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1.
Am J Gastroenterol ; 116(Suppl 1): S8, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37461950

RESUMO

BACKGROUND: Ozanimod, an oral sphingosine 1-phosphate (S1P) receptor modulator selectively targeting S1P1 and S1P5, demonstrated superior efficacy and safety vs placebo for up to 52 weeks in adults with moderately to severely active ulcerative colitis (UC) in a phase 3 study (True North). In this post-hoc analysis, we evaluated the impact of prior biologic exposure on response to ozanimod. METHODS: True North consisted of two cohorts. In cohort 1, patients with UC received double-blind treatment with once-daily ozanimod 0.92 mg (equivalent to ozanimod HCl 1 mg) or placebo. In cohort 2, patients received open-label once daily ozanimod 0.92 mg. Ozanimod responders after a 10-week induction were re-randomized to double-blind maintenance with ozanimod 0.92 mg or placebo through week 52. Outcomes based on prior biologic exposure (biologic-naïve, 1 biologic, and 2+ biologics) and prior biologic type (anti-tumor necrosis factor [TNF] agents, vedolizumab, or both) were analyzed for clinical remission, clinical response, endoscopic improvement, and mucosal healing. Patients exposed to only a JAK inhibitor were excluded from the analysis. RESULTS: A total of 992 patients (n = 213 placebo and n = 426 ozanimod in cohort 1, n = 353 ozanimod in cohort 2) were included in the analysis for induction; 616 were biologic-naïve, 162 had exposure to 1 biologic, and 214 were exposed to 2 or more biologics. At baseline, biologic-exposed patients had more prior corticosteroid use, longer disease duration, and more extensive disease than biologic-naïve patients. During induction, greater therapeutic effects of ozanimod were generally seen in biologic-naïve vs biologic-exposed patients, and ozanimod-treated patients had greater responses on nearly all reported endpoints at week 10 (cohort 1). Clinical remission was achieved in 23% vs 6.6% of patients on ozanimod vs placebo who were biologic naïve, 17.2% vs 8.3% on 1 prior biologic, and 3.7% vs 2.5% on 2 or more biologics. Clinical response was reached in 53% vs 28% of patients on ozanimod vs placebo who were biologic naïve, 50% vs 33% on 1 biologic, and 27% vs 15% on 2 or more biologics. During maintenance, ozanimod-treated patients had greater responses on all endpoints versus placebo, with similar proportions of patients achieving clinical response to ozanimod regardless of prior biologic exposure (61% for biologic naïve, 60% for 1 biologic, and 55% for 2 or more biologics). At week 52, the proportion of patients on ozanimod with clinical remission was similar in the 1-biologic and 2+-biologic exposure groups (28% and 26%, respectively), and proportions of patients on ozanimod with endoscopic improvement and mucosal healing were similar for the 1-biologic and biologic-naïve groups (47% and 50%, 30%, and 33%, respectively). Among patients with inadequate response to prior anti-TNF agents, vedolizumab, or both at baseline, treatment effects favored ozanimod vs placebo on these endpoints in all three groups during both induction and maintenance. CONCLUSION: Ozanimod improved clinical, endoscopic, and histologic outcomes in both biologic-exposed and -naïve patients. Patients with prior biologic use may require additional time to respond to treatment. Outcomes were improved with ozanimod regardless of prior use of anti-TNF agents and vedolizumab.

