PI3Kγ in B cells promotes antibody responses and generation of antibody-secreting cells.

The differentiation of naive and memory B cells into antibody-secreting cells (ASCs) is a key feature of adaptive immunity. The requirement for phosphoinositide 3-kinase-delta (PI3Kδ) to support B cell biology has been investigated intensively; however, specific functions of the related phosphoinositide 3-kinase-gamma (PI3Kγ) complex in B lineage cells have not. In the present study, we report that PI3Kγ promotes robust antibody responses induced by T cell-dependent antigens. The inborn error of immunity caused by human deficiency in PI3Kγ results in broad humoral defects, prompting our investigation of roles for this kinase in antibody responses. Using mouse immunization models, we found that PI3Kγ functions cell intrinsically within activated B cells in a kinase activity-dependent manner to transduce signals required for the transcriptional program supporting differentiation of ASCs. Furthermore, ASC fate choice coincides with upregulation of PIK3CG expression and is impaired in the context of PI3Kγ disruption in naive B cells on in vitro CD40-/cytokine-driven activation, in memory B cells on toll-like receptor activation, or in human tonsillar organoids. Taken together, our study uncovers a fundamental role for PI3Kγ in supporting humoral immunity by integrating signals instructing commitment to the ASC fate.

Patient-derived mini-colons enable long-term modeling of tumor-microenvironment complexity.

Existing organoid models fall short of fully capturing the complexity of cancer because they lack sufficient multicellular diversity, tissue-level organization, biological durability and experimental flexibility. Thus, many multifactorial cancer processes, especially those involving the tumor microenvironment, are difficult to study ex vivo. To overcome these limitations, we herein implemented tissue-engineering and microfabrication technologies to develop topobiologically complex, patient-specific cancer avatars. Focusing on colorectal cancer, we generated miniature tissues consisting of long-lived gut-shaped human colon epithelia ('mini-colons') that stably integrate cancer cells and their native tumor microenvironment in a format optimized for real-time, high-resolution evaluation of cellular dynamics. We demonstrate the potential of this system through several applications: a comprehensive evaluation of drug effectivity, toxicity and resistance in anticancer therapies; the discovery of a mechanism triggered by cancer-associated fibroblasts that drives cancer invasion; and the identification of immunomodulatory interactions among different components of the tumor microenvironment. Similar approaches should be feasible for diverse tumor types.

Bioengineered human colon organoids with in vivo-like cellular complexity and function.

Organoids and organs-on-a-chip have emerged as powerful tools for modeling human gut physiology and disease in vitro. Although physiologically relevant, these systems often lack the environmental milieu, spatial organization, cell type diversity, and maturity necessary for mimicking human intestinal mucosa. To instead generate models closely resembling in vivo tissue, we herein integrated organoid and organ-on-a-chip technology to develop an advanced human organoid model, called "mini-colons." By employing an asymmetric stimulation with growth factors, we greatly enhanced tissue longevity and replicated in vivo-like diversity and patterning of proliferative and differentiated cell types. Mini-colons contain abundant mucus-producing goblet cells and, signifying mini-colon maturation, single-cell RNA sequencing reveals emerging mature and functional colonocytes. This methodology is expanded to generate microtissues from the small intestine and incorporate additional microenvironmental components. Finally, our bioengineered organoids provide a precise platform to systematically study human gut physiology and pathology, and a reliable preclinical model for drug safety assessment.

Nanoplasmonic Single-Tumoroid Microarray for Real-Time Secretion Analysis.

Organoid tumor models have emerged as a powerful tool in the fields of biology and medicine as such 3D structures grown from tumor cells recapitulate better tumor characteristics, making these tumoroids unique for personalized cancer research. Assessment of their functional behavior, particularly protein secretion, is of significant importance to provide comprehensive insights. Here, a label-free spectroscopic imaging platform is presented with advanced integrated optofluidic nanoplasmonic biosensor that enables real-time secretion analysis from single tumoroids. A novel two-layer microwell design isolates tumoroids, preventing signal interference, and the microarray configuration allows concurrent analysis of multiple tumoroids. The dual imaging capability combining time-lapse plasmonic spectroscopy and bright-field microscopy facilitates simultaneous observation of secretion dynamics, motility, and morphology. The integrated biosensor is demonstrated with colorectal tumoroids derived from both cell lines and patient samples to investigate their vascular endothelial growth factor A (VEGF-A) secretion, growth, and movement under various conditions, including normoxia, hypoxia, and drug treatment. This platform, by offering a label-free approach with nanophotonics to monitor tumoroids, can pave the way for new applications in fundamental biological studies, drug screening, and the development of therapies.

