外周血中芳香烃受体及芳香烃代谢酶活性与乳腺癌关系的研究

背景与目的：大量研究表明,活化的芳香烃受体(aryl hydrocarbon receptor,AhR)可能参与了由多环芳烃诱导的乳腺癌的发生,AhR作为公认的配体激活的转录因子,可诱导多种酶表达。本研究旨在探讨芳香烃受体和芳香烃代谢酶在人体内蛋白水平与乳腺癌及其病理指标间的关系。方法：以1∶1配对进行病例对照研究,共收集65对血样,采用酶联免疫吸附法检测血液中芳香烃受体及芳香烃代谢酶蛋白水平,同时收集病理资料。计量资料使用秩和检验进行统计分析,相关性分析使用Spearman检验。结果：秩和检验发现对照组与病例组间醛脱氢酶(aldehyde dehydrogenase,ALDH)、细胞色素(cytochrome P450,CYP450)差异无统计学意义(Z=0.196,P=0.845;Z=0.269,P=0.788);AhR、醌氧化还原酶(quinone oxido-ereductase 1,NQO1)、谷胱甘肽-S-转移酶(glutatnione-S-transferases,GST)对照组平均浓度低于病例组,差异有统计学意义(Z=1.956,P=0.041;Z=2.627,P=0.009;Z=3.272,P=0.001)。相关性分析结果显示,病例组中AhR与GST和NQO1相关性较高(r=0.665,P<0.01;r=0.704,P<0.01)。以病理指标(ER、PR、HER-2)-、+、++、+++分组,发现以雌激素受体ER分组的AhR、GST蛋白表达水平差异有统计学意义(P<0.05)。结论：实验结果显示芳香烃受体及芳香烃代谢酶蛋白水平对乳腺癌发生可能有重要影响,检测酶蛋白水平可能对乳腺癌的早期发现有帮助,对治疗方案的选择及预后有一定意义。     

Cytochrome P450 1A1, cigarette smoking,and risk of endometrial cancer (United States)

Cytochrome P450 1A1 (CYP1A1) is involved in the metabolism of estradiol and the activation of polycyclic aromatic hydrocarbons found in tobacco products. Polymorphic variation in CYP1A1 activity may modify susceptibility to endometrial cancer through the oxidative metabolism of estradiol and the activation of tobacco-smoke constituents. We prospectively evaluated the associations between three common CYP1A1 polymorphisms and endometrial cancer risk, as well as the potential modification of these associations by cigarette smoking, in a case–control study nested within the Nurses’ Health Study. We investigated the MspI restriction-site polymorphism, a C → A transversion at nucleotide 4887 (Thr461Asn) and a A → G transition at nucleotide 4889 (Ile462Val) among 456 women with endometrial cancer and 1,134 matched controls. We used conditional logistic regression to calculate the adjusted odds ratios (OR) and 95% confidence intervals (CI) to quantify the risk of endometrial cancer among subjects who had at least one variant allele compared with that of subjects homozygous for the wild-type allele. We did not observe any statistically significant associations between the MspI, Thr461Asn or Ile462Val polymorphisms and endometrial cancer risk or any significant effect modification by cigarette-smoking status. These data suggest that these three polymorphisms are not important in determining genetic susceptibility to endometrial cancer, although larger sample sizes are needed to confirm these findings.     

