HRD1 suppresses the growth and metastasis of breast cancer cells by promoting IGF-1R degradation

HRD1 (3-hydroxy-3-methylglutaryl reductase degradation) is an E3 ubiquitin ligase. We found that HRD1 was significantly downregulated in 170 breast cancer tissues. Low tumoral HRD1 expression was correlated with clinicopathological characteristics and a shorter survival in breast cancer patients. P65 specifically bound to the HRD1 promoter and inhibited HRD1 expression. Suppression of NF-κB activity reversed IL-6-induced downregulation of HRD1 expression. HRD1 interacted with IGF-1R and promoted its ubiquitination and degradation by the proteasome. Overexpression of HRD1 resulted in the inhibition of growth, migration and invasion of breast cancer cells in vitro and in vivo. Furthermore, HRD1 attenuated IL-6-induced epithelial-mesenchymal transition in MCF10A cells. These findings uncover a novel role for HRD1 in breast cancer.     

乳腺癌中ＢＲＣＡ-１和ＩＧＦ-１Ｒ的研究进展

乳腺癌是女性最常见的恶性肿瘤之一,多年的研究表明乳腺癌属全身性疾病,其发生、发展是一系列因素共同作用的结果。ＢＲＣＡ-１是一种人乳腺癌易感基因,其结构、功能异常与乳腺癌的发生发展有十分密切的联系。胰岛素样生长因子 １受体（ＩＧＦ-１Ｒ）作为酪氨酸蛋白激酶类受体家族的主要成员之一,是目前临床乳腺癌诊断和判断预后的一个重要指标。本文通过介绍ＢＲＣＡ-１和ＩＧＦ-１Ｒ在乳腺癌中的研究进展,探讨其在乳腺癌发生、发展方面的作用,为其在临床上的应用提供理论依据。     

IGF-1R pathway activation as putative biomarker for linsitinib therapy to revert tamoxifen resistance in ER-positive breast cancer

Preclinical studies indicate that activated IGF-1R can drive endocrine resistance in ER-positive (ER+) breast cancer, but its clinical relevance is unknown. We studied the effect of IGF-1R signaling on tamoxifen benefit in patients and we searched for approaches to overcome IGF-1R-mediated tamoxifen failure in cell lines. Primary tumor blocks from postmenopausal ER+ breast cancer patients randomized between adjuvant tamoxifen versus nil were recollected. Immunohistochemistry for IGF-1R, p-IGF-1R/InsR, p-ERα(Ser118), p-ERα(Ser167) and PI3K/MAPK pathway proteins was performed. Multivariate Cox models were employed to assess tamoxifen efficacy. The association between p-IGF-1R/InsR and PI3K/MAPK pathway activation in MCF-7 and T47D cells was analyzed with Western blots. Cell proliferation experiments were performed under various growth-stimulating and -inhibiting conditions. Patients with ER+, IGF-1R-positive breast cancer without p-IGF-1R/InsR staining (n = 242) had tamoxifen benefit (HR 0.41, p = 0.0038), while the results for p-IGF-1R/InsR-positive patients (n = 125) were not significant (HR 0.95, p = 0.3). High p-ERα(Ser118) or p-ERα(Ser167) expression was associated with less tamoxifen benefit. In MCF-7 cells, IGF-1R stimulation increased phosphorylation of PI3K/MAPK proteins and ERα(Ser167) regardless of IGF-1R overexpression. This could be abrogated by the dual IGF-1R/InsR inhibitor linsitinib, but not by the IGF-IR-selective antibody 1H7. In MCF-7 and T47D cells, stimulation of the IGF-1R/InsR pathway resulted in cell proliferation regardless of tamoxifen. Abrogation of cell growth was regained by addition of linsitinib. In conclusion, p-IGF-1R/InsR positivity in ER+ breast cancer is associated with reduced benefit from adjuvant tamoxifen in postmenopausal patients. In cell lines, stimulation rather than overexpression of IGF-1R is driving tamoxifen resistance to be abrogated by linsitinib.     

