Rb Tumors Research Articles

Depleted hexokinase1 and lack of AMPKα activation favor OXPHOS-dependent energetics in retinoblastoma tumors

Lack of retinoblastoma (Rb) protein causes aggressive intraocular retinal tumors in children. Recently, Rb tumors have been shown to have a distinctly altered metabolic phenotype, such as reduced expression of glycolytic pathway proteins alongside altered pyruvate and fatty acid levels. In this study, we demonstrate that loss of hexokinase 1(HK1) in tumor cells rewires their metabolism allowing enhanced oxidative phosphorylation-dependent energy production. We show that rescuing HK1 or retinoblastoma protein 1 (RB1) in these Rb cells reduced cancer hallmarks such as proliferation, invasion, and spheroid formation and increased their sensitivity to chemotherapy drugs. Induction of HK1 was accompanied by a metabolic shift of the cells to glycolysis and a reduction in mitochondrial mass. Cytoplasmic HK1 bound Liver Kinase B1 and phosphorylated AMP-activated kinase-α (AMPKα Thr172), thereby reducing mitochondria-dependent energy production. We validated these findings in tumor samples from Rb patients compared to age-matched healthy retinae. HK1 or RB1 expression in Rb-/- cells led to a reduction in their respiratory capacity and glycolytic proton flux. HK1 overexpression reduced tumor burden in an intraocular tumor xenograft model. AMPKα activation by AICAR also enhanced the tumoricidal effects of the chemotherapeutic drug topotecan in vivo. Therefore, enhancing HK1 or AMPKα activity can reprogram cancer metabolism and sensitize Rb tumors to lower doses of existing treatments, a potential therapeutic modality for Rb.

Retinoblastoma gene expression profiling based on bioinformatics analysis

BackgroundRetinoblastoma (RB) is frequently occurring malignant tumors that originate in the retina, and their exact cause and development mechanisms are yet to be fully comprehended. In this study, we identified possible biomarkers for RB and delved into the molecular mechanics linked with such markers.MethodsIn this study GSE110811 and GSE24673 were analyzed. Weighted gene co-expression network analysis (WGCNA) was applied to screen modules and genes associated with RB. By overlapping RB-related module genes with differentially expressed genes (DEGs) between RB and control samples, differentially expressed retinoblastoma genes (DERBGs) were acquired. A gene ontology (GO) enrichment analysis and a kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis were conducted to explore the functions of these DERBGs. To study the protein interactions of DERBGs, a protein–protein interaction (PPI) network was constructed. Hub DERBGs were screened using the least absolute shrinkage and selection operator (LASSO) regression analysis, as well as the random forest (RF) algorithm. Additionally, the diagnostic performance of RF and LASSO methods was evaluated using receiver operating characteristic (ROC) curves and single-gene gene set enrichment analysis (GSEA) was conducted to explore the potential molecular mechanisms involved with these Hub DERBGs. In addition, the competing endogenous RNA (ceRNA) regulatory network of Hub DERBGs was constructed.ResultAbout 133 DERBGs were found to be associated with RB. GO and KEGG enrichment analyses revealed that the important pathways of these DERBGs. Furthermore, the PPI network revealed 82 DERBGs interacting with each other. By RF and LASSO methods, PDE8B, ESRRB, and SPRY2 were identified as Hub DERBGs in patients with RB. From the expression assessment of Hub DERBGs, it was found that the levels of expression of PDE8B, ESRRB, and SPRY2 were significantly decreased in the tissues of RB tumors. Secondly, single-gene GSEA revealed a connection between these 3 Hub DERBGs and oocyte meiosis, cell cycle, and spliceosome. Finally, the ceRNA regulatory network revealed that hsa-miR-342-3p, hsa-miR-146b-5p, hsa-miR-665, and hsa-miR-188-5p may play a central role in the disease.ConclusionHub DERBGs may provide new insight into RB diagnosis and treatment based on the understanding of disease pathogenesis.

Enhanced Epithelial-to-Mesenchymal Transition and Chemoresistance in Advanced Retinoblastoma Tumors Is Driven by miR-181a.

