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Singh RK, Kumar S, Tomar MS, Verma PK, Kumar A, Kumar S, Kumar N, Singh JP, Acharya A. Putative role of natural products as Protein Kinase C modulator in different disease conditions. ACTA ACUST UNITED AC 2021; 29:397-414. [PMID: 34216003 DOI: 10.1007/s40199-021-00401-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 05/25/2021] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Protein kinase C (PKC) is a promising drug target for various therapeutic areas. Natural products derived from plants, animals, microorganisms, and marine organisms have been used by humans as medicine from prehistoric times. Recently, several compounds derived from plants have been found to modulate PKC activities through competitive binding with ATP binding site, and other allosteric regions of PKC. As a result fresh race has been started in academia and pharmaceutical companies to develop an effective naturally derived small-molecule inhibitor to target PKC activities. Herein, in this review, we have discussed several natural products and their derivatives, which are reported to have an impact on PKC signaling cascade. METHODS All information presented in this review article regarding the regulation of PKC by natural products has been acquired by a systematic search of various electronic databases, including ScienceDirect, Scopus, Google Scholar, Web of science, ResearchGate, and PubMed. The keywords PKC, natural products, curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, protocatechuic acid, tannic acid, PKC modulators from marine organism, bryostatin, staurosporine, midostaurin, sangivamycin, and other relevant key words were explored. RESULTS The natural products and their derivatives including curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, bryostatin, staurosporine, and midostaurin play a major role in the management of PKC activity during various disease progression. CONCLUSION Based on the comprehensive literature survey, it could be concluded that various natural products can regulate PKC activity during disease progression. However, extensive research is needed to circumvent the challenge of isoform specific regulation of PKC by natural products.
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Affiliation(s)
- Rishi Kant Singh
- Department of Zoology, Institute of Science, BHU, Varanasi, 221005, India
| | | | - Munendra Singh Tomar
- Department of Pharmaceutical Science, School of Pharmacy, University of Colorado, Denver, USA
| | | | - Amit Kumar
- Department of Zoology, Institute of Science, BHU, Varanasi, 221005, India
| | - Sandeep Kumar
- Department of Zoology, Institute of Science, BHU, Varanasi, 221005, India
| | - Naveen Kumar
- Department of Zoology, Institute of Science, BHU, Varanasi, 221005, India
| | - Jai Prakash Singh
- Department of Panchkarma, Institute of Medical Science, BHU, Varanasi, India, 221005
| | - Arbind Acharya
- Department of Zoology, Institute of Science, BHU, Varanasi, 221005, India.
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Zhi J, Zhang P, Zhang W, Ruan X, Tian M, Guo S, Zhang W, Zheng X, Zhao L, Gao M. Inhibition of BRAF Sensitizes Thyroid Carcinoma to Immunotherapy by Enhancing tsMHCII-mediated Immune Recognition. J Clin Endocrinol Metab 2021; 106:91-107. [PMID: 32936899 DOI: 10.1210/clinem/dgaa656] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 09/14/2020] [Indexed: 12/28/2022]
Abstract
CONTEXT Multiple mechanisms play roles in restricting the ability of T-cells to recognize and eliminate tumor cells. OBJECTIVE To identify immune escape mechanisms involved in papillary thyroid carcinoma (PTC) to optimize immunotherapy. SETTING AND DESIGN iTRAQ analysis was conducted to identify proteins differentially expressed in PTC samples with or without BRAFV600E mutation. Molecular mechanisms regulating tumor cell evasion were investigated by in vitro modulations of BRAF/MAPK and related pathways. The pathological significance of identified tumor-specific major histocompatibility complex class II (tsMHCII) molecules in mediating tumor cell immune escape and targeted immune therapy was further evaluated in a transgenic mouse model of spontaneous thyroid cancer. RESULTS Proteomic analysis showed that tsMHCII level was significantly lower in BRAFV600E-associated PTCs and negatively correlated with BRAF mutation status. Constitutive activation of BRAF decreased tsMHCII surface expression on tumor cells, which inhibited activation of CD4+ T-cells and led to immune escape. Pathway analysis indicated that the transforming growth factor (TGF)-β1/SMAD3-mediated repression of tsMHCII, which could be reversed by BRAF inhibition (BRAFi). Targeting this pathway with a combined therapy of BRAF inhibitor PLX4032 and anti-PD-1 antibody efficiently blocked tumor growth by increasing CD4+ T-cell infiltration in a transgenic PTC mouse model. CONCLUSIONS Our results suggest that BRAFV600E mutation in PTC impairs the expression of tsMHCII through the TGF-β1/SMAD3 pathway to enhance immune escape. Combined treatment with PLX4032 and anti-PD-1 antibody promotes recognition and elimination of PTC by the immune system in a pre-clinical mouse model, and therefore offers an effective therapeutic strategy for patients with advanced PTC.