Cytochrome P4501A1 genetic polymorphisms and breast cancer risk in Nigerian women

Summary In this case-control study based on 250 women with breast cancer and 250 age-matched controls, we sought to evaluate the role of four polymorphic variants in the CYP1A1 gene in breast cancer susceptibility in Nigerian women. Heterozygosity for the CYP1A1 M1 genotype (CYP1A1 M1 [T/C]) was associated with a 21% reduced risk of breast cancer (OR=0.79, 95% CI 0.46–1.40) while homozygosity for the genotype (CYP1A1 M1 [C/C]) conferred a non-significant 9% reduced risk of breast cancer. These risk profiles were not significantly altered in subgroup analysis by menopausal status. While heterozygosity for the CYP1A1 M3 genotype (T/C) conferred a non-significant 24% reduced risk of breast cancer (OR=0.76, 95% CI 0.47–1.22), homozygosity for the variant was associated a non-significant 1.95-fold increased risk of breast cancer (OR=1.95, 95% CI 0.24–6.01). Subgroup analysis showed a non-significant 11% reduced risk in premenopausal heterozygous carriers (OR=0.89, 95% CI 0.45–1.44) and a non-significant 6% increased risk of postmenopausal breast cancer for carriers of the CYP1A1 M3 (T/C) genotype. The CYP1A1 M2 (isoleucine to valine) polymorphism in exon 7 and CYP1A1 M4 (threonine to asparagine) variant in codon 461 of the CYP1A1 gene were found to be very rare in our study subjects. This study has shown that while the CYP1A1 M1 polymorphism conferred reduced risk of breast cancer, homozygosity for the CYP1A1 M3 (C/C) was associated with increased risk of breast cancer although these risks did not attain statistical significance.     

RNAi抑制ALK1对人胃腺癌SGC-7901细胞增殖的影响

背景与目的:人活化素受体样激酶-1(activin receptor-like kinase-1,ALK1)可促进内皮细胞增殖,与肿瘤内血管生成密切相关.本研究采用RNA干扰技术(RNA interference,RNAi)抑制ALK1表达,观察抑制效果以及抑制ALK1表达后对人胃癌细胞增殖的影响.方法:设计3条靶向ALK1基因的小干扰RNA(small interfering RNA,siRNA),克隆到真核表达质粒pGenesil-1,转染人胃癌细胞株SGC-7901.分别采用Real-time PCR和Western blot技术检测胃癌细胞ALK1 mRNA及其蛋白表达的变化,并检测细胞周期及生长曲线.结果:与阴性对照相比,第3条ALK1干扰RNA在mRNA及蛋白水平均可明显下调ALK1基因表达,并抑制SGC-7901细胞增殖.结论:RNAi技术导致的ALK1表达下调并抑制胃癌细胞增殖,ALK1可作为胃癌抗肿瘤治疗的理想靶点.     

Inhibitory effect of endothelin A receptor blockade on tumor growth and liver metastasis of a human gastric cancer cell line

Background With metastatic progression, gastric cancer is incurable. Using a DNA microarray, we performed differential gene expression analysis of established highly metastatic gastric cancer cell lines and compared the findings with those from a low-metastatic parental cell line. The results demonstrated that the endothelin A receptor (ET-A) gene was the only one from the highly metastatic cell lines that was generally up-regulated. Methods To investigate the role that ET-A plays in gastric cancer metastasis, we studied the effect of an ET-A-selective antagonist, YM598, on cell proliferation, tumor growth, and liver metastasis of the highly liver metastatic cell line AZ-H5c, established from the low metastatic human gastric cancer cell line AZ-521. Results An in vivo study using nude mice demonstrated that YM598 had a significant growth inhibition effect on AZ-H5c at doses of 0.5–10.0 mg/kg. The liver metastatic rate was also significantly reduced by YM598: control, 83.3%; 1 mg/kg dosage, 16.7%; 10 mg/kg, 20%; and pretreatment at 1 mg/kg, 16.7%. There was no evidence of gross toxicity resulting from the YM598 treatment. Conclusion The ET-A blockade by YM598 had a strong inhibitory effect against tumor growth and liver metastasis of the gastric cancer cell lines. These data suggest that YM598 has potential as a novel therapeutic agent for inhibiting liver metastasis of gastric cancer.     

