Enzymatic suicide inactivation, a route of permanent enzyme inhibition, is the mechanism of action for a wide array of pharmaceuticals. Here, we developed the first nanosensor that selectively reports the suicide inactivation pathway of an enzyme. The sensor is based on modulation of the near-infrared fluorescence of an enzyme-bound carbon nanotube. The nanosensor responded selectively to substrate-mediated suicide inactivation of the tyrosinase enzyme via bathochromic shifting of the nanotube emission wavelength. Mechanistic investigations revealed that singlet oxygen generated by the suicide inactivation pathway induced the response. We used the nanosensor to quantify the degree of enzymatic inactivation by measuring response rates to known small molecule tyrosinase modulators. This work resulted in a new capability of interrogating a specific route of enzymatic death. Potential applications include drug screening and hit-validation for compounds that elicit or inhibit enzymatic inactivation, and single-molecule measurements to assess population heterogeneity in enzyme activity.

Cisplatin-induced acute kidney injury (CI-AKI) is a significant co-morbidity of chemotherapeutic regimens. While this condition is associated with substantially lower survival and increased economic burden, there is no pharmacological agent to effectively treat CI-AKI. The disease is hallmarked by acute tubular necrosis of the proximal tubular epithelial cells primarily due to increased oxidative stress. We investigated a drug delivery strategy to improve the pharmacokinetics of an approved therapy that does not normally demonstrate appreciable efficacy in CI-AKI, as a preventive intervention. In prior work, we developed a kidney-selective mesoscale nanoparticle (MNP) that targets the renal proximal tubular epithelium. Here, we found that the nanoparticles target the kidneys in a mouse model of CI-AKI with significant damage. We evaluated MNPs loaded with the reactive oxygen species scavenger edaravone, currently used to treat stroke and ALS. We found a marked and significant therapeutic benefit with edaravone-loaded MNPs, including improved renal function, which we demonstrated was likely due to a decrease in tubular epithelial cell damage and death imparted by the specific delivery of edaravone. The results suggest that renal-selective edaravone delivery holds potential for the prevention of acute kidney injury among patients undergoing cisplatin-based chemotherapy.

Recent multiplexed protein imaging technologies make it possible to characterize cells, their spatial organization, and interactions within microenvironments at unprecedented resolution. Although observational data can reveal spatial associations, it does not allow users to infer biologically causative relationships and interactions between cells. To address this challenge, we develop a generative model that allows users to test hypotheses about the effect of cell-cell interactions on protein expression through in silico perturbation. Our Cell-Cell Interaction GAN (CCIGAN) model employs a generative adversarial network (GAN) architecture to generate biologically realistic multiplexed cell images from semantic cell segmentations. Our approach is unique in considering all imaging channels simultaneously, and we show that it successfully captures known tumor-immune cell interactions missed by other state-of-the-art GAN models, and yields biological insights without requiring in vivo manipulation. CCIGAN accepts data from multiple imaging technologies and can infer interactions from single images in any health or disease context.

Cisplatin-induced acute kidney injury (CI-AKI) is a significant co-morbidity of chemotherapeutic regimens. While this condition is associated with substantially lower survival and increased economic burden, there is no pharmacological agent to effectively treat CI-AKI. The disease is hallmarked by acute tubular necrosis of the proximal tubular epithelial cells primarily due to increased oxidative stress. In our prior work, we developed a highly-selective kidneytargeted mesoscale nanoparticle (MNP) that accumulates primarily in the renal proximal tubular epithelial cells while exhibiting no toxicity. Here, we found that MNPs exhibit renal-selective targeting in multiple mouse models of tumor growth with virtually no tumor accumulation. We then evaluated the therapeutic efficacy of MNPs loaded with the reactive oxygen species scavenger edaravone in a mouse model of CI-AKI. We found a marked and significant therapeutic effect with this approach as compared to free drug or empty control MNPs, including improved renal function, histology, and diminution of oxidative stress. These results indicated that renal-selective MNP edaravone delivery holds substantial potential in the treatment of acute kidney injury among patients undergoing cisplatin-based chemotherapy. Acute kidney injury (AKI) is a common clinical condition associated with significant morbidity and mortality regardless of etiology or setting. AKI affects millions of individual patients and has a large socioeconomic impact, including longer hospital stay and higher costs. In the US alone, it is estimated that the annual costs related to AKI are up to $24 billion 1 . The incidence of AKI is increasing at a rapid pace 2,3 , which is attributable to several factors including shifts in demographics, severity of underlying diseases, and expansion of invasive and complex medical procedures 4,5 . AKI can result from a variety of insults including volume depletion, septicemia, hypotension, and commonly used drugs including antibiotics and chemotherapeutic agents.Cisplatin is a widely used chemotherapy in the treatment of a variety of cancers including ovarian, head and neck, bladder, testicular, and lung, among others 6,7 . A significant side effect of cisplatin therapy is the occurrence of AKI in approximately 33% of patients 8,9 . Indeed, it has been reported that about 20% of all AKI incidences are caused by cisplatin 7,10 . The development of AKI in these patients can result in the interruption of chemotherapy or a change to less effective chemotherapies 8,9 . There is therefore a critical need to develop novel strategies to prevent or treat AKI induced by cisplatin. This would also have a direct impact on the oncologic outcomes of these patients whose treatment otherwise cannot be completed, or other less-effective chemotherapeutic agents must be used 11 .There has been significant overall progress in our understanding of the epidemiology, pathophysiology and outcomes of AKI. Despite such substantial advances, almost no meaningful progress has been made in the ...

Many traditional nanoparticle delivery mechanisms require the use of an inert vehicle to deliver single therapeutic payloads. Here, we describe a novel, dual-therapeutic, self-assembled nanoparticle class wherein both the payload and encapsulating vehicle may potentiate anti-neoplastic effects. The nanoparticles consist of photoactive porphyrin dyes encapsulating small molecule drugs. We screened 9 porphyrins with 27 small molecules for the formation of porphyrin-drug nanoparticles; a total of 243 nanoparticle candidates, of which 25 formed nanoparticles as dictated by pre-determined cutoffs for size, polydispersity, and porphyrin/drug concentrations. Logistic regression based on formation data and molecular descriptors suggested that the presence of electronegative groups positively influenced nanoparticle formation. Chemical inhibition of various uptake pathways in endothelial cells indicated that the uptake of these porphyrin-drug nanoparticles is largely mediated by clathrin and macropinocytosis. Stability testing demonstrated that porphyrin-drug nanoparticles remained stable at 37°C for at least 6 hrs. This work outlines the synthesis and characterization of a new class of porphyrin nanoparticles with the capacity to deliver targeted therapy. Furthermore, the simplicity of the self-assembly process highlights the potential for this novel nanoparticle paradigm to be easily tested in disease models. Citation Format: Justin M. Cheung, Hanan Baker, Daniel Li, Daniel Stor, Daniel A. Heller. Drug-loaded porphyrin nanoparticles as a platform for targeted and photodynamic combination therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1719.