In recent decades, dysregulation of proteases and atypical proteolysis have become increasingly recognized as important hallmarks of cancer, driving community-wide efforts to explore the proteolytic ...landscape of oncologic disease. With more than 100 proteases currently associated with different aspects of cancer development and progression, there is a clear impetus to harness their potential in the context of oncology. Advances in the protease field have yielded technologies enabling sensitive protease detection in various settings, paving the way towards diagnostic profiling of disease-related protease activity patterns. Methods including activity-based probes and substrates, antibodies, and various nanosystems that generate reporter signals, i.e., for PET or MRI, after interaction with the target protease have shown potential for clinical translation. Nevertheless, these technologies are costly, not easily multiplexed, and require advanced imaging technologies. While the current clinical applications of protease-responsive technologies in oncologic settings are still limited, emerging technologies and protease sensors are poised to enable comprehensive exploration of the tumor proteolytic landscape as a diagnostic and therapeutic frontier. This review aims to give an overview of the most relevant classes of proteases as indicators for tumor diagnosis, current approaches to detect and monitor their activity in vivo, and associated therapeutic applications.
Rotating magnetic fields enable biomedical microrobots to overcome physiological barriers and promote extravasation and accumulation in tumors. Nevertheless, targeting deeply situated tumors requires ...suppression of off-target actuation in healthy tissue. Here, we investigate a control strategy for applying spatially selective torque density to microrobots by combining rotating fields with magnetostatic selection fields. Taking magnetotactic bacteria as diffuse torque-based actuators, we numerically model off-target torque suppression, indicating the feasibility of centimeter to millimeter resolution for human applications. We study focal torque application in vitro, observing off-target suppression of actuation-dependent effects such as colonization of bacteria in tumor spheroids. We then design and construct a mouse-scale torque-focusing apparatus capable of maneuvering the focal point. Applying this system to a mouse tumor model increased accumulation of intravenously injected bacteria within tumors receiving focused actuation compared to non-actuated or globally actuated groups. This control scheme combines the advantages of torque-based actuation with spatial targeting.
Local soft tissue status (STS) guides the timing for definitive surgical treatment strategies of fracture fixation around the ankle joint. The aim of this study was to assess different types of new ...technical devices in relation to the surgical treatment in closed ankle and pilon fractures.
This study was designed as a cohort study. Adult patients admitted between February 1, 2019 and December 31, 2020 presenting with closed ankle fracture requiring surgical treatment were eligible. The exclusion criteria were previous injuries to the lower extremity, acute deep venous thrombosis, skin diseases, and delayed presentation (admission >24 hours after injury). Moderate-energy trauma includes injuries sustained during team sports, biking, and running. The primary outcome was the assessment of the degree of soft tissue involvement following closed fractures by comparing different techniques focusing on the ankle region and including ankle and pilon fractures. The variables of interest included the circumference of soft tissue swelling around the ankle, determined within a 5-mm range in the area of the medial and lateral malleolus and the bone-skin distance on a plain radiograph, determined by the largest distance from the malleolus to the border of the soft-tissue shadow. STS assessment included optical measures of local perfusion (O2C, Lea Inc. Germany) and tactile measures of mechanical characteristics (Myoton® tensiometer AS, Estonia). Measurements of Group Temp (temporary stabilization) and Group Def (definitive surgery) were taken on admission and prior to the treatment strategy decision. The contralateral non-injured ankle served as a control. The quality of assessment tools was quantified by calculating the smallest detectable change (SDC).
In total, 38 patients with a mean age of 40.4 (SD 17.8) years were included. The SDC was 3.2% (95%CI 2.5 to 3.8) for local blood flow and 1.1% (95%CI 0.4 to 1.7) for soft tissue stiffness. The circumference of the injured area at admission was significantly higher than that of the healthy site (28.2 SD 3.4 cm versus 23.9 SD 2.4 cm, p < 0.001). The local perfusion (blood flow 107.5 (SD 40.79 A.U. vs. 80.1 SD 13.8 A.U., p = 0.009), and local dynamic stiffness of the skin (668.1 (SD 148.0) N/m vs 449.5 (SD 87.7) N/m, p < 0.001) were significantly higher at the injured site. In Group Temp, the local blood flow was significantly higher when compared with Group Def (109.6 SD 39.8 vs. 94.5 SD 13.0, p = 0.023). The dynamic stiffness of the soft tissue was significantly higher in Group Temp (679.4 N/m SD 147.0 N/m vs. 573.0 N/m (SD 93.8) N/m, p < 0.001). The physical properties of STS were comparable among the fracture types. None of the included patients had local soft tissue complications.
Closed fractures of the ankle and the pilon are associated with an increase in local circulation and local soft tissue stiffness and tension. These changes of the STS following injury can be quantified in a standardized and reproducible manner.