Hue selectivity from recurrent circuitry in Drosophila.

In the perception of color, wavelengths of light reflected off objects are transformed into the derived quantities of brightness, saturation and hue. Neurons responding selectively to hue have been reported in primate cortex, but it is unknown how their narrow tuning in color space is produced by upstream circuit mechanisms. We report the discovery of neurons in the Drosophila optic lobe with hue-selective properties, which enables circuit-level analysis of color processing. From our analysis of an electron microscopy volume of a whole Drosophila brain, we construct a connectomics-constrained circuit model that accounts for this hue selectivity. Our model predicts that recurrent connections in the circuit are critical for generating hue selectivity. Experiments using genetic manipulations to perturb recurrence in adult flies confirm this prediction. Our findings reveal a circuit basis for hue selectivity in color vision.

Associations between brain morphology, inflammatory markers and symptoms of fatigue, depression or anxiety in active and remitted Crohn's disease.

BACKGROUND: Fatigue and psychosocial impairments are highly prevalent in IBD, especially during active disease. Disturbed brain-gut-interactions may contribute to these symptoms. This study examined associations between brain structure, faecal calprotectin and symptoms of fatigue, depression and anxiety in persons with Crohn's Disease (CD) in different disease states. METHODS: In this prospective observational study, n=109 participants (n=67 persons with CD, n=42 healthy controls) underwent cranial magnetic resonance imaging, provided stool samples for analysis of faecal calprotectin and completed questionnaires to assess symptoms of fatigue, depression and anxiety. We analysed differences in grey matter volume (GMV) between patients and controls and associations between regional GMV alterations, neuropsychiatric symptoms and faecal calprotectin. RESULTS: Symptoms of fatigue, depression and anxiety were increased in patients with CD compared to controls, with highest scores in active CD. Patients exhibited regionally reduced GMV in cortical and subcortical sensorimotor regions, occipitotemporal and medial frontal areas. Regional GMV differences showed a significant negative association with fatigue, but not with depression or anxiety. Subgroup analyses revealed symptom-GMV-associations for fatigue in remitted, but not in active CD, while fatigue was positively associated with faecal calprotectin in active, but not remitted disease. CONCLUSION: Our findings support disturbed brain-gut-interactions in CD which may be particularly relevant for fatigue during remitted disease. Reduced GMV in the precentral gyrus and other sensorimotor areas could reflect key contributions to fatigue pathophysiology in CD. A sensorimotor model of fatigue in CD could also pave the way for novel treatment approaches.

A systematic review of diagnostic and interventional techniques in non-occlusive hepatic artery hypoperfusion syndrome.

OBJECTIVE: This systematic review aims to elucidate the diagnostic capabilities of imaging techniques in identifying Non-Occlusive Hepatic Artery Hypoperfusion Syndrome (NOHAH) and to evaluate the efficacy and outcomes of splenic artery embolization (SAE), including the choice and placement of embolic agents. MATERIALS AND METHODS: A comprehensive literature search was conducted using PubMed, CINAHL, and Scopus databases, adhering to PRISMA guidelines. Fifteen studies encompassing 240 patients treated with embolization (using coils or Amplatzer Vascular Plugs (AVP)) were analyzed. Key metrics assessed included patient demographics, embolization techniques, embolic agents, technical success, radiologic findings pre- and post-embolization, and complication rates. RESULTS: Among the 240 patients studied, 177 (73.8%) were reported by gender, with a majority being male (127/177, 71.7%). Doppler ultrasonography (DUS) emerged as the primary initial screening tool in 80% of studies. The hepatic arterial resistive index (RI) was a critical parameter, with mean values significantly decreasing from 0.84 pre-embolization to 0.70 post-embolization (p < 0.001). All cases confirmed technical success via digital subtraction angiography, revealing delayed hepatic arterial filling without stenosis or thrombosis. Coils were the predominant embolic agent, used in 80.8% of patients, followed by AVP in 16.3%. The overall mortality rate was 4.58%, with 29 major and 3 minor complications noted. Notably, proximal placement of coils in the splenic artery was associated with lower mortality rates compared to distal placement and showed comparable complication rates to AVPs. CONCLUSION: DUS is a reliable screening modality for NOHAH, with post-SAE assessments showing significant improvements. The choice and location of embolization significantly impact patient outcomes, with proximal placement of coils emerging as a preferable strategy due to lower mortality rates and comparable complication profiles to alternative methods.

