Oxidative stress regulation and related metabolic pathways in epithelial-mesenchymal transition of breast cancer stem cells.

Epithelial-mesenchymal transition (EMT) is a cell remodeling process in which epithelial cells undergo a reversible phenotype switch via the loss of adhesion capacity and acquisition of mesenchymal characteristics. In other words, EMT activation can increase invasiveness and metastatic properties, and prevent the sensitivity of tumor cells to chemotherapeutics, as mesenchymal cells have a higher resistance to chemotherapy and immunotherapy. EMT is orchestrated by a complex and multifactorial network, often linked to episodic, transient, or partial events. A variety of factors have been implicated in EMT development. Based on this concept, multiple metabolic pathways and master transcription factors, such as Snail, Twist, and ZEB, can drive the EMT. Emerging evidence suggests that oxidative stress plays a significant role in EMT induction. One emerging theory is that reducing mitochondrial-derived reactive oxygen species production may contribute to EMT development. This review describes how metabolic pathways and transcription factors are linked to EMT induction and addresses the involvement of signaling pathways.

Curcumin Affects Adipose Tissue-Derived Mesenchymal Stem Cell Aging Through TERT Gene Expression.

Aging and losing cell survival is one of the main problems in cell therapy. Aging of Mesenchymal Stem Cells (MSCs) is associated with a rise in intracellular reactive oxygen species, decrease in telomerase reverse transcriptase (TERT) expression and finally eroded telomere ends. Given that the production of free radicals in the aging process is effective, the use of antioxidants can help in scavenging free radicals and prevent the aging of cells. The aim of this study is to evaluate the effects of curcumin on proliferation, aging and TERT expression of rat adipose tissue-derived stem cells (rADSC). rADSCs were isolated from inguinal rat adipose tissue and their viabilities were assessed by MTT after exposure to different concentrations of curcumin. Flow-cytometry was performed for investigating the cell surface markers. Adipogenic and osteogenic differentiation were carried out to evaluate the pluripotency of rADSCs. Telomerase expression and percentage of senescent cells were evaluated using real-time PCR and senescence-associated ß-galactosidase activity, respectively. The results demonstrated significant proliferation of rADSCs after 48 h treatment with 1 and 5 µM curcumin. Additionally, these concentrations could significantly reduce the population doubling time and aging of rADSCs at different passages. The findings of SA-ß-gal staining showed that curcumin significantly decreased the number of senescent cells in the 5 and 7 cell passages. Moreover, expression levels of TERT increased in the presence of 1 and 5 µM curcumin than control group (P<0.001). As a conclusion, curcumin may be a good candidate to improve lifespan of rADSCs through promoting TERT gene expression.