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Ho CL, Wang JL, Lee CC, Cheng HY, Wen WC, Cheng HHY, Chen MCM. Antroquinonol blocks Ras and Rho signaling via the inhibition of protein isoprenyltransferase activity in cancer cells. Biomed Pharmacother 2014; 68:1007-14. [PMID: 25312820 DOI: 10.1016/j.biopha.2014.09.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/14/2014] [Indexed: 11/28/2022] Open
Abstract
Antroquinonol is the smallest anticancer molecule isolated from Antrodia camphorata thus far. The ubiquinone-like structure of Antroquinonol exhibits a broad spectrum of activity against malignancies in vivo and in vitro. However, the mechanism of action of Antroquinonol remains unclear. Here, we provide evidence that Antroquinonol plays a role in the inhibition of Ras and Ras-related small GTP-binding protein functions through the inhibition of protein isoprenyl transferase activity in cancer cells. Using cell line-based assays, we found that the inactive forms of Ras and Rho proteins were significantly elevated after treatment with Antroquinonol. We also demonstrated that Antroquinonol binds directly to farnesyltransferase and geranylgeranyltransferase-I, which are key enzymes involved in activation of Ras-related proteins, and inhibits enzymes activities in vitro. Furthermore, a molecular docking analysis illustrated that the isoprenoid moiety of Antroquinonol binds along the hydrophobic cavity of farnesyltransferase similar to its natural substrate, farnesyl pyrophosphate. In contrast, the ring structure of Antroquinonol lies adjacent to the Ras-CAAX motif-binding site on farnesyltransferase. The molecular docking study also showed a reasonable correlation with the IC50 values of Antroquinonol analogues. We also found that the levels of LC3B-II and the autophagosome-associated LC3 form were also significantly increased in H838 after Antroquinonol administration. In conclusion, Antroquinonol inhibited Ras and Ras-related GTP-binding protein activation through inhibition of protein isoprenyl transferase activity, leading to activation of autophagy and associated mode of cell death in cancer cells.
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Affiliation(s)
- Ching-Liang Ho
- Division of Hematology/Oncology, Department of Internal Medicine, Tri-Service General Hospital, Neihu, 114, Taipei, Taiwan, ROC
| | - Jui-Ling Wang
- Agriculture Biotechnology Research Center, Academia Sinica, Nankang, 115 Taipei, Taiwan, ROC
| | - Cheng-Chung Lee
- National Core Facilities for Protein Structural Analysis, Nankang, 115 Taipei, Taiwan, ROC
| | - Hsiu-Yi Cheng
- Division of Biological Chemistry, Golden Biotechnology Corp., Danshui Dist., 251 New Taipei City, Taiwan, ROC
| | - Wu-Che Wen
- Division of Biological Chemistry, Golden Biotechnology Corp., Danshui Dist., 251 New Taipei City, Taiwan, ROC
| | - Howard Hao-Yu Cheng
- Division of Biological Chemistry, Golden Biotechnology Corp., Danshui Dist., 251 New Taipei City, Taiwan, ROC
| | - Miles Chih-Ming Chen
- Division of Biological Chemistry, Golden Biotechnology Corp., Danshui Dist., 251 New Taipei City, Taiwan, ROC.
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Garamszegi N, Garamszegi SP, Scully SP. Matrix metalloproteinase-1 contribution to sarcoma cell invasion. J Cell Mol Med 2012; 16:1331-41. [PMID: 21801306 PMCID: PMC3823085 DOI: 10.1111/j.1582-4934.2011.01402.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Matrix metalloproteinase-1 (MMP-1) activity has been linked to numerous disease processes from arthritis to ulcer. Its proteolytic activity has been implicated inconsistently in different steps of tumourigenesis and metastasis. The discrepancies may be attributable to our limited understanding of MMP-1 production, cellular trafficking, secretion and local activation. Specifically, regulation of MMP-1 directional delivery versus its general extracellular matrix secretion is largely unknown. Inhibition of prenylation by farnesyl transferase inhibitor (FTI-276) decreased extracellular MMP-1 and subsequently reduced invasiveness by 30%. Parallel, stable cell line RNAi knockdown of MMP-1 confirmed its role in cellular invasiveness. The prenylation agonist farnesyl pyrophosphate (FPP) partially normalized FTI-276 inhibited extracellular MMP-1 levels and invasion capacity while transiently delayed its cellular podia distribution. MMP-1 directional delivery to these structures were confirmed by combination of a MMP-1–specific fluorogenic substrate, a MMP1-Ds-Red fusion protein construct expression and DQ-collagen degradation, which demonstrated coupling of directional delivery and activation. MetaMorph analysis of cellular lamellipodia structures indicated that FTI-276 inhibited formation and delivery to these structures. Farnesyl pyrophosphate partially restored lamellipodia area but not MMP-1 delivery under the time frame investigated. These results indicate that MMP-1 directional delivery to podia structures is involved in the invasive activity of sarcoma cells, and this process is prenylation sensitive.
