ABSTRACT: Transcriptional regulation of gene expression plays a fundamental role in coordinating molecular and metabolic responses to stress conditions. The stress-responsive Transcription Factor EB (TFEB), the master controller of lysosomal biogenesis and autophagy, is regulated at the post-translational level by the nutrient-sensitive kinase complex TORC1. However, little is known about the transcriptional regulation of TFEB in physiological and pathological conditions. Here, we show that during starvation, the immediate-early gene EGR1 binds to the TFEB promoter and positively regulates TFEB expression. EGR1 depletion dampened TFEB-mediated transcriptional response to starvation and significantly inhibited cell proliferation in cellular and 3D spheroid models of Birt-Hogg-Dube' (BHD) syndrome, a TFEB-driven inherited cancer condition. Consistently, the MEK1/2 inhibitor Trametinib, known to inhibit EGR1 expression, suppressed the proliferation of BHD patient-derived cancer cells, suggesting that pharmacological inhibition of the EGR1-TFEB axis may represent a therapeutic strategy to counteract constitutive TFEB activation in cancer-associated conditions.
Project description:Transcriptional regulation of gene expression plays a fundamental role in coordinating molecular and metabolic responses to stress conditions. The stress-responsive Transcription Factor EB (TFEB), the master controller of lysosomal biogenesis and autophagy, is regulated at the post-translational level by the nutrient-sensitive kinase complex TORC1. However, little is known about the transcriptional regulation of TFEB in physiological and pathological conditions. Here, we show that during starvation, the immediate-early gene EGR1 binds to the TFEB promoter and positively regulates TFEB expression. EGR1 depletion dampened TFEB-mediated transcriptional response to starvation and significantly inhibited cell proliferation in cellular and 3D spheroid models of Birt-Hogg-Dube' (BHD) syndrome, a TFEB-driven inherited cancer condition. Consistently, the MEK1/2 inhibitor Trametinib, known to inhibit EGR1 expression, suppressed the proliferation of BHD patient-derived cancer cells, suggesting that pharmacological inhibition of the EGR1-TFEB axis may represent a therapeutic strategy to counteract constitutive TFEB activation in cancer-associated conditions.
Project description:Transcriptional regulation of gene expression plays a fundamental role in coordinating molecular and metabolic responses to stress conditions. The stress-responsive Transcription Factor EB (TFEB), the master controller of lysosomal biogenesis and autophagy, is regulated at the post-translational level by the nutrient-sensitive kinase complex TORC1. However, little is known about the transcriptional regulation of TFEB in physiological and pathological conditions. Here, we show that during starvation, the immediate-early gene EGR1 binds to the TFEB promoter and positively regulates TFEB expression. EGR1 depletion dampened TFEB-mediated transcriptional response to starvation and significantly inhibited cell proliferation in cellular and 3D spheroid models of Birt-Hogg-Dube' (BHD) syndrome, a TFEB-driven inherited cancer condition. Consistently, the MEK1/2 inhibitor Trametinib, known to inhibit EGR1 expression, suppressed the proliferation of BHD patient-derived cancer cells, suggesting that pharmacological inhibition of the EGR1-TFEB axis may represent a therapeutic strategy to counteract constitutive TFEB activation in cancer-associated conditions.
Project description:Transcriptional regulation of gene expression plays a fundamental role in coordinating molecular and metabolic responses to stress conditions. The stress-responsive Transcription Factor EB (TFEB), the master controller of lysosomal biogenesis and autophagy, is regulated at the post-translational level by the nutrient-sensitive kinase complex TORC1. However, little is known about the transcriptional regulation of TFEB in physiological and pathological conditions. Here, we show that during starvation, the immediate-early gene EGR1 binds to the TFEB promoter and positively regulates TFEB expression. EGR1 depletion dampened TFEB-mediated transcriptional response to starvation and significantly inhibited cell proliferation in cellular and 3D spheroid models of Birt-Hogg-Dube' (BHD) syndrome, a TFEB-driven inherited cancer condition. Consistently, the MEK1/2 inhibitor Trametinib, known to inhibit EGR1 expression, suppressed the proliferation of BHD patient-derived cancer cells, suggesting that pharmacological inhibition of the EGR1-TFEB axis may represent a therapeutic strategy to counteract constitutive TFEB activation in cancer-associated conditions.
Project description:Transcriptional regulation of gene expression plays a fundamental role in coordinating molecular and metabolic responses to stress conditions. The stress-responsive Transcription Factor EB (TFEB), the master controller of lysosomal biogenesis and autophagy, is regulated at the post-translational level by the nutrient-sensitive kinase complex TORC1. However, little is known about the transcriptional regulation of TFEB in physiological and pathological conditions. Here, we show that during starvation, the immediate-early gene EGR1 binds to the TFEB promoter and positively regulates TFEB expression. EGR1 depletion dampened TFEB-mediated transcriptional response to starvation and significantly inhibited cell proliferation in cellular and 3D spheroid models of Birt-Hogg-Dube' (BHD) syndrome, a TFEB-driven inherited cancer condition. Consistently, the MEK1/2 inhibitor Trametinib, known to inhibit EGR1 expression, suppressed the proliferation of BHD patient-derived cancer cells, suggesting that pharmacological inhibition of the EGR1-TFEB axis may represent a therapeutic strategy to counteract constitutive TFEB activation in cancer-associated conditions.
