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Background: The most widely used noninvasive screening tests for colorectal cancer are fecal occult blood tests. Stool DNA test was developed in recent years. However, direct comparative analyses of these tests within the same population are still sparse. Methods: A total of 2,842 participants who visited outpatient clinics or cancer screening centers were enrolled. Stool DNA test-I (KRAS, BMP3, NDRG4, and hemoglobin immunochemical tests), stool DNA test-II (SDC2 and SFRP2 tests), and fecal immunochemical test (FIT) alone were performed and colonoscopy was used as the gold standard among 2,240 participants. Forty-two and 302 participants had colorectal cancer and advanced adenomas (AA), respectively. Results: The sensitivity for colorectal cancer of stool DNA test-I, -II, and FIT was 90.5%, 92.9%, and 81.0%, respectively. The sensitivity for advanced neoplasm (AN; colorectal cancer plus AA) of stool DNA test-I, -II, and FIT was 34.9%, 42.2%, and 25.9%, respectively. The specificity of stool DNA test-I, -II, and FIT was 91.4%, 93.3%, and 96.8%, respectively, among those with negative results on colonoscopy. When the specificity of FIT was adjusted to match that of stool DNA tests by changing the threshold, no significant difference was seen in the sensitivities among the three tests for detecting colorectal cancer. For AN, the sensitivity of FIT was higher than DNA test-I and similar to DNA test-II under the same specificities. Conclusions: There was no significant advantage of the two stool DNA tests compared with FIT in detecting colorectal cancer or AN in this study. Impact: Our findings do not support extensive use of stool DNA tests instead of FIT.

The Asia-Pacific Colorectal Screening (APCS) scoring system was developed to stratify the risk of colorectal advanced neoplasm (AN). We aimed to evaluate the performance of the APCS score combined with a stool DNA test used for colorectal cancer screening.A total of 2842 subjects who visited outpatient clinics or cancer screening centers were enrolled. Age, sex, smoking status, and family history were recorded and APCS scores were calculated in 2439 participants. A stool DNA test (SDC2 and SFRP2 tests) and fecal immunochemical test (FIT) were performed and colonoscopy was used as the gold standard among 2240 subjects who completed all study procedures. We used a threshold of 4.4 μg/g for the FIT, in addition to the manufacturer's recommended threshold of 20 μg/g to match the specificity of a stool DNA test.Based on the APCS score, 38.8% (946 of 2439) of the subjects were categorized as high risk, and they had a 1.8-fold increase in risk for AN (95% CI, 1.4-2.3) compared with low and moderate risk. The APCS combined with the stool DNA test detected 95.2% of invasive cancers (40 of 42) and 73.5% of ANs (253 of 344), while the colonoscopy workload was only 47.1% (1056 of 2240). The sensitivity for AN of APCS combined with stool DNA test was significantly higher than that of APCS combined with FIT (73.5% vs 62.8% with FIT cut-off value of 20 μg/g, and 73.5% vs 68.0% with FIT cut-off value of 4.4 μg/g; both P.01).The APCS score combined with a stool DNA test significantly improved the detection of advanced colorectal advanced neoplasms, while limiting colonoscopy resource utilization (Chictr.org.cn, ChiCTR-DDD-17011169).

Background Colorectal endoscopic submucosal dissection (ESD) is a challenging operation because it is often difficult to attain good visualization of the submucosal layer. Lots of traction methods have been developed to facilitate submucosal dissection, but still not widely applied. Therefore, we designed a new traction device "traction ring". This pilot study is to evaluate if traction ring is feasible and safe for colorectal ESD. Methods We retrospectively analyzed 20 patients with colorectal lesions who had undergone traction ring assisted ESD. The main outcome was the rate of en bloc resection, R0 resection rate, procedure time, resection time, intraoperative and postoperative complications. Results The median procedure time was 74.5 min (range 35–269 min.). The median resection time was 55 min (range 25–209 min.). The application of the traction system accounting for only 2.7% of the whole procedure time. Rate of en bloc resection was 95% (19/20). Rate of R0 resections was 90% (18/20). All traction rings were successfully settled and retrieved. No serious excessive intraoperative bleeding was observed. One patient was found perforation after treatment, no further intervention was required. No delayed complications were observed within one month after the operation. Conclusions This retrospective study demonstrated that the new countertraction method (traction ring) may become a safe, effective and simple way to assist ESD for colorectal lesions.