2.
Am J Gastroenterol ; 116(Suppl 1): S9, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37461954

RESUMO

BACKGROUND: True North is a phase 3, randomized, double-blind, placebo-controlled trial conducted at 285 sites in 30 countries (NCT02435992). Treatment with once-daily ozanimod (an oral sphingosine 1-phosphate [S1P] receptor modulator selectively targeting S1P1 and S1P5) in patients with moderately-to-severely active ulcerative colitis (UC) showed significant improvements in primary and all key secondary endpoints. Here we report findings on the consistency of clinical and endoscopic endpoints in the global and North American population. METHODS: In True North, patients received either double-blind treatment with ozanimod 0.92 mg (equivalent to ozanimod HCl 1 mg) or matching placebo, or open-label ozanimod 0.92 mg over a 10-week induction period. Patients with clinical response to ozanimod at Week 10 were re-randomized 1:1 to receive double-blind maintenance treatment with ozanimod 0.92 mg or placebo through Week 52. The primary endpoint was proportion of patients in clinical remission at Weeks 10 and 52; key secondary endpoints included clinical response and endoscopic improvement. The global population included 1012 patients who received at least 1 dose of study medication during induction, and 457 who received at least 1 dose of study medication during maintenance. Here, we examine the results from the patients in the North American sites. RESULTS: A total of 247 patients were enrolled in North America, of which 167 received double-blind ozanimod (n=107) or placebo (n=60) during induction. At baseline, 41.1% and 48.3% of patients in the ozanimod and placebo groups, respectively, had previously received a biologic treatment for UC. At Week 10, 15.9% and 3.3% of patients in the ozanimod and placebo groups, respectively, achieved clinical remission. In addition, 46.7% and 15.0% achieved clinical response and 26.2% and 10.0% achieved endoscopic improvement in the ozanimod and placebo groups, respectively. In patients with prior exposure to tumor necrosis factor inhibitor (TNFi), the proportion with clinical response favored ozanimod (35.7%) vs placebo (11.5%), while the proportion with clinical remission and endoscopic improvement did not favor ozanimod. In patients with no prior TNFi exposure, greater responses were seen with ozanimod vs placebo for all 3 endpoints. During maintenance, 105 patients from North America were re-randomized to treatment with ozanimod (n=56) or placebo (n=49). At Week 52, 39.3% and 12.2% of patients in the ozanimod and placebo groups, respectively, achieved clinical remission. In addition, 58.9% and 26.5% achieved clinical response and 50.0% and 16.3% achieved endoscopic improvement in the ozanimod and placebo groups, respectively. The proportion of patients with clinical remission, clinical response, and endoscopic improvement favored ozanimod vs placebo regardless of prior TNFi use. These outcomes from the North American population are generally consistent with those previously reported from the global population. CONCLUSION: In this post-hoc analysis, consistent with the global population, ozanimod treatment for up to 52 weeks in North American patients with moderately-to-severely active UC showed benefits on clinical and endoscopic endpoints.

3.
Am J Gastroenterol ; 116(Suppl 1): S9-S10, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37461957

RESUMO

BACKGROUND: Ozanimod, an oral sphingosine 1-phosphate (S1P) receptor modulator that selectively targets S1P1 and S1P5, is approved in the US for treating moderately to severely active ulcerative colitis (UC) and in multiple countries for treating relapsing forms of multiple sclerosis (MS). In a Phase 1 study of ozanimod in healthy participants, first-dose cardiac effects were mitigated with gradual dose escalation. Based on these results, an initial 7-day ozanimod dose escalation regimen was implemented in all Phase 2 and 3 UC and MS trials. The objective of this analysis was to evaluate the number of patients who were excluded from ozanimod treatment due to contraindications of pre-existing cardiac disorders and to evaluate the incidence of cardiac-related treatment-emergent adverse events (TEAEs) following first-dose ozanimod administration in all patients and patients with a history of non-exclusionary cardiac disorders in the UC and MS clinical trials. METHODS: For UC, the analysis included pooled data from the Phase 2 Touchstone (NCT01647516) and Phase 3 True North (NCT02435992) trials. For MS, the analysis included pooled data from the Phase 3 Radiance (NCT02047734) and Sunbeam (NCT02294058) trials. Patients with clinically relevant cardiac conditions or clinically significant electrocardiogram (ECG) disorders were excluded from the trials. On Day 1, all patients received ozanimod 0.23 mg (equivalent to ozanimod HCl 0.25 mg). Day 1 cardiac monitoring included collection of vital signs (including heart rate) prior to dosing and hourly for at least 6 hours after dosing, and ECG prior to dosing and at Hour 6 after dosing. RESULTS: Among patients screened, 26/2178 (1.2%) in the UC studies and 47/3351 (1.4%) in the MS studies were excluded due to protocol-defined pre-existing cardiac disorders. Of 496 patients who received ozanimod in the UC studies, 1 (0.2%) experienced a cardiac-related TEAE on Day 1 (asymptomatic bradycardia). Of 1774 patients who received ozanimod in the MS studies, 11 (0.6%) experienced a cardiac-related TEAE on Day 1. In both the UC and MS studies, no cases of second- or third-degree AV block were observed. A decrease in mean heart rate from baseline (UC, 0.7 bpm; MS, 1.2 bpm) was observed at first-dose that reached a nadir at Hour 5 and returned to baseline by Hour 6. Among 496 patients with UC who received ozanimod, 34 (6.9%) had a known history of cardiac disorders, of whom 1 experienced a cardiac-related TEAE on Day 1 (asymptomatic bradycardia). Among the 1774 patients with MS who received ozanimod, 96 (5.4%) had a known history of cardiac disorders, of whom 2 experienced symptomatic bradycardia on Day 1. CONCLUSION: In clinical trials of ozanimod, the number of patients with UC or MS who failed screening because of exclusionary cardiac disorders was low. Most patients with a history of cardiac disorders who were enrolled in ozanimod clinical trials did not have Day 1 cardiac events, and the events that occurred were manageable.

