Schwannoma Cells Research Articles

BIOM-65. ELEVATED MMP9 EXPRESSION IN ADHERENT AND LARGE VESTIBULAR SCHWANNOMAS: A PROMISING THERAPEUTIC TARGET

Abstract Vestibular schwannoma (VS) is the most common tumor of the cerebellopontine angle affecting up to 1 in 2000 adults and presents significant treatment challenges, especially when the tumor is adherent to the brainstem and cranial nerves. These tumors often require complex surgeries with high risks of complications such as hearing loss, facial paralysis, and incomplete tumor resection. Previous studies have linked immune cell infiltration and protease activation to aggressive VS. MMP9, a protease involved in extracellular matrix (ECM) remodeling, is associated with cancer invasion and progression, suggesting its potential as a biomarker and therapeutic target. This study explores whether MMP9 can classify VS and improve surgical outcomes. METHODS Fresh tumors were collected from patients undergoing surgery to establish primary VS cultures. Transcriptomic profiling was performed to examine expression of genes related to ECM remodeling, protease activation, and immune cell infiltration. MMP9 expression during schwannoma progression was validated using immunofluorescence staining and ELISA. Transwell invasion assays were performed to evaluate the role of MMP9 in schwannoma invasion. The efficacy of small molecule inhibitors against eIF4F (a transcription factor that binds to 5’ UTR of MMP9) and against MMP9 was tested in a mouse model of schwannoma. RESULTS MMP9 was the most abundantly expressed protease in VS. MMP9 expression increased with tumor size, and was higher in adherent than non-adherent VS (49.7 vs. 13.8 ng/mL, p=0.014). MMP9 expression was abundant in perivascular regions in adherent VS. Inhibition of eIF4F reduced schwannoma cell invasion mediated by MMP9.MMP9 inhibition in vivo- reduced tumor burden by 50% in mice. CONCLUSIONS MMP9 is a highly active protease in VS growth and adherent VS. Developing MMP9-targeted therapies could be a breakthrough in managing these challenging tumors.

Synergistic effects of combined BET and FAK inhibition against Vestibular Schwannomas in NF2-related Schwannomatosis.

Neurofibromatosis type 2 (NF2) is a rare disorder that causes vestibular schwannomas (VS), meningiomas and ependymomas. To date, there is no FDA approved drug-based treatment for NF2. We have previously identified that BET inhibition can selectively reduce growth of the NF2-null schwannoma and Schwann cells in vitro and tumorigenesis in vivo and, separately, reported that inhibition of Focal Adhesion Kinase 1 (FAK1) via crizotinib has antiproliferative effects in NF2-null Schwann cells. The current study was aimed at determining whether combined BET and FAK inhibition can synergize and to identify the mechanisms of action. A panel of normal and NF2-null Schwann and schwannoma cell lines were used to characterize the effects of combined BET and FAK inhibition in vitro and in vivo using pharmacological and genetic approaches. The mechanism of action was explored by chromatin immunoprecipitation, ChIP-PCR, western blotting, and functional approaches. We find that combined BET and FAK inhibition are synergistic and inhibit the proliferation of NF2-null schwannoma and Schwann cell lines in vitro and in vivo, by arresting cells in the G1/S and G2/M phases of the cell cycle. Further, we identify the mechanism of action through the downregulation of FAK1 transcription by BET inhibition, which potentiates inhibition of FAK by 100-fold. Our findings suggest that combined targeting of BET and FAK1 may offer a potential therapeutic option for the treatment of NF2-related schwannomas.