POR overexpression induces tamoxifen-resistance in breast cancer through the STAT1/c-Myc pathway

Breast cancer is the most common cancer in women worldwide. Although tamoxifen (TAM), a selective estrogen receptor (ER) modulator, is widely used to treat ER-positive breast cancers, resistance to TAM remains a major clinical problem. NADPH-dependent cytochrome P450 reductase (POR) is known to participate in drug metabolism and steroid metabolism. Recent studies showed that high POR expression was correlated with poor outcomes in triple-negative breast cancer (TNBC), and POR might be a prognostic biomarker in TNBC. However, the role of POR in TAM resistance is still elusive. In this study, we found that high POR expression was associated with poor prognosis of ER-positive and TAM-treated breast cancer patients. In addition, COX analysis showed that POR expression was an independent prognostic biomarker for ER-positive as well as TAM-treated breast cancer patients. Furthermore, our results suggested that POR overexpression promoted TAM resistance by activating the STAT1/c-Myc pathway in ER-positive breast cancer cells. Immunohistochemical analysis showed that high POR/STAT1 expression was correlated with poor prognosis in TAM-treated breast cancer patients. Notably, combined treatment with TAM and a specific STAT1 inhibitor Fludarabine was more effective for inhibiting TAM-resistant breast cancer cells. Altogether, our findings suggested that POR overexpression induced TAM resistance through STAT1/c-Myc pathway and might serve as an independent prognostic biomarker in TAM-treated breast cancer patients. Combining TAM and STAT1 inhibitors might be an effective strategy for treating POR-induced TAM-resistant breast cancer.     

circRNA_001569通过miR-145/HBXIP轴影响乳腺癌细胞的恶性生物学行为

目的：探讨 circRNA_001569 通过 miR-145/HBXIP 轴在乳腺癌细胞增殖、侵袭、迁移中发挥的作用。方法:收集2016年1月至2019年1月期间衡水市人民医院收治的30例乳腺癌患者的癌组织和癌旁组织。qPCR检测circRNA_001569在乳腺癌组织、癌旁组织以及细胞系中的表达。生物信息学工具预测miR-145的靶基因,RNA免疫沉淀（RNA immunoprecipitation,RIP）和双荧光素酶报告基因实验检测 miR-145 或靶基因之间的相互作用 ;向乳 腺 癌 MDA-MB-231 和 MCF-7细胞中转染si-circRNA_001569、miR-145 mimics或miR-145 inhibitor,建立基因过表达或沉默的细胞模型,qPCR和Western blotting分别检测转染对相关基因和蛋白表达的影响,CCK-8法、Transwell实验检测转染对细胞增殖、侵袭和迁移的影响。结果:在乳腺癌组织和乳腺癌细胞中,circRNA_001569 和 HBXIP 均呈高表达、miR-145 呈低表达。RIP 分析和双荧光素酶实验证实了 miR-145 与circRNA_001569和HBXIP之间的靶向关系;circRNA_001569或HBXIP过表达促进MDA-MB-231和MCF-7细胞的增殖、侵袭和迁移（均 P<0.01）,而 miR-145 过表达起相反的作用（均 P<0.01）。结论:circRNA_001569 可能通过下调 miR-145 的表达、上调HBXIP的表达从而促进乳腺癌细胞的增殖、侵袭和迁移。     

IGF-1R基因在伴或不伴糖尿病的乳腺癌组织中的表达及其相关因素

目的:检测IGF-1R基因在伴或不伴糖尿病的乳腺癌组织中的表达,并探讨其与乳腺癌临床病理因素的关系。方法:利用免疫组织化学SP法检测68例不伴糖尿病的乳腺癌组织及相应的癌旁组织中IGF-1R蛋白的表达情况,与34例伴糖尿病的乳腺癌组织及相应的癌旁组织中IGF-1R蛋白的表达情况,并分析其与病人年龄、TNM分期、肿瘤大小及淋巴结转移等临床病理特征之间的相关性。结果:伴或不伴糖尿病的乳腺癌组织中IGF-1R蛋白的表达水平明显高于其相应的癌旁组织(P＜0.05)。伴或不伴糖尿病的乳腺癌组织中IGF-1R的表达与肿瘤的大小及TNM分期有关(P＜0.05),而与患者年龄无关。不伴糖尿病的乳腺癌组织中IGF-1R的表达与患者淋巴结转移状态有关(P＜0.05),而伴糖尿病的乳腺癌组织中IGF-1R的表达与患者淋巴结转移状态无关(P＞0.05)。结论:IGF-1R基因在乳腺癌组织中的表达显著上调;IGF-1R基因的表达与肿瘤大小、TNM分期有关,而与年龄无关。不伴糖尿病的乳腺癌组织中IGF-1R的表达与患者淋巴结转移状态有关,而伴糖尿病的乳腺癌组织中IGF-1R的表达与患者淋巴结转移状态无关。     

