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SNX16 negatively regulates the migration and tumorigenesis of MCF-7 cells.

Zhang L, Qin D, Hao C, Shu X, Pei D - Cell Regen (Lond) (2013)

Bottom Line: Ectopic expression of SNX16 reduces the migration and the tumor formation activity of MCF-7 cells.Our results indicate that, in addition to the PI3P, there is a SNX23- and microtubule-dependent cargo transport pathway required for the proper subcellular distribution of SNX16.SNX16 plays a negative regulatory role during cell migration and tumorigenesis.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Regenerative Biology, Chinese Academy of Sciences, and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 China.

ABSTRACT

Background: Sorting nexins are a large family of proteins that are associated with various components of the endosome system and they play many roles in processes such as endocytosis, intracellular protein trafficking and cell signaling. The subcellular distribution patterns of many of them remain controversial and their in vivo functions have not been characterized yet.

Results: We investigated the subcellular distribution and function of SNX16 in this study. SNX16 is detected on Rab5-positive endosomes localized adjacent to focal adhesions at cell cortex. Inhibition of SNX23, polymerization of microtubule filaments as well as the PI3-kinase all disrupt the cell cortex distribution of SNX16. Ectopic expression of SNX16 reduces the migration and the tumor formation activity of MCF-7 cells.

Conclusion: Our results indicate that, in addition to the PI3P, there is a SNX23- and microtubule-dependent cargo transport pathway required for the proper subcellular distribution of SNX16. SNX16 plays a negative regulatory role during cell migration and tumorigenesis.

No MeSH data available.


Related in: MedlinePlus

SNX16 regulates the migration but not proliferation of cells. (A) Stable cell lines expressing SNX16 or an empty vector were established in the HT1080 or MCF-7 cells and the migration activities of these cells were evaluated by the cell migration assay. A typical result of the assay is shown here. (B) Statistical analysis of (A). Ectopic expression of SNX16 reduces the migration of both HT1080 and MCF-7 cells. (C) Both siRNAs to SNX16 efficiently reduce the mRNA level of SNX16 in MCF-7 cells as determined by real-time RT-PCR. (D) Down-regulation of SNX16 by either siRNA enhances the migration of MCF-7 cells. (E, F) Ectopic expression of SNX16 does not change the growth curve (E) or cell cycle profile (F) of MCF-7 cells. Data represent mean ± SD in all cases.
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Fig3: SNX16 regulates the migration but not proliferation of cells. (A) Stable cell lines expressing SNX16 or an empty vector were established in the HT1080 or MCF-7 cells and the migration activities of these cells were evaluated by the cell migration assay. A typical result of the assay is shown here. (B) Statistical analysis of (A). Ectopic expression of SNX16 reduces the migration of both HT1080 and MCF-7 cells. (C) Both siRNAs to SNX16 efficiently reduce the mRNA level of SNX16 in MCF-7 cells as determined by real-time RT-PCR. (D) Down-regulation of SNX16 by either siRNA enhances the migration of MCF-7 cells. (E, F) Ectopic expression of SNX16 does not change the growth curve (E) or cell cycle profile (F) of MCF-7 cells. Data represent mean ± SD in all cases.

Mentions: Previous studies have implicated SNX16 in the signaling pathways such as EGF, BMP and Wnt pathways [33, 34]. These pathways have diverse functions in regulating processes such as cell survival, proliferation or migration. Our observation that SNX16 is present close to focal adhesions further suggests that it might be involved in cell migration. In order to test this possibility, we first established cell lines stably expressing SNX16 in MCF-7 and HT1080 cells. We compared the migration activity of SNX16-expressing cells to the empty vector infected cells using the Cell Motility HCS Reagent Kit. We found that ectopic expression of SNX16 reduces the migration of both cells to less than half of the control levels (Figure 3A and B, P=2.4×10-7 for MCF-7, P=3.4×10-19 for HT1080). We then performed loss-of-function assay on SNX16 and found that the siRNA mediated knockdown of SNX16 enhances the migration of MCF-7 cells (Figure 3C and D, P=0.04 for siSNX16-1 and 0.02 for siSNX16-2 when compared to siCK). We compared the growth curve and cell cycle profile between the vector and SNX16 expressing MCF-7 stable cell lines and found that they are not affected by SNX16 over expression (Figure 3E and F). Together, these results suggest that SNX16 is involved in cell migration but not growth.Figure 3


SNX16 negatively regulates the migration and tumorigenesis of MCF-7 cells.

