Qun Tao

Pivotal Study of Iodine-131-Labeled Chimeric Tumor Necrosis Treatment Radioimmunotherapy in Patients With Advanced Lung Cancer

PURPOSE Tumor necrosis treatment (TNT) uses degenerating tumor cells and necrotic regions of tumors as targets for radioimmunotherapy. Previous studies in animal tumor models and clinical trials have demonstrated that when linked to the therapeutic radionuclide iodine-131, recombinant chimeric TNT antibody ((131)I-chTNT) can deliver therapeutic doses to tumors regardless of the location or type of malignancy. Therapeutic efficacy and toxicity of (131)I-chTNT in advanced lung cancer patients were studied in this pivotal registration trial. PATIENTS AND METHODS Patients with advanced lung cancer were treated with systemic or intratumoral injection of (131)I-chTNT in eight oncology centers in China. The objective response rate (ORR) was assessed as the primary end point. RESULTS All 107 patients who were entered onto the study and completed therapy had experienced treatment failure after prior radiotherapy or chemotherapy a mean of three times. The results showed an ORR of 34.6% (complete response, 3.7%; partial response, 30.8%; no change, 55.1%; and progressive disease, 10.3%) in all patients and 33% in 97 non-small-cell lung cancer patients. A biodistribution study demonstrated excellent localization of the radioactivity in tumors in both systemically and intratumorally injected patients. The most obvious adverse side effect was mild and reversible bone marrow suppression. CONCLUSION Radioimmunotherapy with (131)I-chTNT was well tolerated and can be used systemically or locally to treat refractory tumors of the lung.

Tumor cell membrane-bound heat shock protein 70 elicits antitumor immunity

A novel membrane-bound heat shock protein 70 (mbHSP70) was expressed on the surface of the mouse mastocytoma cell line P815 to enhance immunogenicity of tumor cells. The in vivo effect of mbHSP70 was evaluated by comparing the growth of mbHSP70 cells to that of mock-transfected cells in DBA/2 mice. Fifty percent mice rejected mbHSP70 cells while 100% mice developed tumors in the counterparts. We then tested whether vaccination with these cells would elicit a protective antitumor response by injecting mice with either inactivated mbHSP70 cells or mock-transfected cells and challenging them with wild-type P815 cells. MbHSP70 cells-treated mice grew small tumors that soon disappeared in all animals. In contrast, 60% of animals receiving the mock-transfected cells vaccine grew large tumors and died. Lymphocytes from mbHSP70-vaccinated mice were able to kill wild-type P815 cells, suggesting that the antitumor response involved CTL. However, the activity of NK from mbHSP70 and mock-transfected cells vaccinated mice also increased. It implied that the non-specific immunity was also involved in tumor rejection. These findings indicate that the tumor cell membrane-bound HSP70 can be used as cancer vaccine to elicit protective antitumor immunity.

Interleukin- 18 gene transfer increases antitumor effects of suicide gene therapy through efficient induction of antitumor immunity

To increase the antitumor effects of cytosine deaminase (AdCD) gene therapy and induce more potent antitumor immunity, Th1 cytokine interleukin-18 encoded adenovirus (AdIL18) was combined with adenovirus encoding CD (AdCD) for the therapy of established murine B16 melanoma. Combination therapy of the tumor-bearing mice with AdIL18 and AdCD/5FC inhibited the growth of the subcutaneous B16 tumors more significantly, compared with AdIL18 or AdCD/5FC alone. In vivo depletion analysis with anti-CD4, anti-CD8 or anti-NK 1.1 McAb illustrated that both CD8+ T cells and CD4+ T cells played key roles in the augmented antitumor response of the combined therapy. Peptide/MHC tetramer represents a powerful and general tool for rapid, highly sensitive, and direct analysis of antigen-specific T cells. In this study, we prepared H-2Kb/TRP- 2180–188 tetramer, which was demonstrated to bind H-2Kb-restricted, B16 melanoma-specific CD8+T cells. B16 specific H-2Kb/TRP2180–188 tetramer was used to stain the tumor-specific CD8+ T cells and the results showed that CD8+ tetramer+ T cells were about 3–5% of the splenic CD8+ T cells derived from tumor-bearing mice after combined therapy. The CTL cytotoxicity was markedly induced in mice after combined therapy, suggesting efficient induction of tumor-specific CD8+ T cells after combined gene therapy with AdCD/5FC/AdIL18. IL-18 gene transfer could significantly augment the cytotoxicity of NK cells and macrophages, and increase the production of interleukin-2 and interferon-γ, as compared with treatments with AdCD/5FC, AdlacZ/5FC or PBS. These data suggested that in vivo IL-18 gene transfer could augment the antitumor effects of CD suicide gene therapy through efficient induction of antitumor immunity.

