Inhibition of NEDD4 inhibits cell growth and invasion and induces cell apoptosis in bladder cancer cells

The neural precursor cell expressed developmentally downregulated protein 4 (NEDD4) plays a pivotal oncogenic role in various types of human cancers. However, the function of NEDD4 in bladder cancer has not been fully investigated. In the present study, we aim to explore whether NEDD4 governs cell proliferation, apoptosis, migration, and invasion in bladder cancer cells. Our results showed that downregulation of NEDD4 suppressed cell proliferation in bladder cancer cells. Moreover, we found that inhibition of NEDD4 significantly induced cell apoptosis. Furthermore, downregulation of NEDD4 retarded cell migration and invasion. Notably, overexpression of NEDD4 enhanced cell growth and inhibited apoptosis. Consistently, upregulation of NEDD4 promoted cell migration and invasion in bladder cancer cells. Mechanically, our Western blotting results revealed that downregulation of NEDD4 activated PTEN and inhibited Notch-1 expression, whereas upregulation of NEDD4 reduced PTEN level and increased Notch-1 level in bladder cancer cells. Our findings indicated that NEDD4 exerts its oncogenic function partly due to regulation of PTEN and Notch-1 in bladder cancer cells. These results further revealed that targeting NEDD4 could be a useful approach for the treatment of bladder cancer.     

Long noncoding RNA DLX6-AS1 promotes liver cancer by increasing the expression of WEE1 via targeting miR-424-5p

Long noncoding RNAs (lncRNAs) played an important role in tumorigenesis and development of hepatocellular carcinoma (HCC). In this study, we first demonstrated that lncRNA DLX6 antisense RNA 1 (DLX6-AS1) was upregulated in cancer tissues and cells lines compared with normal adjacent and cell line. Knock-down DLX6-AS1 by transfection with small interfering RNA (siRNA) suppressed cell proliferation, migration, and invasion of HCC cells. Cell cycle analysis showed that cells transfected with siRNA were arrested in G0/G1 phase. Then, we performed dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay to show that DLX6-AS1 could bind with miR-424-5p. And cotransfection inhibitor of miR-424-5p with siRNA of DLX6-AS1 could abolish the inhibitory effect of siRNA of DLX6-AS1 on cell proliferation, migration, and invasion. Moreover, we further demonstrated that the oncogene WEE1 G2 checkpoint kinase (WEE1) was the target of miR-424-5p and expression levels of WEE1 were positive correlation with that of DLX6-AS1. Taken together, these results suggested that upregulated DLX6-AS1 promoted cell proliferation, migration, and invasion of HCC through increasing expression of WEE1 via targeting miR-424-5p.     

Downregulation of integrin-linked kinase inhibits epithelial-to-mesenchymal transition and metastasis in bladder cancer cells

Integrin-linked kinase (ILK) is a multifunctional serine/threonine kinase in cytoplasm. Recent studies showed that cancer patients with increased ILK expression had low survival, poor prognosis and increased metastasis. Although the causes of ILK overexpression remain to be fully elucidated, accumulating evidence suggests that its oncogenic capacity derives from its regulation of several downstream targets that provide cells with signals that promote proliferation, survival and migration. However, the mechanisms underlying tumor metastasis by ILK is still not fully understood. Epithelial–mesenchymal transition (EMT) is a critical event of cancer cells that triggers invasion and metastasis. We recently reported that knockdown of ILK inhibited the growth and induced apoptosis in human bladder cancer cells. Therefore, we postulate that ILK might involve in EMT. Here we further investigate the function of ILK with RNA interference in bladder cancer cells. Knockdown of ILK impeded an EMT with low Vimentin, Snail, Slug and Twist as well as high E-cadherin expression in vivo and vitro. In addition, we found that knockdown of ILK inhibited cell proliferation, migration and invasion as well as changed cell morphology, adhesion and rearranged cytoskeleton in vitro. We also demonstrated that ILK siRNA inhibited phosphorylation of downstream signaling targets Akt and GSK3β, increased expression of nm23-H1, as well as reduced expression of MMP-2 and MMP-9 in vivo and vitro. Furthermore, downregulation of ILK could increase expression of Ribonuclease inhibitor (RI), an important acidic cytoplasmic protein with many functions. Finally, the effects of ILK siRNA on bladder cancer cell phenotype and invasiveness translate into suppression for tumorigenesis and metastasis in vivo. Taken together, our findings highlight that ILK signaling pathway plays a novel role in the development of bladder cancer through regulating EMT. ILK could be a promising diagnostic marker and therapeutic target for bladder cancer.     

