Syndecan-1 Overexpressing Mesothelioma Cells Inhibit Proliferation, Wound Healing, and Tube Formation of Endothelial Cells

Our plain-English summary of Syndecan-1 Overexpressing Mesothelioma Cells Inhibit Proliferation, Wound Healing, and Tube Formation of Endothelial Cells, by J. Javadi, G. Heidari-Hamedani, A. Schmalzl, et al (Cancers, 2021).

The study

• Authors: J. Javadi, G. Heidari-Hamedani, A. Schmalzl, T. Szatmári, M. Metintas, P. Aspenström, A. Hjerpe, K. Dobra
• Journal: Cancers
• Published: 2021;13(4)
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant mesothelioma (MM) is an aggressive tumor of the serosal cavities. Angiogenesis is important for mesothelioma progression, but so far, anti-angiogenic agents have not improved patient survival. Our hypothesis is that better understanding of the regulation of angiogenesis in this tumor would largely improve the success of such a therapy. Syndecan-1 (SDC-1) is a transmembrane heparan sulfate proteoglycan that acts as a co-receptor in various cellular processes including angiogenesis. In MM, the expression of SDC-1 is generally low but when present, SDC-1 associates to epithelioid differentiation, inhibition of tumor cell migration and favorable prognosis, meanwhile SDC-1 decrease deteriorates the prognosis. In the present study, we studied the effect of SDC-1 overexpression and silencing on MM cells ability to secrete angiogenic factors and monitored the downstream effect of SDC-1 modulation on endothelial cells proliferation, wound healing, and tube formation. This was done by adding conditioned medium from SDC-1 transfected and SDC-1 silenced mesothelioma cells to endothelial cells. Moreover, we investigated the interplay and molecular functional changes in angiogenesis in a co-culture system and characterized the soluble angiogenesis-related factors secreted to the conditioned media. We demonstrated that SDC-1 over-expression inhibited the proliferation, wound healing, and tube formation of endothelial cells. This effect was mediated by a multitude of angiogenic factors comprising angiopoietin-1 (Fold change ± SD: 0.65 ± 0.07), FGF-4 (1.45 ± 0.04), HGF (1.33 ± 0.07), NRG1-β1 (1.35 ± 0.08), TSP-1 (0.8 ± 0.02), TIMP-1 (0.89 ± 0.01) and TGF-β1 (1.35 ± 0.01). SDC-1 silencing increased IL8 (1.33 ± 0.06), promoted wound closure, but did not influence the tube formation of endothelial cells. Pleural effusions from mesothelioma patients showed that Vascular Endothelial Growth Factor (VEGF) levels correlate to soluble SDC-1 levels and have prognostic value. In conclusion, SDC-1 over-expression affects the angiogenic factor secretion of mesothelioma cells and thereby inhibits endothelial cells proliferation, tube formation, and wound healing. VEGF could be used in prognostic evaluation of mesothelioma patients together with SDC-1.

