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Li M, Chang J, Ren H, Song D, Guo J, Peng L, Zhou X, Zhao K, Lu S, Liu Z, Hu P. Downregulation of CCKBR Expression Inhibits the Proliferation of Gastric Cancer Cells, Revealing a Potential Target for Immunotoxin Therapy. Curr Cancer Drug Targets 2022; 22:257-268. [PMID: 34994328 DOI: 10.2174/1568009622666220106113616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/14/2021] [Accepted: 11/12/2021] [Indexed: 11/22/2022]
Abstract
Background Increased CCKBR expression density or frequency has been reported in many neoplasms. Objective We aimed to investigate whether CCKBR drives the growth of gastric cancer (GC) and its potential as a therapeutic target of immunotoxins. Methods A lentiviral interference system was used to generate CCKBR-knockdown gastric cancer cells. Cell Counting Kit-8 and clonogenic assays were used to evaluate cell proliferation. Wound-healing and cell invasion assays were performed to evaluate cell mobility. Cell cycle was analyzed by flow cytometry. Tumor growth in vivo was investigated using a heterologous tumor transplantation model in nude mice. In addition, we generated the immunotoxin FQ17P and evaluated the combining capacity and tumor cytotoxicity of FQ17P in vitro. Results Stable downregulation of CCKBR expression resulted in reduced proliferation, migration and invasion of BGC-823 and SGC-7901 cells. The impact of CCKBR on gastric cancer cells was further verified through CCKBR overexpression studies. Downregulation of CCKBR expression also inhibited the growth of gastric tumors in vivo. Furthermore, FQ17P killed CCKBR-overexpressing GC cells by specifically binding to CCKBR on the tumor cell surface. Conclusion The CCKBR protein drives the growth, migration, and invasion of gastric cancer cells, and it might be a promising target for immunotoxin therapy based on its aberrant expression, functional binding interactions with gastrin, and subsequent internalization.
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Affiliation(s)
- Meng Li
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Jiang Chang
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Honglin Ren
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Defeng Song
- China-Japan Union Hospital, Jilin University; Changchun 130062, China
| | - Jian Guo
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Lixiong Peng
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Xiaoshi Zhou
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Ke Zhao
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Shiying Lu
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Zengshan Liu
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
| | - Pan Hu
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Double-First Class Discipline of Human-Animal Medicine, Jilin University; Changchun 130062, China
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2
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Zeng Q, Ou L, Wang W, Guo DY. Gastrin, Cholecystokinin, Signaling, and Biological Activities in Cellular Processes. Front Endocrinol (Lausanne) 2020; 11:112. [PMID: 32210918 PMCID: PMC7067705 DOI: 10.3389/fendo.2020.00112] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 02/20/2020] [Indexed: 12/24/2022] Open
Abstract
The structurally-related peptides, gastrin and cholecystokinin (CCK), were originally discovered as humoral stimulants of gastric acid secretion and pancreatic enzyme release, respectively. With the aid of methodological advances in biochemistry, immunochemistry, and molecular biology in the past several decades, our concept of gastrin and CCK as simple gastrointestinal hormones has changed considerably. Extensive in vitro and in vivo studies have shown that gastrin and CCK play important roles in several cellular processes including maintenance of gastric mucosa and pancreatic islet integrity, neurogenesis, and neoplastic transformation. Indeed, gastrin and CCK, as well as their receptors, are expressed in a variety of tumor cell lines, animal models, and human samples, and might contribute to certain carcinogenesis. In this review, we will briefly introduce the gastrin and CCK system and highlight the effects of gastrin and CCK in the regulation of cell proliferation and apoptosis in both normal and abnormal conditions. The potential imaging and therapeutic use of these peptides and their derivatives are also summarized.
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Affiliation(s)
- Qiang Zeng
- Health Management Institute, People's Liberation Army General Hospital, Beijing, China
| | - Lei Ou
- Health Management Institute, People's Liberation Army General Hospital, Beijing, China
| | - Wei Wang
- Department of Clinical Laboratory, Xiamen Huli Guoyu Clinic, Co., Ltd., Xiamen, China
- *Correspondence: Wei Wang
| | - Dong-Yu Guo
- Department of Clinical Laboratory, Xiamen Huli Guoyu Clinic, Co., Ltd., Xiamen, China
- Dong-Yu Guo
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3
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Abstract
Gastric acid secretion (i) facilitates digestion of protein as well as absorption of micronutrients and certain medications, (ii) kills ingested microorganisms, including Helicobacter pylori, and (iii) prevents bacterial overgrowth and enteric infection. The principal regulators of acid secretion are the gastric peptides gastrin and somatostatin. Gastrin, the major hormonal stimulant for acid secretion, is synthesized in pyloric mucosal G cells as a 101-amino acid precursor (preprogastrin) that is processed to yield biologically active amidated gastrin-17 and gastrin-34. The C-terminal active site of gastrin (Trp-Met-Asp-Phe-NH2 ) binds to gastrin/CCK2 receptors on parietal and, more importantly, histamine-containing enterochromaffin-like (ECL) cells, located in oxyntic mucosa, to induce acid secretion. Histamine diffuses to the neighboring parietal cells where it binds to histamine H2 -receptors coupled to hydrochloric acid secretion. Gastrin is also a trophic hormone that maintains the integrity of gastric mucosa, induces proliferation of parietal and ECL cells, and is thought to play a role in carcinogenesis. Somatostatin, present in D cells of the gastric pyloric and oxyntic mucosa, is the main inhibitor of acid secretion, particularly during the interdigestive period. Somatostatin exerts a tonic paracrine restraint on gastrin secretion from G cells, histamine secretion from ECL cells, and acid secretion from parietal cells. Removal of this restraint, for example by activation of cholinergic neurons during ingestion of food, initiates and maximizes acid secretion. Knowledge regarding the structure and function of gastrin, somatostatin, and their respective receptors is providing novel avenues to better diagnose and manage acid-peptic disorders and certain cancers. Published 2020. Compr Physiol 10:197-228, 2020.