IntroductionLocal soft tissue status (STS) guides the timing for definitive surgical treatment strategies of fracture fixation around the ankle joint. The aim of this study was to assess different ...types of new technical devices in relation to the surgical treatment in closed ankle and pilon fractures.MethodsThis study was designed as a cohort study. Adult patients admitted between February 1, 2019 and December 31, 2020 presenting with closed ankle fracture requiring surgical treatment were eligible. The exclusion criteria were previous injuries to the lower extremity, acute deep venous thrombosis, skin diseases, and delayed presentation (admission >24 hours after injury). Moderate-energy trauma includes injuries sustained during team sports, biking, and running. The primary outcome was the assessment of the degree of soft tissue involvement following closed fractures by comparing different techniques focusing on the ankle region and including ankle and pilon fractures. The variables of interest included the circumference of soft tissue swelling around the ankle, determined within a 5-mm range in the area of the medial and lateral malleolus and the bone-skin distance on a plain radiograph, determined by the largest distance from the malleolus to the border of the soft-tissue shadow. STS assessment included optical measures of local perfusion (O2C, Lea Inc. Germany) and tactile measures of mechanical characteristics (Myoton® tensiometer AS, Estonia). Measurements of Group Temp (temporary stabilization) and Group Def (definitive surgery) were taken on admission and prior to the treatment strategy decision. The contralateral non-injured ankle served as a control. The quality of assessment tools was quantified by calculating the smallest detectable change (SDC).ResultsIn total, 38 patients with a mean age of 40.4 (SD 17.8) years were included. The SDC was 3.2% (95%CI 2.5 to 3.8) for local blood flow and 1.1% (95%CI 0.4 to 1.7) for soft tissue stiffness. The circumference of the injured area at admission was significantly higher than that of the healthy site (28.2 SD 3.4 cm versus 23.9 SD 2.4 cm, p < 0.001). The local perfusion (blood flow 107.5 (SD 40.79 A.U. vs. 80.1 SD 13.8 A.U., p = 0.009), and local dynamic stiffness of the skin (668.1 (SD 148.0) N/m vs 449.5 (SD 87.7) N/m, p < 0.001) were significantly higher at the injured site. In Group Temp, the local blood flow was significantly higher when compared with Group Def (109.6 SD 39.8 vs. 94.5 SD 13.0, p = 0.023). The dynamic stiffness of the soft tissue was significantly higher in Group Temp (679.4 N/m SD 147.0 N/m vs. 573.0 N/m (SD 93.8) N/m, p < 0.001). The physical properties of STS were comparable among the fracture types. None of the included patients had local soft tissue complications.ConclusionClosed fractures of the ankle and the pilon are associated with an increase in local circulation and local soft tissue stiffness and tension. These changes of the STS following injury can be quantified in a standardized and reproducible manner.
Interest has grown in harnessing biological agents for cancer treatment as dynamic vectors with enhanced tumor targeting. While bacterial traits such as proliferation in tumors, modulation of an ...immune response, and local secretion of toxins have been well studied, less is known about bacteria as competitors for nutrients. Here, we investigated the use of a bacterial strain as a living iron chelator, competing for this nutrient vital to tumor growth and progression. We established an in vitro co-culture system consisting of the magnetotactic strain
AMB-1 incubated under hypoxic conditions with human melanoma cells. Siderophore production by 10
AMB-1/mL in human transferrin (Tf)-supplemented media was quantified and found to be equivalent to a concentration of 3.78 µM ± 0.117 µM deferoxamine (DFO), a potent drug used in iron chelation therapy. Our experiments revealed an increased expression of transferrin receptor 1 (TfR1) and a significant decrease of cancer cell viability, indicating the bacteria's ability to alter iron homeostasis in human melanoma cells. Our results show the potential of a bacterial strain acting as a self-replicating iron-chelating agent, which could serve as an additional mechanism reinforcing current bacterial cancer therapies.
Targeted cancer therapies require a precise determination of the underlying biological processes driving tumorigenesis within the complex tumor microenvironment. Therefore, new diagnostic tools that ...capture the molecular activity at the disease site in vivo are needed to better understand tumor behavior and ultimately maximize therapeutic responses. Matrix metalloproteinases (MMPs) drive multiple aspects of tumorigenesis, and their activity can be monitored using engineered peptide substrates as protease-specific probes. To identify tumor specific activity profiles, local sampling of the tumor microenvironment is necessary, such as through remote control of probes, which are only activated at the tumor site. Alternating magnetic fields (AMFs) provide an attractive option to remotely apply local triggering signals because they penetrate deep into the body and are not likely to interfere with biological processes due to the weak magnetic properties of tissue. Here, we report the design and evaluation of a protease-activity nanosensor that can be remotely activated at the site of disease via an AMF at 515 kHz and 15 kA/m. Our nanosensor was composed of thermosensitive liposomes containing functionalized protease substrates that were unveiled at the target site by remotely triggered heat dissipation of coencapsulated magnetic nanoparticles (MNPs). This nanosensor was combined with a unique detection assay to quantify the amount of cleaved substrates in the urine. We applied this spatiotemporally controlled system to determine tumor protease activity in vivo and identified differences in substrate cleavage profiles between two mouse models of human colorectal cancer.
