MicroRNA profiling identifies miR-2355-5p as a key modulator in Renal Cell Carcinoma tumor growth
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ABSTRACT: Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is one of the first truncal event in clear cell Renal Cell Carcinoma (ccRCC) tumorigenesis. Accumulation of the Hypoxia Induced Factors (HIFα) acquired from VHL loss can promote ccRCC tumorigenesis through regulating microRNAs (miRNA) expression. Here, we performed a miRNA profiling and used high throughput analysis to identify a panel of VHL dependent miRNAs in ccRCC. Validation of these miRNAs uncovered overexpression of miR-2355-5p in ccRCC cell models, and primary tumors. Moreover, we showed a significant increase of circulating miR-2355-5p in plasma from patients with ccRCC. Mechanistically, miR-2355-5p overexpression was confirmed to be HIF-2α-dependent. Indeed, targeting miR-2355-5p with the CRISPR/cas9 system did not only negatively disturbed ccRCC cell’s ability to stimulate angiogenesis, but also decreased cell proliferation and drastically reduced tumor growth in mice xenograft models. Finally, miR-2355-5p pulldown assay identified five tumor suppressor genes, ACO1, BTG2, CMTM4, SLIT2, and WDFY2, as potential targets. All five genes were significantly downregulated in ccRCC tumors and mice xenograft tumors. Results from this research demonstrate the oncogenic ability of miR-2355-5p and shed light on the possible route in which the miRNA controls angiogenesis and tumor growth in VHL-deficient ccRCC
Project description:Renal cell carcinoma (RCC) exhibits some unusual features and genes commonly mutated in cancer are rarely mutated in clear-cell RCC (ccRCC), the most common type. The most prevalent genetic alteration in ccRCC is the inactivation of the tumor suppressor gene VHL. Using whole-genome and exome sequencing we discovered BAP1 as a novel tumor suppressor in ccRCC that shows little overlap with mutations in PBRM1, another recent tumor suppressor. Whereas VHL was mutated in 81% of the patients (142/176), PBRM1 was lost in 58% and BAP1 in 15% of the patients analyzed. All these tumor suppressor genes are located in chromosome 3p, which is partially or completely lost in most ccRCC patients. However, BAP1 but not PBRM1 loss was associated with higher Fuhrman grade and, therefore, poorer outcome. Xenograft tumors (tumorgrafts) implanted orthotopically in mice retained >92% of mutations and exhibited similar DNA copy number alterations to corresponding primary tumors. Thus, after inactivation of VHL, the acquisition of a mutation in BAP1 or PBRM1 defines a different program that might alter the fate of the patient. Our results establish the foundation for an integrated pathological and molecular genetic classification of about 70% of ccRCC patients, paving the way for subtype-specific treatments exploiting genetic vulnerabilities. The genomic DNA of clear-cell renal cell carcinoma (ccRCC) primary tumors, tumors growing in immunodeficient mice (tumorgrafts), and normal samples were labeled and hybridized to Affymetrix SNP arrays 6.0.
Project description:MiRNAs have been shown to alter both protein expression and secretion in different cellular contexts. By combining in vitro, in vivo and in silico techniques, we demonstrated that overexpression of pre-miR-1307 reduced the ability of breast cancer cells to induce endothelial cell sprouting and angiogenesis. However, the molecular mechanism behind this and the effect of the individual mature miRNAs derived from pre-miR-1307 on protein secretion and is largely unknown. Here, we overexpressed miR-1307-3p|0, -3p|1 and 5p|0 in MDA-MB-231 breast cancer cells and assessed the impact of miRNA overexpression on protein secretion by Mass Spectrometry. Unsupervised hierarchical clustering revealed a distinct phenotype induced by overexpression of miR-1307-5p|0 compared to the controls and to the 5’isomiRs derived from the 3p-arm. Together, our results suggest different impacts of miR-1307-3p and miR-1307-5p on protein secretion which is in line with our in vitro observation that miR-1307-5p, but not the isomiRs derived from the 3p-arm reduce endothelial cell sprouting in vitro. Hence these data support the hypothesis that miR-1307-5p is at least partly responsible for impaired vasculature in tumors overexpressing pre-miR-1307.
