Irradiated VEGF164-modified tumor cell vaccine protected mice from the parental tumor challenge.

Vascular endothelial growth factor (VEGF) is an important regulating molecule of angiogenesis in tumor formation and progression. Cancer cells always secrete VEGF to stimulate angiogenesis that facilitate growth and invasion of the tumor. In this study, we established a VEGF164 overexpressing LL/2 lung cancer cell model and found that the postirradiated VEGF164-modified tumor cells protected the host against the challenge with LL/2 wild-type tumor cells. Histochemical assay showed that there were large areas of tumor necrosis with macrophage infiltration in the mice vaccinated with the VEGF164-modified tumor vaccine. T-cells isolated from the vaccinated mice showed cytotoxicity against the parental tumor cells in a dose-dependent manner. Meanwhile, sera from the mice vaccinated with LL/2-VEGF164 showed higher titers of antibodies against parental tumor cells compared with the nonvaccinated groups. Our results indicated that VEGF164-modified tumor vaccine could modulate host antitumor immune response and hold therapeutic potential for cancer.

Low-dose paclitaxel improves the therapeutic efficacy of recombinant adenovirus encoding CCL21 chemokine against murine cancer.

Secondary lymphoid tissue chemokine (SLC/CCL21), one of the CC chemokines, exerts potent antitumor immunity by co-localizing T cells and dendritic cells at the tumor site and is currently tested against human solid tumors. Here, we investigated whether the combination of recombinant adenovirus encoding murine CCL21 (Ad-mCCL21) with low-dose paclitaxel would improve therapeutic efficacy against murine cancer. Immunocompetent mice bearing B16-F10 melanoma or 4T1 breast carcinoma were treated with either Ad-mCCL21, paclitaxel, or both agents together. Our results showed that Ad-mCCL21 + low-dose paclitaxel more effectively reduced the growth of tumors as compared with either treatment alone and significantly prolonged survival time of the tumor-bearing animals. These antitumor effects of the combined therapy were linked to altered cytokine network at the tumor site, enhanced apoptosis of tumor cells, and decreased formation of new vessels in tumors. Importantly, the combined therapy elicited a strong therapeutic antitumor immunity, which could be partly abrogated by the depletion of CD4(+) or CD8(+) T lymphocytes. Collectively, these preclinical evaluations may provide a combined strategy for antitumor immunity and should be considered for testing in clinical trials.

VEGF-D-induced draining lymphatic enlargement and tumor lymphangiogenesis promote lymph node metastasis in a xenograft model of ovarian carcinoma.

BACKGROUND: Vascular endothelial growth factor (VEGF)-D has been shown to promote lymph node metastasis in several cancers. Although generally overexpressed in ovarian carcinoma, its role in nodal dissemination of this cancer is unclear. To clarify the role of VEGF-D and the underlying molecular mechanisms, we investigated the function of VEGF-D using a mouse xenograft model of ovarian cancer. METHODS: Human ovarian serous adenocarcinoma SKOV3 cells were transfected with VEGF-D recombinant plasmid DNA, or with control vectors. The cells were injected subcutaneously into the footpads of nude mice. Tumor growth was evaluated weekly. Draining lymphatics were observed grossly with Evan's blue lymphangiography. Tumoral lymphatics were delineated with both Evan's blue and LYVE-1 immunostaining. Tumor metastases to lymph nodes were evaluated by H&E and CA125/CD40 staining. Expression of VEGF-D in primary tumors and levels of CA125 in involved lymph nodes were examined by immunohistochemistry. Tumor cell apoptosis was analyzed by Hoechst dyeing. RESULTS: Mice bearing VEGF-D overexpressing xenografts showed a significantly higher rate of lymph node metastasis and markedly greater tumor volume compared with the controls. The functional lymphatic vessels were denser and enlarged in marginal and central tumor portions. Additionally, higher CA125 expression was observed in the involved lymph nodes. Mice bearing VEGF-D overexpressing xenografts also exhibited a markedly lower apoptotic index compared with the controls. CONCLUSIONS: Our data demonstrate the important role of VEGF-D in promoting lymph node metastasis by increasing tumor lymphangiogenesis, stimulating draining lymphatic vessel formation, and enhancing tumor invasiveness. Our findings show that VEGF-D can be a promising therapeutic target for ovarian cancer.

[Relationship between miR-218 and CDK6 expression and their biological impact on glioma cell proliferation and apoptosis].

