Project description:The molecular etiology underlying TRPS1 loss-of-function in tricho-rhino-phalangeal syndrome (TRPS) remains to be understood. Intriguingly, TRPS1 is also bioinformatically postulated as a breast cancer driver. We report here that TRPS1 is prevalently amplified in breast cancer and promotes breast carcinogenesis. We showed that the tumorigenic potential of TRPS1 is derived from its nucleation of the replication machinery and its enforced replication of H3K9me3-marked heterochromatic regions. During early stage of genome duplication, TRPS1 encourages chromatin loading of the anaphase-promoting complex (APC/C) and subsequent degradation of Geminin, an inhibitor for the assembly of the pre-replication complex, leading to uncontrolled refiring of the heterochromatic replication origins. Overexpression of wild-type but not TRPS-associated loss-of-function mutants of TRPS1 is sufficient to drive genome amplification that mimics the genomic alterations in cancer, and TRPS1-evoked aberrant genome dynamically evolves to confer therapeutic resistance to a broad spectrum of treatment compounds. Together, these results link TRPS1 to heterochromatin replication, highlighting the sufficiency of a single oncogene to drive cancer genome evolution.
Project description:The molecular etiology underlying TRPS1 loss-of-function in tricho-rhino-phalangeal syndrome (TRPS) remains to be understood. Intriguingly, TRPS1 is also bioinformatically postulated as a breast cancer driver. We report here that TRPS1 is prevalently amplified in breast cancer and promotes breast carcinogenesis. We showed that the tumorigenic potential of TRPS1 is derived from its nucleation of the replication machinery and its enforced replication of H3K9me3-marked heterochromatic regions. During early stage of genome duplication, TRPS1 encourages chromatin loading of the anaphase-promoting complex (APC/C) and subsequent degradation of Geminin, an inhibitor for the assembly of the pre-replication complex, leading to uncontrolled refiring of the heterochromatic replication origins. Overexpression of wild-type but not TRPS-associated loss-of-function mutants of TRPS1 is sufficient to drive genome amplification that mimics the genomic alterations in cancer, and TRPS1-evoked aberrant genome dynamically evolves to confer therapeutic resistance to a broad spectrum of treatment compounds. Together, these results link TRPS1 to heterochromatin replication, highlighting the sufficiency of a single oncogene to drive cancer genome evolution.
Project description:Mutations in TRPS1 cause trichorhinophalangeal syndrome types I and III, which are characterized by sparse scalp hair in addition to craniofacial and skeletal abnormalities. Trps1 is a vertebrate transcription factor containing nine zinc-finger domains, including a GATA-type zinc finger through which it binds DNA. Mice in which the GATA domain of Trps1 has been deleted (Trps1∆gt/∆gt) have a reduced number of pelage follicles and lack vibrissae follicles postnatally. To identify the transcriptional targets of Trps1 in the developing vibrissa follicle, we performed microarray hybridization analysis comparing expression patterns in the whisker pads of wild-type versus Trps1∆gt/∆gt embryos. We identified a number of transcription factors and Wnt inhibitors among transcripts downregulated in the mutant embryos, and several extracellular matrix proteins there were upregulated in the mutant samples. Whole whisker pads were dissected from E12.5 embryos and total RNA was isolated using the RNeasy Mini Kit (Qiagen). Triplicate RNA samples from three independent embryos of each genotype were amplified and labeled for hybridization to Affymetrix GeneChip MOE430A microarrays using Affymetrix reagents and protocols. The data output was analyzed using GeneSpring GX 10.0 commercial software (Agilent Technologies). P-values were calculated using an unpaired t-test. Expression values with a p-value less than or equal to 0.05 and a fold difference of at least 1.5 relative to wild-type baseline expression levels were considered significant.
Project description:TRPS1 was recently identified as a radiation marker in breast cancer. In order to characterise the molecular phenotype that is associated with TRPS1 we knocked out the gene in two radiation-transformed breast cell lines.
