Structural Constraint of Osteopontin Facilitates Efficient Binding to CD44

Combined proteomics and metabolomics analysis reveal the effect of a training course on the immune function of Chinese elite short-track speed skaters

INTRODUCTION

The aim of this study was to combine proteomics and metabolomics to evaluate the immune system of short-track speed skaters (STSS) before and after a training course. Our research focused on changes in urinary proteins and metabolites that have the potential to serve as indicators for training load.

METHODS

Urine samples were collected from 21 elite STSS (13 male and 8 female) of the China National Team before and immediately after one training course. First-beat sports sensor was used to monitor the training load. Proteomic detection was performed using a Thermo UltiMate 3000 ultra high performence chromatography nano liquid chromatograph and an Orbitrap Exploris 480 mass spectrometer. MSstats (R package) was used for the statistical evaluation of significant differences in proteins from the samples. Two filtration criteria (fold change [FC] > 2 and p < 0.05) were used to identify the differential expressed proteins. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis for differential proteins was performed to identify the pathways involved. Nontargeted metabolomic detection was performed using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS_) with an ACQUITY 2D UPLC plus Q Exactive (QE) hybrid Quadrupole-Orbitrap mass spectrometer. Differential metabolites were identified using non-parametric statistical methods (Wilcox's rank test). Two filtration criteria (FC > 1.2 and p < 0.05) were used to identify differential metabolites. Combined analysis of proteomic and metabolomics were performed on the "Wu Kong" platform. Correlation analysis was performed using Spearman's rank correlation coefficient.

RESULTS

(1) The most upregulated proteins were immune-related proteins, including complement proteins (C9, C4-B, and C9) and immunoglobulins (IgA, IgM, and IgG). The most downregulated proteins were osteopontin (OPN) and CD44 in urine. The correlation analysis showed that the content of OPN and CD44 (the receptor for OPN) in urine were significantly negatively correlated with the upregulated immune-related proteins. The content of OPN and CD44 is sex-dependent and negatively correlated with the training load. (2) The most upregulated metabolites included lactate, cortisol, inosine, glutamine, argininosuccinate (the precursor for arginine synthesis), 3-methyl-2-oxobutyrate (the catabolite of valine), 3-methyl-2-oxovalerate (the catabolite of isoleucine), and 4-methyl-2-oxopentanoate (the catabolite of leucine), which is sex-dependent and negatively correlated with OPN and CD44. (3) The joint analysis revealed five main related pathways, including the immune and innate immune systems. The enriched immune-related proteins included complements, immunoglobulins, and protein catabolism-related proteins. The enriched immune-related metabolites included cAMP, N-acetylgalactosamine, and glutamate. (4) There is a significant negative correlation between the content of OPN and CD44 in urine and the training load.

CONCLUSION

One training course can lead to the activation of the immune system and a sex-dependent decrease in the content of OPN and CD44. Training load has a significant and negative correlation with the content of OPN and CD44, suggesting that OPN and CD44 could be potential indicators for training load.

Osteopontin: A Key Multifaceted Regulator in Tumor Progression and Immunomodulation

The tumor microenvironment (TME) is composed of various cellular components such as tumor cells, stromal cells including fibroblasts, adipocytes, mast cells, lymphatic vascular cells and infiltrating immune cells, macrophages, dendritic cells and lymphocytes. The intricate interplay between these cells influences tumor growth, metastasis and therapy failure. Significant advancements in breast cancer therapy have resulted in a substantial decrease in mortality. However, existing cancer treatments frequently result in toxicity and nonspecific side effects. Therefore, improving targeted drug delivery and increasing the efficacy of drugs is crucial for enhancing treatment outcome and reducing the burden of toxicity. In this review, we have provided an overview of how tumor and stroma-derived osteopontin (OPN) plays a key role in regulating the oncogenic potential of various cancers including breast. Next, we dissected the signaling network by which OPN regulates tumor progression through interaction with selective integrins and CD44 receptors. This review addresses the latest advancements in the roles of splice variants of OPN in cancer progression and OPN-mediated tumor-stromal interaction, EMT, CSC enhancement, immunomodulation, metastasis, chemoresistance and metabolic reprogramming, and further suggests that OPN might be a potential therapeutic target and prognostic biomarker for the evolving landscape of cancer management.

CD44: a cancer stem cell marker and therapeutic target in leukemia treatment

CD44 is a ubiquitous leukocyte adhesion molecule involved in cell-cell interaction, cell adhesion, migration, homing and differentiation. CD44 can mediate the interaction between leukemic stem cells and the surrounding extracellular matrix, thereby inducing a cascade of signaling pathways to regulate their various behaviors. In this review, we focus on the impact of CD44s/CD44v as biomarkers in leukemia development and discuss the current research and prospects for CD44-related interventions in clinical application.

