Regulated induced proximity targeting chimeras-RIPTACs-A heterobifunctional small molecule strategy for cancer selective therapies.

We describe a protein proximity inducing therapeutic modality called Regulated Induced Proximity Targeting Chimeras or RIPTACs: heterobifunctional small molecules that elicit a stable ternary complex between a target protein (TP) selectively expressed in tumor cells and a pan-expressed protein essential for cell survival. The resulting co-operative protein-protein interaction (PPI) abrogates the function of the essential protein, thus leading to death selectively in cells expressing the TP. This approach leverages differentially expressed intracellular proteins as novel cancer targets, with the advantage of not requiring the target to be a disease driver. In this chemical biology study, we design RIPTACs that incorporate a ligand against a model TP connected via a linker to effector ligands such as JQ1 (BRD4) or BI2536 (PLK1) or CDK inhibitors such as TMX3013 or dinaciclib. RIPTACs accumulate selectively in cells expressing the HaloTag-FKBP target, form co-operative intracellular ternary complexes, and induce an anti-proliferative response in target-expressing cells.

Acute splenic pathology on CT in patients with babesiosis.

PURPOSE: To better understand the occurrence of splenic disease as a potential manifestation of babesiosis by retrospectively estimating the frequency of acute splenic injury on abdominal and pelvic CT in a cohort of patients with active babesia infection. MATERIALS AND METHODS: In a search of our single institution, suburban teaching community hospital database, 57 patients were found to have positive babesia infection between the years 2021-2023. 29 of these patients underwent abdominal and pelvic CT (22 with and 7 without intravenous contrast), and 3 underwent abdominal ultrasound without any CT. The imaging was reviewed for the presence or absence of splenic abnormalities, and for follow-up imaging. Parasitemia levels at the time of imaging were also reviewed; parasitemia levels < 4% are associated with mild to moderate disease, whereas parasitemia levels > 4% are associated with severe disease. RESULTS: 21/32 (66%) patients who underwent any type of abdominal imaging (ultrasound, MRI, and CT) had splenomegaly. Of the 22 patients who had IV contrast-enhanced CT scans, 6 were found to have splenic infarction (27%). One of these 22 patients had multiple rounded non-peripheral hypoenhancing foci on both CT and MRI which did not meet criteria for infarction, in association with splenomegaly, and which resolved after treatment. 0/6 patients in the splenic infarction group had parasitemia levels greater than 4%, while 4 of the 16 patients (4/16) without infarction had parasitemia levels of greater than 4%. CONCLUSION: Our study showed that splenic disease in patients with babesiosis mostly took the form of splenomegaly, and in a substantial minority of patients as splenic infarction. There were no cases of splenic rupture and perisplenic hematoma in our case series, likely reflecting a limitation of the relatively small study size. Concordant with prior studies, we found no identifiable association between parasitemia levels and the presence of splenic infarction.

The impact of disability on recruitment to higher surgical specialty training: A retrospective cohort study.

BACKGROUND: UK examining bodies are required to eliminate discrimination against people with protected characteristics. To achieve this in surgery, differential attainment (DA) in assessments used as gatekeepers to career progression must be ruled out. This study investigated the impact of disability status on the likelihood of success at national selection for Higher Surgical Training (HST). METHODS: A retrospective cohort study of all UK graduates in the UKMED database (https://www.ukmed.ac.uk) who underwent selection for HST (ST3) from 2012 to 2019 (n = 2875). Univariate analysis identified differences in success rates at first-application. Logistic regression models identified whether disability was a predictor of success after adjusting for sociodemographic factors and prior MRCS performance. RESULTS: There was no significant difference in success rates between candidates with and without disabilities (all p > 0.05) for any surgical specialty. Disability status was not a statistically significant predictor of success. Female candidates were 25 % more likely to be successful (OR 1.25 [95%CI 1.05 to 1.49]) and Non-White candidates were 20 % less likely to be successful (OR 0.80 [95%CI 0.68 to 0.96]). Candidates who passed MRCS Part A and Part B at the first attempt were 49 % (OR 1.49 [95%CI 1.25 to 1.77]) and 90 % (OR 1.90 [95%CI 1.58 to 2.28]) more likely to be successful. CONCLUSION: No significant difference was found in the likelihood of being successful at HST selection for any surgical specialty between applicants with and without disabilities, regardless of type of disability. DA was identified between other sociodemographic groups which requires further exploration.

