Biomedical subjects

D P Carbone

Publications and source records attributed to D P Carbone.

At least 19 recordsLinked to original sources

PubMed1999

Ionizing radiation enhances immunogenicity of cells expressing a tumor-specific T-cell epitope.

BACKGROUND: p53 point mutations represent potential tumor-specific cytolytic T lymphocyte (CTL) epitopes. Whether ionizing radiation (IR) alters the immunological properties of cells expressing mutant p53 in respect of the CTL epitope generated by a defined point mutation has not been evaluated. METHODS: Mutant p53-expressing syngeneic, nontumor forming BALB/c 3T3 fibroblasts, tumor forming ras-transfected BALB/c 3T3 sarcomas, and DBA/2-derived P815 mastocytoma cells, which differ at the level of minor histocompatibility antigens, were used as cellular vaccines. Cells were either injected with or without prior IR into naive BALB/c mice. Cellular cytotoxicity was assessed after secondary restimulation of effector spleen cells in vitro. RESULTS: Injection of P815 mastocytoma cells expressing the mutant p53 induced mutation-specific CTL in BALB/c mice irrespective of prior irradiation. However, syngeneic fibroblasts or fibrosarcomas endogenously expressing mutant p53 were able to induce significant mutation-specific CTL only when irradiated prior to injection into BALB/c mice. IR of fibroblasts did not detectably alter the expression of cell surface molecules involved in immune response induction, nor did it alter the short-term in vitro viability of the fibroblasts. Interestingly, radioactively-labeled fibroblasts injected into mice after irradiation showed altered organ distribution, suggesting that the in vivo fate of these cells may play a crucial role in their immunogenicity. CONCLUSIONS: These findings indicate that IR can alter the immunogenicity of syngeneic normal as well as tumor forming fibroblasts in vivo, and support the view that ionizing radiation enhances immunogenicity of cellular tumor vaccines.

3T3 Cells↗

PubMed1999

Effect of vascular endothelial growth factor and FLT3 ligand on dendritic cell generation in vivo.

The cytokine FLT3 ligand (FL) enhances dendritic cell (DC) generation and has therefore been proposed as a means to boost antitumor immunity. Vascular endothelial growth factor (VEGF) is produced by a large percentage of tumors and is required for development of tumor neovasculature. We previously showed that VEGF decreases DC production and function in vivo. In this study, we tested the hypothesis that VEGF regulates FL effects on DC generation. In seven experiments, four groups of mice were treated with PBS, VEGF alone (100 ng/h), FL alone (10 microgram/day), or with the combination of FL and VEGF. VEGF and PBS were administered continuously for 14 days via s.c. pumps. FL was given s.c. daily for 9 days, beginning on day 4. Tissues were collected and the number, phenotype, and function of lymph node, splenic, and thymic DCs were analyzed on day 14. As expected, treatment with FL resulted in a marked increase in the number of lymph node and spleen DCs and a smaller increase in thymic DC. Pretreatment of mice with VEGF inhibited these FL effects in lymph nodes and thymus by about 50%, whereas spleen DC numbers were undiminished by VEGF. VEGF treatment in vivo also inhibited the ability of FL to increase the number of hemopoietic precursor cells and the level of maturity exhibited by DC derived from these hemopoietic precursor cells in vitro. VEGF inhibited FL-inducible activation of transcription factor NF-kappaB. These data suggest that VEGF interferes with the ability of FL to promote dendritic cell differentiation from bone marrow progenitor cells in mice and therefore may decrease the therapeutic efficacy of FL in settings where increased numbers of DCs might provide clinical benefits.

Animals↗

PubMed1999

A model for CD8+ CTL tumor immunosurveillance and regulation of tumor escape by CD4 T cells through an effect on quality of CTL.

