Revealing the oncogenic role of elevated GNL3L expression in esophageal squamous cell carcinoma: insights into the STAT3 pathway.

Background: Esophageal squamous cell carcinoma (ESCC) patients carries a poor prognosis, with limited effective therapeutic targets. This study aimed to clarify the clinical significance of guanine nucleotide-binding protein like 3-like (GNL3L) protein expression in ESCC and its role in malignant progression. Methods: GNL3L expression and associated cancer-promoting pathways in ESCC were interrogated via bioinformatics analysis through use of The Cancer Genome Atlas (TCGA) database. Subsequent verification of GNL3L protein expression in ESCC, coupled with clinical data, was conducted through immunohistochemistry and followed by a comprehensive prognostic analysis. We further investigated potential signaling pathways facilitating ESCC progression, employing a combination of bioinformatics analysis and immunohistochemical (IHC) experiments. Results: Bioinformatics analysis unveiled a significant elevation in GNL3L expression, particularly in gastrointestinal tumors and ESCC. Immunohistochemistry confirmed elevated GNL3L expression in ESCC tissues. Regression analysis established a correlation between elevated GNL3L expression and advanced tumor node metastasis (TNM) stage, with high expression associated with poor prognosis in patients with ESCC. Our integrated approach of bioinformatics and IHC analysis indicated a potential role of the signal transducers and activators of transcription 3 (STAT3) signaling pathway in ESCC progression. Conclusions: High GNL3L expression significantly contributes to the malignant progression of ESCC. This study further elucidates the mechanisms driving ESCC progression and offers possible insights for more effective diagnosis and treatment strategies.

Secretoglobin 3A2 protects lung from developing cigarette smoke-induced pulmonary emphysema.

Secretoglobin (SCGB) 3A2 is a bioactive molecule exhibiting various functions such as improving allergic airway inflammation and pulmonary fibrosis and promoting bronchial branching and proliferation during lung development. To determine if and how SCGB3A2 is involved in chronic obstructive pulmonary disease (COPD), a multifactorial disease with both airway and emphysematous lesions, a COPD mouse model was created by exposing Scgb3a2-deficient (KO), Scgb3a2-lung-specific overexpressing (TG), and wild type (WT) mice to cigarette smoke (CS) for 6 months. The KO mice showed loss of lung structure under control condition, and CS exposure resulted in more expansion of airspace and destruction of alveolar wall than WT mouse lungs. In contrast, TG mouse lungs showed no significant changes after CS exposure. SCGB3A2 increased the expression and phosphorylation of signal transducers and activators of transcription (STAT)1 and STAT3, and the expression of α1-antitrypsin (A1AT) in mouse lung fibroblast-derived MLg cells and mouse lung epithelial-derived MLE-15 cells. In MLg cells, A1AT expression was decreased in Stat3-knockdown cells, and increased upon Stat3 overexpression. STAT3 formed a homodimer when cells were stimulated with SCGB3A2. Chromatin immunoprecipitation and reporter assays demonstrated that STAT3 binds to specific binding sites on the Serpina1a gene encoding A1AT and upregulates its transcription in lung tissues of mice. Furthermore, nuclear localization of phosphorylated STAT3 upon SCGB3A2 stimulation was detected by immunocytochemistry. These findings demonstrate that SCGB3A2 protects the lungs from the development of CS-induced emphysema by regulating A1AT expression through STAT3 signaling.

The research development of STAT3 in hepatic ischemia-reperfusion injury.

Ischemia-reperfusion injury (IRI) is a common complication of surgery, which can cause rapid deterioration of the liver function, increase the risk of graft rejection, and seriously affect the prognosis of patients. The signal transducer and activator of transcription 3 (STAT3) protein has been implicated in pathogenesis of IRI. STAT3 influences the mitochondria through multiple pathways and is also involved in apoptosis and other forms of programmed cell death. STAT3 is associated with Janus kinase (JAK), phosphoinositide-3 kinase (PI3K), and heme oxygenase-1 (HO-1) in liver IRI. The STAT3 pathway plays a dual role in IRI as it can also regulate lipid metabolism which may have potential for treating IRI fatty liver. In this review, we summarize research on the function of STAT3 in liver IRI to provide references for its application in the clinic.

Da Chaihutang Inhibits Hepatocellular Carcinoma by Regulating p38 MAPK/IL-6/STAT3 Signaling Pathway / 中国实验方剂学杂志

