Basement membrane proteins in extracellular matrix characterize NF1 neurofibroma development and response to MEK inhibitor

Mass spectrometric insights into the protein composition of human cutaneous neurofibromas: comparison of neurofibromas with the overlying skin

BACKGROUND

Cutaneous neurofibromas (cNFs) are the hallmark of the tumor-predisposition syndrome neurofibromatosis 1 (NF1). While cNFs are always benign, they markedly decrease quality of life in individuals with NF1. Understanding the differences between cNFs and the skin is essential for developing treatments for cNFs.

METHODS

We collected 15 cNFs from four NF1 individuals and used mass spectrometry to compare the tumor tissue with the skin overlying each tumor. Data were analyzed based on Gene Ontology (GO) terms.

RESULTS

The expression patterns of the Schwann cell marker S100B and several keratins confirmed successful dissection of cNF tissue from the overlying skin. Hierarchical clustering showed extensive overlap between the tumor and skin samples in three out of four individuals, suggesting high overall similarity between the two tissue types. Based on the analysis of the GO terms, cNFs were associated with decreased expression of proteins related to cell proliferation, extracellular matrix remodeling, angiogenesis and cellular metabolism.

CONCLUSION

The cNFs are relatively quiescent, consistent with their benign nature and limited growth potential. The development of pharmacological therapy for cNFs requires overcoming the high similarity between cNFs and the overlying skin. The present dataset can serve as a resource for future research on cNFs.

Loss of neurofibromin induces inflammatory macrophage phenotypic switch and retinal neovascularization via GLUT1 activation

Persons with neurofibromatosis type 1 (NF1) exhibit enhanced glucose metabolism, which is replicated in Nf1-mutant mice. Inflammatory macrophages invest NF1-associated tumors, and targeting macrophages appears efficacious in NF1 models. Inflammatory macrophages rely on glycolysis to generate ATP; thus, identifying whether neurofibromin, the protein encoded by NF1, controls glucose metabolism in macrophages is therapeutically compelling. Using neurofibromin-deficient macrophages and macrophage-specific Nf1-knockout mice, we demonstrate that neurofibromin complexes with glucose transporter-1 (GLUT1) to restrain its activity and that loss of neurofibromin permits Akt2 to facilitate GLUT1 translocation to the membrane. In turn, glucose internalization and glycolysis are upregulated and provoke reparative (MIL4) macrophages to undergo an inflammatory phenotypic switch. Inflammatory MLPSIFNγ macrophages and inflammatory-like MIL4 macrophages invest the perivascular stroma of tumors and induce pathologic angiogenesis in macrophage-specific Nf1-knockout mice. These studies identify a mechanism for the enhanced glycolysis associated with NF1 and provide a novel therapeutic target for NF1.

Discoidin domain receptor inhibitor DDR1-IN-1 induces autophagy and necroptotic cell death in malignant peripheral nerve sheath tumor

Malignant peripheral nerve sheath tumor (MPNST) is a soft tissue sarcoma commonly associated with the tumor-predisposition disorder neurofibromatosis 1. The extracellular matrix collagens contribute to many fibrotic tumors; however, the role of collagen signaling in MPNST was unclear. This study investigated the effects of blocking the interaction between collagens and their receptors in MPNST. We first analyzed the expressions of collagen family proteins in MPNSTs and found an overall increase compared to neurofibroma. Treatment of DDR1-IN-1, a small molecule inhibitor for the collagen receptor discoidin domain receptor, induced a robust MPNST cell death, highlighting the dependence of MPNST survival on collagen signaling. DDR1-IN-1 induced MPNST cell death by activating autophagy and necroptosis signaling. Treatment of necroptosis inhibitors necrostatin-1 or necrosulfonamide reduced the numbers of DDR1-IN-1-induced necrotic cells and autolysosomes, suggesting that the autophagic process depends on necroptosis activation. Combinations of DDR1-IN-1 with other anti-MPNST agents revealed synergistic activities against MPNST. In summary, this study discovered a critical MPNST death signaling induced by the small molecule DDR1-IN-1, which might shed light on future MPNST therapeutic strategies.

