Small-molecule screen identifies modulators of EWS/FLI1 target gene expression and cell survival in Ewing's sarcoma.

Ewing's sarcoma family of tumors (EFT) is characterized by the presence of chromosomal translocations leading to the expression of oncogenic transcription factors such as, in the majority of cases, EWS/FLI1. Because of its key role in Ewing's sarcoma development and maintenance, EWS/FLI1 represents an attractive therapeutic target. Here, we characterize PHLDA1 as a novel direct target gene whose expression is repressed by EWS/FLI1. Using this gene and additional specific well-characterized target genes such as NROB1, NKX2.2 and CAV1, all activated by EWS/FLI1, as a read-out system, we screened a small-molecule compound library enriched for FDA-approved drugs that modulated the expression of EWS/FLI1 target genes. Among a hit-list of nine well-known drugs such as camptothecin, fenretinide, etoposide and doxorubicin, we also identified the kinase inhibitor midostaurin (PKC412). Subsequent experiments demonstrated that midostaurin is able to induce apoptosis in a panel of six Ewing's sarcoma cell lines in vitro and can significantly suppress xenograft tumor growth in vivo. These results suggest that midostaurin might be a novel drug that is active against Ewing's cells, which might act by modulating the expression of EWS/FLI1 target genes.

Hypothetical Switch of Anti-Vascular Endothelial Growth Factor in Neovascular Age-Related Macular Degeneration: An ARIES Post Hoc Analysis.

INTRODUCTION: Switching to an alternative anti-vascular endothelial growth factor (anti-VEGF) agent has been suggested for patients with neovascular age-related macular degeneration (nAMD) who have a suboptimal response to initial therapy. However, post hoc analyses of some studies have shown that continuation of initial anti-VEGF therapy is, in many cases, associated with stable visual outcomes or gradual gains. METHODS: This ARIES (ClinicalTrials.gov Identifier: NCT02581891) post hoc analysis describes outcomes in patients with treatment-naïve nAMD receiving treat-and-extend intravitreal aflibercept (IVT-AFL) for 104 weeks, who were identified as meeting criteria for an early hypothetical switch. Patients were categorized retrospectively according to six criteria (presence of central intraretinal and/or subretinal fluid at week 8 or 24, with/without a next planned treatment interval ≤ 8 weeks, and with/without gains in best-corrected visual acuity [BCVA] ≤ 5 letters [with absolute BCVA < 70 letters]). RESULTS: Hypothetical switch criteria were largely met due to the presence of central subretinal fluid rather than intraretinal fluid. Depending on the criterion, 8-46% of patients were considered to be hypothetical switchers. BCVA outcomes were not worse in the hypothetical switchers, irrespective of criteria. Using criteria of intraretinal/subretinal fluid at week 24 and a next planned treatment interval ≤ 8 weeks, mean changes in BCVA (letters) from baseline in hypothetical switchers and non-switchers were: + 6.1 (95% confidence interval [CI] 3.4, 8.8) and + 6.6 (95% CI 4.7, 8.6), respectively, at week 24; + 8.2 (95% CI 5.0, 11.3) and + 7.5 (95% CI 5.3, 9.7), respectively, at week 52; and + 5.7 (95% CI 1.3, 10.1) and + 3.4 (95% CI 0.1, 6.7), respectively, at week 104. CONCLUSIONS: In newly diagnosed nAMD, there appears little rationale for early switching from IVT-AFL since, with continuous proactive treatment, comparable visual gains can be achieved by patients meeting hypothetical switch criteria compared with those who initially respond well on a treat-and-extend regimen. However, further prospective studies are needed. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02581891. Video summary of the ARIES Post Hoc Analysis "Hypothetical Switch of Anti-Vascular Endothelial Growth Factor in Neovascular Age-Related Macular Degeneration" (MP4 54283 KB).

Two-year outcomes of intravitreal aflibercept in a Swiss routine treat and extend regimen for patients with neovascular age-related macular degeneration.

The aim of this observational study was to assess the use and outcome of intravitreal aflibercept in a treat and extend regimen in treatment-naïve neovascular AMD patients in routine practice. This both retrospective and prospective study was conducted in four larger Swiss retina clinics (ASTERIA study). The primary endpoint was the mean change in best-corrected visual acuity (BCVA) in ETDRS letters from baseline to 12 months. Between December 2017 and August 2018, 160 patients were included. For patients with available data, the mean change in BCVA was + 8.4 (± 14.4) letters at month 12 (n = 139) and + 5.0 (± 11.4) letters at month 24 (n = 95). A mean number of 8.3 (± 2.4) injections were administered within the first year and 5.4 (± 2.9) injections during the second year. On average, the observed treatment interval at month 12 was 63.3 (± 22.0) days and increased to 69.1 (± 28.6) days at month 24. For 37% of the patients, a treatment interval ≥ 12 weeks was attained at month 24. In conclusion,  intravitreal aflibercept in a Swiss real-life treat and extend regimen resulted in comparable anatomic and functional outcomes as were observed in the prospective registration trials of aflibercept for nAMD treatment.

