鼻咽癌细胞株中C-KIT表达和突变以及对Imatinib的反应性

背景与目的:我们先前报道了鼻咽癌组织中存在C-KIT表达和突变,但体外水平Imatinib是否对鼻咽癌细胞有增殖抑制作用及其机制尚不清楚。本研究评价了鼻咽癌细胞株中C-KIT表达和突变以及对Imatinib的反应性,探讨三者之间的相关性。方法:应用Western blot检测鼻咽癌细胞株CNE-1、CNE-2、Hone-1、C-666、SUNE-1、5-8F及鼻咽上皮细胞株NP-69的C-KIT表达情况,应用直接测序法检测CNE-1、CNE-2、Hone-1、C-666、SUNE-1、5-8F、NP-69的C-KIT基因突变情况,应用CCK-8试剂盒进行Imatinib对CNE-1、CNE-2、Hone-1、C-666、SUNE-1及5-8F的增殖抑制实验,应用Pearson相关分析和t检验分析鼻咽癌细胞株中C-KIT表达、突变和对Imatinib的反应性三者之间是否有相关性。结果:鼻咽癌CNE-1、CNE-2、Hone-1、C-666、SUNE-1及5-8F细胞株相对于鼻咽上皮细胞株NP-69存在C-KIT蛋白高表达。CNE-1、CNE-2、Hone-1、NP-69发现杂合IVS17+78T>C,C-666...     

CD8~+NKT细胞表面活化性受体NKG2D在肺癌患者外周血中的表达及临床意义

背景与目的 NKT细胞活化性受体NKG2D及sMICA是近来肿瘤免疫研究领域的热点之一。本研究旨在观察肺癌患者外周血中CD8+NKT细胞受体NKG2D表达水平的变化,并对NKG2D及sMICA进行相关性分析,探讨它们在肺癌免疫监视中的作用及临床意义。方法选择82例初发未治疗的肺癌患者,采用流式细胞术检测外周血CD8+NKT细胞活化性受体NKG2D的表达,并以45例健康人作对照,采用酶联免疫吸附法检测肺癌患者血清中sMICA的表达,分析NKG2D与肺癌临床生物学特征的关系。结果肺癌患者外周血中CD8+NKT细胞表面活化性受体NKG2D水平均低于对照组,差异有统计学意义(P<0.001)。随TNM分期的增加,NKG2D的表达率逐渐降低。其中IV期肺癌患者NKG2D的表达明显低于I期-II期及III期患者该受体的表达,差异有统计学意义(P<0.001)。肺Ca患者中吸烟人群外周血中CD8+NKT细胞受体NKG2D的表达较非吸烟者低,差异有统计学意义(P<0.05)。CD8+NKT细胞受体NKG2D与sMICA呈负相关(r=-0.598,P<0.001)。结论肺癌患者CD8+NKT细胞表面受体NKG2D在外周血中低表...     

双歧杆菌脂磷壁酸对凋亡抑制因子survivin表达及其调控基因的影响

目的探讨双歧杆菌脂磷壁酸（LTA）对结肠上皮细胞癌LoVo细胞内凋亡抑制因子survivin表达的影响及其调控机制。方法采用RT-PCR和Western blot方法分别检测经双歧杆菌LTA处理后LoVo细胞中survivin mRNA和survivin蛋白表达的变化;用Western blot检测PI3K／AKT细胞信号通路中关键蛋白激酶AKT的磷酸化型pAKT（Thr308）以及p53和PFEN表达的变化。结果结肠癌LoVo细胞中存在survivin mRNA和蛋白的高表达,经LTA处理后其表达水平均明显下降（P〈0．01）;AKT蛋白激酶活性在LTA处理后也明显降低（P〈0．01）;而与下调survivin蛋白相关的p53和PTEN表达上升（P〈0．01）,且呈现一定的剂量依赖性。结论双歧杆菌LTA可以通过抑制PI3K／AKT细胞信号通路的活性,促进p53的表达,抑制凋亡抑制蛋白survivin的活性,导致caspases酶活性升高,诱导了LoVo细胞凋亡的发生。     

Soy phytochemicals synergistically enhance the preventive effect of tamoxifen on the growth of estrogen-dependent human breast carcinoma in mice

