Stephanie A. Montgomery

Biological targeting is crucial for effective cancer treatment with reduced toxicity but is limited by the availability of tumor surface markers. To overcome this, we developed a nanoparticle-based (NP-based), tumor-specific surface marker–independent (TRACER) targeting approach. Utilizing the unique biodistribution properties of NPs, we encapsulated Ac ₄ ManNAz (Maz) to selectively label tumors with azide-reactive groups. Surprisingly, while NP-delivered Maz was cleared by the liver, it did not label macrophages, potentially reducing off-target effects. To exploit this tumor-specific labeling, we functionalized anti–4-1BB Abs with dibenzocyclooctyne to target azide-labeled tumor cells and activate the immune response. In syngeneic B16F10 melanoma and orthotopic 4T1 breast cancer models, TRACER enhanced the therapeutic efficacy of anti–4-1BB, increasing the median survival time. Immunofluorescence analyses revealed increased tumor infiltration of CD8 ⁺ T and NK cells with TRACER. Importantly, TRACER reduced the hepatotoxicity associated with anti–4-1BB, resulting in normal serum ALT and AST levels and decreased CD8 ⁺ T cell infiltration into the liver. Quantitative analysis confirmed a 4.5-fold higher tumor-to-liver ratio of anti–4-1BB accumulation with TRACER compared with conventional anti–4-1BB Abs. Our work provides a promising approach for developing targeted cancer therapies that circumvent limitations imposed by the paucity of tumor-specific markers, potentially improving efficacy and reducing off-target effects to overcome the liver toxicity associated with anti–4-1BB.

Despite the wide availability of several safe and effective vaccines that prevent severe COVID-19, the persistent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that can evade vaccine-elicited immunity remains a global health concern. In addition, the emergence of SARS-CoV-2 VOCs that can evade therapeutic monoclonal antibodies underscores the need for additional, variant-resistant treatment strategies. Here, we characterize the antiviral activity of GS-5245, obeldesivir (ODV), an oral prodrug of the parent nucleoside GS-441524, which targets the highly conserved viral RNA-dependent RNA polymerase (RdRp). We show that GS-5245 is broadly potent in vitro against alphacoronavirus HCoV-NL63, SARS-CoV, SARS-CoV–related bat-CoV RsSHC014, Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV-2 WA/1, and the highly transmissible SARS-CoV-2 BA.1 Omicron variant. Moreover, in mouse models of SARS-CoV, SARS-CoV-2 (WA/1 and Omicron B1.1.529), MERS-CoV, and bat-CoV RsSHC014 pathogenesis, we observed a dose-dependent reduction in viral replication, body weight loss, acute lung injury, and pulmonary function with GS-5245 therapy. Last, we demonstrate that a combination of GS-5245 and main protease (M ^pro ) inhibitor nirmatrelvir improved outcomes in vivo against SARS-CoV-2 compared with the single agents. Together, our data support the clinical evaluation of GS-5245 against coronaviruses that cause or have the potential to cause human disease.

Despite the wide availability of several safe and effective vaccines that can prevent severe COVID-19 disease, the emergence of SARS-CoV-2 variants of concern (VOC) that can partially evade vaccine immunity remains a global health concern. In addition, the emergence of highly mutated and neutralization-resistant SARS-CoV-2 VOCs such as BA.1 and BA.5 that can partially or fully evade ( 1 ) many therapeutic monoclonal antibodies in clinical use underlines the need for additional effective treatment strategies. Here, we characterize the antiviral activity of GS-5245, Obeldesivir (ODV), an oral prodrug of the parent nucleoside GS-441524, which targets the highly conserved RNA-dependent viral RNA polymerase (RdRp). Importantly, we show that GS-5245 is broadly potent in vitro against alphacoronavirus HCoV-NL63, severe acute respiratory syndrome coronavirus (SARS-CoV), SARS-CoV-related Bat-CoV RsSHC014, Middle East Respiratory Syndrome coronavirus (MERS-CoV), SARS-CoV-2 WA/1, and the highly transmissible SARS-CoV-2 BA.1 Omicron variant in vitro and highly effective as antiviral therapy in mouse models of SARS-CoV, SARS-CoV-2 (WA/1), MERS-CoV and Bat-CoV RsSHC014 pathogenesis. In all these models of divergent coronaviruses, we observed protection and/or significant reduction of disease metrics such as weight loss, lung viral replication, acute lung injury, and degradation in pulmonary function in GS-5245-treated mice compared to vehicle controls. Finally, we demonstrate that GS-5245 in combination with the main protease (M ^pro ) inhibitor nirmatrelvir had increased efficacy in vivo against SARS-CoV-2 compared to each single agent. Altogether, our data supports the continuing clinical evaluation of GS-5245 in humans infected with COVID-19, including as part of a combination antiviral therapy, especially in populations with the most urgent need for more efficacious and durable interventions.