Induction of potent antitumor response by vaccination with tumor lysate-pulsed macrophages engineered to secrete macrophage colony-stimulating factor and interferon-γ

Adoptive transfer of activated macrophages, being both effector cells and antigen-presenting cells, represents a promising approach to immunotherapy of cancer. In order to get activated macrophages with increased antitumor potential, in the present study, murine peritoneal macrophages were transduced with human macrophage colony-stimulating factor (M-CSF) and murine interferon-γ (IFNγ) by recombinant adenovirus infection. The results demonstrate that M-CSF and IFNγ gene-modified macrophages exhibited higher expression of MHC-II, B7.1 and ICAM-1, increased antigen-presenting activity and cytotoxicity. It was also shown that they secreted more tumor necrosis factor, interleukin-1 and nitric oxide. In vivo experiments showed that in previously initiated murine pulmonary metastatic melanoma, tumor lysate-pulsed, M-CSF and IFNγ gene-modified macrophages elicited more potent antitumor effects than tumor lysate pulsed M-CSF or IFNγ gene-modified macrophages. Cytotoxic T lymphocyte (CTL) activity, IFNγ and tumor-necrosis factor production of the splenocytes increased significantly in mice after intravenous injection of the gene-modified macrophages. M-CSF and IFNγ gene-modified macrophages may act as activated effector and antigen-presenting cells, thus eliciting a more potent antitumor response.

Adenovirus-mediated GM-CSF gene and cytosine deaminase gene transfer followed by 5-fluorocytosine administration elicit more potent antitumor response in tumor-bearing mice.

Antitumor effects of combined transfer of suicide and cytokine genes were investigated in this study. Adenovirus harboring E. coli cytosine deaminase gene (AdCD) and adenovirus harboring murine granulocyte–macrophage colony-stimulating factor gene (AdGMCSF) were used simultaneously for in vivo gene transfer in melanoma-bearing mice. Growth inhibition of established tumors and prolongation of survival period were observed more significantly in tumor-bearing mice after transfection with AdGMCSF and AdCD followed by continuous injection of prodrug 5-fluorocytosine (5FC) when compared with mice treated with control adenovirus AdlacZ/5FC, AdCD/5FC or AdGMCSF alone (P < 0.01). after combined therapy the expression of mhc-i (h-2db) and B7–1 molecules on freshly isolated tumor cells increased greatly and more dendritic cells and CD8+ T cells infiltrated into the tumor mass. The activity of specific cytotoxic T lymphocytes was also found to be induced more significantly after the combined therapy. Further experiments showed that apoptosis of tumor cells and induction of antitumor immune response might be involved in the mechanisms of the tumor cell killing by the combined therapy. Our results demonstrated that combined transfer of the GM-CSF and CD suicide genes, being able to inhibit the growth of melanoma synergistically and induce specific antitumor immune response efficiently, thus addressing the drawbacks of suicide gene therapy or cytokine gene therapy which were proved to be not satisfactory when used alone, might be of therapeutic potential for gene therapy of cancer.

Adenovirus-mediated lymphotactin gene transfer improves therapeutic efficacy of cytosine deaminase suicide gene therapy in established murine colon carcinoma.