EGFR targeting PhosTACs as a dual inhibitory approach reveals differential downstream signaling.

We recently developed a heterobifunctional approach [phosphorylation targeting chimeras (PhosTACs)] to achieve the targeted protein dephosphorylation (TPDephos). Here, we envisioned combining the inhibitory effects of receptor tyrosine kinase inhibitors (RTKIs) and the active dephosphorylation by phosphatases to achieve dual inhibition of kinases. We report an example of tyrosine phosphatase-based TPDephos and the effective epidermal growth factor receptor (EGFR) tyrosine dephosphorylation. We also used phosphoproteomic approaches to study the signaling transductions affected by PhosTAC-related molecules at the proteome-wide level. This work demonstrated the differential signaling pathways inhibited by PhosTAC compared with the TKI, gefitinib. Moreover, a covalent PhosTAC selective for mutated EGFR was developed and showed its inhibitory potential for dysregulated EGFR. Last, EGFR PhosTACs, consistent with EGFR dephosphorylation profiles, induced apoptosis and inhibited cancer cell viability during prolonged PhosTAC treatment. PhosTACs showcased their potential of modulating RTKs activity, expanding the scope of bifunctional molecule utility.

Development of a Small Molecule Downmodulator for the Transcription Factor Brachyury.

Brachyury is an oncogenic transcription factor whose overexpression drives chordoma growth. The downmodulation of brachyury in chordoma cells has demonstrated therapeutic potential, however, as a transcription factor it is classically deemed "undruggable". Given that direct pharmacological intervention against brachyury has proven difficult, attempts at intervention have instead targeted upstream kinases. Recently, afatinib, an FDA-approved kinase inhibitor, has been shown to modulate brachyury levels in multiple chordoma cell lines. Herein, we use afatinib as a lead to undertake a structure-based drug design approach, aided by mass-spectrometry and X-ray crystallography, to develop DHC-156, a small molecule that more selectively binds brachyury and downmodulates it as potently as afatinib. We eliminated kinase-inhibition from this novel scaffold while demonstrating that DHC-156 induces the post-translational downmodulation of brachyury that results in an irreversible impairment of chordoma tumor cell growth. In doing so, we demonstrate the feasibility of direct brachyury modulation, which may further be developed into more potent tool compounds and therapies.

Picture Perfect: The Status of Image Quality in Prostate MRI.

Magnetic resonance imaging is the gold standard imaging modality for the diagnosis of prostate cancer (PCa). Image quality is a fundamental prerequisite for the ability to detect clinically significant disease. In this critical review, we separate the issue of image quality into quality improvement and quality assessment. Beginning with the evolution of technical recommendations for scan acquisition, we investigate the role of patient preparation, scanner factors, and more advanced sequences, including those featuring Artificial Intelligence (AI), in determining image quality. As means of quality appraisal, the published literature on scoring systems (including the Prostate Imaging Quality score), is evaluated. Finally, the application of AI and teaching courses as ways to facilitate quality assessment are discussed, encouraging the implementation of future image quality initiatives along the PCa diagnostic and monitoring pathway. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Establishing the predictive validity of the intercollegiate membership of the Royal Colleges of surgeons written examination: MRCS Part A.

Successful completion of the Intercollegiate Membership of the Royal Colleges of Surgeons (MRCS) examination is mandatory for surgical trainees entering higher specialist training in the United Kingdom. Despite its international reputation, and the value placed on the examination in surgical training, there has been little evidence of its predictive validity until recently. In this review, we present a summary of findings of four recent Intercollegiate studies assessing the predictive validity of the MRCS Part A (written) examination. Data from all four studies showed statistically significant positive correlations between the MRCS Part A and other written examinations taken by surgical trainees over the course of their education. The studies summarised in this review provide compelling evidence for the predictive validity of this gatekeeping examination. This review will be of interest to trainees, training institutions and the Royal Colleges given the value placed on the examination by surgical training programmes.

Establishing the predictive validity of the intercollegiate membership of the Royal Colleges of surgeons written examination: MRCS part B.