The objective of this work was to determine the interactive effects between soy bioactive components and tamoxifen (TAM) on prevention of estrogen-dependent breast cancer (BRCA). We initially investigated the effects of soy isoflavone genistein and TAM on the growth and cell cycle progression of estrogen-dependent MCF-7 human BRCA cells, and on the expression of ERalpha, pS2 and EGFR genes in vitro. Genistein or TAM alone inhibited the growth of MCF-7 cells in part via G(1) phase arrest, but their combinations showed suggestive antagonistic effects. We further evaluated the effects of bioactive soy components and TAM on the growth inhibition of MCF-7 tumors in a clinically relevant breast tumor model. TAM and bioactive soy components, genistein and soy phytochemical concentrate (SPC), delayed the growth of MCF-7 tumors. The combination of TAM with genistein or SPC, especially at the lower dose of TAM, had synergistic effects on delaying the growth of MCF-7 tumors. Biomarker determination suggests that the combination of TAM and soy components may synergistically delay the growth of MCF-7 tumors via their combined effects on induction of tumor cell apoptosis and inhibition of tumor cell proliferation. In addition, genistein and TAM combination synergistically delayed the growth of breast tumor via decreased estrogen level and activity, and down-regulation of EGFR expression. The results from our studies suggest that further investigations may be warranted to determine if the combination of TAM and bioactive soy components may be used for prevention and/or treatment of estrogen-dependent BRCA.     

N-cadherin expression is a potential survival mechanism of gefitinib-resistant lung cancer cells

Non-small cell lung cancer (NSCLC) is a major subtype of lung cancer and is the most common and fatal cancer worldwide. Specific tyrosine kinase inhibitors for epidermal growth factor receptor (EGFR), such as gefitinib, have been effective in some NSCLC patients and are being used in the clinical setting as pioneer molecularly targeted cancer drugs. However, many patients have not responded to these drugs, and have acquired resistance after long-term treatment. To identify other potential NSCLC molecular targets, we used DNA microarrays to examine gene expression profiles of gefitinib-resistant PC9/ZD cells that are derived from gefitinib-sensitive PC9 cells and harbor a threonine to methionine mutation at codon 790 (T790M) in EGFR, a known mechanism of acquired resistance to gefitinib. We found that N-cadherin expression was significantly upregulated in PC9/ZD cells compared with PC9 cells. Inhibition of N-cadherin expression by siRNA or treatment with antibodies against N-cadherin induced apoptosis of PC9/ZD cells in association with reduced phosphorylation of Akt and Bad, a proapoptotic protein. Moreover, inhibition of Akt expression by siRNA or treatment with an inhibitor for phosphatidylinositol (PI)-3 kinase reduced survival of PC9/ZD cells. In addition, we found several N-cadherin-expressing lung cancer cells that showed inherent resistance to gefitinib treatment and reduced survival owing to siRNA-induced inhibition of N-cadherin expression. Thus, it appears that N-cadherin maintains the survival of the gefitinib-resistant lung cancer cells via the PI-3 kinase/Akt survival pathway. From these results, we propose that N-cadherin signaling contributes, at least in part, to the survival mechanisms of gefitinib-resistant NSCLC cells and that N-cadherin is a potential molecular target in the treatment of NSCLC.     

Discovery, synthesis, and pharmacological evaluation of spiropiperidine hydroxamic acid based derivatives as structurally novel histone deacetylase (HDAC) inhibitors

New spiro[chromane-2,4'-piperidine] and spiro[benzofuran-2,4'-piperidine] hydroxamic acid derivatives as HDAC inhibitors have been identified by combining privileged structures with a hydroxamic acid moiety as zinc binding group. The compounds were evaluated for their ability to inhibit nuclear extract HDACs and for their in vitro antiproliferative activity on different tumor cell lines. This work resulted in the discovery of spirocycle 30d that shows good oral bioavailability and tumor growth inhibition in an HCT-116 murine xenograft model.     

Lignans and other constituents from the roots of the Vietnamese medicinal plant Pseuderanthemum palatiferum

Two new lignans, palatiferin A (1) and palatiferin B (2), were isolated from the roots of Pseuderanthemum palatiferum, together with five known triterpenes, epifriedelanol (3), lupeol (4), lupenone (5), betulin (6), pomolic acid (7), and a dipeptide asperglaucide (8). Their structures were established from 2D?NMR and mass spectroscopy. The absolute configuration of 1 and 2 was proposed based on the comparison of their optical rotation activities with those of compounds with similar structures such as wodeshiol and paulownin. The new lignans, palatiferin A (1) and palatiferin B (2) exhibited a moderate cytotoxicity against KB and HepG2 cell lines. However, betulin and lupeol, two abundant compounds from the roots of P. palatiferum, showed cytotoxic and antimicrobial activities.