Fibroblast growth factor-2, derived from cancer-associated fibroblasts,stimulates growth and progression of human breast cancer cells via FGFR1 signaling

Cancer-associated fibroblasts (CAFs) constitute a major compartment of the tumor microenvironment. In the present study, we investigated the role for CAFs in breast cancer progression and underlying molecular mechanisms. Human breast cancer MDA-MB-231 cells treated with the CAF-conditioned media manifested a more proliferative phenotype, as evidenced by enhanced messenger RNA (mRNA) expression of Cyclin D1, c-Myc, and proliferating cell nuclear antigen. Analysis of data from The Cancer Genome Atlas revealed that fibroblast growth factor-2 (FGF2) expression was well correlated with the presence of CAFs. We noticed that the mRNA level of FGF2 in CAFs was higher than that in normal fibroblasts. FGF2 exerts its biological effects through interaction with FGF receptor 1 (FGFR1). In the breast cancer tissue array, 42% estrogen receptor-negative patients coexpressed FGF2 and FGFR1, whereas only 19% estrogen receptor-positive patients exhibited coexpression. CAF-stimulated MDA-MB-231 cell migration and invasiveness were abolished when FGF2-neutralizing antibody was added to the conditioned media of CAFs. In a xenograft mouse model, coinjection of MDA-MB-231 cells with activated fibroblasts expressing FGF2 dramatically enhanced tumor growth, and this was abrogated by silencing of FGFR1 in cancer cells. In addition, treatment of MDA-MB-231 cells with FGF2 enhanced expression of Cyclin D1, a key molecule involved in cell cycle progression. FGF2-induced cell migration and upregulation of Cyclin D1 were abolished by siRNA-mediated FGFR1 silencing. Taken together, the above findings suggest that CAFs promote growth, migration and invasion of MDA-MB-231 cells via the paracrine FGF2-FGFR1 loop in the breast tumor microenvironment.     

Prognostic significance of IGF-1R expression in patients treated with breast-conserving surgery and radiation therapy

Background

Insulin-like growth factor (IGF) receptor is a key receptor in apoptotic protection, cell adhesion, longevity, and transformation into a cancerous cell and can induce malignant changes in the presence of the IGF ligand. Over-expression of IGF-1R has been associated with resistance to radiation. Inhibitors of IGF-1R have been shown to enhance tumor radiation sensitivity and amplify radiation therapy-induced apoptosis. The purpose of this study is to evaluate the prognostic significance of IGF-1R expression in patients with breast cancer treated with breast conserving therapy.

Materials and methods

Paraffin specimens from 345 women with early stage breast cancer treated with BCT were constructed into tissue microarrays and stained for IGF-1R, COX-2 and p53. The molecular profiles were correlated with clinical-pathologic factors, overall, local, and distant relapse-free survival. The association between IGF-1R, other co-variables, and outcome was assessed.

Results

IGF-1R over-expression was identified in 197 cases (57%). IGF-1R over-expression was found to be correlated with African-American race (p = 0.0233), p53 status (p = 0.0082) and COX-2 expression (p < 0.0001). While IGF-1R over-expression was associated with lower overall survival (p = 0.0224) in node-negative patients, there was no impact of IGF-1R expression on local control.

Conclusions

In node-negative patients, patients with high levels of IGF-1R were found to have a significant reduction in overall survival, but no apparent effect on local control. Given the limited published data on IGF-1R in early stage, conservatively treated patients, further studies investigating IGF-1R expression in this cohort are necessary.     