Targeting MERTK on tumour cells and macrophages: a potential intervention for sporadic and NF2-related meningioma and schwannoma tumours

Meningioma and schwannoma are common tumours of the nervous system. They occur sporadically or as part of the hereditary NF2-related schwannomatosis syndrome. There is an unmet need for new effective drug treatments for both tumour types. In this paper, we demonstrate overexpression/activation of TAM (TYRO3/AXL/MERTK) receptors (TAMs) and overexpression/release of ligand GAS6 in patient-derived meningioma tumour cells and tissue. For the first time, we reveal the formation of MERTK/TYRO3 heterocomplexes in meningioma and schwannoma tissue. We demonstrate the dependence of AXL and TYRO3 expression on MERTK in both tumour types, as well as interdependency of MERTK and AXL expression in meningioma. We show that MERTK and AXL contribute to increased proliferation and survival of meningioma and schwannoma cells, which we inhibited in vitro using the MERTK/FLT3 inhibitor UNC2025 and the AXL inhibitor BGB324. UNC2025 was effective in both tumour types with superior efficacy over BGB324. Finally, we found that TAMs are expressed by tumour-associated macrophages in meningioma and schwannoma tumours and that UNC2025 strongly depleted macrophages in both tumour types.

Synergistic effect of PAK and Hippo pathway inhibitor combination in NF2-deficient Schwannoma.

Neurofibromatosis type 2 is a genetic disorder that results in the formation and progressive growth of schwannomas, ependymomas, and/or meningiomas. The NF2 gene encodes the Merlin protein, which links cell cortical elements to the actin cytoskeleton and regulates a number of key enzymes including Group I p21-activated kinases (PAKs), the Hippo-pathway kinase LATS, and mTORC. While PAK1 and PAK2 directly bind Merlin and transmit proliferation and survival signals when Merlin is mutated or absent, inhibition of Group 1 PAKs alone has not proven sufficient to completely stop the growth of NF2-deficient meningiomas or schwannomas in vivo, suggesting the need for a second pathway inhibitor. As the Hippo pathway is also activated in NF2-deficient cells, several inhibitors of the Hippo pathway have recently been developed in the form of YAP-TEAD binding inhibitors. These inhibitors prevent activation of pro-proliferation and anti-apoptotic Hippo pathway effectors. In this study, we show that PAK inhibition slows cell proliferation while TEAD inhibition promotes apoptotic cell death. Finally, we demonstrate the efficacy of PAK and TEAD inhibitor combinations in several NF2-deficient Schwannoma cell lines.

Selective nitration of Hsp90 acts as a metabolic switch promoting tumor cell proliferation

Tumors develop in an oxidative environment characterized by peroxynitrite production and downstream protein tyrosine (Y) nitration. We showed that tyrosine nitration supports schwannoma cell proliferation and regulates cell metabolism in the inheritable tumor disorder NF2-related Schwannomatosis (NF2-SWN). Here, we identified the chaperone Heat shock protein 90 (Hsp90) as the first nitrated protein that acts as a metabolic switch to promote schwannoma cell proliferation. Doubling the endogenous levels of nitrated Hsp90 in schwannoma cells or supplementing nitrated Hsp90 into normal Schwann cells increased their proliferation. Metabolically, nitration on either Y33 or Y56 conferred Hsp90 distinct functions; nitration at Y33 (Hsp90NY33) down-regulated mitochondrial oxidative phosphorylation, while nitration at Y56 (Hsp90NY56) increased glycolysis by activating the purinergic receptor P2X7 in both schwannoma and normal Schwann cells. Hsp90NY33 and Hsp90NY56 showed differential subcellular and spatial distribution corresponding with their metabolic and proliferative functions in schwannoma three-dimensional cell culture models. Collectively, these results underscore the role of tyrosine nitration as a post-translational modification regulating critical cellular processes. Nitrated proteins, particularly nitrated Hsp90, emerge as a novel category of tumor-directed therapeutic targets.

Influence of Magnesium Degradation on Schwannoma Cell Responses to Nerve Injury Using an In Vitro Injury Model.

