Fibulin-3 Has Anti-Tumorigenic Activities in Cutaneous Squamous Cell Carcinoma

Matricellular proteins: Potential biomarkers in head and neck cancer

The extracellular matrix (ECM) is a complex network of diverse multidomain macromolecules, including collagen, proteoglycans, and fibronectin, that significantly contribute to the mechanical properties of tissues. Matricellular proteins (MCPs), as a family of non-structural proteins, play a crucial role in regulating various ECM functions. They exert their biological effects by interacting with matrix proteins, cell surface receptors, cytokines, and proteases. These interactions govern essential cellular processes such as differentiation, proliferation, adhesion, migration as well as multiple signal transduction pathways. Consequently, MCPs are pivotal in maintaining tissue homeostasis while orchestrating intricate molecular mechanisms within the ECM framework. The expression level of MCPs in adult steady-state tissues is significantly low; however, under pathological conditions such as inflammation and cancer, there is a substantial increase in their expression. In recent years, an increasing number of studies have focused on elucidating the role and significance of MCPs in the development and progression of head and neck cancer (HNC). During HNC progression, there is a remarkable upregulation in MCP expression. Through their distinctive structure and function, they actively promote tumor growth, invasion, epithelial-mesenchymal transition, and lymphatic metastasis of HNC cells. Moreover, by binding to integrins and modulating various signaling pathways, they effectively execute their biological functions. Furthermore, MCPs also hold potential as prognostic indicators. Although the star proteins of various MCPs have been extensively investigated, there remains a plethora of MCP family members that necessitate further scrutiny. This article comprehensively examines the functionalities of each MCP and highlights the research advancements in the context of HNC, with an aim to identify novel biomarkers for HNC and propose promising avenues for future investigations.

Extracellular matrix remodeling in tumor progression and immune escape: from mechanisms to treatments

The malignant tumor is a multi-etiological, systemic and complex disease characterized by uncontrolled cell proliferation and distant metastasis. Anticancer treatments including adjuvant therapies and targeted therapies are effective in eliminating cancer cells but in a limited number of patients. Increasing evidence suggests that the extracellular matrix (ECM) plays an important role in tumor development through changes in macromolecule components, degradation enzymes and stiffness. These variations are under the control of cellular components in tumor tissue via the aberrant activation of signaling pathways, the interaction of the ECM components to multiple surface receptors, and mechanical impact. Additionally, the ECM shaped by cancer regulates immune cells which results in an immune suppressive microenvironment and hinders the efficacy of immunotherapies. Thus, the ECM acts as a barrier to protect cancer from treatments and supports tumor progression. Nevertheless, the profound regulatory network of the ECM remodeling hampers the design of individualized antitumor treatment. Here, we elaborate on the composition of the malignant ECM, and discuss the specific mechanisms of the ECM remodeling. Precisely, we highlight the impact of the ECM remodeling on tumor development, including proliferation, anoikis, metastasis, angiogenesis, lymphangiogenesis, and immune escape. Finally, we emphasize ECM "normalization" as a potential strategy for anti-malignant treatment.

Fibulin-3 sponges Tiam1 to manipulate MMP-7 activity through β-catenin signaling in oral squamous cell carcinoma

Oral squamous cell carcinoma (named OSCC) is considered the most frequent malignancy in oral cavity, which has become a rapid increasing problem for the global public health with unclear molecular mechanism. Previously, Tiam1 (T-lymphoma invasion and metastasis inducing factor 1) has been reported as a potential oncogene for OSCC. Here, we in-depth explored its signaling mechanism for the disorder. The mRNA and protein expression levels of primary differentially expressed genes (Tiam1, Fibulin-3, and MMP-7) were measured in different TNM stages of OSCC patients using RT-PCR and ELISA methods. Based on the analysis of human OSCC cell line CAL27, the relationships between these factors have been further investigated and the interactions were also examined. The luciferase reporter assay was established for the promoter region of MMP-7. Both the epithelial (E-cadherin) and mesenchymal protein markers (Vimentin and Snail) expressions were examined using western blotting. The mRNA and protein activities of Fibulin-3 declined as the increase of TNM stage. Inversely, the mRNA and protein levels of Tiam1 and MMP-7 elevated significantly as OSCC progressed. Tiam1 transfection in CAL27 cells stimulated the expression of MMP-7 by accelerating the nuclear translocation of β-catenin, which was opposite to the functions of Fibulin-3. Moreover, Tiam1 interacted directly with Fibulin-3. The Tiam1 induced OSCC epithelial-mesenchymal transition (EMT) via MMP-7 activation, which was dependent on the direct binding of β-catenin at the promoter region. Collectively, these results indicated that Tiam1 competed with Fibulin-3 for nuclear β-catenin translocation, which subsequently stimulated MMP-7 expression by TCF-4 domain interaction following EMT initiation in OSCC development. Our systematical work hypothesized an innovative signaling cassette for OSCC progression, which provided beneficial references for future clinical study.

