Nicotine promotes tumor progression and epithelial-mesenchymal transition by regulating the miR-155-5p/NDFIP1 axis in pancreatic ductal adenocarcinoma

NEDD4 and NEDD4L: Ubiquitin Ligases Closely Related to Digestive Diseases

Protein ubiquitination is an enzymatic cascade reaction and serves as an important protein post-translational modification (PTM) that is involved in the vast majority of cellular life activities. The key enzyme in the ubiquitination process is E3 ubiquitin ligase (E3), which catalyzes the binding of ubiquitin (Ub) to the protein substrate and influences substrate specificity. In recent years, the relationship between the subfamily of neuron-expressed developmental downregulation 4 (NEDD4), which belongs to the E3 ligase system, and digestive diseases has drawn widespread attention. Numerous studies have shown that NEDD4 and NEDD4L of the NEDD4 family can regulate the digestive function, as well as a series of related physiological and pathological processes, by controlling the subsequent degradation of proteins such as PTEN, c-Myc, and P21, along with substrate ubiquitination. In this article, we reviewed the appropriate functions of NEDD4 and NEDD4L in digestive diseases including cell proliferation, invasion, metastasis, chemotherapeutic drug resistance, and multiple signaling pathways, based on the currently available research evidence for the purpose of providing new ideas for the prevention and treatment of digestive diseases.

Cell signaling and epigenetic regulation of nicotine-induced carcinogenesis

Nicotine, a naturally occurring tobacco alkaloid responsible for tobacco addiction, has long been considered non-carcinogenic. However, emerging evidence suggests that nicotine may possess carcinogenic properties in mice and could be a potential carcinogen in humans. This review aims to summarize the potential molecular mechanisms underlying nicotine-induced carcinogenesis, with a specific focus on epigenetic regulation and the activation of nicotinic acetylcholine receptors (nAChRs) in addition to genotoxicity and excess reactive oxygen species (ROS). Additionally, we explore a novel hypothesis regarding nicotine's carcinogenicity involving the downregulation of stem-loop binding protein (SLBP), a critical regulator of canonical histone mRNA, and the polyadenylation of canonical histone mRNA. By shedding light on these mechanisms, this review underscores the need for further research to elucidate the carcinogenic potential of nicotine and its implications for human health.

Research progress on the role of Ndfip1 (Nedd4 family interacting protein 1) in immune cells

Nedd4 family interacting protein 1 (Ndfip1) was first mentioned in an article in 2000. Since its discovery, related studies have shown that this protein is associated with apoptosis, neuroprotection, substance transport, ubiquitination, and immune regulation. It is noteworthy that the lack of Ndfip1 can lead to death in fetal mice. Researchers generally believe that the function of Ndfip1 is closely related to individual immune capacity and have published a large number of articles. However, a comprehensive classification of the immune regulatory function of Ndfip1 is still lacking. In this review, we will overview and discuss this new perspective, focusing on the role of Ndfip1 in the proliferation, differentiation, and cell activity of CD4⁺ T cells, CD8⁺ T cells, mast cells, and eosinophils. This review provides an updated summary of Ndfip1, which will unveil novel therapeutic targets. Finally, the conclusion is that Ndfip1 mainly plays a negative regulatory role in immune cells by maintaining the stability of the immune response and limiting its overexpression.

Unraveling the Potential Role of NEDD4-like E3 Ligases in Cancer

Cancer is a deadly disease worldwide, with an anticipated 19.3 million new cases and 10.0 million deaths occurring in 2020 according to GLOBOCAN 2020. It is well established that carcinogenesis and cancer development are strongly linked to genetic changes and post-translational modifications (PTMs). An important PTM process, ubiquitination, regulates every aspect of cellular activity, and the crucial enzymes in the ubiquitination process are E3 ubiquitin ligases (E3s) that affect substrate specificity and must therefore be carefully regulated. A surfeit of studies suggests that, among the E3 ubiquitin ligases, neuronal precursor cell-expressed developmentally downregulated 4 (NEDD4)/NEDD4-like E3 ligases show key functions in cellular processes by controlling subsequent protein degradation and substrate ubiquitination. In addition, it was demonstrated that NEDD4 mainly acts as an oncogene in various cancers, but also plays a tumor-suppressive role in some cancers. In this review, to comprehend the proper function of NEDD4 in cancer development, we summarize its function, both its tumor-suppressive and oncogenic role, in multiple types of malignancies. Moreover, we briefly explain the role of NEDD4 in carcinogenesis and progression, including cell survival, cell proliferation, autophagy, cell migration, invasion, metastasis, epithelial-mesenchymal transition (EMT), chemoresistance, and multiple signaling pathways. In addition, we briefly explain the significance of NEDD4 as a possible target for cancer treatment. Therefore, we conclude that targeting NEDD4 as a therapeutic method for treating human tumors could be a practical possibility.

