Retinoblastoma Research Articles

Simultaneous Copy Number Alteration and Single-Nucleotide Variation Analysis in Matched Aqueous Humor and Tumor Samples in Children with Retinoblastoma.

Retinoblastoma (RB) is a childhood cancer that forms in the developing retina of young children; this tumor cannot be biopsied due to the risk of provoking extraocular tumor spread, which dramatically alters the treatment and survival of the patient. Recently, aqueous humor (AH), the clear fluid in the anterior chamber of the eye, has been developed as an organ-specific liquid biopsy for investigation of in vivo tumor-derived information found in the cell-free DNA (cfDNA) of the biofluid. However, identifying somatic genomic alterations, including both somatic copy number alterations (SCNAs) and single nucleotide variations (SNVs) of the RB1 gene, typically requires either: (1) two distinct experimental protocols-low-pass whole genome sequencing for SCNAs and targeted sequencing for SNVs-or (2) expensive deep whole genome or exome sequencing. To save time and cost, we applied a one-step targeted sequencing method to identify both SCNAs and RB1 SNVs in children with RB. High concordance (median = 96.2%) was observed in comparing SCNA calls derived from targeted sequencing to the traditional low-pass whole genome sequencing method. We further applied this method to investigate the degree of concordance of genomic alterations between paired tumor and AH samples from 11 RB eyes. We found 11/11 AH samples (100%) had SCNAs, and 10 of them (90.1%) with recurrent RB-SCNAs, while only nine out of 11 tumor samples (81.8%) had positive RB-SCNA signatures in both low-pass and targeted methods. Eight out of the nine (88.9%) detected SNVs were shared between AH and tumor samples. Ultimately, 11/11 cases have somatic alterations identified, including nine RB1 SNVs and 10 recurrent RB-SCNAs with four focal RB1 deletions and one MYCN gain. The results presented show the feasibility of utilizing one sequencing approach to obtain SCNA and targeted SNV data to capture a broad genomic scope of RB disease, which may ultimately expedite clinical intervention and be less expensive than other methods.

Clinical characteristics, treatment and prognosis of infants with retinoblastoma: a multicenter, 10-year retrospective analysis

BackgroundTo summarize the characteristics and treatment, and analyze the prognosis of large number of infants with retinoblastoma (RB) in China through a multicenter, 10-year retrospective analysis.MethodsThe data of RB infants were collected from multiple centers. The characteristics and survival prognosis were analyzed. The overall survival (OS) rate was estimated by the Kaplan–Meier method. Multivariate Cox survival analysis was to evaluate the independent risk factors affecting the prognosis of RB infants.ResultsA total of 373 RB infants (202 boys and 171 girls) were included, the median age was 6.22 months (10 days to 11.93 months). The median follow-up time of RB infants was 18.4 (1.02–122.81 months). After excluding the lost to follow-up cases, the OS rate was 97.7% (345/353). Kaplan–Meier survival analysis indicated that 9 cases died and the median survival time was not reached. Univariate analysis of prognostic factors revealed eye affected, presenting signs, left eye stage and recurrence to be poor prognostic factors for OS rate in RB infants (all P < 0.05). Multivariate Cox regression analyses for OS showed recurrence (HR = 1.376, 95% CI: 0.878–2.156, P = 0.048) was an independent factor for prognosis of infants with RB. The median survival time of infants underwent chemotherapy + intra-arterial chemotherapy (IAC) + enucleation + vitrectomy was the longest than other treatments (n = 9, 47.64 months, OS = 100%, all P < 0.05). There was a history of RB in 17 infants' lineal relatives. Kaplan-merier survival analysis indicated 1 case died and the median survival time was not reached.ConclusionRecurrence is an independent factor for prognosis of RB infants, which still needs attention after treatment. Early screening, comprehensive treatments and follow-up of patients may lead to improvements of prognosis of RB infants.

