Immunocyte membrane-derived biomimetic nano-drug delivery system: a pioneering platform for tumour immunotherapy.

Tumor immunotherapy characterized by its high specificity and minimal side effects has achieved revolutionary progress in the field of cancer treatment. However, the complex mechanisms of tumor immune microenvironment (TIME) and the individual variability of patients' immune system still present significant challenges to its clinical application. Immunocyte membrane-coated nanocarrier systems, as an innovative biomimetic drug delivery platform, exhibit remarkable advantages in tumor immunotherapy due to their high targeting capability, good biocompatibility and low immunogenicity. In this review we summarize the latest research advances in biomimetic delivery systems based on immune cells for tumor immunotherapy. We outline the existing methods of tumor immunotherapy including immune checkpoint therapy, adoptive cell transfer therapy and cancer vaccines etc. with a focus on the application of various immunocyte membranes in tumor immunotherapy and their prospects and challenges in drug delivery and immune modulation. We look forward to further exploring the application of biomimetic delivery systems based on immunocyte membrane-coated nanoparticles, aiming to provide a new framework for the clinical treatment of tumor immunity.

[Effect of Naotaifang on microglial polarization and glial scar following cerebral ischemia reperfusion injury].

This study aims to investigate the effect of Naotaifang(NTF) on the proteins associated with microglial polarization and glial scar in the rat model of cerebral ischemia reperfusion injury(CIRI). The CIRI model was established by middle cerebral artery occlusion/reperfusion. The 48 successfully modeled rats were randomized into model 7 d, model 14 d, NTF 7 d, and NTF 14 d groups(n=12). In addition, 12 SD rats were selected as the sham group. The NTF group was administrated with NTF suspension at 27 g·kg~(-1)·d~(-1) by gavage, and the sham, model 7 d, and model 14 d groups were administrated with the same volume of normal saline every day by gavage for 7 and 14 days, respectively. After the intervention, Longa score was evaluated. The infarct volume was measured by 2,3,5-triphenyl-2H-tetrazolium chloride(TTC) staining. Morris water maze and open field tests were carried out to evaluate the spatial learning, memory, cognitive function, and anxiety degree of rats. Hematoxylin-eosin(HE) staining was employed to observe the morphological structure and damage of the brain tissue. The immunofluorescence assay was employed to measure the expression of glial fibrillary acidic protein(GFAP) and glial scar. Western blot was employed to determine the protein levels of GFAP, neurocan, phosphacan, CD206, arginase-1(Arg-1), interleukin(IL)-1ß, IL-6, and IL-4. Compared with the sham, model 7 d and model 14 d groups showed cerebral infarction of different degrees, severe pathological injury of cerebral cortex and hippocampus, neurological impairment, reduced spatial learning and memory, cognitive dysfunction, severe anxiety, astrocyte hyperplasia, thickening penumbra glial scar, and up-regulated protein levels of IL-1ß, IL-6, GFAP, neurocan, phosphacan, CD206, and Arg-1(P<0.01). Compared with the model group, NTF 7 d and NTF 14 d groups improved spatial learning, memory, and cognitive function, reduced anxiety, improved nerve function, reduced cerebral infarction volume, reduced astrocyte hyperplasia, thinned penumbra glial scar, down-regulated the protein levels of GFAP, neurocan, phosphacan, IL-6, and IL-1ß, and up-regulated the protein levels of IL-4, CD206, and Arg-1(P<0.05 or P<0.01). NTF exerts a neuroprotective effect on CIRI by inducing the M2 polarization of microglia, inhibiting inflammatory response, and reducing the formation of glial scar.

Screening for upper gastrointestinal cancers with magnetically controlled capsule gastroscopy: a feasibility study.

BACKGROUND: The medical consortium is an intensive and disease-specific association that integrates tertiary public hospitals and medical examination centers in China. We aimed to evaluate the feasibility of the medical consortium for screening upper gastrointestinal (GI) cancers (MCSC) by magnetically controlled capsule gastroscopy (MCCG). METHODS: 6627 asymptomatic subjects underwent MCCG as part of health check-ups in the MCSC between March and November 2018. Relevant clinical data were collected and analyzed. RESULTS: The MCSC detected 32 patients with upper GI cancer (0.48 %) confirmed by pathology. The detection rate of early gastric cancer was 16.67 % (4 /24). Gastric polyps, ulcers, and submucosal tumors were found in 15.54 %, 3.76 %, and 3.17 % of subjects, respectively. The whole GI preparation and operation process were well tolerated. CONCLUSIONS: The MCSC was a feasible model for upper GI cancer screening, especially for asymptomatic subjects. Further prospective studies with better operational quality control are warranted.