OBJECTIVES: To investigate the relationship between the expression of miR-218 and CDK6 in glioma cells, and their biological impacts on the tumor cell proliferation and apoptosis. METHODS: Expression levels of miR-218 as well as CDK6 and Ki-67 proteins were analyzed in 60 cases of gliomas with various grades and 10 control brain tissue samples by tissue microarray, locked oligonucleotide probe in situ hybridization and immunohistochemistry. Glioblastoma multiform cell line (U87MG) was transfected with miR-218 mimics (mimics group) and a control sequence (control group), followed by qRT-PCR detection of miR-218 and immunocytochemical stain of CDK6 and Ki-67, respectively. Single cell gel electrophoresis was used to detect the presence of apoptotic cell. RESULTS: The miR-218 labeling indexes (LI) were statistically different (P<0.05) among all groups including control (22.45 +/- 0.59) and various glioma groups (grades I - II 4.00 +/- 1.07, grade III 1.87 +/- 1.06 and grade IV 0.94 +/- 0.78, respectively). The CDK6 LI of the four groups was 7.25 +/- 1.20, 16.71 +/- 0.80, 24.43 +/- 0.62 and 32.05 +/- 0.43, respectively. Significant differences existed between the control group and the glioma groups, and between grade IV and grades I - II glioma groups (P<0.01). Ki-67 positive cell densities of the above four groups (0.00 +/- 0.00, 9.30 +/- 3.48, 31.15 +/- 9.44 and 60.15 +/- 13.60) were significantly different from one and another (P<0.01). The expression of miR-218 negatively correlated with CDK-6 LI (r = -0.480, P<0. 01) and Ki-67 positive cell density (r = - 0.534, P<0.01), while the latter two positively correlated with each other (r = 0.530, P<0.01). U87MG transfection experiment showed that the miR-218 level of the mimics group was significantly higher than that of the control group (P<0.01). CDK6 and Ki-67 LI of the mimics group (14.74 +/- 1.19 and 30.88 +/- 3.31) were significantly lower than those of the control group (79.06 +/- 2.07 and 64.94 +/- 3.96, P<0.01), whilst its apoptotic index (AI) (68.44 +/- 7.05) was significantly higher than that of the control group (13.04 +/- 0.97, P<0.01). CONCLUSIONS: The expression level of miR-218 is an important reference indicator for the assessment of the grade of gliomas. An aberrant decrease of its expression may lead to an increase of the CDK6 expression and proliferative activity of giloma cells. Introducing exogenous miR-218 may effectively down-regulate the CDK6 expression, inhibit cell proliferation and induce apoptosis of malignant giloma cells. These findings imply that miR-218 may serve as a therapeutic agent against malignant glioma.

[Antitumor effects of matrix protein of vesicular stomatic virus on EL4 lymphoma mice].

OBJECTIVE: To explore antitumor effects of plasmid pcDNA3. 1-MP encoding matrix protein of vesicular stomatitis virus (VSV) complexed with cationic liposome (DOTAP:CHOL) in mice with EL4 lymphoma. METHODS: C57BL/6 mouse model with EL4 lymphoma was established. Sixty mice bearing EL4 lymphoma were divided randomly into five groups including Lip-MP, Lip-pVAX, Lip, ADM and NS groups, which were intravenously injected with liposome-pcDNA 3. 1-MP complex, liposome-pVAX complex, empty liposome, Adriamycin and normal saline respectively every three days. Tumor volumes and survival time were monitored. Microvessel density and tumor proliferative index in tumor tissues were determined by CD31, Ki-67 immunohistochemistry staining, meanwhile the tumor apoptosis index was measured by TUNEL method. RESULTS: From 6 days after treatments on, the tumor volume in Lip-MP group was much smaller than that in Lip-pVAX, Lip and NS group (P < 0.05). The median survival time of mice in Lip-MP group, 44 days after inoculation of tumor cells, was significantly higher than that in other groups (P < 0.05), which was 39 days, 38.5 days and 34 days in Lip-pVAX, Lip and NS groups respectively. The MVD value in tumor tissues in Lip-MP group was less than that in Lip-pVAX, Lip and NS groups (P < 0.05). Ki67 staining revealed that Lip-MP complex apparently suppressed the proliferation of EL4 tumor cells in vivo (P < 0.05). TUNEL assays showed that apoptosis index of tumor cells in Lip-MP group, 10.60 +/- 1.71, was much higher than that in other three groups (P < 0.05). CONCLUSIONS: Lip-MP complex, the plasmid encoding matrix protein of VSV (VSV-MP) encapsulated in cationic liposome, significantly inhibited the growth of tumor and prolonged the survival of mice bearing EL4 lymphoma, which may be related to the induction of tumor cell apoptosis, inhibition of tumor angiogenesis, and suppression of tumor cell proliferation.

