Upregulation of LRIG1 suppresses malignant glioma cell growth by attenuating EGFR activity

Activated epidermal growth factor receptor (EGFR) has emerged as an important therapeutic target for a variety of solid tumors, particularly malignant gliomas. A recently discovered transmembrane glycoprotein, LRIG1, antagonizes the activity of epidermal growth factor receptor family receptor tyrosine kinases and acts as a negative feedback loop of EGFR and proposed tumor suppressors. The aim of this study was to investigate the impact of LRIG1 on the biological features of glioma cells and the possible mechanisms of enhanced apoptosis induced by upregulation of LRIG1. We observed that the expression of LRIG1 was decreased, while the expression of EGFR was increased in the majority of astrocytomas, and the ratio of EGFR/LRIG1 was increased by sixfold in tumors versus corresponding non-neoplastic tissue. Upregulation of LRIG1, followed by a decrease of EGFR on the cytomembrane of the cells, induced cell apoptosis and cell growth inhibition, and further reversed invasion in glioma cell lines and primary glioma cells. Our study now clearly indicates that LRIG1 indeed affects cell fate and biology behaviors of the cells in vitro by inhibiting phosphorylation of downstream MAPK and AKT signaling pathway, and the elevated release level of caspase-8 might contribute to the enhanced apoptosis in LRIG1 transfected glioma cells. Taken together, these findings provide us with an insight into LRIG1 function, and we conclude that LRIG1 evolved in gliomas as a rare feedback negative attenuator of EGFR and could offer a novel therapeutic target to treat patients with malignant gliomas. Fei Ye and Qinglei Gao contributed equally to this work.     

LRIG1 and the liar paradox in prostate cancer: a study of the expression and clinical significance of LRIG1 in prostate cancer

The course of prostate cancer varies greatly, and additional prognostic markers are needed. Leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1) is an endogenous inhibitor of growth factor signaling and a proposed tumor suppressor. Publicly available gene expression datasets indicate that LRIG1 may be overexpressed in prostate cancer. In our study, the expression of LRIG1 protein in prostate cancer was evaluated for the first time. Immunohistochemistry was performed on tissue microarrays from two different patient series: 355 Swedish patients diagnosed by transurethral resection and 293 American patients who underwent radical prostatectomy. In the Swedish series, high expression of LRIG1 correlated with Gleason score, T-stage, tumor cell proliferation, vascular density and epidermal growth factor receptor (EGFR) phosphorylation. Among the 256 Swedish patients, followed by watchful waiting, high LRIG1 expression was significantly associated with short overall and prostate cancer-specific survival. In contrast, in the US series, high LRIG1 expression was significantly associated with long overall survival. In vitro cell experiments showed that LRIG1 was induced by androgen stimulation, and its expression inhibited prostate cancer cell proliferation. Thus, LRIG1 expression was an independent marker for poor survival in the untreated patient series, perhaps as a secondary marker of androgen receptor and/or EGFR activation. On the contrary, LRIG1 was a marker for good prognosis after prostatectomy, which might be due to its growth inhibiting properties. We propose that LRIG1 is an important determinant of prostate cancer growth, and the implications of its expression on patient outcome depend on the clinical and biological circumstances.     

LRIG1 combined with cisplatin enhances bladder cancer lesions via a novel pathway

One aspect of chemotherapy insensitivity and resistance results from induction of epidermal growth factor receptor (EGFR) internalization and initial DNA damage repair in response to DNA-damaging stimuli, such as cisplatin (CDDP). Previously, we found that leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), as one of the natural ligands of EGFR, could combine with and down-regulate the expression of EGFR in bladder cancer cells. This finding interested us and we hypothesized that LRIG1 could be a novel candidate for facilitating cisplatin-induced bladder cancer cell lesions. To investigate this further, we overexpressed LRIG1 with an adenovirus vector in EJ/T24 bladder cancer cells and investigated total EGFR, nuclear expression of phosphorylated EGFR (pEGFR) and cell lesions with exposure to CDDP. CDDP-induced nuclear pEGFR levels accumulated with time and were decreased by LRIG1 overexpression. LRIG1-transduced cells treated with CDDP had more severe DNA damage, cellular apoptosis, growth inhibition and reversal of invasion. These preclinical studies indicate that LRIG1 may represent a new therapeutic approach to improve the response of bladder cancer to chemotherapy through a novel pathway.     

