Expression of eukaryotic initiation factor 4E in gastric adenocarcinoma and its association with clinical outcome

BACKGROUND AND OBJECTIVES: Overexpression of eIF4E can result in oncogenic transformation and uncontrolled growth of mammalian cells, presumably by facilitating the expression of growth-control gene products, which are normally translationally repressed. Overexpression of eIF4E was present in human breast carcinoma and human head and neck squamous cell carcinoma, and may be of prognostic value in breast carcinomas. In order to elucidate the clinical significance of eIF4E expression, this study was conducted to quantify expression of eIF4E in human gastric cancer tissue and correlate them with clinicopathological factors and patient survival. METHODS: Specimens from sixty-nine patients with gastric adenocarcinoma were analyzed and eIF4E overexpression was quantified by Western blot analysis. Quantification of eIF4E levels in cancer was expressed relative to controls from non-tumorous mucosa of the same patients. Confirmation of eIF4E overexpression at the cellular level was performed using immunohistochemical staining. The association of clinicopathologic factors and survival with eIF4E expression was analyzed. RESULTS: In non-tumorous parts of specimens, overexpression of eIF4E was always present in gastric glands but not in gastric pits lining mucosa, and it was also expressed in the areas of intestinal metaplasia and dysplasia. In the 69 specimens, the mean eIF4E expression was 5.77 +/- 8.55-fold (mean +/- standard deviation), ranged from from 0.1-fold to 38-fold. The degree of eIF4E expression appeared to be independent of invasion depth of tumor, lymph node metastasis, Lauren classification, Borrmann types, and Helicobacter pylori infection. Marked overexpression of eIF4E (more than seven-fold) was correlated with tumor vascular invasion (P = 0.046, Fisher exact-test). The survival rate of the patients with underexpression or mild overexpression of eIF4E (less than sevenfold) was significantly higher than that with marked eIF4E overexpression (more than sevenfold) (P = 0.01734, log rank test). CONCLUSIONS: Marked eIF4E overexpression in gastric cancer was found to be associated with vascular invasion. The prognosis for gastric cancer patients with marked overexpression of eIF4E was worse than those with underexpression. It may serve as an additional prognostic and therapeutic factor in gastric cancer, and deserves further investigation.     

真核细胞翻译起始因子4E在肾癌细胞中的表达及意义

目的:探讨真核细胞翻译起始因子4E（eukaryotic translation initiation factor 4E,eIF4E）在人肾癌细胞中的表达及意义。方法:采用Western blot法检测不同人肾癌细胞系中eIF4E和phospho-eIF4E蛋白的表达水平。siRNA转染肾癌细胞敲除eIF4E,检测肾癌细胞生长。Western blot法检测雷帕霉素处理过的肾癌细胞中phospho-eIF4E和Akt的表达。结果:在肾癌细胞系中786-0、769-P 和OS-RC-2中,eIF4E 和phospho-eIF4E基因及蛋白表达明显高于人肾细胞系组（P<0.05）。敲除肾癌细胞eIF4E基因可抑制肾癌细胞的生长。雷帕霉素处理过的肾癌细胞phospho-eIF4E和Akt的表达明显升高。结论:eIF4E和phospho-eIF4E在肾癌细胞中高表达,可促进肾癌细胞生长,与肾癌的进展密切相关。     

HS3ST1对肺癌细胞增殖、迁移、侵袭及顺铂耐药的作用机制研究

目的:研究HS3ST1对肺癌细胞A549增殖、迁移、侵袭及顺铂耐药的影响.方法:利用慢病毒感染并构建HS3ST1过表达细胞株;利用Western blot、RT-PCT检测HS3ST1的表达;利用CCK8实验、Transwell迁移实验和细胞毒性实验检测HS3ST1对A549细胞增殖、迁移、侵袭和顺铂耐药的影响;利用W...     

