丙酮酸乙酯通过下调蛋白激酶B通路抑制人胃癌细胞侵袭转移的研究

目的探讨丙酮酸乙酯（EP）对人胃癌SGC-7901细胞侵袭转移的抑制效果及机制。方法噻唑蓝比色分析法 (MTT法)测定EP在胃癌SGC-7901细胞中的半数抑制浓度(IC50)。不同浓度EP加入到胃癌细胞后,实时定量PCR检测蛋白激酶B（Akt）的mRNA表达水平;Western blot检测Akt、p-Akt、基质金属蛋白酶-2 (MMP-2)和MMP-9的蛋白表达水平。划痕和Transwell实验评价胃癌细胞侵袭转移的能力。通过建立裸鼠皮下移植瘤模型,免疫组织化学进一步验证以上蛋白的表达水平。结果EP在胃癌SGC-7901细胞中的IC50为36.73 mmol/L。EP抑制Akt mRNA的表达及下调Akt、p-Akt、MMP-2和MMP-9的蛋白表达。划痕实验显示EP可抑制胃癌细胞的迁移运动能力;Transwell显示,与对照组（93.33±4.16）相比,EP 10 mmol/L组（75.34±4.73）、EP 20 mmol/L组（61.34±3.06）及EP 40 mmol/L组（39.00±3.00）的侵袭转移细胞数明显减少 (P均<0.001)。免疫组组织化学进一步证实了Western blot的检测结果。结论EP通过下调Akt通路抑制人胃癌细胞的侵袭和转移,对癌症具有一定的治疗效果。     

PTHrP increases xenograft growth and promotes integrin alpha6beta4 expression and Akt activation in colon cancer

Parathyroid hormone-related protein (PTHrP) is expressed by human colon cancer tissue and cell lines. Expression of PTHrP and phosphatidylinositol 3-kinase (PI3-K) pathway components correlates with the severity of colon carcinoma. Here we observed a positive effect of endogenous PTHrP on LoVo (human colon cancer) cell proliferation, migration, invasion, integrin alpha6 and beta4 expression, and p-Akt levels. There was a direct correlation between PTHrP expression and anchorage-independent cell growth. PTHrP significantly increased xenograft growth; tumors from PTHrP-overexpressing cells showed increased expression of integrins alpha6 and beta4, and PI3-K pathway components. The higher expression of PTHrP in human colon cancer adenocarcinoma vs. normal colonic mucosa was accompanied by increased integrin alpha6 and beta4 levels. Elevated PTHrP expression in colon cancer may thus upregulate integrin alpha6beta4 expression, with consequent PI3-K activation. Targeting PTHrP might result in effective inhibition of tumor growth, migration, and invasion.     

Role of p53 up-regulated modulator of apoptosis and phosphorylated Akt in melanoma cell growth, apoptosis, and patient survival

Malignant melanoma is an aggressive and chemoresistant form of skin cancer characterized by rapid metastasis and poor patient prognosis. The development of innovative therapies with improved efficacy is critical to treatment of this disease. Here, we show that aberrant expression of two proteins, p53 up-regulated modulator of apoptosis (PUMA) and phosphorylated Akt (p-Akt), is associated with poor patient survival. Using tissue microarray analysis, we found that patients exhibiting both weak PUMA expression and strong p-Akt expression in their melanoma tumor tissue had significantly worse 5-year survival than patients with either weak PUMA or strong p-Akt expression alone (P < 0.001). Strikingly, no patients exhibiting strong PUMA expression and weak p-Akt expression in primary tumor tissue died within 5 years of diagnosis. We propose a two-pronged therapeutic strategy of (a) boosting PUMA expression and (b) inhibiting Akt phosphorylation in melanoma tumor tissue. Here, we report that a recombinant adenovirus containing human PUMA cDNA (ad-PUMA) efficiently inhibits human melanoma cell survival in vitro, rapidly induces apoptosis, and dramatically suppresses human melanoma tumor growth in a severe combined immunodeficient mouse xenograft model. In melanoma cells strongly expressing p-Akt, we show that Akt/protein kinase B signaling inhibitor-2 (API-2; a small-molecule Akt inhibitor) reduces cell survival in a dose- and time-dependent manner and enhances ad-PUMA-mediated growth inhibition of melanoma cells. Finally, we show that, by combining ad-PUMA and API-2 treatments, human melanoma tumor growth can be inhibited by >80% in vivo compared with controls. Our results suggest that a strategy to correct dysregulated PUMA and p-Akt expression in malignant melanoma may be an effective therapeutic option.     

