Effect of Eriodictyol on Retinoblastoma via the PI3K/Akt Pathway

Retinoblastoma (RB) is one of the most common intraocular malignancies in children, which causes vision loss and even threatens life. Eriodictyol is a natural flavonoid with strong anticancer activity. Some studies have shown that eriodictyol exerts anticancer effects in glioma, colon cancer, and lung cancer; however, no studies have reported the anticancer effects of eriodictyol on RB. Therefore, the aim of this study was to investigate the anticancer activity of eriodictyol against the RB Y79 cell line and its potential mechanism of action. Interestingly, we found that eriodictyol inhibited the proliferation, migration, and invasion of Y79 cells in a dose-dependent manner and decreased the expression of MMP-2 and MMP-9 proteins in the cells. In addition, eriodictyol-induced apoptosis in Y79 cells was assessed by flow cytometry and immunoblotting. Here, our study revealed that eriodictyol dose dependently inhibited the activation of the PI3K/Akt signaling pathway. Notably, the effect of eriodictyol on RB apoptosis was reversed by a PI3K agonist 740 Y-P. In conclusion, our study shows that eriodictyol effectively inhibits proliferation, migration, and invasion and induces apoptosis in RB cell lines, which may be the result of blocking the PI3K/Akt signaling pathway. Thus, eriodictyol may provide a new theoretical basis for exploring targeted antitumor natural therapies.

Cyclophosphamide inhibits Pax5 methylation to regulate the growth of retinoblastoma via the Notch1 pathway

Retinoblastoma (Rb) is the most common intraocular malignant tumor in infants. Here, we investigated the function and mechanism of cyclophosphamide (CTX) in the development of Rb. Real-time quantitative polymerase chain reaction (RT-qPCR) results showed that paired box protein 5 (Pax5) expression was down-regulated in Rb tissues and cell lines. Methylation-specific PCR (MSP) results showed that the methylation level of Pax5 was up-regulated in Rb. After treatment with CTX, the Pax5 expression in Rb cell lines was increased significantly. The methylation of Pax5 and the expression of DNA methyltransferases (DNMTs) were down-regulated in the CTX group. Cyclophosphamide inhibited cell proliferation, migration, and invasion, promoted cell apoptosis via the Notch1 pathway. DNA methyltransferase inhibitor SGI-1027 had synergistic effects with CTX. Paired box protein 5 siRNA was transfected into Y79 cells treated with CTX. The expression of DNMTs, Pax5, the Notch1 pathway and apoptosis marker protein was detected by Western blotting, and changes in cell behavior were detected, respectively. Results showed that knockdown of Pax5 reversed the effects of CTX. Moreover, the Notch1 activator Valproic acid (VPA) abolished the inhibitory effects of CTX on Rb development. Moreover, CTX inhibited tumor growth in nude mice. These findings demonstrated that CTX up-regulated Pax5 expression by down-regulating DNMTs expression, and then inhibited the Notch1 signaling pathway activation and Rb growth.

Effect of Andrographis paniculata polysaccharide on human retinoblastoma Y79 cell proliferation and apoptosis

AIM: To explore the effect of the Andrographis paniculata (A. paniculata) polysaccharide on the proliferation and apoptosis of human retinoblastoma (RB) Y79 cells and its mechanism. METHODS: The refined A. paniculata polysaccharide was obtained using techniques such as water extraction, ethanol precipitation, and decompression concentration. The inhibition effect of the A. paniculata polysaccharide on the proliferation of Y79 cells was detected by cell proliferation assay. Flow cytometry was used for the detection of cell apoptosis rate and cycle change. Real-time qunatitative polymerase chain reaction (RT qPCR)and Western blotting were used to detect the expression of cell apoptosis signal pathway-related factors (caspase-3, caspase-8, and caspase-9) and cell cycle signal pathway-related factors (CDK1 and cyclinB1) at the transcriptional and translational levels. RESULTS: Infrared and ultraviolet spectrum scanning showed that the extracted drug was a polysaccharide with high purity. After being treated with different concentrations of A. paniculata polysaccharide for different periods of time, the Y79 cells showed different degrees of proliferation inhibition. Flow cytometric observations showed that the cell apoptosis rate and the proportion of cells blocked in the G2/M phase were significantly increased after A. paniculata polysaccharide treatment. Further analysis revealed that the mRNA and protein expression of caspase-3, caspase-8, and caspase-9 in the A. paniculata polysaccharide treatment groups increased significantly compared with that in the control groups, while the expression of CDK1 and cyclinB1 decreased significantly. CONCLUSION: The A. paniculata polysaccharide could inhibit the proliferation and induce apoptosis of Y79 cells. Its possible mechanism is via the upregulation of caspase-3, caspase-8, and caspase-9 expression in the cell apoptotic signaling pathway and the downregulation of CDK1 and cyclinB1 expression in the cell cycle signaling pathway.