Schwann Cells Deficient in Neurofibromin Lack Sensitivity to Their Biomechanical Microenvironment

BACKGROUND AND AIMS

Plexiform neurofibromas (PNFs) are benign tumors of the peripheral nervous system that affect approximately 30% of people with neurofibromatosis type 1 (NF1). Schwann cells (SCs), the tumor progenitor cells, respond to and use biomechanical signals like tissue stiffness and mechanical loads in their maintenance and repair functions in healthy tissues. PNFs are described as having altered biomechanics, and we hypothesize this plays a role in PNF development. As a first step in studying the role that altered biomechanics may play in the development of PNFs, we aimed to determine how PNF SCs alter in their response to various biomechanical signals as compared to healthy SCs.

METHODS

We examined the behavior of healthy and PNF SCs in three different tissue-mimicking biomechanical models. First, we examined their spreading behavior on extracellular matrix (ECM) protein-coated polyacrylamide hydrogels of varying stiffness in the healthy and pathological range. Second, we investigated their collective migration with respect to substrate stiffness and ECM protein-coating. Finally, we generated multicellular spheroid tissue models using healthy and PNF SCs and measured their mechanical properties as a function of spheroid size.

RESULTS

We found that PNF SCs are differently sensitive to substrate stiffness in a physiological range compared to healthy SCs, lack sensitivity to ECM protein coating when collectively migrating, and lack sensitivity to environmental deficiencies in oxygen and nutrient supplies when in spheroid culture.

INTERPRETATION

We propose that PNF SC altered biomechanics likely play a role in tumor initiation and progression, and that further biomechanical-based investigations of NF1 tumor growth are needed.

A novel basement membrane-related gene signature for predicting prognosis of HNSCC

In recent years, a notably heterogeneous malignant tumor, squamous cell carcinoma of the head and neck (HNSCC), has received increasing attention, with no significant improvement in its survival rate. The rapid increase in the number of prognostic models associated with HNSCC has been observed due to its accuracy, which offers crucial clinical benefits. The 10 genes were selected from 222 human genes associated with the basement membrane in the analysis of this article. The gene pool was narrowed through different classifications and intersections, followed by univariate Cox regression analysis. Genes with statistical significance underwent further Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis, resulting in the final selection of 10 genes. The data and images extracted from the Human Protein Atlas database were utilized to confirm the differential expression of the corresponding genes. Multivariate Cox regression analysis was employed to develop a nomogram, and the nomogram was assessed by additional decision curve analysis (DCA). The Gene Expression Omnibus validation set was used to validate the established model. Finally, between the high- and low-risk score groups, Gene Set Enrichment Analysis, immune correlation analysis, and drug sensitivity analysis were conducted in this paper. ITGA5, SPOCK1, EVA1C, TINAGL1, LAMB4, ADAMTS1, EGFL6, GPC2, BGN, and ITGA2B were successfully developed as basement membrane-associated risk models. The time-dependent receiver operating characteristic (timeROC) curve illustrated that the risk score prediction accuracy outperformed indicators, which were commonly adopted in clinical practice, consisting of age, stage, gender, T-staging, and N-staging. The 3-year risk score timeROC area under the curve value was 0.679. This model demonstrates a reliable ability to assess the prognosis of HNSCC patients. In addition, the specific potential biomarkers associated with the basement membrane were explored in this research.

Emerging mechanism and therapeutic potential of neurofibromatosis type 1-related nerve system tumor: Advancing insights into tumor development

Neurofibromatosis Type 1 (NF1) is a genetic disorder resulting from mutations in the NF1 gene, which increases susceptibility to various nervous system tumors, including plexiform neurofibromas, malignant peripheral nerve sheath tumors, and optic pathway gliomas. Recent research has shown that these tumors are intricately connected to the complex, dynamic interactions within neurons, culminating in neuronal signaling that fosters tumor growth. These interactions offer crucial insights into the molecular mechanisms underpinning tumor development, as well as broader implications for therapeutic strategies. This review summarizes the mechanisms through which mutations in the NF1 gene within neural tissues trigger tumorigenesis, while examining the role of the neuron-via factors such as visual experience, neurotransmitter, tumor microenvironment, and psychological influences-in both promoting tumor progression and being affected by the tumors themselves. By investigating the dynamic relationship between NF1-associated nervous system tumor cells and neurons, we aim to shed light on novel biological pathways and disease processes, emphasizing the potential of interdisciplinary approaches that combine neurobiology, oncology, and pharmacology to enhance treatment strategies and even inhibit the tumorigenesis.

