Increasing glycolysis by deletion of kcs1 and arg82 improved S-adenosyl-L-methionine production in Saccharomyces cerevisiae.

Reprogramming glycolysis for directing glycolytic metabolites to a specific metabolic pathway is expected to be useful for increasing microbial production of certain metabolites, such as amino acids, lipids or considerable secondary metabolites. In this report, a strategy of increasing glycolysis by altering the metabolism of inositol pyrophosphates (IPs) for improving the production of S-adenosyl-L-methionine (SAM) for diverse pharmaceutical applications in yeast is presented. The genes associated with the metabolism of IPs, arg82, ipk1 and kcs1, were deleted, respectively, in the yeast strain Saccharomyces cerevisiae CGMCC 2842. It was observed that the deletions of kcs1 and arg82 increased SAM by 83.3 % and 31.8 %, respectively, compared to that of the control. In addition to the improved transcription levels of various glycolytic genes and activities of the relative enzymes, the levels of glycolytic intermediates and ATP were also enhanced. To further confirm the feasibility, the kcs1 was deleted in the high SAM-producing strain Ymls1ΔGAPmK which was deleted malate synthase gene mls1 and co-expressed the Acetyl-CoA synthase gene acs2 and the SAM synthase gene metK1 from Leishmania infantum, to obtain the recombinant strain Ymls1Δkcs1ΔGAPmK. The level of SAM in Ymls1Δkcs1ΔGAPmK reached 2.89 g L-1 in a 250-mL flask and 8.86 g L-1 in a 10-L fermentation tank, increasing 30.2 % and 46.2 %, respectively, compared to those levels in Ymls1ΔGAPmK. The strategy of increasing glycolysis by deletion of kcs1 and arg82 improved SAM production in yeast.

Glioma SOX2 expression decreased after adjuvant therapy.

BACKGROUND: SOX2 is regarded as an important marker in stem cell. The change of SOX2 expression after adjuvant therapy in high grade glioma (HGG) remains unknown so far. Few patients with recurrent glioma have opportunity to undergo operation once again, so the recurrent glioma samples are scarce. This study tries to analyze SOX2 expression in paired primary and recurrent HGG, aims to better understand the transformation law of SOX2 after adjuvant therapy in HGG. METHODS: Twenty-four recurrent HGG patients who undergone a second resection were included. 16 patients received adjuvant therapy, the remaining 8 patients didn't receive any adjuvant therapy at all. The protein expression of SOX2 in paired primary and recurrent HGG was tested by immunohistochemistry. The statistical analysis was conducted by IBM SPSS Statistics 19.0. RESULTS: In primary HGG, SOX2 expression of 3 + , 2 + , 1+ and 0+ were seen in 20 (83.3%), 1 (4.2%), 1 (4.2%) and 2 cases (8.3%), respectively. The expression of SOX2 was decreased in recurrent HGG compared to the paired primary sample (p = 0.001). The decrease of SOX2 was often seen in patients received chemotherapy, radiotherapy or both (p = 0.003). Patients with SOX2 high expression in primary glioma had a longer median PFS than those with SOX2 low expression with marginal statistic significance (12.7 vs. 5.4 months, p = 0.083). For cases with SOX2 high expression in the primary glioma, those had SOX2 low expression after recurrence seemed to have worse prognosis as compared to patients with stable SOX2 high expression (PFS: 10.4 vs. 14.9 months, p = 0.036; OS: 27.0 vs 49.5 months, p = 0.005). CONCLUSIONS: This is the first study comparing the protein expression of SOX2 in recurrent HGG and its paired primary tumor. SOX2 high expression is common in brain HGG, a tendency of decreased SOX2 expression in recurrent gliomas was evidenced. Lower SOX2 expression was seen in those patients who received adjuvant chemotherapy and/or radiotherapy. Patients with low SOX2 expression in primary HGG usually have poorer prognosis, those with SOX2 expression decreased in recurrent HGG had worse outcome.

CLCA1 suppresses colorectal cancer aggressiveness via inhibition of the Wnt/beta-catenin signaling pathway.

