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.

Ovarian cancer treatment with a tumor-targeting and gene expression-controllable lipoplex.

Overexpression of folate receptor alpha (FRα) and high telomerase activity are considered to be the characteristics of ovarian cancers. In this study, we developed FRα-targeted lipoplexes loaded with an hTERT promoter-regulated plasmid that encodes a matrix protein (MP) of the vesicular stomatitis virus, F-LP/pMP(2.5), for application in ovarian cancer treatment. We first characterized the pharmaceutical properties of F-LP/pMP(2.5). The efficient expression of the MP-driven hTERT promoter in SKOV-3 cells was determined after an in-vitro transfection assay, which was significantly increased compared with a non-modified LP/pMP(2.5) group. F-LP/pMP(2.5) treatment significantly inhibited the growth of tumors and extended the survival of mice in a SKOV-3 tumor model compared with other groups. Such an anti-tumor effect was due to the increased expression of MP in tumor tissue, which led to the induction of tumor cell apoptosis, inhibition of tumor cell proliferation and suppression of tumor angiogenesis. Furthermore, a preliminary safety evaluation demonstrated a good safety profile of F-LP/pMP(2.5) as a gene therapy agent. Therefore, FRα-targeted lipoplexes with therapeutic gene expression regulated by an hTERT promoter might be a promising gene therapy agent and a potential translational candidate for the clinical treatment of ovarian 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.

Gene therapy using the human telomerase catalytic subunit gene promoter enables targeting of the therapeutic effects of vesicular stomatitis virus matrix protein against human lung adenocarcinoma.

The catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT), is highly active in immortalized cells and more than 90% of human cancer cells, but is quiescent in the majority of normal somatic cells. Thus, the hTERT promoter has been extensively used in targeted cancer gene therapy. Vesicular stomatitis virus (VSV) matrix protein (MP) induces the apoptosis of tumor cells in the absence of other viral components. In our previous studies, we successfully constructed the pVAX-M plasmid from the pVAX plasmid, which expressed wild-type VSV MP (VSV MP is under the control of the CMV promoter) and demonstrated that pVAX-M efficiently suppresses the growth of malignant tumors via the induction of apoptosis in vitro and in vivo. The present study was designed to construct the plasmid phTERTM (VSV MP is under the control of the hTERT promoter) and investigate whether it had a targeted antitumor effect in nude mice bearing human lung adenocarcinoma. In vitro, A549 human lung adenocarcinoma cells were treated with NS, Lip-null, etoposide, Lip-pVAX-M or Lip-phTERT-M, and examined for cell viability through MTT assays or for apoptosis by flow cytometry and TUNEL assays. In vivo, A549 human lung carcinoma models in nude mice were established. Mice were treated with 10 4-weekly intravenous administrations of NS, Lip-null, etoposide (2 mg/kg), Lip-pVAX-M or Lip-phTERT-M. Subsequently, Lip-phTERT-M was found to be the most efficient inhibitor of tumor growth and inducer of tumor cell apoptosis when compared with the other groups in vivo and in vitro (P<0.05). Notably, immunohistochemical staining showed that Lip-phTERT-M significantly limited the overexpression of VSV MP to the tumor tissues and reduced VSV MP expression in other organs in comparison with Lip-pVAX-M (P<0.05). Therefore, it can be concluded that phTERT-M demonstrates a targeted antitumor effect on A549 human lung adenocarcinoma cells. These observations suggest that phTERT-M gene therapy may be a novel and potent strategy for targeting human lung adenocarcinoma.

[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.

Gene therapy with recombinant adenovirus encoding endostatin encapsulated in cationic liposome in coxsackievirus and adenovirus receptor-deficient colon carcinoma murine models.

Adenovirus (Ad)-based antiangiogenesis gene therapy is a promising approach for cancer treatment. Downregulation or loss of coxsackievirus and adenovirus receptor (CAR) is often detected in various human cancers, which hampers adenoviral gene therapy approaches. Cationic liposome-complexed adenoviral vectors have been proven useful in CAR-deficient cells to enhance therapeutic gene transfer in vivo. Here, we investigated the antitumor effects of recombinant adenovirus encoding endostatin (Ad-hE) encapsulated in cationic liposome (Ad-hE/Lipo) on CAR-deficient CT26 colon carcinoma murine models. In vitro, Ad-hE/Lipo enhanced adenovirus transfection in CAR-deficient cells (CT26), and endostatin gene expression was measured by both qualitative and quantitative detection. In addition, an antibody neutralizing assay indicated that neutralizing serum inhibited naked adenovirus 5 (Ad5) at rather higher dilution than the complexes of Ad5 and cationic liposomes (Ad5-CL), which demonstrated that Ad5-CL was more capable of protecting Ad5 from neutralization. In vivo, Ad-hE/Lipo treatment in the murine CT26 tumor model by intratumoral injection resulted in marked suppression of tumor growth and prolonged survival time, which was associated with a decreased number of microvessels and increased apoptosis of tumor cells. In conclusion, recombinant endostatin adenovirus encapsulated with cationic liposome effectively inhibited CAR-deficient tumor growth through an antiangiogenic mechanism in murine models without marked toxicity, thus showing a feasible strategy for clinical applications.

