Search Results (7)

Background/Objectives: NF2-related schwannomatosis (NF2-SWN) is a genetic tumor predisposition syndrome of the nervous system caused by pathogenic variants in NF2 encoding the merlin tumor suppressor. Truncating variants in NF2 cause severe phenotypes with higher tumor burden, early mortality, and a lifetime need for multiple surgeries due to lack of medications that control schwannoma growth. Methods: We developed a functional precision medicine (FPM)-inspired workflow to identify drug sensitivities in cells isolated from a pediatric severe NF2-SWN patient’s spinal and peripheral schwannomas. Transcriptomic profiling, high-content drug sensitivity assays, tissue and isolated cell immunostaining, flow cytometry, and capillary-based immunoblotting were used to study the available tissues. Results: Aberrant merlin-dependent pathway expression was conserved between the spinal schwannoma and its cultured primary cells. Drug sensitivity screens in 2- and 3-dimensional formats revealed cytotoxic effects of fimepinostat in primary cells; dasatinib with brigatinib was the most effective cytostatic combination. Ineffective therapies attempted in the patient were also ineffective ex vivo. Conclusions: These data support the idea of using the FPM workflow to improve and individualize the standard of care for severe NF2-SWN patients using surgical samples. Full article

There is no approved drug therapy for schwannomas associated with NF2-related schwannomatosis (NF2-SWN). Neither life-saving surgical resection or radiation are curative and can compound the debilitating neurological effects of the schwannomas. We previously identified fimepinostat, a dual histone deacetylase (HDAC)/phosphoinositide-3 kinase (PI3K) inhibitor, as a promising drug candidate with pro-apoptotic effects on NF2-related schwannomas. This preclinical study used the pharmaceutical formulation of fimepinostat to confirm its efficacy in schwannomas and identify pro-apoptotic signaling pathways. Fimepinostat was tested in human schwannoma model cells, patient-derived primary vestibular and non-vestibular schwannoma cells, and in a sciatic nerve allograft model. The signaling pathways leading to caspase-3-dependent apoptosis were elucidated using immune assays, flow cytometry, imaging, proteome, and acetylome analysis. Acute exposure to fimepinostat led to p21-dependent cell cycle inhibition, upregulation of tumor necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAIL R2), and downregulation of tumor necrosis factor receptor 1 (TNFR1), Yes-associated protein (YAP), and inhibitors of apoptosis. Moreover, fimepinostat downregulated cytokine and chemokine secretion increased by merlin loss in schwannoma cells. Fimepinostat is a promising new drug intervention for NF2-SWN patients with the potential to promote tumor regression. Full article

Background/Objectives: Neurofibromatosis Type 1 (NF1) is a genetic syndrome caused by pathogenic NF1 variants encoding neurofibromin, a Ras GTPase activating protein. Individuals with NF1 develop peripheral nerve sheath tumors called neurofibromas. Approximately 50% of NF1 patients develop plexiform neurofibromas (pNFs) which have up to 13% lifetime risk of transformation into malignant peripheral nerve sheath tumors (MPNSTs). Current therapeutic strategies emphasize surgical resection with wide margins, radiation, and traditional chemotherapy for unresectable MPNSTs. However, NF1 patients diagnosed with MPNSTs have 5-year survival rates as low as 16%. The two recently FDA-approved drugs for pNFs, the MEK inhibitors selumetinib and mirdametinib, are not used to prevent or treat MPNSTs. Methods: The MEK inhibitor trametinib and the dual HDAC/PI3K inhibitor fimepinostat were assessed for growth inhibitory effects in nine unique patient-derived MPNST cell lines, as both drugs have preclinical efficacy in other Schwann cell-derived tumors. Results: Trametinib, which is approved for malignant melanomas, promoted cell death in 7/9 MPNST cell lines with a geometric mean GI50 = 17 nM. When directly compared to selumetinib and mirdametinib in a subset of four MPNST cell lines, trametinib had the lowest mean GI50 (trametinib = 38 nM, mirdametinib = 1.6 µM, selumetinib = 4.9 µM). Trametinib was also superior to selumetinib and mirdametinib in blocking ERK1/2 phosphorylation for 24 h. Fimepinostat promoted cell death in all cell lines with a geometric mean GI50 = 17 pM. Conclusions: These studies demonstrate in vitro efficacy for two candidate MPNST therapeutics which could reduce tumor burden and metastasis in NF1 patients. Full article