4.
J Med Econ ; 27(sup3): 1-8, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38488887

RESUMO

AIMS: To estimate, in the setting of recurrent or metastatic nasopharyngeal carcinoma (R/M NPC) for an assumed 1,207 incident US cases in 2024, (1) the cost-efficiency of a toripalimab-gemcitabine-cisplatin regimen compared to a similar pembrolizumab regimen; and (2) the budget-neutral expanded access to additional toripalimab cycles and regimens afforded by the accrued savings. METHODS: Simulation modeling utilized two cost inputs (wholesale acquisition cost (WAC) at market entry and an ex ante toripalimab price point of 80% of pembrolizumab average sales price (ASP)) and drug administration costs over 1 and 2 years of treatment with treatment rates ranging from 45% to 90%. In the absence of trial data for pembrolizumab-gemcitabine-cisplatin in R/M NPC, it is assumed that such a regimen would be comparable to toripalimab-gemcitabine-cisplatin in efficacy and safety. RESULTS: In the models utilizing the WAC, toripalimab saves $2,223 per patient per cycle and $40,014 over 1 year of treatment ($77,805 over 2 years). Extrapolated to the 1,207-patient panel, estimated 1-year savings range from $21,733,702 (45% treatment rate) to $43,467,404 (90% rate). Reallocating these savings permits budget-neutral expanded access to an additional 2,359 (45% rate) to 4,717 (90% rate) toripalimab maintenance cycles or to an additional 126 (45% rate) to 252 (90%) full 1-year toripalimab regimens with all agents. Two-year savings range from $42,259,976 (45% rate) to $84,519,952 (90% rate). Reallocating these efficiencies provides expanded access, ranging from an additional 4,586 (45% rate) to 9,172 (90% rate) toripalimab cycles or to an additional 128-257 full 2-year toripalimab regimens. The ex ante ASP model showed similar results. CONCLUSION: This simulation demonstrates that treatment with toripalimab generates savings that enable budget-neutral funding for up to an additional 252 regimens with toripalimab-gemcitabine-cisplatin for one full year, the equivalent of approximately 21% of the 2024 incident cases of R/M NPC in the US.


An estimated 1,207 patients will be diagnosed with late-stage nasopharyngeal cancer in the US in 2024. Toripalimab is a novel PD-1 inhibitor drug approved by the US Food and Drug Administration on October 27, 2023 as first-line treatment for patients with recurrent or metastatic nasopharyngeal cancer when used in combination with gemcitabine and cisplatin. We conducted economic evaluations of the costs of this toripalimab regimen versus the costs of a similar regimen with the PD-1 inhibitor pembrolizumab. Our simulation models used two pricing scenarios: the wholesale acquisition cost (WAC) or "list price" at market entry and, as no average sales price (ASP) will be available for toripalimab for several quarters, an estimated toripalimab price point of 80% of the pembrolizumab ASP. We compared the savings in each scenario when between 45% and 90% of the 1,207 patients are treated with the toripalimab regimen. We then evaluated how these savings could be re-allocated, on a budget-neutral basis and without requiring extra cash outlays, to provide more patients with access to toripalimab treatment; specifically, how many toripalimab doses and how many full toripalimab regimens could be purchased to provide more patients with treatment. We found that, if 90% of new cases of recurrent or metastatic nasopharyngeal cancer were treated with toripalimab over 1 year, these savings are enough to purchase up to 4,717 additional doses on a budget-neutral basis, which could provide up to an additional 252 newly diagnosed patients with 1 year of treatment with toripalimab. In combination with gemcitabine and cisplatin, toripalimab can markedly improve access to care for patients with recurrent or metastatic nasopharyngeal cancer in a cost-responsible way.