Novel detachable stents for the treatment of benign esophageal strictures.

The radial force of esophageal stents may not completely change during extraction and therefore, the procedure of stent removal may cause tissue damage. The present study reports the manufacture of 2 novel detachable stents, which were designed to reduce tissue damage through their capacity to be taken or fall apart prior to removal and evaluated the supporting properties of these stents and the extent of local mucosal injury during their removal. The stents were manufactured by braiding, heat-setting, coating and connecting. The properties of the stents were evaluated by determining the following parameters: Expansion point, softening point, stent flexibility, radial compression ratio and radial force. A total of 18 rabbits with induced esophageal stricture were randomly assigned to 3 groups as follows: Detachable stent (DS) group, biodegradable stent (BS) group and control group. The stricture rate, complications, survival, degradation and stent removal were observed over 8 weeks. The stents of the DS and BS groups provided a similar supporting effect. The stricture rate, incidence of complications and survival were also similar between the 2 groups, while significant differences were noted between the DS and control groups and between the BS and control groups. In the BS group, the stents were degraded and moved to the stomach within 7 weeks (2 in 6 weeks and 3 in 7 weeks). The debris was extracted using biopsy forceps. In the DS group, all stents were easy to remove and 2 cases exhibited minor hemorrhage. In conclusion, the 2 types of novel detachable stent provided an equally efficient supporting effect in vitro and in vivo and may reduce the incidence of secondary injury during stent removal.

Accuracy of Magnetically Controlled Capsule Endoscopy, Compared With Conventional Gastroscopy, in Detection of Gastric Diseases.

BACKGROUND & AIMS: Diseases of the stomach, including gastric cancer and peptic ulcer, are the most common digestive diseases. It is impossible to visualize the entire stomach with the passive capsule currently used in practice because of the large size of the gastric cavity. A magnetically controlled capsule endoscopy (MCE) system has been designed to explore the stomach. We performed a prospective study to compare the accuracy of detection of gastric focal lesions by MCE vs conventional gastroscopy (the standard method). METHODS: We performed a multicenter blinded study comparing MCE with conventional gastroscopy in 350 patients (mean age, 46.6 y), with upper abdominal complaints scheduled to undergo gastroscopy at a tertiary center in China from August 2014 through December 2014. All patients underwent MCE, followed by conventional gastroscopy 2 hours later, without sedation. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of detection of gastric focal lesions by MCE, using gastroscopy as the standard. RESULTS: MCE detected gastric focal lesions in the whole stomach with 90.4% sensitivity (95% confidence interval [CI], 84.7%-96.1%), 94.7% specificity (95% CI, 91.9%-97.5%), a positive predictive value of 87.9% (95% CI, 81.7%-94.0%), a negative predictive value of 95.9% (95% CI, 93.4%-98.4%), and 93.4% accuracy (95% CI, 90.83%-96.02%). MCE detected focal lesions in the upper stomach (cardia, fundus, and body) with 90.2% sensitivity (95% CI, 82.0%-98.4%) and 96.7% specificity (95% CI, 94.4%-98.9%). MCE detected focal lesions in the lower stomach (angulus, antrum, and pylorus) with 90.6% sensitivity (95% CI, 82.7%-98.4%) and 97.9% specificity (95% CI, 96.1%-99.7%). MCE detected 1 advanced gastric carcinoma, 2 malignant lymphomas, and 1 early stage gastric tumor. MCE did not miss any lesions of significance (including tumors or large ulcers). Among the 350 patients, 5 reported 9 adverse events (1.4%) and 335 preferred MCE over gastroscopy (95.7%). CONCLUSIONS: MCE detects focal lesions in the upper and lower stomach with comparable accuracy with conventional gastroscopy. MCE is preferred by almost all patients, compared with gastroscopy, and can be used to screen gastric diseases without sedation. Clinicaltrials.gov number: NCT02219529.

Newly designed "pieced" stent in a rabbit model of benign esophageal stricture.