Concurrent expression of aryl hydrocarbon receptor and CYP1A1 but not CYP1A1 MspI polymorphism is correlated with gastric cancers raised in Dalian, China

The frequency of cancer-associated m2m2- (C-) genotype of CYP1A1 and the factors contributing to the increased CYP1A1 expression in gastric cancers (GCs) are largely unknown. To address theses issues, PCR-restriction fragment length polymorphism (PCR-RFLP) was performed to elucidate the MspI polymorphism in 60 GC cases and 57 normal donor samples. The frequencies of m1m1-, m1m2- and m2m2-genotype were 43.3, 45 and 11.7% among GC patients and 45.6, 49.1 and 5.3% among the normal donors respectively, demonstrating no significant difference of them between cancer and control groups (χ²=0.343, P=0.558). The correlation of Aryl hydrocarbon receptor (AhR) with the frequent CYP1A1 expression in stepwise gastrocarcinogenesis was determined by RT-PCR, immunohistochemical staining (IHC) and Western blotting, using GC samples as well as their pre-malignant and non-cancerous counterparts. RT-PCR revealed that the AhR detection rates were 100, 94.12 and 85.17% in GC, pre-malignant and non-cancerous mucosa (P>0.05) respectively but the level of AhR expression in GCs was much higher than that of non-cancerous tissues. IHC showed that the frequencies of AhR detection were 94.87% (37/39) in GCs, 94.12% (16/17) in pre-malignant lesions and 50% (3/6) in non-cancerous mucosa, revealing significant difference in frequencies of AhR detection and levels of AhR expression between GC or pre-malignant group and non-cancerous one (P<0.05). The frequency of AhR nucleus translocation was significantly high in GCs (94.87%; 37/39) than that in pre-malignant (70.59%; 12/17) and especially in non-cancerous group (16.67%; 1/6). Co-existence of AhR nuclear translocation and CYP1A1 expressions were found in 82.70% (43/52) of GCs (r_s=0.437, P<0.01). Our results suggest (1) that CYP1A1 MspI polymorphism may not contribute to the high gastric cancer risk in Dalian region and (2) that enhanced AhR expression and especially its nuclear translocation may be a favorable factor for GC formation presumably via up-regulating CYP1A1 expression.     

Cryptotanshinone inhibits breast cancer cell growth by suppressing estrogen receptor signaling

Estrogen receptor (ER) is a major therapeutic target for the treatment of breast cancer, because of the crucial role of estrogen signaling deregulation in the development and progression of breast cancer. In this study, we report the identification of a novel ERα binding compound, cryptotanshinone (CPT), by screening the CADD database. We also show that CPT effectively inhibits estrogen-induced ER transactivation and gene expression of ER target genes. Furthermore, we showed that CPT suppressed breast cancer cell growth mainly in an ERα dependent manner. Finally, we confirmed the potential therapeutic efficiency of CPT using xenograft experiments in vivo. Taken together, our results describe a novel mechanism for the anticancer activity of CPT and provide supporting evidence for its use as a potential therapeutic agent to treat patients with ERα positive breast cancer.     

Exogenous morphine inhibits human gastric cancer MGC- 803 cell growth by cell cycle arrest and apoptosis induction

Morphine is not only an analgesic treating pain for patients with cancer but also a potential anticancer drug inhibiting tumor growth and proliferation. To gain better insight into the involvement of morphine in the biological characteristics of gastric cancer, we investigated effects on progression of gastric carcinoma cells and the expression of some apoptosis-related genes including caspase-9, caspase-3, survivin and NF-κB using the MGC-803 human gastric cancer cell line. The viability of cells was assessed by MTT assay, proliferation by colony formation assay, cell cycle progression and apoptosis by flow cytometry and ultrastructural alteration by transmission electron microscopy. The influences of morphine on caspase-9, caspase-3, survivin and NF-κB were evaluated by semi-quantitative RT-PCR and Western blot. Our data showed that morphine could significantly inhibit cell growth and proliferation and cause cell cycle arrest in the G2/M phase. MGC-803 cells which were incubated with morphine also had a higher apoptotic rate than control cells. Morphine also led to morphological changes of gastric cancer cells. The mechanism of morphine inhibiting gastric cancer progression in vitro might be associated with activation of caspase-9 and caspase-3 and inhibition of survivin and NF-κB.     

