RESUMO
Recent advances in immuno-oncology have the potential to transform the practice of medical oncology. Antibodies directed against negative regulators of T-cell function (checkpoint inhibitors), engineered cell therapies and innate immune stimulators, such as oncolytic viruses, are effective in a wide range of cancers. Immune'based therapies have had a clinically meaningful impact on the treatment of advanced melanoma, and the lessons regarding use of single agents and combinations in melanoma may be applicable to the treatment of urological cancers. Checkpoint inhibitors, cytokine therapy and therapeutic vaccines are already showing promise in urothelial bladder cancer, renal cell carcinoma and prostate cancer. Critical areas of future immuno-oncology research include the prospective identification of patients who will respond to current immune-based cancer therapies and the identification of new therapeutic agents that promote immune priming in tumours, and increase the rate of durable clinical responses.
Assuntos
Imunoterapia/métodos , Imunoterapia/tendências , Neoplasias Urológicas/terapia , Humanos , Neoplasias Renais/terapia , Masculino , Seleção de Pacientes , Neoplasias da Próstata/terapia , Neoplasias da Bexiga Urinária/terapiaRESUMO
CAR T-cell product quality and stemness (Tstem) are major determinants of in vivo expansion, efficacy, and clinical response. Prolonged ex vivo culturing is known to deplete Tstem, affecting clinical outcome. YTB323, a novel autologous CD19-directed CAR T-cell therapy expressing the same validated CAR as tisagenlecleucel, is manufactured using a next-generation platform in <2 days. Here, we report the preclinical development and preliminary clinical data of YTB323 in adults with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL; NCT03960840). In preclinical mouse models, YTB323 exhibited enhanced in vivo expansion and antitumor activity at lower doses than traditionally manufactured CAR T cells. Clinically, at doses 25-fold lower than tisagenlecleucel, YTB323 showed (i) promising overall safety [cytokine release syndrome (any grade, 35%; grade ≥3, 6%), neurotoxicity (any grade, 25%; grade ≥3, 6%)]; (ii) overall response rates of 75% and 80% for DL1 and DL2, respectively; (iii) comparable CAR T-cell expansion; and (iv) preservation of T-cell phenotype. Current data support the continued development of YTB323 for r/r DLBCL. SIGNIFICANCE: Traditional CAR T-cell manufacturing requires extended ex vivo cell culture, reducing naive and stem cell memory T-cell populations and diminishing antitumor activity. YTB323, which expresses the same validated CAR as tisagenlecleucel, can be manufactured in <2 days while retaining T-cell stemness and enhancing clinical activity at a 25-fold lower dose. See related commentary by Wang, p. 1961. This article is featured in Selected Articles from This Issue, p. 1949.
Assuntos
Linfoma Difuso de Grandes Células B , Linfoma não Hodgkin , Receptores de Antígenos Quiméricos , Camundongos , Animais , Imunoterapia Adotiva , Técnicas de Cultura de Células , Antígenos CD19RESUMO
GWN323, an agonistic human anti-GITR (glucocorticoid-induced TNFR-related protein) IgG1 antibody, was studied clinically as an immuno-oncology therapeutic agent. A model-based minimum anticipated biological effect level (MABEL) approach integrating in vitro and in vivo data informed dose selection for the first-in-human (FIH) study. Data evaluated included pharmacokinetics (PK) of DTA-1.mIgG2a (mouse surrogate GITR antibody for GWN323), target-engagement pharmacodynamic (PD) marker soluble GITR (sGITR), tumor shrinkage in Colon26 syngeneic mice administered with DTA-1.mIgG2a, cytokine release of GWN323 in human peripheral blood mononuclear cells, and GITR binding affinity. A PK model was developed to describe DTA-1.mIgG2a PK, and its relationship with sGITR was also modeled. Human GWN323 PK was predicted by allometric scaling of mouse PK. Based on the totality of PK/PD modeling and in vitro and in vivo pharmacology and toxicology data, MABEL was estimated to be 3-10 mg once every 3 weeks (Q3W), which informed the starting dose selection of the FIH study. Based on tumor kinetic PK/PD modeling of tumor inhibition by DTA-1.mIgG2a in Colon26 mice and the predicted human PK of GWN323, the biologically active dose of GWN323 was predicted to be 350 mg Q3W, which informed the dose escalation of the FIH study. GWN323 PK from the FIH study was described by a population PK model; the relationship with ex vivo interleukin-2 release, a target-engagement marker, was also modeled. The clinical PK/PD modeling data supported the biological active dose projected from the translational PK/PD modeling in a "learn and confirm" paradigm of model-informed drug development of GWN323.
