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Flotillin-2 promotes nasopharyngeal carcinoma metastasis and is necessary for the epithelial-mesenchymal transition induced by transforming growth factor-β.

Zhao L, Lin L, Pan C, Shi M, Liao Y, Bin J, Liao W - Oncotarget (2015)

Bottom Line: In this study, we found that Flot2 expression level positively correlated with the cancer stage in NPC tissues.In NPC cells, silencing Flot2 reversed the metastatic effect induced by TGF-β.Moreover, TGF-β-induced Src phosphorylation was significantly inhibited by Flot2 knocking down.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou Guangdong 510515, China.

ABSTRACT
Transforming growth factor-β (TGF-β) promotes cancer metastasis via the epithelial-mesenchymal transition (EMT) but the underlying mechanisms in nasopharyngeal carcinoma (NPC) remain unclear. Flotillin-2 (Flot2), a specialized lipid raft domain in cellular membrane, was reported to promote cancer metastasis. Recently, in neuropathy, it was also suggested that Flot2 was involved in Src activation, which is known as the downstream signal of TGF-β. Therefore, we intended to find out the relationship between Flot2 and TGF-β in the process of nasopharyngeal carcinoma (NPC) metastasis. In this study, we found that Flot2 expression level positively correlated with the cancer stage in NPC tissues. Elevated Flot2 in tumor tissue was an independent prognostic marker, and higher Flot2 expression level showed shorter overall survival time in 181 NPC patients. In NPC cells, silencing Flot2 reversed the metastatic effect induced by TGF-β. Moreover, TGF-β-induced Src phosphorylation was significantly inhibited by Flot2 knocking down. As the consequence of Flot2 inhibition, the expression of the epithelial biomarker E-cadherin was upregulated, while the mesenchymal marker vimentin and signaling transducer β-catenin was suppressed. In conclusions, Flot2 is an indispensable member for TGF-β signaling, which is essential for the EMT process in NPC metastasis. Suppressing Flot2 may be a novel way against TGF-β-induced EMT.

No MeSH data available.


Related in: MedlinePlus

Silencing Flot2 alone does not changed NPC cell motility(A) Efficiency of three siRNA sequences against Flot2 was evaluated by Quantitative real-time PCR. (B to D) CNE-1 cell motility was not affected by any of the three Flot2-silencing siRNAs. (B) Cell scattering and morphology. Scale bar = 50μm. (C) Wound-healing assay and (D) Transwell assay. (E) Flot2 silencing has no influence on the expression of EMT makers (E-cadherin, vimentin and β-catenin), TGF-β receptor 1 or total Src in CNE-1 cells. #P<0.01, +P<0.001.
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Figure 5: Silencing Flot2 alone does not changed NPC cell motility(A) Efficiency of three siRNA sequences against Flot2 was evaluated by Quantitative real-time PCR. (B to D) CNE-1 cell motility was not affected by any of the three Flot2-silencing siRNAs. (B) Cell scattering and morphology. Scale bar = 50μm. (C) Wound-healing assay and (D) Transwell assay. (E) Flot2 silencing has no influence on the expression of EMT makers (E-cadherin, vimentin and β-catenin), TGF-β receptor 1 or total Src in CNE-1 cells. #P<0.01, +P<0.001.

Mentions: The efficiency of silencing was verified using Quantitative real-time PCR. All of the three siFlot2 successfully suppressed Flot2 mRNA expression, and siFlot2-#1 was the most efficient one (Figure 5A). These siFlot2 were added into CNE-1 and 6–10B cells. Out off our anticipation, silencing Flot2 did not alter cell morphology or cell scattering (Figure 5B). Likewise, neither in the experiment of transwell (Figure 5C) nor in the wound-healing assay (Figure 5D), none of the three Flot2 silencing sequences showed significant changes on the motility of NPC cells. In protein level, although all of the three siRNA sequences decreased Flot2 expression profoundly, it seemed they did not have significant influence on the expression of E-cadherin, vimentin or β-catenin (Figure 5E). We also hypothesized that Flot2 might be associated with TGF-β signaling. However, by Flot2 suppression, no alterations were found in the expression of the TGF-β receptor or Src (Figure 5E). These results indicate that altering Flot2 is not sufficient to influence NPC cell motility.