Combination of vesicular stomatitis virus matrix protein gene therapy with low-dose cisplatin improves therapeutic efficacy against murine melonoma.

Vesicular stomatitis virus (VSV) matrix protein (MP) can directly induce apoptosis via the mitochondrial pathway due to the inhibition of host gene expression. Our previous studies have demonstrated that MP gene therapy efficiently suppressed the growth of malignant tumor in vitro and in vivo. The present study was designed to determine the possibility that the combination of MP gene therapy with low-dose cisplatin would improve therapeutic efficacy against murine melanoma. Immunocompetent C57BL/6 mice bearing B16-F10 melanoma were established. Mice were treated once every 5 days with i.v. administration of 10 microg pVAX-MP/30 microg liposome complex per mouse for 16 days and i.p. delivery of cisplatin at 4 mg/kg/mouse on days 6 and 12 after the initiation of MP treatment. We found that MP + cisplatin treatment resulted in significant inhibition of tumor growth and improved the survival time of melanoma-bearing mice. MP successfully inhibited angiogenesis as assessed by CD31. Histological examination revealed that the combination therapy led to significant increased induction of apoptosis, tumor necrosis, and elevated CD8(+) lymphocyte infiltration. Furthermore, the induction efficacy of the CTL response was dramatically enhanced by the combination therapy. Our findings may prove useful in further explorations of the application of these combinational approaches to the treatment of malignant melanoma.

A novel transdermal plasmid-dimethylsulfoxide delivery technique for treatment of psoriasis.

BACKGROUND: Psoriasis is a chronic and relapsing inflammatory skin disease associated with various immunologic abnormalities. Repeated subcutaneous injection of interleukin-4 (IL-4) has been established as an effective treatment to counteract psoriasis. OBJECTIVE: We investigated whether gene therapy using IL-4 expression plasmid (pIL-4) via transdermal delivery was an alternative treatment for psoriasis. In our experiment, dimethylsulfoxide (DMSO) was used as a penetration enhancer. METHODS: At first, the penetration efficiency of the complex of reporter plasmid accompanied by DMSO was investigated both in vitro and in vivo. Then, the antipsoriasis efficiency of the treatment with pIL-4-DMSO was tested in mice. RESULTS: The expression of the reporter gene was detected in epidermis and dermis both in vitro and in vivo. More importantly, the psoriasis symptoms were relieved, and significant reductions in some psoriasis-associated factors were observed after pIL-4-DMSO treatment. CONCLUSION: We conclude that the topical application of pIL-4-DMSO can treat psoriasis to a significant extent.

[Construction of recombinant adenovirus carrying HBx and mIL-12].

OBJECTIVE: To construct a recombinant adenovirus Ad-HBx-mlL-12 carrying HBx and mIL-12. METHODS: HBx and mIL-12 were cloned into the shuttle plasmid pAdenoVator-CMV5 and confirmed by means of enzymatic manipulation. After linearization by EcoR I digestion, the recombinant shuttle plasmid pAdV-HBx-mIL-12 was transformed into competent BJ5183 germs with the adenoviral backbone plasmid pAdenoVator deltaE1/E3 and then homologically recombined to obtain the recombinant adenovirus plasmid. After confirmation, the recombinant adenovirus plasmid pAd-HBx-mIL-12 was linearized with Pac I digestion and transfected into 293 cells via liposome, and then adenovirus package and amplification were performed. RESULTS: It was confirmed that the recombinant adenovirus Ad-HBx-mIL-12 had been successfully constructed and both HBx and mIL-12 were expressed in 293 cells. CONCLUSION: The recombinant adenovirus carrying HBx and mIL-12 has been successfully constructed, which lays a foundation for the further study of antitumor mechanism and gene therapy.

A promising cancer gene therapy agent based on the matrix protein of vesicular stomatitis virus.