Cannabinoid receptor ligands as potential anticancer agents--high hopes for new therapies?

OBJECTIVES: The endocannabinoid system is an endogenous lipid signalling network comprising arachidonic-acid-derived ligands, cannabinoid (CB) receptors, transporters and endocannabinoid degrading enzymes. The CB(1) receptor is predominantly expressed in neurons but is also co-expressed with the CB(2) receptor in peripheral tissues. In recent years, CB receptor ligands, including Delta(9)-tetrahydrocannabinol, have been proposed as potential anticancer agents. KEY FINDINGS: This review critically discusses the pharmacology of CB receptor activation as a novel therapeutic anticancer strategy in terms of ligand selectivity, tissue specificity and potency. Intriguingly, antitumour effects mediated by cannabinoids are not confined to inhibition of cancer cell proliferation; cannabinoids also reduce angiogenesis, cell migration and metastasis, inhibit carcinogenesis and attenuate inflammatory processes. In the last decade several new selective CB(1) and CB(2) receptor agents have been described, but most studies in the area of cancer research have used non-selective CB ligands. Moreover, many of these ligands exert prominent CB receptor-independent pharmacological effects, such as activation of the G-protein-coupled receptor GPR55, peroxisome proliferator-activated receptor gamma and the transient receptor potential vanilloid channels. SUMMARY: The role of the endocannabinoid system in tumourigenesis is still poorly understood and the molecular mechanisms of cannabinoid anticancer action need to be elucidated. The development of CB(2)-selective anticancer agents could be advantageous in light of the unwanted central effects exerted by CB(1) receptor ligands. Probably the most interesting question is whether cannabinoids could be useful in chemoprevention or in combination with established chemotherapeutic agents.

CD133 positive embryonal rhabdomyosarcoma stem-like cell population is enriched in rhabdospheres.

Cancer stem cells (CSCs) have been identified in a number of solid tumors, but not yet in rhabdomyosarcoma (RMS), the most frequently occurring soft tissue tumor in childhood. Hence, the aim of this study was to identify and characterize a CSC population in RMS using a functional approach. We found that embryonal rhabdomyosarcoma (eRMS) cell lines can form rhabdomyosarcoma spheres (short rhabdospheres) in stem cell medium containing defined growth factors over several passages. Using an orthotopic xenograft model, we demonstrate that a 100 fold less sphere cells result in faster tumor growth compared to the adherent population suggesting that CSCs were enriched in the sphere population. Furthermore, stem cell genes such as oct4, nanog, c-myc, pax3 and sox2 are significantly upregulated in rhabdospheres which can be differentiated into multiple lineages such as adipocytes, myocytes and neuronal cells. Surprisingly, gene expression profiles indicate that rhabdospheres show more similarities with neuronal than with hematopoietic or mesenchymal stem cells. Analysis of these profiles identified the known CSC marker CD133 as one of the genes upregulated in rhabdospheres, both on RNA and protein levels. CD133(+) sorted cells were subsequently shown to be more tumorigenic and more resistant to commonly used chemotherapeutics. Using a tissue microarray (TMA) of eRMS patients, we found that high expression of CD133 correlates with poor overall survival. Hence, CD133 could be a prognostic marker for eRMS. These experiments indicate that a CD133(+) CSC population can be enriched from eRMS which might help to develop novel targeted therapies against this pediatric tumor.

Cannabinoid receptor 1 is a potential drug target for treatment of translocation-positive rhabdomyosarcoma.

Gene expression profiling has revealed that the gene coding for cannabinoid receptor 1 (CB1) is highly up-regulated in rhabdomyosarcoma biopsies bearing the typical chromosomal translocations PAX3/FKHR or PAX7/FKHR. Because cannabinoid receptor agonists are capable of reducing proliferation and inducing apoptosis in diverse cancer cells such as glioma, breast cancer, and melanoma, we evaluated whether CB1 is a potential drug target in rhabdomyosarcoma. Our study shows that treatment with the cannabinoid receptor agonists HU210 and Delta(9)-tetrahydrocannabinol lowers the viability of translocation-positive rhabdomyosarcoma cells through the induction of apoptosis. This effect relies on inhibition of AKT signaling and induction of the stress-associated transcription factor p8 because small interfering RNA-mediated down-regulation of p8 rescued cell viability upon cannabinoid treatment. Finally, treatment of xenografts with HU210 led to a significant suppression of tumor growth in vivo. These results support the notion that cannabinoid receptor agonists could represent a novel targeted approach for treatment of translocation-positive rhabdomyosarcoma.