CC Chemokine Receptor 9 Enhances Proliferation in Pancreatic Intraepithelial Neoplasia and Pancreatic Cancer Cells

Introduction  

Chemokine receptors may regulate the progression and metastasis of invasive malignancies. There are little data, however, regarding their role in premalignant lesions. Our objective was to determine the role of CC chemokine receptor 9 (CCR9) in pancreatic intraepithelial neoplasia (PanIN).     

RON,a Tyrosine Kinase Receptor Involved in Tumor Progression and Metastasis

Tyrosine kinase receptors mediate many critical cellular functions that contribute to tumor progression and metastasis and thus are potential targets for molecular-based cancer therapy. As has been found for many receptor tyrosine kinases, RON (recepteur dorigine nantais) and its ligand, macrophage-stimulating protein, have recently been implicated in the progression and metastasis of tumors. In in vitro experiments using colon and breast cancer cell lines, overexpression of RON led to increased invasion and migration of cancer cells and prevented apoptosis and anoikis. In addition, transgenic mice engineered to overexpress RON in the lung epithelium developed multiple pulmonary tumors, suggesting a role for RON in tumorigenesis. In human cancer specimens, increased RON expression has been demonstrated in colon, breast, ovarian, and lung tumors. Therefore, therapies designed to inhibit RON activation may hinder critical tumor survival mechanisms and play a role in the treatment of advanced disease.Published by Springer Science+Business Media, Inc. © 2005 The Society of Surgical Oncology, Inc.     

大黄酸对胰腺癌细胞增殖和迁移的影响及机制研究

目的:研究大黄酸对人胰腺癌细胞增殖和迁移的影响,并探讨其作用机制.方法:用不同浓度的大黄酸处理人胰腺癌MiaPaCa-2细胞,CCK8法检测大黄酸对MiaPaCa-2细胞增殖的影响;于常氧和缺氧条件下培养MiaPaCa-2细胞,Transwell法检测大黄酸对胰腺癌细胞迁移的影响,并用Western blot法检测细胞...     

极光激酶A通过调控Wnt信号通路影响胃癌细胞增殖和侵袭

目的:研究极光激酶A(AURKA)基因通过调控Wnt信号通路抑制胃癌细胞的增殖和侵袭的作用机制。方法:AURKA特异性抑制剂MLN8237(20μmol/L)处理SGC-7901胃癌细胞系作为实验组,以DMSO处理作为对照组,实时定量PCR(qRT-PCR)检测细胞内AURKA的表达水平,藉此验证该抑制剂效果;同时应用qRT-PCR和Western blotting方法检测Wnt信号通路关键蛋白β-catenin和EMT相关蛋白N-cadherin、E-cadherin和Twist表达水平,检测细胞周期变化,用Transwell法和平板克隆形成实验检测细胞侵袭和增殖。结果:PCR结构提示对照组细胞内AURKA的表达为1.00±0.13,实验组为0.36±0.09(P0.01);与对照组相比,实验组SGC-7901细胞内β-catenin(0.41±0.07)(P0.01)、N-cadherin(0.26±0.08)(P0.01)、Twist(0.33±0.12)(P0.01)表达水平降低,E-cadherin(4.05±0.96)表达水平上调(P0.05),Western blotting实验的结果与其一致,细胞周期实验结果示细胞出现了明显的G2/M期阻滞(P0.05);transwell实验结果示实验组(28.33±3.82)穿过基膜的细胞较对照组(83.67±4.28)明显减少(P0.05);平板克隆实验结果显示实验组克隆形成数(104.67±5.73)较对照组(417.00±7.25)明显减少(P0.05)。结论:AURKA可以通过下调Wnt信号通路活性抑制细胞侵袭、增殖过程,可作为提高胃癌临床化疗敏感性的潜在靶点。     

Oxytocin Receptor Signaling in Myoepithelial and Cancer Cells

Oxytocin (OT) plays a crucial role as a mediator of breast myoepithelial cell contraction, the process responsible for the ejection of milk during lactation, and is also involved in myoepithelial cell proliferation and postpartum mammary gland proliferation. Furthermore, although a number of breast cancer cells have oxytocin receptors (OTRs), it has been reported that OT stimulates, inhibits, or has no effect on cell proliferation. As these different effects seem to be mediated by different signaling pathways elicited by OTR stimulation, we here review the regulation of OTR signaling in different cell systems and discuss how understanding the molecular basis of receptor coupling specificity has become extremely important for understanding the role played by OTRs in regulating cell growth.     

