Thrombospondins in cancer

THBS2 promotes gastric cancer progression and stemness via the Notch signaling pathway

Thrombospondin-2 (THBS2), a secreted extracellular matrix protein, plays a crucial role in various biological processes including angiogenesis, tissue remodeling, and inflammation. Our study focuses on its function in human gastric cancer (GC). Through bioinformatics and tumor tissue analysis, we compared THBS2 expression in GC tissues and adjacent tissues, and predicted regulatory upstream and downstream molecules. The direct regulatory effect of miR-29b-3p on THBS2 was evaluated through dual-luciferase reporter assays, showing that miR-29b-3p targets the 3'-UTR of THBS2 mRNA, reducing its expression in GC cells. The influence of THBS2 on tumorigenesis and stemness was examined on protein expression levels via Western blot. In vivo, THBS2's role was investigated through xenograft and metastasis assays in nude mice, demonstrating that downregulation of THBS2 impairs GC tumorigenesis and liver metastasis. Our study identified THBS2 as a highly expressed prognostic factor in GC patients. Functionally, THBS2 promotes GC progression through the Notch signaling pathway by regulating Notch3, NEY1, and HES1 proteins, and sustains cancer stem cell-like characteristics by Notch3, including the expression of CD44, Nanog, OCT4, and SOX2. In sum, our study reveals that THBS2 promotes GC progression and stemness, modulated negatively by miR-29b-3p. This suggests potential therapeutic targets within the THBS2/Notch signaling axis for combating gastric cancer.

Tumor microenvironment of cancer stem cells: Perspectives on cancer stem cell targeting

There are few tumor cell subpopulations with stem cell characteristics in tumor tissue, defined as cancer stem cells (CSCs) or cancer stem-like cells (CSLCs), which can reconstruct neoplasms with malignant biological behaviors such as invasiveness via self-renewal and unlimited generation. The microenvironment that CSCs depend on consists of various cellular components and corresponding medium components. Among these factors existing at a variety of levels and forms, cytokine networks and numerous signal pathways play an important role in signaling transduction. These factors promote or maintain cancer cell stemness, and participate in cancer recurrence, metastasis, and resistance. This review aims to summarize the recent molecular data concerning the multilayered relationship between CSCs and CSC-favorable microenvironments. We also discuss the therapeutic implications of targeting this synergistic interplay, hoping to give an insight into targeting cancer cell stemness for tumor therapy and prognosis.

hsa_circ_0007919 promotes pancreatic cancer metastasis by modulating Sp1-mediated THBS1 transcription

CircRNAs are abnormally expressed in various cancers and play an important role in the occurrence and development of cancers. However, their biological functions and the underlying molecular mechanisms in pancreatic cancer (PC) metastasis are incompletely understood. Differentially expressed circRNAs were identified by second-generation transcriptome sequencing in three pairs of PC tissues and adjacent tissues. The expression and prognostic significance of hsa_circ_0007919 were evaluated by qRT-PCR and Kaplan-Meier survival curves. Gain- and loss-of-function assays were conducted to detect the role of hsa_circ_0007919 in PC metastasis in vitro. A lung metastasis model and IHC experiments were conducted to confirm the effects of hsa_circ_0007919 on tumor metastasis in vivo. Mechanistically, RNA immunoprecipitation and chromatin immunoprecipitation assays were conducted to explore the interplay among hsa_circ_0007919, Sp1, and the THBS1 promoter. hsa_circ_0007919 was significantly upregulated in PC tissues and cells and was correlated with lymph node metastasis, TNM stage, and poor prognosis. Knockdown of hsa_circ_0007919 significantly suppressed the migration and invasion of PC cells in vitro and inhibited tumor metastasis in vivo. However, overexpression of hsa_circ_0007919 exerted the opposite effects. Mechanistically, hsa_circ_0007919 could recruit the transcription factor Sp1 to inhibit THBS1 transcription, thereby facilitating PC metastasis. hsa_circ_0007919 can promote the metastasis of PC by inhibiting THBS1 expression. hsa_circ_0007919 may be a potential therapeutic target in PC.

Plasma THBS1 as a predictive biomarker for poor prognosis and brain metastasis in patients with HER2-enriched breast cancer

BACKGROUND

Thrombospondin-1 (THBS1) is a secretory adhesive glycoprotein involved in the progression of multiple malignancies, including breast cancer. However, the clinical significance and prognostic role of plasma THBS1 in breast cancer have yet to be clarified.

METHODS

Plasma THBS1 levels in 627 breast cancer patients were analyzed by enzyme-linked immunosorbent assay. Bone marrow blood was drawn from the anterior/posterior superior iliac spine to detect the presence of disseminated tumor cells (DTCs). The effects of plasma THBS1 on the clinicopathological characteristics and survival prediction of breast cancer patients were explored.

RESULTS

Plasma THBS1 did not correlate with overall survival, breast cancer-specific survival (BCSS), and distant disease-free survival (DDFS) in the entire breast cancer cohort. Notably, HER2-enriched patients with high-plasma THBS1 levels had significantly shorter BCSS (P = 0.027) and DDFS (P = 0.011) than those with low levels. Multivariate analyses revealed that plasma THBS1 was an independent prognostic marker of BCSS (P = 0.026) and DDFS (P = 0.007) in HER2-enriched patients. THBS1 levels were 24% higher in positive DTC patients than in negative DTC patients (P = 0.031), and high levels were significantly associated with poor BCSS in positive DTC patients (HR 2.08, 95% CI 1.17-3.71; P = 0.019). Moreover, high-plasma THBS1 levels were specifically associated with an increased occurrence of brain metastasis in HER2-enriched patients (P = 0.041).

CONCLUSION

These findings suggest that plasma THBS1 may be serving as an unfavorable prognosis predictor for HER2-enriched breast cancer and justifies the need for further research.

Pathophysiological roles of thrombospondin-4 in disease development

Thrombospondin-4 (TSP-4) belongs to the extracellular matrix glycoprotein family of thrombospondins (TSPs). The multidomain, pentameric structure of TSP-4 allows its interactions with numerous extracellular matrix components, proteins and signaling molecules that enable its modulation to various physiological and pathological processes. Characterization of TSP-4 expression under development and pathogenesis of disorders has yielded important insights into mechanisms underlying the unique role of TSP-4 in mediating various processes including cell-cell, cell-extracellular matrix interactions, cell migration, proliferation, tissue remodeling, angiogenesis, and synaptogenesis. Maladaptation of these processes in response to pathological insults and stress can accelerate the development of disorders including skeletal dysplasia, osteoporosis, degenerative joint disease, cardiovascular diseases, tumor progression/metastasis and neurological disorders. Overall, the diverse functions of TSP-4 suggest that it may be a potential marker or therapeutic target for prognosis, diagnosis, and treatment of various pathological conditions upon further investigations. This review article highlights recent findings on the role of TSP-4 in both physiological and pathological conditions with a focus on what sets it apart from other TSPs.

Thrombospondins in the tumor microenvironment

Many cancers begin with the formation of a small nest of transformed cells that can remain dormant for years. Thrombospondin-1 (TSP-1) initially promotes dormancy by suppressing angiogenesis, a key early step in tumor progression. Over time, increases in drivers of angiogenesis predominate, and vascular cells, immune cells, and fibroblasts are recruited to the tumor mass forming a complex tissue, designated the tumor microenvironment. Numerous factors, including growth factors, chemokine/cytokine, and extracellular matrix, participate in the desmoplastic response that in many ways mimics wound healing. Vascular and lymphatic endothelial cells, and cancer-associated pericytes, fibroblasts, macrophages and immune cells are recruited to the tumor microenvironment, where multiple members of the TSP gene family promote their proliferation, migration and invasion. The TSPs also affect the immune signature of tumor tissue and the phenotype of tumor-associated macrophages. Consistent with these observations, expression of some TSPs has been established to correlate with poor outcomes in specific types of cancer.

New insights into the role of thrombospondin-1 in glioblastoma development

Glioblastoma (GB), the most malignant subtype of diffuse glioma, is highly aggressive, invasive and vascularized. Its median survival is still short even with maximum standard care. There is a need to identify potential new molecules and mechanisms, that are involved in the interactions of GB cells with the tumor microenvironment (TME), for therapeutic intervention. Thrombospondin-1 (TSP1) is a multi-faceted matricellular protein which plays a significant role in development, physiology and pathology including cancer. Recent studies have pinpoint an important role of TSP1 in GB development which will be summarized and discussed herein. We will discuss studies, mainly from preclinical research, which should lead to a deeper understanding of TSP1's role in GB development. We will also discuss some issues with regard to the use of this knowledge for the clinic.