The enhanced expression of estrogen-related receptor α in human bladder cancer tissues and the effects of estrogen-related receptor α knockdown on bladder cancer cells

Estrogen-related receptor α (ERRα) belongs to the superfamily of nuclear orphan receptors. However, the role of ERRα in bladder cancer remains unknown. This study examined the expression of ERRα in bladder cancer tissues and explored the molecular mechanisms of ERRα in bladder cancer progression. The expression of ERRα in bladder cancer tissues from 61 patients was determined by immunohistochemistry. We performed quantitative real-time polymerase chain reaction assay to detect the gene expression levels and carried out Western blot assay to measure protein levels. In vitro functional assays, including colony formation, Cell Counting Kit-8, Transwell invasion, and migration assays, were performed to detect bladder cancer cell growth, proliferation, invasion, and migration, respectively. Flow cytometry was used to determine the cell apoptotic rate of bladder cancer cells. Among the 61 detected bladder cancer tissues, 39 bladder cancer tissues showed positive ERRα immunoreactivity. Higher ERRα immunoreactivity score was significantly associated with TNM stage, tumor grade, distant metastasis, and poor survival in patients with bladder cancer. Univariate and multivariate analyses showed that ERRα immunoreactivity was an independent prognostic factor for overall survival in patients with bladder cancer. ERRα was found to be upregulated in bladder cancer cell lines, and knockdown of ERRα suppressed bladder cancer cell growth, proliferation, invasion, and migration; promoted bladder cancer cell apoptosis; and inhibited the epithelial-mesenchymal transition of bladder cancer cells. On the other hand, bladder cancer cell proliferation, invasion, and migration were significantly enhanced after cells were transfected with an ERRα-overexpressing vector. In vivo tumor growth and metastasis assays showed that ERRα knockdown resulted in remarkable inhibition of tumor growth and tumor metastasis in nude mice. Collectively, our results suggest that the enhanced expression of ERRα may play a key role in the development and progression of bladder cancer and ERRα may serve as an important prognostic factor for bladder cancer.     

MicroRNA-214 Suppresses Oncogenesis and Exerts Impact on Prognosis by Targeting PDRG1 in Bladder Cancer

MicroRNA-214 (miR-214) has been reported to be dysregulated in human bladder cancer tissues. We aimed to investigate the clinical correlation, biological significance and molecular network of miR-214 in bladder cancer. Our results showed miR-214 was down-regulated in bladder cancer tissues and significantly associated with tumor stage, lymph node status, grade, multifocality, history of non-muscle-invasive bladder cancer (NMIBC). Moreover, miR-214 could serve as an independent factor of recurrence-free survival (RFS) and overall survival (OS) for patients with muscle-invasive bladder cancer (MIBC). Restoration of miR-214 expression in bladder cancer cell lines inhibited cell proliferation, migration, invasion and markedly promoted apoptosis. Dual-luciferase reporter assay recognized PDRG1 as direct downstream target gene of miR-214. PDRG1 was significantly increased in tumors low of miR-214 and knockdown of PDRG1 mimicked the effects of miR-214 overexpression. Our findings manifest that miR-214 could exert tumor-suppressive effects in bladder cancer by directly down-regulating oncogene PDRG1 and suggest an appealing novel indicator for prognostic and therapeutic intervention of bladder cancer.     

下调脂肪酸合成酶表达对膀胱癌UMUC3细胞增殖、迁移及侵袭能力的影响*

目的: 研究脂肪酸合成酶(FASN)表达对膀胱癌UMUC3细胞增殖、迁移、侵袭的影响,探讨其内在可能机制。方法:免疫组化法检测30例膀胱癌和15例正常膀胱组织FASN蛋白的表达;用脂质体2000分别转染FASN siRNA和无义siRNA至UMUC3细胞,筛选、鉴定siFASN和siControl稳定的细胞,siFASN组细胞设为实验组,siControl组设为对照组;采用蛋白印迹法(Western blot)和实时荧光定量PCR(RT-PCR)法分别检测siFASN组和siControl组细胞FASN蛋白及mRNA的表达,MTT法检测siFASN组和siControl组细胞增殖情况,划痕试验、Transwell试验分别检测siFASN组和siControl组细胞迁移、侵袭能力。结果:FASN蛋白在膀胱癌组织中过表达,且与病理分期、分级密切相关(P＜0.05)。与siControl组相比,siFASN组细胞FASN mRNA及蛋白表达下调(P＜0.05),细胞增殖活力明显下降(P＜0.05),迁移能力明显下降(P＜0.05),穿膜细胞数量明显减少(P＜0.05)。结论:FASN过表达在膀胱癌发生、发展中发挥重要作用,下调FASN表达能抑制膀胱癌细胞的增殖、迁移、侵袭能力,抑制FASN表达有望成为一种新的膀胱癌治疗方法。     

