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Peng R, Xu C, Zheng H, Lao X. Modified Thymosin Alpha 1 Distributes and Inhibits the Growth of Lung Cancer in Vivo. ACS OMEGA 2020; 5:10374-10381. [PMID: 32426594 PMCID: PMC7226852 DOI: 10.1021/acsomega.0c00220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
Targeted therapy of tumors is an effective method for treating cancer. Thymosin alpha 1 (Tα1), a hormone that contains 28 amino acids, is already approved for cancer treatment. However, its clinical application is limited because of the lack of tumor targeting. Considering that RGD can specifically bind to integrin, the anticancer drug can have a targeted therapeutic effect on tumors when it combines with a peptide containing an RGD sequence. We produced a polypeptide, Tα1-RGDR, by binding Tα1 to RGDR. The RGDR can combine with the αvβ3 and NRP-1 domains, which are highly expressed on the surface of the tumor, to achieve the effect of tumor targeting. This work aimed to investigate the difference of antitumor activity and tumor targeting between Tα1 modified by RGDR and Tα1 by using H460 and LLC tumor models. Results showed that Tα1-RGDR had remarkable antitumor effects, and its tumor targeting was better than that of Tα1. Hence, Tα1-RGDR is a promising antitumor drug.
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Affiliation(s)
- Renhao Peng
- Department of Life Science and Technology, China Pharmaceutical University, 211199 Nanjing, P. R. China
| | - Caoying Xu
- Department of Life Science and Technology, China Pharmaceutical University, 211199 Nanjing, P. R. China
| | - Heng Zheng
- Department of Life Science and Technology, China Pharmaceutical University, 211199 Nanjing, P. R. China
| | - Xingzhen Lao
- Department of Life Science and Technology, China Pharmaceutical University, 211199 Nanjing, P. R. China
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Development of a Highly Efficient Hybrid Peptide That Increases Immunomodulatory Activity Via the TLR4-Mediated Nuclear Factor-κB Signaling Pathway. Int J Mol Sci 2019; 20:ijms20246161. [PMID: 31817671 PMCID: PMC6940896 DOI: 10.3390/ijms20246161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 02/07/2023] Open
Abstract
Immunity is a defensive response that fights disease by identifying and destroying harmful substances or microbiological toxins. Several factors, including work-related stress, pollution, and immunosuppressive agents, contribute to low immunity and poor health. Native peptides, a new class of immunoregulatory agents, have the potential for treating immunodeficiencies, malignancies, and infections. However, the potential cytotoxicity and low immunoregulatory activity and stability of native peptides have prevented their development. Therefore, we designed three hybrid peptides (LTAa, LTAb, and LTAc) by combining a characteristic fragment of LL-37 with an active Tα1 center that included Tα1 (17-24), Tα1 (20-25), and Tα1 (20-27). The best hybrid peptide (LTAa), according to molecule docking and in vitro experiments, had improved immunoregulatory activity and stability with minimal cytotoxicity. We investigated the immunoregulatory effects and mechanisms of LTAa using a cyclophosphamide-immunosuppressed murine model. LTAa effectively reversed immunosuppression by enhancing immune organ development, activating peritoneal macrophage phagocytosis, regulating T lymphocyte subsets, and increasing cytokine (tumor necrosis factor-alpha, interleukin-6, and interleukin-1β) and immunoglobulin (IgA, IgG, and IgM) contents. The immunomodulatory effects of LTAa may be associated with binding to the TLR4/MD-2 complex and activation of the NF-κB signaling pathway. Therefore, LTAa could be an effective therapeutic agent for improving immune function.
