CircPOFUT1 fosters colorectal cancer metastasis and chemoresistance via decoying miR-653-5p/E2F7/WDR66 axis and stabilizing BMI1.

CircRNAs are implicated in colorectal cancer (CRC) development and progression. Protein O-fucosyltransferase 1 (POFUT1) plays an oncogenic role via activating Notch1 signaling in CRC. However, the roles of circPOFUT1, which is originated from POFUT1, have not been investigated. Our study showed circPOFUT1 was highly expressed in CRC tissues and cells. CircPOFUT1 enhanced the proliferation, migration and invasion of CRC cells, and promoted tumor growth and liver metastasis in vivo. It also reinforced stemness and chemoresistance of CRC cells. Mechanistically, circPOFUT1 regulated the function of E2F7 via sponging miR-653-5p, thereby transcriptionally inducing WDR66 expression and further promoting metastasis in CRC. On the other hand, circPOFUT1 promoted stemness and chemoresistance of CRC cells via stabilizing BMI1 in an IGF2BP1-dependent manner. In conclusion, circPOFUT1 fosters CRC metastasis and chemoresistance via decoying miR-653-5p/E2F7/WDR66 axis and stabilizing BMI1.

Exosomal circCOL1A1 promotes angiogenesis via recruiting EIF4A3 protein and activating Smad2/3 pathway in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is the third frequently diagnosed cancer with high incidence and mortality rate worldwide. Our previous report has demonstrated that circCOL1A1 (hsa_circ_0044556) functions as an oncogene in CRC, and Gene Ontology (GO) analysis has also revealed the strong association between circCOL1A1 and angiogenesis. However, the mechanism of circCOL1A1 or exosomal circCOL1A1 in CRC angiogenesis remains elusive. METHODS: Purified exosomes from CRC cells were characterized by nanoparticle tracking analyzing, electron microscopy and western blot. qRT-PCR, immunohistochemistry or western blot were employed to test the expression of circCOL1A1, EIF4A3, Smad pathway and angiogenic markers. Cell proliferation of HUVECs was monitored by CCK-8 assay. The migratory and angiogenic capabilities of HUVECs were detected by wound healing and tube formation assay, respectively. Bioinformatics analysis, RNA immunoprecipitation (RIP), RNA pull-down and FISH assays were used to detect the interactions among circCOL1A1, EIF4A3 and Smad2/3 mRNA. The in vitro findings were verified in xenograft model. RESULTS: CRC cell-derived exosomal circCOL1A1 promoted angiogenesis of HUVECs via recruiting EIF4A3. EIF4A3 was elevated in CRC tissues, and it stimulated angiogenesis of HUVECs through directly binding and stabilizing Smad2/3 mRNA. Moreover, exosomal circCOL1A1 promoted angiogenesis via inducing Smad2/3 signaling pathway in vitro, and it also accelerated tumor growth and angiogenesis in vivo. CONCLUSION: CRC cell-derived exosomal circCOL1A1 promoted angiogenesis via recruiting EIF4A3 and activating Smad2/3 signaling.

Intergenic CircRNA Circ_0007379 Inhibits Colorectal Cancer Progression by Modulating miR-320a Biogenesis in a KSRP-Dependent Manner.

Circular RNAs (circRNAs) are covalently closed RNA structures that play multiple roles in tumorigenesis and progression. Compared with exon‒intron circRNAs, the biological functions and implications of intergenic circRNAs in human cancer are still poorly understood. Here, we performed circRNA microarray analysis and identified an intergenic circRNA, circ_0007379, that was significantly downregulated in patients with colorectal cancer (CRC). The biogenesis of circ_0007379 was mediated by reverse complementary matches (RCMs) and was negatively regulated by the RNA helicase DHX9. Functionally, circ_0007379 suppressed CRC cell growth and metastasis in cell culture as well as in patient-derived organoid and xenograft models. Mechanistically, circ_0007379 acted as a scaffold to facilitate the processing of both pri-miR-320a and pre-miR-320a in a KSRP-dependent manner, leading to miR-320a maturation and subsequent repression of transcription factor RUNX1 expression. Thus, our findings establish a previously unrecognized function of circRNA in inhibiting CRC progression.