Understanding immune mechanisms influencing cancer regression, recurrence, and metastasis may be critical to developing effective immunotherapy. Using a tumor expressing HIV gp160 as a model viral tumor Ag, we found a growth-regression-recurrence pattern, and used this to investigate mechanisms of immunosurveillance. Regression was dependent on CD8 T cells, and recurrent tumors were resistant to CTL, had substantially reduced expression of epitope mRNA, but retained the gp160 gene, MHC, and processing apparatus. Increasing CTL numbers by advance priming with vaccinia virus expressing gp160 prevented only the initial tumor growth but not the later appearance of escape variants. Unexpectedly, CD4 cell depletion protected mice from tumor recurrence, whereas IL-4 knockout mice, deficient in Th2 cells, did not show this protection, and IFN-gamma knockout mice were more susceptible. Purified CD8 T cells from CD4-depleted mice following tumor regression had more IFN-gamma mRNA and lysed tumor cells without stimulation ex vivo, in contrast to CD4-intact mice. Thus, the quality as well as quantity of CD8+ CTL determines the completeness of immunosurveillance and is controlled by CD4 T cells but not solely Th2 cytokines. This model of immunosurveillance may indicate ways to enhance the efficacy of surveillance and improve immunotherapy.

Animals↗

PubMed1999

Serum anti-p53 antibodies in gastric adenocarcinoma patients are associated with poor prognosis, lymph node metastasis and poorly differentiated nuclear grade.

Mutation of the p53 tumour suppressor gene often leads to the accumulation of mutant p53 protein in tumour cells. Many cancer patients develop antibodies that recognize the overexpressed p53 protein. The presence of these antibodies is, in some tumour types, associated with poor prognosis. Gastric cancer is a highly prevalent disease associated with a high rate of mortality, there is a need for improved clinical and biological markers for disease behaviour. To investigate the clinical relevance of serum anti-p53 antibodies in patients with gastric adenocarcinoma, we have examined the sera of 501 gastric cancer patients for the presence of serum antibodies against the p53 protein. By immunoblotting analysis using a cell lysate containing overexpressed p53 protein as well as affinity-purified recombinant p53 protein as antigens, we have detected anti-p53 antibodies in 11.2% (61 of 501) of gastric cancer patients, but in none of 46 cancer-free individuals. The presence of anti-p53 antibodies was tightly associated with tumours of higher nuclear grade and lymph node metastasis, and a negative association was found between the presence of anti-p53 antibodies and survival. These results suggest that a preoperative test of serum anti-p53 antibodies in gastric cancer patients can be useful to identify subset of patients who may need gastrectomy with lymph node dissection and post-operative adjuvant therapy.

Adenocarcinoma↗

PubMed1999

Dendritic cells transduced with wild-type p53 gene elicit potent anti-tumour immune responses.

In this study we have tested the concept of using wild-type p53 gene for immunotherapy of cancer. Dendritic cells (DC) were transduced with a human wild-type p53 containing recombinant adenovirus (Ad-p53). About a half of DC transduced with this virus expressed p53 protein by FACS analysis 48 h after infection. Mice immunized twice with Ad-p53 DC developed substantial cytotoxic T lymphocyte (CTL) responses against tumour cells expressing wild-type and different mutant human and murine p53 genes. Very low CTL responses were observed against target cells infected with control adenovirus (Ad-c). Immunization with Ad-p53 provided complete tumour protection in 85% of mice challenged with tumour cells expressing human mutant p53 and in 72.7% of mice challenged with tumour cells with murine mutant p53. Treatment with Ad-p53-transduced DC significantly slowed the growth of established tumours. Thus, DC transduced with wild-type p53 may be a promising new tool for the immunotherapy of cancer.

Adenoviruses, Human↗

PubMed1999

Seven-week continuous-infusion paclitaxel concurrent with radiation therapy for locally advanced non-small cell lung and head and neck cancers.

