Malignant Behaviors Of Colorectal Cancer Cells Research Articles

LncRNA PSMB8-AS1 promotes colorectal cancer progression through sponging miR-1299 to upregulate ADAMTS5.

Long non-coding RNAs (lncRNAs) have been reported to be vital participants in tumor progression. Recently, lncRNA PSMB8-AS1 has been uncovered to facilitate pancreatic cancer progression by regulating miR-382-3p/STAT1/PD-L1 network. Nonetheless, the role of PSMB8-AS1 and its underlying mechanism have not been well-explored in colorectal cancer (CRC). The expression of RNAs or proteins was detected via qRT-PCR or western blot assays. Functional assays were involved in evaluating the effects of PSMB8-AS1/miR-1299/ADAMTS5 on the malignant behaviors of CRC cells. The molecular mechanism of PSMB8-AS1 was explored via mechanism analyses in CRC cells. Based on experimental results, PSMB8-AS1 expression was notably higher in CRC cell lines than in normal cells. The downregulation of PSMB8-AS1 repressed cell viability, proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of CRC while promoting cell apoptosis. It was also revealed that PSMB8-AS1 could sponge miR-1299 to upregulate ADAMTS5 in CRC cells. In rescue assays, we further discovered that miR-1299 inhibition or ADAMTS5 overexpression abrogated the suppressive influence of PSMB8-AS1 deficiency on CRC cell growth. In addition, PSMB8-AS1 was validated to induce M2 polarization. In conclusion, PSMB8-AS1 sponges miR-1299 to increase PSMB8-AS1 expression, thus promoting CRC cell growth.

Reduced expression of microRNA-432-5p by DNA methyltransferase 3B leads to development of colorectal cancer through upregulation of CCND2

BackgroundThe tumor suppressive function of microRNA-432-5p (miR-432-5p) has been reported in several human malignances. This study aimed to probe the expression profile and role of miR-432-5p in colorectal cancer (CRC) and the molecular mechanism. MethodsDifferentially expressed miRNAs between CRC and healthy samples were screened using a miRNA expression dataset GSE136020. The related molecules were identified by integrated bioinformatic analyses. A murine model of primary CRC was established and xenograft tumors were induced in mice. Altered expression of DNMT3B, miR-432-5p and cyclin D2 (CCND2) were introduced in CRC cells to determine their roles in the development of CRC. ResultsmiR-432-5p was downregulated in CRC according to the GSE136020 dataset. CCND2 mRNA was confirmed as a target of miR-432-5p. miR-432-5p was downregulated, whereas CCND2 was abundantly expressed in CRC tissues and cells. DNA methyltransferase 3B (DNMT3B) induced DNA methylation at the CpG island of miR-432-5p to inhibit its expression. miR-432-5p mimic significantly suppressed tumorigenesis of primary CRC in mice. Downregulation of DNMT3B weakened viability, invasiveness, blocked the cell cycle progression of CRC cells in vitro, and inhibited xenograft tumor growth and metastasis in nude mice. However, additional downregulation of miR-432-5p or upregulation of CCND2 restored the malignant behaviors of CRC cells. ConclusionThis study showed that DNMT3B induced DNA methylation and downregulation of miR-432-5p to promote development of CRC by upregulating CCND2.

Circ_0029803 serves as the sponge of miR-216b-5p to promote the progression of colorectal cancer by regulating SKIL expression

BackgroundCircular RNA 0029803 (circ_0029803) was found to be upregulated in colorectal cancer (CRC) tissues, but its function and underlying molecular mechanism are not studied in CRC.MethodsThe expression levels of circ_0029803, microRNA-216b-5p (miR-216b-5p), and ski-oncogene-like (SKIL) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). RNase R treatment was used to affirm the existence of circ_0029803. Cell proliferation, apoptosis, migration, and invasion were assessed by colony formation, flow cytometry, and Transwell assays, respectively. A glucose and lactate assay kit was used to detect glucose consumption and lactate production. Western blot was applied to analyze the levels of all proteins. Dual-luciferase reporter assay was performed to assess the relationship between miR-216b-5p and circ_0029803 or SKIL. Tumor xenograft models were established to elucidate the effect of circ_0029803 in vivo.ResultsCirc_0029803 expression was enhanced in CRC tissues and cells, and the 5-year overall survival rate of patients with high circ_0029803 expression was substantially reduced. Circ_0029803 depletion retarded proliferation, migration, invasion, EMT and glycolysis of CRC cells in vitro as well as the tumor growth in vivo. Mechanically, circ_0029803 could serve as miR-216b-5p sponge to regulate its expression, and miR-216b-5p knockdown reversed the inhibition of si-circ_0029803 on the malignant behaviors of CRC cells. Additionally, as the target mRNA of miR-216b-5p, SKIL could counteract the inhibitory effect of miR-216b-5p on the development of CRC cells. Importantly, silencing circ_0029803 reduced SKIL expression via sponging miR-216b-5p.ConclusionCirc_0029803 knockdown hindered proliferation, migration, invasion, EMT, and glycolysis and promoted apoptosis in CRC cells by modulating the miR-216b-5p/SKIL axis.

