small-molecule triptolide suppresses angiogenesis and invasion of human anaplastic thyroid carcinoma cells via down-regulation of the nuclear factor-kappa B pathway

Anaplastic thyroid carcinoma (ATC) is among the most aggressive malignancies known and is characterized with rapid growth, early invasion, and complete refractoriness to current therapies. Here we report that triptolide, a small molecule from a Chinese herb, could potently inhibit proliferation in vitro, angiogenesis in vivo, and invasion in a Matrigel model in human ATC cell line TA-K cells at nanomolar concentrations. We further elucidate that triptolide inhibits the nuclear factor-kappaB (NF-kappaB) transcriptional activity via blocking the association of p65 subunit with CREB-binding protein (CBP)/p300 in the early stage and via decreasing the protein level of p65 in the late stage. Expression of the NF-kappaB targeting genes cyclin D1, vascular endothelial growth factor, and urokinase-type plasminogen activator is significantly reduced by triptolide in both TA-K and 8505C human ATC cell lines, which are well known to be critical for proliferation, angiogenesis, and invasion in solid tumors. Our findings suggest that triptolide may function as a small molecule inhibitor of tumor angiogenesis and invasion and may provide novel mechanistic insights into the potential therapy for human ATC.

A new dawn for the use of traditional Chinese medicine in cancer therapy

Although traditional Chinese medicine has benefitted one fifth of the world's population in treating a plethora of diseases, its acceptance as a real therapeutic option by the West is only now emerging. In light of a new wave of recognition being given to traditional Chinese medicine by health professionals and regulatory bodies in the West, an understanding of their molecular basis and highlighting potential future applications of a proven group of traditional Chinese medicine in the treatment of a variety of cancers is crucial – this is where their calling holds much hope and promise in both animal and human trials. Furthermore, the rationale for combining conventional agents and modern biotechnological approaches to the delivery of traditional Chinese medicine is an avenue set to revolutionize the future practice of cancer medicine – and this may well bring on a new dawn of therapeutic strategies where East truly meets West.

Tripterygium wilfordii hook f increase the blood concentration of tacrolimus

OBJECTIVE

To observe the influence of the Tripterygium wilfordii Hook F (T II) on the blood concentration of tacrolimus and analyze the impact of this effect.

METHOD

Twenty-two renal transplant receipts taking tacrolimus combined with the T II were selected for this study. We analyzed the blood concentrations and the rate of concentration compared with dosage (C/D rate) pre- and postcombination over 6 months. All cases underwent the CYP3A5 genotype test.

RESULT

The concentrations of tacrolimus were raised to a certain degree after the combination in all the cases. The first-time elevation differed from 1 week to 4 months. The C/D rate increased by 1.7 to 7.2 times with most evaluated C/D rates ranging from 1.8 to 3.8. The elevated C/D rate of the subgroup of CYP3A5 1/1 and 1/3 (n = 10) contrasted with the 3/3 genotype subgroup (n = 12: 2.99 +/- 1.71 vs 2.55 +/- 1.07; P = .472). The mycophenolate mofetil subgroup (n = 17) was not contrasted to the mizoribine subgroup (n = 5: 2.85 +/- 1.51 vs 2.31 +/- 0.26; P = .498).

CONCLUSION

T II considerably increased the blood concentration and the C/D rate of tacrolimus. The degree of increase was probably not related to the CYP3A5 genotype and the combination of immunosuppressive agents.

Triptolide inhibits COX-2 expression and PGE2 release by suppressing the activity of NF-kappaB and JNK in LPS-treated microglia

