Epithelial V‐like antigen 1 promotes hepatocellular carcinoma growth and metastasis via the ERBB‐PI3K‐AKT pathway

The role of epithelial V‐like antigen 1 (EVA1) has been well studied in thymic development and homostasis; however, its putative relationship with cancer remains largely unknown. Therefore, here we investigated the role of EVA1 in hepatocellular carcinoma. Interestingly, EVA1 expression was significantly increased in hepatocellular carcinoma (HCC) and was also associated with a poor prognosis and recurrence in HCC patients. Overexpression of EVA1 promoted cell growth, invasion and migration in vitro. Consistently, knockdown of EVA1 expression inhibited proliferation and migration in vitro, while repressing metastasis of HCC cells in vivo. RNA‐seq analysis indicated that EVA1 is able to upregulate the expression of genes in the ERBB3‐PI3K pathway. Accordingly, an increased level of AKT phosphorylation was detected in HCC cells after EVA1 overexpression. LY294002, a PI3K inhibitor, inhibited AKT phosphorylation and rescued the tumor‐promoting effect of EVA1 overexpression. Altogether, the present study has revealed the oncogenic role of EVA1 during HCC progression and metastasis through the ERBB‐PI3K‐AKT signaling pathway, reiterating the potential use of EVA1 as a therapeutic target and/or prognostic marker for HCC.     

肝细胞癌高表达基因TPT1转染对肝细胞系生物学行为的影响

目的 将TPT1转染肝癌细胞系SMMC-7721和肝细胞系L-02,观察肝细胞系生物学行为的变化.方法 将连有TPT1的、带有绿色荧光蛋白标签的真核报告表达载体pEGFP-N3TPT1,通过Lipofectamine分别转染SMMC-7721和L-02细胞,同时设pEGFP-N3对照.采用逆转录聚合酶链反应(RT-PCR)检测TPT1 mRNA水平,四甲基偶氮唑蓝(MTT)法、软琼脂克隆形成实验、细胞周期分析检测细胞增殖和致瘤性.结果 pEGFP-N3TPT1转染后,SMMC-7721细胞TPT1 mRNA相对表达水平与对照组的比值为1.78,L-02细胞TPT1 mRNA相对表达水平与对照组的比值为2.59.pEGFP-N3TPT1转染可明显增强肝细胞的增殖能力,转染SMMC-7721后24、48、72、96h的吸光度(A)值分别为0.80、1.56、2.69和2.94,均高于pEGFP-N3(分别为0.71、1.23、1.92和2.75)和脂质体对照(分别为0.76、1.27、1.89和2.78),差异均有统计学意义(均P＜0.05).在接种500个和1000个细胞时,pEGFP-N3TPT1组软琼脂克隆形成数分别为(6.00±1.73)个和(12.00±2.65)个,pEGFP-N3组软琼脂克隆形成数分别为(1.00±1.00)个和(7.00±1.00)个(P＜0.05).pEGFP-N3TPT1转染后的SMMC-7721细胞增殖指数(P1)为40.9%,高于pEGFP-N3组(26.4%).EGFP-N3TPT1转染正常肝细胞L-02后,24、48、72、96、120 h测得的A值分别为0.87、1.11、1.55、2.12和2.42,均高于pEGFP-N3组(分别为0.65、0.79、1.02、1.49和1.96)和脂质体组(分别为0.67、0.82、0.89、1.56和1.85),差异有统计学意义(P＜0.05);pEGFP-N3TPT1组平板克隆数为(18.00±2.00)个,pEGFP-N3组为(7.00±2.65)个(P＜0.05),但L-02细胞不能在软琼脂中形成克隆.pEGFP-N3TPT1转染后L-02细胞的PI为35.9%,高于pEGFP-N3组(26.1%).结论 TPT1转染可增强肝癌细胞SMMC-7721的恶性表型,促进正常肝细胞L-02的增殖能力,但不能使L-02发生恶性转化.

