The significance of Stanniocalcin 2 in malignancies and mechanisms

The IGF-PAPP-A-Stanniocalcin Axis in Serum and Ascites Associates with Prognosis in Patients with Ovarian Cancer

Pregnancy-associated plasma protein-A (PAPP-A) and PAPP-A2 modulate insulin-like growth factor (IGF) action and are inhibited by the stanniocalcins (STC1 and STC2). We previously demonstrated increased PAPP-A and IGF activity in ascites from women with ovarian carcinomas. In this prospective, longitudinal study of 107 women with ovarian cancer and ascites accumulation, we determined corresponding serum and ascites levels of IGF-1, IGF-2, PAPP-A, PAPP-A2, STC1, and STC2 and assessed their relationship with mortality. As compared to serum, we found highly increased ascites levels of PAPP-A (51-fold) and PAPP-A2 (4-fold). Elevated levels were also observed for IGF-1 (12%), STC1 (90%) and STC2 (68%). In contrast, IGF-2 was reduced by 29% in ascites. Patients were followed for a median of 38.4 months (range: 45 days to 8.9 years), during which 73 patients (68.2%) died. Overall survival was longer for patients with high serum IGF-1 (hazard ratio (HR) per doubling in protein concentration: 0.60, 95% CI: 0.40-0.90). However, patients with high ascites levels of IGF-1 showed a poorer prognosis (HR: 2.00 (1.26-3.27)). High serum and ascites IGF-2 levels were associated with increased risk of mortality (HR: 2.01 (1.22-3.30) and HR: 1.78 (1.24-2.54), respectively). Similarly, serum PAPP-A2 was associated with mortality (HR: 1.26 (1.08-1.48)). Our findings demonstrate the presence and activity of the IGF system in the local tumor ecosystem, which is likely a characteristic feature of malignant disease and plays a role in its peritoneal dissemination. The potential clinical implications are supported by our finding that serum levels of the proteins are associated with patient prognosis.

STC2 Inhibits Hepatic Lipid Synthesis and Correlates with Intramuscular Fatty Acid Composition, Body Weight and Carcass Traits in Chickens

Stanniocalcin 2 (STC2) is a secreted glycoprotein involved in multiple biological processes. To systemically study the biological role of STC2 in chickens, phylogenetic tree analysis and conservation analysis were conducted. Association analysis between variations in the STC2 gene and the economic traits of Gushi-Anka F2 was conducted. The tissue expression patterns of STC2 expression in different chicken tissues and liver at different stages were detected. The biological role of STC2 in chicken liver was investigated through overexpression and interfering methods in the LMH cell line. Correlation analyses between STC2 expression and lipid components were conducted. (1) The phylogenetic tree displayed that chicken STC2 is most closely related with Japanese quail and most distantly related with Xenopus tropicalis. STC2 has the same identical conserved motifs as other species. (2) rs9949205 (T > C) found in STC2 intron was highly significantly correlated with chicken body weight at 0, 2, 4, 6, 8, 10 and 12 weeks (p < 0.01). Extremely significant correlations of rs9949205 with semi-evisceration weight (SEW), evisceration weight (EW), breast muscle weight (BMW), leg muscle weight (LMW), liver weight and abdominal fat weight (AFW) were revealed (p < 0.01). Significant associations between rs9949205 and abdominal fat percentage, liver weight rate, breast muscle weight rate and leg muscle weight rate were also found (p < 0.05). Individuals with TT or TC genotypes had significantly lower abdominal fat percentage and liver weight rate compared to those with the CC genotype, while their body weight and other carcass traits were higher. (3) STC2 showed a high expression level in chicken liver tissue, which significantly increased with the progression of age (p < 0.05). STC2 was observed to inhibit the content of lipid droplets, triglycerides (TG) and cholesterol (TC), as well the expression level of genes related to lipid metabolism in LMH cells. (4) Correlation analysis showed that the STC2 gene was significantly correlated with 176 lipids in the breast muscle (p < 0.05) and mainly enriched in omega-3 and omega-6 unsaturated fatty acids. In conclusion, the STC2 gene in chicken might potentially play a crucial role in chicken growth and development, as well as liver lipid metabolism and muscle lipid deposition. This study provides a scientific foundation for further investigation into the regulatory mechanism of the STC2 gene on lipid metabolism and deposition in chicken liver.

