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Leal AS, Hung PY, Chowdhury AS, Liby KT. Retinoid X Receptor agonists as selective modulators of the immune system for the treatment of cancer. Pharmacol Ther 2023; 252:108561. [PMID: 37952906 DOI: 10.1016/j.pharmthera.2023.108561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/28/2023] [Accepted: 11/06/2023] [Indexed: 11/14/2023]
Abstract
Upon heterodimerizing with other nuclear receptors, retinoid X receptors (RXR) act as ligand-dependent transcription factors, regulating transcription of critical signaling pathways that impact numerous hallmarks of cancer. By controlling both inflammation and immune responses, ligands that activate RXR can modulate the tumor microenvironment. Several small molecule agonists of these essential receptors have been synthesized. Historically, RXR agonists were tested for inhibition of growth in cancer cells, but more recent drug discovery programs screen new molecules for inhibition of inflammation or activation of immune cells. Bexarotene is the first successful example of an effective therapeutic that molecularly targets RXR; this drug was approved to treat cutaneous T cell lymphoma and is still used as a standard of care treatment for this disease. No additional RXR agonists have yet achieved FDA approval, but several promising novel compounds are being developed. In this review, we provide an overview of the multiple mechanisms by which RXR signaling regulates inflammation and tumor immunity. We also discuss the potential of RXR-dependent immune cell modulation for the treatment or prevention of cancer and concomitant challenges and opportunities.
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Affiliation(s)
- Ana S Leal
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States of America; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Pei-Yu Hung
- Department of Physiology, Michigan State University, East Lansing, MI, United States of America
| | - Afrin Sultana Chowdhury
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Karen T Liby
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States of America; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States of America.
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Wu Y, Li Z, Wedn AM, Casey AN, Brown D, Rao SV, Omarjee S, Hooda J, Carroll JS, Gertz J, Atkinson JM, Lee AV, Oesterreich S. FOXA1 Reprogramming Dictates Retinoid X Receptor Response in ESR1-Mutant Breast Cancer. Mol Cancer Res 2023; 21:591-604. [PMID: 36930833 PMCID: PMC10239325 DOI: 10.1158/1541-7786.mcr-22-0516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 01/27/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023]
Abstract
Estrogen receptor alpha (ER/ESR1) mutations occur in 30% to 40% of endocrine resistant ER-positive (ER+) breast cancer. Forkhead box A1 (FOXA1) is a key pioneer factor mediating ER-chromatin interactions and endocrine response in ER+ breast cancer, but its role in ESR1-mutant breast cancer remains unclear. Our previous FOXA1 chromatin immunoprecipitation sequencing (ChIP-seq) identified a large portion of redistributed binding sites in T47D genome-edited Y537S and D538G ESR1-mutant cells. Here, we further integrated FOXA1 genomic binding profile with the isogenic ER cistrome, accessible genome, and transcriptome data of T47D cell model. FOXA1 redistribution was significantly associated with transcriptomic alterations caused by ESR1 mutations. Furthermore, in ESR1-mutant cells, FOXA1-binding sites less frequently overlapped with ER, and differential gene expression was less associated with the canonical FOXA1-ER axis. Motif analysis revealed a unique enrichment of retinoid X receptor (RXR) motifs in FOXA1-binding sites of ESR1-mutant cells. Consistently, ESR1-mutant cells were more sensitive to growth stimulation with the RXR agonist LG268. The mutant-specific response was dependent on two RXR isoforms, RXR-α and RXR-β, with a stronger dependency on the latter. In addition, T3, the agonist of thyroid receptor (TR) also showed a similar growth-promoting effect in ESR1-mutant cells. Importantly, RXR antagonist HX531 blocked growth of ESR1-mutant cells and a patient-derived xenograft (PDX)-derived organoid with an ESR1 D538G mutation. Collectively, our data support the evidence for a stronger RXR response associated with FOXA1 reprograming in ESR1-mutant cells, suggesting development of therapeutic strategies targeting RXR pathways in breast tumors with ESR1 mutation. IMPLICATIONS It provides comprehensive characterization of the role of FOXA1 in ESR1-mutant breast cancer and potential therapeutic strategy through blocking RXR activation.
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Affiliation(s)
- Yang Wu
- School of Medicine, Tsinghua University, Beijing, China
- Women’s Cancer Research Center, UPMC Hillman Cancer Center, Magee-Womens Research Institute, Pittsburgh PA, USA
| | - Zheqi Li
- Women’s Cancer Research Center, UPMC Hillman Cancer Center, Magee-Womens Research Institute, Pittsburgh PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh PA, USA
| | - Abdalla M. Wedn
- Women’s Cancer Research Center, UPMC Hillman Cancer Center, Magee-Womens Research Institute, Pittsburgh PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh PA, USA
| | - Allison N. Casey
- Women’s Cancer Research Center, UPMC Hillman Cancer Center, Magee-Womens Research Institute, Pittsburgh PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh PA, USA
| | - Daniel Brown
- Institute for Precision Medicine, University of Pittsburgh, Pittsburgh PA, USA
| | - Shalini V. Rao
- Cancer Research UK, Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Soleilmane Omarjee
- Cancer Research UK, Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Jagmohan Hooda
- Women’s Cancer Research Center, UPMC Hillman Cancer Center, Magee-Womens Research Institute, Pittsburgh PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh PA, USA
| | - Jason S. Carroll
- Cancer Research UK, Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Jason Gertz
- Department of Oncological Sciences, University of Utah, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Jennifer M. Atkinson
- Women’s Cancer Research Center, UPMC Hillman Cancer Center, Magee-Womens Research Institute, Pittsburgh PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh PA, USA
- Institute for Precision Medicine, University of Pittsburgh, Pittsburgh PA, USA
| | - Adrian V. Lee
- Women’s Cancer Research Center, UPMC Hillman Cancer Center, Magee-Womens Research Institute, Pittsburgh PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh PA, USA
- Institute for Precision Medicine, University of Pittsburgh, Pittsburgh PA, USA
| | - Steffi Oesterreich
- Women’s Cancer Research Center, UPMC Hillman Cancer Center, Magee-Womens Research Institute, Pittsburgh PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh PA, USA
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Zou C, Wang L, Shu C, Tan X, Wu Z, Zou Y, Li Z, Wang G, Song Z, You F. Rxrs and their partner receptor genes inducing masculinization plausibly mediated by endocrine disruption in Paralichthys olivaceus. J Steroid Biochem Mol Biol 2023; 226:106219. [PMID: 36356854 DOI: 10.1016/j.jsbmb.2022.106219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 11/03/2022] [Accepted: 11/06/2022] [Indexed: 11/09/2022]
Abstract
Retinoid X receptors (RXRs) can form homo- or heterodimers with orphan receptors involved in multiple intertwined signaling pathways. However, there is limited study on the formation of sex phenotypes and the regulation of steroidogenesis by RXRs in fish. Here, in Paralichthys olivaceus, we first indicated that PPARγ::RXRα was predictably a transcription factor for steroidogenesis genes, and Foxl2 and Dmrt1 were also transcription factors for rxrs and their partner receptor genes. When the flounder fry were exposed to LG100268 (LG, RXRs agonist, 50 mg/kg diet), the percentage of males increased from 50% to 71.4%. Before histological differentiation of the flounder ovary (3 cm TL) and testis (6 cm TL), the transcripts of rar β and rar γ (P < 0.05) were activated, and the steroidogenesis gene Hsd3b1 was down-regulated (P < 0.05). The ratios of testosterone (T)/17β-estradiol (E2) were all greatly increased (P < 0.05), and the ratio of 11-ketotestosterone (11-KT)/E2 was elevated at 3 cm TL. Moreover, LG was used to treat the cultured gonads in vitro (10 μM) and the fish with intraperitoneal injection in vivo (12 mg/kg body weight), respectively. LG was able to up-regulate rxr γ, rar γ, and ppar δ, and Hsd3b1 was significantly up-regulated (P < 0.05). The ratios of 11-KT/E2 in the culture medium and in the ovaries of the fish were decreased. Furthermore, the recombinant flounder Foxl2 protein was able to significantly down-regulate ppar γ (P < 0.05) and tr β (P < 0.01) in the ovaries in vitro, and the result of the Dmrt1 in the testes was opposite to that of the Foxl2, probably indicating a feedback loop between RXRs' partner receptors and Foxl2/Dmrt1. These findings introduce for the first time the mode of action of RXRs on the flounder steroidogenesis and provide important data to learn the potential function of RXRs in fish sex differentiation and the potential role of RXRs in aquatic animals in the presence of water pollutants.
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Affiliation(s)
- Congcong Zou
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Lijuan Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China
| | - Chang Shu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xungang Tan
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China
| | - Zhihao Wu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China
| | - Yuxia Zou
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China
| | - Ze Li
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Guoyu Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China
| | - Zongcheng Song
- Shenghang Aquatic Science and Technology Co. Ltd., Weihai 264200, PR China
| | - Feng You
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, PR China.
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Leal AS, Reich LA, Moerland JA, Zhang D, Liby KT. Potential therapeutic uses of rexinoids. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2021; 91:141-183. [PMID: 34099107 DOI: 10.1016/bs.apha.2021.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The discovery of nuclear receptors, particularly retinoid X receptors (RXR), and their involvement in numerous pathways related to development sparked interest in their immunomodulatory properties. Genetic models using deletion or overexpression of RXR and the subsequent development of several small molecules that are agonists or antagonists of this receptor support a promising therapeutic role for these receptors in immunology. Bexarotene was approved in 1999 for the treatment of cutaneous T cell lymphoma. Several other small molecule RXR agonists have since been synthesized with limited preclinical development, but none have yet achieved FDA approval. Cancer treatment has recently been revolutionized with the introduction of immune checkpoint inhibitors, but their success has been restricted to a minority of patients. This review showcases the emerging immunomodulatory effects of RXR and the potential of small molecules that target this receptor as therapies for cancer and other diseases. Here we describe the essential roles that RXR and partner receptors play in T cells, dendritic cells, macrophages and epithelial cells, especially within the tumor microenvironment. Most of these effects are site and cancer type dependent but skew immune cells toward an anti-inflammatory and anti-tumor effect. This beneficial effect on immune cells supports the promise of combining rexinoids with approved checkpoint blockade therapies in order to enhance efficacy of the latter and to delay or potentially eliminate drug resistance. The data compiled in this review strongly suggest that targeting RXR nuclear receptors is a promising new avenue in immunomodulation for cancer and other chronic inflammatory diseases.