Dual targeting of IGF-1R and PDGFR inhibits proliferation in high-grade gliomas cells and induces radiosensitivity in JNK-1 expressing cells

Increased expression and activation of receptor tyrosine kinases frequently occur in human brain tumors, mediating a variety of growth-promoting pathways and leading to radioresistance; however, little is known about their motogenic potency relative to one another. In this study, we found co-expression of Insulin like growth factor-1 receptor (IGF-1R) and platelet derived growth factor receptor (PDGFR) in two high-grade gliomas (HGG) cell lines 18 and 38. Dual targeting of IGF-1R and PDGFR increased cell death in both 18 and 38 cell lines in comparison to inhibition of either receptor alone. In addition, co-inhibition of IGF-1R and PDGFR increased radiosensitivity in 18 cells but failed to intensify the effect of radiation in 38 cells. In HGG cells, radiation-induced cell death has been connected to the activation of c-Jun-NH2-terminal kinase-1 (JNK1). We found that JNK1 was weakly expressed in 38 cells while it had an elevated expression in 18 cells. Exposure to ionizing radiation induced JNK1 activation only in 18 cells without affecting the protein activity in 38 cells. These results suggest that in 18 cell line radiation-activated JNK1 may provide an anti-proliferative signaling, parallel to receptors co-targeting. To test this hypothesis, HGG cells were treated with dominant negative JNK1 (dnJNK1) and the response to radiation was assayed in presence or absence of receptors co-inhibition. Indeed dnJNK protected 18 cells against γ-irradiation-induced cell death. dnJNK treatment did not influence radiation response of the 38 cell line, which expressed low levels of JNK1. In conclusion we found that IGF-1R and PDGFR co-inhibition caused an increased cell death in two HGG cell line and induced the radiosensitization of the JNK1 expressing cell line.     

CAFs对乳腺癌细胞生物学特性的影响及机制探讨

目的：通过乳腺癌间质成纤维细胞（ carcinoma-associated fibroblasts,CAFs）与乳腺癌细胞系MDA-MB-231共培养的体外细胞实验及裸鼠接种的在体动物实验,观察CAFs对乳腺癌细胞增殖、凋亡、侵袭和转移活性的影响,并探讨其作用机制。方法：体外实验：分离培养浸润性导管癌组织中CAFs和正常成纤维细胞（ normal fibroblasts,NFs）,然后分别与乳腺癌细胞MDA-MB-231体外共培养,采用MTT法、流式细胞仪、Ma-trigel人工模拟基底膜法分别检测乳腺癌细胞的增殖、凋亡、细胞黏附和侵袭能力。动物在体实验：选择乳腺癌细胞系MDA-MB-231、CAFs和NFs,结合生理盐水（NS）、基质细胞衍生因子-1（SDF-1）及其配体拮抗剂AMD3100,组成不同的组别并接种于裸鼠（共6组）。观察肿瘤的大小,有无淋巴结、肺、肝脏转移。留取血标本及肿瘤组织行SDF-1表达水平的检测。结果：MDA-MB-231与CAFs和NFs共培养后乳腺癌细胞的增殖活性显著增强,其中CAFs的作用较NFs更强（P＝0.011）;CAFs组的黏附能力（34.70±4.84个/视野）明显强于NFs组（20.16±3.09个/视野）,P＝0.000;而CAFs组的侵袭性（89.0±4.62个/视野）也明显强于NFs组（81.6±6.08个/视野,P＝0.045）。CAFs组中的MDA-MB-231的早期凋亡率（2.9±2.4）较NFs组（5.0±4.2）明显降低（P＝0.026）;MDA231﹢CAFs ﹢NS 组的种植肿瘤平均体积最大（9.092±2.662cm3, P＝0.000）;此外,该组共有4只（66.6％）,MDA231﹢NS组有2只（33.3％）存在腋窝淋巴结转移,未见肝肺转移灶。在MDA231﹢CAFs﹢NS组中,血标本 SDF -1值（75.25±16.23pg/ml）、肿瘤组织标本中 SDF -1mRNA值（11.686±8.926）、组织中SDF-1蛋白表达水平（1.006±0.327）均为最高,与其他各组相比均有统计学差异（ P＝0.000）。结论：CAFs可影响乳腺癌肿瘤细胞的生物学特性,具有促进肿瘤细胞增殖,增强其黏附、侵袭及转移能力。其机制可能是通过乳腺癌间质成纤维细胞分泌SDF-1与其特定的受体CXCR4结合这一信号通路来实现的。     

