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The Impact of Melatonin on Colon Cancer Cells' Resistance to Doxorubicin in an in Vitro Study. Int J Mol Sci 2017; 18:ijms18071396. [PMID: 28788434 PMCID: PMC5535889 DOI: 10.3390/ijms18071396] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/18/2017] [Accepted: 06/23/2017] [Indexed: 02/06/2023] Open
Abstract
Multi-drug resistance (MDR) is the main cause of low effectiveness of cancer chemotherapy. P-glycoprotein (P-gp) is one of the main factors determining MDR. Some studies indicate the potential role of melatonin (MLT) in MDR. In this study, we examined the effect of MLT on colon cancer cell’s resistance to doxorubicin (DOX). Using the sulforhodamine B (SRB), method the effect of tested substances on the survival of LoVo (colon cancer cells sensitive to DOX) and LoVoDX (colon cancer cells resistant to DOX) was rated. Using immunocytochemistry (ICC), the expression of P-gp in the LoVo and LoVoDX was determined. With the real-time PCR (RT-PCR) technique, the ABCB1 expression in LoVoDX was evaluated. Based on the results, it was found that MLT in some concentrations intensified the cytotoxicity effect of DOX in the LoVoDX cells. In the ICC studies, it was demonstrated that certain concentrations of MLT and DOX cause an increase in the percentage of cells expressing P-gp, which correlates positively with ABCB1 expression (RT-PCR). The mechanism of overcoming resistance by MLT is probably not only associated with the expression of P-gp. It seems appropriate to carry out further research on the use of MLT as the substance supporting cancer chemotherapy.
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Ng HY, Ko JMY, Yu VZ, Ip JCY, Dai W, Cal S, Lung ML. DESC1, a novel tumor suppressor, sensitizes cells to apoptosis by downregulating the EGFR/AKT pathway in esophageal squamous cell carcinoma. Int J Cancer 2016; 138:2940-51. [PMID: 26856390 DOI: 10.1002/ijc.30034] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 02/01/2016] [Indexed: 02/06/2023]
Abstract
Esophageal cancer is ranked as the eighth most common cancer and the sixth leading cause of cancer deaths worldwide. To identify candidate tumor suppressor genes related to esophageal squamous cell carcinoma (ESCC) development, a cDNA microarray analysis was performed using paired tumor and nontumor tissue samples from ESCC patients. Differentially expressed in squamous cell carcinoma 1 (DESC1), which belongs to the Type II transmembrane serine protease family, was frequently downregulated in ESCC. This study aims to elucidate the molecular mechanism for the tumor suppressive function of DESC1 in ESCC. We show that DESC1 reduced cell viability and sensitized cells to apoptosis, when cells were under apoptotic stimuli. The proapoptotic effect of DESC1 was mediated through downregulating AKT1 activation and the restoration of AKT activation by the introduction of the constitutively active AKT, myr-AKT, abolished the apoptosis-sensitizing effect of DESC1. DESC1 also reduced EGFR protein level, which was abrogated when the proteolytic function of DESC1 was lost, suggesting that DESC1 cleaved EGFR and downregulated the EGFR/AKT pathway to favor apoptosis. The transmembrane localization and the structural domains provide an opportunity for DESC1 to interact with the extracellular environment. The importance of such interaction was highlighted by the finding that DESC1 reduced cell colony formation ability in three-dimensional culture. In line with this, DESC1 reduced tumor growth kinetics in the in vivo orthotopic tumorigenesis assay. Taken together, our novel findings suggest how DESC1 may suppress ESCC development by sensitizing cells to apoptosis under an apoptotic stimulus through downregulating the EGFR/AKT signaling pathway.
