Multiomic analyses reveal new targets of polycomb repressor complex 2 in Schwann lineage cells and malignant peripheral nerve sheath tumors.

Background: Malignant peripheral nerve sheath tumors (MPNSTs) can arise from atypical neurofibromas (ANF). Loss of the polycomb repressor complex 2 (PRC2) is a common event. Previous studies on PRC2-regulated genes in MPNST used genetic add-back experiments in highly aneuploid MPNST cell lines which may miss PRC2-regulated genes in -mutant ANF-like precursor cells.

Cell type specific suppression of hyper-recombination by human RAD18 is linked to PCNA K164 ubiquitination.

Homologous recombination (HR) and translesion synthesis (TLS) promote gap-filling DNA synthesis to complete genome replication. One factor involved in both pathways is RAD18, an E3 ubiquitin ligase. Although RAD18's role in promoting TLS through the ubiquitination of PCNA at lysine 164 (K164) is well established, its requirement for HR-based mechanisms is currently less clear.

NF1-dependent disruption of the blood-nerve-barrier is improved by blockade of P2RY14.

The blood-nerve-barrier (BNB) that regulates peripheral nerve homeostasis is formed by endoneurial capillaries and perineurial cells surrounding the Schwann cell (SC)-rich endoneurium. Barrier dysfunction is common in human tumorigenesis, including in some nerve tumors. We identify barrier disruption in human deficient neurofibromas, which were characterized by reduced perineurial cell glucose transporter 1 (GLUT1) expression and increased endoneurial fibrin(ogen) deposition.

Evolution of the clinical-stage hyperactive TcBuster transposase as a platform for robust non-viral production of adoptive cellular therapies.

Cellular therapies for the treatment of human diseases, such as chimeric antigen receptor (CAR) T and natural killer (NK) cells have shown remarkable clinical efficacy in treating hematological malignancies; however, current methods mainly utilize viral vectors that are limited by their cargo size capacities, high cost, and long timelines for production of clinical reagent. Delivery of genetic cargo via DNA transposon engineering is a more timely and cost-effective approach, yet has been held back by less efficient integration rates. Here, we report the development of a novel hyperactive TcBuster (TcB-M) transposase engineered through structure-guided and in vitro evolution approaches that achieves high-efficiency integration of large, multicistronic CAR-expression cassettes in primary human cells.

Conditionally replicative adenovirus as a therapy for malignant peripheral nerve sheath tumors.

Oncolytic adenoviruses (Ads) stand out as a promising strategy for the targeted infection and lysis of tumor cells, with well-established clinical utility across various malignancies. This study delves into the therapeutic potential of oncolytic Ads in the context of neurofibromatosis type 1 (NF1)-associated malignant peripheral nerve sheath tumors (MPNSTs). Specifically, we evaluate conditionally replicative adenoviruses (CRAds) driven by the cyclooxygenase 2 (COX2) promoter, as selective agents against MPNSTs, demonstrating their preferential targeting of MPNST cells compared with non-malignant Schwann cell control.

Pharmacogenomic synthetic lethal screens reveal hidden vulnerabilities and new therapeutic approaches for treatment of NF1-associated tumors.

Neurofibromatosis Type 1 (NF1) is a common cancer predisposition syndrome, caused by heterozygous loss of function mutations in the tumor suppressor gene . Individuals with NF1 develop benign tumors of the peripheral nervous system (neurofibromas), originating from the Schwann cell linage after somatic loss of the wild type allele, some of which progress further to malignant peripheral nerve sheath tumors (MPNST). There is only one FDA approved targeted therapy for symptomatic plexiform neurofibromas and none approved for MPNST.

Radiation Therapy and Myeloid-Derived Suppressor Cells: Breaking Down Their Cancerous Partnership.

Radiation therapy (RT) has been a primary treatment modality in cancer for decades. Increasing evidence suggests that RT can induce an immunosuppressive shift via upregulation of cells such as tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs). MDSCs inhibit antitumor immunity through potent immunosuppressive mechanisms and have the potential to be crucial tools for cancer prognosis and treatment.

CDK4/6 inhibition enhances SHP2 inhibitor efficacy and is dependent upon RB function in malignant peripheral nerve sheath tumors.

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive soft tissue sarcomas with limited treatment options, and new effective therapeutic strategies are desperately needed. We observe antiproliferative potency of genetic depletion of or pharmacological inhibition using the SHP2 inhibitor (SHP2i) TNO155. Our studies into the signaling response to SHP2i reveal that resistance to TNO155 is partially mediated by reduced RB function, and we therefore test the addition of a CDK4/6 inhibitor (CDK4/6i) to enhance RB activity and improve TNO155 efficacy.

