Biology subjects

Fishel, M.

Publications and source records attributed to Fishel, M..

6 recordsLinked to original sources

bioRxiv2026

PRMT5 is Frequently Upregulated and a Potential Therapeutic Target in MTAP-deficient Malignant Peripheral Nerve Sheath Tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive sarcomas with poor prognosis and a strong tendency for metastasis and relapse. Surgical removal remains the mainstay of treatment but is frequently ineffective or impractical. Currently, no effective targeted therapy exists for this type of malignancy. PRMT5 has recently emerged as a promising therapeutic target in various human cancers with MTAP loss, which results in cancer cell dependency on PRMT5 activity. The frequent loss of MTAP in MPNSTs suggests that PRMT5 inhibition is a promising therapeutic option and enables the stratification of cancer patients with few treatment options. We first examined human nerve sheath tumor samples and found that increased PRMT5 expression and activity correlated with MTAP loss in 86.8% (33/38) of MPNSTs and in atypical neurofibromatous neoplasm with uncertain biologic potential (ANNUBP) (5/5). When PRMT5 activity was inhibited genetically and chemically, the cell growth of MTAP-deficient MPNST cell lines was suppressed, but not that of MTAP-proficient MPNST cell lines. Moreover, in the PRMT5-inhibited MTAP-deficient MPNST cell lines, spontaneous DNA damage accumulation was observed following G2/M cell cycle arrest. The DNA replication stress marker RPA32 decreased, and CHK1 was activated early after PRMT5 knockdown, likely contributing to the accumulation of DNA damage. In addition, we combined PRMT5 inhibition with the DNA-damaging agents doxorubicin and gemcitabine, resulting in synergistic effects and increased cancer cell death in MTAP-deficient MPNST cell lines. Together, these findings identify PRMT5 as a compelling therapeutic target in MTAP-deficient MPNSTs. This PRMT5 inhibition strategy has strong translational potential for MPNSTs. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/710638v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@15abc35org.highwire.dtl.DTLVardef@1fa4ebborg.highwire.dtl.DTLVardef@470c51org.highwire.dtl.DTLVardef@79cc3f_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2026

ZNF423 depletion induces the integrated stress response and represents a potential vulnerability in NF1-associated MPNST

Malignant peripheral nerve sheath tumors (MPNST) are aggressive sarcomas with limited systemic therapies and represent the leading cause of mortality for individuals with neurofibromatosis type 1 (NF1). Malignant progression can reactivate developmental precursor programs that are largely absent from normal nerve and benign tumors, creating tumor-selective vulnerabilities. Zinc finger protein 423 (ZNF423; also known as OAZ/ROAZ) is a developmentally regulated transcription factor that delays olfactory precursor differentiation and has been implicated in B-cell malignancy. Here, we asked whether ZNF423 is reactivated and functionally required in NF1-associated MPNST. In genetically defined models, Nf1 loss reduced Zfp423 in a benign tumor cell-of-origin context, whereas combined Nf1 and Cdkn2a loss induced marked Zfp423 upregulation during transformation. ZNF423 depletion impaired DNA synthesis and proliferation, induced DNA damage signaling, and activated the integrated stress response (ISR), increasing sensitivity to cytotoxic agents. In an orthotopic MPNST model, shRNA-mediated suppression of ZNF423 reduced tumor initiation in vivo; however, tumors that eventually emerged showed restoration of ZNF423 expression. ZNF423 is developmentally restricted in the peripheral nerve lineage yet elevated in MPNST, with single-cell analyses of patient nerve sheath tumors revealing localized expression restricted to malignant cells rather than SOX10-positive benign tumor cells. These data identify ZNF423 as a putative malignant biomarker, a potential dependency in NF1-MPNST, and nominate downstream stress and genome maintenance pathways as cooperative therapeutic vulnerabilities. STATEMENT OF SIGNIFICANCEZNF423 is a developmentally restricted transcription factor selectively reactivated in NF1-associated malignant peripheral nerve sheath tumors. Targeted ablation triggers the integrated stress response, impairs DNA synthesis, sensitizes cells to chemotherapy and PARP inhibition, and restricts in vivo growth. ZNF423 represents a candidate biomarker and therapeutic vulnerability in this aggressive sarcoma.

