Enyu Liu

Transvaginal laparoscopically assisted endoscopic cholecystectomy: preliminary clinical results for a series of 43 cases in China

BackgroundTransvaginal cholecystectomy has been performed successfully at several research institutions worldwide using natural orifice transluminal endoscopic surgery (NOTES) techniques. However, it is a growing new surgical concept in China. Several technical challenges hinder the safe clinical application of NOTES. This study investigated transvaginal endoscopic cholecystectomy performed with the assistance of a single umbilical trocar and achieved helpful initial clinical experience.MethodsFrom May 2009 to April 2010, a total of 43 transvaginal human cholecystectomies were performed. A single umbilical trocar was used for safe access and laparoscopic assistance during the operation. After the gallbladder had been removed through the vagina, the colpotomy was closed with absorbable stitches under direct vision. In addition, Student’s t-test was performed for two samples to estimate the superiority of NOTES over a conventional laparoscopic cholecystectomy (LC) operation.ResultsThe procedure was successfully completed for all the patients. No intra- or post-operative complications occurred. The patients recovered promptly after surgery, and all were satisfied with ideal cosmetic outcomes. The postoperative pain, hospital stay, and cost of hospitalization with NOTES were much less than with conventional LC operations.ConclusionsAlthough endoscopic instruments specifically designed for NOTES are not available, the addition of an umbilical trocar is an optimal way to allow safe performance of NOTES procedures in an easily reproducible manner. The authors’ initial experience demonstrates that this hybrid technique is potentially feasible and effective for reducing postoperative pain and recovery times while improving the cosmetic results of transvaginal cholecystectomy.

SDF-1/CXCR4 axis promotes directional migration of colorectal cancer cells through upregulation of integrin αvβ6

Colorectal cancer (CRC) displays a predilection for metastasis to liver. Although stromal cell-derived factor-1 (SDF-1)/CXCR4 plays an important role in the liver metastasis, the molecular mechanism still remains obscure. We previously reported that integrin αvβ6 was implicated in the progression of CRC. However, no data are currently available on the cross talk between CXCR4 and αvβ6. In the present study, we first demonstrated the cross talk between CXCR4 and αvβ6 and their role in liver metastasis of CRC. We analyzed 159 human CRC samples and found that expression of CXCR4 and αvβ6 was significantly associated with liver metastasis, and interestingly expression of αvβ6 significantly correlated with expression of CXCR4. Both CXCR4 and αvβ6 were highly expressed in metastatic CRC cell lines HT-29 and WiDr, whereas both of them were exiguous in non-metastatic cell line Caco-2. Furthermore, inhibition of αvβ6 significantly decreased SDF-1α-induced cell migration in vitro. SDF-1/CXCR4 could upregulate αvβ6 expression through phosphorylation of ERK and activation of Ets-1 transcription factor. In conclusion, we demonstrate that SDF-1/CXCR4 induces directional migration and liver metastasis of CRC cells by upregulating αvβ6 through ERK/Ets-1 pathway. These data support combined inhibition of CXCR4 and αvβ6 to prevent development of liver metastasis of CRC.

The β6-integrin-ERK/MAP kinase pathway contributes to chemo resistance in colon cancer

5-Fluorouracil (5-FU) is the most widely used chemo drug for the treatment of colon cancer. However, a sub-population of colon cancer patients do not respond to 5-FU and this treatment does not provide survival benefit due to chemo resistance. The mechanisms involved in 5-FU resistance are not fully understood and multiple factors have been involved in the sensitivity of cancer cells to 5-FU. We previously reported that β6-integrin plays an important role in invasion, metastasis and degradation of extracellular matrix of colon cancer. In this study, we investigated whether β6-integrin is associated with chemo resistance in colon cancer. We found that over-expression of β6-integrin protected SW480 and HT-29 colon cancer cells from 5-FU-induced growth inhibition and apoptosis, which were accompanied by changes in cytochrome C released from the mitochondria and activity of caspase-3 and caspase-9. Moreover, β6-integrin resulted in up-regulation of Bcl-2 and down-regulation of Bax. We also found that β6-integrin induced 5-FU resistance through the ERK/MAP kinase pathway and the β6-ERK2 direct binding. The results indicate β6-integrin might be a novel therapeutic target in colon cancer therapy.