Hepatocellular Carcinoma: Up-regulated Circular RNAs Which Mediate Efficacy in Preclinical In Vivo Models

Hepatocellular carcinoma (HCC) ranges as number two with respect to the incidence of tumors and is associated with a dismal prognosis. The therapeutic efficacy of approved multi-tyrosine kinase inhibitors and checkpoint inhibitors is modest. Therefore, the identification of new therapeutic targets and entities is of paramount importance. We searched the literature for up-regulated circular RNAs (circRNAs) which mediate efficacy in preclinical in vivo models of HCC. Our search resulted in 14 circRNAs which up-regulate plasma membrane transmembrane receptors, while 5 circRNAs induced secreted proteins. Two circRNAs facilitated replication of Hepatitis B or C viruses. Three circRNAs up-regulated high mobility group proteins. Six circRNAs regulated components of the ubiquitin system. Seven circRNAs induced GTPases of the family of ras-associated binding proteins (RABs). Three circRNAs induced redox-related proteins, eight of them up-regulated metabolic enzymes and nine circRNAs induced signaling-related proteins. The identified circRNAs up-regulate the corresponding targets by sponging microRNAs. Identified circRNAs and their targets have to be validated by standard criteria of preclinical drug development. Identified targets can potentially be inhibited by small molecules or antibody-based moieties and circRNAs can be inhibited by small-interfering RNAs (siRNAs) or short hairpin RNAs (shRNAs) for therapeutic purposes.

Inhibition of stress proteins TRIB3 and STC2 potentiates sorafenib sensitivity in hepatocellular carcinoma

Sorafenib resistance is one of the main obstacles to the treatment of advanced hepatocellular carcinoma (HCC). Stress proteins TRIB3 and STC2 confer cell resistance to a variety of stresses, including hypoxia, nutritional deprivation, and other perturbations, which induce endoplasmic reticulum stress. However, the role of TRIB3 and STC2 in sorafenib sensitivity to HCC remains unclear. In this study, our results indicated that the common differentially expressed genes (DEGs) in sorafenib-treated HCC cells obtained from the NCBI-GEO database (Huh7 and Hep3B cells; GSE96796) included TRIB3, STC2, HOXD1, C2orf82, ADM2, RRM2, and UNC93A. The most significantly upregulated DEGs were TRIB3 and STC2, which were both stress protein genes. Bioinformatic analysis in NCBI public databases indicated that TRIB3 and STC2 were highly expressed in HCC tissues and closely associated with poor prognoses in HCC patients. Further investigation showed that inhibition of TRIB3 or STC2 with siRNA could enhance the anti-cancer effect of sorafenib in HCC cell lines. In conclusion, our study showed that stress proteins TRIB3 and STC2 are closely associated with sorafenib resistance in HCC. The combination of TRIB3 or STC2 inhibition and sorafenib may be a promising therapeutic strategy for HCC.

Stanniocalcin 2 is induced by estrogen and promotes growth in endometrial cancer via AMPK pathway

Stanniocalcin 2 (STC2) is identified as a glycosylated peptide hormone and estrogen-responsive gene in cancer cells. STC2 participates in angiogenesis, cell development, cytoprotection, and calcium and phosphate regulation during the development of cancer. The role of STC2 in endometrial cancer (EC) remains unclear. The data from the bioinformatic and immunohistochemical analysis showed that STC2 was upregulated in the EC tissues. The EC cells were treated with 17β-estradiol (E2), and 0.1 μmol/L E2 increased the expression of STC2 in the EC cells. E2 also increased cell viability, promoted proliferation, and inhibited apoptosis of EC. However, the knockdown of STC2 decreased cell viability, reduced proliferation, and promoted apoptosis of E2-stimulated EC. Moreover, silencing of STC2 attenuated E2-induced downregulation of phosphorylated-AMP-activated protein kinase (AMPK) in the EC cells. The loss of STC2 reduced E2-stimulated tumor growth EC in vivo. In conclusion, STC2 deficiency suppressed E2-stimulated proliferation and tumor growth of EC through the activation of AMPK signaling.

The STC2-PAPP-A-IGFBP4-IGF1 axis and its associations to mortality and CVD in T2D

Objective

Physiologically, pregnancy-associated plasma protein-A (PAPP-A) serves to liberate bound IGF1 by enzymatic cleavage of IGF-binding proteins (IGFBPs), IGFBP4 in particular. Clinically, PAPP-A has been linked to cardiovascular disease (CVD). Stanniocalcin-2 (STC2) is a natural inhibitor of PAPP-A enzymatic activity, but its association with CVD is unsettled. Therefore, we examined associations between the STC2-PAPP-A-IGFBP4-IGF1 axis and all-cause mortality and CVD in patients with type 2 diabetes (T2D).