Hypoxia-increased RAGE and P2X7R expression regulates tumor cell invasion through phosphorylation of Erk1/2 and Akt and nuclear translocation of NF-{kappa}B

The role of hypoxia in regulating tumor progression is still controversial. Here, we demonstrate that, similarly to what previously observed by us in human prostate and breast tumor samples, hypoxia increases expression of the receptor for advanced glycation end products (RAGE) and the purinergic receptor P2X7 (P2X7R). The role of hypoxia was shown by the fact that hypoxia-inducible factor (HIF)-1α silencing downregulated RAGE and P2X7R protein levels as well as nuclear factor-kappaB (NF-κB) expression. In contrast, NF-κB silencing reduced P2X7R expression without affecting RAGE protein levels or nuclear accumulation of HIF-1α. Treatment of hypoxic tumor cells with HMGB1 and BzATP ligands, respectively, of RAGE and P2X7R, activated a signaling pathway that, through Akt and Erk phosphorylation, determines nuclear accumulation of NF-κB and increases cell invasion. Inhibition of Akt by SH5 and Erk by INH1 prevented both nuclear translocation of NF-κB and cell invasion. Moreover, silencing RAGE and P2X7R abolished nuclear accumulation of NF-κB as well as cell invasion without affecting HIF-1α stabilization. Once in the nucleus, NF-κB would contribute to cell survival and invasion under hypoxia, by maintaining RAGE and P2X7R expression levels and matrix metalloproteinases 2 and 9 synthesis. These results show that, hypoxia can upregulate expression levels of membrane receptors that, by binding extracellular molecules eventually released by necrotic cells, contribute to the increased invasiveness of transformed tumor cells. Moreover, these observations strengthen our working hypothesis that upregulation of damage-associated molecular patterns receptors by HIF-1α represents the crucial event bridging hypoxia and inflammation in obtaining the malignant phenotype.     

PGE2通过EP1受体促进肝癌细胞生长和侵袭的研究进展

前列腺素E2（PGE2）是一种参与肝癌细胞生长与侵袭的重要细胞因子。PGE2通过与细胞膜表面的EP受体结合来发挥其调控肿瘤发生、发展的作用。在肝癌中,PGE2通过前列腺素E受体1（EP1）受体调节EGFR／PI3K／Akt、Src／EGFR／p44／42 MAPK／mTOR等信号通路影响Survivin、YB-1等关键物质,促进肝癌细胞生长和侵袭。现就近年来PGE2通过EP1受体促进肝癌细胞生长和侵袭作用机制的研究进行综述。     

Low molecular weight heparin suppresses receptor for advanced glycation end products‐mediated expression of malignant phenotype in human fibrosarcoma cells

The receptor for advanced glycation end products (RAGE) is a pattern‐recognition receptor and its engagement by ligands such as high mobility group box 1 (HMGB1) is implicated in tumor growth and metastasis. Low molecular weight heparin (LMWH) has an antagonistic effect on the RAGE axis and is also reported to exert an antitumor effect beyond the known activity of anticoagulation. However, the link between the anti‐RAGE and antitumor activities of LMWH has not yet to be fully elucidated. In this study, we investigated whether LMWH could inhibit tumor cell proliferation, invasion, and metastasis by blocking the RAGE axis using in vitro and in vivo assay systems. Stably transformed HT1080 human fibrosarcoma cell lines were obtained, including human full‐length RAGE‐overexpressing (HT1080^RAGE), RAGE dominant‐negative, intracellular tail‐deleted RAGE‐overexpressing (HT1080^dnRAGE), and mock‐transfected control (HT1080^mock) cells. Confocal microscopy showed the expression of HMGB1 and RAGE in HT1080 cells. The LMWH significantly inhibited HMGB1‐induced NFκB activation through RAGE using an NFκB‐dependent luciferase reporter assay and the HT1080 cell lines. Overexpression of RAGE significantly accelerated, but dnRAGE expression attenuated HT1080 cell proliferation and invasion in vitro, along with similar effects on local tumor mass growth and lung metastasis in vivo. Treatment with LMWH significantly inhibited the migration, invasion, tumor formation, and lung metastasis of HT1080^RAGE cells, but not of HT1080^mock or HT1080^dnRAGE cells. In conclusion, this study revealed that RAGE exacerbated the malignant phenotype of human fibrosarcoma cells, and that this exacerbation could be ameliorated by LMWH. It is suggested that LMWH has therapeutic potential in patients with certain types of malignant tumors.     

