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Lung diseases rank third in terms of mortality and represent a significant economic burden globally. Scientists have been conducting research to better understand respiratory diseases and find treatments for them. An ideal in vitro model must mimic the in vivo organ structure, physiology, and pathology. Organoids are self-organizing, three-dimensional (3D) structures originating from adult stem cells, embryonic lung bud progenitors, embryonic stem cells (ESCs), and induced pluripotent stem cells (iPSCs). These 3D organoid cultures may provide a platform for exploring tissue development, the regulatory mechanisms related to the repair of lung epithelia, pathophysiological and immunomodulatory responses to different respiratory conditions, and screening compounds for new drugs. To create 3D lung organoids in vitro, both co-culture and feeder-free methods have been used. However, there exists substantial heterogeneity in the organoid culture methods, including the sources of AT2 cells, media composition, and feeder cell origins. This article highlights the currently available methods for growing AT2 organoids and prospective improvements to improve the available culture techniques/conditions. Further, we discuss various applications, particularly those aimed at modeling human distal lung diseases and cell therapy.

Endocrine therapy is the main treatment for hormone receptor-positive (HR+) breast cancer. However, advanced tumors develop resistance to endocrine therapy, rendering it ineffective as the disease progresses. There are several molecular mechanisms of primary and secondary endocrine resistance. Resistance can develop due to either alteration of the estrogen receptor pathway (e.g., ESR1 mutations) or upstream growth factors signaling pathways (e.g., PI3K/Akt/mTOR pathway). Despite progress in the development of molecularly targeted anticancer therapies, the emergence of resistance remains a major limitation and an area of unmet need. In this article, we review the mechanisms of acquired endocrine resistance in HR+ advanced breast cancer and discuss current and future investigational therapeutic approaches.

BACKGROUND: Patients with heart failure (HF) with preserved ejection fraction (HFpEF) and obesity experience a high burden of symptoms and functional impairment, and a poor quality of life. In the STEP-HFpEF trial (Research Study to Investigate How Well Semaglutide Works in People Living With Heart Failure and Obesity), once-weekly semaglutide 2.4 mg improved symptoms, physical limitations, and exercise function, and reduced inflammation and body weight. This prespecified analysis investigated the effects of semaglutide on the primary and confirmatory secondary end points across the range of the Kansas City Cardiomyopathy Questionnaire (KCCQ) scores at baseline and on all key summary and individual KCCQ domains. METHODS: STEP-HFpEF randomly assigned 529 participants with symptomatic HF, an ejection fraction of ≥45%, and a body mass index of ≥30 kg/m 2 to once-weekly semaglutide 2.4 mg or placebo for 52 weeks. Dual primary end points change in KCCQ-Clinical Summary Score (CSS) and body weight. Confirmatory secondary end points included change in 6-minute walk distance, a hierarchical composite end point (death, HF events, and change in KCCQ-CSS and 6-minute walk distance) and change in C-reactive protein. Patients were stratified by KCCQ-CSS tertiles at baseline. Semaglutide effects on the primary, confirmatory secondary, and select exploratory end points (N-terminal pro-brain natriuretic peptide) were examined across these subgroups. Semaglutide effects on additional KCCQ domains (Total Symptom Score [including symptom burden and frequency], Physical Limitations Score, Social Limitations Score, Quality of Life Score, and Overall Summary Score) were also evaluated. RESULTS: Baseline median KCCQ-CSS across tertiles was 37, 59, and 77 points, respectively. Semaglutide consistently improved primary end points across KCCQ tertiles 1 to 3 (estimated treatment differences [95% CI]: for KCCQ-CSS, 10.7 [5.4 to 16.1], 8.1 [2.7 to 13.4], and 4.6 [–0.6 to 9.9] points; for body weight, –11 [–13.2 to –8.8], –9.4 [–11.5 to –7.2], and –11.8 [–14.0 to –9.6], respectively; P interaction =0.28 and 0.29, respectively); the same was observed for confirmatory secondary and exploratory end points ( P interaction >0.1 for all). Semaglutide-treated patients experienced improvements in all key KCCQ domains (estimated treatment differences, 6.7–9.6 points across domains; P ≤0.001 for all). Greater proportion of semaglutide-treated versus placebo-treated patients experienced at least 5-, 10-, 15-, and 20-point improvements in all KCCQ domains (odds ratios, 1.6–2.9 across domains; P <0.05 for all). CONCLUSIONS: In patients with HFpEF and obesity, semaglutide produced large improvements in HF-related symptoms, physical limitations, exercise function, inflammation, body weight, and N-terminal pro-brain natriuretic peptide, regardless of baseline health status. The benefits of semaglutide extended to all key KCCQ domains. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04788511.