Dimethylamino Parthenolide Enhances the Inhibitory Effects of Gemcitabine in Human Pancreatic Cancer Cells

Introduction

Gemcitabine is standard treatment for pancreatic cancer but has limited clinical benefit due to chemoresistance. Nuclear factor-kappaB (NF-??B) can promote chemoresistance and is therefore an attractive therapeutic target. We hypothesize that NF-??B suppression with the novel, orally bioavailable inhibitor dimethylamino parthenolide (DMAPT) will sensitize pancreatic cancer cells to gemcitabine.

Methods

BxPC-3, PANC-1, and MIA PaCa-2 human pancreatic cancer cell lines were treated with gemcitabine and/or DMAPT. Effects on the NF-??B pathway were determined by electrophoretic mobility shift assay, ELISA, or Western blot. Proliferation and apoptosis were measured by cell counts and ELISA, respectively. The effect of gemcitabine in vivo was determined using a MIA PaCa-2 heterotopic xenograft model.

Results

Gemcitabine induced NF-??B activity in BxPC-3, PANC-1, and MIA PaCa-2 cells and decreased the level of the NF-??B inhibitor I??B?? in BxPC-3 and PANC-1 cells. DMAPT prevented the gemcitabine-induced activation of NF-??B. The combination of DMAPT/gemcitabine inhibited pancreatic cancer cell growth more than either agent alone. Gemcitabine also induced intratumoral NF-??B activity in vivo.

Conclusions

DMAPT enhanced the anti-proliferative effects of gemcitabine in association with NF-??B suppression in pancreatic cancer cells in vitro. Furthermore, gemcitabine induced NF-??B activity in vivo, thus supporting the evaluation of NF-??B-targeted agents to complement gemcitabine-based therapies.     

表皮生长因子促进胰腺癌细胞侵袭和转移的实验研究

目的 探讨表皮生长因子（epidermal growthfactor，EGF）促进胰腺癌细胞侵袭和转移的分子机理。方法 EGF对胰腺癌细胞系NOR—P1的增殖、黏附及侵袭能力的影响分别用WST-1细胞增殖实验、细胞黏附实验和Transwell体外侵袭实验检测；MMP-9和MMP-2的活性及表达分别用明胶酶谱分析和Western印迹、RT—PCR检测；NF-κB活性用凝胶电泳迁移实验检测。结果 EGF能够明显促进胰腺癌细胞的侵袭能力，但对胰腺癌细胞的黏附力及增殖并无明显影响；EGF明显上调胰腺癌细胞的NF-κB和MMP-9的活性及表达，但对MMP-2活性及表达无影响；NF-κB抑制物四氢化吡咯二硫代氨基甲酸盐（PDTC）能够明显抑制EGF所诱导的NF-κB活性，同时也抑制EGF所诱导的MMP-9表达及胰腺癌细胞的侵袭力。结论 EGF通过活化NF-κB促进胰腺癌细胞的MMP-9的表达和侵袭力，采用NF-κB抑制剂PDTC阻断NF-κB通路能够降低胰腺癌细胞的侵袭力。     

Phosphorylated Insulin-Like Growth Factor 1 Receptor is Implicated in Resistance to the Cytostatic Effect of Gefitinib in Colorectal Cancer Cells

Introduction  

The ability of certain cancer cells to maintain signaling via the phosphoinositide-3-kinase/Akt and/or Ras/mitogen-activated protein kinase (MAPK) pathways has been repeatedly involved in resistance to epidermal growth factor receptor (EGFR) inhibition.     

Cardiopulmonary Bypass Decreases G Protein-Coupled Receptor Kinase Activity and Expression in Human Peripheral Blood Mononuclear Cells

Background: Cardiopulmonary bypass (CPB) has been implicated in the development of organ injury associated with cardiac surgery. At the molecular level, CPB is accompanied by a pronounced proinflammatory response including an increase in plasma interleukin (IL)-6. The IL-6 has been shown to be increased in rheumatoid arthritis, a chronic inflammatory disease, where it has been implicated in decreasing G protein-coupled receptor kinases (GRKs) in peripheral blood mononuclear cells. Since IL-6 is substantially increased after CPB, the study tested whether the increase of IL-6 during CPB leads to a decrease of GRKs in mononuclear cells. This is important because GRKs regulate the function of G protein-coupled receptors involved in inflammation.

Methods: Fifteen patients had blood withdrawn before CPB, 2 h after CPB, and on postoperative day one (POD1). Plasma IL-6 concentrations were determined by enzyme-linked immunosorbent assay. The GRK protein expression and activity were determined by Western blot and phosphorylation of rhodopsin using [[gamma]-32P] adenosine triphosphate, respectively.