Combined targeting of high‐mobility group box‐1 and interleukin‐8 to control micrometastasis potential in gastric cancer

Micrometastasis is the major cause of treatment failure in gastric cancer (GC). Because epithelial‐to‐mesenchymal transition (EMT) is considered to develop prior to macroscopic metastasis, EMT‐promoting factors may affect micrometastasis. This study aimed to evaluate the role of extracellular high‐mobility group box‐1 (HMGB1) in EMT and the treatment effect of combined targeting of HMGB1 and interleukin‐8 (IL‐8) at early‐stage GC progression through interrupting EMT promotion. Extracellular HMGB1 was induced by human recombinant HMGB1 and pCMV‐SPORT6‐HMGB1 plasmid transfection. EMT activation was evaluated by immunoblotting, immunofluorescence and immunohistochemistry. Increased migration/invasion activities were evaluated by in vitro transwell migration/invasion assay using all histological types of human GC cell lines (N87, MKN28 SNU‐1 and KATOIII), N87‐xenograft BALB/c nude mice and human paired serum‐tissue GC samples. HMGB1‐induced soluble factors were measured by chemiluminescent immunoassay. Inhibition effects of tumor growth and EMT activation by combined targeting of HMGB1 and IL‐8 were evaluated in N87‐xenograft nude mice. Serum HMGB1 increases along the GC carcinogenesis and reaches maximum before macroscopic metastasis. Overexpressed extracellular HMGB1 promoted EMT activation and increased cell motility/invasiveness through ligation to receptor for advanced glycation end products. HMGB1‐induced IL‐8 overexpression contributed the HMGB1‐induced EMT in GC in vitro and in vivo. Blocking HMGB1 caused significant reduction of tumor growth, and addition of human recombinant IL‐8 rescues this antitumor effects. Our results imply the role of HMGB1 in EMT through IL‐8 mediation, and a potential mechanism of GC micrometastasis. Our observations suggest combination strategy of HMGB1 and IL‐8 as a promising diagnostic and therapeutic target to control GC micrometastasis.     

银杏内酯B通过阻抑PI3K/Akt/mTOR信号通路抑制胃癌HGC-27 细胞的恶性生物学行为

目的：探讨银杏内酯B（GKB）是否通过阻抑PI3K/Akt/mTOR信号通路抑制胃癌HGC-27细胞的增殖、凋亡、迁移及侵袭。方法：将HGC-27细胞分为对照、GKB低剂量（100 mg/L）、GKB高剂量（200 mg/L）、GKB高剂量（200 mg/L）+740Y-P（PI3K激活剂）、Ly294002（PI3K抑制剂）组。采用MTT、Edu、FCM、Transwell实验分别检测各组细胞的增殖、凋亡、迁移和侵袭能力,qPCR和WB法分别检测各组细胞中PI3K mRNA、Akt mRNA、mTOR mRNA和Ki-67、caspase-3、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白的表达。构建胃癌HGC-27细胞裸鼠移植瘤模型,观察GKB对移植瘤生长的影响,WB法检测移植瘤组织中Ki-67、caspase-3、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白的表达。结果：体外实验结果表明,与对照组相比,GKB低剂量组、GKB高剂量组、Ly294002组HGC-27细胞的增殖活力及细胞增殖率、迁移和侵袭细胞数,PI3K、Akt、mTOR mRNA表达,以及Ki-67、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白表达均显著降低（均P<0.05）;细胞凋亡率、caspase-3蛋白表达均显著升高（均P<0.05）;740Y-P可部分逆转GKB对HGC-27细胞的抑制作用（均P<0.05）。荷瘤裸鼠实验结果显示,GKB可显著抑制HGC-27细胞裸鼠移植瘤的生长（P<0.05）,且可下调PI3K/Akt/mTOR通路相关蛋白的表达。结论：GKB可通过阻抑PI3K/Akt/mTOR信号通路而抑制胃癌HGC-27细胞增殖、迁移与侵袭并促进其凋亡。     

