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Trail resistance induces epithelial-mesenchymal transition and enhances invasiveness by suppressing PTEN via miR-221 in breast cancer.

Wang H, Xu C, Kong X, Li X, Kong X, Wang Y, Ding X, Yang Q - PLoS ONE (2014)

Bottom Line: In our present experiment, we successfully utilized breast cancer cell line MDA-MB-231 to establish TRAIL-resistant cell line.We found resistance to TRAIL could induce epithelial-mesenchymal transition (EMT) and enhance invasiveness.Re-expression of miR-221 or targeting PTEN might serve as potential therapeutic approaches for the treatment of Trail-resistant breast cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, Qilu Hospital, Shandong University, Jinan, Shandong Province, China; Department of Oncology, Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong Province, China; Department of Breast Surgery, Qilu Hospital, Shandong University, Jinan, Shandong Province, China.

ABSTRACT
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively induce apoptosis of cancer cells and is verified effective to various cancers. However, a variety of breast cancer cell lines are resistant to TRAIL and the mechanisms of resistance are largely unknown. In our present experiment, we successfully utilized breast cancer cell line MDA-MB-231 to establish TRAIL-resistant cell line. We found resistance to TRAIL could induce epithelial-mesenchymal transition (EMT) and enhance invasiveness. We further demonstrated PTEN was down-regulated in TRAIL-resistant cells. Silencing miR-221, PTEN expression was up-regulated, the process of EMT could be reversed, and the ability of migration and invasion were correspondingly weakened. We also demonstrated knockdown of miR-221 could reverse resistance to TRAIL partially by targeting PTEN. Our findings suggest that resistance to TRAIL could induce EMT and enhance invasiveness by suppressing PTEN via miR-221. Re-expression of miR-221 or targeting PTEN might serve as potential therapeutic approaches for the treatment of Trail-resistant breast cancer.

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Down-regulation of PTEN resulted in resistance to TRAIL of 231 cells, EMT and enhancement of invasiveness.A. PTEN was down-regulated in 231T cells compared with 231. B. MDA-MB-231 cells transfected with siPTEN and its corresponding NC were named as 231-siPTEN and 231-n respectively. Tolerance of 231-n cells and 231-siPTEN cells to different concentrations of TRAIL was examined by MTT assay. Points represented the average of three independent experiments. Bars stood for SD; C. Migration and invasion assay of 231-n cells and 231-siPTEN cells. Count the cells in 10 representative fields under a light microscope. D. N-cadherin, fibronectin, vimentin and Snail of 231-n and 231-siPTEN cells were detected by western blot assay. Also β-actin was used as control. E. Summary graphs for migration and invasion, respectively. Data were shown as mean ± SD. *P<0.05; **P<0.01.
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pone-0099067-g004: Down-regulation of PTEN resulted in resistance to TRAIL of 231 cells, EMT and enhancement of invasiveness.A. PTEN was down-regulated in 231T cells compared with 231. B. MDA-MB-231 cells transfected with siPTEN and its corresponding NC were named as 231-siPTEN and 231-n respectively. Tolerance of 231-n cells and 231-siPTEN cells to different concentrations of TRAIL was examined by MTT assay. Points represented the average of three independent experiments. Bars stood for SD; C. Migration and invasion assay of 231-n cells and 231-siPTEN cells. Count the cells in 10 representative fields under a light microscope. D. N-cadherin, fibronectin, vimentin and Snail of 231-n and 231-siPTEN cells were detected by western blot assay. Also β-actin was used as control. E. Summary graphs for migration and invasion, respectively. Data were shown as mean ± SD. *P<0.05; **P<0.01.

Mentions: To clarify the molecular mechanisms of resistance to TRAIL and the induction of EMT, we detected PTEN in 231T cells and found it was down-regulated in 231T cells (Figure 4A). We further interfered the expression of PTEN in 231 cells. Then MTT assay, western blot and Transwell test were all performed with cells transfected with siRNA of PTEN (231-siPTEN) and its negative control (231-n). Knockdown of PTEN resulted in insensitivity to TRAIL of 231 cells (Figure 4B). Results of western blot exhibited that the EMT markers and transcriptional marker Snail tested in the previous experiments were all up-regulated (Figure 4D). Moreover, cells abilities of migration and invasion were enhanced once again after interference the expression of PTEN (Figure 4C and E). So we concluded that PTEN down-regulation could lead to TRAIL-resistance, EMT, enhancement of migration and invasion.