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Affiliation(s)
- Hoi Yan Ng
- Department of Clinical Oncology, Faculty of Medicine, University of Hong Kong Li Ka Shing, Pokfulam, Hong Kong, SAR
| | - Josephine Mun-Yee Ko
- Department of Clinical Oncology, Faculty of Medicine, University of Hong Kong Li Ka Shing, Pokfulam, Hong Kong, SAR
| | - Valen Zhuoyou Yu
- Department of Clinical Oncology, Faculty of Medicine, University of Hong Kong Li Ka Shing, Pokfulam, Hong Kong, SAR
| | - Joseph Chok Yan Ip
- Department of Clinical Oncology, Faculty of Medicine, University of Hong Kong Li Ka Shing, Pokfulam, Hong Kong, SAR
| | - Wei Dai
- Department of Clinical Oncology, Faculty of Medicine, University of Hong Kong Li Ka Shing, Pokfulam, Hong Kong, SAR
| | - Santiago Cal
- Departamento De Bioquímica Y Biología Molecular, Instituto Universitario De Oncología, Universidad De Oviedo, Spain
| | - Maria Li Lung
- Department of Clinical Oncology, Faculty of Medicine, University of Hong Kong Li Ka Shing, Pokfulam, Hong Kong, SAR
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Prados J, Melguizo C, Roldan H, Alvarez PJ, Ortiz R, Arias JL, Aranega A. RNA interference in the treatment of colon cancer. BioDrugs 2014; 27:317-27. [PMID: 23553339 DOI: 10.1007/s40259-013-0019-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Colorectal cancer is the third most common cancer in both men and women and has shown a progressive increase over the past 20 years. Current chemotherapy has major limitations, and a novel therapeutic approach is required. Given that neoplastic transformation of colon epithelial cells is a consequence of genetic and epigenetic alterations, RNA interference (RNAi) has been proposed as a new therapeutic strategy that offers important advantages over conventional treatments, with high specificity and potency and low toxicity. RNAi has been employed as an effective tool to study the function of genes, preventing their expression and leading to the development of new approaches to cancer treatment. In malignancies, including colon cancer, RNAi is being used for "silencing" genes that are deregulated by different processes such as gene amplification, mutation, or overexpression and may be the cause of oncogenesis. This strategy not only provides information on the involvement of certain genes in colon cancer, but also opens up a new perspective for its treatment. However, most studies have used adenovirus or lentivirus vectors to transport RNAi into tumor cells or tumors in animal models, because several technical obstacles must be overcome before RNAi can be used in the clinical setting. The aim of this study was to review current knowledge on the use of RNAi techniques in the treatment of colon cancer.
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Affiliation(s)
- Jose Prados
- Institute of Biopathology and Regenerative Medicine, University of Granada, Spain
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Cbl-b enhances sensitivity to 5-fluorouracil via EGFR- and mitochondria-mediated pathways in gastric cancer cells. Int J Mol Sci 2013; 14:24399-411. [PMID: 24351824 PMCID: PMC3876118 DOI: 10.3390/ijms141224399] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/26/2013] [Accepted: 12/09/2013] [Indexed: 01/08/2023] Open
Abstract
5-Fluorouracil (5-FU) is an essential component of anticancer chemotherapy against gastric cancer. However, the response rate of single drug is still limited. The ubiquitin ligase Cbl-b is a negative regulator of growth factor receptor signaling and is involved in the suppression of cancer cell proliferation. However, whether Cbl-b could affect 5-FU sensitivity remains unclear. The present study showed that Cbl-b knockdown caused higher proliferation concomitant with the decrease of apoptosis induced by 5-FU treatment in gastric cancer cell. Further mechanism investigation demonstrated that Cbl-b knockdown caused significant increase of phosphorylation of EGFR, ERK and Akt, decrease of mitochondrial membrane potential, and increase of expression ratio of Bcl-2/Bax. These results suggest that Cbl-b enhances sensitivity to 5-FU via EGFR- and mitochondria-mediated pathways in gastric cancer cells.
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Chen X, Jiang W, Wang Q, Huang T, Wang P, Li Y, Chen X, Lv Y, Li X. Systematically characterizing and prioritizing chemosensitivity related gene based on Gene Ontology and protein interaction network. BMC Med Genomics 2012; 5:43. [PMID: 23031817 PMCID: PMC3532125 DOI: 10.1186/1755-8794-5-43] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 08/27/2012] [Indexed: 11/30/2022] Open
Abstract
Background The identification of genes that predict in vitro cellular chemosensitivity of cancer cells is of great importance. Chemosensitivity related genes (CRGs) have been widely utilized to guide clinical and cancer chemotherapy decisions. In addition, CRGs potentially share functional characteristics and network features in protein interaction networks (PPIN). Methods In this study, we proposed a method to identify CRGs based on Gene Ontology (GO) and PPIN. Firstly, we documented 150 pairs of drug-CCRG (curated chemosensitivity related gene) from 492 published papers. Secondly, we characterized CCRGs from the perspective of GO and PPIN. Thirdly, we prioritized CRGs based on CCRGs’ GO and network characteristics. Lastly, we evaluated the performance of the proposed method. Results We found that CCRG enriched GO terms were most often related to chemosensitivity and exhibited higher similarity scores compared to randomly selected genes. Moreover, CCRGs played key roles in maintaining the connectivity and controlling the information flow of PPINs. We then prioritized CRGs using CCRG enriched GO terms and CCRG network characteristics in order to obtain a database of predicted drug-CRGs that included 53 CRGs, 32 of which have been reported to affect susceptibility to drugs. Our proposed method identifies a greater number of drug-CCRGs, and drug-CCRGs are much more significantly enriched in predicted drug-CRGs, compared to a method based on the correlation of gene expression and drug activity. The mean area under ROC curve (AUC) for our method is 65.2%, whereas that for the traditional method is 55.2%. Conclusions Our method not only identifies CRGs with expression patterns strongly correlated with drug activity, but also identifies CRGs in which expression is weakly correlated with drug activity. This study provides the framework for the identification of signatures that predict in vitro cellular chemosensitivity and offers a valuable database for pharmacogenomics research.