Abstract：

Objective The aim of this study was to transfect TPT1 into cell lines SMMC-7721 and L-02, seperately, and to observe the changes of biological behaviors of the cell lines. Methods Through lipofectamine, the eukaryotic report expression vector containing TPT1 ORF( open reading frame), pEGFP-N3TPT1, were transducted into hepatocarcinoma cell line SMMC-7721 cells and normal liver cell line L-02 cells, seperately. The transduction was repeated three times in 24 hrs. The differences of biological behaviors between the pEGFP-N3TPT1 and pEGFP-N3 groups were studied by RT-PCR, MTT assay, soft agar colony formation assay and cell cycle analysis. Results The pEGFP-N3TPT1 transfected cells had a high mRNA level in the two cell lines ( P ＜ 0. 05 ) compared with the pEGFP-N3 controls. The ability of proliferation and the soft agar colony formation were enhanced in the SMMC-7721 transducted cells with pEGFP-N3TPT1 compared with that transducted with pEGFP-N3 ( P ＜ 0.05 ), and the cell cycle analysis showed that the cells in the phase G2 + S/M increased after pEGFP-N3TPT1 transduction. In the L-02 cell line, we obtained similar results, pEGFP-N3TPT1 enhanced the colony formation in plate( P ＜0.05 ), but not make it form colony in soft agar. Conclusions TPT1 can enhance malignant phenotype of SMMC-7721 cells and promote the growth of L-02 cells, but not transform L-02 into malignant phenotype.     

Long Noncoding RNA PlncRNA-1 Promotes Colorectal Cancer Cell Progression by Regulating the PI3K/Akt Signaling Pathway

Accumulating evidence has indicated that long noncoding RNA (lncRNA) PlncRNA-1 plays an important regulatory role in cancers. However, the expression and biological functions of PlncRNA-1 in colorectal cancer (CRC) are still unclear. In the present study, we determined the expression of PlncRNA-1 in CRC and explored the function of PlncRNA-1 on CRC cell progression. The results showed that PlncRNA-1 was significantly increased in CRC tissues and cell lines; high PlncRNA-1 expression was associated with depth of invasion, lymph node metastasis, and TNM stage of CRC patients. Kaplan–Meier curve analysis showed that patients with high PlncRNA-1 expression had a poor overall survival. PlncRNA-1 knockdown remarkably reduced cell proliferation, migration, and invasion and promoted cell apoptosis in vitro. In vivo xenograft experiments showed that PlncRNA-1 inhibition significantly suppressed tumor growth. Finally, we used an agonist (740Y-P) of the PI3K/Akt signaling pathway; function assays showed that PlncRNA-1 exerted its effects by targeting the PI3K/Akt signaling pathway in CRC. Taken together, our data suggested that PlncRNA-1 might act as an oncogene in CRC progression and serve as a potential biomarker and therapeutic target for the treatment of CRC.     

Id‐1 promotes tumorigenicity and metastasis of human esophageal cancer cells through activation of PI3K/AKT signaling pathway