Engineering Cell‐Based Systems for Smart Cancer Therapy Mirkhani, Nima; Gwisai, Tinotenda; Schuerle, Simone
Advanced intelligent systems,
January 2022, 2022-01-00, 20220101, 2022-01-01, Volume:
4, Issue:
1
Journal Article
Peer reviewed
Open access
Due to the difficulty of targeting systemically delivered therapeutics for cancer, interest has grown in exploiting biological agents to enhance tumor accumulation and mediate localized drug ...delivery. Equipped with onboard sensing and active motility, some cells respond to specific cues of the tumor microenvironment, making them ideal candidates for smart cancer therapy. Herein, recent progress and developments are presented on the use of four of the most promising cell‐based systems for tumor targeting and drug delivery—immune cells, stem cells, platelets, and bacteria. Strategies to further enhance specificity at the tissue and cell level are discussed, including genetic engineering, chemical cell surface modification, and the use of external physical stimuli. With crucial ongoing efforts addressing the safety and efficacy of living intelligent therapeutics, a new era of cancer medicine is on the horizon.
Immune cells, stem cells, platelets, and bacteria possess unique attributes making them ideal candidates for smart cancer therapy. Equipped with onboard sensing and active motility, these cells can home to tumors where they release therapeutic cargo. External stimuli, such as magnetic fields, as well as cell surface modifications and genetic engineering can further enhance their safety and efficacy.
Magnetically driven soft actuators are unique because they are fast, remote‐controlled, conformal to rigid objects, and safe to interact with humans. Despite these multiple functionalities, a broader ...utilization of such actuators is hindered by the high cost and equipment‐intensive nature of currently available manufacturing processes. Herein, a simple fabrication route for magneto‐responsive soft actuators is described using cost‐effective and broadly available raw materials and equipment. The method utilizes castable silicone resins that are loaded with magnetic particles and subsequently magnetized under an external magnetic field. The experimental investigation of silicone‐based composites prepared with particles of distinct chemistries, sizes, and morphologies enables the identification of the raw materials and magnetization conditions required for the process. This leads to functional soft actuators with programmable magnetic patterns that are capable of performing pick‐and‐place, lifting, catching, and moving tasks under the remote action of an external magnetic field. By removing manufacturing hurdles associated with costly raw materials and equipment, the proposed approach is expected to facilitate the design, implementation, and exploitation of the unique functionalities of magneto‐controlled soft actuators in a wider number of applications.
Silicone‐based soft actuators that are able to quickly grasp, lift, or pick‐and‐place objects under the action of an external magnetic field can be manufactured using widely available magnets and molding tools. This cost‐effective manufacturing route relies on the formulation of commercial silicone resins containing oxide particles with specific magnetic properties.
Alterations of blood flow patterns strongly correlate with arterial wall diseases such as atherosclerosis and aneurysm. Here, a simple, pumpless, close‐loop, easy‐to‐replicate, and miniaturized flow ...device is introduced to concurrently expose 3D engineered vascular smooth muscle tissues to high‐velocity pulsatile flow versus low‐velocity disturbed flow conditions. Two flow regimes are distinguished, one that promotes elastin and impairs collagen I assembly, while the other impairs elastin and promotes collagen assembly. This latter extracellular matrix (ECM) composition shares characteristics with aneurysmal or atherosclerotic tissue phenotypes, thus recapitulating crucial hallmarks of flow‐induced tissue morphogenesis in vessel walls. It is shown that the mRNA levels of ECM of collagens and elastin are not affected by the differential flow conditions. Instead, the differential gene expression of matrix metalloproteinase (MMP) and their inhibitors (TIMPs) is flow‐dependent, and thus drives the alterations in ECM composition. In further support, treatment with doxycycline, an MMP inhibitor and a clinically used drug to treat vascular diseases, halts the effect of low‐velocity flow on the ECM remodeling. This illustrates how the platform can be exploited for drug efficacy studies by providing crucial mechanistic insights into how different therapeutic interventions may affect tissue growth and ECM assembly.
Alterations of hemodynamics are associated with vascular wall diseases. A simple, pumpless, close‐loop, easy‐to‐replicate flow device to engineer de novo‐grown disease‐like extracellular matrix of vascular wall tissues is proposed. Mechanistic insights of a clinically practiced matrix metalloproteinase inhibitor used to treat aneurysm and atherosclerosis, and on how the stage of the disease might affect the efficacy of the treatment are gained.
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