MDM2 Derived from Dedifferentiated Liposarcoma Extracellular Vesicles Induces MMP2 Production from Preadipocytes.

Dedifferentiated liposarcoma (DDLPS) is frequently diagnosed late, and patients typically respond poorly to treatments. DDLPS is molecularly characterized by wild-type p53 and amplification of the MDM2 gene, which results in overexpression of MDM2 protein, a key oncogenic process in DDLPS. In this study, we demonstrate that extracellular vesicles derived from patients with DDLPS or from DDLPS cell lines are carriers of MDM2 DNA that can be transferred to preadipocytes, a major and ubiquitous cellular component of the DDLPS tumor microenvironment, leading to impaired p53 activity in preadipocytes and increased proliferation, migration, and production of matrix metalloproteinase 2; treatment with MDM2 inhibitors repressed these effects. Overall, these findings indicate that MDM2 plays a crucial role in DDLPS by enabling cross-talk between tumor cells and the surrounding microenvironment and that targeting vesicular MDM2 could represent a therapeutic option for treating DDLPS. SIGNIFICANCE: Extracellular vesicles derived from dedifferentiated liposarcoma cells induce oncogenic properties in preadipocytes.

Exosome-Derived miR-25-3p and miR-92a-3p Stimulate Liposarcoma Progression.

Despite the development of combined modality treatments against liposarcoma in recent years, a significant proportion of patients respond only modestly to such approaches, possibly contributing to local or distant recurrence. Early detection of recurrent or metastatic disease could improve patient prognosis by triggering earlier clinical intervention. However, useful biomarkers for such purposes are lacking. Using both patient plasma samples and cell lines, we demonstrate here that miR-25-3p and miR-92a-3p are secreted by liposarcoma cells through extracellular vesicles and may be useful as potential biomarkers of disease. Both miR-25-3p and miR-92a-3p stimulated secretion of proinflammatory cytokine IL6 from tumor-associated macrophages in a TLR7/8-dependent manner, which in turn promoted liposarcoma cell proliferation, invasion, and metastasis via this interaction with the surrounding microenvironment. Our findings provide novel and previously unreported insight into liposarcoma progression, identifying communication between liposarcoma cells and their microenvironment as a process critically involved in liposarcoma progression. This study establishes the possibility that the pattern of circulating miRNAs may identify recurrence prior to radiological detectability while providing insight into disease outcome and as a possible approach to monitor treatment efficacy. Cancer Res; 77(14); 3846-56. ©2017 AACR.

TGF-ß and CTGF are Mitogenic Output Mediators of Wnt/ß-Catenin Signaling in Desmoid Fibromatosis.

Desmoid fibromatosis is a locally aggressive clonal fibroblastic proliferation with high recurrence rates and no metastatic potential. Implicated molecular aberrations occur within the Wnt/ß-catenin pathway (APC and ß-catenin gene mutations). Transforming growth factor-ß (TGF-ß) and connective tissue growth factor (CTGF) are profibrotic growth factors, downstream from nuclear translocation of ß-catenin, that lead to increased fibrogenesis. CTGF (a downstream effector of TGF-ß) is a matricellular protein that modulates the activity of growth factors, adhesion molecules, integrins, and extracellular matrix thus playing a central role in tissue remodeling and fibrosis. Recently there has been growing interest in use of extracellular matrix inhibitors for treatment of various fibrogenic diseases. Desmoid fibromatosis samples (n=15) were evaluated for expression of ß-catenin, TGF-ß, and CTGF using immunohistochemistry on formalin paraffin-embedded material. A control group comprising scar tissue and adjacent normal skin (n=10) were simultaneously immunostained with above mentioned markers. Real-time polymerase chain reaction was performed on frozen specimens of desmoid fibromatosis (n=6) and normal skin (n=2). All 15 desmoid tumors were positive for ß-catenin (surrogate marker of Wnt/ß-catenin pathway dysregulation) which was negative in control normal skin and scar samples. TGF-ß and CTGF were negative in 9 of 10 normal skin controls. TGF-ß and CTGF were positive in all cases of scar tissue. All 15 cases of desmoid tumors were positive for TGF-ß and CTGF. The real-time polymerase chain reaction showed higher expression levels of TGF-ß and CTGF in desmoid fibromatosis compared with normal skin. The high constitutive expression of ß-catenin downstream effectors; TGF-ß, CTGF has the potential for enabling targeted therapy.