DESIGN: The role of matrix stiffness in several cancers including oral cancer was reviewed with a tailored search strategy using relevant keywords as per the Medline format. The role of molecular mediators, Yes-associated protein 1 (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) was weighed in the context of OSF along two distinct pathways.
RESULTS: Increased matrix stiffness activates the transcriptional coactivators, YAP and TAZ shuttling between the nucleus and cytoplasm. YAP and TAZ, serve as mechanical transducers in promoting cell migration, invasion and epithelial-mesenchymal transition (EMT). The hypoxic microenvironment in the advanced stage of OSF promotes the migratory phenotype through mechanical memory.
CONCLUSIONS: Reprogramming of a stiff matrix has the potential to restore the Hippo-YAP/TAZ tumor suppressor pathway and reverse fibrosis-associated tumor development.
METHODS: Human adipose-derived MSCs (Ad-MSCs) and A549 cells are co-cultured together in indirect co-culture system using Transwell insert. Following co-culture, both cells were analysed in terms of growth rate, migration ability, apoptosis and gene expression for genes involved in migration and stemness characteristics.
RESULTS: The result shows that Ad-MSCs promoted the growth of A549 cells when indirectly co-cultured for 48 and 72 h. Furthermore, Ad-MSCs significantly enhanced the migration rate of A549 cells. The increased in migration rate was in parallel with the significant increase of MMP9. There are no significant changes observed in the expression of TWIST2, CDH2 and CDH1, genes involved in the epithelial-to-mesenchymal transition (EMT). Ad-MSCs also protect A549 cancer cells from undergoing apoptosis and increase the survival of cancer cells.
CONCLUSION: Secretion of soluble factors from Ad-MSCs has been shown to promote the growth and metastatic characteristics of A549 cancer cells. Therefore, the use of Ad-MSCs in cancer therapy needs to be carefully evaluated in the long-term aspect.
METHODS: Respiratory epithelial cells were isolated and divided into four groups: control (untreated), treated with 0.05% OE (OE group), EMT induced with 5 ng/ml of transforming growth factor beta-1 (TGFβ1 group) and treated with 5 ng/ml TGFβ1 + 0.05% OE (TGFβ1 + OE group). The effects of OE treatment on growth kinetics, morphology and protein expression in RECs were evaluated. Immunocytochemistry analysis was performed to quantitate the total percentage of E-cadherin and vimentin expression from day 1 to day 3.
RESULTS: There were no significant differences between untreated RECs and OE-treated RECs in terms of their morphology, growth kinetics and protein expression. Induction with TGFβ1 caused RECs to have an elongated spindle shape, a slower proliferation rate, a higher expression of vimentin and a lower expression of E-cadherin compared with the control. Cells in the TGFβ1 + OE group had similar epithelial shape to untreated group however it had no significant differences in their proliferation rate when compared to TGFβ1-induced RECs. Cells treated with TGFβ1 + OE showed significantly reduced expression of vimentin and increased expression of E-cadherin compared with the TGFβ1 group (P
METHODS: A miR-524-5p precursor was introduced into human fibroblast HFF-1 in the presence of OSKM, and the relative number of embryonic stem cell (ESC)-like colonies that stained positively with alkaline phosphatase (AP) and Nanog were quantified to determine reprogramming efficiency. A miR-524-5p mimic was transfected to MSCs to investigate the effects of miR-524-5p on TP53INP1, ZEB2, and SMAD4 expression by real-time polymerase chain reaction (PCR) and Western blot. Direct gene targeting was confirmed by luciferase activity. A phylogenetic tree of TP53INP1 was constructed by the Clustal method. Contribution of miR-524-5p to cell proliferation and apoptosis was examined by cell counts, BrdU, MTT, and cell death assays, and pluripotency gene expression by real-time PCR.
RESULTS: Co-expressing the miR-524 precursor with OSKM resulted in a two-fold significant increase in the number of AP- and Nanog-positive ESC-like colonies, indicating a role for miR-524-5p in reprogramming. The putative target, TP53INP1, showed an inverse expression relationship with miR-524-5p; direct TP53INP1 targeting was confirmed in luciferase assays. miR-524-5p-induced TP53INP1 downregulation enhanced cell proliferation, suppressed apoptosis, and upregulated the expression of pluripotency genes, all of which are critical early events of the reprogramming process. Interestingly, the TP53INP1 gene may have co-evolved late with the primate-specific miR-524-5p. miR-524-5p also promoted mesenchymal-to-epithelial transition (MET), a required initial event of reprogramming, by directly targeting the epithelial-to-mesenchymal transition (EMT)-related genes, ZEB2 and SMAD4.
CONCLUSIONS: Via targeting TP53INP1, ZEB2, and SMAD4, miR-524-5p contributes to the early stage of inducing pluripotency by promoting cell proliferation, inhibiting apoptosis, upregulating expression of pluripotency genes, and enhancing MET. Other C19MC miRNAs may have similar reprogramming functions.