Alleviating hypoxia to improve cancer immunotherapy

Tumor hypoxia resulting from abnormal and dysfunctional tumor vascular network poses a substantial obstacle to immunotherapy. In fact, hypoxia creates an immunosuppressive tumor microenvironment (TME) through promoting angiogenesis, metabolic reprogramming, extracellular matrix remodeling, epithelial-mesenchymal transition (EMT), p53 inactivation, and immune evasion. Vascular normalization, a strategy aimed at restoring the structure and function of tumor blood vessels, has been shown to improve oxygen delivery and reverse hypoxia-induced signaling pathways, thus alleviates hypoxia and potentiates cancer immunotherapy. In this review, we discuss the mechanisms of tumor tissue hypoxia and its impacts on immune cells and cancer immunotherapy, as well as the approaches to induce tumor vascular normalization. We also summarize the evidence supporting the use of vascular normalization in combination with cancer immunotherapy, and highlight the challenges and future directions of this overlooked important field. By targeting the fundamental problem of tumor hypoxia, vascular normalization proposes a promising strategy to enhance the efficacy of cancer immunotherapy and improve clinical outcomes for cancer patients.

Invadopodia associated Thrombospondin-1 contributes to a post-therapy pro-invasive response in glioblastoma cells

A critical challenge in the treatment of glioblastoma (GBM) is its highly invasive nature which promotes cell migration throughout the brain and hinders surgical resection and effective drug delivery. GBM cells demonstrate augmented invasive capabilities following exposure to the current gold standard treatment of radiotherapy (RT) and concomitant and adjuvant temozolomide (TMZ), resulting in rapid disease recurrence. Elucidating the mechanisms employed by post-treatment invasive GBM cells is critical to the development of more effective therapies. In this study, we utilized a Nanostring® Cancer Progression gene expression panel to identify candidate genes that may be involved in enhanced GBM cell invasion after treatment with clinically relevant doses of RT/TMZ. Our findings identified thrombospondin-1 (THBS1) as a pro-invasive gene that is upregulated in these cells. Immunofluorescence staining revealed that THBS1 localised within functional matrix-degrading invadopodia that formed on the surface of GBM cells. Furthermore, overexpression of THBS1 resulted in enhanced GBM cell migration and secretion of MMP-2, which was reduced with silencing of THBS1. The preliminary data demonstrates that THBS1 is associated with invadopodia in GBM cells and is likely involved in the invadopodia-mediated invasive process in GBM cells exposed to RT/TMZ treatment. Therapeutic inhibition of THBS1-mediated invadopodia activity, which facilitates GBM cell invasion, should be further investigated as a treatment for GBM.

Cancer-specific association between Tau (MAPT) and cellular pathways, clinical outcome, and drug response

Tau (MAPT) is a microtubule-associated protein causing common neurodegenerative diseases or rare inherited frontotemporal lobar degenerations. Emerging evidence for non-canonical functions of Tau in DNA repair and P53 regulation suggests its involvement in cancer. To bring new evidence for a relevant role of Tau in cancer, we carried out an in-silico pan-cancer analysis of MAPT transcriptomic profile in over 10000 clinical samples from 32 cancer types and over 1300 pre-clinical samples from 28 cancer types provided by the TCGA and the DEPMAP datasets respectively. MAPT expression associated with key cancer hallmarks including inflammation, proliferation, and epithelial to mesenchymal transition, showing cancer-specific patterns. In some cancer types, MAPT functional networks were affected by P53 mutational status. We identified new associations of MAPT with clinical outcomes and drug response in a context-specific manner. Overall, our findings indicate that the MAPT gene is a potential major player in multiple types of cancer. Importantly, the impact of Tau on cancer seems to be heavily influenced by the specific cellular environment.

Transcriptomic characterization revealed that METTL7A inhibits melanoma progression via the p53 signaling pathway and immunomodulatory pathway

METTL7A is a protein-coding gene expected to be associated with methylation, and its expression disorder is associated with a range of diseases. However, few research have been carried out to explore the relationship between METTL7A and tumor malignant phenotype as well as the involvement potential mechanism. We conducted our research via a combination of silico analysis and molecular biology techniques to investigate the biological function of METTL7A in the progression of cancer. Gene expression and clinical information were extracted from the TCGA database to explore expression variation and prognostic value of METTL7A. In vitro, CCK8, transwell, wound healing and colony formation assays were conducted to explore the biological functions of METT7A in cancer cell. GSEA was performed to explore the signaling pathway involved in METTL7A and validated via western blotting. In conclusion, METTL7A was downregulated in most cancer tissues and its low expression was associated with shorter overall survival. In melanoma, METTL7A downregulation was associated with poorer clinical staging, lower levels of TIL infiltration, higher IC50 levels of chemotherapeutic agents, and poorer immunotherapy outcomes. QPCR results confirm that METTL7A is down-regulated in melanoma cells. Cell function assays showed that METTL7A knockdown promoted proliferation, invasion, migration and clone formation of melanoma cells. Mechanistic studies showed that METTL7A inhibits tumorigenicity through the p53 signaling pathway. Meanwhile, METTL7A is also a potential immune regulatory factor.

The covert symphony: cellular and molecular accomplices in breast cancer metastasis

Breast cancer has emerged as the most commonly diagnosed cancer and primary cause of cancer-related deaths among women worldwide. Although significant progress has been made in targeting the primary tumor, the effectiveness of systemic treatments to prevent metastasis remains limited. Metastatic disease continues to be the predominant factor leading to fatality in the majority of breast cancer patients. The existence of a prolonged latency period between initial treatment and eventual recurrence in certain patients indicates that tumors can both adapt to and interact with the systemic environment of the host, facilitating and sustaining the progression of the disease. In order to identify potential therapeutic interventions for metastasis, it will be crucial to gain a comprehensive framework surrounding the mechanisms driving the growth, survival, and spread of tumor cells, as well as their interaction with supporting cells of the microenvironment. This review aims to consolidate recent discoveries concerning critical aspects of breast cancer metastasis, encompassing the intricate network of cells, molecules, and physical factors that contribute to metastasis, as well as the molecular mechanisms governing cancer dormancy.

Tumor-Associated Macrophage Subsets: Shaping Polarization and Targeting

The tumor microenvironment (TME) is a critical regulator of tumor growth, progression, and metastasis. Among the innate immune cells recruited to the tumor site, macrophages are the most abundant cell population and are present at all stages of tumor progression. They undergo M1/M2 polarization in response to signals derived from TME. M1 macrophages suppress tumor growth, while their M2 counterparts exert pro-tumoral effects by promoting tumor growth, angiogenesis, metastasis, and resistance to current therapies. Several subsets of the M2 phenotype have been observed, often denoted as M2a, M2b, M2c, and M2d. These are induced by different stimuli and differ in phenotypes as well as functions. In this review, we discuss the key features of each M2 subset, their implications in cancers, and highlight the strategies that are being developed to harness TAMs for cancer treatment.

Deciphering the molecular mechanism of the THBS1 gene in the TNF signaling axis in glioma stem cells

Glioma stem cells (GSCs) are thought to be responsible for the initiation and progression of glioblastoma (GBM). GBM presents highly invasive growth with a very high recurrence rate, so it has become a clinical problem to be solved urgently. RNAseq demonstrates that thrombospondin 1 (THBS1) acts not only in the angiogenic core of glioma but also with a high degree of invasiveness and infiltration. Nevertheless, defects in the signaling pathway research lead to a poor prognosis in glioma patients. To investigate the relevant molecular mechanism and signal pathway of glioma stem cell behavior mediated by THBS1, U251 astroglioma cells and GSCs were taken as model cells for in vitro experiments. The biological effects of THBS1 on glioma proliferation, migration, and adhesion were evaluated using Cell Counting Kit-8(CCK8) assays, EdU incorporation assays, migration assays, Transwell assays, Western blotting, and RNAseq. We found that the knockout of the THBS1 gene by CRISPR/Cas9 promoted proliferation and migration in U251 cells and GSCs, as well as influencing cell cycle progression by regulating the TNF/MAPK/NF-κB and TGF-β/Smad signaling pathways. Moreover, U251 cells and GSCs showed different responses to THBS1 knockout, suggesting specific and potential targets for GSCs in signaling pathways mediated by THBS1.

Blocking CD47-SIRPα Signal Axis as Promising Immunotherapy in Ovarian Cancer

Among the three primary gynecological malignancies, ovarian cancer has the lowest incidence but the worst prognosis. Because of the poor prognosis of ovarian cancer patients treated with existing treatments, immunotherapy is emerging as a potentially ideal alternative to surgery, chemotherapy, and targeted therapy. Among immunotherapies, immune checkpoint inhibitors have been the most thoroughly studied, and many drugs have been successfully used in the clinic. CD47, a novel immune checkpoint, provides insights into ovarian cancer immunotherapy. This review highlights the mechanisms of tumor immune evasion via CD47-mediated inhibition of phagocytosis and provides a comprehensive insight into the progress of the relevant targeted agents in ovarian cancer.

