Inhibitory effect of carboplatin in combination with bevacizumab on human retinoblastoma in an in vitro and in vivo model

Ramucirumab combination with sorafenib enhances the inhibitory effect of sorafenib on HepG2 cancer cells

Sorafenib, an oral multiple kinase inhibitor, is the standardized treatment for hepatocellular carcinoma (HCC). One strategy to improve HCC therapy is to combine agents that target key signaling pathways. In this study we set out to investigate the effect of combining sorafenib with either bevacizumab (anti-VEGF), panitumumab (anti-EGFR) or ramucirumab (anti-VEGFR2) on HepG2 cancer cell line with the aim of improving efficacy and possibility of therapeutic dose reduction of sorafenib.: HepG2 cancer cell line was treated with sorafenib alone or in combination with either bevacizumab, panitumumab or ramucirumab. Cell proliferation; apoptosis and cell cycle distribution; gene expression of VEGFR2, EGFR, MMP-9 and CASPASE3; the protein levels of pVEGFR2 and pSTAT3 and the protein expression of CASPASE3, EGFR and VEGFR2 were determined. Combined treatments of sorafenib with ramucirumab or panitumumab resulted in a significant decrease in sorafenib IC₅₀. Sorafenib combination with ramucirumab or bevacizumab resulted in a significant arrest in pre-G and G0/G1 cell cycle phases, significantly induced apoptosis and increased the relative expression of CASPASE3 and decreased the anti-proliferative and angiogenesis markers´ MMP-9 and pVEGFR2 or VEGFR2 in HepG2 cells. A significant decrease in the levels of pSTAT3 was only detected in case of sorafenib-ramucirumab combination. The combined treatment of sorafenib with panitumumab induced a significant arrest in pre-G and G2/M cell cycle phases and significantly decreased the relative expression of EGFR and MMP-9. Sorafenib-ramucirumab combination showed enhanced apoptosis, inhibited proliferation and angiogenesis in HepG2 cancer cells. Our findings suggest that ramucirumab can be a useful as an adjunct therapy for improvement of sorafenib efficacy in suppression of HCC.

Extracorporeal Shock Wave Therapy Salvages Critical Limb Ischemia in B6 Mice through Upregulating Cell Proliferation Signaling and Angiogenesis

(1) This study tests hypothesis whether extracorporeal shock wave (ECSW) therapy effectively salvages mouse critical limb ischemia (CLI). In vitro result demonstrated that the angiogenesis parameters (i.e., tubular length/cluster/network formation) and protein expressions of EGFR/VEGFR2/RAS/c-Raf/MEK/ERK/VEGF/p-PI3K/p-Akt/p-m-TOR were significantly and progressively increased with stepwise augmentation of ECSW energy (0.1/0.14/0.20 mJ/mm²/140 impulses). On the other hand, they were suppressed by administration of Avastin (20 μM). Adult male B6 mice (n = 24) were equally categorized into group 1 (sham-operated control), group 2 (CLI), group 3 [CLI + ECSW (0.12 mJ/mm²/120 impulses/at days 1/3/7 after CLI induction)] and group 4 [CLI + ECSW (0.12 mJ/mm²/120 impulses) + Avastin (1 mg/intramuscular-injection)] at days 1/3/7 after CLI induction] and quadriceps were harvested by day 14. The laser Doppler result showed that the ratio of left (ischemia) to right (normal) limb blood flow was highest in group 1, lowest in group 2, and significantly higher in group 3 than in group 4 by days 7/14 after the CLI procedure (p < 0.0001). The protein expressions of cell proliferation/migration/angiogenesis receptors (EGFR/VEGFR2), angiogenesis biomarkers (VEGF/CXCR4/SDF-1) and cell proliferation/growth/survival (Ras/c-Raf/MEK/ERK)/(PI3K/Akt/m-TOR) and cell motility/proliferation (p-FAK/p-Scr) signaling biomarkers were significantly higher in group 3 than in groups 1/2/4, and significantly lower in group 1 than in groups 2/4, but they did not show a difference between groups 2 and 4 (all p < 0.001). The small vessel density and cellular levels of endothelial cell surface marker (CD31+) exhibited an identical pattern of blood flow, whereas the angiogenesis (CXCR4+/VEGF+) displayed an identical pattern of VEGFR2 among the groups (all p < 0.0001). The in vitro and in vivo studies found ECSW salvaged the CLI mainly through upregulating Ras-Raf-MEK/ERK/cell motility, cell proliferation/growth pathways and angiogenesis.

Downregulation of MST4 Underlies a Novel Inhibitory Role of MicroRNA Let-7a in the Progression of Retinoblastoma

Purpose

Retinoblastoma (RB) is the most common intraocular malignancy in children. Deregulation of several microRNAs (miRNAs) has been identified in RB. However, the specific effect of let-7a on RB remains unclear. The present study aims to explore the effect of let-7a on malignant biological behaviors of RB cells and angiogenesis in RB.

Methods

The expressions of let-7a and mammalian sterile-20 like kinase 4 (MST4) in RB were determined with the use of real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis. Next, in order to explore effects of let-7a and MST4 on RB cellular functions, RB cells were transfected with let-7a-mimic, let-7a inhibitor, si-MST4, or co-transfected with let-7a-mimic and oe-MST4 plasmids. Subsequently, the interaction among let-7a, MST4, and the MAPK signaling pathway was evaluated by RT-qPCR, dual-luciferase reporter gene assay, and Western blot analysis. Finally, the effects of let-7a and MST4 were further confirmed in vivo by injecting nude mice with RB cells stably expressing let-7a agomir or sh-MST4.