Bisphenol A Exposure Changes the Transcriptomic and Proteomic Dynamics of Human Retinoblastoma Y79 Cells

Bisphenol A (BPA) is a xenoestrogen chemical commonly used to manufacture polycarbonate plastics and epoxy resin and might affect various human organs. However, the cellular effects of BPA on the eyes have not been widely investigated. This study aimed to investigate the cellular cytotoxicity by BPA exposure on human retinoblastoma cells. BPA did not show cytotoxic effects, such as apoptosis, alterations to cell viability and cell cycle regulation. Comparative analysis of the transcriptome and proteome profiles were investigated after long-term exposure of Y79 cells to low doses of BPA. Transcriptome analysis using RNA-seq revealed that mRNA expression of the post-transcriptional regulation-associated gene sets was significantly upregulated in the BPA-treated group. Cell cycle regulation-associated gene sets were significantly downregulated by exposure to BPA. Interestingly, RNA-seq analysis at the transcript level indicated that alternative splicing events, particularly retained introns, were noticeably altered by low-dose BPA treatment. Additionally, proteome profiling using MALDI-TOF-MS identified a total of nine differentially expressed proteins. These results suggest that alternative splicing events and altered gene/protein expression patterns are critical phenomena affected by long-term low-dose BPA exposure. This represents a novel marker for the detection of various diseases associated with environmental pollutants such as BPA.

The Synergistic Cytotoxic and Apoptotic Effect of Resveratrol and Naringenin on Y79 Retinoblastoma Cell Line

Background: Resveratrol is a phenolic natural product which is found in red grapes also in Japanese knotweed root (Polygonum cuspidatum). Naringenin is one of the flavonoid compounds found in landing grape and other citrus fruits. Both agents exert antioxidant and anti-inflammatory properties. Objective: In this study, we investigated the effect of Resveratrol and Naringenin in an in vitro model of retinoblastoma of the eye. Method: XTT and trypan blue assays used to evaluate the anti-proliferative/cytotixic effect of resveratrol and naringenin in Y79 cells. By the aid of AnnexinV/PI flow cytometry the kind of cell death investigated. To asses important gene expression level at mRNA level involve in apoptosis, Real-time PCR utilized. Results: Naringenin and resveratrol significantly decreased proliferation and stimulated cell death (mostly apoptosis) in Y79 cells at 50 and 100 (μg/ml) after 24 and 48 hours. More cytotoxic effect observed after 48 hours. Furthermore expression level of Bax and Bcl2 mRNAs altered significantly in all samples treated with 50 (μg/ml) of naringenin, resveratrol, or simultaneously with both. P21 mRNAs expression altered in all mentioned samples except those treated with 50 (μg/ml) of resveratrol. Results: Naringenin and resveratrol significantly decreased proliferation and stimulated cell death (mostly apoptosis) in Y79 cells at 50 and 100 (μg/ml) after 24 and 48 hours. More cytotoxic effect observed after 48 hours. Furthermore expression level of Bax and Bcl2 mRNAs altered significantly in all samples treated with 50 (μg/ml) of naringenin, resveratrol, or simultaneously with both. P21 mRNAs expression altered in all mentioned samples except those treated with 50 (μg/ml) of resveratrol. Conclusion: Based on the results, it can be concluded that resveratrol and naringenin can decrease cell viability in retinoblastoma cells in an in vitro dose/time-dependent manner. Albeit more studies needed to shed the light on the mechanism of action, our data reveals a potential synergistic cytotoxic effect of naringenin and resveratrol on Y79 cells in 48 hours.