CircTADA2A Retards the Progression of Colorectal Cancer via Regulating miR-1229/BCL2L10 Signal Axis.

BackgroundColorectal cancer (CRC) is one of the leading causes of cancer-related death around the world, becoming a severe public health problem. Mounting evidence has proven that circRNAs act as pivotal modulators in the initiation and development of CRC. Although the function of circTADA2A has been explored in osteosarcoma and breast cancer, the specific role of circTADA2A in CRC remains unknown.MethodsBioinformatics analysis based on GEO datasets was used to evaluate the dysregulated circRNAs in CRC. CCK-8 and transwell assays were used to detect the functions of CRC cells. qRT-PCR and Western blot were performed to evaluate the expression of RNAs and proteins. Luciferase assay and RNA pull down experiment were carried out to verify the interaction between miR and its targets.ResultsCircTADA2A was downregulated in CRC tissues compared with normal samples. CircTADA2A exhibited greater stability than its linear form when exposed to RNase R and actinomycin D treatment. qRT-PCR analysis validated the lower expression level of circTADA2A in CRC. The loss-of-function and gain-of-function assays indicated that circTADA2A exerted the inhibitory role in CRC cell proliferation and migration. Mechanistically, circTADA2A functioned as a sponge of miR-1229. Further experiments manifested that circTADA2A regulated BCL2L10 expression via competitively binding to miR-1229. More importantly, the tumor suppressor role of circTADA2A in the malignant behaviors of CRC cells was mediated by BCL2L10.ConclusioncircTADA2A suppressed cell proliferation and migration in CRC through regulation of miR-1229/BCL2L10 axis, which suggested that circTADA2A might represent a novel potential target for the treatment of CRC.

Isoflurane Suppresses Proliferation, Migration, and Invasion and Facilitates Apoptosis in Colorectal Cancer Cells Through Targeting miR-216

Objective: Surgery is the first line treatment of colorectal cancer (CRC). Anesthetic isoflurane may improve outcomes of cancer surgery. Herein, we investigated the effects of isoflurane on malignant behaviors of CRC cells and its underlying therapeutic target.Methods: SW620 and HCT116 CRC cells were exposed to a series of concentrations of isoflurane. CCK-8 assay was utilized for determination of the optimal concentration of isoflurane. Under treatment with isoflurane, proliferation, migration, and invasion were separately assessed via clone formation and transwell assays. Apoptotic levels were observed via flow cytometry and expression of Bax, Bcl-2, and Caspase3 proteins was quantified through western blot. MiR-216 expression was detected in isoflurane-induced SW620 and HCT116 cells by RT-qPCR. Following transfection with miR-216 mimic, malignant biological behaviors were examined in isoflurane-treated SW620 and HCT116 cells.Results: 40 μM isoflurane distinctly restrained proliferative, migrated, and invasive capacities and elevated apoptotic levels in SW620 and HCT116 cells. Up-regulation of miR-216 was found in CRC cells. Its expression was suppressed by isoflurane. MiR-216 mimic ameliorated the reduction in proliferation, migration, and invasion and the increase in apoptosis for 40 μM isoflurane-induced SW620 and HCT116 cells.Conclusion: Isoflurane, a promising drug of CRC, may suppress malignant biological behaviors of tumor cells. Furthermore, miR-216 is an underlying target of isoflurane. Thus, isoflurane could be adopted for CRC treatment.

MiR‑4306 inhibits the malignant behaviors of colorectal cancer by regulating lncRNA FoxD2‑AS1.