PKC promotes the migration of colon cancer cells by regulating the internalization and recycling of integrin αvβ6

Recently published studies have suggested that integrin trafficking is necessary to support cell migration, but the role of internalization and recycling of integrin αvβ6 in colon cancer cells remained unclear. In our study, we demonstrated the existence of the integrin cycle and found that inhibition of ERK2 phosphorylation by PD98059 or deletion of the ERK2 direct binding site on the β6 cytoplasmic domain could interrupt the internalization of integrin αvβ6, but had no effect on its recycling. Furthermore, integrin αvβ6 trafficking played a key role in the migration of colon cancer cells towards fibronectin. Activation of PKC significantly accelerated the internalization and recycling of integrin αvβ6, which could facilitate rapid redistribution of integrin αvβ6 and increase cell motility. When colon cancer cells became crowded, the increase in αvβ6 levels at the cell surface was not accompanied by a change in total αvβ6 expression in cell lysates. This change may be due to a redistribution of αvβ6 in cell microstructures and a rapid cellular response towards the demands of migration.

Norcantharidin induces HT-29 colon cancer cell apoptosis through the αvβ6–extracellular signal-related kinase signaling pathway

Norcantharidin has been used as an efficacious anticancer drug in China for many years, but its true mechanism remains poorly understood. Intriguingly, in an in vitro series study of anticancer drugs, we found that norcantharidin can effectively inhibit epithelial tumor cells from expressing integrin αvβ6. Our previous studies have confirmed that integrin αvβ6 is closely relevant to malignant epithelial cell tumor biology behavior, and it can promote cancer cells to invade and metastasize through a special αvβ6–extracellular signal‐related kinase (ERK) direct signaling pathway. In this study, we investigated the relationship between the norcantharidin anticancer mechanism and integrin αvβ6. After HT‐29 colon cancer cells were treated with norcantharidin, cell apoptosis increased remarkably. The expression of αvβ6 and the amount of p‐ERK decreased substantially; simultaneously, the linkage between αvβ6 and ERK was barely detectable. However, the expression of other integrins and the levels of mitogen‐activated protein kinase hardly changed. On these grounds, we presumed that norcantharidin induced HT‐29 colon cancer cell apoptosis through the αvβ6–ERK signaling pathway. This finding elicited a novel strategy for targeting the whole αvβ6–ERK signal pathway, rather than simply blocking the combining site of αvβ6–ERK in colon cancer treatment. (Cancer Sci 2009; 100: 2302–2308)

Interleukin-8 promotes cell migration through integrin αvβ6 upregulation in colorectal cancer

Colorectal cancer (CRC), which is notorious for high morbidity and mortality around the world, shows a predilection for metastasis to liver. Interleukin-8 (IL-8), a chemokine with a defining CXC amino acid motif, has been reported to promote CRC cell migration and is associated with poor prognosis of CRC. However, the underlying molecular mechanism of IL-8-mediated migration remains obscure. In this study, we first demonstrated the cross talk between IL-8 and integrin αvβ6. We analyzed 139 human CRC samples, and found that the immunohistochemical expression of αvβ6 was significantly correlated with expression of IL-8. Furthermore, IL-8 increased the migration through integrin αvβ6 in human CRC cells, and both CXCR1 and CXCR2 were primarily involved during the process. IL-8 upregulated αvβ6 expression in a dose-dependent manner through activation of ERK and Ets-1 signaling pathway. Taken together, our results indicated that IL-8 enhances the migration of CRC cells by increasing αvβ6 integrin expression through the ERK/Ets-1 pathway. Targeting integrin αvβ6 in IL-8 expressing tumors might be a potential therapeutic strategy for CRC patients.

Suppression of integrin αυβ6 by RNA interference in colon cancer cells inhibits extracellular matrix degradation through the MAPK pathway

Integrin αυβ6 plays a very important role in the progression of colon cancer cells and is now defined as a novel, independent prognostic indicator for aggressive colon cancer in humans. Herein, we use the RNA interfering technology to downregulate the expression of αυβ6 in colon cancer cells. Our data demonstrate that plasmid vector based shRNA can effectively down‐regulate αυβ6 expression in protein and mRNA levels. Supression of integrin αυβ6 inhibits the phosphorylation and nonphosphorylation level of ERK1/2, the secretion of uPA, pro‐MMP‐9 and pro‐MMP‐2 in tumor conditioned medium, and more important, inhibits MAPK‐dependent [3H] labeled collagen IV degradation via the plasminogen activation cascade. Our study demonstrates in vitro that supression of integrin αυβ6 inhibits extracellular matrix degradation through the MAPK pathway.

