MEIS2C and MEIS2D promote tumor progression via Wnt/ß-catenin and hippo/YAP signaling in hepatocellular carcinoma.

BACKGROUND: MEIS2 has been identified as one of the key transcription factors in the gene regulatory network in the development and pathogenesis of human cancers. Our study aims to identify the regulatory mechanisms of MEIS2 in hepatocellular carcinoma (HCC), which could be targeted to develop new therapeutic strategies. METHODS: The variation of MEIS2 levels were assayed in a cohort of HCC patients. The proliferation, clone-formation, migration, and invasion abilities of HCC cells were measured to analyze the effects of MEIS2C and MEIS2D (MEIS2C/D) knockdown with small hairpin RNAs in vitro and in vivo. Chromatin immunoprecipitation (ChIP) was performed to identify MEIS2 binding site. Immunoprecipitation and immunofluorescence assays were employed to detect proteins regulated by MEIS2. RESULTS: The expression of MEIS2C/D was increased in the HCC specimens when compared with the adjacent noncancerous liver (ANL) tissues. Moreover, MEIS2C/D expression negatively correlated with the prognosis of HCC patients. On the other hand, knockdown of MEIS2C/D could inhibit proliferation and diminish migration and invasion of hepatoma cells in vitro and in vivo. Mechanistically, MESI2C activated Wnt/ß-catenin pathway in cooperation with Parafibromin (CDC73), while MEIS2D suppressed Hippo pathway by promoting YAP nuclear translocation via miR-1307-3p/LATS1 axis. Notably, CDC73 could directly either interact with MEIS2C/ß-catenin or MEIS2D/YAP complex, depending on its tyrosine-phosphorylation status. CONCLUSIONS: Our studies indicate that MEISC/D promote HCC development via Wnt/ß-catenin and Hippo/YAP signaling pathways, highlighting the complex molecular network of MEIS2C/D in HCC pathogenesis. These results suggest that MEISC/D may serve as a potential novel therapeutic target for HCC.

Analysis of histone modifications at human ribosomal DNA in liver cancer cell.

Human liver cancer is the cancer commonly seen clinically. The transcription of ribosomal DNA (rDNA) is a critical step for cells, and epigenetic marks such as post-translational histone modifications have been involved in the regulation of rDNA transcription. But less is known about the pathogenesis of the liver cancers concerning the rDNA transcription regulation. Here we aligned the ChIP-seq data of histone modification markers and CTCF to the human genome assembly which contains a single rDNA repeat in human liver cancer cell and validated their distribution with ChIP-QPCR. Human liver cancer cell possesses a higher enrichment of H3K4me1 and H3K27me3 at ~28 kb within the intergenic spacer (IGS) of rDNA and a higher enrichment of H3K4me3 and H3K27ac upstream of TSS. Furtherly, we studied whether UBF could affect histone modification markers and CTCF at rDNA in human liver cancer cell. UBF depletion leads to a decrease of gene activation mark H3K4me3 across the rDNA promoter. And other histone modification marks and CTCF were not altered after UBF depletion. Taken together, our data showed a high resolution map of histone modification marks at rDNA in human liver cancer cell and provide novel evidence to decipher chromatin-mediated regulation of rDNA in liver cancer.

Co-culture of apoptotic breast cancer cells with immature dendritic cells: a novel approach for DC-based vaccination in breast cancer

A dendritic cell (DC)-based vaccine strategy could reduce the risk of recurrence and improve the survival of breast cancer patients. However, while therapy-induced apoptosis of hepatocellular and colorectal carcinoma cells can enhance maturation and antigen presentation of DCs, whether this effect occurs in breast cancer is currently unknown. In the present study, we investigated the effect of doxorubicin (ADM)-induced apoptotic MCF-7 breast cancer cells on the activation of DCs. ADM-induced apoptotic MCF-7 cells could effectively induce immature DC (iDC) maturation. The mean fluorescence intensity (MFI) of DC maturity marker CD83 was 23.3 in the ADM-induced apoptotic MCF-7 cell group compared with 8.5 in the MCF-7 cell group. The MFI of DC co-stimulatory marker CD86 and HLA-DR were also increased after iDCs were treated with ADM-induced apoptotic MCF-7 cells. Furthermore, the proliferating autologous T-lymphocytes increased from 14.2 to 40.3% after incubated with DCs induced by apoptotic MCF-7 cells. The secretion of interferon-γ by these T-lymphocytes was also increased. In addition, cell-cell interaction between apoptotic MCF-7 cells and iDCs, but not soluble factors released by apoptotic MCF-7 cells, was crucial for the maturation of iDCs. These findings constitute a novel in vitro DC-based vaccine strategy for the treatment of breast cancer by ADM-induced apoptotic MCF-7 cells.

