Retinoblastoma Is Characterized by a Cold, CD8+ Cell Poor, PD-L1- Microenvironment, Which Turns Into Hot, CD8+ Cell Rich, PD-L1+ After Chemotherapy

Expression of Cell Cycle Markers and Proliferation Factors during Human Eye Embryogenesis and Tumorigenesis

The expression pattern of the markers p19, Ki-67, MSX1, MSX2, PDL1, pRB, and CYCLINA2 was quantitatively and semiquantitatively analyzed in histologic sections of the developing and postnatal human eye at week 8, in retinoblastoma, and in various uveal melanomas post hoc studies by double immunofluorescence. The p19 immunoreactivity characterized retinal and/or choroidal cells in healthy and tumor tissues: expression was lower in the postnatal retina than in the developing retina and retinoblastoma, whereas it was high in epithelioid melanomas. Ki67 expression was high in the developing eye, retinoblastoma, and choroidal melanomas. MSX1 and MSX2 expression was similar in the developing eye and retinoblastoma, whereas it was absent in the postnatal eye. Their different expression was evident between epithelioid and myxoid melanomas. Similarly, PDL1 was absent in epithelioid melanomas, whereas it was highly expressed in developing and tumor tissues. Expression of pRB and CYCA2 was characteristic of developing and tumorous eye samples but not of the healthy postnatal eye. The observed expression differences of the analyzed markers correlate with the origin and stage of cell differentiation of the tissue samples. The fine balance of expression could play a role in both human eye development and ocular tumorigenesis. Therefore, understanding their relationship and interplay could open new avenues for potential therapeutic interventions and a better understanding of the mechanisms underlying the developmental plasticity of the eye and the development of neoplasms.

UBE2T is a prognostic biomarker and correlated with Th2 cell infiltrates in retinoblastoma

OBJECTIVE

This study aimed to screen anaplasia-related genes that influence the progression of retinoblastoma (RB) and to identify immune cells associated with the poor prognosis.

METHODS

Differentially expressed genes (DEGs) between retina and RB samples were acquired from gene expression omnibus (GEO) database. Candidate hub genes were screened by taking intersections among the co-expressed genes, the hub nodes, and DEGs of the validation set. The hub genes were identified by receiver operating characteristic (ROC) and quantitative real-time PCR (qPCR). Immune infiltration levels of RB tissues were estimated using single-sample gene set enrichment analysis (ssGSEA). The functions of RB cells were detected by CCK8, EDU and flow cytometry assays.

RESULTS

665 DEGs involved in the genesis and progression of RB were acquired from GEO database. 29 candidate hub genes were screened by examining 43 co-expressed genes and 63 hub nodes. 9 hub genes (CHEK1, EXO1, FANCI, GTSE1, MELK, MKI67, NCAPH, PRC1, and UBE2T) strongly related to the anaplastic grades were validated by ROC curve analysis (AUC >0.8). Based on the ssGSEA scores, the immune infiltration levels of Th2 cells were positively associated with anaplastic grade. qPCR assay showed that 9 hub genes were upregulated in RB cells, and UBE2T expressed remarkably high. CCK 8, EDU, and flow cytometry assays revealed that UBE2T silencing inhibited the proliferation of RB cells and incited apoptosis.

CONCLUSIONS

The increased infiltration of Th2 cells and upregulated expression of 9 hub genes predict a poor prognosis of RB. UBE2T can be a therapeutic target for RB treatment.

Single-cell characterization of malignant phenotypes and microenvironment alteration in retinoblastoma

Retinoblastoma (RB) is the most common primary intraocular malignancy of childhood. It is known that the tumor microenvironment (TME) regulates tumorigenesis and metastasis. However, how the malignant progression in RB is determined by the heterogeneity of tumor cells and TME remains uncharacterized. Here, we conducted integrative single-cell transcriptome and whole-exome sequencing analysis of RB patients with detailed pathological and clinical measurements. By single-cell transcriptomic sequencing, we profiled around 70,000 cells from tumor samples of seven RB patients. We identified that the major cell types in RB were cone precursor-like (CP-like) and MKI67+ cone precursor (MKI67+ CP) cells. By integrating copy number variation (CNV) analysis, we found that RB samples had large clonal heterogeneity, where the malignant MKI67+ CP cells had significantly larger copy number changes. Enrichment analysis revealed that the conversion of CP-like to MKI67+ CP resulted in the loss of photoreceptor function and increased cell proliferation ability. The TME in RB was composed of tumor-associated macrophages (TAMs), astrocyte-like, and cancer-associated fibroblasts (CAFs). Particularly, during the invasion process, TAMs created an immunosuppressive environment, in which the proportion of TAMs decreased, M1-type macrophage was lost, and the TAMs-related immune functions were depressed. Finally, we identified that TAMs regulated tumor cells through GRN and MIF signaling pathways, while TAMs self-regulated through inhibition of CCL and GALECTIN signaling pathways during the invasion process. Altogether, our study creates a detailed transcriptomic map of RB with single-cell characterization of malignant phenotypes and provides novel molecular insights into the occurrence and progression of RB.

Treatment of Retinoblastoma: What Is the Latest and What Is the Future

The management of retinoblastoma, the most common intraocular malignancy in children, has changed drastically over the last decade. Landmark developments in local drug delivery, namely, safer techniques for intravitreal chemotherapy injection and ophthalmic artery chemosurgery, have resulted in eye globe salvages that were not previously attainable using systemic chemotherapy or external beam irradiation. Novel drugs, oncolytic viruses, and immunotherapy are promising approaches in the treatment of intraocular retinoblastoma. Importantly, emerging studies of the pattern of tumor dissemination and local drug delivery may provide the first steps toward new treatments for metastatic disease. Here, we review recent advances in retinoblastoma treatment, especially with regard to local drug delivery, that have enabled successful conservative management of intraocular retinoblastoma. We also review emerging data from preclinical and clinical studies on innovative approaches that promise to lead to further improvement in outcomes, namely, the mechanisms and potential uses of new and repurposed drugs and non-chemotherapy treatments, and discuss future directions for therapeutic development.

SOX2 maintains the stemness of retinoblastoma stem-like cells through Hippo/YAP signaling pathway

PURPOSE

To explore the mechanisms underlying stemness maintenance of retinoblastoma (RB) stem cells (RSCs).

METHODS

The retinoblastoma stem-like cells (RSLCs) were isolated by single cell cloning in combination of examination of sphere-forming capacities. The stemness of the cells were characterized by the sphere-forming capacity and the expression levels of RSCs markers. Gene manipulation was performed by lentivirus system. Transcriptional regulation was identified by qRT-PCR, luciferase reporter, nuclear run-on and DNA pull-down assay. Spearman analysis was employed for correlation analysis of genes in tumor tissues of RB patients.

RESULTS

The isolated RSLCs exhibited enhanced sphere-forming capacity and constantly higher levels of CD44, ABCG2, SOX2 and PAX6, but not CD133. SOX2 positively regulated the stemness of RSLCs. SOX2 directly binds to the promoters of WWTR1 and YAP and transcriptionally activates WWTR1 and YAP. Knockdown of WWTR1 or YAP partially abolished the effect of SOX2 on the stemness of RSLCs.

CONCLUSIONS

SOX2, as a key deriver, maintains RB stemness by activating Hippo/YAP signaling. Inhibition of Hippo/YAP signaling would be an effective strategy for human RB caused by SOX2 upregulation.