Tumor Vasculature as an Emerging Pharmacological Target to Promote Anti-Tumor Immunity

Tumor vasculature abnormality creates a microenvironment that is not suitable for anti-tumor immune response and thereby induces resistance to immunotherapy. Remodeling of dysfunctional tumor blood vessels by anti-angiogenic approaches, known as vascular normalization, reshapes the tumor microenvironment toward an immune-favorable one and improves the effectiveness of immunotherapy. The tumor vasculature serves as a potential pharmacological target with the capacity of promoting an anti-tumor immune response. In this review, the molecular mechanisms involved in tumor vascular microenvironment-modulated immune reactions are summarized. In addition, the evidence of pre-clinical and clinical studies for the combined targeting of pro-angiogenic signaling and immune checkpoint molecules with therapeutic potential are highlighted. The heterogeneity of endothelial cells in tumors that regulate tissue-specific immune responses is also discussed. The crosstalk between tumor endothelial cells and immune cells in individual tissues is postulated to have a unique molecular signature and may be considered as a potential target for the development of new immunotherapeutic approaches.

Temporally and spatially regulated collagen XVIII isoforms are involved in ureteric tree development via the TSP1-like domain

Collagen XVIII (ColXVIII) is a component of the extracellular matrix implicated in embryogenesis and control of tissue homoeostasis. We now provide evidence that ColXVIII has a specific role in renal branching morphogenesis as observed in analyses of total and isoform-specific knockout embryos and mice. The expression of the short and the two longer isoforms differ temporally and spatially during renal development. The lack of ColXVIII or its specific isoforms lead to congenital defects in the 3D patterning of the ureteric tree where the short isoform plays a prominent role. Moreover, the ex vivo data suggests that ColXVIII is involved in the kidney epithelial tree patterning via its N-terminal domains, and especially the Thrombospondin-1-like domain common to all isoforms. This morphogenetic function likely involves integrins expressed in the ureteric epithelium. Altogether, the results point to an important role for ColXVIII in the matrix-integrin-mediated functions regulating renal development.

Role of non-coding RNA in immune microenvironment and anticancer therapy of gastric cancer

Gastric cancer remains one of the cancers with the highest mortality in the world; therefore, it is very important to investigate its pathogenesis to improve the prognosis of gastric cancer patients. Recently, noncoding RNAs have become a research hotspot in the field of oncology. These RNA molecules play complex roles in the regulation of tumor cells, immune cells, and the tumor microenvironment. Therefore, studying their ability to regulate the gastric cancer immune microenvironment will provide us with a better perspective to understand their potential role in anticancer therapy. In this review, we discuss the regulatory effects of several common noncoding RNAs on the immune microenvironment of gastric cancer and their prospects in anticancer therapy to provide some novel insight into the identification of valuable diagnostic markers and improving the prognosis of gastric cancer patients.

Transcriptomic responses to cytotoxic drug cisplatin in water flea Daphnia magna

Cytotoxic drugs have been recognized by the European Union as the potential threat in the aquatic environment. As a typical cytotoxic drug, effects of long-term exposure to cisplatin at the environmentally relevant concentrations on the crustacean health and its molecular mechanism remain undetermined. In this study, the growth and reproduction of Daphnia magna resulting from cisplatin exposure were initially assessed. While the phenotypes were not altered in 2 μg L^-1, 20 μg L^-1, and 200 μg L^-1 treatment groups, cisplatin at 500 µg L^-1 significantly reduced the offspring number to 8-13 neonates in each brood, which was lower than 13-27 neonates in the control group. In addition to the delay in the time of first pregnancy, the body length was decreased by approximate 12.13% at day 7. Meanwhile, all daphnids died after exposure to 500 µg L^-1 cisplatin for 17 days. Transcriptome profiling bioassays were performed for 10 days to explore the alternation at the molecular level. Briefly, 980 (257 up- and 723 down-regulated), 429 (182 up- and 247 down-regulated) and 1984 (616 up-regulated and 1368 down-regulated) genes were differentially expressed (adj p < 0.05) in low (2 μg L^-1), medium (200 μg L^-1) and high (500 μg L^-1) cisplatin treatment groups, respectively. Differentially expressed genes were primarily enriched in the digestion and absorption, nerve conduction, endocrine interference, and circulatory related pathways. Specifically, the down-regulated digestive secretion and nutrient absorption and neuronal conduction pathways may lead to insufficient energy supply involved in growth and reproduction, and hinder ovarian development and cell growth. Down-regulation of ovarian steroids and relaxin signaling pathways may be related to the reduction of offspring number and delayed pregnancy, and reduced body length of D. magna may attribute to the enrichment of insulin secretion pathway. In addition, the death of D. magna may result from the reduced expression of genes in cardiomyocyte contraction and apoptosome processes. Taken together, this study revealed the potential toxic mechanism of cisplatin in a model water flea.

A newly defined basement membrane-related gene signature for the prognosis of clear-cell renal cell carcinoma

Background: Basement membranes (BMs) are associated with cell polarity, differentiation, migration, and survival. Previous studies have shown that BMs play a key role in the progression of cancer, and thus could serve as potential targets for inhibiting the development of cancer. However, the association between basement membrane-related genes (BMRGs) and clear cell renal cell carcinoma (ccRCC) remains unclear. To address that gap, we constructed a novel risk signature utilizing BMRGs to explore the relationship between ccRCC and BMs.

Methods: We gathered transcriptome and clinical data from The Cancer Genome Atlas (TCGA) and randomly separated the data into training and test sets to look for new potential biomarkers and create a predictive signature of BMRGs for ccRCC. We applied univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analyses to establish the model. The risk signature was further verified and evaluated through principal component analysis (PCA), the Kaplan-Meier technique, and time-dependent receiver operating characteristics (ROC). A nomogram was constructed to predict the overall survival (OS). The possible biological pathways were investigated through functional enrichment analysis. In this study, we also determined tumor mutation burden (TMB) and performed immunological analysis and immunotherapeutic drug analysis between the high- and low-risk groups.

Results: We identified 33 differentially expressed genes and constructed a risk model of eight BMRGs, including COL4A4, FREM1, CSPG4, COL4A5, ITGB6, ADAMTS14, MMP17, and THBS4. The PCA analysis showed that the signature could distinguish the high- and low-risk groups well. The K-M and ROC analysis demonstrated that the model could predict the prognosis well from the areas under the curves (AUCs), which was 0.731. Moreover, the nomogram showed good predictability. Univariate and multivariate Cox regression analysis validated that the model results supported the hypothesis that BMRGs were independent risk factors for ccRCC. Furthermore, immune cell infiltration, immunological checkpoints, TMB, and the half-inhibitory concentration varied considerably between high- and low-risk groups.

Conclusion: Employing eight BMRGs to construct a risk model as a prognostic indicator of ccRCC could provide us with a potential progression trajectory as well as predictions of therapeutic response.

Identification of a neural development gene expression signature in colon cancer stem cells reveals a role for EGR2 in tumorigenesis

Recent evidence demonstrates that colon cancer stem cells (CSCs) can generate neurons that synapse with tumor innervating fibers required for tumorigenesis and disease progression. Greater understanding of the mechanisms that regulate CSC driven tumor neurogenesis may therefore lead to more effective treatments. RNA-sequencing analyses of ALDHPositive CSCs from colon cancer patient-derived organoids (PDOs) and xenografts (PDXs) showed CSCs to be enriched for neural development genes. Functional analyses of genes differentially expressed in CSCs from PDO and PDX models demonstrated the neural crest stem cell (NCSC) regulator EGR2 to be required for tumor growth and to control expression of homebox superfamily embryonic master transcriptional regulator HOX genes and the neural stem cell and master cell fate regulator SOX2. These data support CSCs as the source of tumor neurogenesis and suggest that targeting EGR2 may provide a therapeutic differentiation strategy to eliminate CSCs and block nervous system driven disease progression.

Diagnostic and Prognostic Roles of Thrombospondin-2 in Digestive System Cancers

Background

Cancers of digestive system have high case-fatality rate. It is important to find more appropriate methods in diagnosing and predicting gastrointestinal malignances. And thrombospondin-2 (TSP-2) was reported to have the functions, although results were not identical. So we performed this meta-analysis to clarify the significance of TSP-2 in this area.

Methods

PubMed, Embase, Web of Science, Cochrane Library, and Clinicaltrial.gov were searched for relevant studies. Data were extracted from these involved records. For the meta-analysis of diagnostic test, bivariate mixed effect model was used to estimate diagnostic accuracy. For prognosis part, HRs and their 95% CIs were pooled to compare the overall survival (OS) and disease-free survival (DFS) between patients with high TSP-2 and low TSP-2.

Results

Nine records were eligible for the analysis of diagnostic test. Pooled results were as follows: sensitivity 0.60 (0.52, 0.68), specificity 0.96 (0.91, 0.98), positive likelihood ratio (PLR) 15.4 (7.3, 32.2), negative likelihood ratio (NLR) 0.42 (0.34, 0.50), and diagnostic odds ratio (DOR) 37 (18, 76). While in prognosis part, 10 articles were included. Patients with increased TSP-2 had shorter OS (HR = 1.64, 95% CI = 1.21-2.22); however, no difference was found in DFS between TSP-2 high and low groups (HR = 1.44, 95% CI = 0.28-7.33).

Conclusions

TSP-2, as a diagnostic marker, has a high specificity but a moderate sensitivity. Meanwhile, it plays a role in predicting OS. Therefore, making TSP-2 a routine assay could be beneficial to high-risk individuals and patients with digestive malignances.