Co-culture of apoptotic breast cancer cells with immature dendritic cells: a novel approach for DC-based vaccination in breast cancer.

A dendritic cell (DC)-based vaccine strategy could reduce the risk of recurrence and improve the survival of breast cancer patients. However, while therapy-induced apoptosis of hepatocellular and colorectal carcinoma cells can enhance maturation and antigen presentation of DCs, whether this effect occurs in breast cancer is currently unknown. In the present study, we investigated the effect of doxorubicin (ADM)-induced apoptotic MCF-7 breast cancer cells on the activation of DCs. ADM-induced apoptotic MCF-7 cells could effectively induce immature DC (iDC) maturation. The mean fluorescence intensity (MFI) of DC maturity marker CD83 was 23.3 in the ADM-induced apoptotic MCF-7 cell group compared with 8.5 in the MCF-7 cell group. The MFI of DC co-stimulatory marker CD86 and HLA-DR were also increased after iDCs were treated with ADM-induced apoptotic MCF-7 cells. Furthermore, the proliferating autologous T-lymphocytes increased from 14.2 to 40.3% after incubated with DCs induced by apoptotic MCF-7 cells. The secretion of interferon-γ by these T-lymphocytes was also increased. In addition, cell-cell interaction between apoptotic MCF-7 cells and iDCs, but not soluble factors released by apoptotic MCF-7 cells, was crucial for the maturation of iDCs. These findings constitute a novel in vitro DC-based vaccine strategy for the treatment of breast cancer by ADM-induced apoptotic MCF-7 cells.

Improvement of dendritic-based vaccine efficacy against hepatitis B virus-related hepatocellular carcinoma by two tumor-associated antigen gene-infected dendritic cells.

Recently, studies on dendritic cell (DC) vaccine have focused on the development of more effective DC vaccine regimen, such as the application of multiple tumor-associated antigen-targeted DC vaccine. This approach could be used to enhance efficacy of DC-based vaccine against tumors and infectious diseases. In this study, we analyzed whether DC from patients with hepatocellular carcinoma can be infected with the alpha-fetoprotein (AFP) gene and/or HBsAg gene (hepatocellular carcinoma-related antigen). Further, it was examined whether vaccination using these genetically engineered DC can induce stronger therapeutic antitumor immunity. Results revealed that DC infected with AdAFP (adenovirus AFP)/HBsAg can express AFP and HBsAg by reverse transcription-polymerase chain reaction and Western blot techniques. Compared with those before transfection, the expressions of membrane molecules increased dramatically. Specific T cells generated by DCs infected with AdAFP/HBsAg specifically recognized human leukocyte antigen-matched HepG2.2.15 cell lines. Moreover, the cytotoxic activity of cytotoxic T lymphocytes against HepG2.2.15 with DCs expressing AFP was significantly augmented by coinfection with the HBsAg gene. Administration with such vaccine also significantly increased the production of interleukin-12p70 and interferon-gamma. Most importantly, in vivo results suggested that inhibitors of tumor growth were most significant in severe combined immunodeficiency mice model, which was treated with induced cytotoxic T lymphocyte by the AFP/HBsAg-DC vaccine. These results indicate that a vaccination therapy using DCs coinfected with the two tumor-associated antigen genes is an effective strategy for immunotherapy in the activation of DCs, CD4(+) T cells, and CD8(+) T cells, and may be useful in the clinical application of cancer vaccine therapy.

The efficacy and safety of percutaneous microwave coagulation by a new microwave delivery system in large hepatocellular carcinomas: four case studies.