Epithelial-mesenchymal transition (EMT) is critical in the progression of numerous types of carcinoma, and endows invasive and metastatic properties upon cancer cells. The tumor microenvironment facilitates tumor metastasis to distant organs. Various signaling pathways contribute to this process. In the present study, SW480 colon adenocarcinoma cells were treated with transforming growth factor-β1 (TGF-β1; 10 ng/ml) and tumor necrosis factor-α (TNF-α; 20 ng/ml), alone or in combination, for 72 h, and EMT was assessed using immunofluorescence, western blot analysis and migration assays. The functions of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK) and nuclear factor-κB (NF-κB) pathways in EMT were examined. It was demonstrated that the cooperation of TGF-β1 and TNF-α signaling promoted the morphological conversion of the SW480 cells from an epithelial to a mesenchymal phenotype. Furthermore, simultaneous exposure to TNF-α and TGF-β1 downregulated the expression of E-cadherin (an epithelial marker) and increased the expression of N-cadherin and vimentin (mesenchymal markers). Additionally, the migratory capacity of the SW480 cells increased. The inhibition of p38 and ERK signaling exhibited no effect on EMT, whereas the inhibition of inhibitor of NF-κB kinase subunit β blocked the EMT induced by TGF-β1 and TNF-α. In conclusion, the results of the present study demonstrated that TNF-α and TGF-β1 synergistically promoted EMT in SW480 cells via the NF-κB pathway, independent of p38 activation and ERK1/2 signaling. These results suggest a novel function of TGF-β1 and TNF-α during EMT in colon carcinoma and, thus, provide insights into potential therapeutic interventions.

Objectives To investigate the efficacy and safety of premedication with simethicone/pronase during esophagogastroduodenoscopy (EGD) with sedation. Methods 610 patients were randomly allocated to two groups based on the type of premedication given. The premedication used in the control group was 10ml of lidocaine hydrochloride mucilage (LHM, N=314) and the premedication used in the intervention group was 80mL of simethicone/pronase solution plus 10ml of lidocaine hydrochloride mucilage (SP/LHM, N=296). The EGD was performed under sedation. The visibility scores, number of mucosal areas that need to be cleansed, water consumption for cleansing, time taken for the examination, diminutive lesion, pathological diagnosis, patients’ gag reflex and the oxygenation (pulse oximetry) were recorded. Results The SP/LHM has significantly lower total visibility score than the LHM (7.978±1.526 vs 6.348±1.097, p

Background The effectiveness in surveillance colonoscopy largely depends on the quality of bowel preparation. We aimed to investigate the quality of bowel preparation segmentally and its effect on Adenoma Detection Rate (ADR) and Advanced Adenoma Detection Rate (AADR) at corresponding bowel segments. Methods This is a single-centered and cross-sectional study. A consecutive of 5798 patients who underwent colonoscopy examination were included. Bowel preparation was evaluated based on Bowel Bubble Scale (BBS) in general and Boston Bowel Preparation Scale (BBPS) in each segment (right side, transverse and left side of colon) and total BBPS scores. The quality of bowel preparation was correlated with ADR and AADR. Results Four thousand nine hundred forty colonoscopies (14,820 bowel segments) were included in the final analysis. In which 30.9% scored 3, 57.5% scored 2, 11.2% scored 1 and 0.4% scored 0 on basis of BBPS. For each score, ADR were 10.8, 7.7, 4.9 and 3.2%, respectively; whereas AADR were 4.5, 2.8,1.8 and 1.6% (P