Id‐1 (inhibitor of differentiation or DNA binding) is a helix‐loop‐helix protein that is overexpressed in many types of cancer including esophageal squamous cell carcinoma (ESCC). We previously reported that ectopic Id‐1 expression activates the phosphatidylinositol‐3‐kinase (PI3K)/protein kinase B (AKT) signaling pathway in human esophageal cancer cells. In this study, we confirmed a positive correlation between Id‐1 and phospho‐AKT (Ser473) expressions in ESCC cell lines, as well as in ESCC on a tissue microarray. To investigate the significance of Id‐1 in esophageal cancer progression, ESCC cells with stable ectopic Id‐1 expression were inoculated subcutaneously into the flank of nude mice and were found to form larger tumors that showed elevated Ki‐67 proliferation index and increased angiogenesis, as well as reduced apoptosis, compared with control cells expressing the empty vector.The Id‐1‐overexpressing cells also exhibited enhanced metastatic potential in the experimental metastasis assay. Treatment with the PI3K inhibitor LY294002 attenuated the tumor promotion effects of Id‐1, indicating that the effects were mediated by the PI3K/AKT signaling pathway. In addition, our in vitro experiments showed that ectopic Id‐1 expression altered the expression levels of markers associated with epithelial–mesenchymal transition and enhanced the migration ability of esophageal cancer cells. The Id‐1‐overexpressing ESCC cells also exhibited increased invasive potential, which was in part due to PI3K/AKT‐dependent modulation of matrix metalloproteinase‐9 expression. In conclusion, our results provide the first evidence that Id‐1 promotes tumorigenicity and metastasis of human esophageal cancer in vivo and that the PI3K inhibitor LY294002 can attenuate these effects. © 2009 UICC     

Cyclooxygenase‐2 inhibition inhibits PI3K/AKT kinase activity in epithelial ovarian cancer

Cyclooxygenase‐2 (COX‐2) expression contributes to tumor growth and invasion in epithelial ovarian cancer (EOC). COX‐2 inhibitors exhibit important anticarcinogenic potential against EOC, but the molecular mechanisms underlying this effect and relation with PI3‐kinase/AKT signaling remain the subject of intense investigations. Therefore, the role of COX‐2 in EOC and its cross talk with PI3‐kinase/AKT pathway were investigated using a large series of EOC tissues in a tissue micro array (TMA) format followed by in vitro and in vivo studies using EOC cell lines and NUDE mice. Clinically, COX‐2 was overexpressed in 60.3% of EOC and was significantly associated with activated AKT (p < 0.0001). Cox‐1 expression was seen in 59.9% but did not associate with AKT. Our in vitro data using EOC cell line showed that inhibition of COX‐2 by aspirin, selective inhibitor NS398 and gene silencing by COX‐2 specific siRNA impaired phosphorylation of AKT resulting decreased downstream signaling leading to cell growth inhibition and induction of apoptosis. Finally, treatment of MDAH2774 cell line xenografts with aspirin resulted in growth inhibition of tumors in NUDE mice via down‐regulation of COX‐2 and AKT activity. These data identify COX‐2 as a potential biomarker and therapeutic target in distinct molecular subtypes of ovarian cancer.     

Long noncoding RNA MAPKAPK5‐AS1 promotes colorectal cancer proliferation by partly silencing p21 expression

Colorectal cancer (CRC) is the third most common malignancy in the world, and long noncoding RNA (lncRNA) plays a critical role in carcinogenesis. Here, we report a novel lncRNA, MAPKAPK5‐AS1, that acts as a critical oncogene in CRC. In addition, we attempted to explore the functions of MAPKAPK5‐AS1 on tumor progression in vitro and in vivo. Quantitative RT‐PCR was used to examine the expression of MAPKAPK5‐AS1 in CRC tissues and cells. Expression of MAPKAPK5‐AS1 was significantly upregulated in 50 CRC tissues, and increased expression of MAPKAPK5‐AS1 was found to be associated with greater tumor size and advanced pathological stage in CRC patients. Knockdown of MAPKAPK5‐AS1 significantly inhibited proliferation and caused apoptosis in CRC cells. We also found that p21 is a target of MAPKAPK5‐AS1. In addition, we are the first to report that MAPKAPK5‐AS1 plays a carcinogenic role in CRC. MAPKAPK5‐AS1 is a novel prognostic biomarker and a potential therapeutic candidate for CRC cancer.     