Osteopontin induces mitochondrial biogenesis in deadherent cancer cells

Metastasizing cells display a unique metabolism, which is very different from the Warburg effect that arises in primary tumors. Over short time frames, oxidative phosphorylation and ATP generation are prominent. Over longer time frames, mitochondrial biogenesis becomes a pronounced feature and aids metastatic success. It has not been known whether or how these two phenomena are connected. We hypothesized that Osteopontin splice variants, which synergize to increase ATP levels in deadherent cells, also increase the mitochondrial mass via the same signaling mechanisms. Here, we report that autocrine Osteopontin does indeed stimulate an increase in mitochondrial size, with the splice variant -c being more effective than the full-length form -a. Osteopontin-c achieves this via its receptor CD44v, jointly with the upregulation and co-ligation of the chloride-dependent cystine-glutamate transporter SLC7A11. The signaling proceeds through activation of the known mitochondrial biogenesis inducer PGC-1 (which acts as a transcription coactivator). Peroxide is an important intermediate in this cascade, but surprisingly acts upstream of PGC-1 and is likely produced as a consequence of SLC7A11 recruitment and activation. In vivo, suppression of the biogenesis-inducing mechanisms leads to a reduction in disseminated tumor mass. This study confirms a functional connection between the short-term oxidative metabolism and the longer-term mitochondrial biogenesis in cancer metastasis - both are induced by Osteopontin-c. The results imply possible mechanisms and targets for treating cancer metastasis.

Regulatory roles of Osteopontin in lung epithelial inflammation and epithelial-telocyte interaction

BACKGROUND

Lung epithelial cells play important roles in lung inflammation and injury, although mechanisms remain unclear. Osteopontin (OPN) has essential roles in epithelial damage and repair and in lung cancer biological behaviours. Telocyte (TC) is a type of interstitial cell that interacts with epithelial cells to alleviate acute inflammation and lung injury. The present studies aim at exploring potential mechanisms by which OPN regulates the epithelial origin lung inflammation and the interaction of epithelial cells with TCs in acute and chronic lung injury.

METHODS

The lung disease specificity of OPN and epithelial inflammation were defined by bioinformatics. We evaluated the regulatory roles of OPN in OPN-knockdown or over-expressed bronchial epithelia (HBEs) challenged with cigarette smoke extracts (CSE) or in animals with genome OPN knockout (gKO) or lung conditional OPN knockout (cKO). Acute lung injury and chronic obstructive pulmonary disease (COPD) were induced by smoking or lipopolysaccharide (LPS). Effects of OPN on PI3K subunits and ERK were assessed using the inhibitors. Spatialization and distribution of OPN, OPN-positive epithelial subtypes, and TCs were defined by spatial transcriptomics. The interaction between HBEs and TCs was assayed by the co-culture system.

RESULTS

Levels of OPN expression increased in smokers, smokers with COPD, and smokers with COPD and lung cancer, as compared with healthy nonsmokers. LPS and/or CSE induced over-production of cytokines from HBEs, dependent upon the dysfunction of OPN. The severity of lung inflammation and injury was significantly lower in OPN-gKO or OPN-cKO mice. HBEs transferred with OPN enhanced the expression of phosphoinositide 3-kinase (PI3K)CA/p110α, PIK3CB/p110β, PIK3CD/p110δ, PIK3CG/p110γ, PIK3R1, PIK3R2 or PIK3R3. Spatial locations of OPN and OPN-positive epithelial subtypes showed the tight contact of airway epithelia and TCs. Epithelial OPN regulated the epithelial communication with TCs, and the down-regulation of OPN induced more alterations in transcriptomic profiles than the up-regulation.

CONCLUSION

Our data evidenced that OPN regulated lung epithelial inflammation, injury, and cell communication between epithelium and TCs in acute and chronic lung injury. The conditional control of lung epithelial OPN may be an alternative for preventing and treating epithelial-origin lung inflammation and injury.

Exploring potential targets of Actinidia chinensis Planch root against hepatocellular carcinoma based on network pharmacology and molecular docking and development and verification of immune-associated prognosis features for hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the malignant tumors with the highest morbidity and mortality worldwide, and its prognosis remains a challenge. Actinidia chinensis Planch (ACP) root has good efficacy against HCC. This study aimed to explore the link between ACP and potential targets of HCC, and to develop a novel immune-based gene signature to predict HCC patient survival.

Methods

Transcriptome data and clinical information on HCC were obtained from The Cancer Genome Atlas (TCGA; HCC: 374, normal: 50) and International Cancer Genome Consortium (ICGC) database (HCC: 243, normal: 202). Combined with the 2,483 immune-related genes from the Immport database, we used the least absolute shrinkage and selection operator (LASSO) to construct a prognostic model. Patients were divided into high-risk and low-risk groups by the median of the risk scores of the TCGA cohort. Kaplan-Meier survival analysis and receiver operating characteristic (ROC) curves were used to estimate the predictability of the model in HCC prognosis, and carried out external validation based on ICGC cohort. We analyzed the correlation of this model with immune cells and immune checkpoint genes. Finally, molecular docking of these genes and the corresponding ACP components.

Results

We constructed a prognostic model composed of 3 immune-related genes [epidermal growth factor (EGF), baculoviral inhibitor of apoptosis repeat-containing protein 5 (BIRC5), and secreted phosphoprotein 1 (SPP1)]. And the high-risk group had a lower overall survival (OS) rate compared to the low-risk group (TCGA cohort: P=1.761e-05, ICGC cohort: P=8.716e-04). The outcomes of the AUC of ROC of prognostic risk model to predict for 1-, 2-, and 3-year OS: TCGA cohort: 0.749, 0.710, and 0.653 and ICGC cohort: 0.698, 0.736, and 0.753. Molecular docking results showed that quercetin had good binding activities with SPP1, BIRC5, and EGF, and ursolic acid (UA) and BIRC5 also had this feature.

Conclusions

Our study speculates that ACP root anti-HCC may be involved in the immune regulation of the body by targeting EGF, BIRC5 and SPP1, which possess great potential and value as early warning molecules for HCC. This model may provide a reference for individualized diagnosis and treatment for HCC patients.