The goal of these National Cancer Institute-sponsored phase I trials is to determine the feasibility, toxicity, and pharmacokinetics of continuous-infusion (24 hr/d, 7 d/wk, 7 weeks total) intravenous paclitaxel combined with standard, curative-intent thoracic radiation therapy (XRT) for previously untreated, locally advanced non-small cell lung cancer and squamous cell cancer of the head and neck (HNSCC). Eligible patients have locally advanced (T4NXM0 or TXN2-3M0) non-small cell lung cancer ineligible for potentially curative surgical resection or locally advanced HNSCC with an expected 5-year survival rate of less than 25%, as well as a good performance status, adequate hematologic, hepatic, and renal function, and no distant metastases. Non-small cell lung cancer patients receive a total tumor dose of 64.8 Gy megavoltage XRT in 7 weeks at 1.8 Gy once daily, 5 d/wk. Patients with HNSCC receive 70 Gy megavoltage XRT in 7 weeks at 2 Gy once daily, 5 d/wk. Paclitaxel is delivered by continuous intravenous infusion starting 48 hours before XRT and continuing for its duration. The dose of paclitaxel is escalated in cohorts of three patients in a standard phase I design. To date, 49 patients have been entered on both studies and 43 are evaluable for toxicity. Paclitaxel dose is currently at the 17 mg/m2/d dose level, with no dose-limiting toxicity thus far. Clinical outcomes suggest significant activity for this combination. This therapy is feasible and has been well-tolerated through current dose levels. Dose escalation is ongoing.

Antineoplastic Agents, Phytogenic↗

PubMed1999

A phase I single-dose trial of gadolinium texaphyrin (Gd-Tex), a tumor selective radiation sensitizer detectable by magnetic resonance imaging.

Gadolinium Texaphyrin (Gd-Tex) is a radiation sensitizer with a novel mechanism of action that sensitizes both oxic and hypoxic cells, localizes selectively in tumors, and is detectable by magnetic resonance imaging (MRI). This Phase I single-dose trial of Gd-Tex administered concurrently with radiation therapy was carried out to determine the maximally tolerated dose (MTD), dose-limiting toxicities, pharmacokinetics, and biolocalization of Gd-Tex as determined by MRI. Adults with incurable cancers of any histology requiring radiation therapy were eligible. A single i.v. dose of Gd-Tex was followed at least 2 h later by radiation therapy. The Gd-Tex dose was escalated in cohorts of 3 to 5 patients. Thirty-eight patients (median age, 58 years; range, 35-77 years) with incurable cancers of the lung (26), cervix (3), or other solid tumors (9) received a total of 41 single administrations of Gd-Tex. The Gd-Tex dose was escalated from 0.6 to 29.6 mg/kg. Irradiated sites included the thorax, brain, pelvis, bone, soft tissue, and sites of nodal metastases. The MTD was 22.3 mg/kg, determined by reversible acute tubular necrosis as the dose-limiting toxicities. Gd-Tex selectively accumulated in primary and metastatic tumors as demonstrated by MRI. No increase in radiation toxicity to normal tissues was seen. The median half-life of Gd-Tex after single-dose administration is 7.4 h. This study demonstrates that Gd-Tex is well tolerated in doses below the MTD, and that there is selective biolocalization in tumors. The maximum recommended dose for single administrations is 16.7 mg/kg.

Adult↗

PubMed1999

Antibodies to vascular endothelial growth factor enhance the efficacy of cancer immunotherapy by improving endogenous dendritic cell function.

