口腔鳞癌中p16/CDK4/cyclinD1/pRb通路的表达及其意义

目的分析口腔黏膜鳞状细胞癌(OSCC)中pRb、CDK4c、yclinD1、p16INK4a等细胞周期调控因子的表达状况和相互间的联系及其临床意义。方法采用免疫组化SP法,研究47例OSCC及10例正常口腔黏膜中pRb、CDK4c、yclinD1和p16INK4a的表达情况,并结合随访资料进行相关性分析。结果47例OSCC中,pRb、CDK4、cyclinD1和p16INK4a阳性表达率分别为55%、60%、74%和38%,与正常口腔黏膜中的表达有显著差异(P<0.05)。cyclinD1的表达和淋巴结转移有密切关系(P<0.05),p16和pRb呈负相关(r=-0.312)。结论p16/Rb通路蛋白的异常表达和OSCC的发生有密切的关系;cyclinD1可作为OSCC预后的辅助性指标之一。     

牙髓卟啉单胞菌脂多糖对成骨细胞p38丝裂原活化蛋白激酶和细胞外信号调节激酶1、2表达的影响

目的:探讨牙髓卟啉单胞菌(P.e)脂多糖(LPS)对小鼠成骨细胞株MC3T3-E1细胞ERK1/2和p38表达的影响。方法:用10μg/mL的P.e-LPS分别作用于成骨细胞0、5、15、30、60、180 min,应用蛋白质印迹技术检测成骨细胞内磷酸化ERK1/2和p38表达水平的变化。采用SPSS11.0软件包对结果进行单因素方差分析和Dunnett t检验。结果:10μg/mL的P.e-LPS刺激后,成骨细胞内p38迅速被活化,5～30 min为激活高峰(P<0.01),60 min后基本恢复至正常水平;ERK1/2磷酸化水平在P.e-LPS刺激5 min后明显增加,15 min后磷酸化水平最高(P<0.01),30 min后磷酸化水平下降。结论:P.e-LPS可诱导成骨细胞MC3T3-E1的p38和ERK1/2蛋白表达增强,Pe-LPS可能通过p38和ERK1/2对成骨细胞发挥作用。     

Expression of p21 (Waf1/Cip1) in head and neck cancer in relation to proliferation, differentiation, p53 status and cyclin D1 expression

p21 (Waf1/Cip1) is a critical downstream effector in the p53-dependent pathway of growth control and causes growth arrest through inhibition of cyclin-dependent kinases. In this study 67% of 43 head and neck squamous cell carcinoma (HNSCC) and 60% of 15 tumour-adjacent oral dysplasias overexpressed p21 by immunohistochemical staining. Overexpression of p21 in HNSCC was independent of the presence of functional p53, as assessed by analysis of mutations and loss of heterozygosity and by immunohistochemistry. Rather, the expression pattern of p21 was associated with differentiation. Furthermore, in most tumours, the p21 positive cells did not incorporate bromodeoxyuridine (BrdU), which indicates inhibition of proliferation by p21 in these cells. In some tumours, p21 was also expressed in proliferating cells. In these latter tumour cells, cyclin D1 was frequently expressed as well. Therefore, we suggest that expression of cyclin D1 might overcome the inhibitory effect of p21 in these cells.     

Involvement of P2X(7) purinergic receptor and MEK1/2 in interleukin-8 up-regulation by LL-37 in human gingival fibroblasts

