Drivers and constraints to environmental sustainability in UK-based biobanking: balancing resource efficiency and future value.

BACKGROUND: Biobanks are a key aspect of healthcare research; they enable access to a wide range of heterogenous samples and data, as well as saving individual researchers time and funds on the collection, storage and/or curation of such resources. However, biobanks are also associated with impacts associated with a depletion of natural resources (energy, water etc.) production of toxic chemicals during manufacturing of laboratory equipment, and effects on biodiversity. We wanted to better understand the biobanking sector in the UK as a first step to assessing the environmental impacts of UK biobanking. METHODS: We explored the sample storage infrastructure and environmental sustainability practices at a number of UK biobanks through a mixed methods quantitative and qualitative approach, including information gathering on an online platform, and eight in-depth interviews. RESULTS: Environmental sustainability was deprioritised behind biobanks' financial sustainability practices. Nevertheless, both often aligned in practice. However, there was a tendency towards underutilisation of stored samples, the avoidance of centralisation, and providing accessibility to biosamples, and this conflicted with valuing sustainability goals. This related to notions of individualised and competitive biobanking culture. Furthermore, the study raised how value attachments to biosamples overshadows needs for both financial and environmental sustainability concerns. CONCLUSIONS: We need to move away from individualised and competitive biobanking cultures towards a realisation that the health of the publics and patients should be first and foremost. We need to ensure the use of biosamples, ahead of their storage ('smart attachments'), align with environmental sustainability goals and participants' donation wishes for biosample use.

HER3-targeted protein chimera forms endosomolytic capsomeres and self-assembles into stealth nucleocapsids for systemic tumor homing of RNA interference in vivo.

RNA interference represents a potent intervention for cancer treatment but requires a robust delivery agent for transporting gene-modulating molecules, such as small interfering RNAs (siRNAs). Although numerous molecular approaches for siRNA delivery are adequate in vitro, delivery to therapeutic targets in vivo is limited by payload integrity, cell targeting, efficient cell uptake, and membrane penetration. We constructed nonviral biomaterials to transport small nucleic acids to cell targets, including tumor cells, on the basis of the self-assembling and cell-penetrating activities of the adenovirus capsid penton base. Our recombinant penton base chimera contains polypeptide domains designed for noncovalent assembly with anionic molecules and tumor homing. Here, structural modeling, molecular dynamics simulations, and functional assays suggest that it forms pentameric units resembling viral capsomeres that assemble into larger capsid-like structures when combined with siRNA cargo. Pentamerization forms a barrel lined with charged residues mediating pH-responsive dissociation and exposing masked domains, providing insight on the endosomolytic mechanism. The therapeutic impact was examined on tumors expressing high levels of HER3/ErbB3 that are resistant to clinical inhibitors. Our findings suggest that our construct may utilize ligand mimicry to avoid host attack and target the siRNA to HER3+ tumors by forming multivalent capsid-like structures.

Confidence in adolescent contraceptive counseling among residents and fellows training at the University of Texas Southwestern in Dallas, Texas.

OBJECTIVES: Evaluate trainees' perceptions of past training and confidence in counseling about five contraceptive methods. STUDY DESIGN: Trainees completed an online survey in 2020. Logistic regressions evaluated the relationship between participant characteristics and confidence. RESULTS: Among 227 respondents (63% response rate), pediatric trainees reported the least confidence in counseling across each contraceptive method. Past training and confidence were associated. CONCLUSIONS: Gaps in training should be addressed to improve confidence in contraceptive counseling among pediatricians in reproductively restricted states. IMPLICATIONS: This study highlights gaps in physician trainee confidence regarding adolescent contraception counseling that should be addressed to improve adolescent sexual and reproductive healthcare.

Discovery of Potent, Selective, and Orally Available IRE1α Inhibitors Demonstrating Comparable PD Modulation to IRE1 Knockdown in a Multiple Myeloma Model.

The lack of selective and safe in vivo IRE1α tool molecules has limited the evaluation of IRE1α as a viable target to treat multiple myeloma. Focus on improving the physicochemical properties of a literature compound by decreasing lipophilicity, molecular weight, and basicity allowed the discovery of a novel series with a favorable in vitro safety profile and good oral exposure. These efforts culminated in the identification of a potent and selective in vivo tool compound, G-5758, that was well tolerated following multiday oral administration of doses up to 500 mg/kg. G-5758 demonstrated comparable pharmacodynamic effects to induced IRE1 knockdown as measured by XBP1s levels in a multiple myeloma model (KMS-11).