Thrombospondin-2 holds prognostic value and is associated with metastasis and the mismatch repair process in gastric cancer

BACKGROUND

This study aims to investigate thrombospondin 2 (TSP2) expression levels in gastric cancer (GC) and determine the relationship between TSP2 and clinical characteristics and prognosis.

METHODS

The online database Gene Expression Profile Interactive Analysis (GEPIA) was used to analyse TSP2 mRNA expression levels in GC. The Kaplan-Meier plotter prognostic analysis tool was used to evaluate the influence of TSP2 expression on clinical prognosis in GC patients. TSP2 expression levels were analysed in paraffin-embedded GC samples and adjacent normal tissues by immunohistochemistry. The relationship between the clinicopathological characteristics and prognosis of GC patients was assessed. Transwell experiments were used to evaluate the effect of TSP2 on HGC27 and AGS cell invasion and migration. The EdU experiment was used to detect the effect of transfection of TSP2 on cell proliferation, and the flow cytometry experiment was used to detect the effect of TSP2 on cell apoptosis and the cell growth cycle. Western blotting (Wb) technology was used to detect MMP, E-cadherin, N-cadherin, Vimentin, Snail, AKT, PI3K, and VEGF protein expression in HGC27 cells.

RESULTS

Compared with normal tissues, TSP2 mRNA expression in GC was significantly upregulated and was closely related to the clinical stage of GC. High TSP2 expression significantly affected the OS, FP and PPS of patients with GC. Among these patients, TSP2 expression levels did not affect the prognosis of patients with GC in the N0 subgroup but significantly affected the prognosis of patients with GC in the N (1 + 2 + 3) subgroup. TSP2 protein expression levels were significantly higher in GC tissue compared with normal tissues (P < 0.01). The overall survival (OS) and relapse-free survival (RFS) of patients with high TSP2 expression were lower than those of patients with low TSP2 expression. Cells transfected with the TSP2-silencing sequence exhibited increased apoptosis and inhibition of proliferation, migration and invasion. AKT and PI3K expression in cells was significantly downregulated (P < 0.01). AKT, PI3K and VEGF expression in cells transfected with the TSP2 silencing sequence was significantly reduced. Proliferation, migration, invasion ability, and TSP2 expression levels significantly correlated with mismatch repair genes, such as PMS2, MSH6, MSH2, and MLH1 (P < 0.05).

CONCLUSION

TSP2 expression is significantly increased in GC. TSP2 expression is closely related to metastasis and the mismatch repair process in GC patients and affects GC patient prognosis. The mechanism may involve regulating gastric cancer cell proliferation and migration by modulating the VEGF/PI3K/AKT signalling pathway. TSP2 is a potential marker and therapeutic target for the prognosis of GC patients.

Antibody microarray analysis of amniotic fluid proteomes in women with cervical insufficiency and short cervix, and their association with pregnancy latency length

Introduction

This study aimed to investigate amniotic fluid (AF) proteins that were differentially expressed between patients with cervical insufficiency (CI) and asymptomatic short cervix (SCX, ≤ 25 mm), and whether these proteins could be predictive of spontaneous preterm birth (SPTB) in these patients.

Method

This was a retrospective cohort study of 129 singleton pregnant women with CI (n = 80) or SCX (n = 49) at 17 to 26 weeks who underwent amniocentesis. An antibody microarray was used to perform comparative proteomic profiling of AF from matched CI (n = 20) and SCX (n = 20) pregnancies. In the total cohort, an ELISA validation study was performed for 15 candidate proteins of interest. Subgroup analyses of patients with CI and SCX were conducted to evaluate the association between the 15 proteins and SPTB at < 32 weeks of gestation.

Results

Eighty-six proteins showed intergroup differences. ELISA validation confirmed significantly higher levels of AF EN-RAGE, IL-8, lipocalin-2, MMP-9, S100A8/A9, thrombospondin-2, and TNFR2 in patients with CI than in those with SCX. Multivariable analysis showed that increased AF levels of EN-RAGE, S100A8/A9, and uPA were independently associated with SPTB at < 32 weeks in patients with CI; whereas in patients with SCX, high AF levels of APRIL, EN-RAGE, LBP, and TNFR2 were independently associated with SPTB at < 32 weeks.

Conclusions

Multiple AF proteins show altered expression in patients with CI compared with SCX controls. Moreover, several novel mediators involved in inflammation were identified as potential biomarkers for predicting SPTB after the diagnosis of CI and SCX. These results provide new insights into target-specific molecules for targeted therapies to prevent SPTB in patients with CI/SCX.

Cautions should be taken when using cell models for gastric cancer research

Gastric cancer (GC)-derived cell lines were generally used in basic cancer research and drug screening. However, it is always concerned about the difference between cultured cells and primary tumor by oncologists. To address this question, we compared differentially expressed genes (DEGs) in primary cancers, healthy tissues, and cell lines both in vitro and in silico. Seven reported genes with decreased expression in GCs by DNA methylation were analyzed in our cohort studies and experimentally validation. Selected datasets from TCGA (The Cancer Genome Atlas), CCLE (The Broad Institute Cancer Cell Line Encyclopedia), and GTEx (The Genotype-Tissue Expression project) were used to represent GCs, GC-derived cell lines, and healthy tissues respectively in the in silico analysis. Thirty gastric tissues together with six cell lines were used for validations. Unexpectedly, we experimentally found that reported cancer-related downregulated genes were only found in cancer cell lines but not in biopsies. The unchanged gene expressions in primary GCs were generally consistent with our cohort study, using information from cancerous (TCGA) and healthy tissues (GETx). Substantial differences were also found between DEGs of cancer tissues (TGCA)/ healthy tissues (GTEx) pair and cell lines (CCLE)/ healthy tissues (GTEx) pair, which confirmed the significant differences between primary cancer and cancer cell lines. Moreover, elevated expression of YWHAQ (14-3-3 δ) and THBS1 were observed in the GC biopsies, which might be potential biomarkers for GC diagnosis, considering the increased YWHAQ and THBS1 associated with poor survival rates in gastric cancer patients. In sum, it is suggested that cautions should be taken when using GC cell lines to study genes that show great differences between cell lines and tissues.

Addition of an Fc-IgG induces receptor clustering and increases the in vitro efficacy and in vivo anti-tumor properties of the thrombospondin-1 type I repeats (3TSR) in a mouse model of advanced stage ovarian cancer

OBJECTIVES

Tumor vasculature is structurally abnormal, with anatomical deformities, reduced pericyte coverage and low tissue perfusion. As a result of this vascular dysfunction, tumors are often hypoxic, which is associated with an aggressive tumor phenotype, and reduced delivery of therapeutic compounds to the tumor. We have previously shown that a peptide containing the thrombospondin-1 type I repeats (3TSR) specifically targets tumor vessels and induces vascular normalization in a mouse model of epithelial ovarian cancer (EOC). However, due to its small size, 3TSR is rapidly cleared from circulation. We now introduce a novel construct with the 3TSR peptide fused to the C-terminus of each of the two heavy chains of the Fc region of human IgG1 (Fc3TSR). We hypothesize that Fc3TSR will have greater anti-tumor activity in vitro and in vivo compared to the native compound.

METHODS

Fc3TSR was evaluated in vitro using proliferation and apoptosis assays to investigate differences in efficacy compared to native 3TSR. In light of the multivalency of Fc3TSR, we also investigate whether it induces greater clustering of its functional receptor, CD36. We also compare the compounds in vivo using an orthotopic, syngeneic mouse model of advanced stage EOC. The impact of the two compounds on changes to tumor vasculature morphology was also investigated.

RESULTS

Fc3TSR significantly decreased the viability and proliferative potential of EOC cells and endothelial cells in vitro compared to native 3TSR. High-resolution imaging followed by image correlation spectroscopy demonstrated enhanced clustering of the CD36 receptor in cells treated with Fc3TSR. This was associated with enhanced downstream signaling and greater in vitro and in vivo cellular responses. Fc3TSR induced greater vascular normalization and disease regression compared to native 3TSR in an orthotopic, syngeneic mouse model of advanced stage ovarian cancer.

CONCLUSION

The development of Fc3TSR which is greater in size, stable in circulation and enhances receptor activation compared to 3TSR, facilitates its translational potential as a therapy in the treatment of metastatic advanced stage ovarian cancer.

MicroRNA 1228 Mediates the Viability of High Glucose-Cultured Renal Tubule Cells through Targeting Thrombospondin 2 and PI3K/AKT Signaling Pathway

AIM

The present study aimed to elucidate the potential function of microRNA 1228 (miR-1228) on the high glucose (HG)-damaged human renal proximal tubule cells (HK-2) and the underlying mechanism.

METHODS

The datasets GSE47185 and GSE51674 were downloaded from the Gene Expression Omnibus database for mining differently expressed mRNAs and miRNAs, respectively. Bioinformatics online tools were applied to predict the binding sites between miR-1228 and thrombospondin 2 (THBS2), which was confirmed by dual-luciferase assay. Real-time quantitative polymerase chain reaction was used to detect the mRNA level of miR-1228/THBS2. Western blot was used to detect the protein level of THBS2 and the PI3K/AKT signaling pathway-associated markers. HK-2 cells were cultured in HG (30 mM) to mimic hyperglycemia. Cell counting kit 8 and flow cytometry assays were utilized to determine the cell proliferation and apoptosis.