Background Detecting gastric cancer in the early stage is the key factor in reducing cancer mortality. Endoscopists can now detect early cancer with the aid of advanced imaging in endoscopy. A major technical obstacle in achieving a good quality of endoscopic examination of the gastric mucosa is the presence of foam and mucus over the mucosal surface. Pronase has become a common anti-mucus agent used for improving visibility during upper gastrointestinal endoscopy examination, especially in eastern Asia. While N-acetylcysteine (NAC) can serve as an alternative mucolytic agent more economically. The aim of this study is to investigate the efficacy and cost-benefit of premedication with NAC during esophagogastroduodenoscopy (EGD). Methods We enrolled 1,200 patients and randomly allocated them into 4 groups with different types of premedication. Premedication used in regular group (RG) was 10 mL lidocaine hydrochloride mucilage (LHM) and in pronase+simethicone group (P+S) was 60 mL pronase/simethicone solution plus 10 mL LHM. Meanwhile, 60 mL NAC600 mg/simethicone solution plus 10 mL LHM and 60 mL NAC1200 mg/simethicone solution plus 10 mL LHM were given to the patients in NAC600+simethicone group (NAC600+S) and NAC1200+simethicone group (NAC1200+S), respectively. We recorded visibility scores, times of cleaning, time taken for examination, diminutive lesions and pathological diagnosis. Cost-benefit of premedication was analyzed. Results The visibility of NAC600+S and NAC1200+S are significantly better than RG, although P+S exhibited the lowest total visibility score and shortest procedure duration (figure 1). Times of cleaning was remarkably decreased in NAC600+S and NAC1200+S compared to RG, but was inferior to P+S. There is no significant difference in detection rate of diminutive lesions and pathological diagnosis. Cost-benefit analysis has shown that net medical yield of NAC/simethicone is higher than that of pronase/simethicone. Conclusions NAC can not only facilitate the visibility during EGD, but be more cost-beneficial. It should be recommended as a good alternative premedication to pronase during EGD, especially in developing countries and regions.

Sporadic tumors of the duodenal papilla are rare, with a prevalence of 0.04% to 0.12% in autopsies [1], most of which are adenomas histologically [2].

Background. Economic disparity contributes to the variation of intestinal obstruction (IO) etiologic spectrum. Clarifying the etiology distribution in local regions can help to unravel IO and promote early diagnosis, henceforth making sure standardized therapeutic interventions. Methods. Medical data of 4908 inpatients diagnosed with IO admitted to the General Hospital of Ningxia Medical University between January 2004 and December 2013 were recruited and analyzed retrospectively. The associated profiles included demographic features, clinical manifestations, and previous therapeutic operations. Results. 4908 cases of intestinal obstruction were identified during the period of study. It denoted that the hospitalization rate of IO has maintained upward momentum; the top four causes of IO were adhesion, tumor, intussusception, and hernias. These covered up nearly 80% of the total constitution. Among them, adhesive intestinal obstruction accounted for 45.17%, malignant bowel obstruction for 21.09%, intussusception for 8.72%, and hernia for 4.73%; abdominal surgery constituted for the majority (78.62%) of adhesive obstruction. The followed up analysis also found that appendectomy accounted for the biggest percentage, 28% of operation cases. Malignant bowel obstruction can have a rate of 96.43% in 1035 cases led by tumor lesions. Of which, the primary intestinal malignant tumor accounted for 68.64% and metastatic tumors for 31.36%. Nearly 50% occurred in the large intestine. The overall mortality of all 4908 cases was 4.7%. Conclusion. The hospitalizations of IO delineated an increasing trend. Adhesion was the main etiology in IO. The odds of malignant bowel obstruction was increasing in the proportion of IO. There were some differences towards the etiologic spectrum compared with western countries.

