ABSTRACT
BACKGROUND: ATP-binding cassette transporters are important in the mechanism of multidrug resistance. ABCB1 displays a high affinity for imatinib. BMI1 is a polycomb group protein thought to be overexpressed in leukemic cells. METHODS: This study was conducted to investigate the prognostic value of ABCB1 and BMI1 expressions in chronic myeloid leukemia (CML). Expression levels were measured in 81 patients newly diagnosed with CML and 20 healthy controls by real time reverse transcription- PCR. RESULTS: The ABCB1 expression levels did not differ between patients with CML and controls. Low ABCB1 mRNA levels were observed in patients who achieved an optimal response compared to suboptimal and resistant cases (P=0.005). Non-responders showed the highest ABCB1 levels. ABCB1 expression did not affect the progression-free survival (PFS) of patients. BMI1 expression was higher in patients than that in controls (P=0.001). Patients in advanced phases expressed higher levels of BMI1 than those in the chronic phase (P=0.004). High BMI1 expression was associated with a shorter PFS. CONCLUSION: ABCB1 mRNA expression may serve as a predictor of the optimal response to imatinib treatment in patients with CML. BMI1 expression was higher in the accelerated and blastic crisis phases of CML and associated with a shorter PFS.
Subject(s)
Humans , ATP-Binding Cassette Transporters , Disease-Free Survival , Drug Resistance, Multiple , Imatinib Mesylate , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Polymerase Chain Reaction , Real-Time Polymerase Chain Reaction , RNA, MessengerABSTRACT
Hedgehog-Gli signaling pathway involves in vertebrate embryonic development ,tissue differ-entiation,organogenesis,and plays an important role in homeostasis ,the maintenance of stem cell function ,regula-tion of epithelial mesenchymal transition .Hedgehog-Gli signaling pathway activation correlates with a variety of tumor development ,invasion,apoptosis and drug resistance .This review seeks to clarify the composition of Hedge-hog-Gli signaling pathway ,mechanism of action ,the role of Hedgehog-Gli signaling pathway in lung cancer de-velopment and function of lung cell of the EGFR -TKI resistance .
ABSTRACT
The introduction of the BCR-ABL kinase inhibitor, imatinib mesylate (Gleevec®, Novartis) led to significant changes in the treatment of chronic myeloid leukaemia (CML) patients. However, despite the impressive percentage of responding patients, some CML cases, particularly those in advanced phases of the disease, show primary resistance or relapse after the initial response. The second-generation BCR-ABL inhibitors nilotinib (Tasigna®, Novartis) and dasatinib (Sprycel®, Bristol-Myers Squibb) have shown significant activity in clinical trials in patients who failed imatinib therapy, but these agents are still incapable of inhibiting the T315I mutant of Bcr-Abl and present partial activity in advanced phases of CML. The acquired biological notions of the mechanisms of tyrosine kinase inhibitor (TKI) resistance has led to the development of new compounds, some of which have shown encouraging preliminary results in clinical trials, even against T315I mutants. In this paper we discuss the new emerging therapies which may overcome TKI resistance in CML patients.
A introdução do inibidor de tirosino quinase BCR-ABL mesilato de imatinibe (Glivec®, Novartis) levou a significantes mudanças no tratamento da LMC. Entretanto, a despeito de impressionante porcentagem de pacientes que respondem, alguns casos de LMC, particularmente em fases avançadas da doença mostram resistência primaria ou recidivas após terapêutica inicial. Inibidores de tirosino quinases de segunda geração como o nilotinibe (Tasigna®, Novartis) e o dasatinibe (Sprycel®, Bristol Myers Squibb) têm mostrado significante atividade nos estudos clínicos em paciente onde o imatinibe falhou. Porém, estes agentes não são capazes de inibir a mutação T315I do Bcr-Abl e apresentam atividade parcial em fases avançadas da LMC. As noções biológicas adquiridas sobre os mecanismos de resistência aos inibidores de TK levaram ao desenvolvimento de novos compostos alguns dos quais têm resultados preliminares encorajadores incluindo a mutação T315I. Neste trabalho nós discutimos os novos agentes emergentes e qual o potencial poderão atingir para ultrapassar a resistência aos inibidores de TK em pacientes com LMC.