Overexpression of the eukaryotic translation initiation factor 4G (eIF4G-1) in squamous cell lung carcinoma

eIF4G-1 belongs to the family of translational initiation factors and is recognized as the central organizing protein in recruitment of mRNA during translational initiation. Previously published studies have provided some evidence that overexpression of translational factors is a general event in the process of carcinogenesis. We have characterized the expression of the eIF4G-1 protein in 33 squamous cell carcinoma (SCC) of the lung by Western blotting. Overexpression of the eIF4G-1 protein was detected in 61% of the tumors compared to the respective normal lung tissue. In addition, we analyzed the expression of this protein by immunohistochemistry in 138 SCC of the lung using a newly generated antibody that is specific for eIF4G-1 as determined by Western blotting. This anti-eIF4G-1 antibody was suitable for the immunohistochemistry of paraffin-embedded tissues. There is a strong cytoplasmic staining detected in the tumor areas that is consistent with the cytoplasmic localization of the translation factor eIF4G-1. In 72% of the examined tissue sections of SCCs of the lung, we detected an overexpression of the eIF4G-1 protein compared to the surrounding connective tissue. Two tumors that were analyzed by both methods showed an overexpression of eIF4G-1 both with Western blot analysis and immunohistochemical staining. Overexpression of eIF4G-1 may result in an increased amount of the translation initiation complex eIF4F, which in turn may activate the translation of the same target mRNAs as eIF4E.     

Inhibition of mitochondrial glutaminase activity reverses acquired erlotinib resistance in non-small cell lung cancer

The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) erlotinib has been approved based on the clinical benefit in non-small cell lung cancer (NSCLC) patients over the past decade. Unfortunately, cancer cells become resistant to this agent via various mechanisms, and this limits the improvement in patient outcomes. Thus, it is urgent to develop novel agents to overcome erlotinib resistance. Here, we propose a novel strategy to overcome acquired erlotinib resistance in NSCLC by inhibiting glutaminase activity. Compound 968, an inhibitor of the glutaminase C (GAC), when combined with erlotinib potently inhibited the cell proliferation of erlotinib-resistant NSCLC cells HCC827ER and NCI-H1975. The combination of compound 968 and erlotinib not only decreased GAC and EGFR protein expression but also inhibited GAC activity in HCC827ER cells. The growth of erlotinib-resistant cells was glutamine-dependent as proved by GAC gene knocked down and rescue experiment. More importantly, compound 968 combined with erlotinib down-regulated the glutamine and glycolysis metabolism in erlotinib-resistant cells. Taken together, our study provides a valuable approach to overcome acquired erlotinib resistance by blocking glutamine metabolism and suggests that combination of EGFR-TKI and GAC inhibitor maybe a potential treatment strategy for acquired erlotinib-resistant NSCLC.     

HGF诱导不同EGFR基因型非小细胞肺癌细胞对厄洛替尼的耐药

目的：探究肝细胞生长因子（hepatocyte growth factor,HGF） 体外诱导不同EGFR基因型非小细胞肺癌（non-small cell lung cancer,NSCLC）细胞对厄洛替尼的耐药及其可能的机制。方法：用HGF、厄洛替尼单独或联合处理人NSCLC细胞株PC9（EGFR突变型,敏感株）、H292（EGFR野生型,敏感株）、A549（EGFR野生型,原发性耐药株）,实验分为四组：C组（不加药对照组）、H组（HGF处理）、E组（厄洛替尼处理组）、HE组（HGF+厄洛替尼联合处理组）。MTT法检测其对细胞增殖的影响,流式细胞术检测其对细胞周期和凋亡的影响,Western blotting检测其对细胞中c-Met、EGFR、ErbB3及其磷酸化蛋白表达的影响。结果：厄洛替尼对3种细胞增殖抑制的作用均呈浓度依赖性,HGF处理能够缓解厄洛替尼对瘤细胞增殖的抑制作用。3种细胞的HE组凋亡率均显著低于E组（均P<0.05）。厄洛替尼阻滞3种细胞周期于G1期,对于H292、A549细胞,HE组G0/G1期比例显著低于E组（P<0.05）。HE组p-Met蛋白含量较E组显著升高（P<0.05）,而p-EGFR和p-ErbB3表达无显著差异（P>0.05）。结论：在体外,HGF能够诱导不同EGFR基因型NSCLC细胞株对厄洛替尼耐药,其机制可能与其诱导c-Met磷酸化活化有关。     