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Affiliation(s)
- Mitchell L Schubert
- Division of Gastroenterology, Department of Medicine, Virginia Commonwealth University Health System, Richmond, Virginia, USA.,Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia, USA
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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4
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Mjønes P, Nordrum IS, Sørdal Ø, Sagatun L, Fossmark R, Sandvik A, Waldum HL. Expression of the Cholecystokinin-B Receptor in Neoplastic Gastric Cells. Discov Oncol 2017; 9:40-54. [PMID: 28980157 PMCID: PMC5775387 DOI: 10.1007/s12672-017-0311-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/25/2017] [Indexed: 12/13/2022] Open
Abstract
Gastric cancer is an important disease due to its high mortality. Despite the decline in frequency, most cases are discovered late in its course, and most of the cancer patients die within a few years of diagnosis. In addition to Helicobacter pylori gastritis, gastrin is considered an important factor in the development of this disease, and thus, cholecystokinin-B receptor (CCKBR) becomes of interest. The aim of our study was to explore whether CCKBR is expressed in stomach cancers. Thirty-seven tumors from 19 men and 18 women diagnosed with either adenocarcinoma or neuroendocrine neoplasm (NENs) were included in this study. The tumors were classified into 29 adenocarcinomas and eight NENs. Immunohistochemistry with antibodies against chromogranin A (CgA), synaptophysin and CCKBR, and in situ hybridization with probes against CgA, CCKBR and histidine decarboxylase were used to further explore these tumors. Thirty-three (89%) of the tumors expressed CCKBR protein, whereas only 20 (54%) of all tumors expressed CCKBR mRNA. Of the 20 tumors expressing CCKBR mRNA, eight were NENs and 12 were adenocarcinoma. The highest amount of CCKBR was expressed in NEN. Interestingly, a high degree of co-expression of CCKBR and CgA was observed when the two markers were examined together with in situ hybridization. In conclusion, we found that all eight NENs expressed CCKBR and neuroendocrine markers in a majority of tumor cells. The same markers were also expressed in a proportion of adenocarcinomas supporting the view that gastrin is important in the development of gastric cancer.
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Affiliation(s)
- Patricia Mjønes
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway. .,Department of Pathology, St Olav's Hospital-Trondheim University Hospital, Trondheim, Norway. .,Department of Laboratory Medicine, Children's and Woman's Health, NTNU, Trondheim, Norway.
| | - Ivar S Nordrum
- Department of Pathology, St Olav's Hospital-Trondheim University Hospital, Trondheim, Norway.,Department of Laboratory Medicine, Children's and Woman's Health, NTNU, Trondheim, Norway
| | - Øystein Sørdal
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Gastroenterology and Hepatology, St Olav's Hospital-Trondheim University Hospital, Trondheim, Norway
| | - Liv Sagatun
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Gastroenterology and Hepatology, St Olav's Hospital-Trondheim University Hospital, Trondheim, Norway
| | - Reidar Fossmark
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Gastroenterology and Hepatology, St Olav's Hospital-Trondheim University Hospital, Trondheim, Norway
| | - Arne Sandvik
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Gastroenterology and Hepatology, St Olav's Hospital-Trondheim University Hospital, Trondheim, Norway
| | - Helge L Waldum
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Gastroenterology and Hepatology, St Olav's Hospital-Trondheim University Hospital, Trondheim, Norway
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5
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Chang JK, Ni Y, Han L, Sinnett-Smith J, Jacamo R, Rey O, Young SH, Rozengurt E. Protein kinase D1 (PKD1) phosphorylation on Ser 203 by type I p21-activated kinase (PAK) regulates PKD1 localization. J Biol Chem 2017; 292:9523-9539. [PMID: 28408623 DOI: 10.1074/jbc.m116.771394] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 04/11/2017] [Indexed: 01/07/2023] Open
Abstract
Although PKC-mediated phosphorylation of protein kinase D1 (PKD1) has been extensively characterized, little is known about PKD1 regulation by other upstream kinases. Here we report that stimulation of epithelial or fibroblastic cells with G protein-coupled receptor agonists, including angiotensin II or bombesin, induced rapid and persistent PKD1 phosphorylation at Ser203, a highly conserved residue located within the PKD1 N-terminal domain. Exposure to PKD or PKC family inhibitors did not prevent PKD1 phosphorylation at Ser203, indicating that it is not mediated by autophosphorylation. In contrast, several lines of evidence indicated that the phosphorylation of PKD1 at Ser203 is mediated by kinases of the class I PAK subfamily, specifically 1) exposing cells to four structurally unrelated PAK inhibitors (PF-3758309, FRAX486, FRAX597, and IPA-3) that act via different mechanisms abrogated PKD1 phosphorylation at Ser203, 2) siRNA-mediated knockdown of PAK1 and PAK2 in IEC-18 and Swiss 3T3 cells blunted PKD1 phosphorylation at Ser203, 3) phosphorylation of Ser203 markedly increased in vitro when recombinant PKD1 was incubated with either PAK1 or PAK2 in the presence of ATP. PAK inhibitors did not interfere with G protein-coupled receptor activation-induced rapid translocation of PKD1 to the plasma membrane but strikingly prevented the dissociation of PKD1 from the plasma membrane and blunted the phosphorylation of nuclear targets, including class IIa histone deacetylases. We conclude that PAK-mediated phosphorylation of PKD1 at Ser203 triggers its membrane dissociation and subsequent entry into the nucleus, thereby regulating the phosphorylation of PKD1 nuclear targets, including class IIa histone deacetylases.
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Affiliation(s)
- Jen-Kuan Chang
- From the Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine
| | - Yang Ni
- From the Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine
| | - Liang Han
- From the Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine
| | - James Sinnett-Smith
- From the Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine.,CURE: Digestive Diseases Research Center, and.,Veterans Affairs Greater Los Angeles Health Care System and
| | - Rodrigo Jacamo
- the Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030-4017, and
| | - Osvaldo Rey
- the Institute of Immunology, Genetics, and Metabolism, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Universidad de Buenos Aires, Buenos Aires C1120AAR, Argentina
| | - Steven H Young
- From the Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine.,CURE: Digestive Diseases Research Center, and.,Veterans Affairs Greater Los Angeles Health Care System and
| | - Enrique Rozengurt
- From the Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, .,CURE: Digestive Diseases Research Center, and.,Veterans Affairs Greater Los Angeles Health Care System and.,the Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095-1786
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6
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Fino KK, Matters GL, McGovern CO, Gilius EL, Smith JP. Downregulation of the CCK-B receptor in pancreatic cancer cells blocks proliferation and promotes apoptosis. Am J Physiol Gastrointest Liver Physiol 2012; 302:G1244-52. [PMID: 22442157 PMCID: PMC3378167 DOI: 10.1152/ajpgi.00460.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Gastrin stimulates the growth of pancreatic cancer cells through the activation of the cholecystokinin-B receptor (CCK-BR), which has been found to be overexpressed in pancreatic cancer. In this study, we proposed that the CCK-BR drives growth of pancreatic cancer; hence, interruption of CCK-BR activity could potentially be an ideal target for cancer therapeutics. The effect of CCK-BR downregulation in the human pancreatic adenocarcinoma cells was examined by utilizing specific CCK-BR-targeted RNA interference reagents. The CCK-BR receptor expression was both transiently and stably downregulated by transfection with selective CCK-BR small-interfering RNA or short-hairpin RNA, respectively, and the effects on cell growth and apoptosis were assessed. CCK-BR downregulation resulted in reduced cancer cell proliferation, decreased DNA synthesis, and cell cycle arrest as demonstrated by an inhibition of G(1) to S phase progression. Furthermore, CCK-BR downregulation increased caspase-3 activity, TUNEL-positive cells, and decreased X-linked inhibitor of apoptosis protein expression, suggesting apoptotic activity. Pancreatic cancer cell mobility was decreased when the CCK-BR was downregulated, as assessed by a migration assay. These results show the importance of the CCK-BR in regulation of growth and apoptosis in pancreatic cancer. Strategies to decrease the CCK-BR expression and activity may be beneficial for the development of new methods to improve the treatment for patients with pancreatic cancer.