BACKGROUND: Chloride channel accessory 1 (CLCA1) belongs to the calcium-sensitive chloride conductance protein family, which is mainly expressed in the colon, small intestine and appendix. This study was conducted to investigate the functions and mechanisms of CLCA1 in colorectal cancer (CRC). METHODS: The CLCA1 protein expression level in CRC patients was evaluated by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and western blotting analysis. Using CRISPR/Cas9 technology, CLCA1-upregulated (CLCA1-ACT) and CLCA1-knockout cells (CLCA1-KO), as well as their respective negative controls (CLCA1-ACT-NC and CLCA1-KO-NC), were constructed from the SW620 cell line. Cell growth and metastatic ability were assessed both in vitro and in vivo. The association of CLCA1 with epithelial-mesenchymal transition (EMT) and other signaling pathways was determined by western blotting assays. RESULTS: The expression level of CLCA1 in CRC tissues was significantly decreased compared with that in adjacent normal tissue (P< 0.05). Meanwhile, the serum concentration of CLCA1 in CRC patients was also significantly lower when compared with that of healthy controls (1.48 ± 1.06 ng/mL vs 1.06 ± 0.73 ng/mL, P = 0.0018). In addition, CLCA1 serum concentration and mRNA expression level in CRC tissues were inversely correlated with CRC metastasis and tumor stage. Upregulated CLCA1 suppressed CRC growth and metastasis in vitro and in vivo, whereas inhibition of CLCA1 led to the opposite results. Increased expression levels of CLCA1 could repress Wnt signaling and the EMT process in CRC cells. CONCLUSIONS: Our findings suggest that increased expression levels of CLCA1 can suppress CRC aggressiveness. CLCA1 functions as a tumor suppressor possibly via inhibition of the Wnt/beta-catenin signaling pathway and the EMT process.

microRNA-1827 represses MDM2 to positively regulate tumor suppressor p53 and suppress tumorigenesis.

The tumor suppressor p53 plays a central role in tumor prevention. The E3 ubiquitin ligase MDM2 is the most critical negative regulator of p53, which binds to p53 and degrades p53 through ubiquitation. MDM2 itself is a transcriptional target of p53, and therefore, MDM2 forms a negative feedback loop with p53 to tightly regulate p53 levels and function. microRNAs (miRNAs) play a key role in regulation of gene expression. miRNA dysregulation plays an important role in tumorigenesis. In this study, we found that miRNA miR-1827 is a novel miRNA that targets MDM2 through binding to the 3'-UTR of MDM2 mRNA. miR-1827 negatively regulates MDM2, which in turn increases p53 protein levels to increase transcriptional activity of p53 and enhance p53-mediated stress responses, including apoptosis and senescence. Overexpression of miR-1827 suppresses the growth of xenograft colorectal tumors, whereas the miR-1827 inhibitor promotes tumor growth in mice in a largely p53-dependent manner. miR-1827 is frequently down-regulated in human colorectal cancer. Decreased miR-1827 expression is associated with high MDM2 expression and poor prognosis in colorectal cancer. In summary, our results reveal that miR-1827 is a novel miRNA that regulates p53 through targeting MDM2, and highlight an important role and the underlying mechanism of miR-1827 in tumor suppression.

[Proliferative and invasive effects of inhibitors of kinase 4(P15(ink4b) and P16(ink4a)/CDKN2) gene activation on RKO human colorectal cancer cells].

OBJECTIVE: To explore the proliferation and invasive effects of inhibitors of kinase 4(INK4)(P15(ink4b) and P16(ink4a)/CDKN2) gene protein activation on RKO human colorectal cell in vivo and in vitro. METHODS: RKO human colorectal cell line was exposed to the specific DNA methyltransferase inhibitor 5-Aza-CdR and INK4(P15(ink4b) and P16(ink4a)/CDKN2) protein expression was detected by Western blotting. Soft agar cloning experiment and Transwell chamber assay were used to detect the proliferative and invasive ability in vitro. Tumorigenicity in nude mice was analyzed in vivo. RESULTS: INK4(P15(ink4b) and P16(ink4a)/CDKN2) protein expression of RKO human colorectal cells after exposure to 1×10(-7), 5×10(-7) and 1×10(-6) mol/L 5-Aza-CdR concentrations(A, B, C groups) were 1.13, 1.38, 1.92 folds and 1.11, 1.45, 2.14 folds compared to positive control group respectively. Soft agar cloning experiment showed the number of cell colony significantly decreased from 36.8±5.1(positive control group) to 32.4±7.2, 21.3±5.4 and 19.5±6.4 (3 experiment groups, all P<0.05) respectively. Transwell chamber assay showed that migrated cell number in positive control group(67.4±7.2) was significantly higher than those of 3 experimental groups(35.3±4.6, 29.5±7.3 and 25.3±6.2, respectively). The tumor volume of metastasis model in nude mice was inhibited in experimental groups, but not significantly lower compared to control group (P>0.05). There were significant differences of tumor weight and inhibition rate between control group and 3 experimental groups in nude mice respectively(all P<0.01). CONCLUSION: INK4(P15(ink4b) and P16(ink4a)/CDKN2) protein activation can inhibit tumor proliferation, migration and suppress the tumor formation ability.