Analysis of cell free DNA to predict outcome to bevacizumab therapy in colorectal cancer patients.

To predict outcome to combination bevacizumab (BVZ) therapy, we employed cell-free DNA (cfDNA) to determine chromosomal instability (CIN), nucleosome footprints (NF) and methylation profiles in metastatic colorectal cancer (mCRC) patients. Low-coverage whole-genome sequencing (LC-WGS) was performed on matched tumor and plasma samples, collected from 74 mCRC patients from the AC-ANGIOPREDICT Phase II trial (NCT01822444), and analysed for CIN and NFs. A validation cohort of plasma samples from the University Medical Center Mannheim (UMM) was similarly profiled. 61 AC-ANGIOPREDICT plasma samples collected before and following BVZ treatment were selected for targeted methylation sequencing. Using cfDNA CIN profiles, AC-ANGIOPREDICT samples were subtyped with 92.3% accuracy into low and high CIN clusters, with good concordance observed between matched plasma and tumor. Improved survival was observed in CIN-high patients. Plasma-based CIN clustering was validated in the UMM cohort. Methylation profiling identified differences in CIN-low vs. CIN high (AUC = 0.87). Moreover, significant methylation score decreases following BVZ was associated with improved outcome (p = 0.013). Analysis of CIN, NFs and methylation profiles from cfDNA in plasma samples facilitates stratification into CIN clusters which inform patient response to treatment.

Efficacy and Safety of Local Liver Radioablation in Hepatocellular Carcinoma Lesions within and beyond Limits of Thermal Ablation.

INTRODUCTION: CT-guided interstitial brachytherapy (iBT) radiotherapy has been established in the treatment of liver tumors. With iBT, hepatocellular carcinoma (HCC) lesions can be treated beyond the limits of thermal ablation (i.e., size and location). However, a comprehensive analysis of the efficacy of iBT in patients within and beyond thermal ablation limits is lacking. MATERIALS AND METHODS: A total of 146 patients with 216 HCC lesions have been analyzed retrospectively. Clinical and imaging follow-up data has been collected. Lesions were evaluated in terms of suitability for thermal ablation or not. The correlation between local tumor control (LTC), time to progression (TTP), overall survival (OS), and clinical and imaging parameters have been evaluated using univariable and multivariable Cox regression analyses. RESULTS: LTC rates at 12 months, 24 months, and 36 months were 87%, 75%, and 73%, respectively. 65% of lesions (n = 141) were not suitable for radiofrequency ablation (RFA). The median TTP was 13 months, and the median OS was not reached (3-year OS rate: 70%). No significant difference in LTC, TTP, or OS regarding RFA suitability existed. However, in the overall multivariable analysis, lesion diameter >5 cm was significantly associated with lower LTC (HR: 3.65, CI [1.60-8.31], p = 0.002) and shorter TTP (HR: 2.08, CI [1.17-3.70], p = 0.013). Advanced BCLC stage, Child-Pugh Stage, and Hepatitis B were associated with shorter OS. CONCLUSION: iBT offers excellent LTC rates and OS in local HCC treatment regardless of the limits of thermal ablation, suggesting further evidence of its alternative role to thermal ablation in patients with early-stage HCC.

Hsf1 and Hsf2 in normal, healthy human tissues: Immunohistochemistry provokes new questions.

The heat shock transcription factors heat shock transcription factor 1 and Hsf2 have been studied for many years, mainly in the context of stress response and in malignant cells. Their physiological function in nonmalignant human cells under nonstress conditions is still largely unknown. To approach this important issue, Joutsen et al. present immunohistochemical staining data on Hsf1 and Hsf2 in 80 nonpathological human tissue samples. The wealth of these data elicits many interesting questions that will spur many future research projects.

Usage Behaviour and Adoption Criteria for Mobile Health Solutions in Patients with Chronic Diseases in Gastroenterology.

