Identification of new genes associated to senescent and tumorigenic phenotypes in mesenchymal stem cells

Abstract

Although human mesenchymal stem cells (hMSCs) are a powerful tool for cell therapy, prolonged culture times result in replicative senescence or acquisition of tumorigenic features. To identify a molecular signature for senescence, we compared the transcriptome of senescent and young hMSCs with normal karyotype (hMSCs/n) and with a constitutional inversion of chromosome 3 (hMSC/inv). Senescent and young cells from both lineages showed differentially expressed genes (DEGs), with higher levels in senescent hMSCs/inv. Among the 30 DEGs in senescent hMSC/inv, 11 are new candidates for biomarkers of cellular senescence. The functional categories most represented in senescent hMSCs were related to cellular development, cell growth/proliferation, cell death, cell signaling/interaction, and cell movement. Mapping of DEGs onto biological networks revealed matrix metalloproteinase-1, thrombospondin 1, and epidermal growth factor acting as topological bottlenecks. In the comparison between senescent hMSCs/n and senescent hMSCs/inv, other functional annotations such as segregation of chromosomes, mitotic spindle formation, and mitosis and proliferation of tumor lines were most represented. We found that many genes categorized into functional annotations related to tumors in both comparisons, with relation to tumors being highest in senescent hMSCs/inv. The data presented here improves our understanding of the molecular mechanisms underlying the onset of cellular senescence as well as tumorigenesis.

Serial Xenotransplantation in NSG Mice Promotes a Hybrid Epithelial/Mesenchymal Gene Expression Signature and Stemness in Rhabdomyosarcoma Cells

“…Importantly, SOX4 is highly expressed in embryonal rhabdomyosarcoma compared with normal muscle and knockdown of SOX4 leads to a significant decrease in MYOD1 levels and impaired rhabdomyosarcoma cell survival [47]. Conversely, we have identified downregulation of MIR29A and MIR145 genes encoding microRNAs that are crucial for induction of myogenic differentiation [48] and repression of pluripotency [8,25], respectively. Although downregulation of microRNA 145 (miR-145) has been suggested in tumorigenesis of Ewing's sarcoma [8,49], our study provides the first evidence that miR-145 might be involved in regulation of CSC phenotype in rhabdomyosarcoma.…”

“…Thus, upregulated expression of PAX3 might explain the increased stemness of LTB24 rhabdomyosarcoma cells in our study. The gradual increase in rhabdomyosarcoma stemness could be further substantiated by the detected downregulation of 10 out of 18 genes that are associated with mesenchymal stem cell senescence [25] and by the upregulation of genes involved in early mesenchymal development and maintenance of myogenic precursors, i.e., SOX4 [45,46] and PITX2 [23]. SOX4 has been previously demonstrated to contribute to tumor progression by promoting cancer stemness [46].…”

“…In addition to the upregulation of SOX4 and EYA1, we identified the downregulation of two microRNA genes, MIR29A and a well-known stemness inhibitor MIR145 [8,24] (Figure 6b). Further analysis of 18 genes that correlate with mesenchymal stem cell senescence [25] revealed a remarkably significant downregulation of 10 genes (ANKRD1, KRT34, KRT19, SERPINB2, KRTAP1-5, LOC730755, PLCB4, THBS1, OXTR, MRVI1), while none of the analyzed genes was significantly upregulated during serial xenotransplantation (Figure 6c). Overall, these results clearly suggest that serial xenotransplantation in NSG mice selected for rhabdomyosarcoma cells (presumably CSCs), which acquire an expression signature of primitive undifferentiated cells that resemble non-senescent myogenic precursors/mesenchymal stem cells.…”

Autofluorescence-based sorting removes senescent cells from mesenchymal stromal cell cultures

“…6c). Of the 68 DEG, 16 genes (ITGB8, COL13A1, DUSP4, MYCT1, ESM1, FMO2, FMO3, NDNF, C1R, ESM1, CXCL12, VCAM1, NTN4, PLAT, KRT34, SERPINB2) have been already associate to senescence in MSC in vitro [25][26][27][28] and in vivo 29,30 .…”

“…Next, we investigated in all three MSC donors the expression of the genes CXCL12 26 (Fig. 8b), FGFR2 28 ( Fig.…”