Dendritic cells (DCs) are antigen-presenting cells with a unique ability to induce primary immune responses. DCs capture and transfer information from the outside world to the cells of the adaptive immune system. DCs are not only critical for the induction of primary immune responses, but may also be important for the induction of immunological tolerance, as well as for the regulation of the type of T cell-mediated immune response. Although our understanding of DC biology is still in its infancy, we are now beginning to use DC-based immunotherapy protocols to elicit immunity against cancer and infectious diseases.

Immunobiology of Dendritic Cells

Purpose To investigate the efficacy and safety of bevacizumab plus carboplatin and paclitaxel in patients with advanced or recurrent non-small-cell lung cancer. Patients and Methods In a phase II trial, 99 patients were randomly assigned to bevacizumab 7.5 (n = 32) or 15 mg/kg (n = 35) plus carboplatin (area under the curve = 6) and paclitaxel (200 mg/m2) every 3 weeks or carboplatin and paclitaxel alone (n = 32). Primary efficacy end points were time to disease progression and best confirmed response rate. On disease progression, patients in the control arm had the option to receive single-agent bevacizumab 15 mg/kg every 3 weeks. Results Compared with the control arm, treatment with carboplatin and paclitaxel plus bevacizumab (15 mg/kg) resulted in a higher response rate (31.5% v 18.8%), longer median time to progression (7.4 v 4.2 months) and a modest increase in survival (17.7 v 14.9 months). Of the 19 control patients that crossed over to single-agent bevacizumab, five experienced stable disease, and...

Randomized Phase II Trial Comparing Bevacizumab Plus Carboplatin and Paclitaxel With Carboplatin and Paclitaxel Alone in Previously Untreated Locally Advanced or Metastatic Non-Small-Cell Lung Cancer

Reports of spontaneous regressions of metastases and the demonstration of tumor-reactive cytotoxic T lymphocytes indicate the importance of the host's immune system in controlling the devastating course of metastatic renal cell carcinoma1,2,3. Recent research indicates that immunization with hybrids of tumor and antigen presenting cells results in protective immunity and rejection of established tumors in various rodent models4,5,6,7,8. Here, we present a hybrid cell vaccination study of 17 patients. Using electrofusion techniques5, we generated hybrids of autologous tumor and allogeneic dendritic cells that presented antigens expressed by the tumor in concert with the co-stimulating capabilities of dendritic cells. After vaccination, and with a mean follow-up time of 13 months, four patients completely rejected all metastatic tumor lesions, one presented a ‘mixed response’, and two had a tumor mass reduction of greater 50%. We also demonstrate induction of HLA-A2-restricted cytotoxic T cells reactive with the Muc1 tumor-associated antigen and recruitment of CD8+ lymphocytes into tumor challenge sites. Our data indicate that hybrid cell vaccination is a safe and effective therapy for renal cell carcinoma and may provide a broadly applicable strategy for other malignancies with unknown antigens.

Regression of human metastatic renal cell carcinoma after vaccination with tumor cell-dendritic cell hybrids.

Cell surface mucins are large transmembrane glycoproteins involved in diverse functions ranging from shielding the airway epithelium against pathogenic infection to regulating cellular signaling and transcription. Although hampered by the relatively recent characterization of cell surface mucins and the difficulties inherent in working with molecules of their size, numerous studies have placed the tethered mucins in the thick of normal and diseased lung physiology. This review focuses on the three best-characterized cell surface mucins expressed in the respiratory tract: MUC1, MUC4, and MUC16.

Structure and Function of the Cell Surface (Tethered) Mucins

MUC1 is a large, heavily glycosylated mucin expressed on the apical surfaces of most simple, secretory epithelia including the mammary gland, gastrointestinal, respiratory, urinary and reproductive tracts. Although MUC1 was thought to be an epithelial-specific protein, it is now known to be expressed on a variety of hematopoietic cells as well. Mucins function in protection and lubrication of epithelial surfaces. Transmembrane mucins, which contain cytoplasmic tail domains, appear to have additional functions through their abilities to interact with many proteins involved in signal transduction and cell adhesion. The goal of this review is to highlight recent discoveries that suggest that MUC1 may be a multifunctional protein, located on the surfaces of cells as a sensor of the environment, poised to signal to the interior when things go awry.

MUC1, the renaissance molecule.

Immunological unresponsiveness established by the elimination or anergy of self-reactive lymphocyte clones is of importance to immunization against tumor-associated antigens. In this study, we have investigated induction of immunity against the human MUC1 carcinoma-associated antigen in MUC1 transgenic mice unresponsive to MUC1 antigen. Immunization of adult MUC1 transgenic mice with irradiated MUC1-positive tumor cells was unsuccessful in reversing unresponsiveness to MUC1. By contrast, fusions of dendritic cells with MUC1-positive tumor cells induced cellular and humoral immunity against MUC1. Immunization with the dendritic cell fusions that express MUC1 resulted in the rejection of established metastases and no apparent autoimmunity against normal tissues. These findings demonstrate that unresponsiveness to the MUC1 tumor-associated antigen is reversible by immunization with heterokaryons of dendritic cells and MUC1-positive carcinoma cells.

https://www.pnas.org/content/pnas/95/11/6279.full.pdf

Reversal of tolerance to human MUC1 antigen in MUC1 transgenic mice immunized with fusions of dendritic and carcinoma cells