The matrix (M) protein of vesicular stomatitis virus (VSV) plays a key role in inducing cell apoptosis during infection. To investigate whether M protein-mediated apoptosis could be used in cancer therapy, its cDNA was amplified and cloned into eukaryotic expression vector pcDNA3.1(+). The recombinant plasmid or the control empty plasmid pcDNA3.1(+) was mixed with cationic liposome and introduced into various tumor cell lines in vitro, including lung cancer cell LLC, A549, colon cancer cell CT26 and fibrosarcoma cell MethA. Our data showed that the M protein induced remarkable apoptosis of cancer cells in vitro compared with controls. Fifty micrograms of plasmid in a complex with 250 microg cationic liposome was injected intratumorally into mice bearing LLC or MethA tumor model every 3 days for 6 times. It was found that the tumors treated with M protein plasmid grew much more slowly, and the survival of the mice was significantly prolonged compared with the mice treated with the control plasmid. In MethA fibrosarcoma, the tumors treated with M protein plasmid were even completely regressed, and the mice acquired longtime protection against the same tumor cell in rechallenge experiments. Both apoptotic cells and CD8(+) T cells were widely distributed in M protein plasmid-treated tumor tissue. Activated cytotoxic T lymphocytes (CTLs) were further detected by means of (51)Cr release assay in the spleen of the treated mice. These results showed that M protein of VSV can act as both apoptosis inducer and immune response initiator, which may account for its extraordinary antitumor effect and warrant its further development in cancer gene therapy.

Humoral immunity responses against EGFR-positive tumor cells induced by xenogeneic EGFR expressed in the yeast Pichia pastoris.

The breaking of immune tolerance against self epidermal growth factor receptor (EGFR) should be a promising approach for the treatment of those receptor-positive tumors. We have previously shown that human EGFR as a xenoantigen induced a specific antitumor activity against EGFR-positive mouse tumors. Our further studies demonstrated that a recombinant form of extracellular domain of mouse EGFR provoked active cellular immunity responses against EGFR-positive human tumors. In this study, we investigated whether the recombinant murine EGFR expressed in the yeast Pichia pastoris would induce humoral immunity responses against EGFR-positive human tumors. To test this concept, polyclonal immunoglobulin (IgG), which was produced by vaccinating the rabbits with the recombinant mEGFR, was purified from the sera of the rabbits. We evaluated the antitumor activity of the polyclonal IgG in the nude mice bearing A431 tumors. Mice were i.v. treated with the purified IgG at 100 mg/kg 1 day before the mice were inoculated with the tumor cells and then twice per week for 4 weeks. Our results showed that the polyclonal IgG would efficiently inhibit the growth of the solid tumor in vivo. The antitumor effect of the polyclonal IgG may result from the increasing rate of apoptosis and induction of differentiation of the tumor cells in vivo. The present findings may provide insight into treatment of EGFR-positive tumors through induction of the humoral immunity responses based on xenogeneic homologous EGFR.

[Antitumor and antimetastatic activities of plasmid pcDNA3. 1-IP10 complexed with cationic liposome in mice with 4T1 breast cancer].

OBJECTIVE: To determine the antitumor and antimetastatic effects of plasmid pcDNA3. 1-IP10 complexed with cationic liposome (DOTAP:CHOL) in mice with 4T1 breast cancer. METHODS: BALB/c mice model with 4T1 breast cancer was established. Thirty six mice with 4T1 breast cancers were divided randomly into three groups, which were intravenously injected with normal saline (200 microL), Lip-null (50 microg DNA, 200 microL) and Lip-IP10 (50 microg DNA, 200 microL) respectively every five days for six doses. The size of the tumors, the number of lung metastasis noduls and survival time were measured. Four mice from each group were sacrificed 43 days after tumor implantation. The tumor microvascula densities (MVD) were detected by immunohistochemical staining. RESULTS: Lip-IP10 inhibited the growth of tumor and the formation of lung metastasis neoplasm (P < 0.05). The Lip-IP10 group had a median of 3 lung metastasis nodules, less than the NS group (45) and Lip-null group (40) (P < 0.05). Lip-IP10 significantly prolonged the survival time of the tumor-bearing mice (P < 0.05). The histomorphometric analysis revealed a decreased MVD in the Lip-IP10 group (21.50 +/- 15.41 vs. 44.25 +/- 5.51 for the NS group and 43.45 +/- 4.21 for the Lip-null group, P < 0.05). CONCLUSION: IP10 encapsulated in cationic liposome inhibits the growths and metastases of 4T1 breast cancers, which is based on the mechanism of IP10 inhibiting tumor angiogenesis.

