Heterozygous RB1 mutation enhanced ATP production in human iPSC-derived retinal organoids.

BACKGROUND: Recent in vitro studies using RB1+/- fibroblasts and MSCs have shown molecular and functional disruptions without the need for biallelic loss of RB1. However, this was not reflected in the recent in vitro studies employing RB1+/- retinal organoids. To gain further insights into the molecular disruptions in the RB1+/- retinal organoids, we performed a high throughput RNA sequencing analysis. METHODS AND RESULTS: iPSCs were generated from RB1+/+ and RB1+/- OAMSCs derived from retinoblastoma patients. RB1+/+ and RB1+/- iPSCs were subjected to a step-wise retinal differentiation protocol. Retinal differentiation was evaluated by Real-time PCR and flow cytometry analysis of the retinal markers. To gain further insights into the molecular differences in RB1+/- retinal organoids, a high throughput RNA sequencing followed by differential gene expression analysis and gene set enrichment analysis (GSEA) was performed. The analysis revealed a shift from the regular metabolic process of glycolysis to oxidative phosphorylation in the RB1+/- retinal organoids. To investigate further, we performed assays to determine the levels of pyruvate, lactate and ATP in the retinal organoids. The results revealed significant increase in ATP and pyruvate levels in RB1+/- retinal organoids of day 120 compared to that of the RB1+/+. The results thus revealed enhanced ATP production in the RB1+/- retinal organoids. CONCLUSION: The study provides novel insights into the metabolic phenotype of heterozygous RB1 mutant suggesting dysregulation of energy metabolism and glycolytic pathways to be first step even before the changes in cellular proliferation or other phenotypic consequences ensue.

Congenital orbital fibrosis: report of two cases and review of literature.

A 7-year-old male child presented with complaints of lagophthalmos and lid retraction of the right eye since birth. Magnetic resonance imaging (MRI) showed diffuse thickening of right superior rectus and levator-palpebrae complex along with a hypointense, irregular, and ill-defined lesion in the adjoining fat abutting the lacrimal gland. Biopsy from the lesion showed diffuse orbital fibrosis. Another 3-year-old female child presented with complaints of her right eye appearing smaller and inability to move the right eye freely since birth. MRI showed thickening of right superior and medial recti with diffuse retrobulbar hypointense fibrotic strands. The findings were suggestive of orbital fibrosis. Congenital orbital fibrosis is an extremely rare orbital pathology with very few cases described in the literature. The most common clinical features are motility restriction, restrictive strabismus, upper lid retraction, enophthalmos, and proptosis. The diagnosis can be made on imaging but requires biopsy for confirmation. Management is mostly conservative in the form of refractive and amblyopia therapy.

A rare case of lacrimal sac dirofilariasis confirmed by polymerase chain reaction.

A 69-year-old female presented with complaints of persistent watering in the left eye for the past 8 years. She underwent a left external dacryocystorhinostomy (DCR) 8 years ago. On examination, left lacrimal passage irrigation showed regurgitation of fluid from opposite punctum. She underwent a revision external DCR with bicanalicular intubation and a portion of fibrosed sac was sent for histopathological examination (HPE). HPE showed a Microfilarial worm with surrounding granulomatous inflammation. Polymerase chain reaction (PCR) on the DNA extracted from the specimen identified the species to be Dirofilaria repens. Dirofilariasis is an accidental zoonotic infection in humans. Due to its migration, the worm can affect ocular and periocular structures. There are two case reports of perilacrimal dirofilariasis. This is the first case to report a filarial worm in the lacrimal sac causing chronic inflammation which probably led to failure of DCR. Treatment of choice is the complete eradication of the worm. PCR aids in the identification of species.

Retinoblastoma patient-derived stem cells-an in vivo model to study the role of RB1 in adipogenesis.