HK2通过Akt1/p-Akt1上调Cdc42表达促进宫颈癌细胞迁移和侵袭

目的:探究己糖激酶2（HK2）通过Akt1/p-Akt1/Cdc42促进宫颈癌细胞迁移和侵袭的作用机制。方法:G418压力筛选并获取稳定表达HK2蛋白的HeLa和SiHa细胞系;Western blot和细胞免疫化学鉴定HK2蛋白在HeLa和SiHa细胞系中的表达水平;细胞划痕实验检测HK2对HeLa和SiHa体外划痕愈合能力的影响;Transwell迁移、侵袭实验检测HK2对HeLa和SiHa细胞体外迁移和侵袭能力的影响;GEPIA数据库分别分析宫颈癌中HK2的表达与Akt1、Cdc42表达的相关性;Western blot检测Akt1、p-Akt1、Cdc42蛋白在HK2过表达的HeLa细胞和SiHa细胞中的表达情况;在HK2过表达的HeLa、SiHa细胞中应用Akt1/p-Akt1抑制剂MK2206观察Cdc42的表达及细胞迁移和侵袭能力的变化。结果:成功构建HK2稳定表达的HeLa、SiHa细胞系;过表达HK2促进了HeLa、SiHa细胞的划痕愈合能力,促进了HeLa、SiHa细胞的体外迁移和侵袭;GEPIA在线数据库结果显示在宫颈癌中HK2表达与Akt1、Cdc42表达均呈正相关;过表达HK2上调了Akt1、p-Akt1、Cdc42蛋白在HeLa、SiHa细胞中的表达;在HK2过表达HeLa、SiHa细胞中,MK2206的使用抑制了HK2对Cdc42表达上调及细胞迁移和侵袭的促进作用。结论:HK2可能通过Akt1/p-Akt1途径上调Cdc42蛋白的表达促进HeLa和SiHa细胞的迁移和侵袭。     

高迁移率族蛋白1及晚期糖基化终产物受体在宫颈鳞状细胞癌中的表达及临床意义

目的 研究高迁移率族蛋白1(HMGB1)和晚期糖基化终产物受体(RAGE)在宫颈鳞状细胞癌(CSCC)组织中的表达及其与临床病理间的关系,探讨HMGB1/RAGE信号通路在CSCC转移中的作用.方法 采用荧光实时定量PCR、免疫组化及Western blot方法分别检测CSCC组织和正常宫颈鳞状上皮组织中HMGB1、RAGE基因及蛋白的表达.结果HMGB1在CSCC中的表达水平高于正常宫颈鳞状上皮组织(P＜0.05),其在CSCC组织中的表达与肿瘤分期、侵袭及转移明显相关(P＜0.05),而与肿瘤大小、分化程度无关(P＞0.05).RAGE mRNA的表达与CSCC转移明显相关(P＜0.05).转移组中的HMGB1 mRNA和RAGE mRNA表达水平呈显著相关性.结论 HMGB-1与CSCC发生、侵袭和转移相关,RAGE与CSCC转移相关,HMGB1/RAGE信号通路在CSCC转移过程中可能发挥重要作用.     

2-Methoxyestradiol attenuates phosphatidylinositol 3-kinase/Akt pathway-mediated metastasis of gastric cancer

The major obstacle for the treatment of gastric cancer is recurrence and metastasis; yet, its molecular mechanism is largely unknown. 2-methoxyestradiol (2-ME), a metabolite of the estradiol-17beta, has recently been demonstrated to have multifactorial effects against tumor proliferation and angiogenesis; how these effects are interrelated and act cooperatively is the key question to be elucidated. Akt activation was shown to promote cancer cell invasiveness, and inhibition of Akt phosphorylation by 2-ME was also noted. We herein investigated the significance of PI3K/Akt activation in gastric cancer metastasis and the anti-metastatic effect of 2-ME through attenuation of Akt activity. Immunohistochemistry of PI3K, phosphorylated Akt (p-Akt) and phosphorylated Erk (p-Erk) was performed in tumors from 56 gastric cancer patients, and a significant correlation between PI3K/p-Akt and tumor stage/prognosis was demonstrated (p < 0.05). An in vitro study of 7 gastric cancer cell lines showed a remarkable correlation between PI3K and p-Akt. PI3K/p-Akt overexpression was associated with invasiveness/migration; in contrast, phosphorylation of Erk was not shown to be correlated with invasiveness. In addition, metastatic gastric cancer clones expressed a higher level of PI3K/p-Akt. The anti-metastatic effect of a low dose of 2-ME and inactivation of Akt was demonstrated. 2-ME also exhibited an ability to inhibit gastric cancer cell proliferation and induce G2/M cell cycle arrest at a higher concentration than that required for inhibition of migration. We conclude that the activation of PI3K/Akt pathway is involved in the late-stage progression and metastasis of gastric cancer, and attenuation of p-Akt by 2-ME suppresses metastasis.     