Hydrazinobenzoylcurcumin inhibits androgen receptor activity and growth of castration-resistant prostate cancer in mice

There is a critical need for therapeutic agents that can target the amino-terminal domain (NTD) of androgen receptor (AR) for the treatment of castration-resistant prostate cancer (CRPC). Calmodulin (CaM) binds to the AR NTD and regulates AR activity. We discovered that Hydrazinobenzoylcurcumin (HBC), which binds exclusively to CaM, inhibited AR activity. HBC abrogated AR interaction with CaM, suppressed phosphorylation of AR Serine81, and blocked the binding of AR to androgen-response elements. RNA-Seq analysis identified 57 androgen-regulated genes whose expression was significantly (p ≤ 0.002) altered in HBC treated cells as compared to controls. Oncomine analysis revealed that genes repressed by HBC are those that are usually overexpressed in prostate cancer (PCa) and genes stimulated by HBC are those that are often down-regulated in PCa, suggesting a reversing effect of HBC on androgen-regulated gene expression associated with PCa. Ingenuity Pathway Analysis revealed a role of HBC affected genes in cellular functions associated with proliferation and survival. HBC was readily absorbed into the systemic circulation and inhibited the growth of xenografted CRPC tumors in nude mice. These observations demonstrate that HBC inhibits AR activity by targeting the AR NTD and suggest potential usefulness of HBC for effective treatment of CRPC.     

乙醛脱氢酶1A1在胃癌组织中的表达及其临床意义

目的 探讨乙醛脱氢酶1A1（ALDH1A1）在胃癌组织中的表达及临床意义。方法 采用免疫组化法检测1072例胃癌组织及配对癌旁组织中ALDH1A1的表达,并分析其与临床病理特征及总生存时间（OS）的关系。结果 ALDH1A1在胃癌组织中的阳性表达率为49.9％（535/1072）,在癌旁组织中为43.3％（465/1072）,差异有统计学意义（P＜0.05）。 ALDH1A1在胃癌组织中的表达与年龄、浸润深度、分化程度、淋巴结转移及TNM分期有关（P＜0.05）。全组患者的中位OS为32.2个月。ALDH1A1阳性表达者为23.3个月,低于阴性表达者的60.4个月（P＜0.001）。Cox多因素分析显示,ALDH1A1表达、分化程度、TNM分期、年龄、淋巴结转移、癌栓、浸润深度和神经侵犯是影响OS的独立因素。结论ALDH1A1在胃癌组织中表达上调,且与胃癌患者预后相关,有可能成为反映胃癌预后新的肿瘤标志物。     

Suppression of the hypoxia inducible factor-1 function by redistributing the aryl hydrocarbon receptor nuclear translocator from nucleus to cytoplasm

The aryl hydrocarbon receptor nuclear translocator (ARNT) heterodimerizes with hypoxia inducible factor-1α (HIF-1α), followed by upregulation of genes that are essential for carcinogenesis. We utilized a novel peptide (Ainp1) to address whether the HIF-1α signaling could be suppressed by an ARNT-mediated mechanism. Ainp1 suppresses the HIF-1α-dependent luciferase expression in Hep3B cells and this suppression can be reversed by ARNT. Ainp1 reduces the interaction between ARNT and HIF-1α, suppresses the formation of the HIF-1 gel shift complex, and suppresses the ARNT recruitment to the vegf promoter. These effects are partly mediated by redistribution of the nuclear ARNT contents to the cytoplasm.     