Assuntos
Anticorpos Monoclonais Humanizados , Gencitabina , Neoplasias Nasofaríngeas , Humanos , Cisplatino/uso terapêutico , Carcinoma Nasofaríngeo/tratamento farmacológico , Inibidores de Checkpoint Imunológico/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Recidiva Local de Neoplasia/tratamento farmacológico , Desoxicitidina/uso terapêutico , Neoplasias Nasofaríngeas/tratamento farmacológico , Neoplasias Nasofaríngeas/patologia
5.
J Med Econ ; 27(sup3): 24-33, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39016841

RESUMO

AIMS: To estimate in a panel of patients with locally advanced/metastatic nonsquamous non-small cell lung cancer (NSCLC) treated with a programmed death receptor-1 inhibitor in the US in 2024 (1) the cost-efficiency of toripalimab regimens compared to pembrolizumab regimens; and (2) the budget-neutral expanded access to additional toripalimab cycles and regimens from accrued savings. METHODS: Simulation modeling of toripalimab + pemetrexed + carboplatin in nonsquamous NSCLC to a similar pembrolizumab regimen in a panel of 49,647 patients; utilizing two cost inputs (wholesale acquisition cost (WAC) at market entry and an estimated ex ante toripalimab price point of 80% of pembrolizumab average sales price (ASP)) plus administration costs over one and two years of treatment with treatment rates from 1%-10%. Scenario analyses with treatment durations equivalent to toripalimab and pembrolizumab trials' median PFS were also conducted. RESULTS: In the WAC-based models, toripalimab saves $2,223 per patient per cycle and $40,014 over 1 year of treatment ($77,805 over 2 years). Extrapolated to the 49,647-patient panel, estimated 1-year savings range from $19,865,840 (1% treatment rate) to $198,658,399 (10% rate). Reallocating these savings permits budget-neutral expanded access to an additional 1,753 (1% rate) to 17,533 (10% rate) toripalimab maintenance cycles or to an additional 97 (1% rate) to 972 (10%) full 1-year toripalimab regimens with all agents. Two-year savings range from $38,628,022 (1% rate) to $386,280,221 (10%). Reallocating these efficiencies provides expanded access ranging from 3,409 (1% rate) to 34,093 (10%) additional toripalimab cycles or to 97 to 973 full 2-year regimens. The ex ante ASP model showed similar results as did the scenario analyses but at a lower magnitude than the base case. CONCLUSION: Toripalimab generates significant savings that enable budget-neutral funding for up to 17,533 [34,093] additional maintenance cycles over one year [two years] with toripalimab + pemetrexed in nonsquamous NSCLC, or 972 [973] full one-year [two-year] regimens.


An estimated 49,647 patients with advanced or metastatic nonsquamous non-small cell lung cancer (NSCLC) will be treated with a PD-1 inhibitor in the US in 2024. Toripalimab, a PD-1 inhibitor recently approved by the US Food and Drug Administration for the treatment of nasopharyngeal carcinoma, has also been found to be beneficial in patients with nonsquamous NSCLC when used in combination with chemotherapy. We conducted an economic simulation of the costs of toripalimab + pemetrexed + carboplatin versus the costs of a similar regimen with the PD-1 inhibitor pembrolizumab in the treatment of patients with nonsquamous NSCLC. Our simulation models used two US cost inputs for toripalimab: the wholesale acquisition cost or "list price" at market entry and, as no average sales price (ASP) will be available for toripalimab for several quarters, a hypothetical toripalimab price point of 80% of the pembrolizumab ASP. We compared the savings in each scenario when between 1% and 10% of the 49,647 nonsquamous NSCLC patients are treated with the toripalimab regimen. We then evaluated how these savings could be re-allocated, without requiring extra funding, to provide more patients with access to toripalimab treatment on a budget-neutral basis. We found that, if 1% of new cases of advanced/metastatic nonsquamous NSCLC were treated with toripalimab for 1 year, these savings are enough to purchase up to 1,753 additional toripalimab maintenance cycles; or these savings could provide up to an additional 97 patients with full one-year regimens with all agents (toripalimab + chemotherapy). If 10% of new cases were treated with toripalimab for 1 year, the savings are enough to purchase up to 17,533 additional toripalimab maintenance cycles; or these savings could provide up to an additional 972 patients with full one-year regimens with all agents.