Retracted: LncRNA MT1JP functions as a tumor suppressor via regulating miR-214-3p expression in bladder cancer

Growing evidence suggested that the long noncoding RNAs (lncRNAs) regulate several pathophysiological processes in tumorigenesis and may be new biomarkers for tumor therapy. In this study, we studied the expression and role of lncRNA MT1JP in the development of bladder cancer. We demonstrated that the expression of MT1JP was downregulated in bladder tumor samples and cell lines. Ectopic expression of MT1JP suppressed cell proliferation, cycle, and invasion in bladder cancer. In addition, our result suggested that miR-214-3p overexpression decreased the luciferase activity of wild-type MT1JP but not mutated-type MT1JP and elevated expression of MT1JP decreased miR-214-3p expression in the bladder cancer cell. Furthermore, we indicated that the expression of miR-214-3p was upregulated in bladder tumor samples and cell lines. Ectopic expression of miR-214-3p promoted cell proliferation, cycle, and invasion in bladder cancer. MT1JP suppressed cell proliferation, cycle, and invasion via negative modulation of miR-214-3p in bladder cancer. These data suggested that lncRNA MT1JP acts a tumor suppressor gene in bladder cancer progression, considering MT1JP as a new therapeutic target in bladder cancer.     

MiR-1266 promotes cell proliferation,migration and invasion in cervical cancer by targeting DAB2IP

Cervical cancer (CC) is one of the most prevalent cancers in women in the world. However, the pathogenesis is still very unclear, and the current screening methods are too expensive. Emerging evidence shows that miR-1266 has great influence on tumor cell migration and invasion. In order to clarify the role of miR-1266 in CC, we collected serum from CC, high-grade squamous intraepithelial lesion (HSIL), low-grade squamous intraepithelial lesion (LSIL) and normal control (NC), collected tissues from CC and control group (CG), and followed up 50 CC patients. We used HeLa and SiHa cells to clarify the roles of miR-1266 on cell proliferation, migration and invasion. The CC mouse model was conducted to prove the role of miR-1266 on tumorigenesis. qRT-PCR was used to measure the expressions of miR-1266 and DAB2IP mRNA. Western blot was used to determine the expression of DAB2IP protein. Cell counting kit-8 proliferation assay (CCK-8), Colony formation assay, Wound-healing assay and Transwell invasion assay were used to determine the cell survival, proliferative, migrative and invasive abilities. Our study found that miR-1266 had a rising trend in serum from NC to LSIL to HSIL to CC, and increased in CC tissues. High expression serum miR-1266 had lower overall survival rates than patients with miR-1266 low expression. MiR-1266 promoted cell viability, proliferation, migration and invasion by targeting DAB2IP. And miR-1266 could promote tumorigenesis in vivo. In conclusion, miR-1266 could be used as a new biomarker for diagnosis, prediction and treatment of CC in the future.     

SATB1 Overexpression Regulates the Development and Progression in Bladder Cancer through EMT

The global gene regulator Special AT-rich sequence-binding protein-1 (SATB1) has been reported to induce EMT-like changes and be associated with poor clinical outcome in several cancers. This study aims to evaluate whether SATB1 affects the biological behaviors of bladder transitional cell carcinoma (BTCC) and further elucidate if this effect works through an epithelial-mesenchymal transition (EMT) pathway. The expression of SATB1, E-cadherin (epithelial markers), vimentin (mesenchymal markers) in BTCC tissues and adjacent noncancerous tissues, as well as in two cell lines of bladder cancer were investigated. Whether the SATB1 expression is associated with clinicopathological factors or not was statistically analyzed. Cell invasion and migration, cell cycle, cell proliferation and apoptosis were evaluated in SATB1 knockdown and overexpressed cell lines. Our results showed that the expression of SATB1 was remarkably up-regulated both in BTCC tissues and in bladder cancer cell lines with high potential of metastasis. The results were also associated with EMT markers and poor prognosis of BTCC patients. Moreover, SATB1 induced EMT processes through downregulation of E-cadherin, upregulation of E-cadherin repressors (Snail, Slug and vimentin). SATB1 also promoted cell cycle progression, cell proliferation, cell invasion and cell migration, but did not alter cell survival. In conclusion, our results suggest that SATB1 plays a crucial role in the progression of bladder cancer by regulating genes controlling EMT processes. Further, it may be a novel therapeutic target for aggressive bladder cancers.     