Design

We followed 1284 participants with T2D from the ADDITION trial for 5 years.

Methods

Circulating concentrations of STC2, PAPP-A, total and intact IGFBP4 and IGF1 and -2 were measured at inclusion. End-points were all-cause mortality and a composite CVD event: death from CVD, myocardial infarction, stroke, revascularisation or amputation. Survival analysis was performed by Cox proportional hazards model.

Results

During follow-up, 179 subjects presented with an event. After multivariable adjustment, higher levels of STC2, PAPP-A, as well as intact and total IGFBP4, were associated with all-cause mortality; STC2: hazard ratio (HR) = 1.84 (1.09-3.12) (95% CI); P = 0.023, PAPP-A: HR = 2.81 (1.98-3.98); P < 0.001, intact IGFBP4: HR = 1.43 (1.11-1.85); P = 0.006 and total IGFBP4: HR = 3.06 (1.91-4.91); P < 0.001. Higher PAPP-A levels were also associated with CVD events: HR = 1.74 (1.16-2.62); P = 0.008, whereas lower IGF1 levels were associated with all-cause mortality: HR = 0.51 (0.34-0.76); P = 0.001.

Conclusions

This study supports that PAPP-A promotes CVD and increases mortality. However, STC2 is also associated with mortality. Given that STC2 inhibits the enzymatic effects of PAPP-A, we speculate that STC2 either serves to counteract harmful PAPP-A actions or possesses effects independently of the PAPP-A-IGF1 axis.

Significance statement

PAPP-A has pro-atherosclerotic effects and exerts these most likely through IGF1. IGF1 is regulated by the STC2-PAPP-A-IGFBP4-IGF1 axis, where STC2, an irreversible inhibitor of PAPP-A, has been shown to reduce the development of atherosclerotic lesions in mice. We examined the association of this axis to mortality and CVD in T2D. We demonstrated an association between PAPP-A and CVD. All components of the STC2-PAPP-A-IGFBP4-IGF1 axis were associated with mortality and it is novel that STC2 was associated with mortality in T2D. Our study supports that inhibition of PAPP-A may be a new approach to reducing mortality and CVD. Whether modification of STC2 could serve as potential intervention warrants further investigation.

STC2 activates PRMT5 to induce radioresistance through DNA damage repair and ferroptosis pathways in esophageal squamous cell carcinoma

Radioresistance is the major reason for the failure of radiotherapy in esophageal squamous cell carcinoma (ESCC). Previous evidence indicated that stanniocalcin 2 (STC2) participates in various biological processes of malignant tumors. However, researches on its effect on radioresistance in cancers are limited. In this study, STC2 was screened out by RNA-sequencing and bioinformatics analyses as a potential prognosis predictor of ESCC radiosensitivity and then was determined to facilitate radioresistance. We found that STC2 expression is increased in ESCC tissues compared to adjacent normal tissues, and a higher level of STC2 is associated with poor prognosis. Also, STC2 mRNA and protein expression levels were higher in radioresistant cells than in their parental cells. Further investigation revealed that STC2 could interact with protein methyltransferase 5 (PRMT5) and activate PRMT5, thus leading to the increased expression of symmetric dimethylation of histone H4 on Arg 3 (H4R3me2s). Mechanistically, STC2 can promote DDR through the homologous recombination and non-homologous end joining pathways by activating PRMT5. Meanwhile, STC2 can participate in SLC7A11-mediated ferroptosis in a PRMT5-dependent manner. Finally, these results were validated through in vivo experiments. These findings uncovered that STC2 might be an attractive therapeutic target to overcome ESCC radioresistance.

Transcriptome and pan-cancer system analysis identify PM2.5-induced stanniocalcin 2 as a potential prognostic and immunological biomarker for cancers

