Accumulating evidence suggests that cancer-associated mesenchymal stem cells (MSC) contribute to the development and metastasis of hepatocellular carcinoma (HCC). Aberrant expression of long noncoding RNAs (lncRNA) has been associated with these processes but cellular mechanisms are obscure. In this study, we report that HCC-associated mesenchymal stem cells (HCC-MSC) promote epithelial–mesenchymal transition (EMT) and liver tumorigenesis. We identified a novel lncRNA that we termed lncRNA–MUF (MSC-upregulated factor) that is highly expressed in HCC tissues and correlated with poor prognosis. Depleting lncRNA–MUF in HCC cells repressed EMT and inhibited their tumorigenic potential. Conversely, lncRNA–MUF overexpression accelerated EMT and malignant capacity. Mechanistic investigations showed that lncRNA–MUF bound Annexin A2 (ANXA2) and activated Wnt/β-catenin signaling and EMT. Furthermore, lncRNA-MUF acted as a competing endogenous RNA for miR-34a, leading to Snail1 upregulation and EMT activation. Collectively, our findings establish a lncRNA-mediated process in MSC that facilitates hepatocarcinogenesis, with potential implications for therapeutic targeting. Cancer Res; 77(23); 6704–16. ©2017 AACR.

Cancer-associated mesenchymal stem cells (MSCs) play a pivotal role in modulating tumor progression. However, the interactions between liver cancer-associated MSCs (LC-MSCs) and hepatocellular carcinoma (HCC) remain unreported. Here, we identified the presence of MSCs in HCC tissues. We also showed that LC-MSCs significantly enhanced tumor growth in vivo and promoted tumor sphere formation in vitro . LC-MSCs also promoted HCC metastasis in an orthotopic liver transplantation model. Complementary DNA (cDNA) microarray analysis showed that S100A4 expression was significantly higher in LC-MSCs compared with liver normal MSCs (LN-MSCs) from adjacent cancer-free tissues. Importantly, the inhibition of S100A4 led to a reduction of proliferation and invasion of HCC cells, while exogenous S100A4 expression in HCC cells resulted in heavier tumors and more metastasis sites. Our results indicate that S100A4 secreted from LC-MSCs can promote HCC cell proliferation and invasion. We then found the expression of oncogenic microRNA (miR)-155 in HCC cells was significantly up-regulated by coculture with LC-MSCs and by S100A4 ectopic overexpression. The invasion-promoting effects of S100A4 were significantly attenuated by a miR-155 inhibitor. These results suggest that S100A4 exerts its effects through the regulation of miR-155 expression in HCC cells. We demonstrate that S100A4 secreted from LC-MSCs promotes the expression of miR-155, which mediates the down-regulation of suppressor of cytokine signaling 1, leading to the subsequent activation of STAT3 signaling. This promotes the expression of matrix metalloproteinases 9, which results in increased tumor invasiveness. Conclusion: S100A4 secreted from LC-MSCs is involved in the modulation of HCC progression, and may be a potential therapeutic target.

Cervical squamous cell carcinoma (CESC) is a prototypical human cancer with well-characterized pathological stages of initiation and progression. However, high-resolution knowledge of the transcriptional programs underlying each stage of CESC is lacking, and important questions remain. We performed single-cell RNA sequencing of 76,911 individual cells from 13 samples of human cervical tissues at various stages of malignancy, illuminating the transcriptional tumorigenic trajectory of cervical epithelial cells and revealing key factors involved in CESC initiation and progression. In addition, we found significant correlations between the abundance of specific myeloid, lymphoid, and endothelial cell populations and the progression of CESC, which were also associated with patients’ prognosis. Last, we demonstrated the tumor-promoting function of matrix cancer–associated fibroblasts via the NRG1-ERBB3 pathway in CESC. This study provides a valuable resource and deeper insights into CESC initiation and progression, which is helpful in refining CESC diagnosis and for the design of optimal treatment strategies.

Up to now, the gingiva-derived mesenchymal stem cells (GMSCs) as a new postnatal stem cells have been isolated and characterized with multipotential differentiation capabilities in vitro. However, the in vivo efficacy of utilizing the GMSCs in bone regeneration remains obscure. First of all, we identified canonical MSCs in human gingival tissue, which possessed homogenous immunophenotype (CD34⁻CD45⁻CD29⁺CD105⁺CD90⁺ STRO-1⁺) and had tri-lineage differentiation potential (osteoblasts, adipocytes, and chondrocytes). Next, we examined the efficacy of utilizing these stem cells in bone tissue regeneration; the enhanced green fluorescent protein-labeled GMSCs seeded on type I collagen gel were implanted into the mandibular defects as well as the critical-sized calvarial defects in Sprague Dawley rats. We first demonstrated that GMSCs could repair the mandibular wounds and calvarial defects at 2 months in rats postsurgical reconstruction. Histomorphological analysis and image of fluorescence microscope certified that new bone in the defect areas was derived from the transplanted GMSCs. Immunohistochemical analysis of green fluorescent protein, human collagen I, and osteopontin further confirmed our conclusion. The above results implied that mesenchymal stem cells derived from gingival tissue could be a novel source for stem cell-based therapy in bone reconstruction in clinical applications.