METTL3-Modulated circUHRF2 Promotes Colorectal Cancer Stemness and Metastasis through Increasing DDX27 mRNA Stability by Recruiting IGF2BP1.

Increasing evidence has implicated that circular RNAs (circRNAs) exert important roles in colorectal cancer (CRC) occurrence and progression. However, the role of a novel circRNA, circUHRF2, remains unknown in CRC. Our work aimed at identifying the functional roles of circUHRF2 in CRC and illustrating the potential mechanisms. As assessed by quantitative real-time PCR (qRT-PCR), circUHRF2 and methyltransferase-like 3 (METTL3) were highly expressed in CRC specimens and cells. Sanger sequencing and RNase R assays were performed to verify the ring structure of circUHRF2. Notably, aberrantly increased expression of circUHRF2 was positively correlated with poor prognosis of CRC patients. Functional experiments indicated that CRC stemness, migration, and epithelial-mesenchymal transition (EMT) were suppressed by the knockdown of circUHRF2 or METTL3. Mechanistically, METTL3 enhanced circUHRF2 expression through N6-methyladenine (m6A) modification. Rescue experiments showed that overexpression of circUHRF2 reversed the repressive effect of METTL3 silencing on CRC progression. Moreover, circUHRF2 inhibited the loss of DEAD-box helicase 27 (DDX27) protein via promoting the interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and DDX27 mRNA. DDX27 knockdown repressed CRC malignant properties, which was counteracted by circUHRF2 overexpression. The in vivo assays in nude mice demonstrated that circUHRF2 or METTL3 silencing exerted a suppressive effect on CRC growth and liver metastasis via repressing DDX27 protein expression. Taken together, METTL3-mediated m6A modification upregulated circUHRF2 and subsequently inhibited loss of DDX27 protein via recruitment of IGF2BP1, which conferred CRC stemness and metastasis. These findings shed light on CRC pathogenesis and suggest circUHRF2 as a novel target for CRC treatment.

Circ_RNF13 Regulates the Stemness and Chemosensitivity of Colorectal Cancer by Transcriptional Regulation of DDX27 Mediated by TRIM24 Stabilization.

BACKGROUND: Colorectal cancer (CRC) is one of the most commonly diagnosed cancers with high incidence and poor prognosis worldwide. Circ_RNF13 is upregulated in CRC; however, the biological roles and downstream signaling of circ_RNF13 remain undefined. METHODS: The characterization of circ_RNF13 was determined by Sanger sequencing, qRT-PCR, subcellular fractionation assay, and RNA FISH. Western blot analysis and qRT-PCR were employed to detect the expression of the key molecules and stemness markers in CRC tumor samples and cells. The stem-like activities of CRC cells were assessed by sphere formation assay, flow cytometry, and immunofluorescence (IF). Cell viability was monitored by CCK-8 assay. The chemosensitivity of CRC cells was assessed by colony formation and cell apoptosis assays. Bioinformatics analysis, RIP assay, RNA pull-down assay, and FISH/IF staining were used to detect the association between circ_RNF13 and TRIM24. The transcriptional regulation of DDX27 was investigated by ChIP assay, and the post-translational regulation of TRIM24 was detected by Co-IP. The in vitro findings were verified in a xenograft model. RESULTS: circ_RNF13 and DDX27 were elevated in CRC tumor samples and cells. Knockdown of circ_RNF13 or DDX27 inhibited stemness and increased chemosensitivity in CRC cells. Mechanistically, circ_RNF13 regulated DDX27 expression via TRIM24-mediated transcriptional regulation, and circ_RNF13 stabilized TRIM24 via suppressing FBXW7-mediated TRIM24 degradation. In vivo studies revealed that the knockdown of circ_RNF13 impaired stemness and enhanced the chemosensitivity of CRC in the xenograft model. CONCLUSION: circ_RNF13 regulated the stemness and chemosensitivity of CRC by transcriptional regulation of DDX27 mediated by TRIM24 stabilization.