Perinatal folate levels do not influence tumor latency or multiplicity in a model of NF1 associated plexiform-like neurofibromas.

Objective: In epidemiological and experimental research, high folic acid intake has been demonstrated to accelerate tumor development among populations with genetic and/or molecular susceptibility to cancer. Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder predisposing affected individuals to tumorigenesis, including benign plexiform neurofibromas; however, understanding of factors associated with tumor risk in NF1 patients is limited. Therefore, we investigated whether pregestational folic acid intake modified plexiform-like peripheral nerve sheath tumor risk in a transgenic NF1 murine model.

Combining nonsense mutation suppression therapy with nonsense-mediated decay inhibition in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) results from germline mutations in the tumor-suppressor gene and predisposes patients to developing nervous system tumors. Twenty percent of NF1 patients harbor nonsense mutations resulting in premature termination codons (PTCs). Nonsense suppression therapies can facilitate ribosomal readthrough of PTCs to restore full-length protein, but their potential in NF1 is underexplored.

Existing and Developing Preclinical Models for Neurofibromatosis Type 1-Related Cutaneous Neurofibromas.

Neurofibromatosis type 1 (NF1) is caused by a nonfunctional copy of the NF1 tumor suppressor gene that predisposes patients to the development of cutaneous neurofibromas (cNFs), the skin tumor that is the hallmark of this condition. Innumerable benign cNFs, each appearing by an independent somatic inactivation of the remaining functional NF1 allele, form in nearly all patients with NF1. One of the limitations in developing a treatment for cNFs is an incomplete understanding of the underlying pathophysiology and limitations in experimental modeling.

DNA Deamination Is Required for Human APOBEC3A-Driven Hepatocellular Carcinoma In Vivo.

Although the APOBEC3 family of single-stranded DNA cytosine deaminases is well-known for its antiviral factors, these enzymes are rapidly gaining attention as prominent sources of mutation in cancer. APOBEC3's signature single-base substitutions, C-to-T and C-to-G in TCA and TCT motifs, are evident in over 70% of human malignancies and dominate the mutational landscape of numerous individual tumors. Recent murine studies have established cause-and-effect relationships, with both human APOBEC3A and APOBEC3B proving capable of promoting tumor formation in vivo.

Indirect CRISPR screening with photoconversion revealed key factors of drug resistance with cell-cell interactions.

Comprehensive screenings to clarify indirect cell-cell interactions, such as those in the tumor microenvironment, especially comprehensive assessments of supporting cells' effects, are challenging. Therefore, in this study, indirect CRISPR screening for drug resistance with cell-cell interactions was invented. The photoconvertible fluorescent protein Dendra2 was inducted to supporting cells and explored the drug resistance responsible factors of supporting cells with CRISPR screenings.

Ex vivo to in vivo model of malignant peripheral nerve sheath tumors for precision oncology.

Background: Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft tissue sarcomas that often develop in patients with neurofibromatosis type 1 (NF1). To address the critical need for novel therapeutics in MPNST, we aimed to establish an ex vivo 3D platform that accurately captured the genomic diversity of MPNST and could be utilized in a medium-throughput manner for drug screening studies to be validated in vivo using patient-derived xenografts (PDX).

Methods: Genomic analysis was performed on all PDX-tumor pairs.

Multiplatform molecular profiling uncovers two subgroups of malignant peripheral nerve sheath tumors with distinct therapeutic vulnerabilities.

Malignant peripheral nerve sheath tumor (MPNST) is a highly aggressive sarcoma, and a lethal neurofibromatosis type 1-related malignancy, with little progress made on treatment strategies. Here, we apply a multiplatform integrated molecular analysis on 108 tumors spanning the spectrum of peripheral nerve sheath tumors to identify candidate drivers of MPNST that can serve as therapeutic targets. Unsupervised analyses of methylome and transcriptome profiles identify two distinct subgroups of MPNSTs with unique targetable oncogenic programs.

RAD-TGTs: high-throughput measurement of cellular mechanotype via rupture and delivery of DNA tension probes.

Mechanical forces drive critical cellular processes that are reflected in mechanical phenotypes, or mechanotypes, of cells and their microenvironment. We present here "Rupture And Deliver" Tension Gauge Tethers (RAD-TGTs) in which flow cytometry is used to record the mechanical history of thousands of cells exerting forces on their surroundings via their propensity to rupture immobilized DNA duplex tension probes. We demonstrate that RAD-TGTs recapitulate prior DNA tension probe studies while also yielding a gain of fluorescence in the force-generating cell that is detectable by flow cytometry.

