Biology subjects

Piwnica-Worms, D.

Publications and source records attributed to Piwnica-Worms, D..

5 recordsLinked to original sources

bioRxiv2025

Targeted Molecular MRI of Colorectal Cancer by Antibody Functionalized Hyperpolarized Silicon Particles

The development of non-invasive, non-ionizing sensitive molecular targeting approaches to detect colorectal cancer (CRC) lesions is warranted to improve high risk patient outcomes. Hyperpolarized silicon nanoparticles and microparticles are potentially well-suited to act as targeted molecular imaging agents because of their overall biocompatibility and long-lasting enhanced magnetic resonance imaging (MRI) signals. In this study, dynamic nuclear polarization was performed on silicon particles functionalized with an antibody to Mucin-1 (MUC1), a surface mucin glycoprotein aberrantly expressed in CRC. Antibody conjugation to the particle surface did not affect 29Si hyperpolarization characteristics. Similarly, conjugation and the dynamic nuclear polarization process did not adversely affect the affinity of the targeting antibody. In vivo MRI scans performed 10-15 minutes after luminal administration of targeted hyperpolarized particles into human MUC1-expressing orthotopic CRC mouse models showed that particles actively targeted tumor sites. These results were supported by chemical and biological controls and blocking experiments as well as correlative immunohistochemical analysis. These surface-functionalized silicon particles are under development as a platform technology that will allow non-invasive molecular targeting of CRC using hyperpolarized MRI. Single Sentence SummaryTargeted molecular MR imaging of colorectal cancer by hyperpolarized silicon particles functionalized with mucin 1 antibody.

cancer biology↗

bioRxiv2024

Anti-Cancer Immune Priming with Beta-Radioligand Therapy and Isoform-Selective Targeting of 4Ig-B7-H3

Radioligand therapy (RLT), a re-emerging oncologic strategy using molecularly-targeted therapeutic radioisotopes, clinically reduces tumor burden and enhances survival for select patients with otherwise unresponsive advanced prostate cancer and neuroendocrine tumors. Developing new approaches to next generation targets and a better understanding of systemic immune effects could broaden the impact of RLT. Aside from contributions to immune checkpoint, B7-H3 (CD276) is an attractive oncologic target because of its widespread and high differential expression across a variety of solid tumors compared to normal tissues. However, B7-H3 has two isoforms: a 4Ig-B7-H3 isoform, the dominant transmembrane protein expressed on tumors and tumor immune microenvironments (TIME), and a 2Ig-B7-H3 isoform, a soluble ectodomain protein, representing a circulating, and in the context of RLT, significant shed (decoy) antigen. To enhance tumor-specific binding and circumvent confounding soluble 2Ig-B7-H3, a novel IgG2a monoclonal antibody (MIL33B) was generated with high affinity for 4Ig-B7-H3 (72 picomolar) and 8- to 18-fold selectivity over soluble 2Ig-B7-H3. Live cell fluorescence microscopy using AF594-labeled MIL33B demonstrated strong membranous localization and target specificity. PET-CT imaging with 89Zr-labeled MIL33B confirmed robust tumor-selective target binding in vivo in murine xenograft (HeLa cervical) and syngeneic tumor models (4T1 breast, B16F10 melanoma, and CT26 colorectal) expressing human 4Ig-B7-H3. As a single dose beta-emitting systemic RLT therapeutic, 90Y-labeled MIL33B (100 Ci) produced 53% long-term survival in a 4Ig-B7-H3-dependent manner in an otherwise fatal established CT26 colorectal tumor model. Immunologic analysis showed that 90Y-MIL33B RLT functioned as an immune priming event, engaging downstream CD8+ T-cell activation and inducing immunological memory in vivo, thus illustrating the potential of systemic beta-RLT to target both primary and metastatic sites. Thus, MIL33B showcases a strategy to selectively target 4Ig-B7-H3 for beta-RLT, warranting further investigation as an immune priming tactic alone or in combination for cancer therapy. Statement of significanceModest antigen expression levels, even if target tissue-selective, combined with ectodomain shedding (soluble decoy antigens) can generally hinder targeted diagnostic and therapeutic strategies, but are especially challenging for radioligand therapy, PET imaging, and in vivo diagnostics wherein high specific activity radioisotopes necessitate use of low masses of biocarrier. Binding, absorption and non-specific tissue deposition of radiolabeled biocarriers by decoy antigens can significantly misdirect systemic radiation, reducing therapeutic efficacy. An antibody development process with a focus aimed at on-target affinity for folded proteins on live cells resulted in a novel picomolar affinity antibody selectively targeting membranous 4Ig-B7-H3 over soluble decoy 2Ig-B7-H3. This antibody shows promise as a transformative systemic beta-radioligand therapy platform for immune priming applications in oncology, and potentially in cardiology, rheumatology, and autoimmunity.