Assuntos
Antineoplásicos , Neoplasias , Animais , Anticorpos Monoclonais/farmacocinética , Desenvolvimento de Medicamentos , Proteína Relacionada a TNFR Induzida por Glucocorticoide , Humanos , Leucócitos Mononucleares , Camundongos , Modelos BiológicosRESUMO
PURPOSE: This phase II study determined the efficacy of lacnotuzumab added to gemcitabine plus carboplatin (gem-carbo) in patients with advanced triple-negative breast cancer (TNBC). PATIENTS AND METHODS: Female patients with advanced TNBC, with high levels of tumor-associated macrophages not amenable to curative treatment by surgery or radiotherapy were enrolled. Lacnotuzumab was dosed at 10 mg/kg every 3 weeks, ± a dose on cycle 1, day 8. Gemcitabine (1,000 mg/m2) and carboplatin (dose in mg calculated by area under the curve [mg/mL/min] × (glomerular filtration rate [mL/min] + 25 [mL/min]) were dosed every 3 weeks. Treatment continued until unacceptable toxicity, disease progression, or discontinuation by physician/patient. RESULTS: Patients received lacnotuzumab + gem-carbo (n = 34) or gem-carbo (n = 15). Enrollment was halted due to recruitment challenges owing to rapid evolution of the therapeutic landscape; formal hypothesis testing of the primary endpoint was therefore not performed. Median progression-free survival was 5.6 months [90% confidence interval (CI), 4.47-8.64] in the lacnotuzumab + gem-carbo arm and 5.5 months (90% CI, 3.45-7.46) in the gem-carbo arm. Hematologic adverse events were common in both treatment arms; however, patients treated with lacnotuzumab experienced more frequent aspartate aminotransferase, alanine aminotransferase, and creatine kinase elevations. Pharmacokinetic results showed that free lacnotuzumab at 10 mg/kg exhibited a typical IgG pharmacokinetic profile and target engagement of circulating colony-stimulating factor 1 ligand. CONCLUSIONS: Despite successful target engagement and anticipated pharmacokinetic profile, lacnotuzumab + gem-carbo showed comparable antitumor activity to gem-carbo alone, with slightly poorer tolerability. However, the data presented in this article would be informative for future studies testing agents targeting the CSF1-CSF1 receptor pathway in TNBC.
Assuntos
Neoplasias de Mama Triplo Negativas , Anticorpos Monoclonais/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carboplatina , Desoxicitidina/análogos & derivados , Feminino , Humanos , Fator Estimulador de Colônias de Macrófagos , Resultado do Tratamento , Neoplasias de Mama Triplo Negativas/patologia , GencitabinaRESUMO
BACKGROUND: GWN323 is an IgG1 monoclonal antibody (mAb) against the glucocorticoid-induced tumor necrosis factor receptor-related protein. This first-in-human, open-label phase I/Ib study aimed to investigate the safety and tolerability and to identify the recommended doses of GWN323 with/without spartalizumab, an anti-programmed cell death receptor-1 agent, for future studies. Pharmacokinetics, preliminary efficacy and efficacy biomarkers were also assessed. METHODS: Patients (aged ≥18 years) with advanced/metastatic solid tumors with Eastern Cooperative Oncology Group performance status of ≤2 were included. GWN323 (10-1500 mg) or GWN323+spartalizumab (GWN323 10-750 mg+spartalizumab 100-300 mg) were administered intravenously at various dose levels and schedules during the dose-escalation phase. Dose-limiting toxicities (DLTs) were assessed during the first 21 days in a single-agent arm and 42 days in a combination arm. Adverse events (AEs) were graded per National Cancer Institute-Common Toxicity Criteria for Adverse Events V.4.03 and efficacy was assessed using Response Evaluation Criteria in Solid Tumors V.1.1. RESULTS: Overall, 92 patients (single-agent, n=39; combination, n=53) were included. The maximum administered doses (MADs) in the single-agent and combination arms were GWN323 1500 mg every 3 weeks (q3w) and GWN323 750 mg+spartalizumab 300 mg q3w, respectively. No DLTs were observed with single-agent treatment. Three DLTs (6%, all grade ≥3) were noted with combination treatment: blood creatine phosphokinase increase, respiratory failure and small intestinal