1
|
Dong S, Chen Z, Wang L, Liu Y, Stagos D, Lin X, Liu M. Marine Bromophenol Bis(2,3,6-Tribromo-4,5-Dihydroxybenzyl)ether Inhibits Angiogenesis in Human Umbilical Vein Endothelial Cells and Reduces Vasculogenic Mimicry in Human Lung Cancer A549 Cells. Mar Drugs 2021; 19:641. [PMID: 34822512 PMCID: PMC8617710 DOI: 10.3390/md19110641] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/08/2021] [Accepted: 11/12/2021] [Indexed: 12/11/2022] Open
Abstract
Angiogenesis, including the growth of new capillary blood vessels from existing ones and the malignant tumors cells formed vasculogenic mimicry, is quite important for the tumor metastasis. Anti-angiogenesis is one of the significant therapies in tumor treatment, while the clinical angiogenesis inhibitors usually exhibit endothelial cells dysfunction and drug resistance. Bis(2,3,6-tribromo-4,5-dihydroxybenzyl)ether (BTDE), a marine algae-derived bromophenol compound, has shown various biological activities, however, its anti-angiogenesis function remains unknown. The present study illustrated that BTDE had anti-angiogenesis effect in vitro through inhibiting human umbilical vein endothelial cells migration, invasion, tube formation, and the activity of matrix metalloproteinases 9 (MMP9), and in vivo BTDE also blocked intersegmental vessel formation in zebrafish embryos. Moreover, BTDE inhibited the migration, invasion, and vasculogenic mimicry formation of lung cancer cell A549. All these results indicated that BTDE could be used as a potential candidate in anti-angiogenesis for the treatment of cancer.
Collapse
Affiliation(s)
- Songtao Dong
- Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China; (S.D.); (Z.C.); (L.W.); (Y.L.)
- Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Zhongyuan Chen
- Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China; (S.D.); (Z.C.); (L.W.); (Y.L.)
| | - Li Wang
- Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China; (S.D.); (Z.C.); (L.W.); (Y.L.)
| | - Yankai Liu
- Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China; (S.D.); (Z.C.); (L.W.); (Y.L.)
| | - Dimitrios Stagos
- Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Biopolis, 41500 Larissa, Greece;
| | - Xiukun Lin
- Department of Pharmacology, School of Pharmacy, Southwest Medical University, 319 Zhongshan Road, Jiangyang, Luzhou 646000, China;
| | - Ming Liu
- Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China; (S.D.); (Z.C.); (L.W.); (Y.L.)
- Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| |
Collapse
|
2
|
Robustaflavone induces G0/G1 cell cycle arrest and apoptosis in human umbilical vein endothelial cells and exhibits anti-angiogenic effects in vivo. Sci Rep 2020; 10:11070. [PMID: 32632123 PMCID: PMC7338547 DOI: 10.1038/s41598-020-67993-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 06/15/2020] [Indexed: 11/25/2022] Open
Abstract
We investigated the anti-angiogenic and pro-apoptotic effects of robustaflavone (RF), a naturally occurring biflavonoid, on human umbilical vein endothelial cells (HUVECs). RF inhibited HUVEC proliferation and showed cytotoxicity that inhibited HUVEC viability. RF-induced apoptosis was characterized by flow cytometry and caspase 3 analysis. We found that RF increased the number of sub-G1 cells and terminal deoxynucleotidyl transferase dUTP nick end-labeled cells. Additionally, RF induced caspase 3 and poly (ADP-ribose) polymerase activation. Potential molecular targets were identified using a human apoptosis antibody array. RF upregulated Bax, Bad, cleaved caspase 3, p21, and phosphorylated p53 levels. RF induced mitochondrial membrane potential loss and the release of cytochrome c and apoptosis-inducing factor. Cell cycle arrest at G0/G1 phase and the downregulation of Cdk4, Cdk6, and cyclin D1 expression were induced by RF. In vivo anti-angiogenic effects were investigated using a tumor allograft animal model and a Matrigel plug assay. RF reduced the volumes and weights of CT-26 cell-derived tumors. The blood vessel density was significantly decreased in RF-treated tumors. RF also inhibited VEGF-A-stimulated blood vessel formation in vivo in Matrigel plugs. These results suggest that RF can potentially inhibit angiogenesis-dependent tumor growth and metastasis.