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Affiliation(s)
| | - Gail L. Matters
- Departments of 1Medicine and ,2Biochemistry and Molecular Biology, College of Medicine, Pennsylvania State University, Hershey, Pennsylvania
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7
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Differential PKC-dependent and -independent PKD activation by G protein α subunits of the Gq family: selective stimulation of PKD Ser⁷⁴⁸ autophosphorylation by Gαq. Cell Signal 2011; 24:914-21. [PMID: 22227248 DOI: 10.1016/j.cellsig.2011.12.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 12/06/2011] [Accepted: 12/19/2011] [Indexed: 11/21/2022]
Abstract
Protein kinase D (PKD) is activated within cells by stimulation of multiple G protein coupled receptors (GPCR). Earlier studies demonstrated a role for PKC to mediate rapid activation loop phosphorylation-dependent PKD activation. Subsequently, a novel PKC-independent pathway in response to Gαq-coupled GPCR stimulation was identified. Here, we examined further the specificity and PKC-dependence of PKD activation using COS-7 cells cotransfected with different Gq-family Gα and stimulated with aluminum fluoride (AlF4⁻). PKD activation was measured by kinase assays, and Western blot analysis of activation loop sites Ser⁷⁴⁴, a prominent and rapid PKC transphosphorylation site, and Ser⁷⁴⁸, a site autophosphorylated in the absence of PKC signaling. Treatment with AlF4⁻ potently induced PKD activation and Ser⁷⁴⁴ and Ser⁷⁴⁸ phosphorylation, in the presence of cotransfected Gαq, Gα11, Gα14 or Gα15. These treatments achieved PKD activation loop phosphorylation similar to the maximal levels obtained by stimulation with the phorbol ester, PDBu. Preincubation with the PKC inhibitor GF1 potently blocked Gα11-, Gα14-, and Gα15-mediated enhancement of Ser⁷⁴⁸ phosphorylation induced by AlF4⁻, and largely abolished Ser⁷⁴⁴ phosphorylation. In contrast, Ser⁷⁴⁸ phosphorylation was almost completely intact, and Ser⁷⁴⁴ phosphorylation was significantly activated in cells cotransfected with Gαq. Importantly, the differential Ser⁷⁴⁸ phosphorylation was also promoted by treatment of Swiss 3T3 cells with Pasteurella multocida toxin, a selective activator of Gαq but not Gα11. Taken together, our results suggest that Gαq, but not the closely related Gα11, promotes PKD activation in response to GPCR ligands in a unique manner leading to PKD autophosphorylation at Ser⁷⁴⁸.
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8
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Cayrol C, Bertrand C, Kowalski-Chauvel A, Daulhac L, Cohen-Jonathan-Moyal E, Ferrand A, Seva C. α V integrin: A new gastrin target in human pancreatic cancer cells. World J Gastroenterol 2011; 17:4488-95. [PMID: 22110279 PMCID: PMC3218139 DOI: 10.3748/wjg.v17.i40.4488] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/12/2011] [Accepted: 02/19/2011] [Indexed: 02/06/2023] Open
Abstract
AIM: To analyse αV integrin expression induced by gastrin in pancreatic cancer models.
METHODS: αV integrin mRNA expression in human pancreatic cancer cells was analysed using a “cancer genes” array and confirmed by real-time reverse transcription-polymerase chain reaction (PCR). Western blotting and semi-quantitative immunohistochemistry were used to examine protein levels in human pancreatic cancer cell lines and pancreatic tissues, respectively. The role of αV integrin on gastrin-induced cell adhesion was examined using blocking anti-αV integrin monoclonal antibodies. Adherent cells were quantified by staining with crystal violet.
RESULTS: Using a “cancer genes” array we identified αV integrin as a new gastrin target gene in human pancreatic cancer cells. A quantitative real-time PCR approach was used to confirm αV integrin gene expression. We also demonstrate that Src family kinases and the PI 3-kinase, two signalling pathways specifically activated by the CCK-2 receptor (CCK2R), are involved in gastrin-mediated αV integrin expression. In contrast, inhibition of the ERK pathway was without any effect on αV integrin expression induced by gastrin. Our results also show that gastrin modulates cell adhesion viaαV integrins. Indeed, in vitro adhesion assays performed on fibronectin show that gastrin significantly increases adhesion of pancreatic cancer cells. The use of blocking anti-αV integrin monoclonal antibodies completely reversed the increase in cell-substrate adhesion induced by gastrin. In addition, we showed in vivo that the targeted CCK2R expression in the pancreas of Elas-CCK2 mice, leads to the overexpression of αV integrin. This process may contribute to pancreatic tumour development observed in these transgenic animals.
CONCLUSION: αV integrin is a new gastrin target in pancreatic cancer models and contributes to gastrin effects on cell adhesion.