obstruction. Serious AEs were reported in 30.8% and 34.0%, and drug-related AEs were reported in 82.1% and 77.4% of patients with single-agent and combination treatments, respectively. Disease was stable in 7 patients and progressed in 26 patients with single-agent treatment. In combination arm patients, 1 had complete response (endometrial cancer); 3, partial response (rectal cancer, adenocarcinoma of colon and melanoma); 14, stable disease; and 27, disease progression. GWN323 exhibited a pharmacokinetic profile typical of mAbs with a dose-dependent increase in the pharmacokinetic exposure. Inconsistent decreases in regulatory T cells and increases in CD8+ T cells were observed in the combination arm. Gene expression analyses showed no significant effect of GWN323 on interferon-γ or natural killer-cell signatures. CONCLUSIONS: GWN323, as a single agent and in combination, was well tolerated in patients with relapsed/refractory solid tumors. The MAD was 1500 mg q3w for single-agent and GWN323 750 mg+spartalizumab 300 mg q3w for combination treatments. Minimal single-agent activity and modest clinical benefit were observed with the spartalizumab combination. TRIAL REGISTRATION NUMBER: NCT02740270.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma/tratamento farmacológico , Neoplasias/tratamento farmacológico , Adulto , Idoso , Anticorpos Monoclonais Humanizados/administração & dosagem , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/imunologia , Relação Dose-Resposta a Droga , Feminino , Proteína Relacionada a TNFR Induzida por Glucocorticoide/antagonistas & inibidores , Proteína Relacionada a TNFR Induzida por Glucocorticoide/imunologia , Humanos , Inibidores de Checkpoint Imunológico/administração & dosagem , Masculino , Dose Máxima Tolerável , Pessoa de Meia-IdadeRESUMO
p53 is a transcription factor that plays a central role in guarding the genomic stability of cells through cell-cycle arrest or induction of apoptosis. However, the effects of p53 in antitumor immunity are poorly understood. To investigate the role of p53 in controlling tumor-immune cell cross-talk, we studied murine syngeneic models treated with HDM201, a potent and selective second-generation MDM2 inhibitor. In response to HDM201 treatment, the percentage of dendritic cells increased, including the CD103+ antigen cross-presenting subset. Furthermore, HDM201 increased the percentage of Tbet+Eomes+ CD8+ T cells and the CD8+/Treg ratio within the tumor. These immunophenotypic changes were eliminated with the knockout of p53 in tumor cells. Enhanced expression of CD80 on tumor cells was observed in vitro and in vivo, which coincided with T-cell-mediated tumor cell killing. Combining HDM201 with PD-1 or PD-L1 blockade increased the number of complete tumor regressions. Responding mice developed durable, antigen-specific memory T cells and rejected subsequent tumor implantation. Importantly, antitumor activity of HDM201 in combination with PD-1/PD-L1 blockade was abrogated in p53-mutated and knockout syngeneic tumor models, indicating the effect of HDM201 on the tumor is required for triggering antitumor immunity. Taken together, these results demonstrate that MDM2 inhibition triggers adaptive immunity, which is further enhanced by blockade of PD-1/PD-L1 pathway, thereby providing a rationale for combining MDM2 inhibitors and checkpoint blocking antibodies in patients with wild-type p53 tumors. SIGNIFICANCE: This study provides a mechanistic rationale for combining checkpoint blockade immunotherapy with MDM2 inhibitors in patients with wild-type p53 tumors.