Assuntos
Anticorpos Monoclonais Humanizados , Protocolos de Quimioterapia Combinada Antineoplásica , Carcinoma Pulmonar de Células não Pequenas , Análise Custo-Benefício , Neoplasias Pulmonares , Pemetrexede , Anticorpos Monoclonais Humanizados/uso terapêutico , Anticorpos Monoclonais Humanizados/economia , Humanos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/economia , Pemetrexede/uso terapêutico , Pemetrexede/economia , Carboplatina/uso terapêutico , Carboplatina/economia , Carboplatina/administração & dosagem , Inibidores de Checkpoint Imunológico/uso terapêutico , Inibidores de Checkpoint Imunológico/economia , Orçamentos , Modelos Econométricos , Feminino
6.
J Med Econ ; 27(sup3): 9-23, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39016811

RESUMO

AIM: To estimate the budget impact of adding a toripalimab regimen as a treatment option to the existing pembrolizumab regimen, both including gemcitabine and cisplatin, in untreated recurrent/metastatic nasopharyngeal carcinoma (R/M NPC) using the published wholesale acquisition cost (WAC) and average sales price (ASP). METHODS: Budget impact analysis comparing a treatment mix "without" versus "with" the toripalimab regimen in the US eligible annual incident R/M NPC population, a 3-year time horizon, toripalimab/pembrolizumab market splits of 60/40 (Y1) and 80/20 (Y2/3), and medication adjustments for discontinuation or progression. Cost inputs included drugs, administration, and adverse event (AE) management. The models were replicated for a hypothetical 1-million-member health plan in which costs per-member-per-month (PMPM) and per-member-per-year (PMPY) were estimated. One-way (OWSA) and probabilistic sensitivity analyses (PSA) as well as scenario analyses were performed. RESULTS: In the "without" scenario, the 3-year WAC-based costs for the pembrolizumab regimen total $1,449,695,333 ($1,305,632,448 for treatment and $144,062,885 for managing AEs). In the "with" scenario, total 3-year costs for pembrolizumab decline to $380,012,135 with toripalimab adding $885,505,900 ($779,206,567 for treatment and $106,299,333 for AE management). Annual net savings range from $46,526,152 in 2024 to $71,194,214 in 2026, for 3-year savings of $184,177,298. Associated net savings in a 1-million-member health plan are $543,068 over 3 years with savings of $0.045 PMPM and $0.543 PMPY. The ASP-based model shows similar patterns with 3-year net savings of $174,235,983 in the US incident population and savings of $0.043 PMPM and $0.514 PMPY in a 1-million-member health plan. The PSA support base case findings; OWSA and scenario analyses reveal how parameter variability impacts results. CONCLUSION: Savings between $174 million and $184 million can be achieved from treating 60% of R/M NPC patients in year 1 and 80% in years 2 and 3 with the toripalimab regimen over a similar pembrolizumab regimen.


Toripalimab, a human monoclonal anti-body that targets PD-1, was recently approved by the US Food and Drug Administration (FDA) for the first-line treatment of adults with metastatic or recurrent, locally advanced nasopharyngeal carcinoma (NPC), in combination with gemcitabine and cisplatin. We evaluated how much it would cost a payor to cover the FDA-approved toripalimab plus gemcitabine and cisplatin regimen (the toripalimab regimen) to a non-FDA-approved pembrolizumab plus gemcitabine and cisplatin regimen (the pembrolizumab regimen). With no trial data available for such pembrolizumab regimen, we assumed that it would be comparable to the toripalimab regimen in efficacy and safety. Our model adopted a 3-year time horizon and assumed a 60/40 market share split in year 1 and an 80/20 market split in years 2 and 3. It included two US cost inputs: the wholesale acquisition cost (WAC) or "list price" at market entry and, as no average sales price (ASP) will be available for toripalimab for several quarters, a toripalimab price point of 80% of the pembrolizumab ASP. We adjusted for patients whose cancer progressed or who discontinued treatment to determine the number of fully-treated-patient-equivalents. We found that treating 60% of NPC patients in year 1 and 80% in years 2 and 3 with the toripalimab regimen instead of the pembrolizumab regimen generates, for the entire adjusted patient population, savings ranging from $174 million when using ASP to $184 million when using WAC.


