Project description:Retinoblastoma (Rb) is a deadly childhood eye cancer that is classically initiated by inactivation of the RB1 tumor suppressor. Clinical management continues to rely on nonspecific chemotherapeutic agents that are associated with treatment resistance and toxicity. Here, we analyzed 103 whole exomes, 16 whole transcriptomes, 5 single-cell transcriptomes, and 4 whole genomes from primary Rb tumors to identify novel Rb dependencies. Several recurrent genomic aberrations implicate estrogen-related receptor gamma (ESRRG) in Rb pathogenesis. RB1 directly interacts with and inhibits ESRRG, and RB1 loss uncouples ESRRG from negative regulation. ESRRG regulates genes involved in retinogenesis and oxygen metabolism in Rb cells. ESRRG is preferentially expressed in hypoxic Rb cells in vivo. Depletion or inhibition of ESRRG causes marked Rb cell death which is exacerbated in hypoxia. These findings reveal a novel dependency of Rb cells on ESRRG, and they implicate ESRRG as a potential therapeutic vulnerability in Rb.
Project description:Retinoblastoma (Rb), the most prevalent intraocular malignant tumor in children with global survival rate less than 30%, is mainly caused by the deficiency of the tumor suppressor RB1. A line of evidence have shown that local inflammation and immune escape play important roles in the occurrence of Rb, however the underlying mechanism remains unclear. We hypothesize that the unique neuroimmune cell type, retinal microglia, has a vital role in the Rb pathogenesis. In this study, we differentiated microglia cells (iMGs) from established induced pluripotent stem cells (iPSCs) derived from a retinoblastoma patient with the defined RB1 mutations. We investigated the function of RB1 in innate immune response of microglia and found that the expression of interleukins and chemokines, especially interleukin 6 and TNF-α, were highly upregulated in LPS-stimulated RB1 deficient iMGs, which enhanced innate immune responses and created a pro-inflammation environment. These findings demonstrated that RB1 is indispensable to maintain microglia function in innate immunity and its deficiency leads to enhanced inflammation responses, which may accelerate tumor growth and malignancy. This study provides new insights for pathological mechanism and immunotherapeutic target of retinoblastoma.
Project description:In this study, we generated a human genome-wide map of DNA lesions induced by ultraviolet (UV) radiation in retinoblastoma knockout (RB1 KO) cells. Interestingly, we observed increased carcinogen susceptibility in closed HI-C domainS, pericentric and subtelomeric regions in RB1 KO. We also observed increased susceptibility at cancer driver loci such as TERT and TPTE. These loci are highly mutated in melanoma. Finally, we proposed that loss of tumor suppressor function can alter carcinogen susceptibility, and subsequently the mutation frequency of the genome.
Project description:Background Retinoblastoma is a pediatric eye cancer associated with RB1 loss or MYCN amplification (RB1+/+MYCNA). There are controversies concerning the existence of molecular subtypes within RB1-/- retinoblastoma. To test whether these molecular subtypes exist, we performed molecular profiling. Methods Genome-wide mRNA expression profiling was performed on 76 primary human retinoblastomas. Expression profiling was complemented by genome-wide DNA profiling and clinical, histopathological, and ex vivo drug sensitivity data. Findings RNA and DNA profiling identified major variability between retinoblastomas. While gene expression differences between RB1+/+MYCNA and RB1-/- tumors seemed more dichotomous, differences within the RB1-/- tumors were gradual. Tumors with high expression of a photoreceptor gene signature were highly differentiated, smaller in volume and diagnosed at younger age compared to tumors with low photoreceptor signature expression. Tumors with lower photoreceptor expression showed increased expression of genes involved in M-phase and mRNA and ribosome synthesis and increased frequencies of somatic copy number alterations. Interpretation Molecular, clinical and histopathological differences between RB1-/- tumors are best explained by tumor progression, reflected by a gradual loss of differentiation and photoreceptor expression signature. Since copy number alterations were more frequent in tumors with less photoreceptorness, genomic alterations might be drivers of tumor progression. Fresh frozen material from 76 primary human retinoblastoma samples were profiled with Affymetrix human genome u133 plus 2.0 PM microarray
Project description:MYCNOS (MYCN opposite strand) is co-amplified with MYCN in pediatric cancers including retinoblastoma. MYCNOS encodes several RNA variants whose functions have not been elucidated in retinoblastoma. Here, we attempted to decipher the role of MYCNOS variant 1 (MYCNOS1) on the activity of MYCN-amplified retinoblastoma. We observed that MYCNOS1 supports progression of retinoblastoma. Inhibition of MYCNOS1 expression may be needed to suppress MYCN activity when treating MYCN-amplified cancers without RB1 mutation.
Project description:We used novel genetically engineered mouse models to investigate the role of HELLS during tumorigenesis. Loss of HELLS drastically decreased the incidence of retinoblastoma, delayed tumor progression, and increased overall survival. Tumors from Rb1/p107 DKO and Rb1/p107/Hells TKO mice were analyzed for gene expression using RNA-seq.
Project description:Breast cancers can be classified using whole genome expression into distinct subtypes that show differences in patient prognosis. One of these groups, the basal-like carcinomas, are poorly differentiated, highly metastatic, and genomically unstable. These tumors also contain specific genetic alterations with one example being frequent p53 mutations. The loss of the tumor suppressor gene encoded by the retinoblastoma (RB1) locus is a well-characterized occurrence in many tumor types, however, its role in breast cancer is less clear with many reports demonstrating a Loss of Heterozygosity (LOH) that does not correlate with loss of RB1 protein expression. Here we report that LOH of the RB1 locus was observed at a high frequency in basal-like and luminal B tumors. These tumors also concurrently have low expression of RB1 mRNA as assessed by DNA microarray. As in previous reports, we also did not see a significant correlation between RB1 LOH and protein expression as measured by immunohistochemistry (IHC). p16INK4a, however, was highly expressed both by microarray and IHC, in basal-like tumors only presumably due to a previously reported feedback loop caused by RB1 loss. These results suggest that the functional loss of RB1 is a common event in the progression of basal-like and luminal B breast tumors, which may play a key role in dictating therapeutic responses Keywords: reference x sample Comparison of reference samples against treatment
Project description:We used novel genetically engineered mouse models to investigate the role of HELLS during tumorigenesis. Loss of HELLS drastically decreased the incidence of retinoblastoma, delayed tumor progression, and increased overall survival. Retinae from Rb1/p107 DKO and Rb1/p107/Hells TKO mice at postnatal day 21 were analyzed for gene expression using RNA-seq.