Spondin2 is a new prognostic biomarker for lung adenocarcinoma

The biological functions and related signaling pathways of SPON2

Spondin-2 (SPON2), also referred to as M-spondin or DIL-1, is a member of the extracellular matrix protein family known as Mindin-F-spondin (FS). SPON2 can be used as a broad-spectrum tumor marker for more than a dozen tumors, mainly prostate cancer. Meanwhile, SPON2 is also a potential biomarker for the diagnosis of certain non-tumor diseases. Additionally, SPON2 plays a pivotal role in regulating tumor metastasis and progression. In normal tissues, SPON2 has a variety of biological functions represented by promoting growth and development and cell proliferation. This paper presents a comprehensive overview of the regulatory mechanisms, diagnostic potential as a broad-spectrum biomarker, diverse biological functions, involvement in various signaling pathways, and clinical applications of SPON2.

Comprehensive analysis of the oncogenic and immunological role of SPON2 in human tumors

BACKGROUND

Sapiens spondin-2 (SPON2) is a protein found in the extracellular matrix that plays a role in a number of processes, including immune reactions and cell adhesion, and is closely linked to the emergence of a number of tumor types. However, we know very little about Sapiens spondin-2. Therefore, we performed a systematic pan-carcinogenic analysis to explore the relationship between Sapiens spondin-2 and cancers.

MATERIALS AND METHODS

By comprehensive use of datasets from TCGA, GEO, GTEx, HPA, CPTAC, GEPIA2, TIMER2, cBioPortal, STRING, we adopted bioinformatics methods to dig up the potential carcinogenesis of SPON2, including dissecting the correlation between SPON2 and gene expression, prognosis, gene mutation, Immunohistochemistry staining, immune cell infiltration, and constructed the interaction network of a total of 54 SPON2-binding proteins as well as explored the enrichment analysis of SPON2-related partners.

RESULTS

The expression of Sapiens spondin-2 in most tumor tissues was higher than that of normal tissues. In addition, SPON2 showed the early diagnostic value in 33 kinds of tumors and was positively or negatively associated with the prognosis of different tumors. It also validates that SPON2 is the gene associated with the majority of immune-infiltrating cells in pan-cancer. High SPON2 expression is associated with tumor progression related pathways.

CONCLUSION

We found and validated the potential use of SPON2 in cancer detection for the first time through pan-cancer analysis. The expression levels of SPON2 in various tumors were quite different from those in normal tissues. Furthermore, the performance of SPON2 in tumorigenesis and tumor immunity verified our hypothesis. At the same time, it has high specificity and sensitivity in cancer detection. Therefore, SPON2 can be employed as an auxiliary index for the initial diagnosis of tumors and a prognostic marker for various types of tumors.

Identification of THSD7B and PRMT9 mutations as risk factors for familial lung adenocarcinoma: A case report

RATIONALE

Lung tumors arise from the unrestrained malignant growth of pulmonary epithelial cells. Lung cancer cases include both small and non-small cell lung cancers, with lung adenocarcinoma (LUAD) accounting for roughly half of all non-small cell lung cancer cases. Research focused on familial cancers suggests that approximately 8% of lung cancer cases are linked to genetic susceptibility or heritability. The precise genetic factors that underlie the onset of lung cancer, however, remain to be firmly established.

PATIENT CONCERNS

A 43-year-old presented with nodules in the lower left lung lobe. Following initial antibiotic treatment in a local hospital, these nodules remained present and the patient subsequently underwent the resection of the left lower lobe of the lung. The patient also had 4 family members with a history of LUAD.

DIAGNOSIS

Immunohistochemical staining results including cytokeratin 7 (+), TTF-1 (+), new aspartic proteinase A (+), CK5/6 (-), P63 (-), and Ki-67 (5%+) were consistent with a diagnosis of LUAD.

INTERVENTION

Whole exome sequencing analyses of 5 patients and 6 healthy family members were performed to explore potential mutations associated with familial LUAD.

OUTCOMES

Whole exome sequencing was conducted, confirming that the proband and their 4 other family members with LUAD harbored heterozygous THSD7B (c.A4000G:p.S1334G) mutations and homozygous PRMT9 (c.G40T:p.G14C) mutations, as further confirmed via Sanger sequencing. These mutations were predicted to be deleterious using the SIFT, PolyPhen2, and MutationTaster algorithms. Protein structure analyses indicated that the mutation of the serine at amino acid position 1334 in THSD7B to a glycine would reduce the minimum free energy from 8.08 kcal/mol to 68.57 kcal/mol. The identified mutation in the PRMT9 mutation was not present in the predicted protein structure. I-Mutant2.0 predictions indicated that both of these mutations (THSD7B:p.S1334G and PRMT9: p.G14C) were predicted to reduce protein stability.