Secreted protein acidic and rich in cysteines-like 1 suppresses aggressiveness and predicts better survival in colorectal cancers.

PURPOSE: Secreted protein acidic and rich in cysteines-like 1 (SPARCL1) is an extracellular matrix glycoprotein with malignancy-suppressing potential. The hypothesis that SPARCL1 reduces cancer invasiveness and predicts better survival in colorectal cancers (CRC) was investigated. EXPERIMENTAL DESIGN: Stable SPARCL1 transfectants, RKO-SPARCL1, and corresponding vector control were constructed and implanted into nude mice to generate a mouse xenograft model of liver metastasis. Also, a retrospective outcome study was conducted on the COH set (222 CRCs) and ZJU set (412 CRCs). The protein expression level of SPARCL1 was determined by immunohistochemistry. The Kaplan-Meier and Cox analyses were used for survival analysis. The association of SPARCL1 with mesenchymal-epithelial transition (MET) was examined by reverse transcription PCR (RT-PCR) and Western blot analysis. RESULTS: The ectopic expression of SPARCL1 significantly reduced the potential for anchorage-independent growth, migration, invasion and induced cell differentiation in RKO and SW620 cells. In mouse xenograft model, the expression of SPARCL1 significantly reduced the liver metastasis (P < 0.01). The patient-based studies revealed that the expression of SPARCL1 was related to better differentiation (P < 0.01), less lymph node involvement [OR, 0.67; 95% confidence interval (CI), 0.45-1.00], and less distant metastasis (OR, 0.38; 95% CI, 0.18-0.79). The Kaplan-Meier and Cox analysis showed that the expression of SPARCL1 was associated with better overall survival (log-rank: P < 0.01; HR, 0.57; 95% CI, 0.39-0.84). Transfection of SPARCL1 induced MET of colon cancer cells. CONCLUSION: SPARCL1 functions as a tumor suppressor promoting differentiation possibly via MET, which inhibits the aggressiveness of CRCs.

Overexpression of HMGA2 promotes metastasis and impacts survival of colorectal cancers.

PURPOSE: This study aims to address the hypothesis that the high-mobility group A2 (HMGA2), an oncofetal protein, relates to survivability and serves as a prognostic biomarker for colorectal cancer (CRC). EXPERIMENTAL DESIGN: This is a retroprospective multiple center study. The HMGA2 expression level was determined by performing immunohistochemistry on surgical tissue samples of 89 CRCs from a training set and 191 CRCs from a validation set. The Kaplan-Meier analysis and COX proportional hazard model were employed to analyze the survivability. RESULTS: Multivariate logistic analysis indicated that the expression of HMGA2 significantly correlates with distant metastasis in training set (odds ratio, OR = 3.53, 95% CI: 1.37-9.70) and validation set (OR = 6.38, 95% CI: 1.47-43.95). Survival analysis revealed that the overexpression of HMGA2 is significantly associated with poor survival of CRC patients (P < 0.05). The adjusted HRs for overall survival were 2.38 (95% CI: 1.30-4.34) and 2.14 (95% CI: 1.21-3.79) in training and validation sets, respectively. Further investigation revealed that HMGA2 delays the clearance of γ-H2AX in HCT-116 and SW480 cells post γ-irradiation, which supports our finding that CRC patients with HMAG2-positive staining in primary tumors had augmented the efficacy of adjuvant radiotherapy (HR = 0.18, 95% CI: 0.04-0.63). CONCLUSION: Overexpression of HMGA2 is associated with metastasis and unequivocally occurred in parallel with reduced survival rates of patients with CRC. Therefore, HMGA2 may potentially serve as a biomarker for predicting aggressive CRC with poor survivability and as an indicator for better response of radiotherapy.