Assuntos
Anticorpos Monoclonais Humanizados , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas , Anticorpos Monoclonais Humanizados/uso terapêutico , Anticorpos Monoclonais Humanizados/economia , Humanos , Carcinoma Nasofaríngeo/tratamento farmacológico , Carcinoma Nasofaríngeo/economia , Neoplasias Nasofaríngeas/tratamento farmacológico , Neoplasias Nasofaríngeas/economia , Neoplasias Nasofaríngeas/patologia , Recidiva Local de Neoplasia/tratamento farmacológico , Análise Custo-Benefício , Protocolos de Quimioterapia Combinada Antineoplásica/economia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Antineoplásicos Imunológicos/economia , Antineoplásicos Imunológicos/uso terapêutico , Inibidores de Checkpoint Imunológico/uso terapêutico , Inibidores de Checkpoint Imunológico/economia , Desoxicitidina/análogos & derivados , Desoxicitidina/uso terapêutico , Desoxicitidina/economia , Modelos Econométricos , Orçamentos , Gencitabina , Metástase Neoplásica , Estados Unidos , Gastos em Saúde/estatística & dados numéricos
7.
BMC Mol Biol ; 6: 7, 2005 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-15790393

RESUMO

BACKGROUND: Receptor activity modifying protein-1 (RAMP-1) is a single transmembrane-domain protein required for the functional expression of calcitonin gene-related peptide (CGRP) receptors. To date, little is known about the molecular mechanism(s) that activate/inhibit RAMP-1 gene expression. Such mechanism(s) are likely to play a major role in modulating the responsiveness of tissues to CGRP. RESULTS: To initiate studies on the transcriptional regulation of the mouse RAMP-1 gene, RAMP-1 transcriptional initiation sites were mapped in a variety of tissues. Analysis of RAMP-1 expression in C2C12 myoblasts demonstrated that RAMP-1 mRNA is expressed at greatest levels in confluent myoblasts verses non-confluent and fused myoblasts. Transfection of confluent C2C12 myoblasts and NIH 3T3 cells with RAMP-1 promoter/luciferase deletion constructs revealed that 4.7 kb of RAMP-1 5' flanking region demonstrated optimal promoter activity while 343 bp of 5' flanking region was defined as a minimal RAMP-1 promoter. In non-RAMP-1 expressing HEK293 cells, constructs containing 4.7 kb to 782 bp of RAMP-1 5' flanking region were transcriptionally inactive. However, deletion of sequences -782 to -343 activated RAMP-1 promoter activity. CONCLUSION: These findings suggest that tissue specificity of RAMP-1 gene expression is mediated by a negative acting transcription factor that represses RAMP-1 gene expression in non-RAMP-1 expressing tissues. This transcription factor is therefore likely to play an important role in modulating the responsiveness of tissues to CGRP.


Assuntos
Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Regiões Promotoras Genéticas/genética , Sítio de Iniciação de Transcrição , Região 5'-Flanqueadora/genética , Animais , Sequência de Bases , Linhagem Celular Tumoral/metabolismo , Clonagem Molecular , Camundongos , Dados de Sequência Molecular , Fibras Musculares Esqueléticas/metabolismo , Mioblastos/metabolismo , Proteínas Modificadoras da Atividade de Receptores , Proteínas Repressoras/metabolismo , Análise de Sequência de DNA , Transfecção
8.
Cancer Cell Int ; 3(1): 6, 2003 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-12747809

RESUMO

BACKGROUND: The peptide hormone calcitonin (CT) can significantly effect the proliferation rate of CT receptor (CTR) positive human cancer cells. We wish to identify additional human cancers expressing CTRs and assay the effects of CT on their growth rates and signal transduction pathways. RESULTS: The expression of the human calcitonin receptor (hCTR) gene in the chronic myelogenous leukemia cell line K562 was examined. RT-PCR on total RNA extracted from K562 cells detected the presence of hCTR mRNA. Further analysis demonstrated that multiple hCTR isoforms were present. Incubation of K562 cells with salmon calcitonin (sCT), but not amylin, caused an increase in intracellular levels of cAMP similar to that induced by forskolin treatment. We further demonstrated that butyrate induced erythroid differentiation of K562 cells caused a significant decrease in hCTR mRNA levels. However, phorbol myristate acetate (PMA) induced megakaryocytic differentiation of these cells had no significant effect on hCTR mRNA levels. We demonstrated that exposure to various concentrations of sCT had no effect on the cellular proliferation of K562 cells in vitro. CONCLUSION: Chronic myelogenous k562 cells express multiple CTR isoforms. However, CT does not effect K562 proliferation rates. It is likely that the small increase in intracellular levels of cAMP following CT treatment is not sufficient to interfere with cellular growth.

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