[Apoptosis of colon carcinoma cells of mice induced by vesicular stomatitis virus matrix protein in vitro].

OBJECTIVE: To test the inhibitive effect of the matrix protein of vesicular stomatitis virus (VSV) on the proliferation of colon carcinoma cells of mice in vitro. METHODS: The plasmid pcDNA3. 1-M encoding M protein of vesicular stomatitis viruses was transfected with lipofectamine 2000 into the colon carcinoma (CT26) cells of mice. The expression of VSV-M protein in the CT26 cells was detected by Western blot. The effect of vesicular stomatitis virus (VSV) matrix protein on the proliferation and apoptosis of colon carcinoma cells was measured by MTT, PI stainning and flow cytometry. RESULTS: The plasmid expressed M protein in the CT26 cells. Cytopathic effect was shown in the CT26 cells with transfected pcDNA3.1-M. The proliferation of the CT26 cells was suppressed significantly in vitro (76.4%, P < 0.05). The M protein induced apoptosis of the CT26 cells (80.2%), which was higher than'that of the controls (P < 0.05). CONCLUSION: The eukaryotic expression plasmid pcDNA3.1-M encoding M protein of vesicular stomatitis viruses induces apoptosis of CT26 cells, which has implications on the treatment of human colon cancer.

[Inhibition of tumour cells with hepatitis B virus x (HBx) gene adenoviral vector in vivo].

OBJECTIVE: To investigate the inhibitory effects of the hepatitis B virus x protein (HBx protein) on tumor in vivo. METHODS: H22 cells were infected with Ad-eGFP to detect infection efficiency of adenovirus. The BALB/c mouse model of malignant ascites was established by implanting H22 cell intraperitoneally into the animal, Ad-HBx, Ad-null or NS were administered intraperitoneally in BALB/c mice separately to detect HBx expression in H22 cells and effects of HBx on inhibition on proliferation of H22 cells. RESULTS: High efficiency of Ad in infecting H22 cells in vitro was observed. HBx protein was expressed in H22 cells after intraperitoneal injection of Ad-HBx. The effect of Ad-HBx on inhibition of the peritoneal capillary permeability and the ascites accumulation (P<0.05); on reduction of the number of red cells and tumor cells counted in malignant ascites (P<0.05), and on inhibition of tumor cell life cycle (the G2/M arrest) in malignant ascites were identified by flow cytometric analysis. CONCLUSION: HBx protein can be expressed in tumour cells and can inhibit the proliferation of tumour cells in vivo, and this might be a new potential treatment for malignant ascites.

Human alpha-defensin-1 inhibits growth of human lung adenocarcinoma xenograft in nude mice.

Human alpha-defensin-1 (HNP1), a small antimicrobial peptide, shows cytotoxicity to tumor cells in vitro and inhibitory activity for pathologic neovascularization in vivo. Here, we did a gene therapy with a plasmid that expresses a secretable form of HNP1 for assaying its antitumor activity. The expression and secretion of HNP1 were determined by reverse transcription-PCR and ELISA in vitro. We found that expression of HNP1 in A549 tumor cells caused significant growth inhibition. This effect is most likely cell autonomous, as a significant amount of recombinant HNP1 protein was found to be accumulated in the cytoplasm by immunohistochemical staining using an anti-HNP1 antibody and the supernatant containing secreted HNP1 failed to produce any noticeable antitumor activity. Flow cytometry and Hoechst 33258 staining showed that the number of apoptotic cells among the A549 cells expressing recombinant HNP1 proteins was significantly greater than that of the nontransfected control cultures, suggesting that this growth-inhibitory activity was due to an apoptotic mechanism triggered by the intracellular HNP1. The antitumor activity of intracellularly expressed HNP1 was also shown in vivo. Decreased microvessel density and increased lymphocyte infiltration were observed in tumor tissue from HNP1-treated mice through histologic analysis. These results indicate that intracellularly expressed HNP1 induces tumor cell apoptosis, which inhibits tumor growth. The antiangiogenesis effect of HNP1 may contribute to its inhibitory activity in vivo, and HNP1 might involve the host immune response to tumor. These findings provide a rationale for developing HNP1-based gene therapy for cancer.

Vesicular stomatitis virus matrix protein gene enhances the antitumor effects of radiation via induction of apoptosis.