Activated microglia participate in neuroinflammation which contributes to neuronal damage in neurodegenerative diseases. Inhibition of microglial activation may have potential anti-inflammatory effects. Our laboratory has previously reported that triptolide, a natural biologically active compound extracted from Tripterygium wilfordii, could protect dopaminergic neurons from inflammation-mediated damage. However, the mechanism by which triptolide inhibits inflammation remains unknown. We reported here that inhibition of prostaglandin E(2) (PGE(2)) production could be a potential mechanism of triptolide to suppress inflammation. Triptolide suppressed c-jun NH2-terminal kinase (JNK) phosphorylation, cyclooxygenase 2 (COX-2) expression and PGE(2) production in microglial cultures treated with lipopolysaccharide (LPS). Triptolide also greatly inhibited the transcriptional activity, but not the DNA-binding activity of nuclear factor-kappaB (NF-kappaB) in microglia following LPS stimulation. These results indicate that triptolide might suppress NF-kappaB activity to down-regulate COX-2 expression. The LPS-stimulated transcriptional activity of NF-kappaB was suppressed by inhibition of p38MAPK, but not by that of JNK and extracellular signal-regulated kinase. Furthermore, the LPS-induced PGE(2) production was reduced by inhibiting these kinases. Taken together, these results suggest that triptolide may suppress neuroinflammation via a mechanism that involves inactivation of two parallel signaling pathways: p38-NF-kappaB-COX-2-PGE(2) and JNK-PGE(2).

Apoptosis of human pancreatic cancer cells induced by Triptolide

AIM: To investigate apoptosis in human pancreatic cancer cells induced by Triptolide (TL), and the relationship between this apoptosis and expression of caspase-3’ bcl-2 and bax.

METHODS: Human pancreatic cancer cell line SW1990 was cultured in DMEM media for this study. MTT assay was used to determine the cell growth inhibitory rate in vitro. Flow cytometry and TUNEL assay were used to detect the apoptosis of human pancreatic cancer cells before and after TL treatment. RT-PCR was used to detect the expression of apoptosis-associated gene caspase-3’ bcl-2 and bax.

RESULTS: TL inhibited the growth of human pancreatic cancer cells in a dose-and time-dependent manner. TL induced human pancreatic cancer cells to undergo apoptosis with typically apoptotic characteristics. TUNEL assay showed that after the treatment of human pancreatic cancer cells with 40 ng/mL TL for 12 h and 24 h, the apoptotic rates of human pancreatic cancer cells increased significantly. RT-PCR demonstrated that caspase-3 and bax were significantly up-regulated in SW1990 cells treated with TL while bcl-2 mRNA was not.

CONCLUSION: TL is able to induce the apoptosis in human pancreatic cancer cells. This apoptosis may be mediated by up-regulating the expression of apoptosis-associated caspase-3 and bax gene.

Triptolide sensitizes AML cells to TRAIL-induced apoptosis via decrease of XIAP and p53-mediated increase of DR5

Acute myeloid leukemia (AML) cells are relatively resistant to tumor necrosis factor alpha-related apoptosis-inducing ligand (TRAIL). We previously reported that triptolide, a potent anticancer agent from a Chinese herb, decreases XIAP in leukemic cells. We evaluated the combination of triptolide and TRAIL and found synergistic promotion of apoptosis in AML cells. XIAP-overexpressing U937 cells (U937XIAP) were more resistant to TRAIL than U937neo cells, and inhibition of XIAP with the small-molecule inhibitor 1396-11 enhanced TRAIL-induced apoptosis, implying XIAP as a resistance factor in AML. Furthermore, triptolide increased DR5 levels in OCI-AML3, while the DR5 increase was blunted in p53-knockdown OCI-AML3 and p53-mutated U937 cells, confirming a role for p53 in the regulation of DR5. In support of this finding, disruption of MDM2-p53 binding with subsequent increase in p53 levels by nutlin3a increased DR5 levels and sensitized OCI-AML3 cells to TRAIL. The combination of 1396-11 plus nutlin3a plus TRAIL was more effective than either the 1396-11 and TRAIL or nutlin3a and TRAIL combinations in OCI-AML3 cells, further supporting the role of triptolide as a sensitizer to TRAIL-induced apoptosis in part by independent modulation of XIAP expression and p53 signaling. Thus, the combination of triptolide and TRAIL may provide a novel strategy for treating AML by overcoming critical mechanisms of apoptosis resistance.