Downregulation of leucine‐rich repeats and immunoglobulin‐like domains 1 by microRNA‐20a modulates gastric cancer multidrug resistance

Multidrug resistance (MDR) significantly restricts the clinical efficacy of gastric cancer (GC) chemotherapy, and it is critical to search novel targets to predict and overcome MDR. Leucine‐rich repeats and immunoglobulin‐like domains 1 (LRIG1) has been proved to be correlated with drug resistance in several cancers. The present study revealed that LRIG1 was overexpressed in chemosensitive GC tissues and decreased expression of LRIG1 predicted poor survival in GC patients. We observed that upregulation of LRIG1 enhanced chemosensitivity in GC cells. Interestingly, miR‐20a, which was overexpressed in GC MDR cell lines and tissues, was identified to regulate LRIG1 expression by directly targeting its 3′ untranslated region. We also found that inhibition of miR‐20a suppressed GC MDR, and upregulation showed opposite effects. Moreover, we demonstrated that the miR‐20a/LRIG1 axis regulated GC cell MDR through epidermal growth factor receptor (EGFR)‐mediated PI3K/AKT and MAPK/ERK signaling pathways. Finally, LRIG1 expression in human GC tissues is inversely correlated with miR‐20a and EGFR. Taken together, the newly identified miR‐20a/LRIG1/EGFR link provides insight into the MDR process of GC, and targeting this axis represents a novel potential therapeutic strategy to block GC chemoresistance.     

LRIG1 and epidermal growth factor receptor in renal cell carcinoma: a quantitative RT--PCR and immunohistochemical analysis

In all, 31 renal cell carcinomas (RCCs) were examined for expression of the potential tumour suppressor LRIG1 (formerly Lig-1) and the epidermal growth factor receptor (EGFR). Eight matched samples of uninvolved kidney cortex were also evaluated. Gene expression was examined by quantitative real-time RT-PCR. In the eight matched sample pairs (uninvolved kidney cortex and tumour), protein expression was examined by immunohistochemistry. Conventional (clear cell) tumours showed an expected upregulation of EGFR. LRIG1 expression was generally downregulated in conventional and papillary RCC but not in chromophobic RCC. The ratio between EGFR and LRIG1 was more than 2.5-fold higher in the eight tumours compared with matched uninvolved kidney cortex and was at least two-fold higher than the mean normal ratio in 21 of 31 samples analysed. The observed downregulation of LRIG1 and increased EGFR/LRIG1 ratios are consistent with LRIG1 being a suppressor of oncogenesis in RCC by counteracting the tumour-promoting properties of EGFR. Further studies are justified to elucidate the explicit role of LRIG1 in the oncogenesis of RCC.     

Oestrogen and vitamin D receptor (VDR) genotypes and the expression of ErbB-2 and EGF receptor in human rectal cancers

Oestrogen/oestrogen receptor (ER) and vitamin D/vitamin D receptor (VDR) systems have been implicated in the pathogenesis of colorectal cancers. The expression of erbB-2 and epidermal growth factor receptor (EGFR) in colorectal cancers has been suggested to have diagnostic and prognostic significance. In our study, XbaI and PvuII polymorphisms of the ER gene and the BsmI polymorphism of the VDR gene were studied in 56 Caucasian patients with rectal cancer. The relationship between the ER and VDR genotypes and the expression of oncogenes was also investigated. The presence of the x allele of ER gene significantly correlated with the overexpression of the erbB-2 and EGFR oncogenes. Significantly increased erbB-2 expression was observed in patients with the VDR B allele. The XXbb allelic combination of the ER/VDR genes was associated with a significantly lower erbB-2 expression, whereas in the other genotypes significantly higher oncogene expression was seen. Our data raise the possibility that ER/VDR gene polymorphisms accompanied by variable oncogene expression might influence the pathogenetic processes of colorectal cancers.     