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Affiliation(s)
- Xin Chen
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin 150081, China
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Galvin P, Thompson D, Ryan KB, McCarthy A, Moore AC, Burke CS, Dyson M, Maccraith BD, Gun'ko YK, Byrne MT, Volkov Y, Keely C, Keehan E, Howe M, Duffy C, MacLoughlin R. Nanoparticle-based drug delivery: case studies for cancer and cardiovascular applications. Cell Mol Life Sci 2012; 69:389-404. [PMID: 22015612 PMCID: PMC11115117 DOI: 10.1007/s00018-011-0856-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 09/29/2011] [Accepted: 09/29/2011] [Indexed: 11/25/2022]
Abstract
Nanoparticles (NPs) comprised of nanoengineered complexes are providing new opportunities for enabling targeted delivery of a range of therapeutics and combinations. A range of functionalities can be included within a nanoparticle complex, including surface chemistry that allows attachment of cell-specific ligands for targeted delivery, surface coatings to increase circulation times for enhanced bioavailability, specific materials on the surface or in the nanoparticle core that enable storage of a therapeutic cargo until the target site is reached, and materials sensitive to local or remote actuation cues that allow controlled delivery of therapeutics to the target cells. However, despite the potential benefits of NPs as smart drug delivery and diagnostic systems, much research is still required to evaluate potential toxicity issues related to the chemical properties of NP materials, as well as their size and shape. The need to validate each NP for safety and efficacy with each therapeutic compound or combination of therapeutics is an enormous challenge, which forces industry to focus mainly on those nanoparticle materials where data on safety and efficacy already exists, i.e., predominantly polymer NPs. However, the enhanced functionality affordable by inclusion of metallic materials as part of nanoengineered particles provides a wealth of new opportunity for innovation and new, more effective, and safer therapeutics for applications such as cancer and cardiovascular diseases, which require selective targeting of the therapeutic to maximize effectiveness while avoiding adverse effects on non-target tissues.
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Affiliation(s)
- Paul Galvin
- Tyndall National Institute, University College Cork, Cork, Ireland.
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Xu S, Weihua Z. Loss of EGFR induced autophagy sensitizes hormone refractory prostate cancer cells to adriamycin. Prostate 2011; 71:1216-24. [PMID: 21656832 DOI: 10.1002/pros.21337] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 12/09/2010] [Indexed: 02/03/2023]
Abstract
BACKGROUND The epidermal growth factor receptor (EGFR), a receptor tyrosine kinase, is over-expressed in advanced prostate cancer but tyrosine kinase inhibitors are not clinically effective in the treatment of prostate cancer. Recently it was found that EGFR in cancer cells has a kinase-independent pro-survival function, preventing cells from undergoing autophagy. In the present study we investigated whether the anti-autophagic function of EGFR may contribute to resistance of hormone-refractory prostate cancer cells to chemotherapeutic-induced apoptosis. METHODS We first characterized the autophagic phenotype induced by knocking down EGFR in hormone refractory prostate cancer cells (PC-3MM2 and DU-145), then we tested whether loss of EGFR-induced autophagy could sensitize cancer cells to adriamycin. RESULTS Using continuous live cell imaging techniques, we observed that knocking down EGFR lead to typical autophagic morphological/molecular changes, cell shrinkage without detachment, aggregation of microtubule-associated protein 1 light chain 3 (LC3) protein and absence of activation of apoptotic caspases 3/7. Loss of EGFR also increased the activity of calpain, which is pro-apoptotic. Knocking down EGFR, but not inhibiting its tyrosine kinase activity, significantly sensitized cells to adriamycin-induced apoptosis. Adriamycin-induced apoptosis could be inhibited by increased extracellular glucose level, suggesting intracellular glucose deficiency is a key mediator of the sensitization. The loss of EGFR induced autophagy and sensitization to adriamycin were also reproduced by using another hormone refractory prostate cancer cell line, Du145. CONCLUSION Taken together, these data suggest that decreasing the expression level of EGFR protein, rather than inhibiting its tyrosine kinase activity, may enhance the efficiency of EGFR targeted therapy for prostate cancer.