Trail resistance induces epithelial-mesenchymal transition and enhances invasiveness by suppressing PTEN via miR-221 in breast cancer.

Wang H, Xu C, Kong X, Li X, Kong X, Wang Y, Ding X, Yang Q - PLoS ONE (2014)

Down-regulation of PTEN resulted in resistance to TRAIL of 231 cells, EMT and enhancement of invasiveness.A. PTEN was down-regulated in 231T cells compared with 231. B. MDA-MB-231 cells transfected with siPTEN and its corresponding NC were named as 231-siPTEN and 231-n respectively. Tolerance of 231-n cells and 231-siPTEN cells to different concentrations of TRAIL was examined by MTT assay. Points represented the average of three independent experiments. Bars stood for SD; C. Migration and invasion assay of 231-n cells and 231-siPTEN cells. Count the cells in 10 representative fields under a light microscope. D. N-cadherin, fibronectin, vimentin and Snail of 231-n and 231-siPTEN cells were detected by western blot assay. Also β-actin was used as control. E. Summary graphs for migration and invasion, respectively. Data were shown as mean ± SD. *P<0.05; **P<0.01.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4048247&req=5

pone-0099067-g004: Down-regulation of PTEN resulted in resistance to TRAIL of 231 cells, EMT and enhancement of invasiveness.A. PTEN was down-regulated in 231T cells compared with 231. B. MDA-MB-231 cells transfected with siPTEN and its corresponding NC were named as 231-siPTEN and 231-n respectively. Tolerance of 231-n cells and 231-siPTEN cells to different concentrations of TRAIL was examined by MTT assay. Points represented the average of three independent experiments. Bars stood for SD; C. Migration and invasion assay of 231-n cells and 231-siPTEN cells. Count the cells in 10 representative fields under a light microscope. D. N-cadherin, fibronectin, vimentin and Snail of 231-n and 231-siPTEN cells were detected by western blot assay. Also β-actin was used as control. E. Summary graphs for migration and invasion, respectively. Data were shown as mean ± SD. *P<0.05; **P<0.01.
Mentions: To clarify the molecular mechanisms of resistance to TRAIL and the induction of EMT, we detected PTEN in 231T cells and found it was down-regulated in 231T cells (Figure 4A). We further interfered the expression of PTEN in 231 cells. Then MTT assay, western blot and Transwell test were all performed with cells transfected with siRNA of PTEN (231-siPTEN) and its negative control (231-n). Knockdown of PTEN resulted in insensitivity to TRAIL of 231 cells (Figure 4B). Results of western blot exhibited that the EMT markers and transcriptional marker Snail tested in the previous experiments were all up-regulated (Figure 4D). Moreover, cells abilities of migration and invasion were enhanced once again after interference the expression of PTEN (Figure 4C and E). So we concluded that PTEN down-regulation could lead to TRAIL-resistance, EMT, enhancement of migration and invasion.

Bottom Line: In our present experiment, we successfully utilized breast cancer cell line MDA-MB-231 to establish TRAIL-resistant cell line.We found resistance to TRAIL could induce epithelial-mesenchymal transition (EMT) and enhance invasiveness.Re-expression of miR-221 or targeting PTEN might serve as potential therapeutic approaches for the treatment of Trail-resistant breast cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, Qilu Hospital, Shandong University, Jinan, Shandong Province, China; Department of Oncology, Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong Province, China; Department of Breast Surgery, Qilu Hospital, Shandong University, Jinan, Shandong Province, China.

ABSTRACT
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively induce apoptosis of cancer cells and is verified effective to various cancers. However, a variety of breast cancer cell lines are resistant to TRAIL and the mechanisms of resistance are largely unknown. In our present experiment, we successfully utilized breast cancer cell line MDA-MB-231 to establish TRAIL-resistant cell line. We found resistance to TRAIL could induce epithelial-mesenchymal transition (EMT) and enhance invasiveness. We further demonstrated PTEN was down-regulated in TRAIL-resistant cells. Silencing miR-221, PTEN expression was up-regulated, the process of EMT could be reversed, and the ability of migration and invasion were correspondingly weakened. We also demonstrated knockdown of miR-221 could reverse resistance to TRAIL partially by targeting PTEN. Our findings suggest that resistance to TRAIL could induce EMT and enhance invasiveness by suppressing PTEN via miR-221. Re-expression of miR-221 or targeting PTEN might serve as potential therapeutic approaches for the treatment of Trail-resistant breast cancer.

Show MeSH
Related in: MedlinePlus