[Identification of metastasis-associated proteins of ovarian cancer by proteomics]

OBJECTIVE

To investigate the differenal protein expression profiles of ovarian tumor cell lines with distinct metastatic abilities.

METHODS

The ovarian cancer cell line HO8910 and HO8910pm, derived from same parental cells but exhibited different metastatic ability, were investigated by two-dimensional gel electrophoresis (2-DE)-MALDI-TOF-MS proteomic approach.

RESULTS

Thirty-nine proteins were detected by 2-DE to have expression disparity levels over 2 folds between two cell lines. Eighteen of them were identified by MALDI-TOF-MS. The proteins are involved in apoptosis, extra cellular matrix (ECM), cytoskeleton, growth factor, glycolysis, protein metabolism and immune system.

CONCLUSION

The data are valuable for the identification of differentially expressed proteins involved in the biological behavior of human ovarian cancer.

[Construction of prophylactic recombinant HPV58-attenuated Shigella vector live vaccine and evaluation of its protective efficacy and immunogenicity in the guinea pig keratoconjunctivitis model]

AIM

To construct the prophylactic recombinant HPV58-attenuated Shigella vector live vaccine and evaluate its protective efficacy and immunogenicity in the Guinea pig Keratoconjunctivitis model.

METHODS

The HPV58 L1 gene was cloned into PUCMT, and the recombinant plasmid HPV58 L1-pCVD442 was constructed and introduced into attenuated Shigella (Sf301: deltavirG) with helper plasmid PRK2013 by filter mating. After homologous recombination, the positive colonies in Sf301: deltavirG strains contained HPV58L1 gene were selected and verified by PCR. The expressed HPV58L1 protein was harvested and analyzed by SDS-PAGE and Western blot. The bio-activity of the interested protein was identified by mouse erythrocyte hemagglutination assay, and the VLP formation was proved with transmission electron microscope. Guinea pig Keratoconjunctivitis model was used to evaluate protective efficacy and immunogenicity of the vaccine. 20 days after immunization, serum HPV58L1-IgG, IgA level and serum sf301 LPS- IgG, IgA level were measured by ELISA, and HPV58 L1-specific IgA-ASC and IgG-ASC of spleen and lymph nodes (SVCLN, MDLN, MSLN and pp) were measured by ELISPOT assay.

RESULTS

HPV58 L1 protein with MW 60 kDa was confirmed by Western blot. The ability of the interested protein to self-assemble into VLPs was identified by transmission electron microscope, and the result of murine erythrocyte hemagglutination assay indicated that the given proteins expressed by the recombinant bacillus had similar characteristics as the natural HPV58L1 protein.In the Guinea pig Keratoconjunctivitis Model, animal immune results showed that there were no Keratoconjunctivitis occurred in the immune group(HPV58-attenuated Shigella), and after Sf301 attacking, 80% eyes had no Keratoconjunctivitis occurrence. 20 days after immunization, serum HPV58L1-IgG, IgA level were obviously increased; but serum sf301 LPS-IgG position was just slightly increased; ELISPOT results showed that HPV58 L1-specific IgA-ASC and IgG-ASC of spleen and lymph nodes were also obviously increased.

CONCLUSION

Recombinant HPV58L1-attenuated Shigella vector live vaccine could induce strong humoral immune responses in the immunized animals.

[In situ analysis of distribution of immunocompetent cells in tumor's local draining lymph nodes]

AIM

To observe the distribution of immunocompetent cells (ICCs) in tumor's local draining lymph nodes (LDLN) at different stages of disease including non-metastasis, micro-metastasis and late metastasis.

METHODS

71 LDLN from 22 breast cancer, 28 LDLN from 7 gastric carcinoma were analysed by using catalyzed signal amplification (CSA) immunohistochemical staining. Monoclonal antibodies (mAbs) to perforin, granzyme B, CD8, CD56, CD68, S-100, CD134 and CD25 were used to detect the amount and functional change of ICCs.