Retinoblastoma (RB1) protein is a multifunctional protein that plays an important role in cell cycle regulation and cell differentiation, including adipogenesis. A detailed literature search to understand the role of RB1 in adipogenesis revealed that the nature of the RB1 inactivation (in vivo/in vitro) led to differences in adipogenesis. The majority of these studies were animal-based, and the only study in humans employed an in vitro mode of RB1 inactivation. To overcome these differences and lack of human studies, we sought to explore the role of RB1 in adipogenesis using orbital adipose mesenchymal stem cells (OAMSCs) from patients with retinoblastoma that innately carry a heterozygous RB1 mutation. We hypothesized that these patient-derived RB1 mutant OAMSCs can model in vivo RB1 inactivation in humans. Our study revealed increased adipogenesis with a bias toward brown adipogenesis in the RB1 mutant in addition to an increased number of adipocytes in the mitotic phase.

Clinical profile and management outcomes of lacrimal drainage system malignancies.

PURPOSE: To report the clinical profile and management outcomes of a series of cases of malignant tumors of the lacrimal drainage system (LDS). MATERIALS AND METHODS: A retrospective analysis of all cases diagnosed with LDS malignancy over the past 24 years (1995-2019) was done. Patient characteristics, tumor types, management, and outcomes were analyzed. RESULTS: A total of 14 patients were included. Thirteen cases were of primary malignancy, while one was a secondary lesion. The mean age was 42.5 years, with males and females being equally affected. A medial canthal mass was the most common (9, 64.2%) presentation. Six patients (42.8%) had undergone one or more dacryocystorhinostomy surgeries for nasolacrimal duct obstruction before presentation. Seven patients underwent wide local excision (50%) while 3 (21.4%) each underwent dacryocystectomy and exenteration. Adjuvant radiation was administered to 4 (28.5%) patients. Thirteen (92.8%) patients were diagnosed with epithelial malignancy while one (7.1%) was a case of small B cell lymphoma. Transitional cell carcinoma was the most common epithelial malignancy (4, 28.5%). Three (21.4%) patients had metastatic disease (2 lymph nodes and one angle of jaw). There was no mortality after a mean follow up of 40.7+_25.1 months (Median 26; Range 4-131). CONCLUSION: LDS malignancy is rare, with the epithelial variant being far more common than non-epithelial. Wide local excision with adjuvant radiotherapy is the preferred management. Long-term follow-up is essential to manage recurrences and to increase survival.

Primary apocrine adenocarcinoma of the lacrimal sac: an extremely rare variant of lacrimal sac neoplasm.

A 52-year-old male presented with right eye prominence of 1-year duration. Right eye examination revealed proptosis and limitation of extraocular movements. Magnetic resonance imaging (MRI) of the orbit showed soft tissue mass in the inferomedial orbit with medial rectus involvement and involving lacrimal sac. The patient underwent an incisional biopsy. Histopathology confirmed a diagnosis of primary orbital adenocarcinoma. Positron emission tomography computed tomography (PET CT) did not show the involvement of any other organ. Right orbital exenteration was done for disease control. On histopathology the mass was found to be arising from the lacrimal sac and was reported as apocrine adenocarcinoma. The diagnosis was further confirmed by immunohistochemistry with the tumor staining positive for gross cystic disease fluid protein 15 (GCDFP 15). The patient received adjuvant radiotherapy and is alive without any recurrence at 1 year of follow up. Apocrine adenocarcinomas are rare malignant skin adnexal tumors. Involvement of lacrimal sac is extremely rare with only one case reported in the literature till date. Immunohistochemistry utilizing GCDFP 15 stain can confirm the diagnosis.

Heterozygous retinoblastoma gene mutation compromises in vitro osteogenesis of adipose mesenchymal stem cells - a temporal gene expression study.

Osteosarcoma (OS) is a bone malignancy affecting children and adolescents. Retinoblastoma (RB) patients with germline RB1 mutations are susceptible to osteosarcoma in the second decade of their life. Several studies, particularly in mice, have revealed a role for RB1 in osteogenesis. Since, there is species specific difference attributed in retinoblastoma tumorigenesis between mice and human, we assumed, it is worthwhile exploring the role of RB1 in osteogenesis and thus onset of osteosarcoma. In this study, we analyzed the temporal gene expression of the osteogenic markers, tumor suppressor genes and hormone receptors associated with growth spurt during in vitro osteogenesis of mesenchymal stem cells derived from orbital adipose tissue of germline RB patients and compared it with those with wild type RB1 gene. Mesenchymal stem cells with the heterozygous RB1 mutation showed reduced expression of RB1 and other tumor suppressor genes and showed deregulation of osteogenic markers which could be an initial step for the onset of osteosarcoma.