Differential regulation of survivin by p53 contributes to cell cycle dependent apoptosis

Recent studies indicate that cell-cycle checkpoints are tightly correlated with the regulation of apoptosis, in which p53 plays an important role. Our present works show that the expression of E6/E7 oncogenes of human papillomavirus in HeLa cells is inhibited in the presence of anti-tumor reagent tripchlorolide (TC), which results in the up-regulation of p53 in HeLa cells. Interestingly, under the same TC-treatment, the cells at the early S-phase are more susceptible to apoptosis than those at the middle S-phase although p53 protein is stabilized to the same level in both situations. Significant difference is exhibited between the two specified expression profiles. Further analysis demonstrates that anti-apoptotic gene survivin is up-regulated by p53 in the TC-treated middle-S cells, whereas it is down-regulated by p53 in the TC-treated early-S cells. Taken together, the present study indicates that the differential p53-regulated expression of survivin at different stages of the cell cycle results in different cellular outputs under the same apoptosis-inducer.

Traditional Chinese herbal medicines for treatment of liver fibrosis and cancer: from laboratory discovery to clinical evaluation

Liver disease afflicts over 10% of the world population. This includes chronic hepatitis, alcoholic steatosis, fibrosis, cirrhosis and hepatocellular carcinoma (HCC), which are the most health-threatening conditions drawing considerable attention from medical professionals and scientists. Patients with alcoholism or viral hepatitis are much more likely to have liver cell damage and cirrhosis, and some may eventually develop HCC, which is unfortunately, and very often, a fatal malignancy without cure. While liver surgery is not suitable in many of the HCC cases, patients are mostly given palliative support cares or transarterial chemoembolization or systemic chemotherapies. However, HCC is well known to be a highly chemoresistant tumour, and the response rate is <10-20%. To this end, alternative medicines are being actively sought from other sources with hopes to halt the disease's progression or even eliminate the tumours. Traditional Chinese herbal medicine has begun to gain popularity worldwide for promoting healthcare as well as disease prevention, and been used as conventional or complementary medicines for both treatable and incurable diseases in Asia and the West. In this article, we discuss the laboratory findings and clinical trial studies of Chinese herbal medicines (particularly small molecule compounds) for the treatment of liver disease ranging from fibrosis to liver cancer.

Inhibitors of the heat shock response: biology and pharmacology

A number of human diseases can be linked to aberrations in protein folding which cause an imbalance in protein homeostasis. Molecular chaperones, including heat shock proteins, act to assist protein folding, stability and activity in the cell. Attention has begun to focus on modulating the expression and/or activity of this group of proteins for the treatment of a wide variety of human diseases. This review will describe the progress made to date in developing pharmacological modulators of the heat shock response, including both agents which affect the entire heat shock response and those that specifically target the HSP70 and HSP90 chaperone families.

Triptolide binds covalently to a 90 kDa nuclear protein. Role of epoxides in binding and activity

Triptolide is a naturally occurring diterpene triepoxide whose anti-inflammatory effects correlate with transcriptional inhibition of various cytokines. Despite its use in herbal medicine for thousands of years, the cellular target and mode of action of this drug are unknown. [3H]-triptolide was prepared and a filtration assay designed to measure binding to cells and cellular extracts. Triptolide bound specifically and irreversibly to a single, 90 kDa protein in nuclear extracts from stimulated and non-stimulated monocytic and epithelial cell lines. Thiol reactivity of one or more of the epoxides on triptolide was necessary for the covalent binding, since thiol oxidizing agents dithiodipyridine and diamide, and the thiol alkylating agent N-ethylmaleimide all reduced the binding of [3H]-triptolide to nuclear extract. Neither glutathione nor the pro-oxidant tert-butylhydroperoxide affected the binding of [3H]-triptolide to the nuclear protein, ruling out a general oxidant effect. The number of epoxide moieties correlated with the ability to compete with radiolabeled triptolide for binding to the nuclear extract and with the potency of inhibition of TNFalpha secretion from monocytes, IL-2 secretion from Jurkat cells, and with inhibition of RNA synthesis. The correlation between the structure-activity relationship and observed binding suggests that identification of the triptolide binding protein could provide insight into the cellular mode of action of this anti-inflammatory natural product.