Vesicular stomatitis virus (VSV) matrix (M) protein can directly induce apoptosis by inhibiting host gene expression when it is expressed in the absence of other viral components. Previously, we found that the M protein gene complexed to DOTAP-cholesterol liposome (Lip-MP) can suppress malignant tumor growth in vitro and in vivo; however, little is known regarding the biological effect of Lip-MP combined with radiation. The present study was designed to determine whether Lip-MP could enhance the antitumor activity of radiation. LLC cells treated with a combination of Lip-MP and radiation displayed apparently increased apoptosis compared with those treated with Lip-MP or radiation alone. Mice bearing LLC or Meth A tumors were treated with intratumoral or intravenous injections of Lip-MP and radiation. The combined treatment significantly reduced mean tumor volumes compared with either treatment alone in both tumor models and prolonged the survival time in Meth A tumor models and the intravenous injection group of LLC tumor models. Moreover, the antitumor effects of Lip-MP combined with radiation were greater than their additive effects when compared with the expected effects of the combined treatment in vivo. This study suggests that Lip-MP enhanced the antitumor activity of radiation by increasing the induction of apoptosis.

Immunity against tumor angiogenesis induced by a fusion vaccine with murine beta-defensin 2 and mFlk-1.

PURPOSE: Previous studies indicated that humoral or cellular immunity against murine vascular endothelial growth factor 2 (mFlk-1) was elicited to inhibit tumor growth. Here we describe a genetic fusion vaccine, pMBD2-mFlk-1, based on the targeting of a modified mFlk-1 to antigen-presenting cells by a murine beta-defensin 2 (MBD2) protein to induce both humoral and cellular immunity against mFlk-1, with the targeting especially focused on immature dendritic cells. EXPERIMENTAL DESIGN: The protective and therapeutic antitumor immunity of the fusion vaccine was investigated in mouse models. Antiangiogenesis effect was detected by immunohistochemical staining and alginate-encapsulate tumor cell assay. The mechanisms of the fusion vaccine were primarily explored by detection of autoantibodies and CTL activity and confirmed by the deletion of immune cell subsets. RESULTS: The fusion vaccine elicited a strong protective and therapeutic antitumor immunity through antiangiogenesis in mouse models, and this worked through stimulation of an antigen-specific CD8+ T-cell response as well as a specific B-cell response against mFlk-1. The findings were confirmed by depletion of immune cell subsets and in knockout mice. CONCLUSION: Our study showed that a fusion vaccine based on self immune peptide (MBD2) and self antigen (mFlk-1) induced autoimmunity against endothelial cells, resulting in inhibition of tumor growth, and could be further exploited in clinical applications of cancer immunotherapy.

[Enhanced expression of human vimentin intermediate filaments in hepatocellular carcinoma cells decreases their proliferative and invasive abilities in vitro].

OBJECTIVE: Expression of vimentin in carcinoma cells is a marker for poor prognosis in patients. The aim of this investigation was to assess the influence of vimentin on the characteristics of carcinoma cells. METHODS: The full-length vimentin gene open reading frame (1401 base pairs) was cloned into the plasmid vector pcDNA 3.1 (+), and these vectors were used to stably transfect the human hepatocellular carcinoma HepG2 cell line. Vimentin gene expression was evaluated by RT-PCR and Western blot. Proliferative activity and invasive potential of tumor cells were determined by the CellTiter 96 aqueous one solution cell proliferation assay and BioCoat GFR Matrigel invasion chamber, respectively. RESULTS: DNA sequencing and restriction endonuclease digestion analysis demonstrated that the recombinant vector was correctly cloned. The stable cell line demonstrated a higher vimentin RNA and protein expression. However, both proliferative and invasive abilities of the cells were reduced in vitro ( P < 0.05). CONCLUSION: A recombinant plasmid pcDNA3. 1-VIM is successfully constructed and a carcinoma cell line HepG2-pV highly expressing vimentin is obtained. Recombinant vimentin protein suppresses the proliferative and invasive abilities of HepG2 cells, suggesting that it might decrease malignant phenotype of tumor cells in vitro. This work makes a foundation for further study on the relationship between vimentin and biological phenotype of carcinoma cells.

[Research on construction and expression of recombinant eukaryotic expression plasmid for mouse adiponectin].

