The activation of the Notch pathway promotes the occurrence and progression of breast cancer. The Notch signal plays different roles in different molecular subtypes of breast cancer. In estrogen receptor-positive (ER+) breast cancer, the Notch pathway regulates the activity of estrogen receptors. In human epidermal growth factor receptor 2-positive (HER2+) breast cancer, crosstalk between Notch and HER2 enhances HER2 signal expression. In triple-negative breast cancer (TNBC), Notch pathway activation is closely linked to tumor invasion and drug resistance. This article offers a comprehensive review of the structural domains, biological functions, and key targets of Notch with a specific focus on the roles of Furin protease, ADAM metalloprotease, and γ-secretase in breast cancer and their potential as therapeutic targets. We discuss the functions and mutual regulatory mechanisms of these proteinases in the Notch pathway as well as other potential targets in the Notch pathway, such as the glycosylation process and key transcription factors. This article also introduces new approaches in the treatment of breast cancer, with a special focus on the molecular characteristics and treatment response differences of different subtypes. We propose that the core regulatory molecules of the Notch pathway may become key targets for development of personalized treatment, which may significantly improve treatment outcomes and prognosis for patients with breast cancer.

UNASSIGNED: Vitamin D/Vitamin D receptor (VD/VDR) signaling and the Notch pathway are involved in intestinal barrier restoration in colitis; however, their relationship and underlying mechanism are largely unknown. Therefore, this study aimed to investigate the role and mechanism of VD/VDR and the Notch pathways in intestinal barrier protection.
UNASSIGNED: Genetic Vdr knockout (VDR KO) and VD deficient (VDd) mice were established, and colitis was induced by feeding 2.5% dextran sodium sulfate (DSS) water. Mechanistic studies, including real-time PCR, immunofluorescence, Western blotting and dual-luciferase reporter assays, were performed on cultured Caco-2 cells and intestinal organoids.
UNASSIGNED: VD deficiency and VDR genetical KO increased the severity of DSS-induced colitis in mice, which presented a higher disease activity index score, increased intestinal permeability, and more severe intestinal histological damage than controls, accompanied by decreased and disrupted claudin-1 and claudin-3. Moreover, inhibition of Notch pathway by LY411,575 aggravated the severity of DSS-induced colitis and intestinal injury. In Caco-2 cells and intestinal organoids, the expression of Notch-1, N1ICD and Hes1 decreased upon downregulation or KO of VDR but increased upon paricalcitol (PAR, a VDR agonist) treatment. Meanwhile, PAR rescued claudin-1 and claudin-3 impairments that resulted from TNF-α exposure but failed to restore claudin-3 upon Notch inhibition. The dual-luciferase reporter assay further suggested that VD/VDR positively regulated the Notch signaling pathway by modulating Notch-1 transcription.
UNASSIGNED: VD/VDR positively modulates Notch activation by promoting Notch-1 transcription to maintain intestinal tight junction integrity and barrier function. This highlights the VD/VDR-Notch pathway as a potential new therapeutic target for protecting the intestinal barrier against ulcerative colitis.

BACKGROUND: LARC patients commonly receive adjuvant therapy, however, hidden micrometastases still limit the improvement of OS. This study aims to investigate the impact of VASN in rectal cancer with pulmonary metastasis and understand the underlying molecular mechanisms to guide adjuvant chemotherapy selection.
METHODS: Sequencing data from rectal cancer patients with pulmonary metastasis from Sun Yat-sen University Cancer Center (SYSUCC) and publicly available data were meticulously analyzed. The functional role of VASN in pulmonary metastasis was validated in vivo and in vitro. Coimmunoprecipitation (co-IP), immunofluorescence, and rescue experiments were conducted to unravel potential molecular mechanisms of VASN. Moreover, VASN expression levels in tumor samples were examined and analyzed for their correlations with pulmonary metastasis status, tumor stage, adjuvant chemotherapy benefit, and survival outcome.
RESULTS: Our study revealed a significant association between high VASN expression and pulmonary metastasis in LARC patients. Experiments in vitro and in vivo demonstrated that VASN could promote the cell proliferation, metastasis, and drug resistance of colorectal cancer. Mechanistically, VASN interacts with the NOTCH1 protein, leading to concurrent activation of the NOTCH and MAPK pathways. Clinically, pulmonary metastasis and advanced tumor stage were observed in 90% of VASN-positive patients and 53.5% of VASN-high patients, respectively, and VASN-high patients had a lower five-year survival rate than VASN-low patients (26.7% vs. 83.7%). Moreover, the Cox analysis and OS analysis indicated that VASN was an independent prognostic factor for OS (HR = 7.4, P value < 0.001) and a predictor of adjuvant therapy efficacy in rectal cancer.
CONCLUSIONS: Our study highlights the role of VASN in decreasing drug sensitivity and activating the NOTCH and MAPK pathways, which leads to tumorigenesis and pulmonary metastasis. Both experimental and clinical data support that rectal cancer patients with VASN overexpression detected in biopsies have a higher risk of pulmonary metastasis and adjuvant chemotherapy resistance.