Association of cooking oil fumes exposure with lung cancer: Involvement of inhibitor of apoptosis proteins in cell survival and proliferation in vitro

Cooking oil fumes (COF) have been shown to be associated with lung cancer incidence in Chinese women. Our recent report indicates that inhibitor of apoptosis protein 2 (IAP2) induced by COF may contribute to the survival and proliferation of A549 lung cancer cells. In this study, to further verify whether other antiapoptosis proteins including IAP1, X-linked IAP (XIAP), and survivin, were linked with lung cancer cell survival and proliferation, these IAPs expressions in A549 cells after treatment with COF and its two major components, benzo[a]pyrene (BaP) and 2,4-decadienal (2,4-DDE) were evaluated by Western blotting. Our data showed that IAP2 was significantly induced by COF, BaP, and 2,4-DDE, but XIAP was decreased by COF and 2,4-DDE, but not by BaP. Even though different effects of COF and 2,4-DDE on IAP2 and XIAP protein expressions were observed, the caspase-3 expression was diminished by COF and 2,4-DDE. In addition, induction of IAP2 and phosphorylated Akt proteins by COF and 2,4-DDE were simultaneously abolished by LY294002. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) analysis showed that the proportion of A549 cells at the S-phase was increased significantly after treatment with COF or 2,4-DDE. The cell proliferation induced by COF is associated with the attenuation of p21(Cip/Waf1) expression. Therefore, increases of IAP1, IAP2, survivin, and cyclin D1 expressions and decreases of XIAP, caspase-3, and p21 expressions might partly contribute to the survival and proliferation of lung cancer cells after exposure to 2,4-DDE and COF. In conclusion, the lung cancer cell growth promoted by COF might support previous epidemiological reports indicating that exposure of COF was associated with lung cancer development among Chinese women.

Suppression of 5-lipoxygenase gene is involved in triptolide-induced apoptosis in pancreatic tumor cell lines

Pancreatic adenocarcinoma is characterized by a poor prognosis and lack of response to conventional therapy. The purpose of this study was to investigate the effects of triptolide (TL) on proliferation and apoptosis of pancreatic cancer cells in vitro. We found that TL induced prominent growth inhibition and apoptosis in human pancreatic cell lines. In addition, TL treatment significantly down-regulated 5-lipoxygenase (5-LOX) expression, as well as downstream leukotriene B4 (LTB4) production, in these cell lines. Furthermore, overexpression of 5-LOX in SW1990 cell lines or exogenous LTB4 made them more resistant to TL-induced apoptosis, which was correlated with increased Bcl-2 expression. Taken together, these findings suggest that inhibition of the 5-LOX pathway of arachidonic acid metabolism is associated with the anti-proliferation activity of TL. We also provide evidence that TL has clinical therapeutic value for patients with pancreatic cancer.

Triptolide is a traditional Chinese medicine-derived inhibitor of polycystic kidney disease

During kidney organogenesis, tubular epithelial cells proliferate until a functional tubule is formed as sensed by cilia bending in response to fluid flow. This flow-induced ciliary mechanosensation opens the calcium (Ca(2+)) channel polycystin-2 (PC2), resulting in a calcium flux-mediated cell cycle arrest. Loss or mutation of either PC2 or its regulatory protein polycystin-1 (PC1) results in autosomal dominant polycystic kidney disease (ADPKD), characterized by cyst formation and growth and often leading to renal failure and death. Here we show that triptolide, the active diterpene in the traditional Chinese medicine Lei Gong Teng, induces Ca(2+) release by a PC2-dependent mechanism. Furthermore, in a murine model of ADPKD, triptolide arrests cellular proliferation and attenuates overall cyst formation by restoring Ca(2+) signaling in these cells. We anticipate that small molecule induction of PC2-dependent calcium release is likely to be a valid therapeutic strategy for ADPKD.