Transcripts for transforming growth factors in human breast cancer: clinical correlates

The levels of mRNA for transforming growth factors (TGF alpha and beta) and the epidermal growth factor receptor (EGFR) were determined in 69 human breast carcinomas and 20 biopsies of non-neoplastic breast tissue by dot blot hybridisation analysis. TGF alpha mRNA was detected in 42% of cancers and 44% of non-neoplastic breast tissue at low levels. TGF beta mRNA was found in all breast cancers and non-neoplastic breast tissues, but the levels of TGF beta mRNA were found to be higher in breast cancers (P = 0.01). EGFR mRNA was detected in 55% of breast cancers and in all non-neoplastic breast tissue tested. The presence of EGFR mRNA was inversely related to oestrogen receptor (ER) status (P = 0.0001). Coexpression of TGF alpha and EGFR was observed in 28% of the carcinomas, and significantly more commonly in ER negative tumours (P = 0.01). No significant relationship was found between histological grade, tumour cellularity or tumour desmoplasia and expression of either the TGFs or of EGFR mRNA. High levels of TGF beta were, however, associated with the absence of lymph node metastases at presentation (P = 0.05). Levels of TGF alpha and beta and EGFR mRNA were analysed in relationship to the relapse-free and overall survival of patients with breast cancer, but none was found to predict significantly the outcome in these patients. Longer clinical follow-up and larger numbers of patients are required to determine whether TGFs will prove a useful marker for prognosis in breast cancer patients.     

Restoration of LRIG1 suppresses bladder cancer cell growth by directly targeting EGFR activity

Background

Recently, leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), a negative regulator of EGFR, was discovered is a novel agent for suppressing bladder cancer. The aim of this study was to investigate the impact of LRIG1 on the biological features of aggressive bladder cancer cells and the possible mechanisms of enhanced apoptosis induced by upregulation of LRIG1.

Methods

In this study, we examined the mRNA and protein expression of LRIG1 and EGFR in bladder cancers and normal bladder. Meanwhile, we overexpressed LRIG1 with adenovirus vector in T24/5637 bladder cancer cell lines, and we used real time-PCR, western blot, and co-immunoprecipitation analysis in order to examine the effects of LRIG1 gene on EGFR. Furthermore, we evaluate the impact of LRIG1 gene on the function of human bladder cancer cells and EGFR signaling.

Results

The expression of LRIG1 was decreased, while the expression of EGFR was increased in the majority of bladder cancer, and the ratio of EGFR/LRIG1 was increased in tumors versus normal tissue. We found that upregulation of LRIG1 induced cell apoptosis and cell growth inhibition, and further reversed invasion in bladder cancer cell lines in vitro by inhibiting phosphorylation of downstream MAPK and AKT signaling pathway.

Conclusion

Taken together, our findings provide us with an insight into LRIG1 function, and we conclude that LRIG1 evolved in bladder cancer as a rare feedback negative attenuator of EGFR, thus could offer a novel therapeutic target to treat patients with bladder cancer.

     

长链非编码RNACASC9在结直肠癌组织中的表达及其临床意义

目的：探讨长链非编码RNA癌症易感性候选基因9(lncRNA CASC9)在结直肠癌组织中的表达及其临床意义。方法：收集结直肠癌患者癌组织和癌旁组织87例,采用实时荧光定量PCR (qPCR)法检测lncRNA CASC9的表达情况,分析lncRNA CASC9在结直肠癌组织和相应癌旁组织中的表达水平及其与临床病理指标的相关性,采用Kaplan-Meier法进行生存分析,Log-rank法检验lncRNA CASC9表达量与结直肠癌患者临床预后的关系。结果：lncRNA CASC9在结直肠癌组织较癌旁组织中表达明显升高(P<0.01)。结直肠癌组织中lncRNA CASC9的表达水平与癌组织的不同分化程度(χ²=6.877,P=0.032)、TNM分期(χ²=7.660,P=0.022)以及是否发生淋巴结转移(χ²=9.901,P=0.002)相关,而与性别、年龄、肿瘤直径、肿瘤位置均无明显相关关系(均为P>0.05)。Kaplan-Meier生存分析发现,lncRNA CASC9高表达患者总生存期和无进展生存时间均较lncRNA CASC9低表达患者明显缩短(χ²=17.91,P<0.01;χ²=11.23,P=0.001)。结论：lncRNA CASC9在结直肠癌组织中的表达明显升高,与结直肠癌的分化程度、TNM分期、淋巴结转移有关,其有可能成为判断结直肠癌患者预后的潜在生物标志物。     