PURPOSE: To demonstrate the efficacy and safety of percutaneous microwave coagulation treatment (PMCT) by a new microwave delivery system (Forsea Microwave) in large hepatocellular carcinomas (HCC) (> or =5 cm). MATERIALS AND METHODS: Four patients with 4 HCC lesions measuring > or =6 cm in the greatest dimension underwent PMCT by means of the Forsea Microwave microwave delivery system. Final therapeutic efficacy was evaluated with dynamic computer tomography (CT) scans performed within one month after PMCT. During and after PMCT, patients' complaints and any abnormal physical signs were recorded for safety assay. CT or ultrasound scan (US) performed immediately after the treatment was used to detect acute complications related to the treatment. Repeated dynamic CT scans were performed every three to four months thereafter to detect local disease recurrence and/or other recurrences. RESULTS: Three of these patients achieved a complete ablation of the cancer nodules (two patients with two treatment sessions and one patient with three treatment sessions). One of these patients obtained a complete ablation of the cancer nodule with two treatment sessions except the lesion of portal vein tumour thrombus (PVTT). No obvious symptomatic complication was observed except abdominal pain during and after the treatment in two of these patients. All the patients remained asymptomatic and no recurrent tumour was observed during their follow-up (1-19 months). CONCLUSIONS: PMCT by the Forsea Microwave microwave delivery system could offer a satisfactory therapeutic effect and is applicable to the treatment of large HCC.

The efficacy and safety of palonosetron compared with granisetron in preventing highly emetogenic chemotherapy-induced vomiting in the Chinese cancer patients: a phase II, multicenter, randomized, double-blind, parallel, comparative clinical trial.

PURPOSE: This clinical trial was conducted to evaluate the efficacy and safety of Palonosetron in preventing chemotherapy-induced vomiting (CIV) among the Chinese cancer patients. PATIENTS AND METHODS: Two hundred and forty patients were scheduled to be enrolled and randomized to receive a single intravenous dose of palonosetron 0.25 mg, or granisetron 3 mg, 30 min before receiving highly emetogenic chemotherapy. The primary efficacy endpoint was the complete response (CR) rate for acute CIV (during the 0-24-h interval after chemotherapy). Secondary endpoints included the CR rates for delayed CIV (more than 24 h after chemotherapy). RESULTS: Two hundred and eight patients were accrued and received study medication. CR rates for acute CIV were 82.69% for palonosetron and 72.12% for granisetron, which demonstrated that palonosetron was not inferior to granisetron in preventing acute CIV. Comparisons of CR rates for delayed CIV yielded no statistical difference between palonosetron and granisetron groups and did not reveal non-inferiority of palonosetron to granisetron. Adverse events were mostly mild to moderate, with quite low rates among the two groups. CONCLUSIONS: A single dose (0.25 mg) of palonosetron is not inferior to a single dose (3 mg) of granisetron in preventing CIV and possesses an acceptable safety profile in the Chinese population.

[FK228 promotes the IL-3 mediated proliferation and differentiation of human erythroid progenitor cells].

AIM: To investigate the role of histone deacetylases (HDACs) inhibitor FK228 in the IL-3 mediated proliferation and differentiation of human erythroid progenitor cells. METHODS: CD34(+) cells were separated from the granulocyte colony-stimulating factor(G-CSF)-mobilized peripheral blood of cancer patients and cultured for 7 days with FK228 of different concentrations, stem cell factor(SCF) and interleukin 3 (IL-3) in serum-free medium. Flow cytometry was performed to analyze the expression of CD14, GPA, CD15 and CD36 on the cells and the colony assay of erythroid cells was conducted. Then the CD36(+)GPA(-) cells were enriched and cultured with with IL-3 and 0.5 microg/L FK228 supplemented serum-free semisolid cultures and the formation test of erythroid colony was conducted. RESULTS: FK228 enhanced the generation of CD36(+) cells in a dose-dependent manner, in spite of that it displayed no influence on the generation of CD14(+) and CD15(+) cells. 0.5 g/L FK228 induced a remarkable increase in the cell number of CD36(+) cells cultured with IL-3; FK228 also significantly increased the number and size of CD36(+) cells colony cultured with IL-3 containing semisolid cultures. Moreover, FK228 augmented the formation of CD36(+) cells colony from CD36(+)GPA(-) cells cultured with IL-3. CONCLUSION: FK228 can promote the IL-3 mediated proliferation and differentiation of human erythroid progenitor cells.

[Effect of Notch ligand Delta-1 on the differentiation and maturation of erythroid progenitors in humans].