The association between maternal nutrient intake during pregnancy and the risk of sporadic unilateral retinoblastoma among offspring

Previous studies have associated maternal diet during pregnancy with the development of sporadic unilateral retinoblastoma (RB), but few studies have focused on the role of individual nutrients. The aim of this study is to investigate the association between maternal nutrient intake during pregnancy and the development of sporadic unilateral RB in the offspring.A modified food frequency questionnaire, with additional questions on supplement use, was completed via a phone interview. Cases were recruited from hospitals and controls were comprised of friends and relatives of the patient without a history of cancer. Overall, 168 sporadic unilateral RB cases and 145 controls were included in case-control study. We performed logistic regression to estimate odds ratios (ORs) and 95 % confidence intervals (CI), adjusting for child’s age, child’s sex, parental race/ethnicity, maternal education, total calorie intake during pregnancy, maternal age at birth, maternal smoking during pregnancy, pre-pregnancy body mass index, maternal weight gain during pregnancy, paternal age at birth, and maternal multivitamin use in the year before pregnancy.In the adjusted model, the interquartile (IQR) increase in vitamin A intake, which was measured in retinol activity equivalent (RAE; OR: 0.64, 95 % CI: 0.46–0.90), and vitamin D intake (OR: 0.62, 95 % CI: 0.42–0.91) significantly reduced the risk of sporadic unilateral RB.These findings suggest that a higher intake of vitamins A and D can be a protective factor for sporadic unilateral RB. Further analyses in consideration of multi-exposures such as parental occupational exposures are warranted to discover the complex etiology of sporadic unilateral RB. In addition, the role of nutritional epigenetics for how maternal nutrient intake influences the risk of sporadic unilateral RB in the offspring still needs to be explored.

NSUN2-mediated m5 C RNA methylation dictates retinoblastoma progression through promoting PFAS mRNA stability and expression.

The precise temporal and spatial regulation of N5 -methylcytosine (m5 C) RNA modification plays essential roles in RNA metabolism, and is necessary for the maintenance of epigenome homeostasis. Howbeit, the mechanism underlying the m5 C modification in carcinogenesis remains to be fully addressed. Global and mRNA m5 C levels were determined by mRNA isolation and anti-m5 C dot blot in both retinoblastoma (RB) cells and clinical samples. Orthotopic intraocular xenografts were established to examine the oncogenic behaviours of RB. Genome-wide multiomics analyses were performed to identify the functional target of NSUN2, including proteomic analysis, transcriptome screening and m5 C-methylated RNA immunoprecipitation sequencing (m5 C-meRIP-seq). Organoid-based single-cell analysis and gene-correlation analysis were performed to verify the NSUN2/ALYREF/m5 C-PFAS oncogenic cascade. Herein, we report that NSUN2-mediated m5 C RNA methylation fuels purine biosynthesis during the oncogenic progression of RB. First, we discovered that global and mRNA m5 C levels were significantly enriched in RBs compared to normal retinas. In addition, tumour-specific NSUN2 expression was noted in RB samples and cell lines. Therapeutically, targeted correction of NSUN2 exhibited efficient therapeutic efficacy in RB both in vitro and in vivo. Through multiomics analyses, we subsequently identified phosphoribosylformylglycinamidine synthase (PFAS), a vital enzyme in purine biosynthesis, as a downstream candidate target of NSUN2. The reintroduction of PFAS largely reversed the inhibitory phenotypes in NSUN2-deficient RB cells, indicating that PFAS was a functional downstream target of NSUN2. Mechanistically, we found that the m5 C reader protein ALYREF was responsible for the recognition of the m5 C modification of PFAS, increasing its expression by enhancing its RNA stability. Conclusively, we initially demonstrated that NSUN2 is necessary for oncogenic gene activation in RB, expanding the current understanding of dynamic m5 C function during tumour progression. As the NSUN2/ALYREF/m5 C-PFAS oncogenic cascade is an important RB trigger, our study suggests that a targeted m5 C reprogramming therapeutic strategy may be a novel and efficient anti-tumour therapy approach.

Mental Wellbeing among Children with Cancer during COVID-19 Pandemic in Indonesia: A Cross-sectional Study

