A proteasome-resistant fragment of NIK mediates oncogenic NF-κB signaling in schwannomas

Tumors of the nervous system and hearing loss: Beyond vestibular schwannomas

Hearing loss is a common side effect of many tumor treatments. However, hearing loss can also occur as a direct result of certain tumors of the nervous system, the most common of which are the vestibular schwannomas (VS). These tumors arise from Schwann cells of the vestibulocochlear nerve and their main cause is the loss of function of NF2, with 95 % of cases being sporadic and 5 % being part of the rare neurofibromatosis type 2 (NF2)-related Schwannomatosis. Genetic variations in NF2 do not fully explain the clinical heterogeneity of VS, and interactions between Schwann cells and their microenvironment appear to be critical for tumor development. Preclinical in vitro and in vivo models of VS are needed to develop prognostic biomarkers and targeted therapies. In addition to VS, other tumors can affect hearing. Meningiomas and other masses in the cerebellopontine angle can compress the vestibulocochlear nerve due to their anatomic proximity. Gliomas can disrupt several neurological functions, including hearing; in fact, glioblastoma multiforme, the most aggressive subtype, may exhibit early symptoms of auditory alterations. Besides, treatments for high-grade tumors, including chemotherapy or radiotherapy, as well as incomplete resections, can induce long-term auditory dysfunction. Because hearing loss can have an irreversible and dramatic impact on quality of life, it should be considered in the clinical management plan of patients with tumors, and monitored throughout the course of the disease.

From bench to bedside: Advancing towards therapeutic treatment of vestibular schwannomas

Vestibular schwannomas are rare intracranial tumors originating from Schwann cells of the vestibular nerve. Despite their benign nature, these tumors can exert significant mass effects and debilitating symptoms, including gradual hearing loss, vertigo, facial nerve dysfunction, and headaches. Current clinical management options encompass wait-and-scan, surgery, radiation therapy, and off-label medication. However, each approach exhibits its own challenges and harbors limitations that underscore the urgent need for therapeutic treatments. Over the past 2 decades, extensive elucidation of the molecular underpinnings of vestibular schwannomas has unraveled genetic anomalies, dysregulated signaling pathways, downstream of receptor tyrosine kinases, disrupted extracellular matrix, inflammatory tumor microenvironment, and altered cerebrospinal fluid composition as integral factors in driving the development and progression of the disease. Armed with this knowledge, novel therapeutic interventions tailored to the unique molecular characteristics of those conditions are actively being pursued. This review underscores the urgency of addressing the dearth of Food and Drug Administration-approved drugs for vestibular schwannoma, highlighting the key molecular discoveries and their potential translation into therapeutics. It provides an in-depth exploration of the evolving landscape of therapeutic development, which is currently advancing from bench to bedside. These ongoing efforts hold the promise of significantly transforming the lives of vestibular schwannoma patients in the future.

Drug Repositioning for Refractory Benign Tumors of the Central Nervous System

Drug repositioning (DR) is the process of identifying novel therapeutic potentials for already-approved drugs and discovering new therapies for untreated diseases. DR can play an important role in optimizing the pre-clinical process of developing novel drugs by saving time and cost compared with the process of de novo drug discovery. Although the number of publications related to DR has rapidly increased, most therapeutic approaches were reported for malignant tumors. Surgical resection represents the definitive treatment for benign tumors of the central nervous system (BTCNS). However, treatment options remain limited for surgery-, chemotherapy- and radiation-refractory BTCNS, as well as malignant tumors. Meningioma, pituitary neuroendocrine tumor (PitNET), and schwannoma are the most common BTCNS. The treatment strategy using DR may be applied for refractory BTCNS, such as Grade 2 meningiomas, neurofibromatosis type 2-related schwannomatosis, and PitNETs with cavernous sinus invasion. In the setting of BTCNS, stable disease can provide significant benefit to the patient. DR may provide a longer duration of survival without disease progression for patients with refractory BTCNS. This article reviews the utility of DR for refractory BTCNS.