A rare case of congenital piloleiomyoma of the eyelid.

Cutaneous leiomyoma is an infrequently occurring benign smooth muscle neoplasm of skin. Piloleiomyoma, angioleiomyoma, and genital leiomyoma are the three forms of the cutaneous leiomyoma. Piloleiomyoma arises from arrector pili muscle and is commonly seen in the adult population. Congenital piloleiomyoma is extremely rare and has never been reported to arise from the eyelid. We report a case of a neonate presenting with upper eyelid mass lesion since birth causing mechanical ptosis. Incisional biopsy followed by histopathology and immunohistochemistry established the diagnosis of piloleiomyoma. There was associated cryptorchidism in our case, a systemic association that has never been reported. Considering the benign nature of the lesion the child was kept under regular follow up without attempting any further removal.

Intravitreal rituximab monotherapy for management of eyes with vitreoretinal lymphoma: initial experience from India.

PURPOSE: To evaluate treatment outcomes and complications of intravitreal rituximab (IVR) monotherapy for eyes with vitreoretinal lymphoma (VRL). METHODS: Patients diagnosed with 'isolated primary VRL' or 'VRL with remission of systemic disease' and treated with IVR (1 mg/0.1 ml) between June 2014 and June 2019 were included in this retrospective, interventional case series. Injections were repeated at monthly intervals until complete resolution. All patients signed a written informed consent form. Institutional review board approval was obtained. RESULTS: Twelve eyes of 7 patients with VRL were treated with 77 IVR injections at mean 6.42 injections per eye (median = 5; range = 2-13) for complete resolution at mean 8.16 ± 4.62 months (median = 6.97 months; range = 1.97-14.33 months). Mean age at presentation was 53.3 years (median = 54 years; range = 34-74 years). Patients were co-managed with medical oncologist and periodically evaluated. Complications included anterior uveitis (n = 6), raised intraocular pressure (n = 3), posterior synechiae (n = 2), vitreous haemorrhage (n = 1), pre-retinal haemorrhage (n = 1), retinal detachment (n = 1), posterior subcapsular cataract (n = 2) and sectoral iris atrophy (n = 1). Recurrences were seen in 3 eyes (25%), which eventually achieved complete resolution with treatment. None of the patients had systemic involvement or death during follow-up. Mean follow-up was 18.73 ± 8.83 months (median = 21.60 months; range = 7.37-32.67 months). CONCLUSION: Intravitreal rituximab monotherapy is effective in management of vitreoretinal lymphoma in patients with isolated ocular disease.

Gene expression profiling of tumor stroma interactions in retinoblastoma.

We aimed to identify the critical molecular pathways altered upon tumor stroma interactions in retinoblastoma (RB). In vitro 2 D cocultures of RB tumor cells (Weri-Rb-1 and NCC-RbC-51) with primary bone marrow stromal cells (BMSC) was established. Global gene expression patterns in coculture samples were assessed using Affymetrix Prime view human gene chip microarray and followed with bioinformatics analyses. Key upregulated genes from Weri-Rb-1 + BMSC and NCC-RbC-51 + BMSC coculture were validated using qRT-PCR to ascertain their role in RB progression. Whole genome microarray experiments identified significant (P ≤ 0.05, 1.1 log 2 FC) transcriptome level changes induced upon coculture of RB cells with BMSC. A total of 1155 genes were downregulated and 1083 upregulated in Weri-Rb-1 + BMSC coculture. Similarly, 1865 genes showed downregulation and 1644 genes were upregulation in NCC-RbC-51 + BMSC coculture. The upregulated genes were significantly associated with pathways of focal adhesion, PI3K-Akt signalling, ECM-receptor interaction, JAK-STAT, TGF-ß signalling thus contributing to RB progression. Validation of key genes by qRT-PCR revealed significant overexpression of IL8, IL6, MYC and SMAD3 in the case of Weri-Rb-1 + BMSC coculture and IL6 in the case of NCC-RbC-51 + BMSC coculture. The microarray expression study on in vitro RB coculture models revealed the pathways that could be involved in the progression of RB. The gene signature obtained in a stimulated model when a growing tumor interacts with its microenvironment may provide new horizons for potential targeted therapy in RB.