Background Calcyclin Binding Protein/(Siah-1 interacting protein) (CacyBP/SIP) acts as an oncogene in colorectal cancer. The nuclear accumulation of CacyBP/SIP has been linked to the proliferation of cancer cells. It has been reported that intracellular Ca2+ induces the nuclear translocation of CacyBP/SIP. However, the molecular mechanism of CacyBP/SIP nuclear translocation has yet to be elucidated. The purpose of this study was to test whether the Ca2+-dependent binding partner S100 protein is involved in CacyBP/SIP nuclear translocation in colon cancer SW480 cells. Methods The subcellular localization of endogenous CacyBP/SIP was observed following the stimulation of ionomycin or BAPTA/AM by immunofluorescence staining in SW480 cells. S100A6 small interfering RNAs (siRNA) were transfected into SW480 cells. Immunoprecipitation assays detected whether S100 protein is relevant to the nuclear translocation of CacyBP/SIP in response to changes in [Ca2+]i. Results We observed that endogenous CacyBP/SIP is translocated from the cytosol to the nucleus following the elevation of [Ca2+]i by ionomycin in SW480 cells. Co-immunoprecipitation experiments showed that the interaction between S100A6 and CacyBP/SIP was increased simultaneously with elevated Ca2+. Knockdown of S100A6 abolished the Ca2+ effect on the subcellular translocation of CacyBP/SIP. Conclusion Thus, we demonstrated that S100A6 is required for the Ca2+-dependent nuclear translocation of CacyBP/SIP in colon cancer SW480 cells.

Recent gene-profiling analyses showed significant upregulation of the folate hydrolase (FOLH1) gene in the affected intestinal mucosa of patients with inflammatory bowel disease (IBD). The FOLH1 gene encodes a type II transmembrane glycoprotein termed glutamate carboxypeptidase II (GCPII). To establish that the previously reported increased gene expression was functional, we quantified the glutamate carboxypeptidase enzymatic activity in 31 surgical specimens and report a robust 2.8- to 41-fold increase in enzymatic activity in the affected intestinal mucosa of IBD patients compared with an uninvolved area in the same patients or intestinal mucosa from healthy controls. Using a human-to-mouse approach, we next showed a similar enzymatic increase in two well-validated IBD murine models and evaluated the therapeutic effect of the potent FOLH1/ GCPII inhibitor 2-phosphonomethyl pentanedioic acid (2-PMPA) (IC50 = 300 pM). In the dextran sodium sulfate (DSS) colitis model, 2-PMPA inhibited the GCPII activity in the colonic mucosa by over 90% and substantially reduced the disease activity. The significance of the target was confirmed in FOLH1-/- mice who exhibited resistance to DSS treatment. In the murine IL-10-/- model of spontaneous colitis, daily 2-PMPA treatment also significantly reduced both macroscopic and microscopic disease severity. These results provide the first evidence of FOLH1/GCPII enzymatic inhibition as a therapeutic option for IBD.

Introduction : The incidence of ulcerative colitis has increased tremendously over the past few decades, and caused much more attention in China. Several studies have revealed that both environmental and genetic factors play crucial roles in the formation and development of this disease. Among the environmental factors, the smoking condition is highly significant. Although current smoking has been associated with a protective effect on both the development and progression of ulcerative colitis (UC), the clinical characteristics of UC patients with current smoking in China is still unclear. Aim : To clarify the relationship between current smoking and the UC in the northwest of China, patients diagnosed with ulcerative colitis in the General Hospital of Ningxia Medical University from 2003.03 to 2012.09 were assessed. Material and methods : Data were collected about clinical features, cigarette smoking conditions, disease location, and therapeutic requirements. A total of 421 patients were included in this study, at diagnosis, 341 (81%) patients were non-smokers, and the current smokers amounted to 80 (19%). Results : As for disease location, there were no differences between the current smokers and non-smokers regarding proctitis and extensive colitis, but the current smokers had less left-sided colitis than non-smokers (p = 0.049). Based on the Modified Mayo score, heavier smokers had lower scores than other smokers and non-smokers. For the therapeutic requirements, current smokers needed fewer corticosteroids than non-smokers (p = 0.048). Conclusions : We found that current smoking is closely associated with a protective factor for UC.