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Kleger A, Loebnitz C, Pusapati GV, Armacki M, Müller M, Tümpel S, Illing A, Hartmann D, Brunner C, Liebau S, Rudolph KL, Adler G, Seufferlein T. Protein kinase D2 is an essential regulator of murine myoblast differentiation. PLoS One 2011; 6:e14599. [PMID: 21298052 PMCID: PMC3029294 DOI: 10.1371/journal.pone.0014599] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 12/18/2010] [Indexed: 11/27/2022] Open
Abstract
Muscle differentiation is a highly conserved process that occurs through the activation of quiescent satellite cells whose progeny proliferate, differentiate, and fuse to generate new myofibers. A defined pattern of myogenic transcription factors is orchestrated during this process and is regulated via distinct signaling cascades involving various intracellular signaling pathways, including members of the protein kinase C (PKC) family. The protein kinase D (PKD) isoenzymes PKD1, -2, and -3, are prominent downstream targets of PKCs and phospholipase D in various biological systems including mouse and could hence play a role in muscle differentiation. In the present study, we used a mouse myoblast cell line (C2C12) as an in vitro model to investigate the role of PKDs, in particular PKD2, in muscle stem cell differentiation. We show that C2C12 cells express all PKD isoforms with PKD2 being highly expressed. Furthermore, we demonstrate that PKD2 is specifically phosphorylated/activated during the initiation of mouse myoblast differentiation. Selective inhibition of PKCs or PKDs by pharmacological inhibitors blocked myotube formation. Depletion of PKD2 by shRNAs resulted in a marked inhibition of myoblast cell fusion. PKD2-depleted cells exhibit impaired regulation of muscle development-associated genes while the proliferative capacity remains unaltered. Vice versa forced expression of PKD2 increases myoblast differentiation. These findings were confirmed in primary mouse satellite cells where myotube fusion was also decreased upon inhibition of PKDs. Active PKD2 induced transcriptional activation of myocyte enhancer factor 2D and repression of Pax3 transcriptional activity. In conclusion, we identify PKDs, in particular PKD2, as a major mediator of muscle cell differentiation in vitro and thereby as a potential novel target for the modulation of muscle regeneration.
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Affiliation(s)
- Alexander Kleger
- Department of Internal Medicine I, University of Ulm, Ulm, Germany
- Institute of Molecular Medicine and Max-Planck-Research Department on Stem Cell Aging, University of Ulm, Ulm, Germany
| | | | | | - Milena Armacki
- Department of Internal Medicine I, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Martin Müller
- Department of Internal Medicine I, University of Ulm, Ulm, Germany
| | - Stefan Tümpel
- Institute of Molecular Medicine and Max-Planck-Research Department on Stem Cell Aging, University of Ulm, Ulm, Germany
| | - Anett Illing
- Institute of Molecular Medicine and Max-Planck-Research Department on Stem Cell Aging, University of Ulm, Ulm, Germany
| | - Daniel Hartmann
- Institute of Molecular Medicine and Max-Planck-Research Department on Stem Cell Aging, University of Ulm, Ulm, Germany
- Department of Surgery, Technical University Munich, Munich, Germany
| | - Cornelia Brunner
- Institute of Physiological Chemistry, University of Ulm, Ulm, Germany
| | - Stefan Liebau
- Institute of Anatomy and Cell Biology, University of Ulm, Ulm, Germany
| | - Karl L. Rudolph
- Institute of Molecular Medicine and Max-Planck-Research Department on Stem Cell Aging, University of Ulm, Ulm, Germany
| | - Guido Adler
- Department of Internal Medicine I, University of Ulm, Ulm, Germany
| | - Thomas Seufferlein
- Department of Internal Medicine I, Martin Luther University Halle-Wittenberg, Halle, Germany
- * E-mail:
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10
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Sinnett-Smith J, Rozengurt N, Kui R, Huang C, Rozengurt E. Protein kinase D1 mediates stimulation of DNA synthesis and proliferation in intestinal epithelial IEC-18 cells and in mouse intestinal crypts. J Biol Chem 2010; 286:511-20. [PMID: 21051537 DOI: 10.1074/jbc.m110.167528] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We examined whether protein kinase D1 (PKD1), the founding member of a new protein kinase family, plays a critical role in intestinal epithelial cell proliferation. Our results demonstrate that PKD1 activation is sustained, whereas that of PKD2 is transient in intestinal epithelial IEC-18 stimulated with the G(q)-coupled receptor agonists angiotensin II or vasopressin. PKD1 gene silencing utilizing small interfering RNAs dramatically reduced DNA synthesis and cell proliferation in IEC-18 cells stimulated with G(q)-coupled receptor agonists. To clarify the role of PKD1 in intestinal epithelial cell proliferation in vivo, we generated transgenic mice that express elevated PKD1 protein in the intestinal epithelium. Transgenic PKD1 exhibited constitutive catalytic activity and phosphorylation at the activation loop residues Ser(744) and Ser(748) and on the autophosphorylation site, Ser(916). To examine whether PKD1 expression stimulates intestinal cell proliferation, we determined the rate of crypt cell DNA synthesis by detection of 5-bromo-2-deoxyuridine incorporated into the nuclei of crypt cells of the ileum. Our results demonstrate a significant increase (p < 0.005) in DNA-synthesizing cells in the crypts of two independent lines of PKD1 transgenic mice as compared with non-transgenic littermates. Morphometric analysis showed a significant increase in the length and in the total number of cells per crypt in the transgenic PKD1 mice as compared with the non-transgenic littermates (p < 0.01). Thus, transgenic PKD1 signaling increases the number of cells per crypt by stimulating the rate of crypt cell proliferation. Collectively, our results indicate that PKD1 plays a role in promoting cell proliferation in intestinal epithelial cells both in vitro and in vivo.
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Affiliation(s)
- James Sinnett-Smith
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
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11
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Sinnett-Smith J, Jacamo R, Kui R, Wang YM, Young SH, Rey O, Waldron RT, Rozengurt E. Protein kinase D mediates mitogenic signaling by Gq-coupled receptors through protein kinase C-independent regulation of activation loop Ser744 and Ser748 phosphorylation. J Biol Chem 2009; 284:13434-13445. [PMID: 19289471 DOI: 10.1074/jbc.m806554200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Rapid protein kinase D (PKD) activation and phosphorylation via protein kinase C (PKC) have been extensively documented in many cell types cells stimulated by multiple stimuli. In contrast, little is known about the role and mechanism(s) of a recently identified sustained phase of PKD activation in response to G protein-coupled receptor agonists. To elucidate the role of biphasic PKD activation, we used Swiss 3T3 cells because PKD expression in these cells potently enhanced duration of ERK activation and DNA synthesis in response to G(q)-coupled receptor agonists. Cell treatment with the preferential PKC inhibitors GF109203X or Gö6983 profoundly inhibited PKD activation induced by bombesin stimulation for <15 min but did not prevent PKD catalytic activation induced by bombesin stimulation for longer times (>60 min). The existence of sequential PKC-dependent and PKC-independent PKD activation was demonstrated in 3T3 cells stimulated with various concentrations of bombesin (0.3-10 nm) or with vasopressin, a different G(q)-coupled receptor agonist. To gain insight into the mechanisms involved, we determined the phosphorylation state of the activation loop residues Ser(744) and Ser(748). Transphosphorylation targeted Ser(744), whereas autophosphorylation was the predominant mechanism for Ser(748) in cells stimulated with G(q)-coupled receptor agonists. We next determined which phase of PKD activation is responsible for promoting enhanced ERK activation and DNA synthesis in response to G(q)-coupled receptor agonists. We show, for the first time, that the PKC-independent phase of PKD activation mediates prolonged ERK signaling and progression to DNA synthesis in response to bombesin or vasopressin through a pathway that requires epidermal growth factor receptor-tyrosine kinase activity. Thus, our results identify a novel mechanism of G(q)-coupled receptor-induced mitogenesis mediated by sustained PKD activation through a PKC-independent pathway.