[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.

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.

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.

Suppression of human MDA-MB-435S tumor by U6 promoter-driven short hairpin RNAs targeting focal adhesion kinase.

PURPOSE: Focal adhesion kinase (FAK) is a non-receptor protein tyrosine kinase implicated in cancer cell survival, proliferation, and in various steps in the metastatic cascade. In the present study, we took advantage of a cationic liposome as gene carrier and targeted FAK function through both in vitro and in vivo approaches. METHODS: We utilized a plasmid-encoded hairpin RNA targeting the human FAK mRNA (pGensil2-shRNA/FAK), as a means to inhibit FAK expression for evaluating its anti-tumor effect in vitro and in vivo. Human MDA-MB-435S breast cancer cells were transfected with pGensil2-shRNA/FAK and examined for apoptosis by propidium iodide staining, DNA ladder, and flow cytometric analysis. For in vivo study, subcutaneous breast carcinomatosis models in nude mice were established to evaluate the therapeutic potential of pGensil2-shRNA/FAK. Assessments of proliferation (Ki-67), apoptosis (TUNEL) and angiogenesis (CD31) were done using immunohistochemical analysis. RESULTS: Transcripts expressed from plasmid both in vitro and in vivo were identified by northern blot analysis. pGensil2-shRNA/FAK effectively down-regulated the expression of FAK as demonstrated in vitro by real time RT-PCR and western blot analysis, whereas by real time RT-PCR and IHC staining of MDA-MB-435S tumors growing subcutaneously. Breast cancer cells lacking FAK expression undergo apoptosis in vitro. Systemic delivery of cationic liposome-complexed plasmids targeting FAK, resulted in the diminishment of subcutaneous tumor growth beyond the effects observed with liposomes carrying a non-specific shRNA. This diminishment in growth was associated with elevated levels of apoptosis (TUNEL staining), decreased cell proliferation (Ki-67 staining) and diminished endothelial cell density (CD31 staining). CONCLUSION: These results indicate that the systemic delivery of plasmid DNA targeting FAK function using cationic liposome as a gene carrier, represents a promising avenue for breast cancer therapy.

[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.

Antitumor effect of mSurvivinThr34→Ala in murine colon carcinoma when administered intravenously.

Colorectal cancer is one of the most common cancers. Survivin is strongly immunogenic in a fraction of colorectal cancer patients. The present study was designed to determine whether full-length mouse Survivin dominant-negative mutant SurvivinT34A has the antitumor activity in a murine colon carcinoma model. The complex of cationic liposome (DOTAP/Chol) to plasmid pORF9-mSurvivin T34A was administered intravenously in a mouse subcutaneous (S. C.) CT 26 tumor model. Apoptotic cells and anti-angiogenesis were evaluated by fluorescent in situ TUNEL assay and by immunohistochemistry with an antibody reactive to CD31, respectively. A 4 h 51Cr release assay was performed to determine Survivin-specific cytotoxicity. The adoptive transfer of CD8+ or CD4+ T-lymphocytes assay was to further explore the roles of immune cell subsets. We demonstrated the complex of cationic liposome (DOTAP/Chol) to plasmid pORF9--mSurvivin T34A when administered intravenously induced an efficient antitumor activity in a S. C. CT26 tumor model in mice. The main mechanism is involved in three aspects: triggering the apoptosis of tumor cells, inhibiting angiogenesis, and inducing Survivin-specific immune response. Our observations may have potential implications for the further exploration of the treatment of human colorectal cancer by intravenous delivery of dominant-negative mutant Survivin T34A.

[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.

Intratumoral expression of mature human neutrophil peptide-1 mediates antitumor immunity in mice.

PURPOSE: Human neutrophil peptides (HNP1-3), small molecular antimicrobial peptides, are expressed within tumors and associated with tumor necrosis and inhibition of angiogenesis. Recent investigations have suggested that HNP1-3 are likely to be involved in the host immune responses to tumors. EXPERIMENTAL DESIGN: We used recombinant pSec-HNP1, which expresses a secretable form of HNP1, to obtain expression of HNP1 in the tumor milieu in immunocompetent mice to explore the possible roles of HNP1 in tumor immunity. The antitumor effects were investigated in established CT26 colon cancer and 4T1 breast cancer models. RESULTS: HNP1-mediated chemotactic and activating effects on immature dendritic cells were detected both in vitro and in vivo. Intratumoral expression of HNP1 resulted in not only significant tumor growth inhibition but also increased CTL infiltration within tumors. Adoptive transfer of splenocytes and a (51)Cr release assay revealed specific cellular immune responses. Furthermore, increased antibodies were also found in sera from pSec-HNP1-treated mice supporting specific humoral immune responses. Increased apoptosis and decreased angiogenesis were also shown in treated tumors. CONCLUSIONS: These findings indicate that HNP1 can exert multiple antitumor effects through different mechanisms; more importantly, HNP1 mediates host immune responses to tumors in situ through the recruitment and subsequent activation of immature dendritic cells and thus shows promising potential in cancer therapy.

[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.

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.

[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.