ObjectiveThis study aims to investigate the efficacy and underlying mechanism of Da Chaihutang （DCHT） in treating hepatocellular carcinoma （HCC） in vitro and in vivo. MethodWe employed methyl thiazolyl tetrazolium （MTT） assay and crystal violet staining to observe the proliferation of Hepa1-6 liver cancer cells treated with DCHT at different doses （0， 125， 250， 500， 1 000 mg·L-1） for different time periods （1， 2， 4， 8 days）. The orthotopic liver cancer model was established by injection of 1×106 Hepa1-6 cells into mouse， and then the model mice were randomly assigned into six groups： blank， model， DCHT （0.21， 0.625， 1.875 g·kg-1， ig， qd）， and positive control （5-fluorouracil， 25 mg·kg-1， ip， qod）. After 14 days of administration， the mice were sacrificed， and the liver samples were collected and fixed in 4% paraformaldehyde for hematoxylin-eosin （HE） staining. The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform （TCMSP）， Cytoscape 3.7.2， STRING， and DAVID were used for the searching of the key targets of DCHT in treating HCC， the construction of protein-protein interaction （PPI） network， and the Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment. Quantitative real-time PCR was performed to determine the mRNA level of interleukin-6 （IL-6） in Hepa1-6 cells and liver tissue. Western blotting was employed to measure the protein levels of the proteins involved in the mitogen-activated protein kinase （MAPK） and signal transducers and activators of transcription 3 （STAT3） signaling pathways. ResultDCHT （500， 1 000 mg·L-1） treatment for 4 and 8 days inhibited the proliferation of Hepa1-6 cells in a dose- and time-dependent manner （P<0.05）. The in vivo assay showed that DCHT （high dose， 1.875 g·kg-1） treatment for 14 days led to high differentiation and unobvious heterogeneity of HCC cells and small necrotic area compared with the model group. Network pharmacology analysis predicted that the potential targets of DCHT in the treatment of HCC were mainly the inflammation cytokines such as IL-6， interleukin-1β （IL-1β）， and tumor necrosis factor-alpha （TNF-α） in HCC microenvironment. The potential signaling pathways involved in the treatment were mainly associated with HCC growth and differentiation， including MAPK and STAT3 signaling pathways. Compared with the blank group， DCHT （1 000 mg·L-1） treatment for 1， 2， 4， and 8 days down-regulated the mRNA level of IL-6 in Hepa1-6 cells （P<0.05）. Similar results were observed in the livers of mice treated with DCHT （0.625， 1.875 g·kg-1）. The in vitro assay demonstrated that DCHT （1 000 mg·L-1） treatment for 4 and 8 days and DCHT （500， 1 000 mg·L-1） treatment inhibited the phosphorylation of extracellular signal-regulated kinases 1/2 （ERK1/2）， c-Jun NH2-terminal kinase/stress-activated protein kinase （JNK）， p38 MAPK， and STAT3 in a dose- and time-dependent manner （P<0.05）. The in vivo assay showed that DCHT （0.625 and 1.875 g·kg-1） treatment only inhibited the phosphorylation of p38 MAPK and STAT3 （P<0.05）. ConclusionThe present study indicates that DCHT can inhibit liver cancer cell proliferation by regulating p38 MAPK/IL-6/STAT3 signaling pathway.

Regulatory Mechanism and Role of STAT3 Signaling Pathway in Multiple Myeloma / 中国生物化学与分子生物学报

Multiple myeloma (MM) is a kind of plasma cell tumor, characterized by clonal expansion of malignant plasma cells in the micro-environment of bone marrow, production of monoclonal immunoglobulins and dysfunction of related organs. In recent years, with the introduction of autologous stem cell transplantation and the application of Lenalidomide and Bortezomib, the traditional treatment of myeloma had been changed and the overall survival of the patients was prolonged. Although significant progresses have been made in treatment, multiple myeloma is still incurable, mainly due to primary drug resistance and disease recurrence. Signal transducers and activators of transcription 3 (STAT3) is a kind of signal transcription factor, which is involved in diverse cellular processes including the differentiation, proliferation and angiogenesis in normal cells. Recently, it had been found that the high expression of STAT3 in tumors was closely related to the occurrence, development, invasion and metastasis of malignant tumors. STAT3 also played a key role in the occurrence and progression of multiple myeloma. In this paper, we reviewed the molecular structure, signal pathway, activation, regulation and basic biological functions of STAT3, and found that non coding RNA, heat shock protein 90 (Hsp90), heme oxygenase-1 (HO-1) and other factors play important roles in the occurrence, survival and immune escape of multiple myeloma through STAT3 pathway whose activation is related to the resistance of multiple myeloma cells to Bortezomib, Lenalidomide and other conventional drugs. Therefore, STAT3 can be used as a potential target for multiple myeloma. This review provides a basis for accurate diagnosis and treatment of MM and a reference for STAT3 as a potential prognostic marker.