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Affiliation(s)
- James Sinnett-Smith
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Rodrigo Jacamo
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Robert Kui
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - YunZu M Wang
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Steven H Young
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Osvaldo Rey
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Richard T Waldron
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Enrique Rozengurt
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095.
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12
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Jacamo R, Sinnett-Smith J, Rey O, Waldron RT, Rozengurt E. Sequential protein kinase C (PKC)-dependent and PKC-independent protein kinase D catalytic activation via Gq-coupled receptors: differential regulation of activation loop Ser(744) and Ser(748) phosphorylation. J Biol Chem 2008; 283:12877-87. [PMID: 18337243 DOI: 10.1074/jbc.m800442200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase D (PKD) is a serine/threonine protein kinase rapidly activated by G protein-coupled receptor (GPCR) agonists via a protein kinase C (PKC)-dependent pathway. Recently, PKD has been implicated in the regulation of long term cellular activities, but little is known about the mechanism(s) of sustained PKD activation. Here, we show that cell treatment with the preferential PKC inhibitors GF 109203X or Gö 6983 blocked rapid (1-5-min) PKD activation induced by bombesin stimulation, but this inhibition was greatly diminished at later times of bombesin stimulation (e.g. 45 min). These results imply that GPCR-induced PKD activation is mediated by early PKC-dependent and late PKC-independent mechanisms. Western blot analysis with site-specific antibodies that detect the phosphorylated state of the activation loop residues Ser(744) and Ser(748) revealed striking PKC-independent phosphorylation of Ser(748) as well as Ser(744) phosphorylation that remained predominantly but not completely PKC-dependent at later times of bombesin or vasopressin stimulation (20-90 min). To determine the mechanisms involved, we examined activation loop phosphorylation in a set of PKD mutants, including kinase-deficient, constitutively activated, and PKD forms in which the activation loop residues were substituted for alanine. Our results show that PKC-dependent phosphorylation of the activation loop Ser(744) and Ser(748) is the primary mechanism involved in early phase PKD activation, whereas PKD autophosphorylation on Ser(748) is a major mechanism contributing to the late phase of PKD activation occurring in cells stimulated by GPCR agonists. The present studies identify a novel mechanism induced by GPCR activation that leads to late, PKC-independent PKD activation.
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Affiliation(s)
- Rodrigo Jacamo
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, USA
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13
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Abstract
G protein-coupled receptor (GPCR) agonists, including neurotransmitters, hormones, chemokines, and bioactive lipids, act as potent cellular growth factors and have been implicated in a variety of normal and abnormal processes, including development, inflammation, and malignant transformation. Typically, the binding of an agonistic ligand to its cognate GPCR triggers the activation of multiple signal transduction pathways that act in a synergistic and combinatorial fashion to relay the mitogenic signal to the nucleus and promote cell proliferation. A rapid increase in the activity of phospholipases C, D, and A2 leading to the synthesis of lipid-derived second messengers, Ca2+ fluxes and subsequent activation of protein phosphorylation cascades, including PKC/PKD, Raf/MEK/ERK, and Akt/mTOR/p70S6K is an important early response to mitogenic GPCR agonists. The EGF receptor (EGFR) tyrosine kinase has emerged as a transducer in the signaling by GPCRs, a process termed transactivation. GPCR signal transduction also induces striking morphological changes and rapid tyrosine phosphorylation of multiple cellular proteins, including the non-receptor tyrosine kinases Src, focal adhesion kinase (FAK), and the adaptor proteins CAS and paxillin. The pathways stimulated by GPCRs are extensively interconnected by synergistic and antagonistic crosstalks that play a critical role in signal transmission, integration, and dissemination. The purpose of this article is to review recent advances in defining the pathways that play a role in transducing mitogenic responses induced by GPCR agonists.
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Affiliation(s)
- Enrique Rozengurt
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095-1786, USA.
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14
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Steigedal TS, Bruland T, Misund K, Thommesen L, Laegreid A. Inducible cAMP early repressor suppresses gastrin-mediated activation of cyclin D1 and c-fos gene expression. Am J Physiol Gastrointest Liver Physiol 2007; 292:G1062-9. [PMID: 17185632 DOI: 10.1152/ajpgi.00287.2006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The gastric hormone gastrin and its precursors promote proliferation in several gastrointestinal cell types. Here we show that gastrin induces transcription of cell cycle gene cyclin D1 and protooncogene c-fos in the neuroendocrine pancreatic cell line AR42J and that this gastrin response is inhibited by endogenous inducible cAMP early repressor (ICER). The transcriptional repressor ICER is known to downregulate both its own expression and the expression of other genes containing cAMP-responsive elements (CREs). Using siRNA, we also show that CRE promoter elements are the targets of endogenous ICER in AR42J cells as well as in the neuroendocrine cell line RIN5F. Our results suggest that ICER plays an important role in molecular mechanisms governing gastrin-mediated growth by modulating gastrin's transcriptional activation of growth-related genes. Our finding that ICER modulates pituitary adenylate cyclase-activating polypeptide-activated gene expression also indicates a regulatory effect of ICER in the responses of neuroendocrine cells to peptides other than gastrin.
