Abstract
BackgroundSarcomas are malignant heterogeneous tumors of mesenchymal derivation. Dedifferentiated liposarcoma (DDLPS) is aggressive with recurrence in 80% and metastasis in 20% of patients. We previously found that miR-133a was significantly underexpressed in liposarcoma tissues. As this miRNA has recently been shown to be a tumor suppressor in many cancers, the objective of this study was to characterize the biological and molecular consequences of miR-133a underexpression in DDLPS.MethodsReal-time PCR was used to evaluate expression levels of miR-133a in human DDLPS tissue, normal fat tissue, and human DDLPS cell lines. DDLPS cells were stably transduced with miR-133a vector to assess the effects in vitro on proliferation, cell cycle, cell death, migration, and metabolism. A Seahorse Bioanalyzer system was also used to assess metabolism in vivo by measuring glycolysis and oxidative phosphorylation (OXPHOS) in subcutaneous xenograft tumors from immunocompromised mice.ResultsmiR-133a expression was significantly decreased in human DDLPS tissue and cell lines. Enforced expression of miR-133a decreased cell proliferation, impacted cell cycle progression kinetics, decreased glycolysis, and increased OXPHOS. There was no significant effect on cell death or migration. Using an in vivo xenograft mouse study, we showed that tumors with increased miR-133a expression had no difference in tumor growth compared to control, but did exhibit an increase in OXPHOS metabolic respiration.ConclusionsBased on our collective findings, we propose that in DDPLS, loss of miR-133a induces a metabolic shift due to a reduction in oxidative metabolism favoring a Warburg effect in DDLPS tumors, but this regulation on metabolism was not sufficient to affect DDPLS.
Highlights
Sarcomas are malignant heterogeneous tumors of mesenchymal derivation
Results miR‐133a is underexpressed in Dedifferentiated liposarcoma (DDLPS) cell lines and liposarcoma tissues Previous results showed that miR-1, miR-133a, and miR206 were under expressed in paired liposarcoma tumor tissues compared to their adjacent normal tissues [12]
Consistent with these results, we observed that miR-1, miR-133a, and miR-206 were underexpressed in DDLPS cell lines 224B, 246, and 27 compared to control human preadipocyte cells (Fig. 1a–c)
Summary
Sarcomas are malignant heterogeneous tumors of mesenchymal derivation. Dedifferentiated liposarcoma (DDLPS) is aggressive with recurrence in 80% and metastasis in 20% of patients. We previously found that miR-133a was significantly underexpressed in liposarcoma tissues As this miRNA has recently been shown to be a tumor suppressor in many cancers, the objective of this study was to characterize the biological and molecular consequences of miR-133a underexpression in DDLPS. Our understanding of miRNAs in liposarcoma is limited, but several profiling studies led to the identification of candidate tumor suppressor and oncogenic miRNAs. Other studies have proposed that miR-25, miR-26a, miR-92a, miR-145, and miR-155 function as potential therapeutic targets for DDLPS management [7,8,9,10,11]. Other studies have proposed that miR-25, miR-26a, miR-92a, miR-145, and miR-155 function as potential therapeutic targets for DDLPS management [7,8,9,10,11] These data imply miRNAs might act as drivers in the pathogenesis of DDLPS
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