The role of p-Stat3 Y705 immunohistochemistry in glioblastoma prognosis

STAT3 activation of SCAP-SREBP-1 signaling upregulates fatty acid synthesis to promote tumor growth

SCAP plays a central role in controlling lipid homeostasis by activating SREBP-1, a master transcription factor in controlling fatty acid (FA) synthesis. However, how SCAP expression is regulated in human cancer cells remains unknown. Here, we revealed that STAT3 binds to the promoter of SCAP to activate its expression across multiple cancer cell types. Moreover, we identified that STAT3 also concurrently interacts with the promoter of SREBF1 gene (encoding SREBP-1), amplifying its expression. This dual action by STAT3 collaboratively heightens FA synthesis. Pharmacological inhibition of STAT3 significantly reduces the levels of unsaturated FAs and phospholipids bearing unsaturated FA chains by reducing the SCAP-SREBP-1 signaling axis and its downstream effector SCD1. Examination of clinical samples from patients with glioblastoma, the most lethal brain tumor, demonstrates a substantial co-expression of STAT3, SCAP, SREBP-1, and SCD1. These findings unveil STAT3 directly regulates the expression of SCAP and SREBP-1 to promote FA synthesis, ultimately fueling tumor progression.

Signal Transducer and Activator of Transcription Proteins at the Nexus of Immunodeficiency, Autoimmunity and Cancer

The signal transducer and activator of transcription (STAT) family of proteins has been demonstrated to perform pivotal roles downstream of a myriad of cytokines, particularly those that control immune cell production and function. This is highlighted by both gain-of-function (GOF) and loss-of-function (LOF) mutations being implicated in various diseases impacting cells of the immune system. These mutations are typically inherited, although somatic GOF mutations are commonly observed in certain immune cell malignancies. This review details the growing appreciation of STAT proteins as a key node linking immunodeficiency, autoimmunity and cancer.

Expression and association of vascular endothelial growth factor, vascular endothelial growth factor receptor, and phosphorylated signal transducer and activator of transcription factor 3 in malignant gliomas

Objectives

Angiogenesis is one of the main characteristic features of malignant gliomas. Phosphorylated signal transducer and activator of transcription factor 3 (pSTAT3) is not only involved in glioma cell proliferation, anti-apoptosis, and immunosuppression but also plays a key role in cell migration and invasion. Constitutively, activated pSTAT3 induces expression of vascular endothelial growth factor (VEGF) and its receptor VEGFR, leading to endothelial cell proliferation and abnormal microvascular formation causing peritumoral edema (PTE). PTE is one of the significant contributors to mortality in malignant gliomas. Therefore, understanding the molecular mechanism involved in the evolution of gliomas is necessary. This study was to assess the level of expression of pSTAT3, VEGF, and VEGFR in malignant gliomas and analyze the extent of PTE and the extent of expression of one or more of these markers.

Materials and Methods

This study included 84 patients categorized as per the World Health Organization classification of central nervous system tumors into grade IV, III, and II gliomas to investigate the expression of pSTAT3, VEGF, and VEGFR by immunohistochemistry. Furthermore, the presence or absence of PTE was determined using magnetic resonance imaging/computed tomography scans in these patients.

Results

The association between the markers (pSTAT3, VEGFR, and VEGF) and the extent of PTE in these patients was statistically significant (P < 0.05).

Conclusion

The pSTAT3, VEGF-R, and VEGF signaling pathways could contribute to peritumoral edema and might be a regulatory mechanism during PTE formation during tumorigenesis and progression.

Inhibition of STAT3 signaling as critical molecular event in HUC-MSCs suppressed Glioblastoma Cells