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Affiliation(s)
- Tonje S Steigedal
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, N-7489 Trondheim, Norway
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15
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Berna MJ, Hoffmann KM, Tapia JA, Thill M, Pace A, Mantey SA, Jensen RT. CCK causes PKD1 activation in pancreatic acini by signaling through PKC-delta and PKC-independent pathways. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1773:483-501. [PMID: 17306383 PMCID: PMC1924924 DOI: 10.1016/j.bbamcr.2006.12.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2006] [Revised: 12/02/2006] [Accepted: 12/18/2006] [Indexed: 12/25/2022]
Abstract
Protein kinase D1 (PKD1) is involved in cellular processes including protein secretion, proliferation and apoptosis. Studies suggest PKD1 is activated by various stimulants including gastrointestinal (GI) hormones/neurotransmitters and growth factors in a protein kinase C (PKC)-dependent pathway. However, little is known about the mechanisms of PKD1 activation in physiologic GI tissues. We explored PKD1 activation by GI hormones/neurotransmitters and growth factors and the mediators involved in rat pancreatic acini. Only hormones/neurotransmitters activating phospholipase C caused PKD1 phosphorylation (S916, S744/748). CCK activated PKD1 and caused a time- and dose-dependent increase in serine phosphorylation by activation of high- and low-affinity CCK(A) receptor states. Inhibition of CCK-stimulated increases in phospholipase C, PKC activity or intracellular calcium decreased PKD1 S916 phosphorylation by 56%, 62% and 96%, respectively. PKC inhibitors GF109203X/Go6976/Go6983/PKC-zeta pseudosubstrate caused a 62/43/49/0% inhibition of PKD1 S916 phosphorylation and an 87/13/82/0% inhibition of PKD1 S744/748 phosphorylation. Expression of dominant negative PKC-delta, but not PKC-epsilon, or treatment with PKC-delta translocation inhibitor caused marked inhibition of PKD phosphorylation. Inhibition of Src/PI3K/MAPK/tyrosine phosphorylation had no effect. In unstimulated cells, PKD1 was mostly located in the cytoplasm. CCK stimulated translocation of total and phosphorylated PKD1 to the membrane. These results demonstrate that CCK(A) receptor activation leads to PKD activation by signaling through PKC-dependent and PKC-independent pathways.
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Affiliation(s)
- Marc J. Berna
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, Maryland, 20892-1804, USA
| | - K. Martin Hoffmann
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, Maryland, 20892-1804, USA
| | - Jose A. Tapia
- Departamento de Fisiología, Universidad de Extremadura, Cáceres, 10071, Spain
| | - Michelle Thill
- National Eye Institute, NIH, Bethesda, Maryland, 20892-1804, USA
| | - Andrea Pace
- Medizinische Klinik I, Universitätsklinikum Hamburg-Eppendorf, 20246 Hamburg, Germany
| | | | - Robert T. Jensen
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, Maryland, 20892-1804, USA
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16
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Abstract
Cholecystokinin and gastrin receptors (CCK1R and CCK2R) are G protein-coupled receptors that have been the subject of intensive research in the last 10 years with corresponding advances in the understanding of their functioning and physiology. In this review, we first describe general properties of the receptors, such as the different signaling pathways used to exert short- and long-term effects and the structural data that explain their binding properties, activation, and regulation. We then focus on peripheral cholecystokinin receptors by describing their tissue distribution and physiological actions. Finally, pathophysiological peripheral actions of cholecystokinin receptors and their relevance in clinical disorders are reviewed.
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Affiliation(s)
- Marlène Dufresne
- Institut National de la Santé et de la Recherche Médicale U. 531, Institut Louis Bugnard, Centre Hospitalier Universitaire Rangueil, France
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17
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Jiang X, Jacamo R, Zhukova E, Sinnett-Smith J, Rozengurt E. RNA interference reveals a differential role of FAK and Pyk2 in cell migration, leading edge formation and increase in focal adhesions induced by LPA in intestinal epithelial cells. J Cell Physiol 2006; 207:816-28. [PMID: 16508947 DOI: 10.1002/jcp.20629] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the gastrointestinal mucosa, cell migration plays a crucial role in the organization and maintenance of tissue integrity but the mechanisms involved remain incompletely understood. Here, we used small-interfering RNA (siRNA)-mediated depletion of focal adhesion kinase (FAK) protein to determine the role of FAK in wound-induced migration and cytoskeletal organization in the non-transformed intestinal epithelial cells IEC-6 and IEC-18 stimulated with the G protein-coupled receptors (GPCR) agonist lysophosphatidic acid (LPA). Treatment of these cells with FAK siRNA substantially reduced FAK expression, but did not affect the expression of proline-rich tyrosine kinase 2 (Pyk2). Knockdown of FAK protein significantly inhibited LPA-induced migration of both IEC-18 and IEC-6 cells. LPA induced reorganization of actin and microtubule cytoskeleton in the leading edge was largely inhibited in FAK siRNA-transfected IEC-18 cells. Interestingly, in contrast to the FAK-/- cells, which exhibit an increased number of prominent focal adhesions when plated on fibronectin, FAK knockdown IEC-18 cells exhibited dramatically decreased number of focal adhesions in response to both LPA and fibronectin as compared with the control cells. We also used siRNAs to knockdown Pyk2 expression without reducing FAK expression. Depletion of Pyk2 did not prevent LPA-induced migration or cytoskeletal reorganization in IEC-18 cells. In conclusion, our study shows that FAK plays a critical role in LPA-induced migration, cytoskeletal reorganization, and assembly of focal adhesions in intestinal epithelial cells whereas depletion of Pyk2 did not interfere with any of these responses elicited by LPA.
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Affiliation(s)
- Xiaohua Jiang
- Department of Medicine, Division of Digestive Diseases, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095-178622, USA
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18
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Cayrol C, Clerc P, Bertrand C, Gigoux V, Portolan G, Fourmy D, Dufresne M, Seva C. Cholecystokinin-2 receptor modulates cell adhesion through beta 1-integrin in human pancreatic cancer cells. Oncogene 2006; 25:4421-8. [PMID: 16547500 DOI: 10.1038/sj.onc.1209484] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Several lines of evidence suggest that gastrin and the CCK-2 receptor (CCK2R) could contribute to pancreatic carcinogenesis by modulating processes such as proliferation, cell adhesion or migration. In the current study, we used a 'cancer gene array' and identified beta1-integrin subunit as a new gastrin-regulated gene in human pancreatic cancer cells. We also demonstrated that Src family kinases and the phosphatidylinositol-3-kinase (PI-3-kinase) pathway play a crucial role in the expression of beta1-integrin induced by gastrin. Our results also showed that gastrin modulates cell-substrate adhesion via beta1-integrin. Indeed, using blocking anti-beta1-integrin monoclonal antibodies, we completely reversed the increase in cell-substrate adhesion induced by gastrin. In addition, we observed that in response to gastrin, beta1-integrin is tyrosine phosphorylated by Src family kinases and associates with paxillin, a scaffold protein involved in focal adhesion and integrin signalling. This mechanism might be involved in gastrin-induced cell adhesion. Moreover, we showed in vivo that targeted CCK2R expression in the pancreas of Elas-CCK2 mice leads to the overexpression of beta1-integrin. This process may contribute to pancreatic tumour development observed in these transgenic animals.
