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Alvarez-Fernandez C, Perez-Arnillas Q, Ruiz-Echeverria L, Rodriguez-Rubi D, Sanchez-Lorenzo L, Li-Torres W, Izquierdo-Manuel M, Berros JP, Luque-Cabal M, Jimenez-Fonseca P, Villanueva-Palicio N, Esteban-Gonzalez E. Reduced folate carrier (RFC) as a predictive marker for response to pemetrexed in advanced non-small cell lung cancer (NSCLC). Invest New Drugs 2013; 32:377-81. [DOI: 10.1007/s10637-013-9992-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 06/13/2013] [Indexed: 01/05/2023]
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152
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Effect of folic acid and vitamin B12 on pemetrexed antifolate chemotherapy in nutrient lung cancer cells. BIOMED RESEARCH INTERNATIONAL 2013; 2013:389046. [PMID: 23984356 PMCID: PMC3747471 DOI: 10.1155/2013/389046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/08/2013] [Indexed: 12/14/2022]
Abstract
Pemetrexed (MTA) is a multitargeted antifolate drug approved for lung cancer therapy. Clinically, supplementation with high doses of folic acid (FA) and vitamin B12 (VB12) lowers MTA cytotoxicities. An antagonistic effect of FA/VB12 on MTA efficacy has been proposed. However, patients who receive FA/VB12 show better tolerance to MTA with improved survival. The aims of this study are to investigate the modulation of FA and VB12 on MTA drug efficacy in human nonsmall cell lung cancer (NSCLC) cell lines. The sensitivities of cells, apoptosis, and MTA-regulated proteins were characterized to determine the possible effects of high doses of FA and VB12 on MTA efficacy. MTA has the lowest efficacy under 10% serum conditions. However, supplementation with FA and VB12 individually and additively reversed the insensitivity of NSCLC cells to MTA treatment with 10% serum. The enhanced sensitivities of cells following FA/VB12 treatment were correlated with increasing apoptosis and were specific to MTA but not to 5-fluorouracil (5-FU). Enhanced sensitivity was also associated with p21WAF1/Cip1 expression level. Our results revealed no antagonistic effect of high doses of FA/VB12 on MTA efficacy in cancer cells grown in nutrient medium. Furthermore, these data may partially explain why supplementation of FA and VB12 resulted in better survival in MTA-treated patients.
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153
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Weeks LD, Fu P, Gerson SL. Uracil-DNA glycosylase expression determines human lung cancer cell sensitivity to pemetrexed. Mol Cancer Ther 2013; 12:2248-60. [PMID: 23873851 DOI: 10.1158/1535-7163.mct-13-0172] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Uracil misincorporation into DNA is a consequence of pemetrexed inhibition of thymidylate synthase. The base excision repair (BER) enzyme uracil-DNA glycosylase (UNG) is the major glycosylase responsible for removal of misincorporated uracil. We previously illustrated hypersensitivity to pemetrexed in UNG(-/-) human colon cancer cells. Here, we examined the relationship between UNG expression and pemetrexed sensitivity in human lung cancer. We observed a spectrum of UNG expression in human lung cancer cells. Higher levels of UNG are associated with pemetrexed resistance and are present in cell lines derived from pemetrexed-resistant histologic subtypes (small cell and squamous cell carcinoma). Acute pemetrexed exposure induces UNG protein and mRNA, consistent with upregulation of uracil-DNA repair machinery. Chronic exposure of H1299 adenocarcinoma cells to increasing pemetrexed concentrations established drug-resistant sublines. Significant induction of UNG protein confirmed upregulation of BER as a feature of acquired pemetrexed resistance. Cotreatment with the BER inhibitor methoxyamine overrides pemetrexed resistance in chronically exposed cells, underscoring the use of BER-directed therapeutics to offset acquired drug resistance. Expression of UNG-directed siRNA and shRNA enhanced sensitivity in A549 and H1975 cells, and in drug-resistant sublines, confirming that UNG upregulation is protective. In human lung cancer, UNG deficiency is associated with pemetrexed-induced retention of uracil in DNA that destabilizes DNA replication forks resulting in DNA double-strand breaks and cell death. Thus, in experimental models, UNG is a critical mediator of pemetrexed sensitivity that warrants evaluation to determine clinical value.
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Affiliation(s)
- Lachelle D Weeks
- Corresponding Author: Stanton L. Gerson, Case Comprehensive Cancer Center, Wearn 151, 111000 Euclid Avenue, Cleveland, OH 44106.
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154
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Connelly S, DeMartino JK, Boger DL, Wilson IA. Biological and structural evaluation of 10R- and 10S-methylthio-DDACTHF reveals a new role for sulfur in inhibition of glycinamide ribonucleotide transformylase. Biochemistry 2013; 52:5133-44. [PMID: 23869564 DOI: 10.1021/bi4005182] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glycinamide ribonucleotide transformylase (GAR Tfase) is a folate-dependent enzyme in the de novo purine biosynthesis pathway, which has long been considered a potential target for development of anti-neoplastic therapeutics. Here we report the biological and X-ray crystallographic evaluations of both independent C10 diastereomers, 10S- and 10R-methylthio-DDACTHF, bound to human GAR Tfase, including the highest-resolution apo GAR Tfase structure to date (1.52 Å). Both diastereomers are potent inhibitors (Ki = 210 nM for 10R, and Ki = 180 nM for 10S) of GAR Tfase and exhibit effective inhibition of human leukemia cell growth (IC₅₀ = 80 and 50 nM, respectively). Their inhibitory activity was surprisingly high, and these lipophilic C10-substituted analogues show distinct advantages over their hydrophilic counterparts, most strikingly in retaining potency in mutant human leukemia cell lines that lack reduced folate carrier protein activity (IC₅₀ = 70 and 60 nM, respectively). Structural characterization reveals a new binding mode for these diastereoisomers, in which the lipophilic thiomethyl groups penetrate deeper into a hydrophobic pocket within the folate-binding site. In silico docking simulations of three other sulfur-containing folate analogues also indicate that this hydrophobic cleft represents a favorable region for binding lipophilic substituents. Overall, these results suggest sulfur and its substitutions play an important role in not only the binding of anti-folates to GAR Tfase but also the selectivity and cellular activity (growth inhibition), thereby presenting new possibilities for the future design of potent and selective anti-folate drugs that target GAR Tfase.
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Affiliation(s)
- Stephen Connelly
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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155
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Abstract
Mechanisms postulated to link folate and B12 metabolism with cancer, including genome-wide hypomethylation, gene-specific promoter hypermethylation, and DNA uracil misincorporation, have been observed in prostate tumor cells. However, epidemiological studies of prostate cancer risk, based on dietary intakes and blood levels of folate and vitamin B12 and on folate-pathway gene variants, have generated contradictory findings. In a meta-analysis, circulating concentrations of B12 (seven studies, OR = 1.10; 95% CI 1.01, 1.19; P = 0.002) and (in cohort studies) folate (five studies, OR = 1.18; 95% CI 1.00, 1.40; P = 0.02) were positively associated with an increased risk of prostate cancer. Homocysteine was not associated with risk of prostate cancer (four studies, OR = 0.91; 95% CI 0.69, 1.19; P = 0.5). In a meta-analysis of folate-pathway polymorphisms, MTR 2756A > G (eight studies, OR = 1.06; 95% CI 1.00, 1.12; P = 0.06) and SHMT1 1420C > T (two studies, OR = 1.11; 95% CI 1.00, 1.22; P = 0.05) were positively associated with prostate cancer risk. There were no effects due to any other polymorphisms, including MTHFR 677C > T (12 studies, OR = 1.04; 95% CI 0.97, 1.12; P = 0.3). The positive association of circulating B12 with an increased risk of prostate cancer could be explained by reverse causality. However, given current controversies over mandatory B12 fortification, further research to eliminate a causal role of B12 in prostate cancer initiation and/or progression is required. Meta-analysis does not entirely rule out a positive association of circulating folate with increased prostate cancer risk. As with B12, even a weak positive association would be a significant public health issue, given the high prevalence of prostate cancer and concerns about the potential harms versus benefits of mandatory folic acid fortification.
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156
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Martinez Molina D, Jafari R, Ignatushchenko M, Seki T, Larsson EA, Dan C, Sreekumar L, Cao Y, Nordlund P. Monitoring drug target engagement in cells and tissues using the cellular thermal shift assay. Science 2013; 341:84-7. [PMID: 23828940 DOI: 10.1126/science.1233606] [Citation(s) in RCA: 1312] [Impact Index Per Article: 119.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The efficacy of therapeutics is dependent on a drug binding to its cognate target. Optimization of target engagement by drugs in cells is often challenging, because drug binding cannot be monitored inside cells. We have developed a method for evaluating drug binding to target proteins in cells and tissue samples. This cellular thermal shift assay (CETSA) is based on the biophysical principle of ligand-induced thermal stabilization of target proteins. Using this assay, we validated drug binding for a set of important clinical targets and monitored processes of drug transport and activation, off-target effects and drug resistance in cancer cell lines, as well as drug distribution in tissues. CETSA is likely to become a valuable tool for the validation and optimization of drug target engagement.
