Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mouse Sal sarcoma cells are lethal in the autologous A/J (KkDd) host. In order to improve the immune response to the Sal tumor, Sal cells have been transfected with syngeneic MHC-class-II or allogeneic MHC-class-I genes. MHC-class-II transfectants are uniformly rejected by the autologous host and immunization with them protects against subsequent Sal challenge. The improved immunity is probably the result of enhanced generation of tumor-specific Th cells. We hypothesize that class-II tumor cells trigger an improved Th-cell response because they directly present Sal tumor antigens in the context of class-II molecules to Th cells, by-passing professional APC. Studies by others have demonstrated that antigen presentation requires an intracellular signal transmitted by the cytoplasmic domain of the APC class-II molecule. Sal cells expressing class-II antigens with truncated cytoplasmic domains are as malignant as wild-type Sal cells. These experiments therefore support the role of tumor-cell class-II molecules as antigen presentation elements, and demonstrate the requirement for intact class-II molecules for tumor protection. Sal cells have also been transfected with allogeneic MHC-class-I genes. Although Kb-transfected cells are not rejected by A/J mice, Db-transfected Sal cells and Kb- plus Db-transfected cells are rejected. The Db transfectants effectively immunize A/J mice against subsequent Sal challenge. These experiments demonstrate that expression of certain allogeneic MHC-class-I genes can lead to tumor-specific immunity, and that such transfectants can protect against challenges of wild-type tumor cells. Transfection of tumor cells with syngeneic MHC-class-II or allogeneic MHC-class-I genes may therefore be a potential strategy for improving tumor-specific immunity in the autologous host.
Int J Cancer Suppl 1991
PMID:Tumor-specific immunity can be enhanced by transfection of tumor cells with syngeneic MHC-class-II genes or allogeneic MHC-class-I genes. 190 55

Transfection of syngeneic MHC class II genes into the lethal mouse SaI tumor abrogates the malignancy of the tumor in the autologous host, and protects the host against subsequent challenges with the wild type class II- tumor. We have hypothesized that the transfectants induce protective immunity by functioning as APC for tumor peptides, and stimulating tumor-specific Th cells. Recent in vitro studies suggest that Ag presentation by class II-restricted APC requires the cytoplasmic domain of the class II molecule, and may involve intracellular signaling via the cytoplasmic domain. To determine if the class II cytoplasmic domain is required for enhanced tumor-specific immunity, SaI mouse sarcoma cells were transfected with syngeneic Aak and Abk genes with truncated cytoplasmic domains. These transfectants are as malignant as wild type class II- SaI cells in autologous A/J mice. Stimulation of tumor-specific immunity by class II+ tumor cells is therefore dependent on the class II cytoplasmic region, and may involve intracellular signaling events.
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PMID:Abrogation of tumorigenicity by MHC class II antigen expression requires the cytoplasmic domain of the class II molecule. 191 72

The purpose of this work was to compare the efficacy of immunizing mice with a soluble vs a cell-associated form of a tumor Ag. A murine B cell tumor (2C3), which displays an Id on its cell surface, grows progressively and gives rise to Id-negative tumor variants in nonimmunized animals. We previously reported that the tumor variants arise as a consequence of Id-specific T cell suppression of the Id+ tumor. The Id-specific effector T cells are CD4+, CD8-. Based upon these findings vaccination protocols have been designed and tested to determine whether the expansion of tumor-specific effector T cells would eliminate the Id+ tumors and prevent the subsequent generation of Id- tumor variants in vivo. MHC-restricted T cells typically recognize soluble Ag subsequent to modification by an APC, and APC may ultimately express a processed form of the Ag that is different from that expressed on the surface of the tumor cells. Based upon this assumption, the efficacy of immunizing mice with cell-associated 2C3 Id was compared to immunization with a soluble form of the same Id. Mice were immunized with either irradiated 2C3 cells or syngeneic spleen cells to which 2C3 protein was covalently linked. These immunization protocols provided a complete and lasting protection against a tumor challenge of up to 1 x 10(6) tumor cells. In contrast, most mice hyperimmunized with a soluble form of the Id did not survive this level of tumor challenge in spite of the production of significant levels of anti-Id antibodies. Mice immunized with the soluble form of the Id, which did survive, produced slowly progressing tumors expressing a 1000-fold less of the marker Id. These results illustrate the importance of understanding and properly exploiting a host's natural response to a tumor-specific Ag when designing effective immunization protocols for cancer therapy.
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PMID:Vaccination with membrane-associated idiotype provides greater and more prolonged protection of animals from tumor challenge than the soluble form of idiotype. 197 19