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MESH Headings
- Animals
- Antineoplastic Agents, Immunological/administration & dosage
- Antineoplastic Agents, Immunological/pharmacology
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- CD4-Positive T-Lymphocytes/drug effects
- CD4-Positive T-Lymphocytes/physiology
- Cells, Cultured
- Cytotoxicity, Immunologic/drug effects
- Cytotoxicity, Immunologic/genetics
- Cytotoxicity, Immunologic/immunology
- Drug Synergism
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Expression Regulation, Neoplastic/immunology
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/physiology
- Humans
- Immunotherapy/methods
- Lymphocyte Activation/drug effects
- Lymphocyte Activation/genetics
- Mice
- Mice, Transgenic
- Mutant Proteins/antagonists & inhibitors
- Mutation, Missense
- Nivolumab/administration & dosage
- Nivolumab/pharmacology
- Organ Specificity/genetics
- Organ Specificity/immunology
- Protein Kinase Inhibitors/administration & dosage
- Protein Kinase Inhibitors/pharmacology
- Proto-Oncogene Proteins B-raf/antagonists & inhibitors
- Proto-Oncogene Proteins B-raf/genetics
- Thyroid Cancer, Papillary/drug therapy
- Thyroid Cancer, Papillary/genetics
- Thyroid Cancer, Papillary/immunology
- Thyroid Cancer, Papillary/pathology
- Thyroid Neoplasms/drug therapy
- Thyroid Neoplasms/genetics
- Thyroid Neoplasms/immunology
- Thyroid Neoplasms/pathology
- Tumor Escape/drug effects
- Tumor Escape/genetics
- Tumor Escape/immunology
- Vemurafenib/administration & dosage
- Vemurafenib/pharmacology
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Affiliation(s)
- Jingtai Zhi
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Peitao Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, People's Republic of China
| | - Wei Zhang
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Xianhui Ruan
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Mengran Tian
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Shicheng Guo
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin
- Center for Precision Medicine Research, Marshfield Clinic Research Institute, Marshfield, Wisconsin
| | - Weiyu Zhang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, People's Republic of China
- College of Pharmacy, Nankai University, Tianjin, People's Republic of China
| | - Xiangqian Zheng
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Li Zhao
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, People's Republic of China
| | - Ming Gao
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
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Wang L, Wang Y, Lu Y, Zhang Q, Qu X. Heterozygous deletion of ATG5 in Apc(Min/+) mice promotes intestinal adenoma growth and enhances the antitumor efficacy of interferon-gamma. Cancer Biol Ther 2016; 16:383-91. [PMID: 25695667 DOI: 10.1080/15384047.2014.1002331] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Autophagy related gene 5 (ATG5) was lost in 23% of the patients with colorectal cancer (CRC) and the role of loss of ATG5 in the pathogenesis of CRC remains unclear. Knockdown of ATG5 in cancer cells enhances the antitumor efficacy of lots of chemotherapeutic agents. However, there is still no animal model to validate these in vitro observations in vivo. In this study, we found that heterozygous deletion of ATG5 in Apc(Min/+) mice increased the number and size of adenomas as compared with those in Apc(Min/+)ATG5(+/+) mice. To investigate whether ATG5 deficiency could sensitize tumors to chemotherapies, we compared the antitumor effects of Interferon-gamma (IFN-γ) between Apc(Min/+)ATG5(+/+) and Apc(Min/+)ATG5(+/-) mice, as IFN-γ is a potential tumor suppressor for CRC and has been used clinically as an efficient adjuvant to chemotherapy of cancer. We revealed that heterozygous deletion of ATG5 significantly enhanced the antitumor efficacy of IFN-γ. Early treatment of Apc(Min/+)ATG5(+/-) mice with IFN-γ decreased tumor incidence rate to 16.7% and reduced the number of adenomas by 95.5% and late treatment led to regression of tumor. Moreover, IFN-γ treatment did not cause any evident toxic reaction. Mechanistic analysis revealed that heterozygous deletion of ATG5 activated EGFR/ERK1/2 and Wnt/β-catenin pathways in adenomas of Apc(Min/+) mice and enhanced the effects of IFN-γ-dependent inhibition of these 2 pathways. Our results demonstrate that ATG5 plays important roles in intestinal tumor growth and combination of IFN-γ and ATG5 deficiency or ATG5-targeted inhibition is a promising strategy for prevention and treatment of CRC.