Simple SummaryOur study identified the differential expression and potential effects of microRNAs in retinoblastoma vs. pediatric retina and advanced vs. non-advanced tumors. We provide evidence of the epithelial–mesenchymal transition (EMT) and chemoresistance programs in advanced tumors, which were potentially attributed to miR-181a-5p. We analyzed the differential expression of relevant EMT- and chemoresistance-related proteins in advanced vs. non-advanced tumors and chemotherapy-adapted Y79 cells to assess whether EMT and chemoresistance mechanisms were linked. We further examined the possible role of TGFβ as a potential regulator of such differences and highlighted the role of miR-181a-5p in EMT- and chemoresistance-related gene expression and drug sensitivity.Advanced retinoblastoma (Rb) tumors display high metastatic spread to distant tissues, causing a potent threat to vision and life. Through transcriptomic profiling, we discovered key upregulated genes that belonged to the epithelial–mesenchymal transition (EMT) and chemotherapy resistance pathways in advanced Rb tumors. Through in vitro models, we further showed that Rb null tumor cells under prolonged chemo drug exposure, acquires a metastasis-like phenotype through the EMT program mediated by ZEB1 and SNAI2 and these cells further acquires chemotherapeutic resistance through cathepsin-L- and MDR1-mediated drug efflux mechanisms. Using a miRNA microarray, we identified miR-181a-5p as being significantly reduced in advanced Rb tumors, which was associated with an altered EMT and drug-resistance genes. We showed that enhancing miR-181a-5p levels in Rb null chemo-resistant sublines reduced the ZEB1 and SNAI2 levels and halted the mesenchymal transition switch, further reducing the drug resistance. We thus identified miR-181a-5p as a therapeutically exploitable target for EMT-triggered drug-resistant cancers that halted their invasion and migration and sensitized them to low-dose chemotherapy drugs.

RB1 loss triggers dependence on ESRRG in retinoblastoma.

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, 20 whole transcriptomes, 5 single-cell transcriptomes, and 4 whole genomes from primary Rb tumors to identify previously unknown 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 previously unidentified dependency of Rb cells on ESRRG, and they implicate ESRRG as a potential therapeutic vulnerability in Rb.

Abstract 2499: Identifying DNA methylation signatures of retinoblastoma via aqueous humor, a novel ocular liquid biopsy

Abstract Introduction: Retinoblastoma (Rb) is the most common childhood intraocular cancer. Tissue biopsy of Rb can cause tumor spread, so it is contraindicated. We demonstrated that aqueous humor (AH), an ocular fluid, is a high yield liquid biopsy enabling in vivo detection of tumor-derived cell free DNA (cfDNA) thus overcoming the contraindication to biopsy. Prognostic genomic cfDNA biomarkers in Rb AH enables objective real time disease monitoring. In ~13% of Rb, tumor progression is driven by epigenetic deregulation of tumor-promoting pathways without detectable genomic alterations. However, epigenetic studies have been done only on tumor from surgically removed eyes. The frequency and effect of epigenomic regulation in eyes that have been saved with therapy is not clear due to no access to in vivo tumor. Therefore, epigenetic analysis of AH cfDNA is highly desired to understand the broader spectrum of Rb tumorigenesis and prognosis. Materials and Methods: 16 AH samples and 4 Rb tumors from 12 patients with 14 Rb eyes were included in the study. We conducted global DNA methylation profiling of tumor tissues from surgically removed Rb eyes, AH samples collected from different clinical stages with different treatment outcomes using the Illumina Infinium EPIC DNA methylation BeadArray platform. Publicly available DNA methylation data of normal retina, Rb eyes, and Rb patients were obtained from Gene Expression Omnibus (GEO, GSE57362) for cell type DNA methylation comparisons. Results: Our preliminary studies revealed a high degree of concordance in genome-wide differential DNA methylation patterns between paired AH and tumor samples. Integrating our data with large public datasets, we identified reliable RB DNA methylation signatures in cfDNA that have potential diagnostic and prognostic values. We also identified hypermethylation at RB1 promoter, which suggested RB1 is druggable to DNA methylation inhibitors. By integrating DNA methylation data with gene expression data, we identified over 300 differentially expressed genes potentially regulated by DNA methylation change. Pathway analysis indicated several tumor suppressor pathways (e.g., RB1 and P53 pathways) were suppressed and some oncogenic pathways were activated (e.g., E2F pathways). Conclusions: Our study sets the stage for exploiting epigenetic markers in AH and identifying potential therapeutic targets to improve the clinical management of patients with RB. Citation Format: Liya Xu, Hongtao Li, Dan Weisenberger, Gangning Liang, Jesse Berry. Identifying DNA methylation signatures of retinoblastoma via aqueous humor, a novel ocular liquid biopsy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2499.