LESSONS

Heterozygous THSD7B (c.A4000G:p.S1334G) and the homozygous PRMT9 (c.G40T:p.G14C) mutations were found to be linked to LUAD incidence in the analyzed family. Early analyses of these genetic loci and timely genetic counseling may provide benefits and aid in the early diagnosis of familial LUAD.

SPON2 promotes the bone metastasis of lung adenocarcinoma via activation of the NF-κB signaling pathway

Bone metastasis severely affects the life span and quality of life of survivors of lung adenocarcinoma (ADC). There is a pressing need to identify viable biomarkers for this incurable, fatal disease. Spondin-2 (SPON2) has been reported to be involved in metastasis and cancer progression, but its role in bone metastasis in patients with lung ADC has rarely been studied. Here, we showed that the upregulation of SPON2 increased the migration, invasion, and epithelial-to-mesenchymal transition of ADC cells in vitro, whereas silencing SPON2 repressed these processes. Consistently, silencing SPON2 significantly reduced the bone metastasis of ADC cells in vivo. Mechanistically, SPON2 activated the nuclear factor-κB (NF-κB) signaling pathway and increased the expression levels of MMP2 and MMP9. Blocking NF-κB using an inhibitor attenuated the SPON2-induced migration and invasion of ADC cells. In addition, we found that SPON2 expression levels were increased in metastatic bone tissues compared to primary ADC tissues. The upregulation of SPON2 was positively correlated with MMP2 and MMP9 expression levels in metastatic bone tissues. In conclusion, these results illustrate that SPON2 plays a key role in ADC by activating the NF-κB pathway to promote bone metastasis, which suggests that it may be a target for future drug development.

Serum Spondin-2 expression, tumor invasion, and antitumor immune response in patients with cervical cancer

BACKGROUND

Cervical cancer is a gynecological malignancy common in middle-aged and older patients, with a high mortality rate. Spondin-2 is an extracellular matrix protein that involved in innate and acquired immune responses. Herein, we investigated the relationship between serum Spondin-2 expression, tumor invasion and infiltration, and immune response in patients with cervical cancer and provided a theoretical basis for clinical practice.

AIM

To investigate the relationship between serum Spondin-2 expression and cervical cancer-related indicators.

METHODS

Overall, 147 patients with cervical cancer who were admitted to our institution between January 2019 and August 2019 were assigned to the cervical cancer group, and 92 patients with benign uterine lesions and 86 healthy individuals were assigned to the benign and control groups, respectively. In each group, serum Spondin-2 expression was measured, and the receiver operating characteristic (ROC) curve was determined. Patients with cervical cancer were classified into high or low Spondin-2 groups depending on the Spondin-2 threshold value used for diagnosing cervical cancer. Patient’s clinical data were collected to compare the clinicopathologic characteristics, immune cytokine levels, and prognosis of patients with varying Spondin-2 expression levels.

RESULTS

The expression level of serum Spondin-2 was significantly higher in the cervical cancer group than in the benign and control groups (P < 0.05). According to the ROC curve, the cutoff value of Spondin-2 used in the diagnosis of cervical carcinoma was 25.68 ± 7.11 μg/L. The proportion of patients with Federation of Gynecology and Obstetrics stage III, nerve invasion, vascular invasion, and lymph node metastasis was higher in the high Spondin-2 group than in the low Spondin-2 group (P < 0.05). Interleukin-5 (IL-5) and IL-4 Levels were higher in the high Spondin-2 group than in the low Spondin-2 group. In contrast, IL-2 and tumor necrosis factor-α levels were lower in the high Spondin-2 group than in the low Spondin-2 group (P < 0.05). After 3 years of follow-up, progression-free survival and overall survival were significantly shorter in the high Spondin-2 group than in the low Spondin-2 group (P < 0.05).

CONCLUSION

The expression of serum Spondin-2 is upregulated in patients with cervical carcinoma and is related to tumor invasion and infiltration, antitumor immune response, and prognosis.