RESULTS

The expression of THBS2 was significantly upregulated in diabetic nephropathy (DN) based on bioinformatics tools and identified as a direct target of miR-1228. miR-1228 was downregulated in DN and HG-damaged HK-2 cells. HG notably reduced HK-2 cell proliferation. This negative effect was attenuated by transfecting with an miR-1228 mimic and aggravated by transfecting with an miR-1228 inhibitor. However, under basal condition, there was no significant effect on the HK-2 cell proliferation among blank control, mimic, and inhibitor groups. Overexpression of THBS2 abolished the elevating effect of the miR-1228 mimic on the HG-damaged HK-2 cell proliferation, while restored the inhibitory effects of the miR-1228 mimic on the cell apoptosis. On the contrary, the suppressive effects on the proliferation and the enhancive effects on the apoptosis by silencing miR-1228 in HK-2 cells stimulated with HG can be weakened by recommendation of THBS2 small interference RNAs. Furthermore, we also found that HG significantly enhanced the phosphorylation levels of PI3K and AKT. In terms of overexpression and knockdown experiments, Western blot analysis further revealed that miR-1228 inhibited the activation of the PI3K/AKT signaling pathway in HG-damaged HK-2 cells by regulating THBS2.

CONCLUSION

The findings illustrated that miR-1228 improved survivability and inhibited apoptosis in HK-2 cells stimulated with HG partly by restraining the activation of the PI3K/AKT signaling pathway.

Targeting Ovarian Carcinoma with TSP-1:CD47 Antagonist TAX2 Activates Anti-Tumor Immunity

TAX2 peptide is a cyclic peptide that acts as an orthosteric antagonist for thrombospondin-1 (TSP-1) interaction with CD47. TAX2 was first described for its anti-angiogenic activities and showed anti-cancer efficacy in numerous preclinical models. Here, we aimed at providing an extensive molecular characterization of TAX2 mode of action, while evaluating its potential in ovarian cancer therapy. Multidisciplinary approaches were used to qualify a TAX2 drug candidate in terms of stability, solubility and potency. Then, efficacy studies, together with benchmark experiments, were performed in relevant mouse models of ovarian carcinoma. TAX2 peptide appears to be stable and soluble in clinically relevant solvents, while displaying a favorable safety profile. Moreover, clinical data mining allowed for the identification of TSP-1 as a relevant pharmacological target in ovarian cancer. In mice, TAX2 therapy inhibits ovarian tumor growth and metastatic dissemination, while activating anti-cancer adaptive immunity. Interestingly, TAX2 also synergizes when administered in combination with anti-PD-1 immune checkpoint inhibitiors. Altogether, our data expose TAX2 as an optimized candidate with advanced preclinical characterization. Using relevant syngeneic ovarian carcinoma models, we highlighted TAX2's ability to convert poorly immunogenic tumors into ones displaying effective anti-tumor T-cell immunity.

Upregulation of THBS1 is Related to Immunity and Chemotherapy Resistance in Gastric Cancer

Purpose

Thrombospondin 1 (THBS1) is an endogenous inhibitor of angiogenesis, but it also promotes tumor invasion, metastasis, and immune response in the tumor environment. Previous research has found that THBS1 is highly expressed in many tumors and has a negative correlation with tumor prognosis. However, research on the relationship between THBS1 and immune infiltration in GC is less well documented, and the objective of our study was to investigate the role of THBS1 expression in GC.

Patients and Methods

The expression of THBS1 in GC was analyzed by Oncomine, TIMER, TGCA, GEO and IHC staining. Analysis of the signaling pathways associated with THBS1 expression in GC uses GSEA. The relationship between THBS1 expression and immune infiltration was analyzed by the ESTIMATE algorithm, single-cell transcriptome analysis, TIMER2 database and CIBERSORT algorithm. Finally, the relationship between THBS1 expression and drug sensitivity was analyzed by the CellMiner database.

Results

THBS1 was overexpressed in GC and was associated with poor prognosis, and high THBS1 expression was an independent risk factor. GSEA results showed that high THBS1 expression in GC was associated with tumorigenesis, adhesion, and significant immune enrichment. THBS1 expression was most strongly correlated with tumor-associated macrophages (TAMs), M2 macrophages and cancer-associated fibroblast (CAFs) in GC. THBS1 expression positively correlates with most immune checkpoint members, suggesting that THBS1 may play an important role in the tumor microenvironment. THBS1 overexpression was negatively correlated with some drug sensitivities, such as Oxaliplatin.

Conclusion

Upregulation of THBS1 was positively correlated with poor prognosis and immunosuppression in GC and negatively correlated with anticancer drug sensitivity, suggesting that THBS1 may serve as a potential target for the treatment of GC.

Circulating methylated THBS1 DNAs as a novel marker for predicting peritoneal dissemination in gastric cancer

Objectives

Thrombospondin 1 (THBS1) is known to play a key role in tumor metastasis, and aberrant DNA methylation is one of the mechanisms regulating THBS1. The present study investigated whether methylated THBS1 in circulating cell‐free DNA from preoperative peritoneal lavage fluid (PPLF) and peripheral blood could be used as a potential biomarker for predicting peritoneal dissemination in gastric cancer (GC) patients.

Methods

The status of THBS1 methylation was detected by quantitative methylation‐specific PCR (MSP) in tumor tissues, paired PPLF, and serum from 92 GC patients. The correlation between methylated THBS1 levels and peritoneal dissemination of GC was studied, and its diagnostic value for predicting peritoneal dissemination was clarified by the receiver operating characteristic (ROC) curve.

Results

Aberrant THBS1 methylation in tumor tissues was significantly higher than that in paracancerous normal tissues (p < 0.0001). No THBS1 methylation was found in 40 healthy controls, and partial methylation was detected in 3 of 48 patients with chronic non‐atrophic gastritis. The frequency of THBS1 methylation in pairing PPLF and serum from 92 GC patients was 52.2% (48/92) and 58.7% (54/92), respectively. The results of methylated THBS1 in pairing PPLF and serum were similar to those of tumor tissues. Aberrant THBS1 methylation in tumor tissues and pairing PPLF or serum was closely related to peritoneal dissemination, tumor progression, and poor prognosis (all p < 0.0001).

Conclusion

Circulating methylated THBS1 DNAs in PPLF/serum may predict peritoneal dissemination, a potential poor prognostic factor for GC patients.

Panel biomarkers associated with cancer invasion and prognostic prediction for head-neck cancer

Aim: Cell invasion leading to metastasis is a major cause of treatment failure in head-neck cancers (HNCs). Identifying prognostic molecules associated with invasiveness is imperative for clinical applications. Materials & methods: A systemic approach was used to globally survey invasion-related genes, including transcriptomic profiling, pathway analysis, data mining and prognostic assessment using TCGA-HNSC dataset. Results: Six functional pathways and six hub molecules (LAMA3, LAMC2, THBS1, IGF1R, PDGFB and TGFβ1) were identified that significantly contributed to cell invasion, leading to poor survival in HNC patients. Combinations of multiple biomarkers substantially increased the probability of accurately predicting prognosis. Conclusion: Our six defined invasion-related molecules may be used as a panel signature in precision medicine for prognostic indicators or molecular therapeutic targets for HNC.

Thrombospondin-2 as a diagnostic biomarker for distal cholangiocarcinoma and pancreatic ductal adenocarcinoma

PURPOSE

Distal cholangiocarcinoma and pancreatic ductal adenocarcinoma are malignancies with poor prognoses that can be difficult to distinguish preoperatively. Thrombospondin-2 has been proposed as a novel diagnostic biomarker for early pancreatic ductal adenocarcinoma. The aim of the present study was to evaluate thrombospondin-2 as a diagnostic and prognostic biomarker in combination with current biomarker CA 19-9 for distal cholangiocarcinoma and pancreatic ductal adenocarcinoma.

METHODS

Thrombospondin-2 was measured in prospectively collected serum samples from patients who underwent surgery with a histopathological diagnosis of distal cholangiocarcinoma (N = 51), pancreatic ductal adenocarcinoma (N = 52) and benign pancreatic diseases (N = 27) as well as healthy blood donors (N = 52) using an enzyme-linked immunosorbent assay.

RESULTS

Thrombospondin-2 levels (ng/ml) were similar in distal cholangiocarcinoma 55 (41-77) and pancreatic ductal adenocarcinoma 48 (35-80) (P = 0.221). Thrombospondin-2 + CA 19-9 had an area under the curve of 0.92 (95% CI 0.88-0.97) in differentiating distal cholangiocarcinoma and pancreatic ductal adenocarcinoma from healthy donors which was superior to CA 19-9 alone (P < 0.001). The diagnostic value of adding thrombospondin-2 to CA 19-9 was larger in early disease stages. Thrombospondin-2 did not provide additional value to CA 19-9 in differentiating the benign disease group; however, heterogeneity was notable in the benign cohort. Three of five patients with autoimmune pancreatitis patients had greatly elevated thrombospondin-2 levels. Thrombospondin-2 levels had no correlation with prognoses.