PRB-Depleted Pluripotent Stem Cell Retinal Organoids Recapitulate Cell State Transitions of Retinoblastoma Development and Suggest an Important Role for pRB in Retinal Cell Differentiation.

Retinoblastoma (Rb) is a childhood cancer of the developing retina, accounting for up to 17% of all tumors in infancy. To gain insights into the transcriptional events of cell state transitions during Rb development, we established 2 disease models via retinal organoid differentiation of a pRB (retinoblastoma protein)-depleted human embryonic stem cell line (RB1-null hESCs) and a pRB patient-specific induced pluripotent (iPSC) line harboring a RB1 biallelic mutation (c.2082delC). Both models were characterized by pRB depletion and accumulation of retinal progenitor cells at the expense of amacrine, horizontal and retinal ganglion cells, which suggests an important role for pRB in differentiation of these cell lineages. Importantly, a significant increase in the fraction of proliferating cone precursors (RXRγ+Ki67+) was observed in both pRB-depleted organoid models, which were defined as Rb-like clusters by single-cell RNA-Seq analysis. The pRB-depleted retinal organoids displayed similar features to Rb tumors, including mitochondrial cristae aberrations and rosette-like structures, and were able to undergo cell growth in an anchorage-independent manner, indicative of cell transformation in vitro. In both models, the Rb cones expressed retinal ganglion and horizontal cell markers, a novel finding, which could help to better characterize these tumors with possible therapeutic implications. Application of Melphalan, Topotecan, and TW-37 led to a significant reduction in the fraction of Rb proliferating cone precursors, validating the suitability of these in vitro models for testing novel therapeutics for Rb.

Identification of Epigenetically Modified Hub Genes and Altered Pathways Associated With Retinoblastoma.

Retinoblastoma (Rb) is the most common childhood malignancy initiated by biallelic mutation in RB1 gene and driven by various epigenetic events including DNA methylation and microRNA dysregulation. Hence, understanding the key genes that are critically modulated by epigenetic modifications in RB1 −/− cells is very important to identify prominent biomarkers and therapeutic targets of Rb. In this study, we for the first time have integrated various Rb microarray NCBI-GEO datasets including DNA Methylation (GSE57362), miRNA (GSE7072) and mRNA (GSE110811) to comprehensively investigate the epigenetic consequences of RB loss in retinoblastoma tumors and identify genes with the potential to serve as early diagnostic markers and therapeutic targets for Rb. Interestingly, the GEO2R and co-expression network analysis have identified three genes namely E2F3, ESR1, and UNC5D that are significantly deregulated by modified DNA methylation, mRNA and microRNA expression in Rb tumors. Due to their recognition in all epigenetic, transcriptomic, and miRNA datasets, we have termed these genes as “common genes”. The results of our integrative bioinformatics analysis were validated in vitro by studying the gene and protein expression of these common genes in Y79, WERI-Rb-1, Rb cell lines and non-tumorigenic retinal pigment epithelial cell line (hTERT-RPE). The expression of E2F3 and UNC5D were up-regulated and that of ESR1 was down-regulated in Rb tumor cells when compared to that in non-tumorigenic hTERT-RPE cells. More importantly, UNC5D, a potent tumor suppressor gene in most cancers is significantly up-regulated in Y79 and Weri Rb1 cells, which, in turn, questions its anti-cancer properties. Together, our study shows that E2F3, ESR1, and UNC5D may be crucially involved in Rb tumorigenesis and possess the potential to act as early diagnostic biomarkers and therapeutic targets of Rb.

Multifunctional Polymeric Nanoparticles for Chemo/Phototheranostics of Retinoblastoma.