Mindin (SPON2) Is Essential for Cutaneous Fibrogenesis in a Mouse Model of Systemic Sclerosis

Systemic sclerosis is a fibrotic disease that initiates in the skin and progresses to internal organs, leading to a poor prognosis. Unraveling the etiology of a chronic, multifactorial disease such as systemic sclerosis has been aided by various animal models that recapitulate certain aspects of the human pathology. We found that the transcription factor SNAI1 is overexpressed in the epidermis of patients with systemic sclerosis, and a transgenic mouse recapitulating this expression pattern is sufficient to induce many clinical features of the human disease. Using this mouse model as a discovery platform, we have uncovered a critical role for the matricellular protein Mindin (SPON2) in fibrogenesis. Mindin is produced by SNAI1 transgenic skin keratinocytes and aids fibrogenesis by inducing early inflammatory cytokine production and collagen secretion in resident dermal fibroblasts. Given the dispensability of Mindin in normal tissue physiology, targeting this protein holds promise as an effective therapy for fibrosis.

Tumor-derived exosomal HOTAIRM1 regulates SPON2 in CAFs to promote progression of lung adenocarcinoma

OBJECTIVE

SPON2 is one of the extracellular matrix proteins, which is closely related to the progression of a variety of tumors including non-small cell lung cancer (NSCLC), but its upstream regulation mechanism remains unclear. Our research aims to find the specific regulatory pathway of SPON2 by exploring the potential crosstalk between tumor cells and cancer-associated fibroblasts (CAFs) in tumor microenvironment (TME) of NSCLC.

METHODS

We analyzed T1 lung adenocarcinoma samples from TCGA and screened extracellular matrix proteins that indicate poor prognosis. Expression level of SPON2 was verified by qPCR in clinical samples. The exosomes of NSCLC cell supernatant were extracted and identified by nanoparticle tracking analysis (NTA) and transmission electron microscope, western blots. The exosomes and CAFs were co-cultured, and cell migration and Matrigel invasion assay were used to evaluate the effect of CAFs on the migration and invasion of NSCLC cells. The interaction between LncRNA and miRNA was verified by Targetscan prediction, luciferase reporter assay, and RNA binding protein immunoprecipitation (RIP).

RESULTS

We found that the expression of SPON2 was up-regulated in clinical T1a stage NSCLC patients. The expression of lnc HOTAIRM1 (HOTAIRM1) in exosomes secreted by NSCLC tissues increased. After exosomal HOTAIRM1 entered CAFs, HOTAIRM1 can adsorb miR-328-5p to up-regulate the expression of SPON2 in CAFs. Up-regulation of SPON2 in CAFs could promote the migration and invasion of NSCLC cells.

CONCLUSION

Tumor-derived exosomal HOTAIRM1 can transfer into CAFs and competitively adsorb miR-328-5p, and regulate the SPON2 expression of CAFs cells, ultimately promote the progression of NSCLC. The discovery of this regulatory pathway can provide a new potential therapeutic target for the diagnosis and treatment of NSCLC.

Snail maintains the stem/progenitor state of skin epithelial cells and carcinomas through the autocrine effect of matricellular protein Mindin

Preservation of a small population of cancer stem cells (CSCs) within a heterogeneous carcinoma serves as a paradigm to understand how select cells in a tissue maintain their undifferentiated status. In both embryogenesis and cancer, Snail has been correlated with stemness, but the molecular underpinning of this phenomenon remains largely ill-defined. In models of cutaneous squamous cell carcinoma (cSCC), we discovered a non-epithelial-mesenchymal transition function for the transcription factor Snail in maintaining the stemness of epidermal keratinocytes. Snail-expressing cells secrete the matricellular protein Mindin, which functions in an autocrine fashion to activate a Src-STAT3 pathway to reinforce their stem/progenitor phenotype. This pathway is activated by the engagement of Mindin with the leukocyte-specific integrin, CD11b (ITGAM), which is also unexpectedly expressed by epidermal keratinocytes. Interestingly, disruption of this signaling module in human cSCC attenuates tumorigenesis, suggesting that targeting Mindin would be a promising therapeutic approach to hinder cancer recurrence.

The Extracellular Matrix-Derived Biomarkers for Diagnosis, Prognosis, and Personalized Therapy of Malignant Tumors

The tumor biomarkers already have proven clinical value and have become an integral part in cancer management and modern translational oncology. The tumor tissue microenvironment (TME), which includes extracellular matrix (ECM), signaling molecules, immune and stromal cells, and adjacent non-tumorous tissue, contributes to cancer pathogenesis. Thus, TME-derived biomarkers have many clinical applications. This review is predominately based on the most recent publications (manuscripts published in a last 5 years, or seminal publications published earlier) and fills a gap in the current literature on the cancer biomarkers derived from the TME, with particular attention given to the ECM and products of its processing and degradation, ECM-associated extracellular vesicles (EVs), biomechanical characteristics of ECM, and ECM-derived biomarkers predicting response to the immunotherapy. We discuss the clinical utility of the TME-incorporating three-dimensional in vitro and ex vivo cell culture models for personalized therapy. We conclude that ECM is a critical driver of malignancies and ECM-derived biomarkers should be included in diagnostics and prognostics panels of markers in the clinic.

