Analysis of ADAM9 regulation and function in vestibular schwannoma primary cells

Single-cell RNA sequencing reveals ECM remodeling-tumor stiffness-FAK as a key driver of vestibular schwannoma progression

Vestibular schwannoma (VS), characterized by the absence of merlin expression, is the most prevalent benign tumor located at the cerebellopontine angle, lacking approved pharmaceutical interventions except for off-label utilization of bevacizumab. The role of Tumor stiffness-Focal adhesion kinase (FAK) activation in fueling tumor progression is well-established, with merlin deficiency serving as a biomarker for tumor sensitivity to FAK inhibitors. In this context, we investigated whether Tumor stiffness-FAK contributes to VS progression. Single-cell RNA sequencing revealed associations between VS progression and gene sets related to "Response to mechanical stimulus" and "Neurotrophin signaling pathway". Histological studies indicated a potential involvement of neurotrophins in early stages of VS tumorigenesis, while enhanced Extracellular matrix (ECM) remodeling-Tumor stiffness-FAK signaling accompanies later stages of VS progression. In vitro experiments demonstrated that elevated matrix stiffness induces cytoskeletal remodeling, cell proliferation, and metalloproteinase expression in VS cells by activating FAK. Conversely, FAK inhibition diminishes these effects. Collectively, this study suggests that ECM remodeling-Tumor stiffness contributes to VS progression via FAK activation, positioning FAK as a promising therapeutic target in treating VS.

Metastasis Associated in Colorectal Cancer 1 (MACC1) mRNA Expression Is Enhanced in Sporadic Vestibular Schwannoma and Correlates to Deafness

Vestibular schwannoma (VS) are benign cranial nerve sheath tumors of the vestibulocochlear nerve. Their incidence is mostly sporadic, but they can also be associated with NF2-related schwannomatosis (NF2), a hereditary tumor syndrome. Metastasis associated in colon cancer 1 (MACC1) is known to contribute to angiogenesis, cell growth, invasiveness, cell motility and metastasis of solid malignant cancers. In addition, MACC1 may be associated with nonsyndromic hearing impairment. Therefore, we evaluated whether MACC1 may be involved in the pathogenesis of VS. Sporadic VS, recurrent sporadic VS, NF2-associated VS, recurrent NF2-associated VS and healthy vestibular nerves were analyzed for MACC1 mRNA and protein expression by quantitative polymerase chain reaction and immunohistochemistry. MACC1 expression levels were correlated with the patients' clinical course and symptoms. MACC1 mRNA expression was significantly higher in sporadic VS compared to NF2-associated VS (p < 0.001). The latter expressed similar MACC1 concentrations as healthy vestibular nerves. Recurrent tumors resembled the MACC1 expression of the primary tumors. MACC1 mRNA expression was significantly correlated with deafness in sporadic VS patients (p = 0.034). Therefore, MACC1 might be a new molecular marker involved in VS pathogenesis.

Understanding the Molecular Mechanism of Vestibular Schwannoma for Hearing Preservation Surgery: Otologists’ Perspective from Bedside to Bench

Vestibular schwannoma is a clinically benign schwannoma that arises from the vestibulocochlear nerve that causes sensorineural hearing loss. This tumor is clinically and oncologically regarded as a benign tumor as it does not metastasize or invade surrounding tissues. Despite being a benign tumor, its management is difficult and controversial due to the potential serious complications, such as irreversible sensorineural hearing loss, of current interventions. Therefore, preventing hearing loss due to the natural course of the disease and complications of surgery is a challenging issue for an otologist. Improvements have been reported recently in the treatment of vestibular schwannomas. These include advances in intraoperative monitoring systems for vestibular schwannoma surgery where the risk of hearing loss as a complication is decreased. Precise genomic analysis of the tumor would be helpful in determining the characteristics of the tumor for each patient, leading to a better hearing prognosis. These procedures are expected to help improve the treatment of vestibular schwannomas. This review summarizes recent advances in vestibular schwannoma management and treatment, especially in hearing preservation. In addition, recent advances in the understanding of the molecular mechanisms underlying vestibular schwannomas and how these advances can be applied in clinical practice are outlined and discussed, respectively. Moreover, the future directions from the bedside to the bench side are presented from the perspective of otologists.

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.