LINC01210 promotes malignant phenotypes of colorectal cancer through epigenetically upregulating SRSF3.

Long non-coding RNAs (lncRNAs) have been linked to tumorigenesis. However, the role of LINC01210 in colorectal cancer (CRC) remains unclear. Relative levels of LINC01210 in CRC tissues and adjacent tissues were determined. Proliferative, migratory, and invasive abilities were examined in HCT116 cells and LoVo cells after silencing or overexpressing LINC01210. The interaction between LINC01210 and SRSF3 was explored by ChIP-PCR. Upregulated LINC01210 was associated with metastasis and advanced stage of CRC. Silencing LINC01210 attenuated proliferative, migratory, and invasive abilities in LoVo cells, while overexpressing LINC01210 promoted proliferative, migratory, and invasive abilities in HCT116 cells. Mechanism study revealed that LINC01210 increased the expression of SRSF3 by recruiting mixed lineage leukaemia protein-1, which upregulated the trimethylation of H3K4 me3 on SRSF3 promoter. Silencing SRSF3 reversed the effects of LINC01210 on CRC cells. In conclusions, LINC01210 accelerated proliferation and invasion in CRC cells through epigenetically upregulating SRSF3, and may be a potential therapeutic target for CRC treatment.

The N6-methyladenosine modification of circALG1 promotes the metastasis of colorectal cancer mediated by the miR-342-5p/PGF signalling pathway.

BACKGROUND: Previous studies have shown that the N6-methyladenosine (m6A) modification enhances the binding ability of mRNAs/long noncoding RNAs (lncRNAs) to microRNAs (miRNAs), but the impact of this modification on the competitive endogenous RNA (ceRNA) function of circular RNAs (circRNAs) is unclear. METHODS: We used a human circRNA microarray to detect the expression profiles of circRNAs in 3 pairs of cancer and paracancerous tissues from patients with colorectal cancer (CRC) and 3 pairs of peripheral blood specimens from patients with CRC and healthy individuals. The circRNAs highly expressed in both peripheral blood and tumour tissues of patients with CRC, including circALG1, were screened. A quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis of an expanded sample size was performed to detect the expression level of circALG1 in peripheral blood and tumour tissues of patients with CRC and determine its correlation with clinicopathological features, and circRNA loop-forming validation and stability assays were then conducted. Transwell assays and a nude mouse cancer metastasis model were used to study the function of circALG1 in CRC and the role of altered m6A modification levels on the regulation of circALG1 function. qRT-PCR, western blot (WB), Transwell, RNA-binding protein immunoprecipitation (RIP), RNA antisense purification (RAP), and dual-luciferase reporter gene assays were performed to analyse the ceRNA mechanism of circALG1 and the effect of the m6A modification of circALG1 on the ceRNA function of this circRNA. RESULTS: CircALG1 was highly expressed in both the peripheral blood and tumour tissues of patients with CRC and was closely associated with CRC metastasis. CircALG1 overexpression promoted the migration and invasion of CRC cells, and circALG1 silencing and reduction of the circALG1 m6A modification level inhibited CRC cell migration and invasion. In vivo experiments further confirmed the prometastatic role of circALG1 in CRC. Further mechanistic studies showed that circALG1 upregulated the expression of placental growth factor (PGF) by binding to miR-342-5p and that m6A modification enhanced the binding of circALG1 to miR-342-5p and promoted its ceRNA function. CONCLUSION: M6A modification enhances the binding ability of circALG1 to miR-342-5p to promote the ceRNA function of circALG1, and circALG1 could be a potential therapeutic target in and a prognostic marker for CRC.

Identification of circular RNA hsa_circ_0044556 and its effect on the progression of colorectal cancer.