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Affiliation(s)
- Shuping Xu
- Department of Urology, University of Pittsburgh Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Wang L, Yu YH. EGFR-targeted drugs for colorectal cancer: current status and future challenges. Shijie Huaren Xiaohua Zazhi 2011; 19:1057-1062. [DOI: 10.11569/wcjd.v19.i10.1057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer is a common gastrointestinal malignancy. The effects of traditional chemotherapy and radiation therapy against colorectal cancer are not satisfactory. The epidermal growth factor receptor (EGFR) signaling pathway plays an important role in tumor proliferation, angiogenesis, invasion, and metastasis in colorectal cancer. EGFR-targeted drugs have been developed and applied to the treatment of colorectal cancer. This paper provides a literature review on the current status and future challenges of EGFR-targeted therapy of colorectal cancer.
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Cheng W, Wei Z, Gao J, Zhang Z, Ge J, Jing K, Xu F, Xie P. Effects of combined siRNA-TR and -TERT on telomerase activity and growth of bladder transitional cell cancer BIU-87 cells. ACTA ACUST UNITED AC 2010; 30:391-6. [PMID: 20556588 DOI: 10.1007/s11596-010-0363-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Indexed: 12/14/2022]
Abstract
The effects of combined RNA interference (RNAi) of human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) genes on telomerase activity in a bladder cancer cell line (BIU-87 cells) were investigated by using gene chip technology in vitro with an attempt to evaluate the role of RNAi in the gene therapy of bladder transitional cell cancer (BTCC). Three TR-specific double-stranded small interfering RNAs (siRNAs) and three TERT-specific double-stranded siRNAs were designed to target different regions of TR and TERT mRNA. The phTR-siRNA, phTERT-siRNA, and the combination of both plasmids phTR+phTERT-siRNA were transfected into BIU-87 cells. The expression of hTR and hTERT mRNA was detected by quantitative fluorescent reverse transcription-polymerase chain reaction, and a telomeric repeat amplification protocol was applied to detect telomerase activity. Growth inhibition of BIU-87 cells was measured by MTT assay. Gene chip analysis was performed to evaluate the effects of the combined RNAi of hTR+hTERT genes on telomerase activity and growth of BIU-87 cells in vitro. The results showed that the expression of hTERT and hTR mRNA was inhibited by pRNAT-hTERT-III, pRNAT-hTR-III, and pRNAT-hTR-III+hTERT-III in BIU-87 cells. The inhibition efficiency of pRNAT-hTERT-III, pRNAT-hTR-III, pRNAT-hTERT-III+pRNAT-hTR-III was 67% for TERT mRNA, 41% for TR mRNA, 57% for TR mRNA and 70% for TERT mRNA in BIU-87 cells respectively. The growth of BIU-87 cells was inhibited and telomerase activity was considerably decreased, especially in the cells treated with combined RNAi-hTR and -hTERT. Gene chip analysis revealed that 21 genes were down-regulated (ATM, BAX, BCL2, BCL2L1, BIRC5, CD44, CTNNB1, E2F1, JUN, MCAM, MTA1, MYC, NFKB1, NFKBIA, NME4, PNN, PNN, SERPINE1, THBS1, TNFRSF1A, and UCC1). The results indicated that hTR-siRNA and hTERT-siRNA, especially their combination, siRNA hTR+hTERT, specifically and effectively suppressed the expression of both hTR and hTERT mRNA and telomerase activity. Molecular biological mechanism by which combined siRNA-TR and -TERT inhibited telomerase activity and growth of BIU-87 cells in vitro may involve the down-regulation of the 21 genes.
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Affiliation(s)
- Wen Cheng
- Department of Urology, Jinling Hospital, Nanjing, 210002, China.
