Enhanced Antitumor Effect of Combined Triptolide and Ionizing Radiation

University of Rochester, Rochester, New York, United States
Clinical Cancer Research (Impact Factor: 8.72). 09/2007; 13(16):4891-9. DOI: 10.1158/1078-0432.CCR-07-0416
Source: PubMed


The lack of effective treatment for pancreatic cancer results in a very low survival rate. This study explores the enhancement of the therapeutic effect on human pancreatic cancer via the combination of triptolide and ionizing radiation (IR).
In vitro AsPC-1 human pancreatic cancer cells were treated with triptolide alone, IR alone, or triptolide plus IR. Cell proliferation was analyzed with sulforhodamine B (SRB) method and clonogenic survival; comparison of apoptosis induced by the above treatment was analyzed by annexin V-propidium iodide (PI) staining. Furthermore, the expression of apoptotic pathway intermediates was measured by the assay of caspase activity and Western blot. Mitochondrial transmembrane potential was determined by JC-1 assay. In vivo, AsPC-1 xenografts were treated with 0.25 mg/kg triptolide, 10 Gy IR, or triptolide plus IR. The tumors were measured for volume and weight at the end of the experiment. Tumor tissues were tested for terminal nucleotidyl transferase-mediated nick end labeling (TUNEL) and immunohistochemistry.
The combination of triptolide plus IR reduced cell survival to 21% and enhanced apoptosis, compared with single treatment. In vivo, tumor growth of AsPC-1 xenografts was reduced further in the group treated with triptolide plus IR compared with single treatment. TUNEL and immunohistochemistry of caspase-3 cleavage in tumor tissues indicated that the combination of triptolide plus IR resulted in significantly enhanced apoptosis compared with single treatments.
Triptolide in combination with ionizing radiation produced synergistic antitumor effects on pancreatic cancer both in vitro and in vivo and seems promising in the combined modality therapy of pancreatic cancer.