[Effects of 5-Aza-2'-deoxycytidine on the carcinogenesis of colorectal cancer in mouse and the in vivo expression of p16/CDKN(2) mRNA].

OBJECTIVE: To explore the effects and relationship of specific demethylation agent 5-Aza-2'-deoxycytidine (5-Aza-CdR) on colorectal cancer (CRC) induced by 1, 2-dimethylhydrazine (DMH) in mouse and the in vivo expression of cyclin-dependent kinases inhibitor p16/CDKN(2) mRNA. METHODS: A total of 40 male KM mice were randomized into 2 groups and CRC was induced by a 22-week injection of DMH. One group was interfered by specific DNA methyltransferase inhibitor 5-Aza-CdR. Another 10 the same source male KM mice were induced by a 22-week injection of saline as none induced cancer control group (negative control group). All mice were sacrificed to examine for colorectal neoplasm. Immunohistochemical staining was used to assess the expression of proliferating cell nuclear antigen (PCNA). The expression of p16/CDKN(2) mRNA was detected by in situ hybridization. RESULTS: The average numbers of neoplasm was higher in the DMH group (7.6 ± 3.1) than that of the group DMH + 5-Aza-CdR (3.4 ± 1.8, P < 0.05). Immunohistochemical staining showed there was a significant elevation of PCNA in the group DMH (16/19) as compared with that in the group DMH + 5-Aza-CdR (11/19, P < 0.05). In situ hybridization revealed that the level of tumor suppressor gene p16/CDKN(2) mRNA was significantly lower in the group DMH than that in the group DMH + 5-Aza-CdR. CONCLUSION: The specific demethylation agent 5-Aza-2'-deoxycytidine may inhibit the carcinogenesis of CRC. Its mechanism may be related with a high expression of p16/CDKN(2) mRNA.

[Detection of chromosomal aberration in sporadic colorectal cancer with comparative genomic hybridization].

OBJECTIVE: To investigate the chromosomal aberration in sporadic colorectal carcinoma and its association with clinicopathological features. METHODS: Comparative genomic hybridization(CGH) was used to screen the changes in the number of DNA sequence copies in 40 sporadic colorectal cancer patients in order to identify regions that contain genes important for the development and progression of colorectal cancer. RESULTS: In 40 sporadic colorectal cancer, frequent gain at 20 q, 12 q, 13 q, 7 p, 7 q and 16 q were found, while loss was also found at 18 q, 5 q, 4 q, 8 pand 17 p. The number of chromosomal aberration was closely associated with tumor stage(P<0.05). No significant association was found between the number of chromosomal aberration and tumor site, histopathologic type and histologic grade. CONCLUSIONS: Chromosomal aberration exists generally in sporadic colorectal carcinoma. The number of chromosomal aberration and gain of 20q are closely associated with tumor stage.

[Effect of microRNA143 expression on cell proliferation in colonic carcinoma].

OBJECTIVE: To investigate the effect of microRNA143 on cell proliferation and K-ras expression in colorectal carcinoma. METHODS: Northern blot was used to examine the expression of miR-143 in colorectal carcinoma and adjacent normal tissues. A miR-143 expression vector was constructed and transfected into a human colon adenocarcinoma cell line SW480. Cell proliferation was evaluated by MTT assay. RT-PCR and Western blot were used to examine the expression of K-ras oncogene in transfected cells. RESULTS: The level of mature miR-143 was lower in tumors compared with adjacent normal tissues in 81% of colorectal carcinoma specimens. In transfected cells, the increased accumulation of miR-143 inhibited the cell proliferation, and resulted in approximately 40.3% decrease of K-ras protein levels, but had no effect on level of K-ras mRNA. CONCLUSION: The increased accumulation of miR-143 inhibits the proliferation of transfected cells, and results in down-regulation of K-ras protein in colorectal carcinoma.

[Influence of microencapsulated ovary cells modified with maspin gene on the microvessel density and lung metastasis of breast carcinoma].