CONCLUSIONS

Serum thrombospondin-2 in combination with CA 19-9 has potential as a biomarker for distal cholangiocarcinoma and pancreatic cancer.

Thrombospondin-4 promotes bladder cancer cell migration and invasion via MMP2 production

Bladder cancer (BC) is the second most common urological tumour in Western countries. Approximately, 80% of patients with BC will present with non-muscle invasive bladder cancer (NMIBC), whereas a quarter will have muscle invasive disease (MIBC) at the time of BC diagnosis. However, patients with NMIBC are at risk of BC recurrence or progression into MIBC, and an MIBC prognosis is determined by the presence of progression and metastasis. Matrix metalloproteinase 2 (MMP2), a type of matrix metalloproteinase (MMP), plays a major role in tumour invasion and is well-characterized in BC prognosis. In BC, the mechanisms regulating MMP2 expression, and, in turn, promote cancer invasion, have hardly been explored. Thrombospondin-4 (THBS4/TSP4) is a matricellular glycoprotein that regulates multiple biological functions, including proliferation, angiogenesis, cell adhesion and extracellular matrix modelling. Based on the results of a meta-analysis in the Gene Expression Profiling Interactive Analysis 2 database, we observed that TSP4 expression levels were consistent with overall survival (OS) rate and BC progression, with the highest expression levels observed in the advanced stages of BC and associated with poor OS rate. In our pilot experiments, incubation with recombinant TSP4 promoted the migration and invasion in BC cells. Furthermore, MMP2 expression levels increased after recombinant TSP4 incubation. TSP4-induced-MMP2 expression and cell motility were regulated via the AKT signalling pathway. Our findings facilitate further investigation into TSP4 silencing-based therapeutic strategies for BC.

Diagnostic, Therapeutic, and Prognostic Value of the Thrombospondin Family in Gastric Cancer

Background: Gastric cancer (GC) is the fifth leading cancer in the world. The dysregulated expressions of the thrombospondin (THBS) family were reported to associate with GC, but their relations with tumor stage, prognosis, and correlations with tumor immunity have not been systematically reported.

Methods: We used versatile public databases such as Oncomine, GEPIA, UALCAN, Kaplan–Meier Plotter, LinkedOmics, STRING, cBioPortal, TIMER, and TISIDB to analyze the expression and mutations of different THBSs in GC, along with their functional networks, survival analysis, and tumor–immune interactions.

Results: The mRNA levels of THBS2, THBS4, and COMP were significantly higher in the tumor tissues; the expression levels of THBS1, THBS2, and THBS4 were higher in stages 2–4 than that of stage 1; patients with high expression of THBS1, THBS2, THBS4, and COMP had poor OS; the genes correlated with THBSs were enriched in focal adhesion, glycosaminoglycan biosynthesis, ECM-receptor interaction, and hedgehog signaling pathway; THBS1 and THBS4 expression had significant correlations with tumor purity, and all the THBSs expression correlated with macrophage and dendritic cells infiltration.

Conclusions: THBS2, THBS4, and COMP were potentially diagnostic markers for GC; THBS1, THBS2, THBS4, and COMP were potentially prognostic markers for GC; investigating the relations of THBSs and tumor immunology might help in immunotherapy of GC, while more studies are needed to confirm these results.

Functions of Thrombospondin-1 in the Tumor Microenvironment

The identification of thrombospondin-1 as an angiogenesis inhibitor in 1990 prompted interest in its role in cancer biology and potential as a therapeutic target. Decreased thrombospondin-1 mRNA and protein expression are associated with progression in several cancers, while expression by nonmalignant cells in the tumor microenvironment and circulating levels in cancer patients can be elevated. THBS1 is not a tumor suppressor gene, but the regulation of its expression in malignant cells by oncogenes and tumor suppressor genes mediates some of their effects on carcinogenesis, tumor progression, and metastasis. In addition to regulating angiogenesis and perfusion of the tumor vasculature, thrombospondin-1 limits antitumor immunity by CD47-dependent regulation of innate and adaptive immune cells. Conversely, thrombospondin-1 is a component of particles released by immune cells that mediate tumor cell killing. Thrombospondin-1 differentially regulates the sensitivity of malignant and nonmalignant cells to genotoxic stress caused by radiotherapy and chemotherapy. The diverse activities of thrombospondin-1 to regulate autophagy, senescence, stem cell maintenance, extracellular vesicle function, and metabolic responses to ischemic and genotoxic stress are mediated by several cell surface receptors and by regulating the functions of several secreted proteins. This review highlights progress in understanding thrombospondin-1 functions in cancer and the challenges that remain in harnessing its therapeutic potential.

Chemotherapy-Enriched THBS2-Deficient Cancer Stem Cells Drive Hepatocarcinogenesis through Matrix Softness Induced Histone H3 Modifications

The physical microenvironment is a critical mediator of tumor behavior. However, detailed biological and mechanistic insight is lacking. The present study reveals the role of chemotherapy-enriched CD133+ liver cancer stem cells (CSCs) with THBS2 deficiency. This subpopulation of cells contributes to a more aggressive cancer and functional stemness phenotype in hepatocellular carcinoma (HCC) by remodeling the extracellular matrix (ECM) through the regulation of matrix metalloproteinase (MMP) activity, collagen degradation, and matrix stiffness. The local soft spots created by these liver CSCs can enhance stemness and drug resistance and provide a route of escape to facilitate HCC metastasis. Interestingly, a positive feed-forward loop is identified where a local soft spot microenvironment in the HCC tumor is enriched with CD133 expressing cells that secrete markedly less ECM-modifying THBS2 upon histone H3 modification at its promoter region, allowing the maintenance of a localized soft spot matrix. Clinically, THBS2 deficiency is also correlated with low HCC survival, where high levels of CSCs with low THBS2 expression in HCC are associated with decreased collagen fiber deposits and an invasive tumor front. The findings have implications for the treatment of cancer stemness and for the prevention of tumor outgrowth through disseminated tumor cells.

Deciphering microRNA-mRNA regulatory network in adult T-cell leukemia/lymphoma; the battle between oncogenes and anti-oncogenes

Adult T-cell leukemia/lymphoma (ATLL) is virus-caused cancer that originates from the infection by human T-cell leukemia virus type 1. ATLL dysregulates various biological pathways related to the viral infection and cancer progression through the dysexpression of miRNAs and mRNAs. In this study, the potential regulatory subnetworks were constructed aiming to shed light on the pathogenesis mechanism of ATLL. For this purpose, two mRNA and one miRNA expression datasets were firstly downloaded from the GEO database. Next, the differentially expressed genes and miRNAs (DEGs and DE-miRNAs, respectively), as well as differentially co-expressed gene pairs (DCGs), were determined. Afterward, common DEGs and DCGs targeted by experimentally validated DE-miRNAs were explored. The oncogenic and anti-oncogenic miRNA-mRNA regulatory subnetworks were then generated. The expression levels of four genes and two miRNAs were examined in the blood samples by qRT-PCR. The members of three oncogenic/anti-oncogenic subnetworks were generally enriched in immune, virus, and cancer-related pathways. Among them, FZD6, THBS4, SIRT1, CPNE3, miR-142-3p, and miR-451a were further validated by real-time PCR. The significant up-regulation of FZD6, THBS4, and miR-451a as well as down-regulation of CPNE3, SIRT1, and miR-142-3p were found in ATLL samples than normal samples. The identified oncogenic/anti-oncogenic subnetworks are pieces of the pathogenesis puzzle of ATLL. The ultimate winner is probably an oncogenic network that determines the final fate of the disease. The identified genes and miRNAs are proposed as novel prognostic biomarkers for ATLL.

Platelet TSP-1 controls prostate cancer-induced osteoclast differentiation and bone marrow-derived cell mobilization through TGFβ-1

The development of distant metastasis is the leading cause of prostate cancer (CaP)-related death, with the skeleton being the primary site of metastasis. While the progression of primary tumors and the growth of bone metastatic tumors are well described, the mechanisms controlling pre-metastatic niche formation and homing of CaP to bone remain unclear. Through prior studies, we demonstrated that platelet secretion was required for ongoing tumor growth and pre-metastatic tumor-induced bone formation. Platelets stimulated bone marrow-derived cell (BMDC) mobilization to tumors supporting angiogenesis. We hypothesized that proteins released by the platelet α granules were responsible for inducing changes in the pre-metastatic bone niche. We found that the classically anti-angiogenic protein thrombospondin (TSP)-1 was significantly increased in the platelets of mice with RM1 murine CaP tumors. To determine the role of increased TSP-1, we implanted tumors in TSP-1 null animals and assessed changes in tumor growth and pre-metastatic niche. TSP-1 loss resulted in increased tumor size and enhanced angiogenesis by immunohistochemistry. Conversely, TSP-1 deletion reduced BMDC mobilization and enhanced osteoclast formation resulting in decreased tumor-induced bone formation as measured by microcomputed tomography. We hypothesized that changes in the pre-metastatic niche were due to the retention of TGF-β1 in the platelets of mice after TSP-1 deletion. To assess the importance of platelet-derived TGF-β1, we implanted RM1 CaP tumors in mice with platelet factor 4-driven deletion of TGF-β1 in platelets and megakaryocytes. Like TSP-1 deletion, loss of platelet TGF-β1 resulted in increased angiogenesis with a milder effect on tumor size and BMDC release. Within the bone microenvironment, platelet TGF-β1 deletion prevented tumor-induced bone formation due to increased osteoclastogenesis. Thus, we demonstrate that the TSP-1/TGF-β1 axis regulates pre-metastatic niche formation and tumor-induced bone turnover. Targeting the platelet release of TSP-1 or TGF-β1 represents a potential method to interfere with the process of CaP metastasis to bone.