Retinoblastoma (Rb) is the most critical and severe intraocular malignancy occurring in children. The clinical management of retinoblastoma is still challenging due to failure in early detection and control despite the advancements in medical strategies. Early-stage Rb tumors do not occupy major visual fields, so chemo/photothermal therapy (PTT) with biocompatible materials can be a practical approach. Herein, we report multifunctional polymeric nanoparticles (PNPs) entrapped with an FDA-approved anticancer drug, Palbociclib (PCB), and a near-infrared dye, IR820 (IR), as chemo/photothermal agents. These PCB/IR PNPs were evaluated for the combinational effect in the retinoblastoma cell line. Further, the in vivo photoacoustic imaging efficacy and acute toxicity profile of the PNPs were studied in a mice model. The results indicated that the PCB/IR PNPs exhibited a significant cytotoxic effect (86.5 ± 2.3%) in Y79 cell lines than the respective control groups upon exposure to NIR light. Qualitative and quantitative analyses indicated that PCB/IR PNPs with NIR light induction resulted in DNA damage followed by apoptosis. PCB/IR PNPs, when tested in vivo, showed optimal photoacoustic signals. Thus, the combination of PCB and PTT can emerge as a translational modality for retinoblastoma therapy.

Dissecting the Transcriptional and Chromatin Accessibility Heterogeneity of Proliferating Cone Precursors in Human Retinoblastoma Tumors by Single Cell Sequencing-Opening Pathways to New Therapeutic Strategies?

PurposeRetinoblastoma (Rb) is a malignant neoplasm arising during retinal development from mutations in the RB1 gene. Loss or inactivation of both copies of RB1 results in initiation of retinoblastoma tumors; however, additional genetic changes are needed for the continued growth and spread of the tumor. Ex vivo research has shown that in humans, retinoblastoma may initiate from RB1-depleted cone precursors. Notwithstanding, it has not been possible to assess the full spectrum of clonal types within the tumor itself in vivo and the molecular changes occurring at the cells of origin, enabling their malignant conversion. To overcome these challenges, we have performed the first single cell (sc) RNA- and ATAC-Seq analyses of primary tumor tissues, enabling us to dissect the transcriptional and chromatin accessibility heterogeneity of proliferating cone precursors in human Rb tumors.MethodsTwo Rb tumors each characterized by two pathogenic RB1 mutations were dissociated to single cells and subjected to scRNA-Seq and scATAC-Seq using the 10× Genomics platform. In addition, nine human embryonic and fetal retina samples were dissociated to single cells and subjected to scRNA- and ATAC-Seq analyses. The scRNA- and ATAC-Seq data were embedded using Uniform Manifold Approximation and Projection and clustered with Seurat graph–based clustering. Integrated scATAC-Seq analysis of Rb tumors and human embryonic/fetal retina samples was performed to identify Rb cone enriched subclusters. Pseudo time analysis of proliferating cones in the Rb samples was performed with Monocle. Ingenuity Pathway Analysis was used to identify the signaling pathway and upstream regulators in the Rb cone–enriched subclusters.ResultsOur single cell analyses revealed the predominant presence of cone precursors at different stages of the cell cycle in the Rb tumors and among those identified the G2/M subset as the cell type of origin. scATAC-Seq analysis identified two Rb enriched cone subclusters, each characterized by activation of different upstream regulators and signaling pathways, enabling proliferating cone precursors to escape cell cycle arrest and/or apoptosis.ConclusionsOur study provides evidence of Rb tumor heterogeneity and defines molecular pathways that can be targeted to define new treatment strategies.

Adhesion G protein-coupled receptor, ELTD1, is a potential therapeutic target for retinoblastoma migration and invasion