Nerve guidance conduits for peripheral nerve injuries can be improved using bioactive materials such as magnesium (Mg) and its alloys, which could provide both structural and trophic support. Therefore, we investigated whether exposure to Mg and Mg-1.6wt%Li thin films (Mg/Mg-1.6Li) would alter acute Schwann cell responses to injury. Using the RT4-D6P2T Schwannoma cell line (SCs), we tested extracts from freeze-killed cells (FKC) and nerves (FKN) as in vitro injury stimulants. Both FKC and FKN induced SC release of the macrophage chemoattractant protein 1 (MCP-1), a marker of the repair SC phenotype after injury. Next, FKC-stimulated cells exposed to Mg/Mg-1.6Li reduced MCP-1 release by 30%, suggesting that these materials could have anti-inflammatory effects. Exposing FKC-treated cells to Mg/Mg-1.6Li reduced the gene expression of the nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF), and myelin protein zero (MPZ), but not the p75 neurotrophin receptor. In the absence of FKC, Mg/Mg-1.6Li treatment increased the expression of NGF, p75, and MPZ, which can be beneficial to nerve regeneration. Thus, the presence of Mg can differentially alter SCs, depending on the microenvironment. These results demonstrate the applicability of this in vitro nerve injury model, and that Mg has wide-ranging effects on the repair SC phenotype.

Sublingual Space Schwannoma: An Uncommon Tumour in a Unique Anatomical Location.

A Schwannoma is a benign tumour originating from Schwann cells within theperipheral, cranial, or autonomic nerves. Typically, these tumours manifest as a solitary, slow-growing mass with smooth surface, usually devoid of significant symptoms. Schwannomas most frequently appear in individuals aged 30-50years. Although they are relatively uncommon, approximately one-fourth of all Schwannomas are found in the head and neck area. Its occurrence within the oral cavity, with the tongue being the most common site, followed by the palate, floor of the mouth, buccal mucosa, lips, and jaws. Diagnosing these tumours before surgery can be challenging, and in most instances, a definitive diagnosis can only be established through surgical intervention and subsequent histological examination. Immunohistochemistry plays a crucial role in confirming the diagnosis, as it shows that Schwannoma cells exhibit a positive reaction to the S-100 protein. Here, we present a case of a Schwannoma in the floor of the mouth, observed in an 18-year-old male patient.

Retraction: Ailanthone promotes human vestibular schwannoma cell apoptosis and autophagy by downregulation of miR-21.

[This retracts the article DOI: 10.3727/096504018X15149775533331.].

Outcomes of Extended Middle Fossa Approach for Petroclival Tumors in the Elderly.

Objective The aims of the study are (1) to evaluate the extended middle fossa approach (eMCF) for resection of tumors in the petroclivus and anterior cerebellopontine angle (CPA) and (2) to compare surgical outcomes between elderly (≥65 years) and nonelderly patients. Design Retrospective cohort. Setting Tertiary referral center. Participants Adults with petroclival, anterior CPA, or posterior fossa lesions who underwent an eMCF approach from 2012 to 2021 were included in the study. Main Outcome Measure Demographics, symptoms, cranial nerve (CN) function, and postoperative outcomes. Results Twenty-nine patients (mean age of 55 years, 59% females) were identified. Eleven (38%) were ≥65 years (65-79 years). The most common pathology was meningioma ( n = 13, 45%), followed by vestibular schwannoma ( n = 4, 14%) and squamous cell carcinoma ( n = 3, 10%). Nineteen tumors (65.5%) were located in the petroclivus, 7 (24%) involved the cavernous sinus, and 10 (34%) were located in the posterior fossa. The mean tumor maximal diameter was 3.4 cm (range: 1.3-7.9 cm). Gross total tumor resection was accomplished in 15 (52%) patients. Most patients ( n = 23, 79%) did not develop new CN deficits postoperatively. Of the 13 patients who had complete pre- and postoperative audiometric data, 69% ( n = 9) maintained their hearing. Comparing the elderly versus nonelderly patients, there were no significant differences in the development of new CN palsies ( p = 0.14), length of stay ( p = 0.91), or incidence of postoperative complications ( p = 0.30). Conclusions The eMCF approach provides exposure to the petroclival region, anterior CPA cistern, and posterior fossa for a variety of pathologies. It has a favorable safety profile in the elderly (≥65 years) population with low morbidity.