RESULTS

Paracortical hyperplasia and sinus histocytosis was mainly observed in tumor's LDLN. As it was reported, the density of S100(+) dendritic cells (DCs) was decreased as the draining lymph nodes became tumor-containing from the status of tumor free (P<0.05), and the morphology of DCs turned to be inactivated. As the lymph nodes were invaded by tumors, the densities of CD134(+) lymphocytes and CD25(+) cells were significantly increased (P<0.01). Furthermore, there was a significant trend of decreasing in the number of activated cytotoxic T lymphocytes (granzyme B(+) cells) in LDLN as tumor progressed from non/micro-metastasis, early metastasis to advanced stage metastasis (P<0.01). There was no obvious difference in distribution of ICC between non/micro-metastasis sentinel lymph nodes and non-sentinel lymph nodes.

CONCLUSION

The dynamic change of the ICCs in LDLN implied that immune response of tumor bearing host tends to be inhibited with the progress of tumors.

Predicting the Nuclear Localization Signals of 107 Types of HPV L1 Proteins by Bioinformatic Analysis

In this study, 107 types of human papillomavirus (HPV) L1 protein sequences were obtained from available databases, and the nuclear localization signals (NLSs) of these HPV L1 proteins were analyzed and predicted by bioinformatic analysis. Out of the 107 types, the NLSs of 39 types were predicted by PredictNLS software (35 types of bipartite NLSs and 4 types of monopartite NLSs). The NLSs of the remaining HPV types were predicted according to the characteristics and the homology of the already predicted NLSs as well as the general rule of NLSs. According to the result, the NLSs of 107 types of HPV L1 proteins were classified into 15 categories. The different types of HPV L1 proteins in the same NLS category could share the similar or the same nucleocytoplasmic transport pathway. They might be used as the same target to prevent and treat different types of HPV infection. The results also showed that bioinformatic technology could be used to analyze and predict NLSs of proteins.

Construction of prophylactic human papillomavirus type 16 L1 capsid protein vaccine delivered by live attenuated Shigella flexneri strain sh42

To express human papillomavirus (HPV) L1 capsid protein in the recombinant strain of Shigella and study the potential of a live attenuated Shigella-based HPV prophylactic vaccine in preventing HPV infection, the icsA/virG fragment of Shigella-based prokaryotic expression plasmid pHS3199 was constructed. HPV type 16 L1 (HPV16L1) gene was inserted into plasmid pHS3199 to form the pHS3199-HPV16L1 construct, and pHS3199-HPV16L1 was electroporated into a live attenuated Shigella strain sh42. Western blotting analysis showed that HPV16L1 could be expressed stably in the recombinant strain sh42-HPV16L1. Sereny test results were negative, which showed that the sh42-HPV16L1 lost virulence. However, the attenuated recombinant strain partially maintained the invasive property as indicated by the HeLa cell infection assay. Specific IgG, IgA antibody against HPV16L1 virus-like particles (VLPs) were detected in the sera, intestinal lavage and vaginal lavage from animals immunized by sh42-HPV16L1. The number of antibody-secreting cells in the spleen and draining lymph nodes were increased significantly compared with the control group. Sera from immunized animals inhibited murine hemagglutination induced by HPV16L1 VLPs, which indicated that the candidate vaccine could stimulate an efficient immune response in guinea pig's mucosal sites. This may be an effective strategy for the development of an HPV prophylactic oral vaccine.

[Mechanism of apoptosis induced by indole-3-acetic acids combined with horseradish peroxidase in leukemia cell line K562]

To investigate the possible mechanism of apoptosis induced by indole-3-acetic acid (IAA) combined with horseradish peroxidase in leukemia cell line K562, cell proliferation and apoptosis of K562 cell were examined by MTT assay and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), respectively; the activity of superoxide dismutase (SOD) and the quantitative change of MDA were measured by biochemical method; changes of free radical were determined by 2, 7-dichlorofluorescin diacetate (DCFH-DA) probe with confocal microscopy. The results showed that of MTT assay and TUNEL indicated that IAA/HRP could significantly inhibit cell proliferation (P < 0.05) and induce apoptosis of K562 cell (P < 0.01), at the same time a positive correlation was found between apoptosis rate and IAA concentration (r = 0.971, P < 0.01). The activity of SOD and the quantitative of MDA increased, accompanied with a rise in IAA concentration. Results detected by DCFH-DA probe indicated that the fluorescence intensity of intracellular free radical increased, as compared with control, and a positive correlation was found. It is concluded that IAA/HRP can inhibit proliferation of K562 cells and induce K562 cell apoptosis, its mechanism may be related with the increase of intracellular free radical due to the effects of IAA/HRP.