OBJECTIVE: To explore the biological effect of Notch ligand Delta-1 (Notch L delta-1) on the sIL-6R during the differentiation of erythroid hematopoiesis. METHODS: Mononuclear cells (MNCs) was isolated from the normal cord blood using Ficoll graduation solution. MNCs were enriched for CD34(+) CD38(-) cells by CD34 immunomagnetic beads and a FACS Vantage. CD34(+) CD38(-) cells was cultured for 7 days in the presence of SCF, Flt3L, TPO and IL-3 (4GFs). The cultured cells was detected for the expression of IL-6R and GPA. The subsequently enriched CD36(+) erythroid progenitors were sorted for cells with IL-6R(+) and IL-6R(-) using FACS Vantage. The CD36(+) GPA(-) IL-6R(-) cells were respectively cultured in the 4GFs, 4GFs + IL-6 or 4GFs + FP6 containing medium in the presence or absence of Notch L delta-1 for 14 days and CD36(+) GPA high red cells were counted. RESULTS: IL-6R cells accounted for 95% of CD36(+) GPA(+) cells. The CD36(+) GPA(-) cells was clearly divided into IL-6R(+) (46%) and IL-6R(-) (54%) subpopulations, the IL-6R(+) cell subpopulation formed only a few GM colonies (2.1 +/- 1.8) and a greater number of BFU-E colonies were generated from the IL-6R(-) subpopulation (58.2 +/- 18.1) (P < 0.05). The number of CD36(+) GPA high cell was (1.400 +/- 0.180) x 10(6) in the presence of FP6, lower than that [(2.460 +/- 0.190) x 10(6)] in the presence of FP6 + Notch L delta-1 (P < 0.05). CONCLUSION: Notch L delta-1 enhances the sIL-6R-mediated effects of IL-6 on the generation of erythroid cells.

[EPO mediated proliferation and differentiation of human erythroid progenitor inhibited by FK228].

AIM: To investigate the function of histone deacetylases (HDACs) inhibitor FK228 in the EPO mediated proliferation and differentiation of human erythroid progenitor. METHODS: CD34(+) cells were separated from the granulocyte colony-stimulating factor-mobilized peripheral blood of patients with cancer. They were cultured for 7 days with serum-free medium containing stem cell factor (SCF), erythropoietin (EPO) or SCF+IL-3 in the presence of escalated dosages of FK228. After immunofluorescent staining with anti-GPA-PE and anti-CD36-FITC, cell count and Flow cytometric analysis were performed; CD34(+) cells were cultured for 7 days with serum-free medium containing SCF+IL-3 and enriched for CD36(+) GPA(-) cells, which were cultured for 7 days with serum-free medium containing EPO+FK228. Then the cell count was conducted. CD36(+) GPA(-) cells were cultured for 7 days with serum-free medium containing EPO in the presence or absence of FK228 and then they were stained with annexin V and PI. RESULTS: FK228 inhibited the generation of CD36(+) GPA(high), CD36(+) GPA(low) and CD36(+) GPA(-) cells in a dosage-dependent manner. FK228 induced the apoptosis of CD36(+) GPA(high) and CD36(+) GPA(low/-) cells in the presence of EPO. CONCLUSION: FK228 can inhibit the EPO mediated proliferation and differentiation of human erythroid progenitor.

Pleiotropic role of histone deacetylases in the regulation of human adult erythropoiesis.

Histone acetylation and deacetylation play fundamental roles in transcriptional regulation. We investigated the role of histone deacetylases (HDACs) in human adult haematopoiesis, using the structurally distinct HDAC inhibitors FK228 (depsipeptide) and Trichostatin A. When CD34+ cells were cultured with interleukin (IL)-3 or stem cell factor (SCF) + IL-3, FK228 (0.5 ng/ml) specifically enhanced the generation of immature erythroid cells with a CD36+ glycophorin A (GPA)low phenotype. In semisolid cultures, FK228 promoted the formation of erythroid colonies by CD34+ cells with IL-3 and SCF + IL-3. Furthermore, upon exposure to FK228, CD34+ cell-derived CD36+ GPA- cells were induced to form erythroid colonies with IL-3 alone. Conversely, FK228 inhibited the generation of CD36+ GPAhigh relatively mature erythroid cells from CD34+ cells in the presence of erythropoietin (EPO) and SCF + EPO. FK228 suppressed the EPO-mediated survival of CD36+ GPAlow/- and CD36+ GPAhigh cells and induced their apoptosis. Similar effects were observed for trichostatin A in the generation of erythroid cells in IL-3- and EPO-containing cultures. These data suggest that HDACs negatively regulate the IL-3-mediated growth of early erythroid precursors by suppressing their responsiveness to IL-3, while playing an important role in EPO-mediated differentiation and survival of erythroid precursors. Our data revealed that HDACs have diverse functions in human adult erythropoiesis.