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Wang F, Yu T, Zheng H, Lao X. Thymosin Alpha1-Fc Modulates the Immune System and Down-regulates the Progression of Melanoma and Breast Cancer with a Prolonged Half-life. Sci Rep 2018; 8:12351. [PMID: 30120362 PMCID: PMC6097990 DOI: 10.1038/s41598-018-30956-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 08/08/2018] [Indexed: 02/06/2023] Open
Abstract
Thymosin alpha 1 (Tα1) is a biological response modifier that has been introduced into markets for treating several diseases. Given the short serum half-life of Tα1 and the rapid development of Fc fusion proteins, we used genetic engineering method to construct the recombinant plasmid to express Tα1-Fc (Fc domain of human IgG4) fusion protein. A single-factor experiment was performed with different inducers of varying concentrations for different times to get the optimal condition of induced expression. Pure proteins higher than 90.3% were obtained by using 5 mM lactose for 4 h with a final production about 160.4 mg/L. The in vivo serum half-life of Tα1-Fc is 25 h, almost 13 times longer than Tα1 in mice models. Also, the long-acting protein has a stronger activity in repairing immune injury through increasing number of lymphocytes. Tα1-Fc displayed a more effective antitumor activity in the 4T1 and B16F10 tumor xenograft models by upregulating CD86 expression, secreting IFN-γ and IL-2, and increasing the number of tumor-infiltrating CD4+ T and CD8+ T cells. Our study on the novel modified Tα1 with the Fc segment provides valuable information for the development of new immunotherapy in cancer.
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Affiliation(s)
- Fanwen Wang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009, P.R. China
| | - Tingting Yu
- Dongyangguang pharmaceutical r&d co. LTD, Dongguan, 523000, P.R. China
| | - Heng Zheng
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009, P.R. China.
| | - Xingzhen Lao
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009, P.R. China.
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Wang F, Xu C, Peng R, Li B, Shen X, Zheng H, Lao X. Effect of a C-end rule modification on antitumor activity of thymosin α1. Biochimie 2018; 154:99-106. [PMID: 30096371 DOI: 10.1016/j.biochi.2018.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 08/04/2018] [Indexed: 12/27/2022]
Abstract
Thymosin α1 (Tα1), a hormone containing 28 amino acids, has been approved in several cancer therapies, but the lack of tumor-targeting hinders its full use in tumor treatment. We designed a new peptide by connecting Tα1 and RGDR, generating a product, Tα1-RGDR, where RGDR is located in the C-end with both tumor-homing and cell internalizing properties (C-end rule peptides, a consensus R/KXXR/K motif). This work aimed to study the antitumor and immunological activities of Tα1-RGDR, and its differences compared with the wild-type Tα1. The antitumor and immunological activities of Tα1-RGDR were measured using the B16F10 tumor and immunologic suppression models. Tα1-RGDR treatment led to significant inhibition of tumor growth at a dose at which Tα1 showed a slight effect in the B16F10 tumor growth model. In the immunologic suppression model, Tα1-RGDR shared almost equivalent immunomodulatory effect with Tα1. These results demonstrated the better therapeutic effects after treatment with Tα1-RGDR compared with Tα1. Moreover, both Tα1-RGDR and Tα1 shared a helical conformation in the presence of trifluoroethanol based on CD spectroscopy. Our dock information of Tα1-RGDR when combined with integrin αvβ3 or neuropilin-1 further confirmed previous experimental results. All these findings suggest that Tα1-RGDR might be a useful therapy for tumors by overcoming its wild type limitation of tumor homing.
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Affiliation(s)
- Fanwen Wang
- School of Life Science and Technology, China Pharmaceutical University, 24 Tongjiaxiang 24, Nanjing, 210009, China
| | - Caoying Xu
- School of Life Science and Technology, China Pharmaceutical University, 24 Tongjiaxiang 24, Nanjing, 210009, China
| | - Renhao Peng
- School of Life Science and Technology, China Pharmaceutical University, 24 Tongjiaxiang 24, Nanjing, 210009, China
| | - Bin Li
- School of Life Science and Technology, China Pharmaceutical University, 24 Tongjiaxiang 24, Nanjing, 210009, China
| | - Xutong Shen
- School of Life Science and Technology, China Pharmaceutical University, 24 Tongjiaxiang 24, Nanjing, 210009, China
| | - Heng Zheng
- School of Life Science and Technology, China Pharmaceutical University, 24 Tongjiaxiang 24, Nanjing, 210009, China
| | - Xingzhen Lao
- School of Life Science and Technology, China Pharmaceutical University, 24 Tongjiaxiang 24, Nanjing, 210009, China.