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Affiliation(s)
- Ana S Leal
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | - Lyndsey A Reich
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | - Jessica A Moerland
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | - Di Zhang
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | - Karen T Liby
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States.
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Mohammed A, Fox JT, Miller MS. Cancer Chemoprevention: Preclinical In Vivo Alternate Dosing Strategies to Reduce Drug Toxicities. Toxicol Sci 2019; 170:251-259. [PMID: 31020311 PMCID: PMC6657562 DOI: 10.1093/toxsci/kfz104] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cancer chemopreventive agents inhibit the formation of precursor lesions and/or the progression of these lesions to late stage disease. This approach to disease control has the potential to reduce the physical and financial costs of cancer in society. Several drugs that have been approved by the FDA for other diseases and have been extensively evaluated for their safety and pharmacokinetic/pharmacodynamic characteristics have the potential to be repurposed for use as cancer chemopreventive agents. These agents often mechanistically inhibit signaling molecules that play key roles in the carcinogenic process. The safety profile of agents is a primary concern when considering the administration of drugs for chemoprevention, as the drugs will be given chronically to high-risk, asymptomatic individuals. To decrease drug toxicity while retaining efficacy, several approaches are currently being explored. In this short review, we describe studies that use preclinical in vivo models to assess efficacy of alternative drug dosing strategies and routes of drug administration on chemopreventive drug efficacy. In vivo drug dosing strategies that reduce toxicity while retaining efficacy will pave the way for future cancer prevention clinical trials.
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Affiliation(s)
- Altaf Mohammed
- Chemopreventive Agent Development Research Group, Division of Cancer Prevention, National Cancer Institute, Rockville, Maryland
| | - Jennifer T Fox
- Chemopreventive Agent Development Research Group, Division of Cancer Prevention, National Cancer Institute, Rockville, Maryland
| | - Mark Steven Miller
- Chemopreventive Agent Development Research Group, Division of Cancer Prevention, National Cancer Institute, Rockville, Maryland
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Zhang D, Leal AS, Carapellucci S, Shahani PH, Bhogal JS, Ibrahim S, Raban S, Jurutka PW, Marshall PA, Sporn MB, Wagner CE, Liby KT. Testing Novel Pyrimidinyl Rexinoids: A New Paradigm for Evaluating Rexinoids for Cancer Prevention. Cancer Prev Res (Phila) 2019; 12:211-224. [PMID: 30760500 DOI: 10.1158/1940-6207.capr-18-0317] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/10/2018] [Accepted: 02/04/2019] [Indexed: 11/16/2022]
Abstract
Rexinoids, selective ligands for retinoid X receptors (RXR), have shown promise in preventing many types of cancer. However, the limited efficacy and undesirable lipidemic side-effects of the only clinically approved rexinoid, bexarotene, drive the search for new and better rexinoids. Here we report the evaluation of novel pyrimidinyl (Py) analogues of two known chemopreventive rexinoids, bexarotene (Bex) and LG100268 (LG268) in a new paradigm. We show that these novel derivatives were more effective agents than bexarotene for preventing lung carcinogenesis induced by a carcinogen. In addition, these new analogues have an improved safety profile. PyBex caused less elevation of plasma triglyceride levels than bexarotene, while PyLG268 reduced plasma cholesterol levels and hepatomegaly compared with LG100268. Notably, this new paradigm mechanistically emphasizes the immunomodulatory and anti-inflammatory activities of rexinoids. We reveal new immunomodulatory actions of the above rexinoids, especially their ability to diminish the percentage of macrophages and myeloid-derived suppressor cells in the lung and to redirect activation of M2 macrophages. The rexinoids also potently inhibit critical inflammatory mediators including IL6, IL1β, CCL9, and nitric oxide synthase (iNOS) induced by lipopolysaccharide. Moreover, in vitro iNOS and SREBP (sterol regulatory element-binding protein) induction assays correlate with in vivo efficacy and toxicity, respectively. Our results not only report novel pyrimidine derivatives of existing rexinoids, but also describe a series of biological screening assays that will guide the synthesis of additional rexinoids. Further progress in rexinoid synthesis, potency, and safety should eventually lead to a clinically acceptable and useful new drug for patients with cancer.
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Affiliation(s)
- Di Zhang
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Ana S Leal
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Sarah Carapellucci
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Pritika H Shahani
- Arizona State University, School of Mathematical and Natural Sciences, Glendale, Arizona
| | - Jaskaran S Bhogal
- Arizona State University, School of Mathematical and Natural Sciences, Glendale, Arizona
| | - Samir Ibrahim
- Arizona State University, School of Mathematical and Natural Sciences, Glendale, Arizona
| | - San Raban
- Arizona State University, School of Mathematical and Natural Sciences, Glendale, Arizona
| | - Peter W Jurutka
- Arizona State University, School of Mathematical and Natural Sciences, Glendale, Arizona
| | - Pamela A Marshall
- Arizona State University, School of Mathematical and Natural Sciences, Glendale, Arizona
| | - Michael B Sporn
- Geisel School of Medicine at Dartmouth, Department of Pharmacology, Lebanon, New Hampshire
| | - Carl E Wagner
- Arizona State University, School of Mathematical and Natural Sciences, Glendale, Arizona
| | - Karen T Liby
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan.
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Lubet RA, Steele VE, Shoemaker RH, Grubbs CJ. Screening of Chemopreventive Agents in Animal Models: Results on Reproducibility, Agents of a Given Class, and Agents Tested During Tumor Progression. Cancer Prev Res (Phila) 2018; 11:595-606. [PMID: 30045934 PMCID: PMC6186395 DOI: 10.1158/1940-6207.capr-18-0084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/08/2018] [Accepted: 07/17/2018] [Indexed: 12/22/2022]
Abstract
Because of the importance of testing reproducibility of results, we present our findings regarding screening agents in preclinical chemoprevention studies in rodent models performed by the Chemopreventive Agent Development Research Group (CADRG) of the Division of Cancer Prevention of the NCI. These studies were performed via contracts to various commercial and academic laboratories. Primarily, results with positive agents are reported because positive agents may progress to the clinics. In testing reproducibility, a limited number of direct repeats of our standard screening assays were performed; which entailed initiating treatment shortly after carcinogen administration or in young transgenic mice and continuing treatment until the end of the study. However, three additional protocols were employed relating to reproducibility: (i) testing agents at lower doses to determine efficacy and reduced toxicity; (ii) testing agents later in tumor progression when microscopic lesions existed and, (iii) testing multiple agents of the same mechanistic class. Data with six models that were routinely employed are presented: MNU-induced ER-positive mammary cancer in rats; MMTV-Neu ER-negative mammary cancers in transgenic mice; AOM-induced colon tumors in rats; intestinal adenomas in Min mice; OH-BBN-induced invasive rat urinary bladder cancers in rats; and UV-induced skin squamous carcinomas in mice. It was found that strongly positive results were highly reproducible in the preclinical models evaluated. Cancer Prev Res; 11(10); 595-606. ©2018 AACR.
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Affiliation(s)
- Ronald A Lubet
- Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland
| | - Vernon E Steele
- Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland
| | - Robert H Shoemaker
- Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland
| | - Clinton J Grubbs
- Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama.
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Axelrod DE, Bravo R. Chemoprevention of colon cancer: advantage of intermittent pulse treatment schedules quantified by computer simulation of human colon crypts. CONVERGENT SCIENCE PHYSICAL ONCOLOGY 2017. [DOI: 10.1088/2057-1739/aa82e6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chandra S, Nymeyer AC, Rice PF, Gerner EW, Barton JK. Intermittent Dosing with Sulindac Provides Effective Colorectal Cancer Chemoprevention in the Azoxymethane-Treated Mouse Model. Cancer Prev Res (Phila) 2017; 10:459-466. [PMID: 28611038 DOI: 10.1158/1940-6207.capr-17-0038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 05/17/2017] [Accepted: 06/09/2017] [Indexed: 01/05/2023]
Abstract
Sulindac is an NSAID that can provide effective chemoprevention for colorectal cancer. In this study, alternative dosing regimens of sulindac were evaluated for their chemoprevention effectiveness in the azoxymethane-treated A/J mouse model of colorectal cancer. High-resolution endoscopic optical coherence tomography was utilized to time-serially measure tumor number and tumor burden in the distal colon as the biological endpoints. Four treatment groups were studied: (i) daily for 20 weeks (sulindac-daily); (ii) for 2 weeks, then no sulindac for 2 weeks, cycle repeated 5 times (sulindac-2); (iii) for 10 weeks ("on"), then no sulindac for 10 weeks ("off"; sulindac-10); and (iv) no sulindac (sulindac-none). Sulindac-2 and sulindac-daily had statistically significantly lower final tumor counts and slopes (change in number of tumors per week) when compared with sulindac-none (P < 0.0001). All of the treatment groups had statistically significantly lower final tumor burdens and slopes when compared with sulindac-none (P < 0.001). There was a prolonged latency period in the sulindac-10 group, with no significant difference between the "off" portion of this treatment and sulindac-none. These results suggest that, although daily doses of sulindac provide the most optimal effects, intermittent doses of sulindac in a 50% duty cycle with an overall 4-week period (sulindac-2 model) can provide highly effective chemoprevention of colorectal cancer in this model. After cessation of sulindac treatment (sulindac-10 "off"), there is no evidence of either a persistent chemopreventive effect or a rebound effect. Cancer Prev Res; 10(8); 459-66. ©2017 AACR.