Serum exosomal miRNA as biomarkers for Retinoblastoma.

Retinoblastoma (RB) is a childhood eye tumor, caused by RB1 mutation. Though diagnosing RB is easier, prognosticating RB is limited to examining the patient under anesthesia and imaging technique. The aim of the study is to find exosomal miRNA biomarkers to prognosticate RB. Exosomes were isolated from one control - MIO-M1 and two RB cell lines - WERI-Rb-1 and NCC-RbC-51. Small RNA sequencing was performed on exosomal miRNA isolated from the three cell lines. miRNAs specific to each cell line were shortlisted. A total of 243, 606 and 400 miRNAs were identified in MIO-M1, WERI-Rb-1 and NCC-RbC-51 cell lines respectively. Nine miRNAs were shortlisted based on adjusted p value and literature, MIO-M1 specific (n = 1), WERI-RB-1 specific (n = 2), NCC-RbC-51 specific (n = 2) and miRNAs common to both RB cell lines (n = 4) were chosen. Validation was done using specific Taqman miRNA assays.miRNA validation was carried out on cell lines, cell line derived exosomes, primary RB tissues and exosomes isolated from serum of the RB patients. Validation of the miRNAs in cell lines and exosomes derived from the cell lines, confirmed the sequencing data. However, only 2 miRNAs - hsa-miR-301b-3p and hsa-miR-216b-5p were upregulated in the primary RB tissues. None of the miRNAs had significant expression in the serum exosomes of RB patients. Therefore, serum exosomal miRNA may not be ideal for prognosticating RB.Further research on other body fluids like CSF and vitreous could serve as potential source for biomarkers for prognosticating RB.

Correction to: EpCAM aptamer mediated cancer cell specific delivery of EpCAM siRNA using polymeric nanocomplex.

An amendment to this paper has been published and can be accessed via the original article.

Triton tumor of the orbit.

A triton tumor is a malignant peripheral nerve sheath tumor (MPNST) with rhabdomyomatous differentiation These tumors account for 5% of MPNSTs and have an extremely poor prognosis. We describe the case of a 14-year-old girl who presented with a history of painful, progressive protrusion of her right eye with a diminution of vision for the past five years. She had been diagnosed as having an embryonal rhabdomyosarcoma of the right orbit, and she had undergone surgical debulking followed by chemotherapy and radiotherapy. Despite undergoing multiple modalities of treatment, she had several recurrences prior to this consultation. We reviewed her histology slides. HPE features were consistent with a malignant triton tumor with cartilage and osseous differentiation. Immunohistochemistry was done to confirm the diagnosis. In view of the aggressive nature of the tumor with multiple recurrences; she was advised palliative radical excision to reduce the tumor burden.

Phosphoproteomics of Retinoblastoma: A Pilot Study Identifies Aberrant Kinases.

Retinoblastoma is a malignant tumour of the retina which most often occurs in children. Earlier studies on retinoblastoma have concentrated on the identification of key players in the disease and have not provided information on activated/inhibited signalling pathways. The dysregulation of protein phosphorylation in cancer provides clues about the affected signalling cascades in cancer. Phosphoproteomics is an ideal tool for the study of phosphorylation changes in proteins. Hence, global phosphoproteomics of retinoblastoma (RB) was carried out to identify signalling events associated with this cancer. Over 350 proteins showed differential phosphorylation in RB compared to control retina. Our study identified stress response proteins to be hyperphosphorylated in RB which included H2A histone family member X (H2AFX) and sirtuin 1. In particular, Ser140 of H2AFX also known as gamma-H2AX was found to be hyperphosphorylated in retinoblastoma, which indicated the activation of DNA damage response pathways. We also observed the activation of anti-apoptosis in retinoblastoma compared to control. These observations showed the activation of survival pathways in retinoblastoma. The identification of hyperphosphorylated protein kinases including Bromodomain containing 4 (BRD4), Lysine deficient protein kinase 1 (WNK1), and Cyclin-dependent kinase 1 (CDK1) in RB opens new avenues for the treatment of RB. These kinases can be considered as probable therapeutic targets for RB, as small-molecule inhibitors for some of these kinases are already in clinical trials for the treatment other cancers.