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Neoplasias do Colo/tratamento farmacológico , Regulação Neoplásica da Expressão Gênica , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Células Estromais/imunologia , Microambiente Tumoral/imunologia , Proteína Supressora de Tumor p53/antagonistas & inibidores , Animais , Apoptose , Proliferação de Células , Neoplasias do Colo/imunologia , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Quimioterapia Combinada , Feminino , Humanos , Imidazóis/farmacologia , Inibidores de Checkpoint Imunológico/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Nus , Pirimidinas/farmacologia , Pirróis/farmacologia , Células Estromais/efeitos dos fármacos , Células Tumorais Cultivadas , Microambiente Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: No standard treatment exists for platinum-refractory, recurrent/metastatic nasopharyngeal cancer (NPC). This phase II study (NCT02605967) evaluated progression-free survival (PFS) of spartalizumab, an antiprogrammed cell death protein-1 (PD-1) monoclonal antibody, versus chemotherapy, in NPC. PATIENTS AND METHODS: Patients with nonkeratinizing recurrent/metastatic NPC who progressed on/after platinum-based chemotherapy were enrolled. Spartalizumab was dosed 400 mg once every 4 weeks, and chemotherapy was received per investigator's choice. RESULTS: Patients were randomized to receive either spartalizumab (82 patients) or chemotherapy (40 patients). The most common spartalizumab treatment-related adverse events were fatigue (10.3%) and pruritus (9.3%). Median PFS in the spartalizumab arm was 1.9 months versus 6.6 months in the chemotherapy arm (P = 0.915). The overall response rate in the spartalizumab arm was 17.1% versus 35.0% in the chemotherapy arm. Median duration of response was 10.2 versus 5.7 months in the spartalizumab versus chemotherapy arms, respectively. Median overall survival was 25.2 and 15.5 months in the spartalizumab and chemotherapy arms, respectively. Tumor RNA sequencing showed a correlation between response to spartalizumab and IFNγ, LAG-3, and TIM-3 gene expression. CONCLUSIONS: Spartalizumab demonstrated a safety profile consistent with other anti-PD-1 antibodies. The primary endpoint of median PFS was not met; however, median overall survival and median duration of response were longer with spartalizumab compared with chemotherapy.
Assuntos
Anticorpos Monoclonais Humanizados , Neoplasias Nasofaríngeas , Recidiva Local de Neoplasia , Anticorpos Monoclonais Humanizados/efeitos adversos , Tratamento Farmacológico , Humanos , Neoplasias Nasofaríngeas/tratamento farmacológico , Neoplasias Nasofaríngeas/patologia , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/patologiaRESUMO
BACKGROUND: Spartalizumab is a humanized IgG4κ monoclonal antibody that binds programmed death-1 (PD-1) and blocks its interaction with PD-L1 and PD-L2. This phase 1/2 study was designed to assess the safety, pharmacokinetics, and preliminary efficacy of spartalizumab in patients with advanced or metastatic solid tumors. METHODS: In the phase 1 part of the study, 58 patients received spartalizumab, intravenously, at doses of 1, 3, or 10 mg/kg, administered every 2 weeks (Q2W), or 3 or 5 mg/kg every 4 weeks (Q4W). RESULTS: Patients had a wide range of tumor types, most commonly sarcoma (28%) and metastatic renal cell carcinoma (10%); other tumor types were reported in ≤3 patients each. Most patients (93%) had received prior antineoplastic therapy (median three prior lines) and two-thirds of the population had tumor biopsies negative for PD-L1 expression at baseline. The maximum tolerated dose was not reached. The recommended phase 2 doses were selected as 400 mg Q4W or 300 mg Q3W. No dose-limiting toxicities were observed, and adverse events included those typical of other PD-1 antibodies. The most common treatment-related adverse events of any grade were fatigue (22%), diarrhea (17%), pruritus (14%), hypothyroidism (10%), and nausea (10%). Partial responses occurred in two patients (response rate 3.4%); one with atypical carcinoid tumor of the lung and one with anal cancer. Paired tumor biopsies from patients taken at baseline and on treatment suggested an on-treatment increase in CD8+ lymphocyte infiltration in patients with clinical benefit. CONCLUSIONS: Spartalizumab was well tolerated at all doses tested in patients with previously treated advanced solid tumors. On-treatment immune activation was seen in tumor biopsies; however, limited clinical activity was reported in this heavily pretreated, heterogeneous population. The phase 2 part of this study is ongoing in select tumor types. TRIAL REGISTRATION NUMBER: NCT02404441.
Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias/tratamento farmacológico , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados/farmacocinética , Relação Dose-Resposta a Droga , Feminino , Seguimentos , Humanos , Inibidores de Checkpoint Imunológico/farmacocinética , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Neoplasias/imunologia , Neoplasias/patologia , Prognóstico , Receptor de Morte Celular Programada 1/imunologia , Distribuição Tecidual , Adulto JovemRESUMO
Cell migration, a highly complex physiological phenomenon that requires the co-ordinated and tightly regulated function of several proteins, is mediated by a number of signalling pathways. Elucidation of the molecular mechanisms of cell migration impacts our comprehension of numerous cell functions, ranging from development and immune surveillance to angiogenesis and metastasis. The scaffold protein IQGAP1, which binds multiple proteins and regulates their functions, promotes cell motility. Many of the IQGAP1 binding proteins have been implicated in cell migration. In this study, we employed a multifaceted strategy to identify proteins that contribute to IQGAP1-stimulated cell migration. Using specific IQGAP1 point mutant constructs, an interaction with actin was shown to be essential for IQGAP1 to increase cell migration. In contrast, eliminating the binding of Ca(2+)/calmodulin, but not Ca(2+)-free calmodulin, augmented the ability of IQGAP1 to stimulate cell migration. Consistent with these findings, selective inhibition of calmodulin function at the plasma membrane with a specific peptide inhibitor enhanced cell migration mediated by IQGAP1. Interestingly, immunofluorescence staining and confocal microscopy suggest that localization of Cdc42 at the leading edge is not necessary for maximal migration of epithelial cells. Coupled with the observations that Cdc42 and Rac1 contribute to IQGAP1-stimulated cell migration, these data suggest that IQGAP1 serves as a junction to integrate multiple signalling molecules to facilitate cell migration.
Assuntos
Movimento Celular , Proteínas/metabolismo , Proteínas Ativadoras de ras GTPase/metabolismo , Actinas/metabolismo , Calmodulina/metabolismo , Linhagem Celular Tumoral , Humanos , Ligação Proteica , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismoRESUMO
The scaffold protein IQGAP1 integrates signaling pathways and participates in diverse cellular activities. IQGAP1 is overexpressed in a number of human solid neoplasms, but its functional role in tumorigenesis has not been previously evaluated. Here we report that IQGAP1 contributes to neoplastic transformation of human breast epithelial cells. The amount of IQGAP1 in breast carcinoma is greater than that in normal tissue, with highly metastatic breast epithelial cells expressing the highest levels. Overexpression of IQGAP1 enhances proliferation of MCF-7 breast epithelial cells. Reduction of endogenous IQGAP1 by RNA interference impairs both serum-dependent and anchorage-independent growth of MCF-7 cells. Consistent with these in vitro observations, immortalized MCF-7 cells overexpressing IQGAP1 form invasive tumors in immunocompromised mice, whereas tumors derived from MCF-7 cells with stable knockdown of IQGAP1 are smaller and less invasive. In vitro analysis with selected IQGAP1 mutant constructs and a chemical inhibitor suggests that actin, Cdc42/Rac1, and the mitogen-activated protein kinase pathway contribute to the mechanism by which IQGAP1 increases cell invasion. Collectively, our data reveal that IQGAP1 enhances mammary tumorigenesis, suggesting that it may be a target for therapeutic intervention.
Assuntos
Neoplasias da Mama/genética , Mama/citologia , Células Epiteliais/citologia , Proteínas Ativadoras de ras GTPase/fisiologia , Neoplasias da Mama/patologia , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Transformação Celular Neoplásica , Células Epiteliais/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Transdução de Sinais , Proteínas Ativadoras de ras GTPase/genéticaRESUMO
Peritoneal B-1a cells differ from splenic B-2 cells in the molecular mechanisms that control G(0)-S progression. In contrast to B-2 cells, cyclin D2 is up-regulated in a rapid and transient manner in phorbol ester (PMA)-stimulated B-1a cells, whereas cyclin D3 does not accumulate until late G(1) phase. This nonoverlapping expression of cyclins D2 and D3 suggests distinct functions for these proteins in B-1a cells. To investigate the contribution of cyclin D3 in the proliferation of B-1a cells, we transduced p16(INK4a) peptidyl mimetics (TAT-p16) into B-1a cells before cyclin D3 induction to specifically block cyclin D3-cyclin-dependent kinase 4/6 assembly. TAT-p16 inhibited DNA synthesis in B-1a cells stimulated by PMA, CD40L, or LPS as well as endogenous pRb phosphorylation by cyclin D-cyclin-dependent kinase 4/6. Unexpectedly, however, cyclin D3-deficient B-1a cells proliferated in a manner similar to wild-type B-1a cells following PMA or LPS stimulation. This was due, at least in part, to the compensatory sustained accumulation of cyclin D2 throughout G(0)-S progression. Taken together, experiments in which cyclin D3 was inhibited in real time demonstrate the key role this cyclin plays in normal B-1a cell mitogenesis, whereas experiments with cyclin D3-deficient B-1a cells show that cyclin D2 can compensate for cyclin D3 loss in mutant mice.
