Androgen receptor functions as transcriptional repressor of Cancer Associated Fibroblast (CAF) activation [RNA-seq]
Ontology highlight
ABSTRACT: The age-associated increase of cancer risk has been linked with stromal fibroblast senescence and early steps of Cancer Associated Fibroblast (CAF) activation. Surprisingly little is known about the role of androgen receptor (AR) signalling in this context. We show that AR expression is down-modulated in stromal fibroblasts underlying premalignant skin cancer lesions (actinic keratoses, AK) as well as in CAFs from the three major skin cancer types, squamous (SCC) and basal cell (BCC) carcinomas and melanomas. Decreased AR expression is linked to the concomitant down-modulation of CSL, key effector of canonical Notch signalling and global modulator of chromatin configuration, and it can be counteracted by treatment with BET inhibitors, which reverse CAF activation. Functionally, AR gene silencing in dermal fibroblasts results in p53-dependent senescence and induction of key CAF-effector genes, with AR physically converging with CSL in negative control of these genes. The findings are of functional significance as, in an orthotopic model of skin cancer, dermal fibroblasts with AR loss enhance significantly tumorigenicity of SCC and melanoma cells. As such, the findings establish AR as a novel potential target for stroma-focused cancer prevention and treatment.
Project description:The age-associated increase of cancer risk has been linked with stromal fibroblast senescence and early steps of Cancer Associated Fibroblast (CAF) activation. Surprisingly little is known about the role of androgen receptor (AR) signalling in this context. We show that AR expression is down-modulated in stromal fibroblasts underlying premalignant skin cancer lesions (actinic keratoses, AK) as well as in CAFs from the three major skin cancer types, squamous (SCC) and basal cell (BCC) carcinomas and melanomas. Decreased AR expression is linked to the concomitant down-modulation of CSL, key effector of canonical Notch signalling and global modulator of chromatin configuration, and it can be counteracted by treatment with BET inhibitors, which reverse CAF activation. Functionally, AR gene silencing in dermal fibroblasts results in p53-dependent senescence and induction of key CAF-effector genes, with AR physically converging with CSL in negative control of these genes. The findings are of functional significance as, in an orthotopic model of skin cancer, dermal fibroblasts with AR loss enhance significantly tumorigenicity of SCC and melanoma cells. As such, the findings establish AR as a novel potential target for stroma-focused cancer prevention and treatment.
Project description:Senescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-J? in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, and p53 activation provides a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblast senescence, enhances expression of CAF effector genes and, in vivo, promotes tumour and stromal cell expansion. Together, the findings support a CAF activation/stromal evolution model under convergent CSL/p53 control. Examination of genome-wide CSL binding sites in primary human dermal fibroblasts usinf two different antibodies against CSL
Project description:Senescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-Jκ in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, and p53 activation provides a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblast senescence, enhances expression of CAF effector genes and, in vivo, promotes tumour and stromal cell expansion. Together, the findings support a CAF activation/stromal evolution model under convergent CSL/p53 control. Human Dermal Fibroblasts were transfected with two different siRNA against CSL in parallel with a control siRNA. Total RNA was extracted 3 days post-transfection, followed by RNA-Seq analysis.
Project description:Senescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-Jκ in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, and p53 activation provides a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblast senescence, enhances expression of CAF effector genes and, in vivo, promotes tumour and stromal cell expansion. Together, the findings support a CAF activation/stromal evolution model under convergent CSL/p53 control.
Project description:Senescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-Jκ in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, and p53 activation provides a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblast senescence, enhances expression of CAF effector genes and, in vivo, promotes tumour and stromal cell expansion. Together, the findings support a CAF activation/stromal evolution model under convergent CSL/p53 control.