Collapse
|
3
|
Xie X, Zhang Y, Li F, Lv T, Li Z, Chen H, Jia L, Gao Y. Challenges and Opportunities from Basic Cancer Biology for Nanomedicine for Targeted Drug Delivery. Curr Cancer Drug Targets 2019; 19:257-276. [DOI: 10.2174/1568009618666180628160211] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/15/2018] [Accepted: 06/22/2018] [Indexed: 12/11/2022]
Abstract
Background:Effective cancer therapy is still a great challenge for modern medical research due to the complex underlying mechanisms of tumorigenesis and tumor metastasis, and the limitations commonly associated with currently used cancer therapeutic options. Nanotechnology has been implemented in cancer therapeutics with immense potential for improving cancer treatment.Objective:Through information about the recent advances regarding cancer hallmarks, we could comprehensively understand the pharmacological effects and explore the mechanisms of the interaction between the nanomaterials, which could provide opportunities to develop mechanism-based nanomedicine to treat human cancers.Methods:We collected related information and data from articles.Results:In this review, we discussed the characteristics of cancer including tumor angiogenesis, abnormalities in tumor blood vessels, uncontrolled cell proliferation markers, multidrug resistance, tumor metastasis, cancer cell metabolism, and tumor immune system that provide opportunities and challenges for nanomedicine to be directed to specific cancer cells and portray the progress that has been accomplished in application of nanotechnology for cancer treatment.Conclusion:The information presented in this review can provide useful references for further studies on developing effective nanomedicine for the treatment of cancer.
Collapse
Affiliation(s)
- Xiaodong Xie
- Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou, Fujian 350116, China
| | - Yingying Zhang
- Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou, Fujian 350116, China
| | - Fengqiao Li
- Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou, Fujian 350116, China
| | - Tingting Lv
- Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou, Fujian 350116, China
| | - Ziying Li
- Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou, Fujian 350116, China
| | - Haijun Chen
- Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou, Fujian 350116, China
| | - Lee Jia
- Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou, Fujian 350116, China
| | - Yu Gao
- Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou, Fujian 350116, China
| |
Collapse
|
4
|
da Costa PLN, Wynne D, Fifis T, Nguyen L, Perini M, Christophi C. The kallikrein-Kinin system modulates the progression of colorectal liver metastases in a mouse model. BMC Cancer 2018; 18:382. [PMID: 29618333 PMCID: PMC5885419 DOI: 10.1186/s12885-018-4260-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 03/20/2018] [Indexed: 01/06/2023] Open
Abstract
Background The Kallikrein-Kinin System (KKS) has been found to play a role in tumor progression in several cancers. The KKS metabolic cascade depends on signalling through two cross talking receptors; bradykinin receptor 1 (B1R) and bradykinin receptor 2 (B2R). Activation of the Kinin receptor is responsible for multiple pathophysiologic functions including increase of vascular permeability and induction of host inflammatory responses that exert diverse effects on tumor growth. Methods B1R and B2R expression on mouse and human CRC cell lines was investigated. Changes in tumor growth and progression was assessed in male CBA mice bearing colorectal liver metastases (CRLM) following treatment with B1R or B2R blockers. In vitro cultures of human SW-480 and mouse colorectal cancer (MoCR) cell lines were examined for changes in their proliferation and migration properties following treatment with B1R or B2R blockers. Results Both colorectal cancer cell lines tested strongly positive for B1R and B2R expression. Inhibition of both receptors retarded tumor growth but only B1R blockade significantly reduced tumor load and increased tumor apoptosis. Blockade of either receptor reduced tumor vascularization in vivo and significantly inhibited proliferation and migration of colorectal cancer cells in vitro. Conclusion Taken together, the present study demonstrated that kinin receptor blockade inhibited tumor growth and reduced its invading properties suggesting that KKS manipulation could be a novel target in colorectal cancer therapy. Electronic supplementary material The online version of this article (10.1186/s12885-018-4260-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Patricia Luiza Nunes da Costa
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia.,Laboratório de Oncologia Experimental, Faculdade de Medicina da Universidade de São Paulo and Instituto do Câncer do Estado de São Paulo, São Paulo, Brazil
| | - David Wynne
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia
| | - Theodora Fifis
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia.