Immune Profiling of Secreted Factors from Human Vestibular Schwannoma Cells and Tumor-associated Macrophages.

This study compared the immune-related secretory capacity of human vestibular schwannoma (VS) and tumor-assisted macrophages (TAMs) with their normal counterparts (Schwann cells [SC] and peripheral blood monocyte-derived macrophages [Mo-MFs], respectively), and examined relationships with presurgical hearing and tumor size. VS tumors (n = 16), auditory nerve (n = 1), blood (n = 9), and great auricular nerves (n = 3) were used. SCs (S100B+ ) and TAMs (CD68+ ) were isolated from VS tissue for culture. The secreted levels of 65 immune-related factors were measured and compared using unpaired t-tests with Welch correction (schwannoma vs. SCs) or Mann-Whitney tests (TAMs and Mo-MFs). Associations between factor concentration and word recognition (WR), pure-tone average (PTA), and tumor size were evaluated with Spearman correlation. Secreted factors with significantly higher concentrations in schwannoma versus SC supernatants included IL-2 and BAFF, whereas MMP-1, IL-6, FGF-2, VEGF-A, MIP-3α, and GRO-α concentrations were significantly higher in TAMs versus Mo-MFs (all p < 0.05). Worse WR was significantly associated with higher secretion of fractalkine, eotaxin-3, CD30, and IL-16 by VS cells; IP-10, eotaxin-3, multiple interleukins, GM-CSF, SCF, and CD30 by TAMs; and TNF-α and MIP-1α by Mo-MFs (all p < 0.05). Worse PTA was significantly correlated with higher secretion of IL-16 by VS cells (p < 0.05). Larger tumor size was significantly correlated with higher secretion of eotaxin by VS cells, and of IL-7, IL-21, and LIF by TAMs (all p = 0.017). Differential secretion of immune-related factors was observed in schwannoma versus normal SCs and in TAMs versus Mo-MFs, some of which were correlated with worse hearing and larger VS tumors. N/A Laryngoscope, 134:S1-S14, 2024.

Metformin Reduces Tumor Growth in a Murine Flank Schwannoma Model.

Metformin and aspirin reduce vestibular schwannoma (VS) growth. There have been reported associations between patients with VS prescribed metformin and decreased tumor volumetric growth. Aspirin has also been associated with decreased VS growth in animal studies. Rat schwannoma cell lines were grown and implanted into 50 athymic nude mice. Tumors were grown to 5 mm, and then mice were injected with either low- or high-dose metformin, aspirin, or saline daily. Tumors were measured until 14 days elapsed or mice demonstrated symptoms such as ulceration, inability to walk, or passed away. There were no significant differences in day 0 tumor sizes between the control and the treatment groups ( p = 0.73). In the low-dose, but not high-dose groups, day 7 volumes were significantly different for both metformin ( p = 0.04) and aspirin ( p = 0.02) compared with placebo. Mean tumor growth rates were 126.6 ± 65.6 mm 3 /day for saline compared with 73.7 ± 29.5 mm 3 /day for low-dose metformin ( p = 0.03) and 68.7 ± 34.8 mm 3 /day for low-dose aspirin ( p = 0.016). There were no significant differences in tumor sizes ( p = 0.59) or growth rates ( p = 0.75) between low-dose metformin and aspirin groups. Low-dose groups had treatment stopped at 14 days, with continued monitoring demonstrating significant increases in tumor growth off treatment for both aspirin ( p = 0.006) and metformin ( p = 0.048). Metformin treatment significantly reduced VS growth to a similar level as aspirin. Furthermore, when removing both metformin and aspirin treatment, tumor growth significantly increased.

Utility of Targeted Positron Emission Tomography Imaging to Predict Schwannoma Growth in a Murine Tumor Model.