AIM: To investigate a newly designed stent and its dilatation effect in a rabbit model of benign esophageal stricture. METHODS: Thirty-four New Zealand white rabbits underwent a corrosive injury in the middle esophagus for esophageal stricture formation. Thirty rabbits with a successful formation of esophageal strictures were randomly allocated into two groups. The control group (n = 15) was implanted with a conventional stent, and the study group (n = 15) was implanted with a detachable "pieced" stent. The study stent (30 mm in length, 10 mm in diameter) was composed of three covered metallic pieces connected by surgical suture lines. The stent was collapsed by pulling the suture lines out of the mesh. Two weeks after stricture formation, endoscopic placement of a conventional stent or the new stent was performed. Endoscopic extraction was carried out four weeks later. The extraction rate, ease of extraction, migration, complications, and survival were evaluated. RESULTS: Stent migration occurred in 3/15 (20%) animals in the control group and 2/15 (13%) animals in the study group; the difference between the two groups was not statistically significant. At the end of four weeks, the remaining stents were successfully extracted with the endoscope in 100% (11/11) of the animals in the study group, and 60% (6/10) of the animals in the control group; this difference was statistically significant (P < 0.05). There was no difference in the mean number of follow-up days between the control and study groups (25.33 vs 25.85). Minor bleeding was reported in five cases in the study group and four in the control group. There were no severe complications directly associated with stent implantation or extraction in either of the two groups. CONCLUSION: In this experimental protocol of benign esophageal strictures, the novel "pieced" stent demonstrated a superior removal rate with a similar migration rate compared to a conventional stent.

MiR-454 prompts cell proliferation of human colorectal cancer cells by repressing CYLD expression.

Previous studies have shown that miR-454 plays an important role in a variety of biological processes in various human cancer cells. However, the underlying mechanisms of this microRNA in colorectal cancer (CRC) cells remain largely unknown. In the present study, we investigated the miR-454 role in CRC cell proliferation. We found that miR-454 expression is markedly upregulated in CRC tissues and CRC cells compared with the matched tumor adjacent tissues and the FHC normal colonic cell line. Ectopic expression of miR-454 promoted the proliferation and anchorage-independent growth of CRC cells, whereas inhibition of miR-454 reduced this effect. Bioinformatics analysis further revealed cylindromatosis (CYLD), a putative tumor suppressor as a potential target of miR-454. Data from luciferase reporter assays showed that miR-454 directly binds to the 3'-untranslated region (3'-UTR) of CYLD mRNA and repressed expression at both transcriptional and translational levels. In functional assays, CYLD-silenced in miR-454-in-transfected SW480 cells have positive effect to promote cell proliferation, suggesting that direct CYLD downregulation is required for miR-454-induced CRC cell proliferation. In sum, our data provide compelling evidence that miR-454 functions as an onco-miRNA, playing a crucial role in the promoting cell proliferation in CRC, and its oncogenic effect is mediated chiefly through direct suppression of CYLD expression.

Endoscopic submucosal dissection vs endoscopic mucosal resection for colorectal tumors: a meta-analysis.

AIM: To compare the efficacy and safety of endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) for the treatment of colorectal tumors. METHODS: Databases, such as PubMed, EMBASE, Cochrane Library and Science Citation Index updated to 2013 were searched to include eligible articles. In the meta-analysis, the main outcome measurements were the en bloc resection rate, the histological resection rate and the local recurrence rate. Meanwhile, we also compared the operation time and the incidence of procedure-related complications. RESULTS: Six trials were identified and a total of 1642 lesions were included. The en bloc resection rate was higher and the local recurrence rate was lower in the ESD group compared with the EMR group (OR = 7.94; 95%CI: 3.96-15.91; OR = 0.09; 95%CI: 0.04-0.19). There was no significant difference in histological resection rate(OR = 1.65; 95%CI: 0.29-9.30) and procedure-related complication rate between the two groups (OR = 1.59; 95%CI: 0.92-2.73). The meta-analysis also showed that ESD was more time consuming than EMR. CONCLUSION: Compared with EMR, ESD results in higher en bloc resection rate and lower local recurrence rate for the treatment of colorectal tumors, without increasing the procedure-related complications.