Lymphotactin (Ltn) is the sole member of C chemokines which attracts T cells and NK cells specially. Ltn gene was transferred in vivo to improve the antitumor efficacy of cytosine deaminase (CD) gene therapy. Upregulation of CD80 and CD54 on murine CT26 colon carcinoma cells was observed after combined transfection with adenovirus encoding CD (AdCD) and adenovirus encoding murine Ltn (AdLtn) followed by administration of 5-fluorocytosine (5FC) in vitro. AdCD/5FC treatment also increased the expression of CD95 and induced obvious apoptosis of CT26 cells. After combined treatment with AdLtn and AdCD/5FC, the pre-established murine model with subcutaneous CT26 colon carcinoma exhibited most significant tumor growth inhibition, and four of eight tumor-bearing mice were tumor free, while tumors in other mice grew more progressively. Examination of lymphocyte infiltration and cytokine gene expression in tumor tissue revealed that tumors from AdLtn/AdCD/5FC-or AdLtn-treated mice were heavily infiltrated with CD4+, CD8+ T cells and NK cells, and IL-2 and IFN-γ mRNA expression were present in parallel with T cell and NK cell infiltration. Splenic NK and CTL activities increased significantly after the combination therapy. In vivo depletion analysis showed that NK cells, CD4+ T cells and CD8+T cells participated in the antitumor effect of the host with CD8+T cells being the main T cell subset responsible for the enhanced antitumor immune response. These findings suggested that increased immunogenicity and induction of apoptosis of the tumor cells, and efficient induction of local and systemic antitumor immunity of the host might contribute to the enhanced antitumor effects of the combined Ltn and CD suicide therapy.

Induction of antitumor immunity and treatment of preestablished tumor by interleukin-6-gene-transfected melanoma cells combined with low-dose interleukin-2

Transfer of cytokine genes into tumor cells has proven a valuable approach for cancer treatment. In order to generate a more effective cancer vaccine, we transfected the human interleukin-6 (IL-6) gene into B16 melanoma cells. A B16 cell clone secreting the highest level of IL-6 was obtained by G418-resistant selection, limiting dilution and IL-6 assay. The IL-6-gene-transfected tumor cells exhibited in vitro growth inhibition, reduced tumorigenicity and decreased metastatic competence. After immunization with the inactivated IL-6-gene-transfected vaccine, the murine cytotoxic T lymphocyte activity, natural killer activity and lymphokine-activated killer activity increased markedly. After treatment with the vaccine, the tumorbearing mice showed significant growth inhibition of subcutaneous tumor, reduction in pulmonary metastases and extension of survival time. The above therapeutic effect was better when low-dose IL-2 was administered simultaneously, although this dosage of IL-2 had no in vivo antitumor effect. These data demonstrated that IL-6-gene-transfected cancer vaccine has a potent antitumor effect via efficient induction of antitumor immunity, and a better therapeutic effect could be achieved when the vaccine is combined with lowdose IL-2 as adjuvant.

The potent antitumor effects of combined p16 gene and GM-CSF gene therapy through efficient induction of antitumor immunity

Purpose: Tumor suppressor gene therapy and cytokine gene therapy have limited antitumor effects when used alone. Thus, in the present study, we investigated the antitumor potentials of the combined transfer of the p16 tumor suppressor gene and the murine granulocyte-macrophage colony-stimulating factor (GM-CSF) gene. Methods: The adenovirus-harboring p16 gene (Adp16) and adenovirus-harboring GM-CSF (AdGMCSF) gene were utilized for the treatment of established tumors in vivo. The mice were inoculated s.c. with Renca renal carcinoma cells and 3 days later received an intratumoral injection of Adp16 in combination with AdGMCSF. Results: The results demonstrated that tumor-bearing mice treated with Adp16 and AdGMCSF showed more potent inhibition of tumor growth and a prolonged survival period than mice treated with Adp16, AdGMCSF, adenovirus-expressing β-galactosidase or PBS (P < 0.01). Treatments of the mice with Adp16 alone or AdGMCSF alone also showed obvious antitumor effects as compared with those mice treated with PBS (P < 0.05). After combined p16 and AdGMCSF gene therapy, the expression of H-2Kd and Fas molecules on freshly isolated tumor cells increased markedly, and more CD4+ T cells and CD8+ T cells infiltrated in the tumor sites. The cytotoxicity of natural killer cells and specific cytotoxic T lymphocytes increased more significantly after the combined therapy. Conclusions: Our results demonstrated that combination p16 gene and GM-CSF gene therapy could inhibit the growth of established tumors in mice more significantly through efficient induction of antitumor immunity.