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Key Words
- 5-FU, 5-fluorouracil
- ATG5
- ATG5, autophagy related gene 5
- Apc, adenomatous polyposis coli
- ApcMin/+ mouse
- CRC, colorectal cancer
- EGFR, epidermal growth factor receptor
- Erk, extracellular signal-regulated kinase
- IFN-γ
- IFN-γ, Interferon-gamma
- LC3, microtubule-associated protein 1 light chain 3
- PCNA, proliferating cell nuclear antigen
- colorectal cancer
- heterozygous deletion
- intestinal adenoma
- siRNAs, small interfering RNAs
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Affiliation(s)
- Lu Wang
- a Department of Pharmacology; School of Pharmaceutical Sciences ; Shandong University ; Jinan , Shandong , China
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Radhakrishnan EK, Bava SV, Narayanan SS, Nath LR, Thulasidasan AKT, Soniya EV, Anto RJ. [6]-Gingerol induces caspase-dependent apoptosis and prevents PMA-induced proliferation in colon cancer cells by inhibiting MAPK/AP-1 signaling. PLoS One 2014; 9:e104401. [PMID: 25157570 PMCID: PMC4144808 DOI: 10.1371/journal.pone.0104401] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 07/13/2014] [Indexed: 02/05/2023] Open
Abstract
We report mechanism-based evidence for the anticancer and chemopreventive efficacy of [6]-gingerol, the major active principle of the medicinal plant, Ginger (Zingiber officinale), in colon cancer cells. The compound was evaluated in two human colon cancer cell lines for its cytotoxic effect and the most sensitive cell line, SW-480, was selected for the mechanistic evaluation of its anticancer and chemopreventive efficacy. The non-toxic nature of [6]-gingerol was confirmed by viability assays on rapidly dividing normal mouse colon cells. [6]-gingerol inhibited cell proliferation and induced apoptosis as evidenced by externalization of phosphatidyl serine in SW-480, while the normal colon cells were unaffected. Sensitivity to [6]-gingerol in SW-480 cells was associated with activation of caspases 8, 9, 3 &7 and cleavage of PARP, which attests induction of apoptotic cell death. Mechanistically, [6]-gingerol down-regulated Phorbol Myristate Acetate (PMA) induced phosphorylation of ERK1/2 and JNK MAP kinases and activation of AP-1 transcription factor, but had only little effects on phosphorylation of p38 MAP kinase and activation of NF-kappa B. Additionally, it complemented the inhibitors of either ERK1/2 or JNK MAP kinase in bringing down the PMA-induced cell proliferation in SW-480 cells. We report the inhibition of ERK1/2/JNK/AP-1 pathway as a possible mechanism behind the anticancer as well as chemopreventive efficacy of [6]-gingerol against colon cancer.
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Affiliation(s)
- EK Radhakrishnan
- Division of Plant Molecular Biology, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Smitha V. Bava
- Division of Cancer Research, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Sai Shyam Narayanan
- Division of Cancer Research, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Lekshmi R. Nath
- Division of Cancer Research, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | | | - Eppurathu Vasudevan Soniya
- Division of Plant Molecular Biology, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
| | - Ruby John Anto
- Division of Cancer Research, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India
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Liu X, Cui X, Shan N, Li Y, Fang X, Ding M, Wang X. Downregulation of the H-2Kd gene by siRNA affects the cytotoxicity of murine LAK cells. Cancer Cell Int 2013; 13:112. [PMID: 24206544 PMCID: PMC3827616 DOI: 10.1186/1475-2867-13-112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 11/04/2013] [Indexed: 01/09/2023] Open
Abstract
To investigate the effect of the H-2Kd gene on the lymphocyte membrane, we constructed a small interfering RNA (siRNA) that targets the H-2Kd gene and compared the cytotoxicity of mouse lymphokine-activated killer (LAK) cells with different H-2Kd expression states. H-2Kd-targeting siRNA was transfected into spleen lymphocytes of BALB/C mice. Flow cytometry (FCM) was then performed to examine the expression of the H-2Kd gene in the transfected and control cells. Additionally, the cytotoxicity of the transfected cells toward the H22 and K562 cell lines was evaluated in vitro using the LDH release assay. H-2Kd-targeting siRNA significantly reduced the expression levels of the target protein, whereas pure transMessenger and non-silencing siRNA did not inhibit H-2Kd expression at the concentrations tested. The cytotoxicity of siRNA-treated LAK cells toward H22 and K562 cells was reduced significantly. The knockdown of H-2Kd gene expression by siRNA may be associated with LAK cell cytotoxicity toward neoplasm cell lines.