多亮氨酸重复区免疫球蛋白样蛋白1及表皮生长因子受体在子宫颈腺癌组织中的表达及其意义

目的 研究多亮氨酸重复区免疫球蛋白样蛋白1（LRIGl）及表皮生长因子受体（EGFR）在子宫颈腺癌中的表达,并探讨LRIG1与预后的关系.方法 采用免疫组织化学法检测子宫颈腺癌47例、子宫颈腺上皮内瘤变（CGIN） 24例和正常子宫颈组织60例中LRIG1及EGFR的表达情况,并对二者相关性进行分析.结果 LRIG1蛋白在子宫颈腺癌组织、CGIN、正常子宫颈组织的阳性表达率分别为21.28 ％（10/47）、29.17％（7/24）和83.33％（50/60）,差异有统计学意义（P＜0.05）;EGFR蛋白在子宫颈腺癌组织、CGIN、正常子宫颈组织的阳性表达率分别为82.98％（39/47）、45.83％（11/24）、5.00％（3/60）.不同年龄分层患者LRIG1的阳性表达率差异无统计学意义（P＞0.05）,而不同组织学分级、淋巴结转移及临床分期分层间,LRIG1的阳性表达率差异均有统计学意义（均P＜ 0.05）.LRIG1蛋白阳性表达患者生存率高于阴性表达者,差异有统计学意义（P＜0.05）.结论 LRIG1可能作为子宫颈腺癌的预后因素之一,对子宫颈腺癌的临床转归具有一定预测意义,其机制可能与抑制EGFR的信号转导有关.     

The transmembrane protein LRIG1 triggers melanocytic tumor development following chemically induced skin carcinogenesis

The incidence of melanoma and nonmelanoma skin cancer has increased tremendously in recent years. Although novel treatment options have significantly improved patient outcomes, the prognosis for most patients with an advanced disease remains dismal. It is, thus, imperative to understand the molecular mechanisms involved in skin carcinogenesis in order to develop new targeted treatment strategies. Receptor tyrosine kinases (RTK) like the ERBB receptor family, including EGFR/ERBB1, ERBB2/NEU, ERBB3, and ERBB4, are important regulators of skin homeostasis and their dysregulation often results in cancer, which makes them attractive therapeutic targets. Members of the leucine‐rich repeats and immunoglobulin‐like domains protein family (LRIG1‐3) are ERBB regulators and thus potential therapeutic targets to manipulate ERBB receptors. Here, we analyzed the function of LRIG1 during chemically induced skin carcinogenesis in transgenic mice expressing LRIG1 in the skin under the control of the keratin 5 promoter (LRIG1‐TG mice). We observed a significant induction of melanocytic tumor formation in LRIG1‐TG mice and no difference in papilloma incidence between LRIG1‐TG and control mice. Our findings also revealed that LRIG1 affects ERBB signaling via decreased phosphorylation of EGFR and increased activation of the oncoprotein ERBB2 during skin carcinogenesis. The epidermal proliferation rate was significantly decreased during epidermal tumorigenesis under LRIG1 overexpression, and the apoptosis marker cleaved caspase 3 was significantly activated in the epidermis of transgenic LRIG1 mice. Additionally, we detected LRIG1 expression in human cutaneous squamous cell carcinoma and melanoma samples. Therefore, we depleted LRIG1 in human melanoma cells (A375) by CRISPR/Cas9 technology and found that this caused EGFR and ERBB3 downregulation in A375 LRIG1 knockout cells 6 h following stimulation with EGF. In conclusion, our study demonstrated that LRIG1‐TG mice develop melanocytic skin tumors during chemical skin carcinogenesis and a deletion of LRIG1 in human melanoma cells reduces EGFR and ERBB3 expression after EGF stimulation.     

A soluble ectodomain of LRIG1 inhibits cancer cell growth by attenuating basal and ligand-dependent EGFR activity

Leucine-rich repeats and immunoglobulin-like domains-1 (LRIG1) is a transmembrane protein with an ectodomain containing 15 leucine-rich repeats (LRRs) homologous to mammalian decorin and the Drosophila kekkon1 gene. In this study, we demonstrate that a soluble ectodomain of LRIG1, containing only the LRRs, inhibits ligand-independent epidermal growth factor receptor (EGFR) activation and causes growth inhibition of A431, HeLa and MDA-468 carcinoma cells. In contrast, cells that do not express detectable levels of EGFR fail to respond to soluble LRIG1. However, when a functional EGFR gene is introduced in these cells, they become growth-inhibited by soluble LRIG1 protein. Furthermore, we demonstrate the existence of high-affinity (K(d)=10 nM) binding sites on the A431 cells that can be competitively displaced (up to 75%) by molar excess of EGF. Even more powerful effects are obtained with a chimeric proteoglycan harboring the N-terminus of decorin, substituted with a single glycosaminoglycan chain, fused to the LRIG1 ectodomain. Both proteins also inhibit ligand-dependent activation of the EGFR and extracellular signal-regulated protein kinase 1/2 signaling in a rapid and dose-dependent manner. These results suggest a novel mechanism of action evoked by a soluble ectodomain of LRIG1 protein that could modulate EGFR signaling and its growth-promoting activity. Attenuation of EGFR activity without physical downregulation of the receptor could represent a novel therapeutic approach toward malignancies in which EGFR plays a primary role in tumor growth and survival.     

