Human adipose-derived stromal/stem cells are distinct from dermal fibroblasts as evaluated by biological characterization and RNA sequencing

Human adipose-derived stromal/stem cells (ASC) have immunomodulatory properties and the potential to differentiate into several cell lines, important for application in regenerative medicine. However, the contamination with dermal fibroblasts (FIB) can impair the beneficial effects of ASC in cell therapy. It is then essential to develop new strategies that contribute to the distinction between these two cell types. In this study, we performed functional assays, high-throughput RNA sequencing (RNA-Seq) and quantitative PCR (qPCR) to find new markers that can distinguish ASC and FIB. We showed that ASC have adipogenic and osteogenic differentiation capacity and alkaline phosphatase activity, not observed in FIB. Gene expression variation analysis identified more than 2000 differentially expressed genes (DEG) between these two cell types. We validated 16 genes present in the list of DEG, including the alkaline phosphatase gene (ALPL). In conclusion, we showed that ASC and FIB have distinct biological properties as demonstrated by alkaline phosphatase activity and differentiation capacity, besides having different gene expression profiles. SIGNIFICANCE OF THE STUDY: Although many differences between stromal stem cells derived from human adipose tissue (ASC) and human dermal fibroblasts (FIB) are described, it is still difficult to find specific markers to differentiate them. This problem can interfere with the therapeutic use of ASC. This work aimed to find new markers to differentiate these two cell populations. Our findings suggest that these cells can be distinguished by biological and molecular characteristics, such as adipogenic and osteogenic differentiation, alkaline phosphatase activity and differential gene expression profiles. The DEG were related to the regulation of the cell cycle, development process, structural organization of the cell and synthesis of the extracellular matrix. This study helps to find new cellular markers to distinguish the two populations and to better understand the properties of these cells, which can improve cell therapy.

Expression of epidermal growth factor receptor (EGFR) in cholangiocarcinomas: predictive factors and survival

OBJECTIVE

to evaluate the expression of the epithelial growth factor receptor (EGFR) by immunohistochemistry, and to verify its association with prognostic factors and survival of patients operated by cholangiocarcinoma.

METHODS

we verified the immunohistochemical expression of EGFR in 35 surgical specimens of cholangiocarcinoma (CCA). We obtained survival curves with the Kaplan-Meier method.

RESULTS

we found significant EGFR expression in ten (28.6%) of the 35 CCAs, eight with score 3 and two with score 2. Advanced stages (III and IV) presented higher EGFR expression (p=0.07). The clinical characteristics that were most associated with positive EGFR expression were female gender (p=0.06) and absence of comorbidities (p=0.06). Overall survival at 12, 24, 36 and 48 months was 100%, 82.5%, 59% and 44.2%, respectively. The survival of EGFR positive patients at 12, 24, 36 and 48 months was 100%, 75%, 50% and 0%, whereas for negative EGFR patients it was 100%, 87.5%, 65.6% and 65.6%, respectively.

CONCLUSION

EGFR expression occurred in 28.6% of the cases studied and was associated with lower survival.