Low doses ionizing radiation enhances the invasiveness of breast cancer cells by inducing epithelial-mesenchymal transition.

Epithelial-mesenchymal transition (EMT) is a process cellular morphologic and molecular alterations facilitate cell invasion. We hypothesized that low dose ionizing irradiation (LDIR) enhances the invasiveness of breast cancer cells by inducing EMT. The effects of LDIR on cellular morphology and the EMT markers of MCF-7 breast cancer cells were analyzed by western blot/RT-PCR and migration/invasion was examined using the transwell assay. We found that LDIR led to the phenotypic changes of EMT in MCF-7 cells and down-regulation of epithelial differentiation markers and transcriptional induction of mesenchymal markers. Furthermore, the radiated cells demonstrated enhanced migration/invasion MCF-7 cells compared with non-radiated cells. In summary, LDIR promotes the invasiveness of breast cancer cells through epithelial to mesenchymal transition. These findings may ultimately provide a new targeted approach for improving the therapeutic effectiveness of radiation in breast cancer.

Zhang X ，Li X ，Zhang N ，Yang Q ，Moran MS ... -  《-》

Ionizing radiation promotes migration and invasion of cancer cells through transforming growth factor-beta-mediated epithelial-mesenchymal transition.

To examine whether ionizing radiation enhances the migratory and invasive abilities of cancer cells through transforming growth factor (TGF-β)-mediated epithelial-mesenchymal transition (EMT). Six cancer cell lines originating from different human organs were irradiated by 60Co γ-ray at a total dose of 2 Gy, and the changes associated with EMT, including morphology, EMT markers, migration and invasion, were observed by microscope, Western blot, immunofluorescence, scratch assay, and transwell chamber assay, respectively. Then the protein levels of TGF-β in these cancer cells were detected by enzyme-linked immunosorbent assay, and the role of TGF-β signaling pathway in the effect of ionizing radiation on EMT was investigate by using the specific inhibitor SB431542. After irradiation with γ-ray at a total dose of 2 Gy, cancer cells presented the mesenchymal phenotype, and compared with the sham-irradiation group the expression of epithelial markers was decreased and of mesenchymal markers was increased, the migratory and invasive capabilities were strengthened, and the protein levels of TGF-β were enhanced. Furthermore, events associated with EMT induced by IR in A549 could be reversed through inhibition of TGF-β signaling. These results suggest that EMT mediated by TGF-β plays a critical role in IR-induced enhancing of migratory and invasive capabilities in cancer cells.

Zhou YC ，Liu JY ，Li J ，Zhang J ，Xu YQ ，Zhang HW ，Qiu LB ，Ding GR ，Su XM ，Mei-Shi ，Guo GZ ... -  《-》

Radiation induces epithelial-mesenchymal transition in colorectal cancer cells.

Kawamoto A ，Yokoe T ，Tanaka K ，Saigusa S ，Toiyama Y ，Yasuda H ，Inoue Y ，Miki C ，Kusunoki M ... -  《-》

FMNL2 enhances invasion of colorectal carcinoma by inducing epithelial-mesenchymal transition.

FMNL2 is a member of diaphanous-related formins that control actin-dependent processes such as cell motility and invasion. Its overexpression in metastatic cell lines and tissues of colorectal carcinoma has been associated with aggressive tumor development in our previous study. But its specific role in cancer is largely unknown. Here we report that FMNL2 is involved in epithelial-mesenchymal transition (EMT) maintenance in human colorectal carcinoma cells. A positive correlation between FMNL2 and vimentin expression and an inverse correlation between FMNL2 and E-cadherin expression were found in colorectal carcinoma cell lines and cancer tissues. Specific knockdown of FMNL2 led to an epithelial-state transition, confirmed by the cobblestone-like phenotype, upregulation of E-cadherin, α-catenin, and γ-catenin, and downregulation of vimentin, snail, slug. Loss of FMNL2 expression lowered the ability of TGF-β to induce cell invasion and EMT, as shown by morphology and the expression levels. Upregulation of vimentin, slug, snail, downregulation of E-cadherin and activation of receptor-Smad3 phosphorylation were observed in M5 and MDCK cells induced by TGF-β, whereas altered expression of these markers was not obvious in FMNL2-depleting M5 cells. High levels of activation of p-MAPK and p-MEK, but not p-PI3K and p-AKT, were observed in SW480/FMNL2+ cells compared with control cells. Treatment with U0126 could abrogate the activation of p-MAPK and p-MEK, whereas LY294002 treatment had no effect on the PI3K/AKT pathway. In conclusion, these findings identify a novel EMT and tumor promoting function for FMNL2, which is involved in TGF-β-induced EMT and colorectal carcinoma cell invasion via Smad3 effectors, or in collaboration with MAPK/MEK pathway.

Li Y ，Zhu X ，Zeng Y ，Wang J ，Zhang X ，Ding YQ ，Liang L ... -  《-》

Low-dose radiation-induced epithelial-mesenchymal transition through NF-κB in cervical cancer cells.

Yan S ，Wang Y ，Yang Q ，Li X ，Kong X ，Zhang N ，Yuan C ，Yang N ，Kong B ... -  《-》