cancer biology↗

bioRxiv2024

Statins inhibit onco-dimerization of the 4Ig isoform of B7-H3

B7-H3 (CD276), a member of the B7-family of immune checkpoint proteins, has been shown to have immunological and non-immunological effects promoting tumorigenesis [1, 2] and expression correlates with poor prognosis for many solid tumors, including cervical, ovarian and breast cancers [3-6]. We recently identified a tumor-cell autochthonous tumorigenic role for dimerization of the 4Ig isoform of B7-H3 (4Ig-B7-H3) [7], where 4Ig-B7-H3 dimerization in cis activated tumor-intrinsic cellular proliferation and tumorigenesis pathways, providing a novel opportunity for therapeutic intervention. Herein, a live cell split-luciferase complementation strategy was used to visualize 4Ig-B7-H3 homodimerization in a high-throughput small molecule screen (HTS) to identify modulators of this protein-protein interaction (PPI). Notably, the HTS identified several compounds that converged on lipid metabolism (including HMG-CoA reductase inhibitors, also known as statins) as significant inhibitors of 4Ig-B7-H3 dimerization (p < 0.01). In vitro and in vivo murine studies provided evidence that statin-mediated disruption of 4Ig-B7-H3 dimerization was associated with anti-tumor effects. Statin-mediated anti-cancer efficacy was selective for B7-H3-expressing tumors and retrospective analysis of clinical tumor specimens supported the hypothesis that concurrent statin use enhanced clinical outcomes for patients in a B7-H3 restricted manner. Thus, disruption of 4Ig-B7-H3 dimerization provides an unanticipated molecular mechanism linking statin use in cancer therapy and prevention with immune checkpoint.

cancer biology↗

bioRxiv2024

ATP-dependent citrate lyase Drives Left Ventricular Dysfunction by Metabolic Remodeling of the Heart

BackgroundMetabolic remodeling is a hallmark of the failing heart. Oncometabolic stress during cancer increases the activity and abundance of the ATP-dependent citrate lyase (ACL, Acly), which promotes histone acetylation and cardiac adaptation. ACL is critical for the de novo synthesis of lipids, but how these metabolic alterations contribute to cardiac structural and functional changes remains unclear. MethodsWe utilized human heart tissue samples from healthy donor hearts and patients with hypertrophic cardiomyopathy. Further, we used CRISPR/Cas9 gene editing to inactivate Acly in cardiomyocytes of MyH6-Cas9 mice. In vivo, positron emission tomography and ex vivo stable isotope tracer labeling were used to quantify metabolic flux changes in response to the loss of ACL. We conducted a multi-omics analysis using RNA-sequencing and mass spectrometry-based metabolomics and proteomics. Experimental data were integrated into computational modeling using the metabolic network CardioNet to identify significantly dysregulated metabolic processes at a systems level. ResultsHere, we show that in mice, ACL drives metabolic adaptation in the heart to sustain contractile function, histone acetylation, and lipid modulation. Notably, we show that loss of ACL increases glucose oxidation while maintaining fatty acid oxidation. Ex vivo isotope tracing experiments revealed a reduced efflux of glucose-derived citrate from the mitochondria into the cytosol, confirming that citrate is required for reductive metabolism in the heart. We demonstrate that YAP inactivation facilitates ACL deficiency. Computational flux analysis and integrative multi-omics analysis indicate that loss of ACL induces alternative isocitrate dehydrogenase 1 flux to compensate. ConclusionsThis study mechanistically delineates how cardiac metabolism compensates for suppressed citrate metabolism in response to ACL loss and uncovers metabolic vulnerabilities in the heart.

molecular biology↗

bioRxiv2021

Measuring the metabolic evolution of glioblastoma throughout tumor development, regression, and recurrence with hyperpolarized magnetic resonance

Rapid diagnosis and therapeutic monitoring of aggressive diseases such as glioblastoma can improve patient survival by providing physicians the time to optimally deliver treatment. This research tested whether metabolic imaging with hyperpolarized MRI could detect changes in tumor progression faster than conventional anatomic MRI in patient-derived glioblastoma murine models. To capture the dynamic nature of cancer metabolism, hyperpolarized MRI, NMR spectroscopy, and immunohistochemistry were performed at several time-points during tumor development, regression, and recurrence. Hyperpolarized MRI detected significant changes of metabolism throughout tumor progression whereas conventional MRI was less sensitive. This was accompanied by aberrations in amino acid and phospholipid lipid metabolism and MCT1 expression. Hyperpolarized MRI can help address clinical challenges such as identifying malignant disease prior to aggressive growth, differentiating pseudoprogression from true progression, and predicting relapse. The individual evolution of these metabolic assays as well as their correlations with one another provides context for further academic research.

biophysics↗