Project description:Renal cell carcinoma (RCC) exhibits some unusual features and genes commonly mutated in cancer are rarely mutated in clear-cell RCC (ccRCC), the most common type. The most prevalent genetic alteration in ccRCC is the inactivation of the tumor suppressor gene VHL. Using whole-genome and exome sequencing we discovered BAP1 as a novel tumor suppressor in ccRCC that shows little overlap with mutations in PBRM1, another recent tumor suppressor. Whereas VHL was mutated in 81% of the patients (142/176), PBRM1 was lost in 58% and BAP1 in 15% of the patients analyzed. All these tumor suppressor genes are located in chromosome 3p, which is partially or completely lost in most ccRCC patients. However, BAP1 but not PBRM1 loss was associated with higher Fuhrman grade and, therefore, poorer outcome. Xenograft tumors (tumorgrafts) implanted orthotopically in mice exhibited similar gene expression profiling to corresponding primary tumors. Gene expression profiling of tumors and tumorgrafts displayed different signatures for BAP1- and PBRM1-deficient samples. Thus, after inactivation of VHL, the acquisition of a mutation in BAP1 or PBRM1 defines a different program that might alter the fate of the patient. Our results establish the foundation for an integrated pathological and molecular genetic classification of about 70% of ccRCC patients, paving the way for subtype-specific treatments exploiting genetic vulnerabilities. The RNA of clear-cell renal cell carcinoma (ccRCC) primary tumors, tumors growing in immunodeficient mice (tumorgrafts), and normal kidney cortices were labeled and hybridized to Affymetrix Human Genome U133 Plus 2.0 arrays.
Project description:Besides the truncal VHL mutations, ccRCC is characterized by upregulated MTOR signals from both preclinical and clinical studies. To understand how upregulated MTOR signals cooperate with VHL loss in promoting kidney tumorigenesis, we generated kidney-specific deletion of Vhl and Tsc1 (Vhl;Tsc1 cDKO) in mice. The mice showed decreased life span with maximal age of 11 weeks, bilateral polycystic kidney diseases from ~3 weeks and multifocal solid renal cell carcinoma with eosinophilic cytoplasm and grade 2-3 from 7 weeks old. The mouse tumors resemble histology of the human kidney tumors with VHL and TSC1 mutations. To understand the mechanism of how Tsc1 loss cooperates with Vhl loss in promoting tumorigenesis, we performed transcriptomic, metabolomic and immunohistochemical profilings of renal cortices from age-matched wild-type, Vhl or Tsc1 single knockout, and Vhl;Tsc1 cDKO mice. Tsc1 loss cooperates with Vhl loss by augmenting the HIF1 transcriptional output, as well as altering the glutamine/glutamate metabolism, urea cycle, glycogen metabolism, and activating NRF2 signaling pathways which reprogram the cells to counteract the high oxidative stress associated with the proliferation. Our study reports a ccRCC mouse model recapitulating human ccRCC with same genetic background, provides mechanistic insights concerning cooperation between upregulated mTORC1 signals and VHL loss, generates in vivo reagents for studying ccRCC, and implicates potential clinical values.
Project description:Clear cell renal cell carcinomas (ccRCC) are characterized by arm-wide chromosomal alterations. Loss at 14q is associated with disease aggressiveness in ccRCC, which responds poorly to chemotherapeutics. The 14q locus contains one of the largest miRNA clusters in the human genome; however, little is known about the contribution of these miRNAs to ccRCC pathogenesis. In this regard, we investigated the expression pattern of selected miRNAs at the 14q32 locus in TCGA kidney tumors and in ccRCC cell lines. We validated that the miRNA cluster is downregulated in ccRCC (and cell lines) as well as in papillary kidney tumors relative to normal kidney tissues and primary renal proximal tubule epithelial (RPTEC) cells. We demonstrated that agents modulating expression of DNMT1 (e.g., 5-Aza-deoxycytidine) could modulate miRNA expression in ccRCC cell lines. Lysophosphatidic acid (LPA, a Lysophospholipid mediator elevated in ccRCC) not only increased labile iron content but also modulated expression of 14q32 miRNAs. Through an overexpression approach targeting a subset of 14q32 miRNAs (specifically at subcluster A: miR-431, miR-432, miR-127, and miR-433) in 769-P cells, we uncovered changes in cellular viability and claudin-1, a tight junction marker. A global proteomic approach was implemented using these miRNA overexpressing cell lines which uncovered ATXN2 as a highly downregulated target, which has a role in chronic kidney disease pathogenesis. Collectively, these findings support a contribution of miRNAs at 14q32 in ccRCC pathogenesis.
