RESUMO
For decades, the treatment of advanced prostate cancer was mainly based on the manipulation of the androgen receptor-controlled proliferation pathway. Chemotherapy only played an additional important role with the advent of taxanes. The progress in translational research in recent years has led to innovations in the therapeutic environment. With the decoding of the homologous repair deficiency (HRD) machinery and its ability to be influenced by PARP inhibitors, targeted therapies moved into the therapeutic focus for selected patients. The first positive phase III study for PARP inhibitors is already available. In addition, immunotherapy for the treatment of prostate cancer, which is now widely used in oncology, is also making progress; both checkpoint inhibitors and bispecific antibodies have shown clinically useful activities. Cellular therapies such as CAR T cells, which are directed against prostate-specific membrane antigen (PSMA), are still at an early stage of development. In this review, the authors provide a summary of the basic principles and clinical development of these new therapies.
Assuntos
Imunoterapia , Terapia de Alvo Molecular , Neoplasias da Próstata/terapia , Humanos , Masculino , Neoplasias da Próstata/patologiaRESUMO
The fms-related tyrosine kinase 3 (FLT3) receptor has been extensively studied over the past two decades with regard to oncogenic alterations that do not only serve as prognostic markers but also as therapeutic targets in acute myeloid leukemia (AML). Internal tandem duplications (ITDs) became of special interest in this setting as they are associated with unfavorable prognosis. Because of sequence-dependent protein conformational changes FLT3-ITD tends to autophosphorylate and displays a constitutive intracellular localization. Here, we analyzed the effect of tyrosine kinase inhibitors (TKIs) on the localization of the FLT3 receptor and its mutants. TKI treatment increased the surface expression through upregulation of FLT3 and glycosylation of FLT3-ITD and FLT3-D835Y mutants. In T cell-mediated cytotoxicity (TCMC) assays, using a bispecific FLT3 × CD3 antibody construct, the combination with TKI treatment increased TCMC in the FLT3-ITD-positive AML cell lines MOLM-13 and MV4-11, patient-derived xenograft cells and primary patient samples. Our findings provide the basis for rational combination of TKI and FLT3-directed immunotherapy with potential benefit for FLT3-ITD-positive AML patients.
Assuntos
Leucemia Mieloide Aguda/terapia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/metabolismo , Sequências de Repetição em Tandem/efeitos dos fármacos , Tirosina Quinase 3 Semelhante a fms/metabolismo , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Humanos , Imunoterapia/métodos , Leucemia Mieloide Aguda/metabolismo , Mutação/efeitos dos fármacos , Mutação/genética , Prognóstico , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genéticaRESUMO
Members of the heat shock protein (hsp70) family are either constitutively expressed (hsc70) or can be induced by hyperthermic stress (hsp70). Recombinant hsp70 (rhsp70) stimulates cytokine production from monocytes and enhances NK cell proliferation and cytotoxicity. Here we demonstrate that rhsp70 binds to immature dendritic cells (DC) derived from monocyte precursors and induces their maturation as evidenced by an increase in CD40, CD86 and CD83 expression. Immature DC stimulated to mature with rhsp70 show an enhanced ability to present tyrosinase peptide to specific CTL. Mature DC did not bind rhsp70, suggesting a down-regulation in the expression of its receptor. When rhsp70 was added to monocyte precursors at the same time as GM-CSF and IL-4 it reduced the differentiation of monocytes into DC as shown by a decrease in the level of CD40, CD83, CD86 and HLA-DR expression and an increase in CD14 expression. The constitutively expressed hsc70 had neither a stimulatory effect on the maturation of immature DC nor did it reduce the differentiation of monocytes into DC. These findings demonstrate the specific ability of rhsp70 to induce the maturation of immature DC. Therefore rhsp70 may be useful for its adjuvant like properties in DC based immunotherapy of certain tumors.