Results: Plasma IL-6 increased over 20-fold after CPB and remained increased on POD1. Cytosolic GRK activity in mononuclear cells decreased by 39 +/- 29%; cytosolic GRK2 and membrane-bound GRK6 decreased by 90 +/- 15 and 65 +/- 43%, respectively. The GRK activity and expression of GRK2/GRK6 on POD1 returned to basal levels in many but not all patients.     

Angiotensin II Induces Vascular Endothelial Growth Factor in Pancreatic Cancer Cells Through an Angiotensin II Type 1 Receptor and ERK1/2 Signaling

Vascular endothelial growth factor (VEGF) is a crucial pro-angiogenic component in pancreatic ductal adenocarcinoma (PDA), and its high expression levels have been correlated with poor prognosis and early postoperative recurrence. We have recently shown that high levels of angiotensin II (AngII) type 1 receptor (AT1R) correlate and colocalize with VEGF in invasive PDA and that AngII induces VEGF expression in PDA cell lines. In this study, we explored the signaling mechanisms involved in the AngII-mediated VEGF induction and correlated AT1R and VEGF expression in noninvasive precursor lesions. An AT1R antagonist significantly (p < 0.05) inhibited the AngII-mediated induction of VEGF messenger RNA and protein in all PDA cell lines. AngII-VEGF induction was inhibited by the tyrosine kinase inhibitor genistein, suggesting a mitogen-activated protein kinase signaling mechanism. AngII activated the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), but not p38 or c-Jun NH2-terminal MAP kinases. Inhibition of ERK1/2 activation reduced the AngII-induced VEGF synthesis. Immunohistochemical analysis of precursor lesions showed increased expression of AT1R in most ductal cells undergoing metaplasia. Pancreatic intraepithelial neoplasms showed more intense AT1R staining when compared to intraductal papillary mucinous neoplasms, which showed heterogeneous immunoreactivity. VEGF followed the same distribution pattern of AT1R in both lesions. AT1R expression in the premalignant pancreatic lesions suggests its involvement in tumor progression and angiogenesis. Our mechanistic findings provide the first insight into an AngII-initiated signaling pathway that regulates PDA angiogenesis. An AT1R-mediated VEGF induction suggests the possibility of AT1R blockade as a novel therapeutic strategy to control angiogenesis in PDA. Presented as a poster presentation at the 48th Annual Meeting of the Society for Surgery of the Alimentary Tract, May 19–23, 2007 and an oral presentation at the Pancreas Club May 21st, 2007; Washington, DC.     

Angiotensin II Regulates the Expression of Monocyte Chemoattractant Protein-1 in Pancreatic Cancer Cells

Introduction  

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal cancers with an overall median survival of less than 9 months and a 5-year survival rate of less than 5%. Increasing evidence indicates that inflammation facilitates PDA growth.     

苦参碱对前列腺癌细胞增殖及雄激素受体功能的抑制作用

目的:探讨苦参碱(matrine)对雄激素依赖性前列腺癌细胞株(LNCaP)的增殖及雄激素受体(androgen re-ceptor,AR)表达的抑制作用。方法:分别用0.5、1.0、1.5、2.0、3.0g/L浓度的苦参碱作用于LNCaP细胞12、24、36h后MTT法检测细胞生长活性;台盼蓝拒染法测定细胞生长曲线;24h后流式细胞仪测定细胞周期变化;24h后Western印迹法检测细胞内AR的表达。结果:苦参碱能抑制LNCaP细胞的生长,呈剂量与时间依赖性,不同浓度苦参碱组之间与不同作用时间组之间的差异均有显著性意义(P<0.01)。苦参碱诱导LNCaP细胞出现剂量依赖性G2/M期阻滞(P<0.01);细胞内AR的表达随苦参碱剂量依赖性减少(P<0.01)。结论:苦参碱通过下调细胞内AR表达和阻滞细胞周期进展来抑制LNCaP细胞的体外生长。     

TRAIL and Triptolide: An Effective Combination that Induces Apoptosis in Pancreatic Cancer Cells

Introduction  

An emerging therapy in oncology is the induction of apoptotic cell death through anti-death receptor therapy. However, pancreatic cancer is resistant to apoptosis including anti-death receptor therapy. We have previously described how triptolide decreases resistance to apoptosis in pancreatic cancer cells in vitro and in vivo. We hypothesized that triptolide decreases tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance in pancreatic cancer cells. The aim of this study was to evaluate the effects that combined therapy with TRAIL and triptolide have on different parameters of apoptosis.