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Affiliation(s)
- Daniel Martinez Molina
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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157
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Significance of folate receptor alpha and thymidylate synthase protein expression in patients with non-small-cell lung cancer treated with pemetrexed. J Thorac Oncol 2013; 8:19-30. [PMID: 23242435 DOI: 10.1097/jto.0b013e31827628ff] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Folate receptor alpha (FRA) regulates cellular uptake of folates and antifolates. Information about FRA protein expression in metastatic non-small-cell lung cancer (NSCLC) is limited. We investigated FRA as a biomarker for pemetrexed-based chemotherapy and compared it with thymidylate synthase (TS), the main target of pemetrexed. METHODS Pretreatment tumor specimens from 207 patients with advanced NSCLC were assessed for FRA and TS protein expression by immunohistochemistry using the H-score (range, 0-300) and correlated to patients' clinicopathological data, radiographic response, progression-free survival (PFS), and overall survival (OS). RESULTS Low total (cytoplasmic and nuclear) TS protein expression (H-score < 210) was associated with improved PFS (median: 5.6 versus 3.5 months; hazard ratio [HR] = 0.6379, p = 0.0131) and prolonged OS (median: 22.5 versus 11.5 months; HR = 0.5680,p = 0.0107). An association between lower TS levels and response to pemetrexed-based therapy was found-mean H-score 187 ± 5, median 180 for responders versus mean H-score 201 ± 4, median 210, for non-responders, p = 0.0244. High intracellular FRA expression (H-score ≥110) was associated with prolonged OS (28.9 versus 11.7 months, HR = 0.5316, p = 0.0040) and a trend for association with PFS (5.6 versus 4.1 months, HR = 0.7395, p = 0.0801) was noted. Membranous FRA expression was seen in 83% of patients, moreover, high membranous expression (H-score ≥20) was associated with improved PFS (5.6 versus 3.7 months, HR = 0.6445, p = 0.0306) and OS (22.1 versus 11.5 months, HR = 0.5378, p = 0.0131). CONCLUSIONS A large number of NSCLC patients have high expression of FRA and/or a low level of TS expression. Expression levels of FRA and TS were associated with clinical benefit from pemetrexed therapy.
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158
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Reduced Folate Carrier and Folylpolyglutamate Synthetase, but not Thymidylate Synthase Predict Survival in Pemetrexed-Treated Patients Suffering from Malignant Pleural Mesothelioma. J Thorac Oncol 2013; 8:644-53. [DOI: 10.1097/jto.0b013e318287c224] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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159
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Giovannetti E, Toffalorio F, De Pas T, Peters GJ. Pharmacogenetics of conventional chemotherapy in non-small-cell lung cancer: a changing landscape? Pharmacogenomics 2013; 13:1073-86. [PMID: 22838953 DOI: 10.2217/pgs.12.91] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Pharmacogenetics might be used to select patients who may benefit from specific chemotherapy that best matches the individual and tumor genetic profile, thus allowing maximum activity and minimal toxicity. Even if most studies in non-small-cell lung cancer yielded contradictory results, several potential biomarkers for sensitivity/resistance to platinum compounds, gemcitabine, taxanes and pemetrexed have been proposed. However, these markers need to be validated within larger prospective randomized trials of customized chemotherapy in homogeneous populations. Other critical points include the optimization/standardization of technical procedures, and further studies to unravel the extremely complex regulation of gene function. From this perspective, the evaluation of key factors influencing genotype-phenotype relationships, such as miRNAs, and functional studies to clarify pharmacokinetic/pharmacodynamic interactions, are fundamental for the pharmacogenetic optimization of cancer chemotherapy. Finally, limitation of the traditional pharmacogenetic approach relying only on candidate genes suspected of affecting drug response is now being overcome by the use of novel genome-wide studies.
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Affiliation(s)
- Elisa Giovannetti
- Department of Medical Oncology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
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160
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Ćalasan MB, Thurlings RM, Wulffraat NM, Prakken BJ. Translational medicine from bedside to bench and back again: methotrexate revisited. ACTA ACUST UNITED AC 2013. [DOI: 10.2217/ijr.13.13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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161
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Silva RMS, Fontes ACL, Silva KA, Sant'Ana TA, Ramos FJDC, Marques-Salles TDJ, Pombo-de-Oliveira MS, Muniz MTC. Polymorphisms Involved in Folate Metabolism Pathways and the Risk of the Development of Childhood Acute Leukemia. Genet Test Mol Biomarkers 2013; 17:147-52. [DOI: 10.1089/gtmb.2012.0174] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Rafaela Maria Seabra Silva
- Departamento de Genética, Universidade Federal de Pernambuco, Recife, Brazil
- Centro de Onco-Hematologia, Hospital Universitário Oswaldo Cruz, Recife, Brazil
| | - Alide Caroline Lima Fontes
- Centro de Onco-Hematologia, Hospital Universitário Oswaldo Cruz, Recife, Brazil
- Instituto de Ciências Biológicas, Universidade de Pernambuco, Recife, Brazil
| | - Karina Alves Silva
- Centro de Onco-Hematologia, Hospital Universitário Oswaldo Cruz, Recife, Brazil
| | - Thalita Araújo Sant'Ana
- Centro de Onco-Hematologia, Hospital Universitário Oswaldo Cruz, Recife, Brazil
- Instituto de Ciências Biológicas, Universidade de Pernambuco, Recife, Brazil
| | | | | | | | - Maria Tereza Cartaxo Muniz
- Departamento de Genética, Universidade Federal de Pernambuco, Recife, Brazil
- Centro de Onco-Hematologia, Hospital Universitário Oswaldo Cruz, Recife, Brazil
- Instituto de Ciências Biológicas, Universidade de Pernambuco, Recife, Brazil
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162
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Folylpoly-glutamate synthetase expression is associated with tumor response and outcome from pemetrexed-based chemotherapy in malignant pleural mesothelioma. J Thorac Oncol 2013; 7:1440-8. [PMID: 22895141 DOI: 10.1097/jto.0b013e318260deaa] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Pemetrexed-based chemotherapy represents the standard of care in first-line treatment of advanced malignant pleural mesothelioma (MPM). However, there are no established predictors of clinical benefit. Pemetrexed inhibits multiple enzymes involved in pyrimidine and purine synthesis, but the main target is thymidylate synthase (TS). After cellular uptake pemetrexed is converted into more effective polyglutamated forms by folylpoly-γ-glutamate synthetase (FPGS). We hypothesized that FPGS and TS protein expressions are associated with clinical outcome after pemetrexed-based chemotherapy. METHODS Pretreatment tumor samples from 84 patients with histologically confirmed MPM, who received pemetrexed combined with platinum (79 of 84) or single-agent pemetrexed (5 of 84) as first-line treatment, were retrospectively analyzed. FPGS and TS protein expressions were semiquantitatively assessed by using the Hybrid (H)-scoring system (range, 0-300). H-scores were correlated with radiological response according to modified Response Evaluation Criteria in Solid Tumors, progression-free survival (PFS) and overall survival (OS). RESULTS Median H-score of the entire cohort was 230 for FPGS (range, 100-300), and 210 for TS (range, 100-300). High FPGS protein expression was significantly associated with longer PFS (pCOX = 0.0337), better objective tumor response (partial response versus stable disease + progressive disease; pKW = 0.003), and improved disease-control rate (partial response + stable disease versus progressive disease; pKW = 0.0208), but not with OS. In addition, high TS protein expression was associated with progressive disease under pemetrexed-based therapy (p = 0.0383), and shorter OS (pCOX = 0.0071), but no association with PFS was observed. CONCLUSION FPGS and TS expressions were associated with clinical response and outcome to pemetrexed-based first-line chemotherapy in MPM. Prospective evaluation of FPGS and TS expressions and their prognostic/predictive power in MPM patients is warranted.
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163
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Navarrete O, Van Daele J, Stove C, Lambert W, Storozhenko S, Van Der Straeten D. Isolation and characterisation of an antifolate insensitive (afi1) mutant of Arabidopsis thaliana. PLANT BIOLOGY (STUTTGART, GERMANY) 2013; 15:37-44. [PMID: 22672761 DOI: 10.1111/j.1438-8677.2012.00602.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Antifolates can impair the synthesis and/or function of folates in living organisms. Mechanisms of resistance or tolerance to antifolates have been mainly described in plants using the drug methotrexate. In this work, the antifolate trimethoprim (TMP) was used with the aim of revealing a novel mechanism of resistance. EMS mutagenised seeds from Arabidopsis were screened to isolate individuals insensitive to TMP. Genetic analysis revealed a homozygous recessive mutation that segregates with the phenotype of tolerance to 50 μm TMP. Mapping analysis localised the mutation at the end of the short arm of chromosome 3. Preliminary characterisation demonstrated up-regulation of several genes from the folate biosynthetic pathway in the TMP insensitive mutant, and a slight increase in total folate content in the mutant as compared with the Col-0 control. Moreover, sequence analysis of the DHFR (dihydrofolate reductase) genes, which encode a known target for resistance to antifolates, did not reveal any changes. This study is the first report of a stable mutant insensitive (afi1) to the antifolate trimethoprim in plants, and suggests the existence of a novel mechanism of resistance to antifolates.