Assuntos
Diferenciação Celular/efeitos dos fármacos , Células Dendríticas/citologia , Células Dendríticas/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/farmacologia , Monócitos/citologia , Monócitos/efeitos dos fármacos , Antígenos CD/metabolismo , Células Cultivadas , Técnicas de Cocultura , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Citometria de Fluxo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Imunofenotipagem , Interferon gama/metabolismo , Interleucina-4/farmacologia , Monócitos/metabolismo , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/metabolismo , Fatores de TempoRESUMO
Even though renal cell carcinomas (RCC) are thought to be immunogenic, many tumors express variations in surface molecules and intracellular proteins that hinder induction of optimal antitumor responses. Interferon gamma (IFNgamma) stimulation can correct some of these deficiencies. Therefore, we introduced the complementary DNA (cDNA) encoding human IFNgamma into a well-characterized RCC line that has been selected for development of an allogeneic tumor cell vaccine for treatment of patients with metastatic disease. Studies were performed to determine how endogenous IFNgamma expression influences tumor cell immunogenicity. IFNgamma transductants showed minimal increases in surface expression of MHC class I and adhesion molecules but expression of class II molecules was induced. Proteins of the transporter associated with antigen processing (TAP) and low molecular weight polypeptide (LMP) were constitutively expressed at high levels. The transductants stimulated allospecific cytotoxic T lymphocytes (CTL); however, they were not better than unmodified tumor cells in this capacity. Endogenous IFNgamma expression enhanced tumor cell recognition by MHC-restricted, tumor antigen-specific CTL but suppressed recognition by non-MHC-restricted cytotoxic cells. Thus, the functional consequences of IFNgamma expression varied with respect to the type of effector cell and were not always beneficial for tumor cell recognition.
Assuntos
Vacinas Anticâncer/administração & dosagem , Carcinoma de Células Renais/terapia , Cisteína Endopeptidases , Interferon gama/genética , Neoplasias Renais/terapia , Complexos Multienzimáticos , Linfócitos T Citotóxicos/imunologia , Transfecção/métodos , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Membro 3 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Carcinoma de Células Renais/imunologia , Moléculas de Adesão Celular/metabolismo , DNA Complementar , Técnica Indireta de Fluorescência para Anticorpo , Expressão Gênica , Antígenos de Histocompatibilidade Classe I/metabolismo , Antígenos de Histocompatibilidade Classe II/metabolismo , Humanos , Neoplasias Renais/imunologia , Medições Luminescentes , Complexo de Endopeptidases do Proteassoma , Proteínas/genética , Células Tumorais CultivadasRESUMO
Natural killer cells (NK cells) represent an important component of innate immunity with the capacity to kill many tumor and virus-infected cells. The discovery of several classes of killer cell inhibitory receptors expressed by NK cells that bind specific MHC class I ligands on target cells provides detailed insight into the regulation of NK cells. Inhibitory receptors deliver negative signals following MHC ligand binding that abrogate cytotoxicity and, thus, determine the specificity of NK effector cell function. Here, we describe a novel subset of human memory CD4(+) T lymphocytes that display an NK-like pattern of regulation. These CD4(+) T cells display non-MHC-restricted cytotoxicity that is governed by HLA-Cw7 mediated inhibition. In NK cells, such specificity is associated with expression of the inhibitory receptor p58.2. In contrast, neither p58.2 nor other known inhibitory receptors were detected on these non-MHC-restricted CD4(+) T cells. This suggests that these cells are regulated by a hitherto unknown inhibitory receptor. The finding that interactions with MHC molecules downregulate the function of these CD4(+) T cells suggests that these non-MHC-restricted T cells may function to detect and eliminate cells with aberrant MHC expression.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Antígenos HLA-C/fisiologia , Complexo Principal de Histocompatibilidade/imunologia , Receptores Imunológicos/imunologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Anticorpos Bloqueadores/farmacologia , Anticorpos Monoclonais/farmacologia , Complexo CD3/biossíntese , Antígenos CD4/biossíntese , Linhagem Celular , Células Clonais , Citotoxicidade Imunológica/imunologia , Epitopos de Linfócito T/imunologia , Humanos , Memória Imunológica , Imunofenotipagem , Imunossupressores/farmacologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Ativação Linfocitária , Receptores Imunológicos/análise , Receptores Imunológicos/antagonistas & inibidores , Receptores KIR , Receptores KIR2DL3RESUMO
Renal cell carcinomas belong to the small group of tumors that are able to induce antitumor responses. Here we describe two general types of cytotoxic effector lymphocytes that can eliminate autologous tumor cells and discuss the role that major histocompatibility complex encoded molecules play in governing their specificities. Improved understanding of the cellular and molecular basis of renal cell carcinoma recognition opens new avenues of research with the potential to develop better immunotherapies for patients with metastatic disease.