MicroRNA (miR)-4306 and FoxD2-adjacent opposite strand RNA 1 (FOXD2-AS1) are cancer-related genes involved in tumor progression. However, the potential functional roles of miR-4306 and FoxD2-AS1 in colorectal cancer (CRC) development remain unknown. The present study aimed to investigate the biological functions and the molecular mechanisms of miR-4306 and FoxD2-AS1 in CRC. Reverse transcription-quantitative PCR analysis was performed to determine the expression levels of FoxD2-AS1 and miR-4306 in CRC tissues and cell lines. Functional experiments, including Cell Counting Kit-8, colony formation, cell cycle assays and western blotting, were conducted to examine the effects of FoxD2-AS1 and miR-4306 on the malignant behaviors of CRC cells. In addition, the relationship between FoxD2-AS1 and miR-4306 was assessed using a dual-luciferase reporter assay and Pearson's correlation analysis. Compared with normal samples and cells, FoxD2-AS1 expression was increased and miR-4306 expression was decreased in CRC tissues and cells. Functional experiments demonstrated that silencing FoxD2-AS1 inhibited proliferation and induced cell arrest at G0/G1 phase in CRC cells, while the overexpression of FoxD2-AS1 showed opposite results. Ki-67 and proliferating cell nuclear antigen expression levels were decreased after transfection with small interfering RNA FoxD2-AS1, but were increased after transfection with FoxD2-AS1 overexpression plasmid. Furthermore, investigations into the underling mechanism revealed that FoxD2-AS1 functioned as a molecular sponge of miR-4306. The inhibitory effects of FoxD2-AS1 silencing on CRC progression were reversed by miR-4306 knockdown. Collectively, the present study demonstrated that FoxD2-AS1 functioned as an oncogene in CRC progression, and that miR-4306 could inhibit the malignant behaviors of CRC by regulating FoxD2-AS1. Thus, the current study provided a promising therapeutic target for CRC treatment.

LncRNA AFAP1-AS1 Promotes the Progression of Colorectal Cancer through miR-195-5p and WISP1.

Objective Colorectal cancer (CRC) is the most common cancer. But, the molecular mechanisms of CRC progression are not fully understood. This study was conducted to explore how the long noncoding RNA actin filament-associated protein 1-antisense RNA1 (lncRNA AFAP1-AS1) participates in CRC progression through the regulation of microRNA-195-5p (miR-195-5p) and wingless-type inducible signaling pathway protein-1 (WISP1). Methods The expressions of AFAP1-AS1, miR-195-5p, and WISP1 were detected by RT-qPCR or western blot. A dual-luciferase assay confirmed the target relationship of AFAP1-AS1, miR-195-5p, and WISP1. Colony formation, wound-healing, and Transwell assays were used to detect the growth, migration, and invasion abilities of cells, respectively. Results AFAP1-AS1 and WISP1 expressions were notably increased, and miR-195-5p expression was markedly reduced in CRC. The dual-luciferase assay verified that AFAP1-AS1 could bind to miR-195-5p. AFAP1-AS1 knockdown could inhibit the malignant behavior of CRC cells. miR-195-5p could target and regulate WISP1 expression. Overexpression of WISP1 or miR-195-5p inhibition reversed the inhibition effect of AFAP1-AS1 knockdown on the biological activity of CRC cells. Conclusions AFAP1-AS1 knockdown may inhibit the proliferation, migration, and invasion of CRC cells through the miR-195-5p/WISP1 axis.

RETRACTED: Inhibiting microRNA-424 in bone marrow mesenchymal stem cells-derived exosomes suppresses tumor growth in colorectal cancer by upregulating TGFBR3

ObjectiveMicroRNAs (miRNAs) have been demonstrated to be differently expressed in colorectal cancer (CRC) and were identified as biomarkers and therapeutic targets for CRC. We aimed to identify the effect of microRNA-424 (miR-424) on process of CRC. MethodsExosomes were obtained from bone marrow mesenchymal stem cells (BMSCs). MiR-424, transforming growth factor-β receptor 3 (TGFBR3) vimentin, S100A4, p-Smad1 expression in tissues and cells was measured. After treated with miR-424 inhibitor or TGFBR3 overexpression plasmid, the migration, invasion, cell cycle distribution and apoptosis of Lovo cells and exosomes-transfected Lovo cells were determined. The subcutaneous tumor models were established and the tumor growth was observed. The target relation between miR-424 and TGFBR3 was confirmed. ResultsMiR-424 was upregulated while TGFBR3 was downregulated in CRC tissues. TGFBR3 was targeted by miR-424. Inhibited miR-424 or elevated TGFBR3 upregulated p-Smad1, indicating that TGFBR3 mediated the Smad1 pathway, thus regulating CRC progression. MiR-424 inhibition or TGFBR3 restoration also suppressed migration and invasion of CRC cells, arrested the CRC cells at G0/G1 phase, and promoted CRC cell apoptosis. Moreover, exosomal miR-424 from BMSCs promoted CRC development. ConclusionInhibited exosomal miR-424 from BMSCs inhibited malignant behaviors of CRC cells by targeting TGFBR3, thus suppressing the progression of CRC.