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Affiliation(s)
- O Navarrete
- Laboratory of Functional Plant Biology, Department of Physiology, Ghent University, Gent, Belgium
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164
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Lee HY, Ahn HK, Jeong JY, Kwon MJ, Han JH, Sun JM, Ahn JS, Park K, Choi YL, Ahn MJ. Favorable clinical outcomes of pemetrexed treatment in anaplastic lymphoma kinase positive non-small-cell lung cancer. Lung Cancer 2013; 79:40-5. [DOI: 10.1016/j.lungcan.2012.10.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 09/11/2012] [Accepted: 10/04/2012] [Indexed: 10/27/2022]
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165
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Obuchi W, Ohtsuki S, Uchida Y, Ohmine K, Yamori T, Terasaki T. Identification of transporters associated with Etoposide sensitivity of stomach cancer cell lines and methotrexate sensitivity of breast cancer cell lines by quantitative targeted absolute proteomics. Mol Pharmacol 2012. [PMID: 23197647 DOI: 10.1124/mol.112.081083] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Membrane transporter proteins may influence the sensitivity of cancer cells to anticancer drugs that can be recognized as substrates. The purpose of this study was to identify proteins that play a key role in the drug sensitivity of stomach and breast cancer cell lines by measuring the absolute protein expression levels of multiple transporters and other membrane proteins and examining their correlation to drug sensitivity. Absolute protein expression levels of 90 membrane proteins were examined by quantitative targeted absolute proteomics using liquid chromatography-linked tandem mass spectrometry. Among them, 11 and 14 membrane proteins, including transporters, were present in quantifiable amounts in membrane fraction of stomach cancer and breast cancer cell lines, respectively. In stomach cancer cell lines, the protein expression level of multidrug resistance-associated protein 1 (MRP1) was inversely correlated with etoposide sensitivity. MK571, an MRP inhibitor, increased both the cell-to-medium ratio of etoposide and the etoposide sensitivity of MRP1-expressing stomach cancer cell lines. In breast cancer cell lines, the protein expression level of reduced folate carrier 1 (RFC1) was directly correlated with methotrexate (MTX) sensitivity. Initial uptake rate and steady-state cell-to-medium ratio of [(3)H]MTX were correlated with both RFC1 expression level and MTX sensitivity. These results suggest that MRP1 modulates the etoposide sensitivity of stomach cancer cell lines and RFC1 modulates the MTX sensitivity of breast cancer cell lines. Our results indicate that absolute quantification of multiple membrane proteins could be a useful strategy for identification of candidate proteins involved in drug sensitivity.
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Affiliation(s)
- Wataru Obuchi
- Division of Membrane Transport and Drug Targeting, Department of Biochemical Pharmacology and Therapeutics, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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166
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Ayers D, Nasti A. Utilisation of nanoparticle technology in cancer chemoresistance. JOURNAL OF DRUG DELIVERY 2012; 2012:265691. [PMID: 23213536 PMCID: PMC3505656 DOI: 10.1155/2012/265691] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 10/11/2012] [Accepted: 10/11/2012] [Indexed: 01/08/2023]
Abstract
The implementation of cytotoxic chemotherapeutic drugs in the fight against cancer has played an invariably essential role for minimizing the extent of tumour progression and/or metastases in the patient and thus allowing for longer event free survival periods following chemotherapy. However, such therapeutics are nonspecific and bring with them dose-dependent cumulative adverse effects which can severely exacerbate patient suffering. In addition, the emergence of innate and/or acquired chemoresistance to the exposed cytotoxic agents undoubtedly serves to thwart effective clinical efficacy of chemotherapy in the cancer patient. The advent of nanotechnology has led to the development of a myriad of nanoparticle-based strategies with the specific goal to overcome such therapeutic hurdles in multiple cancer conditions. This paper aims to provide a brief overview and recollection of all the latest advances in the last few years concerning the application of nanoparticle technology to enhance the safe and effective delivery of chemotherapeutic agents to the tumour site, together with providing possible solutions to circumvent cancer chemoresistance in the clinical setting.
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Affiliation(s)
- Duncan Ayers
- Department of Pathology, Faculty of Medicine & Surgery, University of Malta, Msida MSD 2060, Malta
| | - Alessandro Nasti
- School of Medicine, Kanazawa University Hospital, University of Kanazawa, Kanazawa 920-1192, Japan
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167
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Abstract
This article focuses on the cellular, biochemical, and molecular pharmacology of antifolates and how a basic understanding of the mechanism of action of methotrexate, its cytotoxic determinants, mechanisms of resistance, and transport into and out of cells has led to the development of a new generation of antifolates, a process that continues in the laboratory and in the clinics. New approaches to folate-based cancer chemotherapy are described based on the targeted delivery of drugs to malignant cells.
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Affiliation(s)
- Michele Visentin
- Department of Medicine and the Albert Einstein Cancer Center, The Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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168
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Thymidylate synthase protein expression by IHC and gene copy number by SISH correlate and show great variability in non-small cell lung cancer. J Thorac Oncol 2012; 7:982-92. [PMID: 22551903 DOI: 10.1097/jto.0b013e31824fe95a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Increased expression of thymidylate synthase (TS) is thought to be associated with resistance to TS-targeting drugs, e.g., pemetrexed. METHODS TS protein expression (PE) and gene copy number (GCN) were assayed using immunohistochemistry and silver in situ hybridization, respectively, on primary tumors of 189 resected non-small cell lung patients. Associations with pathological and clinical features and prognosis were explored. RESULTS Median immunohistochemistry H-score was 220 (range, 10-380) on a 0 to 400 scale; 17% of the patients had a TS expression of 300 or more. TS PE expression did not significantly differ by histology and did not significantly associate with disease-free survival (DFS) or overall survival (OS). However, there was a tendency for increased DFS (p = 0.12) and OS (p = 0.12) in PE positive (>median) squamous-cell carcinoma (SCC) patients. Median GCN was 2.5 genes/nucleus (range, 1.4-9.6); 29% of patients had GCN of 3 or more, 7% of 4 or more and 0.8% amplification. GCN differed by histology (p = 0.015); 50% of SCCs having GCN more than 2.5 versus 32% of adenocarcinomas. There was no significant relationship between TS GCN and DFS or OS; however, a trend toward better DFS (p = 0.18) and OS (p = 0.10) with increased GCN in SCCs was observed. TS GCN was significantly correlated with PE (r = 0.30, p = 0.0009). CONCLUSIONS TS PE and GCN vary widely in non-small cell lung and correlate significantly with each other. TS GCN is higher in SCCs, whereas TS PE does not associate with histological subtypes, clinical features, or survival. Variability of TS PE and GCN may indicate potential benefit from pemetrexed therapy in selected SCC patients.
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169
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Roussel B, Johnson-Farley N, Kerrigan JE, Scotto KW, Banerjee D, Felczak K, Pankiewicz KW, Gounder M, Lin H, Abali EE, Bertino JR. A second target of benzamide riboside: dihydrofolate reductase. Cancer Biol Ther 2012; 13:1290-8. [PMID: 22954684 DOI: 10.4161/cbt.21786] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Dihydrofolate reductase (DHFR) is an essential enzyme involved in de novo purine and thymidine biosynthesis. For several decades, selective inhibition of DHFR has proven to be a potent therapeutic approach in the treatment of various cancers including acute lymphoblastic leukemia, non-Hodgkin's lymphoma, osteogenic sarcoma, carcinoma of the breast, and head and neck cancer. Therapeutic success with DHFR inhibitor methotrexate (MTX) has been compromised in the clinic, which limits the success of MTX treatment by both acquired and intrinsic resistance mechanisms. We report that benzamide riboside (BR), via anabolism to benzamide adenine dinucleotide (BAD) known to potently inhibit inosine monophosphate dehydrogenase (IMPDH), also inhibits cell growth through a mechanism involving downregulation of DHFR protein. Evidence to support this second site of action of BR includes the finding that CCRF-CEM/R human T-cell lymphoblasic leukemia cells, resistant to MTX as a consequence of gene amplification and overexpression of DHFR, are more resistant to BR than are parental cells. Studies of the mechanism by which BR lowers DHFR showed that BR, through its metabolite BAD, reduced NADP and NADPH cellular levels by inhibiting nicotinamide adenine dinucleotide kinase (NADK). As consequence of the lack of NADPH, DHFR was shown to be destabilized. We suggest that, inhibition of NADK is a new approach to downregulate DHFR and to inhibit cell growth.
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Affiliation(s)
- Breton Roussel
- Department of Medicine, Biochemistry and Pharmacology, Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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170
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Rodd AL, Ververis K, Karagiannis TC. Safety and efficacy of pralatrexate in the management of relapsed or refractory peripheral T-cell lymphoma. CLINICAL MEDICINE INSIGHTS-ONCOLOGY 2012; 6:305-14. [PMID: 23032692 PMCID: PMC3459669 DOI: 10.4137/cmo.s8536] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Peripheral T-cell lymphoma (PTCL) represents a relatively rare group of heterogeneous non-Hodgkin lymphomas, with generally poor prognosis. Historically, there has been a lack of consensus regarding appropriate therapeutic measures for the disease, with conventional frontline chemotherapies being utilized in most cases. Following promising results obtained in 2009, the methotrexate analogue, pralatrexate, became the first drug to gain US FDA approval for the treatment of refractory PTCL. This antimetabolite was designed to have a higher affinity for reduced folate carrier (RFC) and folylpolyglutamate synthetase (FPGS). RFC is the principal transporter for cell entrance of folates and antifolates. Once inside the cell, pralatrexate is efficiently polyglutamated by FPGS. Pralatrexate has demonstrated varying degrees of efficacy in peripheral T-cell lymphoma, with response rates differing between the multiple subtypes of the disease. While phase III studies are still to be completed, early clinical trials indicate that pralatrexate is promising new therapeutic for PTCL.
