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Epithelial GREMLIN1 disrupts intestinal epithelial-mesenchymal crosstalk to induce a wnt-dependent ectopic stem cell niche through stromal remodelling.
In homeostasis, counterbalanced morphogen signalling gradients along the vertical axis of the intestinal mucosa regulate the fate and function of epithelial and stromal cell compartments. Here, we use a disease-positioned mouse and human tissue to explore the consequences of pathological BMP signalling dysregulation on epithelial-mesenchymal interaction. Aberrant pan-epithelial expression of the secreted BMP antagonist Grem1 results in ectopic crypt formation, with lineage tracing demonstrating the presence of Lgr5(-) stem/progenitor cells. Isolated epithelial cell Grem1 expression has no effect on individual cell fate, indicating an intercompartmental impact of mucosal-wide BMP antagonism. Treatment with an anti-Grem1 antibody abrogates the polyposis phenotype, and triangulation of specific pathway inhibitors defines a pathological sequence of events, with Wnt-ligand-dependent ectopic stem cell niches forming through stromal remodelling following BMP disruption. These data support an emerging co-evolutionary model of intestinal cell compartmentalisation based on bidirectional regulation of epithelial-mesenchymal cell fate and function.
Impact of Long-Term Chemotherapy on Outcomes in Pancreatic Ductal Adenocarcinoma: A Real-World UK Multi-Centre Study
Background: We reviewed outcomes of short and long-term chemotherapy with or without breaks in pancreatic ductal adenocarcinoma (PDAC) patients. Methods: PDAC patients receiving ≥3 chemotherapy cycles between 2019 and 2024 at three institutions were included. Progression-free survival after first-line chemotherapy (PFS1), overall survival (OS) and best overall response (BOR) to chemotherapy were assessed using the Wilcoxon test, Kaplan–Meier test, and univariate and multivariate Cox regression models. Results: We screened 237 patients, and 135 patients met the study criteria. Among these patients, 25 had resectable disease, and 110 had unresectable/metastatic disease (13% borderline resectable (BRPC), 20% locally advanced (LAPC), 10% localised developing metastases, 57% de novo metastatic). Ten patients (7%) underwent genetic profiling; KRAS aberrations (N = 4), actionable PLAB2/BRCA2/FGFR2 mutations (N = 3), ATM/BRIP1 alteration (N = 1). Two patients were managed with PARP inhibitors after receiving multiple lines of chemotherapy. Median PFS1 and OS were concordant with the published literature, but select patient groups achieved prolonged survival outcomes. Among the 36 BRPC/LAPC patients, we observed >1-year PFS1 in 9 (25%) patients and >2-year OS in 3 (8%) patients. Among the 63 de novo metastatic patients, we observed >1-year PFS1 and >2-year OS in 6 (10%) patients. Among patients with localised disease, smoking history was a poor prognostic factor with respect to OS (p = 0.03). Improved PFS1 and OS was associated with ≥6 cycles of first-line chemotherapy, its duration of ≥3.66 months, and local treatment after first chemotherapy (p < 0.05 for all). Stereotactic body radiotherapy following first-line chemotherapy was delivered in N = 6 (27%) and N = 1 (7%) of patients with LAPC and BRPC, respectively. Chemotherapy interruption duration, but not number, was associated with PFS1 and OS only in the localised cohort (p < 0.05). In patients with de novo metastatic disease, prevalence of type 2 diabetes was adversely associated with OS (p = 0.03). Improved PFS and OS was associated with ≥6 cycles of first-line chemotherapy, its duration of ≥4.37 months, and BOR to it (only in this cohort) (p < 0.05 for all). A favourable OS was associated with >1 line of chemotherapy (p = 0.003). Conclusion: Despite challenges, extended chemotherapy and multiple treatment lines may improve survival, with localised treatments benefiting select patients.