Abstract Introduction Coronavirus disease 2019 (COVID-19) has affected both physical and mental aspect of people worldwide, especially the high-risk group such as pediatric cancer patients. Children with cancer were considered both clinically and mentally vulnerable during this pandemic. They were also affected by the self-isolation, quarantine, and social distancing policy taken as a respond to public threat. Objectives To evaluate the impact of social distancing and health protocol during COVID-19 on the mental health profile of children with cancer in Indonesia. Methods A cross-sectional study evaluating the mental health of children with cancer during COVID-19 pandemic was conducted in Cipto Mangunkusumo Hospital, Jakarta, Indonesia from June to September 2020. An online questionnaire was used to collect demographics of parents and children, children's Strength and Difficulties Questionnaire (SDQ) score, and parents' Self-Reporting Questionnaire (SRQ). SDQ score consists of five subscales, including the emotional symptoms, conduct problems, hyperactivity, peer relationships problems and prosocial behavior. Cancer types were grouped into retinoblastoma, nonretinoblastoma (other solid tumors), and leukemia. Results There were 156 valid responses, consisting of 42 patients with retinoblastoma, 34 patients with nonretinoblastoma (other solid tumors), and 80 patients with leukemia. Pandemic-related lifestyle changes did not significantly impact emotional or behavioral problems. Children with normal total SDQ (odds ratio [OR]: 473, p = 0.001) and emotional scores (OR: 3.19, p = 0.07) had parents with normal SRQ scores (&lt;6). Leukemia patients with shorter diagnosis period had worse hyperactivity score (p = 0.01). On the contrary, leukemia inpatients had better prosocial scores than outpatients (p = 0.03). More bilateral retinoblastoma patients (p = 0.04) with longer duration of cancer diagnosis (p = 0.03) faced peer problems. Conclusions Our study revealed that lifestyle changes during early COVID-19 pandemic were not major factors impacting emotional and behavioral problems in children with cancer. However, disease-related factors pose great challenges; thus, a holistic mental health support system should be available to both children and parents.

Evaluation of ultrasound examination informativity in diagnosing retinoblastoma

The aim of this work is to evaluate the informativity of the ultrasound (US) in detecting retinoblastoma (RB) and the local invasion of the tumor in children using modern multi-purpose ultrasound scanners.Materials and methods. This study included 108 patients (216 eyes) examined for suspected RB. RB was diagnosed in 91 patients, 60 children had unilateral tumor, 31 – bilateral tumor (122 eyes). In the remaining 17 children (20 eyes damaged), different non-tumor pathology of the eye was revealed. Among 122 eyes affected by RB, 51 were removed with subsequent histological examination. 27 eyes were removed before treatment, 24 – after chemotherapy.Results. In our study the informativity of ultrasound in detecting RB are: sensitivity – 98.4 %, specificity – 96.8 %, accuracy – 97.7 %. Sensitivity, specificity and accuracy in assessing tumor invasion to the anterior segment of the eye are 36.4 %, 95.0 % and 82.4 % respectively, to the vitreous body – 97.7 %, 100 % and 97.9 %, to the optic nerve – 54.5 %, 57.1 % and 54.9 %.Conclusion. US examination using linear transducers of 9–18 MHz is highly informative in detecting RB, however, some indicators of the effectiveness in assessing local invasion are not high enough, due to the technical possibilities of the method. One possible way to improve the informativity – to use deep sedation during US examination.

Algorithm for evaluating ophthalmic artery pseudo-occlusion during intra-arterial chemotherapy for retinoblastoma.

Intra-arterial chemotherapy infusion for retinoblastoma is typically performed via selective catheterization of the ophthalmic artery. Anastomoses between the external carotid and the ophthalmic arteries have also been utilized when the ophthalmic artery cannot be catheterized directly. However, these are not present in every patient. A 10-month-old boy presented with bilateral retinoblastoma and underwent one round of intra-arterial chemotherapy (IAC) via direct catheterization of the ophthalmic arteries. Combined with adjuvant laser therapy, they experienced symptomatic improvement and tumour regression. However, during subsequent treatment sessions both ophthalmic arteries did not have anterograde flow and attempts to catheterize their origin were unsuccessful. Unfortunately, no targetable anastomoses between the external carotid and ophthalmic arteries were identified for drug delivery. Due to the patient's anatomy, balloon occlusion of the ECA was felt to be unsafe. As a salvage technique, a balloon was inflated in the left internal carotid artery (ICA) distal to the ophthalmic take-off to redirect flow into the ophthalmic. Repeat angiography with the distal ICA occluded showed improved flow into the ipsilateral ophthalmic artery. IAC was then successfully delivered through the left ICA. This case illustrates the importance of utilizing creative endovascular techniques for targeted intra-arterial drug delivery when other conventional measures fail as these patients often have limited, and potentially higher risk, therapeutic alternatives.