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Affiliation(s)
- Nandor Garamszegi
- Sarcoma Biology Laboratory of Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine, FL, USA.
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Aguilar B, Amissah F, Duverna R, Lamango NS. Polyisoprenylation potentiates the inhibition of polyisoprenylated methylated protein methyl esterase and the cell degenerative effects of sulfonyl fluorides. Curr Cancer Drug Targets 2011; 11:752-62. [PMID: 21599633 DOI: 10.2174/156800911796191015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 04/15/2011] [Indexed: 11/22/2022]
Abstract
The polyisoprenylation pathway incorporates a reversible step that metabolizes polyisoprenylated methylated proteins from the ester to the carboxylate form. Polyisoprenylated protein methyl transferase (PPMTase) catalyses the esterification whereas polyisoprenylated methylated protein methyl esterase (PMPMEase) hydrolyzes them. Significant changes in the balance between the two enzymes may alter polyisoprenylated protein function possibly resulting in disease. Previous studies show that PMPMEase is the serine hydrolase, Sus scrofa carboxylesterase. Its susceptibility to the nonspecific serine hydrolase inhibitor, phenylmethylsulfonyl fluoride (PMSF) paved the way for its use as a prototypical compound to design and synthesize a series of putative high affinity specific inhibitors of PMPMEase. Pseudo first-order kinetics revealed an over 680-fold increase in k(obs)/[I] values from PMSF (6 M(-1)-1s(-1)), S-phenyl (L-50, 180 M(-1)s(-1)), S-benzyl (L-51, 350 M(-1)s(-1)), S-trans, trans-farnesyl (L-28, 2000 M(-1)s(-1)), to S-trans-geranylated (L-23, 4100 M(-1)s(-1)) 2-thioethanesulfonyl fluorides. C10 S-alkyl substitution revealed a k(obs)/[I] value (1800 M(-1)s(-1)) that was 298 times greater than that for PMSF. The compounds induced the degeneration of human neuroblastoma SH-SY5Y cells with EC(50) values of 49, 130 and >1000 µM for L-28, L-23 and PMSF, respectively. The increased affinity with the polyisoprenyl derivatization is consistent with the observed substrate specificity and the reported hydrophobic nature of the active site. These results suggest that (1) PMPMEase is a key enzyme for polyisoprenylated protein metabolism, (2) regulation of its activity is essential for maintaining normal cell viability, (3) abnormal activities may be involved in degenerative diseases and cancers and (4) its specific inhibitors may be useful in combating cancers.
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Affiliation(s)
- Byron Aguilar
- College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida 32307, USA
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Synergistic Effect of Geranylgeranyltransferase Inhibitor, GGTI, and Docetaxel on the Growth of Prostate Cancer Cells. Prostate Cancer 2011; 2012:989214. [PMID: 22111007 PMCID: PMC3195320 DOI: 10.1155/2012/989214] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 03/08/2011] [Indexed: 11/25/2022] Open
Abstract
Most advanced prostate cancers progress to castration resistant
prostate cancer (CRPC) after a few years of androgen deprivation
therapy and the prognosis of patients with CRPC is poor. Although
docetaxel and cabazitaxel can prolong the survival of patients
with CRPC, inevitable progression appears following those
treatments. It is urgently required to identify better or
alternative therapeutic strategies. The purpose of this study was
to confirm the anti-cancer activity of zoledronic acid (Zol) and
determine whether inhibition of geranylgeranylation in the
mevalonate pathway could be a molecular target of prostate cancer
treatment. We examined the growth inhibitory effect of Zol in
prostate cancer cells (LNCaP, PC3, DU145) and investigated a role
of geranylgeranylation in the anticancer activity of Zol. We,
then, evaluated the growth inhibitory effect of
geranylgeranyltransferase inhibitor (GGTI), and analyzed the
synergy of GGTI and docetaxel by combination index and
isobolographic analysis. Zol inhibited the growth of all prostate
cancer cell lines tested in a dose-dependent manner through
inhibition of geranylgeranylation. GGTI also inhibited the
prostate cancer cell growth and the growth inhibitory effect was
augmented by a combination with docetaxel. Synergism between GGTI
and docetaxel was observed across a broad range of concentrations.