Herbal diterpenoids induce growth arrest and apoptosis in colon cancer cells with increased expression of the nonsteroidal anti-inflammatory drug-activated gene

Novel chemotherapeutic agents derived from active phytochemicals could be used as adjuvants and improve the anti-carcinogenicity of standard drug treatments. However, their precise mechanisms of action are sometimes unclear. In this study, the anti-carcinogenic effect of the herbal diterpenoid pseudolaric acid B (PAB) on the growth and apoptosis of colon cancer cells was investigated, and to compare that with the more toxic compound triptolide. PAB induced growth inhibition and apoptosis in HT-29 cells, which were associated with cell cycle arrest at the G(2)/M phase, modulation of cyclin expression and downregulation of the protooncogene c-myc. In addition, PAB also inhibited bcl-x(L) expression, induced cleavage of procaspase-3 and its substrate poly(ADP-ribose) polymerase (PARP), which together caused DNA fragmentation and nuclear chromatin condensation. Concomitantly, the modulation of the growth-related and apoptotic factors by PAB was accompanied by the increased protein and gene expression of the nonsteroidal anti-inflammatory drug-activated gene (NAG-1), which occurred along with cyclooxygenase-2 inhibition. The effects of PAB on PARP cleavage and NAG-1 overexpression were not reversible upon removal of the drug from the culture medium. Similar cytotoxic and pro-apoptotic effects were also attained by treating the HT-29 cells with another diterpenoid triptolide, but its actions on cell cycle progression and on the upstream transcriptional regulation of NAG-1 both took place in a less coherent manner. These findings exemplify the potential of herbal terpenoids, particularly PAB, in modulating colon cancer carcinogenesis through known molecular targets and precise mechanism of action.

Cancer relapse under chemotherapy: why TLR2/4 receptor agonists can help

Liver or lung metastases usually relapse under chemotherapy. Such life-threatening condition urgently needs new, systemic anticancer compounds, with original and efficient mechanisms of action. In B16 melanoma mice treated with cyclophosphamide, D'Agostini et al. [D'Agostini, C., Pica, F., Febbraro, G., Grelli, S., Chiavaroli, C., Garaci, E., 2005. Antitumour effect of OM-174 and Cyclophosphamide on murine B16 melanoma in different experimental conditions. Int. Immunopharmacol. 5, 1205-1212.] recently found that OM-174, a chemically defined Toll-like receptor(TLR)2/4 agonist, reduces tumor progression and prolongs survival. Here we review 149 articles concerning molecular mechanisms of TLR2/4 agonists, alone or in combination with chemotherapy. It appears that TLR2/4 agonists induce a well controlled tumor necrosis factor-alpha (TNF-alpha) secretion, at plasma levels known to permeabilize neoangiogenic tumor vessels to the passage of cytotoxic drugs. Moreover, TLR2/4 agonists induce inducible nitric oxide synthase (iNOS) expression, and nitric oxide is able to induce apoptosis of chemotherapy-resistant tumor cell clones. Finally, TLR2/4-stimulation activates dendritic cell traffic and its associated tumor-specific, cytotoxic T-cell responses. Therefore, parenteral TLR2/4 agonists seem promising molecules to prolong survival in cancer patients who relapse under chemotherapy.

TNF-alpha in cancer treatment: molecular insights, antitumor effects, and clinical utility

Tumor necrosis factor alpha (TNF-alpha), isolated 30 years ago, is a multifunctional cytokine playing a key role in apoptosis and cell survival as well as in inflammation and immunity. Although named for its antitumor properties, TNF has been implicated in a wide spectrum of other diseases. The current use of TNF in cancer is in the regional treatment of locally advanced soft tissue sarcomas and metastatic melanomas and other irresectable tumors of any histology to avoid amputation of the limb. It has been demonstrated in the isolated limb perfusion setting that TNF-alpha acts synergistically with cytostatic drugs. The interaction of TNF-alpha with TNF receptor 1 and receptor 2 (TNFR-1, TNFR-2) activates several signal transduction pathways, leading to the diverse functions of TNF-alpha. The signaling molecules of TNFR-1 have been elucidated quite well, but regulation of the signaling remains unclear. Besides these molecular insights, laboratory experiments in the past decade have shed light upon TNF-alpha action during tumor treatment. Besides extravasation of erythrocytes and lymphocytes, leading to hemorrhagic necrosis, TNF-alpha targets the tumor-associated vasculature (TAV) by inducing hyperpermeability and destruction of the vascular lining. This results in an immediate effect of selective accumulation of cytostatic drugs inside the tumor and a late effect of destruction of the tumor vasculature. In this review, covering TNF-alpha from the molecule to the clinic, we provide an overview of the use of TNF-alpha in cancer starting with molecular insights into TNFR-1 signaling and cellular mechanisms of the antitumor activities of TNF-alpha and ending with clinical response. In addition, possible factors modulating TNF-alpha actions are discussed.