Results

Rb tissues and cells presented with downregulated Let-7a and upregulated MST4. Let-7a negatively targeted MST4 to block the activation of the MAPK signaling pathway. Upregulation of let-7a promoted apoptosis, and facilitated proliferation, angiogenesis, migration, and invasion of RB cells by decreasing MST4. Elevation of let-7a or silencing MST4 restricted angiogenesis and tumorigenesis in RB mice.

Conclusions

Taken together, let-7a inhibits angiogenesis in RB by silencing MST4 and inhibiting the MAPK signaling pathway.

Development of In Vivo Model of Intraocular Retinoblastoma

Here we describe creation of a model of intraocular retinoblastoma on 4 mature immunodeficient BALB/c nude mice of both sexes. A suspension of the primary retinoblastoma culture was injected into each of the 8 eyes of the test animals. The injections were performed under the control of an operating microscope using insulin syringes with a diameter of 29G transsclerally into the subretinal space in a volume of 0.3 ml at a rate of 10,000 cells in 25 μl physiological saline. The culture of Rb10 cells derived from a patient with retinoblastoma passed 12 passages at the time of the experiments. After 9-week follow-up, a clinical (ophthalmoscopy) and instrumental (ultrasound) study was performed with visualization of the tumor mass on the fundus. After enucleation, a morphological study was performed. The retinoblastoma tumor nodes were identified in two eyes. The proposed model can be used for further research and for testing new chemotherapeutic drugs and treatment regimens for retinoblastoma.

Comparison of the therapeutic effects of lobaplatin and carboplatin on retinoblastoma in vitro and in vivo

Retinoblastoma (RB) is one of the most aggressive malignancies affecting infants and children. Platinum drugs are commonly used in the treatment of RB; however, their efficacy is often compromised by drug resistance and severe toxicity. The present study aimed to investigate and compare the toxicity and antitumor activity of the third-generation platinum drugs, carboplatin and lobaplatin, in vitro and in vivo. The Y79 RB cell line was treated with carboplatin or lobaplatin in vitro and then used to establish xenografts in immunodeficient nude mice in vivo; the effects of pharmacological doses of these drugs were then assessed. High concentrations of carboplatin and lobaplatin markedly inhibited Y79 RB cell proliferation in vitro. In addition, the lobaplatin group exhibited higher proportions of early-stage apoptotic cells than the carboplatin group, while no significant differences in the proportions of cells in the S phase were observed between the 2 groups, as shown by flow cytometry. Significant changes in the E2F1/Cdc25a/Cdk2 pathway in the RB cells were detected by RNA-seq following carboplatin or lobaplatin intervention. RT-qPCR, immunofluorescence and immunohistochemical analyses in vivo and in vitro demonstrated that the trends of drug-induced inhibition of tumor pathological changes may have been regulated through the E2F1/Cdc25a/Cdk2 pathway, and that lobaplatin was more effective than carboplatin in controlling tumors in vivo. On the whole, the findings of the present study demonstrate that lobaplatin is associated with lower cytotoxicity and exerts more prominent therapeutic effects than carboplatin on Y79 RB cells in vitro and in mice in vivo.

Mechanism of HN‑3 cell apoptosis induced by carboplatin: Combination of mitochondrial pathway associated with Ca2+ and the nucleus pathways

Laryngeal carcinomas have been recognized as a serious health threat worldwide. In the present study, the mechanism of apoptosis in HN-3 cells induced by carboplatin (CBCDA), a widely used anti-cancer drug, was investigated. The pro-apoptotic effect of CBCDA in HN-3 cells was demonstrated to be time- and dose-dependent. Therefore, the stages of apoptosis were investigated in chronological order. The results demonstrated that excessive generation of cytosolic Ca²⁺ in HN-3 cells was initially triggered when cells were exposed to CBCDA, followed by the appearance of mitochondrial depolarization and oxidative stress, leading to the release of apoptosis-inducing factor. At later stages, expression of caspase-8 was increased due to the apoptotic signals originating from CBCDA-induced DNA damage, as well as caspase-9 and poly ADP ribose polymerase (PARP) expression upregulation. Glutathione decreased the available CBDCA concentration, decreased apoptosis and alleviating oxidative stress, thus reducing the actual effective concentration. Mechanistic research may benefit the rational design of more efficient therapeutic strategies as well as development of novel platinum-based agents.

Anti-VEGF for ROP and Pediatric Retinal Diseases

Vascular endothelial growth factor (VEGF) is an important mediator of the pathological neovascularization and vascular permeability of the eye. The increasing use of intravitreal therapies targeting VEGF has revolutionized the treatment of pediatric vitreoretinal diseases. In retinopathy of prematurity (ROP), the role of VEGF in pathogenesis has been well recognized and the use of anti-VEGF treatment in phase 2 ROP has demonstrated promising results, particularly in severe cases of posterior disease. This has made VEGF an established target in the treatment of pediatric retinal diseases known to have abnormal vascular activity. However, questions remain about late systemic and neurodevelopmental effects after anti-VEGF therapy for children because intravitreal injection of anti-VEGF may result in systemic circulation of anti-VEGF agent and a corresponding suppression of systemic VEGF. We do not currently know whether the short-term suppression of systemic VEGF affects long-term neurodevelopmental outcomes because VEGF is a vital supporting factor during neurodevelopment. This review article focuses on the evidence for the use of anti-VEGF treatment in certain pediatric ocular diseases, including ROP, Coats disease, and retinoblastoma. More extensive and prospective studies are warranted to further elucidate the role of anti-VEGF therapy in these diseases and illustrate how we can optimally use these agents in pediatric patients.