| | - Linh Nguyen
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia
| | - Marcos Perini
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia
| | - Christopher Christophi
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia
| |
Collapse
|
5
|
Nguyen L, Fifis T, Christophi C. Vascular disruptive agent OXi4503 and anti-angiogenic agent Sunitinib combination treatment prolong survival of mice with CRC liver metastasis. BMC Cancer 2016; 16:533. [PMID: 27460820 PMCID: PMC4962549 DOI: 10.1186/s12885-016-2568-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 07/14/2016] [Indexed: 11/29/2022] Open
Abstract
Background Preclinical research indicate that vascular disrupting agent (VDA) treatment induces extensive tumor death but also a systemic mobilization of bone marrow derived cells including endothelial progenitor cells (EPC) leading to revascularization and renewed growth within the residual tumor. This study investigates if combination of VDA with the anti-angiogenic agent Sunitinib increases the treatment efficacy in a colorectal liver metastases mouse model. Methods CBA mice with established liver metastases were given a single dose of OXi4503 at day 16 post tumor induction, a daily dose of Sunitinib starting at day 14 or day 16 post tumor induction or a combination of Sunitinib given daily from day 14 or day 16 post tumor induction in combination with a single dose of OXi4503 at day 16. Treatment was terminated at day 21 post tumor induction and its effects were assessed using stereological and immunohistochemical techniques. Long term effects were assessed in a survival study. Results Combination with long (7 day) Sunitinib treatment lead to liver toxicity but this was ameliorated in the shorter (5 day) treatment without significantly altering the effects on tumor reduction. Combination treatment resulted in significant reduction of viable tumor, reduction in tumor vasculature, reduction in tumor proliferation, increase in tumor apoptosis and prolonged mouse survival compared to control and single arm treatments. Complete tumor eradication was not achieved. Redistribution of E-cadherin and strong up regulation of ZEB1 and Vimentin were observed in the surviving tumor; indicative of epithelial to mesenchymal transition (EMT), a mechanism that could contribute to tumor resistance. Conclusions Combination treatment significantly reduces viable tumor and prolongs animal survival. EMT in the surviving tumor may prevent total tumor eradication and could provide novel targets for a more lasting treatment. Electronic supplementary material The online version of this article (doi:10.1186/s12885-016-2568-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Linh Nguyen
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia
| | - Theodora Fifis
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia.
| | - Christopher Christophi
- Department of Surgery, University of Melbourne, Austin Health, Lance Townsend Building Level 8, Studley Rd, Heidelberg, VIC, 3084, Australia
| |
Collapse
|
6
|
Liu G, Kuang S, Wu S, Jin W, Sun C. A novel polysaccharide from Sargassum integerrimum induces apoptosis in A549 cells and prevents angiogensis in vitro and in vivo. Sci Rep 2016; 6:26722. [PMID: 27216943 PMCID: PMC4877640 DOI: 10.1038/srep26722] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/09/2016] [Indexed: 12/13/2022] Open
Abstract
Many polysaccharides isolated from plants have exhibited promising antitumor activities. The aim of this study is to investigate the antitumor activity of the novel polysaccharide named SPS from Sargassum integerrimum, elucidate the underlying anticancer mechanism in a human lung cancer cell line A549, and evaluate its anti-angiogenic activity both in vitro and in vivo. The results show that SPS significantly reduces A549 cells viability in a dose- and time-dependent manner via MTT method. Flow cytometry analysis indicates that SPS could induce cell apoptosis, the loss of mitochondrial membrane potential (MMP), generation of reactive oxygen species (ROS) and G2/M phase cell cycle arrest of A549 cells. Up-regulation of the expressions of P53 and Bax, down-regulation of the expression of Bcl-2, and activation of cleaved caspase-3, caspase-9 and PARP are also detected by western blotting after the treatment of SPS. In addition, SPS inhibits the proliferation, migration and cord formation of human umbilical vein endothelial cells (HUVECs) in vitro, and prevents the vascular development of zebrafish embryos in vivo. Altogether, our data prove the anticancer and anti-angiogenesis properties of SPS, and provide further insights into the potential pharmacological application of SPS as antitumor and anti-angiogenic agent against lung cancer.