Long noncoding RNA actin filament‐associated protein 1 antisense RNA 1 promotes malignant phenotype through binding with lysine‐specific demethylase 1 and repressing HMG box‐containing protein 1 in non‐small‐cell lung cancer

The number of documented long noncoding RNAs (lncRNAs) has dramatically increased, and their biological functions and underlying mechanisms in pathological processes, especially cancer, remain to be elucidated. Actin filament‐associated protein 1 antisense RNA 1 (AFAP1‐AS1) is a 6810‐nt lncRNA located on chromosome 4p16.1 that was first reported to be upregulated in esophageal adenocarcinoma tissues and cell lines. Here we reported that AFAP1‐AS1, recruiting and binding to lysine‐specific demethylase 1 (LSD1), was generally overexpressed in human non‐small‐cell lung cancer (NSCLC) tissues using quantitative real‐time PCR. Higher AFAP1‐AS1 expression was significantly correlated with larger tumor size (P = .008), lymph node metastasis (P = .025), higher TNM stage (P = .024), and worse overall survival in NSCLC patients. In vitro experiments revealed that AFAP1‐AS1 downregulation inhibited cell migration and induced apoptosis; AFAP1‐AS1 knockdown also hindered tumorigenesis in vivo. Moreover, mechanistic investigations including RNA immunoprecipitation and ChIP assays validated that AFAP1‐AS1 repressed HMG box‐containing protein 1 (HBP1) expression by recruiting LSD1 to the HBP1 promoter regions in PC‐9 and H1975 cells. Furthermore, HBP1 functions as a tumor suppressor, and its ectopic expression hindered cell proliferation. Rescue assays determined that the oncogenic effect of AFAP1‐AS1 is partially dependent on the epigenetic silencing of HBP1. In conclusion, our results indicate that AFAP1‐AS1 is carcinogenic and that the AFAP1‐AS1/LSD1/HBP1 axis could constitute a new therapeutic direction for NSCLC.     

Hepatitis B virus X protein promotes hepatoma cell invasion and metastasis by stabilizing Snail protein

A high incidence of tumor recurrence and metastasis has been reported in hepatocellular carcinoma (HCC) patients with chronic hepatitis B virus (HBV) infection. Although the pathological relevance and significance of hepatitis B virus X protein (HBx) in HBV‐associated hepatocarcinogenesis attracted much attention in recent years, the role and molecular mechanism for HBx in hepatoma invasion and metastasis remains poorly understood. In the present study, we found that HBx expression could induce epithelial–mesenchymal transition in hepatoma and hepatic cells. This effect was shown due to stabilized Snail protein through activating the phosphatidylinositol 3‐kinase/protein kinase B/glycogen synthase kinase‐3β (PI3K/AKT/GSK‐3β) signal pathway by HBx expression. Functional studies revealed that HBx expression could enhance hepatoma cell migration and invasion in vitro. Moreover, stable HBx expression could also facilitate intrahepatic and distant lung metastasis of HCC in a nude mice tumor metastasis model in vivo. The correlation between increased PI3K/AKT/GSK‐3β signaling with elevated Snail protein level was also observed in HCC tumor tissues with intrahepatic metastasis or chronic HBV infection. These results revealed a novel function of HBx in promoting epithelial–mesenchymal transition through Snail protein stabilization by activating PI3K/AKT/GSK‐3β signaling, thus facilitating tumor invasion and metastasis during HCC progression. This could provide a putative molecular mechanism for tumor recurrence and metastasis in HBV‐associated HCC patients.     