cancer biology↗

bioRxiv2023

Gemcitabine plus nab-paclitaxel preserves skeletal and cardiac mass and function in a murine model of pancreatic cancer cachexia

More than 85% of patients with pancreatic ductal adenocarcinoma (PDAC) suffer from cachexia, a debilitating syndrome characterized by the loss of muscle and fat and remains an unmet medical need. While chemotherapy remains an effective treatment option, it can also induce weight and muscle loss in patients with cancer. Gemcitabine combined with nab paclitaxel (GnP) is a first line treatment option for patients with PDAC but GnPs effect on cachexia has not been comprehensively investigated. We interrogated the effects of GnP in a murine model of pancreatic cancer cachexia. Mice were orthotopically implanted with the cachexia inducing pancreatic cell line (KPC) and were administered GnP or vehicle. The controls underwent sham surgery. We defined GnP effects on cachexia and tumor burden by evaluating muscle and cardiac mass and function, fat mass, bone morphometry, and hematology measurements. We completed RNA sequencing and deep proteome profiling in skeletal and cardiac muscle. KPC+GnP reduced tumor burden over 50% and increased survival compared to KPC. KPC vehicle group had more than 15% muscle mass loss and decreased left ventricular mass, this was not present in KPC+GnP when compared to controls. RNA Seq and deep proteomics analyses suggested that muscle and cardiac dysfunction pathways activated in KPC group were either reversed or decreased in KPC+GnP. In all, our data suggests that GnP protects against muscle and cardiac wasting in an experimental model of PDAC cachexia. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=98 SRC="FIGDIR/small/536434v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@1d394f7org.highwire.dtl.DTLVardef@1d8fdaforg.highwire.dtl.DTLVardef@f709d4org.highwire.dtl.DTLVardef@a668e0_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG

cancer biology↗

bioRxiv2023

A novel triptolide analog downregulates NF-κB and induces mitochondrial apoptosis pathways in human pancreatic cancer

BackgroundPancreatic cancer is the seventh leading cause of cancer-related death worldwide, and despite advancements in disease management, the 5-year survival rates stands at only 9%. Triptolides have potent anti-tumor activity against different types of cancers, including pancreatic cancer, however poor solubility and toxicity limit their translation into clinical use. MethodsWe synthesized a novel pro-drug of triptolide, (E)-19-[(1-benzoyloxy-1-phenyl)-methylidene]-Triptolide (CK21), and formulated into an emulsion for in vitro and in vivo testing in rats and mice, and using human pancreatic cancer cell lines and patient-derived pancreatic tumor organoids. A time-course transcriptomic profiling of tumor organoids treated with CK21 in vitro was conducted to define its mechanism of action, as well as transcriptomic profiling at a single time point post-CK21 administration in vivo. FindingsIntravenous administration of emulsified CK21 resulted in the stable release of triptolide, and potent anti-proliferative effects on human pancreatic cancer cell lines and patient-derived pancreatic tumor organoids in vitro, and with minimal toxicity in vivo. Time course transcriptomic profiling of tumor organoids treated with CK21 in vitro revealed <10 differentially expressed genes (DEGs) at 3 h and [~]8,000 DEGs at 12 h. Overall inhibition of general RNA transcription was observed, and Ingenuity pathway analysis together with functional cellular assays confirmed inhibition of the NF-{kappa}B pathway, increased oxidative phosphorylation and mitochondrial dysfunction, leading ultimately to increased reactive oxygen species (ROS) production, reduced B-cell-lymphoma protein 2 (BCL2) expression, and mitochondrial-mediated tumor cell apoptosis. InterpretationCK21 is a novel pro-drug of triptolide that exerts potent anti-proliferative effects on human pancreatic tumors by inhibiting the NF-{kappa}B pathway, leading ultimately to mitochondrial-mediated tumor cell apoptosis. FundingThe study of the anti-tumor efficacy of CK21 supported in part by a research grant from Cinkate Pharmaceutical Corp; the funders had no role in the study design, interpretation or decision to publish. Patient-derived pancreatic tumor organoids were a generous gift from the Organoid and Primary Culture Research Core at University of Chicago.