Background In China, the incidence of Inflammatory bowel disease (IBD) has shown a significant growth trend. Analysis of the epidemiology, clinical manifestations, diagnostic means, and treatment of IBD will further improve the clinician's understanding of IBD, improve knowledge and further enable early diagnosis and standardized therapeutic management. The purpose of this study was to analyze the clinical characteristics of IBD inpatients in General Hospital of NingXia Medical University over a 12-year period to identify trends in clinical and epidemiological features, clinical manifestations, and treatment programs. Methods By excluding188 patients with incomplete information or incompatible with the 2012 Guidlines cases, we retrospectively analyzed the case records of 567 inpatients with a diagnosis of IBD admitted to the General Hospital of NingXia Medical University between January 2002 and December 2014. The clinical epidemiological features, clinical manifestations, diagnostic methods, and therapeutic status were analyzed. Results Over the study period, IBD hospitalization rates in 2002 and 2014 groups was 1.96 % and 4.05 %, increased 2.07 times. Of 567 cases of IBD, 483 (85.19 %) cases were categorized as ulcerative colitis (UC) and 84 as Crohn’s disease (CD) (14.81 %). Total male cases were 321 (56.61 %). Mean age of cases was 49.06 ± 14.92 years for UC and 44.84 ± 14.67 years for CD. The majority of UC was located in the colon, with a moderate level of disease activity. A combination of clinical manifestations and colonoscopy was mostly used to make a diagnosis; relatively the rate of pathological diagnosis was low, with a small proportion of patient’s diagnosed based on radiology. Treatment with SASP/5ASA and steroids was applied to the majority of inpatients and 47.83 % were treated with antibiotics; in contrast, only 1.86 % cases were treated with immunosuppressive therapy. Conclusions An increasing trend of admissions for IBD can be observed in our study; there are some differences in clinical features and treatment compared with Western countries, and further research into this is required.

Cyclooxygenase-2 (COX-2), the key enzyme in prostaglandin synthesis, is often over-expressed in human gastric cancer. Recently, 15-hydroxyprostaglandin dehydrogenase [NAD+] (15-PGDH), the key enzyme in prostaglandin degradation, was found to be down-regulated in human gastric cancer tissues, but little is known about its role in gastric tumorigenesis. In this study, expression plasmids containing 15-PGDH siRNA were constructed and transfected into the gastric cancer cell line MKN45, which expresses endogenous 15-PGDH at a high level. The 15-PGDH gene was also transfected into the gastric cancer cell line SGC7901, which expresses endogenous 15-PGDH at a low level. When compared with the empty vector transfectant, MKN45 cells stably transfected with the 15-PGDH siRNA plasmid had a significantly increased proliferation rate. In contrast, SGC7901 cells stably transfected with the 15-PGDH cDNA had a significantly decreased growth rate. Furthermore, increased expression of 15-PGDH suppressed clone formation of gastric cancer cells in plate and soft agar colony formation assays in vitro and suppressed tumor formation in athymic nude mice in vivo. Stable silencing of 15-PGDH in gastric cancer cells also enhanced cell cycle entry in vitro. These results demonstrate for the first time that 15-PGDH acts as a tumor suppressor in human gastric cancer and provide further validation for 15-PGDH as a potential therapeutic target for human gastric cancer.

Multidrug resistance (MDR) is a major impediment to the effective chemotherapy of many human malignancies. Although much effort has been devoted to develop new drugs for overcoming MDR, until now, still no useful method of reversing MDR, suitable for clinical use, has emerged from this large quantity of work. Some researchers have reported that proteasome inhibitors could induce apoptosis in a variety of cancer cells. In the present study, we found that, in vincristine-resistant human gastric cancer cell line SGC7901/VCR, proteasome inhibitor MG132 was an effective inducer of apoptosis, and also had the capacity of downregulating the expression of anti-apoptotic Bcl-2 and MDR1 (P-gp), by which MG132 resensitized tumor cells to the apoptosis induced by anticancer drugs. Data presented by drug sensitivity assay further demonstrated that MG132 could reverse the resistant phenotype of gastric cancer cells effectively through both enhancing drug-induced apoptosis and inhibiting P-gp. The further study of the effectiveness and safety of proteasome inhibitor in vivo may be helpful for developing a new possible strategy to treat gastric cancer MDR.