OBJECTIVE: To observe the inhibition of maspin on the angiogenesis in tumor and lung metastasis of breast carcinoma and the feasibility of treatment of tumor by microencapsulated transgene cells in vivo. METHODS: Microencapsulated Chinese hamster ovarian epithelial cells (CHO) modified with maspin gene, CHO/pcDNA3.1/maspin cells, were prepared. Twenty BALB/C nude rats underwent subcutaneous injection of breast carcinoma cells of the line Bcap37 to establish tumor-loaded animal models and then randomly divided into 2 groups: maspin group, undergoing subcutaneous injection of CHO/pcDNA3.1/maspin cells next to the transplanted tumor, and control group undergoing subcutaneous injection of microencapsulated CHO/pcDNA3.1 cells. One month later, the rats were killed and the size and microvessel density (MVD) of the transplanted tumor and metastatic tumor in lung were observed. RESULTS: The MVD of the transplanted tumor of the maspin group was 26 +/- 9, significantly lower than that of the control group (60 +/- 16, P < 0.05). The lung metastatic rate of the maspin group was 15%, significantly lower than that of the control group (55%, P < 0.05). CONCLUSION: Maspin may inhibit the MVD in tumor and the occurrence of metastatic tumor in lung. It is feasible to use microencapsulated transgene cells as tumor-killer.

Expression of SNC73, a transcript of the immunoglobulin alpha-1 gene, in human epithelial carcinomas.

AIM: To investigate the expression of SNC73, a trans-cript of the immunoglobulin alpha-1 gene (IgA1-H chain), in human epithelia-derived tumor cells. METHODS: Total RNAs and cell lysates were prepared from five different human epithelial cell lines derived from lung, stomach, liver, skin, and breast, respectively. RT-PCR and immunoblot analysis of these five cell lines were done. Both RT-PCR and immunochemistry were used to detect the expression of SNC73 in these cell lines. We also examined the expression of SNC73 in normal epithelial cells of colon mucosa by in situ hybridization. RT-PCR and immunoblot analysis were used to determine whether the recombination activating gene1/2 (RAG1 and RAG2) is present. The expression of three immunoglobulin transcription factors, EBF, E2A and Pax5, and the heavy chain of IgA1 and two types of light chains of immunoglobulin (kappa and lambda) in the aforementioned cell lines were analyzed by RT-PCR and immunochemistry, respectively. All the RT-PCR products were analyzed by sequencing. RESULTS: The results of RT-PCR and immunochemistry showed that both mRNA and protein of SNC73 were expressed in five human epithelia-derived cancer cell lines. These data were further confirmed in the normal epithelial cells of colon mucosa by in situ hybridization. Also, the heavy chain of IgA1 and kappa light chain were detected in these cells, but no lambda light chain was obse-rved. Both RAG1 and RAG2 were expressed in these human epithelia-derived cancer cell lines and the sequence was identical to that expressed in pre-B and pre-T cells. In addition to RAG1 and RAG2, the mRNA in one of the immunoglobulin transcription factors, EBF, was also detected in these cell lines, and Pax5 was only expressed in SW480 cells, but no expression of E2A was observed in all the five cell lines. CONCLUSION: Immunoglobulin A1 is originally expressed and V(D)J recombination machine is also present in non-lymphoid cells, suggesting that V(D)J recombination machine mediates the assembly of immunoglobulin A1 in non-lymphoid cells as in pre-lymphocytes.

[Establishment of DNA oxidative damage model in colorectal crypt cells by hydrogen peroxide].