Discovery of GuaB inhibitors with efficacy against Acinetobacter baumannii infection.

Guanine nucleotides are required for growth and viability of cells due to their structural role in DNA and RNA, and their regulatory roles in translation, signal transduction, and cell division. The natural antibiotic mycophenolic acid (MPA) targets the rate-limiting step in de novo guanine nucleotide biosynthesis executed by inosine-5´-monophosphate dehydrogenase (IMPDH). MPA is used clinically as an immunosuppressant, but whether in vivo inhibition of bacterial IMPDH (GuaB) is a valid antibacterial strategy is controversial. Here, we describe the discovery of extremely potent small molecule GuaB inhibitors (GuaBi) specific to pathogenic bacteria with a low frequency of on-target spontaneous resistance and bactericidal efficacy in vivo against Acinetobacter baumannii mouse models of infection. The spectrum of GuaBi activity includes multidrug-resistant pathogens that are a critical priority of new antibiotic development. Co-crystal structures of A. baumannii, Staphylococcus aureus, and Escherichia coli GuaB proteins bound to inhibitors show comparable binding modes of GuaBi across species and identifies key binding site residues that are predictive of whole-cell activity across both Gram-positive and Gram-negative clades of Bacteria. The clear in vivo efficacy of these small molecule GuaB inhibitors in a model of A. baumannii infection validates GuaB as an essential antibiotic target. IMPORTANCE: The emergence of multidrug-resistant bacteria worldwide has renewed interest in discovering antibiotics with novel mechanism of action. For the first time ever, we demonstrate that pharmacological inhibition of de novo guanine biosynthesis is bactericidal in a mouse model of Acinetobacter baumannii infection. Structural analyses of novel inhibitors explain differences in biochemical and whole-cell activity across bacterial clades and underscore why this discovery may have broad translational impact on treatment of the most recalcitrant bacterial infections.

Psychometric properties and norms for the Personality Assessment Inventory in egg donors and gestational carriers.

Although psychological evaluations are an integral element of screening for third-party reproduction and the Personality Assessment Inventory (PAI) is commonly used for these evaluations, little is known about the psychometric properties or normative scores on the PAI among egg donors and carriers. We evaluated the PAI among 1,044 egg donors and gestational carriers from various fertility clinics across the United States. PAI scales were generally internally consistent in this population, although range restriction appeared to attenuate reliability on several scales. The PAI profiles of egg donors and carriers had elevated positive impression management and suppressed clinical scale scores relative to the community standardization sample, as would be expected given the contingencies of this assessment context. Scores were similar across egg donors and carriers and were similar whether the carrier or donor was known or not known to the prospective parents. Sample-specific norms are provided for the use of the PAI in this setting.

Long-Acting Reversible Contraception for Adolescents: A Review of Practices to Support Better Communication, Counseling, and Adherence.

Long-acting reversible contraception (LARC) methods, including levonorgestrel and copper intrauterine devices (IUDs) and the subdermal contraceptive implant, are the most effective reversible forms of contraception and thus are an important aspect of adolescent pregnancy prevention. While LARC efficacy, safety, and appropriateness are supported by major medical organizations and usage rates are increasing, overall LARC uptake among United States (US) adolescents remains lower than uptake of short-acting contraceptive methods. A better understanding of the barriers affecting adolescent LARC uptake and reasons for discontinuation could help facilitate effective communication. For example, learning how to improve adolescent-centered communication, shared decision-making, and motivational counseling strategies may be the first step to improving utilization rates. This narrative review includes three sections. First, this review will describe the history, mechanisms of action, and epidemiology of adolescent LARC use in the US and globally. Next, this review will describe key factors influencing adolescent LARC uptake, reasons for discontinuation, and multilevel barriers specific to adolescent LARC use. Finally, this review will characterize communication techniques and LARC counseling strategies for adolescents in the context of a reproductive justice approach set in the health belief model framework. The distinction between moving away from a presumptive counseling approach towards an adolescent-centered, shared decision-making approach to encourage parent-adolescent sexual health communication to lay the foundation of empowering adolescent reproductive autonomy should be the underpinning of all effective reproductive communication strategies.