To identify if targeted positron emission tomography (PET) imaging with radiolabeled antibodies can predict tumor growth rate and ultimate tumor size in a murine flank schwannoma model. Animal research study. Rat schwannoma cells were cultured and implanted into 40 athymic nude mice. Once tumors reached 5 mm in diameter, 30 mice were injected with zirconium-89 labeled antibodies (HER2/Neu, vascular endothelial growth factor receptor 2 (VEGFR2), or IgG isotype). PET/CT was performed, and standardized uptake values (SUV) were recorded. Tumors were serially measured until mice were sacrificed per IACUC protocol. Statistical analysis was performed to measure correlations between SUV values, tumor size, and growth. Mean tumor sizes in mm3 on Day 0 were 144 ± 162 for anti-HER2/Neu, 212 ± 247 for anti-VEGFR2, and 172 ± 204 for IgG isotype groups respectively. Mean growth rates in mm3 /day were 531 ± 250 for HER2, 584 ± 188 for VEGFR2, and 416 ± 163 for the IgG isotype group. For both initial tumor size and growth rates, there was no significant difference between groups. There were significant correlations between maximum tumor volume and both the SUV max in the HER2 group (p = 0.0218, R2 = 0.5020), and we observed significant correlations between growth rate, and SUV values (p = 0.0156, R2 = 0.5394). Respectively, in the anti-VEGFR2 group, there were no significant correlations. In a murine schwannoma model, immunotargeted PET imaging with anti-HER2/Neu antibodies predicted tumor growth rate and final tumor size. Laryngoscope, 134:1372-1380, 2024.

Cotargeting Phosphoinositide 3-Kinase and Focal Adhesion Kinase Pathways Inhibits Proliferation of NF2 Schwannoma Cells.

Neurofibromatosis Type 2 (NF2) is a tumor predisposition syndrome caused by germline inactivating mutations in the NF2 gene encoding the merlin tumor suppressor. Patients develop multiple benign tumor types in the nervous system including bilateral vestibular schwannomas (VS). Standard treatments include surgery and radiation therapy, which may lead to loss of hearing, impaired facial nerve function, and other complications. Kinase inhibitor monotherapies have been evaluated clinically for NF2 patients with limited success, and more effective nonsurgical therapies are urgently needed. Schwannoma model cells treated with PI3K inhibitors upregulate activity of the focal adhesion kinase (FAK) family as a compensatory survival pathway. We screened combinations of 13 clinically relevant PI3K and FAK inhibitors using human isogenic normal and merlin-deficient Schwann cell lines. The most efficacious combination was PI3K/mTOR inhibitor omipalisib with SRC/FAK inhibitor dasatinib. Sub-GI50 doses of the single drugs blocked phosphorylation of their major target proteins. The combination was superior to either single agent in promoting a G1 cell-cycle arrest and produced a 44% decrease in tumor growth over a 2-week period in a pilot orthotopic allograft model. Evaluation of single and combination drugs in six human primary VS cell models revealed the combination was superior to the monotherapies in 3 of 6 VS samples, highlighting inter-tumor variability between patients consistent with observations from clinical trials with other molecular targeted agents. Dasatinib alone performed as well as the combination in the remaining three samples. Preclinically validated combination therapies hold promise for NF2 patients and warrants further study in clinical trials.

Abstract LB326: Combined inhibition of BRD4 and FAK1 as a novel therapeutic strategy for neurofibromatosis type 2 related schwannomas