Proteome-wide and matrisome-specific alterations during human pancreas development and maturation

The extracellular matrix (ECM) is unique to each tissue and capable of guiding cell differentiation, migration, morphology, and function. The ECM proteome of different developmental stages has not been systematically studied in the human pancreas. In this study, we apply mass spectrometry-based quantitative proteomics strategies using N,N-dimethyl leucine isobaric tags to delineate proteome-wide and ECM-specific alterations in four age groups: fetal (18-20 weeks gestation), juvenile (5-16 years old), young adults (21-29 years old) and older adults (50-61 years old). We identify 3,523 proteins including 185 ECM proteins and quantify 117 of them. We detect previously unknown proteome and matrisome features during pancreas development and maturation. We also visualize specific ECM proteins of interest using immunofluorescent staining and investigate changes in ECM localization within islet or acinar compartments. This comprehensive proteomics analysis contributes to an improved understanding of the critical roles that ECM plays throughout human pancreas development and maturation.

Exploration of identifying novel serum biomarkers for malignant mesothelioma using iTRAQ combined with 2D-LC-MS/MS

Malignant mesothelioma (MM) is an aggressive cancer linked to asbestos exposure. Its poor prognosis makes early diagnosis extremely important, which would provide an opportunity for early treatment and potentially changing outcomes. This study aimed to explore the underlying mechanisms of MM and discover novel noninvasive biomarkers for the diagnosis of malignant mesothelioma. Using Isobaric tags for relative and absolute quantitation (iTRAQ) combined with two-dimensional liquid chromatography/tandem mass spectrometry (2D LC-MS/MS), a total of 145 differentially expressed serum proteins were identified between MM patients and healthy controls. The identified proteins were further analyzed by bioinformatics, out of which three candidate biomarkers (Filamin A (FLNA), Fibulin 1 (FBLN1) and Thrombospondin-1 (TSP-1)) were validated in large cohorts of patients with asbestos-related diseases including MM patients by ELISA assay. Receiver operating characteristic (ROC) curve analysis showed that serum FLNA, FBLN1 and TSP-1 had high diagnostic values in distinguishing MM patients from healthy controls, individuals with asbestos exposure (AE), and patients with pleural plaques (PP) or asbestosis. Meanwhile, serum FBLN1 and TSP-1 possessed good diagnostic values in distinguishing asbestosis patients from healthy controls and individuals with AE. The combination of FLNA, FBLN1, and TSP-1 proteins had higher sensitivity and specificity in discriminating patients with MM, PP and asbestosis. Our findings indicated that analysis of serum proteome using iTRAQ is a feasible strategy for biomarker discovery, and serum FLNA, FBLN1 and TSP-1 may be promising candidates for diagnosis of malignant mesothelioma and screening of at-risk individuals.

Tandem mass tag-based quantitative proteomic profiling of the serum of patients with abnormal uterine bleeding associated with copper intrauterine device

OBJECTIVE

To investigate changes in the level of protein in serum and uncover the underlying pathogenesis of abnormal uterine bleeding (AUB) associated with copper intrauterine devices (Cu IUD).

METHODS

Protein profiles were investigated via tandem mass tag (TMT)-based quantitative proteomics and bioinformatics technology. Quantification and characterization of candidate proteins were further performed in 33 controls and 45 cases by Luminex assay and enzyme-linked immunosorbent assay.

RESULTS

In total, 842 proteins were identified via TMT coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the serum of individuals with IUDs. Among them, 25 differentially expressed proteins (p < 0.05) were observed, including eight upregulated proteins and 17 downregulated proteins. Ten proteins were verified, and Alpha-1-Antitrypsin (a1AT) had a significantly elevated expression in women with AUB associated with the Cu IUD compared with healthy controls (p = 0.026) and a high area under the curve value (0.656), as well as sensitivity (64.9%) and specificity (71.9%).

CONCLUSION

This is the first study to explore changes in serum protein and the underlying mechanisms of AUB associated with the Cu IUD via TMT technology. a1AT with biomarker potential was validated. These findings might provide an experimental basis for the early diagnosis or treatment of AUB associated with the Cu IUD.

Thrombospondin-1 mimetics are promising novel therapeutics for MYC-associated medulloblastoma

BACKGROUND

Medulloblastoma (MB) comprises four subtypes of which group 3 MB are the most aggressive. Although overall survival for MB has improved, the outcome of group 3 MB remains dismal. C-MYC (MYC) amplification or MYC overexpression which characterizes group 3 MB is a strong negative prognostic factor and is frequently associated with metastases and relapses. We previously reported that MYC expression alone promotes highly aggressive MB phenotypes, in part via repression of thrombospondin-1 (TSP-1), a potent tumor suppressor.

METHODS

In this study, we examined the potential role of TSP-1 and TSP-1 peptidomimetic ABT-898 in MYC-amplified human MB cell lines and two distinct murine models of MYC-driven group 3 MBs.

RESULTS

We found that TSP-1 reconstitution diminished metastases and prolonged survival in orthotopic xenografts and promoted chemo- and radio-sensitivity via AKT signaling. Furthermore, we demonstrate that ABT-898 can recapitulate the effects of TSP-1 expression in MB cells in vitro and specifically induced apoptosis in murine group 3 MB tumor cells.

CONCLUSION

Our data underscore the importance of TSP-1 as a critical tumor suppressor in MB and highlight TSP-1 peptidomimetics as promising novel therapeutics for the most lethal subtype of MB.

Licochalcone A is a Natural Selective Inhibitor of Arginine Methyltransferase 6

Arginine methylation is a post-translational modification that is implicated in multiple biological functions including transcriptional regulation. The expression of protein arginine methyltransferases (PRMT) has been shown to be upregulated in various cancers. PRMTs have emerged as attractive targets for the development of new cancer therapies. Here, we describe the identification of a natural compound, licochalcone A, as a novel, reversible and selective inhibitor of PRMT6. Since expression of PRMT6 is upregulated in human breast cancers and is associated with oncogenesis, we used the human breast cancer cell line system to study the effect of licochalcone A treatment on PRMT6 activity, cell viability, cell cycle, and apoptosis. We demonstrated that licochalcone A is a non-S-adenosyl L-methionine (SAM) binding site competitive inhibitor of PRMT6. In MCF-7 cells, it inhibited PRMT6-dependent methylation of histone H3 at arginine 2 (H3R2), which resulted in a significant repression of estrogen receptor activity. Licochalcone A exhibited cytotoxicity towards human MCF-7 breast cancer cells, but not MCF-10A human breast epithelial cells, by upregulating p53 expression and blocking cell cycle progression at G2/M, followed by apoptosis. Thus, licochalcone A has potential for further development as a therapeutic agent against breast cancer.

Thrombospondin 2/Toll-Like Receptor 4 Axis Contributes to HIF-1α-Derived Glycolysis in Colorectal Cancer

Background

Aerobic glycolysis is a typical metabolic reprogramming in tumor cells, which contributes to the survival and proliferation of tumor cells. The underlying mechanisms controlling this metabolic switch in colorectal cancer (CRC), however, remain only partially understood.

Methods

The Cancer Genome Atlas (TCGA) dataset and Gene Expression Omnibus (GEO) (GDS4382, GSE6988, GSE35834) were used to analyzed the mRNA expression of THBS2. 392 paired samples of CRC and adjacent non-cancerous tissues were collected to detect the expression of THBS2 by IHC. The correlation of THBS2 expression with categorical clinical variables in patients with CRC was evaluated using chi-square analysis or Student's t-test. CCK-8, colony formation, and animal CT scan were used to functional analysis of THBS2 in CRC.

Results

Thrombospondin 2 (THBS2) is aberrantly upregulated and linked to a poor prognosis in CRC. Subsequent experiments also showed that THBS2 promotes the proliferation of CRC cells. In terms of mechanism, THBS2 interacted with Toll-like receptor 4 (TLR4), but not with the other toll-like receptors (TLRs), which upregulated the mRNA expression of GLUT1, HK2, ALDOA, PKM2, and LDHA and enhanced glycolytic capacity in CRC cells. Moreover, THBS2/TLR4 axis significantly increased the protein level of HIF-1α and blocking HIF-1α by siRNA reversed the enhanced glycolytic capacity and the upregulated expression of glycolytic enzymes in CRC cells.