WWP1 upregulation predicts poor prognosis and promotes tumor progression by regulating ubiquitination of NDFIP1 in intrahepatic cholangiocarcinoma

WW domain-containing E3 ubiquitin protein ligase1 (WWP1) is reported to be upregulated in many types of human cancers; however, its expression and function in intrahepatic cholangiocarcinoma (ICC) remain unknown. Here, in this study we investigated the expression pattern, clinical prognosis, tumor biological functions, and molecular mechanisms of WWP1 in ICC. The expression of WWP1 in patient tissues was detected by western blotting, immunohistochemistry (IHC), and immunofluorescence. CCK-8, colony formation, EdU, transwell, and xenograft models were used to explore the role of WWP1 in the proliferation and metastasis of ICC. Co-immunoprecipitation, mass spectrometry, chromatin immunoprecipitation, and immunofluorescence were performed to detect the potential mechanisms. Our study revealed that WWP1 was highly expressed in ICC, and high levels of WWP1 were associated with poor prognosis. Functionally, WWP1 overexpression enhanced the proliferation and metastasis of ICC cells and vice versa. Mechanistically, MYC could be enriched in the promoter region of WWP1 to facilitate its expression. Then, WWP1 targets Nedd4 family interacting protein1 (NDFIP1) and reduces NDFIP1 protein levels via ubiquitination. Downregulation of NDFIP1 in ICC cells rescued the effects of silenced WWP1 expression. WWP1 expression was also negatively correlated with the protein level of NDFIP1 in patient tissues. In conclusion, WWP1 upregulated by MYC promotes the progression of ICC via ubiquitination of NDFIP1, which reveals that WWP1 might be a potential therapeutic target for ICC.

Nicotine facilitates pancreatic fibrosis by promoting activation of pancreatic stellate cells via α7nAChR-mediated JAK2/STAT3 signaling pathway in rats

AIM

Smoking has been considered as a risk factor of chronic pancreatitis (CP), but the potential mechanism is still unknown. The major pathological feature of CP is pancreatic fibrosis, whose major functional cells are pancreatic stellate cells (PSCs). Nicotine is the major component of cigarette smoke, our recent study suggested that nicotine has the potential to facilitate pancreatic fibrosis in CP. This study was aimed to analyze the function and mechanism of nicotine on PSCs and pancreatic fibrosis in rats.

MATERIALS AND METHODS

In vivo, a rat CP model was induced by intraperitoneal injection of 20 % L-arginine hydrochloride (200 mg/100 g) at 1 h intervals twice per week, nicotine was injected subcutaneously at a dose of 1 mg/kg body weight per day. After four weeks, the pancreatic tissue was collected for H&E, Masson and immunohistochemical staining. In vitro, primary rPSCs were isolated from rats and treated with nicotine (0.1 μM and 1 μM). The proliferation、apoptosis、α-SMA expression、extracellular matrix (ECM) metabolism and α7nAChR-mediated JAK2/STAT3 signaling pathway of rPSCs were detected by CCK-8 assay、flow cytometry、real-time Q-PCR and western blotting analysis. The α7nAChR antagonist α-bungarotoxin (α-BTX) was used to perform inhibition experiments.

KEY FINDINGS

Nicotine increased pancreatic damage, collagen deposition and activation of PSCs in the CP rat model. In rPSCs, the proliferation, α-SMA expression and ECM formation were significantly promoted by nicotine in a dose-dependent manner. Meanwhile, the apoptosis of rPSCs was significantly reduced after nicotine treatment. Moreover, nicotine also activated the α7nAChR-mediated JAK2/STAT3 signaling pathway in rPSCs. These effects of nicotine on rPSCs were blocked by α-BTX.

SIGNIFICANCE

Our finding in this research suggests that nicotine facilitates pancreatic fibrosis by promoting activation of pancreatic stellate cells via α7nAChR-mediated JAK2/STAT3 signaling pathway in rats, partly revealing the mechanism of smoking on chronic pancreatitis.

Molecular mechanism involved in epithelial to mesenchymal transition

Epithelial to mesenchymal transition (EMT) is a biological process that plays an important role during embryonic development. During this process, the epithelial cells lose their polarity and acquire mesenchymal properties. In addition to embryonic development, EMT is also well-known to participate in tissue repair, inflammation, fibrosis, and tumor metastasis. In the present review, we address the basics of epithelial to mesenchymal transition during both development and disease conditions and emphasize the role of various transcription factors and miRNAs involved in the process.

A nicotine-induced positive feedback loop between HIF1A and YAP1 contributes to epithelial-to-mesenchymal transition in pancreatic ductal adenocarcinoma

BACKGROUND

Nicotine, an active ingredient in tobacco, can promote epithelial-to-mesenchymal transition (EMT) processes that enhance the aggressiveness of a number of human cancers. In the present study, we investigated whether cigarette smoke/nicotine drives EMT in pancreatic ductal adenocarcinoma (PDAC).

METHODS

Quantitative real-time PCR, western blot, immunohistochemistry, and immunofluorescence assays were used to evaluate Yes-associated protein 1 (YAP1) expression associated with cigarette smoking in human PDAC tissue samples and with nicotine exposure in PDAC cell lines. Bioinformatics, loss- and gain- of- function experiments, luciferase reporter assays, chromatin immunoprecipitation (ChIP), and murine tumor xenograft models were performed to examine the function of YAP1 in PDAC and to identify potential mechanisms of action.

RESULTS

Exposure to smoking or nicotine promoted EMT and tumor growth in PDAC cells and in xenograft tumors. Functional studies revealed that YAP1 might drive nicotine-stimulated EMT and oncogenic activity in vitro and in vivo. In human PDAC tissues, upregulation of YAP1 was associated with "ever smoking" status and poor overall survival. In term of mechanism, hypoxia inducible factor (HIF)1A promoted YAP1 nuclear localization and YAP1 transactivation by directly binding to the hypoxia responsive elements of the YAP1 promoter upon nicotine treatment. Nicotine stimulated HIF1A and YAP1 expression by activating cholinergic receptor nicotinic alpha7 (CHRNA7). In addition, YAP1 increased and sustained the protein stability of HIF1A.

CONCLUSIONS

These data demonstrate that YAP1 enhances nicotine-stimulated EMT and tumor progression of PDAC through a HIF1A/YAP1 positive feedback loop. Developing inhibitors that specifically target YAP1 may provide a novel therapeutic approach to suppress PDAC growth, especially in PDAC patients who have a history of smoking.