Inadequate function of dendritic cells (DCs) in tumor-bearing hosts is one mechanism of tumor escape from immune system control and may compromise the efficacy of cancer immunotherapy. Vascular endothelial growth factor (VEGF), produced by most tumors, not only plays an important role in tumor angiogenesis but also can inhibit the maturation of DCs from hematopoietic progenitors. Here, we investigate a novel combination of antiangiogenic and immunotherapy based on this dual role of VEGF. Two s.c. mouse tumor models were used: D459 cells, expressing mutant human p53; and MethA sarcoma with point mutations in the endogenous murine p53 gene. Therapy with anti-mouse VEGF antibody (10 microg i.p. twice a week over 4 weeks) was initiated when tumors became palpable. Treatment of established tumors with anti-VEGF antibody alone did not affect the rate of tumor growth. However, anti-VEGF antibody significantly improved the number and function of lymph node and spleen DCs in these tumor-bearing animals. To investigate the possible effects of this antibody on the immunotherapy of established tumors, tumor-bearing mice were immunized with DCs pulsed with the corresponding mutation-specific p53 peptides, together with injections of anti-VEGF antibody. Therapy with peptide-pulsed DCs alone resulted in considerable slowing of tumor growth but only during the period of treatment, and tumor growth resumed after the end of the therapy. Combined treatment with peptide-pulsed DCs and anti-VEGF antibody resulted in a prolonged and much more pronounced antitumor effect. This effect was associated with the induction of significant anti-p53 CTL responses only in this group of mice. These data suggest that inhibition of VEGF may be a valuable adjuvant in the immunotherapy of cancer.

Amino Acid Sequence↗

PubMed1999

Molecular modalities in the treatment of lung cancer.

Despite recent advances in the treatment of lung cancer, long-term survival remains rare. As more information pertaining to the biology of lung cancer is understood, it is hoped that improvements in outcome can be realized with the use of molecularly based therapies. The identification of gene mutations in lung cancer has led to the development of inhibitory therapies, including antisense oligonucleotides and direct injection of tumor-suppressor genes, such as wild-type p53. Other therapeutic approaches are targeted at inhibiting angiogenesis by blocking endogenous growth factors with antibodies or administering natural antiangiogenic substances. Recognition of the dendritic cell as one of the primary cells responsible for antitumor immunity has encouraged studies of immunotherapy for patients with lung cancer. In addition, studies have shown that dendritic cell function is defective in tumor-bearing animals. Research continues to explore of the effect of tumor on immune cell function and ways to overcome such defects. Rationally derived therapies based on these biological findings may advance the treatment, as well as early detection and prevention, of lung cancer, thereby improving patient outcomes.

Angiogenesis Inhibitors↗

PubMed1998

Vascular endothelial growth factor inhibits the development of dendritic cells and dramatically affects the differentiation of multiple hematopoietic lineages in vivo.

Defective function of dendritic cells (DC) in cancer has been recently described and may represent one of the mechanisms of tumor evasion from immune system control. We have previously shown in vitro that vascular endothelial growth factor (VEGF), produced by almost all tumors, is one of the tumor-derived factors responsible for the defective function of these cells. In this study, we investigated whether in vivo infusion of recombinant VEGF could reproduce the observed DC dysfunction. Continuous VEGF infusion, at rates as low as 50 ng/h (resulting in serum VEGF concentrations of 120 to 160 pg/mL), resulted in a dramatic inhibition of dendritic cell development, associated with an increase in the production of B cells and immature Gr-1(+) myeloid cells. Infusion of VEGF was associated with inhibition of the activity of the transcription factor NF-kappaB in bone marrow progenitor cells. Experiments in vitro showed that VEGF itself, and not factors released by VEGF-activated endothelial cells, affected polypotent stem cells resulting in the observed abnormal hematopoiesis. These data suggest that VEGF, at pathologically relevant concentrations in vivo, may exert effects on pluripotent stem cells that result in blocked DC development as well as affect many other hematopoietic lineages.

Animals↗

PubMed1998

Defective function of Langerhans cells in tumor-bearing animals is the result of defective maturation from hemopoietic progenitors.

Langerhans cells (LC), the APCs in the skin, serve as a model for investigation of dendritic cell (DC) function in tissues. DC play a crucial role in the generation of antitumor immune responses. In this study, we investigated the effect of the presence of tumor in vivo on the ability of LC to take up Ag, migrate to draining lymph nodes, and stimulate primary T cell responses. In two animal models, these functions were substantially inhibited. This effect was not restricted to LC located in the skin near a tumor but was also seen at sites distant from the tumor. The duration of tumor exposure, and not its ultimate size, were found to be important, suggesting that tumors could be inhibiting the maturation of LC rather than directly inhibiting their function. Model experiments with radiation chimeras supported this hypothesis. To investigate the potential role of vascular endothelial growth factor (VEGF) in these effects we used anti-VEGF-neutralizing Ab to treat animals bearing tumors. Treatment with the Ab at a dose of 10 microg i.p. per mouse, twice a week for 4 wk, significantly improved the number and function of LC as measured by their ability to migrate to lymph nodes and stimulate primary T cell responses, even at doses that do not affect the growth of these established poorly immunogenic tumors. Thus, inhibition of VEGF signaling may improve DC function in tumor-bearing hosts and possibly serve to improve the efficacy of cancer immunotherapy.