IGF-1R inhibition potentiates cytotoxic effects of chemotherapeutic agents in early stages of chemoresistant ovarian cancer cells

The kinetics and effect of hyper activated IGF-1R signaling is not well investigated during acquirement of platinum and taxol resistance in ovarian cancer cells. Herein we reported an upregulated IGF-1R expression in early stages of cisplatin paclitaxel and cisplatin–taxol resistance. Picropodophyllin, an IGF-1R inhibitor, alone and in combination with cisplatin, paclitaxel or both at lowest possible doses could reverse the resistance at early stages. Upregulated IGF-1R was also found in primary tumors of ovarian cancer patients after three to four cycles of platinum–taxol treatment. These findings indicate that a combination of cytotoxic agents and IGF-1R inhibitor is more effective at early stages of chemoresistant ovarian cancer.     

LPLUNC1 reduces glycolysis in nasopharyngeal carcinoma cells through the PHB1-p53/c-Myc axis

Cancer cells prefer glycolysis to support their proliferation. Our previous studies have shown that the long palate, lung, and nasal epithelial cell clone 1 (LPLUNC1) can upregulate prohibitin 1 (PHB1) expression to inhibit the proliferation of nasopharyngeal carcinoma (NPC) cells. Given that PHB1 is an important regulator of cell energy metabolism, we explored whether and how LPLUNC1 regulated glucose glycolysis in NPC cells. LPLUNC1 or PHB1 overexpression decreased glycolysis and increased oxidative phosphorylation (OXPHOS)-related protein expression in NPC cells, promoting phosphorylated PHB1 nuclear translocation through 14-3-3σ. LPLUNC1 overexpression also increased p53 but decreased c-Myc expression in NPC cells, which were crucial for the decrease in glycolysis and increase in OXPHOS-related protein expression induced by LPLUNC1 overexpression. Finally, we found that treatment with all-trans retinoic acid (ATRA) reduced the viability and clonogenicity of NPC cells, decreased glycolysis, and increased OXPHOS-related protein expression by enhancing LPLUNC1 expression in NPC cells. Therefore, the LPLUNC1-PHB1-p53/c-Myc axis decreased glycolysis in NPC cells, and ATRA upregulated LPLUNC1 expression, ATRA maybe a promising drug for the treatment of NPC.     

Co-targeting IGF-1R and c-kit: synergistic inhibition of proliferation and induction of apoptosis in H 209 small cell lung cancer cells

Most small cell lung cancers (SCLC) coexpress the c-kit protein tyrosine receptor kinase and its ligand stem cell factor, resulting in an autocrine loop. As SCLC growth is also driven by insulin-like growth factor-1 receptor (IGF-1R) signalling, tyrphostins AG 1024 and 1296 (inhibitors of IGF-1R and c-kit activity, respectively) were used to co-target these receptors in H 209 SCLC cells. Combination treatment caused synergy in proliferation inhibition and in apoptosis induction, and also enhanced reduction in phosphorylation of Erk1/Erk2, suggesting that co-targeting IGF-1R and c-kit in SCLC may be more effective than single-agent therapies.     

自分泌IGF-1/IGF-1R环路促进NK/T细胞淋巴瘤细胞株迁移和侵袭

目的 探讨IGF-1/IGF-1R信号通路对NK/T细胞淋巴瘤(NK/TCL)细胞株迁移和侵袭的作用及其调控机制.方法 采用反转录聚合酶链反应(RT-PCR)及免疫荧光技术检测IGF-1和IGF-1R的表达,Transwell技术观察NK/TCL细胞迁移和侵袭.酶联免疫吸附实验(ELISA)检测MMP-2、MMP-9及TIMP1水平.结果 NK/TCL细胞株SNK-1和SNK-6均表达IGF-1与IGF-1R,而健康人NK细胞不表达IGF-1R.IGF-1R抑制剂显著抑制SNK-1和SNK-6的迁移和侵袭.外源性IGF-1则促进细胞迁移及侵袭,而IGF-1R抑制剂能阻断该效应.IGF-1R下游相关激酶p38、PI3K及JNK的抑制剂均可降低细胞迁移能力.外源性IGF-1可上调MMP-2、MMP-9的分泌水平,IGF-1R抑制剂则抑制MMP-2、MMP-9的分泌.结论 NK/TCL细胞株中存在IGF-1/IGF-1R自分泌环路,并通过IGF-1/IGF-1R通路促进MMP-2、MMP-9分泌及IGF-1R下游p38、PI3K及JNK等激酶促进肿瘤细胞的迁移和侵袭.     