Epidemiological studies have shown that air pollution and particulate matter (PM) are closely related to the occurrence of cancer. However, the potential prognostic and immunological biomarkers for air pollution related cancers are lacking. In this study, we proved PM2.5 exposure was correlated with lung cancer through transcriptome analysis. Importantly, we identified STC2 as a key gene regulated by PM2.5, whose expression in epithelial cells was significantly increased after PM2.5 treatment and validated by using RT-qPCR and immunofluorescence. Kaplan-Meier OS curves suggested that high STC2 expression positively correlated with a poor prognosis in lung cancer. Furthermore, we discovered that STC2 was associated with multiple cancers and pathways in cancer. Next, Pan-Cancer Expression Landscape of STC2 showed that STC2 exhibited inconsistent expression across 26 types of human cancer, lower in KIRP in cancer versus adjacent normal tissues, and significantly higher in another cancers. Cox regression results suggested that STC2 expression was positively or negatively associated with prognosis in different cancers. Moreover, STC2 expression was associated with clinical phenotypes including age, gender, stage and grade. Mutation features of STC2 were also analyzed, in which the highest alteration frequency of STC2 was presented in KIRC with amplification. Meanwhile, the effects of copy number variation (CNV) on STC2 expression were investigated across various tumor types, suggesting that STC2 expression was significantly correlated with CNV in tumors. Additionally, STC2 was closely related to tumor heterogeneity, tumor stemness and tumor immune microenvironment like immune cell infiltration. In the meantime, we analyzed methylation modifications and immunological correlation of STC2. The results demonstrated that STC2 expression positively correlated with most RNA methylation genes and immunomodulators across tumors. Taken together, the findings revealed that PM2.5-induced STC2 might be a potential prognostic and immunological biomarker for cancers related to air pollution.

Characterization of a lipid droplet and endoplasmic reticulum stress related gene risk signature to evaluate the clinical and biological value in hepatocellular carcinoma

INTRODUCTION

Lipid metabolism and endoplasmic reticulum (ER) stress play an important role in the progression and metastasis of hepatocellular carcinoma (HCC). We aimed to establish lipid droplet (LD)-associated and ER stress-related gene risk signature as prognostic indicators.

MATERIALS AND METHODS

Literature searches for LD-associated proteins was screened and validated in The Cancer Genome Atlas (TCGA) and International Cancer Genome Collaboratory (ICGC) databases. A total of 371 samples were enrolled from the TCGA RNA-seq dataset (training cohort) and 240 samples from IGGC RNA-seq dataset (validation cohort). A 10-gene risk signature was established by the last absolute shrinkage and selection operator (LASSO) regression analysis. The prognostic value of the risk signature was evaluated by Cox regression, Kaplan-Meier and ROC Curve analyses. Biological features associated with LD and ER stress-related factors were explored by functional analysis and in vitro experiment.

RESULTS

Based on the medical literatures, 124 lipid droplet-associated proteins were retrieved, and three genes failed to establish a valid prognostic model. ER stress was considered as an important component by functional analysis. A 10-gene risk signature compared the clinicopathology characteristics, immunosuppressive events and a nomogram in HCC patients.

CONCLUSION

LD-associated and ER stress-related gene risk signatures highlighted poor prognosis for clinicopathological features, positively correlate with macrophages and T cell immunoglobulin and mucin-3 (TIM-3) expression in the tumor microenvironment, and might act as independent prognostic factors.

Diagnostic and prognostic value of Stanniocalcin 1 expression in papillary thyroid cancer

PURPOSE

To evaluate the potential role of immunohistochemical changes in stanniocalcin 1 (STC1) and stanniocalcin 2 (STC2) expressions in papillary thyroid cancer (PTC) tissues in the disease's diagnosis and to investigate their relationship with classical clinicopathological prognostic factors.

METHODS

The study included 100 patients with PTC. Normal thyroid tissue adjacent to the tumor was taken as the control group. Clinicopathological prognostic features at the time of diagnosis of patients were recorded. STC1 and STC2 expressions of tumor tissue and adjacent normal tissue were determined immunohistochemically.

RESULTS

The sensitivity of STC1 in the diagnosis of PTC was 93%, the specificity was 94%, positive predictive value (PPV) 93.9%, and negative predictive value (NPV) 93.1%. It was determined that the STC1 staining score in tumor tissue was positively correlated with the disease TNM stage score (r = 0.259, p = 0.009) and the increase in STC1 staining score were independent risk factors that increased the risk of lymph node metastasis (R² = 0.398, p < 0.001). While 21% of the tumor tissues were stained with STC2, none of the normal thyroid tissues adjacent to the tumor tissue showed any staining with STC2. No correlation was found between STC2 immunohistochemical staining of tumor tissue and clinicopathological risk factors for the disease.

CONCLUSION

Increased STC1 expression in thyroid lesions may be helpful in diagnosing PTC. In addition, since increased STC1 expression in PTC tissues is associated with the risk of lymph node metastasis, it may be an efficient marker for predicting the prognosis of the disease.

