Project description:Cdk4 and Cdk6 are two related kinases that bind D-type cyclins and regulate cell cycle progression. Due to their relevance in cancer, Cdk4/6 inhibitors are currently in advanced clinical trials in multiple tumor types. Cdk4/6 are inhibited by INK4 proteins that exert tumor suppressing functions. To test the significance of this inhibitory mechanism we have generated knock-in mice that express a Cdk6 mutant (Cdk6 R31C) insensitive to INK4-mediated inhibition. Cdk6R/R mice display altered development of the hematopoietic system without resulting in enhanced tumor susceptibility, either in the presence or absence of p53. The presence of the Cdk6 R31C allele results in defective potential of hematopoietic progenitors in adoptive transfer assays or after induced damage. These defects are rescued after complete insensitivity to INK4 inhibitors in Cdk4R/R; Cdk6R/R double mutant mice, and INK4-resistant mice display increased susceptibility to hematopoietic and endocrine tumors. In BCR-ABL-transformed hematopoietic cells, the presence of the Cdk6 R31C allele results in increased binding of p16INK4a to wild-type Cdk4, whereas the double mutant is fully insensitive to INK4 inhibitors resulting in accelerated disease onset. Our observations reveal that Cdk4 and Cdk6 cooperate in tumor development and suggest a role for Cdk6 in buffering INK4 protein levels thus contributing to the development of hematopoietic tumors. The presence of the Cdk4 R24C and Cdk6 R31C alleles results in relevant changes in the expression profiles of cancer cells including deregulation of apoptosis and other processes. p185BCR-ABL1 was used to transform wild-type or double knock-in Cdk4 R24C; Cdk6 R31C fetal livers. Cell lines were isolated as spontaneous immortal and transformed clones after transduction of fetal liver with a p185 BCR-ABL1-transgene. RNA was isolated from asynchronous cultures. Two-condition experiment, Cdk4R-Cdk6R cells versus wild-type cells. Biological replicates: 3 control replicates, 3 transfected replicates.
Project description:To elucidate the mechanism of BCL6-mediated pre-B cell survival signaling, we investigated the gene expression pattern in BCR-ABL1-transformed BCL6+/+ and BCL6-/- B cell precursors. Pharmacological inhibition of BCR-ABL1 was performed with the BCR-ABL1 kinase inhibitor STI571 (Imatinib).
Project description:Cdk4 and Cdk6 are two related kinases that bind D-type cyclins and regulate cell cycle progression. Due to their relevance in cancer, Cdk4/6 inhibitors are currently in advanced clinical trials in multiple tumor types. Cdk4/6 are inhibited by INK4 proteins that exert tumor suppressing functions. To test the significance of this inhibitory mechanism we have generated knock-in mice that express a Cdk6 mutant (Cdk6 R31C) insensitive to INK4-mediated inhibition. Cdk6R/R mice display altered development of the hematopoietic system without resulting in enhanced tumor susceptibility, either in the presence or absence of p53. The presence of the Cdk6 R31C allele results in defective potential of hematopoietic progenitors in adoptive transfer assays or after induced damage. These defects are rescued after complete insensitivity to INK4 inhibitors in Cdk4R/R; Cdk6R/R double mutant mice, and INK4-resistant mice display increased susceptibility to hematopoietic and endocrine tumors. In BCR-ABL-transformed hematopoietic cells, the presence of the Cdk6 R31C allele results in increased binding of p16INK4a to wild-type Cdk4, whereas the double mutant is fully insensitive to INK4 inhibitors resulting in accelerated disease onset. Our observations reveal that Cdk4 and Cdk6 cooperate in tumor development and suggest a role for Cdk6 in buffering INK4 protein levels thus contributing to the development of hematopoietic tumors. The presence of the Cdk4 R24C and Cdk6 R31C alleles results in relevant changes in the expression profiles of cancer cells including deregulation of apoptosis and other processes.
Project description:To elucidate the mechanism of BCL6-mediated pre-B cell survival signaling, we investigated the gene expression pattern in BCR-ABL1-transformed BCL6+/+ and BCL6-/- B cell precursors. Pharmacological inhibition of BCR-ABL1 was performed with the BCR-ABL1 kinase inhibitor STI571 (Imatinib). BCR-ABL1 transformed B cell precursors of BCL6 wildtype and BCL6 knockout mice were either treated with 10µM STI571 (Imatinib) for 16 hours or cultured in absence of STI571. Three samples for each condition were processed.
Project description:In order to investigate the function of MYC in ALL, we isolated bone marrow cells from conditional MYC knockout mice and transformed them with BCR-ABL1. In a second transduction the BCR-ABL1 driven pre-B cells were transformed either with CRE or empty vector control.
Project description:In order to investigate the function of IKZF1 in ALL, we isolated bone marrow cells from C57Bl6 mice and transformed them with BCR-ABL1. In a second transduction the BCR-ABL1 driven pre-B cells were transformed either with IKZF1-GFP or empty vector control (GFP) and subjected to gene expression analysis.
Project description:In order to investigate the function of PAX5 in ALL, we isolated bone marrow cells from C57Bl6 mice and transformed them with BCR-ABL1. In a second transduction the BCR-ABL1 driven pre-B cells were transformed either with PAX5-GFP or empty vector control (GFP) and subjected to gene expression analysis.
Project description:This comparative genomic hybridization (CGH) study investigated the effect of BCL6 on clonal evolution in BCR-ABL1-driven acute lymphoblastic leukemia (ALL). The frequencies of copy number alterations in BCR-ABL1-transformed BCL6+/+ and BCL6-/- leukemias were determined. Three BCR-ABL1-transformed BCL6+/+ and BCL6-/- ALL samples derived from mice were maintained for 4 month in cell culture and were subjected to CGH analysis. As control samples, normal untransformed splenoytes were used.