动力相关蛋白-1(MRP-1/CD9)对卵巢癌细胞体外增殖和运动的影响

目的：动力相关蛋白-1（MRP-1／CD9）是四跨膜蛋白超家庭（transmetubrane 4,stperfanily,TM4SF）成员之一,参与调控细胞的生长,分化,细胞间粘附和迁移,本实验旨在研究MRP-1 CD9对人卵巢癌SKON-3细胞株体外增殖和运动能力的影响并探讨其与PI4K/AKT信号通路的相关性,方法：应用RT-PCR获得CD9全长cDNA片段,正向插入pcDNA3.1表达载体,将重组质粒导入SKOV-3细胞中,应用RT-PCR efse一流式细胞测定和单层伤口愈合实验等方法观察梁前后SKOV-3细胞PI4K和AKTmRNA表达水平,细胞增殖及其运动能力变化,结果：成功构建正义全长CD9真核表达载体,获得稳定表达CD9的SKOV-3克隆株,与穿空质粒转染和不转染的SKON-3细胞相比,SKON-3/CD9细胞PI4KmRNA的表达明显被抑制,抵制率为40%;AKTmRNA的表达水平上调3.13倍,细胞增殖和运动能力均有明显升高.结论：CD9促进人卵巢癌SKOV-3细胞的体外增殖 和运动能力,可能是通过PI4K/AKT信号通路发挥作用的,对卵巢癌恶性进展发挥重要作用.     

MYC-binding lncRNA EPIC1 promotes AKT-mTORC1 signaling and rapamycin resistance in breast and ovarian cancer

AKT-mTORC1 (mammalian target of rapamycin complex 1) signaling pathway plays a critical role in tumorigenesis and can be targeted by rapamycin. However, the underlying mechanism of how long noncoding RNA (lncRNAs) regulate the AKT-mTORC1 pathway remains unclear. EPIC1 (epigenetically-induced lncRNA 1) is a Myc-binding lncRNA, which has been previously demonstrated to be overexpressed in multiple cancer types. In a pathway analysis including 4962 cancer patients, we observed that lncRNA EPIC1 expression was positively correlated with the AKT-mTORC1 signaling pathway in more than 10 cancer types, including breast and ovarian cancers. RNA-seq analysis of breast and ovarian cancer cells demonstrated that EPIC1-knockdown led to the downregulation of genes in the AKT-mTORC1 signaling pathway. In MCF-7, OVCAR4, and A2780cis cell lines, EPIC1 knockdown and overexpression, respectively, inhibited and activated phosphorylated AKT and the downstream phosphorylation levels of 4EBP1 and S6K. Further knockdown of Myc abolished the EPIC1′s regulation of AKT-mTORC1 signaling; suggested that the regulation of phosphorylation level of AKT, 4EBP1, and S6K by EPIC1 depended on the expression of Myc. Moreover, EPIC1 overexpressed MCF-7, A2780cis, and OVCAR4 cells treated with rapamycin showed a significant decreasing in rapamycin mediated inhibition of p-S6K and p-S6 comparing with the control group. In addition, Colony Formation assay and MTT assay indicated that EPIC1 overexpression led to rapamycin resistance in breast and ovarian cancer cell lines. Our results demonstrated the lncRNA EPIC1 expression activated the AKT-mTORC1 signaling pathway through Myc and led to rapamycin resistance in breast and ovarian cancer.     

PD-L1 Induces Epithelial–Mesenchymal Transition in Nasopharyngeal Carcinoma Cells Through Activation of the PI3K/AKT Pathway

Nasopharyngeal cancer (NPC) is a malignant epithelial carcinoma of the head and neck. Cancer therapy targeting programmed cell death protein-1 (PD-1) or programmed death ligand-1 (PD-L1) is revolutionary. However, the tumorigenic mechanism of PD-L1 is not yet clear in NPC. Here we demonstrated an oncogenic role of PD-L1 via activating PI3K/AKT in NPC cells. PD-L1 overexpression was frequently detected in NPC biopsies and cell lines by qRT-PCR. PD-L1 overexpression and knockdown demonstrated that PD-L1 promoted NPC cell invasion and metastasis in vitro and in vivo. Mechanistically, PD-L1 prominently activated the epithelial–mesenchymal transition (EMT) process in a PI3K/AKT-dependent manner. Taken together, we found that PD-L1 overexpression confers NPC cell malignancy and aggressiveness via activating the downstream PI3K/AKT signaling. Thus, these results provide a basis for diagnosis and treatment of NPC.     