OBJECTIVE: To construct the recombinant eukaryotic expression plasmid for mouse adiponectin so as to supply experimental basis for research further on the function of adiponectin. METHODS: Extracting the total RNA from mouse adipose tissue, applying RT-PCR to amplify the complete coding region of mouse adiponectin cDNA and connecting the amplified product with pCDNA3.1(+) vector; then verifying the recombinant plasmid by sequencing and detecting in vitro recombinant expression and cellular proliferation depression to mouse breast cancer cell 4T1. RESULTS: A 744 bp fragment was got after PCR amplification with the recombinant plasmid, which was confirmed by sequence and expression detected by Western-blot. Besides, compared with the control in vitro test, visible morphological changes of 4T1 cell could be observed after recombinant plasmid cell transfection for 48 h, with cells collapsed or shrunk and cellular proliferation inhibited. During the flow cytometry analysis, the transfected 4T1 cells could also be observed obviously to have a greater proportion of cell apoptosis than the control could be detected. CONCLUSION: The recombinant eukaryotic expression plasmid for mouse adiponectin is successfully constructed, which has an obvious inhibition effect on the proliferation of mouse breast cancer cell 4T1.

Immunotherapy of tumors with protein vaccine based on chicken homologous Tie-2.

PURPOSE: Tie-2 is an endothelium-specific receptor tyrosine kinase known to play a key role in tumor angiogenesis. The present study explores the feasibility of immunotherapy of tumors by using a protein vaccine based on chicken Tie-2 as a model antigen to break the immune tolerance against Tie-2 in a cross-reaction between the xenogeneic homologous and self-Tie-2. EXPERIMENTAL DESIGN AND RESULTS: In this study, a chicken homologous Tie-2 protein vaccine (chTie-2) and a corresponding mouse Tie-2 vaccine as a control were prepared and the antitumor effect of these vaccines was tested in two tumor models (murine B16F10 melanoma and murine H22 hepatoma). Immunotherapy with chTie-2 was found effective in two tumor models. Autoantibodies against mouse Tie-2 were detected in sera of mice immunized with chTie-2 through Western blot analysis and ELISA assay. Anti-Tie-2 antibody-producing B cells were detectable by ELISPOT. Histologic examination revealed that autoantibodies were deposited on the endothelial cells of tumor tissues. Purified immunoglobulins from chTie-2-immunized mice could induce the apoptosis of human umbilical vein endothelial cells in vitro. Importantly, adoptive transfer of purified immunoglobulins led to antitumor effect in vivo; apparently, angiogenesis was significantly inhibited in these tumors. Furthermore, the antitumor activity and production of autoantibodies could be abrogated by depletion of CD4+ T lymphocytes. CONCLUSIONS: Our findings may provide a vaccine strategy for cancer therapy and show the potential utilization of interference with Tie-2 pathway.

Antitumour activity of cationic-liposome-conjugated adenovirus containing the CCL19 [chemokine (C-C motif) ligand 19] gene.

CCL19 [chemokine (C-C motif) ligand 19; also known as MIP-3beta (macrophage inflammatory protein-3beta) or ELC (Epstein-Barr-virus-induced molecule 1 ligand chemokine)], one of the immunostimulatory cytokines, chemoattracts both DCs (dendritic cells) and T-lymphocytes. Adenoviral vector is one of the most used gene delivery vectors for cancer therapy because of its high gene-transfection efficiency. However, its wider application is limited, owing to immune responses that reduce transgene expression and decrease the efficacy of repeated administration. We constructed the recombinant replication deficient adenoviral vectors containing the CCL19 gene (Ad-CCL19) and combined them with PEG-PE [poly(ethylene glycol)-phosphatidylethanolamine]-modified cationic liposomes (Ad-CCL19/PEG-PE) for immunotherapy against murine fibrosarcoma. Although there were hardly any therapeutic differences between Ad-CCL19- and Ad-CCL19/PEG-PE-treated mice that were observed at the second administration, the final results demonstrated that Ad-CCL19/PEG-PE-treated mice survived much longer. The antitumour efficacy may be related to the high level of CCL19 after the final administration and lasting expression of IFN-gamma (interferon-gamma) and IL-12 (interleukin-12) in the Ad-CCL19/PEG-PE-treated group, which were measured by reverse-transcription PCR and ELISA. The results demonstrated that PEG-PE-cationic-liposome-conjugated adenovirus could prolong the expression of the therapeutic gene in vivo and may enhance the antitumour efficacy.