Combining bevacizumab and panitumumab with irinotecan, 5-fluorouracil, and leucovorin (FOLFIRI) as second-line treatment in patients with metastatic colorectal cancer.

Bevacizumab and panitumumab are human monoclonal antibodies with different targeting antigens, vascular endothelial growth factor, and epidermal growth factor receptor. This study examined the efficacy and safety of combining bevacizumab and panitumumab plus fluorouracil, leucovorin, and irinotecan (FOLFIRI) as the second-line therapy for patients with metastatic colorectal cancer (mCRC). Patients with mCRC, and previously failed with oxaliplatin-based chemotherapy, were given bevacizumab (3 mg/kg) and panitumumab (3 mg/kg) plus FOLFIRI every other week. From September 2008 to July 2012, 173 patients were included in the study. The response rate was 42.3 %, and the disease-controlled rate was 65.7 %. The median progression-free survival was 6.5 months, and the median overall survival was 15.4 months. Various adverse events (AE) including those known toxicities associated with antibody therapy were recorded. The overall AE rate was 64.5 % for grade 3-4. The treatment of combining bevacizumab and panitumumab plus FOLFIRI is effective and safe as a second-line therapy for patients with mCRC.

Obesity and the risk of cholangiocarcinoma: a meta-analysis.

A number of studies have shown that obesity is implicated in the susceptibility to several cancers. However, the association between obesity and cholangiocarcinoma remains unclear. This meta-analysis aimed to quantitatively assess the association between overweight or obesity and the incidence of cholangiocarcinoma. A literature search was performed for cohort and case-control studies published from 1996 to 2013 using PubMed, Cochrane, and EMBASE databases. Studies were included if they reported odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) of cholangiocarcinoma with respect to obesity or overweight. Normal weight, overweight, and obesity were defined when the body mass index (BMI) was 18.5-24.9, 25-29.9, and ≥ 30 kg/m(2), respectively. Excess body weight was defined as BMI ≥ 25 kg/m(2). Ten studies met the inclusion criteria, which included five cohort and five case-control studies. Compared with normal weight, being overweight (pooled OR 1.30, 95 % CI 1.13-1.49), obesity (pooled OR 1.52, 95 % CI 1.13-1.89), and excess body weight (pooled OR 1.37, 95 %CI 1.22-1.55) were significantly associated with cholangiocarcinoma. The funnel plot revealed no evidence for publication bias. Obesity is associated with the increased risk of cholangiocarcinoma, which needs to be confirmed by long-term cohort studies.

Endoscopic submucosal dissection versus endoscopic mucosal resection for the treatment of early esophageal carcinoma: a meta-analysis.

Endoscopic submucosal dissection (ESD) was originally developed for en bloc resection of large, flat gastrointestinal lesions. Compared with endoscopic mucosal resection (EMR), ESD is considered to be more time consuming and have more complications for treatment of early esophageal carcinoma, such as bleeding, stenosis and perforation. The objective of this study was to compare the efficacy and safety of ESD and EMR for such lesions. We searched databases, such as PubMed, EMBASE, Cochrane Library and Science Citation Index updated to 2013 for related trials. In the meta-analysis, the main outcome measurements were the en bloc resection rate, the histologically resection rate and the local recurrence rate. We also compared the operation time and the incidences of procedure-related complications. Five trials were identified, and a total of 710 patients and 795 lesions were included. The en bloc and histologically complete resection rates were higher in the ESD group compared with the EMR group (odds ratio (OR) 27.3; 95% CI, 11.5-64.8; OR 18.4; 95% CI, 8.82-38.59). The local recurrence rate was lower in the ESD group (OR 0.13, 95 % CI 0.04-0.43). The meta-analysis also showed ESD was more time consuming, but did not increase the complication rate (P=0.76). The results implied that compared with EMR, ESD showed better en bloc and histologically resection rates, and lower local recurrence, without increasing the incidence of procedure-related complications in the treatment of early esophageal carcinoma.

Chronic hepatitis B virus infection and risk of pancreatic cancer: a meta-analysis.