BACKGROUND: Circular RNAs (circRNAs) are a novel class of noncoding RNAs. Increasing evidence indicates that circRNAs play an important role in the occurrence and development of tumors. However, the role of circRNA hsa_circ_0044556 in the progression of colorectal cancer (CRC) remains unclear. METHODS: First, we searched for differentially expressed circRNAs using a circRNA microarray in paired CRC and adjacent normal tissues. The circRNA hsa_circ_0044556 was screened out from the existing CRC circRNA microarray in the Gene Expression Omnibus database and our microarray. The clinical significance of hsa_circ_0044556 expression level in CRC patients was then investigated. Finally, the functions of the targets of this circRNA were determined in CRC cell lines. RESULTS: Hsa_circ_0044556 was highly expressed in CRC patients and was positively correlated with tumor stage and lymph node metastasis. In CRC cell lines, the proliferation, migration, and invasion of cancer cells were inhibited by knocking down hsa_circ_0044556 expression. CONCLUSION: Hsa_circ_0044556 promoted the progression of CRC. It is possible that hsa_circ_0044556 will become a novel biomarker or therapeutic target for CRC.

Knockdown of Long Noncoding RNA GHET1 Inhibits Cell Proliferation and Invasion of Colorectal Cancer.

Emerging evidence has identified the vital role of long noncoding RNAs (lncRNAs) in the development of colorectal cancer. In this study, we aimed to investigate the role of lncRNA gastric carcinoma highly expressed transcript 1 (GHET1) in colorectal cancer. We analyzed the expression of GHET1 in colorectal cancer (CRC) tissues by using ISH. We found that GHET1 expression was significantly increased in the CRC samples compared with adjacent tissues. Furthermore, the cancer tissues had higher GHET1 mRNA levels than their matched adjacent tissues. GHET1 expression was also significantly increased in the CRC cell lines compared with human normal colon epithelial cells. Downregulation of GHET1 mediated by shRNA suppressed the proliferation, cell cycle arrest, migration, and invasion of colorectal cancer cells in vitro. In addition, inhibition of GHET1 reversed the epithelial-mesenchymal transition in colorectal cancer cell lines. Taken together, our results suggest the potential use of GHET1 as a therapeutic target of colorectal cancer.

Combinational treatment with microRNA­133b and cetuximab has increased inhibitory effects on the growth and invasion of colorectal cancer cells by regulating EGFR.

Colorectal cancer (CRC) is the third most common cancer with a very poor prognosis predominantly due to its high rate of tumor invasion and migration, and its resistance to anti­epidermal growth factor receptor (EGFR) therapy. Although CRC has been widely studied, the underlying molecular mechanism remains to be elucidated. MicroRNA (miR)­133b has been demonstrated to act as a tumor suppressor in several human cancer types by regulating EGFR. However, the detailed involvement of miR­133b and EGFR in CRC cells remain to be elucidated. The present study used reverse transcription quantitative polymerase chain reaction and characterized the downregulation of the expression levels of miR­133b in CRC tissues and cell lines. Cell functional assays demonstrated that restored expression of miR­133b inhibited the growth and invasion of CRC cells. In addition, a luciferase reporter assay revealed that miR­133b directly targeted EGFR and repressed its expression levels in CRC cells. Additionally, combination treatment with miR­133b mimics and the monoclonal anti­EGFR antibody, cetuximab, which is approved and frequently used for treating patients with CRC, exhibited improved inhibitory effects on the growth and invasion of CRC cells compared with treatment with either alone. Taken together, the present study characterized the role of the miR­133b/EGFR interaction in CRC cells and this suggested the combinational therapy with cetuximab and miR­133b was positive and may be a potential novel treatment for patients with CRC in the future.

Factors predicting surgical resection in patients with intrahepatic cholangiocarcinoma and cirrhosis.