Circular RNA circ_0000467 regulates colorectal cancer development via miR-382-5p/EN2 axis

ABSTRACT Circular RNAs (CircRNAs), belonging to non-coding RNAs, exert a crucial modulatory role in cancer progression. In this study, circRNA microarray analysis was utilized to screen differentially expressed circRNA in colorectal cancer (CRC) and circ_0000467 was identified as one circRNA whose expression was significantly upregulated in CRC. Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) indicated that circ_0000467 and engrailed-2 (EN2) expression levels were up-modulated, while the expression level of miR-382-5p was down-modulated in CRC tissues. The depletion of circ_0000467 expression was found to impede the multiplication, migration, invasion, and epithelial-mesenchymal transition (EMT) processes in CRC cells, which were examined by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and Transwell experiments. Dual-luciferase reporter assay was used to verify the targeting relationship between circ_0000467 and miR-382-5p. It was also revealed that circ_0000467 could up-regulate EN2 expression via repressing miR-382-5p in CRC cells. Furthermore, EN2 overexpression counteracted the suppressing effects of circ_0000467 knockdown on the malignant behaviors of CRC cells. To sum up, circ_0000467 facilitates CRC development by modulating the miR-382-5p/EN2 axis, and circ_0000467 is a promising target for CRC therapy.

Aberrant KIF23 expression is associated with adverse clinical outcome and promotes cellular malignant behavior through the Wnt/β-catenin signaling pathway in Colorectal Cancer.

Purpose: The aim of the present study was to reveal the clinicopathological significance and prognostic role of kinesin family member 23 (KIF23) in colorectal cancer (CRC) and characterize its biological function and the underlying mechanisms.Methods: Bioinformatics analysis, immunohistochemistry, Western blot and qRT-PCR were utilized to investigate the expression of KIF23 in CRC tissues. The CCK-8 assay, wound healing assay and Matrigel assay were used to detect cell proliferation, migration and invasion in vitro. Western blot, immunofluorescence staining and cell function experiment were performed to explore the underlying mechanism.Results: The overexpression of KIF23 was associated with T stage, N stage, M stage and TNM stage, and CRC patients with high KIF23 expression had a worse prognosis. KIF23 knockdown inhibits CRC cells proliferation, migration and invasion in vitro. The mechanism study determined that KIF23 activates the Wnt/β-catenin signaling pathway by promoting the nuclear translocation of β-catenin to regulate the malignant behavior of CRC cells.Conclusion: These results suggest that KIF23 may act as a putative oncogene and a potential therapeutic target in CRC.

MicroRNA-802 Suppresses Tumorigenesis of Colorectal Cancer via Regulating UBN2.

BackgroundThe initiation and progression of colorectal cancer (CRC) are a multistep complex process regulated by multiple factors. Previous evidence indicated that microRNA-802 (miR-802) participated in tumorigenesis of numerous solid cancers; however, the potential roles and underlying mechanisms of miR‑802 in CRC still need further exploration.MethodsQuantitative real-time PCR (qRT-PCR) was employed to evaluate miR-802 levels in human CRC tissues and cell lines. In vitro proliferation, apoptosis, migration and invasion assays, and in vivo subcutaneous mouse xenograft model were utilized to examine the effects of miR-802 on the malignant behaviors of CRC cells. Then, bioinformatics prediction, dual-luciferase reporter, qRT-PCR, and Western blot was conducted to confirm the down-stream target of miR-802.ResultsMiR-802 was frequently down-regulated in CRC tissues and cells. Further analyses showed that the low expression of miR-802 in CRC tissues was significantly correlated with tumor progression and poor patients’ prognosis. Overexpression of miR-802 profoundly inhibited proliferation, migration and invasion but promoted apoptosis of CRC cells, by contrast, miR-802 silencing exhibited opposite effects in vitro. Further animal experiment demonstrated that miR-802 could suppress tumor growth via inhibiting the proliferation and promoting the apoptosis of CRC cells in vivo. Mechanistically, miR-802 functioned as a tumor suppressor through inhibiting the expression of Ubinuclein-2 (UBN2) on post-transcriptional level. Moreover, upregulation of UBN2 expression could reverse the biological effects of CRC cells induced by miR-802 overexpression.ConclusionOur study demonstrates that miR-802 inhibits the proliferation, migration and invasion while promotes the apoptosis of CRC cells via directly suppressing UBN2 expression. These findings provide a promising biomarker and potential treatment target for CRC.