Giardia lamblia (Giardia) is among the most common intestinal pathogens in children in low- and middle-income countries (LMICs). Although Giardia associates with early-life linear growth restriction, mechanistic explanations for Giardia-associated growth impairments remain elusive. Unlike other intestinal pathogens associated with constrained linear growth that cause intestinal or systemic inflammation or both, Giardia seldom associates with chronic inflammation in these children. Here we leverage the MAL-ED longitudinal birth cohort and a model of Giardia mono-association in gnotobiotic and immunodeficient mice to propose an alternative pathogenesis of this parasite. In children, Giardia results in linear growth deficits and gut permeability that are dose-dependent and independent of intestinal markers of inflammation. The estimates of these findings vary between children in different MAL-ED sites. In a representative site, where Giardia associates with growth restriction, infected children demonstrate broad amino acid deficiencies, and overproduction of specific phenolic acids, byproducts of intestinal bacterial amino acid metabolism. Gnotobiotic mice require specific nutritional and environmental conditions to recapitulate these findings, and immunodeficient mice confirm a pathway independent of chronic T/B cell inflammation. Taken together, we propose a new paradigm that Giardia-mediated growth faltering is contingent upon a convergence of this intestinal protozoa with nutritional and intestinal bacterial factors.

The reversibility of the procancer effects of obesity was interrogated in formerly obese C57BL/6 mice that lost weight via a nonrestricted low-fat diet (LFD) or 3 distinct calorie-restricted (CR) regimens (low-fat CR, Mediterranean-style CR, or intermittent CR). These mice, along with continuously obese mice and lean control mice, were orthotopically injected with E0771 cells, a mouse model of triple-negative breast cancer. Tumor weight, systemic cytokines, and incidence of lung metastases were elevated in the continuously obese and nonrestricted LFD mice relative to the 3 CR groups. Gene expression differed between the obese and all CR groups, but not the nonrestricted LFD group, for numerous tumoral genes associated with epithelial-to-mesenchymal transition as well as several genes in the normal mammary tissue associated with hypoxia, reactive oxygen species production, and p53 signaling. A high degree of concordance existed between differentially expressed mammary tissue genes from obese versus all CR mice and a microarray dataset from overweight/obese women randomized to either no intervention or a CR diet. Assessment of differentially methylated regions in mouse mammary tissues revealed that obesity, relative to the 4 weight loss groups, was associated with significant DNA hypermethylation. However, the anticancer effects of the CR interventions were independent of their ability to reverse obesity-associated mammary epigenetic reprogramming. Taken together, these preclinical data showing that the procancer effects of obesity are reversible by various forms of CR diets strongly support translational exploration of restricted dietary patterns for reducing the burden of obesity-associated cancers.Prevention Relevance:Obesity is an established risk and progression factor for triple-negative breast cancer (TNBC). Given rising global rates of obesity and TNBC, strategies to reduce the burden of obesity-driven TNBC are urgently needed. We report the genomic, epigenetic, and procancer effects of obesity are reversible by various calorie restriction regimens.

Supplementary Table from Reversing the Genomic, Epigenetic, and Triple-Negative Breast Cancer–Enhancing Effects of Obesity

Supplementary Figure from Reversing the Genomic, Epigenetic, and Triple-Negative Breast Cancer–Enhancing Effects of Obesity