lncRNA MIR503HG functioned as a tumor suppressor and inhibited cell proliferation,metastasis and epithelial-mesenchymal transition in bladder cancer

Bladder cancer is the most common malignancy with high recurrence. Currently, the long noncoding RNAs (lncRNAs) have been suggested to play vital roles in the pathogenesis of bladder cancer. The present study investigated the role of lncRNA MIR503 host gene (MIR503HG) in the pathogenesis of bladder cancer by using both in vitro and in vivo functional assays. The expression of MIR503HG was downregulated in bladder cancer tissues and cell lines. Low expression of MIR503HG was associated with advanced tumor stage, advanced histological grade, and lymph node metastasis. Ectopic expression of MIR503HG inhibited cell proliferation, cell growth, cell invasion, and migration, and also promoted cell apoptosis and inhibited cell cycle progression in SW780 cells. In parallel, T24 cells were used for loss-of-function studies. Knockdown of MIR503HG promoted the cancer cell proliferation and increased the migration and invasion abilities of T24 cells. In addition, knockdown of MIR503HG reduced the cell apoptotic rate in cancer cells and promoted cell cycle progression. Furthermore, MIR503HG overexpression decreased the epithelial-mesenchymal transition-related mRNA and protein levels of ZEB1, Snail, N-cadherin, and vimentin, with an increase in E-cadherin level. Consistently, knockdown of MIR503HG showed the opposite effects. In vivo xenograft, nude mice results showed that overexpression of MIR503HG suppressed the tumor growth and tumor metastasis. In conclusion, our results identified a novel lncRNA MIR503HG that exhibited significant antiproliferation, antimigration/invasion effects on bladder cancer cells both in vitro and in vivo, which may hold a therapeutic promise to treat bladder cancer.     

miR-302通过下调靶基因RAB22A抑制膀胱癌进展

目的:探讨miR-302通过靶向调控RAB22A影响膀胱癌进展的分子机制。方法:采用RT-qPCR检测miR-302在HTB1和RT112膀胱癌细胞系和膀胱内皮细胞系HBdNEC中的表达;以miRNA-NC、miR-302 mimic、miR-302 inhibitor转染细胞,并分为以下几组:NC+control si RNA、miR-302 inhibitor+control si RNA、miR-302 inhibitor+RAB22A si RNA、NC+vector、miR-302 mimic+vector或miR-302 mimic+RAB22A,再通过MTT实验分析膀胱癌细胞的增殖情况,细胞侵袭实验检测细胞侵袭情况,双荧光素酶报告载体检测分析miR-302靶基因,Western blot检测RAB22A在膀胱癌细胞中的表达。结果:HTB1和RT112细胞中miR-302的表达明显低于HBdNEC细胞(P0.05)。miR-302高表达抑制膀胱癌细胞的增殖和侵袭;miR-302低表达时,膀胱癌细胞的增殖和侵袭能力上升。生物信息学和双荧光素酶报告结果显示RAB22A为miR-302的靶基因。miR-302过表达后,细胞荧光素酶活性显著下降(P0.05),RAB22A表达下调(P0.05);miR-302表达沉默后,细胞荧光素酶活性显著上升(P0.05),RAB22A表达上调(P0.01)。拯救实验显示RAB22A表达沉默可逆转miR-302表达沉默时对膀胱癌细胞增殖和侵袭能力上调的影响;而RAB22A过表达可逆转miR-302过表达对膀胱癌细胞增殖和侵袭的抑制。结论:miR-302可通过抑制靶基因RAB22A的表达,抑制膀胱癌细胞的增殖及侵袭。     

Curcumin inhibits the growth of triple‐negative breast cancer cells by silencing EZH2 and restoring DLC1 expression