Expression of human papillomavirus type 16 L1 protein in transgenic tobacco plants

To develop a plant expression system for the production of the human papillomavirus type 16 (HPV16) vaccine, we investigated whether the HPV16 L1 protein can be expressed in tobacco plants and whether it can be used as the cheapest form of edible vaccine. The HPV16 L1 coding sequence was amplified by PCR using specific primers from the plasmid pGEM-T-HPV16 containing the template sequence, and subcloned into the intermediate vector pUCmT and binary vector pBI121 consecutively to obtain the plant expression plasmid pBI-L1. The T-DNA regions of the pBI-L1 binary vector contained the constitutive Cauliflower mosaic virus (CaMV) 35S promoter and the neomycin phosphotransferase npt II gene, which allowed the selection of transformed plants using kanamycin. The tobacco plants were transformed by co-cultivating them, using the leaf disc method, with Agrobacterium tumefaciens LBA4404, which harbored the plant expression plasmid. The regenerated transgenic tobacco plants were selected using kanamycin, and confirmed by PCR. The results of the Southern blot assay also showed that the HPV16 L1 gene was integrated stably into the genome of the transformed tobacco plants. The Western blot analysis showed that the transformed tobacco leaves could express the HPV16 L1 protein. Furthermore, it was demonstrated by ELISA assay that the expressed protein accounted for 0.034%-0.076% of the total soluble leaf protein, was able to form 55 nm virus-like particles compatible with HPV virus-like particle (VLP), and induced mouse erythrocyte hemagglutination in vitro. The present results indicate that the HPV16 L1 protein can be expressed in transgenic tobacco plants and the expressed protein possesses the natural features of the HPV16 L1 protein, implying that the HPV16 L1 transgenic plants can be potentially used as an edible vaccine.

Expression of Human Papillomavirus Type 16 L1 Protein in Transgenic Tobacco Plants

To develop a plant expression system for the production of the human papillomavirus type 16 (HPV16) vaccine, we investigated whether the HPV16 L1 protein can be expressed in tobacco plants and whether it can be used as the cheapest form of edible vaccine. The HPV16 L1 coding sequence was amplified by PCR using specific primers from the plasmid pGEM-T-HPV16 containing the template sequence, and subcloned into the intermediate vector pUCmT and binary vector pBI121 consecutively to obtain the plant expression plasmid pBI-L1. The T-DNA regions of the pBI-L1 binary vector contained the constitutive Cauliflower mosaic virus (CaMV) 35S promoter and the neomycin phosphotransferase npt II gene, which allowed the selection of transformed plants using kanamycin. The tobacco plants were transformed by cocultivating them, using the leaf disc method, with Agrobacterium tumefaciens LBA4404, which harbored the plant expression plasmid. The regenerated transgenic tobacco plants were selected using kanamycin, and confirmed by PCR. The results of the Southern blot assay also showed that the HPV16 L1 gene was integrated stably into the genome of the transformed tobacco plants. The Western blot analysis showed that the transformed tobacco leaves could express the HPV16 L1 protein. Furthermore, it was demonstrated by ELISA assay that the expressed protein accounted for 0.034%–0.076% of the total soluble leaf protein, was able to form 55 nm virus-like particles compatible with HPV virus-like particle (VLP), and induced mouse erythrocyte hemagglutination in vitro. The present results indicate that the HPV16 L1 protein can be expressed in transgenic tobacco plants and the expressed protein possesses the natural features of the HPV16 L1 protein, implying that the HPV16 L1 transgenic plants can be potentially used as an edible vaccine.

[Carboxyl terminus truncated HPV58 virus L1 protein expressed with baculovirus system and its bioactivity]