A Novel Primary Cell Line Model of Localized Prostate Cancer and Radioresistance—A Role for Nicotinamide N-Methyltransferase
Prostate cancer cell lines are particularly clinically homogenous, mostly representing metastatic states rather than localized disease. While there has been significant work in the development of additional models, few have been created without oncogenic transformation. We derived a primary prostate cancer cell line from a patient with localized Gleason 7 prostate cancer—designated CaB34—which spontaneously immortalized. We leveraged CaB34 to generate a paired radioresistant subline, CaB34-CF, using a clinically relevant fractionated radiotherapy schedule. These two paired cell lines were investigated extensively to determine their molecular characteristics and therapy responses. Both CaB34 and CaB34-CF express prostate-specific markers, including KRT18, NKX3.1, and AMACR. Multi-omic analyses using RNAseq and shotgun proteomics identified NNMT as the most significantly dysregulated component in CaB34-CF. A bioinformatic analysis determined that NNMT was more abundant within prostate tumors compared to benign prostate, suggesting a role in tumor progression. Knockdown studies of NNMT demonstrated significant radiosensitization of CaB34-CF cells, which was largely a result of increased radiation-induced cellular senescence. Growth as 3D organoids was significantly higher in the CaB34-CF line, and demonstrated a less structured pattern of expression of cytokeratin markers. Radiosensitization with NNMT siRNA was recapitulated in a 3D organoid clonogenic assay in CaB34-CF cells. Our research provides a paired primary model of treatment-naïve and radioresistant disease to address mechanisms of therapy resistance, while expanding the repertoire of localized prostate cancer cell lines for the research community. In addition, our findings present NNMT as a potential therapeutic target for sensitization of radioresistant disease.
Preferences for multi-cancer tests (MCTs) in primary care: discrete choice experiments of general practitioners and the general public in England
Abstract Background Multi-Cancer tests (MCTs) hold potential to detect cancer across multiple sites and some predict the origin of the cancer signal. Understanding stakeholder preferences for MCTs could help to develop appealing MCTs, encouraging their adoption. Methods Discrete Choice Experiments (DCEs) conducted online in England. Results GPs (n = 251) and the general public (n = 1005) preferred MCTs that maximised negative predictive value, positive predictive value, and could test for a larger number of cancer sites. A reduction of the NPV of 4.0% was balanced by a 12.5% increase in the PPV for people and a 32.5% increase in PPV for GPs. People from ethnic minority backgrounds placed less importance on whether MCTs can detect multiple cancers. People with more knowledge and experience of cancer placed substantial importance on the MCT being able to detect cancer at an early stage. Both GPs and members of the public preferred the MCT reported in the SYMPLIFY study to FIT, PSA, and CA125, and preferred the SYMPLIFY MCT to 91% (GPs) and 95% (people) of 2048 simulated MCTs. Conclusions These findings provide a basis for designing clinical implementation strategies for MCTs, according to their performance characteristics.
Serum- and Glucocorticoid-induced Kinase Sgk1 Directly Promotes the Differentiation of Colorectal Cancer Cells and Restrains Metastasis.
PURPOSE: The molecular events that determine intestinal cell differentiation are poorly understood and it is unclear whether it is primarily a passive event or an active process. It is clinically important to gain a greater understanding of the process, because in colorectal cancer, the degree of differentiation of a tumor is associated with patient survival. SGK1 has previously been identified as a gene that is principally expressed in differentiated intestinal cells. In colorectal cancer, there is marked downregulation of SGK1 compared with normal tissue.Experimental Design: An inducible SGK1 viral overexpression system was utilized to induce reexpression of SGK1 in colorectal cancer cell lines. Transcriptomic and phenotypic analyses of these colorectal cancer lines was performed and validation in mouse and human cohorts was performed. RESULTS: We demonstrate that SGK1 is upregulated in response to, and an important controller of, intestinal cell differentiation. Reexpression of SGK1 in colorectal cancer cell lines results in features of differentiation, decreased migration rates, and inhibition of metastasis in an orthotopic xenograft model. These effects may be mediated, in part, by SGK1-induced PKP3 expression and increased degradation of MYC. CONCLUSIONS: Our results suggest that SGK1 is an important mediator of differentiation of colorectal cells and may inhibit colorectal cancer metastasis.
Microenvironmental control of stem cell fate in intestinal homeostasis and disease.
The conventional model of intestinal epithelial architecture describes a unidirectional tissue organizational hierarchy with stem cells situated at the crypt base and daughter cells proliferating and terminally differentiating as they progress along the vertical (crypt-luminal) axis. In this model, the fate of a cell that has left the niche is determined and its lifespan limited. Evidence is accumulating to suggest that stem cell control and daughter cell fate determination is not solely an intrinsic, cell autonomous property but is heavily influenced by the microenvironment including paracrine, mesenchymal, and endogenous epithelial morphogen gradients. Recent research suggests that in intestinal homeostasis, stem cells transit reversibly between states of variable competence in the niche. Furthermore, selective pressures that disrupt the homeostatic balance, such as intestinal inflammation or morphogen dysregulation, can cause committed progenitor cells and even some differentiated cells to regain stem cell properties. Importantly, it has been recently shown that this disruption of cell fate determination can lead to somatic mutation and neoplastic transformation of cells situated outside the crypt base stem cell niche. This paper reviews the exciting developments in the study of stem cell dynamics in homeostasis, intestinal regeneration, and carcinogenesis, and explores the implications for human disease and cancer therapies.