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Affiliation(s)
- Swati Chandra
- Biomedical Engineering, University of Arizona, Tucson, Arizona
| | - Ariel C Nymeyer
- Biomedical Engineering, University of Arizona, Tucson, Arizona
| | | | - Eugene W Gerner
- Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona.,Cancer Prevention Pharmaceuticals, Tucson, Arizona
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Xu T, Zhong L, Gan LG, Xiao CL, Shan ZL, Yang R, Song H, Li L, Liu BZ. Effects of LG268 on Cell Proliferation and Apoptosis of NB4 Cells. Int J Med Sci 2016; 13:517-23. [PMID: 27429588 PMCID: PMC4946122 DOI: 10.7150/ijms.15507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/12/2016] [Indexed: 12/28/2022] Open
Abstract
AIMS To investigate the effect of LG100268 (LG268) on cell proliferation and apoptosis in NB4 cells. METHODS NB4 cells were treated with LG268 for 24 h or 48 h. The effect of LG268 on cell proliferation was assessed by the CCK-8 assay and colony-forming assay. Apoptosis and cell cycle were evaluated by flow cytometry. The protein expression levels of Survivin, PARP, c-Myc, cyclin D1, ERK, p-ERK, p38 MAPK, and p- p38 MAPK were detected by western blot. RESULTS We found that LG268 inhibited the proliferation of NB4 cells in a dose-dependent manner. Flow cytometry analysis showed that LG268 accelerated apoptosis in NB4 cells in a time- dependent manner and that LG268 treatment led to cell cycle arrest at G0/G1 phase. Moreover, LG268 significantly decreased the protein levels of Survivin, c-Myc, and cyclinD1. Cleaved PARP was observed in the LG268 treatment group but not in the control group. In addition, LG268 increased the phosphorylation level of p38 MAPK and decreased the phosphorylation level of ERK. CONCLUSIONS LG268 inhibited cell proliferation and promoted cell apoptosis in NB4 cells.
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Affiliation(s)
- Ting Xu
- 1. Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, 402160, China; 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Liang Zhong
- 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Liu-Gen Gan
- 1. Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, 402160, China; 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Chun-Lan Xiao
- 1. Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, 402160, China; 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Zhi-Ling Shan
- 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Rong Yang
- 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Hao Song
- 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Liu Li
- 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Bei-Zhong Liu
- 1. Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, 402160, China; 2. Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
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The Rexinoids LG100268 and LG101506 Inhibit Inflammation and Suppress Lung Carcinogenesis in A/J Mice. Cancer Prev Res (Phila) 2015; 9:105-14. [DOI: 10.1158/1940-6207.capr-15-0325] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/03/2015] [Indexed: 11/16/2022]
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Abstract
Pharmacologic interventions for cancer risk reduction involve the chronic administration of synthetic or natural agents to reduce or delay the occurrence of malignancy. Despite the strong evidence for a favorable risk-benefit ratio for a number of agents in several common malignancies such as breast and prostate cancer, the public's attitude toward cancer chemoprevention remains ambivalent, with the issue of toxicity associated with drugs being perceived as the main barrier to widespread use of preventive therapy by high-risk subjects. Among the strategies to overcome such obstacles to preventive therapies, two novel and potentially safer modes of administering agents are discussed in this paper. The first strategy is to lower the dose of drugs that are in common use in the adjuvant setting based on the notion that prevention of cancer cells from developing should require a lower dose than eradicating established tumor cells. A second approach is to adopt an intermittent administration similar to what is used in the chemotherapy setting in an attempt to minimize risks while retaining benefits. This article provides a detailed discussion of the principles and future development of these two approaches in the direction of a precision preventive medicine.
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Affiliation(s)
- Matteo Lazzeroni
- Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy.
| | - Andrea DeCensi
- Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy; Division of Medical Oncology, E.O. Ospedali Galliera, Genoa, Italy
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To C, Kim EH, Royce DB, Williams CR, Collins RM, Risingsong R, Sporn MB, Liby KT. The PARP inhibitors, veliparib and olaparib, are effective chemopreventive agents for delaying mammary tumor development in BRCA1-deficient mice. Cancer Prev Res (Phila) 2014; 7:698-707. [PMID: 24817481 DOI: 10.1158/1940-6207.capr-14-0047] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Poly-ADP ribose polymerase (PARP) inhibitors are effective for the treatment of BRCA-deficient tumors. Women with these mutations have an increased risk of developing breast cancer and would benefit from effective chemoprevention. This study examines whether the PARP inhibitors, veliparib and olaparib, delay mammary gland tumor development in a BRCA1-deficient (BRCA1(Co/Co);MMTV-Cre;p53(+/-)) mouse model. In dose de-escalation studies, mice were fed with control, veliparib (100 mg/kg diet), or olaparib (200, 100, 50, or 25 mg/kg diet) continuously for up to 43 weeks. For intermittent dosing studies, mice cycled through olaparib (200 mg/kg diet) for 2 weeks followed by a 4-week rest period on control diet. To examine biomarkers, mice were fed with olaparib using the intermittent dosing regimen and mammary glands were evaluated by immunohistochemistry. In mice treated with veliparib or olaparib (200 mg/kg diet), the average age of the first detectable tumor was delayed by 2.4 and 6.5 weeks, respectively, compared with controls. Olaparib also increased the average lifespan of mice by 7 weeks. In dose de-escalation studies, lower concentrations of olaparib delayed tumor development but were less effective than the highest dose. When fed intermittently, olaparib delayed the onset of the first palpable tumor by 5.7 weeks and significantly reduced proliferation and induced apoptosis in hyperplastic mammary glands. In summary, veliparib and olaparib are effective for delaying tumor development and extending the lifespan of BRCA1-deficient mice, and intermittent dosing with olaparib was as effective as continuous dosing. These results suggest that the use of PARP inhibitors is a promising chemopreventive option.
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Affiliation(s)
- Ciric To
- Authors' Affiliations: Departments of Pharmacology, and
| | - Eun-Hee Kim
- Authors' Affiliations: Departments of Pharmacology, and
| | | | | | | | | | | | - Karen T Liby
- Authors' Affiliations: Departments of Pharmacology, and Medicine, Dartmouth Medical School, Hanover, New Hampshire
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Burris TP, Solt LA, Wang Y, Crumbley C, Banerjee S, Griffett K, Lundasen T, Hughes T, Kojetin DJ. Nuclear receptors and their selective pharmacologic modulators. Pharmacol Rev 2013; 65:710-78. [PMID: 23457206 PMCID: PMC11060414 DOI: 10.1124/pr.112.006833] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Nuclear receptors are ligand-activated transcription factors and include the receptors for steroid hormones, lipophilic vitamins, sterols, and bile acids. These receptors serve as targets for development of myriad drugs that target a range of disorders. Classically defined ligands that bind to the ligand-binding domain of nuclear receptors, whether they are endogenous or synthetic, either activate receptor activity (agonists) or block activation (antagonists) and due to the ability to alter activity of the receptors are often termed receptor "modulators." The complex pharmacology of nuclear receptors has provided a class of ligands distinct from these simple modulators where ligands display agonist/partial agonist/antagonist function in a tissue or gene selective manner. This class of ligands is defined as selective modulators. Here, we review the development and pharmacology of a range of selective nuclear receptor modulators.
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Affiliation(s)
- Thomas P Burris
- The Scripps Research Institute, 130 Scripps Way 2A1, Jupiter, FL 33458, USA.
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Abstract
Cancer chemoprevention approaches generally use long-term, continuous treatment, which can produce major preventive effects but which can also have unexpected serious adverse events. This raises the question of whether intermittent dosing schedules might reduce toxicity while retaining benefit, a concept that we call short-term intermittent therapy to eliminate premalignancy (SITEP). Recent preclinical studies support a novel SITEP approach whereby short-term, intermittent therapy eliminates premalignant cells via apoptosis that is induced by synthetic lethal interactions. Synthetic lethality allows personalized, selective elimination of premalignant clones without harming normal cells. This Opinion article provides a detailed discussion of the principle, method and future development of the SITEP approach.
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Affiliation(s)
- Xiangwei Wu
- Departments of Clinical Cancer Prevention, and Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
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Kim EH, Deng CX, Sporn MB, Liby KT. CDDO-imidazolide induces DNA damage, G2/M arrest and apoptosis in BRCA1-mutated breast cancer cells. Cancer Prev Res (Phila) 2011; 4:425-34. [PMID: 21372041 DOI: 10.1158/1940-6207.capr-10-0153] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Breast cancer-associated gene 1 (BRCA1) protein plays important roles in DNA damage and repair, homologous recombination, cell-cycle regulation, and apoptosis. The synthetic triterpenoid 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Imidazolide, CDDO-Im) is a promising anticancer and chemopreventive agent with potent antiproliferative and apoptotic activities against a wide variety of cancer types. However, the mechanisms responsible for the selective apoptotic effects of CDDO-Im in cancer cells remain elusive. In the present work, CDDO-Im induced G2/M arrest and apoptosis in BRCA1-mutated mammary tumor cell lines. Prior to the induction of apoptosis, CDDO-Im induced DNA damage and the phosphorylation of H2AX followed by activation of the DNA damage response. Moreover, CDDO-Im also induced the generation of reactive oxygen species (ROS), which is associated with the induction of DNA damage, in both mouse and human tumor cells containing a BRCA1 mutation. The inhibition of ROS generation by uric acid prevented the induction of DNA damage by CDDO-Im. Furthermore, treatment with CDDO-Im did not induce ROS in nonmalignant MCF-10A breast epithelial cells or in E18-14C-27 breast cancer cells with wild-type BRCA1 genes and was not cytotoxic to normal mouse 3T3 fibroblasts, highlighting a selective therapeutic potential of CDDO-Im for BRCA1-associated breast cancer cells. Altogether, our results show that CDDO-Im induces ROS and subsequent DNA damage, thereby facilitating the activation of the DNA damage checkpoint, G2/M arrest, and finally apoptosis in BRCA1-mutated cancer cells. The particular relevance of these findings to the chemoprevention of cancer is discussed. Cancer Prev Res; 4(3); 425-34. ©2011 AACR.
