[Transvaginal endoscopic resection of rectal tumor: a report of 2 cases].

Two female patients with rectal tumor undergoing proctectomy via vagina, namely natural orifice transluminal endoscopic surgery (NOTES), are reported. The operations were performed on June 8 and August 10, 2010, respectively. No Trocar was used in the abdomen except for the transumbilical incision. There were no visible scars in the abdomen. Tubulovillous adenoma and moderately differentiated adenocarcinoma were diagnosed respectively through postoperative pathological examination. Both patients resumed normal work and life at the most recent follow up. Sexual life was satisfactory.

[The effect of As2O3 on induction of apoptosis and inhibition of telomerase activity in colon cancer LS-174T cells].

OBJECTIVE: To study the impact of arsenic trioxide (As2O3) on human colorectal carcinoma LS-174T cells and their activity of telomerase. METHODS: LS-174T cells and xenograft model of nude mice were treated with As2O3. The inhibitory effect of As2O3 on survival of LS-174T cells was determined by MTT assay. Apoptosis was determined by electron microscopy and fluorescence microscopy. Cell cycle was assessed by flow cytometry. Telomerase activity in LS-174T cells was determined by PCR-ELISA kit. RESULTS: With the increasing concentration of As2O3, the ratio of living cells to dead cells decreased significantly, and the IC50 value was 5.23 micromol/L. Apoptosis curve appeared after 24 h and cells turned to apoptosis in a time-dependent manner. As2O3 inhibited the telomerase activity in cell extraction, obviously in a concentration-dependent and time-dependent manner. Inhibitiory effect of As2O3 on xenograft model of nude mice was observed by tumor volume and weight measurement, showing a significant difference between As2O3 and control groups (P < 0.05). CONCLUSION: Both the experiments in vitro and in vivo showed an inhibitory effect of As2O3 on colonrectal cancer S-174T cell growth, probably by induction of apoptosis and inhibition of telomerase activity.

[Radiosensitivity on colorectal neoplasms by recombinant adenoviral-mediated wild-type p53 gene].

OBJECTIVE: To study the radiosensitization on the cells of colorectal cancer transfected with recombinant adenovirus vector-mediated wild-type p53. METHODS: SW480 cells transfected by wild-type p53 were treated with 4 Gy and 6 Gy radiation. The expression of recombinant adenovirus vector-mediated wild-type p53 gene was detected by Western blotting. The inhibition rate of SW480 cells was examined by MTT, apoptotic rate by TdT-mediated dUTP nick end labeling (TUNEL) and proliferating cell nuclear antigen (PCNA) by immunohistochemical method. RESULTS: SW480 cells transfected by wild-type p53 were inhibited significantly by 4 Gy and 6 Gy radiation. The level of apoptosis increased and the expression of PCNA decreased. CONCLUSION: Cells of colorectal carcinoma transfected with wild-type p53 increases their radiation sensitivity.

[Inducement of FLICE inhibitory protein antisense oligonucleotides on apoptosis of human gastric cancer cell line BGC823].

BACKGROUND & OBJECTIVE: Cellular FLICE inhibitory protein (cFLIP) plays an important role in cell apoptosis, researches of antisense oligonucleotides (ASODN) of cFLIP gene may provide a new method or protocol for treatment of human gastric cancer. This study was to explore effect of cFLIP ASODN on apoptosis of human gastric cancer cell line BGC823. METHODS: Human cervical cancer cell line HeLa was used as control, cFLIP ASODN was introduced into BGC823 cells and HeLa cells, reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot were used to detect cFLIP(L/S) (cellular FLIP(Short) and cellular FLIP(long)) mRNA and protein. The 5'FAM-conjugated ASODN was created complementary to a sequence that included the start site of FLIP open reading frame. After introducing, MTT was used to detect cell inhibition rate,TUNEL and flow cytometry (FCM) were used to detect cell apoptosis, and Western blot was used to detect protein level of cFLIP. RESULTS: The encoding mRNA and protein of cFLIP(L) and cFLIP(S) can be detected in both HeLa and BGC823 cells. MTT revealed that cFLIP ASODN significantly inhibited proliferation of BGC823 cells (P< 0.05) in a concentration-dependent manner. TUNEL staining detected positive FLIP expression, specific apoptotic peak can be detected before G1 peak by FCM, and Western blot revealed that protein level of cFLIP(L) and cFLIP(S) decreased significantly (P< 0.05). CONCLUSION: The cFLIP(L/S) mRNA and encoded proteins expressed in both HeLa and BGC823 cells. ASODN may down-regulate cFLIP(L/S) protein level, and initiate apoptosis of BGC823 cells.

Relations of the type and branch of surface N-glycans to cell adhesion, migration and integrin expressions.