Collapse
Affiliation(s)
- Ge Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
- College of Earth Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shan Kuang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Shimei Wu
- Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Weihua Jin
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Chaomin Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| |
Collapse
|
7
|
Qi X, Liu G, Qiu L, Lin X, Liu M. Marine bromophenol bis(2,3-dibromo-4,5-dihydroxybenzyl) ether, represses angiogenesis in HUVEC cells and in zebrafish embryos via inhibiting the VEGF signal systems. Biomed Pharmacother 2015; 75:58-66. [PMID: 26463632 DOI: 10.1016/j.biopha.2015.08.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/23/2015] [Indexed: 02/02/2023] Open
Abstract
Bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (BDDE) is a bromophenol compound derived from marine algae. Our previous reports have shown that BDDE possessed anticancer activity in vitro. However, its antiangiogenesis activity and possible mechanisms remain unclear. The present study demonstrated that BDDE displayed in vitro antiangiogenesis capabilities by significantly inhibiting HUVEC cells proliferation, migration, and tube formation, without any effect on the preformed vascular tube. Western blot analysis revealed that BDDE decreased the protein level of VEGF and VEGFR but not that of EGFR, FGFR, and IGFR. In addition, BDDE inactivated the VEGF downstream signaling molecules including mTOR and Src, whereas activated Akt and ERK. Moreover, BDDE blocked subintestinal vessel formation in zebrafish embryos in vivo and showed toxicity under high concentrations of BDDE. The results of this present study indicated that BDDE, which has unique chemical structure different from current antiangiogenesis agents, could be used as a potential drug candidate for cancer prevention and therapy.
Collapse
Affiliation(s)
- Xin Qi
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Ge Liu
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Lin Qiu
- Institute for Nutritional Sciences, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiukun Lin
- Department of Pharmacology, Capital Medical University, Beijing 100069, China
| | - Ming Liu
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
| |
Collapse
|
8
|
Abstract
Since angiogenesis is critical for tumor growth and metastasis, anti-angiogenic treatment is a highly promising therapeutic approach. Thus, for over last couple of decades, there has been a robust activity aimed towards the discovery of angiogenesis inhibitors. More than forty anti-angiogenic drugs are being tested in clinical trials all over the world. This review discusses agents that have approved by the FDA and are currently in use for treating patients either as single-agents or in combination with other chemotherapeutic agents.
Collapse
Affiliation(s)
- Rajeev S Samant
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA.
| | | |
Collapse
|
9
|
Rice L, Pampo C, Lepler S, Rojiani AM, Siemann DW. Support of a free radical mechanism for enhanced antitumor efficacy of the microtubule disruptor OXi4503. Microvasc Res 2010; 81:44-51. [PMID: 20974154 DOI: 10.1016/j.mvr.2010.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 10/14/2010] [Accepted: 10/15/2010] [Indexed: 01/03/2023]
Abstract
Unlike normal blood vessels, the unique characteristics of an expanding, disorganized and leaky tumor vascular network can be targeted for therapeutic gain by vascular disrupting agents (VDAs), which promote rapid and selective collapse of tumor vessels, causing extensive secondary cancer cell death. A hallmark observation following VDA treatment is the survival of neoplastic cells at the tumor periphery. However, comparative studies with the second generation tubulin-binding VDA OXi4503 indicate that the viable rim of tumor tissue remaining following treatment with this agent is significantly smaller than that seen for the lead VDA, combretastatin. OXi4503 is the cis-isomer of CA1P and it has been speculated that this agent's increased antitumor efficacy may be due to its reported metabolism to orthoquinone intermediates leading to the formation of cytotoxic free radicals. To examine this possibility in situ, KHT sarcoma-bearing mice were treated with either the cis- or trans-isomer of CA1P. Since both isomers can form quinone intermediates but only the cis-isomer binds tubulin, such a comparison allows the effects of vascular collapse to be evaluated independently from those caused by the reactive hydroxyl groups. The results showed that the cis-isomer (OXi4503) significantly impaired tumor blood flow leading to secondary tumor cell death and >95% tumor necrosis 24h post drug exposure. Treatment with the trans-isomer had no effect on these parameters. However, the combination of the trans-isomer with combretastatin increased the antitumor efficacy of the latter agent to near that of OXi4503. These findings indicate that while the predominant in vivo effect of OXi4503 is clearly due to microtubule collapse and vascular shut-down, the formation of toxic free radicals likely contributes to its enhanced potency.
Collapse
Affiliation(s)
- Lori Rice
- Department of Radiation Oncology, University of Florida, Gainesville, FL 32610, USA.
| | | | | | | | | |
Collapse
|