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Affiliation(s)
- Eun-Hee Kim
- Department of Pharmacology, Dartmouth Medical School, Hanover, NH, USA
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Uray IP, Brown PH. Chemoprevention of hormone receptor-negative breast cancer: new approaches needed. Recent Results Cancer Res 2011; 188:147-162. [PMID: 21253797 PMCID: PMC3415693 DOI: 10.1007/978-3-642-10858-7_13] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Results from clinical trials have demonstrated that it is possible to prevent estrogen-responsive breast cancers by targeting the estrogen receptor with selective estrogen receptor modulators (SERMs) (tamoxifen, raloxifene, or lasofoxifene) or with aromatase inhibitors (AIs) (anastrozole, letrozole, or exemestene). Results from breast cancer treatment trials suggest that aromatase inhibitors may be even more effective in preventing breast cancer than SERMs. However, while SERMs and aromatase inhibitors do prevent the development of many ER-positive breast cancers, these drugs do not prevent ER-negative breast cancer. These results show that new approaches are needed for the prevention of this aggressive form of breast cancer. Our laboratory and clinical efforts have been focused on identifying critical molecular pathways in breast cells that can be targeted for the prevention of ER-negative breast cancer. Our preclinical studies have demonstrated that other nuclear receptors, such as RXR receptors, vitamin D receptors, as well as others are critical for the growth of ER-negative breast cells and for the transformation of these cells into ER-negative cancers. Other studies show that growth factor pathways including those activated by EGFR, Her2, and IGFR, which are activated in many ER-negative breast cancers, can be targeted for the prevention of ER-negative breast cancer in mice. Clinical studies have also shown that PARP inhibitors are effective for the treatment of breast cancers arising in BRCA-1 or -2 mutation carriers, suggesting that targeting PARP may also be useful for the prevention of breast cancers arising in these high-risk individuals. Most recently, we have demonstrated that ER-negative breast cancers can be subdivided into four distinct groups based on the kinases that they express. These groups include ER-negative/Her-2-positive groups (the MAPK and immunomodulatory groups) and ER-negative/Her2-negative groups (the S6K and the cell cycle checkpoint groups). These groups of ER-negative breast cancers can be targeted with kinase inhibitors specific for each subgroup. These preclinical studies have supported the development of several clinical trials testing targeted agents for the prevention of breast cancer. The results of a completed Phase II cancer prevention trial using the RXR ligand bexarotene in women at high risk of breast cancer will be reviewed, and the current status of an ongoing Phase II trial using the EGFR and Her2 kinase inhibitor lapatinib for the treatment of women with DCIS breast cancer will be presented. It is anticipated that in the future these molecularly targeted drugs will be combined with hormonal agents such as SERMs or aromatase inhibitors to prevent all forms of breast cancer.
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Affiliation(s)
- Iván P Uray
- Department of Clinical Cancer Prevention, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77230, USA
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Theodosiou M, Laudet V, Schubert M. From carrot to clinic: an overview of the retinoic acid signaling pathway. Cell Mol Life Sci 2010; 67:1423-45. [PMID: 20140749 PMCID: PMC11115864 DOI: 10.1007/s00018-010-0268-z] [Citation(s) in RCA: 229] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 01/06/2010] [Accepted: 01/11/2010] [Indexed: 01/23/2023]
Abstract
Vitamin A is essential for the formation and maintenance of many body tissues. It is also important for embryonic growth and development and can act as a teratogen at critical periods of development. Retinoic acid (RA) is the biologically active form of vitamin A and its signaling is mediated by the RA and retinoid X receptors. In addition to its role as an important molecule during development, RA has also been implicated in clinical applications, both as a potential anti-tumor agent as well as for the treatment of skin diseases. This review presents an overview of how dietary retinoids are converted to RA, hence presenting the major players in RA metabolism and signaling, and highlights examples of treatment applications of retinoids. Moreover, we discuss the origin and diversification of the retinoid pathway, which are important factors for understanding the evolution of ligand-specificity among retinoid receptors.
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Affiliation(s)
- Maria Theodosiou
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon (Université Lyon 1, CNRS, INRA, Ecole Normale Supérieure de Lyon), 46 allée d'Italie, 69364 Lyon Cedex 07, France.
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Nath A, Sitruk-Ware R. Pharmacology and clinical applications of selective estrogen receptor modulators. Climacteric 2009; 12:188-205. [PMID: 19387883 DOI: 10.1080/13697130802657896] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Compounds that can be described as selective estrogen receptor modulators (SERMs) have expanded dramatically over the past two decades. The ability of SERMs to act as estrogens in certain tissues while remaining inert or acting as an anti-estrogen in other tissues has opened up opportunities for treating specific estrogen-modulated diseases without accepting the risk of systemic estrogen activity. SERM development has resulted in significant therapeutic advances for breast cancer, osteoporosis and potentially other diseases associated with the menopause. After the publication of the Women's Health Initiative, interest in compound selectivity that reduces menopausal symptoms while protecting bone, breast, uterus and the heart has increased. Future SERMs may also have a therapeutic profile that can be tailored to specific patient populations, including men. This review paper summarizes the characteristics of different SERMs from various pharmacological categories and the feasibility and scope of their use for a large range of disease/health conditions.
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Affiliation(s)
- A Nath
- Population Council, New York, NY 10065, USA
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Sharma A, Belna J, Espat J, Rodriguez G, Cannon VT, Hurteau JA. Effects of omega-3 fatty acids on components of the transforming growth factor beta-1 pathway: implication for dietary modification and prevention in ovarian cancer. Am J Obstet Gynecol 2009; 200:516.e1-6. [PMID: 19268879 DOI: 10.1016/j.ajog.2008.12.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 10/06/2008] [Accepted: 12/20/2008] [Indexed: 11/30/2022]
Abstract
OBJECTIVE We previously demonstrated that omega-3 fatty acids (OM-3FAs) have definitive inhibitory effects on ovarian cancer cell lines. We sought to determine whether the inhibitory effects of OM-3FAs were mediated by the transforming growth factor (TGF)-beta1 signaling pathway. STUDY DESIGN Ovarian cancer cell lines were grown at 37 degrees C in 5% CO(2) and treated with OM-3FAs, omega-6 fatty acids, and control at different concentrations for 24-72 hours. Enzyme-linked immunosorbent assay (ELISA) assay and Western blot analysis were used to measure TGF-beta1, phosphorylated mothers against decapentaplegic (Smad)-3 and p21 protein levels. RESULTS An ELISA assay demonstrated that OM-3FA treatment increased TGF-beta1 in all 3 Hey cell lines (P < .05). In both SKOV-3 and OVCAR-3 cells, TGF-beta1 levels were not significantly increased. Western blots confirmed increases in TGF-beta1, Smad-3 and p21 protein levels in Hey and HeyC2 but not SKOV-3 and OVCAR-3 cells. CONCLUSION OM-3FAs increased the level of TGF-beta1, Smad-3, and p21 protein in ovarian cancer cells known to be more sensitive to their inhibitory effect.
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Affiliation(s)
- Arun Sharma
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Illinois Medical Center at Chicago, Chicago, IL, USA
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Gómez E, Rodríguez A, Muñoz M, Caamaño JN, Carrocera S, Martín D, Facal N, Díez C. Development and quality of bovine morulae cultured in serum-free medium with specific retinoid receptor agonists. Reprod Fertil Dev 2009; 20:884-91. [PMID: 19007552 DOI: 10.1071/rd08103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Accepted: 08/08/2008] [Indexed: 12/20/2022] Open
Abstract
Retinoids regulate development and differentiation of the bovine blastocyst in vitro, although the underlying mechanisms remain to be clarified. A challenge in reproductive biotechnology is the identification of pathways that regulate early embryonic development and their influence on blastocyst differentiation, apoptosis and survival to cryopreservation as traits of embryo quality. The present paper analyses the effects of short-term exposure (24 h) to retinoids on in vitro-produced bovine morulae. Immature cumulus oocyte complexes were in vitro matured and fertilised. Presumptive zygotes were subsequently cultured in modified synthetic oviduct fluid up to Day 6, in which morulae were randomly allocated to the different experimental groups. The treatments consisted of 0.1 microM LG100268 (LG; a retinoid X receptor agonist), 0.7 microM all-trans retinoic acid (ATRA; a retinoic acid receptor agonist) or no additives. Day 8 blastocyst development was increased in the ATRA-treated group compared with the LG and untreated embryos. In Day 7 embryos, the number of total cells and cells allocated to the trophectoderm were higher in the ATRA-treated group compared with untreated embryos. Apoptosis in the inner cell mass increased after LG treatment, whereas ATRA had no effect. After vitrification and warming, survival and hatching rates of Day 7 blastocysts did not change with retinoid treatment. Within the LG-treated and untreated blastocyst groups, survival and hatching rates were higher for Day 7 than Day 8 embryos; however, Day 8 blastocysts treated with ATRA showed improved hatching rates. In conclusion, treatment of morulae with ATRA in serum-free medium improves embryo development and quality without increasing the incidence of apoptosis and necrosis.
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Pérez-Rodríguez S, Ortiz MA, Pereira R, Rodríguez-Barrios F, de Lera AR, Piedrafita FJ. Highly twisted adamantyl arotinoids: synthesis, antiproliferative effects and RXR transactivation profiles. Eur J Med Chem 2009; 44:2434-46. [PMID: 19216008 DOI: 10.1016/j.ejmech.2009.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 12/20/2008] [Accepted: 01/09/2009] [Indexed: 12/23/2022]
Abstract
Retinoid-related molecules with an adamantyl group (adamantyl arotinoids) have been described with selective activities towards the retinoid receptors as agonists for NR1B2 and NR1B3 (RARbeta,gamma) (CD437, MX3350-1) or RAR antagonists (MX781) that induce growth arrest and apoptosis in cancer cells. Since these molecules induce apoptosis independently of RAR transactivation, we set up to synthesize novel analogs with impaired RAR binding. Here we describe adamantyl arotinoids with 2,2'-disubstituted biaryl rings prepared using the Suzuki coupling of the corresponding fragments. Those with cinnamic and naphthoic acid end groups showed significant antiproliferative activity in several cancer cell lines, and this effect correlated with the induction of apoptosis as measured by caspase activity. Strikingly, some of these compounds, whereas devoid of RAR binding capacity, were able to activate RXR.
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Li Y, Brown PH. Strategies of hormonal prevention. Cancer Treat Res 2009; 147:1-35. [PMID: 21461832 DOI: 10.1007/978-0-387-09463-2_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Li Y, Zhang Y, Hill J, Kim HT, Shen Q, Bissonnette RP, Lamph WW, Brown PH. The rexinoid, bexarotene, prevents the development of premalignant lesions in MMTV-erbB2 mice. Br J Cancer 2008; 98:1380-8. [PMID: 18362934 PMCID: PMC2361704 DOI: 10.1038/sj.bjc.6604320] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Retinoids, vitamin A analogues that bind to retinoic acid receptor (RAR) or retinoid X receptor (RXR), play important roles in regulating cell proliferation, apoptosis, and differentiation. Recently, RXR-selective ligands, also referred to as rexinoids, have been investigated as potential chemopreventive agents for breast cancer. Our previous studies demonstrated that the rexinoid bexarotene significantly prevented ER-negative mammary tumourigenesis with less toxicity than naturally occurring retinoids in animal models. To determine whether bexarotene prevents cancer at the early stages during the multistage process of mammary carcinogenesis, we treated MMTV-erbB2 mice with bexarotene for 2 or 4 months. The development of preinvasive mammary lesions such as hyperplasias and carcinoma-in-situ was significantly inhibited. This inhibition was associated with reduced proliferation, but no induction of apoptosis. We also examined the regulation of a number of rexinoid-modulated genes including critical growth and cell cycle regulating genes using breast cell lines and mammary gland samples from mice treated with rexinoids. We showed that two of these genes (DHRS3 and DEC2) were modulated by bexarotene both in vitro and in vivo. Identification of these rexinoid-modulated genes will help us understand the mechanism by which rexinoid prevents cancer. Such rexinoid-regulated genes also represent potential biomarkers to assess the response of rexinoid treatment in clinical trials.