Targeting the peripheral neural-tumour microenvironment for cancer therapy

As the field of cancer neuroscience expands, the strategic targeting of interactions between neurons, cancer cells and other elements in the tumour microenvironment represents a potential paradigm shift in cancer treatment, comparable to the advent of our current understanding of tumour immunology. Cancer cells actively release growth factors that stimulate tumour neo-neurogenesis, and accumulating evidence indicates that tumour neo-innervation propels tumour progression, inhibits tumour-related pro-inflammatory cytokines, promotes neovascularization, facilitates metastasis and regulates immune exhaustion and evasion. In this Review, we give an up-to-date overview of the dynamics of the tumour microenvironment with an emphasis on tumour innervation by the peripheral nervous system, as well as current preclinical and clinical evidence of the benefits of targeting the nervous system in cancer, laying a scientific foundation for further clinical trials. Combining empirical data with a biomarker-driven approach to identify and hone neuronal targets implicated in cancer and its spread can pave the way for swift clinical integration.

Mannan-Decorated Lipid Calcium Phosphate Nanoparticle Vaccine Increased the Antitumor Immune Response by Modulating the Tumor Microenvironment

With the rapid development of tumor immunotherapy, nanoparticle vaccines have attracted much attention as potential therapeutic strategies. A systematic review and analysis must be carried out to investigate the effect of mannose modification on the immune response to nanoparticles in regulating the tumor microenvironment, as well as to explore its potential clinical application in tumor therapy. Despite the potential advantages of nanoparticle vaccines in immunotherapy, achieving an effective immune response in the tumor microenvironment remains a challenge. Tumor immune escape and the overexpression of immunosuppressive factors limit its clinical application. Therefore, our review explored how to intervene in the immunosuppressive mechanism in the tumor microenvironment through the use of mannan-decorated lipid calcium phosphate nanoparticle vaccines to improve the efficacy of immunotherapy in patients with tumors and to provide new ideas and strategies for the field of tumor therapy.

Laminin I mediates resistance to lapatinib in HER2-positive brain metastatic breast cancer cells in vitro

The role of extracellular matrix (ECM) prevalent in the brain metastatic breast cancer (BMBC) niche in mediating cancer cell growth, survival, and response to therapeutic agents is not well understood. Emerging evidence suggests a vital role of ECM of the primary breast tumor microenvironment (TME) in tumor progression and survival. Possibly, the BMBC cells are also similarly influenced by the ECM of the metastatic niche; therefore, understanding the effect of the metastatic ECM on BMBC cells is imperative. Herein, we assessed the impact of various ECM components (i.e., Tenascin C, Laminin I, Collagen I, Collagen IV, and Fibronectin) on brain metastatic human epidermal growth factor receptor 2 (HER2)-positive and triple negative breast cancer (TNBC) cell lines in vitro. The highly aggressive TNBC cell line was minimally affected by ECM components exhibiting no remarkable changes in viability and morphology. On the contrary, amongst various ECM components tested, the HER2-positive cell line was significantly affected by Laminin I with higher viability and demonstrated a distinct spread morphology. In addition, HER2-positive BMBC cells exhibited resistance to Lapatinib in presence of Laminin I. Mechanistically, Laminin I-induced resistance to Lapatinib was mediated in part by phosphorylation of Erk 1/2 and elevated levels of Vimentin. Laminin I also significantly enhanced the migratory potential and replicative viability of HER2-positive BMBC cells. In sum, our findings show that presence of Laminin I in the TME of BMBC cells imparts resistance to targeted therapeutic agent Lapatinib, while increasing the possibility of its dispersal and clonogenic survival.

snRNA-seq of human cutaneous neurofibromas before and after selumetinib treatment implicates role of altered Schwann cell states, inter-cellular signaling, and extracellular matrix in treatment response