Flotillin-2 promotes nasopharyngeal carcinoma metastasis and is necessary for the epithelial-mesenchymal transition induced by transforming growth factor-β.

Zhao L, Lin L, Pan C, Shi M, Liao Y, Bin J, Liao W - Oncotarget (2015)

Silencing Flot2 alone does not changed NPC cell motility(A) Efficiency of three siRNA sequences against Flot2 was evaluated by Quantitative real-time PCR. (B to D) CNE-1 cell motility was not affected by any of the three Flot2-silencing siRNAs. (B) Cell scattering and morphology. Scale bar = 50μm. (C) Wound-healing assay and (D) Transwell assay. (E) Flot2 silencing has no influence on the expression of EMT makers (E-cadherin, vimentin and β-catenin), TGF-β receptor 1 or total Src in CNE-1 cells. #P<0.01, +P<0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496397&req=5

Figure 5: Silencing Flot2 alone does not changed NPC cell motility(A) Efficiency of three siRNA sequences against Flot2 was evaluated by Quantitative real-time PCR. (B to D) CNE-1 cell motility was not affected by any of the three Flot2-silencing siRNAs. (B) Cell scattering and morphology. Scale bar = 50μm. (C) Wound-healing assay and (D) Transwell assay. (E) Flot2 silencing has no influence on the expression of EMT makers (E-cadherin, vimentin and β-catenin), TGF-β receptor 1 or total Src in CNE-1 cells. #P<0.01, +P<0.001.
Mentions: The efficiency of silencing was verified using Quantitative real-time PCR. All of the three siFlot2 successfully suppressed Flot2 mRNA expression, and siFlot2-#1 was the most efficient one (Figure 5A). These siFlot2 were added into CNE-1 and 6–10B cells. Out off our anticipation, silencing Flot2 did not alter cell morphology or cell scattering (Figure 5B). Likewise, neither in the experiment of transwell (Figure 5C) nor in the wound-healing assay (Figure 5D), none of the three Flot2 silencing sequences showed significant changes on the motility of NPC cells. In protein level, although all of the three siRNA sequences decreased Flot2 expression profoundly, it seemed they did not have significant influence on the expression of E-cadherin, vimentin or β-catenin (Figure 5E). We also hypothesized that Flot2 might be associated with TGF-β signaling. However, by Flot2 suppression, no alterations were found in the expression of the TGF-β receptor or Src (Figure 5E). These results indicate that altering Flot2 is not sufficient to influence NPC cell motility.

Bottom Line: In this study, we found that Flot2 expression level positively correlated with the cancer stage in NPC tissues.In NPC cells, silencing Flot2 reversed the metastatic effect induced by TGF-β.Moreover, TGF-β-induced Src phosphorylation was significantly inhibited by Flot2 knocking down.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou Guangdong 510515, China.

ABSTRACT
Transforming growth factor-β (TGF-β) promotes cancer metastasis via the epithelial-mesenchymal transition (EMT) but the underlying mechanisms in nasopharyngeal carcinoma (NPC) remain unclear. Flotillin-2 (Flot2), a specialized lipid raft domain in cellular membrane, was reported to promote cancer metastasis. Recently, in neuropathy, it was also suggested that Flot2 was involved in Src activation, which is known as the downstream signal of TGF-β. Therefore, we intended to find out the relationship between Flot2 and TGF-β in the process of nasopharyngeal carcinoma (NPC) metastasis. In this study, we found that Flot2 expression level positively correlated with the cancer stage in NPC tissues. Elevated Flot2 in tumor tissue was an independent prognostic marker, and higher Flot2 expression level showed shorter overall survival time in 181 NPC patients. In NPC cells, silencing Flot2 reversed the metastatic effect induced by TGF-β. Moreover, TGF-β-induced Src phosphorylation was significantly inhibited by Flot2 knocking down. As the consequence of Flot2 inhibition, the expression of the epithelial biomarker E-cadherin was upregulated, while the mesenchymal marker vimentin and signaling transducer β-catenin was suppressed. In conclusions, Flot2 is an indispensable member for TGF-β signaling, which is essential for the EMT process in NPC metastasis. Suppressing Flot2 may be a novel way against TGF-β-induced EMT.

No MeSH data available.


Related in: MedlinePlus