Knockdown of lncRNA HOTTIP Inhibits Retinoblastoma Progression by Modulating the miR-101-3p/STC1 Axis

Objective: Retinoblastoma (RB) is a frequent eye cancer in children. Long non-coding RNA (LncRNA) HOXA transcript at the distal tip (HOTTIP) is aberrantly expressed in cancer tissues. This study explores the underlying mechanism of lncRNA HOTTIP in RB. Methods: HOTTIP expression in normal retinal cells and RB cell lines was detected using qRT-PCR. The proliferation of RB cells was measured using CCK-8 and EdU assays, and apoptosis was detected using flow cytometry and Western blotting after the transfection of si-HOTTIP into Y79 cells and pc-HOTTIP into HXO-RB-44 cells. The target relationships between HOTTIP and miR-101-3p, and miR-101-3p and STC1 were predicted by bioinformatics website and verified using dual-luciferase reporter gene assay. The binding of HOTTIP and miR-101-3p was verified using RNA pull-down assay. STC1 mRNA and protein in RB cells were measured using qRT-PCR and Western blotting. Moreover, si-HOTTIP and in-miR-101-3p/in-NC, and si-HOTTIP and pc-STC1/pcDNA were co-transfected into Y79 cells respectively to evaluate cell proliferation and apoptosis. Xenograft study was conducted, and Ki67-positive expression was detected using immunohistochemical staining. Results: HOTTIP expression was promoted in RB tissues and cells. Downregulation of HOTTIP inhibited proliferation and promoted apoptosis of Y79 cells, while upregulation of HOTTIP promoted proliferation and inhibited apoptosis of HXO-RB-44 cells. There were target relationships between HOTTIP and miR-101-3p, and miR-101-3p and STC1. Inhibition of miR-101-3p or overexpression of STC1 reversed the effect of si-HOTTIP on the proliferation and apoptosis of RB cells. Xenograft study showed that knockdown of HOTTIP suppressed the growth of RB in vitro. Conclusion: It could be concluded that HOTTIP sponged miR-101-3p to upregulate STC1 expression, thereby promoting RB cell proliferation and inhibiting apoptosis.

CE-CAM model for evaluating CD133lo Cancer Stem Cells in Retinoblastoma

BackgroundCancer Stem Cells (CSCs) reported in various tumors, play a crucial role in tumorigenesis and metastasis. Following the efforts to reduce, replace and refine the use of mammalian models, we aimed to establish a short-term xenograft for Retinoblastoma (Rb) to evaluate the tumorigenic and metastatic potential of CD133lo CSCs in Rb Y79 cells, using the well-established chick embryo (CE) model. MethodsTotal and CD133 sorted Rb Y79 cells, labelled with eGFP/CM-Dil tracking dye, were transplanted onto the chorioallantoic membrane (CAM) of day-7 chick embryos and incubated for 7 days. The tumor formation on CAM and metastasis to the embryos were evaluated by confocal microscopy, in-vivo imaging, and histopathology. ResultsY79 cells formed pink-white raised perivascular nodules on the CAM with CD133lo CSCs exhibiting larger nodules when compared to CD133hi cells and total Y79 (p<0.05). In-vivo imaging revealed that the labeled cells metastasized to the embryos with the fluorescent signals visible in the abdominal area, cephalus and the limbs. Histopathologic studies confirmed the presence of tumor cells on the CAM, organs of embryos transplanted with Y79 cells, more so with CD133lo CSCs. ConclusionsThis study highlights that the CE-CAM is a feasible alternative non-mammalian model for evaluating tumorigenicity and metastatic potential of Rb CSCs. The study also provides preliminary evidence that Rb Y79 CD133lo CSCs show higher propensity to form tumor nodules on the CAM and are more invasive than non CSCs, thus, supporting our earlier evidence that they are endowed with CSC properties.