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Wang F, Li B, Fu P, Li Q, Zheng H, Lao X. Effects on tumor growth and immunosuppression of a modified Tα1 peptide along with its circular dichroism spectroscopy data. Data Brief 2018; 20:126-131. [PMID: 30109250 PMCID: PMC6088563 DOI: 10.1016/j.dib.2018.07.058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/01/2018] [Accepted: 07/24/2018] [Indexed: 11/18/2022] Open
Abstract
The data presented in this article are related to the research article entitled "Immunomodulatory and Enhanced Antitumor Activity of a Modified Thymosin α1 in Melanoma and Lung Cancer" (Wang et al., 2018). Tα1 has been evaluated as effective in cancer treatment. In order to make it capable to target tumor, a peptide iRGD was introduced to Tα1. The anti-tumor activity was accessed by constructing in vivo melanoma and human non-small-cell lung cancer models treated with Tα1-iRGD to measure the tumor volume over time and tumor weight at the last day. The concentration of IFN-γ and IL-2 in C57BL/6 mice peripheral blood was determined by ELISA. And the immunomodulatory ability of Tα1-iRGD was evaluated in vivo by thymus index and spleen index. Those functions this paper was aimed at may have relationship with its secondary structure, so the circular dichroism spectra of Tα1, iRGD and Tα1-iRGD was performed.
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Affiliation(s)
- Fanwen Wang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Bin Li
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Pengcheng Fu
- Department of Neurology, the First People׳s Hospital of Chenzhou, Hunan 423000, PR China
| | - Qingqing Li
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Heng Zheng
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Xingzhen Lao
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
- Corresponding author. Tel: 86-25-83271001, Fax: 86-25-83271249.
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Wang F, Li B, Fu P, Li Q, Zheng H, Lao X. Immunomodulatory and enhanced antitumor activity of a modified thymosin α1 in melanoma and lung cancer. Int J Pharm 2018; 547:611-620. [PMID: 29933059 DOI: 10.1016/j.ijpharm.2018.06.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/28/2018] [Accepted: 06/18/2018] [Indexed: 12/22/2022]
Abstract
Tumor-targeted therapy is an attractive strategy for cancer treatment. Peptide hormone thymosin α1 (Tα1) has been used against several diseases, including cancer, but its activity is pleiotropic. Herein, we designed a fusion protein Tα1-iRGD by introducing the tumor homing peptide iRGD to Tα1. Results show that Tα1-iRGD can promote T-cell activation and CD86 expression, thereby exerting better effect and stronger inhibitory against melanoma and lung cancer, respectively, than Tα1 in vivo. These effects are indicated by the reduced densities of tumor vessels and Tα1-iRGD accumulation in tumors. Moreover, compared with Tα1, Tα1-iRGD can attach more B16F10 and H460 cells and exhibits significantly better immunomodulatory activity in immunosuppression models induced by hydrocortisone. Circular dichroism spectroscopy and structural analysis results revealed that Tα1 and Tα1-iRGD both adopted a helical confirmation in the presence of trifluoroethanol, indicating the structural basis of their functions. These findings highlight the vital function of Tα1-iRGD in tumor-targeted therapy and suggest that Tα1-iRGD is a better antitumor drug than Tα1.
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Affiliation(s)
- Fanwen Wang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Bin Li
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Pengcheng Fu
- Department of Neurology, The First People's Hospital of Chenzhou, Hunan 423000, PR China
| | - Qingqing Li
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Heng Zheng
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Xingzhen Lao
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China.