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Affiliation(s)
| | | | | | | | | | | | - Xin Wang
- Department of Hematology, Shandong Provincial Hospital Affiliated to Shandong University, 324 Jing Wu Rd, Jinan, Shandong 250021, China.
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HLA class II defects in Burkitt lymphoma: bryostatin-1-induced 17 kDa protein restores CD4+ T-cell recognition. Clin Dev Immunol 2011; 2011:780839. [PMID: 22162713 PMCID: PMC3227386 DOI: 10.1155/2011/780839] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 09/05/2011] [Indexed: 01/26/2023]
Abstract
While the defects in HLA class I-mediated Ag presentation by Burkitt lymphoma (BL) have been well documented, CD4+ T-cells are also poorly stimulated by HLA class II Ag presentation, and the reasons underlying this defect(s) have not yet been fully resolved. Here, we show that BL cells are deficient in their ability to optimally stimulate CD4+ T cells via the HLA class II pathway. The observed defect was not associated with low levels of BL-expressed costimulatory molecules, as addition of external co-stimulation failed to result in BL-mediated CD4+ T-cell activation. We further demonstrate that BL cells express the components of the class II pathway, and the defect was not caused by faulty Ag/class II interaction, because antigenic peptides bound with measurable affinity to BL-associated class II molecules. Treatment of BL with broystatin-1, a potent modulator of protein kinase C, led to significant improvement of functional class II Ag presentation in BL. The restoration of immune recognition appeared to be linked with an increased expression of a 17 kDa peptidylprolyl-like protein. These results demonstrate the presence of a specific defect in HLA class II-mediated Ag presentation in BL and reveal that treatment with bryostatin-1 could lead to enhanced immunogenicity.
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Enhancement of HLA class II-restricted CD4+ T cell recognition of human melanoma cells following treatment with bryostatin-1. Cell Immunol 2011; 271:392-400. [PMID: 21903207 DOI: 10.1016/j.cellimm.2011.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 08/11/2011] [Accepted: 08/12/2011] [Indexed: 12/31/2022]
Abstract
The majority of melanoma cells express detectable levels of HLA class II proteins, and an increased threshold of cell surface class II is crucial for the stimulation of CD4+ T cells. Bryostatin-1, a protein kinase C (PKC) activator, has been considered as a potent chemotherapeutic agent in a variety of in vitro tumor models. Little is known about the role of bryostatin-1 in HLA class II Ag presentation and immune activation in malignant tumors, especially in melanoma. In this study, we show that bryostatin-1 treatment enhances CD4+ T cell recognition of melanoma cells in the context of HLA class II molecules. We also show that bryostatin-1 treatment of melanoma cells increases class II protein levels by upregulating the class II transactivator (CIITA) gene. Flow cytometry and confocal microscopic analyses revealed that bryostatin-1 treatment upregulated the expression of costimulatory molecules (CD80 and CD86) in melanoma cells, which could prolong the interaction of immune cells and tumors. Bryostatin-1 also induced cellular differentiation in melanoma cells, and reduced tumorigenic factors such as pro-cathepsins and matrix-metalloproteinase-9. These data suggest that bryostatin-1 could be used as a chemo-immunotherapeutic agent for reducing tumorigenic potential of melanoma cells while enhancing CD4+ T cell recognition to prevent tumor recurrence.