In conclusion, our results demonstrated that GGTI can inhibit the
growth of prostate cancer cells and has synergistic effect with
docetaxel, suggesting its potential role in prostate cancer
treatment.
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Houben R, Michel B, Vetter-Kauczok CS, Pföhler C, Laetsch B, Wolter MD, Leonard JH, Trefzer U, Ugurel S, Schrama D, Becker JC. Absence of classical MAP kinase pathway signalling in Merkel cell carcinoma. J Invest Dermatol 2006; 126:1135-42. [PMID: 16498399 DOI: 10.1038/sj.jid.5700170] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Merkel cell carcinoma (MCC) is a highly metastatic skin tumor. To assess the relevance of the Ras/Raf/MEK/MAP kinase pathway, we analyzed for activating B-Raf mutations and we elucidated the presence of the Raf Kinase Inhibitor Protein (RKIP) and extracellular signal-regulated kinase (ERK) as well as the phosphorylation status of ERK. All MCC samples were negative for the B-Raf(V600E) mutation. Remarkably, RKIP, which was shown to interfere with the activation of MEK by Raf, was highly expressed in primary as well as in metastatic MCC. Immunohistochemical analysis of the phosphorylation status of ERK revealed in 42 out of 44 samples a complete lack of activated ERK in the tumor cells although ERK is expressed; in the two positive cases phosphorylated ERK was restricted to a minor fraction of the tumor cells. Western blot analysis of three MCC-derived cell lines revealed in one case the pattern present in situ (i.e. high RKIP expression and complete absence of phosphorylated ERK). In summary, our data demonstrate the inactivity of the classical MAP kinase signal transduction pathway in MCC, which seems to be because of lack of activation as well as active deactivation. These findings should be accounted for in future therapeutic approaches for this tumor.
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Affiliation(s)
- Roland Houben
- Klinik und Poliklinik für Haut- und Geschlechtskrankheiten, Julius-Maximilians-University Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany.
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Abstract
Ras proteins play fundamental roles in cell signal transduction pathways that regulate cell growth, differentiation, proliferation, and survival. ras mutations are among the most frequently encountered genetic abnormalities in human cancers and play a key role in tumorigenesis. The enzymatic attachment of a 15- or 20-carbon moiety to the Ras protein through farnesylation or geranylgeranylation, respectively, is a required step in the proper localization and activation of Ras. Inhibition of the catalytic enzymes, farnesyl transferase and geranylgeranyl transferase, is a novel, mechanism-based, targeted approach to cancer therapy development. Geranylgeranyl transferase inhibitors suppress tumor growth by accumulating cells in the G(1)/S cell cycle phase. One mechanism by which farnesyl transferase inhibitors suppress tumor growth is by inhibiting bipolar spindle formation, thereby blocking progression from prophase to metaphase. Although the exact molecular target responsible for the antitumor activity of farnesyl transferase inhibitors is unclear, at least in some tumor cells, inhibition of phosphoinositide-3-OH kinase/Akt-mediated cell survival pathways may play a critical role. Identifying the farnesylated proteins that are targeted by farnesyl transferase inhibitors and the tumor molecular signatures that dictate which set of patients will respond to farnesyl transferase inhibitors are critical end points for future mechanistic studies.
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Affiliation(s)
- Saïd M Sebti
- Drug Discovery Program, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida, Tampa, Florida 33612, USA.
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Abstract
The farnesyltransferase inhibitors (FTIs) were designed to inhibit the post-translational processing of Ras proteins, which are mutated in 30% of all human cancers. Recent studies suggest, however, that the target of FTIs may be a protein other than Ras, and that these agents may be more appropriately used to treat tumors with activated wild-type ras signaling. Preliminary results from several phase II and phase III studies have been reported. The FTIs fail to show significant single-agent activity in non-small cell lung cancer, small cell lung cancer, pancreatic cancer, refractory colorectal cancer, and bladder cancer. Activity has been shown in hematologic malignancies (acute myeloid leukemia, chronic myeloid leukemia, myelodysplastic syndrome), breast cancer, and glioma. Several combination studies of FTIs and standard cytotoxic agents are ongoing.