Triptolide induces Bcl-2 cleavage and mitochondria dependent apoptosis in p53-deficient HL-60 cells

Triptolide, a bioactive component of the Chinese medicinal herb Tripterygium wilfordii Hook F., induces p53-mediated apoptosis in cancer cells. This study demonstrated that triptolide activated an alternative p53-independent apoptotic pathway in HL-60 cells. In the absence of an intact p53 and without changing Bax level, at nM range triptolide induced apoptosis with concomitant DNA fragmentation, S phase cell cycle arrest, mitochondrial cytochrome c release and the activation of caspases. Besides, both caspases 8 and 9 were activated and the simultaneous inhibition of both was required to completely block triptolide's apoptotic effect. Importantly, triptolide induced the appearance of a truncated 23kD Bcl-2 which was inhibited by the general caspase inhibitor Z-VAD-FMK. In the MCF-7 cells that possessed the wild type p53 but lacked caspases 3, triptolide induced cell death with an increase in p53 but Bcl-2 remained unaltered. On the other hand, transfected cells overexpressing the 28kD Bcl-2 became more resistant to triptolide and upon triptolide treatment accumulated in the G(1) instead of S phase. After 36h treatment, triptolide activated JNK pathways, at the same time inactivated the ERK and p38 pathways. However, SP600125, a specific JNK inhibitor, could not inhibit the triptolide-mediated cleavage of caspase 3, indicated that activation of JNK might not be related to the apoptotic effects of triptolide. Our data suggest that in the absence of an intact p53 and without altering Bax level triptolide induces apoptosis activates a positive amplification loop involving caspase-mediated Bcl-2 cleavage/activation, mitochondrial cytochrome c release and further activation of caspases.

Clinical trial of Tripterygium Wilfordii Hook F. in human kidney transplantation in China

OBJECTIVE

In this study, the effects of Triptergium Wilfordii Hook F.(T II) were assessed on human kidney allograft rejection and long-term survival.

METHODS

This study compared treatment with T II(T II group, n=121) to that without T II(control group, n=102) among adult first cadaveric renal transplant recipients. The T II cohort of 121 recipients were divided into a regular dosage group (n=82) and a double dosage group (n=39). No antibody induction was administered to any patient.

RESULTS

Biopsy-proven early acute allograft rejection occurred in 4.1% of patients in the T II group versus 24.5% of patients in the control group. No rejection or repeated rejections occurred in the double dosage group at 3 months after transplantation. Acute rejection episodes were milder in the T II than the control group. The incidence of CD25+ cells>10/ mm3 in the allografts at 3 months after transplantation was lower in the T II group than the control group, 15% and 50%, respectively. All patients tolerated T II well over the 5 years of this study. The 5-year graft survival censored for death with function was 96.7% in the T II group and 80.4% in the control group.

CONCLUSION

T II was effective to prevent renal allograft rejection and increase long-term renal allograft survival among adult cadaveric renal transplant recipients.

Triptolide, an Inhibitor of the Human Heat Shock Response That Enhances Stress-induced Cell Death

Molecular chaperones, inducible by heat shock and a variety of other stresses, have critical roles in protein homeostasis, balancing cell stress with adaptation, survival, and cell death mechanisms. In transformed cells and tumors, chaperones are frequently overexpressed, with constitutive activation of the heat shock transcription factor HSF1 implicated in tumor formation. Here, we describe the activity of triptolide, a diterpene triepoxide from the plant Triptergium wilfordii, as an inhibitor of the human heat shock response. Triptolide treatment of human tissue culture cells prevented the inducible expression of heat shock genes, shown by suppression of an HSP70 promoter-reporter construct and by suppression of endogenous HSP70 gene expression. Upon examining the steps in the HSF1 activation pathway, we found that triptolide abrogates the transactivation function of HSF1 without interfering in the early events of trimer formation, hyperphosphorylation, and DNA binding. The ability of triptolide to inhibit the heat shock response renders these cells sensitive to stress-induced cell death, which may be of great relevance to cancer treatments.