Objective: We investigated the effect of human umbilical cord mesenchymal stem cells (HUC-MSCs) supernatants on proliferation, migration, invasion, and apoptosis in glioblastoma (GBM) cell lines RG-2, U251, U87-MG, and LN-428, as well as their apoptosis and autophagy-mediated through IL-6/JAK2/STAT3 signaling pathway to explore the molecular mechanisms. Methods: In this study, RG-2, U251, U87-MG, and LN-428 cells were treated with 9 mg/ml HUC-MSCs supernatants. Their responses to HUC-MSCs supernatants treatment and the status of STAT3 signaling were analyzed by multiple experimental approaches to elucidate the importance of HUC-MSCs supernatants for GBM. Results: The results demonstrated that after treatment with HUC-MSCs supernatants, in vitro proliferation of RG-2, U251, U87-MG, and LN-428 cells were inhibited, and their sustained growth was also blocked. RG-2, U251, and U87-MG cells showed significant S phase accumulation, while LN-428 cells were blocked in G0/G1 phase. Their migratory invasive capacities were inhibited, and their apoptosis and autophagy ratios were increased. These effects were mediated through the IL-6/JAK2/STAT3 and its downstream signaling pathway. Conclusion: Our data showed that HUC-MSCs supernatants had anti-tumor effects on GBM cells. It inhibited the proliferation, migration, and invasion of GBM cells and promoted their apoptosis. Negative regulation of the IL-6/JAK2/STAT3 signaling pathway enhanced apoptosis and autophagy in tumor cells, thereby improving the therapeutic effect on GBM.

Loss of cell-cell adhesion triggers cell migration through Rac1-dependent ROS generation

Epithelial cells usually trigger their "migratory machinery" upon loss of adhesion to their neighbors. This default is important for both physiological (e.g., wound healing) and pathological (e.g., tumor metastasis) processes. However, the underlying mechanism for such a default remains unclear. In this study, we used the human head and neck squamous cell carcinoma (HNSCC) SAS cells as a model and found that loss of cell-cell adhesion induced reactive oxygen species (ROS) generation and vimentin expression, both of which were required for SAS cell migration upon loss of cell-cell adhesion. We demonstrated that Tiam1-mediated Rac1 activation was responsible for the ROS generation through NADPH-dependent oxidases. Moreover, the ROS-Src-STAT3 signaling pathway that led to vimentin expression was important for SAS cell migration. The activation of ROS, Src, and STAT3 was also detected in tumor biopsies from HNSCC patients. Notably, activated STAT3 was more abundant at the tumor invasive front and correlated with metastatic progression of HNSCC. Together, our results unveil a mechanism of how cells trigger their migration upon loss of cell-cell adhesion and highlight an important role of the ROS-Src-STAT3 signaling pathway in the progression of HNSCC.

The Implications of Noncoding RNAs in the Evolution and Progression of Nonalcoholic Fatty Liver Disease (NAFLD)-Related HCC

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver pathology worldwide. Meanwhile, liver cancer represents the sixth most common malignancy, with hepatocellular carcinoma (HCC) as the primary, most prevalent subtype. Due to the rising incidence of metabolic disorders, NAFLD has become one of the main contributing factors to HCC development. However, although NAFLD might account for about a fourth of HCC cases, there is currently a significant gap in HCC surveillance protocols regarding noncirrhotic NAFLD patients, so the majority of NAFLD-related HCC cases were diagnosed in late stages when survival chances are minimal. However, in the past decade, the focus in cancer genomics has shifted towards the noncoding part of the genome, especially on the microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), which have proved to be involved in the regulation of several malignant processes. This review aims to summarize the current knowledge regarding some of the main dysregulated, noncoding RNAs (ncRNAs) and their implications for NAFLD and HCC development. A central focus of the review is on miRNA and lncRNAs that can influence the progression of NAFLD towards HCC and how they can be used as potential screening tools and future therapeutic targets.

Ferroptosis Involvement in Glioblastoma Treatment

Glioblastoma multiforme (GBM) is one of the deadliest brain tumors. Current standard therapy includes tumor resection surgery followed by radiotherapy and chemotherapy. Due to the tumors invasive nature, recurrences are almost a certainty, giving the patients after diagnosis only a 12–15 months average survival time. Therefore, there is a dire need of finding new therapies that could potentially improve patient outcomes. Ferroptosis is a newly described form of cell death with several implications in cancer, among which GBM. Agents that target different molecules involved in ferroptosis and that stimulate this process have been described as potentially adjuvant anti-cancer treatment options. In GBM, ferroptosis stimulation inhibits tumor growth, improves patient survival, and increases the efficacy of radiation and chemotherapy. This review provides an overview of the current knowledge regarding ferroptosis modulation in GBM.