肺耐药蛋白LRP在肺癌中的表达及意义

目的:检测LRP在不同分化阶段肺癌组织中的表达,探讨肺癌分化与LRP之间的关联;干扰LRP后,观察其对肺癌细胞A549侵袭能力的影响及其可能的分子机制.方法:应用免疫荧光检测肺癌组织中LRP蛋白及表达分布,Western blot检测肺癌组织及癌旁组织中LRP蛋白表达.通过RNAi技术干扰LRP后,运用RT-PCR、Western blot技术,观察干扰LRP基因效率,检测LRP在A549细胞的表达及对细胞侵袭能力的影响;同时用Western blot方法检测ERK及AKT信号通路、MMP金属蛋白酶及凋亡蛋白的表达.结果:肺癌中LRP阳性率与组织学分级相关,在低分化、中分化、高分化肺癌组织及癌旁组织中表达率分别为60.6％、39.3％、18.3％、8.3％,肺癌组织中LRP蛋白表达量明显高于癌旁组织.LRP-siRNA转染组侵袭率为(60.4±6.4)％高于对照组的(50.5±4.4)％,差异显著(P＜0.05).LRP-siRNA转染组AKT和ERK1/2磷酸化水平明显下降;MMP-2和MMP-9蛋白的表达水平受到抑制;凋亡相关蛋白Bcl-2降低,Bax升高.结论:LRP表达与肺癌的组织学分级有关,LRP蛋白有可能是肺癌浸润和转移的一个重要参考指标,可为肺癌治疗提供潜在的靶点.     

非小细胞肺癌PC-9细胞厄洛替尼耐药潜在机制的RNA测序分析

目的:通过RNA测序分析比较亲本PC-9细胞和厄洛替尼获得性耐药PC-9细胞(PC-9/ER)表达谱的差异,揭示非小细胞肺癌(NSCLC)表皮生长因子受体酪氨酸激酶抑制剂(EGFR-TKI)耐药的潜在机制。方法:采用间歇诱导方法,建立PC-9/ER耐药细胞株,通过MTT实验绘制厄洛替尼药物浓度-细胞存活率曲线。通过RNA测序分析PC-9/ER细胞的差异表达基因并进行GO和KEGG功能富集分析;通过qRT-PCR进一步筛选可能参与EGFR-TKI耐药的潜在基因或可能的靶点。结果:厄洛替尼对PC-9/ER细胞增殖的抑制率显著低于PC-9细胞的抑制率,PC-9/ER细胞的耐药指数为41.92。与PC-9细胞相比,RNA测序PC-9/ER细胞筛选出1 028个差异表达基因,其中720个基因表达上调,308个基因表达下调,而且差异表达基因显著富集在PI3K-AKT通路和癌症通路。qRT-PCR验证差异表达基因的转录水平与测序结果基本一致。结论:ST6GALNAC3、CYP1A1、PAPPA2、INHBE和ACSS3等基因可能参与EGFR-TKI的耐药过程,针对PC-9/ER细胞差异表达基因的后续...     

circKDM4C对肺癌细胞增殖和迁移侵袭影响

目的 本研究探讨circKDM4C在肺癌中的表达及生物学功能.方法 通过qRT-PCR检测circKDM4C在肺癌细胞系A549、H1299、H1650、H1975及肺正常上皮细胞BEAS-2B中的表达.siRNA转染A549和H1975,沉默circKDM4C,获得4组细胞系,分别为A549 si-circKDM4C...     