The Intercollegiate Membership of the Royal Colleges of Surgeons (MRCS) is a high-stakes postgraduate examination taken by thousands of surgical trainees worldwide every year. The MRCS is a challenging assessment, highly regarded by surgical training programmes and valued as a gatekeeper to the surgical profession. The examination is taken at considerable personal, social and financial cost to surgical trainees, and failure has significant implications for career progression. Given the value placed on MRCS, it must be a reliable and valid assessment of the knowledge and skills of early-career surgeons. Our first article 'Establishing the Predictive Validity of the Intercollegiate Membership of the Royal Colleges of Surgeons Written Examination: MRCS Part A' discussed the principles of assessment reliability and validity and outlined the mounting evidence supporting the predictive validity of the MRCS Part A (the multiple-choice questionnaire component of the examination). This, the second article in the series discusses six recently published studies investigating the predictive validity of the MRCS Part B (the clinical component of the examination). All national longitudinal cohort studies reviewed have demonstrated significant correlations between MRCS Part B and other assessments taken during the UK surgical training pathway, supporting the predictive validity of MRCS Part B. This review will be of interest to trainees, trainers and Royal Colleges given the value placed on the examination by surgical training programmes.

A semi-automated software program to assess the impact of second reads in prostate MRI for equivocal lesions: results from a UK tertiary referral centre.

PURPOSE: To investigate the utility of a prostate magnetic resonance imaging (MRI) second read using a semi-automated software program in the one-stop clinic, where patients undergo multiparametric MRI, review and biopsy planning in one visit. We looked at concordance between readers for patients with equivocal scans and the possibility for biopsy deferral in this group. METHODS: We present data from 664 consecutive patients. Scans were reported by seven different expert genitourinary radiologists using dedicated software (MIM®) and a Likert scale. All scans were rescored by another expert genitourinary radiologist using a customised workflow for second reads that includes annotated biopsy contours for accurate visual targeting. The number of scans in which a biopsy could have been deferred using biopsy results and prostate specific antigen density was assessed. Gleason score ≥ 3 + 4 was considered clinically significant disease. Concordance between first and second reads for equivocal scans (Likert 3) was evaluated. RESULTS: A total of 209/664 (31%) patients scored Likert 3 on first read, 128 of which (61%) were concordant after second read. 103/209 (49%) of patients with Likert 3 scans were biopsied, with clinically significant disease in 31 (30%) cases. Considering Likert 3 scans that were both downgraded and biopsied using the workflow-generated biopsy contours, 25/103 (24%) biopsies could have been deferred. CONCLUSIONS: Implementing a semi-automated workflow for accurate lesion contouring and targeting biopsies is helpful during the one-stop clinic. We observed a reduction of indeterminate scans after second reading and almost a quarter of biopsies could have been deferred, reducing the potential biopsy-related side effects.

Targeted Dephosphorylation of Tau by Phosphorylation Targeting Chimeras (PhosTACs) as a Therapeutic Modality.

Microtubule-associated protein tau is essential for microtubule assembly and stabilization. Hyperphosphorylation of the microtubule-associated protein tau plays an important pathological role in the development of Alzheimer's disease and other tauopathies. In vivo studies using kinase inhibitors suggest that reducing tau phosphorylation levels has therapeutic potential; however, such approaches showed limited benefits. We sought to further develop our phosphorylation targeting chimera (PhosTAC) technology to specifically induce tau dephosphorylation. Herein, we use small molecule-based PhosTACs to recruit tau to PP2A, a native tau phosphatase. PhosTACs induced the formation of a stable ternary complex, leading to rapid, efficient, and sustained tau dephosphorylation, which also correlated with the enhanced downregulation of tau protein. Mass spectrometry data validated that PhosTACs downregulated multiple phosphorylation sites of tau. We believe that PhosTAC possesses several advantages over current strategies to modulate tau phosphorylation and represents a new avenue for disease-modifying therapies for tauopathies.

Examining the diversity of MRCS examiners.