OBJECTIVES: A number of studies have shown that chronic hepatitis B virus infection is implicated in susceptibility to pancreatic cancer. However, the results are still controversial. This meta-analysis aimed to quantitatively assess the relationship between chronic hepatitis B virus infection and incidence of pancreatic cancer of cohort and case-control studies. METHODS: A literature search was performed for entries from 1990 to 2012 using PUBMED and EMBASE. Studies were included if they reported odds ratios (ORs) and corresponding 95% CIs of pancreatic cancer with respect to the infection of hepatitis B virus. RESULTS: Eight studies met the inclusion criteria, which included five case-control studies and three cohort studies. Compared with individuals who have not infection of hepatitis B virus, the pooled OR of pancreatic cancer was 1.403 (95%CI: 1.139-1.729, P=0.001) for patients with hepatitis B virus infection. Sub-group analysis by study design showed that the summary OR was 1.43 (95%CI: 1.06-1.94, P=0.021) when pooling case-control studies and 1.31 (95%CI: 1.00- 1.72, P=0.05) when pooling cohort studies. CONCLUSION: Findings from this meta-analysis suggest that chronic hepatitis B virus infection may increase the risk of pancreatic cancer. This relationship needs to be confirmed by further follow-up studies.

The retrovirus-mediated antisense human telomerase RNA (hTR) gene limits the growth of hepatocellular carcinoma growth in cell culture and animals.

AIM: To investigate the inhibitory effect of retrovirus-mediated antisense human telomerase RNA (hTR) gene therapy on hepatocelluar carcinoma. METHODS: We first constructed the sense and antisense hTR vectors and then transfected these into HepG2 cells. Telomerase activity, cell growth curves, proliferating cell nuclear antigen expression (PCNA), cell cycle distribution, and cell apoptosis were detected by the means of telemere repeat amplification protocol (TRAP), MTT assay, immunofluorescence, flow cytometric analysis, and transferase-mediated nick end labeling (TUNEL), respectively. In order to further confirm the therapeutic effect of this gene therapy, we developed an experimental line of HepG2 tumor-bearing nude mice by and directly injected these with retrovirus expressing the antisense hTR gene. Tumor growth was determined by tumor volume, and cell apoptosis was analyzed by TUNEL. RESULTS: The antisense hTR gene was shown to be successfully integrated into the target cells' genome. HepG2 cells transfected with the antisense hTR gene showed down-regulated telomerase activity, inhibited cell growth, decreased PCNA expression, and increased apoptotic rate. Moreover, flow cytometry revealed a decrease of cells in the S phase with cell cycle arrest at the G2/M phase. In the antisense hTR-treated group, tumor growth was significantly reduced and showed an increase of apoptotic cells. CONCLUSION: The results indicate that the specific inhibitor of the hTR template is likely to be a very efficient tool for hepatocellular carcinoma research and may possess potential therapeutic significance in the future clinical practice.

Effects of endogenous nitric oxide induced by 5-fluorouracil and L-Arg on liver carcinoma in nude mice.

AIM: To study the effects of endogeous nitric oxide induced by 5-fluorouracil (5-FU) and L-arginine (L-Arg) on the human liver carcinoma model in nude mice. METHODS: The human liver carcinoma model in nude mice was established with BEL-7402 cells and normal saline (NS), 5-FU and 5-FU + L-Arg injected intraperitoneally. The tumor size was measured. The necrotic degree and range were observed under microscope. The apoptosis of cancer cell was detected by turmina deoxynucleotidyl transferanse mediated dUTP nick end labeling (TUNEL) method. Immunohistochemical method was performed to determine the expression of iNOS, P16, BAX. The chemical colorimetry was used to test the activity and nitrate reductase method was adopted to test the concentration of nitric oxide (NO) in the tumor tissue. The BI2000 pathological image analyzer was used to analyze the result of immunohistochemistry. RESULTS: 5-FU combined with L-Arg could inhibit the tumor growth apparently. In NS, 5-FU and 5-FU+L-Arg groups, the changes of tumor volumes were 257.978 +/- 59.0, 172.232 +/- 66.0 and 91.523 +/- 26.7 mm(3), respectively (P < 0.05 5-FU vs 5-FU + L-Arg group; P < 0.05 NS vs 5-FU + L-Arg group; P < 0.05, NS vs 5-FU group). The necrotic range and apoptosis index were significantly increased after the drug injection. The necrotic range was biggest in 5-FU + L-Arg group (c2 = 15.963, P < 0.05). The apoptosis indexes were as follows: NS, 17.4% +/- 6.19%; 5-FU, 31.3% +/- 12.3%; and 5-FU + L-Arg, 46% +/- 15.24% (P < 0.05, 5-FU vs 5-FU + L-Arg; P < 0.05, NS vs 5-FU + L-Arg; P < 0.05, NS vs 5-FU). The expression and activity of iNOS were increased in the tumor tissue. The concentration of NO was also increased. F of optical density of iNOS, iNOS activity and NO concentration are 31.693, 21.949, and 33.909, respectively, P < 0.05. The concentration of NO was related to the expression of P16 and BAX. The correlation coefficient was 0.764 and 0.554. CONCLUSION: 5-FU combined with L-Arg can inhibit the growth of tumor in nude mice. The effect may be related to inducing the synthesis and increasing the activity of iNOS. The production of NO is increased, and it can enhance the expression of apoptosis-related gene and antioncogene.