β6 integrin induces the expression of metalloproteinase-3 and metalloproteinase-9 in colon cancer cells via ERK-ETS1 pathway

We previously reported that β6 integrin played an important role in the progression of colon cancer. In this study, we demonstrated that β6 integrin induced the expression of MMP-3/MMP-9 and the invasion of colon cancer cells. Moreover, that function was abolished by the inhibition of ERK/MAPK pathways or knockdown of ETS1, an important transcription factor of MMP genes. Here, we showed that β6 induced phosphorylation of ETS1 via the ERK/MAPK pathways, through which the MMP-3/MMP-9 promoters were stimulated, thereby leading to the up-regulation of MMP-3/MMP-9, and subsequent the invasion of colon cancer cells.

Integrinβ6-Targeted Immunoliposomes Mediate Tumor-Specific Drug Delivery and Enhance Therapeutic Efficacy in Colon Carcinoma

Purpose: Adjuvant chemotherapy is one of the significant treatments for colon cancer in clinic. However, it does not achieve the desired therapeutic efficacy, largely due to chemotherapeutic resistance. Integrinβ6 (ITGB6) is expressed in malignant colonic epithelia, but not in normal epithelia, and is associated with the progression, metastasis, and chemotherapeutic resistance of colon cancer. Accordingly, it is necessary to design therapeutic approaches for efficient and targeted drug delivery into ITGB6-positive cancer cells to improve chemotherapeutic efficacy in colon cancer. Experimental Design: PEGylated liposomes were employed to design ITGB6-targeted immunoliposomes, which have ITGB6 monoclonal antibodies (mAbs) conjugated. We evaluated the ITGB6-targeted immunoliposomes internalization into colon cancer cells and examined 5-fluorouracil (5-FU)–induced cellular apoptosis produced by ITGB6-targeted immunoliposomes+5-FU. In addition, the biodistribution and antitumor efficiency of ITGB6-targeted immunoliposomes were observed in vivo. Results: ITGB6-targeted immunoliposomes enhanced cellular internalization in ITGB6-positive colon cancer cells compared with liposomes. Furthermore, the ITGB6-targeted immunoliposome internalization was dependent on the ITGB6 expression level on cellular surface. ITGB6-targeted immunoliposomes decreased the 5-FU IC50 more than 90% in HT-29 and SW480β6 cells relative to liposomes. Moreover, when loaded with 5-FU, ITGB6-targeted immunoliposomes produced an approximately 1.5-fold higher 5-FU–induced cellular apoptosis rate than liposomes. In vivo, the therapeutic activity of ITGB6-targeted immunoliposomes+5-FU was significantly superior, resulting in 25% to 35% reduction of tumor weight compared with 5-FU or liposomes+5-FU. Conclusions: ITGB6-targeted immunoliposomes provide a highly efficient approach for targeted drug delivery in colon cancer and thus offer the potential of a novel and promising anticancer strategy for clinical therapy. Clin Cancer Res; 21(5); 1183–95. ©2014 AACR.

Protein expression of eIF4E and integrin αvβ6 in colon cancer can predict clinical significance, reveal their correlation and imply possible mechanism of interaction

BackgroundBoth eukaryotic translation initiation factor 4E (eIF4E) and integrin αvβ6 play an important role in the development and progression of cancer. The aim of this study was to investigate the expression of eIF4E and Integrin αvβ6, their clinical significance as well as the two proteins’ correlation in colonic carcinoma tissues.ResultsThe expression levels of eIF4E and integrin αvβ6 were analyzed in colon cancerous and paraneoplastic tissues of 138 cases via tissue microarray (TMA)- immunohistochemistry. And their clinical significance as well as the two proteins’ correlation was also investigated. The expression of eIF4E was significantly associated with clinical TNM stage (P = 0.009), while T stage (P = 0.011) and TNM stage (P = 0.012) were significantly associated with integrin αvβ6 expression. Moderately weak correlation exists between the two proteins (r =0.299, P <0.001). The survival analysis by Kaplan-Meier and Cox regression model showed that protein expression of high eIF4E and positive integrin αvβ6, as independent prognostic factors (RR = 2.417, P = 0.001 and RR = 2.393, P = 0.001), tended to have a significantly poorer 5-year survival rate (P = 0.013 and 0.025, respectively, the log-rank test).ConclusioneIF4E and Integrin αvβ6 were indicators of tumor’s progression and poor prognosis of patients with colon cancer. And the potential signaling loop involving them may provide a helpful therapeutic target in prevention and treatment of colon cancer.