BackgroundPrognosis for pediatric metastatic Retinoblastoma (Rb) is poor and current therapies are limited by high systemic toxicity rates and insufficient therapeutic efficacy for metastatic Rb. Tumor dissemination to the brain is promoted by the heterogeneous adhesive and invasive properties of Rb cells within the tumor. In this study we evaluate, for the first time, the expression, and roles of the ELTD1 and GPR125 adhesion G protein-coupled receptors (GPCRs) in Rb cell migration, viability and invasion.MethodsWe characterized the RNA expression of adhesion-GPCRs in 64 Rb tumors compared to 11 fetal retinas using the database from the Childhood Solid Tumor Network from St Jude Children’s Research Hospital. The role of ELTD1 and GPR125 in Rb were investigated ex vivo by microarray analysis, in vitro by cell viability, Western blot and migration assays, in addition to imaging of the subcellular localization of the GPCRs. To elucidate their role in vivo we utilized siRNA technology in an established Rb orthotopic xenograft murine model.ResultsOur investigation demonstrates, for the first time, that ELTD1 but not GPR125, is significantly increased in Rb tumors compared to fetal retinas. We utilized established the Rb cell lines Y79 and Weri-Rb-1, which represent an aggressive, metastatic, and non-metastatic phenotype, respectively, for the in vitro analyses. The studies demonstrated that ELTD1 is enriched in Weri-Rb-1 cells, while GPR125 is enriched in Y79 cells. The measured differences extended to their subcellular localization as ELTD1 labeling displayed punctate clusters in cell-to-cell adhesion sites of Weri-Rb-1 cells, while GPR125 displayed a polarized distribution in Y79 cells. Lastly, we demonstrated the lack of both adhesion receptors does not affect Rb cell viability, yet inhibition of ELTD1 decreases Y79 cell migration in vitro and invasion in vivo.ConclusionTaken together, our data suggest that ELTD1, is a potential target to prevent extraocular Rb. The results within establish ELTD1 as a potential therapeutic target for metastatic Rb.

Ophthalmic artery catheterization for retinoblastoma treatment: does reflux affect tumor response?

BackgroundIntra-arterial chemotherapy (IAC) for retinoblastoma (Rb) has been established as a primary treatment for the disease. To determine whether the presence of reflux into the ICA is associated with tumor...

Association of Biomarkers for Human Papillomavirus With Survival Among Adults With Barrett High-grade Dysplasia and Esophageal Adenocarcinoma

The presence of high-risk human papillomavirus (HPV) has been associated with a favorable outcome in Barrett high-grade dysplasia (HGD) and esophageal adenocarcinoma (EAC). Nevertheless, the prognostic significance of other HPV-related biomarkers (ie, retinoblastoma protein [pRb], cyclin D1 [CD1], minichromosome maintenance protein [MCM2] and Ki-67) is unknown. To examine the association between HPV-related biomarkers and survival in adult patients with Barrett HGD and EAC. This retrospective case-control study examined the hypothesis that the HPV-related cell cycle markers (pRb, CD1, and Ki-67) and the viral surrogate marker (MCM2) may be associated with a favorable prognosis in Barrett HGD and EAC. Pretreatment biopsies were used for HPV DNA determination via polymerase chain reaction and immunohistochemistry for the HPV-related biomarkers. Recruitment of patients occurred in secondary and tertiary referral centers, with 151 patients assessed for eligibility. The study period was from December 1, 2002, to November 28, 2017, and the dates of analysis were from September 9, 2011, to November 28, 2017. Disease-free survival and overall survival. Of 151 patients assessed for eligibility, 9 were excluded. Among the 142 patients with Barrett HGD or EAC (126 [88.7%] men; mean [SD] age, 66.0 [12.1] years; 142 [100%] white), 37 were HPV positive and 105 were HPV negative. No association with disease-free survival was noted for pRb, CD1, Ki-67, and MCM2. In regard to overall survival, only low expression of CD1 had a favorable prognosis (hazard ratio [HR], 0.53; 95% CI, 0.30-0.95; adjusted P = .03). All the biomarkers stratified by HPV status showed significant associations with survival. Patients with HPV-positive, low-expression pRb esophageal tumors were associated with a significantly improved disease-free survival compared with the HPV-negative, high-expression Rb tumors (HR, 0.33; 95% CI, 0.12-0.93; adjusted P = .04). Similarly, HPV-positive, low-expression CD1 was associated with a significantly favorable disease-free survival (HR, 0.26; 95% CI, 0.09-0.76; adjusted P = .01), as was HPV-positive, high-expression MCM2 (HR, 0.27; 95% CI, 0.09-0.78; adjusted P = .02). In regard to overall survival, HPV was significantly associated only with low CD1 (HR, 0.38; 95% CI, 0.15-0.94; adjusted P = .04). This study's findings suggest that low expression of CD1 appears to be an independent prognostic marker in Barrett HGD and EAC. Human papillomavirus positivity in combination with pRb, CD1, MCM2, and Ki-67 was associated with a survival benefit in esophageal tumors. These findings suggest the possibility of personalization of therapy for Barrett HGD and EAC based on viral status.

