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Pancreatic ductal adenocarcinoma (PDAC) remains one of the most deadly cancers and is expected to become the second leading cause of cancer death by 2030. Despite extensive efforts to improve surgical treatment, limited progress has been made. Increasing evidence indicates that integrin β6 plays a crucial role in carcinoma invasion and metastasis. However, the expression and role of β6 in PDAC remain largely unknown. In the present study, we investigated the expression of β6 in PDAC and its potential value as a prognostic factor and therapeutic target. β6 upregulation was identified as an independent unfavorable prognostic indicator. Integrin β6 markedly promoted the proliferation and invasion of pancreatic carcinoma cells and induced ETS1 phosphorylation in an ERK-dependent manner, leading to the upregulation of matrix metalloprotease-9, which is essential for β6-mediated invasiveness of pancreatic carcinoma cells. Accordingly, small interfering RNA-mediated silencing of integrin β6 markedly suppressed xenograft tumor growth in vivo. Taken together, our results suggest that integrin β6 plays important roles in the progression of pancreatic carcinoma and contributes to reduced survival times, and may serve as a novel therapeutic target for the treatment of PDAC.

Objective To explore the diagnosis of rectal carcinoid tumors and to adopt the best method of treatment. Patients and methods A group of 312 cases of pathologically confirmed rectal carcinoid were analyzed retrospectively. Data were obtained retrospectively from a database of all colorectal malignancies at Qilu Hospital from January 2004 to December 2012. 4072 colorectal malignant tumors and 312 rectal carcinoid tumors were diagnosed. Endoscopic resection was performed on 44 patients, while the other 248 underwent anus partial extended radical polypectomy. We evaluated the clinical manifestations, diagnosis, treatment and follow-ups regarding carcinoids and the relation between tumor diameter and the rate of recurrence or metastasis after surgery. Results There is no recurrence or metastasis after the transanal local resection in 284 cases with the tumor diameter less than 2 cm, 6 months to 7 years' follow-up. While, in 12 cases with the tumor diameter more than 2 cm radical surgery was performed, 8 cases had liver metastases at the time of the diagnosis of rectal carcinoid, 4 cases had no recurrence or metastasis after two and a half years' of follow ups, there is no recurrence or metastasis in 4 cases of multiple rectal carcinoids, whom all underwent radical surgery, follow ups continued for 2 years. Conclusion Early diagnosis and treatment is important for rectal carcinoids, local resection is a simple, safe and effective treatment for carcinoids with a tumor diameter less than 2 cm.

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.

Norcantharidin (NCTD) is an efficacious anti-cancer drug that has been used in China for many years, but its underlying mechanism of action is still not fully understood. In the present study, we found that NCTD could induce morphological changes in colon cancer cells, causing a transition from a spindle-shaped morphology to a typical round or oval shape, which was indicative of a mesenchymal-epithelial transition (MET) process. Next, we investigated the mechanism by which NCTD induced the MET process. Using a transwell assay, we found that NCTD could suppress the migratory and invasive ability of colon cancer cells in a dose-dependent manner. Moreover, NCTD suppressed the expression of integrin αvβ6, MMP-3 and MMP-9 as well as the polymerization of F-actin, further supporting its suppressive effect on migratory and invasive ability. Furthermore, the expression of αvβ6, N-cadherin, vimentin and phosphorylated ERK was decreased, while the expression of E-cadherin was up-regulated. We verified that phosphorylated Ets1 was down-regulated substantially after treatment with NCTD. Taken together, our data demonstrated that NCTD could inhibit the EMT process of colon cancer cells by inhibiting the αvβ6-ERK-Ets1 signaling pathway. This study revealed part of the mechanism through which NCTD could reverse the EMT process in colon cancer.

Integrins play an important role in tumor metastasis induced by vascular endothelial growth factor (VEGF). However, in the case of gastric cancer, the precise role of VEGF in regulating integrin alphavbeta6 is unclear. In this study, we found that most of the alphavbeta6 integrin-positive gastric cancer tissues were also VEGF-positive. Furthermore, when gastric carcinoma cells were exposed to VEGF, expression of alphavbeta6 integrin was up-regulated and the extracellular signal-related kinase (ERK) pathway was activated. When integrin alphavbeta6 was blocked either with beta6 siRNA or anti-alphavbeta6 antibody, the migration of tumor cells normally induced by VEGF, as well as the activation of ERK, were markedly inhibited. Blocking the ERK signaling pathway significantly inhibited cell mobility. Taken together, the data suggest that VEGF is critical to the invasive process in human gastric cancer and that this occurs via up-regulation of integrin alphavbeta6 expression and activation of ERK.

Integrin alphaupsilonbeta6 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 alphaupsilonbeta6 in colon cancer cells. Our data demonstrate that plasmid vector based shRNA can effectively down-regulate alphaupsilonbeta6 expression in protein and mRNA levels. Supression of integrin alphaupsilonbeta6 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 [(3)H] labeled collagen IV degradation via the plasminogen activation cascade. Our study demonstrates in vitro that supression of integrin alphaupsilonbeta6 inhibits extracellular matrix degradation through the MAPK pathway.