Exosomal MALAT1 sponges miR-26a/26b to promote the invasion and metastasis of colorectal cancer via FUT4 enhanced fucosylation and PI3K/Akt pathway

BackgroundExosomes are vesicles of endocytic origin released by various cell types and emerging as important mediators in tumor cells. Human metastases-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA known to promote cell proliferation, metastasis, and invasion in colorectal cancer (CRC).MethodsThe expression of MALAT1 was analyzed in CRC using qRT-PCR. FUT4 and fucosylation levels were detected in CRC clinical samples and CRC cell lines by immunofluorescent staining, western blot and lectin blot analysis. CRC derived exosomes were isolated and used to examine their tumor-promoting effects in vitro and in vivo.ResultsThe invasive and metastatic abilities of primary CRC cells were enhanced after exposure to exosomes derived from highly metastatic CRC cells, which increased the fucosyltransferase 4 (FUT4) levels and fucosylation not by directly transmitting FUT4 mRNA. Exosomal MALAT1 increased FUT4 expresssion via sponging miR-26a/26b. Furthermore, MALAT1/miR-26a/26b/FUT4 axis played an important role in exosome-mediated CRC progression. Exosomal MALAT1 also mediated FUT4-associated fucosylation and activated the PI3K/AKT/mTOR pathway.ConclusionsThese data indicated that exosomal MALAT1 promoted the malignant behavior of CRC cells by sponging miR-26a/26b via regulating FUT4 and activating PI3K/Akt/mTOR pathway.

MiR-338-3p regulates the proliferation, apoptosis and migration of SW480 cells by targeting MACC1.

The mortality and incidence rates of colorectal cancer (CRC) vary widely worldwide. miR-338-3p inhibits tumor cell proliferation in several types of cancer, however, the role of miR-338-3p on CRC remains unknown. The aim of the current study was to investigate the cellular function of miRNA-338-3p (miR-338-3p) in CRC, the malignant behavior of CRC cells and the interaction between miR-338-3p and metastasis-associated in colon cancer-1 (MACC1). miR-338-3p expression was significantly decreased in CRC tissue compared with adjacent normal tissue. In the CRC cell line SW480, miR-338-3p overexpression suppressed cell proliferation and migration and induced G1/S cell cycle arrest and apoptosis. By contrast, miR-338-3p knockdown significantly enhanced cell proliferation and migration, and suppressed G1/S cell cycle arrest and apoptosis. Furthermore, the dual-luciferase reporter assay confirmed MACC1 as a direct target of miR-338-3p. In addition, miR-338-3p overexpression reduced the level of MACC1 protein expression and MACC1 expression was significantly upregulated in CRC tissue samples. MACC1 siRNA significantly reduced CRC cell proliferation and migration, whilst cell apoptosis was significantly increased. In conclusion, miR-338-3p expression was decreased in CRC. miR-338-3p regulated the proliferation, apoptosis and migration of CRC cells by targeting MACC1.

Silencing of Girdin suppresses the malignant behavior of colorectal carcinoma cells.