The novel polyfluoroalkyl benzenesulfonate OBS exposure induces cell cycle arrest and senescence of rat pituitary cell GH3 via the p53/p21/RB pathway

Sodium p-perfluorous nonenoxybenzene sulfonate (OBS), an economical alternative to perfluorooctane sulfonate (PFOS) in multiple industrial fields, is widely detected in the environment. The toxicity of OBS has received increasing attention. Pituitary cells are components of the endocrine system and act as vital regulators of homeostatic endocrine balance. However, the effects of OBS on pituitary cells remain unknown. The present study explores the effects of OBS (0.5, 5, and 50 μM) on GH3 rat pituitary cells after treatment for 24, 48, and 72 h. We found that OBS significantly inhibited cell proliferation in GH3 cells with remarkable senescent phenotypes, including enhanced SA-β-gal activity and expression of senescence-associated secretory phenotype (SASP)-related genes, cell cycle arrest, and upregulation of the senescence-related proteins γ-H2A.X and Bcl-2. OBS caused significant cell cycle arrest of GH3 cells at the G1-phase and concomitantly downregulated the expression of some key proteins for the G1/S transition, including cyclin D1 and cyclin E1. Consistently, the phosphorylation of retinoblastoma (RB), which plays a central role in regulating the cell cycle, was prominently reduced after OBS exposure. Furthermore, OBS notably activated the p53-p21 signalling pathway in GH3 cells, as evidenced by increased p53 and p21 expressions, enhanced p53 phosphorylation, and augmented p53 nuclear import. To our knowledge, this study is the first to reveal that OBS triggers senescence in pituitary cells via the p53-p21-RB signalling pathway. Our study demonstrates a novel toxic effect of OBS in vitro, and provides new perspectives for understanding the potential toxicity of OBS.

MiR-4529-3p Promotes the Progression of Retinoblastoma by Inhibiting RB1 Expression and Activating the ERK Signaling Pathway.

Retinoblastoma (RB) is a malignant ocular cancer that affects children. Several microRNAs (miRNAs) have been implicated in RB regulation. The present study aimed to investigate the role of miR-4529-3p in RB pathogenesis. Scratch, Transwell, and Cell Counting Kit (CCK)-8 assays were conducted to assess the migratory, invasive, and proliferative abilities of RB cells. The expression levels of miR-4529-3p, RB1, and ERK pathway-related proteins were analyzed using western blotting and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Target relationships were verified using dual-luciferase reporter experiments. A murine RB model was developed to analyze the effects of miR-4529-3p on RB tumor growth in vivo. Our experiments revealed high levels of miR-4529-3p and low levels of RB1 in RB tissues. Functional analyses revealed that the migratory, invasive, and proliferative abilities of RB cells were repressed by miR-4529-3p inhibition. Similarly, p-ERK 1/2 protein levels were suppressed by miR-4529-3p inhibition. Furthermore, downregulation of miR-4529-3p limited tumor growth in vivo. Mechanistically, miR-4259-3p targets RB1. Interestingly, RB1 silencing abrogated the alleviative effects of miR-4529-3p downregulation in RB cells. MiR-4529-3p promotes RB progression by inhibiting RB1 and activating the ERK pathway. This evidence suggests that the miR-4529-3p/RB1 regulatory axis may be a prospective target for RB treatment in clinical settings.

Primary Subretinal Seeding in Retinoblastoma: Clinical Presentation and Treatment Outcomes

Introduction: The aim of this study was to describe the clinical features and treatment outcomes of primary subretinal seeding (SRS) in patients with intraocular retinoblastoma (RB). Methods: Descriptive analysis of primary SRS in 47 patients (50 eyes) with RB was performed. Results: Mean age was 19 months (range, 2–72 months), and 55% (n = 26) of the subjects were male. At presentation, the SRS involved two or more quadrants in 88% of eyes. Most seeds appeared yellowish gray (66%) and round to oval in shape (48%). Two-thirds of SRS were seen posterior to the equator and within 5 mm from the main tumor. Associated features included subretinal fluid in 50 eyes (100%), total retinal detachment in 28 eyes (56%), and vitreous seeds in 20 eyes (40%). Treatment included intravenous chemotherapy (IVC) (n = 47; 94%), enucleation (n = 2; 4%), and intra-arterial chemotherapy (n = 1; 2%). SRS treatment included adjunct use of focal transpupillary thermotherapy and/or cryotherapy (n = 20; 40%). Retinal tumor control was achieved in 36 eyes (76%) with 32 eyes (78%) showing a type 3 regression pattern, while SRS completely regressed in 24 (48%) eyes, partially in 15 (30%) and worsened in 2 (4%) eyes. Over a mean follow-up of 30 months (range, 3–68 months), SRS recurrence was noted in 12 eyes (29%), globe salvage was achieved in 39 eyes (78%), and 1 (4%) patient died of presumed metastasis. Conclusion: Primary SRS pose a therapeutic challenge during RB treatment. The SRS responds moderately to systemic IVC, with one-third cases showing SRS recurrence and one-fifth ultimately requiring enucleation.