ELK3: A New Molecular Marker for the Diagnosis and Prognosis of Glioma

ETS transcription factor ELK3 (ELK3), a novel oncogene, affects pathological processes and progression of many cancers in human tissues. However, it remains unclear whether ELK3, as a key gene, affects the pathological process of gliomas and the prognosis of patients with gliomas. This study aimed to comprehensively and systematically reveal the correlation between ELK3 and the malignant progression of gliomas by analyzing clinical sample information stored in multiple databases. We revealed the putative mechanism of ELK3 involvement in malignant gliomas progression and identified a new and efficient biomarker for glioma diagnosis and targeted therapy. Based on the sample data from multiple databases and real-time quantitative polymerase chain reaction (RT-qPCR), the abnormally high expression of ELK3 in gliomas was confirmed. Kaplan-Meier and Cox regression analyses demonstrated that a high ELK3 expression was markedly associated with low patient survival and served as an independent biomarker of gliomas. Wilcox and Kruskal-Wallis tests revealed that expression of ELK3 was positively correlated with several clinical characteristics of patients with gliomas, such as age, WHO classification, and recurrence. Moreover, Cell Counting Kit‐8 (CCK-8), immunofluorescence, and wound healing assays confirmed that ELK3 overexpression markedly promoted the proliferation and migration of glioma cells. Finally, gene set enrichment analysis (GSEA) and western blotting confirmed that overexpression of ELK3 regulated the JAK–STAT signaling pathway and upregulate the expression of signal transducer and activator of transcription 3 (STAT3) and phosphorylated STAT3 (P-STAT3) to promote the malignant transition of gliomas. Therefore, ELK3 may serve as an efficient biomarker for the diagnosis and prognosis of gliomas and it can also be used as a therapeutic target to improve the poor prognosis of patients with gliomas.

Clinicopathological and Prognostic Roles of STAT3 and Its Phosphorylation in Glioma

Glioma is defined as a common brain tumor which causes severe disability or death. As many genes are reported to relate with glioma's occurrence and development, their prognostic and therapeutic value still remains uncertain. This study aimed at investigating the association between STAT3/p-STAT3 and glioma prognosis. Nine studies (12 trials) scored ≥5 on the Newcastle-Ottawa scale were meta-analysed from the Medline, Embase, and Web of Science databases. We found that STAT3/p-STAT3 overexpression in glioma patients was associated with worse overall survival (hazard  ratio  (HR) = 1.40, 95%confidence  interval  (CI) = 1.05 ~ 1.86, P = 0.020), progression-free survival (HR = 2.05, 95%CI = 1.63 ~ 2.58, P < 0.001), and better recurrence-free survival (HR = 0.37, 95%CI = 0.15 ~ 0.95, P < 0.039). Subgroup analysis implied that STAT3/p-STAT3 overexpression was associated with worse OS in standard treatment (HR = 1.80, 95%CI = 1.06 ~ 3.04, P = 0.030), and in China (HR = 2.18, 95%CI = 1.77 ~ 2.70, P < 0.001), and metaregression analysis indicated countries (P = 0.001) may be the source of heterogeneity in our study. In conclusion, we suggested STAT3/p-STAT3 was associated with poor prognosis in patients with glioma, which indicated that STAT3/p-STAT3 might be a valuable prognostic biomarker and a promising therapeutic target for glioma.

Global quantitative phosphoproteome reveals phosphorylation network of bovine lung tissue altered by Mycobacterium bovis

Bovine tuberculosis caused by Mycobacterium bovis remains a major cause of economic loss in cattle industries worldwide. However, the pathogenic mechanisms remain poorly understood. Post-translation modifications (PTM) such as phosphorylation play a crucial role in pathogenesis. While the change of transcriptome and proteome during the interaction between M. bovis and cattle were studied, there are no reports on the phosphoproteome change. We apply Tandem Mass Tag-based (TMT) quantitative proteomics coupled with immobilized metal-chelated affinity chromatography (IMAC) enrichment to obtain the quantified phosphorylation in vivo of M. bovis infected cattle lung tissue. The phosphorylated proteins are widespread in the nucleus, cytoplasm and plasma membrane. By using a change fold of 1.2, 165 phosphosites from 147 proteins were enriched, with 88 upregulated and 77 downregulated sites respectively. We further constructed the protein-protein interaction (PPI) networks of STAT3, SRRM2 and IRS-1 based on their number of differential phosphorylation sites and KEGG pathways. Similar patterns of gene expression dynamics of selected genes were observed in Mycobacterium tuberculosis infected human sample GEO dataset, implicating crucial roles of these genes in pathogenic Mycobacteria - host interaction. The first phosphorproteome reveals the relationship between bovine tuberculosis and glucose metabolism, and will help further refinement of target proteins for mechanistic study.