Functional polymorphisms in the cyclooxygenase 2 (COX-2) gene and risk of breast cancer in a Chinese population.

Cyclooxygenase (COX), the rate-limiting enzyme in prostaglandins (PG) synthesis, exists in at least two isoforms, COX-1 and COX-2. COX-2 plays an important role in carcinogenesis, and overexpression may increase proliferation, inhibit apoptosis, and enhance the invasiveness of breast cancer cells. Polymorphisms in the regulatory regions of the COX-2 gene may influence function and/or expression and contribute to interindividual variability in susceptibility to cancer. In this study three variants (-1195G/A and -765G/C in the promoter and 8473C/T in 3'UTR) of COX-2 were examined for correlation with breast cancer risk. A case-control study of 615 histologically confirmed breast cancer patients and 643 cancer-free controls frequency-matched for age were selected. Logistic regression analyses revealed that no overall significant associations were detected in the single-locus analysis between three polymorphisms of COX-2 and the risk of breast cancer. However, a significantly increased risk of breast cancer was associated with the combined genotypes containing "more than 3 variant alleles"' (adjusted OR = 1.37, 95% CI 1.01-1.84) compared with the combined genotypes with "0-3 variant alleles." Haplotype analyses showed that haplotypes A-1195G-765T8473 and A-1195C-765T8473 were significantly associated with breast cancer risk (OR = 1.20, 95% CI 1.01-1.43 for A-1195G-765T8473; OR = 9.16, 95% CI 1.14-73.51 for A-1195C-765T8473) compared with the most common haplotype, G-1195G-765T8473. These findings indicate that these three variants in the regulatory regions of COX-2 may contribute to the etiology of breast cancer.

Effect of matrine on the expression of substance P receptor and inflammatory cytokines production in human skin keratinocytes and fibroblasts.

Matrine is a kind of alkaloid found in certain Sophora plants, which has been extensively used in China for the treatment of viral hepatitis, cancer, cardiac diseases and skin diseases (such as atopic dermatitis and eczema). It also has been confirmed that substance P (SP) and its receptor (neurokinin-1 receptor, NK-1R) are involved in the pathogenesis of inflammatory skin disorders. So the present study was designed to investigate the effect of matrine on the expression of NK-1R and cytokines production induced by SP in HaCaT cells (a human epidermal keratinocyte cell line) and dermal fibroblasts. In addition, cell viability was also evaluated. The results showed that matrine inhibited the expression of NK-1R in HaCaT cells and fibroblasts. SP induced the production of interleukin (IL)-1beta, IL-8, interferon (IFN)-gamma, and monocyte chemotactic protein (MCP)-1 in both cell types. Matrine 5-100 microg/mL had little effect on cell viability. It inhibited SP-induced IL-1beta, IL-8 and MCP-1 production in HaCaT cells and fibroblasts, while it increased the production of IFN-gamma in HaCaT cells. Both SP and matrine had no effect on the secretion of IL-6. These findings suggest that matrine may have potential treatment function on SP related cutaneous inflammation by inhibition of the expression of substance P receptor and regulation of the production of inflammatory cytokines.

The association of polymorphisms of CDT1 and GMNN gene with the risk of breast cancer in Chinese women: a case-control analysis.