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Affiliation(s)
- Annabelle L Rodd
- Epigenomic Medicine, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, Victoria, Australia. ; Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
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171
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Gonen N, Assaraf YG. Antifolates in cancer therapy: Structure, activity and mechanisms of drug resistance. Drug Resist Updat 2012; 15:183-210. [DOI: 10.1016/j.drup.2012.07.002] [Citation(s) in RCA: 269] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Revised: 06/25/2012] [Accepted: 07/11/2012] [Indexed: 01/19/2023]
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172
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Desmoulin SK, Wang L, Polin L, White K, Kushner J, Stout M, Hou Z, Cherian C, Gangjee A, Matherly LH. Functional loss of the reduced folate carrier enhances the antitumor activities of novel antifolates with selective uptake by the proton-coupled folate transporter. Mol Pharmacol 2012; 82:591-600. [PMID: 22740639 DOI: 10.1124/mol.112.079004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Uptake of 6-substituted pyrrolo[2,3-d]pyrimidine thienoyl antifolates with four or three bridge carbons [compound 1 (C1) and compound 2 (C2), respectively] into solid tumors by the proton-coupled folate transporter (PCFT) represents a novel therapeutic strategy that harnesses the acidic tumor microenvironment. Although these compounds are not substrates for the reduced folate carrier (RFC), the major facilitative folate transporter, RFC expression may alter drug efficacies by affecting cellular tetrahydrofolate (THF) cofactor pools that can compete for polyglutamylation and/or binding to intracellular enzyme targets. Human tumor cells including wild-type (WT) and R5 (RFC-null) HeLa cells express high levels of PCFT protein. C1 and C2 inhibited proliferation of R5 cells 3 to 4 times more potently than WT cells or R5 cells transfected with RFC. Transport of C1 and C2 was virtually identical between WT and R5 cells, establishing that differences in drug sensitivities between sublines were independent of PCFT transport. Steady-state intracellular [³H]THF cofactors derived from [³H]5-formyl-THF were depleted in R5 cells compared with those in WT cells, an effect exacerbated by C1 and C2. Whereas C1 and C2 polyglutamates accumulated to similar levels in WT and R5 cells, there were differences in polyglutamyl distributions in favor of the longest chain length forms. In severe combined immunodeficient mice, the antitumor efficacies of C1 and C2 were greater toward subcutaneous R5 tumors than toward WT tumors, confirming the collateral drug sensitivities observed in vitro. Thus, solid tumor-targeted antifolates with PCFT-selective cellular uptake should have enhanced activities toward tumors lacking RFC function, reflecting contraction of THF cofactor pools.
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Affiliation(s)
- Sita Kugel Desmoulin
- Graduate Program in Cancer Biology and Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan, USA
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173
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Goler-Baron V, Sladkevich I, Assaraf YG. Inhibition of the PI3K-Akt signaling pathway disrupts ABCG2-rich extracellular vesicles and overcomes multidrug resistance in breast cancer cells. Biochem Pharmacol 2012; 83:1340-8. [DOI: 10.1016/j.bcp.2012.01.033] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2011] [Revised: 01/29/2012] [Accepted: 01/31/2012] [Indexed: 11/16/2022]
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174
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Goler-Baron V, Assaraf YG. Overcoming multidrug resistance via photodestruction of ABCG2-rich extracellular vesicles sequestering photosensitive chemotherapeutics. PLoS One 2012; 7:e35487. [PMID: 22530032 PMCID: PMC3329466 DOI: 10.1371/journal.pone.0035487] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 03/16/2012] [Indexed: 12/25/2022] Open
Abstract
Multidrug resistance (MDR) remains a dominant impediment to curative cancer chemotherapy. Efflux transporters of the ATP-binding cassette (ABC) superfamily including ABCG2, ABCB1 and ABCC1 mediate MDR to multiple structurally and functionally distinct antitumor agents. Recently we identified a novel mechanism of MDR in which ABCG2-rich extracellular vesicles (EVs) form in between attached neighbor breast cancer cells and highly concentrate various chemotherapeutics in an ABCG2-dependent manner, thereby sequestering them away from their intracellular targets. Hence, development of novel strategies to overcome MDR modalities is a major goal of cancer research. Towards this end, we here developed a novel approach to selectively target and kill MDR cancer cells. We show that illumination of EVs that accumulated photosensitive cytotoxic drugs including imidazoacridinones (IAs) and topotecan resulted in intravesicular formation of reactive oxygen species (ROS) and severe damage to the EVs membrane that is shared by EVs-forming cells, thereby leading to tumor cell lysis and the overcoming of MDR. Furthermore, consistent with the weak base nature of IAs, MDR cells that are devoid of EVs but contained an increased number of lysosomes, highly accumulated IAs in lysosomes and upon photosensitization were efficiently killed via ROS-dependent lysosomal rupture. Combining targeted lysis of IAs-loaded EVs and lysosomes elicited a synergistic cytotoxic effect resulting in MDR reversal. In contrast, topotecan, a bona fide transport substrate of ABCG2, accumulated exclusively in EVs of MDR cells but was neither detected in lysosomes of normal breast epithelial cells nor in non-MDR breast cancer cells. This exclusive accumulation in EVs enhanced the selectivity of the cytotoxic effect exerted by photodynamic therapy to MDR cells without harming normal cells. Moreover, lysosomal alkalinization with bafilomycin A1 abrogated lysosomal accumulation of IAs, consequently preventing lysosomal photodestruction of normal breast epithelial cells. Thus, MDR modalities including ABCG2-dependent drug sequestration within EVs can be rationally converted to a pharmacologically lethal Trojan horse to selectively eradicate MDR cancer cells.
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Affiliation(s)
- Vicky Goler-Baron
- The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Yehuda G. Assaraf
- The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
- * E-mail:
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175
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Imidazoacridinone-dependent lysosomal photodestruction: a pharmacological Trojan horse approach to eradicate multidrug-resistant cancers. Cell Death Dis 2012; 3:e293. [PMID: 22476101 PMCID: PMC3358008 DOI: 10.1038/cddis.2012.30] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Multidrug resistance (MDR) remains a primary hindrance to curative cancer therapy. Thus, introduction of novel strategies to overcome MDR is of paramount therapeutic significance. Sequestration of chemotherapeutics in lysosomes is an established mechanism of drug resistance. Here, we show that MDR cells display a marked increase in lysosome number. We further demonstrate that imidazoacridinones (IAs), which are cytotoxic fluorochromes, undergo a dramatic compartmentalization in lysosomes because of their hydrophobic weak base nature. We hence developed a novel photoactivation-based pharmacological Trojan horse approach to target and eradicate MDR cancer cells based on photo-rupture of IA-loaded lysosomes and tumor cell lysis via formation of reactive oxygen species. Illumination of IA-loaded cells resulted in lysosomal photodestruction and restoration of parental cell drug sensitivity. Lysosomal photodestruction of MDR cells overexpressing the key MDR efflux transporters ABCG2, ABCB1 or ABCC1 resulted in 10- to 52-fold lower IC50 values of various IAs, thereby restoring parental cell sensitivity. Finally, in vivo application of this photodynamic therapy strategy after i.v. injection of IAs in human ovarian tumor xenografts in the chorioallantoic membrane model revealed selective destruction of tumors and their associated vasculature. These findings identify lysosomal sequestration of IAs as an Achilles heel of MDR cells that can be harnessed to eradicate MDR tumor cells via lysosomal photodestruction.
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176
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Sáez-Ayala M, Fernández-Pérez MP, Montenegro MF, Sánchez-del-Campo L, Chazarra S, Piñero-Madrona A, Cabezas-Herrera J, Rodríguez-López JN. Melanoma coordinates general and cell-specific mechanisms to promote methotrexate resistance. Exp Cell Res 2012; 318:1146-59. [PMID: 22484375 DOI: 10.1016/j.yexcr.2012.03.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/27/2012] [Accepted: 03/22/2012] [Indexed: 12/28/2022]
Abstract
Melanoma, the most aggressive form of skin cancer, is notoriously resistant to all current modalities of cancer therapy, including to the drug methotrexate. Melanosomal sequestration and cellular exportation of methotrexate have been proposed to be important melanoma-specific mechanisms that contribute to the resistance of melanoma to methotrexate. In addition, other mechanisms of resistance that are present in most epithelial cancer cells are also operative in melanoma. This report elucidates how melanoma orchestrates these mechanisms to become extremely resistant to methotrexate, where both E2F1 and checkpoint kinase 1 (Chk1), two molecules with dual roles in survival/apoptosis, play prominent roles. The results indicated that MTX induced the depletion of dihydrofolate in melanoma cells, which stimulated the transcriptional activity of E2F1. The elevate expression of dihydrofolate reductase and thymidylate synthase, two E2F1-target genes involved in folate metabolism and required for G(1) progression, favored dTTP accumulation, which promoted DNA single strand breaks and the subsequent activation of Chk1. Under these conditions, melanoma cells are protected from apoptosis by arresting their cell cycle in S phase. Excess of dTTP could also inhibit E2F1-mediated apoptosis in melanoma cells.
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Affiliation(s)
- Magalí Sáez-Ayala
- Department of Biochemistry and Molecular Biology A, School of Biology, University of Murcia, Murcia, Spain
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177
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Gómez-Gómez Y, Organista-Nava J, Saavedra-Herrera MV, Rivera-Ramírez AB, Terán-Porcayo MA, Del Carmen Alarcón-Romero L, Illades-Aguiar B, Leyva-Vázquez MA. Survival and risk of relapse of acute lymphoblastic leukemia in a Mexican population is affected by dihydrofolate reductase gene polymorphisms. Exp Ther Med 2012; 3:665-672. [PMID: 22969948 DOI: 10.3892/etm.2012.447] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 12/06/2011] [Indexed: 11/06/2022] Open
Abstract
Dihydrofolate reductase (DHFR) is the major target of methotrexate, a key component in childhood acute lymphoblastic leukemia (ALL) treatment. Polymorphisms in the gene coding for DHFR have been associated with adverse event treatment. This study evaluated the effect of the -A317G and C829T polymorphisms in the DHFR gene on survival and risk of relapse of ALL. Seventy patients with ALL and 100 healthy individuals were genotyped by the polymerase chain reaction-restriction fragment length polymorphism method. An association between the polymorphisms and the risk of relapse was found (p<0.05); patients with the -317G/G genotype were found to have an 8.55 (95% CI 1.84-39.70) higher chance of relapse and carriers of the 829T/T genotype had a 14.0 (95% CI 1.13-172.63) higher chance of relapse. Other variables, such as age and leukocyte count, were associated (p<0.05) with the risk of relapse of the disease. Individuals with the G/G and T/T genotype of the -A317G and C829T polymorphisms had poorer survival compared to other genotype groups (log-rank test; p<0.05). Although preliminary, these data seem to suggest a role for the DHFR polymorphisms in the risk of relapse of ALL and the mortality risk in these patients.
