Drug resistance remains a major obstacle to successful cancer treatment. Here we use a novel approach to identify rapamycin as a glucocorticoid resistance reversal agent. A database of drug-associated gene expression profiles was screened for molecules whose profile overlapped with a gene expression signature of glucocorticoid (GC) sensitivity/resistance in Acute Lymphoblastic Leukemia (ALL) cells. The screen indicated the mTOR inhibitor rapamycin profile matched the signature of GC-sensitivity. We thus tested the hypothesis that rapamycin would induce GC sensitivity in lymphoid malignancy cells, and found that it sensitized cells to glucocorticoid induced apoptosis via modulation of antiapoptotic MCL1. These data indicate that MCL1 is an important regulator of GC-induced apoptosis, and that the combination of rapamycin and glucocorticoids has potential utility in ALL. Furthermore this approach represents a novel strategy for identification of promising combination therapies for cancer.
Gene expression-based chemical genomics identifies rapamycin as a modulator of MCL1 and glucocorticoid resistance.
No sample metadata fields
View SamplesTumor associated macrophages show signs of both, classical pro-inflammatory as well as alternative macrophage activation. The aim of this study was to compare TAMs across tumor types, to characterize their phenotype in detail and to identify the signaling nodules involved regulating classical and alternative activation traits.
Myeloid-derived suppressor activity is mediated by monocytic lineages maintained by continuous inhibition of extrinsic and intrinsic death pathways.
Specimen part
View SamplesDrug resistance remains a major obstacle to successful cancer treatment. Here we use a novel approach to identify rapamycin as a glucocorticoid resistance reversal agent. A database of drug-associated gene expression profiles was screened for molecules whose profile overlapped with a gene expression signature of glucocorticoid (GC) sensitivity/resistance in Acute Lymphoblastic Leukemia (ALL) cells. The screen indicated the mTOR inhibitor rapamycin profile matched the signature of GC-sensitivity. We thus tested the hypothesis that rapamycin would induce GC sensitivity in lymphoid malignancy cells, and found that it sensitized cells to glucocorticoid induced apoptosis via modulation of antiapoptotic MCL1. These data indicate that MCL1 is an important regulator of GC-induced apoptosis, and that the combination of rapamycin and glucocorticoids has potential utility in ALL. Furthermore this approach represents a novel strategy for identification of promising combination therapies for cancer.
Gene expression-based chemical genomics identifies rapamycin as a modulator of MCL1 and glucocorticoid resistance.
No sample metadata fields
View SamplesDrug resistance remains a major obstacle to successful cancer treatment. Here we use a novel approach to identify rapamycin as a glucocorticoid resistance reversal agent. A database of drug-associated gene expression profiles was screened for molecules whose profile overlapped with a gene expression signature of glucocorticoid (GC) sensitivity/resistance in Acute Lymphoblastic Leukemia (ALL) cells. The screen indicated the mTOR inhibitor rapamycin profile matched the signature of GC-sensitivity. We thus tested the hypothesis that rapamycin would induce GC sensitivity in lymphoid malignancy cells, and found that it sensitized cells to glucocorticoid induced apoptosis via modulation of antiapoptotic MCL1. These data indicate that MCL1 is an important regulator of GC-induced apoptosis, and that the combination of rapamycin and glucocorticoids has potential utility in ALL. Furthermore this approach represents a novel strategy for identification of promising combination therapies for cancer.
Gene expression-based chemical genomics identifies rapamycin as a modulator of MCL1 and glucocorticoid resistance.
No sample metadata fields
View SamplesDrug resistance remains a major obstacle to successful cancer treatment. Here we use a novel approach to identify rapamycin as a glucocorticoid resistance reversal agent. A database of drug-associated gene expression profiles was screened for molecules whose profile overlapped with a gene expression signature of glucocorticoid (GC) sensitivity/resistance in Acute Lymphoblastic Leukemia (ALL) cells. The screen indicated the mTOR inhibitor rapamycin profile matched the signature of GC-sensitivity. We thus tested the hypothesis that rapamycin would induce GC sensitivity in lymphoid malignancy cells, and found that it sensitized cells to glucocorticoid induced apoptosis via modulation of antiapoptotic MCL1. These data indicate that MCL1 is an important regulator of GC-induced apoptosis, and that the combination of rapamycin and glucocorticoids has potential utility in ALL. Furthermore this approach represents a novel strategy for identification of promising combination therapies for cancer.
Gene expression-based chemical genomics identifies rapamycin as a modulator of MCL1 and glucocorticoid resistance.
No sample metadata fields
View SamplesSomatic mitochondrial DNA (mtDNA) mutations contribute to the pathogenesis of age-related disorders, including myelodysplastic syndromes (MDS). The accumulation of mitochondria harboring mtDNA mutations in patients with these disorders suggests a failure of normal mitochondrial quality-control systems. The mtDNA-mutator mice acquire somatic mtDNA mutations via a targeted defect in the proofreading function of the mtDNA polymerase, PolgA, and develop macrocytic anemia similar to that of patients with MDS. We observed an unexpected defect in clearance of dysfunctional mitochondria at specific stages during erythroid maturation in hematopoietic cells from aged mtDNA-mutator mice. Mechanistically, aberrant activation of mechanistic target of rapamycin signaling and phosphorylation of uncoordinated 51-like kinase (ULK) 1 in mtDNA-mutator mice resulted in proteasome mediated degradation of ULK1 and inhibition of autophagy in erythroid cells. To directly evaluate the consequence of inhibiting autophagy on mitochondrial function in erythroid cells harboring mtDNA mutations in vivo, we deleted Atg7 from erythroid progenitors of wildtype and mtDNA-mutator mice. Genetic disruption of autophagy did not cause anemia in wild-type mice but accelerated the decline in mitochondrial respiration and development of macrocytic anemia in mtDNA-mutator mice. These findings highlight a pathological feedback loop that explains how dysfunctional mitochondria can escape autophagy-mediated degradation and propagate in cells predisposed to somatic mtDNA mutations, leading to disease.
Mito-protective autophagy is impaired in erythroid cells of aged mtDNA-mutator mice.
Specimen part
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