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Li J, Cheng Y, Zhang X, Zheng L, Han Z, Li P, Xiao Y, Zhang Q, Wang F. The in vivo immunomodulatory and synergistic anti-tumor activity of thymosin α1-thymopentin fusion peptide and its binding to TLR2. Cancer Lett 2013; 337:237-47. [PMID: 23684552 DOI: 10.1016/j.canlet.2013.05.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/01/2013] [Accepted: 05/04/2013] [Indexed: 10/26/2022]
Abstract
In the present study, the immunomodulatory and synergistic anti-tumor activity of thymosin α1-thymopentin fusion peptide (Tα1-TP5) was investigated in vivo. In addition, the potential receptor of Tα1-TP5 was investigated by surface plasmon resonance (SPR) binding studies. It was found that Tα1-TP5 (305 μg/kg) alleviated immunosuppression induced by hydrocortisone (HC). Tα1-TP5 (305 μg/kg) combined with cyclophosphamide (CY) had a better tumor growth inhibitory effect than CY alone. Furthermore, Tα1-TP5 had a higher affinity (KD=6.84 μmol/L) to toll-like receptor 2 (TLR2) than Tα1 (K(D)=35.4 μmol/L), but its affinity was not significantly different from that of TP5. The results of our present work indicate that Tα1-TP5 can possibly be developed as a new immunomodulatory agent.
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Affiliation(s)
- Juan Li
- Key Laboratory of Chemical Biology of Natural Products, Ministry of Education, Institute of Biochemical and Biotechnological Drugs, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
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Li W, Song L, Wu S, Xue X, Zhang L, He L, Han W, Wang Q, Ling R, Zhang W, Yan Z, Zhang Y. Expression, purification and characterization of a novel soluble human thymosin alpha1 concatemer exhibited a stronger stimulation on mice lymphocytes proliferation and higher anti-tumor activity. Int J Biol Sci 2011; 7:618-28. [PMID: 21647330 PMCID: PMC3107470 DOI: 10.7150/ijbs.7.618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 05/04/2011] [Indexed: 12/29/2022] Open
Abstract
Thymosin alpha 1 (Tα1) has immunomodulatory and anti-tumor effects in patients and has been commercialized in worldwide. An innovative technique is therefore impending to achieve high-yield expression and purification of Tα1 to meet the increasing requirements for clinical applications. Tα1 can enhance T cells, dendritic cells and antibody responses, and also augment an anti-tumor immune response. In the current study, we developed a novel technique to produce Tα1 concatemer and investigated its capability in anti-tumor immunotherapy. We expressed the recombinant 2×Tα1 concatemer protein (Tα1② protein) in Escherichia coli. The purity of Tα1② was higher than 95% as assessed by HPLC analysis. In vitro, Tα1② could stimulate the proliferation of mouse splenic lymphocyte, and increase the apoptosis of tumor cell lines. In vivo, Tα1② significantly inhibited the tumor growth in B16 tumor-bearing mice. Compared with Tα1, the Tα1② is of more effective bioactivity than Tα1. The purified Tα1② is a promising substitute for synthetic Tα1 because of its potent anti-tumor effects. We concluded that the expression system for Tα1 concatemer was constructed successfully, which could serves as a highly efficient tool for the production of large quantities of the highly active protein.
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Affiliation(s)
- Weina Li
- The State Key Laboratory of Cancer Biology, Department of Biopharmaceutics, School of Pharmacy, Fourth Military Medical University, 710032 Xi'an, China
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Shibuya TY, Kim S, Nguyen K, Parikh P, Wadhwa A, Brockardt C, Do J. Covalent linking of proteins and cytokines to suture: Enhancing the immune response of head and neck cancer patients. Laryngoscope 2010; 113:1870-84. [PMID: 14603040 DOI: 10.1097/00005537-200311000-00004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The immune system of advanced stage head and neck cancer patients is frequently suppressed. Poor immune function has been correlated with poor clinical outcome. Immunotherapeutic strategies have been previously attempted in an effort to enhance immune function and improve survival. Previous studies have shown surgical suture can be transformed into an immune stimulant capable of activating the T lymphocytes of cancer patients. The development of a process for covalently linking proteins and cytokines to suture could have enormous potential for the in vivo manipulation of the immune system. HYPOTHESIS We