Abstract 6717: Extracellular vesicles in diagnostic retinoblastoma aqueous humor correlate with disease stage and clinical outcome: a pilot study

Abstract Introduction: Retinoblastoma (RB), a pediatric retinal malignancy, is unique in that it cannot be biopsied, impeding biomarker discovery. Aqueous humor (AH) is an ocular fluid that is an established source of tumor information, serving as a surrogate liquid biopsy. Extracellular vesicles (EVs) are promising biomarker candidates, and were recently established in RB AH. EVs are membrane-enclosed secretory vesicles carrying bioactive molecular information, which can be phenotyped using validated tetraspanin protein markers. Currently, relationships between EVs and RB clinical features are unknown, but establishing such relationships is necessary to determine the utility of EVs as RB biomarkers. Methods: We quantified and phenotyped EVs in 37 AH samples from 18 RB eyes with varying International Intraocular Retinoblastoma Classification (IIRC) stages and explored clinical correlations. Samples were collected from 10 eyes at diagnosis (DX) and 27 eyes during treatment (Tx). By outcome, 6 DX eyes were enucleated and 4 were salvaged. DX samples were collected from one A, one B, six D and two E eyes by IIRC group. 10μL of unprocessed AH underwent Single Particle-Interferometric Reflectance Imaging Sensor (SP-IRIS) (Exoview R100) analysis for fluorescent-based particle count and immunophenotyping of tetraspanin expression (CD63/81/9). Counts were converted to percentages. Statistics were done with Mann-Whitney U, ANOVA, and Tukey’s tests. Results: Samples from DX eyes (n=10) contained a higher number of EVs than samples from Tx eyes (n=27) (1.68 x 107 ± 4.28 x 107 per mL vs. 2.10x 106 ± 1.33 x 106 per mL) by SP-IRIS analysis. By percentage, DX samples were enriched with CD63/81+ EVs (P&amp;lt;0.001) while Tx samples had more homogenous mono-CD63+ dominant EV populations (P=0.007). Enrichment of CD63/81+ EVs was significantly higher in enucleated AH (n=6) than salvaged AH (n=4) when compared by count (P=0.038) and marginally higher when compared by percentage (P=0.067). The CD9/81+ EV population percentage was significant in salvaged eyes (P=0.01). By IIRC, CD63/81+ EVs were most abundant in Group E eyes (n= 2) when compared to Group D eyes (n=6) by count (P&amp;lt;0.001), and when compared to Group A+B eyes (n=2) by count (P=0.01) and percentage (P=0.019). Group A+B eyes had a larger percentage of CD9/81+ EVs than did Group E eyes (P=0.043). Conclusions: EV quantity in RB AH decreases with treatment, and phenotypic expression profiles vary by treatment status and clinical outcome. TheCD63/81+ EV subpopulation is higher in eyes with advanced Group E disease and those requiring enucleation, while the CD9/81+ subpopulation is higher in eyes with less advanced Group A+B disease and those salvaged with treatment. Our data suggests that EV phenotypes correlate with RB clinical features, and further research into these subpopulations offers the prospect of establishing critical RB biomarkers. Citation Format: Sarah Pike, Chen-Ching Peng, Paolo Neviani, Jesse L. Berry, Liya Xu. Extracellular vesicles in diagnostic retinoblastoma aqueous humor correlate with disease stage and clinical outcome: a pilot study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6717.

The functional role of circular RNAs in the pathogenesis of retinoblastoma: a new potential biomarker and therapeutic target?

Retinoblastoma (RB) is a common cancer in infants and children. It is a curable disease; however, a delayed diagnosis or treatment makes the treatment difficult. Genetic mutations have a central role in the pathogenesis of RB. Genetic materials such as RNAs (coding and non-coding RNAs) are also involved in the progression of the tumor. Circular RNA (circRNA) is the most recently identified RNA and is involved in regulating gene expression mainly through "microRNA sponges". The dysregulation of circRNAs has been observed in several diseases and tumors. Also, various studies have shown that circRNAs expression is changed in RB tissues. Due to their role in the pathogenesis of the disease, circRNAs might be helpful as a diagnostic or prognostic biomarker in patients with RB. In addition, circRNAs could be a suitable therapeutic target to treat RB in a targeted therapy approach.