The host immune response toward autologous human cancer is subject to regulation by the immunoregulatory network. We show that certain CD4+ T cell clones, derived from melanoma involved lymph node lymphocytes and from PBL stimulated by autologous melanoma cells, selectively down-regulated the induction of cytotoxic immune response of PBL against the respective autologous melanoma cells in two autologous systems. In both systems, only the generation of cytotoxic response against the autologous melanoma cells were suppressed. Cytotoxic response against EBV-infected autologous lymphoblastoid cell line in one case and cytotoxic responses against allogeneic targets in the other were not affected. In addition to suppressor activity selectively expressed against the autologous melanoma cells, the T cell clones up-regulated their Tac receptors when cocultured with the autologous melanoma cells and APC. These results support the existence of a putative tumor Ag-driven activation of regulatory T cells that affect cytotoxic immune response, in vitro, against autologous human melanoma.
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PMID:Autologous melanoma-induced activation of regulatory T cells that suppress cytotoxic response. 197 29

Loss of heterozygosity (LOH) and K-ras mutation were analyzed in 111 colorectal polyps and 26 invasive carcinomas from 40 patients with familial adenomatous polyposis of distinct histopathological types. LOH, being less than 2% in moderate adenomas, was detected on chromosome 5q (20%) in severe adenomas, on 5q (26%) and 17p (38%) in intramucosal carcinomas, and on 5q (52%), 17p (56%), 18 (46%), and 22q (33%) in invasive carcinomas. LOH on chromosome 5q occurred most frequently in the region close to the APC gene both in adenomas and carcinomas, and a loss of the normal allele of the APC gene was demonstrated in 3 cases. K-ras mutation markedly increased in the step of development from moderate (11%) to severe (36%) adenomas. These results suggest the following mechanisms for the development of colon tumors in patients with familial adenomatous polyposis: (a) the heterozygous mutant/wild-type condition at the APC gene causes formation of mild or moderate adenoma; (b) the loss of the normal allele in the APC gene leads to a change from moderate to severe adenoma; (c) LOH on chromosome 17p contributes to the conversion of adenoma to intramucosal carcinoma; (d) LOH on other chromosomes, such as 18 and 22q, are involved in the progression of intramucosal carcinoma to invasive carcinoma; and (e) K-ras mutation may also affect the development of moderate to severe adenoma.
Cancer Res 1990 Nov 15
PMID:Genetic changes and histopathological types in colorectal tumors from patients with familial adenomatous polyposis. 197 14

Activated ras proto-oncogenes contribute to the pathogenesis of many animal and human malignancies. ras proto-oncogenes are generally activated by point mutations within codons 12 or 61, which result in the expression of ras protein (p21) bearing characteristic single amino acid substitutions at the corresponding residues. The purpose of the current study was to determine whether the presence of single transforming amino acid substitutions can render normal ras protein immunogenic and, thus, a possible target for T cell-mediated tumor therapy. In initial experiments, C57BL/6 mice were immunized with a synthetic peptide corresponding to residues 5 through 16 of p21 containing the transforming substitution of arginine for normal glycine at residue 12. The results demonstrated that class II MHC-restricted T cells which were specific for the peptide could be elicited, and that the peptide-induced T cells could specifically recognize the corresponding intact p21 ras protein. Recognition of p21 ras protein by peptide-specific T cells implies that C57BL/6 APC can process the activated ras protein in a fashion that allows presentation of digested protein by class II MHC molecules in a configuration similar to the configuration with synthetic peptide. Evaluation of the immunogenicity of peptides containing alternative transforming amino acid substitutions of ras protein demonstrated that some, but not all, were immunogenic in individual strains of mice. Therefore, although ras protein-specific T cells can be elicited by immunization with synthetic peptides, not all of the potential ras mutations commonly associated with malignancy may be recognizable by T cells from all individuals.
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PMID:T cell recognition of transforming proteins encoded by mutated ras proto-oncogenes. 200 90

A research project initiated in 1978 comprised establishment of a national polyposis registry, a genetic linkage study using classical and DNA markers, an in vitro study of fibroblasts for transformation parameters and chromosome instability, and a comparative study of DNA-RFLPs in cancer and constitutional tissue. The linkage study (to be reported elsewhere) confirmed the recently reported close linkage between the polyposis gene locus APC and D5S71. No in vitro test for the presence of the APC gene has been confirmed or revealed, but we detected increased chromosomal instability on a statistical basis and also recorded abnormal DNA-repair. As per 1. January 1988 the prevalence of adenomatosis of colon and rectum in Norway was 1/43,500. Among patients born in the period 1931-1950 the incidence at birth of developing the disease is 1/20,000 and the mutation rate is 1/72,000 per gamete per generation. In Norway new mutants in healthy families will comprise 1/3-1/2 of all new cases in the coming two decades, or one of 36,000 births.
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PMID:[The polyposis project]. 253 47