The regulatory role of Hyper-IL-6 in the differentiation of myeloid and erythroid progenitors derived from human cord blood.

This study was designed to investigate the regulatory role of soluble interleukin-6 receptor (sIL-6R) and interleukin-6 (IL-6) fusion protein (Hyper-IL-6) in the differentiation of human myeloid and erythroid progenitors by a serum-free liquid suspension culture system, using the human cord blood-derived CD34(+)CD38(-) cells as a target. We found that Hyper-IL-6 promoted the generation of CD15(+) granulocytic and CD14(+) monocytic cells and suppressed that of CD14(-)CD1a(+) dendritic cells from CD36(-)CD15(-)CD14(-)CD1a(-)IL-6R(+) myeloid progenitors. Conversely, CD34(+)CD38(-) cell-derived early erythroid progenitors were negative for IL-6R expression. Hyper-IL-6 potentiated the generation of CD36(+)glycophorinA(high) mature erythroid cells from the IL-6R(-) early erythroid progenitors. Our results indicate that Hyper-IL-6 augments the generation of CD15(+) granulocytic, CD14(+) monocytic and CD36(+)glycophorinA(high) cell and suppresses that of CD14(-)CD1a(+) dendritic cells.

Oral Xeloda plus bi-platinu two-way combined chemotherapy in treatment of advanced gastrointestinal malignancies.

AIM: To compare the effect, adverse events, cost-effectiveness and dose intensity (DI) of oral Xeloda vs calcium folinate (CF)/5-FU combination chemotherapy in patients with advanced gastrointestinal malignancies, both combined with bi-platinu two-way chemotherapy. METHODS: A total of 131 patients were enrolled and randomly selected to receive either oral Xeloda (X group) or CF/5-FU (control group). Oral Xeloda 1,000 mg/m2 was administered twice daily from d 1 to 14 in X group, while CF 200 mg/m2 was taken as a 2-h intravenous infusion followed by 5-FU 600 mg/m2 intravenously for 4-6 h on d 1-5 in control group. Cisplatin and oxaliplatin were administered in the same way to both the groups: cisplatin 60-80 mg/m2 by hyperthermic intraperitoneal administration, and oxaliplatin 130 mg/m2 intravenously for 2 h on d 1. All the drugs were recycled every 21 d, with at least two cycles. Pyridoxine 50 mg was given t.i.d. orally for prophylaxis of the hand-foot syndrome (HFS). Then the effect, adverse events, cost-effectiveness and DI of the two groups were evaluated. RESULTS: Hundred and fourteen cases (87.0%) finished more than two chemotherapy cycles. The overall response rate of them was 52.5% (X group) and 42.4% (control group) respectively. Tumor progression time (TTP) was 7.35 mo vs 5.95 mo, and 1-year survival rate was 53.1% vs 44.5%. There was a remarkable statistical significance of TTP and 1-year survival between the two groups. The main Xeloda-related adverse events were myelosuppression, gastrointestinal toxicity, neurotoxicity and HFS, which were mild and well tolerable. Therefore, no patients withdrew from the study due to side effects before two chemotherapy cycles were finished. Both groups finished pre-arranged DI and the relative DI was nearly 1.0. The average cost for 1 patient in one cycle was RMB9 137.35 (X group) and RMB8 961.72 (control group), or USD1 100.89 in X group and USD1 079.73 in control group. To add 1% to the response rate costs RMB161.44 vs RMB210.37 respectively (USD19.45 vs USD25.35). One-month prolongation of TTP costs RMB1 243.18 vs RMB1 506.17 (USD149.78 vs USD181.47). Escalation of 1% of 1-year survival costs RMB172.74 vs RMB201.64 (USD20.75 vs USD24.29). CONCLUSION: Oral Xeloda combined with bi-platinu two-way combination chemotherapy is efficient and tolerable for patients with advanced gastrointestinal malignancies; meanwhile the expenditure is similar to that of CF/5-FU combined with bi-platinu chemotherapy, and will be cheaper if we are concerned about the increase of the response rate, TTP or 1-year-survival rate pharmacoeconomically.