The aim of the present study was to investigate the effect of the actin‑binding protein Girdin on the proliferation, invasion and migration of colorectal cancer (CRC) cells. Cultured CRC cells (LoVo cell line) were transfected by Girdin‑specific and control shRNA constructs and analyzed for proliferation, invasion and migration by the MTT, Transwell and wound‑healing assays, respectively. The activation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway and expression of proinflammatory cytokines was examined by western blotting and ELISA assay, respectively. The effect of Girdin silencing on CRC growth was also evaluated in a xenograft model using nude mice, which were subcutaneously injected with Girdin‑deficient and negative control LoVo cells and analyzed for tumor volume and weight. Transfection of LoVo cells with Girdin‑specific shRNA inhibited Girdin mRNA expression to 27.5% and protein expression to 36.7% when compared with expression levels in the control cells (P<0.001) and significantly demonstrated suppression of LoVo cell proliferation (P<0.05), invasion (P<0.01) and migration (P<0.01). Furthermore, Girdin silencing downregulated the phosphorylation of the signaling proteins JAK (by 42%, P<0.001) and STAT3 (by 34%, P<0.01) and the content of IFN (by 28%, P<0.001) and IL‑6 (by 44%, P<0.001) compared to the control. Notably, inhibition of Girdin expression effectively suppressed tumorigenicity of LoVo cells invivo as evidenced by the reduced volume (P<0.05) and weight (P<0.05) of the tumors derived from Girdin shRNA‑transfected LoVo cells compared to those from the control cells. In conclusion, the silencing of Girdin expression inhibited the malignant behavior of CRC cells via the downregulation of the JAK/STAT signaling pathway, indicating Girdin as a potential therapeutic target in CRC. In the present study, we revealed, for the first time, that the malignant behavior of CRC cells depended on the expression of an actin‑binding protein, Girdin. Silencing of Girdin expression by specific shRNA suppressed the proliferation, invasion, and migration of CRC cells through the decrease in proinflammatory cytokines IFN and IL‑6 and the downregulation of the JAK/STAT signaling pathway. Our findings indicated that Girdin expression may be a potential novel therapeutic target in CRC.

NOTCH4 regulates colorectal cancer proliferation, invasiveness, and determines clinical outcome of patients.

Notch signal has complex roles in human malignancies, which might be attributed to the diversity of Notch receptors. Here, we set out to identify the association of NOTCH4 with colorectal cancer (CRC). In the hospital-based study cohort, we investigated NOTCH4 mRNA levels in primary CRC, as well as its association with clinicopathologic characteristics. Besides, NOTCH4 cDNA and siRNA was transfected into colorectal cancer cell line to elucidate its impact on tumor cell proliferation and migration. Results revealed a statistically significant lower expression of NOTCH4 mRNA in tumor specimens compared with that in control. NOTCH4 level in CRC was found to be related to tumor differentiation, invasion, and node metastasis. Moreover, it was demonstrated that NOTCH4 mRNA level could be an independent prognostic factor for both disease-free and overall survival of CRC patients. Overexpression of NOTCH4 in CRC cell lines suppressed tumor cell proliferation, migration, and invasion, while induced apoptosis. In the opposite, the malignant behavior of CRC cells was enhanced by NOTCH4 knockdown. These results demonstrated for the first time that NOTCH4 expression was decreased in CRC, which could determine tumor proliferation, relapse, and prognosis.

Silencing of plasminogen activator inhibitor-1 suppresses colorectal cancer progression and liver metastasis

Plasminogen activator inhibitor-1 (PAI-1) is reported to be expressed in many cancer cell types and regarded as one of the most informative biochemical markers for poor prognosis. However, no previous study has evaluated whether PAI-1 could serve as a target in antitumor and antimetastasis therapies of colorectal cancer (CRC). The plasma level of PAI-1 in CRC patients was detected and its correlation with the clinicopathologic features was evaluated. PAI-1 protein expression was assessed by Western blot assay and immunohistochemistry. The biologic consequences of PAI-1 silencing in colon cancer cell lines and CRC bearing nude mice were also investigated. Plasma PAI-1 level was higher in CRC patients with liver metastasis and correlated with liver metastasis, tumor size, differentiation, serosa infiltration, Duke's stage, and lymphatic metastasis. PAI-1 protein expression in the CRC tissue of patients with liver metastasis was significantly greater than that in those without liver metastasis. In addition, the abilities of proliferation, invasion, and migration of CRC cells transfected with lentivirus expressing PAI-1 small interfering RNA were reduced significantly. Nude mice inoculated with PAI-1 knockdown cells also had fewer metastatic nodules in the liver and smaller tumor volumes. Plasma PAI-1 level was increased in CRC patients with liver metastasis, and PAI-1 silencing may significantly compromise the malignant behaviors of CRC cells in vitro and in vivo. These findings may provide evidence for PAI-1 targeted therapy of CRC.