hypothesize proteins and cytokines can be covalently linked to surgical suture while preserving their functional properties. STUDY DESIGN Prospective study testing normal donor and head and neck squamous cell carcinoma (HNSCC) patient lymphocytes. METHOD Polyester suture was acid hydrolyzed followed by reacting with 1-ethyl-3(-3-dimethylamino propyl carbodiimide) (EDAC) to create a suture-EDAC intermediate. Next, selected proteins (horseradish peroxidase [HRP] or bovine serum albumin [BSA]) or cytokines (interleukin [IL]-2 or interferon [IFN]-gamma) were reacted with the suture-EDAC intermediate to test the covalent linkage of the selected protein or cytokine to suture. Functional activity of the linked proteins was measured spectrophotometrically. The linking of cytokines to suture was tested by stimulating normal donor peripheral blood lymphocytes (PBL) or HNSCC patients' lymphocytes. The functional activity was confirmed by proliferation, enzyme linked immunoadsorbent assay (ELISA), and phenotype expression of T cells. RESULTS The conditions for optimally linking a protein to polyester suture were defined using HRP as a model protein. HRP retained its enzymatic activity. The optimal conditions for linking IL-2 or IFN-gamma were defined. The covalently linked cytokines retained their immune enhancing properties for stimulating PBL and lymph node lymphocytes (LNL) from HNSCC patients to proliferate, generate a TH1 immunologic profile of cytokines (IL-2, IL-12, IFN-gamma), and stimulate T lymphocytes. CONCLUSION This is the first report to demonstrate that cytokines can be covalently linked to surgical sutures and retain their immune-stimulating properties. Proteins linked to suture also retained their enzymatic activity. The clinical implications of functionally active cytokines or proteins linked to surgical suture may be very significant in the future for manipulating the immune system in vivo or enhancing wound healing.
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Affiliation(s)
- Terry Y Shibuya
- Department of Otolaryngology/Head and Neck Surgery, University of California Irvine College of Medicine, Orange 92868, USA.
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Chen JH, Zhang XG, Jiang YT, Yan LY, Tang L, Yin YW, Cheng DS, Chen J, Wang M. Bioactivity and pharmacokinetics of two human serum albumin-thymosin alpha1-fusion proteins, rHSA-Talpha1 and rHSA-L-Talpha1, expressed in recombinant Pichia pastoris. Cancer Immunol Immunother 2010; 59:1335-45. [PMID: 20473755 PMCID: PMC11030058 DOI: 10.1007/s00262-010-0862-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Accepted: 04/26/2010] [Indexed: 12/22/2022]
Abstract
Thymosin-alpha1 (Talpha1) is indicated for the treatment of certain viral infections, including hepatitis B and C, and cancers, such as melanoma. In this paper, the fusion genes encoding human serum albumin (HSA) and Talpha1 with (rHSA-L-Talpha1) and without a linker peptide (rHSA-Talpha1) were constructed and overexpressed in P. pastoris. Through the process of ion interaction chromatography (Q-Sepharose F.F), hydrophobic interaction chromatography (Phenyl Sepharose HP) and affinity chromatography (Blue Sepharose F.F), the purity of fusion proteins was greater than 97%. In contrast to the reactivity of normal spleen cells to Con A, the data of in vitro murine spleen lymphocytes proliferation experiment suggested that spleen cells achieved a higher degree of T cell maturation after rHSA-L-Talpha1, rHSA-Talpha1 and Talpha1 treatments, respectively. Moreover, rHSA-L-Talpha1, rHSA-Talpha1 and Talpha1 can also antagonize dexamethasone-induced apoptosis of thymocyte sub-populations. In hydrocortisone-induced immunosuppression mice (in vivo experiments), after subcutaneous injections with two fusion proteins and Talpha1 for seven consecutive days, the net increment of body weight, the spleen index and the thymus index were significantly improved. Simultaneously, the increase in SOD level and the decrease in MDA level in plasma were observed. The pharmacokinetic data of rHSA-L-Talpha1 and rHSA-Talpha1 administered in rats showed an improved pharmacokinetic profile with a conspicuous prolonged half life. The analysis of bioactivity and pharmacokinetics suggested that fusion proteins rHSA-L-Talpha1 and rHSA-Talpha1 were new drug candidates.
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Affiliation(s)
- Jian-Hua Chen
- College of Life Science and Technology, China Pharmaceutical University, Nanjing, People's Republic of China.