OBJECTIVE: To induce DNA oxidative damage in colorectal crypt cells by hydrogen peroxide in vitro. METHODS: Hydrogen peroxide was diluted into 100, 50, 10, 5 and 1 micromol/L with RPMI 1640. Colorectal crypt cells were treated with peroxide for 10 min, 30 min, 1 h, 1.5 h, 12 h and 24 h respectively. The survival of colorectal crypt cell was measured by MTT method, and the DNA oxidative damage special product, 8-OhdG was detected with immunohistochemical staining. Liner regression was used to measure the time trend of survival rate with SPSS 10.0 software. RESULT: Survival rate of colorectal crypt cell was 60% and 80% after 10 min of hydrogen peroxide treatment. The longer treatment of hydrogen peroxide, the lower survival rate; the survival rate was reduced to 30% in 24 h. After 10 or 30 min treatment of 100 or 50 micromol/L hydrogen peroxide, the survival rates of colorectal crypt cells were reduced by 20% compared with those of 10, 5 and 1 micromol/L hydrogen peroxide. However, while cells were treated with different concentrations of hydrogen peroxide for 1.0 h or above, there were no differences in cell survival rates. The time trend test results demonstrated that the survival rates of colorectal crypt cells treated with 10, 5 and 1 micromol/L hydrogen peroxide were significantly decreased with the time length of treatment. Colorectal crypt cells treated with different concentrations of hydrogen peroxide for 15 minutes were positively stained brown in cytoplasm and nuclear by immunohistochemistry with 8-OhdG monoclonal antibody. CONCLUSION: Hydrogen peroxide could induce DNA oxidative damage in colorectal crypt cells. And treated with 1 - 10 micromol/L hydrogen peroxide for 10 - 30 min, DNA oxidative damage is apt to be induced in colorectal crypt cell.

Prognostic significance of bcl-2 and p53 expression in colorectal carcinoma.

OBJECTIVE: This study was designed to detect the expression of bcl-2 and p53 proteins in colorectal carcinomas and to determine their association with the patient survival and stage of the diseases. METHODS: Immunohistochemistry method was used to detect the expression of bcl-2 and p53 proteins in 93 cases of colorectal carcinoma. The stain results were obtained by analyzing the clinic-pathological characteristics of patients. RESULTS: Fifty-seven percent (53/93) of the colorectal carcinomas were bcl-2 protein positive. The positive rate of bcl-2 protein in lymph node involvement cases was lower (15/37) than the cases without node involvement (38/58, P<0.01). The positive rate of p53 protein was 43% (40/93) in colon-rectum carcinomas. No significant correlation was observed between p53 protein expression and clinic-pathological manifestations (P>0.05) but the survival was significantly worse (P=0.0001) in the p53 protein positive cases. Neither bcl-2 nor p53 alone was correlated with stage of the disease. When combined bcl-2/p53 status was analyzed, a group with bcl-2(+) and p53(-) had the best prognosis. This group was significantly associated with earlier Dukes' stages (P=0.1763). In multivariate Cox regression analysis, lymph node involvement and p53 protein expression were two independent factors correlated with survival time. CONCLUSION: The expression of bcl-2 and p53 represent biological characteristics of colorectal carcinomas. Assessment of both bcl-2 and p53 status may be valuable in predicting the prognosis of patients.

[Development of ZM-1 tissue microarrayer].

ZM-1 tissue microarrayer designed by our group is manufactured in stainless steel and brass. It features an easier and faster preparation for tissue microarrays. By means of it, a group of biopsy needles are used to punch the donor tissue specimens respectively, and all the needles with the punched specimen cylinders are arranged into the array-board, where small holes have been digged to fit the needles. All the specimen cylinders arraying and the tissue microarray block's shaping are finished simultaneously. ZM-1 tissue microarrayer with a lower cost of manufacture, is capable of preparing the tissue microarrays conveniently, efficiently and quality-controllably.

Application of new tissue microarrayer-ZM-1 without recipient paraffin block.

The ZM-1 tissue microarrayer designed by our groups is manufactured in stainless steel and brass and contains many features that make TMA (tissue microarray) paraffin blocks construction faster and more convenient. By means of ZM-1 tissue microarrayer, biopsy needles are used to punch the donor tissue specimens respectively. All the needles with the punched specimen cylinders are arrayed into the array-board, with an array of small holes dug to fit the needles. All the specimen cylinders arraying and the TMA paraffin block shaping are finished in only one step so that the specimen cylinders and the paraffin of the TMA block can very easily be incorporated and the recipient paraffin blocks need not be made in advance, and the paraffin used is the same as that for conventional pathology purpose. ZM-1 tissue microarrayer is easy to be manufactured, does not need any precision location system, and so is much cheaper than the currently used instrument. Our method's relatively cheap and simple ZM-1 tissue microarrayer technique of constructing TMA paraffin block may facilitate popularization of the TMA technology.