Project description:The GATA transcription factor TRPS1 is a context-dependent oncogene in breast cancer. In the mammary gland, TRPS1 activity is restricted to the luminal population and sustains the initial branching of the mammary ducts at puberty as well as the lactogenic differentiation during pregnancy. Its function in the resting mammary gland however, remains unclear. To evaluate whether it could be a target for cancer therapy, we investigated TRPS1 function in the healthy resting mammary gland using a conditional ubiquitous depletion mouse model where long-term depletion does not affect fitness. we show that TRPS1 activity is critical to maintain a functional luminal progenitor compartment and that this involves the repression of the SRF/MRTF and the YAP/TAZ transcriptional program. Mechanistically, this repression involves Krt8-dependent RhoA modulation. Our work uncovers a hitherto undisclosed function of TRPS1 in luminal progenitors which is intrinsically linked to mechanotransduction in the mammary gland. It also provides new insights into the oncogenic functions of TRPS1 since luminal progenitors are likely the cells of origin of many breast cancers.
Project description:The GATA transcription factor TRPS1 is a context-dependent oncogene in breast cancer. In the mammary gland, TRPS1 activity is restricted to the luminal population and sustains the initial branching of the mammary ducts at puberty as well as the lactogenic differentiation during pregnancy. Its function in the resting mammary gland however, remains unclear. To evaluate whether it could be a target for cancer therapy, we investigated TRPS1 function in the healthy resting mammary gland using a conditional ubiquitous depletion mouse model where long-term depletion does not affect fitness. we show that TRPS1 activity is critical to maintain a functional luminal progenitor compartment and that this involves the repression of the SRF/MRTF and the YAP/TAZ transcriptional program. Mechanistically, this repression involves Krt8-dependent RhoA modulation. Our work uncovers a hitherto undisclosed function of TRPS1 in luminal progenitors which is intrinsically linked to mechanotransduction in the mammary gland. It also provides new insights into the oncogenic functions of TRPS1 since luminal progenitors are likely the cells of origin of many breast cancers.
Project description:The GATA transcription factor TRPS1 is a context-dependent oncogene in breast cancer. In the mammary gland, TRPS1 activity is restricted to the luminal population and sustains the initial branching of the mammary ducts at puberty as well as the lactogenic differentiation during pregnancy. Its function in the resting mammary gland however, remains unclear. To evaluate whether it could be a target for cancer therapy, we investigated TRPS1 function in the healthy resting mammary gland using a conditional ubiquitous depletion mouse model where long-term depletion does not affect fitness. we show that TRPS1 activity is critical to maintain a functional luminal progenitor compartment and that this involves the repression of the SRF/MRTF and the YAP/TAZ transcriptional program. Mechanistically, this repression involves Krt8-dependent RhoA modulation. Our work uncovers a hitherto undisclosed function of TRPS1 in luminal progenitors which is intrinsically linked to mechanotransduction in the mammary gland. It also provides new insights into the oncogenic functions of TRPS1 since luminal progenitors are likely the cells of origin of many breast cancers.
Project description:The GATA transcription factor TRPS1 is a context-dependent oncogene in breast cancer. In the mammary gland, TRPS1 activity is restricted to the luminal population and sustains the initial branching of the mammary ducts at puberty as well as the lactogenic differentiation during pregnancy. Its function in the resting mammary gland however, remains unclear. To evaluate whether it could be a target for cancer therapy, we investigated TRPS1 function in the healthy resting mammary gland using a conditional ubiquitous depletion mouse model where long-term depletion does not affect fitness. we show that TRPS1 activity is critical to maintain a functional luminal progenitor compartment and that this involves the repression of the SRF/MRTF and the YAP/TAZ transcriptional program. Mechanistically, this repression involves Krt8-dependent RhoA modulation. Our work uncovers a hitherto undisclosed function of TRPS1 in luminal progenitors which is intrinsically linked to mechanotransduction in the mammary gland. It also provides new insights into the oncogenic functions of TRPS1 since luminal progenitors are likely the cells of origin of many breast cancers.