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178
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179
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Smit EF, Socinski MA, Mullaney BP, Myrand SP, Scagliotti GV, Lorigan P, Reck M, Ciuleanu T, von Pawel J, Karaseva NA, Szczesna A, Ohannesian D, Powell E, Hozak RR, Hong S, Guba SC, Thatcher N. Biomarker analysis in a phase III study of pemetrexed-carboplatin versus etoposide-carboplatin in chemonaive patients with extensive-stage small-cell lung cancer. Ann Oncol 2011; 23:1723-9. [PMID: 22186609 DOI: 10.1093/annonc/mdr563] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Clinical results of a randomized phase III trial comparing pemetrexed-carboplatin (PC) with etoposide-carboplatin (EC) in chemonaive patients with extensive-stage disease small-cell lung cancer (ED-SCLC) resulted in trial closure for futility; biomarker analyses using immunohistochemistry (IHC) and single-nucleotide polymorphisms (SNPs) are described herein. PATIENTS AND METHODS Thymidylate synthase (TS), excision repair cross complementing-1 (ERCC1), glycinamide ribonucleotide formyltransferase (GARFT), and folylpolyglutamate synthetase (FPGS) were investigated using IHC (n=395). SNPs were genotyped for TS, FPGS, γ-glutamyl hydrolase (GGH), methylenetetrahydrofolate reductase (MTHFR), folate receptor-α FR-α, and solute carrier 19A1 (SLC19A1; n=611). RESULTS None of the IHC biomarkers (folate pathway or ERCC1) were found to be predictive or prognostic in this setting. rs2838952 (adjacent to SLC19A1) had significant treatment-independent association with overall survival (OS; hazard ratio 0.590, P=0.01). Nine GGH-associated SNPs interacted with rs3788205 (SLC19A1) for OS on the PC arm. rs12379987 (FPGS) interacted with treatment for OS (interaction P=0.036). CONCLUSION Potential ERCC1 and folate pathway IHC biomarkers failed to predict outcome in either study arm in ED-SCLC. SNPs in regions including FPGS and SLC19A1 and interacting SNPs in GGH and SLC19A1 were associated with differences in OS; however, none of these SNPs predicted for greater survival with PC over EC.
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Affiliation(s)
- E F Smit
- Department of Pulmonary Diseases, Vrije University Medical Center, Amsterdam, The Netherlands.
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180
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Casanova M, Medina-Pérez A, Moreno-Beltran M, Mata-Vazquez M, Rueda A. Critical appraisal of pralatrexate in the management of difficult-to-treat peripheral T cell lymphoma. Ther Clin Risk Manag 2011; 7:401-8. [PMID: 22076116 PMCID: PMC3208406 DOI: 10.2147/tcrm.s22834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Aggressive T cell lymphomas are a subgroup of lymphomas with a particularly poor prognosis. This is especially true for patients with recurrent or refractory disease, who typically have limited response to salvage therapy and extremely poor overall survival. For this reason, there is a strong need to develop potentially active drugs for these malignancies. Pralatrexate is a novel antifolate designed to have high affinity for reduced folate carrier type 1. Preclinical and clinical studies have demonstrated that pralatrexate has significant activity against T cell lymphomas. The dose-limiting toxicity for pralatrexate is mucositis, which can be abrogated with folic acid and vitamin B12 supplementation. Pralatrexate is the first single agent approved for the treatment of patients with relapsed or refractory peripheral T cell lymphoma. This approval was based on an overall objective response rate observed in the pivotal study. The overall response rate was 29%, with a median duration of 10.1 months. This article reviews the biochemistry, preclinical experience, metabolism, and pharmacokinetics of pralatrexate, including the clinical experience with this agent in lymphoma. Future areas of development are now focused on identifying synergistic combinations of pralatrexate with other agents and the evaluation of predictive markers for clinical benefit.
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Affiliation(s)
- M Casanova
- Oncohematology Service, Hospital Costa del Sol, Marbella, Spain
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181
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Visentin M, Chang MH, Romero MF, Zhao R, Goldman ID. Substrate- and pH-specific antifolate transport mediated by organic anion-transporting polypeptide 2B1 (OATP2B1-SLCO2B1). Mol Pharmacol 2011; 81:134-42. [PMID: 22021325 DOI: 10.1124/mol.111.074823] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human organic anion-transporting polypeptide (OATP) 2B1 (OATP-B; SLCO2B1) is expressed in the apical membrane of the small intestine and the hepatocyte basolateral membrane and transports structurally diverse organic anions with a wide spectrum of pH sensitivities. This article describes highly pH-dependent OATP2B1-mediated antifolate transport and compares this property with that of sulfobromophthalein (BSP), a preferred OATP2B1 substrate. At pH 5.5 and low substrate concentrations (~2.5 μM), only [(3)H]pemetrexed influx [in contrast to methotrexate (MTX), folic acid, and reduced folates] could be detected in OATP2B1-transfected HeLa R1-11 cells that lack endogenous folate-specific transporters. Influx was optimal at pH 4.5 to 5.5, falling precipitously with an increase in pH >6.0; BSP influx was independent of pH. Influx of both substrates at low pH was markedly inhibited by the proton ionophore 4-(trifluoromethoxy)phenylhydrazone; BSP influx was also suppressed at pH 7.4. At 300 μM MTX, influx was one-third that of pemetrexed; influx of folic acid, (6S)5-methyltetrahydrofolate, or (6S)5-formyltetrahydrofolate was not detected. There were similar findings in OATP2B1-expressing Xenopus laevis oocytes. The pemetrexed influx K(m) was ~300 μM; the raltitrexed influx K(i) was ~70 μM at pH 5.5. Stable expression of OAPT2B1 in HeLa R1-11 cells resulted in substantial raltitrexed, but modest pemetrexed, growth inhibition consistent with their affinities for this carrier. Hence, OATP2B1 represents a low-affinity transport route for antifolates (relative affinities: raltitrexed > pemetrexed > MTX) at low pH. In contrast, the high affinity of this transporter for BSP relative to antifolates seems to be intrinsic to its binding site and independent of the proton concentration.
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Affiliation(s)
- Michele Visentin
- Experimental and Clinical Pharmacology Unit, Centro di Riferimento Oncologico, National Cancer Institute, Aviano, Italy
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182
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Anaplastic lymphoma kinase gene rearrangements in non-small cell lung cancer are associated with prolonged progression-free survival on pemetrexed. J Thorac Oncol 2011; 6:774-80. [PMID: 21336183 DOI: 10.1097/jto.0b013e31820cf053] [Citation(s) in RCA: 191] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
HYPOTHESIS To explore whether the progression-free survival (PFS) with pemetrexed differs between anaplastic lymphoma kinase (ALK)-positive and other major molecular subtypes of non-small cell lung cancer. METHODS In an ALK-enriched population, patients with metastatic non-small cell lung cancer were screened by ALK fluorescence in situ hybridization and for epidermal growth factor receptor (EGFR) and KRAS mutations. Triple-tested, pemetrexed-treated patients (monotherapy or combination therapy) were identified and PFS with pemetrexed captured retrospectively. RESULTS Eighty-nine eligible cases were identified (19 ALK fluorescence in situ hybridization positive, 12 EGFR mutant, 21 KRAS mutant, and 37 triple negatives). Eighty-three cases (93%) were adenocarcinomas, two were adenosquamous, one squamous, and three had large cell histology. None of the ALK-positive patients had received crizotinib before pemetrexed. Pemetrexed was first-line therapy in 48% (72% as platinum-based combinations). Median PFS (95% confidence interval) data were EGFR mutant (5.5 months; 1-9), KRAS mutant (7 months; 1.5-10), ALK positive (9 months; 3-12), and triple negative (4 months; 3-5). In a multivariate analysis adjusting for line of therapy, mono- versus platinum and nonplatinum combination therapy, age, sex, histology, and smoking status, the only variable associated with prolonged PFS on pemetrexed was ALK+ (hazard ratio = 0.36 [95% confidence interval: 0.17-0.73], p = 0.0051). CONCLUSIONS In this exploratory analysis, ALK-positive patients have a significantly longer PFS on pemetrexed compared with triple-negative patients, whereas EGFR or KRAS mutant patients do not. This information should be considered when sizing randomized studies in ALK-positive patients that involve pemetrexed. Pemetrexed should also be prioritized as a cytotoxic to explore further in patients with known ALK-positive disease.