Preparation and in vitro studies of microencapsulated cells releasing human tissue inhibitor of metalloproteinase-2.

OBJECTIVE: To prepare microencapsulated cells releasing human tissue inhibitor of metalloproteinase-2 (TIMP-2), and investigate their biological characteristics in vitro. METHODS: Chinese hamster ovary (CHO) cells were stably transfected with a human TIMP-2 expression vector, encapsulated in barium alginate microcapsules and cultured in vitro. Morphological appearance of the microcapsules was observed under a light microscope. Cell viability was assessed using MTT (3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide) assay. Enzyme linked immunosorbent assay (ELISA) and reverse zymography were used to confirm the release of biologically active TIMP-2 from the microcapsules. Cryopreservation study of the microencapsulated cells was carried out using dimethyl sulfoxide (DMSO) as preservative agent. RESULTS: The microcapsules appeared like a sphere with diameter of 300 - approximately 600 microm. The surface of the capsule wall was clearly smooth. The microencapsulated cells survived well and kept proliferating over the 6 weeks observed. No significant difference in TIMP-2 secretion was found between encapsulated and unencapsulated cells. Reverse zymography confirmed the bioactivity of MMP (matrix metalloproteinase) inhibition of TIMP-2. The cryopreservation process did not damage the microcapsule morphology nor the viability of the cells inside. CONCLUSION: Microencapsulated engineered CHO cells survive at least 6 weeks after preparation in vitro, and secrete bioactive TIMP-2 freely from the microcapsules.

[Effects of microencapsulated CHO cells modified with maspin gene on the motility and adhesiveness of breast carcinoma cells Bcap37].

OBJECTIVE: To investigate the effects of microencapsulated Chinese hamster ovary (CHO) cells modified with maspin gene on the motility and adhesiveness of breast carcinoma cells Bcap37 and to explore the possibility and feasibility of its clinical application in treatment of malignant tumors. METHODS: After the Bcap37 cells were co-cultured with the microencapsulated CHO cells modified with maspin gene, their motility and adhesion to vascular endothelial cells (ECV304), changes in CD44v6 and E-cadherin expression were examined. RESULTS: After the treatment, the motility of Bcap37 cells, their adhesion to vascular endothelial cells ECV304 and the CD44v6 expression were significantly reduced. The adhesiveness of Bcap37 cells and their E-cadherin expression were significantly enhanced. CONCLUSION: The microencapsulated CHO cells modified with maspin gene decrease motility and adhesiveness of breast carcinoma cells Bcap37, which help explain the anti-metastatic effects of maspin.

[Clinical analysis of 39 cases of heterotopic gastric mucosa in the upper esophagus].

OBJECTIVE: To determine accurately the incidence of heterotopic gastric mucosa in the upper esophagus (HGMUE) in China, and to study the macroscopic and microscopic aspects of the lesions and to evaluate the clinical importance of HGMUE. METHODS: A prospective study was made among a total of 15,228 consecutive patients, 8,573 male and 6,655 female, aged 54 (8-95), undergoing gastroscopy. Disease histories of all patients were carefully inquired, especially those regarding possible complaints including discomfort of throat and swallowing pain and so on. Special care was taken in the upper esophageal sphincter area to make sure whether the area was adequately inspected. Biopsy specimens from aberrant mucosa were obtained and the sections were stained with haematoxylin and eosin, and Giemsa stain for Helicobacter pylori. RESULTS: HGMUE was found in 39 patients (0.26%) with an average age of 50. Five patients with H. pylori infection in heterotopic gastric mucosa also presented the infection in the stomach. The gastric mucosa was gastric body type in 8 patients, transitional type in 11 patients, and antral pattern in 7 patients. Intestinal metaplasia was found in 5 patients, and mild atypical hyperplasia in 2 patients. An impressive finding was coexistent erosive gastritis in 14 patients (35.9%), Barrett's esophagus in one patient (2.6%), peptic ulcer in 8 patients (20.5%), and a patient had the complication of constriction in the upper esophagus. CONCLUSION: HGMUE is not rare in China. The presence of inlet patches is possibly correlated with specific symptoms. There are some severe complications in HGMUE, especially esophageal constriction. Close surveillance should be taken for rare cases with metaplasia or dysplasia in HGMUE.