Podocalyxin‐like protein promotes gastric cancer progression through interacting with RUN and FYVE domain containing 1 protein

Podocalyxin‐like protein (PODXL), a transmembrane glycoprotein with anti‐adhesive properties, is associated with an aggressive tumor phenotype and poor prognosis of several cancers. To elucidate the biological significance of PODXL and its molecular mechanism in gastric cancer (GC), we investigated the expression of PODXL in GC samples and assessed its effects on biological behaviors and the related signaling pathways in vitro and in vivo. Moreover, the possible and closely interacted partners of PODXL were identified. Our data showed that the protein or mRNA level of PODXL was significantly upregulated in tissues or serum of GC patients compared with normal‐appearing tissues (NAT) or those of healthy volunteers. Overall survival (OS) curves showed that patients with high PODXL levels in tissues or serum had a worse 5‐year OS. In vitro, restoring PODXL expression promoted tumor progression by increasing cell proliferation, colony formation, wound healing, migration and invasion, as well as suppressing the apoptosis. Furthermore, the PI3K/AKT, NF‐κB and MAPK/ERK signaling pathways were activated. There was a significant positive correlation between PODXL and RUN and FYVE domain containing 1 (RUFY1) expression in tissues or serum. Subsequent mass spectrometry analysis, co‐immunoprecipitation assays and western blot analysis identified PODXL/RUFY1 complexes in GC cells, and silencing RUFY1 expression in GC cells significantly attenuated PODXL‐induced phenotypes and their underlying signaling pathways. Our results suggested that PODXL promoted GC progression via a RUFY1‐dependent signaling mechanism. New GC therapeutic opportunities through PODXL and targeting the PODXL/RUFY1 complex might improve cancer therapy.     

Long non‐coding RNA RP11‐552M11.4 promotes cells proliferation,migration and invasion by targeting BRCA2 in ovarian cancer

The present study aimed to investigate the effect of long non‐coding RNA (lncRNA) RP11‐552M11.4 on cell proliferation, apoptosis, migration and invasion as well as its targeting genes in epithelial ovarian cancer (EOC) cells. LncRNA RP11‐552M11.4 expression was detected in 67 tumor tissues and paired adjacent tissues obtained from EOC patients. lncRNA RP11‐552M11.4 mimic/inhibitor plasmids were transferred into ovarian cancer cells (SKOV3, A‐2780) and normal ovarian epithelial cells (IOSE80 cells). In addition, rescue experiment was carried out by transferring BRCA2 inhibitor&lncRNA RP11‐552M11.4 inhibitor plasmids into SKOV3 and A‐2780 cells. qPCR, western blot, CKK‐8, Annexin V/propidium iodide (AV/PI), wound‐healing and Matrigel invasion assays were carried out to detect RNA expression, protein expression, cell proliferation, apoptosis, migration, and invasion, respectively. LncRNA RP11‐552M11.4 expression was elevated in tumor tissues compared with paired adjacent tissues and correlated with higher pathological grade, International Federation of Gynecology and Obstetrics stage and worse overall survival in EOC patients. LncRNA RP11‐552M11.4 promoted SKOV3 cell proliferation, migration and invasion whereas it inhibited apoptosis. Rescue experiment and luciferase reporter assay showed that lncRNA RP11‐552M11.4 regulated SKOV3 cells functions through binding BRCA2. Further experiments in A‐2780 cells also validated that lncRNA RP11‐552M11.4 induced A‐2780 cell proliferation while repressing apoptosis by targeting BRCA2. In addition, upregulation of lncRNA RP11‐552M11.4 increased IOSE80 cell proliferation, migration and invasion while decreasing apoptosis. In conclusion, lncRNA RP11‐552M11.4 correlates with worse prognosis, and promotes cell proliferation, migration, invasion, and inhibits cell apoptosis by down‐regulating BRCA2 in EOC.