OBJECTIVE: To investigate the association of polymorphisms of CDT1 and GMNN gene, two important genes participating in DNA replication, with the risk of sporadic breast cancer. METHODS: Using polymerase chain reaction-restriction fragment length polymorphism (PCR - RFLP) and the primer-introduced restriction analysis (PIRA)-PCR assay to genotype the CDT1 838G/A and GMNN 387C/A polymorphisms in a case-control study of 427 breast cancer cases and 477 cancer-free controls in a Chinese population. RESULTS: No significant association of the CDT1 838G/A and GMNN 387C/A polymorphisms with the risk of breast cancer was found (adjusted OR:1.16, 95% CI:0.88-1.54 for CDT1 GA+AA genotypes and adjusted OR:0.90, 95% CI:0.67-1.21 for GMNN CA+AA genotypes). However, in the stratified analyses, a significant association of CDT1 GA+AA genotypes with breast cancer risk among subjects with family history of cancer was found (adjusted OR:2.21, 95% CI:1.20-4.09). CONCLUSION: These findings suggest that the CDT1 838G/A and GMNN 387C/A polymorphisms may not play a major role in the etiology of breast cancer, but CDT1 variant may have a potential role only in genetically susceptible women.

Influence of antitumor drugs on the expression of Fas system in SW480 colon cancer cells.

AIMS: To observe the influence of popular antitumor drugs [5-fluorouracil (5-FU), mitomycin (MMC), cisplatin (CP) and all-trans retinoic acid (ATRA)] on the expression of Fas system in SW480 colon cancer cells. METHODS: The expressions of Fas/FasL protein and mRNA in colon cancer line SW480 cells before and after the treatment of the antitumor drugs (5-FU, MMC, CP and ATRA) were detected by immunocytochemistry, flow cytometry and reverse-transcriptase polymerase chain reaction. Coculture assays of colon cancer cells and Jurkat cells (Fas-sensitive cells) were performed to observe the counterattack of colon cancer cells to lymphocytes. Apoptosis of Jurkat cells were detected by flow cytometry and fluorescence microscopy. RESULTS: SW480 expressed high FasL and low Fas without drug treatments. When treated with 5-FU, Fas expression rates in SW480 increased, but FasL remained unchanged. Both Fas and FasL increased significantly when treated with MMC and CP. Most importantly, ATRA could induce SW480 cells to differentiate, increase the expression of Fas and decrease the expression of FasL. The coculture of SW480 cells and Jurkat cells confirmed the function of FasL in the SW480 cells. CONCLUSION: Certain antitumor drugs can change the expression of the Fas system in SW480 cells in different ways. In vitro, MMC and CP can increase the sensitivity of colon cancer cells to apoptosis signals, but they possibly facilitate immune escape of tumor cells. 5-FU results in immune escape of colon cancer cells. ATRA can down-regulate the possibility of counterattack of colon cancer cells.

Mechanism of counterattack of colorectal cancer cell by Fas/Fas ligand system.

AIM: To determine the role of Fas/Fas ligand (FasL) in the immune escape of colon cancer cells. METHODS: Immunohistochemistry was used to observe the expression of Fas and FasL in the tissues of colon cancer patients. In situ hybridization was used to detect the localization of FasL mRNA expression in cancer tissues. Terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assay and CD45 staining were performed to detect the apoptosis of tumor-infiltrating lymphocytes (TILs). Co-culture assays of colon cancer cells (SW480) and Jurkat cells (Fas-sensitive cells) were performed to observe the counterattack of colon cancer cells to lymphocytes. RESULTS: Of 53 cases of colon carcinomas, 23 cases (43.4%) expressed Fas which was significantly lower as compared to the normal colonic mucosa (73.3%, P<0.01), and 45 cases (84.9%) of colon carcinomas expressed FasL, whereas only two cases (3.75%) in normal mucosa expressed FasL. FasL expression in the colon cancer cells was found to be associated with increased cell death of TILs. The apoptotic rate of TIL in the FasL-positive staining regions of tumor cells was significantly higher than that in the FasL-negative staining region (54.84+/-2.79% vs 25.73+/-1.98%, P<0.01). The co-culture of SW480 cells and Jurkat cells confirmed the function of FasL on the SW480 cells. The apoptotic rates of Jurkat cells were found to be related with the amount of SW480 cells. CONCLUSION: Colon cancer cells can escape the immune surveillance and killing via decreasing Fas expression, and can counterattack the immune system via increasing FasL expression. Fas/FasL can serve as potential targets for effective antitumor therapy.