Drosophila melanogaster crystal cells are a specialized type of blood cells for innate immune process upon injury. Under normal conditions, crystal cells rarely proliferate and constitute a small proportion of fly blood cells. Notch signaling has been known to guide the cell fate determination of crystal cells and maintain their survival. Here, we reported that protein phosphatase V (PpV), the unique catalytic subunit of protein phosphatase 6 in Drosophila, is a novel regulator of crystal cell proliferation and integrity. We found that PpV proteins highly accumulated in crystal cells in the larval hematopoietic organ termed the lymph gland. Silencing PpV using RNA interference led to increased crystal cell proliferation in a Notch-independent manner and induced crystal cell rupture dependent on Notch signaling. Moreover, additive PpV prevented the rupture of crystal cells in lymph glands upon a needle injury, suggesting the involvement of PpV in wound healing. Altogether, our results indicated that PpV plays a dual role in lymph glands, preventing crystal cell proliferation to limit the cell number, as well as inhibiting crystal cell rupture to maintain their survival.

Doxorubicin (DOX) is an effective chemotherapeutic drug; however, its cardiotoxicity and resistance compromise its therapeutic index. The Notch pathway was reported to contribute to DOX cancer resistance. The role of Notch pathway in DOX cardiotoxicity has not been identified yet. Notch receptors are characterized by their extracellular (NECD) and intracellular (NICD) domains (NICD). The γ-secretase enzyme helps in the release of NICD. Dibenzazepine (DBZ) is a γ-secretase inhibitor. The present study investigated the effect of Notch pathway inhibition on DOX cardiotoxicity. Twenty-four male Wistar rats were divided into four groups: control group, DOX group, acute cardiotoxicity was induced by a single dose of DOX (20 mg/kg) i.p., DOX (20 mg/kg) plus DBZ group, and DBZ group. The third and fourth groups received i.p. injection of DBZ daily for 14 days at 2 mg/kg dose. DOX cardiotoxicity increased the level of serum creatine kinase-MB and cardiac troponin I, and it was confirmed by the histopathological examination. Moreover, the antioxidants glutathione peroxidase and superoxide dismutase levels were markedly decreased, and the inflammatory markers, inducible nitric oxide synthase, nuclear factor-ķB, and tumor necrosis factor-α were markedly increased. Furthermore, DOX increased BAX protein and downregulated BCL-2. In addition, DOX upregulated Notch pathway-related parameters: Hes1 and Hey1 mRNA levels, and increased Hes1 protein levels. DBZ ameliorated DOX-induced cardiotoxicity, evidenced by reducing the cardiac injury biomarkers, improving cardiac histopathological changes, correcting antioxidant levels, and reducing inflammatory and apoptotic proteins. Our study indicates the protective effect of Notch inhibitor against DOX-induced cardiotoxicity.

The study by Feeney et al. provides critical insights into the prognostic implications of NOTCH pathway activation in adenoid cystic carcinoma (ACC), particularly after disease recurrence. Utilizing both next-generation sequencing and immunohistochemistry, the research delineates the survival outcomes between NOTCH-activated and non-activated ACC groups, highlighting poorer outcomes in the former. The findings advocate for the targeted therapeutic approach and suggest a potential for personalized treatment strategies, emphasizing the need for further research into NOTCH pathway inhibitors and their clinical applications.