Enhancer of zeste homolog 2 (EZH2), an oncogene, is a commonly up‐regulated epigenetic factor in human cancer. Hepatocellular carcinoma deletion gene 1 (DLC1) is an antioncogene that is either expressed at low levels or not expressed in many malignant tumours. Curcumin is a promising anticancer drug that has antitumour effects in many tumours, but its mechanism of action is unclear. Our research demonstrated that EZH2 was up‐regulated in breast cancer (BC) tissues and cells, whereas DLC1 was down‐regulated, and the expression of EZH2 and DLC1 was negatively correlated in BC. By analysing the characteristics of clinical cases, we found that positive expression of EZH2 and negative expression of DLC1 may be predictors of poor prognosis in patients with triple‐negative breast cancer (TNBC). Moreover, knockdown of EZH2 expression restored the expression of DLC1 and inhibited the migration, invasion and proliferation, promoted the apoptosis, and blocked the cell cycle of MDA‐MB‐231 cells. Furthermore, we found that curcumin restored the expression of DLC1 by inhibiting EZH2; it also inhibited the migration, invasion and proliferation of MDA‐MB‐231 cells, promoted their apoptosis and blocked the cell cycle. Finally, xenograft tumour models were used to demonstrate that curcumin restored DLC1 expression by inhibiting EZH2 and also inhibited the growth and promoted the apoptosis of TNBC cells. In conclusion, our results suggest that curcumin can inhibit the migration, invasion and proliferation, promote the apoptosis, block the cycle of TNBC cells and restore the expression of DLC1 by inhibiting the expression of EZH2.     

Over-expression of LSD1 promotes proliferation, migration and invasion in non-small cell lung cancer

Background

Lysine specific demethylase 1 (LSD1) has been identified and biochemically characterized in epigenetics, but the pathological roles of its dysfunction in lung cancer remain to be elucidated. The aim of this study was to evaluate the prognostic significance of LSD1 expression in patients with non-small cell lung cancer (NSCLC) and to define its exact role in lung cancer proliferation, migration and invasion.

Methods

The protein levels of LSD1 in surgically resected samples from NSCLC patients were detected by immunohistochemistry or Western blotting. The mRNA levels of LSD1 were detected by qRT-PCR. The correlation of LSD1 expression with clinical characteristics and prognosis was determined by statistical analysis. Cell proliferation rate was assessed by MTS assay and immunofluorescence. Cell migration and invasion were detected by scratch test, matrigel assay and transwell invasion assay.

Results

LSD1 expression was higher in lung cancer tissue more than in normal lung tissue. Our results showed that over-expression of LSD1 protein were associated with shorter overall survival of NSCLC patients. LSD1 was localized mainly to the cancer cell nucleus. Interruption of LSD1 using siRNA or a chemical inhibitor, pargyline, suppressed proliferation, migration and invasion of A549, H460 and 293T cells. Meanwhile, over-expression of LSD1 enhanced cell growth. Finally, LSD1 was shown to regulate epithelial-to-mesenchymal transition in lung cancer cells.

Conclusions

Over-expression of LSD1 was associated with poor prognosis in NSCLC, and promoted tumor cell proliferation, migration and invasion. These results suggest that LSD1 is a tumor-promoting factor with promising therapeutic potential for NSCLC.     

Exploring the five different genes associated with PKCα in bladder cancer based on gene expression microarray

Much progress has been made in understanding the mechanism of bladder cancer (BC) progression. Protein kinase C-α (PKCα) is overexpressed in many kinds of cancers. Additionally, PKCα is considered an oncogene that regulates proliferation, invasion, migration, apoptosis and cell cycle in multiple cancers. However, the mechanism underlying how these cellular processes are regulated by PKCα remains unknown. In the present study, we used PKCα siRNA to knock down PKCα gene expression and found that down-regulation of PKCα could significantly inhibit cell proliferation, migration and invasion and induce apoptosis and G1/S cell cycle arrest in vitro. Overexpression of PKCα promotes tumour growth in vivo. We applied cDNA microarray technology to detect the differential gene expression in J82 cells with PKCα knockdown and found that five key genes (BIRC2, BIRC3, CDK4, TRAF1 and BMP4) were involved in proliferation and apoptosis according to GO analysis and pathway analyses. Correlation analysis revealed a moderate positive correlation between PKCα expression and the expression of five downstream genes. BIRC2 and BIRC3 inhibit apoptosis, whereas CDK4, TRAF1 and BMP4 promote proliferation. Essentially, all five of these target genes participated in proliferation, and apoptosis was regulated by PKCα via the NF-kB signalling pathway.     