BACKGROUND: MRCS examiners are the face of the Royal College of Surgeons for early-career surgeons and should therefore represent the workforce they are examining as not to marginalise or negatively impact on the assessment experience of candidates from minoritised groups. This study aimed to explore the diversity of MRCS examiners and whether they represent the demographics of the MRCS candidates. METHODS: A retrospective observational study including all active examiners and examination candidates who attempted MRCS Part A or Part B between January 2020 and July 2021. Self-declared demographic data collected by the Intercollegiate Committee for Basic Surgical Examinations (ICBSE) included gender, sexual orientation, disability status and ethnicity. Following data anonymisation, total group response frequencies were made available to the research team for statistical analysis. RESULTS: Chi-squared analyses showed statistically significant differences in the representation of gender, disability and ethnicity between candidates and examiners (all p < 0.001). Men (83.9% (n = 1121) vs 70.9% (n = 6017) respectively), individuals without disability (98.7% (n = 917) vs 96.1% (n = 6847)) and individuals of White ethnicity (36.6% (n = 346) vs 20.4% (n = 1223)) were significantly overrepresented in the examiners compared to the examination candidates. There was no statistically significant difference in sexual orientation between examiners and candidates (p = 0.712). CONCLUSIONS: Broadly speaking, the socio-demographic profile of MRCS examiners reflects that seen in senior and leadership positions in surgery in the UK - that is, predominantly male and White - but not that seen in early-career surgeons. Positive action is now required in examiner recruitment by the Royal Colleges to ensure that the cohort of MRCS examiners reflects the modern surgical workforce.

Regulated Induced Proximity Targeting Chimeras (RIPTACs): a Novel Heterobifunctional Small Molecule Therapeutic Strategy for Killing Cancer Cells Selectively.

While specific cell signaling pathway inhibitors have yielded great success in oncology, directly triggering cancer cell death is one of the great drug discovery challenges facing biomedical research in the era of precision oncology. Attempts to eradicate cancer cells expressing unique target proteins, such as antibody-drug conjugates (ADCs), T-cell engaging therapies, and radiopharmaceuticals have been successful in the clinic, but they are limited by the number of targets given the inability to target intracellular proteins. More recently, heterobifunctional small molecules such as Proteolysis Targeting Chimera (PROTACs) have paved the way for protein proximity inducing therapeutic modalities. Here, we describe a proof-of-concept study using novel heterobifunctional small molecules called Regulated Induced Proximity Targeting Chimeras or RIPTACs, which elicit a stable ternary complex between a target protein selectively expressed in cancer tissue and a pan-expressed protein essential for cell survival. The resulting cooperative protein:protein interaction (PPI) abrogates the function of the essential protein, thus leading to cell death selectively in cells expressing the target protein. This approach not only opens new target space by leveraging differentially expressed intracellular proteins but also has the advantage of not requiring the target to be a driver of disease. Thus, RIPTACs can address non-target mechanisms of resistance given that cell killing is driven by inactivation of the essential protein. Using the HaloTag7-FKBP model system as a target protein, we describe RIPTACs that incorporate a covalent or non-covalent target ligand connected via a linker to effector ligands such as JQ1 (BRD4), BI2536 (PLK1), or multi-CDK inhibitors such as TMX3013 or dinaciclib. We show that these RIPTACs exhibit positive co-operativity, accumulate selectively in cells expressing HaloTag7-FKBP, form stable target:RIPTAC:effector trimers in cells, and induce an anti-proliferative response in target-expressing cells. We propose that RIPTACs are a novel heterobifunctional therapeutic modality to treat cancers that are known to selectively express a specific intracellular protein.

The Anglo-Saxon migration and the formation of the early English gene pool.

The history of the British Isles and Ireland is characterized by multiple periods of major cultural change, including the influential transformation after the end of Roman rule, which precipitated shifts in language, settlement patterns and material culture1. The extent to which migration from continental Europe mediated these transitions is a matter of long-standing debate2-4. Here we study genome-wide ancient DNA from 460 medieval northwestern Europeans-including 278 individuals from England-alongside archaeological data, to infer contemporary population dynamics. We identify a substantial increase of continental northern European ancestry in early medieval England, which is closely related to the early medieval and present-day inhabitants of Germany and Denmark, implying large-scale substantial migration across the North Sea into Britain during the Early Middle Ages. As a result, the individuals who we analysed from eastern England derived up to 76% of their ancestry from the continental North Sea zone, albeit with substantial regional variation and heterogeneity within sites. We show that women with immigrant ancestry were more often furnished with grave goods than women with local ancestry, whereas men with weapons were as likely not to be of immigrant ancestry. A comparison with present-day Britain indicates that subsequent demographic events reduced the fraction of continental northern European ancestry while introducing further ancestry components into the English gene pool, including substantial southwestern European ancestry most closely related to that seen in Iron Age France5,6.