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Abstract
Recent advances in non-small-cell lung cancer (NSCLC) therapy mean the relatively simple discrimination between small-cell and 'non-small-cell' carcinoma is insufficient to determine the best treatment for individual patients. Safety, efficacy and prescribing requirements mandate more specific subtyping of NSCLC for several new drugs: practice made difficult by the tumour heterogeneity combined with the paucity of tissue in most diagnostic samples. Immunohistochemical approaches have emerged as accurate predictors of probable tumour histotype. P63 and/or cytokeratins 5 and 6 and thyroid transcription factor 1 (TTF1) are among the best predictors, respectively, of squamous and adenocarcinoma histology. Molecular characteristics may predict response to both newer molecular targeted agents and traditional cytotoxic agents. Specific mutations in the epidermal growth factor receptor (EGFR) gene as predictors of response to EGFR tyrosine kinase inhibitors (erlotinib, gefitinib) is the first example of markers which predict response to targeted agents. Actual drug targets [e.g. thymidilate synthase (TS) - pemetrexed] or markers of the tumour's ability to repair cytotoxic drug-induced damage [e.g. excision repair cross-complementation group 1 (ERCC1) - cisplatin] may well also complement NSCLC diagnosis. This extended diagnostic requirement from increasingly limited material provided by minimally invasive biopsy techniques poses major challenges for pathology.
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Affiliation(s)
- Keith M Kerr
- Aberdeen University Medical School, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, UK.
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184
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Galvani E, Peters GJ, Giovannetti E. Thymidylate synthase inhibitors for non-small cell lung cancer. Expert Opin Investig Drugs 2011; 20:1343-56. [PMID: 21905922 DOI: 10.1517/13543784.2011.617742] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION The folate-dependent enzyme thymidylate synthase (TS) plays a pivotal role in DNA replication/repair and cancer cell proliferation, and represents a valid target for the treatment of several tumor types, including NSCLC. NSCLC is the leading cause of cancer-related mortality, and several TS inhibitors have gone into preclinical and clinical testing, with pemetrexed emerging for its approval and widespread use as first-/second-line and maintenance therapy for this disease. AREAS COVERED This review summarizes the therapeutic options in NSCLC, as well as the background and rationale for targeting TS. The authors also review recent pharmacogenetic studies and data from clinical trials evaluating novel TS inhibitors, hoping that the reader will gain a comprehensive overview of the field of TS inhibition, specifically relating to drugs used or being developed for lung cancer patients. EXPERT OPINION TS is a validated target in NSCLC. However, benefits from conventional chemotherapy in NSCLC have plateaued, and more cost-effective results should be obtained with individualized treatment. Accordingly, the clinical success for TS inhibitors may depend on our ability to correctly administer these agents following biomarker-driven patient selection, including TS genotype and expression, and using the right combination therapy.
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Affiliation(s)
- Elena Galvani
- VU University Medical Center, Department of Medical Oncology, Amsterdam, The Netherlands
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185
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Calvaresi M, Zerbetto F. In Silico Carborane Docking to Proteins and Potential Drug Targets. J Chem Inf Model 2011; 51:1882-96. [DOI: 10.1021/ci200216z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Matteo Calvaresi
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
| | - Francesco Zerbetto
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
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186
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Caffo O, Fratino L, Barbieri R, Perin A, Martini T, Sava T, Segati R, Vaccher E, Bernardo Bassan F, Veccia A, Pappagallo G, Galligioni E. Pemetrexed as second-line chemotherapy for castration-resistant prostate cancer after docetaxel failure: results from a phase II study. Urol Oncol 2011; 31:180-6. [PMID: 21803618 DOI: 10.1016/j.urolonc.2010.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 11/21/2010] [Accepted: 11/22/2010] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Although there is no standard treatment after docetaxel failure in patients with castration-resistant prostate cancer (CRPC), second-line chemotherapy is increasingly required. Its mechanism of action and toxicity profile make pemetrexed suitable for testing in this setting. METHODS AND MATERIALS Patients with docetaxel-resistant CRPC received pemetrexed 500 mg/m(2) every 3 weeks for 6 courses. The usual premedication with vitamin supplementation and dexamethasone prophylaxis was regularly administered. The primary objective was to quantify the biochemical response rate. RESULTS The biochemical response rate was 10.5% (95% CI 1.3-33.1), with 2 patients showing a reduction in prostate specific antigen (PSA) of ≥50%. The null hypothesis that the PSA response rate would be less than 20% was therefore accepted, and patient accrual was stopped after the evaluation of the 19th patient. The 1-year overall survival rate was 61.5%, with a median survival of 14 months. A considerable proportion of the patients (36%) were withdrawn from the study because of hematologic and nonhematologic toxicity. CONCLUSIONS Our experience with pemetrexed in CRPC patients appears discouraging in terms of activity and toxicity. No further studies of this drug should be performed in CRPC patients.
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Affiliation(s)
- Orazio Caffo
- Medical Oncology Department, Santa Chiara Hospital, Trento, Italy.
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187
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Wu CP, Hsieh CH, Wu YS. The Emergence of Drug Transporter-Mediated Multidrug Resistance to Cancer Chemotherapy. Mol Pharm 2011; 8:1996-2011. [DOI: 10.1021/mp200261n] [Citation(s) in RCA: 167] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Chung-Pu Wu
- Department of Physiology and Pharmacology, Chang Gung University, Tao-Yuan 333, Taiwan
- Molecular Medicine Research Center, Chang Gung University, Tao-Yuan 333, Taiwan
| | - Chia-Hung Hsieh
- Graduate Institute of Basic Medical Science, China Medical University and Hospital, Taichung, Taiwan
| | - Yu-Shan Wu
- Department of Chemistry, Tunghai University, Taichung, Taiwan
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188
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Askari BS, Krajinovic M. Dihydrofolate reductase gene variations in susceptibility to disease and treatment outcomes. Curr Genomics 2011; 11:578-83. [PMID: 21629435 PMCID: PMC3078682 DOI: 10.2174/138920210793360925] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 07/25/2010] [Accepted: 09/07/2010] [Indexed: 01/07/2023] Open
Abstract
Dihydrofolate reductase (DHFR) catalyzes the reduction of dihydrofolate to tetrahydrofolate (THF). THF is needed for the action of folate-dependent enzymes and is thus essential for DNA synthesis and methylation. The importance of this reaction is demonstrated by the effectiveness of antifolate medications used to treat cancer by inhibiting DHFR, thereby depleting THF and slowing DNA synthesis and cell proliferation. Due to the pivotal role that DHFR plays in folate metabolism and cancer treatment, changes in the level of DHFR expression can affect susceptibility to a variety of diseases dependent on folate status such as spina bifida and cancer. Likewise, variability in DHFR expression can affect sensitivity to anti-cancer drugs such as the folate antagonist methotrexate. Alterations in DHFR expression can be due to polymorphisms in the DHFR gene. Several variations have recently been described in DHFR, including promoter polymorphisms, the 19-bp deletion allele and variations in 3’UTR. These polymorphisms seem to be functional, affecting mRNA levels through various interesting mechanisms, including regulation through RNA interference. Several groups have assessed the association of these polymorphisms with folate levels, risk of cancer and spina bifida as well as the outcome of diseases treated with MTX. The latter may lead to different treatment schedules, improving treatment efficacy and/or allowing for a reduction in drug side effects. This review will summarize present knowledge regarding the predictive potential of DHFR polymorphisms in disease and treatment.
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189
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Abdel-Haleem AM, El-Zeiry MI, Mahran LG, Abou-Aisha K, Rady MH, Rohde J, Mostageer M, Spahn-Langguth H. Expression of RFC/SLC19A1 is associated with tumor type in bladder cancer patients. PLoS One 2011; 6:e21820. [PMID: 21760912 PMCID: PMC3132752 DOI: 10.1371/journal.pone.0021820] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 06/12/2011] [Indexed: 11/22/2022] Open
Abstract
Urinary bladder cancer (UBC) ranks ninth in worldwide cancer. In Egypt, the pattern of bladder cancer is unique in that both the transitional and squamous cell types prevail. Despite much research on the topic, it is still difficult to predict tumor progression, optimal therapy and clinical outcome. The reduced folate carrier (RFC/SLC19A1) is the major transport system for folates in mammalian cells and tissues. RFC is also the primary means of cellular uptake for antifolate cancer chemotherapeutic drugs, however, membrane transport of antifolates by RFC is considered as limiting to antitumor activity. The purpose of this study was to compare the mRNA expression level of RFC/SLC19A1 in urothelial and non-urothelial variants of bladder carcinomas. Quantification of RFC mRNA in the mucosa of 41 untreated bladder cancer patients was performed using RT-qPCR. RFC mRNA steady-state levels were ∼9-fold higher (N = 39; P<0.0001) in bladder tumor specimens relative to normal bladder mRNA. RFC upregulation was strongly correlated with tumor type (urothelial vs. non-urothelial; p<0.05) where median RFC mRNA expression was significantly (p<0.05) higher in the urothelial (∼14-fold) compared to the non-urothelial (∼4-fold) variant. This may account for the variation in response to antifolate-containing regimens used in the treatment of either type. RFC mRNA levels were not associated with tumor grade (I, II and III) or stage (muscle-invasive vs. non-muscle invasive) implying that RFC cannot be used for prognostic purposes in bladder carcinomas and its increased expression is an early event in human bladder tumors pathogenesis. Further, RFC can be considered as a potential marker for predicting response to antifolate chemotherapy in urothelial carcinomas.