Project description:Birt-Hogg-Dube (BHD) syndrome patients are uniquely susceptible to all renal tumour subtypes. The underlying mechanism of carcinogenesis is unclear. To study cancer development in BHD, we used human proximal kidney (HK2) cells with short-term and long-term folliculin (FLCN) knockdown. HK2 cells lacking FLCN had an altered transcriptome profile with cell cycle control gene enrichment. G1/S cell cycle checkpoint signaling was compromised with heightened protein levels of cyclin D1 (CCND1) and hyperphosphorylation of retinoblastoma 1 (RB1). Taken together with our proteomic work, our findings indicate that long-term FLCN loss and associated cell cycle defects in BHD patients could contribute to their increased risk of cancer.
Project description:Mutations in the Folliculin (FLCN) gene are responsible for the Birt-Hogg-Dube’ (BHD) syndrome, a rare inherited condition that predisposes affected individuals to develop pulmonary cysts, skin and kidney tumors. However, its involvement in liver carcinogenesis has never been investigated so far. Here we demonstrated that FLCN depletion in mice results in sporadic liver cancer associated with inflammation and fibrosis with features of cholangiocarcinoma (CCA). Total RNA was extracted from n=4 for each experimantal group: Transcriptomic analysis was performed on males and females at 12- and 90-weeks of age.
Project description:Birt-Hogg-Dubè (BHD) syndrome is an inherited condition caused by loss-of-function mutations in the gene encoding the tumor-suppressor protein folliculin (FLCN) and frequently associated with kidney cysts and cancer. FLCN acts as a negative regulator of TFEB and TFE3 transcription factors, master controllers of lysosomal biogenesis and autophagy, by enabling their phosphorylation by the mechanistic Target Of Rapamycin Complex 1 (mTORC1). We previously showed that deletion of TFEB rescued the renal cystic phenotype of kidney-specific Flcn KO mice. Using Flcn/TFEB/TFE3 double and triple KO mice we now show that both TFEB and TFE3 contribute, in a differential and cooperative manner, to kidney cystogenesis. Importantly, silencing of either TFEB or TFE3 rescued tumorigenesis in patient-derived xenografts (PDXs) generated from a kidney tumor of a BHD patient. Furthermore, transcriptome analyses performed in transgenic mice, PDXs and patient tumor samples revealed TFEB/TFE3 downstream targets that may contribute to their tumorigenic activity. Our findings demonstrate in disease-relevant models that TFEB and TFE3 are key drivers of kidney tumorigenesis and suggest novel therapeutic strategies based on the inhibition of these transcription factors.
Project description:Birt-Hogg-Dube (BHD) syndrome is an autosomal dominant disorder characterized by hamartomas of skin follicles, cystic lung disease, and renal neoplasia. Affected individuals carry heterozygous mutations in Folliculin (FLCN), a tumor suppressor gene that becomes biallelically inactivated in kidney tumors by second-hit mutations. Similar to other factors implicated in kidney malignancies, Folliculin has been shown to modulate activation of mammalian target of rapamycin (mTOR). However, its precise in vivo function is largely unknown because germline deletion of Flcn results in early embryonic lethality in animal models. We here describe mice deficient in the newly characterized Folliculin-Interacting Protein 1 (Fnip1). In contrast to Flcn, Fnip1-/- mice develop normally, are not susceptible to kidney neoplasia, but display a striking pro-B cell block that is independent of mTOR activity. We show that this developmental arrest results at least in part from impaired V(D)J recombination and caspase-induced cell death, and that pre-recombined V(D)J and Bcl2 transgenes reconstitute pre-B and mature B cell populations respectively. We also demonstrate that conditional deletion of Flcn recapitulates the pro-B cell arrest of Fnip1-/- mice. Our studies thus demonstrate that the Flcn-Fnip complex deregulated in BHD syndrome is absolutely required for B cell differentiation and that it functions both through mTOR dependent and independent pathways. RNASeq data for two pro-B cell subsets (fraction B and CC') isolated from wt and Fnip1-/- mice
Project description:In Birt-Hogg-Dubé (BHD) syndrome, germline mutations in the Folliculin (FLCN) gene lead to an increased risk of renal cancer. To address if FLCN is involved regulating cellular signaling pathways via protein and receptor phosphorylation we determined comprehensive phosphoproteomic profiles of FLCN-POS and FLCN-NEG human tumor cells (UOK257). UOK257 misses the folliculin (FLCN) gene, whereas UOK 257-2 harbours a lentiviral rescue of the FLCN gene. Experiment performed in duplicate. This data set is linked to PXD021346 that describes phosphoproteomics results for human renal tubular epithelial cells (RPTEC/TERT1).
Project description:Birt-Hogg-Dube (BHD) syndrome is an autosomal dominant disorder characterized by hamartomas of skin follicles, cystic lung disease, and renal neoplasia. Affected individuals carry heterozygous mutations in Folliculin (FLCN), a tumor suppressor gene that becomes biallelically inactivated in kidney tumors by second-hit mutations. Similar to other factors implicated in kidney malignancies, Folliculin has been shown to modulate activation of mammalian target of rapamycin (mTOR). However, its precise in vivo function is largely unknown because germline deletion of Flcn results in early embryonic lethality in animal models. We here describe mice deficient in the newly characterized Folliculin-Interacting Protein 1 (Fnip1). In contrast to Flcn, Fnip1-/- mice develop normally, are not susceptible to kidney neoplasia, but display a striking pro-B cell block that is independent of mTOR activity. We show that this developmental arrest results at least in part from impaired V(D)J recombination and caspase-induced cell death, and that pre-recombined V(D)J and Bcl2 transgenes reconstitute pre-B and mature B cell populations respectively. We also demonstrate that conditional deletion of Flcn recapitulates the pro-B cell arrest of Fnip1-/- mice. Our studies thus demonstrate that the Flcn-Fnip complex deregulated in BHD syndrome is absolutely required for B cell differentiation and that it functions both through mTOR dependent and independent pathways.