Introduction: Mobile Health (mHealth) applications allow for new possibilities and opportunities in patient care. Their potential throughout the whole patient journey is undisputed. However, the eventual adoption by patients depends on their acceptance of and motivation to use mHealth applications as well as their adherence. Therefore, we investigated the motivation and drivers of acceptance for mHealth and developed an adapted model of the Unified Theory of Acceptance and Use of Technology (UTAUT2). Methods: We evaluated 215 patients with chronic gastroenterological diseases who answered a questionnaire including all model constructs with 7-point Likert scale items. Our model was adapted from the Unified Theory of Acceptance and Use in Technology 2 and includes influencing factors such as facilitating conditions, performance expectancy, hedonic motivation, social influence factors, effort expectancy, as well as personal empowerment and data protection concerns. Model evaluation was performed with structural equation modelling with PLS-SEM. Bootstrapping was performed for hypothesis testing. Results and Conclusion: Patients had a median age of 55.5 years, and the gender ratio was equally distributed. Forty percent received a degree from a university, college, technical academy, or engineering school. The majority of patients suffered from chronic liver disease, but patients with inflammatory bowel diseases, GI cancers, and pancreatic diseases were also included. Patients considered their general technology knowledge as medium to good or very good (78%). Actual usage of mHealth applications in general was rare, while the intention to use them was high. The leading acceptance factor for mHealth applications in our patient group was feasibility, both in terms of technical requirements and the intuitiveness and manageability of the application. Concerns about data privacy did not significantly impact the intention to use mobile devices. Neither the gamification aspect nor social influence factors played a significant role in the intention to use mHealth applications. Interpretation: Most of our patients were willing to spend time on a mHealth application specific to their disease on a regular basis. Acceptance and adherence are ensured by efficient utilization that requires minimum effort and compatible technologies as well as support in case of difficulties. Social influence and hedonic motivation, which were part of UTAUT2, as well as data security concerns, were not significantly influencing our patients' intention to use mHealth applications. A literature review revealed that drivers of acceptance vary considerably among different population and patient groups. Therefore, healthcare and mHealth providers should put effort into understanding their specific target groups' drivers of acceptance. We provided those for a cohort of patients from gastroenterology in this project.

Spatiotemporally resolved colorectal oncogenesis in mini-colons ex vivo.

Three-dimensional organoid culture technologies have revolutionized cancer research by allowing for more realistic and scalable reproductions of both tumour and microenvironmental structures1-3. This has enabled better modelling of low-complexity cancer cell behaviours that occur over relatively short periods of time4. However, available organoid systems do not capture the intricate evolutionary process of cancer development in terms of tissue architecture, cell diversity, homeostasis and lifespan. As a consequence, oncogenesis and tumour formation studies are not possible in vitro and instead require the extensive use of animal models, which provide limited spatiotemporal resolution of cellular dynamics and come at a considerable cost in terms of resources and animal lives. Here we developed topobiologically complex mini-colons that are able to undergo tumorigenesis ex vivo by integrating microfabrication, optogenetic and tissue engineering approaches. With this system, tumorigenic transformation can be spatiotemporally controlled by directing oncogenic activation through blue-light exposure, and emergent colon tumours can be tracked in real-time at the single-cell resolution for several weeks without breaking the culture. These induced mini-colons display rich intratumoural and intertumoural diversity and recapitulate key pathophysiological hallmarks displayed by colorectal tumours in vivo. By fine-tuning cell-intrinsic and cell-extrinsic parameters, mini-colons can be used to identify tumorigenic determinants and pharmacological opportunities. As a whole, our study paves the way for cancer initiation research outside living organisms.

The Legionella pneumophila effector DenR hijacks the host NRas proto-oncoprotein to downregulate MAPK signaling.

Small GTPases of the Ras subfamily are best known for their role as proto-oncoproteins, while their function during microbial infection has remained elusive. Here, we show that Legionella pneumophila hijacks the small GTPase NRas to the Legionella-containing vacuole (LCV) surface. A CRISPR interference screen identifies a single L. pneumophila effector, DenR (Lpg1909), required for this process. Recruitment is specific for NRas, while its homologs KRas and HRas are excluded from LCVs. The C-terminal hypervariable tail of NRas is sufficient for recruitment, and interference with either NRas farnesylation or S-acylation sites abrogates recruitment. Intriguingly, we detect markers of active NRas signaling on the LCV, suggesting it acts as a signaling platform. Subsequent phosphoproteomics analyses show that DenR rewires the host NRas signaling landscape, including dampening of the canonical mitogen-activated protein kinase pathway. These results provide evidence for L. pneumophila targeting NRas and suggest a link between NRas GTPase signaling and microbial infection.

Targeting KRAS Diversity: Covalent Modulation of G12X and Beyond in Cancer Therapy.