The relations between the structure of cell surface N-glycans to cell behaviors were studied in H7721 human hepatocarcinoma cell line, which predominantly expressed complex-type N-glycans on the surface. 1-Deoxymannojirimycin (DMJ) and swaisonine (SW), the specific inhibitor of Golgi alpha-mannosidase II or I, were selected to block the processing of N-glycans at the steps of high mannose and hybrid type respectively. All-trans retinoic acid (ATRA) and antisense cDNA of N-acetylglucosaminyltransferase-V (GnT-V) were used to suppress the expression of GnT-V and decreased the GlcNAc beta1,6-branching or tri-/tetra-antennary structure of surface N-glycans. The structural alterations of N-glycans were verified by sequential lectin affinity chromatography of [3H] mannose-labeled glycans isolated from the cell surface. The cell adhesions to fibronectin (Fn) and human umbilical vein epithelial cell (HUVEC), as well as cell migration (including chemotaxis and invasion) were selected as the parameters of cell behaviors. It was found that cell adhesion and migration were significantly decreased in SW and DMJ treated cells, suggesting that complex type N-glycan is critical for the above cell behaviors. ATRA and antisense GnTV enhanced cell adhesion to Fn but reduce cell adhesion to HUVEC and cell migration. These results reveal that cell surface complex-type N-glycans with GlcNAc beta1,6 branch are more effective than those without this branch in the cell adhesion to HUVEC and cell migration, but N-glycan without GlcNAc beta1,6-branch is the better one in mediating the cell adhesion to Fn. The integrin alpha5beta1 (receptor of Fn) on cell surface was unchanged by DMJ and SW. In contrast, ATRA up regulated alpha5, but not beta1, and antisense GnT-V decreased both alpha5 and beta1. This findings suggest that both the structure of N-glycan and the expression of integrin on cell surface are two of the important factors in the determination of cell adhesion to Fn, a complex biological process.

Regulation on the expression and N-glycosylation of integrins by N-acetylglucosaminyltransferase V.

The expressions of integrin alpha5, beta1, and alpha6 were studied in H7721 cells by means of flow cytometric and RT-PCR method after transfected with sense and antisense cDNA of N-acetylglucosaminyltransferase V (GnT-V). The transfected cells were characterized by Northern blot. It was found that the order of expression from high to low was beta1>alpha5>alpha6. Transfection of sense GnT-V up-regulated alpha5 and alpha6, but not beta1 subunit, while antisense GnT-V down-regulated alpha5 and beta1, but not alpha6. The alterations of surface integrin subunits were quite compatible with the changes of their mRNAs. Using enzyme-labeled lectin analysis, it was shown that alpha5 subunit contained only C(2)C(2) biantennary N-glycan, which was not regulated by sense and antisense GnT-V. In contrast, beta1 subunit contained both biantennary and tri-/tetra-antennary N-glycans with GlcNAcbeta1,6Manalpha1,6-branch, and the latter was up- and down-regulated by the sense and antisense GnT-V, respectively. Therefore, the amount of biantennary N-glycans on beta1 subunit, but not the integrin protein, was correlated to the cell adhesion to fibronectin and laminin, which was reduced and elevated in the sense and antisense GnT-V-transfected cells, respectively, as we previously reported.

Alteration in the expression of early stage processing enzymes of N-glycan during myeloid and monocytoid differentiation of HL-60 cells.

The expressions of the enzymes participating in the early stage of N-glycan processing, Golgi alpha-Mase-I, alpha-Mase-II and GnT-I, GnT-II, were studied before and after HL-60 cells were differentiated to myelocytes or monocytes induced by ATRA or PMA, respectively. It was found that alpha-Mase-I activity and GnT-I mRNA were decreased by both ATRA and PMA, while alpha-Mase-II and GnT-II were altered insignificantly. The down-regulation of alpha-Mase-I and GnT-I was cell specific, since ATRA up-regulated alpha-Mase-I and GnT-I in the H7721 hepatocarcinoma cell line. However, in H7721 cells, PMA also decreased alpha-Mase-I and GnT-I, and both ATRA and PMA also did not obviously change the expressions of alpha-Mase-II and GnT-II.

Lewis Antigens, alpha1,3 Fucosyltransferses and the Metastatic Potential of Human Primary Liver Cancer.

In order to study the expression of Lewis antigens and the subtypes of alpha1,3 fucosyltransferase(alpha1,3FucT) in human primary liver cancer, and their relations with the cancer cell embolus formation, as well as the expression of nm23-H1, a metastatic suppressor gene, Lewis antigens were detected with immunohistochemical method, and the mRNA of alpha1,3 FucTs and nm23-H1 were determined with Northern blot. Results showed that the positive rates of the expression of four Lewis antigens, sialyl Lewis X(Sle(x)), Lewis X(Le(x)), sialyl dimeric Lewis X(SDLe(x)) and sialyl Lewis A(Sle(a)), in human primary liver cancer were about 80%. The expression of Sle(x) was rather higher, Le(x) and Sle(a) were lower, but the expression of SDLe(x) was only in trace amount. The four Lewis antigens were not expressed in the liver regions adjacent to the cancer tissues. The transcriptional level of alpha1,3 FucT-III/VI mRNA in cancer tissues was higher than that in the adjacent regions, especially in the cancer tissues of patients with portal vein cancer cell embolus(CCE). However, the expression of alpha1,3 FucT-III/VI mRNA was not different in the adjacent regions in spite of the presence or absence of CCE in the patients. In contrast, the expression of alpha1,3 FucT-VII was rather lower and identical to each other both in cancer tissues and adjacent regions. In addition, it was found that the expression of nm23-H1, a metastasis suppressor gene, was markedly lower in the cancer tissues of patients with CCE than that in the non-CCE patients and the adjacent regions. Furthermore, the expression of nm23-H1 was negatively related to the expression of alpha1,3 FucT-III/VI. These results indicated that the expression of alpha1,3 FucT-III/VI and its product Sle(x) were correlated with CCE (metastatic potential), and the down-regulation of alpha1,3 FucT-III/VI and Sle(x) may be one of the mechanisms of nm23-H1 to inhibit liver cancer metastasis.