Assuntos
Subpopulações de Linfócitos B/citologia , Proliferação de Células , Ciclinas/antagonistas & inibidores , Ciclinas/deficiência , Ciclinas/fisiologia , Inibidores do Crescimento , Sequência de Aminoácidos , Animais , Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/metabolismo , Ciclina D2 , Ciclina D3 , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 4 Dependente de Ciclina/genética , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/genética , Ciclinas/genética , Produtos do Gene tat/antagonistas & inibidores , Produtos do Gene tat/genética , Marcação de Genes , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Dados de Sequência Molecular , Peptídeos/antagonistas & inibidores , Peptídeos/genética , Fosforilação , Proteína do Retinoblastoma/metabolismo , Transdução GenéticaRESUMO
The bioenergetic response of B lymphocytes is subject to rapid changes following antigen encounter in order to provide ATP and anabolic precursors necessary to support growth. However, the pathways involved in glucose acquisition and metabolism are unknown. We find that B lymphocytes rapidly increase glucose uptake and glycolysis following B-cell antigen receptor (BCR) crosslinking. Inhibition of glycolysis blocks BCR-mediated growth. Prior to S-phase entry, glucose metabolism shifts from primarily glycolytic to include the pentose phosphate pathway. BCR-induced glucose utilization is dependent upon phosphatidylinositol 3-kinase (PI-3K) activity as evidenced by inhibition of glucose uptake and glycolysis with LY294002 treatment of normal B cells and impaired glucose utilization in B cells deficient in the PI-3K regulatory subunit p85alpha. Activation of Akt is sufficient to increase glucose utilization in B cells. We find that glucose utilization is inhibited by coengagement of the BCR and FcgammaRIIB, suggesting that limiting glucose metabolism may represent an important mechanism underlying FcgammaRIIB-mediated growth arrest. Taken together, these findings demonstrate that both growth-promoting BCR signaling and growth-inhibitory FcgammaRIIB signaling modulate glucose energy metabolism. Manipulation of these pathways may prove to be useful in the treatment of lymphoproliferative disorders, wherein clonal expansion of B lymphocytes plays a role.
Assuntos
Linfócitos B/metabolismo , Processos de Crescimento Celular , Glucose/metabolismo , Glicólise/fisiologia , Fosfatidilinositol 3-Quinases/fisiologia , Receptores de Antígenos/fisiologia , Animais , Antígenos CD/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Receptores de IgG/metabolismo , Transdução de SinaisRESUMO
Introduction of exogenous DNA into mammalian cells represents a powerful approach for manipulating signal transduction. The available techniques, however, are limited by low transduction efficiency and low cell viability after transduction. Here we report a highly efficient molecular delivery technique, named nanotube spearing, based on the penetration of nickel-embedded nanotubes into cell membranes by magnetic field driving. DNA plasmids containing the enhanced green fluorescent protein (EGFP) sequence were immobilized onto the nanotubes, and subsequently speared into targeted cells. We have achieved an unprecedented high transduction efficiency in Bal17 B-lymphoma, ex vivo B cells and primary neurons with high viability after transduction. This technique may provide a powerful tool for highly efficient gene transfer into a variety of cells, especially the hard-to-transfect cells.
