Inhibition of versican expression by siRNA facilitates tropoelastin synthesis and elastic fiber formation by human SK-LMS-1 leiomyosarcoma smooth muscle cells in vitro and in vivo

Abstract

Versican is an extracellular matrix (ECM) molecule that interacts with other ECM components to influence ECM organization, stability, composition, and cell behavior. Versican is known to increase in a number of cancers, but little is known about how versican influences the amount and organization of the ECM components in the tumor microenvironment. In the present study, we modulated versican expression using siRNAs in the human leiomyosarcoma (LMS) smooth muscle cell line SK-LMS-1, and observed the formation of elastin and elastic fibers in vitro and also in vivo in a nude mouse tumor model. Constitutive siRNA-directed knockdown of versican in LMS cells resulted in increased levels of elastin, as shown by immunohistochemical staining of the cells in vitro, and by mRNA and protein analyses. Moreover, versican siRNA LMS cells, when injected into nude mice, generated smaller tumors that had significantly greater immunohistochemical and histochemical staining for elastin when compared to control tumors. Additionally, microarray analyses were used to determine the influence of versican isoform modulation on gene expression profiles, and to identify genes that influence and relate to the process of elastogenesis. cDNA microarray analysis and TaqMan low density array validation identified previously unreported genes associated with downregulation of versican and increased elastogenesis. These results highlight an important role for the proteoglycan versican in regulating the expression and assembly of elastin and the phenotype of LMS cells.

Role of Thrombospondin-1 in Mechanotransduction and Development of Thoracic Aortic Aneurysm in Mouse and Humans

“…This is the first demonstration that a loss of Thbs1 improves the elastic fiber organization in the structurally compromised aortas. Second, it has previously been shown that inhibition of versican, which is a large extracellular matrix proteoglycan, promotes tropoelastin synthesis and elastic fiber formation in human leiomyosarcoma SMCs 48 . Since versican forms a functional complex with Thbs1 and is co-localized on microfibrils 49 , deletion of Thbs1 may have disrupted the inhibitory complex and facilitate elastic fiber formation in DKO aortas.…”

Provisional matrix: A role for versican and hyaluronan

“…Such a matrix that fails to transit to a more fibrous, cross-linked mature ECM could provide an environment for continued tumor growth, promoting tumor cell proliferation and migration [129]. In cancer, either the stromal cells surrounding the tumor or the tumor cells themselves produce hyaluronan/versican provisional matrices impacting tumor cell proliferation, migration, and metastasis [78, 123–125, 131]. For example, in a study of human leiomyosarcoma smooth muscle tumors which are enriched in versican, we found that the tumor cells exhibited thick pericellular coats in culture which could be reduced by inhibiting versican synthesis using siRNA treatment of these cells (Figure 5) [123].…”

The extracellular matrix molecules versican and hyaluronan in urethral and vaginal tissues in stress urinary incontinence

“…While collagen and elastin are the most abundant proteins in the ECM, proteoglycans play an important role in regulating the assembly, organization, and turnover of these proteins. The large chondroitin sulfate proteoglycan Vcan accumulates in tissues during inflammation and injury, where it interferes with elastic fiber assembly 7,8 and disrupts collagen remodeling 9,10 in a number of conditions including liver fibrosis, cancer, and chronic obstructive pulmonary disease. Furthermore, Vcan is emerging as a critical regulator of inflammation and has a major impact on tissue response to injury and disease 11,12 .…”