Abstract Neurofibromatosis type 2 (NF2) is a rare disorder that is inherited in an autosomal-dominant manner and is attributed to the loss of heterozygosity (LOH) of the NF2 gene, which encodes for the tumor suppressor protein Merlin. Patients affected by the disease develop vestibular schwannomas (VS), meningiomas, and ependymomas resulting in high morbidity and premature mortality. To date, neurofibromatosis type 2 has no FDA-approved drug-based treatment. Merlin plays a central role in mediating cell contact inhibition (CI) of proliferation. Loss of Merlin leads to abnormal activation of multiple signaling pathways, including those regulated by small G-proteins Ras/Rac/cdc42 and the Hippo-YAP pathway. The Hippo-YAP pathway plays a major role in cell growth and organ size control and at its core is comprised of a kinase cascade that regulates the transcriptional regulator YAP. The function of YAP is crucial for VS development, and there are several mechanisms by which YAP regulates transcription. Some of these functions have been shown to involve the Bromodomain and Extra-Terminal domain (BET) proteins acting as co-factors. We have previously shown that the BET inhibitor JQ1 can selectively reduce the growth of the NF2-null schwannoma and Schwann cells in vitro and tumorigenesis in vivo. Additionally, evidence has shown that Merlin loss can lead to increased cell proliferation that it requires the activity of Focal Adhesion Kinase 1 (FAK1). We have previously demonstrated that FAK1 inhibition via Crizotinib has antiproliferative effects in NF2-null Schwann cells, and is currently in phase II clinical trials in NF2-related VS. In this study, wild-type and NF2-null Schwann cells and schwannoma cell lines were used to determine the impact on cell growth by employing the treatment with the BET inhibitor JQ1 and the FAK1 inhibitor Crizotinib. Our analysis in NF2-null Schwann cells and schwannoma cell lines shows that the combined inhibition exerts an antineoplastic effect at nanomolar concentrations. Moreover, this combination resulted in selective inhibition of NF2-null Schwann cell proliferation when compared to wild-type Schwann cells in vitro, when compared to either drug alone. Our preliminary data suggest that combined targeting of BET and FAK1 may offer a potential therapeutic option for the treatment of NF2-related schwannomas. Citation Format: Maria Alejandra Gonzalez, Joseph Kissil, Scott Troutman. Combined inhibition of BRD4 and FAK1 as a novel therapeutic strategy for neurofibromatosis type 2 related schwannomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB326.

Abstract 2629: Single and combined inhibition of PAK and Hippo pathway in NF2-deficient schwannoma

Abstract Neurofibromatosis 2 (NF2) Syndrome is a rare, but devastating genetic condition that leads to non-cancerous tumors of the nervous system. NF2 patients are likely to develop Schwannomas on the eighth cranial nerve that lead to progressive deafness and spinal cord compression as well as meningiomas and peripheral nerve tumors. Effective treatment for these patients is lacking, with risky surgery being the most reliable approach and pharmacotherapies having inadequate results. The hallmark mutation of this condition is inactivation of NF2, which codes for the protein Merlin. Merlin plays several roles in the cell, two of the most consequential being inhibition of PAK1 and activation of the Hippo tumor suppressor pathway. However, drugs targeting these pathways have not yet been investigated in NF2-deficient Schwannoma. In this study, we explored the use of YAP-TEAD inhibitors as well as the combination of Hippo family and Group I PAK inhibition in NF2-deficient Schwannoma cells. We used several Schwannoma cells lines of human, mouse, and rat origin as well as a human Schwann cell line with NF2 knocked out via CRISPR compared to its wild-type control line. We investigated the role of YAP, the main effector of the Hippo pathway, and PAK1/2 in NF2 Schwannoma cells via genetic and pharmacologic inhibition. We also combined YAP-TEAD inhibitors with several PAK family inhibitors to induce a synergistic reduction in cell viability and proliferation as well as an increase in apoptosis. We found that genetic inhibition of both YAP and Group I PAK proteins led to partial reduction in Schwannoma growth. Using several YAP-TEAD binding inhibitors (TED-347, NSC682769, IK-930), Group I PAK inhibitors (FRAX-1036, G555) and PAK1-specific inhibitor (NVS-1-PAK1) we found that YAP-TEAD binding inhibition combined with Group I PAK inhibition has the greatest reduction on Schwannoma cell viability, proliferation, and increase in cell death. Taken together, our findings indicate that both the Hippo pathway and PAK proteins may be viable targets for Schwannoma therapies. Furthermore, combining the two may lead to a synergistic effect and further prevent growth of NF2-deficient Schwannomas. Citation Format: Dorothy Benton, Jonathan Chernoff. Single and combined inhibition of PAK and Hippo pathway in NF2-deficient schwannoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2629.