Abstract WP20: Intra-Arterial Chemotherapy for Retinoblastoma in Infants<10 kg: 74 Treated Eyes With 222 IAC Sessions

Background: Intra-arterial chemotherapy (IAC) for retinoblastoma (Rb) has dramatically altered the natural history of the disease. The spectacular outcomes associated with a high safety profile have pushed the envelope to offer treatment for patients < 10 kg of weight. Objective: We aim to share our findings and experience in a large series of IAC infusions performed in infants < 10 kg. Methods: A retrospective chart review was performed for patients diagnosed with retinoblastoma and managed with IAC as either primary or secondary treatment. Results: There were 207 Rb tumors of 207 eyes in 197 consecutive patients. Of these, patient weight was 10 kg in 69 (35.7%) and >10 kg in 133 (67.5%) patients. Of the 69 patients weighing < 10 kg, 5 patients had bilateral Rb. Thus, a total of 74 eyes of 69 patients weighing < 10 kg were compared to 133 eyes of 133 patients weighing > 10 kg. Comparison ( < 10 kg vs. >10 kg) revealed the total number of IAC cycles was 222 vs. 436. Periprocedural complications occurred in 2 (0.9%) vs. 2 (0.45%) infusions ( p =0.49). Aborted procedure occurred in 12 (5.4%) vs. 7 (1.6%) infusions ( p =0.005). Enucleation following IAC was required in 14 (18.9) vs. 44 (33%) eyes ( p =0.029). On multivariate analysis, weight < 10 kg was not an independent predictor of complications, procedure failure, or eye enucleation. Conclusions: Our results speak for the safety and efficacy of IAC in patients < 10 kg.

The clinical significance of distal spread differs according to the primary tumor location in rectal cancer.

Treatment strategies of rectal cancer differ between tumors located above (RS/Ra) and below (Rb) the peritoneal reflection. Based on the extent of distal spread (DS), the Japanese Society for Cancer of Colon and Rectum proposed an optimal distal margin in RS/Ra and Rb tumors. In this study, we investigated the clinical significance of DS between RS/Ra and Rb tumors. We analyzed 287 stage I-III rectal cancer patients who underwent curative intent resection without preoperative therapy. DS and other pathological factors were evaluated using whole-mount sections. To investigate the clinical significance of DS in RS/Ra and Rb tumors, clinicopathological variables, including DS, were analyzed for the survival outcome according to the tumor group. DS was detected in 20 out of 185 (11%) patients with RS/Ra tumors and 8 out of 102 (8%) patients with Rb tumors. DS was not significantly associated with the overall survival (OS) or relapse-free survival (RFS) in RS/Ra tumors, but was an independent prognostic factor for the OS and RFS in Rb tumors (P = 0.002 and 0.007, respectively). The clinical significance of DS differs between RS/Ra and Rb tumors. DS is associated with a worse survival in Rb tumors, but not in RS/Ra tumors.

Gene expression analysis of retinoblastoma tissues with clinico-histopathologic correlation