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Affiliation(s)
- Saïd M Sebti
- Drug Discovery Program, H. Lee Moffitt Cancer Center & Research Institute, Department of Oncology, University of South Florida College of Medicine, Tampa, FL 33612, USA
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Sebti SM, Hamilton AD. Farnesyltransferase and geranylgeranyltransferase I inhibitors and cancer therapy: lessons from mechanism and bench-to-bedside translational studies. Oncogene 2000; 19:6584-93. [PMID: 11426643 DOI: 10.1038/sj.onc.1204146] [Citation(s) in RCA: 226] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In 1990, more than 10 years after the discovery that the low molecular weight GTPase Ras is a major contributor to human cancer, farnesylation, a lipid posttranslational modification required for the cancer-causing activity of Ras, emerged as a major target for the development of novel anticancer agents. However, it took only 5 years from 1993, when the first farnesyltransferase inhibitors (FTIs) were reported, to 1998 when results from the first phase I clinical trials were described. This rapid progress was due to the demonstration of outstanding antitumor activity and lack of toxicity of FTIs in preclinical models. Although, many FTIs are currently in phase H and at least one is in phase III clinical trial, the mechanism of FTI antitumor activity is not known. In this review a brief summary of the development of FTIs as antitumor agents will be given. The focus of the review will be on important mechanistic and bench-to-bedside translational issues. Among the issues that will be addressed are: evidence for and against inhibition of the prenylation of Ras and RhoB proteins in the mechanism of action of FTIs; implications of the alternative prenylation of K-Ras by geranylgeranyl-transferase I (when FTase is inhibited) in cancer therapy; GGTase I inhibitors (GGTIs) as antitumor agents; effects of FTIs and GGTIs on cell cycle machinery and progression and potential mechanisms by which FTIs and GGTIs induce apoptosis in human cancer cells. A thorough discussion about bench-to-bedside issues relating to hypothesis-driven clinical trials with proof-of-principle in man will also be included. This section will cover issues relating to whether the biochemical target (FTase) is inhibited and the level of inhibition of FTase required for clinical response; are signaling pathways such as H-Ras/PI3K/Akt and/or K-Ras/Raf/MEK/Erk relevant biological readouts?; is Ras (particularly N-Ras and H-Ras) mutation status a good predictor of clinical response?; in phase I trials should effective biological dose, not maximally tolerated dose, be used to determine phase II dose?; and finally, in phase II/III trials what are the most appropriate clinical end points for anti-signaling molecules such as FTIs? Parts of this topic have been recently reviewed (Sebti and Hamilton, 2000c).
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Affiliation(s)
- S M Sebti
- Department of Oncology, University of South Florida College of Medicine, Tampa, USA
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Sebti SM, Hamilton AD. Farnesyltransferase and geranylgeranyltransferase I inhibitors in cancer therapy: important mechanistic and bench to bedside issues. Expert Opin Investig Drugs 2000; 9:2767-82. [PMID: 11093352 DOI: 10.1517/13543784.9.12.2767] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The fact that proteins such as Ras, Rac and RhoA require farnesylation or geranylgeranylation to induce malignant transformation prompted many investigators to develop farnesyltransferase (FTase) and geranylgeranyltransferase I (GGTase I) inhibitors (FTIs and GGTIs, respectively) as novel anticancer drugs. Although FTIs have been shown to antagonise oncogenic signalling, reverse malignant transformation, inhibit human tumour growth in nude mice and induce tumour regression in transgenic mice without any signs of toxicity, their mechanism of action is not known. This review will focus on important mechanistic issues as well as bench to bedside translational issues. These will include the relevance to cancer therapy of the alternative geranylgeranylation of K-Ras when FTase is inhibited; a thorough discussion about evidence for and against the involvement of inhibition of prenylation of Ras and RhoB in the mechanism of FTIs' antitumour activity as well as effects of FTIs and GGTIs on the cell cycle machinery and the dynamics of bipolar spindle formation and chromosome alignment during mitosis. Bench to bedside issues relating to the design of hypothesis-driven clinical trials with biochemical correlates for proof-of-concept in man will also be discussed. This will include Phase I issues such as determining maximally tolerated dose (MTD) versus effective biological dose (EBD), as well as whether Phase II trials are still needed for clinical evaluations of anti-signalling agents. Other questions that will be addressed include: what levels of inhibition of FTase activity are required for tumour response in Phase II clinical evaluations? What FTase substrates are most relevant as biochemical correlates? Are signalling pathways such as H-Ras/PI3K/Akt and K-Ras/Raf/MEK/Erk significant biological readouts? Does Ras mutation status predict response? What are appropriate clinical end-points for FTI Phase II trials? For this latter important question, time to tumour progression, median survival, percentage of patients that progress, clinical benefits and improvement in quality of life will all be discussed.
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Affiliation(s)
- S M Sebti
- Drug Discovery Program, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612, USA.
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