NRP-1mAb对胃癌细胞BGC 823增殖的影响

目的 观察自主研发的抗NRP-1 b1／b2 IgG单克隆抗体（NRP 1mAb）对胃癌BGC 823细胞生长的影响,并初步探讨可能的作用机制。方法 实验室制备NRP-1mAb,采用SDS-PAGE检测纯度。采用0、25、100、200、400 μg／ml NRP-1 mAb培养胃癌BGC-823细胞,光学显微镜下观察细胞形态学变化;采用MTT法、集落形成实验、流式细胞术观察胃癌细胞BGC-823的增殖、集落形成和凋亡的情况;Western blotting法检测NRP 1mAb作用后Akt、p38、ERK、JNK信号蛋白磷酸化情况。结果 SDS-PAGE检测显示,NRP-1mAb的纯度在95％以上。光学显微镜观察显示,NRP-1mAb作用后,BGC-823细胞形态呈凋亡改变。MTT实验显示,NRP-1mAb抑制BGC-823细胞的增殖作用呈浓度和时间依赖性（P＜0.01）。集落形成实验显示,不同浓度NRP-1mAb均能显著抑制BGC-823细胞的集落形成,其抑制率呈浓度依赖性（P＜0.01）。流式细胞术检测显示,不同浓度NRP-1mAb均明显促进BGC-823细胞凋亡,且大部分集中在早期凋亡。Western blotting检测显示,BGC-823细胞的Akt磷酸化受到抑制, ERK、p38、JNK的磷酸化水平无明显变化。结论NRP-1mAb能抑制胃癌细胞BGC-823的生长、促进凋亡,可能与抑制Akt磷酸化有关。     

Latest therapeutic target for gastric cancer: Anthrax toxin receptor 1

Anthrax toxin receptor 1 (ANTXR1), also known as tumor endothelial marker 8, is a highly conserved cell surface protein overexpressed in tumor-infiltrating vessels. It was first found in vascular endothelial cells of human colorectal cancer. Although our understanding of its physiological function is limited, it has been found that ANTXR1 binds collagen and promotes migration of endothelial cells in vitro. ANTXR1 is upregulated in vessels of different tumor types in mice and humans, and is also expressed by tumor cells themselves in some tumors, such as gastric, lung, intestinal and breast cancer. Developmental angiogenesis and wound healing were not disturbed in ANTXR1 knockout mice, but compared with wild-type mice, growth of melanoma was impaired after ANTXR1 knockout, indicating that host-derived ANTXR1 can promote tumor growth on the basis of immune activity. Previous studies have shown that ANTXR1 vaccines or sublethal doses of anthrax toxin can inhibit angiogenesis, slow tumor growth and prolong survival. These studies suggest that ANTXR1 is necessary for tumor rather than physiological angiogenesis. It has been found that ANTXR1 plays an important role in tumor angiogenesisas well as in the growth and metastasis of many kinds of tumors. This article reviews the physiological function of ANTXR1 and its role in different kinds of cancer.     

Claudin-1 enhances tumor proliferation and metastasis by regulating cell anoikis in gastric cancer

Claudin-1 (CLDN1) is overexpressed in gastric cancer and correlated with tumor invasion, metastasis and poor outcome. Here, we both down and up regulated CLDN1 expression in gastric cancer cells to elucidate its role in gastric carcinogenesis and tumor progression. We found that deficiency of CLDN1 inhibited cells migration, invasion, and colony formation in vitro and tumorigenicity, metastasis in vivo. Also, CLDN1 promoted cell aggregation and increased anoikis resistance. Down or up regulation of CLDN1 was accompanied with changes of membrane β-catenin expression as well as Akt and Src activities. When β-catenin was up-regulated in CLDN1-KD cells, cell aggregation and anoikis resistance were restored, and Akt and Src signal pathways were re-activated. Taken together, these findings suggest that CLDN1 is oncogenic in gastric cancer and its malignant potential may be attributed in part to regulation of anoikis, by mediating membrane β-catenin-regulated cell-cell adhesion and cell survival.