Overexpression of Spondin-2 Is Associated with Recurrence-Free Survival in Patients with Localized Clear Cell Renal Cell Carcinoma

Background

The spondin-2 (SPON2) gene is overexpressed in multiple malignant tumors and may promote tumor aggressiveness. However, its expression profile and functional roles in clear cell renal cell carcinoma (ccRCC) are still unclear.

Methods

SPON2 expression in ccRCC was evaluated using expression data from TCGA and GEO databases, then confirmed by local patient population (94 patients). The clinical significance of SPON2 expression was evaluated. Downregulation of SPON2 was performed using small-interfering RNA (siRNA). The effects of SPON2 silencing on cell proliferation, apoptosis, invasion, and migration in vitro were investigated.

Results

SPON2 was overexpressed in the majority of the ccRCC at both mRNA and protein levels. SPON2 expression was significantly correlated with stage, grade, and recurrence (all P < 0.05) in patients with localized ccRCC. The receiver operating characteristic (ROC) curve showed that SPON2 expression could serve as a predictor of recurrence. SPON2 expression was significantly associated with recurrence-free survival (RFS) in patients with localized ccRCC. Knocking down SPON2 resulted in suppressed cell invasion and migration in vitro.

Conclusion

SPON2 expression might function as a prognostic biomarker in patients with localized ccRCC.

Spondin 2 promotes the proliferation, migration and invasion of gastric cancer cells

Spondin 2 (SPON2), a member of the Mindin F‐Spondin family, identifies pathogens, activates congenital immunity and promotes the growth and adhesion of neurons as well as binding to their receptors, but its role in promoting or inhibiting tumour metastasis is controversial. Here, we investigated its expression levels and mechanism of action in gastric cancer (GC). Western blotting and GC tissue arrays were used to determine the expression levels of SPON2. ELISAs were performed to measure the serum levels of SPON2 in patients with GC. Two GC cell lines expressing low levels of SPON2 were used to analyse the effects of regulating SPON2 expression on proliferation, migration, invasion, the cell cycle and apoptosis. The results revealed that SPON2 was highly expressed in GC tissues from patients with relapse or metastasis. The levels of SPON2 in sera of patients with GC were significantly higher compared with those of healthy individuals and patients with atrophic gastritis. Knockdown of SPON2 expression significantly inhibited the proliferation, migration and invasion of GC cells in vitro and in vivo. Down‐regulation of SPON2 arrested the cell cycle in G1/S, accelerated apoptosis through the mitochondrial pathway and inhibited the epithelial‐mesenchymal transition by blocking activation of the ERK1/2 pathway. In summary, this study suggests that SPON2 acts as an oncogene in the development of GC and may serve as a marker for the diagnosing GC as well as a new therapeutic target for GC.

Upregulation of Spondin-2 protein expression correlates with poor prognosis in hepatocellular carcinoma

OBJECTIVE

The aim of this study was to measure the extracellular matrix protein Spondin-2 (SPON2) in hepatocellular carcinoma (HCC) tissues and to determine its potential value as a prognostic indicator by assessing its correlation with clinicopathological variables and survival.

METHODS

SPON2 mRNA expression was assessed in 20 matched pairs of HCC and non-cancerous liver tissues by quantitative reverse transcription-polymerase chain reaction analysis. SPON2 protein expression was determined in 107 matched pairs of HCC and normal liver tissue by immunohistochemical staining of tissue microarrays.

RESULTS

Analysis of patient tissues and Oncomine datasets showed that SPON2 mRNA and SPON2 protein expression were both significantly upregulated in HCC tissues, compared with non-cancerous liver tissue; moreover, both correlated significantly with tumor size. Kaplan-Meier analysis revealed that HCC patients who showed high levels of cytoplasmic SPON2 protein had poorer survival following curative resection, compared with HCC patients who exhibited low protein expression levels. Multivariate Cox regression analysis showed that tumor thrombus and SPON2 protein expression both independently correlated with reduced survival in HCC patients.

CONCLUSION

Upregulated expression of SPON2 protein in tumor tissue could be an effective prognostic indicator for patients with HCC.