Designing a Prolonged Method of Therapeutic Delivery to Support Rehabilitation From Ototoxic Damage in a Schwann Cell Model.

The ototoxicity of gentamicin and cisplatin can be evaluated with a Schwann cell model to screen for otoprotective agents that can be encapsulated into poly (lactic-co-glycolic acid) (PLGA) microparticles for drug delivery to the inner ear. Aminoglycosides and cisplatin are widely prescribed but known to cause ototoxicity. There is strong evidence that compromise to Schwann cells ensheathing inner ear afferent neurons results in inner ear dysfunction mimicking drug-induced ototoxicity. There is a need for a model for ototoxic demyelination to screen medications for protective potential and to subsequently target and tune the delivery of any promising agents. RT4-D6P2T rat schwannoma cells were used as a Schwann cell model to assess gentamicin and cisplatin toxicity and to screen for protective agents. Cell viability was evaluated with the MTT cell proliferation assay. N -acetylcysteine (NAC) was encapsulated into a PLGA microparticle, and its elution profile was determined. The estimated 50% lethal concentration dose for gentamicin was 805.6 μM, which was 46-fold higher than that for cisplatin (17.5 μM). In several trials, cells dosed with NAC and cisplatin demonstrated a 22.6% ( p < 0.001) increase in cell viability when compared with cisplatin alone. However, this protective effect was not consistent across all trials. NAC was encapsulated into a PLGA microparticle and elution plateaued at 5 days. When dosed at their respective therapeutic ranges, cisplatin is more likely than gentamicin to induce damage to the Schwann cell model. Although NAC demonstrates an uncertain role in protecting against cisplatin-induced Schwann cell cytotoxicity, this study establishes a method to screen for other otoprotective medications to encapsulate into a tunable microparticle for localized drug delivery.

Synchronous Retroperitoneal Schwannoma and Incidental Papillary Renal Cell Carcinoma: A Case Report

Background: Retroperitoneal schwannoma is a rare tumor rising from Schwann cells in peripheral nerve sheaths. Retroperitoneal schwannoma is really infrequent and has nonspecific symptoms and imperfect radiologic features, and is often identified histologically after surgery.&#x0D; Case Report: We report the case of a 73-year-old man presented with flank mass. Imaging shows a hypoechoic macro lobulated solid cystic mass in retroperitoneum. Intraoperatively, after complete resection of retroperitoneal mass, a suspected lesion in upper pole of right kidney was observed. Histopathology evaluation after surgery shows coexistence of a large retroperitoneal schwannoma and papillary renal cell carcinoma, type 1.&#x0D; Conclusion: Schwannoma should be considered in the differential diagnosis of retroperitoneal spindle cell tumor. Schwannoma coexisted with renal cell carcinoma in a patient is an unusual event. Thus, it can show the importance of appropriate evaluation before any surgery.

Electroceutical approach ameliorates intracellular PMP22 aggregation and promotes pro-myelinating pathways in a CMT1A in vitro model