Project description:The deregulation of microRNAs (miRNAs) has been demonstrated to be involved in tumor angiogenesis and offers opportunities for a new therapeutic approach. However, effective miRNA delivery systems are needed for such approaches to be successful. In this study, miRNA profiling of patient data sets, along with in vitro and in vivo experiments, revealed that miR-204-5p could promote angiogenesis in ovarian tumors through THBS1. To identify potential molecular mechanisms by which miR-204-5p exerts its pro-angiogenic effects, we performed a gene expression microarray of HeyA8-MDR cells following treatment with miR-204-5p-inh.
Project description:Altered metabolism is an important part of malignant transformation of tumor cells. Oncogenic transformation may reprogram tumor metabolism and render tumor cells addicted to extracellular nutrients. Such nutrient addictions associated with oncogenic mutations may offer therapeutic opportunities; however, it remains difficult to predict these nutrient addictions. Here, we performed a nutrigenetic screen to determine the phenotypes of isogenic pairs of clear-cell renal cancer cells (ccRCC) with or without VHL upon the deprivation of individual amino acids. We identified that cystine deprivation triggered rapid programmed necrosis in VHL-deficient RCC, but not in their VHL-restored counterparts. Similar cystine addiction was also observed in VHL-deficient primary RCC tumors cells. Blockage of cystine uptake significantly delayed xenograft growth of ccRCC. Importantly, cystine deprivation triggered similar metabolic changes regardless of VHL status. Therefore, metabolic differences due to cystine deprivation are not different enough to readily explain the distinct fate of life vs. death in VHL-deficient and restored cell.. Instead, we found that increased levels of TNFα associated with VHL loss in the VHL-deficient RCC force them to rely on intact RIPK1 to inhibit apoptosis. However, this pre-existing elevated TNFα in the VHL-deficient ccRCC renders these cells susceptible to the necrosis signaling triggered by cystine deprivation. In addition, we identified that cystine-deprived necrosis in VHL-deficient RCC depends on reciprocal amplification of the Src-p38-Noxa signaling and TNFα-RIP1/3-MLKL necrosis pathways that culminate in MLKL oligomerization and programmed necrosis. Together, our data reveal that the contextual cystine-addictions in VHL-deficient ccRCC is dependent on activating pre-existing oncogenic pathways to trigger programmed necrosis. RNA was extracted by RNAeasy kits (Qiagen) from the RCC4 Vec and VHL-reconstituted cells which were exposed to the control full DMEM or cystine deprived DMEM media for 6 hours (three replicates in each condition).
Project description:Clear cell renal cell carcinoma (ccRCC) is an aggressive disease characterized by dysregulated hypoxia signaling, metabolic defects, and a complex tumor microenvironment (TME) highly enriched in lymphoid and myeloid immune cells. Loss of the oxygen sensing gene, von Hippel Lindau (VHL), is a critical early event in ccRCC pathogenesis and promotes stabilization of hypoxia inducible factors (HIF) that upregulate pro-growth signaling pathways, including angiogenesis and aerobic glycolysis. However, whether VHL loss in cancer cells impacts the composition, metabolism, or function of immune cells in the TME remains unclear. Using Vhl wildtype (WT) and knockout (KO) in vivo murine kidney cancer models, we found that Vhl KO tumors were less proliferative and more infiltrated by immune cells. Tumor-associated macrophages (TAM) demonstrated enhanced proinflammatory transcriptional signatures from Vhl deficient tumors, and intratumoral myeloid cells residing in the Vhl KO TME showed increased in vivo glucose consumption. Vhl loss did not confer increased in vivo glucose uptake in cancer cells or lymphocytes, or detectable changes in metabolites in the interstitial fluid. Mechanistically, enhanced secretion of the chemokine, CX3CL1, was observed in Vhl KO cancer cells and its cognate receptor, CX3CR1, was significantly elevated on myeloid cells residing in the TME of Vhl deficient tumors. Human ccRCC tumors exhibit high expression of CX3CL1 and CX3CR1 as well as enhanced myeloid metabolism and proinflammatory properties. Here, we identify the importance of cancer cell-specific genetic features to drive environmental reprograming and shape the tumor immune landscape and identify a potential therapeutic target in the treatment of ccRCC.