Primary cultured odontoblasts rapidly lose their tissue-specific phenotype. To identify transcription factors (TF) that are important for the maintenance of the odontoblast phenotype, primary cultures of C57BL/6 J mouse dental mesenchymal cells (DMC) were isolated, and expression of TF and odontoblast marker genes in cells immediately after isolation and 2 days after culture were comprehensively evaluated and compared using RNA-sequencing (RNA-seq). The expression of odontoblast markers in mouse dental mesenchymal cells decreased rapidly after isolation. In addition, the expression of Hedgehog-related, Notch-related, and immediate- early gene (IEG)-related transcription factors significantly decreased. Forced expression of these genes in lentiviral vectors, together with fibroblast growth factor 4 (FGF4), fibroblast growth factor 9 (FGF9), and the Wnt pathway activator CHIR99021, significantly induced the expression of odontogenic marker genes. These results indicate, for the first time, that Notch signaling and early genes may be important for maintaining odontoblast cultures. Furthermore, simultaneous stimulation of FGF, Wnt, Hedgehog, Notch pathways, and IEG transcription factors cooperatively promoted the maintenance of the odontoblast phenotype. These results suggest that the Hedgehog and Notch signaling pathways may play an important role in maintaining odontoblast phenotypes, in addition to FGF and Wnt signaling.

Radiation therapy (RT) is a common treatment for lung cancer. Still, it can lead to irreversible loss of pulmonary function and a significant reduction in quality of life for one-third of patients. Preexisting comorbidities, such as chronic obstructive pulmonary disease (COPD), are frequent in patients with lung cancer and further increase the risk of complications. Because lung stem cells are crucial for the regeneration of lung tissue following injury, we hypothesized that airway stem cells from patients with COPD with lung cancer might contribute to increased radiation sensitivity. We used the air-liquid interface model, a three-dimensional (3D) culture system, to compare the radiation response of primary human airway stem cells from healthy and patients with COPD. We found that COPD-derived airway stem cells, compared to healthy airway stem cell cultures, exhibited disproportionate pathological mucociliary differentiation, aberrant cell cycle checkpoints, residual DNA damage, reduced survival of stem cells and self-renewal, and terminally differentiated cells post-irradiation, which could be reversed by blocking the Notch pathway using small-molecule γ-secretase inhibitors. Our findings shed light on the mechanisms underlying the increased radiation sensitivity of COPD and suggest that airway stem cells reflect part of the pathological remodeling seen in lung tissue from patients with lung cancer receiving thoracic RT.

We describe a next-generation Drosophila protein interaction map-\"DPIM2\"-established from affinity purification-mass spectrometry of 5,805 baits, covering the largest fraction of the Drosophila proteome. The network contains 32,668 interactions among 3,644 proteins, organized into 632 clusters representing putative functional modules. Our analysis expands the pool of known protein interactions in Drosophila, provides annotation for poorly studied genes, and postulates previously undescribed protein interaction relationships. The predictive power and functional relevance of this network are probed through the lens of the Notch signaling pathway, and we find that newly identified members of complexes that include known Notch modifiers can also modulate Notch signaling. DPIM2 allows direct comparisons with a recently published human protein interaction network, defining the existence of functional interactions conserved across species. Thus, DPIM2 defines a valuable resource for predicting protein co-complex memberships and functional associations as well as generates functional hypotheses regarding specific protein interactions.

Background: Cancer development involves alterations in key cellular pathways, with aspartate β-hydroxylase (ASPH) emerging as an important player in tumorigenesis. ASPH is upregulated in various cancer types, where it promotes cancer progression mainly by regulating the Notch1 and SRC pathways. Methods: This study explored the responses of various human cervical, pharyngeal, and breast tumor cell lines to second- and third-generation ASPH inhibitors (MO-I-1151 and MO-I-1182) using proliferation, migration, and invasion assays; western blotting; and cell cycle analysis. Results: ASPH inhibition significantly reduced cell proliferation, migration, and invasion and disrupted both the canonical and noncanonical Notch1 pathways. The noncanonical pathway was particularly mediated by AKT signaling. Cell cycle analysis revealed a marked reduction in cyclin D1 expression, further confirming the inhibitory effect of ASPH inhibitors on cell proliferation. Additional analysis revealed G0/G1 arrest and restricted progression into S phase, highlighting the regulatory impact of ASPH inhibitors on the cell cycle. Furthermore, ASPH inhibition induced distinctive alterations in nuclear morphology. The high heterogeneity in the responses of individual tumor cell lines to ASPH inhibitors, both quantitatively and qualitatively, underscores the complex network of mechanisms that are regulated by ASPH and influence the efficacy of ASPH inhibition. The effects of ASPH inhibitors on Notch1 pathway activity, cyclin D1 expression, and nuclear morphology contribute to the understanding of the multifaceted effects of these inhibitors on cancer cell behavior. Conclusion: This study not only suggests that ASPH inhibitors are effective against tumor cell progression, in part through the induction of cell cycle arrest, but also highlights the diverse and heterogeneous effects of these inhibitors on the behavior of tumor cells of different origins.