The GTPase KRAS acts as a switch in cellular signaling, transitioning between inactive GDP-bound and active GTP-bound states. In about 20% of human cancers, oncogenic RAS mutations disrupt this balance, favoring the active form and promoting proliferative signaling, thus rendering KRAS an appealing target for precision medicine in oncology. In 2013, Shokat and co-workers achieved a groundbreaking feat by covalently targeting a previously undiscovered allosteric pocket (switch II pocket (SWIIP)) of KRASG12C. This breakthrough led to the development and approval of sotorasib (AMG510) and adagrasib (MRTX849), revolutionizing the treatment of KRASG12C-dependent lung cancer. Recent achievements in targeting various KRASG12X mutants, using SWIIP as a key binding pocket, are discussed. Insights from successful KRASG12C targeting informed the design of molecules addressing other mutations, often in a covalent manner. These findings offer promise for innovative approaches in addressing commonly occurring KRAS mutations such as G12D, G12V, G12A, G12S, and G12R in various cancers.

Current Trends and Advancements in the Management of Hepatocellular Carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) remains a significant global health burden with a high mortality rate. Over the past 40 years, significant progress has been achieved in the prevention and management of HCC. SUMMARY: Hepatitis B vaccination programs, the development of direct acting antiviral drugs for Hepatitis C, and effective surveillance strategies provide a profound basis for the prevention of HCC. Advanced surgery and liver transplantation along with local ablation techniques potentially offer cure for the disease. Also, just recently, the introduction of immunotherapy opened a new chapter in systemic treatment. Finally, the introduction of the BCLC classification system for HCC, clearly defining patient groups and assigning reasonable treatment options, has standardized treatment and become the basis of almost all clinical trials for HCC. With this review, we provide a comprehensive overview of the evolving landscape of HCC management and also touch on current challenges. KEY MESSAGE: A comprehensive and multidisciplinary approach is crucial for effective HCC management. Continued research and clinical trials are imperative to further enhance treatment options and will ultimately reduce the global burden of this devastating disease.

Prioritization and Resource Allocation in the Context of the COVID-19 Pandemic: Recommendations for Colorectal and Pancreatic Cancer in Germany.

In the context of the COVID-19 pandemic, there has been a scarcity of resources with various effects on the care of cancer patients. This paper provides an English summary of a German guideline on prioritization and resource allocation for colorectal and pancreatic cancer in the context of the pandemic. Based on a selective literature review as well as empirical and ethical analyses, the research team of the CancerCOVID Consortium drafted recommendations for prioritizing diagnostic and treatment measures for both entities. The final version of the guideline received consent from the executive boards of nine societies of the Association of Scientific Medical Societies in Germany (AWMF), 20 further professional organizations and 22 other experts from various disciplines as well as patient representatives. The guiding principle for the prioritization of decisions is the minimization of harm. Prioritization decisions to fulfill this overall goal should be guided by (1) the urgency relevant to avoid or reduce harm, (2) the likelihood of success of the diagnostic or therapeutic measure advised, and (3) the availability of alternative treatment options. In the event of a relevant risk of harm as a result of prioritization, these decisions should be made by means of a team approach. Gender, age, disability, ethnicity, origin, and other social characteristics, such as social or insurance status, as well as the vehemence of a patient's treatment request and SARS-CoV-2 vaccination status should not be used as prioritization criteria. The guideline provides concrete recommendations for (1) diagnostic procedures, (2) surgical procedures for cancer, and (3) systemic treatment and radiotherapy in patients with colorectal or pancreatic cancer within the context of the German healthcare system.

Myotubularin-related-protein-7 inhibits mutant (G12V) K-RAS by direct interaction.

Inhibition of K-RAS effectors like B-RAF or MEK1/2 is accompanied by treatment resistance in cancer patients via re-activation of PI3K and Wnt signaling. We hypothesized that myotubularin-related-protein-7 (MTMR7), which inhibits PI3K and ERK1/2 signaling downstream of RAS, directly targets RAS and thereby prevents resistance. Using cell and structural biology combined with animal studies, we show that MTMR7 binds and inhibits RAS at cellular membranes. Overexpression of MTMR7 reduced RAS GTPase activities and protein levels, ERK1/2 phosphorylation, c-FOS transcription and cancer cell proliferation in vitro. We located the RAS-inhibitory activity of MTMR7 to its charged coiled coil (CC) region and demonstrate direct interaction with the gastrointestinal cancer-relevant K-RASG12V mutant, favouring its GDP-bound state. In mouse models of gastric and intestinal cancer, a cell-permeable MTMR7-CC mimicry peptide decreased tumour growth, Ki67 proliferation index and ERK1/2 nuclear positivity. Thus, MTMR7 mimicry peptide(s) could provide a novel strategy for targeting mutant K-RAS in cancers.