Zhang L, Qin D, Hao C, Shu X, Pei D - Cell Regen (Lond) (2013)

SNX16 regulates the migration but not proliferation of cells. (A) Stable cell lines expressing SNX16 or an empty vector were established in the HT1080 or MCF-7 cells and the migration activities of these cells were evaluated by the cell migration assay. A typical result of the assay is shown here. (B) Statistical analysis of (A). Ectopic expression of SNX16 reduces the migration of both HT1080 and MCF-7 cells. (C) Both siRNAs to SNX16 efficiently reduce the mRNA level of SNX16 in MCF-7 cells as determined by real-time RT-PCR. (D) Down-regulation of SNX16 by either siRNA enhances the migration of MCF-7 cells. (E, F) Ectopic expression of SNX16 does not change the growth curve (E) or cell cycle profile (F) of MCF-7 cells. Data represent mean ± SD in all cases.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4230745&req=5

Fig3: SNX16 regulates the migration but not proliferation of cells. (A) Stable cell lines expressing SNX16 or an empty vector were established in the HT1080 or MCF-7 cells and the migration activities of these cells were evaluated by the cell migration assay. A typical result of the assay is shown here. (B) Statistical analysis of (A). Ectopic expression of SNX16 reduces the migration of both HT1080 and MCF-7 cells. (C) Both siRNAs to SNX16 efficiently reduce the mRNA level of SNX16 in MCF-7 cells as determined by real-time RT-PCR. (D) Down-regulation of SNX16 by either siRNA enhances the migration of MCF-7 cells. (E, F) Ectopic expression of SNX16 does not change the growth curve (E) or cell cycle profile (F) of MCF-7 cells. Data represent mean ± SD in all cases.
Mentions: Previous studies have implicated SNX16 in the signaling pathways such as EGF, BMP and Wnt pathways [33, 34]. These pathways have diverse functions in regulating processes such as cell survival, proliferation or migration. Our observation that SNX16 is present close to focal adhesions further suggests that it might be involved in cell migration. In order to test this possibility, we first established cell lines stably expressing SNX16 in MCF-7 and HT1080 cells. We compared the migration activity of SNX16-expressing cells to the empty vector infected cells using the Cell Motility HCS Reagent Kit. We found that ectopic expression of SNX16 reduces the migration of both cells to less than half of the control levels (Figure 3A and B, P=2.4×10-7 for MCF-7, P=3.4×10-19 for HT1080). We then performed loss-of-function assay on SNX16 and found that the siRNA mediated knockdown of SNX16 enhances the migration of MCF-7 cells (Figure 3C and D, P=0.04 for siSNX16-1 and 0.02 for siSNX16-2 when compared to siCK). We compared the growth curve and cell cycle profile between the vector and SNX16 expressing MCF-7 stable cell lines and found that they are not affected by SNX16 over expression (Figure 3E and F). Together, these results suggest that SNX16 is involved in cell migration but not growth.Figure 3

Bottom Line: Ectopic expression of SNX16 reduces the migration and the tumor formation activity of MCF-7 cells.Our results indicate that, in addition to the PI3P, there is a SNX23- and microtubule-dependent cargo transport pathway required for the proper subcellular distribution of SNX16.SNX16 plays a negative regulatory role during cell migration and tumorigenesis.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Regenerative Biology, Chinese Academy of Sciences, and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 China.

ABSTRACT

Background: Sorting nexins are a large family of proteins that are associated with various components of the endosome system and they play many roles in processes such as endocytosis, intracellular protein trafficking and cell signaling. The subcellular distribution patterns of many of them remain controversial and their in vivo functions have not been characterized yet.

Results: We investigated the subcellular distribution and function of SNX16 in this study. SNX16 is detected on Rab5-positive endosomes localized adjacent to focal adhesions at cell cortex. Inhibition of SNX23, polymerization of microtubule filaments as well as the PI3-kinase all disrupt the cell cortex distribution of SNX16. Ectopic expression of SNX16 reduces the migration and the tumor formation activity of MCF-7 cells.

Conclusion: Our results indicate that, in addition to the PI3P, there is a SNX23- and microtubule-dependent cargo transport pathway required for the proper subcellular distribution of SNX16. SNX16 plays a negative regulatory role during cell migration and tumorigenesis.

No MeSH data available.


Related in: MedlinePlus