β 2 -Microglobulin Participates in the Development of Vestibular Schwannoma by Regulating Nuclear Factor-κB

BACKGROUND AND OBJECTIVES

Vestibular schwannoma (VS), the most common intercranial schwannoma, originates from the sheath of the vestibular nerve. The growth rate of VS varies greatly, with the tumor enlarging gradually, which can compress the peripheral nerve tissue and reveal corresponding symptoms. This study was aimed to elucidate the growth mechanism of VS by analyzing cellular changes at protein, messenger ribonucleic acid (mRNA), and other molecular levels.

METHODS

We determined mRNA and protein levels of β 2 -microglobulin (β 2 -M) and nuclear factor κB (NF-κB) in tumors of different sizes using the real-time polymerase chain reaction and Western blotting, respectively. The relationship between these factors was verified in VS primary cells cultured in vitro, and the potential role of β 2 -M and NF-κB in VS growth was elucidated.

RESULTS

In the secretions of freshly isolated tumor tissue cultured for 72 h, the concentration of β 2 -M was positively correlated with the tumor diameter. Furthermore, tumors with larger diameter showed higher expressions of β 2 -M and NF-κB at protein and mRNA level. β 2 -M treatment resulted in elevated protein expression of NF-κB and also its phosphorylated form in vitro.

CONCLUSION

β 2 -M may participate in VS growth by regulating NF-κB and act as a key regulatory molecule in VS tumor growth.

Potential Molecular Biomarkers of Vestibular Schwannoma Growth: Progress and Prospects

Vestibular schwannomas (VSs, also known as acoustic neuromas) are relatively rare benign brain tumors stem from the Schwann cells of the eighth cranial nerve. Tumor growth is the paramount factor for neurosurgeons to decide whether to choose aggressive treatment approach or careful follow-up with regular magnetic resonance imaging (MRI), as surgery and radiation can introduce significant trauma and affect neurological function, while tumor enlargement during long-term follow-up will compress the adjacent nerves and tissues, causing progressive hearing loss, tinnitus and vertigo. Recently, with the deepening research of VS biology, some proteins that regulate merlin conformation changes, inflammatory cytokines, miRNAs, tissue proteins and cerebrospinal fluid (CSF) components have been proposed to be closely related to tumor volume increase. In this review, we discuss advances in the study of biomarkers that associated with VS growth, providing a reference for exploring the growth course of VS and determining the optimal treatment strategy for each patient.

A Review of Drug Therapy in Vestibular Schwannoma

Vestibular schwannomas (VSs, also known as acoustic neuromas) are benign intracranial tumors commonly managed with observation, surgery, and radiotherapy. There is currently no approved pharmacotherapy for VS patients, which is why we conducted a detailed search of relevant literature from PubMed and Web of Science to explore recent advances and experiences in drug therapy. VSs feature a long course of disease that requires treatment to have minimal long-term side effects. Conventional chemotherapeutic agents are characterized by neurotoxicity or ototoxicity, poor effect on slow-growing tumors, and may induce new mutations in patients who have lost tumor suppressor function, and therefore are unsuitable for treating VSs. Along with the well-investigated molecular pathophysiology of VS and the increasingly accessible technology such as drug repositioning platform, many molecular targeted inhibitors have been identified and shown certain therapeutic effects in preclinical experiments or clinical trials.

NIK as a Druggable Mediator of Tissue Injury

NF-κB-inducing kinase (NIK, MAP3K14) is best known as the apical kinase that triggers non-canonical NF-κB activation and by its role in the immune system. Recent data indicate a role for NIK expressed by non-lymphoid cells in cancer, kidney disease, liver injury, glucose homeostasis, osteosarcopenia, vascular calcification, hematopoiesis, and endothelial function. The spectrum of NIK-associated disease now ranges from immunodeficiency (when NIK is defective) to autoimmunity, cancer, sterile inflammation, fibrosis, and metabolic disease when NIK is overactive. The development of novel small-molecule NIK inhibitors has paved the way to test NIK targeting to treat disease in vivo, and may eventually lead to NIK targeting in the clinic. In addition, NIK activators are being explored for specific conditions such as myeloid leukemia.