Animals↗

PubMed1998

Vascular endothelial growth factor affects dendritic cell maturation through the inhibition of nuclear factor-kappa B activation in hemopoietic progenitor cells.

Vascular endothelial growth factor (VEGF), produced by almost all tumor cells, affects the ability of hemopoietic progenitor cells (HPC) to differentiate into functional dendritic cells (DC) during the early stages of their maturation. In this study we demonstrate specific binding of VEGF to HPC. This binding was efficiently competed by placenta growth factor (PIGF), a ligand reportedly specific for the Flt-1 receptor. The number of binding sites for VEGF decreased during DC maturation in vitro associated with decreased levels of mRNA for Flt-1. VEGF significantly inhibited nuclear factor-kappa B (NF-kappa B)-dependent activation of reporter gene transcription during the first 24 h in culture. The presence of VEGF significantly decreased the specific DNA binding of NF-kappa B as early as 30 min after induction with TNF-alpha. This was followed on days 7 to 10 by decreases in the mRNA for RelB and c-Rel, two subunits of NF-kappa B. Blockade of NF-kappa B activity in HPC at early stages of differentiation with an adenovirus expressing a dominant I kappa B inhibitor of NF-kappa B reproduced the pattern of effects observed with VEGF. Thus, NF-kappa B plays an important role in maturation of HPCs to DC, and VEGF activation of the Flt-1 receptor is able to block the activation of NF-kappa B in this system. Blockade of NF-kappa B activation in HPCs by tumor-derived factors may therefore be a mechanism by which tumor cells can directly down-modulate the ability of the immune system to generate effective antitumor immune responses.

Antigens, CD34↗

PubMed1998

Immunotherapy of head and neck cancer.

Despite advances in surgical chemotherapeutic and radiotherapeutic techniques, the overall cure rates for head and neck cancer have been disappointing. There is experimental and clinical evidence that deficiencies in the immune system play an important role in the initiation and propagation of cancer. Several strategies have been investigated to try to correct these deficiencies and also to improve the immune response. This article reviews proposed mechanisms of immunosuppression, techniques in nonspecific immunotherapy, use of tumor-infiltrating and cytokine-activated lymphocytes, discoveries and potential uses of tumor antigens, and advances in immunogene therapy in head and neck cancer. These mechanisms of immunotherapy may become an important modality in the treatment of head and neck cancer.

Adjuvants, Immunologic↗

PubMed1997

Overexpression of adenovirus-encoded transgenes from the cytomegalovirus immediate early promoter in irradiated tumor cells.

Efficient expression of therapeutic genes in irradiated tumor cells would facilitate the conversion of a malignant tumor nodule into a cancer vaccine in situ. We reported previously that transgene expression from an adenoviral vector could be markedly enhanced by treating transduced tumor cells with butyrate. In this study, we demonstrated that a similar butyrate effect could be achieved in irradiated tumor cells. In addition, irradiating cells at doses of 2-40 Gy prior to transduction could also amplify recombinant adenoviral transgene products in a cell-type-specific manner. This suggests that adenovirus-mediated gene therapy, radiation therapy, and butyrate-mediated cancer therapy may potentially be formulated into one synergistic protocol for cancer treatment.

Adenoviridae↗

PubMed1997

Genetic immunotherapy of established tumors with adenovirus-murine granulocyte-macrophage colony-stimulating factor.