Identifying an effective therapeutic target is pivotal in the treatment of gastric cancer. In this study, we investigated the expression of p75 neurotrophin receptor (p75NTR) in gastric cancer and the impact of its alteration on tumor growth. p75NTR expression was absent or significantly decreased in 212 cases of gastric cancers compared with the normal gastric mucosa (P < .05). Moreover, p75NTR expression was also lost or significantly decreased in various human gastric cancer cell lines. p75NTR inhibited in vitro growth activities and caused dramatic attenuation of tumor growth in animal models by induction of cell cycle arrest. Upregulation of p75NTR led to downregulation of cyclin A, cyclin D1, cyclin E, cyclin-dependent kinase 2, p-Rb, and PCNA, but to upregulation of Rb and p27 expressions. Conversely, downregulating p75NTR with specific siRNA yielded inverse results. The rescue of tumor cells from cell cycle progression by a death domain-deleted dominant-negative antagonist of p75NTR (Δp75NTR) showed that the death domain transduced antiproliferative activity in a ligandindependent manner and further demonstrated the inhibitive effect of p75NTR on growth in gastric cancer. Therefore, we provided evidence that p75NTR was a potential tumor suppressor and may be used as a therapeutic target for gastric cancer.

The p75 neurotrophin receptor (p75NTR) is a focus for study at present. However, its function in gastric cancer was not elucidated. Here, we investigated its relation with metastasis of gastric cancer. By immunohistochemistry, we found that the positive rate of p75NTR expression in metastatic gastric cancer was 15.09% (16 of 106), which was lower compared with nonmetastatic gastric cancer (64.15%; 68 of 106). The average staining score in nonmetastatic gastric cancer was significantly higher than in metastatic gastric cancer (1.21 ± 0.35 versus 0.23 ± 0.18; P < 0.01). p75NTR protein level was also lowly expressed in the highly liver-metastatic gastric cancer cell line XGC9811-L compared with other gastric cancer cell lines by Western blotting. It could also significantly inhibit the in vitro adhesive, invasive, and migratory and in vivo metastatic abilities of gastric cancer cell lines SGC7901 and MKN45 by reducing urokinase-type plasminogen activator (uPA) and matrix metalloproteinase (MMP)-9 proteins and by increasing tissue inhibitor of matrix metalloproteinase (TIMP)-1 protein. Further studies showed that p75NTR could suppress the nuclear factor-κB (NF-κB) signal. SN50, a specific inhibitor of NF-κB, which could inhibit in vitro invasive and migratory abilities of gastric cancer cells, reduced expression of uPA and MMP9 proteins and increased expression of TIMP1 protein. Taken together, p75NTR had the function of inhibiting the invasive and metastatic abilities of gastric cancer cells, which was mediated, at least partially, by down-regulation of uPA and MMP9 proteins and up-regulation of TIMP1 protein via the NF-κB signal transduction pathway. Our studies suggested that p75NTR may be used as a new potential therapeutic target in metastatic gastric cancer. (Mol Cancer Res 2007;5(5):423–30)

Peritoneal dissemination in gastric cancer is the most frequent cause of the noncurative resection and recurrence after curative resection. We, therefore, evaluated the feasibility of a peptide, which was obtained by screening a random phage display library, in the treatment of peritoneal metastases of gastric cancer. In this study, a novel cell line, GC9811-P, with a high potential peritoneal metastasis of gastric cancer derived from its parental cell line, GC9811, was established. Using a phage display library, we isolated a specific peptide that selectively bound to GC9811-P cells rather than its parental GC9811cells. The isolated phage-displaying peptide, SMSIASPYIALE (named peptide PIII), was obtained after four rounds of selection, showing a tendency to preferentially bind to GC9811-P cells compared with a panel of other gastric cancer cell lines, and preferentially accumulate in peritoneal metastasis tumor tissue in comparison with control organs, peritoneum, liver, pancreas, spleen, lung, and kidney. Further study showed that synthetic peptide PIII could significantly inhibit adhesive and invasional ability of GC9811-P cells and could effectively block the corresponding phage binding to the GC9811-P cells, whereas, exposure of the cells to various concentrations of peptide PIII showed no obvious cell growth inhibition. Furthermore, a highly reproducible animal experimental model of gastric cancer with peritoneal dissemination was established in nude mice by injecting a suspension of the cell line into the gastric wall of nude mice. Animals intraperitoneally treated with peptide PIII in this model or another animal model of gastric cancer with peritoneal dissemination established using MKN45 cells showed suppressed tumor metastasis to peritoneum and significantly prolonged survival. In conclusion, the selected peptide PIII was a biologically active peptide and could effectively inhibit peritoneal dissemination of gastric cancer.