To investigate the value of lymph node labeled with carbon nanoparticles in laparoscopic colorectal cancer resection.The clinical data of 53 patients received laparoscopic radical colorectal surgeries in our department from March 2014 to July 2014 was retrospectively analyzed.Among these patients, carbon nanoparticles were injected into the periphery of the tumor under colonoscopy 1-3 days before the operation (the nanoparticle group) in 26 patients, while 27 patients received operation directly (the control group).The number of cleared lymph nodes, tiny lymph nodes (5 mm), dyed lymph nodes, and lymph node metastatic rate were compared between the two groups.The two groups had no statistical difference in basic characteristics; 434 and 340 lymph nodes were dissected in the nanoparticle group and control group respectively.The average number of cleared lymph nodes(16.7 ± 3.2) in the nanoparticle group was significantly higher than that of the control group(12.6 ± 2.3) (P0.001). Besides, both the average number and ratio of cleared tiny lymph nodes in the nanoparticle group were significant higher than those of the control group (P0.001). Moreover, the rate of less than 12 detected lymph nodes in the nanoparticle group was markedly lower than that of the control group (0 vs 33.3%, P=0.001).There was no statistical difference in lymph node metastatic rate between the two groups (P=0.693).Application of lymph node labeled with carbon nanoparticles in laparoscopic colorectal cancer surgery could instruct lymph nodes dissection, improve lymph node detection rate, reduce tumor residual rate, improve the accuracy of pathological staging, and guide the postoperative adjuvant therapy.

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.

High expression of matrix metalloproteinase-9 (MMP-9) was found to be correlated with tumor progression and poor prognosis in a variety of carcinomas. However, few studies have investigated the role of MMP-9 in human hilar cholangiocarcinoma. In this study, a total of 58 patients with hilar cholangiocarcinoma who underwent curative resection were included in this study. The expression of MMP-9 was analyzed by immunohistochemistry using the streptavidin peroxidase complex method. The correlation of MMP-9 overexpression with clinicopathological features and survival time of patients was investigated. The results showed that MMP-9 overexpression was prominent in cancer cells and mainly localized in the cytoplasm. MMP-9 overexpression was observed in 46.5% tumors, which showed no correlation with clinicopathological parameters. Patients with high MMP-9 expression had a significantly poorer overall survival rate than those with negative or low MMP-9 expression (P = 0.038). Multivariate analysis confirmed that MMP-9 overexpression was an independent prognostic factor (P = 0.007). In conclusion, overexpression of MMP-9 is a valuable independent prognostic indicator in hilar cholangiocarcinoma.

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.

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.

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.

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.

Integrin alphavbeta6 is up-regulated in a variety of human carcinomas and plays a crucial role in tumor invasion and metastasis. However, the function of alphavbeta6 in pancreatic carcinoma and its potential role in gemcitabine resistance remain unknown.Small interfering RNA (siRNA) targeting alphavbeta6 was constructed and transfected into PANC-1 cells. Effects of alphavbeta6 knockdown on cell proliferation, invasion, cell cycle progression, apoptosis and chemosensitivity to gemcitabine were investigated.Expression of alphavbeta6 in PANC-1 cells was markedly suppressed by siRNA. Silencing of alphavbeta6 expression significantly inhibited cell proliferation and invasiveness, resulted in cell cycle arrest, and induced cell apoptosis. More importantly, alphavbeta6 knockdown enhanced chemosensitivity to gemcitabine and increased gemcitabine-induced caspase-mediated apoptosis.These findings suggest a novel mechanism by which alphavbeta6 contributes to pancreatic carcinoma progression. The combination of alphavbeta6 silencing and gemcitabine treatment may provide an effective therapeutic strategy for highly resistant pancreatic carcinoma.

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 alphavbeta6. Our previous studies have confirmed that integrin alphavbeta6 is closely relevant to malignant epithelial cell tumor biology behavior, and it can promote cancer cells to invade and metastasize through a special alphavbeta6-extracellular signal-related kinase (ERK) direct signaling pathway. In this study, we investigated the relationship between the norcantharidin anticancer mechanism and integrin alphavbeta6. After HT-29 colon cancer cells were treated with norcantharidin, cell apoptosis increased remarkably. The expression of alphavbeta6 and the amount of p-ERK decreased substantially; simultaneously, the linkage between alphavbeta6 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 alphavbeta6-ERK signaling pathway. This finding elicited a novel strategy for targeting the whole alphavbeta6-ERK signal pathway, rather than simply blocking the combining site of alphavbeta6-ERK in colon cancer treatment.

Pancreatic duct stone is thought not only to be the cause of abdominal pain but also to be a risk factor for pancreatic cancer. Several treatment options have been implemented in the treatment of pancreatic duct stones. Stone location is a critical factor in selecting treatment. We present the results of 27 endoscopic treatments and 35 surgical treatments performed in three hospitals at a single university between January 2000 and January 2005. The results were compared retrospectively in terms of success rate of stone removal, length of hospital stay, complications, pain relief, and changes of pancreatic functions. In our study, endoscopy resulted in a similar success rate of stone removal and short-term pain relief rate as the surgical approach and with a shorter length of hospital stay. However, the surgical group had a more favorable long-term clinical result, as well as a lower number of hospital readmissions at the 5-year follow-up point. Based on long-term results, surgical treatment is more effective than endoscopy.