Reciprocal changes in gene expression profiles of cocultured breast epithelial cells and primary fibroblasts

The importance of epithelial‐stroma interaction in normal breast development and tumor progression has been recognized. To identify genes that were regulated by these reciprocal interactions, we cocultured a nonmalignant (MCF10A) and a breast cancer derived (MDA‐MB231) basal cell lines, with fibroblasts isolated from breast benign‐disease adjacent tissues (NAF) or with carcinoma‐associated fibroblasts (CAF), in a transwell system. Gene expression profiles of each coculture pair were compared with the correspondent monocultures, using a customized microarray. Contrariwise to large alterations in epithelial cells genomic profiles, fibroblasts were less affected. In MDA‐MB231 highly represented genes downregulated by CAF derived factors coded for proteins important for the specificity of vectorial transport between ER and golgi, possibly affecting cell polarity whereas the response of MCF10A comprised an induction of genes coding for stress responsive proteins, representing a prosurvival effect. While NAF downregulated genes encoding proteins associated to glycolipid and fatty acid biosynthesis in MDA‐MB231, potentially affecting membrane biogenesis, in MCF10A, genes critical for growth control and adhesion were altered. NAFs responded to coculture with MDA‐MB231 by a decrease in the expression of genes induced by TGFβ1 and associated to motility. However, there was little change in NAFs gene expression profile influenced by MCF10A. CAFs responded to the presence of both epithelial cells inducing genes implicated in cell proliferation. Our data indicate that interactions between breast fibroblasts and basal epithelial cells resulted in alterations in the genomic profiles of both cell types which may help to clarify some aspects of this heterotypic signaling. © 2009 UICC     

The GH1/IGF-1 axis polymorphisms and their impact on breast cancer development

The growth hormone 1/insulin-like growth factor-1 (GH1/IGF-1) axis plays an essential role in the development of the breast by regulating cell proliferation, differentiation and apoptosis. Imbalances within this axis lead to an aberrant signalling and recent research has focussed on the overexpression of these growth factors and their involvement in breast cancer development. The increased understanding of the molecular mechanisms and signalling pathways connected to the GH1/IGF-1 axis has provided important insights into aetiology, prevention and therapy for breast cancer. However, to identify the contribution of the GH1/IGF-1 signalling pathway to cancer risk still remains a challenge since the results of various studies are controversial. Here, we discuss the influence of low-penetrance polymorphisms in the genes along the GH1/IGF-1 axis and their impact on hormone levels and cancer risk, especially breast cancer. We point out what is known about the effects of the variants and show how the interaction of genetic variants affects breast cancer risk.     

IGF-1R和IRS-1在肺鳞癌组织中的表达及临床意义

目的 检测胰岛素样生长因子1受体(IGF-1R)和胰岛素受体底物1(IRS-1)在肺鳞癌组织中的表达,探究其在肺鳞癌发生发展中的作用及临床意义。方法 采用免疫组化法检测246例肺鳞癌组织与40例癌旁正常组织中IGF-1R、IRS-1的表达情况,并分析两者的相关性及与临床病理特征和预后的关系。结果 IGF-1R在肺鳞癌组织中的阳性表达率明显高于癌旁组织,其表达率分别为54.07%和32.5%,IRS-1在肺鳞癌组织中的阳性表达率明显低于癌旁组织,其表达率分别为38.21%和70%,各组间差异均有统计学意义(P＜0.05)。IGF-1R的表达与淋巴结转移相关(P＜0.05),IRS-1的表达与肺鳞癌组织的分化程度、淋巴结转移相关(P＜0.05)。IGF-1R阳性表达组患者的生存期明显短于IGF-1R阴性表达组患者,IRS-1阳性表达组患者的生存期明显长于IRS-1阴性表达组患者,差异有统计学意义(P＜0.001,P＜0.05)。IGF-1R与IRS-1在肺鳞癌组织中的表达呈负相关(r=-0.125,P＜0.001)。结论 IGF-1R、IRS-1都参与了肺鳞癌的发生、发展,且IGF-1R为独立预后因子。     