Effect of Shenling Baizhusan on mTORC1/STAT3 Pathway in Hepatocytes of Nonalcoholic Fatty Liver Disease Rats / 中国实验方剂学杂志

Objective::To observe the effect of Shenling Baizhusan(SBS)on the mammalian target of rapamycin complex 1 (mTORC1)/signal transducers and activators of transcription 3 (STAT3) pathway in liver hepatocyte of nonalcoholic fatty liver disease(NAFLD)rats induced by high fat diet, in order to reveal the mechanism of SBS against rat NAFLD from the perspective of inflammation. Method::Totally 80 SD rats were randomly divided into 4 groups, normal control group, model group, high-dose SBP group(30 g·kg-1), and low-dose SBS group(10 g·kg-1), with 20 rats in each group. The rats of NAFLD model were established by being fed with high-fat diets for 8 weeks, and the treatment groups were fed with high or low dose of SBS respectively. After treatment for 8 weeks, blood and liver samples of rats were collected. Alanine aminotransferase (ALT), aspartate aminotransferase(AST), total cholesterol (TC), triglyceride(TG), high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)levels in blood serum were detected with automatic biochemical analyzer. The liver tissues were observed by oil red O and hematoxylin-eosin (HE) staining. Hepatocytes were isolated by type Ⅳ collagenase perfusion in vitro. Tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-5 and IL-6 in hepatocytes were detected by enzyme-linked immunosorbent assay (ELISA), and the relevant gene and proteins expressions of mTORC1 and STAT3 in hepatocytes were detected by Real-time fluorescent quantitative polymerase chain reaction (Real-time PCR) and Western blot detection respectively. Result::Compared with the normal control group, the serum levels of TG, TC, AST, ALT and LDL-C were increased significantly, the levels of TNF-α, IL-1β, IL-5 and IL-6 in hepatocytes were increased significantly, and the expression levels of mTORC1, STAT3 mRNA and proteins in hepatocytes were increased significantly(P<0.01). Compared with the model group, the hepatic lipid accumulation of the medicine intervention group was relieved significantly, the serum levels of AST, ALT, TG and LDL-C were decreased significantly, the expression levels of TNF-α, IL-1β, IL-5 and IL-6 of hepatocytes were decreased significantly, and the expressions of mTORC1, STAT3 mRNA and proteins in hepatocytes were decreased significantly(P<0.05, P<0.01). In the high-dose SBS group, the effects in improving the lipid accumulation and inhibiting the inflammatory reaction were better than those of the low-dose SBS group, and the expressions of mTORC1 and STAT3 genes and proteins in hepatocytes were significantly decreased (P<0.05, P<0.01). Conclusion::SBS can improve the fat metabolism disorder and reduce liver lipid accumulation and inflammatory reaction in NAFLD rats induced by high-fat diet. The mechanism may be correlated with the inhibition of mTORC1/STAT3 pathway relating to genes and protein expression in hepatocytes.

Stat3 in osteocytes mediates osteogenic response to loading.

Signal transducer and activator of transcription 3 (Stat3) is a member of the Stat family of proteins involved in signaling in many different cell types, including osteocytes. Osteocytes are considered major mechanosensing cells in bone due to their intricate dendritic networks able to sense changes in physical force and to orchestrate the response of osteoclasts and osteoblasts. We examined the role of Stat3 in osteocytes by generating mice lacking Stat3 in these cells using the Dmp-1(8kb)-Cre promoter (Stat3cKO mice). Compared to age-matched littermate controls, Stat3cKO mice of either sex (18 weeks old) exhibit reduced bone formation indices, decreased osteoblasts and increased osteoclasts, and altered material properties, without detectable changes in bone mineral density (BMD) or content of either trabecular or cortical bone. In addition, Stat3cKO mice of either sex show significantly decreased load-induced bone formation. Furthermore, pharmacologic inhibition of Stat3 in osteocytes in vitro with WP1066 blocked the increase in cytosolic calcium induced by ATP, a mediator of the cellular responses to sheer stress. WP1066 also increased reactive oxygen species (ROS) production in cultured MLO-Y4 osteocytes. These data demonstrate that Stat3 is a critical mediator of mechanical signals received by osteocytes and suggest that osteocytic Stat3 is a potential therapeutic target to stimulate bone anabolism.

PP-22 promotes autophagy and apoptosis in the nasopharyngeal carcinoma cell line CNE-2 by inducing endoplasmic reticulum stress, downregulating STAT3 signaling, and modulating the MAPK pathway.

Paris polyphylla var. yunnanensis, named Chong Lou, is considered an antitumor substance. In this study, we investigated the effect of PP-22, a monomer purified from P. polyphylla var. yunnanensis, on the nasopharyngeal carcinoma cell line CNE-2 in vitro. The results showed that PP-22 could inhibit the proliferation of CNE-2 cells via the induction of apoptosis, with evidence of the characteristic morphological changes in the apoptosis in the nucleus and an increase in Annexin V-positive cells. In addition, we found that PP-22 could activate the p38 mitogen-activated protein kinase (MAPK) pathway and that this activation was reversed by SB203580, a specific inhibitor of the p38 MAPK pathway. In contrast, PP-22 promoted apoptosis via an intrinsic pathway, including the endoplasmic reticulum stress pathway, in a caspase-dependent manner. A further study showed that PP-22 also induced apoptosis by downregulating the signal transducers and activators of transcription 3 (STAT3) pathway, and the inhibitory effect was also confirmed by STAT3 small interfering RNA. In addition, PP-22 could promote autophagy by inhibiting the extracellular regulated protein kinases (ERK) pathway. And autophagy plays a protective role against apoptosis. Together, these data show that PP-22 promotes autophagy and apoptosis in the nasopharyngeal carcinoma CNE-2 cell line.