Purpose: Retinoblastoma (Rb) is the most common intraocular malignant tumor, which is not only unique but also has unraveled many novel aspects of tumor-suppressor genes. Genetic mutations of Rb, loss of phosphorylation, and many other factors resulted in uncontrolled cell division of the retinal cells resulting in tumor progression. In this study, we have analyzed the gene expression patterns of unilateral tumors (n = 11) in comparison to the normal-appearing retina (n = 2) from Rb patients who underwent enucleation for advanced Rb. With recent advances in the knowledge of the role of stem cells in these tumors, it is important to evaluate and understand the self-renewal signaling involved in these tumors. Here, in this study, we particularly aimed at evaluating the aberrant self-renewal signaling pathways in human Rb tumors and genes which show differential expression in cases with and without histologic risk factors (HRF). Materials and Methods: Freshly unfixed eyeballs (n = 11) were obtained. Normal-appearing retinas were pooled together (n = 2) and used as a control for microarray experiments. Total RNA was isolated from tumors and control tissues, and expression of genes was evaluated by hybridizing to expression arrays. Using real-time polymerase chain reaction (PCR), the results, thus, obtained were validated (for expression of N-Myc, HMGA2, LIN-28b, and Activin receptor 1C [ACVR1C]) in tissues compared to two control retinas latter obtained from enucleated Rb eyeballs without tumor. Furthermore, immunohistochemistry (IHC) was done on retrospective (n = 19) cases to confirm the expression of ACVR1C. Results: In Rb tumors, 5593 genes were upregulated and 4864 genes were downregulated (P ≤ 0.05 and fold change ≥1.5 folds). Changes in N-Myc, HMGA2, LIN28b, and ACVR1C expression detected by microarray were validated by real-time PCR. The analysis shows significant up-regulation of HMGA2 and its downstream regulator LIN-28b, which is involved in self-renewal pathway of fetal neural stem cells. ACVR1C is one of the markers, which shows differential expression between histological subtypes of tumors as evident in IHC. CBLB (P ≤ 0.05) and MAPK 8 (P ≤ 0.05) were shown to be highly upregulated in tumors without HRF compared to cases with HRF. Conclusions: This study showed up-regulation of genes involved in neural stem cell self-renewal and marginally in notch signaling. While other stem cell pathways such as Wnt and sonic hedgehog (SHH) pathways were upregulated in these tumors. Targeting these self-renewal pathways would aid in eliminating the resistant cells in this tumor and thus may help in treating the recurrence. Genes such as CBLB, MAPK 8, and ACVR1C can be used as potential biomarkers in this tumor to prognosticate cases with or without HRFs and differentiation of the tumors.

Retinoblastoma and Neuroblastoma Predisposition and Surveillance.

Retinoblastoma (RB) is the most common intraocular malignancy in childhood. Approximately 40% of retinoblastomas are hereditary and due to germline mutations in the RB1 gene. Children with hereditary RB are also at risk for developing a midline intracranial tumor, most commonly pineoblastoma. We recommend intensive ocular screening for patients with germline RB1 mutations for retinoblastoma as well as neuroimaging for pineoblastoma surveillance. There is an approximately 20% risk of developing second primary cancers among individuals with hereditary RB, higher among those who received radiotherapy for their primary RB tumors. However, there is not yet a clear consensus on what, if any, screening protocol would be most appropriate and effective. Neuroblastoma (NB), an embryonal tumor of the sympathetic nervous system, accounts for 15% of pediatric cancer deaths. Prior studies suggest that about 2% of patients with NB have an underlying genetic predisposition that may have contributed to the development of NB. Germline mutations in ALK and PHOX2B account for most familial NB cases. However, other cancer predisposition syndromes, such as Li-Fraumeni syndrome, RASopathies, and others, may be associated with an increased risk for NB. No established protocols for NB surveillance currently exist. Here, we describe consensus recommendations on hereditary RB and NB from the AACR Childhood Cancer Predisposition Workshop. Clin Cancer Res; 23(13); e98-e106. ©2017 AACRSee all articles in the online-only CCR Pediatric Oncology Series.

Epidemiological Characteristics of Retinoblastoma in Children Attending Almouassat University Hospital, Damascus, Syria, 2012-2016

Retinoblastoma (Rb) is a malignant tumor that originates from the developing retina. Diagnosis is based on clinical signs and symptoms and usually children under the age of five years are affected. Early diagnosis and treatment of Rb and non-ocular tumors can reduce morbidity and increase longevity. Treatment in the early stages may allow a good prognosis and salvage of visual function. The aim of this study is to present descriptive epidemiological aspects of retinoblastomas in children seen at Almouassat University Hospital (AUH) in Damascus, Syria from 1 January 2012 to 31 October 2016In this retrospective, observational hospital survey, medical records of 37 retinoblastoma cases were reviewed. The male/female (M/F) ratio was 1.6. The most frequent presenting sign was leukocoria (56.7%) and 81% of cases were diagnosed between the ages of 4 months and 3 years. More than 73% of cases were diagnosed early at stages I and II.