Glycometabolism-related gene signature of hepatocellular carcinoma predicts prognosis and guides immunotherapy

Hepatocellular carcinoma (HCC) is a severe cancer endangering human health. We constructed a novel glycometabolism-related risk score to predict prognosis and immunotherapy strategies in HCC patients. The HCC data sets were obtained from the Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) database, and the glycometabolism-related gene sets were obtained from the Molecular Signature Database. The least absolute contraction and selection operator (LASSO) regression model was used to construct a risk score based on glycometabolism-related genes. A simple visual nomogram model with clinical indicators was constructed and its effectiveness in calibration, accuracy, and clinical value was evaluated. We also explored the correlation between glycometabolism-related risk scores and molecular pathways, immune cells, and functions. Patients in the low-risk group responded better to anti-CTLA-4 immune checkpoint treatment and benefited from immune checkpoint inhibitor (ICI) therapy. The study found that glycometabolism-related risk score can effectively distinguish the prognosis, molecular and immune-related characteristics of HCC patients, and may provide a new strategy for individualized treatment.

Unfolded Protein Response-Related Signature Associates With the Immune Microenvironment and Prognostic Prediction in Osteosarcoma

Background: Osteosarcoma is a highly malignant bone tumor commonly occurring in adolescents with a poor 5-year survival rate. The unfolded protein response (UPR) can alleviate the accumulation of misfolded proteins to maintain homeostasis under endoplasmic reticulum stress. The UPR is linked to the occurrence, progression, and drug resistance of tumors. However, the function of UPR-related genes (UPRRGs) in disease progression and prognosis of osteosarcoma remains unclear.

Methods: The mRNA expression profiling and corresponding clinical features of osteosarcoma were acquired from TARGET and GEO databases. Consensus clustering was conducted to confirm different UPRRG subtypes. Subsequently, we evaluated the prognosis and immune status of the different subtypes. Functional analysis of GO, GSEA, and GSVA was used to reveal the molecular mechanism between the subtypes. Finally, four genes (STC2, PREB, TSPYL2, and ATP6V0D1) were screened to construct and validate a risk signature to predict the prognosis of patients with osteosarcoma.

Result: We identified two subtypes according to the UPRRG expression patterns. The subgroup with higher immune scores, lower tumor purity, and active immune status was linked to a better prognosis. Meanwhile, functional enrichment revealed that immune-related signaling pathways varied markedly in the two subtypes, suggesting that the UPR might influence the prognosis of osteosarcoma via influencing the immune microenvironment. Moreover, prognostic signature and nomogram models were developed based on UPRRGs, and the results showed that our model has an excellent performance in predicting the prognosis of osteosarcoma. qPCR analysis was also conducted to verify the expression levels of the four genes.

Conclusion: We revealed the crucial contribution of UPRRGs in the immune microenvironment and prognostic prediction of osteosarcoma patients and provided new insights for targeted therapy and prognostic assessment of the disease.

Identification and Validation of a Prognostic Immune-Related Gene Signature in Esophageal Squamous Cell Carcinoma

Esophageal carcinoma (EC) is a common malignant cancer worldwide. Esophageal squamous cell carcinoma (ESCC), the main type of EC, is difficult to treat because of the widespread morbidity, high fatality rates, and low quality of life caused by postoperative complications and no specific molecular target. In this study, we screened genes to establish a prognostic model for ESCC. The transcriptome expression profiles of 81 ESCC tissues and 340 normal esophageal mucosal epithelium tissues were obtained from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) cohorts. The transcriptome expression datasets of 19 esophageal squamous carcinoma cell lines were downloaded from Cancer Cell Line Encyclopedia (CCLE). The R software Limma package was used to identify 6,231 differentially expressed genes and 647 differentially expressed immune-related genes between normal and ESCC tissues. Gene functional analysis was performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Weighted gene co-expression network analysis (WGCNA) was used to screen out 18 immune-related prognostic genes. We then established the prognostic and risk signature using these genes, and the patients were divided into low-risk and high-risk groups. Compared with high-risk group patients, the low-risk group patients had longer overall survival. M1 macrophages and resting dendritic cells were differentially distributed between the low-risk and high-risk groups and were related to patient survival. We also examined the functional immune cell and immune molecule levels in low-risk and high-risk group patients, with significant differences in the tumor microenvironment between the two groups. To further verify the accuracy of the prognostic risk model, we performed area under the ROC curve (AUC) analysis. The AUC value was 0.931 for the prognostic risk, which was better than the microsatellite instability (MSI) and Tumor Immune Dysfunction and Exclusion (TIDE) scores. In conclusion, we found 18 immune-related prognostic genes related to the occurrence of ESCC and established a prognostic model for predicting disease severity.