Potential for clinical radionuclide-based imaging and therapy of common cancers expressing EGFR-family receptors

High expression of epidermal growth factor receptor (EGFR)-family receptors, especially EGFR, HER2, and HER3, makes them interesting for targeted radionuclide-based imaging and therapy of disseminated cancer. The expression in some commonly occurring cancers such as breast, prostate, colorectal, and urinary bladder cancers is summarized. Possible strategies for radionuclide-based imaging and therapy are briefly discussed, especially in relation to the receptor expression in metastases.     

EGFR,HER2和HER3在胆管癌中的表达及预后价值

目的 观察表皮生长因子受体(Epidermal growth factor receptor,EGFR)、表皮生长因子受体2(Human epidermal growth factor receptor 2,HER2)和表皮生长因子受体3(Human epidermal growth factor receptor 3,HER3)在胆管癌(Cholangiocarcinoma,CCA)组织中的表达情况,探讨其与CCA患者临床病理特征、总生存期和CCA细胞增殖的关系。方法 收集2009年1月—2013年10月于我院手术的CCA患者50例,并同时收取癌旁组织作为对照。采用免疫组织化学方法及RT-PCR方法检测CCA及癌旁组织中EGFR、HER2和HER3表达情况。收集患者临床病理参数,分析EGFR、HER2和HER3表达与CCA临床病理参数之间的关系。绘制Kaplan-Meier生存曲线,采用Log-rank检验和Cox比例风险模型分析EGFR、HER2和HER3表达情况与50例CCA患者术后总生存期之间的关系。采用RNA干扰方法敲低CCA细胞株QBC939中EGFR、HER2和HER3表达,Western blot检测EGFR、HER2和HER3敲低效果,MTT方法检测EGFR、HER2和HER3对QBC939细胞增殖的影响。结果 CCA组织中可检测到EGFR、HER2和HER3的阳性表达。临床病理特征关系分析结果显示,HER2表达与CCA淋巴结转移相关(P＜0.05);而EGFR和HER3除与CCA淋巴结转移相关外,还与肿瘤分化程度相关(P＜0.05)。EGFR、HER2和HER3阳性患者术后总生存期明显低于阴性患者(P＜0.05)。敲低CCA QBC939细胞中EGFR、HER2和HER3表达后,QBC939细胞增殖能力显著降低(P＜0.05)。结论 CCA组织中EGFR、HER2和HER3表达与患者总生存期密切相关,机制可能与促进CCA细胞的增殖相关。     

Involvement of nuclear NHERF1 in colorectal cancer progression

NHERF1 (Na+/H+ exchanger regulatory factor?1) is expressed in the luminal membrane of many epithelia, and associated with proteins involved in tumor progression. Alterations of NHERF1 expression in different sites of metastatic colorectal cancer (mCRC) suggest a dynamic role of this protein in colon carcinogenesis. We focused on the observation of the altered expression of NHERF1 from non-neoplastic tissues to metastatic sites by immunohistochemistry. Moreover, we studied, by immunofluorescence, the colocalization between NHERF1 and the epidermal growth factor receptor (EGFR), whose overexpression is implicated in CRC progression. NHERF1 showed a different localization and expression in the examined sites. The distant non-neoplastic tissues showed NHERF1 mostly expressed at the apical membrane, while in surrounding non-neoplastic tissue decreased the apical membrane and increased cytoplasmic immunoreactivity. In adenomas a shift from apical membrane to cytoplasmic localization and nuclear expression were observed. Cytoplasmic staining in the tumor, and metastatic sites was stronger than surrounding non-neoplastic tissue. Furthermore, nuclear NHERF1 expression was noted in 80% of all samples and surprisingly, it appeared already in adenoma lesions, suggesting that NHERF1 represents an early marker of pre-morphological triggering of colorectal carcinogenesis. Then, in few tumors a positive direct correlation between membrane NHERF1 and EGFR expression was evidenced by their colocalization. Nuclear NHERF1 expression, present in the early stages of carcinogenesis and related with poor prognosis, may contribute to the onset of malignant phenotype. Specifically, we hypothesize the direct involvement of nuclear NHERF1 in both carcinogenesis and progression and its role as a potential colorectal cancer marker.     

