Search

Suppressor of cytokine signaling 1 (SOCS1) plays a critical role in antitumor immunity. Down-regulating SOCS1 in antigen-presenting dendritic cells (DCs) could enhance antigen-specific antitumor immunity. This study was to investigate the antigen-specific antitumor effect and mechanism of DCs with siRNA-mediated inhibition of SOCS1, stimulated by OK-432 and pulsed with hepatocellular carcinoma cell line HepG2 antigens.The expression of SOCS1 in immature DCs was down-regulated by RNA interference (RNAi). DCs were pulsed with lysate of HepG2 cells and stimulated with OK-432. The morphology of DCs was observed under converted phase microscopy. Phenotypic changes in cells after stimulation were characterized by flow cytometry (FCM). The Alamar Blue assay was adopted to evaluate the activation and proliferation of autologous lymphocytes induced by mature DCs. The cytotoxicity of cytotoxic T lymphocytes (CTLs) elicited by modified DCs to HepG2, EC109 and K562 cells was tested by the lactate dehydrogenase (LDH) assay.Cells displaying a typical morphology and phenotypic properties of mature DCs were obtained successfully. The expression of SOCS1 in DCs was down-regulated by SOCS1 RNAi. Mature DCs showed high expressions of CD80, CD83, CD86, and HLA-DR. Pulsing of DCs with lysate of HepG2 had no influence on the phenotypic properties of DCs. Down-regulating SOCS1 expression enhanced the maturation of DCs. The modified DC tumor vaccine stimulated the proliferation of autologous lymphocytes effectively, and the proliferation rate of T cells was (110.7+/-22.2)%. After being activated by modified DCs, TCLs exerted a specific and effective killing effect on HepG2 cells, but not on EC109 and K562 cells.Mature DCs could induce antigen-specific antitumor immunity against hepatocellular carcinoma after silencing of SOCS1 by siRNA, stimulation by OK-432 and pulsing of DCs with HepG2 cell antigens.

Natural killer (NK) cells are the main effector of antibody-dependent cellular cytotoxicity (ADCC). The activation disorder of NK cells in cancer patients may affect the treatment effect of monoclonal antibody. Reversing the dysfunction of signal transduction of CD16zeta chain in NK cells and combining lymphokine-activated killer (LAK) cells with rituximab may give rise to synergistic effect. This study was to find out whether the activation disorder of NK cells exist in B-cell non-Hodgkin's lymphoma (B-NHL) patients, whether interleukin-2 (IL-2) can reverse the activation disorder in vitro, and whether the combination of rituximab and LAK cells can produce synergistic antitumor effect.Peripheral blood mononuclear cells (PBMCs) were isolated from 69 B-NHL patients and 30 healthy donors by density gradient centrifugation method, and cultured with IL-2 (1 000 U/ml) to prepare LAK cells. The positive rate and median fluorescence intensity (MFI) of CD16zeta chain in PBMCs and LAK cells were detected by flow cytometry (FCM). The expression of CD20 on Raji cells was also detected by FCM. The apoptosis of Raji cells after treatment of rituximab was detected by FCM with Annexin V/PI staining. The cytotoxicity was assessed by lactate dehydrogenase (LDH) release experiment.The positive rate and MFI value of CD16zeta chain on CD56+ cells were significantly lower in B-NHL group than in control group [(63.3+/-16.4)% vs. (97.8+/-3.1)%, P0.001; 1.3+/-1.3 vs. 3.6+/-1.7, P0.001]. There was no significant difference in the positive rate and MFI value of CD16zeta on LAK cells between the 2 groups [(99.3+/-4.1)% vs. (99.7+/-3.9)%, P=0.145; 29.2+/-12.5 vs. 31.4+/-13.8, P=0.44]. At the concentration of 40 mug/ml, rituximab completely combined CD20 antigens on cell membrane. The obvious enhancive effect of rituximab on cell apoptosis appeared at 24 h after treatment. The killing rate of Raji cells was significantly higher in rituximab combined LAK group than in LAK group (P0.05). While the combination of LAK cells and Herceptin (40 mug/ml) didn't make a significant increase as compared with Herceptin alone (P0.05). There was no significant difference in killing rate of Jurket cells between rituximab combined LAK group and LAK group (P0.05).The down-regulation of CD16zeta chain expression widely exists in B-NHL patients, while high dose of IL-2 could enhance the expression of CD16zeta chain greatly in vitro. The combination of rituximab and LAK cells shows strong killing effect on Raji cells.