Anti-calcyclin binding protein (CacyBP) monoclonal antibodies (MAb) were produced using an in vitro immunization method. BALB/c mouse splenocytes were immunized with purified 6 x His-CacyBP fusion protein and fused with myeloma cells using polyethylene glycol (PEG) 4000. By selection using enzyme-linked immunosorbent assay (ELISA), three anti-CacyBP MAbs were obtained. The MAb BD1, whose isotype was IgG1, interacted with the fusion protein. Western blot and immunofluorescence microscopy showed that the MAb BD1 against CacyBP could recognize CacyBP protein derived from human gastric cancer cell lines in both native and denatured forms. This MAb would act as a useful tool for the detection of CacyBP protein in future studies.

10 páginas, 6 figuras, 2 tablas., MC3 is a colorectal cancer (CRC)-specific mAb previously prepared in our laboratory that can detect CRC with high sensitivity and specificity. However, the target antigen for MC3 had not been identified due to technological limitations. In the present study, immunocytochemistry and immunohistochemistry revealed the expression patterns of MC3 antigen (MC3-Ag) in colon cancer cell lines and CRC tissues. Western blotting analysis showed that the MC3 antibody reproducibly recognized two ∼30 kDa proteins in the total cell lysates of human colon carcinoma cell lines SW480 and HT-29. Using a proteomic approach, we identified two MC3 immunoreactive spots as two isoforms of thioredoxin-like 2 (Txl-2) protein. Further paired immunostaining showed that Txl-2 had the same expression profile as probed by the MC3 antibody. Western blotting also showed that both antibodies could detect the same two bands, further verifying that Txl-2 is the antigen of MC3 antibody. Additionally, tissue arrays revealed the expression patterns of Txl-2 in various normal and cancer tissues. Further analysis showed that Txl-2 mRNA was elevated in 18 cases of CRC tissues compared to paracancerous tissues and adjacent normal tissues., This work was supported by grants from National Natural Science Foundation of China (No. 30672399) and National High Technology Research and Development Program of China (No. 2006AA02A253).

Calcyclin-binding protein (CacyBP)/Siah-1 interacting protein (SIP), a component of ubiquitin-mediated proteolysis, could bind the Skp1-Cul1-F box protein complex. Although CacyBP/SIP was implicated in p53-induced β-catenin degradation, its exact function was still unknown. Our previous studies showed that CacyBP/SIP could modulate the multidrug-resistant phenotype of gastric cancer cells and was highly expressed in gastric cancer tissues compared with that in non-cancerous tissues. In this study, CacyBP/SIP protein expression profile in a broad range of human normal tissues and carcinomas was analyzed by immunohistochemistry staining with anti-CacyBP/SIP monoclonal antibody first produced in our laboratory. CacyBP/SIP was generally localized in the cytoplasm/nucleus. Positive staining of CacyBP/SIP was found in brain, heart, lymph node, and esophagus. Weak staining was shown in the rectum and kidney. No CacyBP/SIP was detected in other normal tissues. However, CacyBP/SIP was ubiquitously detected in all kinds of tumor tissues and was highly expressed in nasopharyngeal carcinoma, osteogenic sarcoma, and pancreatic cancer. To our knowledge, this is the first study on the CacyBP/SIP expression pattern in a broad range of human normal and tumor tissues. The data presented should serve as a useful reference for other investigators in future studies of CacyBP/SIP functions. Hopefully, this knowledge will lead to discovery of more roles of CacyBP/SIP in tumorigenesis. (J Histochem Cytochem 56:765–772, 2008)