Abstract INTRODUCTION Belzutifan is a selective inhibitor of hypoxia-inducible factor 2-alpha that has been FDA approved for Von Hippel–Lindau (VHL) syndrome-associated tumors. There is limited real-world evidence in CNS hemangioblastoma. Our objective was to report on our clinical experience with belzutifan. METHODS We retrospectively reviewed our institutional (Mayo Clinic Rochester) experience of belzutifan in adults (18 years or older) with VHL and craniospinal hemangioblastomas not amenable to surgery. The study period was October 2021 to March 2023. RESULTS 4 patients (all female) with a median age of 36 years at time of belzutifan initiation were included. Median duration of therapy at last follow-up was 11 months (6-17 months). All patients had radiographic response to therapy after a median of 3 months (2-5 months), with maximal response to therapy after a median of 8 months (3-17 months). Therapy was well tolerated. The most common adverse effect was anemia. No patients had treatment pauses or dose adjustments due to toxicity. No patients experienced hypoxia. DISCUSSION We showed that belzutifan is safe and well-tolerated with strong disease response for CNS hemangioblastoma in adults with VHL, supporting continued use of belzutifan in this patient population. Future studies should assess duration of treatment, effects of cessation after long-term use, and markers of therapeutic response.

Abstract Methylation profiling has revealed unexpected relationships between traditional histopathology-based versus biologically-based classifications of brain tumors. Methylation class pleomorphic xanthoastrocytoma (mcPXA) comprises tumors with the same methylation signature as classical PXA but with additional morphologic patterns, including overlap with glioblastoma (GBM). To characterize mcPXA, we examined epidemiologic, histologic, and molecular features as well as clinical behavior of a cohort (n=313) of tumors matching to mcPXA by the DKFZ classifier (v12 score &gt;= 0.85). Patient median age was 19 (range 1-73) with a female predominance (178 female/135 male). CDKN2A/B homozygous deletion was observed in 273 (87%) cases. In the subset of cases tested for BRAF p.V600E (n=120), 111 (93%) harbored the mutation. Concomitant chr7+/chr10- was observed in 66 (21%) cases. In the subset of cases tested for TERT promoter mutations (n=50), 11 (22%) harbored the mutation, always with co-occurrence of BRAF p.V600E (11/11) and infrequently with chr7+/chr10- (3/11). MGMT promoter methylation was observed in 40 (13%) cases. Overall and progression-free survival (OS, PFS) in mcPXA were similar to grade 2-3 IDH-mutant astrocytoma (A-IDH). Prognostic factors in mcPXA included GBM-like histopathology (defined as cases diagnosed as GBM prior to methylation profiling), concomitant chr7+/chr10-, and MGMT promoter methylation. GBM-like histopathology was associated with shorter OS (p=0.02) and PFS (p&lt; 0.01) compared to cases without GBM-like histopathology. Concomitant chr7+/chr10- was associated with shorter PFS (p=0.02), and MGMT promoter methylation was associated with shorter OS (p=0.03). Our findings demonstrate that mcPXA tumors affect adolescents and young adults, share molecular features of classical PXA, and manifest clinical behavior similar to classical PXA, but subsets of tumors with atypical features (chr7+/chr10-, MGMT promoter methylation, and/or GBM-like histopathology) are more aggressive. The use of a molecular definition of PXA reveals that this tumor type is more common than previously appreciated and warrants in-depth study for therapeutic options.