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Affiliation(s)
- Y Li
- Breast Center, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Rodriguez GC, Rimel B, Watkin W, Turbov JM, Barry C, Du H, Maxwell GL, Cline J. Progestin Treatment Induces Apoptosis and Modulates Transforming Growth Factor- in the Uterine Endometrium. Cancer Epidemiol Biomarkers Prev 2008; 17:578-84. [DOI: 10.1158/1055-9965.epi-07-0551] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Li Y, Zhang Y, Hill J, Shen Q, Kim HT, Xu X, Hilsenbeck SG, Bissonnette RP, Lamph WW, Brown PH. The Rexinoid LG100268 prevents the development of preinvasive and invasive estrogen receptor negative tumors in MMTV-erbB2 mice. Clin Cancer Res 2007; 13:6224-31. [PMID: 17947490 DOI: 10.1158/1078-0432.ccr-06-2681] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To test whether a novel rexinoid, LG100268, prevents the development of preinvasive and invasive estrogen receptor-negative mammary tumorigenesis in MMTV-erbB2 mice. EXPERIMENTAL DESIGN For invasive breast cancer prevention, MMTV-erbB2 mice were treated with daily gastric gavage of vehicle, LG100268 (10 mg/kg), or LG100268 (100 mg/kg) for long term starting at 3 months of age. For preinvasive lesion study, mice were treated with daily gastric gavage of vehicle or LG100268 (100 mg/kg) for 4 months. RESULTS Long-term treatment with LG100268 significantly prevented invasive mammary tumor development. Median time (age) to tumor development was delayed from 217 days in vehicle group to 357 days in low-dose group. In high-dose group, only 2 of 20 mice developed tumors after 430 days of treatment. Short-term treatment of LG100268 significantly prevented the development of preinvasive mammary lesions including hyperplasia and ductal carcinoma in situ. The cancer prevention effect was associated with reduced expression of Ki67 and cyclin D1 in mammary glands by >80%. CONCLUSION Rexinoid LG100268 is an effective chemopreventive agent in preventing the development of both malignant and premalignant mammary lesions in MMTV-erbB2 mice.
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Affiliation(s)
- Yuxin Li
- Breast Center, Department of Medicine, Baylor College of Medicine, Houston TX 77030, USA
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Liby K, Royce DB, Risingsong R, Williams CR, Wood MD, Chandraratna RA, Sporn MB. A new rexinoid, NRX194204, prevents carcinogenesis in both the lung and mammary gland. Clin Cancer Res 2007; 13:6237-43. [PMID: 17947492 DOI: 10.1158/1078-0432.ccr-07-1342] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE We evaluated the anti-inflammatory and growth-inhibitory properties of the novel rexinoid NRX194204 (4204) in vitro and then tested its ability to prevent and/or treat experimental lung and estrogen receptor (ER)-negative breast cancer in vivo. EXPERIMENTAL DESIGN In cell culture studies, we measured the ability of 4204 to block the effects of lipopolysaccharide and induce apoptosis. For the lung cancer prevention studies, A/J mice were injected with the carcinogen vinyl carbamate and then fed 4204 (30-60 mg/kg diet) for 15 weeks, beginning 1 week after the administration of the carcinogen. For breast cancer prevention studies, mouse mammary tumor virus-neu mice were fed control diet or 4204 (20 mg/kg diet) for 50 weeks; for treatment, tumors at least 32 mm3 in size were allowed to form, and then mice were fed control diet or 4204 (60 mg/kg diet) for 4 weeks. RESULTS Low nanomolar concentrations of 4204 blocked the ability of lipopolysaccharide and tumor necrosis factor-alpha to induce the release of nitric oxide and interleukin 6 and the degradation of IKBalpha in RAW264.7 macrophage-like cells. In the A/J mouse model of lung cancer, 4204 significantly (P < 0.05) reduced the number and size of tumors on the surface of the lungs and reduced the total tumor volume per slide by 64% to 81% compared with the control group. In mouse mammary tumor virus-neu mice, 4204 not only delayed the development of ER-negative mammary tumors in the prevention studies but also caused marked tumor regression (92%) or growth arrest (8%) in all of the mammary tumors when used therapeutically. CONCLUSIONS The combined anti-inflammatory and anticarcinogenic actions of 4204 suggest that it is a promising new rexinoid that should be considered for future clinical trials.
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Affiliation(s)
- Karen Liby
- Department of Pharmacology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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Affiliation(s)
- Louise R Howe
- Department of Cell and Developmental Biology, Weill Cornell Medical College, and Strang Cancer Research Laboratory, New York, New York 10065, USA.
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Li Y, Brown PH. Translational approaches for the prevention of estrogen receptor-negative breast cancer. Eur J Cancer Prev 2007; 16:203-15. [PMID: 17415091 DOI: 10.1097/cej.0b013e328011ed98] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Breast cancer prevention has focused heavily on endocrine interventions using selective estrogen receptor modulators and aromatase inhibitors. Tamoxifen, the stereotypical selective estrogen receptor modulator, significantly reduces the breast cancer incidence in high-risk women. Selective estrogen receptor modulators and aromatase inhibitors, however, only prevent the development of estrogen receptor-positive breast cancer and have no effect in reducing the risk of estrogen receptor-negative breast cancer, which has poor prognosis. Thus, preventive therapies for estrogen receptor-negative breast cancer are clearly needed. Recently, a number of novel chemopreventive agents targeting nonendocrine pathways have been developed and shown to prevent estrogen receptor-negative mammary tumorigenesis in animal models. These agents include rexinoids, selective cyclooxygenase-2 inhibitors, tyrosine kinase inhibitors, and others. In this review, we discuss the effects of selective estrogen receptor modulators and aromatase inhibitors, as well as novel agents targeting nonendocrine pathways. We also discuss the promise of combining these agents for the effective prevention of all forms of breast cancer.
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Affiliation(s)
- Yuxin Li
- Departments of Medicine and Molecular and Cellular Biology, Breast Center, Baylor College of Medicine, Houston, Texas 77030, USA
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Rodríguez A, Díez C, Caamaño JN, de Frutos C, Royo LJ, Muñoz M, Ikeda S, Facal N, Alvarez-Viejo M, Gómez E. Retinoid receptor-specific agonists regulate bovine in vitro early embryonic development, differentiation and expression of genes related to cell cycle arrest and apoptosis. Theriogenology 2007; 68:1118-27. [PMID: 17869331 DOI: 10.1016/j.theriogenology.2007.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Revised: 07/27/2007] [Accepted: 08/03/2007] [Indexed: 01/28/2023]
Abstract
A major goal in reproductive biotechnology is the identification of pathways that regulate early embryonic development and the allocation of cells to the inner cell mass (ICM) and trophectoderm (TE). Retinoids regulate the development and differentiation of the bovine blastocyst in vitro, although the involvement of the retinoid X receptors (RXRs) remains to be clarified. This paper compares the effect of a synthetic RXR agonist (LG100268; LG) with that of the retinoic acid receptor (RAR) agonist all-trans retinoic acid (ATRA) on blastulation. In vitro-produced morulae were treated for 48 h with LG (0.1 microM, 1 microM and 10 microM), ATRA 0.7 microM, or no additives. Treatment with ATRA did not increase the rate of development; however, the LG 0.1 microM treatment increased both the blastocyst development and hatching rate. Cell numbers increased in the ICM with LG 10 microM, while a dose-dependent reduction was observed in the TE in the presence of LG. Gene expression levels of p53 and p66 did not vary with LG but increased with ATRA. Both LG and ATRA activated bax, a pro-apoptotic gene and H2A.Z, a cell cycle-related gene. The above effects suggest the existence of active p53-dependent and -independent apoptotic pathways for ATRA and LG, respectively, in the bovine embryo. The expression of p53 and H2A.Z showed a strong, positive correlation (r=0.93; p<0.0001) in all experimental groups; both proteins are linked through the cell cycle. Agonists of RXR could be used to control blastocyst development and differentiation.
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Affiliation(s)
- A Rodríguez
- Genética y Reproducción SERIDA, Asturias, Spain
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31
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Hance KW, Rogers CJ, Hursting SD, Greiner JW. Combination of physical activity, nutrition, or other metabolic factors and vaccine response. FRONTIERS IN BIOSCIENCE : A JOURNAL AND VIRTUAL LIBRARY 2007; 12:4997-5029. [PMID: 17569626 PMCID: PMC2844938 DOI: 10.2741/2444] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A number of lifestyle factors that reduce cancer risk in the primary prevention setting may be potential new targets for use in combination with cancer vaccines. This review discusses the modulation of energy balance (physical activity, calorie restriction, and obesity prevention), and the supplementation with natural and synthetic analogs of vitamins A and E, as potential interventions for use in combination with cancer vaccines. Additionally, the pharmacologic manipulation of nutrient metabolism in the tumor microenvironment (e.g., arachidonic acid, arginine, tryptophan, and glucose metabolism) is discussed. This review includes a brief overview of the role of each agent in primary cancer prevention; outlines the effects of these agents on immune function, specifically adaptive and/or anti-tumor immune mechanisms, when known; and discusses the potential use of these interventions in combination with therapeutic cancer vaccines. Modulation of energy balance through exercise and strategies targeting nutrient metabolism in the tumor microenvironment represent the most promising interventions to partner with therapeutic cancer vaccines. Additionally, the use of vitamin E succinate and the retinoid X receptor-directed rexinoids in combination with cancer vaccines offer promise. In summary, a number of energy balance- and nutrition-related interventions are viable candidates for further study in combination with cancer vaccines.
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Affiliation(s)
- Kenneth W Hance
- Laboratory of Tumor Immunology and Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-1750, USA.