Phosphatidylinositol-3-kinases (PI3Ks) constitute an important validated therapeutic class involved in crucial cellular processes, and their dysregulation is associated with cancer initiation and progression. Nonetheless, intrinsic and acquired resistance mechanisms associated with PI3K pathway modulation have underscored the need for alternative therapeutic strategies. In this context, recent studies have shown that simultaneous inhibition of PI3K and histone deacetylases (HDAC) promotes synergistic antitumor effects in different cancer cell lines. HDACs are validated epigenetic targets that are extensively explored in clinical practice and have a pharmacophore with versatility for structural modifications, which facilitates the design of multitarget inhibitors. This review examines the rational design and synthetic evolution of dual PI3K/HDAC inhibitors, an area catalyzed by the development of fimepinostat, the first clinically evaluated agent exhibiting potent and balanced inhibition of both targets. We provide a critical overview of PI3K/HDAC multitarget inhibitors reported in recent years that have progressed to preclinical or clinical investigation, discussing the structural frameworks employed, medicinal chemistry strategies adopted, and structure–activity relationships established. Particular attention is given to advantageous molecular features as well as challenges related to toxicity, pharmacokinetic behavior, and pharmacodynamic modulation. From this comprehensive analysis, we outline key considerations and emerging design principles that may inform the next generation of PI3K/HDAC multitarget drug candidates. Insights derived from the diversity of chemical scaffolds, activity profiles, and selectivity patterns described herein may support the development of innovative therapeutic agents capable of overcoming current limitations in anticancer treatment. Full article

Objectives: Pleural mesothelioma (PM) is a rare cancer that often develops after a decades-long latency period and confers a grim prognosis. Novel, biomarker-based therapeutic modalities are expected to improve the outcome of patients with advanced PM. CUDC-907 (fimepinostat) is a dual inhibitor that affects both histone deacetylases and PI3K enzymes. Its antitumor activity was described in several cancer types, but it has not yet been explored in PM. Materials and Methods: The sensitivity of 22 PM cell lines—including 18 models established in our laboratory—to cisplatin and CUDC-907 was determined using a cell viability assay. BAP1, PTEN, and c-Myc expression, as well as MYC copy number variation, were measured. The effect of combination treatment with cisplatin was assessed with cell viability, cell cycle, and 3D spheroid formation assays. Results: Most PM cell lines were sensitive to CUDC-907 treatment, and the CUDC-907 response was significantly higher in cell lines with higher c-Myc expression due to MYC copy number gain or amplification. Importantly, all cisplatin-insensitive cell lines were sensitive to CUDC-907. Combination treatment with cisplatin synergistically decreased cell viability and induced G2/M arrest or cell death. We tested cisplatin-sensitive P31WT and cisplatin resistant P31cis isogeneic pair and found that in both 2D and 3D assays the cisplatin-resistant cells showed a higher sensitivity to CUDC-907 single treatment. Combining CUDC-907 with cisplatin further decreased cell growth even in cisplatin-resistant cells. Conclusions: The majority of PM cell models are sensitive to CUDC-907, which may be a potent therapeutic agent in PM. Full article

Schistosomiasis is one of the most important neglected tropical diseases. Until an effective vaccine is registered for use, the cornerstone of schistosomiasis control remains chemotherapy with praziquantel. The sustainability of this strategy is at substantial risk due to the possibility of praziquantel insensitive/resistant schistosomes developing. Considerable time and effort could be saved in the schistosome drug discovery pipeline if available functional genomics, bioinformatics, cheminformatics and phenotypic resources are systematically leveraged. Our approach, described here, outlines how schistosome-specific resources/methodologies, coupled to the open-access drug discovery database ChEMBL, can be cooperatively used to accelerate early-stage, schistosome drug discovery efforts. Our process identified seven compounds (fimepinostat, trichostatin A, NVP-BEP800, luminespib, epoxomicin, CGP60474 and staurosporine) with ex vivo anti-schistosomula potencies in the sub-micromolar range. Three of those compounds (epoxomicin, CGP60474 and staurosporine) also demonstrated potent and fast-acting ex vivo effects on adult schistosomes and completely inhibited egg production. ChEMBL toxicity data were also leveraged to provide further support for progressing CGP60474 (as well as luminespib and TAE684) as a novel anti-schistosomal compound. As very few compounds are currently at the advanced stages of the anti-schistosomal pipeline, our approaches highlight a strategy by which new chemical matter can be identified and quickly progressed through preclinical development. Full article

The dysregulation of PI3K, HDACs, and MYCN are well known for promoting multiple cancer types, including neuroblastoma (NB). Targeting the upstream regulators of MYCN, including HDACs and PI3K, was shown to suppress cancer growth. In the present study, we analyze different NB patient datasets to reveal that high PI3K and HDAC expression is correlated with overall poor NB patient survival. High PI3K level is also found to be associated with high MYCN level and NB stage progression. We repurpose a dual inhibitor CUDC-907 as a single agent to directly target both PI3K and HDAC in NB. We use in vitro methodologies to determine the efficacy and selectivity of CUDC-907 using six NB and three control fibroblast cell lines. Our results show that CUDC-907 significantly inhibits NB proliferation and colony growth, induces apoptosis, blocks cell cycle progression, inhibits MYCN, and enhances H3K9Ac levels by inhibiting the PI3K/AKT signaling pathway and HDAC function. Furthermore, CUDC-907 significantly inhibits NB tumor growth in a 3D spheroid tumor model that recapitulates the in vivo tumor growth. Overall, our findings highlight that the dual inhibition of PI3K and HDAC by CUDC-907 is an effective therapeutic strategy for NB and other MYC-dependent cancers. Full article