EGFR and cancer prognosis

Elevated levels of the epidermal growth factor receptor (EGFR), a growth-factor-receptor tyrosine kinase, and/or its cognate ligands have been identified as a common component of multiple cancer types and appear to promote solid tumour growth. This article examines the relationship between EGFR expression and cancer prognosis based on literature compiled on PubMed between 1985 and September 2000. More than 200 studies were identified that analysed relapse-free-interval or survival data directly in relation to EGFR levels in over 20000 patients. Analysis of the data showed that 10 cancer types both express elevated levels of EGFR relative to normal tissues and have been studied in sufficient depth to allow sound judgements to be made concerning the association between EGFR and patient outlook. The EGFR was found to act as a strong prognostic indicator in head and neck, ovarian, cervical, bladder and oesophageal cancers. In these cancers, increased EGFR expression was associated with reduced recurrence-free or overall survival rates in 70% (52/74) of studies. In gastric, breast, endometrial and colorectal cancers, the EGFR provided more modest prognostic information, correlating to poor survival rates in 52% (13/25) of studies, while in non-small cell lung cancer (NSCLC), EGFR expression only rarely (3/10 studies) related to patient outlook. However, it is likely that the true prognostic significance of the EGFR has been underestimated as the published studies only assessed total cellular EGFR levels, rather than the activated form of the receptor, and were not standardised with regard to patient populations or assay methods. Finally, it is important to stress that failure to detect a prognostic significance for EGFR in any one cancer type does not necessarily preclude patients from benefiting from anti-EGFR therapies.     

大肠癌细胞FoxQ1与EGFR基因表达的相关性

目的 探讨大肠癌细胞中FoxQ1与EGFR基因间的相关性,为研究大肠癌中FoxQ1基因在EGFR通路中的作用机制奠定基础。 方法 应用荧光定量PCR以293-T细胞中FoxQ1及EGFR基因相对表达量为1作为参照,检测大肠癌细胞系DLD1、HT29、LOVO、HCT116中FoxQ1及EGFR基因mRNA相对表达量;荧光定量检测经shRNA-FoxQ1慢病毒干扰后的DLD1细胞（命名为DLD1-shRNAFoxQ1）中EGFR的相对表达量改变;DLD1-shRNA-FoxQ1经EGFR酪氨酸激酶抑制剂Erlotinib HCl和siRNA-EGFR处理后,荧光定量PCR分别检测FoxQ1和EGFR基因mRNA相对表达量。结果 （1）FoxQ1在DLD1、HT29、LOVO、HCT116细胞系中的相对表达量分别为83.09、59.58、0.06、0.03,EGFR的相对表达量分别为4.95、3.67、2.08、1.36;（2）经shRNA-FoxQ1干扰的DLD1 细胞EGFR表达量随FoxQ1表达量的降低而增高;（3）细胞DLD1-shRNA-FoxQ1、DLD1-shRNA-Control分别经 siRNA-EGFR处理抑制EGFR的表达后,FoxQ1表达量随EGFR表达量的降低而增高,经Erlotinib HCl阻断EGFR酪氨酸激酶后,FoxQ1表达量增高。结论 大肠癌细胞系中FoxQ1与EGFR基因的表达趋势基本一致;同时两者间可能相互存在负反馈调节机制,从而维持大肠癌细胞中FoxQ1与EGFR高表达的状态。     