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Bradbury AR, Olopade OI. Genetic susceptibility to breast cancer. Rev Endocr Metab Disord 2007; 8:255-67. [PMID: 17508290 DOI: 10.1007/s11154-007-9038-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Accepted: 04/09/2007] [Indexed: 12/14/2022]
Abstract
Deleterious mutations in two breast and ovarian cancer susceptibility genes, BRCA1 and BRCA2 have been identified in breast and ovarian cancer families. Women with a BRCA1 or BRCA2 mutation are candidates for additional risk reduction measures such as intensive screening, prophylactic surgery or chemoprevention. Additional susceptibility genes have been identified, including PTEN, ATM, TP53, CHEK2, CASP8, PBRL and BRIP1. Yet, many women with a personal or family history suggestive of a hereditary susceptibility to breast cancer undergo genetic testing and no significant genetic alteration is found. Thus, there are other susceptibility genes that have not been identified, and it is likely that the remaining familial contribution to breast cancer will be explained by the presence of multiple low penetrance alleles that coexist to confer high penetrance risks (a polygenic model). The American Cancer Society has identified cancer prevention as a key component of cancer management and there is interest in developing individualized cancer prevention focused on identifying high risk individuals who are most likely to benefit from more aggressive risk reduction measures. Breast cancer risk assessment and genetic counseling are currently provided by genetic counselors, oncology nurse specialist, geneticists, medical and surgical oncologists, gynecologists and other health care professionals, often working within a multidisciplinary clinical setting. Current methods for risk assessment and predictive genetic testing have limitations and improvements in molecular testing and risk assessment tools is necessary to maximize individual breast cancer risk assessment and to fulfill the promise of cancer prevention.
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Affiliation(s)
- Angela R Bradbury
- Section of Hematology-Oncology, University of Chicago, Chicago, IL, USA.
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Liby KT, Yore MM, Sporn MB. Triterpenoids and rexinoids as multifunctional agents for the prevention and treatment of cancer. Nat Rev Cancer 2007; 7:357-69. [PMID: 17446857 DOI: 10.1038/nrc2129] [Citation(s) in RCA: 479] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Synthetic oleanane triterpenoids and rexinoids are two new classes of multifunctional drugs. They are neither conventional cytotoxic agents, nor are they monofunctional drugs that uniquely target single steps in signal transduction pathways. Synthetic oleanane triterpenoids have profound effects on inflammation and the redox state of cells and tissues, as well as being potent anti-proliferative and pro-apoptotic agents. Rexinoids are ligands for the nuclear receptor transcription factors known as retinoid X receptors. Both classes of agents can prevent and treat cancer in experimental animals. These drugs have unique molecular and cellular mechanisms of action and might prove to be synergistic with standard anti-cancer treatments.
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Affiliation(s)
- Karen T Liby
- Department of Pharmacology, Dartmouth Medical School, Hanover, NH 03755, USA
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Uray IP, Brown PH. Prevention of breast cancer: current state of the science and future opportunities. Expert Opin Investig Drugs 2007; 15:1583-600. [PMID: 17107283 DOI: 10.1517/13543784.15.12.1583] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Despite significant progress in breast cancer treatment, mammary tumours still represent the second most frequent cause of cancer-related death in women in the US, with > 211,000 new cases in 2005; however, an expanding range of options for early diagnosis and more reliable risk assessment offers new alternatives for disease control by cancer prevention. Completed large studies with the classical selective estrogen receptor modulator (SERM) tamoxifen have demonstrated that preventing breast cancer pharmacologically is now possible. Novel SERMs, aromatase inhibitors and gonadotropin-releasing hormone agonists targeting hormonal pathways are being tested in clinical trials, revealing the potential for dramatic reductions in tumour incidence with minimal side effects; however, SERMs and aromatase inhibitors are effective only against estrogen receptor-positive tumours, thus chemopreventive drugs targeting other critical signalling pathways (such as retinoids, selective COX inhibitors and tyrosine kinase inhibitors) may provide a means to prevent estrogen receptor-negative breast cancer. In the future, hormonal and estrogen receptor-independent agents may be combined to prevent the development of all mammary tumours. This article reviews the current and novel strategies for breast cancer prevention.
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Affiliation(s)
- Ivan P Uray
- Breast Care Center, Department of Medicine, Baylor College of Medicine, Methodist Hospital, Houston, TX 77030, USA
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Kim HT, Kong G, Denardo D, Li Y, Uray I, Pal S, Mohsin S, Hilsenbeck SG, Bissonnette R, Lamph WW, Johnson K, Brown PH. Identification of Biomarkers Modulated by the Rexinoid LGD1069 (Bexarotene) in Human Breast Cells Using Oligonucleotide Arrays. Cancer Res 2006; 66:12009-18. [PMID: 17178900 DOI: 10.1158/0008-5472.can-05-2515] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Retinoids have been found to be promising chemopreventive agents that play an important role in regulating cell growth, differentiation, and apoptosis. The action of retinoids is mediated by retinoid receptors (retinoic acid receptors and retinoid X receptors), which are nuclear transcription factors that, when bound to retinoids, regulate gene expression. LGD1069 is a highly selective RXR agonist that has reduced toxicity compared with retinoids. Our previous studies have shown that RXR-selective ligands (or "rexinoids"), including LGD1069, can inhibit the growth of normal and malignant breast cells and can suppress the development of breast cancer in transgenic mice. For the current study, we attempted to identify biomarkers of the chemopreventive effect of the RXR-selective retinoid LGD1069. In these experiments, we used Affymetrix microarrays to identify target genes that were modulated by LGD1069 in normal human breast cells. Affymetrix and dChip analysis identified more than 100 genes that were up-regulated or down-regulated by LGD1069 treatment. We then tested 16 of these genes in validation experiments using quantitative reverse transcription-PCR and Western blotting of independently prepared samples, and found that 15 of 16 genes were modulated in a similar manner in these validation experiments as in the microarray experiments. Genes found to be regulated include known retinoid-regulated genes, growth regulatory genes, transcription factors, and differentiation markers. We then showed that the expression of several of these rexinoid-regulated biomarkers is modulated in vivo in mammary glands from mice treated with LGD1069. These critical growth-regulating proteins will be promising targets of future agents for the prevention and treatment of breast cancer.
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Affiliation(s)
- Hee-Tae Kim
- Breast Center, Baylor College of Medicine, Houston, Texas 77030, USA
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Liby K, Rendi M, Suh N, Royce DB, Risingsong R, Williams CR, Lamph W, Labrie F, Krajewski S, Xu X, Kim H, Brown P, Sporn MB. The combination of the rexinoid, LG100268, and a selective estrogen receptor modulator, either arzoxifene or acolbifene, synergizes in the prevention and treatment of mammary tumors in an estrogen receptor-negative model of breast cancer. Clin Cancer Res 2006; 12:5902-9. [PMID: 17020999 DOI: 10.1158/1078-0432.ccr-06-1119] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE We tested whether a selective estrogen receptor modulator (SERM) and a rexinoid are active for prevention and treatment in the mouse mammary tumor virus-neu mouse model of estrogen receptor-negative breast cancer. EXPERIMENTAL DESIGN For prevention, mice were fed a powdered control diet, the SERM arzoxifene (Arz, 20 mg/kg diet), the rexinoid LG100268 (268, 30 mg/kg diet), or the combination for 60 weeks. In a second prevention study, mice were fed Arz (6 mg/kg diet), 268 (30 mg/kg diet), the combination of Arz and 268, the SERM acolbifene (Acol, 3 mg/kg diet), or the combination of Acol and 268 for 52 weeks. For the treatment studies, mice with tumors were fed combinations of a SERM and 268 for 4 weeks. RESULTS The rexinoid 268 and the SERMs Arz and Acol, as individual drugs, delayed the development of estrogen receptor-negative tumors. Moreover, the combination of a SERM and 268 was strikingly synergistic, as no tumors developed in any mouse fed the combination of 268 and a SERM. Moreover, this drug combination also induced significant tumor regression when used therapeutically. These drugs did not inhibit transgene expression in vitro or in vivo, and the combination of Arz and 268 inhibited proliferation and induced apoptosis in the tumors. CONCLUSION The combination of a rexinoid and SERM should be considered for future clinical trials.
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Affiliation(s)
- Karen Liby
- Dartmouth Medical School, Hanover, NH 03755, USA
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Ji Y, Lee HJ, Goodman C, Uskokovic M, Liby K, Sporn M, Suh N. The synthetic triterpenoid CDDO-imidazolide induces monocytic differentiation by activating the Smad and ERK signaling pathways in HL60 leukemia cells. Mol Cancer Ther 2006; 5:1452-8. [PMID: 16818503 DOI: 10.1158/1535-7163.mct-06-0136] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Synthetic triterpenoids, CDDO (2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid) or CDDO-imidazolide [2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid imidazolide (CDDO-Im)], induce cell differentiation in myeloid leukemia cells but their mechanism of action is not known. CDDO-Im induces monocytic differentiation markers, CD14, and nonspecific esterase in HL60 leukemia cells. We show that CDDO-Im activates the extracellular signal–regulated kinase (ERK) signaling pathway and up-regulates CCAAT/enhancer-binding protein β, a transcription factor critical for monocytic differentiation. The monocytic differentiation induced by CDDO-Im was partially blocked by the mitogen-activated protein kinase/ERK kinase 1 inhibitor PD98059, suggesting that the mitogen-activated protein kinase-ERK1/2 pathway plays a role in the differentiation induced by CDDO-Im. Furthermore, CDDO-Im activates the transforming growth factor β (TGF-β)/Smad signaling pathway. CDDO-Im enhanced the phosphorylation of the receptor-regulated Smads, phospho-Smad3, and phospho-Smad1/5, but not phospho-Smad2, and induced the expression of Smad4. Monocytic differentiation induced by CDDO-Im was blocked by both TGF-β antibody and the bone morphogenetic protein (BMP) antagonist Noggin. This indicates that activation of the Smad signaling pathway by triterpenoids is an important mechanism of monocytic differentiation. CDDO-Im induced the synthesis of mRNA for TGF-β2, BMP6, TGF-β type II receptor, and BMP type II receptor. CDDO-Im synergized with members of the TGF-β superfamily or with 1α,25(OH)2vitamin D3 (D3) in monocytic differentiation, and the synergistic effect was particularly striking in combination with D3. The combination of triterpenoids and D3 may have a practical use in differentiation therapy of myeloid leukemia as well as for promoting the formation of bone and cartilage. [Mol Cancer Ther 2006;5(6):1452–8]
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Affiliation(s)
- Yan Ji
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 164 Frelinghuysen Road, Piscataway, NJ 08854, USA
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38
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Yen WC, Lamph WW. A selective retinoid X receptor agonist bexarotene (LGD1069, Targretin) prevents and overcomes multidrug resistance in advanced prostate cancer. Prostate 2006; 66:305-16. [PMID: 16245282 DOI: 10.1002/pros.20347] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND We previously reported that a retinoid X receptor agonist bexarotene prevented and overcame acquired drug resistance in advanced breast cancer and non-small cell lung cancer. The present study was to evaluate the effect of bexarotene on the development of multidrug resistance in advanced prostate cancer. METHODS Human prostate cancer cells PC3 were repeatedly treated in culture with paclitaxel, doxorubicin, or cisplatin with or without bexarotene for 3 months. Thereafter, cells were isolated and characterized for their drug sensitivity. RESULTS Compared to parental cells, cells treated with a single therapeutic agent was resistant to the therapeutic agent, whereas cells treated with the combination remained chemosensitive. Cells with acquired drug resistance showed increased sensitivity to the cytotoxic agent when treated with the combination. Fluctuation analysis demonstrated that treatment with bexarotene decreased the rate of spontaneous development of drug resistance. These in vitro findings were further confirmed in the PC3 xenograft model. CONCLUSION Our results suggest a role of bexarotene in combination with chemotherapeutic agents in prevention and overcoming acquired drug resistance in advanced prostate cancer.