Assuntos
Reações Antígeno-Anticorpo , Carcinoma de Células Renais/terapia , Imunoterapia , Neoplasias Renais/terapia , Complexo Principal de Histocompatibilidade/imunologia , Linfócitos T Reguladores/imunologia , Humanos , Células Matadoras Ativadas por Linfocina/imunologiaRESUMO
Synthetic peptides corresponding to sequences of HLA class I molecules have inhibitory effects on T cell function. The peptides investigated in this study have sequences corresponding to the relatively conserved region of the alpha 1 helix of HLA class I molecules that overlaps the "public epitope" Bw4/Bw6. These HLA-derived peptides exhibit inhibitory effects on T lymphocytes and have beneficial effects on the survival of allogenic organ transplants in mice and rats. Peptides corresponding to the Bw4a epitope appear most potent as they inhibit the differentiation of T cell precursors into mature cytotoxic T lymphocytes (CTL) and target cell lysis by established CTL lines and clones. To elucidate the mechanism through which these peptides mediate their inhibitory effect on T lymphocytes, peptide binding proteins were isolated from T cell lysates. We show that the inhibitory Bw4a peptide binds two members of the heat-shock protein (HSP) 70 family, constitutively expressed HSC70 and heat-inducible HSP70. Peptide binding to HSC/HSP70 is sequence specific and follows the rules defined by the HSC70 binding motif. Most intriguing, however, is the strict correlation of peptide binding to HSC/HSP70 and the functional effects such that only inhibitory peptides bind to HSC70 and HSP70 whereas noninhibitory peptides do not bind. This correlation suggests that small molecular weight HLA-derived peptides may modulate T cell responses by directly interacting with HSPs. In contrast to numerous reports of HSP70 expression at the surface of antigen-presenting cells and some tumor cells, we find no evidence that HSC/HSP70 are expressed at the surface of the affected T cells. Therefore, we believe that the peptides' immunodulatory effects are not mediated through a signaling event initiated by interaction of peptide with surface HSP, but favor a model similar to the action of other immunomodulatory compounds, FK506 and cyclosporin A, with a role for HSC/HSP70 similar to that for immunophilins, FKBPs and CyP40.
Assuntos
Proteínas de Choque Térmico HSP70/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Linfócitos/imunologia , Oligopeptídeos/metabolismo , Fragmentos de Peptídeos/metabolismo , Sequência de Aminoácidos , Relação Dose-Resposta a Droga , Antígeno HLA-B27/metabolismo , Resposta ao Choque Térmico , Antígenos de Histocompatibilidade Classe I/farmacologia , Humanos , Linfócitos/efeitos dos fármacos , Modelos Imunológicos , Dados de Sequência Molecular , Oligopeptídeos/farmacologia , Fragmentos de Peptídeos/farmacologia , Ligação Proteica , Relação Estrutura-AtividadeRESUMO
A rabbit antiserum "ABR2" was raised against a peptide with sequence identity to 10 amino acids of the cytoplasmic tail of HLA class I heavy chains. Western blotting and immunoprecipitation analyses demonstrate that ABR2 reacts with HLA class I heavy chains. The antiserum reacts poorly with beta 2-microglobulin (beta 2-m)-associated heavy chains and reacts strongly with free heavy chains. ABR2 reacts with immature heavy chains from the endoplasmic reticulum that have yet to bind beta 2-m and mature heavy chains that have dissociated from beta 2-m at the plasma membrane. Comparison with HC10, a mAb that recognizes an epitope defined by polymorphism at residue 62 of the alpha 1 helix of free HLA class I heavy chains, shows that ABR2 reacts with overlapping populations of free heavy chains (for those allotypes that react with both Abs), but it also identifies populations that bind to one Ab and not the other. ABR2 induces dissociation of beta 2-m from HLA-B38 molecules expressed by the human B cell line "TEM," a phenomenon not detected with other allotypes or with the same allotype in a different cell line. This study shows that association of beta 2-m with the extracellular domains of HLA class I heavy chains can cause a change in the cytoplasmic tail that prevents binding of Abs present in the ABR2 antiserum. Similar findings have been made for mouse H-2 class I molecules, which suggests that this is a general property of class I MHC molecules.