Charcot-Marie-Tooth disease subtype 1A (CMT1A) is one of the most prevalent demyelinating peripheral neuropathies worldwide, caused by duplication of the peripheral myelin protein 22 (PMP22) gene, which is expressed primarily in Schwann cells (SCs). PMP22 overexpression in SCs leads to intracellular aggregation of the protein, which eventually results in demyelination. Unfortunately, previous biochemical approaches have not resulted in an approved treatment for CMT1A disease, compelling the pursuit for a biophysical approach such as electrical stimulation (ES). However, the effects of ES on CMT1A SCs have remained unexplored. In this study, we established PMP22-overexpressed Schwannoma cells as a CMT1A in vitro model, and investigated the biomolecular changes upon applying ES via a custom-made high-throughput ES platform, screening for the condition that delivers optimal therapeutic effects. While PMP22-overexpressed Schwannoma exhibited intracellular PMP22 aggregation, ES at 20 Hz for 1 h improved this phenomenon, bringing PMP22 distribution closer to healthy condition. ES at this condition also enhanced the expression of the genes encoding myelin basic protein (MBP) and myelin-associated glycoprotein (MAG), which are essential for assembling myelin sheath. Furthermore, ES altered the gene expression for myelination-regulating transcription factors Krox-20, Oct-6, c-Jun and Sox10, inducing pro-myelinating effects in PMP22-overexpressed Schwannoma. While electroceuticals has previously been applied in the peripheral nervous system towards acquired peripheral neuropathies such as pain and nerve injury, this study demonstrates its effectiveness towards ameliorating biomolecular abnormalities in an in vitro model of CMT1A, an inherited peripheral neuropathy. These findings will facilitate the clinical translation of an electroceutical treatment for CMT1A.

Subgemmal neurogenous plaques of the tongue: a systematic autopsy study.

Subgemmal neurogenous plaque (SNP) is a subepithelial nerve plexus associated with taste buds, occasionally observed in tongue biopsies. There is no evaluation of the prevalence of this structure in the general population. We present a systematic study of samples obtained at random from the dorsal portion of the oral tongue in 205 consecutive complete autopsies. Each sample was about 15 mm long and 10 mm thick. Four hundred fifty-eight samples were routinely obtained and an average of 2.23±0.88 samples per case (range 1-7) was collected. The total number of SNPs observed was 556, with a mean of 2.71±2.68 per case (range 0-16). This means that for every 15 linear mm of the oral tongue, approximately 2.7 SNPs can be present. SNPs display several ages, and they do not show sex differences. The mean size of these structures was 2.1±0.94 mm (range 0.6-3.6 mm). SNP is characterized by its unique neural, zonal pattern with a superficial neurofibroma-like area and a deeper neuroma-like area. Special features of the SNPs include the presence of taste buds (49.1%), ganglion cells (26.3%), dilated thin-walled vessels (11.3%), salivary gland excretory ducts emptying on the surface of the papillae (6.1%), moderate-severe inflammatory infiltrate (6.8%), presence of lymphoid tissue in the vicinity (7.0%), and hyperplasia of the epithelial cover with pseudoepitheliomatous appearance (7.0%). The differential diagnoses include schwannoma, neurofibroma, ganglioneuroma, traumatic neuroma, mucosal neuroma, and squamous cell carcinoma. SNPs are small, normal structures that may undergo hyperplasia and are usually seen incidentally.

Nerve Targeting via Myelin Protein Zero and the Impact of Dimerization on Binding Affinity.

Surgically induced nerve damage is a common but debilitating side effect. By developing tracers that specifically target the most abundant protein in peripheral myelin, namely myelin protein zero (P0), we intend to support fluorescence-guided nerve-sparing surgery. To that end, we aimed to develop a dimeric tracer that shows a superior affinity for P0. Following truncation of homotypic P0 protein-based peptide sequences and fluorescence labeling, the lead compound Cy5-P0101-125 was selected. Using a bifunctional fluorescent dye, the dimeric Cy5-(P0101-125)2 was created. Assessment of the performance of the mono- and bi-labeled compounds was based on (photo)physical evaluation. This was followed by in vitro assessment in P0 expressing Schwannoma cell cultures by means of fluorescence confocal imaging (specificity, location of binding) and flow cytometry (binding affinity; KD). Dimerization resulted in a 1.5-fold increase in affinity compared to the mono-labeled counterpart (70.3 +/- 10.0 nM vs. 104.9 +/- 16.7 nM; p = 0.003) which resulted in a 4-fold increase in staining efficiency in P0 expressing Schwannoma cells. Presence of two targeting vectors also improves a pharmacokinetics of labeled compounds by lowering serum binding and optical stability by preventing dye stacking. Dimerization of the nerve-targeting peptide P0101-125 proves a valid strategy to improve P0 targeting.