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Affiliation(s)
- C Cayrol
- INSERM U 531, IFR 31, Institut Louis Bugnard, Toulouse, France
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19
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Affiliation(s)
- Enrique Rozengurt
- Department of Medicine, UCLA-CURE Digestive Diseases Research Center and Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA.
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20
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Rey O, Reeve JR, Zhukova E, Sinnett-Smith J, Rozengurt E. G protein-coupled receptor-mediated phosphorylation of the activation loop of protein kinase D: dependence on plasma membrane translocation and protein kinase Cepsilon. J Biol Chem 2004; 279:34361-72. [PMID: 15190080 DOI: 10.1074/jbc.m403265200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase D (PKD) is a serine/threonine protein kinase activated by G protein-coupled receptor (GPCR) agonists through an incompletely characterized mechanism that includes its reversible plasma membrane translocation and activation loop phosphorylation via a protein kinase C (PKC)-dependent pathway. To gain a better understanding of the mechanism regulating the activation of PKD in response to GPCR stimulation, we investigated the role of its rapid plasma membrane translocation on its activation loop phosphorylation and identified the endogenous PKC isozyme that mediates that event in vivo. We had found that the activation loop of a PKD mutant, with reduced affinity for diacylglycerol and phorbol esters, was only phosphorylated upon its plasma membrane association. We also found that the activation loop phosphorylation and rapid plasma membrane dissociation of PKD were inhibited either by preventing the plasma membrane translocation of PKCepsilon, through abolition of its interaction with receptor for activated C kinase, or by suppressing the expression of PKCepsilon via specific small interfering RNAs. Thus, this study demonstrates that the plasma membrane translocation of PKD, in response to GPCR stimulation, is necessary for the PKCepsilon-mediated phosphorylation of the activation loop of PKD and that this event requires the translocation of both kinases to the plasma membrane. Based on these and previous results, we propose a model of GPCR-mediated PKD regulation that integrates its changes in distribution, catalytic activity, and multisite phosphorylation.
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Affiliation(s)
- Osvaldo Rey
- Department of Medicine, UCLA-CURE Digestive Diseases Research Center and Molecular Biology Institute, David Geffen School of Medicine, University of California-Los Angeles, CA 90095, USA
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21
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Pradeep A, Sharma C, Sathyanarayana P, Albanese C, Fleming JV, Wang TC, Wolfe MM, Baker KM, Pestell RG, Rana B. Gastrin-mediated activation of cyclin D1 transcription involves beta-catenin and CREB pathways in gastric cancer cells. Oncogene 2004; 23:3689-99. [PMID: 15116100 DOI: 10.1038/sj.onc.1207454] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Gastrin and its precursors promote proliferation in different gastrointestinal cells. Since mature, amidated gastrin (G-17) can induce cyclin D1, we determined whether G-17-mediated induction of cyclin D1 transcription involved Wnt signaling and CRE-binding protein (CREB) pathways. Our studies indicate that G-17 induces protein, mRNA expression and transcription of the G(1)-specific marker cyclin D1, in the gastric adenocarcinoma cell line AGSE (expressing the gastrin/cholecystokinin B receptor). This was associated with an increase in steady-state levels of total and nonphospho beta-catenin and its nuclear translocation, indicating the activation of the Wnt-signaling pathway. In addition, G-17-mediated increase in cyclin D1 transcription was significantly attenuated by axin or dominant-negative (dn) T-cell factor 4(TCF4), suggesting crosstalk of G-17 with the Wnt-signaling pathway. Mutational analysis indicated that this effect was mediated through the cyclic AMP response element (CRE) (predominantly) and the TCF sites in the cyclin D1 promoter, which was also inhibited by dnCREB. Furthermore, G-17 stimulation resulted in increased CRE-responsive reporter activity and CREB phosphorylation, indicating an activation of CREB. Chromatin immunoprecipitation studies revealed a G-17-mediated increase in the interaction of beta-catenin with cyclin D1 CRE, which was attenuated by dnTCF4 and dnCREB. These results indicate that G-17 induces cyclin D1 transcription, via the activation of beta-catenin and CREB pathways.
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Affiliation(s)
- Anamika Pradeep
- Division of Molecular Cardiology, The Texas A and M University System Health Science Center, College of Medicine, Temple, TX 76504, USA
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22
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Olszewska-Pazdrak B, Ives KL, Park J, Townsend CM, Hellmich MR. Epidermal Growth Factor Potentiates Cholecystokinin/Gastrin Receptor-mediated Ca2+ Release by Activation of Mitogen-activated Protein Kinases. J Biol Chem 2004; 279:1853-60. [PMID: 14602717 DOI: 10.1074/jbc.m309481200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Small differences in amplitude, duration, and temporal patterns of change in the concentration of free intracellular Ca2+ ([Ca2+](i)) can profoundly affect cell physiology, altering programs of gene expression, cell proliferation, secretory activity, and cell survival. We report a novel mechanism for amplitude modulation of [Ca2+](i) that involves mitogen-activated protein kinase (MAPK). We show that epidermal growth factor (EGF) potentiates gastrin-(1-17) (G17)-stimulated Ca2+ release from intracellular Ca2+ stores through a MAPK-dependent pathway. G17 activation of the cholecystokinin/gastrin receptor (CCK(2)R), a G protein-coupled receptor, stimulates release of Ca2+ from inositol 1,4,5-triphosphate-sensitive Ca2+ stores. Pretreating rat intestinal epithelial cells expressing CCK(2)R with EGF increased the level of G17-stimulated Ca2+ release from intracellular stores. The stimulatory effect of EGF on CCK(2)R-mediated Ca2+ release requires activation of the MAPK kinase (MEK)1,2/extracellular signal-regulated kinase (ERK)1,2 pathway. Inhibition of the MEK1,2/ERK1,2 pathway by either serum starvation or treatment with selective MEK1,2 inhibitors PD98059 and U0126 or expression of a dominant-negative mutant form of MEK1 decreased the amplitude of the G17-stimulated Ca2+ release response. Activation of the MEK1,2/ERK1,2 pathway either by pretreating cells with EGF or by expression of constitutively active K-ras (K-rasV12G) or MEK1 (MEK1*) increased the amplitude of G17-stimulated Ca2+ release. Although EGF, MEK1*, and K-rasV12G activated the MEK1,2/ERK1,2 pathway, they did not increase [Ca2+](i) in the absence of G17. These data demonstrate that the activation state of the MEK1,2/ERK1,2 pathway can modulate the amplitude of the CCK(2)R-mediated Ca2+ release response and identify a novel mechanism for cross-talk between EGF receptor- and CCK(2)R-regulated signaling pathways.
