Li Jen Kuo

Nicotine Enhances Colon Cancer Cell Migration by Induction of Fibronectin

BackgroundLong-term cigarette smoking increases the risk of colorectal cancer mortality. Tobacco’s addictive toxin, nicotine, was reported to increase DNA synthesis of colon cancer cells. Because metastasis is the major cause of cancer death, the influence of nicotine on the migration of colon cancer cells remains to be determined.MethodsThe influence of nicotine on the migration of colon cancer cells was evaluated using transwell assay. Nicotine receptor-mediated migration was studied by using both inhibitors and small interfering RNA (siRNA). The role of COX-2 signal was studied using pharmacological inhibitors. The expression of epithelial mesenchymal transition (EMT) marker and COX-2 signal was evaluated using real-time polymerase chain reaction (PCR).ResultsNicotine enhanced DLD-1 and SW480 cell migration in a dose-dependent manner. We used inhibitors and siRNA to demonstrate that α7-nAChR mediates nicotine-enhanced colon cancer cell migration and upregulates fibronectin expression, which is involved in nicotine-enhanced migration. Furthermore, COX-2 signal was induced by nicotine treatment and is involved in nicotine-enhanced fibronectin expression.ConclusionsNicotine, tobacco’s additive toxin, enhances colon cancer metastasis through α7-nAChR and fibronectin—a mesenchymal marker for epithelial mesenchymal transition. Furthermore, COX-2 signal was involved in the induction of fibronectin. Therefore, smoking may play role in the progression of colon cancer.

Nicotine Promotes Cell Migration Through Alpha7 Nicotinic Acetylcholine Receptor in Gastric Cancer Cells

BackgroundThe objective was to study the mechanism of nicotine-enhanced migration of gastric cancer cells. Long-term cigarette smoking increases the risk of gastric cancer mortality. Tobacco-specific mitogen, nicotine, was reported to correlate with cancer progression on gastric cancer. Since metastasis is the major cause of cancer death, the influence of nicotine on the migration of gastric cancer cells remains to be determined.Materials and MethodsThe influence of nicotine on migration of gastric cancer cells was evaluated by transwell assay and wound-healing migration assay. Receptor-mediated migration was studied by both inhibitor and small interfering RNA.ResultsAlpha7 nicotinic acetylcholine receptor, alpha7-nAChR, was identified in gastric cancer cell lines, AGS cells. Nicotine enhanced AGS cell migration in transwell assay and wound-healing migration assay in a dose-dependent manner. We used inhibitor and siRNA to demonstrate that alpha7-nAChR mediated nicotine-enhanced gastric cancer cell migration through downregulation E-cadherin and upregulation ZEB-1 and snail.ConclusionsTobacco-specific mitogen, nicotine, enhanced gastric cancer metastasis through alpha7-nAChR and suppression of E-cadherin level—one of the hallmarks of epithelial to mesenchymal transition. Therefore, patients with gastric cancer should avoid smoking.

Oncological and functional outcomes of intersphincteric resection for low rectal cancer

BACKGROUND The intersphincteric resection technique has been used to extend the opportunity for sphincter preservation in patients with very low rectal cancer. The aim of this study is to assess the long-term oncological and functional outcomes of intersphincteric resection. METHODS Patients with extraperitoneal rectal cancer were treated and retrospectively chart reviewed. The oncological and functional outcomes were evaluated. Comparisons of the overall disease-free survival and recurrence were analyzed for the different surgical procedures. RESULTS From July 2002 to August 2009, 162 patients with extraperitoneal rectal cancer were retrospectively chart reviewed. One-hundred one patients (62.3%) underwent low anterior resection, 26 patients (16%) received radical proctectomy and intersphincteric resection with coloanal anastomosis, and 23 (14.2%) had abdominoperineal resection. The sphincter preservation rate was 80%. In the intersphincteric resection group, overall survival rates at 3 and 5 y were 83% and 83%, and disease-free survival at 3 and 5 y were 82% and 76%, respectively. The mean stool frequency was 4.7 per 24 h. There were 38.1% of patients suffering from stool fragmentation, and 23.8% had nocturnal defecation. About one-third of the patients required antidiarrheal medications. Overall, 90.8% of patients were satisfied with the functional results of surgery. CONCLUSIONS Our data show intersphincteric resection for low rectal cancer is feasible and safe. Preoperative radiotherapy may negatively affect symptom-specific quality of life.