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Affiliation(s)
- Wan-Ching Yen
- Department of Molecular Oncology, Ligand Pharmaceuticals, Inc., San Diego, California 92121, USA.
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39
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Parikh RR, Gildener-Leapman N, Narendran A, Lin HY, Lemanski N, Bennett JA, Jacobson HI, Andersen TT. Prevention of N-methyl-N-nitrosourea-induced breast cancer by alpha-fetoprotein (AFP)-derived peptide, a peptide derived from the active site of AFP. Clin Cancer Res 2006; 11:8512-20. [PMID: 16322315 DOI: 10.1158/1078-0432.ccr-05-1651] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE alpha-Fetoprotein (AFP) is a protein of pregnancy associated with a decrease in lifetime risk of breast cancer in parous women. A synthetic, cyclic nonapeptide has been developed that mimics the antioncogenic active site of AFP. To test the hypothesis that the AFP-derived peptide (AFPep) can prevent breast cancer, the N-methyl-N-nitrosourea-induced breast cancer model was used in rats. EXPERIMENTAL DESIGN AFPep was given daily by injection beginning 10 days after N-methyl-N-nitrosourea treatment and continued for 23 days (a time designed to mimic pregnancy) or for other times to assess efficacy as a function of drug duration. Tumor incidence, multiplicity, and latency were noted as end points. At necropsy, pathology analysis of tumors and major organs were obtained. RESULTS AFPep prevented cancer in a dose-dependent fashion. Significantly longer mean tumor-free days (P < 0.02), lower tumor incidence (P = 0.004), and lower tumor multiplicity were observed for AFPep-treated groups. No evidence of host toxicity as measured by body weight, cage activity, fur texture, and organ weights (liver, uterus, heart, kidney, and spleen) were found in animals treated with AFPep. Mechanistic studies using transplantable human breast cancer xenografts showed that the peptide interfered with estrogen-dependent breast cancer growth inhibited the phosphorylation of the estrogen receptor and activated phosphorylation of p53. CONCLUSIONS AFPep is a well-tolerated, mechanistically novel, chemopreventive agent in models of breast cancer and warrants further development for the prevention and treatment of this disease in humans.
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Affiliation(s)
- Rahul R Parikh
- Center for Cardiovascular Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, Albany Medical College, Albany, New York 12208, USA
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Sporn MB, Liby KT. Cancer chemoprevention: scientific promise, clinical uncertainty. ACTA ACUST UNITED AC 2005; 2:518-25. [PMID: 16205771 DOI: 10.1038/ncponc0319] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Accepted: 08/18/2005] [Indexed: 12/23/2022]
Abstract
We review fundamental processes, such as mutation, oxidative stress, and inflammation that are critical for carcinogenesis and provide specific molecular targets for new chemopreventive agents. New information from molecular biology studies has identified such targets, including regulatory molecules such as Nrf2 (nuclear factor erythroid 2-related factor 2), epidermal growth factor receptor kinases, phosphatidylinositol 3-kinase, components of the Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway, nuclear factor-kappaB, and cyclin D. The development of new drugs for the control of these targets that are both safe and effective will be important for the future of cancer chemoprevention.
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Affiliation(s)
- Michael B Sporn
- Department of Pharmacology, Dartmouth Medical School, Hanover, NH 03755, USA.
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41
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Cesario RM, Stone J, Yen WC, Bissonnette RP, Lamph WW. Differentiation and growth inhibition mediated via the RXR:PPARgamma heterodimer in colon cancer. Cancer Lett 2005; 240:225-33. [PMID: 16271436 DOI: 10.1016/j.canlet.2005.09.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Accepted: 09/20/2005] [Indexed: 01/23/2023]
Abstract
This study evaluated the anti-tumor efficacy of combining the RXR agonist, bexarotene, with the PPARgamma agonist, rosiglitazone, in colon cancer. Moser, a human colon cancer cell line, was treated with bexarotene and rosiglitazone alone or in combination and the effect on growth and differentiation were examined. The data demonstrated that the bexarotene/rosiglitazone combination produced greater efficacy in growth inhibition than either single agent. Furthermore, combination treatment acted cooperatively to decrease COX-2 expression and PGE2 synthesis while increasing expression of the differentiation marker, CEA. These findings were confirmed in vivo in a Moser xenograft tumor model. Collectively, our data suggest a potential role for utilizing a combination regimen of a RXR and PPARgamma agonist in the treatment of colon cancer.
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Affiliation(s)
- Rosemary M Cesario
- Department of Molecular Oncology, Ligand Pharmaceuticals, San Diego, CA 92121, USA.
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Hermann TW, Yen WC, Tooker P, Fan B, Roegner K, Negro-Vilar A, Lamph WW, Bissonnette RP. The retinoid X receptor agonist bexarotene (Targretin) synergistically enhances the growth inhibitory activity of cytotoxic drugs in non-small cell lung cancer cells. Lung Cancer 2005; 50:9-18. [PMID: 15993980 DOI: 10.1016/j.lungcan.2005.05.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 05/09/2005] [Accepted: 05/17/2005] [Indexed: 10/25/2022]
Abstract
This study was designed to evaluate, using preclinical models of non-small cell lung cancer (NSCLC), the growth inhibitory effects of the retinoid X receptor (RXR) agonist bexarotene (LGD1069, Targretin) in combination with cytotoxic agents currently used as standard first-line therapy in advanced disease. Although single-agent bexarotene had modest growth inhibitory effects in several cell lines, efficacy was observed only in the micromolar range (>1muM), which approximates the plasma C(max) measured in pharmacokinetic studies in patients. However, when combined with paclitaxel or vinorelbine, bexarotene produced a concentration-dependent enhancement of the growth inhibitory activities of paclitaxel and vinorelbine. Formal synergy analysis using the Calu3 cell line demonstrated that the combination of bexarotene with either cytotoxic agent produced synergistic activity (combination index, CI<1). The in vitro observations were confirmed in vivo in a NSCLC xenograft tumor model (Calu3), where both bexarotene/paclitaxel and bexarotene/vinorelbine combinations produced significantly greater antitumor effects than the single agents. These results demonstrate that bexarotene can cooperate with widely used cytotoxic agents to decrease the growth of NSCLC tumor cells both in vitro and in vivo, and suggest the potential benefit of adding a RXR-selective agonist in combination with chemotherapy for NSCLC treatment. Furthermore, the data support the clinical observation from phase I/IIa trials suggesting that bexarotene has beneficial effects on survival when used in combination with cytotoxic agents in advanced NSCLC.
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Affiliation(s)
- Thomas W Hermann
- Department of Molecular Oncology, Ligand Pharmaceuticals Inc., 10275 Science Center Drive, San Diego, CA 92121, USA
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Shen Q, Brown PH. Transgenic mouse models for the prevention of breast cancer. Mutat Res 2005; 576:93-110. [PMID: 15888345 DOI: 10.1016/j.mrfmmm.2004.10.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 10/25/2004] [Accepted: 10/27/2004] [Indexed: 05/02/2023]
Abstract
Breast cancer prevention research has made remarkable progress in the past decade. Much of this progress has come from clinical trials. However, in the future to test the many promising agents that are now available, pre-clinical models of breast cancer are needed. Such models are now available. Useful models include rat and mouse models, particularly, the genetically engineered mice (GEM). Many transgenic mouse models have been generated by manipulating growth factors and their receptors, cell cycle regulators, signal transduction pathways, cellular differentiation, oncogenes and tumor suppressor genes. The transgenes are induced to express in the mouse mammary glands under the control of various transgenic promoters, which have respective characteristics in expression pattern and other biological attributes. These models are providing invaluable insight on the molecular mechanisms of breast tumorigenesis. In this review, we discuss the relative relevance of the most commonly used transgenic mouse models for breast cancer prevention studies, and provide examples of how these transgenic models can be used to conduct cancer prevention research. Due to the multi-factor, multi-step nature of breast cancer, many factors should be incorporated into a valid prevention study. However, many barriers to progress must be overcome, including access to and availability of new cancer preventive drugs, and difficulties in conducting studies of combinations of preventive agents.
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Affiliation(s)
- Qiang Shen
- Breast Center, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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Spillman MA, Schildkraut JM, Halabi S, Moorman P, Calingaert B, Bentley RC, Marks JR, Murphy S, Berchuck A. Transforming growth factor beta receptor I polyalanine repeat polymorphism does not increase ovarian cancer risk. Gynecol Oncol 2005; 97:543-9. [PMID: 15863158 DOI: 10.1016/j.ygyno.2005.01.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Revised: 12/19/2004] [Accepted: 01/07/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES It has been suggested that the 6A allele of the type I TGFbeta receptor (TGFbetaR1) polyalanine repeat tract polymorphism may increase susceptibility to various types of cancer including ovarian cancer. METHODS The TGFbetaR1 polyalanine polymorphism was genotyped in 588 ovarian cancer cases and 614 controls from a population-based case-control study in North Carolina. RESULTS Significant racial differences in the frequency of the 6A allele were observed between Caucasian (10.7%) and African-American (2.4%) controls (P < 0.001). One or two copies of the 6A allele of the TGFbetaR1 polyalanine polymorphism was carried by 18% of all controls and 19% of cases, and there was no association with ovarian cancer risk (OR = 1.07, 95% CI 0.80-1.44). The odds ratio for 6A homozygotes was 1.81 (95% CI 0.655.06), but these comprised only 0.98% of controls and 1.70% of cases. CONCLUSIONS The 6A allele of the TGFbetaR1 polyalanine polymorphism does not appear to increase ovarian cancer risk. Larger studies would be needed to exclude the possibility that the small fraction of individuals who are 6A homozygotes have an increased risk of ovarian or other cancers.