Assuntos
Epitopos/análise , Antígenos HLA-A/metabolismo , Antígenos HLA-B/metabolismo , Microglobulina beta-2/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Bovinos , Ensaio de Imunoadsorção Enzimática , Mapeamento de Epitopos/métodos , Antígenos HLA-A/química , Antígenos HLA-A/imunologia , Antígenos HLA-B/química , Antígenos HLA-B/imunologia , Antígenos HLA-C/química , Antígenos HLA-C/imunologia , Antígenos HLA-C/metabolismo , Humanos , Dados de Sequência Molecular , Testes de Precipitina , Células Tumorais Cultivadas , Microglobulina beta-2/metabolismoRESUMO
Strong peptide dependency of HLA-B*3501-specific alloreactive T-cell clones was observed in the recognition of cells bearing closely related B35 variants. The single amino acid exchange in the beta-pleated sheet of B*3503 completely abolished the responses of all clones, whereas an amino acid exchange in the alpha 2 helix of the newest B35 member (B*3508) only altered allorecognition of one T-cell clone, demonstrating the differential impact of these positions on peptide binding to B35 molecules. In contrast to T cells, a mAb (TU165) recognizing the B35 specificity in a peptide-dependent manner bound to the B35 variants irrespective of their sequence heterogeneity. However, quantitative binding differences were detected with cells bearing the same B35 alleles. This is most likely due to variations in the amount of peptide(s) that associates with B35 and forms the ligand seen by this mAb. These results reveal how naturally occurring single amino acid substitutions have led to generation of functionally distinct molecules of another multimember HLA class I cluster.
Assuntos
Antígeno HLA-B35/imunologia , Linfócitos T Citotóxicos/imunologia , Sequência de Aminoácidos , Anticorpos Monoclonais , Sequência de Bases , Ligação Competitiva , Linhagem Celular , Genótipo , Humanos , Dados de Sequência Molecular , Peptídeos/imunologiaRESUMO
A mouse monoclonal antibody of IgM class (TU165) was produced using Epstein-Barr virus (EBV)-infected mutant cells derived from the human BJAB-B95.8.6 cell line as immunogen. Binding studies with several HLA deletion mutant cell lines indicated that TU165 recognized the HLA-B35 molecule. In a panel of 89 EBV-transformed lymphoblastoid cell lines, all HLA-B35+ cells (n = 24) reacted with TU165 while all but two HLA-B35- lines (n = 65) were unreactive (r = 0.95). Surprisingly, peripheral blood lymphocytes of HLA-B35+ donors were unreactive; however, strong enhancement of TU165 recognition was observed with B cells of one of these individuals after transformation with EBV (B95.8 strain). Transfection of both HLA-B35 and human beta 2-microglobulin genomic DNA into mouse P815 cells led to high expression of HLA-B molecules; yet, expression of the TU165 epitope was not observed. Furthermore, the EBV-negative cell line BJAB as well as the EBV-infected (P3HR1 strain) line BJAB-HR1K were only weakly reactive, whereas the BJAB-B95.8 cell line was strongly positive. These results indicate that EBV-encoded or -controlled peptide(s) must be bound by HLA-B35 antigens to create the epitope which allows efficient binding of TU165.