Introduction: With the introduction of new drugs, the efficacy of chemotherapy in non-small-cell lung cancer has been improving. The combination of paclitaxel and carboplatin has shown activity in this disease but is far from curative. Methods: The antiangiogenic agent regimen of TNP-470/minocycline was added to treatment with paclitaxel and carboplatin alone and in combination in animals bearing the Lewis lung carcinoma. Results: Administration of the antiangiogenic regimen prior to, during and after the cytotoxic therapy increased the tumor growth delay 1.6-fold and decreased the number of lung metastases to 20% of the number observed in the control animals. [14C]Paclitaxel, platinum from carboplatin and [14C]albumin levels were determined over a 24-h time course in tumors and normal tissues of animals bearing the Lewis lung carcinoma and pretreated with TNP-470/minocycline or not pretreated. There were higher levels of [14C]paclitaxel, platinum from carboplatin and [14C]albumin in the tumors and some normal tissues of the animals that had received TNP-470/minocycline compared with those that had not received TNP-470/minocycline, especially at the earlier time points. Administration of TNP-470/minocycline to animals bearing the EMT-6 mammary carcinoma increased the cytotoxicity of high-dose paclitaxel toward EMT-6 tumor cells and toward bone marrow CFU-GM. Administration of TNP-470/minocycline to animals bearing the EMT-6 mammary carcinoma also increased the cytotoxicity of carboplatin toward the EMT-6 tumor cells but did not affect the toxicity of carboplatin toward the bone marrow CFU-GM. Conclusions: The addition of TNP-470/minocycline to treatment with paclitaxel and carboplatin resulted in increased antitumor activity and efficacy and further investigation of this combination is warranted.

Paclitaxel/carboplatin administration along with antiangiogenic therapy in non-small-cell lung and breast carcinoma models

Purpose: Jasplakinolide is a novel natural product anticancer agent which acts by inducing over-polymerization of actin. The aim of the current study was to explore the activity of jasplakinolide with hyperthermia and radiation. Methods: The response of human PC-3 and DU-145 prostate carcinoma cells and DU-145 xenografts and the response of the Lewis lung carcinoma to jasplakinolide were studied. Results: Jasplakinolide was cytotoxic toward human prostate carcinoma cells, DU-145, PC-3 and LNCaP in culture, killing 1 log of cells with 0.8, 0.3 and 0.07 \(\)m of drug in 24 h, respectively. The combination of jasplakinolide and hyperthermia resulted in primarily additive cell killing by the two modalities in the three prostate carcinoma lines. In combination with radiation, jasplakinolide produced some diminution in the shoulder of the survival curve of normally oxygenated PC-3 cells and was a radiation sensitizer of hypoxic DU-145 cells and hypoxic PC-3 cells. In vivo, jasplakinolide was an active antitumor agent against the Lewis lung carcinoma and the DU-145 prostate carcinoma xenograft. Jasplakinolide was a radiation sensitizer in the Lewis lung carcinoma. Jasplakinolide was also effective against the systemic Lewis lung carcinoma, decreasing lung metastases. Lung metastases were further decreased when jasplakinolide was administered along with radiation to the subcutaneous primary tumor. In the DU-145 tumor, the effects of jasplakinolide and fractionated radiation for 1 or 2 weeks appeared to be primarily additive. Conclusion: Jasplakinolide is an interesting new anticancer agent for which further study both as an anticancer agent and in combined modality regimens is warranted.

Jasplakinolide: interaction with radiation and hyperthermia in human prostate carcinoma and Lewis lung carcinoma.

Introduction: A series of molecules designed to be allosteric effectors of hemoglobin were examined for their potential as radiation sensitizers in vitro and in vivo and for their potential as chemosensitizers in vivo as well as for their antimetastatic effect. Results: At a concentration of 100 μM for 1 h prior to, during and for 1.5 h after radiation exposure, the allosteric effectors decreased the shoulder of the radiation survival curve of normally oxygenated EMT-6 cells and increased the slope of the radiation survival curves of hypoxic EMT-6 cells resulting in dose-modifying factors of 1.8 to 2.1. In vivo the allosteric effectors had antitumor activity against the Lewis lung carcinoma and produced primarily additive tumor growth delay when administered along with fractionated radiation therapy. When administered on days 4 through 18 after tumor implantation, the allosteric effectors, especially JP-7, RSR-13 and RSR-4, were highly effective antimetastatic agents in animals bearing Lewis lung carcinoma. In cell culture, simultaneous exposure to the allosteric effectors (at 100 μM ) effectively sensitized EMT-6 cells to the effects of 4-hydroperoxycyclophosphamide, thiotepa and carboplatin. The allosteric effectors were not very cytotoxic toward EMT-6 tumor cells from tumors treated in vivo with single doses of each molecule nor were these agents very cytotoxic toward bone marrow CFU-GM taken from the same animals. Conclusions: It is likely that the allosteric effectors have a molecular target in addition to hemoglobin. Other possible targets include hydroxymethyl-glutaryl-CoA reductase or microsomal cytochrome b5.

Hideya Takeuchi

Papers

Reversal of tolerance to human MUC1 antigen in MUC1 transgenic mice immunized with fusions of dendritic and carcinoma cells

Paclitaxel/carboplatin administration along with antiangiogenic therapy in non-small-cell lung and breast carcinoma models

Jasplakinolide: interaction with radiation and hyperthermia in human prostate carcinoma and Lewis lung carcinoma.

Allosteric effectors of hemoglobin as modulators of chemotherapy and radiation therapy in vitro and in vivo