Assuntos
DNA/administração & dosagem , DNA/genética , Sistemas de Liberação de Medicamentos/métodos , Campos Eletromagnéticos , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Transfecção/métodos , Animais , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/efeitos da radiação , Humanos , Nanotubos de Carbono/efeitos da radiaçãoRESUMO
The cAMP-response element-binding protein (CREB) is activated by phosphorylation on Ser-133 and plays a key role in the proliferative and survival responses of mature B cells to B cell receptor (BCR) signaling. The signal link between the BCR and CREB activation depends on a phorbol ester (phorbol 12-myristate 13-acetate)-sensitive protein kinase C (PKC) activity and not protein kinase A or calmodulin kinase; however, the identity and role of the PKC(s) activity has not been elucidated. We found the novel PKCdelta (nPKCdelta) activator bistratene A is sufficient to induce CREB phosphorylation in murine splenic B cells. The pharmacological inhibitor Gö6976, which targets conventional PKCs and PKCmu, has no effect on CREB phosphorylation, whereas the nPKCdelta inhibitor rottlerin blocks CREB phosphorylation following BCR cross-linking. Bryostatin 1 selectively prevents nPKCdelta depletion by phorbol 12-myristate 13-acetate when coapplied, coincident with protection of BCR-induced CREB phosphorylation. Ectopic expression of a kinase-inactive nPKCdelta blocks BCR-induced CREB phosphorylation in A20 B cells. In addition, BCR-induced CREB phosphorylation is significantly diminished in nPKCdelta-deficient splenic B cells in comparison with wild type mice. Consistent with the essential role for Bruton's tyrosine kinase and phospholipase Cgamma2 in mediating PKC activation, Bruton's tyrosine kinase- and phospholipase Cgamma2-deficient B cells display defective CREB phosphorylation by the BCR. We also found that p90 RSK directly phosphorylates CREB on Ser-133 following BCR cross-linking and is positioned downstream of nPKCdelta. Taken together, these results suggest a model in which BCR engagement leads to the phosphorylation of CREB via a signaling pathway that requires nPKCdelta and p90 RSK in mature B cells.
Assuntos
Linfócitos B/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Proteína Quinase C/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Acetamidas/farmacologia , Acetofenonas/farmacologia , Animais , Benzopiranos/farmacologia , Sítios de Ligação , Western Blotting , Briostatinas , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Carbazóis/farmacologia , Divisão Celular , Reagentes de Ligações Cruzadas/farmacologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Indóis/farmacologia , Lactonas/farmacologia , Macrolídeos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Mitógenos , Fosforilação , Regiões Promotoras Genéticas , Isoformas de Proteínas , Proteína Quinase C-delta , Estrutura Terciária de Proteína , Piranos/farmacologia , Proteínas Quinases S6 Ribossômicas 90-kDa/metabolismo , Serina/química , Transdução de Sinais , Compostos de Espiro/farmacologia , Acetato de Tetradecanoilforbol , Fatores de TempoRESUMO
IQGAP1 is a multi-domained protein that integrates signaling of the Rho family GTPase Cdc42 with regulation of the cytoskeleton. Using SPOT analysis and in vitro peptide competition assays we have identified a 24 amino acid region of IQGAP1 that is necessary for Cdc42 binding. Both in vitro and in vivo analyses reveal that deletion of this sequence abolishes binding of IQGAP1 to Cdc42. In addition, the ability of IQGAP1 to increase the amount of active Cdc42 in cells is abrogated upon removal of this region. An IQGAP1 mutant lacking the Cdc42 binding site mislocalizes to the cell periphery. These observations specifically define a short sequence of IQGAP1 that is required for its interaction with Cdc42 and demonstrate that Cdc42 binding is necessary for the normal subcellular distribution of IQGAP1.