Systematic review of the current status of programs and general knowledge of diagnosis and management of retinoblastoma

BackgroundThis systematic review aims to report the current knowledge of retinoblastoma (Rb) and its implications in Mexico. We analyzed clinical and demographic data of patients with Rb at select hospitals with Rb programs or that treat and refer patients with Rb, and identified the gaps in practice. We propose solutions to improve diagnosis, provide adequate treatment, and improve patient uptake. MethodsA general review was conducted on PubMed of peer-reviewed literature on Rb in Mexico. Ophthalmology Department Heads or Directors of Rb programs at seven hospitals in Mexico were contacted for data available on their patients with Rb. ResultsFive hospitals provided clinical data on 777 patients with Rb in a period spanning 2000-2015. Of the 122 patients with treatment, 83.4% underwent enucleation. From 33 to 45.3% of Rb tumors in Mexico reach an advanced intraocular stage of development. Knowledge of the disease is limited, despite the fact that the Mexican Retinoblastoma Group has elaborated Rb treatment guidelines and is developing a national Rb registry. Especially in the Southern states, prevalence and outcomes are comparable to African and Asian countries, and only few patients are referred to national treatment centers. Only three institutions have comprehensive Rb programs. ConclusionsThere is an immediate need in Mexico to expand primary care providers’ knowledge of Rb and to expand and upgrade current Rb programs to meet the needs of the population adequately. Diagnosis and care of Rb patients in Mexico can also be improved by the establishment of a national Rb registry and a national early detection program, and by increased use of the national treatment protocol.

Targeting HSP90/Survivin using a cell permeable structure based peptido-mimetic shepherdin in retinoblastoma

BackgroundRetinoblastoma (RB) is a childhood retinal malignancy. Effective therapeutic strategies are still being investigated in RB disease management. Here, the anti-cancer effect of shepherdin, a peptido-mimetic inhibiting heat shock protein (HSP90)-Survivin interaction has been analyzed. MethodsWe analyzed HSP (HSP70/90) and Survivin protein expressions by immunohistochemistry (29 archival tumors), qRT-PCR, FACS and Western analysis (10 un-fixed RB tumors). We also analyzed cellular cytotoxicity and anti-proliferative effect in peptide treated RB cells (Y79, Weri Rb1) and MIO-M1 cells. ResultsHeterogeneous expressions of HSP70/90 and Survivin with a significant association between HSP70 and HSP90 (r2 = 0.59, p = 0.001) was observed. In RB cells, anti-tumor effects were detected with 0.42 μg/ml of shepherdin at 4 h s of serum starvation. Decreased Survivin, Bcl2, MMP-2 activity with increased Bax, Bim, and Caspase-9 protein expressions were noticed. No significant changes were observed in shepherdin treated non-neoplastic MIO-M1, nor in scramble-peptide treated RB cells. ConclusionThe presence of HSPs (HSP70/90) and Survivin reveals multiple cellular mechanisms adopted by RB cells during cancer progression. Serum starvation induced HSP90 whose interactions with Survivin were specifically inhibited by shepherdin. The associated molecular shuffling has been reported. These findings strongly implicate the potential of targeting HSP90-Survivin interaction as an adjuvant therapy in RB management.

Targeting Survivin Enhances Chemosensitivity in Retinoblastoma Cells and Orthotopic Tumors.

Treatments for retinoblastoma (Rb) vary depending on the size and location of the intraocular lesions and include chemotherapy and radiation therapy. We examined whether agents used to treat Rb induce a pro-survival phenotype associated with increased expression of survivin, a member of the inhibitor of apoptosis family of proteins. We document that exposure to carboplatin, topotecan or radiation resulted in elevated expression of survivin in two human Rb cell lines but not in normal retinal pigmented epithelial (RPE) cells. Cellular levels of survivin were attenuated in Rb cells exposed to an imidazolium-based survivin suppressant, Sepantronium bromide (YM155). Protein expression patterns of survivin in RPE cells were not altered following treatment protocols involving exposure to YM155. Including YM155 with chemotherapy or radiation increased levels of apoptosis in Rb cells but not in RPE cells. Intraocular luciferase expressing Rb tumors were generated from the Rb cell lines and used to evaluate the effects of carboplatin and YM155 on in-vivo survivin expression and tumor growth. Carboplatin induced expression of survivin while carboplatin combined with YM155 reduced survivin expression in tumor bearing eyes. The combination protocol was also most effective in reducing the rate of tumor regrowth. These results indicate that targeted inhibition of the anti-apoptotic protein survivin provides a therapeutic advantage for Rb cells and tumors treated with chemotherapy.