SPARCL1 is a novel predictor of tumor recurrence and survival in hilar cholangiocarcinoma

SPARCL1 Is a Novel Prognostic Biomarker and Correlates with Tumor Microenvironment in Colorectal Cancer

Background

Secreted protein acidic and rich in cysteine-like 1 (SPARCL1) plays an important role in tumor pathogenesis. We aim to evaluate the clinical significance and potential biological roles of SPARCL1 in colorectal cancer (CRC).

Methods

Datasets from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were downloaded to evaluate the expression levels of SPARCL1 in CRC. Receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic value of SPARCL1. Then, comprehensive database search was conducted for published clinical studies to explore clinical significance of SPARCL1. In addition, coexpression genes of SPARCL1 were identified through the cBioPortal database and enrichment analysis of SPARCL1 and its coexpression genes were performed by the “clusterProfiler” R package. Finally, the correlations between SPARCL1 and tumor microenvironment scores, tumor-infiltrating immune cells in CRC were determined by “ESTIMATE” and “GSVA” R packages.

Results

SPARCL1 was significantly downregulated in CRC tissues, and SPARCL1 showed high accuracy for diagnosis of primary CRC in both GEO and TCGA datasets. Pooled results from published clinical studies showed SPARCL1 expression was associated with differentiation (OR = 1.89, 95% CI: 1.38-2.59), tumor stage (OR = 0.47, 95% CI: 0.29-0.77), distant metastasis (OR = 0.53, 95% CI: 0.33-0.84), and overall survival (HR = 0.56, 95% CI: 0.43-0.74). SPARCL1 and its top 300 coexpression genes were involved in several KEGG pathways, such as focal adhesion, cell adhesion molecules, PI3K-Akt signaling pathway, cGMP-PKG signaling pathway, and ECM-receptor interaction. Besides, the SPARCL1 expression was significantly correlated with stromal score, immune score, ESTIMATE score, and diverse immune cells.

Conclusion

SPARCL1 significantly correlated with clinicopathological features and tumor microenvironment in CRC.

Species-, organ- and cell-type-dependent expression of SPARCL1 in human and mouse tissues

SPARCL1 is a matricellular protein with anti-adhesive, anti-proliferative and anti-tumorigenic functions and is frequently downregulated in tumors such as colorectal carcinoma or non-small cell lung cancer. Studies have identified SPARCL1 as an angiocrine tumor suppressor secreted by tumor vessel endothelial cells, thereby exerting inhibitory activity on angiogenesis and tumor growth, in colorectal carcinoma. It is unknown whether SPARCL1 may exert these homeostatic functions in all organs and in other species. Therefore, SPARCL1 expression was comparatively analysed between humans and mice in a systematic manner. Murine Sparcl1 (mSparcl1) is most strongly expressed in the lung; expressed at an intermediate level in most organs, including the large intestine; and absent in the liver. In human tissues, SPARCL1 (hSPARCL1) was detected in all organs, with the strongest expression in the stomach, large intestine and lung, mostly consistent with the murine expression pattern. A striking difference between human and murine tissues was the absence of mSparcl1 expression in murine livers, while human livers showed moderate expression. Furthermore, mSparcl1 was predominantly associated with mural cells, whereas hSPARCL1 was detected in both mural and endothelial cells. Human SPARCL1 expression was downregulated in different carcinomas, including lung and colon cancers. In conclusion, this study revealed species-, organ- and cell-type-dependent expression of SPARCL1, suggesting that its function may not be similar between humans and mice.

SPARCL1 impedes trophoblast migration and invasion by down-regulating ERK phosphorylation and AP-1 production and altering EMT-related molecule expression

INTRODUCTION

Embryo implantation depends on trophoblast cells migration and invasion. Abnormal function of trophoblast cells could result in many pregnancy complications. Secreted protein acidic and rich in cysteine like-1 (SPARCL1) has been reported to inhibit cell migration and tumor invasion. This study aimed to explore the role of SPARCL1 in trophoblast functions.

METHODS

Villous specimens were obtained from 31 women with spontaneous abortion and 31 women with normal early pregnancy to determine the expression of SPARCL1. HTR8/SVneo cells and JAR cells were transfected with pIRES2-EGFP-SPARCL1 vectors and control vectors. The proliferation assay and scratch-wound assay were performed. Quantitative polymerase chain reaction (qPCR) and western blotting were performed to assess epithelial mesenchymal transition (EMT)-related molecules including MMP2, MMP3, N-cadherin, E-cadherin and vimentin. Extracellular signal-regulated kinase (ERK) phosphorylation activity and AP-1 expression in HTR8/SVneo cells following multi-scratching were detected using above assays.