Probing the biophysical interaction between Neocarzinostatin toxin and EpCAM RNA aptamer.

Neocarzinostatin (NCS) a potent DNA-damaging, anti-tumor toxin extracted from Streptomyces carzinostaticus that recognizes double-stranded DNA bulge and induces DNA damage. 2 Fluoro (2F) Modified EpCAM RNA aptamer is a 23-mer that targets EpCAM protein, expressed on the surface of epithelial tumor cells. Understanding the interaction between NCS and the ligand is important for carrying out the targeted tumor therapy. In this study, we have investigated the biophysical interactions between NCS and 2-fluro Modified EpCAM RNA aptamer using Circular Dichroism (CD) and Infra-Red (IR) spectroscopy. The aromatic amino acid residues spanning the ß sheets of NCS are found to participate in intermolecular interactions with 2 F Modified EpCAM RNA aptamer. In-silico modeling and simulation studies corroborate with CD spectra data. Furthermore, it reinforces the involvement of C and D1 strand of NCS in intermolecular interactions with EpCAM RNA aptamer. This the first report on interactions involved in the stabilization of NCS-EpCAM aptamer complex and will aid in the development of therapeutic modalities towards targeted cancer therapy.

Proteomic profiling of retinoblastoma by high resolution mass spectrometry.

BACKGROUND: Retinoblastoma is an ocular neoplastic cancer caused primarily due to the mutation/deletion of RB1 gene. Due to the rarity of the disease very limited information is available on molecular changes in primary retinoblastoma. High throughput analysis of retinoblastoma transcriptome is available however the proteomic landscape of retinoblastoma remains unexplored. In the present study we used high resolution mass spectrometry-based quantitative proteomics to identify proteins associated with pathogenesis of retinoblastoma. METHODS: We used five pooled normal retina and five pooled retinoblastoma tissues to prepare tissue lysates. Equivalent amount of proteins from each group was trypsin digested and labeled with iTRAQ tags. The samples were analyzed on Orbitrap Velos mass spectrometer. We further validated few of the differentially expressed proteins by immunohistochemistry on primary tumors. RESULTS: We identified and quantified a total of 3587 proteins in retinoblastoma when compared with normal adult retina. In total, we identified 899 proteins that were differentially expressed in retinoblastoma with a fold change of ≥2 of which 402 proteins were upregulated and 497 were down regulated. Insulin growth factor 2 mRNA binding protein 1 (IGF2BP1), chromogranin A, fetuin A (ASHG), Rac GTPase-activating protein 1 and midkine that were found to be overexpressed in retinoblastoma were further confirmed by immunohistochemistry by staining 15 independent retinoblastoma tissue sections. We further verified the effect of IGF2BP1 on cell proliferation and migration capability of a retinoblastoma cell line using knockdown studies. CONCLUSIONS: In the present study mass spectrometry-based quantitative proteomic approach was applied to identify proteins differentially expressed in retinoblastoma tumor. This study identified the mitochondrial dysfunction and lipid metabolism pathways as the major pathways to be deregulated in retinoblastoma. Further knockdown studies of IGF2BP1 in retinoblastoma cell lines revealed it as a prospective therapeutic target for retinoblastoma.

In vitro transdifferentiation of human skin keratinocytes to corneal epithelial cells.