Increased local production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by genetically modified tumor cells can induce specific antitumor cellular immunity. We constructed a recombinant adenovirus expressing murine GM-CSF and tested it for therapeutic efficacy in a syngeneic murine lung cancer model system. In vitro transduction of Lewis lung carcinoma cells with adenovirus-mGM-CSF suppressed tumor formation in syngenic mice (C57BL/6), and transduced and irradiated Lewis lung carcinoma cells induced regression of pre-established wild-type tumors without in vitro selection for transductants. Low, but significant, levels of specific antitumor cytotoxic T lymphocytes (CTL) were observed in mice inoculated with GM-CSF but not with reporter virus-transduced tumor cells. GM-CSF-transduced cells induced the accumulation of dendritic cells at the site of tumor, consistent with a mechanism involving improved tumor antigen presentation. These data suggest that transduction of tumor cells with recombinant GM-CSF adenovirus may be an effective and practical cancer gene therapeutic strategy.

Adenoviridae↗

PubMed1997

p53 as a target for anti-cancer immunotherapy.

The key to specific and non-toxic cancer therapy is likely to be identification and targeting of processes that are absolutely unique to the tumor. One such approach is to target cells expressing mutations in the oncoproteins that led to the development of the cancer, such as p53. In animal model systems, highly mutant p53-specific cytotoxic T cells can be induced, but it remains to be seen whether this can be translated into clinical practice, and what proportion of tumors will respond. In this review, the potential and problems of immunological targeting of mutant p53 in solid tumors are discussed.

Animals↗

PubMed1997

Oncogenic mutations in ras create HLA-A2.1 binding peptides but affect their extracellular antigen processing.

Point mutations in oncogene products such as ras may create neoantigenic determinants recognizable by T lymphocytes as tumor antigens, that could be marshalled to eliminate a tumor by inducing specific cytotoxic T lymphocytes (CTL) with an appropriate vaccine. Peptide-pulsed dendritic cells are a promising new approach to cancer vaccines. For such an approach to work, the determinant must be appropriately processed to the right size fragment and be presented by an appropriate HLA molecule. We have investigated both of these issues for a series of ras codon 12 and 13 point mutations that contain sequences predicted to bind to HLA-A2.1, the most common class I HLA molecule. We find that not only do the different mutations affect binding to HLA-A2.1, but also they affect extracellular antigen processing in two ways: by influencing the trimming of flanking residues from the longer sequence and by influencing the susceptibility of the optimal decamer to further proteolytic degradation. The influence of internal residues on cleavage of flanking residues downstream demonstrates the importance of distant interactions between separated amino acid side chains and/or conformational effects in determining antigen processing. These results may be important in designing an effective vaccine to induce mutant ras-specific tumor immunity.

Antigen Presentation↗

PubMed1997

Intensive radiation therapy concurrent with up to 7-week continuous-infusion paclitaxel for locally advanced solid tumors: phase I studies.

Patients with locally advanced solid tumors of the lung, head and neck, and malignant astrocytomas usually succumb to their disease despite aggressive standard therapy. Laboratory data suggest that the addition of 1.0 to 10 nmol/L paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), a microtubule stabilizing drug, to radiation therapy may result in significant radiation sensitization, perhaps due to accumulation of cells at G2/M. Relatively low concentrations (1.0 to 10 nmol/L) appear to be optimal for direct cytotoxicity and radiosensitization in vitro. Within this dose range, more prolonged exposure seems to result in higher response rates. The phase I trials reported here are designed to test the combination of paclitaxel, administered by continuous intravenous infusion (24 hours a day, 7 days a week), and standard, curative-intent radiation therapy. The ultimate goal of this study is to improve local and systemic control and survival for patients with these three tumor types. To date, 39 evaluable patients are enrolled in this study; there has been no dose-limiting toxicity up to 6.5 mg/m2/d. Observed toxicities include anemia, lymphopenia, mucositis, and cutaneous toxicities.

Antineoplastic Agents, Phytogenic↗