Novel point mutation and intronic mutations of &lt;em&gt;RB1&lt;/em&gt; gene in retinoblastoma patients in Indonesia

BACKGROUND Retinoblastoma (RB) is an inherited disorder caused by the RB1 gene mutation in retinal cells or germline mutation. Identifying the specific mutation is crucial for prognosis, inheritance risk assessment, and treatment planning. This study aimed to identify the germline mutation in the RB1 gene in patients with RB and their parents from the eastern part of Indonesia.&#x0D; METHODS This observational analytic study recruited patients with RB and their parents between 2016 and 2018 at Dr. Wahidin Sudirohusodo Hospital, Makassar, Indonesia. The normal control subjects were children from the outpatient clinic at the Department of Ophthalmology, Universitas Hasanuddin Hospital. Ophthalmic examinations and peripheral blood tests were performed in RB patients, their parents, and control subjects. Genomic DNA was isolated from blood leukocytes and amplified using conventional PCR. Hotspot exons 8, 10, 14, 17, and 22 were screened for mutations using the Sanger method.&#x0D; RESULTS There were 21 patients with RB (16 unilateral and 5 bilateral) and 14 normal subjects. Of the 184 variations detected in RB patients, 164 were also found in normal subjects. 19 intronic mutations in introns 10, 16, 17, and 21, and 1 novel missense mutation in exon 17 were identified. Parental testing revealed 8 substitutions in exon 17 and 5 intronic mutations in introns 16 and 17 of the parents. None of the variations in exons were passed to their children.&#x0D; CONCLUSIONS This study found a novel missense mutation in exon 17 of the RB1 gene.

Follow-up of retinoblastoma using RetCam fluorescein angiography and correlation with clinical findings.

To report RetCam fluorescein angiographic (FA) changes and correlation with clinical findings in the follow-up of retinoblastoma (RB) after frontline intravenous chemotherapy and other treatments. Patients having RB who underwent post-treatment RetCam fundus photography and FA under general anesthesia between February 2020 and February 2022 were retrospectively analyzed. 78 eyes of 70 patients with RB were included. In 55 (70.5%) eyes with type 1, 2 or 3 regression patterns, the main tumor started to show hyperfluorescence in arterial phase in 24 eyes (43.6%), in early venous phase in 24 (43.6%) eyes, and in late venous phase in 7 (12.7%) eyes. Of thirty-six (46.2%) eyes with chorioretinal scars developing after focal treatments (cryotherapy and transpupillary thermotherapy), window defects and visible choroidal vessels were found in all eyes, scleral staining in 10 (27.8%), and gliosis on scar tissue in 8 (22.2%). Vitreous seeds showed hyperfluorescence if they were calcified (6 eyes, 7.7%) and hypofluorescence if non-calcified (11 eyes, 14.1%). Retrohyaloid seeds (11 eyes, 14.1%) were hypo/isofluorescent while subretinal seeds (6 eyes, 7.7%) were hyperfluorescent. Leakage from peripheral retinal vessels was detected in 14 (17.9%) eyes and non-perfusion in 6 (7.7%) eyes. RetCam wide-angle FA is useful to evaluate the tumor and associated vascular and retinal changes after treatment in RB. Regressed tumors demonstrate later fluorescein uptake in venous phases. Fluorescein angiographic changes in chorioretinal scars include window defects, visibility of choroidal vessels, scleral staining, and leakage from vessels. Retinal vascular leakage and peripheral non-perfusion can be seen in eyes with regressed stable tumors.

Correlating somatic copy number alteration in aqueous humour cfDNA with chemotherapy history, eye salvage and pathological features in retinoblastoma

BackgroundThis study determined to probe the potential association between somatic copy number alteration (SCNA) in retinoblastoma (RB) aqueous humour (AH) and pathological high-risk factors, clinical features and previous chemotherapy history.MethodsSingle-centre...

Anisometric Cell/Dysplastic Lipomas in a Retinoblastoma Survivor: Report of a Case with Review of the Literature.