lncRNA BLACAT1靶向LEMD1促进结直肠癌细胞的增殖和转移

目的 研究长链非编码RNA(lncRNA)BLACAT1在结直肠癌细胞发生发展过程的作用机制。方法 starBase分析TCGA数据库中lncRNA BLACAT1分别在结直肠癌组织和癌旁组织中的表达水平,采用qPCR分别检测10例结直肠癌患者癌组织和癌旁组织中lncRNA BLACAT1的表达水平;检测结直肠癌细胞系SW620、SW480、HT-29、LoVo、HCT116和正常结直肠上皮细胞FHC中lncRNA BLACAT1的mRNA表达水平,筛选lncRNA BLACAT1高表达细胞系;敲低lncRNA BLACAT1验证对高表达细胞系增殖、迁移和侵袭的影响;starBase在线预测与lncRNA BLACAT1靶向作用的基因,qPCR和Western blot实验验证结果;starBase分析lncRNA BLACAT1与作用基因相关性,双荧光素酶报告基因实验验证lncRNA BLACAT1的靶基因;检测lncRNA BLACAT1作用靶基因对结直肠癌细胞的增殖、迁移和侵袭的影响。结果 TCGA数据库分析和结直肠癌患者检测结果均表明癌组织中lncRNA BLACAT1表达明显高于癌旁组织(P＜0.001);结直肠癌细胞系SW620中lncRNA BLACAT1的mRNA表达水平最高(P＜0.001);敲低lncRNA BLACAT1能够抑制SW620细胞的增殖(P＜0.001)、迁移(P＜0.001)和侵袭能力(P＜0.001);qPCR和Western blot实验及数据库分析结果表明lncRNA BLACAT1与LEMD1的表达存在正相关关系(r=0.778,P＜0.001),双荧光素酶报告基因实验证明LEMD1是lncRNA BLACAT1的靶基因;lncRNA BLACAT1上调LEMD1的表达,促进SW620细胞的增殖(P＜0.001)、迁移(P＜0.001)和侵袭(P＜0.001)。结论 lncRNA BLACAT1靶向LEMD1促进结直肠癌细胞SW620的增殖和转移。     

Molecular alterations in tumors and response to combination chemotherapy with gefitinib for advanced colorectal cancer.

PURPOSE: Recently, activating mutations of the epidermal growth factor receptor (EGFR) gene were discovered in non-small cell lung cancers sensitive to gefitinib (ZD1839, an EGFR tyrosine kinase inhibitor) but not in gefitinib-resistant cancers. Abnormalities of EGFR and related pathways may have an effect on responsiveness of advanced colorectal cancer to combination chemotherapy with gefitinib. EXPERIMENTAL DESIGN: We examined patients with previously untreated metastatic colorectal cancer, who were enrolled into two phase I/II trials of combination chemotherapy (irinotecan, leucovorin, and 5-fluorouracil) and daily oral gefitinib. We obtained paraffin tissue blocks of primary tumors from 31 patients, sequenced the EGFR, KRAS, and BRAF genes, and did immunohistochemistry for EGFR, phosphorylated AKT1, p53, p21, and p27. RESULTS: Twelve (39%) of the 31 patients experienced a partial objective response to the therapy. A novel EGFR mutation in exon 18 (c.2170G>A, p.Gly724Ser) was identified in only one patient who did not experience an objective tumor response. EGFR immunohistochemistry was not predictive of responsiveness. In contrast, loss of p21 was associated with a higher response rate to therapy (P = 0.05). Moreover, the response rate among patients whose tumors maintained p21 expression and possessed a mutation in p53 was only 9% (1 of 11, P = 0.005). Overexpression of phosphorylated AKT1 also seemed to predict a trend towards resistance to the therapy. CONCLUSIONS: p21 expression in colorectal cancer, especially in combination with p53 mutation, is a predictor of resistance to the combination chemotherapy with gefitinib. Activating EGFR mutations are rare in colorectal cancer and do not seem to confer sensitivity to gefitinib and chemotherapy.     

Inhibition of LRIG3 gene expression via RNA interference modulates the proliferation,cell cycle,cell apoptosis,adhesion and invasion of glioblastoma cell (GL15)

LRIG3 (leucine-rich repeats and immunoglobulin-like domains, LRIG) gene is both under-and over-expressed in human cancers and its role on tumor growth is not fully clarified. Here, we used a human U6 promoter-driven DNA template approach to induce short hairpin RNA (shRNA)-triggered RNA interference (RNAi) to block LRIG3 gene expression in the human glioma cell line GL15. Specific knockdown of LRIG3 by shRNA resulted in significantly increase of the GL15 invasion and adhesion activity in vitro and markedly promoted cell growth. LRIG3 repression also induced increment of the proportion of G0/G1 cells and inhibited apoptosis in GL15 cells. Our results demonstrated that RNAi against LRIG3 could effectively down regulate LRIG3 gene expression. LRIG3 might be involved in the regulation of EGFR signaling, and serve as a tumor suppressor gene in the pathogenesis of glioma.