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Affiliation(s)
- Barbara Olszewska-Pazdrak
- Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
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23
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Slice LW, Hodikian R, Zhukova E. Gastrin and EGF synergistically induce cyclooxygenase-2 expression in Swiss 3T3 fibroblasts that express the CCK2 receptor. J Cell Physiol 2003; 196:454-63. [PMID: 12891702 DOI: 10.1002/jcp.10304] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Over-expression of cyclooxygenase-2 (COX-2) has been demonstrated to be tumorigenic in transgenic mice. Chronic treatment with NSAIDs is chemoprotective for colorectal cancer. Gastrin is a growth factor for gastric mucosa and has been shown to promote proliferation of colorectal cells. Recent studies suggest that COX-2 expression levels could mediate the growth effects of gastrin. Here, we report that gastrin increased PGE2 secretion in Swiss 3T3 cells expressing the CCK2 receptor. Gastrin dose dependently induced COX-2 protein levels in a time dependent manner. COX-2 mRNA levels were rapidly induced by a dose dependent increase in gastrin. Prior treatment of the cells with the CCK2 receptor specific antagonist, L365,260, inhibited gastrin-induced COX-2 protein and mRNA expression. Pretreatment with L364,714, the CCK1 receptor specific antagonist did not block COX-2 induction by gastrin. Inhibition of de novo protein synthesis by cycloheximide did not block COX-2 mRNA induction by gastrin. Also, gastrin-dependent COX-2 expression did not require PKC activity, activation of ERK, or transactivation of EGFR. However, co-stimulation with EGF and gastrin synergistically induced COX-2 protein and mRNA expression and PGE2 secretion. Measurements of COX-2 mRNA stability and COX-2 gene transcription reveal that EGF significantly increased the half-life of COX-2 mRNA with only a slight increase in the COX-2 transcription rate. Conversely, gastrin significantly increased COX-2 gene transcription rates but did not enhance COX-2 mRNA stability.
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Affiliation(s)
- Lee W Slice
- Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, Greater Los Angeles VA Medical Center, University of California, Los Angeles, California, USA.
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24
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Castaño E, Gil J. 15-deoxy-delta12,14 prostaglandin J2 synergizes with phorbol ester to induce proliferation in Swiss 3T3 cells independently of peroxisome proliferator-activated receptor gamma and PGD2 receptors. J Cell Physiol 2003; 195:421-7. [PMID: 12704651 DOI: 10.1002/jcp.10250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
15-deoxy-Delta(12,14) prostaglandin J(2) (15dPGJ(2)), a peroxisome proliferator-activated receptor gamma (PPARgamma) ligand, induced synergistic stimulation of DNA synthesis in the presence of phorbol dibutyrate (PDB) in Swiss 3T3 cells. This effect was dose-dependent and the maximum response was obtained at 2 microM 15dPGJ(2), although higher concentrations of 15dPGJ(2) were cytotoxic. Furthermore, 15dPGJ(2) synergizes with PDB to induce cell-cycle progression and cyclin D(1) expression. Rosiglitazone and ciglitazone, two other agonists of PPARgamma, did not synergize with PDB to induce DNA synthesis, suggesting that activation of PPARgamma is not involved in 15dPGJ(2)-induced DNA synthesis. 15dPGJ(2) neither increased the levels of cAMP, nor changed the phosphorylation state of CREB, nor induced calcium mobilization, indicating that 15dPGJ(2) effects are independent of prostaglandin D(2) receptor (DP1 and DP2). Moreover, 15dPGJ(2) did not induce activation of PKB/AKT or activation of extracellular signal-regulated kinase (ERK). These results establish a proliferative role for 15dPGJ(2) in Swiss 3T3 cells independent of the activation of PPARgamma or the PGD(2) receptors.
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Affiliation(s)
- E Castaño
- Departament de Ciencies Fisiològiques II, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain
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25
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Waldron RT, Rozengurt E. Protein kinase C phosphorylates protein kinase D activation loop Ser744 and Ser748 and releases autoinhibition by the pleckstrin homology domain. J Biol Chem 2003; 278:154-63. [PMID: 12407104 DOI: 10.1074/jbc.m208075200] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Persistent activation of protein kinase D (PKD) via protein kinase C (PKC)-mediated signal transduction is accompanied by phosphorylation at Ser(744) and Ser(748) located in the catalytic domain activation loop, but whether PKC isoforms directly phosphorylate these residues, induce PKD autophosphorylation, or recruit intermediate upstream kinase(s) is unclear. Here, we explore the mechanism whereby PKC activates PKD in response to cellular stimuli. We first assessed in vitro PKC-PKD transphosphorylation and PKD activation. A PKD738-753 activation loop peptide was well phosphorylated by immunoprecipitated PKC isoforms, consistent with similarities between the loop and their known substrate specificities. A similar peptide with glutamic acid replacing Ser(748) was preferentially phosphorylated by PKCepsilon, suggesting that PKD containing phosphate at Ser(748) is rapidly targeted by this isoform at Ser(744). When incubated in the presence of phosphatidylserine, phorbol 12,13-dibutyrate and ATP, intact PKD slowly autophosphorylated in the activation loop but only at Ser(748). In contrast, addition of purified PKCepsilon to the incubation mixture induced rapid Ser(744) and Ser(748) phosphorylation, concomitant with persistent 2-3-fold increases in PKD activity, measured using reimmunoprecipitated PKD to phosphorylate an exogenous peptide, syntide-2. We also further examined pleckstrin homology domain-mediated PKD regulation to determine its relationship with activation loop phosphorylation. The high constitutive activity of the pleckstrin homology (PH) domain deletion mutant PKD-deltaPH was not abrogated by mutation of Ser(744) and Ser(748) to alanines, suggesting that one function of activation loop phosphorylation in the PKD activation mechanism is to relieve autoinhibition by the PH domain. These studies provide evidence of a direct PKCepsilon-PKD phosphorylation cascade and provide additional insight into the activation mechanism.
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Affiliation(s)
- Richard T Waldron
- Division of Digestive Diseases, Department of Medicine, The David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1786, USA
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