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Affiliation(s)
- Alyaa M. Abdel-Haleem
- Department of Pharmacology and Toxicology, German University in Cairo, Cairo, Egypt
- * E-mail: (AMA-H); (HS-L)
| | - Maha I. El-Zeiry
- Department of Pharmacology and Toxicology, German University in Cairo, Cairo, Egypt
| | - Laila G. Mahran
- Department of Pharmacology and Toxicology, German University in Cairo, Cairo, Egypt
| | - Khaled Abou-Aisha
- Department of Pharmacology and Toxicology, German University in Cairo, Cairo, Egypt
| | - Mona H. Rady
- Department of Pharmacology and Toxicology, German University in Cairo, Cairo, Egypt
| | - Jan Rohde
- Department of Pharmacology and Toxicology, German University in Cairo, Cairo, Egypt
| | - Marwa Mostageer
- Department of Pharmacology and Toxicology, German University in Cairo, Cairo, Egypt
| | - Hilde Spahn-Langguth
- Department of Pharmacology and Toxicology, German University in Cairo, Cairo, Egypt
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Graz, Austria
- * E-mail: (AMA-H); (HS-L)
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190
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Zhang D, Ochi N, Takigawa N, Tanimoto Y, Chen Y, Ichihara E, Hotta K, Tabata M, Tanimoto M, Kiura K. Establishment of pemetrexed-resistant non-small cell lung cancer cell lines. Cancer Lett 2011; 309:228-35. [PMID: 21742432 DOI: 10.1016/j.canlet.2011.06.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 05/27/2011] [Accepted: 06/12/2011] [Indexed: 10/18/2022]
Abstract
Pemetrexed (PEM), a multitargeted antifolate with manageable toxicity, is active against non-squamous non-small cell lung cancer; however, most patients eventually acquire resistance to PEM. To elucidate the resistant mechanism, we established PEM-resistant lung adenocarcinoma cell lines. Two parental cell lines, PC-9 and A549, were treated with step-wise increasing concentrations of PEM. Growth inhibition was determined by the 3-[4,5-dimethyl-thizol-2-yl]-2,5-diphenyltetrazolium bromide assay. Expression of the genes encoding thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT) was analyzed by quantitative real-time reverse transcriptase polymerase chain reaction. The four PC-9 sublines were more resistant than the PC-9 cell line to PEM (2.2-, 2.9-, 8.4-, and 14.3-fold, respectively). The four A549 sublines also showed more resistance to PEM (7.8-, 9.6-, 42.3-, and 42.4-fold, respectively) than the parent cell line. All resistant sublines showed cross-resistance to cisplatin, but not to docetaxel, vinorelbine, 5-fluorouracil, or the active metabolite of irinotecan, SN-38. All PEM-resistant sublines expressed more TS than the parental cells, by polymerase chain reaction and Western blotting. DHFR was significantly increased in the four PEM-resistant A549 sublines. GARFT did not correlate with resistance to PEM. In summary, PEM-resistant cells remained sensitive to docetaxel, vinorelbine, 5-fluorouracil, and irinotecan. TS expression appeared to be associated with resistance to PEM.
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Affiliation(s)
- Dan Zhang
- Department of Hematology, Oncology, and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
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191
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Rouquette I, Mazieres J. Un regard simple sur la biologie moléculaire du cancer bronchique : la thymidylate synthase (TS). Rev Mal Respir 2011; 28:773-7. [DOI: 10.1016/j.rmr.2010.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/29/2010] [Indexed: 10/18/2022]
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192
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Ansari M, Sauty G, Labuda M, Gagné V, Rousseau J, Moghrabi A, Laverdière C, Sinnett D, Krajinovic M. Polymorphism in multidrug resistance-associated protein gene 3 is associated with outcomes in childhood acute lymphoblastic leukemia. THE PHARMACOGENOMICS JOURNAL 2011; 12:386-94. [DOI: 10.1038/tpj.2011.17] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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193
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Lu Y, Stinnette TW, Westrick E, Klein PJ, Gehrke MA, Cross VA, Vlahov IR, Low PS, Leamon CP. Treatment of experimental adjuvant arthritis with a novel folate receptor-targeted folic acid-aminopterin conjugate. Arthritis Res Ther 2011; 13:R56. [PMID: 21463515 PMCID: PMC3132048 DOI: 10.1186/ar3304] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 02/23/2011] [Accepted: 04/04/2011] [Indexed: 12/11/2022] Open
Abstract
Introduction Folate receptor (FR)-expressing macrophages have been shown to accumulate at sites of inflammation, where they promote development of inflammatory symptoms. To target such a macrophage population, we designed and evaluated the biologic activity of EC0746, a novel folic acid conjugate of the highly potent antifolate, aminopterin. Methods Using a FR-positive subclone of murine macrophage-derived RAW264.7 cells and rat thioglycollate-elicited macrophages, we studied the effect of EC0746 on dihydrofolate reductase activity, cell proliferation, and cellular response towards bacterial lipopolysaccharide as well as IFNγ activation. The EC0746 anti-inflammatory activity, pharmacokinetics, and toxicity were also evaluated in normal rats or in rats with adjuvant-induced arthritis; that is, a FR-positive macrophage model that closely resembles rheumatoid arthritis in humans. Results EC0746 suppresses the proliferation of RAW264.7 cells and prevents the ability of nonproliferating rat macrophages to respond to inflammatory stimuli. In the macrophage-rich rat arthritis model, brief treatment with subcutaneously administered EC0746 is shown to mediate an FR-specific anti-inflammatory response that is more potent than either orally administered methotrexate or subcutaneously delivered etanercept. More importantly, EC0746 therapy is also shown to be ~40-fold less toxic than unmodified aminopterin, with fewer bone marrow and gastrointestinal problems. Conclusions EC0746 is the first high FR-binding dihydrofolate reductase inhibitor that demonstrates FR-specific anti-inflammatory activities both in vitro and in vivo. Our data reveal that a relatively toxic anti-inflammatory drug, such as aminopterin, can be targeted with folic acid to inflammatory macrophages and thereby relieve inflammatory symptoms with greatly reduced toxicity.
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Affiliation(s)
- Yingjuan Lu
- Endocyte, Inc., 3000 Kent Avenue, West Lafayette, IN 47906, USA
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194
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Shapira A, Livney YD, Broxterman HJ, Assaraf YG. Nanomedicine for targeted cancer therapy: towards the overcoming of drug resistance. Drug Resist Updat 2011; 14:150-63. [PMID: 21330184 DOI: 10.1016/j.drup.2011.01.003] [Citation(s) in RCA: 319] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 01/12/2011] [Accepted: 01/14/2011] [Indexed: 12/11/2022]
Abstract
Anticancer drug resistance almost invariably emerges and poses major obstacles towards curative therapy of various human malignancies. In the current review we will distinguish between mechanisms of chemoresistance that are predominantly mediated by ATP-driven multidrug resistance (MDR) efflux transporters, typically of the ATP-binding cassette (ABC) superfamily, and those that are independent of such drug efflux pumps. In recent years, multiple nanoparticle (NP)-based therapeutic systems have been developed that were rationally designed to overcome drug resistance by neutralizing, evading or exploiting various drug efflux pumps and other resistance mechanisms. NPs are being exploited for selective drug delivery to tumor cells, to cancer stem/tumor initiating cells and/or to the supportive cancer cell microenvironment, i.e. stroma or tumor vasculature. Some of these NPs are currently undergoing preclinical in vivo studies as well as advanced stages of clinical evaluation with promising results. Nanovehicles harboring a payload of therapeutic drug combinations for the selective targeting and elimination of tumor cells as well as the simultaneous overcoming of mechanisms of drug resistance are a subject of intense research efforts, some of which are expected to enter clinical trials in the near future. In the present review we highlight novel approaches to selectively target cancer cells and overcome drug resistance phenomena, through the use of various nanometric drug delivery systems. In the near future, it is anticipated that innovative theragnostic nanovehicles will be developed which will harbor four major components: (1) a selective targeting moiety, (2) a diagnostic imaging aid for the localization of the malignant tumor and its micro- or macrometastases, (3) a cytotoxic, small molecule drug(s) or novel therapeutic biological(s), and (4) a chemosensitizing agent aimed at neutralizing a resistance mechanism, or exploiting a molecular "Achilles hill" of drug resistant cells. We propose to name these envisioned four element-containing nanovehicle platform, "quadrugnostic" nanomedicine. This targeted strategy holds promise in paving the way for the introduction of highly effective nanoscopic vehicles for cancer therapeutics while overcoming drug resistance.
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Affiliation(s)
- Alina Shapira
- Russell Berrie Nanotechnology Institute, Technion, Haifa, Israel
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195
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Goler-Baron V, Assaraf YG. Structure and function of ABCG2-rich extracellular vesicles mediating multidrug resistance. PLoS One 2011; 6:e16007. [PMID: 21283667 PMCID: PMC3025911 DOI: 10.1371/journal.pone.0016007] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2010] [Accepted: 12/02/2010] [Indexed: 02/04/2023] Open
Abstract
Multidrug resistance (MDR) is a major impediment to curative cancer chemotherapy. The ATP-Binding Cassette transporters ABCG2, ABCB1 and ABCC2 form a unique defense network against multiple structurally and functionally distinct chemotherapeutics, thereby resulting in MDR. Thus, deciphering novel mechanisms of MDR and their overcoming is a major goal of cancer research. Recently we have shown that overexpression of ABCG2 in the membrane of novel extracellular vesicles (EVs) in breast cancer cells results in mitoxantrone resistance due to its dramatic sequestration in EVs. However, nothing is known about EVs structure, biogenesis and their ability to concentrate multiple antitumor agents. To this end, we here found that EVs are structural and functional homologues of bile canaliculi, are apically localized, sealed structures reinforced by an actin-based cytoskeleton and secluded from the extracellular milieu by the tight junction proteins occludin and ZO-1. Apart from ABCG2, ABCB1 and ABCC2 were also selectively targeted to the membrane of EVs. Moreover, Ezrin-Radixin-Moesin protein complex selectively localized to the border of the EVs membrane, suggesting a key role for the tethering of MDR pumps to the actin cytoskeleton. The ability of EVs to concentrate and sequester different antitumor drugs was also explored. Taking advantage of the endogenous fluorescence of anticancer drugs, we found that EVs-forming breast cancer cells display high level resistance to topotecan, imidazoacridinones and methotrexate via efficient intravesicular drug concentration hence sequestering them away from their cellular targets. Thus, we identified a new modality of anticancer drug compartmentalization and resistance in which multiple chemotherapeutics are actively pumped from the cytoplasm and highly concentrated within the lumen of EVs via a network of MDR transporters differentially targeted to the EVs membrane. We propose a composite model for the structure and function of MDR pump-rich EVs in cancer cells and their ability to confer multiple anticancer drug resistance.