Pharmacokinetics and Pharmacodynamics of Recombinant Human EPO-Fc Fusion Protein In Vivo

In this study, the in vivo pharmacokinetics and pharmacodynamics of a novel recombinant human erythropoietin (rhEPO) Fc fusion protein, rhEPO-Fc, were studied in both rodents and rhesus monkeys. Animal models of anemia induced by irradiation, cyclophosphamide and partial renal ablation were used to evaluate therapeutic effects of rhEPO-Fc. We have demonstrated that serum half-life of rhEPO-Fc was 29.5 to 38.9 h at doses of 8, 25, 80 µg/kg in rhesus monkeys and 35.5 to 43.5 h at doses of 16, 50, 160 µg/kg in rats. In anemia animal models, rhEPO-Fc dose-dependently (7.5–30.0 µg/kg in mice, 5.4–21.4 µg/kg in rats and 5.0–10.0 µg/kg in rhesus monkeys) increased reticulocyte level, followed by an increase of RBC count, hemoglobin and hematocrit levels. At reduced intervention frequency of weekly treatments, rhEPO-Fc showed similar hematopoietic effects as compared with rhEPO given three times a week. These results indicated that rhEPO-Fc could potentially be used in treatment of anemia and warrants future clinical trials.

Accelerated recovery of irradiation-induced bone marrow depression by fibroblast-mediated interleukin 6 gene therapy in combination with bone marrow transplantation in mice.

BACKGROUND Both fibroblast-mediated cytokine gene therapy and bone marrow transplantation (BMT) have proven to be efficient protocols for the recovery of bone marrow depression. In this report, the effects of fibroblast-mediated interleukin (IL)-6 gene therapy, in combination with BMT, on the recovery of irradiation-induced bone marrow depression were investigated. METHODS NIH3T3 fibroblast cells engineered to secrete IL-6 (NIH3T3-IL-6) or NIH3T3 cells transduced with the neomycin gene (NIH3T3-Neo), in combination with 10(7), 10(6), or 10(5) syngeneic bone marrow cells, were implanted into irradiated mice. RESULTS The platelets and white blood cells in the peripheral blood of the irradiated mice increased greatly 12 days after implantation of NIH3T3-IL-6 cells and BMT, the white blood cell counts were restored to a normal level 32 days after the combined therapy, and the platelet number was obviously higher than that in mice implanted with NIH3T3-Neo and BMT. Twenty and 25 days after the combined therapy, the mice showed accelerated recovery of colony-forming unit (CFU)-granulocyte/macrophages and CFU-megakaryocytes when compared with the mice implanted with NIH3T3-Neo cells and BMT. Ten days after lethal irradiation with gamma rays, the spleens formed more CFU-spleen in mice implanted with NIH3T3-IL-6 cells and BMT than in mice injected with phosphate-buffered saline or NIH3T3-Neo cells. Combined therapy with NIH3T3-IL-6 cell implantation and BMT delayed the survival period of the hematopoietic-depressed mice significantly when compared with therapy with NIH3T3-Neo cell implantation and BMT. CONCLUSIONS These data demonstrated that the combined therapy of fibroblast-mediated IL-6 gene therapy and BMT could significantly promote the recovery of irradiation-induced hematopoietic depression.