Sex differences in methylation profiles are apparent in medulloblastoma, particularly among SHH tumors.

Background: Medulloblastoma, the most common malignant pediatric brain tumor, displays marked sex differences in prevalence of the four main molecular subgroups: SHH, WNT, Group 3 and Group 4. Males are more frequently diagnosed with SHH, Group 3 and 4 tumors, which have worse prognoses than WNT tumors. Little is known about sex differences in methylation profiles within subgroups.

Modeling human cancer predisposition syndromes using CRISPR/Cas9 in human cell line models.

The advancement of CRISPR mediated gene engineering provides an opportunity to improve upon preclinical human cell line models of cancer predisposing syndromes. This review focuses on using CRISPR/Cas9 genome editing tools to model various human cancer predisposition syndromes. We examine the genetic mutations associated with neurofibromatosis type 1, Li-Fraumeni syndrome, Gorlin syndrome, BRCA mutant breast and ovarian cancers, and APC mutant cancers.

CDK4/6 inhibition enhances SHP2 inhibitor efficacy and is dependent upon restoration of RB function in malignant peripheral nerve sheath tumors.

Malignant peripheral nerve sheath tumors (MPNST) are highly aggressive soft tissue sarcomas with limited treatment options, and novel effective therapeutic strategies are desperately needed. We observe anti-proliferative efficacy of genetic depletion or pharmacological inhibition using the clinically available SHP2 inhibitor (SHP2i) TNO155. Our studies into the signaling response to SHP2i reveal that resistance to TNO155 is partially mediated by reduced RB function, and we therefore test the addition of a CDK4/6 inhibitor (CDK4/6i) to enhance RB activity and improve TNO155 efficacy.

Identification of Downstream Genes with CRISPR Activation Screening.

Mutations in constitutively activate cell proliferation signaling in malignant neoplasms, such as leukemia and melanoma, and the clarification of comprehensive downstream genes of might lead to the control of cell-proliferative signals of -driven cancers. We previously established that expression and proliferative activity can be controlled with doxycycline and named as THP-1 B11. Using a CRISPR activation library on THP-1 B11 cells with the -off state, survival clones were harvested, and 21 candidate genes were identified.

Developing Bottom-Up Induced Pluripotent Stem Cell Derived Solid Tumor Models Using Precision Genome Editing Technologies.

Advances in genome and tissue engineering have spurred significant progress and opportunity for innovation in cancer modeling. Human induced pluripotent stem cells (iPSCs) are an established and powerful tool to study cellular processes in the context of disease-specific genetic backgrounds; however, their application to cancer has been limited by the resistance of many transformed cells to undergo successful reprogramming. Here, we review the status of human iPSC modeling of solid tumors in the context of genetic engineering, including how base and prime editing can be incorporated into "bottom-up" cancer modeling, a term we coined for iPSC-based cancer models using genetic engineering to induce transformation.

Proliferation and Self-Renewal Are Differentially Sensitive to NRASG12V Oncogene Levels in an Acute Myeloid Leukemia Cell Line.

Unlabelled: NRAS proteins are central regulators of proliferation, survival, and self-renewal in leukemia. Previous work demonstrated that the effects of oncogenic NRAS in mediating proliferation and self-renewal are mutually exclusive within leukemia subpopulations and that levels of oncogenic NRAS vary between highly proliferative and self-renewing leukemia subpopulations. These findings suggest that NRAS activity levels may be important determinants of leukemic behavior.

Multivalent, Bispecific αB7-H3-αCD3 Chemically Self-Assembled Nanorings Direct Potent T Cell Responses against Medulloblastoma.

Few therapeutic options have been made available for treating central nervous system tumors, especially upon recurrence. Recurrent medulloblastoma is uniformly lethal with no approved therapies. Recent preclinical studies have shown promising results for eradicating various solid tumors by targeting the overexpressed immune checkpoint molecule, B7-H3.

In Vitro Insertional Mutagenesis Screen Identifies Novel Genes Driving Breast Cancer Metastasis.

Unlabelled: Metastasis, a complex, multistep process, is responsible for the overwhelming majority of cancer-related deaths. Despite its devastating consequences, it is not possible to effectively treat cancer that has spread to vital organs, the mechanisms leading to metastasis are still poorly understood, and the catalog of metastasis promoting genes is still incomprehensive. To identify new driver genes of metastasis development, we performed an in vitro Sleeping Beauty transposon-based forward genetic screen in nonmetastatic SKBR3 human breast cancer cells.