Sensitivity of breast cancer cell lines to the novel insulin-like growth factor-1 receptor (IGF-1R) inhibitor NVP-AEW541 is dependent on the level of IRS-1 expression

To investigate the potential value of targeting insulin-like growth factor-1 receptor (IGF-1R) in breast cancer, we examined the effects of NVP-AEW541, a selective small-molecule inhibitor of the IGF-1R tyrosine kinase, in a panel of 16 breast cancer cell lines. All cell lines expressed IGF-1R, but MCF-7 expressed much higher levels of insulin receptor substrate-1 (IRS-1) than the others. NVP-AEW541 was more potent at inhibiting growth of MCF-7 cells as compared to the others (IC₅₀, 1 μM vs. ≈7 μM). Comparing MCF-7 to T47D cells, which express IGF-1R at a level identical to MCF-7 but have less than 1/30 the amount of IRS-1, NVP-AEW541 caused cell-cycle arrest at the G1–S boundary, reduced in vitro cell migration, and enhanced the cytotoxic effects of vinorelbine and paclitaxel in MCF-7, but not in T47D. While NVP-AEW541 decreased the phosphorylation of IGF-1R in both cell lines, it inhibited phosphorylation of Akt and disrupted the IRS-1/PI3 K complex only in MCF-7. These findings suggest that inhibiting IGF-1R may be an effective therapeutic strategy for breast cancers that co-express IGF-1R and IRS-1 at high levels.     

MiR-448 suppresses cell proliferation and glycolysis of hepatocellular carcinoma through inhibiting IGF-1R expression

BackgroundMicroribonucleic acids (miRNAs) have been shown to play important roles in hepatocellular carcinoma (HCC) progression. MiR-448 has frequently been shown to be a tumor suppressor, and is abnormally expressed in HCC tumor tissues. However, little is known about the role of miR-448 in HCC development. In this article, the regulatory role of miR-448 on insulin-like growth factor 1 receptor (IGF-1R) in modulating hepatoma cell viability and glycolysis was investigated.MethodsThe expression of miR-448 profiles in clinical tumor tissues and cell lines was examined using quantitative real-time polymerase chain reaction (qRT-PCR). HepG2 and Huh7 cells were transfected with miR-448 mimics, inhibitors, and scramble sequences. Cell viability and apoptosis were determined by a Cell Counting Kit-8 assay and a flow cytometry analysis. IGF-1R, a potential target of miR-448, was selected following a bioinformatic analysis, and the regulatory effects of miR-448 on IGF-1R expression was confirmed by luciferase reporter assay, qRT-PCR, and western blot. Glucose uptake, lactate production, and adenosine triphosphate (ATP) generation were detected by corresponding kits.ResultsDecreased miR-448 expression was observed in both HCC patients’ tumor tissues and hepatoma cells in vitro. The overexpression of miR-448 in HepG2 and Huh7 cells decreased cell viability and increased apoptosis. Additionally, the overexpression of miR-448 or the knockdown of IGF-1R lowered the level of glucose uptake, lactate production, and ATP generation, while the knockdown of miR-448 increased glycolysis. Further, aberrantly expressed miR-448 downregulated IGF-1R levels, while the inhibition of miR-448 resulted in the upregulation of IGF-1R in both HepG2 and Huh7 cells. In addition, miR-448 interacted with the wild-type 3''untranslated regions (3''UTRs) of IGF-1R, but had no effect on the mutant 3''UTRs. The expression of IGF-1R was increased in HCC patients’ tumor tissues and serum, and was inversely correlated with miR-448 expression.ConclusionsThe increased expression of miR-448 appears to downregulate the expression of IGF-1R by interacting with the 3’UTR in HCC progression. These findings highlight its role as a potential target for HCC therapy.