In plain English

This laboratory study, by researchers in Sweden and Turkey, examined a protein called syndecan-1 (SDC-1) in malignant mesothelioma. Asbestos exposure was not studied. The authors raised or lowered SDC-1 in one human mesothelioma cell line (STAV-AB). They then added fluid from those cells to human endothelial cells, the cells that line blood vessels, to study effects tied to blood vessel growth. With extra SDC-1, the mesothelioma cells released altered amounts of seven blood-vessel-related proteins. The endothelial cells exposed to this fluid grew less (cell numbers fell to 67.2% and 62.6% of controls at 24 and 48 hours), closed wounds more slowly and formed fewer tube-like structures. Lowering SDC-1 significantly sped wound closure but had no significant effect on tube formation. In pleural effusion fluid from mesothelioma patients, the growth factor VEGF correlated with soluble SDC-1 (r = 0.4; the text gives 39 samples, a figure legend 38 patients). Median survival was 6 months for 19 patients with higher VEGF and 14 months for 11 patients below 2.125 ng/mL. The authors concluded VEGF could be used with SDC-1 in prognostic evaluation. They noted that only one cell line was used.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (cell culture) study using one mesothelioma cell line and endothelial cells, plus measurements and survival analysis in stored pleural effusion samples from mesothelioma patients
• Who was studied: The human malignant mesothelioma cell line STAV-AB and human umbilical vein endothelial cells (HUVEC). Also 39 pleural effusions from malignant mesothelioma patients: 16 collected at Karolinska University Hospital, Huddinge, Sweden (2006 to 2012) and 23 collected at Eskisehir Osmangazi University, Turkey (2002 to 2004), all before treatment. The Figure 6 legend gives 38 patients for the correlation analysis. Survival times were available for a subset of patients.
• Exposure: Not asbestos. The variable studied was SDC-1 level in mesothelioma cells: overexpression by transfection with the full-length SDC-1 gene, or silencing with siRNA. Also silencing of MMP-7 to reduce SDC-1 shedding. In patients, VEGF and soluble SDC-1 levels in pleural effusions.
• Main results:
  • In fluid from SDC-1 overexpressing cells, seven angiogenesis-related proteins were significantly altered compared with control. Mean fold changes plus or minus SD were: angiopoietin-1 0.65 ± 0.07, FGF-4 1.45 ± 0.04, HGF 1.33 ± 0.12, NRG1-β1 1.35 ± 0.02, TIMP-1 0.89 ± 0.01, TSP-1 0.8 ± 0.04 and TGF-β1 1.35 ± 0.02.
  • SDC-1 silencing increased IL-8 (fold change 1.33 ± 0.06).
  • Endothelial (HUVEC) cell numbers fell to 67.2% and 62.6% of mock controls after 24 and 48 hours with fluid from SDC-1 overexpressing cells. The changes were statistically significant (p of 0.05 or less).
  • Wound closure by HUVEC cells was significantly lower with fluid from SDC-1 overexpressing cells (-11,541 pixel2/h versus -17,220 pixel2/hour for controls). It was significantly higher with fluid from SDC-1 silenced cells than with scrambled controls.
  • In the chemotaxis (directed movement) assay, the area covered by HUVEC cells was 12.48 ± 5% with fluid from SDC-1 overexpressing cells versus 8.45 ± 2.5% with mock control fluid. In the discussion, the authors state that chemotactic migration was not affected.
  • Tube formation with control fluid versus fluid from SDC-1 overexpressing cells (mean ± SEM): total tube length 12,706 ± 1359 pixel versus 6912 ± 678.1 pixel (p = 0.03); branching points 66.89 ± 13.89 versus 28.61 ± 6.528 (p = 0.05); loops 16.17 ± 1.049 versus 4.352 ± 1.591 (p = 0.009).
  • Fluid from SDC-1 silenced cells had no significant effect on tube formation by HUVEC cells.
  • MMP-7 silencing gave a 44 ± 6% knockdown of MMP-7 mRNA and decreased SDC-1 shedding by nearly 30%. Fluid from these cells did not affect any tube formation characteristic compared with scrambled control.
  • In pleural effusions from mesothelioma patients, VEGF and SDC-1 showed a significant fair correlation (r = 0.4; p less than 0.05). The results text gives n = 39, while the Figure 6 legend says 38 patients.
  • Median survival was 14 months for patients with effusion VEGF below 2.125 ng/mL (n = 11) and 6 months for patients with higher VEGF levels (n = 19). The hazard ratio was 2.83 (95% CI 1.26 to 6.37, p = 0.0083).
• The authors' conclusion: The authors concluded that SDC-1 overexpression changes growth factor secretion by mesothelioma cells in a way that inhibits endothelial cell proliferation, tube formation and migration. They also concluded that VEGF could be used in prognostic evaluation of mesothelioma patients, and suggested combining VEGF and shed SDC-1 measurements in pleural effusions.
• Limitations the authors state:
  • Only one mesothelioma cell line was used. Generalizing the findings to mesotheliomas in general requires study of additional cases, and the therapeutic and prognostic use remains to be evaluated.
  • A causal role for TGF-β1 in the inhibitory effects remains to be clarified.
  • Whether the effects come from lack of MMP-7 itself or from lack of both MMP-7 and shed SDC-1 was not tested.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Angiogenesis, Epithelioid, Prognosis, Pleural Effusion.

Related studies

• Novel genes and pathways modulated by syndecan-1: implications for the proliferation and cell-cycle regulation of malignant mesothelioma cells — T. Szatmári, F. Mundt, et al. (2012)
• In Silico Transcriptomic Analysis of Wound-Healing-Associated Genes in Malignant Pleural Mesothelioma — E. Rouka, E. Beltsios, et al. (2019)
• Effect of syndecan-1 overexpression on mesenchymal tumour cell proliferation with focus on different functional domains — F. Zong, E. Fthenou, et al. (2010)
• Syndecan-1 alters heparan sulfate composition and signaling pathways in malignant mesothelioma — G. Heidari-Hamedani, R.R. Vivès, et al. (2015)
• Diagnostic and prognostic value of soluble syndecan-1 in pleural malignancies — F. Mundt, G. Heidari-Hamedani, et al. (2014)
• Mapping the Interactome of the Nuclear Heparan Sulfate Proteoglycan Syndecan-1 in Mesothelioma Cells — A. Kumar-Singh, J. Shrinet, et al. (2020)

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