Mucin-1 (MUC1), a tumor-associated antigen, is an optional molecular target for antitumor immunotherapy protocols. This study was to establish a subcutaneous human esophageal cancer transplantation model with MUC1 high expression in nude mice that closely resembles the biological features of human esophageal cancer, and provide a in vivo model for MUC1-targeting immunotherapy of esophageal cancer.Human esophageal carcinoma cell line EC-109 with MUC1 high expression was cultured, and subcutaneously transplanted into BALB/c athymic nude mice (4-5 weeks old). The growth status of transplanted tumor was observed. These subcutaneous tumors were examined histologically. The expression of proliferating cell nuclear antigen (PCNA) was detected by immunohistochemistry. Cell cycle and MUC1 expression of the transplanted tumor cells were analyzed by flow cytometry.Human esophageal carcinoma transplantation models with MUC1 high expression were successfully established in 6 of the 7 nude mice. The histological and biological characteristics of subcutaneous transplanted tumors were similar to those of human esophageal carcinoma. The mean PCNA label index of subcutaneous transplanted tumor cells was (63.5+/-3.6)%. The mean S-phase fraction of cell cycle was (37.6+/-3.7)%. The positive rate of MUC1 in subcutaneous transplanted tumor cells was 97.5%.Human esophageal carcinoma transplantation model with MUC1 high expression in nude mice is similar to human malignant tumors in biological characteristics, and can be used to investigate the biological characteristics of esophageal carcinoma, as well as provides an applicable animal model for research on MUC1-targeting immunotherapy of esophageal cancer.

Recently, micro-invasive treatments showed well application prospective in treating primary hepatocellular carcinoma (HCC), while tumor immunotherapy is a hot topic in tumor treatment. This study was to investigate the efficacy of cytokine-induced killer cells (CIK) combined micro-invasive treatments (transcatheter arterial chemoembolization and radiofrequency ablation) on the recurrence of HCC.A total of 85 HCC patients without active lesions and metastasis, which were displayed by imaging examination after transcatheter arterial chemoembolization and radiofrequency ablation therapy, were divided randomly into 2 groups: 45 in study group, and 40 in control group. The patients in study group were transfused with CIK cells through hepatic artery after micro-invasive treatments, while the patients in control group were not. The levels of T lymphocyte subsets and native killer (NK) cells in peripheral blood of HCC patients before and after CIK cell transfusion were detected by flow cytometry (FCM). Tumor condition was observed by CT scanning every 2-3 months.The percentages of CD3+, CD4+, and CD56+ effect cells and the proportion of CD4+/CD8+ were increased from (68.6+/-11.0)%, (31.0+/-9.0)%, (15.6+/-7.8)%, and 1.1+/-0.5 to (70.7+/-10.1)% (P0.05), (33.5+/-8.0)% (P0.05), (18.4+/-9.4)% (P0.05), and 1.3+/-0.6 (P0.05) after CIK cell transfusion; while the percentages of CD8+ and CD3+ CD56+ cells were decreased from (31.1+/-7.8)% and (6.4+/-3.5)% to (28.6+/-8.3)% (P0.05) and (5.2+/-3.3)% (P0.05). The 1- and 1.5-year recurrence rates were 8.89% and 15.56% in study group, and 30.00% and 40.00% in control group (Chi(2) = 4.87 and 6.41, P0.05).CIK cell transfusion after micro-invasive treatments may improve the immunologic function in HCC patients, and play an important role in reducing the recurrence rate of HCC.

Nowadays, operation is the main treatment for renal cell carcinoma (RCC). But the prognosis of advanced RCC is poor because of its high recurrence rate and resistance to conventional treatments, such as chemotherapy and radiotherapy. Hence, novel and more effective therapeutic options for advanced RCC are needed. This study was to evaluate the clinical efficacy of autologous renal tumor lysate-loaded dendritic cells (DCs) in combination with cytokine-induced killer (CIK) cells on advanced RCC.Peripheral blood mononuclear cells were isolated from 10 patients with advanced RCC, and cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) to produce DCs. The DCs were pulsed with autologous renal tumor cell lysate. T lymphocytes were cultured with interferon-gamma (IFN-gamma), IL-2, CD3-moAb, and IL-1alpha to prepare CIKs. After nephrectomy, the patients received intradermal DC vaccination weekly for at least 8 times, and CIKs administration biweekly for at least 4 times. Clinical and immunologic responses were evaluated by imaging examination, T lymphocytes subset changes, and delayed-type hypersensitivity (DHT) reaction, respectively.During follow-up of 6-20 months (median, 11 months), 1 case of partial remission (PR), 2 cases of stable disease (SD), and 1 case of progressive disease (PD) were identified in the 4 patients with measurable diseases; 1 case of PD was identified in the 6 patients with no measurable diseases, 1 case was lost, and no progressive disease was identified. When treated for 2 months, the levels of CD3+, CD4+, CD4+/CD8+, CD56+ were increased significantly (P0.05) as compared with those before treatment. DTH reaction was positive in 6 patients, including the patient with PR. Except transient fever and chill, no remarkable adverse event happened during or after the treatment.Autologous tumor cell lysate-pulsed DCs in combination with CIKs shows short-term efficacy on advanced RCC through inducing specific antitumor immunity, and the adverse events are tolerable.