RESULTS

The mRNA and protein levels of SPARCL1 were significantly higher in the abortion group than in the normal pregnancy group. After transfection, there was no difference of cell viability between the SPARCL1-overexpression group and control vector group. However, the migration distance and area were reduced and the abundances of EMT related molecules were changed by SPARCL1 overexpression when compared with controls. Lower ERK phosphorylation activity and decreased Fos and Jun expressions were noted at high level of SPARCL1.

CONCLUSION

Restrained migration and invasion were noted in trophoblast cells with SPARCL1 overexpression, which might affect embryo implantation and placenta development. It could be involved in the pathogenesis of spontaneous abortion.

Multi-platform analysis of methylation-regulated genes in human lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most frequent pathological type of lung cancer that has a poor prognosis and high mortality rate. DNA methylation plays a critical role in various biological processes during development, while dysregulation results in pathological consequences. Thus, this study aimed to identify DNA methylation-regulated genes involved in LUAD occurrence. Initially, 300 downregulated and 168 upregulated mRNA expression levels were identified in two databases: Gene Expression Omnibus (GEO) and The Cancer Genome Atlas. In addition, GEO was utilized to detect 243 DNA hyper-methylated sites. Based on our observations, it was possible to correlate downregulation of mRNA expression and DNA hyper-methylation of six genes (ABCA3, COX7A1, HOXA5, SLIT3, SOX17, and SPARCL1). Functional analysis of the six genes indicated that these genes are predominantly enriched in cancer-related pathways and may promote carcinogenesis by regulating epithelialmesenchymal transition processes. In conclusion, our study identified a panel of DNA methylation-regulated genes involved in LUAD and may serve as potential epigenetic markers for this type of carcinoma.

Secreted protein acidic and rich in cysteine-like 1 suppresses metastasis in gastric stromal tumors

BACKGROUND

Malignant growth and metastasis of gastrointestinal stromal tumors (GIST) occur in some patients even during the course of treatment, but their mechanisms remains poorly understand at the molecular level so far.

METHODS

Profiles of protein expression in gastric GIST tissues were explored using protein microarray analysis, down-regulation of SPARCL1 (secreted protein acidic and rich in cysteine-like protein 1) was validated by RT-qPCR, western blot and immunohistochemistry. The effect of specific shRNA-induced SPARCL1 downregulation on the biological traits of GIST 882 cell was investigated. We then employed a mouse xenograft model to investigate whether the low-expression of SPARCL1 impact the metastasis ability of GIST cells in vivo.

RESULTS

SPARCL1 was significantly downregulated in the gastric GIST with high-grade malignance as compared with low-grade malignance, its expression was closely correlated with tumor size, mitotic index, distant metastasis at the time of initial diagnosis and tumor progression of GIST (P < 0.05). Moreover, results of the Cox analysis showed that expression of SPARCL1 is an independent prognostic predictors for gastric GIST (P = 0.008; HR 0.157, 95% CI 0.040~ 0.612). Downregulation of SPARCL1 promoted cell migration and invasion, but did not affect proliferation, cell cycle and apoptosis of GIST 882 cells. In mouse xenograft model, GIST cells with the decreased expression of SPARCL1 presented an enhanced ability of liver metastasis (P < 0.05).

CONCLUSIONS

Taken together, our present study demonstrated that SPARCL1 have a certain degree of malignancy-suppressing potential through inhibiting the metastasis of gastric GIST.

Associations of tumor suppressor SPARCL1 with cancer progression and prognosis

SPARC-like protein 1 (SPARCL1), a member of the family of secreted proteins which is acidic and rich in cysteine, is a potential tumor suppressor gene in most types of tumor. A systemic review and bioinformatics analysis was carried out to determine the associations between SPARCL1 and tumor progression and clinical factors. Downregulation of SPARCL1, thought to be regulated by epigenetic modifications including DNA methylation, serves important functions in tumor progression and development, with its regulatory functions on cell viability, migration, invasion, cell adhesion and drug resistance. Downregulation of SPARCL1 was markedly associated with a poor overall survival rate of patients with one of ≥7 solid tumors and predicted increased mortality in patients with one of ≥4 distinct tumor types. The present review indicated that SPARCL1 may be a therapeutic target for cancer treatment and a biomarker to determine prognosis.