To prepare carboxyl terminus truncated human papillomavirus type 58L1 protein, and study on its in vitro bioactivity. PCR was used to amplify carboxyl terminus truncated HPV 58L1 gene, the product was inserted into the PUCMT cloning vector, preparing recombinant PFastBacHTb containing carboxyl terminus truncated HPV58L1 gene. Further more, the recombinant plasmid PfastbacHTb was used to transform DH10Bac cells, constructing recombinant Baculovirus, then the recombinant virus was successfully used to infect Sf-9 insect cells. After incubating at 27 degrees C for 72 hours, the infected cells were collected and total cellular proteins were extracted. The target protein with MW 58KD was revealed by SDS-PAGE and confirmed by Western blot. The interested protein was purified by ProBond purification system. The purified interested protein was identified to self-assemble into VLPs by Transmission electron microscope, and induce murine erythrocyte hemagglutination, indicating that the given proteins had the conformation of VLPs, collecting, HPV58L1 proteins with carboxyl terminus truncation could be efficiently expressed in baculovirus Sf-9 cells expression system, it has identical in vitro bioactivity to the wild type HPV58L1, The present study is fundmental for preparing HPV58L1 prophylactic vaccine.

Analysis of the immunological microenvironment at the tumor site in patients with non-small cell lung cancer

BACKGROUND AND AIMS

Inactivation of tumor-infiltrating lymphocytes by immunomodulating cytokines shed by tumor cells into the tumor local microenvironment might be a potential escape strategy of various tumors from immune-immediate killing. Here, we provide an analysis of the cytokine profile at the tumor site in patients with non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

Using in situ hybridization (ISH), we determined the mRNA expression in lymphocytes and tumor cells for IL-2, INF-gamma, IL-12 (p40), IL-18, IL-4, IL-10, TGF-beta1, IL-1, IL-3, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), TNF-alpha, and TGF-alpha in five fresh pleural effusion samples and 18 tumor tissue samples of patients with NSCLC.

RESULTS

In pleural effusion as well as in tumor tissue of NSCLC patients, the mRNA expression of IL-4, IL-10, TGF-alpha, and TGF-beta1 was significantly higher than that of IL-2, IL-12, IL-18 and INF-gamma. In contrast, the analysis of tuberculosis pleural effusion samples revealed lower mRNA levels for all cytokines and did not show any significant difference among them.

CONCLUSION

The predominant mRNA expression of type II and immunosuppressive cytokines in pleural effusion and tumor tissue of NSCLC patients mirrors an immunosuppressive state in the immunological microenvironment. The present study may, therefore, help to elucidate mechanisms of tumor escape and contribute to the development of an effective immunomodulatory treatment of NSCLC.

Expression of Human Single Chain Interleukin 12 Gene in Drosophila Cells

The hscIL-12 gene(no signal sequence), amplified by PCR, was subcloned into an expressing vector pMT/Bip/V5. The recombinant plasmid was transferedinto Drosophila cell line S2. The secreted hscIL-12 fusion protein was identified by Western blot, and the bioactivity of hscIL-12 was investigated by lymphocyte proliferation assay. The results showed hscIL-12 expressed in S2 cells could stimulate lymphocyte proliferation in dose-dependent manner. hscIL-12 has bioactivity identical to natural interleukin 12. These findings suggest that hscIL-12 is promising in theoretical reseach and in clinical use.

[Study of the infiltrating lymphocyte subsets and transferrin receptor in gastric and colorectal carcinomas]

Infiltrating mononuclear cell (MNC) subsets and transferrin receptor (TfR) expression at the localized lesions were studied in 28 cases of gastric carcinoma and 36 cases of colorectal carcinoma by immunohistochemical technique by using a panel of monoclonal antibodies. The results showed that the percentage of T4+ cells in the infiltrating MNCs decreased while that of T8+ cells increased relatively and the T4/T8 ratios declined along with the progression of the tumor. The TfR positive rates in gastric and colorectal carcinomas were 73.08% and 100% respectively. The expressing intensity of TfR in the tumors correlated with the density of local infiltrating MNC subsets. These findings indicated that the local immune response against tumor moves toward a tendency of developing a deeper inhibitory effect during the tumor progression.

[Effect of duokang jiasu on the cytotoxicity of peripheral blood mononuclear cells]

Duokang Jiasu, a biological reaction modifier widely used in cancer clinics, has been proved that its tumor suppression effect is based on the macrophage activity. The results of this study showed that monocytes treated with Duokang jiasu in vitro has much stronger cytotoxicity against allogenic tumor cells. Incubation of mononuclear cells with Duokang jiasu beforehand could promote both NK and ADCC activities.