eIF4E binding protein 1 expression is associated with clinical survival outcomes in colorectal cancer

eIF4E binding protein 1 (4E-BP1), is critical for cap-dependent and cap-independent translation. This study is the first to demonstrate that 4E-BP1 expression correlates with colorectal cancer (CRC) progression. Compared to its expression in normal colon epithelial cells, 4E-BP1 was upregulated in CRC cell lines and was detected in patient tumor tissues. Furthermore, high 4E-BP1 expression was statistically associated with poor prognosis. Hypoxia has been considered as an obstacle for cancer therapeutics. Our previous data showed that YXM110, a cryptopleurine derivative, exhibited anticancer activity via 4E-BP1 depletion. Here, we investigated whether YXM110 could inhibit protein synthesis under hypoxia. 4E-BP1 expression was notably decreased by YXM110 under hypoxic conditions, implying that cap-independent translation could be suppressed by YXM110. Moreover, YXM110 repressed hypoxia-inducible factor 1α (HIF-1α) expression, which resulted in decreased downstream vascular endothelial growth factor (VEGF) expression. These observations highlight 4E-BP1 as a useful biomarker and therapeutic target, indicating that YXM110 could be a potent CRC therapeutic drug.     

乳腺癌组织中eIF-4E基因对VEGF-C表达及淋巴转移的影响

目的:探讨人乳腺癌组织中真核细胞起始因子-4E(eIF-4E)对特异性淋巴管内皮生长因子C(VEGF-C)表达及乳腺癌淋巴转移的影响。方法:分别应用Westernblot法和免疫组化SP法检测57例乳腺癌组织中eIF-4E蛋白水平及VEGF-C表达,VEGFR-3抗体免疫染色计数乳腺癌微淋巴管密度(LMVD)。结果:34例淋巴结阳性组织中eIF-4E水平显著高于淋巴结转移阴性组(10.11±0.30和5.94±0.23,t=5.37,P<0.01)。VEGF-C在淋巴结阳性组染色强度明显增高(4.20±0.98),同时VEGFR-3阳性淋巴管密度提高(25.28±5.33),与淋巴结阴性组(2.57±0.88和17.40±4.87)比较差异有统计学意义,t值分别为2.18和2.41,P值均<0.05。相关分析表明,eIF-4E水平与VEGF-C表达及淋巴结转移呈正相关。结论:eIF-4E可能通过上调VEGF-C的表达诱导乳腺癌淋巴管的生成,进而调控乳腺癌淋巴结转移。eIF-4E可作为判定乳腺癌淋巴结转移的参考指标。     

Eukaryotic initiation factor 4E variants alter the morphology, proliferation, and colony-formation properties of MDA-MB-435 cancer cells

Eukaryotic initiation factor 4E (eIF4E) binds to the 5' m(7)G cap of mRNAs and is a focal point of regulation of initiation of mRNA translation. High levels of expression of eIF4E in many epithelial cancers, including breast, head and neck, colon, and bladder, correlate with increased tissue invasion and metastasis. To further examine the role of eIF4E in the biology of cancer cells, variants of eIF4E with impaired 5' cap binding function were expressed in MDA-MB-435 carcinoma cells. Cell lines overexpressing variants of eIF4E had impaired growth properties and exhibited a different morphology compared to cells expressing similar amounts of exogenous wild-type eIF4E or control cells. Cells expressing variant eIF4E did not form foci in culture and produced smaller colonies in soft agar compared to cells expressing wild-type eIF4E. In addition, analysis of polyribosomes for vascular endothelial growth factor (VEGF) mRNA demonstrated a shift from translationally active to inactive fractions in variant eIF4E cells, while GAPDH mRNA did not. The long G-C rich 5' untranslated region of VEGF mRNA is a feature of other mRNAs encoding growth regulating proteins that are predicted to have their translation enhanced by increases in eIF4E; whereas mRNA with shorter and less structured 5' UTRs, like that of GAPDH, are predicted to be largely unaffected. These data suggest that targeting the 5' cap-binding domain of eIF4E may be a viable option to slow cancer cell growth and alter the malignant phenotype.     

