Publications

Neuroblastoma (NB) is among the most common malignancies in children and represents a therapeutic challenge in pediatric oncology. p53 family proteins play a critical role in protecting cells from genomic instability and malignant transformation. However, in NB, their activities are often inhibited by interacting proteins such as MDM2. The interplay between p53 family pathway and N-Myc, a key biomarker of poor prognosis, is also a critical factor in NB pathogenesis. Herein, we disclose 1-(dibromomethyl)-3,4,6-trimethoxy-9H-xanthen-9-one (LEM3) as a new p53 family-activating agent with potent NB anticancer activity. At 0.13-2.1 mu M, LEM3 inhibited the growth of several NB cell lines. Its activity was further evidenced in spheroids, patient-derived NB cells, and in a vasculature stiffness-based model of MYCN-amplified NB cells. This growth-inhibitory effect was associated with cell cycle arrest and apoptosis, in SH-SY5Y and SK-N-BE(2) NB cells, without apparent acquisition of resistance. LEM3 inhibited cell migration and invasion and reduced the expression of NB-related prognostic markers, particularly MYCN mRNA and protein levels. LEM3 released p53, TAp63, and TAp73 from their interaction with MDM2 both in a yeast-based assay and NB cells; for p53, this led to increased protein stabilization, DNA-binding ability, and transcriptional activity. Fluorescence quenching and docking analyses suggested that LEM3 binds to p53, TAp63, and TAp73 at the MDM2-binding site within their transactivation domain. LEM3 also synergies with doxorubicin and cisplatin in NB cells. Given the central role of the p53 family MDM2-MYCN axis in NB pathogenesis, our findings support LEM3 as a promising compound for advancing NB targeted therapy.

JTD Keywords: Amplification, Cell-lines, Expression, High-risk neuroblastoma, Mdm2, Mutant p53, N-myc, N-myc oncogene, Neuroblastoma, P53 family proteins, P53/mdm2/p14(arf) pathway, P73, Sensitizes neuroblastoma, Targeted anticancer therapy, Xanthone derivative

Steroid myopathy is a clinically challenging condition exacerbated by prolonged corticosteroid use or adrenal tumors. In this study, we engineered a functional three-dimensional (3D) in vitro skeletal muscle model to investigate steroid myopathy. By subjecting our bioengineered muscle tissues to dexamethasone treatment, we reproduced the molecular and functional aspects of this disease. Dexamethasone caused a substantial reduction in muscle force, myotube diameter and induced fatigue. We observed nuclear translocation of the glucocorticoid receptor (GCR) and activation of the ubiquitin-proteasome system within our model, suggesting their coordinated role in muscle atrophy. We then examined the therapeutic potential of taurine in our 3D model for steroid myopathy. Our findings revealed an upregulation of phosphorylated AKT by taurine, effectively countering the hyperactivation of the ubiquitin- proteasomal pathway. Importantly, we demonstrate that discontinuing corticosteroid treatment was insufficient to restore muscle mass and function. Taurine treatment, when administered concurrently with corticosteroids, notably enhanced contractile strength and protein turnover by upregulating the AKT-mTOR axis. Our model not only identifies a promising therapeutic target, but also suggests combinatorial treatment that may benefit individuals undergoing corticosteroid treatment or those diagnosed with adrenal tumors.

JTD Keywords: 3d bioengineered skeletal muscle tissues, Adrenal cortex hormones, Atroph, Colocalization, Corticosteroids, Dexamethasone, Glucocorticoid-receptor, Humans, Mechanisms, Models, biological, Mtor protein, human, Muscle contraction, Muscle fibers, skeletal, Muscle strength, Muscle, skeletal, Muscular diseases, Organ size, Phosphorylation, Proteasome endopeptidase complex, Proto-oncogene proteins c-akt, Receptors, glucocorticoid, Signal transduction, Skeletal-muscle, Steroid myopathy, Steroids, Supplementation, Taurin, Taurine, Tor serine-threonine kinases, Ubiquitin

Background Pilocytic astrocytoma (PA) is the most common pediatric brain tumor and a mitogen-activated protein kinase (MAPK)-driven disease. Oncogenic MAPK-signaling drives the majority of cells into oncogene-induced senescence (OIS). While OIS induces resistance to antiproliferative therapies, it represents a potential vulnerability exploitable by senolytic agents. Methods We established new patient-derived PA cell lines that preserve molecular features of the primary tumors and can be studied in OIS and proliferation depending on expression or repression of the SV40 large T antigen. We determined expression of anti-apoptotic BCL-2 members in these models and primary PA. Dependence of senescent PA cells on anti-apoptotic BCL-2 members was investigated using a comprehensive set of BH3 mimetics. Results Senescent PA cells upregulate BCL-XL upon senescence induction and show dependency on BCL-XL for survival. BH3 mimetics with high affinity for BCL-XL (BCL-XLi) reduce metabolic activity and induce mitochondrial apoptosis in senescent PA cells at nano-molar concentrations. In contrast, BH3 mimetics without BCL-XLi activity, conventional chemotherapy, and MEK inhibitors show no effect. Conclusions Our data demonstrate that BCL-XL is critical for survival of senescent PA tumor cells and provides proof-of-principle for the use of clinically available BCL-XL-dependent senolytics.

JTD Keywords: bcl-xl, bh3 mimetics, oncogene-induced senescence, Bcl-xl, Bh3 mimetics, Expression, Family, Inhibitor, Low-grade glioma, Navitoclax, Oncogene-induced senescence, Pilocytic astrocytoma, Stem-cells

Osteosarcoma is the most common primary bone tumor, and its first line of treatment presents a high failure rate. The 5-year survival for children and teenagers with osteosarcoma is 70% (if diagnosed before it has metastasized) or 20% (if spread at the time of diagnosis), stressing the need for novel therapies. Recently, cold atmospheric plasmas (ionized gases consisting of UV-Vis radiation, electromagnetic fields and a great variety of reactive species) and plasma-treated liquids have been shown to have the potential to selectively eliminate cancer cells in different tumors through an oxidative stress-dependent mechanism. In this work, we review the current state of the art in cold plasma therapy for osteosarcoma. Specifically, we emphasize the mechanisms unveiled thus far regarding the action of plasmas on osteosarcoma. Finally, we review current and potential future approaches, emphasizing the most critical challenges for the development of osteosarcoma therapies based on this emerging technique.

JTD Keywords: cancer stem cells, cold atmospheric plasma, osteosarcoma, oxidative stress, plasma treated liquids, reactive oxygen and nitrogen species, Antineoplastic activity, Antineoplastic agent, Cancer chemotherapy, Cancer stem cell, Cancer stem cells, Cancer surgery, Cancer survival, Cell therapy, Cold atmospheric plasma, Cold atmospheric plasma therapy, Electromagnetism, Human, In vitro study, Intracellular signaling, Oncogene, Osteosarcoma, Oxidative stress, Plasma treated liquids, Reactive nitrogen species, Reactive oxygen and nitrogen species, Reactive oxygen metabolite, Review, Tumor microenvironment