Different authors have recently described a subtype of lipoma characterized by variation of adipocyte size, single cell fat necrosis, and a subset with minimal to mild nuclear atypia, and termed these as anisometric cell/dysplastic lipoma (AC/DL). These lipomas follow a benign course and rarely recur. In 3 examples, AC/DL has occurred in patients with childhood retinoblastoma (RB). We report another such example where multiple AC/DL occurred in the neck and back of a 30-year-old male who had germline RB1 gene deletion and bilateral RB in infancy. On excision, all tumors histologically showed similar morphology of adipocyte anisometry, focal single cell necrosis with surrounding binucleated or multinucleated histiocytes, hyperchromatic and minimally atypical lipocyte nuclei, vacuolated Lockhern change, rare foci of fibromyxoid change, occasional mononuclear cell clusters around capillaries, and loss of RB1 immunostaining. Unequivocal atypical cells, lipoblasts, floret-nucleated or multinucleated giant cells were absent. Molecular analysis of tumor cells showed monoallelic RB1 gene loss without amplification of MDM2 and CDK4 genes. Short-term follow up did not show tumor recurrence. AC/DLs in RB survivors are characterized by multiplicity, unifying histology, and benign course. Their biology appears distinct from ordinary lipomas, spindle cell lipomas, and atypical lipomatous tumors.

Tumor Suppressor Role of INPP4B in Chemoresistant Retinoblastoma.

The chemotherapy of retinoblastoma (RB), a malignant ocular childhood disease, is often limited by the development of resistance against commonly used drugs. We identified inositol polyphosphate 4-phosphatase type II (INPP4B) as a differentially regulated gene in etoposide-resistant RB cell lines, potentially involved in the development of RB resistances. INPP4B is controversially discussed as a tumor suppressor and an oncogenic driver in various cancers, but its role in retinoblastoma in general and chemoresistant RB in particular is yet unknown. In the study presented, we investigated the expression of INPP4B in RB cell lines and patients and analyzed the effect of INPP4B overexpression on etoposide resistant RB cell growth in vitro and in vivo. INPP4B mRNA levels were significantly downregulated in RB cells lines compared to the healthy human retina, with even lower expression levels in etoposide-resistant compared to the sensitive cell lines. Besides, a significant increase in INPP4B expression was observed in chemotherapy-treated RB tumor patient samples compared to untreated tumors. INPP4B overexpression in etoposide-resistant RB cells resulted in a significant reduction in cell viability with reduced growth, proliferation, anchorage-independent growth, and in ovo tumor formation. Caspase-3/7-mediated apoptosis was concomitantly increased, suggesting a tumor suppressive role of INPP4B in chemoresistant RB cells. No changes in AKT signaling were discernible, but p-SGK3 levels increased following INPP4B overexpression, indicating a potential regulation of SGK3 signaling in etoposide-resistant RB cells. RNAseq analysis of INPP4B overexpressing, etoposide-resistant RB cell lines revealed differentially regulated genes involved in cancer progression, mirroring observed in vitro and in vivo effects of INPP4B overexpression and strengthening INPP4B's importance for cell growth control and tumorigenicity.

Non-canonical functions of SNAIL drive context-specific cancer progression

SNAIL is a key transcriptional regulator in embryonic development and cancer. Its effects in physiology and disease are believed to be linked to its role as a master regulator of epithelial-to-mesenchymal transition (EMT). Here, we report EMT-independent oncogenic SNAIL functions in cancer. Using genetic models, we systematically interrogated SNAIL effects in various oncogenic backgrounds and tissue types. SNAIL-related phenotypes displayed remarkable tissue- and genetic context-dependencies, ranging from protective effects as observed in KRAS- or WNT-driven intestinal cancers, to dramatic acceleration of tumorigenesis, as shown in KRAS-induced pancreatic cancer. Unexpectedly, SNAIL-driven oncogenesis was not associated with E-cadherin downregulation or induction of an overt EMT program. Instead, we show that SNAIL induces bypass of senescence and cell cycle progression through p16INK4A-independent inactivation of the Retinoblastoma (RB)-restriction checkpoint. Collectively, our work identifies non-canonical EMT-independent functions of SNAIL and unravel its complex context-dependent role in cancer.

Establishment of patient-derived xenografts of retinoblastoma and choroidal melanoma on the avian chorioallantoic membrane.