Cost-Utility Analysis of Major System Change in Specialist Cancer Surgery in London, England, Using Linked Patient-Level Electronic Health Records and Difference-in-Differences Analysis.

BACKGROUND: Studies have shown that centralising surgical treatment for some cancers can improve patient outcomes, but there is limited evidence of the impact on costs or health-related quality of life. OBJECTIVES: We report the results of a cost-utility analysis of the RESPECT-21 study using difference-in-differences, which investigated the reconfiguration of specialist surgery services for four cancers in an area of London, compared to the Rest of England (ROE). METHODS: Electronic health records data were obtained from the National Cancer Registration and Analysis Service for patients diagnosed with one of the four cancers of interest between 2012 and 2017. The analysis for each tumour type used a short-term decision tree followed by a 10-year Markov model with 6-monthly cycles. Costs were calculated by applying National Health Service (NHS) Reference Costs to patient-level hospital resource use and supplemented with published data. Cancer-specific preference-based health-related quality-of-life values were obtained from the literature to calculate quality-adjusted life-years (QALYs). Total costs and QALYs were calculated before and after the reconfiguration, in the London Cancer (LC) area and in ROE, and probabilistic sensitivity analysis was performed to illustrate the uncertainty in the results. RESULTS: At a threshold of £30,000/QALY gained, LC reconfiguration of prostate cancer surgery services had a 79% probability of having been cost-effective compared to non-reconfigured services using difference-in-differences. The oesophago-gastric, bladder and renal reconfigurations had probabilities of 62%, 49% and 12%, respectively, of being cost-effective at the same threshold. Costs and QALYs per surgical patient increased over time for all cancers across both regions to varying degrees. Bladder cancer surgery had the smallest patient numbers and changes in costs, and QALYs were not significant. The largest improvement in outcomes was in renal cancer surgery in ROE, making the relative renal improvements in LC appear modest, and the probability of the LC reconfiguration having been cost-effective low. CONCLUSIONS: Prostate cancer reconfigurations had the highest probability of being cost-effective. It is not clear, however, whether the prostate results can be considered in isolation, given the reconfigurations occurred simultaneously with other system changes, and healthcare delivery in the NHS is highly networked and collaborative. Routine collection of quality-of-life measures such as the EQ-5D-5L would have improved the analysis.

Loss associated with subtractive health service change: The case of specialist cancer centralization in England.

OBJECTIVE: Major system change can be stressful for staff involved and can result in 'subtractive change' - that is, when a part of the work environment is removed or ceases to exist. Little is known about the response to loss of activity resulting from such changes. Our aim was to understand perceptions of loss in response to centralization of cancer services in England, where 12 sites offering specialist surgery were reduced to four, and to understand the impact of leadership and management on enabling or hampering coping strategies associated with that loss. METHODS: We analysed 115 interviews with clinical, nursing and managerial staff from oesophago-gastric, prostate/bladder and renal cancer services in London and West Essex. In addition, we used 134 hours of observational data and analysis from over 100 documents to contextualize and to interpret the interview data. We performed a thematic analysis drawing on stress-coping theory and organizational change. RESULTS: Staff perceived that, during centralization, sites were devalued as the sites lost surgical activity, skills and experienced teams. Staff members believed that there were long-term implications for this loss, such as in retaining high-calibre staff, attracting trainees and maintaining autonomy. Emotional repercussions for staff included perceived loss of status and motivation. To mitigate these losses, leaders in the centralization process put in place some instrumental measures, such as joint contracting, surgical skill development opportunities and trainee rotation. However, these measures were undermined by patchy implementation and negative impacts on some individuals (e.g. increased workload or travel time). Relatively little emotional support was perceived to be offered. Leaders sometimes characterized adverse emotional reactions to the centralization as resistance, to be overcome through persuasion and appeals to the success of the new system. CONCLUSIONS: Large-scale reorganizations are likely to provoke a high degree of emotion and perceptions of loss. Resources to foster coping and resilience should be made available to all organizations within the system as they go through major change.

Hijacking Methyl Reader Proteins for Nuclear-Specific Protein Degradation.