Neurofibromatosis Type 1 (NF1) is caused by loss of function variants in the NF1 gene. Most patients with NF1 develop skin lesions called cutaneous neurofibromas (cNFs). Currently the only approved therapeutic for NF1 is selumetinib, a mitogen -activated protein kinase (MEK) inhibitor. The purpose of this study was to analyze the transcriptome of cNF tumors before and on selumetinib treatment to understand both tumor composition and response. We obtained biopsy sets of tumors both pre- and on- selumetinib treatment from the same individuals and were able to collect sets from four separate individuals. We sequenced mRNA from 5844 nuclei and identified 30,442 genes in the untreated group and sequenced 5701 nuclei and identified 30,127 genes in the selumetinib treated group. We identified and quantified distinct populations of cells (Schwann cells, fibroblasts, pericytes, myeloid cells, melanocytes, keratinocytes, and two populations of endothelial cells). While we anticipated that cell proportions might change with treatment, we did not identify any one cell population that changed significantly, likely due to an inherent level of variability between tumors. We also evaluated differential gene expression based on drug treatment in each cell type. Ingenuity pathway analysis (IPA) was also used to identify pathways that differ on treatment. As anticipated, we identified a significant decrease in ERK/MAPK signaling in cells including Schwann cells but most specifically in myeloid cells. Interestingly, there is a significant decrease in opioid signaling in myeloid and endothelial cells; this downward trend is also observed in Schwann cells and fibroblasts. Cell communication was assessed by RNA velocity, Scriabin, and CellChat analyses which indicated that Schwann cells and fibroblasts have dramatically altered cell states defined by specific gene expression signatures following treatment (RNA velocity). There are dramatic changes in receptor-ligand pairs following treatment (Scriabin), and robust intercellular signaling between virtually all cell types associated with extracellular matrix (ECM) pathways (Collagen, Laminin, Fibronectin, and Nectin) is downregulated after treatment. These response specific gene signatures and interaction pathways could provide clues for understanding treatment outcomes or inform future therapies.

The NF1+/- Immune Microenvironment: Dueling Roles in Neurofibroma Development and Malignant Transformation

Neurofibromatosis type 1 (NF1) is a common genetic disorder resulting in the development of both benign and malignant tumors of the peripheral nervous system. NF1 is caused by germline pathogenic variants or deletions of the NF1 tumor suppressor gene, which encodes the protein neurofibromin that functions as negative regulator of p21 RAS. Loss of NF1 heterozygosity in Schwann cells (SCs), the cells of origin for these nerve sheath-derived tumors, leads to the formation of plexiform neurofibromas (PNF)-benign yet complex neoplasms involving multiple nerve fascicles and comprised of a myriad of infiltrating stromal and immune cells. PNF development and progression are shaped by dynamic interactions between SCs and immune cells, including mast cells, macrophages, and T cells. In this review, we explore the current state of the field and critical knowledge gaps regarding the role of NF1(Nf1) haploinsufficiency on immune cell function, as well as the putative impact of Schwann cell lineage states on immune cell recruitment and function within the tumor field. Furthermore, we review emerging evidence suggesting a dueling role of Nf1+/- immune cells along the neurofibroma to MPNST continuum, on one hand propitiating PNF initiation, while on the other, potentially impeding the malignant transformation of plexiform and atypical neurofibroma precursor lesions. Finally, we underscore the potential implications of these discoveries and advocate for further research directed at illuminating the contributions of various immune cells subsets in discrete stages of tumor initiation, progression, and malignant transformation to facilitate the discovery and translation of innovative diagnostic and therapeutic approaches to transform risk-adapted care.

Topical delivery of mitogen-activated protein kinase inhibitor binimetinib prevents the development of cutaneous neurofibromas in neurofibromatosis type 1 mutant mice

Cutaneous neurofibromas (cNFs) are a hallmark of patients with the neurofibromatosis type 1 (NF1) genetic disorder. These benign nerve sheath tumors, which can amount to thousands, develop from puberty onward, often cause pain and are considered by patients to be the primary burden of the disease. Mutations of NF1, encoding a negative regulator of the RAS signaling pathway, in the Schwann cell (SCs) lineage are considered to be at the origin of cNFs. The mechanisms governing cNFs development are poorly understood, and therapeutics to reduce cNFs are missing, mainly due to the lack of appropriate animal models. To address this, we designed the Nf1-KO mouse model that develops cNFs. Using this model, we found that cNFs development is a singular event and goes through 3 successive stages: initiation, progression, and stabilization characterized by changes in the proliferative and MAPK activities of tumor SCs. We found that skin trauma accelerated the development of cNFs and further used this model to explore the efficacy of the MEK inhibitor binimetinib to cure these tumors. We showed that while topically delivered binimetinib has a selective and minor effect on mature cNFs, the same drug prevents their development over long periods.