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FAM83D promotes cell proliferation and motility by downregulating tumor suppressor gene FBXW7.

Wang Z, Liu Y, Zhang P, Zhang W, Wang W, Curr K, Wei G, Mao JH - Oncotarget (2013)

Bottom Line: The list of candidate oncogenes in 20q has expanded over the past decade.High expression levels of FAM83D are significantly associated with poor clinical outcome and distant metastasis in breast cancer patients.Mechanistic studies reveal that overexpression of FAM83D downregulates FBXW7 expression levels through a physical interaction, which results in elevated protein levels of oncogenic substrates downstream to FBXW7, such as mTOR, whose inhibition by rapamycin can suppress FAM83D-induced cell migration and invasion.

View Article: PubMed Central - PubMed

Affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, USA.

ABSTRACT
Amplification of chromosome 20q is frequently found in various types of human cancers, including breast cancer. The list of candidate oncogenes in 20q has expanded over the past decade. Here, we investigate whether FAM83D (family with sequence similarity 83, member D) on chromosome 20q plays any role in breast cancer development. The expression level of FAM83D is significantly elevated in breast cancer cell lines and primary human breast cancers. High expression levels of FAM83D are significantly associated with poor clinical outcome and distant metastasis in breast cancer patients. We show that ectopic expression of FAM83D in human mammary epithelial cells promotes cell proliferation, migration and invasion along with epithelial-mesenchymal transition (EMT). Ablation of FAM83D in breast cancer cells induces apoptosis and consequently inhibits cell proliferation and colony formation. Mechanistic studies reveal that overexpression of FAM83D downregulates FBXW7 expression levels through a physical interaction, which results in elevated protein levels of oncogenic substrates downstream to FBXW7, such as mTOR, whose inhibition by rapamycin can suppress FAM83D-induced cell migration and invasion. The results demonstrate that FAM83D has prognostic value for breast cancer patients and is a novel oncogene in breast cancer development that at least in part acts through mTOR hyper-activation by inhibiting FBXW7.

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Overexpression of FAM83D in MCF10A cells leads to an epithelial-mesenchymal transition(A) Representative micrographs of MCF10A-FAM83D and MCF10A control cells under bright field display significant differences in morphology. (B) Western analysis of E-cadherin and vimentin indicates EMT in MCF10A-FAM83D compared to MCF10A control cells. Loading control is β-actin. (C) Immunofluorescent staining of E-cadherin (red, upper panels) and vimentin (green, lower panels) demonstrates EMT in MCF10A-FAM83D compared to MCF10A control cells. DNA is stained by DAPI (blue).
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Figure 4: Overexpression of FAM83D in MCF10A cells leads to an epithelial-mesenchymal transition(A) Representative micrographs of MCF10A-FAM83D and MCF10A control cells under bright field display significant differences in morphology. (B) Western analysis of E-cadherin and vimentin indicates EMT in MCF10A-FAM83D compared to MCF10A control cells. Loading control is β-actin. (C) Immunofluorescent staining of E-cadherin (red, upper panels) and vimentin (green, lower panels) demonstrates EMT in MCF10A-FAM83D compared to MCF10A control cells. DNA is stained by DAPI (blue).

Mentions: Given that ectopic expression of FAM83D increased cell motility and invasiveness, we next examined whether FAM83D overexpression could affect cell morphology. MCF10A-FAM83D cells exhibited a discohesive growth pattern and a spindle-shaped fibroblastic morphology, hallmarks of a mesenchymal phenotype, which was not observed in vector-only control cells (Fig. 4A). Consistently, the protein level of an epithelial marker E-cadherin is mildly suppressed in MCF10A-FAM83D cells (Fig. 4B). Moreover, immunofluorescent staining showed that the clear membrane distribution of E-cadherin MCF10A-control cells display, consistent with its normal function in cell-cell adhesion, was absent in MCF10A-FAM83D cells, and instead was enriched in the cytoplasm (Fig. 4C). Additionally, we found that Vimentin, a mesenchymal marker, dramatically increased in MCF10A-FAM83D cells (Fig. 4D). These findings suggest that FAM83D overexpression induces EMT.


