Retinoblastoma (Rb) is the most prevalent intraocular malignancy in children, with a worldwide survival rate <30%. We have developed a cancerous model of Rb in retinal organoids derived from genetically engineered human embryonic stem cells (hESCs) with a biallelic mutagenesis of the RB1 gene. These organoid Rbs exhibit properties highly consistent with Rb tumorigenesis, transcriptome, and genome-wide methylation. Single-cell sequencing analysis suggests that Rb originated from ARR3-positive maturing cone precursors during development, which was further validated by immunostaining. Notably, we found that the PI3K-Akt pathway was aberrantly deregulated and its activator spleen tyrosine kinase (SYK) was significantly up-regulated. In addition, SYK inhibitors led to remarkable cell apoptosis in cancerous organoids. In conclusion, we have established an organoid Rb model derived from genetically engineered hESCs in a dish that has enabled us to trace the cell of origin and to test novel candidate therapeutic agents for human Rb, shedding light on the development and therapeutics of other malignancies.

IntroductionPaclitaxel (Taxol®) is a microtubule-targeted agent that is widely used for cancer treatment. However, resistance to paclitaxel is frequently encountered in the clinic. There is increasing interest in identifying compounds that may increase the sensitivity to conventional chemotherapeutic agents. In this study, we investigated whether green tea polyphenol (-)-epigallocatechin gallate (EGCG) could sensitize breast carcinoma to paclitaxel in vivo.MethodsBreast cancer cells were treated with or without EGCG and paclitaxel followed by detection of cell survival and apoptosis. c-Jun NH2-terminal kinase (JNK) phosphorylation and glucose-regulated protein 78 (GRP78) expression were detected by Western blotting. For in vivo study, 4T1 breast cancer cells were inoculated into Balb/c mice to establish a transplantation model. The tumor-bearing mice were treated with or without EGCG (30 mg/kg, i.p.) and paclitaxel (10 mg/kg, i.p.). Tumor growth was monitored. Apoptosis in tumor tissues was detected. Cell lysates from tumors were subjected to Western blot analysis of GRP78 expression and JNK phosphorylation.ResultsEGCG synergistically sensitized breast cancer cells to paclitaxel in vitro and in vivo. EGCG in combination with paclitaxel significantly induced 4T1 cells apoptosis compared with each single treatment. When tumor-bearing mice were treated with paclitaxel in combination with EGCG, tumor growth was significantly inhibited, whereas the single-agent activity for paclitaxel or EGCG was poor. EGCG overcame paclitaxel-induced GRP78 expression and potentiated paclitaxel-induced JNK phosphorylation in 4T1 cells both in vitro and in vivo.ConclusionsEGCG may be used as a sensitizer to enhance the cytotoxicity of paclitaxel.

Abstract. The aim of this study was to identify and evaluate microRNAs (miRNAs) in gastric cancer lymph node metastasis. A miRNA array was used to compare the expression of miRNAs in primary gastric cancer and paired lymph node metastases. miRNAs found to be differentially expressed were validated in a cohort of primary gastric cancer tissues, and the relationship between expression and the clinicopathological characteristics of the specimens was analyzed. The expression level of miR-10a in a gastric mucosal cell line and three gastric cancer cell lines was also detected using qPCR. Moreover, the target genes for miR-10a were predicted using bioinformatic methods. Based on the results, four differentially expressed miRNAs were detected by the miRNA array. Compared with primary gastric cancer, lymph node metastases displayed downregulated expression of miR-24-1 * , miR-510 and miR-1284, while the expression of miR-10a was upregulated. Consequently, analysis found that the expression of miR-10a was associated with lymph node metastasis (P=0.047), but was independent of the state of lymphatic invasion (P=0.169) in the cohort of primary gastric carcinoma. The expression of miR-10a was at least 10-fold higher in the three gastric cancer cell lines than in the gastric mucosal cell line. Two gastric cancer cell lines, which were established from lymph node metastasis, expressed higher miR-10a compared to the primary tumor origin cell line. Bioinformatic analysis demonstrated that the target genes of miR-10a are involved in multiple related pathways of tumorigenesis and metastasis. In conclusion, our study suggests that miR-10a is involved in the development of gastric cancer and lymph node metastasis, particularly in the latter process. IntroductionGastric cancer is one of the most common malignant tumors of the digestive system, and its early diagnosis rate is still low in China, where gastric cancer is typically diagnosed at a more advanced stage; metastasis is typically present at the time of diagnosis. However, conventional strategies based on radical surgery for the treatment of gastric cancer are not yet satisfactory. Therefore, investigation of the mechanisms of metastasis and recurrence of gastric cancer, and exploration of the methods for the effective prediction, prevention and treatment of tumor metastasis are attracting increased attention in both basic and clinical cancer research. microRNAs (miRNAs), discovered in 1993, are a class of non-coding RNAs 19-25 nt in length that regulate gene expression at the post-transcriptional level (1,2). These miRNAs regulate complicated cellular processes such as differentiation, proliferation and apoptosis (3) and are widely involved in tumorigenesis, tumor progression and metastasis (4,5). Recent research suggests that miRNAs are involved in tumor invasion and metastasis, in the context of breast cancer, colorectal cancer, esophageal squamous cell carcinoma, and pancreatic endocrine tumors (6,7). Few studies have reported the role of miRNAs in gastric cancer owing to ...

Although an increasing number of disease genes have been identified, the exact cellular mechanisms of retinitis pigmentosa (RP) remain largely unclear. Retinal organoids (ROs) derived from the induced pluripotent stem cells (iPSCs) of patients provide a potential but unvalidated platform for deciphering disease mechanisms and an advantageous tool for preclinical testing of new treatments. Notably, early-onset RP has been extensively recapitulated by patient-iPSC-derived ROs. However, it remains a challenge to model late-onset disease in a dish due to its chronicity, complexity, and instability. Here, we generated ROs from late-onset RP proband-derived iPSCs harboring a PDE6B mutation. Transcriptome analysis revealed a remarkably distinct gene expression profile in the patient ROs at differentiation day (D) 230. Changes in the expression genes regulating cGMP hydrolysis prompted the elevation of cGMP levels, which was verified by a cGMP enzyme-linked immunosorbent assay (ELISA) in patient ROs. Furthermore, significantly higher cGMP levels in patient ROs than in control ROs at D193 and D230 might lead to impaired formation of synaptic connections and the connecting cilium in photoreceptor cells. In this study, we established the first late-onset RP model with a consistent phenotype using an in vitro cell culture system and provided new insights into the PDE6B-related mechanism of RP.