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Dickerson EB, Blackburn WH, Smith MH, Kapa LB, Lyon LA, McDonald JF. Chemosensitization of cancer cells by siRNA using targeted nanogel delivery. BMC Cancer 2010; 10:10. [PMID: 20064265 PMCID: PMC2820460 DOI: 10.1186/1471-2407-10-10] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Accepted: 01/11/2010] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Chemoresistance is a major obstacle in cancer treatment. Targeted therapies that enhance cancer cell sensitivity to chemotherapeutic agents have the potential to increase drug efficacy while reducing toxic effects on untargeted cells. Targeted cancer therapy by RNA interference (RNAi) is a relatively new approach that can be used to reversibly silence genes in vivo by selectively targeting genes such as the epidermal growth factor receptor (EGFR), which has been shown to increase the sensitivity of cancer cells to taxane chemotherapy. However, delivery represents the main hurdle for the broad development of RNAi therapeutics. METHODS We report here the use of core/shell hydrogel nanoparticles (nanogels) functionalized with peptides that specially target the EphA2 receptor to deliver small interfering RNAs (siRNAs) targeting EGFR. Expression of EGFR was determined by immunoblotting, and the effect of decreased EGFR expression on chemosensitization of ovarian cancer cells after siRNA delivery was investigated. RESULTS Treatment of EphA2 positive Hey cells with siRNA-loaded, peptide-targeted nanogels decreased EGFR expression levels and significantly increased the sensitivity of this cell line to docetaxel (P < 0.05). Nanogel treatment of SK-OV-3 cells, which are negative for EphA2 expression, failed to reduce EGFR levels and did not increase docetaxel sensitivity (P > 0.05). CONCLUSION This study suggests that targeted delivery of siRNAs by nanogels may be a promising strategy to increase the efficacy of chemotherapy drugs for the treatment of ovarian cancer. In addition, EphA2 is a viable target for therapeutic delivery, and the siRNAs are effectively protected by the nanogel carrier, overcoming the poor stability and uptake that has hindered clinical advancement of therapeutic siRNAs.
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Affiliation(s)
- Erin B Dickerson
- School of Biology, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332, USA
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Chen Y, Sen J, Bathula SR, Yang Q, Fittipaldi R, Huang L. Novel cationic lipid that delivers siRNA and enhances therapeutic effect in lung cancer cells. Mol Pharm 2009; 6:696-705. [PMID: 19267451 DOI: 10.1021/mp800136v] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We have developed lipid-polycation-DNA (LPD) nanoparticles containing DOTAP and targeted with polyethylene glycol (PEG) tethered with anisamide (AA) to specifically deliver siRNA to H460 human lung carcinoma cells which express the sigma receptor. A novel non-glycerol based cationic lipid which contains both a guanidinium and a lysine residue as the cationic headgroup, i.e. DSGLA, downregulated pERK more efficiently in H460 cells than DOTAP. As demonstrated by using fluorescently labeled siRNA, LPD-PEG-AA prepared with DSGLA efficiently delivered siRNA to the cytoplasm of the H460 cells. Although the siRNA delivered by LPD-PEG-AA containing either DOTAP or DSGLA could effectively silence EGFR expression, a synergistic cell killing effect in promoting cellular apoptosis was only observed with DSGLA. The fluorescently labeled siRNA was efficiently delivered into the cytoplasm of H460 xenograft tumor by the LPD-PEG-AA containing either DOTAP or DSGLA 4 h after intravenous injection. Three daily injections (0.6 mg/kg) of siRNA formulated in the LPD-PEG-AA containing either DOTAP or DSGLA could effectively silence the epidermal growth factor receptor (EGFR) in the tumor, but the formulation containing DSGLA could induce more cellular apoptosis. A significant improvement in tumor growth inhibition was observed after dosing with LPD-PEG-AA containing DSGLA. Thus, DSGLA served as both a formulation component as well as a therapeutic agent which synergistically enhanced the activity of siRNA.
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Affiliation(s)
- Yunching Chen
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Abstract
We have developed a self-assembled nanoparticle (NP) that efficiently delivers small interfering RNA (siRNA) to the tumor by intravenous (IV) administration. The NP was obtained by mixing carrier DNA, siRNA, protamine, and lipids, followed by post-modification with polyethylene glycol and a ligand, anisamide. Four hours after IV injection of the formulation into a xenograft model, 70-80% of injected siRNA/g accumulated in the tumor, approximately 10% was detected in the liver and approximately 20% recovered in the lung. Confocal microscopy showed that fluorescent-labeled siRNA was efficiently delivered into the cytoplasm of the sigma receptor expressing NCI-H460 xenograft tumor by the targeted NPs, whereas free siRNA and non-targeted NPs showed little uptake. Three daily injections (1.2 mg/kg) of siRNA formulated in the targeted NPs silenced the epidermal growth factor receptor (EGFR) in the tumor and induced approximately 15% tumor cell apoptosis. Forty percent tumor growth inhibition was achieved by treatment with targeted NPs, while complete inhibition lasted for 1 week when combined with cisplatin. The serum level of liver enzymes and body weight monitoring during the treatment indicated a low level of toxicity of the formulation. The carrier itself also showed little immunotoxicity (IMT).
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