The efficacy of two methods of chemotherapy in the treatment of patients with advanced ovarian cancer was compared on the basis of survival curves; one consisted of remission induction therapy alone with a combination of cisplatin (CDDP), adriamycin (ADM) and cyclophosphamide (CPM) (induction PAC therapy), and the other consisted of induction PAC therapy and additional maintenance therapy with cyclic PAC (cyclic PAC therapy). The subjects of the study were patients with advanced ovarian cancer in stages III and IV. Sixty-eight patients received induction PAC therapy alone and seventeen patients received both induction and cyclic PAC therapy. Demographic factors such as age at initial presentation, the stage of cancer (III or IV), surgical procedure, histological classification, number of courses of induction PAC, response rate, site of residual tumor after surgery and induction PAC therapy, and reduction rate of CA125 were compared in the two groups. When analyzed by the chi 2 test, none of these factors was significantly different in the two groups. Patients in the induction PAC therapy group received a median total dosage of CDDP 360 mg, ADM 235mg, and CPM 2.246mg. Patients in the cyclic PAC therapy group received CDDP 592mg, ADM 490mg, and CPM 4.642mg. Thus, the dosage of anticancer agents administered to the latter group was about twice as great as that administered to the former group. According to the Kaplan-Meier method, survival rates for the induction PAC therapy group were 88.2% for one year, 50.0% for two years, 28.0% for three years, and 8.8% for five years. The median survival period was 23 months.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The study of cyclic maintenance chemotherapy with cisplatin, adriamycin, and cyclophosphamide (cyclic PAC chemotherapy) in patients with advanced ovarian cancer]. 259 16

Anticancer chemotherapy with cisplatin (CDD) as the main drug (combined with adriamycin (ADM) and cyclophosphamide (CPM), PAC therapy) was performed on patients with ovarian cancer. Urinastatin (US) was concurrently administered to assess its effectiveness in preventing CDDP-induced nephrotoxicity. Twenty-two patients with gynecological malignant tumor were treated with PAC therapy, and of these, twelve concurrently received US. The ten who did not receive US served as the control. As a rule, one course of PAC therapy consisted of 50mg/m2 CDDP, 50mg/m2 ADM and 500mg/m2 CPM. Before the administration of CDDP, US 100,000 units was administered by I.V. drip infusion and after the administration, US 400,000 units was again administered by I.V. drip infusion at a speed of 100,000 to 200,000 units/hour. A total of approximately 3,500ml of fluids was administered I.V.. Each course of PAC therapy took 7 to 14 hours to complete. The control group underwent PAC therapy in a regimen not including US. As indexes of nephrotoxicity, serum levels of BUN, creatinine (Cr), and creatinine clearance (Ccr), and N-acetyl-beta-glucosaminidase (NAG), gamma-glutamyl transpeptidase (gamma-GTP), and arylamidase (AA) activity in the urine was determined before treatment and at days 1, 2, 3, 7, 14, and 21 after the initiation of PAC therapy. Changes in serum BUN, Cr, and Ccr levels after CDDP administration in the group with and the group without concurrent US were similar. Urinary gamma-GTP, AA, and NAG activity remained unchanged after CDDP administration in the group with concurrent US. In contrast, in the group without US, this urinary enzyme activity was transiently increased after CDDP administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Preventive effect of urinastatin on cisplatin-induced nephrotoxicity]. 259 19

The growth-inhibitory activity of recombinant human tumor necrosis factor (rH-TNF: PAC-4D) against 32 human cultured cell lines derived from leukemias and lymphomas (7 T cell, 11 B cell, 5 non-T,non-B cell and 9 myeloid cell lines) was measured quantitatively by in vitro regrowth assay. The growth of two non-T,non-B-cell lines (Reh, P30/OHK) and six myeloid cell lines (ML-1, U937, THP-1-0, P31/FUJ, P39/TSU, HEL) was found to be significantly inhibited by a 72 hr treatment with PAC-4D. Although the levels of sensitivity of these cell lines to PAC-4D were different, it was common to all these cell lines that increasing the dose of PAC-4D did not augment the growth-inhibitory action above a certain level. Neither dose-dependent nor time-dependent growth-inhibitory action was observed, namely, exposure to 100 U/ml of PAC-4D for 48 hr was sufficient to exhibit maximum growth-inhibitory action. Furthermore U937 cells were found to become completely resistant to PAC-4D during a continuous 12-day exposure to it. This resistance, however, was lost on culture of the cells with PAC-4D-free growth medium for 15 days. These results suggested that some non-T,non-B acute lymphoblastic leukemias and acute myelogenous leukemias might show an initial response to PAC-4D therapy, but prolonged administration might induce resistance to PAC-4D rather than increase the anti-tumor effect.
Jpn J Cancer Res 1987 Nov
PMID:Potential limitation of growth-inhibitory action of recombinant human tumor necrosis factor (PAC-4D) due to easy induction of resistance: evidence in vitro. 282 76


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