Abstract Histopathology is the gold standard for distinguishing tumor recurrence from treatment-induced necrosis but differentiating pseudoprogression from true recurrence is challenging in tumors with ambiguous morphological features. Prior research reported a 36% inter-rater agreement during suspected recurrence (Holdhoff et al., 2019). While serial radiographic and laboratory assessments are common, serial histopathological assessments are not. This study evaluated agreement and factors influencing assessment of active and inactive tumors through single and multiple time-point histopathological assessments. Patients who underwent initial and subsequent reoperation were identified, and their available histology slides were examined retrospectively. Four independent neuropathologists conducted two types of reviews: single time-point reviews using most recent biopsy/surgery slides, and multiple time-point reviews comparing images from initial and repeat biopsies taken 1-3 months apart. Neuropathologists completed a questionnaire assessing various tumor characteristics. Assignments were categorized as "active tumor," "treatment effect," or "unable to classify." 324 assessments were conducted (108 single time-point, 216 multiple time-point). Intraclass correlation coefficients for single vs. multiple time-point assessments were 0.72-0.93 for active tumors and 0.57-0.86 for inactive tumors. Pathologists' assessment of % inactive tumor was influenced by mitotic activity (p= 0.0028), cellularity (p&lt; 0.0001), hyalinized vessels (p= 0.0019), and necrosis (p= 0.0046). Evaluation of % active tumor was influenced by hyalinized vessels (p= 0.0006), mitotic activity (p&lt; 0.0001), cellularity (p&lt; 0.0001), and microvascular proliferation (p= 0.0093), with the latter three factors specifically affecting final sign-out pathology. Serial histopathological assessment didn’t affect determination of % active or inactive tumor. No association between % inactive tumor and fibrinoid necrosis for single time-point (p= 0.34) but a strong negative association was seen for serial assessment (p= 0.0006). Inter-rater agreement was higher for identifying active tumors than inactive tumors in both case reviews. Changes in necrosis between tissue samples in single vs. multiple timepoint assessments influenced pathologists' assessment of % inactive tumor.

Abstract Glioblastoma (GBM) is the most common and lethal primary brain tumor in adults, despite current treatment options. One of the major contributing factors to this dismal outcome is a subset of cells called glioma stem cells (GSCs) that are highly tumorigenic, invasive, and resistant to conventional treatments. Thus, studies that focus on the properties of GSC biology are needed to develop novel therapies to improve overall survival. Here we report a novel role of STAT5 in GSC stemness and survival. In GBM tumors, STAT5 has been shown to be active in the infiltrative, residual population of cells remaining post-surgery. Knockdown of STAT5 results in the decrease in GSC stemness and therapeutic resistance. Interestingly, we find that expression of OLIG2, a key cell fate factor important for the tumorigenic potential of GSCs, affects STAT5 activation with a positive correlation between OLIG2 and STAT5 mRNA expression in GBM tumors. Furthermore, we find that in GSCs expressing EGFRvIII, STAT5 interacts with OLIG2 and pharmacological inhibition of STAT5 activation or knockdown of STAT5 expression results in decrease of OLIG2-mediated GSC invasion. Together, these data suggest a novel transcriptional complex, STAT5-OLIG2, in the potential role for GSC survival, maintenance, and invasion.

Abstract It has been widely acknowledged that limited access to the human brain, along with the importance of its structures, presents significant challenges in obtaining brain tumor tissue. This poses difficulties for clinical decision-making, as healthcare professionals often have to rely solely on imaging to address complex problems. There is currently no definitive method to make these decisions other than relying on informed yet subjective human judgment. That said, imaging abnormalities are a result of a presence of particular tumor-related biology. Because of this, and the heterogeneity frequently observed in brain tumors, we have developed an image-localized biopsy protocol that has been employed for research purposes at Mayo Clinic Arizona for over five years. This multidisciplinary approach involves the collaborative efforts from neurosurgeons, neuro-oncologists, scrub-techs, nurses, radiologists, as well as multiple research labs, all working within a well-established pipeline. The implementation of this protocol has allowed us to obtain image-localized biopsies during surgical procedures, enabling the correlation of local imaging findings with corresponding tissue features through the utilization of machine learning models. The primary objective of this endeavor is to enhance our understanding of the underlying biological mechanisms of brain tumors based on patients' imaging data. This protocol has been successful for our research purposes, and with minor adjustments, it can be readily adopted by any hospital in order to collect more data about these incredibly heterogeneous diseases. While the use of neuronavigation during surgery has become commonplace in many medical institutions, localization of tissue samples is not. Utilizing pre-existing infrastructure in the operating room is a small burden with big potential positive outcomes. Sample locations can be useful to clinicians during tumor board discussions, to better assess disease heterogeneity. These minor refinements in the surgical workflow have the capacity to provide clinicians with additional clinically-relevant data without disrupting patient care.