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    • "In this study, we found that combination of triptolide with radiation showed more effective anti-tumor activity compared to the treatment with triptolide or radiation alone. Wang et al [37] also found that triptolide sensitized pancreatic cancer cells to radiation therapy. These findings suggest that triptolide may be a potent radiosensitizer in laryngocarcinoma therapy. "
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    ABSTRACT: Triptolide, an active compound extracted from Chinese herb Leigongteng (Tripterygium wilfordii Hook F.), shows a broad-spectrum of anticancer activity through its cytotoxicity. However, the efficacy of triptolide on laryngocarcinoma rarely been evaluated, and the mechanism by which triptolide-induced cellular apoptosis is still not well understood. In this study, we found that triptolide significantly inhibited the laryngocarcinoma HEp-2 cells proliferation, migration and survivability. Triptolide induces HEp-2 cell cycle arrest at the G1 phase and apoptosis through intrinsic and extrinsic pathways since both caspase-8 and -9 are activated. Moreover, triptolide enhances p53 expression by increasing its stability via down-regulation of E6 and E6AP. Increased p53 transactivates down-stream target genes to initiate apoptosis. In addition, we found that short time treatment with triptolide induced DNA damage, which was consistent with the increase in p53. Furthermore, the cytotoxicity of triptolide is decreased by p53 knockdown or use of caspases inhibitor. In conclusion, our results demonstrated that triptolide inhibits cell proliferation and induces apoptosis in laryngocarcinoma cells by enhancing p53 expression and activating p53 functions through induction of DNA damage and suppression of E6 mediated p53 degradation. These studies indicate that triptolide is a potential anti-laryngocarcinoma drug.
    Full-text · Article · Nov 2013 · PLoS ONE
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    • "Various studies have also indicated that it exhibits antitumor activities as indicated by suppression of cell growth and induction of apoptosis in a broad range of human cancer cells [4] [5]. In addition, triptolide inhibited experimental metastasis in a nude mouse model [6] and sensitized tumors to radiation [7]. How diterpene mediates these effects is not fully understood, but downregulation of various targets such as XIAP [8], COX-2 [9], iNOS [10], uPAR [11], CCR7 [12], and upregulation of death receptor-5 (DR-5) [13], p53 [14], and HSP-70 [15] have all been implicated. "
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    ABSTRACT: Triptolide, a diterpene triepoxide, from the Chinese herb Tripterygium wilfordii Hook.f, exerts its anti-inflammatory and immunosuppressive activities by inhibiting the transcription factor nuclear factor-κB (NF-κB) pathway, through a mechanism not yet fully understood. We found that triptolide, in nanomolar concentrations, suppressed both constitutive and inducible NF-κB activation, but did not directly inhibit binding of p65 to the DNA. The diterpene did block TNF-induced ubiquitination, phosphorylation, and degradation of IκBα, the inhibitor of NF-κB and inhibited acetylation of p65 through suppression of binding of p65 to CBP/p300. Triptolide also inhibited the IκBα kinase (IKK) that activates NF-κB and phosphorylation of p65 at serine 276, 536. Furthermore, the NF-κB reporter activity induced by TNF-TNFR1-TRADD-TRAF2-NIK-TAK1-IKKβ was abolished by the triepoxide. Triptolide also abrogated TNF-induced expression of cell survival proteins (XIAP, Bcl-x(L), Bcl-2, survivin, cIAP-1 and cIAP-2), cell proliferative proteins (cyclin D1, c-myc and cyclooxygenase-2), and metastasis proteins (ICAM-1 and MMP-9). This led to enhancement of apoptosis induced by TNF, taxol, and thalidomide by the diterpene and to suppression of tumor invasion. Overall, our results demonstrate that triptolide can block the inflammatory pathway activated by TNF-TNFR1-TRADD-TRAF2-NIK-TAK1-IKK, sensitizes cells to apoptosis, and inhibits invasion of tumor cells.
    Preview · Article · Jul 2011 · Biochemical pharmacology
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    • "incubated for another 24 or 48 h. Cell growth was evaluated by SRB protein staining assay [Houghton et al., 2007] and expressed as percentage of vehicle-treated control [Wang et al., 2007]. "
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    ABSTRACT: Estrogen receptor alpha (ERα) plays an important role in the development and progression of breast cancer and thus the attenuation of ERα activities is a promising treatment strategy. Furanodienone is one of the main bioactive chemical components of Rhizoma Curcumae which is commonly used in Chinese medicine for the treatment of cancer. In this study, we investigated the effects of furanodienone on human breast cancer MCF-7, T47D, and MDA-MB-231 cells. Our results showed that furanodienone could inhibit MCF-7, T47D, and MDA-MB-231 cells proliferation in a dose (10-160 µM) dependent manner. ERα-negative MDA-MB-231 cells were less sensitive to furanodienone than ERα-positive MCF-7 and T47D cells. Furanodienone could effectively block 17β-estradiol (E2)-stimulated MCF-7 cell proliferation and cell cycle progression and induce apoptosis evidenced by the flow cytometric detection of sub-G1 DNA content and the appearance of apoptotic nuclei after DAPI staining. Furanodienone specifically down-regulated ERα protein and mRNA expression levels without altering ERβ expression. Furanodienone treatment inhibited E2-stimulation of estrogen response element (ERE)-driven reporter plasmid activity and ablated E2-targeted gene (e.g., c-Myc, Bcl-2, and cyclin D1) expression which resulted in the inhibition of cell cycle progression and cell proliferation, and in the induction of apoptosis. Knockdown of ERα in MCF-7 cells by ERα-specific siRNA decreased the cell growth inhibitory effect of furanodienone. These findings suggest that effects of furanodienone on MCF-7 cells are mediated, at least in part, by inhibiting ERα signaling.
    Full-text · Article · Jan 2011 · Journal of Cellular Biochemistry
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