To develop a viable in vivo chorioallantoic membrane (CAM) model to study the growth and invasion of patient-derived retinoblastoma (RB) and choroidal melanoma (CM) xenografts (PDXs). The study utilizes primary tumor samples instead of cancer cell lines, which provides a more authentic representation of tumors due to conserved morphology and heterogeneity. Fertilized chicken eggs were procured, windowed, and their CAM layers were dropped. On embryonic development day (EDD) 10, freshly cut patient-derived CM and RB tumors were implanted on the CAM layer and the setup was incubated for 7 days. The tumor-embedded CAM layer was harvested on EDD 17, and the extracted tumor samples were subjected to hematoxylin and eosin staining and immunohistochemical analysis to evaluate the extent of tumor invasion. Significant changes in the vascularity around the RB and CM PDXs were observed, indicating an angiogenic environment. The cross-sectional histological view of the tumor implant site revealed the invasion of both the tumors into the CAM mesoderm. Invasion of CM into CAM mesoderm was visualized in the form of pigmented nodules, and that of RB was indicated by synaptophysin and Ki-67 positivity in Immunohistochemistry (IHC). The CAM xenograft model was successfully able to support the growth of CM and RB PDXs and their invasion in CAM, thus presenting as a feasible alternative to mammalian models for studying tumorigenicity and invasiveness of ocular tumors. Moreover, this model can further be utilized to develop personalized medicine by inoculating patient-specific tumors for preclinical drug screening.

Abstract P3-11-07: Inhibition of FASN as a potential treatment of advanced endocrine therapy-resistant breast cancer

Abstract INTRODUCTION: The past decade has seen significant advancement in increasing survival in estrogen receptor alpha (ERα) positive breast cancer. The use of selective estrogen receptor down-regulators and modulators (SERMs) (e.g. fulvestrant and tamoxifen), mTOR inhibitors (e.g. everolimus), aromatase inhibitors (AIs), and cyclin-dependent kinase inhibitors (e.g. palbociclib, ribociclib, and abemaciclib) have helped to extend overall survival of breast cancer patients. Unfortunately, resistance to endocrine therapy is a common occurrence and all patients will eventually succumb to their disease. Fatty acid synthase (FASN) is a key enzyme in lipid biosynthesis and is overexpressed in more aggressive and therapy-resistant tumors, including breast cancers. FASN inhibitor, TVB-2640, has been evaluated in multiple tumor cell lines and in a phase 1 clinical study, and showed partial responses in 5 patients and multiple patients with prolonged stable disease (≥16 weeks). METHODS: We generated tamoxifen- and fulvestrant-resistant MCF7 cells by long term exposure to tamoxifen (MCF7/TamR cells) and fulvestrant (MCF7/FR cells), and palbociclib-resistant (MCF7/RB1Crispr and ZR75/RB1Crispr) cells were generated through CRISPR/Cas9 knockout of the retinoblastoma (RB) gene. We assessed the impact of TVB-3166 inhibitor (and analog of TVB-2640 with slightly lower molecular weight for in vitro use) on proliferation, viability, cell cycle, and apoptosis in these cells. We evaluated the impact of TVB on proliferation and ERα expression in patient derived explants, and tumor growth in xenografts. RNA sequencing of tamoxifen- and fulvestrant-resistant cells was performed to investigate alterations in gene expression. Subcellular localization of ERα was assessed using subcellular fractionations. Palmitoylation and ubiquitination of ERα were assessed by immunoprecipitation. ERα and p-eIF2α protein levels were analyzed by western blotting after treatment with TVB with or without the addition of palmitate or BAPTA. RESULTS: TVB treatment leads to a marked inhibition of proliferation in tamoxifen-, fulvestrant- and palbociclib-resistant cells compared to the parental cells. RNA sequencing of explants of patients with ERα positive disease showed down regulation of ESR1 related genes and genes involved in invasiveness. RNA sequencing of fulvestrant-resistant cells showed that treatment with TVB results in down regulation of EMT and E2F target genes, cholesterol homeostasis genes and mTORC1 signaling. Additionally, TVB significantly inhibited tumor growth in mice and decreased proliferation of primary tumor explants compared to untreated controls. FASN inhibition significantly reduced ERα levels most prominently in endocrine resistant cells and altered its subcellular localization. Furthermore, we showed that the reduction of ERα expression upon TVB treatment is mediated through the induction of endoplasmic reticulum stress in tamoxifen-resistant cells. CONCLUSION: Our preclinical data provide evidence that FASN inhibition by TVB-3166 presents a promising therapeutic strategy for treatment of endocrine-resistant breast cancer. Further clinical development of FASN inhibitors for endocrine resistant breast cancer should be considered. Citation Format: Henriette Balinda. Inhibition of FASN as a potential treatment of advanced endocrine therapy-resistant breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-11-07.