It is well known that the patients with B-Non-Hodgkin's Lymphoma (B-NHL) usually have a poor immune response. CD4(+)CD25(+)-Tregs is a new type of suppressor cell. It plays an important role in the tumor immune suppression. But its distribution and the mechanism of immune suppression in B-NHL are still unknown. The present study was designed to evaluate the proportion of Tregs in peripheral blood of the patients with B-NHL with or without chemotherapy to investigate the mechanism of immune suppression in B-NHL and the effect of chemotherapy on immune system and provide evidence for effective intervention in immune function.The peripheral blood was collected from 39 patients with B-NHL before chemotherapy, 32 patients with B-NHL who achieved partial remission (PR) or complete remission (CR) after 4-6 cycles of chemotherapy, and 25 healthy people. The population of CD4(+), CD8(+), CD4(+)CD25(+), and CD4(+)CD25(+)CTLA4(+) T cells was evaluated by flow cytometry.The total number of lymphocyte, the proportion of CD4(+)T cells, and the ratio of CD4/CD8 in the group of B-NHL before chemotherapy was significant less than those of the healthy group (1.3+/-0.39 x 10(9) versus 2.1+/-0.41 x 10(9); 27.5%+/-4.1% versus 32.9%+/-5.8%; 0.9+/-0.21 versus 1.31+/-0.4), but the percentages of CD4(+)CD25(+)-Tregs and CD4(+)CD25(+)CTLA4(+)-T cells were significantly higher than those of the healthy donors (14.7%+/-3.1% versus 8.4%+/-2.5%; 7.4%+/-1.6% versus 5.1%+/-1.4%). In the group of chemotherapy, although the CD4/CD8 ratio (1.19+/-0.3) was almost near to that of the healthy group, the total number of lymphocytes (0.8+/-0.53 x10(9)) was less than those of the other two groups, and the proportions of CD4(+)CD25(+)-Tregs (20.3%+/-4.1%) and CD4(+)CD25(+)CTLA4(+)-T cells (11.5%+/-2.2%) were higher than those of the other two groups.The population of CD4(+)CD25(+)-Tregs in peripheral blood of the patients with B-NHL with or without chemotherapy was significantly higher than those in healthy donors, which may be one of the important reasons of immunosuppression in B-NHL.

Selenium (Se), an antioxidant, is an essential trace element to human body. It can be used as an anti-aging agent and a tumor cell proliferation inhibitor. To further investigate the effect of selenium in cancer prevention, the authors observed the influence of Se-rich rice extract on the transformation of umbilical blood B lymphocytes stimulated by Epstein-Barr virus (EBV) and expression of EBV early antigen(EBV-EA) in Raji cells.(1) Se-rich rice and general rice extract (dilution of 1:4 or 1:8) were added to mixture of EBV, and then umbilical blood mononuclear cells were added. Lymphoblasts transformation test was then performed. The inhibition rate of B lymphocytes transformation was calculated. (2) Raji cells stimulated by butyrate and croton oil were incubated with Se-rich rice extract. The EBV-EA positive expression rate and the inhibition rate were counted using indirect immunological flurescence method.The transformation of umbilical blood B lymphocytes stimulated by EBV was significantly inhibited by Se-rich rice extract at a concentration of 0.11 g/ml (1:8 diluted). The inhibition rate was 83.4% (P0.01), which was significantly higher than that of the control rice (63.1%) (P0.05). Se-rich rice extract showed significant inhibition on EBV-EA in Raji cells. As the extract concentration was at 0.016 microgram/ml, 0.078 g/ml, and 0.388 microgram/ml, the inhibition rates of EA were 2.85%, 12.88%, and 20.75%, respectively.The transformation of umbilical blood B lymphocytes stimulated by EB virus and expression of EBV-EA in Raji cells may be significantly inhibited by Se-rich rice extract, suggesting that Se-rich rice can be used for preventing nasopharyngeal carcinoma.