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Ritsema T, Brodmann D, Diks SH, Bos CL, Nagaraj V, Pieterse CM, Boller T, Wiemken A, Peppelenbosch MP. Are small GTPases signal hubs in sugar-mediated induction of fructan biosynthesis? PLoS One 2009; 4:e6605. [PMID: 19672308 PMCID: PMC2720452 DOI: 10.1371/journal.pone.0006605] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Accepted: 06/20/2009] [Indexed: 11/19/2022] Open
Abstract
External sugar initiates biosynthesis of the reserve carbohydrate fructan, but the molecular processes mediating this response remain obscure. Previously it was shown that a phosphatase and a general kinase inhibitor hamper fructan accumulation. We use various phosphorylation inhibitors both in barley and in Arabidopsis and show that the expression of fructan biosynthetic genes is dependent on PP2A and different kinases such as Tyr-kinases and PI3-kinases. To further characterize the phosphorylation events involved, comprehensive analysis of kinase activities in the cell was performed using a PepChip, an array of >1000 kinase consensus substrate peptide substrates spotted on a chip. Comparison of kinase activities in sugar-stimulated and mock(sorbitol)-treated Arabidopsis demonstrates the altered phosphorylation of many consensus substrates and documents the differences in plant kinase activity upon sucrose feeding. The different phosphorylation profiles obtained are consistent with sugar-mediated alterations in Tyr phosphorylation, cell cycling, and phosphoinositide signaling, and indicate cytoskeletal rearrangements. The results lead us to infer a central role for small GTPases in sugar signaling.
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Affiliation(s)
- Tita Ritsema
- Botanisches Institut der Universität Basel, Zurich Basel Plant Science Center, Basel, Switzerland
- Plant-Microbe interactions, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands
| | - David Brodmann
- Botanisches Institut der Universität Basel, Zurich Basel Plant Science Center, Basel, Switzerland
| | - Sander H. Diks
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Carina L. Bos
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Vinay Nagaraj
- Botanisches Institut der Universität Basel, Zurich Basel Plant Science Center, Basel, Switzerland
| | - Corné M.J. Pieterse
- Plant-Microbe interactions, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands
| | - Thomas Boller
- Botanisches Institut der Universität Basel, Zurich Basel Plant Science Center, Basel, Switzerland
| | - Andres Wiemken
- Botanisches Institut der Universität Basel, Zurich Basel Plant Science Center, Basel, Switzerland
| | - Maikel P. Peppelenbosch
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- * E-mail:
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Chakraborty D, Basu JM, Sen P, Sundar S, Roy S. Human placental extract offers protection against experimental visceral leishmaniasis: a pilot study for a phase-I clinical trial. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2008; 102:21-38. [PMID: 18186975 DOI: 10.1179/136485908x252133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
An aqueous extract of human placenta (HPE) was found to offer protection against established experimental visceral leishmaniasis in BALB/c mice and hamsters, whether the Leishmania donovani strain involved was one that was sensitive or resistant to pentavalent antimony. Intraperitoneal administration of the extract, into mice or hamsters that had been infected 2 months previously, led to antileishmanial T-cell proliferation among splenic mononuclear cells, the generation of host-protective cytokines (interferon-gamma, tumour necrosis factor and interleukin-12) and the upregulation of the expression of inducible nitric oxide synthase (and subsequent NO generation) in splenocytes. Furthermore, splenic macrophages from the HPE-treated mice showed increased generation of reactive oxygen species and enhanced surface expression of antigens of major histocompatibility complex class II (MHCII), and the extract restored the otherwise-defective antigen-presenting ability of the macrophages. Thus, in mice and hamsters infected with L. donovani, HPE therapy can stimulate both arms of the host's immune system and favour the complete resolution of the leishmanial infection. Among five human cases of visceral leishmaniasis, 30 daily intramuscular injections of HPE, at doses much lower than those used in the experimental infections, also gave very promising results. Based on the results of this pilot study, a further evaluation of the efficacy of HPE therapy, which may offer a cost-effective way of improving the treatment of antimony-resistant cases of visceral leishmaniasis, is being undertaken.
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Affiliation(s)
- D Chakraborty
- Department of Immunology, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, India
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Abstract
The INK4a/ARF locus encodes two proteins whose expression limits cellular proliferation. Whilst the biochemical activities of the two proteins appear very different, they both converge on regulating the retinoblastoma and p53 tumour suppressor pathways. Neither protein is required for normal development, but lack of either predisposes to the development of malignancy. Both proteins have also been implicated in the establishment of senescence states in response to a variety of stresses, signalling imbalances and telomere shortening. The INK4a/Arf regulatory circuits appear to be partially redundant and show evidence of rapid evolution. Especially intriguing are the large number of biological differences documented between mice and man. We review here the brief history of INK4a/Arf and explore possible links with organismal aging and the evolution of longevity.
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Affiliation(s)
- Carol J Collins
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
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