下调RAGE对膀胱癌T24细胞增殖、凋亡能力及周期分布的影响

目的:探究下调晚期糖基化终末产物受体(RAGE)对膀胱癌T24细胞增殖、凋亡能力及周期分布的影响.方法:人膀胱癌T24细胞株培养后,通过慢病毒载体构建下调RAGE组、上调RAGE组.MTT检测细胞增殖能力,流式细胞仪检测细胞凋亡、周期分布情况,Transwell小室实验检测各组细胞侵袭能力,通过细胞划痕实验检测各组细胞...     

RAGE和HMGB1在乳腺癌中表达及其临床意义

目的探讨乳腺癌组织中RAGE和HMGB1基因表达及其临床意义。方法各对50例早期、晚期乳腺癌组织及正常乳腺组织蜡块标本,运用real-time PCR技术检测RAGE和HMGB1基因的表达情况。并分析各基因表达与乳腺癌组织的分化程度、浸润深度、淋巴结转移、TNM分期之间的关系。结果 RAGE和HMGB1基因表达荧光实时定量PCR法上调分别为73%、79%。乳腺癌TNM分期、淋巴结转移与基因高表达有密切关系,RAGE基因表达与HMGB1表达呈正相关(P<0.05)。结论 RAGE和HMGB1基因表达对于乳腺癌早期诊断和预后分析有重要指导意义,根据其表达开展有选择性地基因治疗应有良好的应用前景。     

sRAGE及RAGE在胃癌患者中的临床意义分析

目的探讨与分析血清可溶性晚期糖基化终末产物受体(sRAGE)及RAGE在胃癌患者中的临床意义。方法选择手术切除的78例胃癌患者(胃癌组)与78例胃良性肿瘤患者(良性组),采用免疫组化法检测RAGE表达水平,采用酶联免疫法检测sRAGE表达水平。结果胃癌组的sRAGE表达水平显著高于良性组(P<0.05)。胃癌组的RAGE表达阳性率为83.3%,显著高于良性组的20.5%(P<0.05)。在胃癌组中,sRAGE表达水平与临床分期、肿瘤直径、浆膜浸润、组织学分化程度等有显著相关性(P<0.05);logistic分析显示临床分期、肿瘤直径、浆膜浸润为影响患者RAGE表达阳性率的主要因素(P<0.05)。结论胃癌患者血液中sRAGE呈现高表达,组织中RAGE表达阳性率高,与患者的临床分期、肿瘤直径、浆膜浸润、组织学分化程度等显著相关。     

Co-expression of RAGE and HMGB1 is associated with cancer progression and poor patient outcome of prostate cancer

Receptor for advanced glycation end products (RAGE), along with its ligand high mobility group box 1 (HMGB1), is believed to play an important role in prostate cancer. The aim of this retrospective study was to investigate the expression of RAGE and HMGB1 and their clinical impact on prostate cancer progression and prognosis. The expression of RAGE and HMGB1 was assessed by immunohistochemistry in cancer lesions from 85 confirmed prostate cancer cases. We determined the potential association between the expression level of these two proteins and the clinicopathological features and overall patient survival. RAGE and HMGB1 were expressed in 78.8% (67/85) and 68.2% (58/85) cases of prostate cancer, respectively, and in the majority (54/85) of cases, these two proteins were co-expressed. There was a strong correlation between RAGE and HMGB1 expressions (P<0.001). The expression of RAGE, HMGB1 and their co-expression were all associated with advanced tumor clinical stage (P<0.05 for all). RAGE expression was also associated with the prostate specific antigen (PSA) level (P=0.014). However, neither the individual expression of those genes nor their co-expression was significantly related with age or Gleason score. The co-expression of RAGE and HMGB1 was associated with poor overall survival in patients with stage III and IV prostate cancer (P=0.047). These results suggest that the expression of RAGE and HMGB1 is associated with the progression and poor prognosis of prostate cancer. RAGE and HMGB1 could be new prognostic biomarkers for prostate cancer as well as molecular target for novel forms of therapies.     