Discovery of Selective Tertiary Amide Inhibitors of Cyclin-Dependent Kinase 2 (CDK2).

Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle and are frequently altered in cancer cells, thereby leading to uncontrolled proliferation. In this context, CDK2 has emerged as an appealing target for anticancer drug development. Herein, we describe the discovery of a series of selective small molecule inhibitors of CDK2 beginning with historical compounds from our ERK2 program (e.g., compound 6). Structure-based drug design led to the potent and selective tool compound 32, where excellent selectivity against ERK2 and CDK4 was achieved by filling the lipophilic DFG-1 pocket and targeting interactions with CDK2-specific lower hinge binding residues, respectively. Compound 32 demonstrated 112% tumor growth inhibition in mice bearing OVCAR3 tumors with 50 mg/kg bis in die (BID) oral dosing.

Lessons learned from the COVID-19 pandemic about sample access for research in the UK.

OBJECTIVE: Annotated clinical samples taken from patients are a foundation of translational medical research and give mechanistic insight into drug trials. Prior research by the Tissue Directory and Coordination Centre (TDCC) indicated that researchers, particularly those in industry, face many barriers in accessing patient samples. The arrival of the COVID-19 pandemic to the UK produced an immediate and extreme shockwave, which impacted on the ability to undertake all crucial translational research. As a national coordination centre, the TDCC is tasked with improving efficiency in the biobanking sector. Thus, we took responsibility to identify and coordinate UK tissue sample collection organisations (biobanks) able to collect COVID-19-related samples for researchers between March and September 2020. FINDINGS: Almost a third of UK biobanks were closed during the first wave of the UK COVID-19 pandemic. Of the remainder, 43% had limited capabilities while 26% maintained normal activity. Of the nationally prioritised COVID-19 interventional studies, just three of the five that responded to questioning were collecting human samples. Of the 41 requests for COVID-19 samples received by the TDCC, only four could be fulfilled due to a lack of UK coordinated strategy. Meanwhile, in the background there are numerous reports that sample collections in the UK remain largely underutilised. CONCLUSION: The response to a pandemic demands high level co-ordinated research responses to reduce mortality. Our study highlights the lack of efficiency and coordination between human sample collections and clinical trials across the UK. UK sample access is not working for researchers, clinicians or patients. A radical change is required in the strategy for sample collection and distribution to maximise this valuable resource of human-donated samples.

Overcoming Preclinical Safety Obstacles to Discover (S)-N-((1,2,3,5,6,7-Hexahydro-s-indacen-4-yl)carbamoyl)-6-(methylamino)-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine-3-sulfonamide (GDC-2394): A Potent and Selective NLRP3 Inhibitor.

Inappropriate activation of the NLRP3 inflammasome has been implicated in multiple inflammatory and autoimmune diseases. Herein, we aimed to develop novel NLRP3 inhibitors that could minimize the risk of drug-induced liver injury. Lipophilic ligand efficiency was used as a guiding metric to identify a series of 6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazinesulfonylureas. A leading compound from this series was advanced into safety studies in cynomolgus monkeys, and renal toxicity, due to compound precipitation, was observed. To overcome this obstacle, we focused on improving the solubility of our compounds, specifically by introducing basic amine substituents into the scaffold. This led to the identification of GDC-2394, a potent and selective NLRP3 inhibitor, with an in vitro and in vivo safety profile suitable for advancement into human clinical trials.

A mechanistic study of tumor-targeted corrole toxicity.

HerGa is a self-assembled tumor-targeted particle that bears both tumor detection and elimination activities in a single, two-component complex (Agadjanian et al. Proc. Natl. Acad. Sci. U.S.A.2009, 106, 6105-6110). Given its multifunctionality, HerGa (composed of the fluorescent cytotoxic corrole macrocycle, S2Ga, noncovalently bound to the tumor-targeted cell penetration protein, HerPBK10) has the potential for high clinical impact, but its mechanism of cell killing remains to be elucidated, and hence is the focus of the present study. Here we show that HerGa requires HerPBK10-mediated cell entry to induce toxicity. HerGa (but not HerPBK10 or S2Ga alone) induced mitochondrial membrane potential disruption and superoxide elevation, which were both prevented by endosomolytic-deficient mutants, indicating that cytosolic exposure is necessary for corrole-mediated cell death. A novel property discovered here is that corrole fluorescence lifetime acts as a pH indicator, broadcasting the intracellular microenvironmental pH during uptake in live cells. This feature in combination with two-photon imaging shows that HerGa undergoes early endosome escape during uptake, avoiding compartments of pH < 6.5. Cytoskeletal disruption accompanied HerGa-mediated mitochondrial changes whereas oxygen scavenging reduced both events. Paclitaxel treatment indicated that HerGa uptake requires dynamic microtubules. Unexpectedly, low pH is insufficient to induce release of the corrole from HerPBK10. Altogether, these studies identify a mechanistic pathway in which early endosomal escape enables HerGa-induced superoxide generation leading to cytoskeletal and mitochondrial damage, thus triggering downstream cell death.