MiR-21 overexpression is associated with acquired resistance of EGFR-TKI in non-small cell lung cancer

Background and purpose

With the increasing use of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) in patients with advanced non-small cell lung cancer (NSCLC), its acquired resistance has become a major clinical problem. Recent studies revealed that miR-21 was involved into the resistance of cytotoxic agents. The aim of this study was to investigate its role in the acquired resistance of NSCLC to EGFR-TKI.

Methods

EGFR-TKI-sensitive human lung adenocarcinoma cell line PC9 and the acquired resistant cell line, PC9R, were used. Lentiviral vectors were used to infect PC9 or PC9R to regulate the miR-21 expression. The expression of targeted proteins PTEN and PDCD4 was controlled by RNA interference. MicroRNA array, RT-PCR and TaqMan MicroRNA Assays were used to detect miR-21 expression. The MTT and Annexin V assays were used to determine proliferation and apoptosis. Western Blot and immunohistochemistry were used to analyze target protein expression (PTEN, PDCD4, Akt, p-Akt). We also constructed PC9R xenograft tumor model to observe the relationship between miR-21 and EGFR-TKI resistance in vivo and validated it in the clinical serum specimens of NSCLC patients treated with EGFR-TKI.

Result

MiR-21 was overexpressed in the EGFR-TKI resistant cell line PC9R relative to PC9. The level of miR-21 was reversely correlated with the expression of PTEN and PDCD4 and positive correlated with PI3K/Akt pathway. Inhibiting miR-21 with lentivirus vector induces apoptosis in PC9R cell line and inhibiting miR-21with ASO suppressed tumor growth in nude mice treated with EGFR-TKI. Furthermore, serum miR-21 expression in NSCLC patients treated with EGFR-TKI was significantly higher at the time of acquiring resistance than at baseline (p < 0.01).

Conclusion

miR-21 is involved in acquired resistance of EGFR-TKI in NSCLC, which is mediated by down-regulating PTEN and PDCD4 and activating PI3K/Akt pathway.     

肺癌细胞中RASSF4的高表达抑制肺癌细胞的增殖和侵袭能力

目的:探讨RASSF4在肺癌中的增殖和侵袭能力。方法:向肺癌细胞系H460和A549中导入RASSF4的cDNA质粒后,通过MTT、克隆形成实验、基质胶侵袭实验、流式细胞术等方法检测肺癌细胞的生长和侵袭能力。结果:RASSF4能够通过下调MMP2、MMP9和cyclinD1的表达,抑制肺癌细胞的侵袭、增殖及克隆形成能力。结论:RASSF4在肺癌细胞中通过抑制细胞生长及侵袭能力发挥重要的肿瘤抑制功能。     

4EGI-1 targets breast cancer stem cells by selective inhibition of translation that persists in CSC maintenance,proliferation and metastasis

Cancer death is a leading cause of global mortality. An estimated 14.1 million new cancer cases and 8.2 million cancer deaths occurred worldwide in 2012 alone. Cancer stem cells (CSCs) within tumors are essential for tumor metastasis and reoccurrence, the key factors of cancer lethality. Here we report that 4EGI-1, an inhibitor of the interaction between translation initiation factors eIF4E1 and eIF4G1 effectively inhibits breast CSCs through selectively reducing translation persistent in breast CSCs. Translation initiation factor eIF4E1 is significantly enhanced in breast CSCs in comparison to non-CSC breast cancer cells. 4EGI-1 presents increased cytotoxicity to breast CSCs compared to non-CSC breast cancer cells. 4EGI-1 promotes breast CSC differentiation and represses breast CSC induced tube-like structure formation of human umbilical vein endothelial cells (HUVECs). 4EGI-1 isomers suppress breast CSC tumorangiogenesis and tumor growth in vivo. In addition, 4EGI-1 decreases proliferation in and induces apoptosis into breast CSC tumor cells. Furthermore, 4EGI-1 selectively inhibits translation of mRNAs encoding NANOG, OCT4, CXCR4, c-MYC and VEGF in breast CSC tumors. Our study demonstrated that 4EGI-1 targets breast CSCs through selective inhibition of translation critical for breast CSCs, suggesting that selective translation initiation interference might be an avenue targeting CSCs within tumors.     