Here, we investigate the potential factors that affect the outcome of patients with intrahepatic cholangiocarcinomas (ICC) and cirrhosis. We retrospectively reviewed the clinical data and pathological features of 58 patients with ICC and cirrhosis who underwent liver resection between July 2000 and March 2008, and analyzed the prognostic risk factors by means of univariate and multivariate analyses. The overall morbidity and mortality were 40% and 3.3%, respectively. The overall median survival was 24 months, and the 1-, 3-, and 5-year actuarial survival rates were 53%, 18%, and 10%, respectively. Univariate analysis showed that Child-Pugh classification, hypoalbuminemia, vascular invasion, lymphnodes metastasis, tumor-nodes-metastasis (TNM) staging system, positive surgical margins, and high perioperative blood transfusion volumes were all significantly associated with poor survival. Multivariate analysis confirmed that hypoalbuminemia, vascular invasion, positive surgical margins, and high perioperative blood transfusion volume were survival related, with hazard ratios (HR) of 2.58, 3.12, 3.57, and 1.98, respectively. Surgical resection is an effective treatment for patients affected by ICC and cirrhosis. Predictive factors, including hypoalbuminemia, vascular invasion, positive surgical margins, and high perioperative blood transfusion volumes are all related to poor survival.

Major hepatectomy is a safe modality for the treatment of intrahepatic cholangiocarcinoma in selected patients complicated with cirrhosis.

OBJECTIVE: The objective of this paper is to evaluate the perioperative outcomes of major hepatectomy for intrahepatic cholangiocarcinoma (ICC) in patients with cirrhosis. METHODS: We retrospectively evaluated the preoperative, intraoperative, and postoperative findings in 42 consecutive patients with cirrhosis and in 102 patients with normal livers who underwent major hepatectomy for ICC. RESULTS: Preoperative liver function was worse in patients with cirrhosis compared to patients without cirrhosis. Cirrhotic patients had significantly higher intraoperative blood loss, longer operation time, and longer hospital stay than non-cirrhotic patients. However, the two groups had similar overall morbidity and hospital mortality rates and similar rates of liver failure or other complications. Their R0 resection rates, resection margin widths and disease-free survival rates were also similar. CONCLUSIONS: Major hepatectomy for ICC can be performed in selected cirrhotic patients with acceptable morbidity and mortality rates, as compared to patients without cirrhosis.

Expression of deleted in liver cancer 2 in colorectal cancer and its correlation with clinicopathological parameters.

Deleted in liver cancer 2 (DLC2) has been identified as a tumor suppressor gene. DLC2 is closely related to deleted in liver cancer 1 (DLC1) and is located at chromosome 13q12.3. The expression of DLC2 mRNA has been found in a wide range of cancers, including colorectal cancer (CRC). However, there are no available data on the expression status of DLC2 in Chinese patients with CRC and its correlation with clinicopathological parameters. The aim of this study was to investigate the expression levels of DLC2 mRNA and protein in Chinese patients with CRC and the correlation between DLC2 expression and clinicopathological parameters. To this end, real-time PCR, western blotting and immunohistochemistry were employed to detect DLC2 mRNA and protein expression in CRC and pericarcinomatous intestinal tissue (PCIT) specimens, which were obtained from 102 Chinese CRC patients who underwent surgical resection between October 2010 and February 2012. We also analyzed the correlations between DLC2 expression and the clinicopathological parameters of CRC patients. Our results showed that CRC tissues had significantly lower levels of DLC2 mRNA compared with PCITs (P<0.05); however, the protein expression levels were not significantly different between CRCs and PCITs. The expression levels of DLC2 mRNA and protein were significantly correlated with lymph node metastasis and tumor TNM stage. Additionally, DLC2 mRNA expression levels were also correlated with tumor histopathological degree (P<0.05). Collectively, our results suggest that the downregulated expression of DLC2 participates in CRC carcinogenesis, invasion and lymph node metastasis. Furthermore, our results imply that DLC2 is be a potential prognostic marker for CRC patients.

Exenatide-induced chronic damage of pancreatic tissue in rats.