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Affiliation(s)
- Vicky Goler-Baron
- The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Yehuda G. Assaraf
- The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
- * E-mail:
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196
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Abstract
Background: Pralatrexate is a dihydrofolate reductase (DHFR) inhibitor with high affinity for reduced folate carrier 1 (RFC-1) and folylpolyglutamate synthetase (FPGS), resulting in extensive internalization and accumulation in tumour cells. Pralatrexate is approved in the US for the treatment of relapsed or refractory peripheral T-cell lymphoma and is being investigated in various malignancies. Here, we evaluated molecular correlates of sensitivity to pralatrexate and explored combinations with a variety of anticancer agents. Methods: Antiproliferative effects of pralatrexate were evaluated in 15 human-cancer cell lines using the MTT assay. Gene expression was evaluated using qRT–PCR. Results: Pralatrexate and methotrexate had a similar pattern of cytotoxicity, pralatrexate being more potent. Pralatrexate potentiated the effects of platinum drugs, antimetabolites and EGFR inhibitors. Dose- and time-dependent cytotoxicity of pralatrexate correlated with high mRNA expression of FPGS. Acquired resistance to pralatrexate was associated with decreased RFC-1 expression, whereas methotrexate resistance correlated with increased DHFR expression, suggesting different mechanisms of acquired resistance. Conclusion: Pralatrexate was more potent than methotrexate in a panel of solid tumour lines. Our findings support the further clinical development of pralatrexate in combination with certain cytotoxics and targeted therapies, and suggest that RFC-1, FPGS and DHFR may be potential biomarkers of outcome.
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197
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CoFactor: Folate Requirement for Optimization of 5-Fluouracil Activity in Anticancer Chemotherapy. JOURNAL OF ONCOLOGY 2010; 2010:934359. [PMID: 21209714 PMCID: PMC3010680 DOI: 10.1155/2010/934359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Revised: 11/02/2010] [Accepted: 11/08/2010] [Indexed: 11/17/2022]
Abstract
Intracellular reduced folate exists as a "pool" of more than 6 interconvertable forms. One of these forms, 5,10 methylenetetrahydrofolic acid (CH(2)THF), is the key one-carbon donor and reduced folate substrate for thymidylate synthase (TS). This pathway has been an important target for chemotherapy as it provides one of the necessary nucleotide substrates for DNA synthesis. The fluoropyrimidine 5-fluorouracil (5-FU) exerts its main cytotoxic activity through TS inhibition. Leucovorin (5-formyltetrahydrofolate; LV) has been used to increase the intracellular reduced folate pools and enhance TS inhibition. However, it must be metabolized within the cell through multiple intracellular enzymatic steps to form CH2THF. CoFactor (USAN fotrexorin calcium, (dl)-5,10,-methylenepteroyl-monoglutamate calcium salt) is a reduced folate that potentiates 5-FU cytotoxicity. According to early clinical trials, when 5-FU is modulated by CoFactor instead of LV, there is greater anti-tumor activity and less toxicity. This review presents the emerging role of CoFactor in colorectal and nongastrointestinal malignancies.
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198
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Glauner H, Ruttekolk IR, Hansen K, Steemers B, Chung YD, Becker F, Hannus S, Brock R. Simultaneous detection of intracellular target and off-target binding of small molecule cancer drugs at nanomolar concentrations. Br J Pharmacol 2010; 160:958-70. [PMID: 20590591 DOI: 10.1111/j.1476-5381.2010.00732.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND AND PURPOSE In vitro assays that determine activities of drug candidates with isolated targets have only limited predictive value for activities in cellular assays. Poor membrane permeability and off-target binding are major reasons for such discrepancies. However, it still difficult to directly analyse off-target binding at the same time as target binding, on a subcellular level. Here, we present a combination of fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS) as a solution to this problem. EXPERIMENTAL APPROACH The well-established dihydrofolate reductase inhibitor methotrexate and the kinase inhibitors PD173956 and purvalanol B were conjugated via polyethylene glycol linkers with the fluorophore Cy5. The cellular uptake and subcellular distribution of these compounds in single human cancer-derived cells were investigated by confocal laser scanning microscopy. In addition, molecular interactions inside the cell with the respective target proteins and off-target binding were detected simultaneously in the nanomolar range by FCCS and FCS, respectively, using cells expressing green fluorescent protein fusion proteins of dihydrofolate reductase and Abelson kinase 1. KEY RESULTS Large differences in the interaction patterns were found for these compounds. For methotrexate-Cy5, drug-target interactions could be detected and dissociation constants determined. In contrast, PD173956-Cy5 showed strong interactions with intracellular high-molecular weight structures, other than its target. CONCLUSIONS AND IMPLICATIONS The combination of FCS and FCCS provides a powerful means to assess subcellular pharmacokinetics and dynamics of drug candidates at nanomolar concentrations.
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Affiliation(s)
- Heike Glauner
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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199
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Gonen N, Assaraf YG. The obligatory intestinal folate transporter PCFT (SLC46A1) is regulated by nuclear respiratory factor 1. J Biol Chem 2010; 285:33602-13. [PMID: 20724482 DOI: 10.1074/jbc.m110.135640] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Folates are essential vitamins that play a key role as one-carbon donors in a spectrum of biosynthetic pathways including RNA and DNA synthesis. The proton-coupled folate transporter (PCFT/SLC46A1) mediates obligatory intestinal folate absorption. Loss-of-function mutations in PCFT result in hereditary folate malabsorption, an autosomal recessive disorder characterized by very low folate levels in the blood and cerebrospinal fluid. Hereditary folate malabsorption manifests within the first months after birth with anemia, immune deficiency, and neurological deficits. Here we studied the role of inducible trans-activators of PCFT gene expression. Bioinformatics identified three putative nuclear respiratory factor 1 (NRF-1) binding sites in the minimal promoter. The following evidence establish that PCFT is an NRF-1-responsive gene; electrophoretic mobility shift assay showed NRF-1 binding to native but not mutant NRF-1 sites, whereas antibody-mediated supershift analysis and chromatin immunoprecipitation revealed NRF-1 binding to its consensus sites within the PCFT promoter. Moreover, mutational inactivation of individual or all NRF-1 binding sites resulted in 40-60% decrease in luciferase reporter activity. Consistently, overexpression of NRF-1 or a constitutively active NRF-1 VP-16 construct resulted in increased reporter activity and PCFT mRNA levels. Conversely, introduction of a dominant-negative NRF-1 construct markedly repressed reporter activity and PCFT mRNA levels; likewise, introduction of NRF-1 siRNA duplexes to cells resulted in decreased PCFT transcript levels. Moreover, NRF-1 silencing down-regulated genes encoding for key folate transporters and enzymes in folate metabolism. These novel findings identify NRF-1 as a major inducible transcriptional regulator of PCFT gene expression. The implications of this linkage between folate transport and metabolism with mitochondria biogenesis and respiration are discussed.
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Affiliation(s)
- Nitzan Gonen
- Fred Wyszkowski Cancer Research Laboratory, Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
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200
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Napieralski R, Brünner N, Mengele K, Schmitt M. Emerging biomarkers in breast cancer care. Biomark Med 2010; 4:505-22. [DOI: 10.2217/bmm.10.73] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Currently, decision-making for breast cancer treatment in the clinical setting is mainly based on clinical data, histomorphological features of the tumor tissue and a few cancer biomarkers such as steroid hormone receptor status (estrogen and progesterone receptors) and oncoprotein HER2 status. Although various therapeutic options were introduced into the clinic in recent decades, with the objective of improving surgery, radiotherapy, biochemotherapy and chemotherapy, varying response of individual patients to certain types of therapy and therapy resistance is still a challenge in breast cancer care. Therefore, since breast cancer treatment should be based on individual features of the patient and her tumor, tailored therapy should be an option by integrating cancer biomarkers to define patients at risk and to reliably predict their course of the disease and/or response to cancer therapy. Recently, candidate-marker approaches and genome-wide transcriptomic and epigenetic screening of different breast cancer tissues and bodily fluids resulted in new promising biomarker panels, allowing breast cancer prognosis, prediction of therapy response and monitoring of therapy efficacy. These biomarkers are now subject of validation in prospective clinical trials.
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Affiliation(s)
- Rudolf Napieralski
- Clinical Research Unit, Department of Obstetrics & Gynecology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Germany
| | - Nils Brünner
- University of Copenhagen, Faculty of Life Sciences, Department of Veterinary Disease Biology, Ridebanevej 9, DK-1870 Frederiksberg C, Denmark
| | - Karin Mengele
- Clinical Research Unit, Department of Obstetrics & Gynecology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Germany
| | - Manfred Schmitt
- Clinical Research Unit, Department of Obstetrics & Gynecology, Ismaninger Strasse 22, Klinikum rechts der Isar, Technische Universitaet Muenchen, D-81675 Munich, Germany
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