Glucose-Regulated Protein 78 (GRP78) Mediated the Efficacy to Curcumin Treatment on Hepatocellular Carcinoma

BackgroundGlucose-regulated protein 78 (GRP78) plays an important role in the therapeutic treatment and progression of cancer. However, little is known about the effect of GRP78 expression to curcumin in hepatocellular carcinoma (HCC).Materials and MethodsIn this study, we generated GRP78 knockdown cells (GRP78KD) by a short interfering RNA (siRNA) technique. The antiproliferation effects of curcumin were determined by MTT assay, TUNEL assay, and cell cycle determination.ResultsWe found that GRP78KD cells were more resistant to curcumin treatment compared with the parental cells in MTT assay. The apoptosis cell population was increased in scrambled-siRNA cells treated with curcumin compared with GRP78KD cells in cell cycle distribution and TUNEL assays. Finally, we found that knocking down GRP78 causes resistance to curcumin treatment through the suppression of caspase-3 and caspase-8 expression levels.ConclusionsWe conclude that the expression level of GRP78 may contribute to the therapeutic effect of curcumin on HCC cells.

Silencing of Glucose-Regulated Protein 78 (GRP78) Enhances Cell Migration Through the Upregulation of Vimentin in Hepatocellular Carcinoma Cells

BackgroundGlucose-regulated protein 78 (GRP78) plays an important role in embryonic development and cancer progression. However, there is little information regarding the regulation of GRP78 in hepatocellular carcinoma (HCC) metastasis.MethodsWe used RNA silencing and cDNA expression vectors to manipulate target gene expression in HCC cells. The transwell migration assay and xCelligence biosensor system were applied to determine the proliferatory and migratory ability of the HCC cells.ResultsIn this study, we found that GRP78 silencing enhanced cell migration in both HepJ5 and Mahlavu cells. Overexpressed GRP78 in skHep1 cells suppressed the migratory ability. In the insight mechanism dissection for GRP78-mediated cancer migration, we found that downregulation of GRP78 caused the increase of vimentin expression on HCC cells. Suppressed vimentin expression also decreased the migratory ability on HCC, indicating that vimentin expression levels modulated the cell migratory ability.ConclusionWe found that silencing GRP78 in HCC cells may enhance cell migration through the increase of vimentin expression.

Can we predict pathologic complete response before surgery for locally advanced rectal cancer treated with preoperative chemoradiation therapy

BackgroundPathologic complete response has been proven to have oncological benefits for locally advanced rectal cancer treated with chemoradiation therapy. The aims of this study are to analyze and determine the factors to predict pathologic complete response for patients treated with preoperative neoadjuvant therapy.MethodsPatients with biopsy-proven, locally advanced rectal cancer were treated neoadjuvantly followed by radical surgical resection. Tumors were re-assessed after completing chemoradiation, including pelvic magnetic resonance images, colonoscopic examination, and re-biopsy. The results of examination were compared with the final pathologic status.ResultsA retrospective chart review of 166 patients was conducted. Twenty-five patients (15.1%) had pathologic complete response after chemoradiation. The 5-year overall survival rates were better in the complete response group than the residual tumor group (91.1% vs. 70.8%; P = 0.047), and there were also significant differences in the 5-year disease-free survival rates between these two groups (91.1% vs. 70.2%; P = 0.027). The prediction rates for pathologic complete response by re-biopsy, magnetic resonance images, and colonoscopy were 21.4%, 33.3%, and 53.8%, respectively. In addition, when we further combine the results of colonoscopic findings and re-biopsy, the prediction rate for pathologic complete response reached 77.8% (P = 0.009).ConclusionsCombining the results of the re-biopsy and post-treatment colonoscopic findings, we can achieve a good prediction rate for pathologic complete response. Post-treatment magnetic resonance images are not useful tools in predicting tumor clearance following chemoradiation.

Survivin-Mediated Cancer Cell Migration Through GRP78 and Epithelial-Mesenchymal Transition (EMT) Marker Expression in Mahlavu Cells

BackgroundSurvivin has multiple functions during the progression of cancer. However, the role of survivin in the progression and metastasis of hepatocellular carcinoma (HCC) remains unknown.Materials and MethodsSurvivin expression in HCC cells (Mahlavu and Hep3B) was assessed using reverse transcription real-time PCR and Western blot analyses. In addition, survivin expression in HCC cells was manipulated using small interfering RNA (siRNA) or overexpression and proliferation and transwell migration assays were performed to monitor the effect of manipulated survivin expression on the growth rate and migratory ability of the transfected cells.ResultsAmong the HCC cell lines tested, we found high endogenous expression of survivin mRNA and protein in Mahlavu cells. After silencing survivin expression in Mahlavu cells, there was a dramatic decrease in the cell growth rate and an increase in the metastatic potential of the cells. Overexpression of survivin in Hep3B cells suppressed the ability of the cell to migrate. The mechanism of enhanced cell migration caused by decreased survivin expression is mediated through the downregulation of glucose-regulated protein 78 (GRP78) and the upregulation of the epithelial-mesenchymal transition (EMT) marker, vimentin.ConclusionsSurvivin may mediate metastasis in HCC. The knockdown of survivin expression may enhance cancer metastasis through the downregulation of GRP78 and upregulation of vimentin expression.