OBJECTIVE: The study aimed to explore exenatide-induced damage of pancreatic tissue in rats. METHODS: At first stage, 30 male rats were randomly divided into exenatide and control groups. At second stage, 10 male and 10 female rats were treated according to sex, exenatide dose and time, and with or without inhibitor. Exenatide was injected subcutaneously twice a day, and body weights were measured once a week. At approximately 10 weeks, blood and pancreatic tissue samples were harvested. Amylase, lipase, interleukin 1, interleukin 6, and tumor necrosis factor α in serums were determined. Pancreatic tissues were divided for dry-wet ratio, myeloperoxidase, hematoxylin-eosin staining, and electric microscope imaging. RESULTS: Compared with the control group, myeloperoxidase in pancreatic tissue of rats administered with exenatide exhibited a significantly high level; dry-wet ratio of pancreatic tissue in rats administered with exenatide exhibited a significantly low level. Chronic pancreatic damage was observed in 30% of rats from exenatide group for both sexes and showed pycnosis of acinar cells, increased cytoplasmic vacuoles, widened cellular gap, and inflammatory cell infiltration in pancreatic tissue. No pancreatic damage was observed in the control and the inhibitor groups. Histopathological evaluation scores in exenatide group were significantly higher than those of the control group. CONCLUSION: Long-term administration of exenatide in rats can result in chronic pancreatic damage.

Clinicopathological characteristics of intrahepatic cholangiocarcinoma in patients with cirrhosis.

BACKGROUND/AIMS: The purpose of this study was to explore the clinicopathological characteristics of intrahepatic cholangiocarcinoma (ICC) in patients with cirrhosis. METHODOLOGY: A total of 155 patients with ICC were divided into those with cirrhosis (n=52) and those without cirrhosis (n=103). We compared the clinicopathological features of patients in both groups. RESULTS: The prevalence of HBsAg seropositivity and hepatolithiasis in ICC patients with cirrhosis was higher than that in patients without cirrhosis. Compared with noncirrhotic patients, cirrhotic patients had a higher incidence of reduced albumin (46.1% vs. 25.2%, p<0.008) and elevated total bilirubin (TBIL) levels (44.2% vs. 24.3%, p=0.011). The resectability rate in cirrhotic patients was lower than that in noncirrhotic patients (63.7% vs. 80.6%, p=0.033). CONCLUSIONS: Among ICC patients, we found marked differences in clinicopathological characteristics and therapeutic approaches between cirrhotic and noncirrhotic patients. ICC patients with cirrhosis may have poorer prognosis than those without cirrhosis.

Prognostic value of cirrhosis for intrahepatic cholangiocarcinoma after surgical treatment.

BACKGROUND: The surgical outcome and prognostic factors of intrahepatic cholangiocarcinoma are not fully understood. This study aimed to establish the clinical significance of cirrhosis for prognosis in patients with intrahepatic cholangiocarcinoma after surgery. METHODS: One hundred fifteen patients with intrahepatic cholangiocarcinoma who underwent surgical resection between December 2001 and January 2008 were retrospectively analyzed. The prognostic significance of clinicopathologic factors including cirrhosis was assessed by univariate and multivariate analyses. RESULTS: Thirty-two of the 115 patients (28%) had liver cirrhosis. Complete tumor removal (R0 resection) was performed in 42 patients (75%). Overall median survival time was 21 months, with 1-, 3-, and 5-year actuarial survival rates of 68%, 27%, and 17%, respectively. There was a significant difference in survival between patients with cirrhosis and those without cirrhosis (P = 0.027). Univariate analysis showed that cirrhosis, vascular invasion, hepatic duct invasion, lymph node metastasis, positive surgical margin (R1), and TNM stage were significantly associated with poor survival. Multivariate analysis showed that cirrhosis, positive surgical margin, and lymph node metastases were related to survival, with hazard ratios of 2.49, 3.53, and 4.16, respectively. CONCLUSIONS: Cirrhosis is an independent factor for poor prognosis in intrahepatic cholangiocarcinoma after surgery.

[Expression of X-linked inhibitor of apoptosis protein in colorectal cancer tissues].