Fibronectin promotes cervical cancer tumorigenesis through activating FAK signaling pathway

Cervical cancer is a cancer arising from the cervix, and it is the fourth most common cause of death in women. Overexpression of fibronectin 1 (FN1) was observed in many tumors and associated with the survival and metastasis of cancer cells. However, the mechanism by which FN1 promotes cervical cancer cell viability, migration, adhesion, and invasion, and inhibits cell apoptosis through focal adhesion kinase (FAK) signaling pathway remains to be investigated. Our results demonstrated that FN1 was upregulated in patients with cervical cancer and higher FN1 expression correlated with a poor prognosis for patients with cervical cancer. FN1 knockdown by small interfering RNA (siRNA) inhibited SiHa cell viability, migration, invasion, and adhesion, and promoted cell apoptosis. FN1 overexpression in CaSki cell promoted cell viability, migration, invasion, and adhesion, and inhibited cell apoptosis. Further, phosphorylation of FAK, a main downstream signaling molecule of FN1, and the protein expression of Bcl-2/Bax, matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), and N-cadherin was upregulated in CaSki cells with FN1 overexpression, but caspase-3 protein expression was downregulated. The FAK phosphorylation inhibitor PF573228 inhibited FN1 overexpression-induced expression of those proteins in CaSki cells with FN1 overexpression. In vivo experiment demonstrated that FN1 knockdown significantly inhibited FN1 expression, phosphorylation of FAK, and tumor growth in xenograft from the nude mice. These results suggest that FN1 regulates the viability, apoptosis, migration, invasion, and adhesion of cervical cancer cells through the FAK signaling pathway and is a potential therapeutic target in the treatment of cervical cancer.     

CXCL5 knockdown expression inhibits human bladder cancer T24 cells proliferation and migration

CXCL5 (epithelial neutrophil activating peptide-78) which acts as a potent chemoattractant and activator of neutrophil function was reported to play a multifaceted role in tumorigenesis. To investigate the role of CXCL5 in bladder cancer progression, we examined the CXCL5 expression in bladder cancer tissues by real-time PCR and Western blot, additionally, we used shRNA-mediated silencing to generate stable CXCL5 silenced bladder cancer T24 cells and defined its biological functions. Our results demonstrated that mRNA and protein of CXCL5 is increased in human bladder tumor tissues and cell lines, down-regulation of CXCL5 in T24 cells resulted in significantly decreased cell proliferation, migration and increased cell apoptosis in vitro through Snail, PI3K-AKT and ERK1/2 signaling pathways. These data suggest that CXCL5 is critical for bladder tumor growth and progression, it may represent a potential application in cancer diagnosis and therapy.     

Role of PI3K and AKT specific isoforms in ovarian cancer cell migration, invasion and proliferation through the p70S6K1 pathway

Ovarian cancer is the leading cause of death from gynecological malignancy for women. The amplification of the PI3K catalytic subunit (p110) and the lost function of PTEN are frequently detected in ovarian cancer cells. PI3K plays an important role in tumorigenesis. To specifically inhibit PI3K activity in ovarian cancer cells, we constructed small interfering RNA (siRNA) against p110. The expression of p110 siRNA significantly decreased cell migration, invasion, and proliferation compared to the siSCR control cells. The expression of p110 siRNA induced CDK inhibitor p27^KIP1 levels, and decreased levels of cyclin D1, CDK4, and phosphorylated retinoblastoma protein. PI3K transmits the mytogenic signal through AKT. AKT has three isoforms in the cells: AKT1, AKT2 and AKT3. We found that inhibition of AKT1 is sufficient to affect cell migration, invasion, and proliferation. Expression of AKT1 siRNA had a similar effect as p110 siRNA in the cells. We showed the roles of specific PI3K and AKT isoforms in the cells, which are important to understanding the mechanism of PI3K/AKT signaling in ovarian cancer cells. Both p110 and AKT1 siRNA-expressing cells decreased the activation of p70S6K1. Inhibition of p70S6K1 activity by its siRNA also decreased cell migration, invasion, and proliferation associated with the induction of p27^KIP1 levels, and with the inhibition of cell cycle-associated proteins including cyclin D1, CDK2, and phosphorylated retinoblastoma protein. This study demonstrates the important role of the PI3K/AKT/mTOR/p70S6K1 pathway in cell proliferation, migration, and invasion in ovarian cancer cells by using siRNA-mediated gene silencing as a reverse genetic method.