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Affiliation(s)
- Monique A Spillman
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Duke University, DUMC Box 3079, Durham, NC 27710, USA
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Medina D, Kittrell FS, Hill J, Shepard A, Thordarson G, Brown P. Tamoxifen inhibition of estrogen receptor-alpha-negative mouse mammary tumorigenesis. Cancer Res 2005; 65:3493-6. [PMID: 15833886 DOI: 10.1158/0008.5472.can-04-3869] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tamoxifen reduces the relative risk of breast cancer developing from specific premalignant lesions. Many breast cancers that arise after tamoxifen treatment are estrogen receptor-alpha (ER-alpha)-negative, although premalignant lesions such as atypical ductal hyperplasia are highly ER-alpha-positive. The p53 null mouse mammary epithelial transplant model is characterized by ER-alpha-positive premalignant lesions that give rise to both ER-alpha-positive and ER-alpha-negative tumors. Given this progression from ER-alpha-positive to ER-alpha-negative lesions, we tested the ability of tamoxifen to block or delay mammary tumorigenesis in several versions of this model. In groups 1 and 2, p53 null normal mammary epithelial transplants were maintained in virgin mice. In groups 3 to 5, the p53 null and mammary transplants were maintained in mice continuously exposed to high levels of progesterone. In groups 6 and 7, transplants of the premalignant outgrowth line PN8a were maintained in virgin mice. Tamoxifen blocked estrogen signaling in these mice as evidenced by decreases in progesterone-induced lateral branching and epithelial proliferation in the mammary epithelium. Tamoxifen did not alter the elevated levels of progesterone in the blood while significantly reducing the circulating level of prolactin. Tamoxifen reduced tumor incidence in p53 null normal mammary epithelial transplants maintained in virgin mice from 55% to 5% and in progesterone-stimulated mice from 81% to 21%. The majority of the resultant tumors were ER-alpha-negative. Tamoxifen also significantly delayed tumorigenesis in the ER-alpha-positive high premalignant line PN8a from 100% to 75%. These results show that tamoxifen delays the emergence of ER-alpha-negative tumors if given early in premalignant progression.
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Yen WC, Lamph WW. The selective retinoid X receptor agonist bexarotene (LGD1069, Targretin) prevents and overcomes multidrug resistance in advanced breast carcinoma. Mol Cancer Ther 2005; 4:824-34. [PMID: 15897247 DOI: 10.1158/1535-7163.mct-05-0018] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Acquired drug resistance represents a major challenge in the therapeutic management of breast cancer patients. We reported previously that the retinoid X receptor-selective agonist bexarotene (LGD1069, Targretin) was efficacious in treating animal models of tamoxifen-resistant breast cancer. The goal of this study was to evaluate the effect of bexarotene on development of acquired drug resistance and its role in overcoming acquired drug resistance in advanced breast cancer. Paclitaxel, doxorubicin, and cisplatin were chosen as model compounds to determine the effect of bexarotene on the development of acquired drug resistance. Human breast cancer cells MDA-MB-231 were repeatedly treated in culture with a given therapeutic agent with or without bexarotene for 3 months. Thereafter, cells were isolated and characterized for their drug sensitivity. Compared with parental cells, cells treated with a single therapeutic agent became resistant to the therapeutic agent, whereas cells treated with the bexarotene combination remained chemosensitive. Cells with acquired drug resistance, when treated with the combination, showed increased sensitivity to the cytotoxic agent. Furthermore, cells treated with the combination regimen had reduced invasiveness and angiogenic potential than their resistant counterparts. These in vitro findings were further confirmed in an in vivo MDA-MB-231 xenograft model. Our results suggest a role for bexarotene in combination with chemotherapeutic agents in prevention and overcoming acquired drug resistance in advanced breast carcinoma.
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Affiliation(s)
- Wan-Ching Yen
- Department of Molecular Oncology, Ligand Pharmaceuticals, Inc., 10275 Science Center Drive, San Diego, CA 92121, USA
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Fabian CJ, Kimler BF. Selective Estrogen-Receptor Modulators for Primary Prevention of Breast Cancer. J Clin Oncol 2005; 23:1644-55. [PMID: 15755972 DOI: 10.1200/jco.2005.11.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Carol J Fabian
- Department of Internal Medicine, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160, USA.
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Jones LP, Li M, Halama ED, Ma Y, Lubet R, Grubbs CJ, Deng CX, Rosen EM, Furth PA. Promotion of mammary cancer development by tamoxifen in a mouse model of Brca1-mutation-related breast cancer. Oncogene 2005; 24:3554-62. [PMID: 15750629 DOI: 10.1038/sj.onc.1208426] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Loss of full-length Brca1 in mammary epithelial cells of the mouse mammary tumor virus (MMTV)-Cre Brca1 conditional exon 11 deletion mouse model results in the development of mammary adenocarcinomas with similar genetic changes to those found in human BRCA1-mutation-related breast cancers. We used this experimental model to evaluate the chemopreventive effect of tamoxifen on the development of mammary preneoplasia and adenocarcinoma. No protective effects of tamoxifen administration on mammary cancer development were found. Instead, tamoxifen treatment significantly increased rates of mammary epithelial cell proliferation and the prevalence of mammary hyperplasia at 6 months of age. Tamoxifen-exposed mice developed adenocarcinomas at younger ages than control mice and a higher percentage of mice developed adenocarcinomas by 12 months of age. Both whole mouse and tissue culture cell models were used to test if loss of full-length Brca1 was associated with a relative increase in the agonist activity of tamoxifen. Tamoxifen induced increased ductal growth in MMTV-Cre Brca1 conditional mice compared to wild type. Estrogen receptor alpha (ERalpha) expression was downregulated in the tamoxifen-induced hyperplasias. Reducing BRCA1 levels in MCF-7 cells using siRNA resulted in a relative increase in the agonist activity of tamoxifen. Results suggest a model of mammary cancer progression in which loss of full-length Brca1 altered the agonist/antagonist activity of tamoxifen, resulting in tamoxifen-induced mammary epithelial cell proliferation with subsequent loss of ERalpha expression and development of ERalpha-negative hyperplasias and adenocarcinomas.
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Affiliation(s)
- Laundette P Jones
- Department of Oncology, Lombardi Cancer Center, Georgetown University, Washington, DC 20057, USA
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Abstract
With the current understanding of sporadic and familial breast cancer, it is now possible to identify individuals who have a moderate or high risk of breast cancer. For these individuals, it is useful to perform formal cancer risk assessment and develop an individualized risk reduction plan, including a tailored plan for cancer screening, preventive therapy, and/or prophylactic surgery. Assessment using a predictive model such as the Gail model is particularly useful in individuals at increased risk for sporadic breast cancer. In addition, assessment of risk based on histologic appearance of benign or premalignant breast lesions can be used to identify individuals for whom more aggressive risk reduction strategies are warranted. For individuals who are at risk for familial cancer syndromes, other predictive models are more appropriate. For this extremely high-risk group, genetic testing for mutations in familial cancer susceptibility genes is helpful to identify individuals who would benefit from even more aggressive cancer risk reduction strategies. Strategies to identify the levels of risk for breast cancer, including the identification of moderate, high, or very high risk groups are discussed. Management options for these groups are presented, including who to consider for more aggressive screening, chemoprevention, or prophylactic surgery. Current recommendations for screening, chemoprevention, and surgery for each risk group are presented. The ability to identify individuals at high risk for breast cancer now enables clinicians to intervene to reduce the risk of breast cancer. Aggressive screening, preventive therapy, and prophylactic surgery in moderate- to high-risk individuals should, in the future, significantly reduce the incidence of invasive breast cancer.
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Affiliation(s)
- Powel Brown
- Breast Center, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA.
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Yen WC, Corpuz MR, Prudente RY, Cooke TA, Bissonnette RP, Negro-Vilar A, Lamph WW. A Selective Retinoid X Receptor Agonist Bexarotene (Targretin) Prevents and Overcomes Acquired Paclitaxel (Taxol) Resistance in Human Non–Small Cell Lung Cancer. Clin Cancer Res 2004; 10:8656-64. [PMID: 15623650 DOI: 10.1158/1078-0432.ccr-04-0979] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Paclitaxel is an important anticancer agent for the treatment of non-small cell lung cancer (NSCLC). However, its use in cancer therapy is limited by development of acquired drug resistance. The goal of this study was to determine the effect of bexarotene on development of acquired paclitaxel resistance in NSCLC. EXPERIMENTAL DESIGN Human NSCLC Calu3 cells were repeatedly treated in culture with intermittent paclitaxel alone or in combination with continuous bexarotene for 3 months. Thereafter, cells were isolated and characterized for their drug sensitivity in vitro and in vivo. RESULTS Repeat exposure to paclitaxel alone resulted in development of paclitaxel resistance with cross-resistance to multidrug resistance P-glycoprotein substrates, whereas the bexarotene/paclitaxel combination prevented the development of drug resistance and the cells remained chemosensitive. Furthermore, paclitaxel resistance could be overcome when the resistant cells were treated with the combination regimen. Fluctuation analysis showed that treatment with bexarotene decreased the rate of spontaneous development of paclitaxel resistance. In vivo, the bexarotene/paclitaxel combination regimen produced a statistically significant decrease in tumor growth in a Calu3 NSCLC xenograft model compared with the single agents (two-tailed, P < 0.05). In addition, paclitaxel-resistant Calu3 tumors treated with the bexarotene/paclitaxel combination showed greater delay in tumor growth compared with those treated with paclitaxel alone. CONCLUSIONS Our results suggest that bexarotene may offer a novel approach to prevent and overcome paclitaxel resistance in patients with NSCLC.
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Affiliation(s)
- Wan-Ching Yen
- Department of Molecular Oncology, Ligand Pharmaceuticals, Inc., San Diego, California
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