BACKGROUND AIMS: Skin keratinocytes (SKs) share the same surface ectodermal origin as that of corneal epithelium. In this study, the plasticity of epidermal keratinocytes was exploited to generate corneal epithelial-like cells, which might serve as an alternative source of autologous tissue for the treatment of bilateral limbal stem cell deficiency. METHODS: Skin samples were subjected to collagenase digestion to isolate SKs and transdifferentiated to corneal epithelial-like cells using limbal fibroblast conditioned medium (LFCM). SKs and transdifferentiated corneal epithelial cells (TDCECs) were characterized using immunofluorescence and fluorescence-activated cell sorting. The propensity for expression of angiogenic genes in TDCECs was compared with cultured oral mucosal epithelial cells (COMEC) in vitro. RT(2) quantitative polymerase chain reaction profiler array was performed to study the signaling pathways involved in the transdifferentiation process. RESULTS: The TDCECs obtained from SKs showed corneal epithelial-like morphology and expressed corneal epithelial markers, CK3 and CK12. Hematoxylin-eosin and immunohistochemistry showed stratified layers of TDCECs expressing CK 3/12, confirming the corneal epithelial phenotype. We found that the expression of several angiogenic and epithelial mesenchymal transition factors were down-regulated in TDCECs compared with COMEC, suggesting a lower capacity to induce angiogenesis in TDCECs. There was considerable difference in the signaling mechanisms between TDCECs and SKs on testing by RT(2) profiler array, signifying differences at the global gene profile. The comparison of TDCECs and limbal derived corneal epithelial cells showed similar gene expression. DISCUSSION: Our study shows that SKs have the potential to transdifferentiate into corneal epithelial-like cells using LFCM.

Monitoring of changes in lipid profiles during PLK1 knockdown in cancer cells using DESI MS.

The importance of the polo-like kinase 1 (PLK1) gene is increasing substantially both as a biomarker and as a target for highly specific cancer therapy. This is due to its involvement in multiple points of cell progression and carcinogenesis. PLK1 inhibitors' efficacy in treating human cancers has been limited due to the lack of a specific targeting strategy. Here, we describe a method of targeted downregulation of PLK1 in cancer cells and the concomitant rapid detection of surface lipidomic perturbations using desorption electrospray ionization mass spectrometry (DESI MS). The efficient delivery of siRNA targeting PLK1 gene selectively to the cancer cells is achieved by targeting overexpressed cell surface epithelial cell adhesion molecule (EpCAM) by the EpDT3 aptamer. The chimeric aptamer (EpDT3-siPLK1) showed the knockdown of PLK1 gene expression and PLK1 protein levels by quantitative PCR and western blotting, respectively. The abundant surface lipids, phosphatidylcholines (PCs), such as PC(32:1) (m/z 754.6), PC(34:1) (m/z 782.6), and PC(36:2) (m/z 808.6), were highly expressed in MCF-7 and WERI-RB1 cancer cells compared to normal MIO-M1 cells and they were observed using DESI MS. These overexpressed cell surface lipids in the cancer cells were downregulated upon the treatment of EpDT3-siPLK1 chimera indicating a novel role of PLK1 to regulate surface lipid expression in addition to the efficient selective cancer targeting ability. Our results indicate that DESI MS has a potential ability to rapidly monitor aptamer-mediated cancer therapy and accelerate the drug discovery process. Graphical abstract Binding of aptamer chimera to the cells and changes in lipid profile.

A Study of Gene Expression of Survivin, its Antiapoptotic Variants, and Targeting Survivin In Vitro for Therapy in Retinoblastoma.

Apoptosis is a natural process regulated by apoptotic and antiapoptotic molecules. We investigated mRNA expression of survivin and its splice variants, along with B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X (Bax), in a cohort of 20 retinoblastoma (RB) tumors by real-time polymerase chain reaction. We hypothesized a correlation between the Bcl-2/Bax and survivin splice variants and also that expression of these would be associated with clinicopathologic features of tumors. The Bcl-2 expression was significantly higher (P<0.001) in RB, and Bcl-2/Bax ratio was remarkably higher in poorly differentiated tumors. A statistically significant higher expression of Survivin-WT (wild type) compared with its variant Survivin-2ß (P<0.05) was observed. Bcl-2 did not exhibit positive correlation with any of the survivin variants except Survivin-2ß, whereas Bax exhibited significant (P<0.05) correlation with the variants. Thus, it could be suggested that a superior player out of a likely interaction between the variants and Bcl-2/Bax uses its activity for the progression of RB. Silencing of Survivin-WT in the Y79 cell line was studied by siRNA technology and cell-permeable dominant negative survivin (SurR9-C84A). siRNA showed higher proapoptotic effects and increased caspase 3/7 activity in Y79 cells. Effective internalization of SurR9-C84A in Y79 cells induced cytotoxic effects. Thus, the current study confirms survivin as a promising target for therapy.