RESUMO
Positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) is frequently used for visualizing gastrointestinal stromal tumors (GIST), which are highly glucose-avid tumors. Dramatic metabolic responses following imatinib treatment indicate a high, KIT-dependent glucose turnover which has been particularly helpful for predicting tumor response to imatinib. The glucose analogue 2-deoxyglucose (2DG) inhibits glucose metabolism in cancer cells that depend on aerobic glycolysis for ATP production. We show that 2DG inhibits proliferation in both imatinib-sensitive and imatinib-resistant GIST cell lines at levels that can be achieved clinically. KIT-negative GIST48B have 3-14-fold higher IC50 levels than KIT-positive GIST cells indicating that oncogenic KIT may sensitize cells to 2DG. GIST sensitivity to 2DG is increased in low-glucose media (110 mg/dl). 2DG leads to dose- and glucose dependent inhibition of KIT glycosylation with resultant reduction of membrane-bound KIT, inhibition of KIT-phosphorylation and inactivation of KIT-dependent signaling intermediates. In contrast to imatinib, 2DG caused ER-stress and elicited the unfolded protein response (UPR). Mannose but not pyruvate rescued GIST cells from 2DG-induced growth arrest, suggesting that loss of KIT integrity is the predominant effect of 2DG in GIST. Additive anti-tumoral effects were seen with imatinib and BH3-mimetics. Our data provide the first evidence that modulation of the glucose-metabolism by 2DG may have a disease-specific effect and may be therapeutically useful in GIST.
Assuntos
Compostos de Anilina/farmacologia , Apoptose/efeitos dos fármacos , Desoxiglucose/farmacologia , Tumores do Estroma Gastrointestinal/metabolismo , Proteínas Proto-Oncogênicas c-kit/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas/farmacologia , Compostos de Anilina/agonistas , Animais , Apoptose/genética , Linhagem Celular Tumoral , Desoxiglucose/agonistas , Sinergismo Farmacológico , Tumores do Estroma Gastrointestinal/genética , Tumores do Estroma Gastrointestinal/patologia , Glicosilação/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Proteínas Proto-Oncogênicas c-kit/genética , Transdução de Sinais/genética , Sulfonamidas/agonistasRESUMO
Interactions between the dual BCR/ABL and Src inhibitor bosutinib and the Chk1 inhibitor PF-00477736 were examined in BCR/ABL(+) leukemia cells, particularly imatinib-resistant cells, including those with the T315I mutation. Bosutinib blocked PF-00477736-induced ERK1/2 activation and sharply increased apoptosis in association with Mcl-1 inhibition, p34(cdc2) dephosphorylation, BimEL up-regulation, and DNA damage in imatinib-resistant CML or Ph(+) ALL cell lines. Inhibition of Src or MEK1 by shRNA significantly enhanced PF-0047736 lethality. Bosutinib/PF-00477736 co-treatment also potentiated cell death in CD34(+) CML patient samples, including dasatinib-resistant blast crisis cells exhibiting both T315I and E355G mutations, but was minimally toxic to normal CD34(+) cells. Finally, combined in vivo treatment significantly suppressed BaF3/T315I tumor growth and prolonged survival in an allogeneic mouse model. Together, these findings suggest that this targeted combination strategy warrants attention in IM-resistant CML or Ph(+) ALL.
Assuntos
Compostos de Anilina , Antineoplásicos/farmacologia , Benzamidas , Benzodiazepinonas , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proteínas de Fusão bcr-abl/metabolismo , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Nitrilas , Piperazinas , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Inibidores de Proteínas Quinases , Proteínas Quinases/metabolismo , Pirazóis , Pirimidinas , Quinolinas , Substituição de Aminoácidos , Compostos de Anilina/agonistas , Compostos de Anilina/farmacologia , Animais , Benzodiazepinonas/agonistas , Benzodiazepinonas/farmacologia , Quinase 1 do Ponto de Checagem , Resistencia a Medicamentos Antineoplásicos/genética , Sinergismo Farmacológico , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Proteínas de Fusão bcr-abl/genética , Humanos , Mesilato de Imatinib , Células K562 , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/metabolismo , Leucemia Linfocítica Crônica de Células B/patologia , MAP Quinase Quinase 1/genética , MAP Quinase Quinase 1/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Nus , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Mutação de Sentido Incorreto , Proteína de Sequência 1 de Leucemia de Células Mieloides , Nitrilas/agonistas , Nitrilas/farmacologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Pirazóis/agonistas , Pirazóis/farmacologia , Quinolinas/agonistas , Quinolinas/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Acute myeloid leukemia (AML) cells are relatively resistant to tumor necrosis factor alpha-related apoptosis-inducing ligand (TRAIL). We previously reported that triptolide, a potent anticancer agent from a Chinese herb, decreases XIAP in leukemic cells. We evaluated the combination of triptolide and TRAIL and found synergistic promotion of apoptosis in AML cells. XIAP-overexpressing U937 cells (U937XIAP) were more resistant to TRAIL than U937neo cells, and inhibition of XIAP with the small-molecule inhibitor 1396-11 enhanced TRAIL-induced apoptosis, implying XIAP as a resistance factor in AML. Furthermore, triptolide increased DR5 levels in OCI-AML3, while the DR5 increase was blunted in p53-knockdown OCI-AML3 and p53-mutated U937 cells, confirming a role for p53 in the regulation of DR5. In support of this finding, disruption of MDM2-p53 binding with subsequent increase in p53 levels by nutlin3a increased DR5 levels and sensitized OCI-AML3 cells to TRAIL. The combination of 1396-11 plus nutlin3a plus TRAIL was more effective than either the 1396-11 and TRAIL or nutlin3a and TRAIL combinations in OCI-AML3 cells, further supporting the role of triptolide as a sensitizer to TRAIL-induced apoptosis in part by independent modulation of XIAP expression and p53 signaling. Thus, the combination of triptolide and TRAIL may provide a novel strategy for treating AML by overcoming critical mechanisms of apoptosis resistance.