Oral attenuated Salmonella typhimurium vaccine against MG7-Ag mimotope of gastric cancer.

AIM: To develop an oral attenuated Salmonella typhimurium vaccine against gastric cancer and to evaluate its efficacy in mice. METHODS: A complementary sequence of Nco I site and a sequence coding for MG7-Ag mimotope were designed at the 5' terminus of forward primer. Using p1.2 II-HBCAg plasmid as template, PCR was performed to get a fusion gene of the mimotope and a HBcAg gene. The fusion gene was then subcloned into the plasmid pYA3341 complementary to Salmonella typhimurium X4550, and the recombinant plasmid was then transformed into attenuated Salmonella typhimurium X4550. Balb/c mice were orally immunized with the recombinant Salmonella typhimurium X4550. The mice were immunized every 2 wk to reinforce the immunity. At the 6th wk, serum titer of antibody was detected by ELISA, and at the 8th wk, cellular immunity was detected by (51)Cr release test. Ehrlich ascites carcinoma cells expressing MG7-Ag were used in tumor challenge assay as a model to evaluate the protective effect of the vaccine. RESULTS: Serum titer of antibody against MG7-Ag was significantly higher in mice immunized with the vaccine than in control groups (0.9538+/-0.043 vs 0.6531+/-0.018, P<0.01; 0.9538+/-0.043 vs 0.6915+/-0.012, P<0.01), while in vitro (51)Cr release assay of the splenocytes showed no statistical difference in the three groups. Two weeks after tumor challenge, 1 in 5 immunized mice was tumor free, while all the mice in the control group presented tumor. CONCLUSION: Oral attenuated Salmonella typhimurium vaccine against the MG7-Ag mimotope of gastric cancer is immunogenic. It can induce significant humoral immunity against tumors in mice, and has some protective effects.

Development of an oral DNA vaccine against MG7-Ag of gastric cancer using attenuated salmonella typhimurium as carrier.

AIM: To develop an oral DNA vaccine against gastric cancer and evaluate its efficacy in mice. METHODS: The genes of the MG7-Ag mimotope and a universal Th epitope (Pan-DR epitope, PADRE) were included in the PCR primers. By PCR, the fusion gene of the two epitopes was amplified. The fusion gene was confirmed by sequencing and was then cloned into pcDNA3.1(+) plasmid. The pcDNA3.1 (+)-MG7/PADRE was used to transfect an attenuated Salmonella typhimurium. C57BL/6 mice were orally immunized with 1X10(8) cfu Salmonella transfectants. Salmonella harboring the empty pcDNA3.1(+) plasmid and phosphate buffer saline (PBS) were used as negative controls. At the 6th week, serum titer of MG7-Ag specific antibody was detected by ELISA. At the 8th week cellular immunity was detected by an unprimed proliferation test of the spleenocytes by using a ((3)H)-thymidine incorporation assay. Ehrlich ascites carcinoma cells expressing MG7-Ag were used as a model in tumor challenge assay to evaluate the protective effect of the vaccine. RESULTS: Serum titer of antibody against MG7-Ag was significantly higher in mice immunized with the vaccine than that in control groups (0.841 vs 0.347, P<0.01; 0.841 vs 0.298, P<0.01), while in vitro unprimed proliferation assay of the spleenocytes showed no statistical difference between those three groups. Two weeks after tumor challenge, 2 in 7 immunized mice were tumor free, while all the mice in the control groups showed tumor formation. CONCLUSION: Oral DNA vaccine against the MG7-Ag momitope of gastric cancer is immunogenic. It can induce significant humoral immunity against tumor in mice, and the vaccine has partially protective effects.

[Screening of bioactive peptide that mimic the epitope of gastric cancer associated antigen].