To explore the proteins regulated by cyclooxygenase-2 (COX-2) in gastric cancer, the expression plasmid of COX-2siRNA was constructed and transfected into gastric cancer cell line SGC7901. Then, two-dimensional electrophoresis and the PDQuest software analysis were applied to discover the differentially expressed proteins. The differential protein spots were analyzed by matrix-assisted laser desorption/ionization time of flight mass spectrometry. Fourteen differentially expressed proteins between the two cell lines were identified. 15-Hydroxyprostaglandin dehydrogenase [NAD(+)] (15-PGDH), a key enzyme in prostaglandin degradation, was identified as an upregulated protein in SGC7901 cells transfected with the COX-2siRNA plasmid. To further explore whether the 15-PGDH is regulated by COX-2, western blotting and immunocytochemical assay were performed to detect the expression of 15-PGDH in different cell lines with different expression level of COX-2. The results showed that the expression of 15-PGDH was upregulated (128.57%) as COX-2 was suppressed by small interfering RNA and downregulated (51.72%) as COX-2 was enhanced by COX-2 cDNA transfection in gastric cancer cells. In tissue specimens with gastric cancer, there was a decreased expression of 15-PGDH and an increased expression of COX-2 simultaneously. A significantly negative correlation of 15-PGDH expression was found to COX-2 level, tumor differentiation, tumor, lymph node, metastasis (TNM) staging and lymph node metastasis of gastric cancer. All the results suggest that 15-PGDH is downregulated by COX-2 in human gastric cancer and may contribute to the carcinogenesis and development of human gastric cancer in combination with COX-2.

We report the isolation and functional characterization of the gene encoding MGr1-Ag, a multidrug-resistance-associated protein. A lambdagt11 cDNA library derived from colorectal carcinoma SW480 cells was screened with monoclonal antibody MGr1. DNA homology analysis of 22 positive clones (designated R1-R22) suggested human 37-kDa laminin receptor precursor (37LRP, R7/R9/R15/R16/R19/R20) and a novel gene (R22) as candidate genes encoding MGr1-Ag. Western blot analysis showed that anti-R20 serum reacted with a unique protein band that was consistent with MGr1-Ag, while anti-R22 serum could not react with MGr1-Ag. The coding gene for MGr1-Ag was amplified using reverse transcription-PCR. Sequence analysis revealed that the MGr1-Ag and 37LRP genes shared the same coding sequence. An in vitro drug sensitivity assay indicated that down-regulation of 37LRP by an antisense technique could significantly enhance the cytotoxicity of anticancer drugs to gastric cancer cells. Thus we draw the conclusion that MGr1-Ag is identical to 37LRP.

To study the mechanisms of multidrug resistance (MDR) mediated by human 67 000 laminin receptor (LR) with a relative molecular mas of 67 000 in gastric cancer cells.Antisense RNA expression vector corresponding to LR precursor (LRP) was constructed by DNA recombinant technique, and transferred into gastric cancer MDR cells SGC7901/VCR with Lipofect AMINE. Western blot was employed to determine the LR expression level in gastric cancer cells. The sensitivity of gastric cancer cells to chemotherapeutic drugs was evaluated with MTT assay. Flow cytometry was used to analyze the cell cycle and to assess the mean fluorescence intensity of intracellular adriamycin in gastric cancer cells.Western blotting analysis demonstrated a decreased expression level of LR in SGC7901/VCR cells transfected with LRP antisense RNA expression vector. In comparison with the gastric cancer cells with out transfection or transfected with invalid vector, LR down-regulated transfectants (SGC7901/VCR-anLRP) showed higher sensitivity to vincristine, adriamycin, 5-fluodrouracil and cisplatin, and increased accumulation and retention of adriamycin. Cell cycle analysis suggested G1 block and spontaneous apoptosis of SGC7901/VCR-anLRP cells.LR might take part in mediation of MDR in gastric cancer cells through interfering with drug accumulation and cell apoptosis.