Project description:Renal cancer accounts for 2% to 3% of all adult malignancies in the US. In 2011 more than 64,770 new cases and 13,000 deaths were reported and the incidence is steadily increasing by 2.5% per year. Clear cell renal carcinoma (ccRCC) represents the majority (85% to 90%) of adult kidney cancers and is the most malignant. This cancer is characterized by an early loss of the von Hippel-Lindau tumor suppressor (VHL) on short arm of chromosome 3 in the majority of tumors (80%). It is a classic knowledge that loss of VHL results in an increased accumulation and activity of the hypoxia-inducible transcription factor (HIF), which in turns activates expression of genes promoting tumor growth. In that respect, induction of angiogenic factors induces blood flow through the tumors and delivery of nutrients and oxygen to cancer cells, while induction of genes inducing anaerobic glycolysis supports adaptation to reduced nutrients availability and shifts towards metabolic pathways promoting tumor growth. Recently we have discovered another tumor suppressing pathway regulated by VHL. We found that VHL is a major regulator of the process of macroautophagy (autophagy) (ref). We identified that VHL induces expression of a microRNA, miR-204, which in turn inhibits activity of a major regulator required for the formation of autophagosome, LC3B. LC3B-mediated autophagy is necessary for the ccRCC tumor growth, and inhibition of this process by VHL and miR-204 significantly contributes to the tumor suppression. Most importantly, we discovered that VHL by inhibiting activity of HIF, induced expression and activity of an LC3B paralog, LC3C. In contrast to LC3B, LC3C acts as a tumor suppressor, indicating the specificity and complexity of different autophagic programs. Integrating these novel data with the established role of VHL in regulating angiogenesis produces a more global picture of VHL as a master tumor suppressor that regulates nutrient access for renal cancer cells from both extracellular and intracellular sources. In the process of searching for other genes induced by VHL that could participate in the tumor suppressing activity of VHL, we discovered that reconstitution of VHL in RCC cells induces enrichment of genes expressed from the Smith-Magenis locus (SM), located on the short arm of chromosome 17p11.2. Smith-Magenis syndrome is a complex neurobehevioural disorder, characterized by intellectual impairment, craniofacial and skeletal anomalies and sleep disturbance. Recently, deletions or mutations of one specific gene in the SM locus, RAI1, (retinoic acid induced 1), were shown to be responsible for the syndrome. Interestingly, this locus contains another kidney tumor suppressor gene, folliculin (FLCN), of which activity is lost in the genetic dominant disorder, Birt-Hogg-Dube syndrome (BHD). BHD is characterized by skin fibrofolliculomas, pulmonary cysts and spontaneous pneumothorax, as well as renal cancer of mixed histological types, including chromophobe, oncocytic, clear cell and papillary type. Here we show that VHL regulates expression of FLCN, and in turn FLCN contributes to the VHL-mediated suppression of tumor growth. Two-condition experiment, VHL(-) vs. VHL(+). 4 biological replicates in each group. Two dual-channel arrays with VHL(+) on Cy5 and VHL(-) on Cy3, and two dual-channel arrays with flipped samples.
Project description:VHL loss is the most common genetic alteration event in ccRCC. By profiling histone modifications from VHL-deficient ccRCC primary tumors and cell lines, we identifed tumor-associated promoters and enhancers. We next investigate whether VHL restoration alters tumor associated promoters and enhancers. We compared H3K27ac ChIP-seq with and without VHL restoration in 786-O cells. Restoration of wild-type VHL significantly altered a subset of tumor enhancers but affected promoters to a less extent.