Targeted protein degradation (TPD) by PROTACs is a promising strategy to control disease-causing protein levels within the cell. While TPD is emerging as an innovative drug discovery paradigm, there are currently only a limited number of E3 ligase:ligand pairs that are employed to induce protein degradation. Herein, we report a novel approach to induce protein degradation by hijacking a methyl reader:E3 ligase complex. L3MBTL3 is a methyl-lysine reader protein that binds to the Cul4DCAF5 E3 ligase complex and targets methylated proteins for proteasomal degradation. By co-opting this natural mechanism, we report the design and biological evaluation of L3MBTL3-recruiting PROTACs and demonstrate nuclear-specific degradation of FKBP12 and BRD2. We envision this as a generalizable approach to utilize other reader protein-associated E3 ligase complexes in PROTAC design to expand the E3 ligase toolbox and explore the full potential of TPD.

Inter-organisational collaboration enabling care delivery in a specialist cancer surgery provider network: A qualitative study.

OBJECTIVE: To explore the processes, challenges and strategies used to govern and maintain inter-organisational collaboration between professionals in a provider network in London, United Kingdom, which implemented major system change focused on the centralisation of specialist cancer surgery. METHODS: We used a qualitative design involving interviews with stakeholders (n = 117), non-participant observations (n = 163) and documentary analysis (n = 100). We drew on an existing model of collaboration in healthcare organisations and expanded this framework by applying it to the analysis of collaboration in the context of major system change. RESULTS: Network provider organisations established shared goals, maintained central figures who could create and sustain collaboration, and promoted distributed forms of leadership. Still, organisations continued to encounter barriers or challenges in relation to developing opportunities for mutual acquaintanceship across all professional groups; the active sharing of knowledge, expertise and good practice across the network; the fostering of trust; and creation of information exchange infrastructures fit for collaborative purposes. CONCLUSION: Collaborative relationships changed over time, becoming stronger post-implementation in some areas, but continued to be negotiated where resistance to the centralisation remained. Future research should explore the sustainability of these relationships and further unpack how hierarchies and power relationships shape inter-organisational collaboration.

How to Cost the Implementation of Major System Change for Economic Evaluations: Case Study Using Reconfigurations of Specialist Cancer Surgery in Part of London, England.

BACKGROUND: Studies have been published regarding the impact of major system change (MSC) on care quality and outcomes, but few evaluate implementation costs or include them in cost-effectiveness analysis (CEA). This is despite large potential costs of MSC: change planning, purchasing or repurposing assets, and staff time. Implementation costs can influence implementation decisions. We describe our framework and principles for costing MSC implementation and illustrate them using a case study. METHODS: We outlined MSC implementation stages and identified components, using a framework conceived during our work on MSC in stroke services. We present a case study of MSC of specialist surgery services for prostate, bladder, renal and oesophagogastric cancers, focusing on North Central and North East London and West Essex. Health economists collaborated with qualitative researchers, clinicians and managers, identifying key reconfiguration stages and expenditures. Data sources (n = approximately 100) included meeting minutes, interviews, and business cases. National Health Service (NHS) finance and service managers and clinicians were consulted. Using bottom-up costing, items were identified, and unit costs based on salaries, asset costs and consultancy fees assigned. Itemised costs were adjusted and summed. RESULTS: Cost components included options appraisal, bidding process, external review; stakeholder engagement events; planning/monitoring boards/meetings; and making the change: new assets, facilities, posts. Other considerations included hospital tariff changes; costs to patients; patient population; and lifetime of changes. Using the framework facilitated data identification and collection. The total adjusted implementation cost was estimated at £7.2 million, broken down as replacing robots (£4.0 million), consultancy fees (£1.9 million), staff time costs (£1.1 million) and other costs (£0.2 million). CONCLUSIONS: These principles can be used by funders, service providers and commissioners planning MSC and researchers evaluating MSC. Health economists should be involved early, alongside qualitative and health-service colleagues, as retrospective capture risks information loss. These analyses are challenging; many cost factors are difficult to identify, access and measure, and assumptions regarding lifetime of the changes are important. Including implementation costs in CEA might make MSC appear less cost effective, influencing future decisions. Future work will incorporate this implementation cost into the full CEAs of the London Cancer MSC. TRIAL REGISTRATION: Not applicable.