Lymphocytes infiltrating human ovarian tumors: synergy between tumor necrosis factor alpha and interleukin 2 in the generation of CD8+ effectors from tumor-infiltrating lymphocytes

Tumor-infiltrating lymphocytes (TIL) were isolated by enzymatic digestion and gradient centrifugation from 18 human ovarian carcinomas. These cells were cultured in a complete medium supplemented with recombinant interleukin 2 (IL2) alone or recombinant IL2 plus recombinant tumor necrosis factor alpha (TNF-alpha), and their growth and antitumor cytotoxicity were determined. TIL cultured in the presence of IL2 plus TNF-alpha (1000 units/ml each) for 6 days showed significantly higher cytotoxicity against fresh autologous tumor targets than did TIL cultured with IL2 alone (e.g., mean lytic units/10(7) cells for 8 TIL preparations were 290 versus 74; P less than 0.05). No differences in [3H]thymidine uptake or natural killer cell activity were observed among these TIL cultures. In titration experiments, optimal synergistic concentrations of IL2 and TNF-alpha were determined as 10(2) and 10(3) units/ml, respectively. Using these concentrations for culturing the TIL, effector cells developed which preferentially lysed autologous tumor and displayed a CD8+ phenotype (up to 75% positive). However, the autologous tumor cytotoxicity mediated by these cultured TIL on day 6 was short lived. By day 12, it was replaced by non-major histocompatibility complex-restricted, lymphokine-activated killer cell-like activity mediated by CD3-CD56+ effector cells. Simultaneously, the production of gamma-interferon and interleukin 1 decreased in these cultures. In contrast to TNF-alpha, anti-CD3 antibody synergized with IL2 to increase 2-3-fold TIL proliferation but not their cytotoxic activity against autologous tumor cell targets. These data suggest that TNF-alpha and IL2 synergize early in culture to induce tumor-reactive CD8+ effectors, some of which may be specific for autologous ovarian tumor cells. However, the conditions needed to sustain the specific autologous tumor responses in long-term cultures of human TIL remain to be determined.

Immunopathological study on human cartilage allografts

The fate of human cartilage allografts and the mechanism of its kinetical development were studied histopathologically and immunohistologically. After transplantation, the grafts underwent necrosis, calcification and were partially invaded by osteoplastic tissue of the host and eventually replaced by bone tissue. Thus, the contour of the transplanted cartilage was kept partially by the living cartilage and the newly-formed osseous tissue. The grafts were surrounded initially by granular tissue and then by scar tissue, in which numerous T cells and a few macrophage infiltrates were noted. In T cells, T4+ lymphocytes predominated but T8+ cells accounted for a small number. B cells were not found within the infiltrates. Most of the infiltrating cells expressed 12 antigens, indicating that the majority of T cells were activated. It was concluded that T lymphocytes mediated cellular immunity played an important role. The chondrocytes of the cartilage did not express HLA I and II antigens before transplantation, but one month later, the living chondrocytes became HLA I and II antigens positive, and the antigen expression became stronger with the elapse of time; this might be induced by lymphokins, especially by interferon produced by the infiltrating lymphocytes. Such an expression of MHC antigens on chondrocytes might contribute to the further enhancement of immunorejection.

Studies of lymphocyte subpopulations in the liver tissue and blood of patients with chronic active hepatitis (CAH)

Monoclonal antibodies to antigens on the surfaces of mononuclear cells (MNC) were used to characterize lymphocyte subpopulations infiltrating portal areas and parenchyma of livers in 31 patients with chronic active hepatitis (CAH). The distribution and numbers of infiltrating lymphocytes were determined in serial sections immunostained by the avidin-biotin-peroxidase complex method. T lymphocytes were the major component of inflammatory cells in the portal tracts. In the peripheral blood and portal areas, T helper-inducer (T4+) cells were the more numerous subpopulation. However, the hepatic lobules and areas of "piecemeal" necrosis always contained more T suppressor-cytotoxic (T8+) cells. The latter were demonstrated in contact with HBsAg-containing hepatocytes in tissues of patients with HBsAg-positive CAH. The mean numbers of T lymphocytes infiltrating the portal and periportal areas of livers from patients with HBsAg-negative and HBsAg-positive CAH were not different. Large numbers of B cells forming distinct follicles were seen in tissues from patients with HBsAg-positive CAH. The presence of increased numbers of portal T and B lymphocytes correlated with progressive liver damage as observed in two patients studied at yearly intervals.