pharmacology and toxicology↗

bioRxiv2022

Cancer-associated fibroblast-derived ROR2 induces WNT/PCP activation and polarized migration in receiving gastric cancer cells.

Bone marrow-derived mesenchymal stem cells and cancer-associated fibroblasts in the tumor-stromal environment have been linked to cancer progression in many studies. These fibroblasts provide signaling factors to the tumor cells that promote proliferation, survival, invasion, and metastasis. One signaling pathway influencing tumor cell behavior is the WNT/Planar Cell Polarity (PCP) signaling in gastric cancer. Here, we show that the gastric tumor cell line, AGS, can respond to the PCP ligand WNT5A, however, express a very low level of the bona-fide WNT/PCP receptor, ROR2. At the same time, we find that CAF display long filopodia and had significantly higher levels of ROR2 than normal gastric fibroblasts. By high-resolution imaging, we observe a direct, cytoneme-mediated transfer of a complex containing ROR2 and WNT5A from CAF to the gastric cancer cells. The amount of ROR2 transferred correlated with JNK signaling in receiving cells, showing a direct requirement for receptor transfer. Co-culture of AGS with CAF expressing a dominant-negative form of ROR2 exhibited reduced actin polarization and migration compared to wild-type CAF. Furthermore, induction of migration via paracrine ROR2 transfer was observed in a zebrafish in vivo model. These unexpected findings demonstrate a fresh role in the direct transfer of a Wnt receptor from a signal-producing cell to a receiving cell and explain the mechanism by which gastric cancer cells expressing low levels of ROR2 can respond to a WNT5A-high tumor microenvironment.

cancer biology↗

bioRxiv2018

LTMG (Left truncated mixture Gaussian) based modeling of transcriptional regulatory heterogeneities in single cell RNA-seq data - a perspective from the kinetics of mRNA metabolism

A key challenge in modeling single-cell RNA-seq (scRNA-seq) data is to capture the diverse gene expression states regulated by different transcriptional regulatory inputs across single cells, which is further complicated by a large number of observed zero and low expressions. We developed a left truncated mixture Gaussian (LTMG) model that stems from the kinetic relationships between the transcriptional regulatory inputs and metabolism of mRNA and gene expression abundance in a cell. LTMG infers the expression multi-modalities across single cell entities, representing a genes diverse expression states; meanwhile the dropouts and low expressions are treated as left truncated, specifically representing an expression state that is under suppression. We demonstrated that LTMG has significantly better goodness of fitting on an extensive number of single-cell data sets, comparing to three other state of the art models. In addition, our systems kinetic approach of handling the low and zero expressions and correctness of the identified multimodality are validated on several independent experimental data sets. Application on data of complex tissues demonstrated the capability of LTMG in extracting varied expression states specific to cell types or cell functions. Based on LTMG, a differential gene expression test and a co-regulation module identification method, namely LTMG-DGE and LTMG-GCR, are further developed. We experimentally validated that LTMG-DGE is equipped with higher sensitivity and specificity in detecting differentially expressed genes, compared with other five popular methods, and that LTMG-GCR is capable to retrieve the gene co-regulation modules corresponding to perturbed transcriptional regulations. A user-friendly R package with all the analysis power is available at https://github.com/zy26/LTMGSCA.

bioinformatics↗