Conclusion

Our findings revealed that the THBS2/TLR4 axis contributes to HIF-1α derived glycolysis and eventually promotes CRC progress.

Mass spectrometry-based analysis of formalin-fixed, paraffin-embedded distal cholangiocarcinoma identifies stromal thrombospondin-2 as a potential prognostic marker

Background

Distal cholangiocarcinoma is an aggressive malignancy with a dismal prognosis. Diagnostic and prognostic biomarkers for distal cholangiocarcinoma are lacking. The aim of the present study was to identify differentially expressed proteins between distal cholangiocarcinoma and normal bile duct samples.

Methods

A workflow utilizing discovery mass spectrometry and verification by parallel reaction monitoring was used to analyze surgically resected formalin-fixed, paraffin-embedded samples from distal cholangiocarcinoma patients and normal bile duct samples. Bioinformatic analysis was used for functional annotation and pathway analysis. Immunohistochemistry was performed to validate the expression of thrombospondin-2 and investigate its association with survival.

Results

In the discovery study, a total of 3057 proteins were identified. Eighty-seven proteins were found to be differentially expressed (q < 0.05 and fold change ≥ 2 or ≤ 0.5); 31 proteins were upregulated and 56 were downregulated in the distal cholangiocarcinoma samples compared to controls. Bioinformatic analysis revealed an abundance of differentially expressed proteins associated with the tumor reactive stroma. Parallel reaction monitoring verified 28 proteins as upregulated and 18 as downregulated in distal cholangiocarcinoma samples compared to controls. Immunohistochemical validation revealed thrombospondin-2 to be upregulated in distal cholangiocarcinoma epithelial and stromal compartments. In paired lymph node metastases samples, thrombospondin-2 expression was significantly lower; however, stromal thrombospondin-2 expression was still frequent (72%). Stromal thrombospondin-2 was an independent predictor of poor disease-free survival (HR 3.95, 95% CI 1.09–14.3; P = 0.037).

Conclusion

Several proteins without prior association with distal cholangiocarcinoma biology were identified and verified as differentially expressed between distal cholangiocarcinoma and normal bile duct samples. These proteins can be further evaluated to elucidate their biomarker potential and role in distal cholangiocarcinoma carcinogenesis. Stromal thrombospondin-2 is a potential prognostic marker in distal cholangiocarcinoma.

THBS4 silencing regulates the cancer stem cell-like properties in prostate cancer via blocking the PI3K/Akt pathway

BACKGROUND

Although thrombospondins 4 (THBS4) participates in controlling the biology of prostate cancer (PCa), the mechanism underlying this regulation remains unknown. Hence, this study aims to identify the regulatory effects of THBS4 on the PCa stem cell-like properties and the potential mechanism associated with the phosphatidylinositol 3'-kinase (PI3K)/protein kinase B (Akt) pathway.

METHODS

PCa stem cells were sorted and identified using flow cytometry and THBS4 expression in the identified PCa stem cells was measured using Western blot assay. THBS4 was overexpressed or silenced in PCa stem cells, following which, self-renewal, proliferation, cell cycle distribution, and apoptosis of PCa stem cells were assessed as well as tumorigenicity in vivo was evaluated. PI3K/Akt pathway inhibitor was applied to identify its involvement in the regulatory roles of THBS4 in PCa stem cells.

RESULTS

THBS4 was expressed at a higher level in PCa stem cells than in PCa cells. The overexpression of THBS4 promoted the self-renewal and proliferation, curbed the apoptosis of PCa stem cells, and enhanced the in vivo tumorigenicity, which was achieved by activating the PI3K/Akt pathway. On the contrary, short-hairpin RNA-mediated silencing of THBS4 exhibited suppressive effects on those cancer stem cell (CSC)-like properties and promotive effects on their apoptosis.

CONCLUSION

THBS4 silencing can impede the CSC-like properties in PCa via blockade of the PI3K/Akt pathway, which provides patients with PCa a new therapeutic target.

The Thyroid Tumor Microenvironment: Potential Targets for Therapeutic Intervention and Prognostication

Thyroid cancer is the most common endocrine malignancy and incidences are rising rapidly, in both pediatric and adult populations. Many thyroid tumors are successfully treated which results in low mortality rates, but there is often a significant morbidity associated with thyroid cancer treatments. For patients with tumors that are not successfully treated with surgical resection or radioactive iodine treatment, prognosis is dramatically reduced. Patients diagnosed with anaplastic thyroid cancer face a very grim prognosis with a median survival of 6 months post-diagnosis. There is a critical need to identify patients who are at greatest risk of developing persistent disease and progressing to poorly differentiated or anaplastic disease. Furthermore, development of treatments associated with less morbidity would represent a significant improvement for thyroid cancer survivors. It is well established the stromal cells and components of the tumor microenvironment can drive tumor progression and resistance to therapy. Here we review the current state of what is known regarding the thyroid tumor microenvironment and how these factors may contribute to thyroid tumor pathogenesis. Study of the tumor microenvironment within thyroid cancer is a relatively new field, and more studies are needed to dissect the complex and dynamic crosstalk between thyroid tumor cells and its tumor niche.

Thrombospondin-1 counteracts the p97 inhibitor CB-5083 in colon carcinoma cells

p97 has recently emerged as a therapeutic target for cancer due to its essential functions in protein homeostasis. CB-5083 is a first-in-class, potent and selective ATP-competitive p97 inhibitor that induces proteotoxic stress in cancer cells. Potential mechanisms regulating the sensitivity of cells to p97 inhibition remain poorly studied. Here, we demonstrate that Thrombospondin-1 (THBS1) is a CB-5083-upregulated gene that helps confer resistance of HCT116 cells to CB-5083. Our immunoblotting and immunofluorescence data showed that CB-5083 significantly increases the steady-state abundance of THBS1. Blockade of THBS1 induction sensitized cells to CB-5083-mediated growth inhibition. Suppression of THBS1 caused an increase of CB-5083-induced sub-G1 population and caspase 3/7 activity suggesting that its function is linked to the survival of cancer cells in response to p97 inhibition. Altogether our data provide new evidence that THBS1 is important for the susceptibility of cells to p97 inhibition.

Analytical performance of thrombospondin-1 and cathepsin D immunoassays part of a novel CE-IVD marked test as an aid in the diagnosis of prostate cancer

The Prostate Specific Antigen (PSA) test suffers from low specificity for the diagnosis of Prostate Cancer (PCa). We originally discovered two cancer-related proteins thrombospondin-1 (THBS1) and cathepsin D (CTSD) using a mass-spectrometry-based proteomics approach. The two serum proteins were shown to improve the diagnosis of high-grade PCa. Thus, we developed quantitative ELISAs for the determination of their concentration in human serum. Here we report their analytical performance in terms of limit of detection, specificity, precision, linearity and interferences, which were determined based on CLSI guidelines. Further, we investigated the influence of pre-analytical factors on concentration measurements. For this, blood from 4-6 donors was collected in different tubes and stored at room temperature for different times prior to centrifugation at different centrifugal forces and temperatures. Stability of THBS1 and CTSD under different storage temperatures was also evaluated. Our results show that the assays are specific, linear and sensitive enough to allow measurement of clinical samples. Precision in terms of repeatability and total within-laboratory coefficient of variation (CV) are 5.5% and 8.1% for THBS1 and 4.3% and 7.2% for CTSD, respectively. Relative laboratory-to-laboratory differences were -6.3% for THBS1 and -3% for CTSD. Both THBS1 and CTSD were stable in serum samples, with 80-120% recoveries of concentrations across donors, sample preparation and storage. In conclusion, the ELISAs as part of the novel commercial in vitro diagnostic test Proclarix are suitable for the use in clinical practice. THBS1 and CTSD can be accurately measured for their intended use independent of the lot and laboratory when conditions consistent with routine practice for PSA sampling and storage are used.

Non-coding RNAs in GI cancers: from cancer hallmarks to clinical utility

One of the most unexpected discoveries in molecular oncology, in the last decades, was the identification of a new layer of protein coding gene regulation by transcripts that do not codify for proteins, the non-coding RNAs. These represent a heterogeneous category of transcripts that interact with many types of genetic elements, including regulatory DNAs, coding and other non-coding transcripts and directly to proteins. The final outcome, in the malignant context, is the regulation of any of the cancer hallmarks. Non-coding RNAs represent the most abundant type of hormones that contribute significantly to cell-to cell communication, revealing a complex interplay between tumour cells, tumour microenvironment cells and immune cells. Consequently, profiling their abundance in bodily fluids became a mainstream of biomarker identification. Therapeutic targeting of non-coding RNAs represents a new option for clinicians that is currently under development. This review will present the biology and translational value of three of the most studied categories on non-coding RNAs, the microRNAs, the long non-coding RNAs and the circular RNAs. We will also focus on some aspirational concepts that can help in the development of clinical applications related to non-coding RNAs, including using pyknons to discover new non-coding RNAs, targeting human-specific transcripts which are expressed specifically in the tumour cell and using non-coding RNAs to increase the efficiency of immunotherapy.