RESUMO
This study aimed to describe a short-term ex vivo assay to predict response to epidermal growth factor receptor (EGFR) targeted therapy (gefitinib) in adenocarcinoma patients. Four patients with locally advanced esophageal adenocarcinoma were treated with gefitinib (250 mg/day) for 14 days and pharmacokinetic (PK) studies were conducted to monitor plasma drug concentrations. Tumor cells were sampled by endoscopic biopsy prior to (baseline, day 0) and at the completion of (day 14) treatment. Cells obtained at baseline were exposed to gefitinib in short-term cell culture conditions (ex vivo assay). Western blot analyses with phospho-specific antibodies were performed to evaluate activation and biochemical response to therapy of EGFR and its downstream signaling components ERK and AKT ex vivo and in vivo. The in vivo profiles were correlated with the gefitinib-mediated alteration in proliferating cell nuclear antigen (PCNA) expression, a marker of cell proliferation. The correlation between EGFR expression and ERK activity was also investigated by immunohistochemical analysis in pretreatment biopsies. Mutational status of the genes encoding EGFR, K-RAS, and PI3KCA (the phosphoinositide 3-kinase catalytic subunit p110) as well as expression levels of PTEN protein were tested in order to investigate potential confounders of the gefitinib effect. All patients completed the gefitinib therapy. PK studies demonstrated constant gefitinib concentrations during the treatment, confirming persistent exposure of target tissue to the drug at sufficient levels to achieve EGFR blockade. Ex vivo culture with gefitinib resulted in distinct response patterns representing various states of activity of the ERK and AKT pathways. The results of the ex vivo studies correctly predicted the pharmacodynamic (PD) effects of the agents in tumor tissue in vivo. PCNA expression correlated with ERK pathway inhibition, but not with gefitinib-mediated inhibition of EGFR activity alone. Immunohistochemical analysis performed on pretreatment biopsies correlated with Western blot analysis of EGFR and phospho-ERK expression. No mutations were identified in exons 18-21 of EGFR, exons 2 and 3 of K-RAS or exons 9 and 22 of PI3KCA. Levels of PTEN were comparable across tumors. The novel pharmacodynamic approach described in this proof of principle study may be useful to refine the patient selection to maximize the potential benefits of drugs and design individualized rational therapies for cancer patients.
Assuntos
Química Farmacêutica/métodos , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Receptores ErbB/antagonistas & inibidores , Quinazolinas/farmacologia , Adenocarcinoma/tratamento farmacológico , Adulto , Antineoplásicos/farmacologia , Biópsia , Desenho de Fármacos , Endoscopia/métodos , Neoplasias Esofágicas/tratamento farmacológico , Éxons , Gefitinibe , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Cyclin D1 overexpression has been associated with poor prognosis and resistance to therapy in human breast cancer. Thus, the development of therapeutic agents that selectively target cyclin D1 activity is of clinical interest. This study demonstrates that 12-oxo-phytodienoic acid (OPDA), a phytohormone with critical functions in growth and development in plants, induces growth arrest in MDA-MB-231 and T47D breast cancer cells. In response to OPDA treatment, the human breast cancer cell lines exhibit a progressive decline in cyclin D1 expression, which is tightly associated with the accumulation of hypophosphorylated form of the retinoblastoma protein (Rb) and G1 arrest. The decrease in cyclin D1 protein expression accompanies a dramatic decline in nuclear but not membranous beta-catenin expression and activation of glycogen synthase kinase-3-beta (GSK3beta) caused by inhibition of its serine-9 phosphorylation. The proteasome inhibitor MG132 blocks OPDA-mediated decrease in cyclin D1. In addition, the overexpression of T286A, a cyclin D1 mutant which is refractory to phosphorylation by GSK3beta and proteosomal degradation, is resistant to OPDA-mediated Rb dephosphorylation as well as G(1) cell cycle arrest. Thus, our results demonstrate that degradation of cyclin D1 protein is a key event in OPDA induced growth inhibition in breast cancer cells. These data provide the basic foundation for future efforts to develop OPDA-based approaches in the prevention and treatment of breast cancer and other types of cancer.
Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Proliferação de Células/efeitos dos fármacos , Ciclina D1/efeitos dos fármacos , Ácidos Graxos Insaturados/farmacologia , Western Blotting , Linhagem Celular Tumoral , Ciclina D1/metabolismo , Feminino , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Proteína do Retinoblastoma/efeitos dos fármacos , Proteína do Retinoblastoma/metabolismo , beta Catenina/efeitos dos fármacos , beta Catenina/metabolismoRESUMO
At the present time, the optimal development of molecularly targeted anticancer agents is limited by the lack of clinically applicable tools to predict drug effects. This study aimed to develop methods that might be useful in predicting the efficacy of targeted agents in a novel model system of human pancreatic cancer. A series of xenografts were established in nude mice by implanting human pancreatic cancer tissue surgically resected from cancer patients. Animals were treated with the epidermal growth factor receptor inhibitor erlotinib, the mammalian target of rapamycin inhibitor temsirolimus, or vehicle. Tumor cells were sampled by fine-needle aspiration biopsy (FNAB) before (baseline, day 0) and at the completion of 28 days of treatment. Cells obtained at baseline were exposed to erlotinib or temsirolimus in short-term cell culture conditions (ex vivo). Western blot analysis was done to determine the degree of inhibition in the phosphorylation of extracellular signal-regulated kinase 1/2 and S6-ribosomal protein (downstream effectors of epidermal growth factor receptor and mammalian target of rapamycin, respectively) ex vivo and in vivo. Five of six xenografted tumors responded to temsirolimus, whereas only one tumor responded to erlotinib. The results of the ex vivo studies correctly predicted the pharmacodynamic effect of the agents in vivo as well as their gross antitumor effects. Finally, we showed the clinical feasibility of this approach, performing ex vivo assessment of drug-target response in FNAB samples from three patients with pancreatic cancer. Cancer cells obtained by FNAB, an established minimally invasive diagnostic procedure, can be used to test ex vivo the effects of targeted anticancer agents. These effects correlate with antitumor activity in vivo and may therefore provide an important tool applicable to clinical trials. Ultimately, an approach of this nature may facilitate the further refinement of patient selection in favor of individuals with molecular profiles, predicting a greater likelihood of therapeutic benefit.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Neoplasias Pancreáticas/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Quinazolinas/uso terapêutico , Sirolimo/análogos & derivados , Ensaios Antitumorais Modelo de Xenoenxerto , Adenocarcinoma/tratamento farmacológico , Animais , Biópsia por Agulha Fina , Receptores ErbB/antagonistas & inibidores , Cloridrato de Erlotinib , Humanos , Camundongos , Camundongos Nus , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Estudos Prospectivos , Sirolimo/uso terapêuticoRESUMO
One specific limitation to the clinical development of targeted cancer therapeutics is the lack of well-validated pharmacodynamic markers. Such tools might conceivably provide a framework within which to better evaluate the selection of specific molecules as therapeutic targets. Nevertheless, the practical application of this hypothesis in clinical development remains elusive. In this study, we present a minimally invasive pharmacodynamic assay for monitoring therapy-mediated changes in the activity of target signaling pathways by using fine needle aspiration (FNA) samples and quantitative ELISA methods. To this end, we used the HuCCT-1 cholangiocarcinoma cell line treated with gefitinib (ZD1839, Iressa), a selective blocker of the epidermal growth factor receptor (EGFR), and CI-1040, a selective inhibitor of the mitogen extracellular regulated kinase [mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase 1/2]. HuCCT-1 cells were resistant to gefitinib and CI-1040 alone but susceptible to the combination of these drugs in vitro and in vivo. This effect was associated with a greater inhibition of ERK1/2 activation, a downstream mediator in the EGFR-mitogen-activated protein/ERK kinase pathway. Using this model, we sought to assess whether FNA-obtained tumor biopsies could be used to measure signaling pathway activation. Cellular extracts prepared from FNA samples yielded adequately cellular, high-quality samples to assess therapy-mediated changes in EGFR and ERK1/2 phosphorylation by Western blotting and quantitative ELISA assays. Treatment with gefitinib alone effectively inhibited EGFR activation but failed to block ERK1/2 phosphorylation and tumor growth. Blocking was achieved by the addition of CI-1040 to the treatment regimen. These results show that the combination of serial FNA sampling with highly sensitive quantitative ELISA assays permits assessment of therapy-mediated changes in signaling pathways, which correlate well with antitumor effects. This assay is simple to implement and broadly applicable to diverse tumor types in clinical studies with cancer patients and may be useful in the development of targeted anticancer agents.