Assuntos
Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas Ativadoras de ras GTPase , Animais , Células COS , Proteínas de Transporte/genética , Humanos , Testes de Precipitina , Estrutura Terciária de Proteína , Deleção de Sequência , Células Tumorais CultivadasRESUMO
The Ras-GAP related protein IQGAP1 binds several proteins, including actin, calmodulin, E-cadherin and the Rho family GTPase Cdc42. To gain insight into its in vivo function, IQGAP1 was overexpressed in mammalian cells. Transfection of IQGAP1 significantly increased the levels of active, GTP-bound Cdc42, resulting in the formation of peripheral actin microspikes. By contrast, transfection of an IQGAP1 mutant lacking part of the GAP-related domain (IQGAP1deltaGRD) substantially decreased the amount of GTP-bound Cdc42 in cell lysates. Consistent with these findings, IQGAP1DeltaGRD blocked Cdc42 function in cells that stably overexpress constitutively active Cdc42 and abrogated the effect of bradykinin on Cdc42. In cells transfected with IQGAP1deltaGRD, bradykinin was unable to activate Cdc42, translocate Cdc42 to the membrane fraction, or induce filopodia production. IQGAP1deltaGRD transfection altered cellular morphology, producing small, round cells that closely resemble Cdc42-/- cells. Some insight into the mechanism was provided by in vitro analysis, which revealed that IQGAP1deltaGRD increased the intrinsic GTPase activity of Cdc42, thereby increasing the amount of inactive, GDP-bound Cdc42. These data imply that IQGAP1 has a crucial role in transducing Cdc42 signaling to the cytoskeleton.
Assuntos
Proteínas de Transporte/metabolismo , Citoesqueleto/fisiologia , Transdução de Sinais/fisiologia , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas Ativadoras de ras GTPase , Sequência de Aminoácidos , Animais , Neoplasias da Mama , Proteínas de Transporte/genética , Bovinos , Linhagem Celular , Feminino , Guanosina Trifosfato/metabolismo , Humanos , Dados de Sequência Molecular , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/genética , Schizosaccharomyces/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Transfecção , Proteína cdc42 de Ligação ao GTP/genéticaRESUMO
The dynamic processes of cell migration and invasion are largely coordinated by Rho family GTPases. The scaffolding protein IQGAP1 binds to Cdc42, increasing the amount of active Cdc42 both in vitro and in cells. Here we show that overexpression of IQGAP1 in mammalian cells enhances cell migration in a Cdc42- and Rac1-dependent manner. Importantly, cell motility was significantly decreased both by knock down of endogenous IQGAP1 using small interfering RNA and by transfection of a dominant negative IQGAP1 construct, IQGAP1DeltaGRD. Cell invasion was similarly altered by manipulating intracellular IQGAP1 concentrations. Moreover, invasion mediated by constitutively active Cdc42 was attenuated by IQGAP1DeltaGRD. Thus, IQGAP1 has a fundamental role in cell motility and invasion.
Assuntos
Proteínas de Transporte/fisiologia , Proteínas Ativadoras de ras GTPase , Animais , Western Blotting , Linhagem Celular Tumoral , Movimento Celular , Genes Dominantes , Glutationa Transferase/metabolismo , Humanos , Imuno-Histoquímica , Camundongos , Microscopia Confocal , Células NIH 3T3 , Invasividade Neoplásica , Plasmídeos/metabolismo , RNA Interferente Pequeno/metabolismo , Fatores de Tempo , Transfecção , Cicatrização , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismoRESUMO
Ca(2+) and calmodulin (CaM) play a critical role in proliferation and viability of a wide variety of cells, including prostate cancer cells. We examined two prostate cancer cell lines, androgen-sensitive LNCaP and androgen-independent PC-3. Proliferation of LNCaP cells was six to eight times more sensitive to the inhibitory effect of the CaM antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) than were PC-3 cells. Because LNCaP cell proliferation is sensitive to stimulation by androgen, we assessed the physical and functional interaction between androgen receptor (AR) and CaM. We observed tight binding of AR to CaM when LNCaP cell extracts were subjected to CaM-affinity column chromatography. AR binding to CaM was Ca(2+)-dependent and was inhibited by pretreatment of the cell extracts with W-7. Using immunofluorescence staining and confocal microscopy, we demonstrated colocalization of AR and CaM in the nucleus of LNCaP cells. Furthermore, the functional relevance of AR-CaM interactions in intact cells was revealed by the observation that W-7 was as effective as Casodex, an antiandrogen, in blocking AR-regulated expression of prostate-specific antigen in LNCaP cells. AR seems to interact with CaM directly because purified human AR could bind to CaM-agarose, and CaM could be detected in AR-immunoprecipitate prepared from purified soluble proteins. These studies provide direct evidence for physical and functional interaction between AR and CaM and suggest the potential usefulness of CaM antagonists in blocking AR activity in prostate cancer.