Project description:Senescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-J-kappa in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, with p53 activation providing a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblasts senescence, enhances CAF effector gene expression and, in vivo, promotes stromal and cancer cell expansion. Together, these findings support a CAF activation/stromal evolution model under convergent CSL/p53 control. We used microarrays to detail the global changes in gene expression in human dermal fibroblasts after CSL silencing
Project description:Genomic instability is a hallmark of cancer. Whether or not it also occurs in cancer-associated fibroblasts (CAFs) is a question of importance for the cancer/stromal cell co-evolution process. We find that DNA damage, telomere shortening and chromosome fusions occur at early times of CAF activation, as triggered by silencing of the CSL/RBP-J-κ gene in primary human dermal fibroblasts (HDFs) from multiple individuals. Similar alterations occur in skin Squamous Cell Carcinoma (SCC) - derived CAFs, in which CSL is down-modulated, versus HDFs from unaffected skin of the same patients. Mechanistically, CSL is part of a telomere protective complex with UPF1, KU70, and KU80 proteins, which fail to bind to telomeres in the absence of CSL. In CAFs, persistent genomic instability is associated with frequent amplification and overexpression of NOTCH1 gene, which is required to suppress DNA damage-induced ATM/P53 activation and growth arrest. These findings are of translational significance as, in an orthotopic model of skin SCC, genetic or pharmacological suppression of NOTCH1 activity suppresses cancer/stromal cell proliferation and expansion.
Project description:Stromal cell senescence plays a crucial role in activating cancer-associated fibroblasts (CAFs). The Androgen receptor (AR) function oversees cellular senescence and CAF activation. Here, we identify the mesenchymal-specific transcriptional coregulator ANKRD1 as a key driver of CAF conversion. ANKRD1 is strongly upregulated in CAFs and under direct negative control of AR, and its loss impairs the pro-tumorigenic potential of CAFs. ANKRD1 controls a CAF-specific gene expression program and is associated with poorer survival of HNSCC, lung, and cervical SCC patients. Mechanistically, ANKRD1 binds to the chromatin on CAF gene regulatory regions in a complex with the AP1 transcription factor family. We show that ANKRD1 enhances the AP1 DNA binding activity to CAF gene promoters. Targeting ANKRD1 with the FANA antisense oligonucleotides reverts CAFs into a normal fibroblast, disrupts AP1 complex formation, and blocks CAF’s pro-tumorigenic potential in an orthotopic model of SCC, thus representing an exciting target for stroma-oriented cancer therapy.
Project description:Stromal cell senescence plays a crucial role in activating cancer-associated fibroblasts (CAFs). The Androgen receptor (AR) function oversees cellular senescence and CAF activation. Here, we identify the mesenchymal-specific transcriptional coregulator ANKRD1 as a key driver of CAF conversion. ANKRD1 is strongly upregulated in CAFs and under direct negative control of AR, and its loss impairs the pro-tumorigenic potential of CAFs. ANKRD1 controls a CAF-specific gene expression program and is associated with poorer survival of HNSCC, lung, and cervical SCC patients. Mechanistically, ANKRD1 binds to the chromatin on CAF gene regulatory regions in a complex with the AP1 transcription factor family. We show that ANKRD1 enhances the AP1 DNA binding activity to CAF gene promoters. Targeting ANKRD1 with the FANA antisense oligonucleotides reverts CAFs into a normal fibroblast, disrupts AP1 complex formation, and blocks CAF’s pro-tumorigenic potential in an orthotopic model of SCC, thus representing an exciting target for stroma-oriented cancer therapy.
Project description:Stromal cell senescence plays a crucial role in activating cancer-associated fibroblasts (CAFs). The Androgen receptor (AR) function oversees cellular senescence and CAF activation. Here, we identify the mesenchymal-specific transcriptional coregulator ANKRD1 as a key driver of CAF conversion. ANKRD1 is strongly upregulated in CAFs and under direct negative control of AR, and its loss impairs the pro-tumorigenic potential of CAFs. ANKRD1 controls a CAF-specific gene expression program and is associated with poorer survival of HNSCC, lung, and cervical SCC patients. Mechanistically, ANKRD1 binds to the chromatin on CAF gene regulatory regions in a complex with the AP1 transcription factor family. We show that ANKRD1 enhances the AP1 DNA binding activity to CAF gene promoters. Targeting ANKRD1 with the FANA antisense oligonucleotides reverts CAFs into a normal fibroblast, disrupts AP1 complex formation, and blocks CAF’s pro-tumorigenic potential in an orthotopic model of SCC, thus representing an exciting target for stroma-oriented cancer therapy.