Bcl-w promotes gastric cancer cell invasion by inducing matrix metalloproteinase-2 expression via phosphoinositide 3-kinase, Akt, and Sp1

Given a previous report that Bcl-w is expressed in gastric cancer cells, particularly in those of an infiltrative morphology, we investigated whether Bcl-w expression influences the invasiveness of gastric cancer cells. To accomplish this, Bcl-w was overexpressed in adherent types of gastric adenocarcinoma cell lines, and this was found to result in an increase in their migratory and invasive potentials. These effects were not induced when Bcl-2 was overexpressed in the same cell types. Consistently, Bcl-w, but not Bcl-2, overexpression increased matrix metalloproteinase-2 (MMP-2) expression, and synthetic or natural inhibitors of MMP-2 abolished Bcl-w-induced cell invasion. Bcl-w overexpression also activated phosphoinositide 3-kinase (PI3K), Akt, and Sp1, and the blocking effects of each of these components using pharmacologic inhibitors, dominant-negative mutants, or small interfering RNA abolished the ability of Bcl-w to induce MMP-2 and cell invasion. The inhibition of PI3K/Akt signaling also prevented Sp1 activation. Overall, our data suggest that Bcl-w, which was previously shown to enhance gastric cancer cell survivability, also promotes their invasiveness by inducing MMP-2 expression via the sequential actions of PI3K, Akt, and Sp1.     

Expression of an activated mammalian target of rapamycin in adenocarcinoma of the cervix: A potential biomarker and molecular target therapy

Alterations of the Akt/mTOR pathway have been observed in numerous types of cancer, thus this pathway represents an exciting new target for molecular therapeutics. We investigated the expression of activated Akt (p-Akt) and mTOR (p-mTOR) in patients with adenocarcinoma of the cervix and the involvement of the p-Akt/p-mTOR pathway in response to combination of inhibitor agents, rapamycin and LY294002, with conventional therapy, cisplatin, in vitro. Immunohistochemistry analysis of p-Akt and p-mTOR was conducted in 26 patients with adenocarcinoma of the cervix. Western blot analysis was performed to determine the protein expression involved in response to chemotherapy in cervical cancer cell lines. The results showed that p-Akt and p-mTOR were identified in 50% and 53.8% of adenocarcinoma of the cervix. The expression of p-mTOR was a significant independent marker for prognosis. A significant correlation between p-Akt and p-mTOR was observed. There was no correlation between their expressions with any of clinicopathological factors. In the in vitro study, cisplatin at CPI(50) targets both the apoptosis and survival pathway by activating the caspase-cascade; inhibiting Akt, mTOR, p70S6K, and 4EBP1. Combination of rapamycin with cisplatin induced synergistic interaction. On the other hand, combination with LY294002 resulted in either synergistic or antagonistic effect depending on the doses given. Rapamycin pretreatment potentiated cisplatin-induced apoptosis cell death and enhanced blocking of the survival pathway. Overall, the expression of p-mTOR is a significant prognostic marker of adenocarcinoma of the cervix and a potential molecular target for the treatment of cervical cancer. Inhibition of the mTOR pathway contributes to cisplatin-induced apoptosis in cervical cancer cell lines.     

Targeting EMP3 suppresses proliferation and invasion of hepatocellular carcinoma cells through inactivation of PI3K/Akt pathway

Epithelial membrane protein-3 (EMP3), a typical member of the epithelial membrane protein (EMP) family, is epigenetically silenced in some cancer types, and has been proposed to be a tumor suppressor gene. However, its effects on tumor suppression are controversial and its roles in development and malignancy of hepatocellular carcinoma (HCC) remain unclear. In the present study, we found that EMP3 was highly expressed in the tumorous tissues comparing to the matched normal tissues, and negatively correlated with differentiated degree of HCC patients. Knockdown of EMP3 significantly reduced cell proliferation, arrested cell cycle at G1 phase, and inhibited the motility and invasiveness in accordance with the decreased expression and activity of urokinase plasminogen activator (uPA) and matrix metalloproteinase 9 (MMP-9) in HCC cells. The in vivo tumor growth of HCC was effectively suppressed by knockdown of EMP3 in a xenograft mouse model. The EMP3 knockdown-reduced cell proliferation and invasion were attenuated by inhibition of phosphatidylinositol 3-kinase (PI3K) or knockdown of Akt, and rescued by overexpression of Akt in HCC cells. Clinical positive correlations of EMP3 with p85 regulatory subunit of PI3K, p-Akt, uPA, as well as MMP-9 were observed in the tissue sections from HCC patients. Here, we elucidated the tumor progressive effects of EMP3 through PI3K/Akt pathway and uPA/MMP-9 cascade in HCC cells. The findings provided a new insight into EMP3, which might be a potential molecular target for diagnosis and treatment of HCC.