Secretion of extracellular hsp90alpha via exosomes increases cancer cell motility: a role for plasminogen activation.

BACKGROUND: Metastasis is a multi-step process that is responsible for the majority of deaths in cancer patients. Current treatments are not effective in targeting metastasis. The molecular chaperone hsp90alpha is secreted from invasive cancer cells and activates MMP-2 to enhance invasiveness, required for the first step in metastasis. METHODS: We analyzed the morphology and motility of invasive cancer cells that were treated with exogenous exosomes in the presence or absence of hsp90alpha. We performed mass spectrometry and immunoprecipitation to identify plasminogen as a potential client protein of extracellular hsp90alpha. Plasmin activation assays and migration assays were performed to test if plasminogen is activated by extracellular hsp90alpha and has a role in migration. RESULTS: We found that hsp90alpha is secreted in exosomes in invasive cancer cells and it contributes to their invasive nature. We identified a novel interaction between hsp90alpha and tissue plasminogen activator that together with annexin II, also found in exosomes, activates plasmin. Extracellular hsp90alpha promotes plasmin activation as well as increases plasmin dependent cell motility. CONCLUSIONS: Our data indicate that hsp90alpha is released by invasive cancer cells via exosomes and implicates hsp90alpha in activating plasmin, a second protease that acts in cancer cell invasion.

The Barriers and Motivators to Using Human Tissues for Research: The Views of UK-Based Biomedical Researchers.

Introduction: The use of human-derived samples is vital to numerous areas of biological and medical research. Despite this, researchers often find or anticipate difficulty in sourcing samples. There are ongoing efforts to increase the visibility and accessibility of UK human tissue biobanking, but minimal (if any) research on the reasons behind researchers' choice of sample source has been undertaken. We have analyzed UK researchers' motivations on using their preferred sample sources and their perceived barriers to human sample use. Methods: The study was based on an online survey of academic and industry researchers, followed by focus groups, with participants across the United Kingdom. Both the survey and focus groups probed participants' views on the barriers to finding and using human samples in research. Results: One hundred ninety-eight academic and industry researchers completed the survey on their human sample use, and five focus groups consisting of 21 total participants took place. The top cited reasons for choosing sources included the availability of linked clinical data (40%), the geographical location of the resource (39%), and preexisting collaboration (33%). Focus group participants highlighted their strong preference for local or known sample sources, which were preferred because additional scientific and logistical input could be obtained for their work and they were more confident that the samples would be of good quality. Discussion: We found that there were significant perceptions of governance barriers to sample access. As a consequence, researchers preferred local and known suppliers because of the perception that these could assist with the governance, would be reliable, and able to provide the additional support they required. Equally, data availability was a major contributor to the selection of a new source of samples. These observations are of significant value to those seeking to improve the access to existing sample resources via online discovery tools.

Screening With Reticulocyte Hemoglobin Increased Iron Sufficiency Among NICU Patients.

INTRODUCTION: To increase the rate of iron sufficiency among neonatal intensive care unit (NICU) patients from 16% to >35% within 12 months of implementing standardized assessment of reticulocyte hemoglobin (retHE). METHODS: We implemented a quality improvement (QI) study to improve iron sufficiency in our out-born level III/IV NICU. We screened 2,062 admissions, of which 622 were eligible based on feeding status at discharge. QI interventions included educational efforts and guideline implementation. Our primary outcome measure was the percentage of patients with their discharge retHE measure within the normal range. We also tracked the process measure of the number of retHE tests performed and a balancing measure of the incidence of elevated retHE among patients receiving iron supplementation. Statistical process control (SPC) charts assessed for special cause variation. RESULTS: The percentage of patients with a retHe within the normal range was significantly increased from a mean of 20% to 39% on SPC chart analysis. We measured significantly more retHE values after guideline implementation (11/mo to 24/mo) and found no cases of elevated retHE among patients receiving iron supplementation. CONCLUSIONS: After the implementation of a standardized guideline, a higher rate of iron sufficiency was found in NICU patients at discharge. This work is generalizable to neonatal populations with the potential for a significant impact on clinical practice.