AIM: To screen bioactive peptides that mimic the epitope of gastric cancer associated antigen. METHODS: Anti-gastric cancer monoclonal antibody (mAb) MG7 was purified by ion chromatography, and then coated on ELISA plate. By using the mAb as selective molecular, a 12-meres phage displaying peptide library was biopanned, and the positive clones were selected. RESULTS: 12 positive phage clones were selected. CONCLUSION: A candidate mimic epitope of gastric cancer associated antigen was identified, which provided the foundation for developing tumor peptide vaccine.

[Development of oral DNA vaccine based on MG(7)-Ag mimotope of gastric cancer].

OBJECTIVE: To develop an oral DNA vaccine based on MG(7)-Ag mimotope of gastric cancer using attenuated Salmonella typhimurium and evaluate its efficacy and protective effect. METHODS: The eukaryotic expression vector including the MG(7)-Ag mimotope and a Th epitope was constructed, and then transduced into an attenuated Salmonella typhimurium to get the oral DNA vaccine. C57BL/6 J mice were orally immunized with 1 x 10(8) cfu Salmonella transfectants, with Salmonella harboring empty plasmid, with phophate buffered saline (PBS) as control. At the 6th week, serum titer of MG(7) antibody was detected by ELISA. In the 8th week, a [(3)H]-thymidine incorporation assay was performed to test the proliferation of murine spleen cells to the stimulant of MG(7)-Ag mimicry peptide. At the same time, Ehrlich ascites carcinoma cells expressing MG(7)-Ag were used in tumor challenge assay to evaluate the protective effect of the immunization. RESULTS: The oral DNA vaccine induced MG(7) antibody in mice, while in vivo unprimed proliferation assay of the spleenocytes showed no difference among the three groups. Two weeks after tumor challenge, 2 in 7 immunized mice were tumor free, while none in the control group was protected. CONCLUSION: Oral DNA vaccine based on the MG(7)-Ag momitope is immunogenic. It is able to induce specific immunity response against tumor in mice, and the vaccine is partially protective.

Expression and bioactivity identification of soluble MG7 scFv.

AIM: To examine the molecular mass and identify the bioactivity of MG7 scFv for its application as a targeting mediator in gene therapy of gastric cancer. METHODS: Two strongly positive recombinant phage clones screened from MG7 recombinant phage antibody library were separately transfected into E.coli TG1. Plasmid was isolated from the transfected E.coli TG1 and digested by EcoR I and Hind III to examine the length of exogenous scFv gene. Then, the positive recombinant phage clones were individually transfected into E.coli HB2151. The transfectant was cultured and induced by IPTG. Perplasmic extracts was prepared from the induced transfectant by osmotic shock. ELISA was used to examine the antigen-binding affinity of the soluble MG7 scFv. Immunodotting assay was adopted to evaluate the yield of soluble MG7 scFv produced by transfected E.coli HB2151. Western blot was used to examine the molecular mass of MG7 scFv. Finally, the nucleotide sequence of MG7 scFv was examined by DNA sequencing. RESULTS: Two positive recombinant phage clones were found to contain the exogenous scFv gene. ELISA showed that MG7 scFv had strong antigen-binding affinity. Immuodotting assay showed that transfected E.coli HB2151 could successfully produce the soluble MG7 scFv with high yield via induction by IPTG. The molecular mass of MG7 scFv was 30 kDa by western blot. DNA sequencing demonstrated that the VH and VL genes of MG7 scFv were 363 bp and 321 bp,respectively. CONCLUSION: We have successfully developed the soluble MG7 scFv which possessed strong antigen-binding affinity.

Down-regulation of Hsp90 could change cell cycle distribution and increase drug sensitivity of tumor cells.

AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.METHODS:A 1.03kb cDNA sequence of Hsp90beta was obtained from the primary plasmid phHSP90 by EcoR I and BamH I nuclease digestion and was cloned to the EcoR I and BamH I site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90beta expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protection assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.RESULTS:In EcoR I and BamH I restriction analysis, the size and the direction of the cloned sequence of Hsp90beta remained what had been designed and the gene constructs were named pcDNA-Hsp90.AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G(1) phase cells were increased; S phase and G(2) phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G(1)phase cells were decreased, G(2) phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G(1), S and G(2) phase cells remained unchanged as compared with their parental cell lines. The sensitivity of AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P < 0.05).CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.