FAM83D promotes cell proliferation and motility by downregulating tumor suppressor gene FBXW7.

Wang Z, Liu Y, Zhang P, Zhang W, Wang W, Curr K, Wei G, Mao JH - Oncotarget (2013)

Overexpression of FAM83D in MCF10A cells leads to an epithelial-mesenchymal transition(A) Representative micrographs of MCF10A-FAM83D and MCF10A control cells under bright field display significant differences in morphology. (B) Western analysis of E-cadherin and vimentin indicates EMT in MCF10A-FAM83D compared to MCF10A control cells. Loading control is β-actin. (C) Immunofluorescent staining of E-cadherin (red, upper panels) and vimentin (green, lower panels) demonstrates EMT in MCF10A-FAM83D compared to MCF10A control cells. DNA is stained by DAPI (blue).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3926842&req=5

Figure 4: Overexpression of FAM83D in MCF10A cells leads to an epithelial-mesenchymal transition(A) Representative micrographs of MCF10A-FAM83D and MCF10A control cells under bright field display significant differences in morphology. (B) Western analysis of E-cadherin and vimentin indicates EMT in MCF10A-FAM83D compared to MCF10A control cells. Loading control is β-actin. (C) Immunofluorescent staining of E-cadherin (red, upper panels) and vimentin (green, lower panels) demonstrates EMT in MCF10A-FAM83D compared to MCF10A control cells. DNA is stained by DAPI (blue).
Mentions: Given that ectopic expression of FAM83D increased cell motility and invasiveness, we next examined whether FAM83D overexpression could affect cell morphology. MCF10A-FAM83D cells exhibited a discohesive growth pattern and a spindle-shaped fibroblastic morphology, hallmarks of a mesenchymal phenotype, which was not observed in vector-only control cells (Fig. 4A). Consistently, the protein level of an epithelial marker E-cadherin is mildly suppressed in MCF10A-FAM83D cells (Fig. 4B). Moreover, immunofluorescent staining showed that the clear membrane distribution of E-cadherin MCF10A-control cells display, consistent with its normal function in cell-cell adhesion, was absent in MCF10A-FAM83D cells, and instead was enriched in the cytoplasm (Fig. 4C). Additionally, we found that Vimentin, a mesenchymal marker, dramatically increased in MCF10A-FAM83D cells (Fig. 4D). These findings suggest that FAM83D overexpression induces EMT.

Bottom Line: The list of candidate oncogenes in 20q has expanded over the past decade.High expression levels of FAM83D are significantly associated with poor clinical outcome and distant metastasis in breast cancer patients.Mechanistic studies reveal that overexpression of FAM83D downregulates FBXW7 expression levels through a physical interaction, which results in elevated protein levels of oncogenic substrates downstream to FBXW7, such as mTOR, whose inhibition by rapamycin can suppress FAM83D-induced cell migration and invasion.

View Article: PubMed Central - PubMed

Affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA, USA.

ABSTRACT
Amplification of chromosome 20q is frequently found in various types of human cancers, including breast cancer. The list of candidate oncogenes in 20q has expanded over the past decade. Here, we investigate whether FAM83D (family with sequence similarity 83, member D) on chromosome 20q plays any role in breast cancer development. The expression level of FAM83D is significantly elevated in breast cancer cell lines and primary human breast cancers. High expression levels of FAM83D are significantly associated with poor clinical outcome and distant metastasis in breast cancer patients. We show that ectopic expression of FAM83D in human mammary epithelial cells promotes cell proliferation, migration and invasion along with epithelial-mesenchymal transition (EMT). Ablation of FAM83D in breast cancer cells induces apoptosis and consequently inhibits cell proliferation and colony formation. Mechanistic studies reveal that overexpression of FAM83D downregulates FBXW7 expression levels through a physical interaction, which results in elevated protein levels of oncogenic substrates downstream to FBXW7, such as mTOR, whose inhibition by rapamycin can suppress FAM83D-induced cell migration and invasion. The results demonstrate that FAM83D has prognostic value for breast cancer patients and is a novel oncogene in breast cancer development that at least in part acts through mTOR hyper-activation by inhibiting FBXW7.

Show MeSH
Related in: MedlinePlus