Plasma Free Cortisol in States of Normal and Altered Binding Globulins: Implications for Adrenal Insufficiency Diagnosis.

CONTEXT: Accurate diagnosis of adrenal insufficiency is critical because there are risks associated with overdiagnosis and underdiagnosis. Data using liquid chromatography tandem mass spectrometry (LC/MS/MS) free cortisol (FC) assays in states of high or low cortisol-binding globulin (CBG) levels, including cirrhosis, critical illness, and oral estrogen use, are needed. DESIGN: Cross-sectional. OBJECTIVE: Determine the relationship between CBG and albumin as well as total cortisol (TC) and FC in states of normal and abnormal CBG. Establish the FC level by LC/MS/MS that best predicts TC of <18 µg/dL (497 nmol/L) (standard adrenal insufficiency diagnostic cutoff) in healthy individuals. SUBJECTS: This study included a total of 338 subjects in four groups: healthy control (HC) subjects (n = 243), patients with cirrhosis (n = 38), intensive care unit patients (ICU) (n = 26), and oral contraceptive (OCP) users (n = 31). MAIN OUTCOME MEASURE(S): FC and TC by LC/MS/MS, albumin by spectrophotometry, and CBG by ELISA. RESULTS: TC correlated with FC in the ICU (R = 0.91), HC (R = 0.90), cirrhosis (R = 0.86), and OCP (R = 0.70) groups (all P < 0.0001). In receiver operator curve analysis in the HC group, FC of 0.9 µg/dL (24.8 nmol/L) predicted TC of <18 µg/dL (497 nmol/L; 98% sensitivity, 91% specificity; AUC, 0.98; P < 0.0001). Decreasing the cutoff to 0.7 µg/dL led to a small decrease in sensitivity (92%) with similar specificity (91%). CONCLUSIONS: A cutoff FC of <0.9 µg/dL (25 nmol/L) in this LC/MS/MS assay predicts TC of <18 µg/dL (497 nmol/L) with excellent sensitivity and specificity. This FC cutoff may be helpful in ruling out adrenal insufficiency in patients with binding globulin derangements.

Resistance to receptor-blocking therapies primes tumors as targets for HER3-homing nanobiologics.

Resistance to anti-tumor therapeutics is an important clinical problem. Tumor-targeted therapies currently used in the clinic are derived from antibodies or small molecules that mitigate growth factor activity. These have improved therapeutic efficacy and safety compared to traditional treatment modalities but resistance arises in the majority of clinical cases. Targeting such resistance could improve tumor abatement and patient survival. A growing number of such tumors are characterized by prominent expression of the human epidermal growth factor receptor 3 (HER3) on the cell surface. This study presents a "Trojan-Horse" approach to combating these tumors by using a receptor-targeted biocarrier that exploits the HER3 cell surface protein as a portal to sneak therapeutics into tumor cells by mimicking an essential ligand. The biocarrier used here combines several functions within a single fusion protein for mediating targeted cell penetration and non-covalent self-assembly with therapeutic cargo, forming HER3-homing nanobiologics. Importantly, we demonstrate here that these nanobiologics are therapeutically effective in several scenarios of resistance to clinically approved targeted inhibitors of the human EGF receptor family. We also show that such inhibitors heighten efficacy of our nanobiologics on naïve tumors by augmenting HER3 expression. This approach takes advantage of a current clinical problem (i.e. resistance to growth factor inhibition) and uses it to make tumors more susceptible to HER3 nanobiologic treatment. Moreover, we demonstrate a novel approach in addressing drug resistance by taking inhibitors against which resistance arises and re-introducing these as adjuvants, sensitizing tumors to the HER3 nanobiologics described here.

Lay Consultations in Heart Failure Symptom Evaluation.