Montreekachon P, Chotjumlong P, Bolscher JGM, Nazmi K, Reutrakul V, Krisanaprakornkit S. Involvement of P2X ₇ purinergic receptor and MEK1/2 in interleukin‐8 up‐regulation by LL‐37 in human gingival fibroblasts. J Periodont Res 2011; 46: 327–337.© 2011 John Wiley & Sons A/S Background and Objective: The antimicrobial peptide LL‐37, derived from human neutrophils, can directly chemoattract leukocytes and up‐regulate the expression of several immune‐related genes in various cell types. In this study, we wanted to determine the immunoregulatory effect of LL‐37 on interleukin‐8 (IL‐8) expression in human gingival fibroblasts (HGFs) and to characterize intracellular signaling pathway(s) and receptor(s) involved in IL‐8 induction. Material and Methods: Cultured fibroblasts were treated with different concentrations of LL‐37 or interleukin‐1β (IL‐1β), as a positive control, for specific periods of time in the presence or absence of various inhibitors. RT‐PCR and real‐time PCR were conducted to analyze the expression of IL‐8 mRNA, and the IL‐8 levels in cell‐free culture media were measured using ELISAs. The MTT assay was performed to determine the cytotoxicity of LL‐37. Results: Nontoxic concentrations of LL‐37 (up to 10 μm ) and IL‐1β significantly up‐regulated the expression of IL‐8 mRNA in a dose‐dependent manner (p < 0.05). The IL‐8 protein levels were consistently significantly elevated in conditioned media of LL‐37‐treated HGFs (p < 0.05). IL‐8 up‐regulation by LL‐37 was completely abrogated by 20 μm U0126, consistent with transient phosphorylation of p44/42 MAP kinases. Moreover, pretreatment with Brilliant Blue G (a selective antagonist of the P2X₇ receptor) and the neutralizing antibody against P2X₇ blocked IL‐8 up‐regulation in a dose‐dependent manner, consistent with expression of the P2X₇ receptor in HGFs. Conclusion: These findings indicate that LL‐37 induces IL‐8 expression via the P2X₇ receptor and the MEK1/2‐dependent p44/42 MAP kinases in HGFs, suggesting both direct and indirect involvement of LL‐37 in neutrophil recruitment into an inflammatory site within diseased periodontal tissues.     

IGF1通过BMP2-Smad1/5信号通路调控犬上颌窦黏膜干细胞成骨分化

目的探讨骨形态形成蛋白2(bone morphogenetic protein2,BMP2)-Smad1/5及p38MAPK信号通路在胰岛素样生长因子1(insulin-like growth factor 1,IGF1)介导的促犬上颌窦黏膜干细胞(maxillary sinus membrane stem cells,MSMSCs)成骨分化中的作用。方法构建表达胰岛素样生长因子1(insulin-like growth factor1,IGF1)基因的重组腺病毒载体(recombinant adenovirus,rAdv)Ad-IGF1。感染Ad-IGF1的犬上颌窦黏膜干细胞,经成骨诱导培养后,qRT-PCR和Western blot检测BMP-Smads信号通路中重要信号蛋白Smad1/5的磷酸化水平和BMP2蛋白的表达;免疫组化观察磷酸化Smad1/5核转位情况;qRT-PCR及Western blot检测BMP-Smads通路抑制剂Noggin和p38MAPK信号通路抑制剂SB203580对IGF1介导的促犬MSMSCs成骨分化的影响。结果成功构建IGF1基因表达重组腺病毒载体Ad-IGF1;感染Ad-IGF1的犬MSMSCs,经成骨诱导培养后,Smad1/5的磷酸化水平和BMP2蛋白的表达升高,IGF1可促使Smad1/5核转位;BMP-Smads信号通路抑制剂Noggin可抑制Smad1/5的磷酸化,降低成骨标志物Runx2、OPN和ALP mRNA的表达,钙结节形成减少。p38MAPK信号通路抑制剂SB203580不能降低Ad-IGF1犬MSMSCs的p38磷酸化水平,亦不能降低成骨标志物Runx2、OPN和ALP mRNA的表达。结论犬MSMSCs成骨分化过程中,IGF1通过经典的Smads蛋白依赖性信号转导通路BMP2-Smad1/5促进成骨,而Smads蛋白非依赖性信号转导通路p38MAPK在IGF1介导的犬MSMSCs成骨过程中可能并不发挥作用。