Fibulin-3 Deficiency Protects Against Myocardial Injury Following Ischaemia/ Reperfusion in in vitro Cardiac Spheroids

Myocardial infarction (MI, or heart attack) is a leading cause of death worldwide. Myocardial ischaemia reperfusion (I/R) injury typical of MI events is also associated with the development of cardiac fibrosis and heart failure in patients. Fibulin-3 is an extracellular matrix component that plays a role in regulating MI response in the heart. In this study, we generated and compared in vitro cardiac spheroids (CSs) from wild type (WT) and fibulin-3 knockout (Fib-3 KO) mice. These were then exposed to pathophysiological changes in oxygen (O₂) concentrations to mimic an MI event. We finally measured changes in contractile function, cell death, and mRNA expression levels of cardiovascular disease genes between WT and Fib-3 KO CSs. Our results demonstrated that there are significant differences in growth kinetics and endothelial network formation between WT and Fib-3 KO CSs, however, they respond similarly to changes in O₂ concentrations. Fib-3 deficiency resulted in an increase in viability of cells and improvement in contraction frequency and fractional shortening compared to WT I/R CSs. Gene expression analyses demonstrated that Fib-3 deficiency inhibits I/R injury and cardiac fibrosis and promotes angiogenesis in CSs. Altogether, our findings suggest that Fib-3 deficiency makes CSs resistant to I/R injury and associated cardiac fibrosis and helps to improve the vascular network in CSs.

LPCAT1 Promotes Cutaneous Squamous Cell Carcinoma via EGFR-Mediated Protein Kinase B/p38MAPK Signaling Pathways

Cutaneous squamous cell carcinoma (cSCC) is the second most common form of skin cancer. LPCAT1, a lysophosphatidylcholine acyltransferase, takes a center stage in membrane lipid remodeling. LPCAT1 is elevated in several cancers and contributes to cancer development. However, its role and molecular mechanisms in cSCC remain to be elucidated. In this study, we found that LPCAT1 was upregulated in cSCC tissues and in cell lines. In vitro, loss-of-function and gain-of-function experiments demonstrated that LPCAT1 facilitated cSCC cell proliferation, protected cells against apoptosis, accelerated epithelial‒mesenchymal transition, and enhanced cell metastasis. Mechanistically, LPCAT1 regulated EGFR signaling. The oncogenic effect of LPCAT1 was mediated by EGFR/protein kinase B and EGFR/p38MAPK pathways in cSCC. Using the xenograft mouse model, we consolidated the results mentioned earlier. In conclusion, LPCAT1 contributed to cSCC progression through EGFR-mediated protein kinase B and p38MAPK signaling pathways. LPCAT1 may serve as a target for therapeutic intervention in cSCC.

Overexpression of fibulin-3 in tumor tissue predicts poor survival of malignant mesothelioma patients from hand-spinning asbestos exposed area in eastern China

Fibulin-3 is an extracellular matrix glycoprotein widely expressed in various tissues. Tissue fibulin-3 expression have never been reported in association with prognosis of mesothelioma. Hence, we sought to determine the association between fibulin-3 expression and mesothelioma survival. We made a tissue microarray, which was comprised of cancer and normal tissue from mesothelioma patients (n = 82) during the period 1998-2017 in China. Fibulin-3 and HGMB1 expression were analyzed by immunohistochemistry method. Kaplan-Meier method and Cox proportional hazard models were used for analyzing survival data. Overall, 61 cases (74.4%) were female; 90.2% were of epithelioid type; the median overall survival time was 12.5 months. Fibulin-3 and HMGB1 were highly expressed in tumor tissue rather than adjacent tissue. The expression of fibulin-3 in tissue was correlated with that of HMGB1 (r = 0.32, P = 0.003). High expression of fibulin-3 in tumor tissue could predict poor survival in patients with mesothelioma (P = 0.02). This remained true in a multivariate model, with a significant hazard ratio of 1.91. We demonstrated that fibulin-3 in tumor tissue was a novel biomarker of poor survival of mesothelioma, suggesting it may be a relevant target for therapeutic intervention.