Glucose-regulated protein 78 silencing down-regulates vascular endothelial growth factor/vascular endothelial growth factor receptor 2 pathway to suppress human colon cancer tumor growth.

BACKGROUND Up to 20% of colorectal cancer (CRC) is diagnosed with distant metastasis. The combination of chemotherapy with anti-vascular endothelial growth factor (VEGF) antibody can improve patient survival. Glucose-regulated protein 78 (GRP78) has an important role in cancer progression, but little is known about its role in VEGF production in CRC. The aim of this study was to explore the mechanism of GRP78 in two human colon cancer cell lines. METHODS We first checked the expression of GRP78 in human normal and colon cancer tissues and two colon cancer cell lines. Glucose-regulated protein 78 was knocked down using GRP78 small interfering RNA (siRNA) in HT29 and DLD-1 cells. We examined knockdown cells by the cell growth kinetics in vitro and tumor growth rate in vivo, respectively. We also investigated the effect of GRP78 siRNA on the expression of hypoxia inducible factor (HIF-1α), VEGF, and VEGF receptor 2 (VEGFR2). RESULTS Compared with their adjacent normal tissue, we detected high expression levels of GRP78 of surgically removed colon cancer tissues. Using GRP78 siRNA, we reduced the expression of GRP78 in HT29 and DLD-1 cells. The GRP78 knockdown cells had a lower proliferation rate with fewer colony-forming units in vitro and produced smaller tumors in vivo. In dissecting the mechanism underlying the reduced cell growth, we found that the down-regulation of GRP78 decreased the production of HIF-1α, VEGF, and VEGFR2 and suppressed angiogenesis. CONCLUSIONS Silencing GRP78 not only inhibits tumor, but also decreases the expression of VEGF and VEGFR2. Collectively, therapy targeting for GRP78 may inhibit the formation of colon cancer tumors via the HIF-1α/VEGF/VEGFR2 pathway.

NNK enhances cell migration through α7-nicotinic acetylcholine receptor accompanied by increased of fibronectin expression in gastric cancer.

BackgroundIn this study, we intended to dissect the mechanism of 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-enhanced migration of gastric cancer. Smoking has been defined as a risk factor for gastric cancer. Tobacco-specific carcinogen, NNK, was reported to enhance cancer progression in gastric cancer. Currently, metastasis is the major issue for clinical cancer therapy, but the influence of NNK on the migration of gastric cancer remains to be determined.MethodsThe expression of nicotinic receptor in gastric cancer cells was identified by real-time polymerase chain reaction and Western blotting. The influence of NNK on migration of gastric cancer cells was evaluated by the transwell migration assay system. Receptor-mediated migration was studied by both inhibitor and small interfering RNA.ResultsAlpha7 nicotinic acetylcholine receptor, alpha7-nicotinic acetylcholine receptor (nAChR), was identified higher than alpha9-nAChR in gastric cancer cell lines, AGS cells. NNK enhanced significantly gastric cancer cell migration in transwell assay. We used inhibitor and siRNA to demonstrate that alpha7-nAChR mediated NNK-enhanced gastric cancer cell migration and upregulation of fibronectin were involved in NNK-enhanced migration of gastric cancer cells. Finally, we found that silenced fibronectin expression level inhibited the migratory ability in AGS cells.ConclusionsNNK enhanced gastric cancer metastasis through alpha7-nAChR and fibronectin—one of the hallmarks of epithelial mesenchymal transition.

Knockdown survivin expression reduces the efficacy of curcumin treatment in hepatocellular carcinoma cells

BackgroundSurvivin is a potential therapeutic target for cancer. Increased survivin expression promotes cell survival and therapeutic resistance. However, there is little information regarding whether the expression level of survivin affects curcumin treatment in hepatocellular carcinoma (HCC).MethodsSurvivin expression was suppressed in HCC cells using a short interfering RNA (siRNA) technique. The anticancer effects of curcumin were examined using a biosensor system, MTT assay, TUNEL assay, and cell cycle analysis.ResultsCurcumin resistance developed in cells with suppressed survivin, in contrast to the parental cells, as determined by survival assays. Cell cycle analysis and TUNEL assays revealed that the apoptotic cell population was increased in the scrambled-siRNA cells treated with curcumin compared with the survivin-siRNA cells. Suppression of survivin expression resulted in curcumin resistance via the modulation of Bcl-2 and Bax expression.ConclusionsWe conclude that the expression levels of survivin may mediate the therapeutic efficacy of curcumin in HCC cells.