OBJECTIVE: To investigate the expression of X-linked inhibitor of apoptosis protein (XIAP) in colorectal cancer tissues and investigate its correlation with the clinicopathological factors of the malignancy. METHODS: Immunohistochemistry and RT-PCR was employed to detect the expression of XIAP in 87 colorectal cancer tissues. RESULTS: XIAP mRNA expression was detected in 64.4% (56/87) of the colorectal cancer tissues, 49.4% (43/87) of the adjacent tissues, and in 11.4% (10/87) of the normal tissues, respectively. The cancer tissues showed significant greater positivity rate and higher expression level of XIAP mRNA than the adjacent and normal tissues. Immunohistochemistry also identified a significantly greater positivity rate for XIAP [70.1% (61/87)] in the colorectal cancer tissues. The pathological grade of the tumors was associated with the expression level of XIAP, whereas this association was not established between XIAP expression and the clinical stages, tumor position or lymph node metastasis. CONCLUSION: XIAP may play an important role in the development of colorectal cancer, which might serve as a potentially useful tumor marker.

Preparation, characterization and transfection efficiency of cationic PEGylated PLA nanoparticles as gene delivery systems.

The cationic polylactic acid (PLA) nanoparticle has emerged as a promising non-viral vector for gene delivery because of its biocompatibility and biodegradability. However, they are not capable of prolonging gene transfer and high transfection efficiency. In order to achieve prolonged delivery of cationic PLA/DNA complexes and higher transfection efficiency, in this study, we used copolymer methoxypolyethyleneglycol-PLA (MePEG-PLA), PLA and chitosan (CS) to prepare MePEG-PLA-CS NPs and PLA-CS NPs by a diafiltration method and prepared NPs/DNA complexes through the complex coacervation of nanoparticles with the pDNA. The object of our work is to evaluate the characterization and transfection efficiency of MePEG-PLA-CS versus PLA-CS NPs. The MePEG-PLA-CS NPs have a zeta potential of 15.7 mV at pH 7.4 and size under 100 nm, while the zeta potential of PLA-CS NPs was only 4.5 mV at pH 7.4. Electrophoretic analysis suggested that both MePEG-PLA-CS NPs and PLA-CS NPs with positive charges could protect the DNA from nuclease degradation and cell viability assay showed MePEG-PLA-CS NPs exhibit a low cytotoxicity to normal human liver cells. The potential of PLA-CS NPs and MePEG-PLA-CS NPs as a non-viral gene delivery vector to transfer exogenous gene in vitro and in vivo were examined. The pDNA being carried by MePEG-PLA-CS NPs, PLA-CS NPs and lipofectamine could enter and express in COS7 cells. However, the transfection efficiency of MePEG-PLA-CS/DNA complexes was better than PLA-CS/DNA and lipofectamine/DNA complexes by inversion fluorescence microscope and flow cytometry. It was distinctively to find that the transfection activity of PEGylation of complexes was improved. The nanoparticles were also tested for their ability to transport across the gastrointestinal mucosa in vivo in mice. In vivo experiments showed obviously that MePEG-PLA-CS/DNA complexes mediated higher gene expression in stomach and intestine of BALB/C mice compared to PLA-CS/DNA and lipofectamine/DNA complexes. These results suggested that MePEG-PLA-CS NPs have favorable properties for non-viral gene delivery.

[Sentinel lymph node mapping in colorectal cancer: study of 45 cases].

OBJECTIVE: To discuss the sentinel lymph node (SLN) mapping technique in colorectal cancer and its feasibility and utility. METHODS: The dye lymphazurin was injected subserosally around the tumor during operation in 43 colorectal cancer, 20 males and 25 females, aged 49.5 (27 - 72) so as to find the SLNs. Fast-frozen pathology and routine pathology were performed too. RESULTS: SLN was successfully identified in 42 of the 45 patients, with a successful biopsy rate of 93.3%. In these 45 patients, there were 250 lymph nodes examined, of which 52 nodes were identified as SLNs. The sensitivity was 90.4% (20/22), the specificity was 95.2% [(20 + 20)/42], and the false negative rate was 15% (3/20). CONCLUSION: SLN mapping in colorectal cancer plays an important role in diagnosing metastasis of lymph nodes, and can be used to direct the clinical surgery.