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Thymosin-alpha1 modulates dendritic cell differentiation and functional maturation from human peripheral blood CD14+ monocytes. Immunol Lett 2007; 110:110-20. [PMID: 17532057 DOI: 10.1016/j.imlet.2007.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 04/09/2007] [Accepted: 04/12/2007] [Indexed: 11/18/2022]
Abstract
Although thymosins have been demonstrated to have immunomodulatory effects, it is still not clear whether they could affect dendritic cells (DCs), the most professional antigen-presenting cells. The objective of this study was to determine the effect and potential mechanisms of thymosin-alpha1 (Talpha1) on DC differentiation and functional maturation. Human peripheral blood CD14(+) monocytes were purified by using a magnetic separation column and cultured with GM-CSF and IL-4 to differentiate into immature DCs (iDCs). In the presence of Talpha1, iDC surface markers CD40, CD80, MHC class I and class II molecules were significantly upregulated as measured by flow cytemotry analysis. However, Tbeta4 or Tbeta10 did not show these effects on iDCs. There was an approximately 30% reduction in antigen (FITC-conjugated dextran)-uptake by Talpha1-treated iDCs as compared with non-Talpha1-treated iDCs. In addition, Talpha1-treated matured DCs (mDCs) showed an increased stimulation of allogeneic CD3(+) T-cell proliferation as measured by a mixed-lymphocyte reaction assay. Talpha1-treated mDCs also increased the production of several Th1- and Th2-type cytokines as measured by a Bio-Plex cytokine assay. Furthermore, rapid activation of p38 MAPK and NFkappaB was seen in Talpha1-treated iDCs as measured by a Bio-Plex phosphoprotein assay. Thus, Talpha1 significantly enhances DC differentiation, activation, and functions from human peripheral blood CD14(+) monocytes possibly through a mechanism of the activation of p38 MAPK and NFkappaB pathways. This study provides a basis to further evaluate Talpha1 as a possible adjuvant for a DC-directed vaccine or therapy.
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Abstract
T alpha 1, a 28-amino-acid peptide, is derived from PT alpha, which is an intracellular, nonsecretory protein of unknown function. Both T alpha 1 and PT alpha are found in the blood of normal individuals. Subcutaneous and intramuscular injections of T alpha 1 in doses up to 9.6 mg/m2 are tolerated without side effects, and 0.9 mg/m2 injections raise the serum level approximately 30-fold after 1 hr of administration, which slowly returns to baseline within 24 hr. In vitro, and perhaps in vivo, T alpha 1 restores normal T-cell function. It increases IL-2 production and IL-2 receptors in normal mitogen-stimulated T cells and stimulates IL-3 production in immunocompromised mice. The dose-response relationship for these effects is not linear and may be bimodal. T alpha 1 binds to VIP receptors and inhibits in vitro and xenograft growth of non-SCLC cell lines. In patients with nonbulky carcinomas who have received standard therapy, T alpha 1 is possibly effective in prolonging the time to relapse and in improving survival. At present there is a great need to clearly define the clinical role of T alpha 1 in cancer patients. A major problem encountered in studies with T alpha 1 will, however, be the present lack of knowledge with regard to its mechanism in effecting tumor growth. It is not at all clear whether its immunomodulatory functions, its interaction with VIP receptors, or none of these mechanisms are related to its antineoplastic activities. In addition, the apparent nonlinear dose-response relationship will make it difficult to choose a reasonable dosing schedule for clinical trials. This is particularly apparent in light of the experimental animal data summarized above where a tumor response was seen at doses of 4 micrograms/kg and 400 micrograms/kg but not at 0.4 microgram/kg and 40 micrograms/kg. This dose range could conceivably be given to humans since 9.6 mg/m2, the maximum dose given to humans without major side effects to date, is roughly equivalent to 250 micrograms/kg. At this time a reasonable clinical approach would be a well-designed risk factor stratified phase III clinical trial using 0.9 mg/m2 T alpha 1 subcutaneously twice a week compared to a control group to substantiate the data reported by Schulof et al. Before such data are available, T alpha 1 should not be used in clinical oncology.
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Affiliation(s)
- G Bepler
- Department of Medicine, Duke University Medical Center, Durham, North Carolina
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