PURPOSE: Lay consultations can facilitate or impede healthcare. However, little is known about how lay consultations for symptom evaluation affect treatment decision-making. The purpose of this study was to explore the role of lay consultations in symptom evaluation prior to hospitalization among patients with heart failure. METHODS: Semi-structured interviews were conducted with 60 patients hospitalized for acute decompensated heart failure. Chi-square and Fisher's exact tests, along with logistic regression were used to characterize lay consultations in this sample. RESULTS: A large proportion of patients engaged in lay consultations for symptom evaluation and decision-making before hospitalization. Lay consultants provided attributions and advice and helped make the decision to seek medical care. Men consulted more often with their spouse than women, while women more often consulted with adult children. CONCLUSIONS: Findings have implications for optimizing heart failure self-management interventions, improving outcomes, and reducing hospital readmissions.

Basal Protein Expression Is Associated With Worse Outcome and Trastuzamab Resistance in HER2+ Invasive Breast Cancer.

BACKGROUND: We investigated the effect of basal protein expression on trastuzamab response in patients with HER2-positive (HER2(+)) breast cancer who received trastuzamab (T) and in HER2(+) breast cancer cell lines. PATIENTS AND METHODS: Expression of cytokeratin (CK) 5/6, CK14, and epidermal growth factor receptor (EGFR) was evaluated after immunohistochemical staining in paraffin-embedded tissue of 97 patients with stage I to III HER2(+) breast cancer treated with chemotherapy/T. Groups with and without basal protein expression were compared with respect to clinicopathologic parameters and survival. We treated 4 cell lines (2 basal-HER2 [HCC1569, HCC1954] and 2 nonbasal HER2 [BT474, SKBR3]) each with vehicle, T 20 µg/mL, paclitaxel 0.01 µM (P), and T with P (T + P). Cell viability was assessed and HER2 pathway suppression was compared between groups using immunoblot analysis. Mammosphere formation was used to assess breast cancer stem cell properties. RESULTS: EGFR expression was significantly associated with cancer-specific survival (CSS) (P = .05). CK5/6 expression strongly correlated with overall and disease-free survival, and CSS (P = .03, P = .04, and P = .03, respectively). Statistical significance was maintained for EGFR and CK5/6 after adjustment for covariates. CK14 was not associated with survival. All cell lines expressed similar levels of HER2. T and P alone inhibited proliferation of nonbasal cell lines; T + P had an additive cytotoxic effect. Basal cells were resistant to T, P inhibited proliferation, but T + P had no additive cytotoxic effect on cell growth in basal cells. Immunoblot analysis showed a significant decrease in phosphorylated Akt levels after treatment with T or T + P in nonbasal cells but not in basal cells. Akt blockade suppressed growth of basal and nonbasal HER2(+) cells. Furthermore, basal HER2 cell lines had increased mammosphere formation, which suggests increased stem cell properties compared with nonbasal HER2 cell lines. CONCLUSION: CK5/6 and EGFR expression are predictive of worse prognosis in HER2(+) breast cancer patients treated with T. Basal HER2 breast cancer cell lines are resistant to trastuzamab, which is mediated through the Akt pathway; AKT inhibition abrogates this resistance. Basal HER2 cell lines also have increased stem cell properties, which might play a role in the resistance pathway.

A corrole nanobiologic elicits tissue-activated MRI contrast enhancement and tumor-targeted toxicity.

Water-soluble corroles with inherent fluorescence can form stable self-assemblies with tumor-targeted cell penetration proteins, and have been explored as agents for optical imaging and photosensitization of tumors in pre-clinical studies. However, the limited tissue-depth of excitation wavelengths limits their clinical applicability. To examine their utility in more clinically-relevant imaging and therapeutic modalities, here we have explored the use of corroles as contrast enhancing agents for magnetic resonance imaging (MRI), and evaluated their potential for tumor-selective delivery when encapsulated by a tumor-targeted polypeptide. We have found that a manganese-metallated corrole exhibits significant T1 relaxation shortening and MRI contrast enhancement that is blocked by particle formation in solution but yields considerable MRI contrast after tissue uptake. Cell entry but not low pH enables this. Additionally, the corrole elicited tumor-toxicity through the loss of mitochondrial membrane potential and cytoskeletal breakdown when delivered by the targeted polypeptide. The protein-corrole particle (which we call HerMn) exhibited improved therapeutic efficacy compared to current targeted therapies used in the clinic. Taken together with its tumor-preferential biodistribution, our findings indicate that HerMn can facilitate tumor-targeted toxicity after systemic delivery and tumor-selective MR imaging activatable by internalization.