非小细胞肺癌组织中ABCG4表达与耐药的相关性研究

目的 检测ABCG4 mRNA和蛋白在非小细胞肺癌（NSCLC）组织中的表达,分析其表达与病理类型及NSCLC细胞耐药的相关性,为研究其耐药机制提供理论基础。方法 采用免疫组化染色、RT-PCR及Western blotting检测ABCG4在NSCLC组织中的表达;MTT法检测NSCLC对化疗药物的敏感性,分析药物敏感性与ABCG4 mRNA和蛋白表达的相关性。结果 ABCG4蛋白阳性主要定位于细胞膜和胞质,其在NSCLC组织中的阳性表达率为73.9%（68/92）,而在30例癌旁正常肺组织中几乎不表达。ABCG4蛋白在肺鳞癌和肺腺癌中的阳性表达率分别为67.3%和81.4％,差异无统计学意义（P＞0.05）。环磷酰胺、吉西他滨、多柔比星、紫杉醇和顺铂在NSCLC组织中的药物敏感程度与其相应组织中ABCG4蛋白阳性表达有关（rs均＞0.3,P均＜0.05）;除紫杉醇外,环磷酰胺、吉西他滨、多柔比星和顺铂在NSCLC组织中的药物敏感程度与其相应组织中ABCG4 mRNA表达量有关（P均＜0.05）。结论 ABCG4在肺鳞癌、肺腺癌中高表达,其表达程度与NSCLC部分化疗药物耐药有关,为进一步研究ABCG4在NSCLC中的表达及可能耐药机制提供实验依据。     

Mer receptor tyrosine kinase is frequently overexpressed in human non-small cell lung cancer,confirming resistance to erlotinib

Mer is a receptor tyrosine kinase (RTK) with oncogenic properties that is often overexpressed or activated in various malignancies. Using both immunohistochemistry and microarray analyses, we demonstrated that Mer was overexpressed in both tumoral and stromal compartments of about 70% of non-small cell lung cancer (NSCLC) samples relative to surrounding normal lung tissue. This was validated in freshly harvested NSCLC samples; however, no associations were found between Mer expression and patient features. Although Mer overexpression did not render normal lung epithelial cell tumorigenic in vivo, it promoted the in vitro cell proliferation, clonogenic colony formation and migration of normal lung epithelial cells as well as NSCLC cells primarily depending on MAPK and FAK signaling, respectively. Importantly, Mer overexpression induced resistance to erlotinib (EGFR inhibitor) in otherwise erlotinib-sensitive cells. Furthermore, Mer-specific inhibitor rendered erlotinib-resistant cells sensitive to erlotinib. We conclude that Mer enhances malignant phenotype and pharmacological inhibition of Mer overcomes resistance of NSCLC to EGFR-targeted agents.     

Overexpression of HE4 (human epididymis protein 4) enhances proliferation,invasion and metastasis of ovarian cancer

Overexpression of Human epididymis protein 4 (HE4) related with a role in ovarian cancer tumorigenesis while little is known about the molecular mechanism alteration by HE4 up regulation. Here we reported that overexpressed HE4 promoted ovarian cancer cells proliferation, invasion and metastasis. Furthermore, human whole genome gene expression profile microarrays revealed that 231 differentially expressed genes (DEGs) were altered in response to HE4, in which MAPK signaling, ECM receptor, cell cycle, steroid biosynthesis pathways were involved. The findings suggested that overexpressed HE4 played an important role in ovarian cancer progression and metastasis and that HE4 has the potential to serve as a novel therapeutic target for ovarian cancer.