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Deltex-3-like (DTX3L) stimulates metastasis of melanoma through FAK/PI3K/AKT but not MEK/ERK pathway.

Thang ND, Yajima I, Kumasaka MY, Iida M, Suzuki T, Kato M - Oncotarget (2015)

Bottom Line: Deltex-3-like (DTX3L), an E3 ligase, is a member of the Deltex (DTX) family and is also called B-lymphoma and BAL-associated protein (BBAP).Our analysis in human BRAFV600E inhibitor-resistant melanoma cells showed about 80% decreased invasion in the DTX3L-depleted cells compared to that in the DTX3L-intact cells.Thus, DTX3L is clinically a potential therapeutic target as well as a potential biomarker for melanoma.

View Article: PubMed Central - PubMed

Affiliation: Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai-shi, Aichi, Japan.

ABSTRACT
Deltex-3-like (DTX3L), an E3 ligase, is a member of the Deltex (DTX) family and is also called B-lymphoma and BAL-associated protein (BBAP). Previously, we established RFP/RET-transgenic mice, in which systemic hyperpigmented skin, benign melanocytic tumor(s) and melanoma(s) develop stepwise. Here we showed that levels of Dtx3l/DTX3L in spontaneous melanoma in RFP/RET-transgenic mice and human melanoma cell lines were significantly higher than those in benign melanocytic cells and primarily cultured normal human epithelial melanocytes, respectively. Immunohistochemical analysis of human tissues showed that more than 80% of the melanomas highly expressed DTX3L. Activity of FAK/PI3K/AKT signaling, but not that of MEK/ERK signaling, was decreased in Dtx3l/DTX3L-depleted murine and human melanoma cells. In summary, we demonstrated not only increased DTX3L level in melanoma cells but also DTX3L-mediated regulation of invasion and metastasis in melanoma through FAK/PI3K/AKT but not MEK/ERK signaling. Our analysis in human BRAFV600E inhibitor-resistant melanoma cells showed about 80% decreased invasion in the DTX3L-depleted cells compared to that in the DTX3L-intact cells. Thus, DTX3L is clinically a potential therapeutic target as well as a potential biomarker for melanoma.

No MeSH data available.


Related in: MedlinePlus

Decreased cell invasion of DTX3L-depleted human melanoma cellsMatrigel-invasion assay was performed with control (Si-Control) and DTX3L-depleted (Si-DTX3L) G361 human melanoma cells A. Photographs of cells invading the membrane stained with hematoxylin are presented (left). After invading cells had been counted in five random microscopic fields in each Matrigel-invasion assay, the results of three independent assays were normalized and are presented as an invasion index (right). Expression (DTX3L, FAK, PI3K, AKT, MEK and ERK) and phosphorylation (pFAK, pPI3K, pAKT, pMEK and pERK) levels in two kinds of DTX3L-depeleted (Si-DTX3L) and control (Si-Control) human melanoma cells determined by immunoblot analysis are presented B. Expression levels of α-TUBULIN protein are presented as an internal control B. Significantly different (**, p < 0.01) from the control (Si-Control) by Student's t-test. Scale bar, 50 μM.
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Figure 5: Decreased cell invasion of DTX3L-depleted human melanoma cellsMatrigel-invasion assay was performed with control (Si-Control) and DTX3L-depleted (Si-DTX3L) G361 human melanoma cells A. Photographs of cells invading the membrane stained with hematoxylin are presented (left). After invading cells had been counted in five random microscopic fields in each Matrigel-invasion assay, the results of three independent assays were normalized and are presented as an invasion index (right). Expression (DTX3L, FAK, PI3K, AKT, MEK and ERK) and phosphorylation (pFAK, pPI3K, pAKT, pMEK and pERK) levels in two kinds of DTX3L-depeleted (Si-DTX3L) and control (Si-Control) human melanoma cells determined by immunoblot analysis are presented B. Expression levels of α-TUBULIN protein are presented as an internal control B. Significantly different (**, p < 0.01) from the control (Si-Control) by Student's t-test. Scale bar, 50 μM.

Mentions: We next examined the function of DTX3L in human G361 melanoma cells. Invasion activity in DTX3L-depleted G361 melanoma cells was about 30% of that in control G361 melanoma cells. Corresponding to the murine melanoma cells, phosphorylation levels of FAK, PI3K and AKT in DTX3L-depleted cells were decreased compared to those in control cells (left Figure 5B). In addition, expression levels of FAK and PI3K in DTX3L-depleted cells were decreased compared to those in control cells, while AKT protein expression levels were comparable in DTX3L-depleted and control cells. Phosphorylation levels of MEK and ERK in DTX3L-depleted and control cells were comparable (right Figure 5B).


Deltex-3-like (DTX3L) stimulates metastasis of melanoma through FAK/PI3K/AKT but not MEK/ERK pathway.

Thang ND, Yajima I, Kumasaka MY, Iida M, Suzuki T, Kato M - Oncotarget (2015)

Decreased cell invasion of DTX3L-depleted human melanoma cellsMatrigel-invasion assay was performed with control (Si-Control) and DTX3L-depleted (Si-DTX3L) G361 human melanoma cells A. Photographs of cells invading the membrane stained with hematoxylin are presented (left). After invading cells had been counted in five random microscopic fields in each Matrigel-invasion assay, the results of three independent assays were normalized and are presented as an invasion index (right). Expression (DTX3L, FAK, PI3K, AKT, MEK and ERK) and phosphorylation (pFAK, pPI3K, pAKT, pMEK and pERK) levels in two kinds of DTX3L-depeleted (Si-DTX3L) and control (Si-Control) human melanoma cells determined by immunoblot analysis are presented B. Expression levels of α-TUBULIN protein are presented as an internal control B. Significantly different (**, p < 0.01) from the control (Si-Control) by Student's t-test. Scale bar, 50 μM.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4546467&req=5

Figure 5: Decreased cell invasion of DTX3L-depleted human melanoma cellsMatrigel-invasion assay was performed with control (Si-Control) and DTX3L-depleted (Si-DTX3L) G361 human melanoma cells A. Photographs of cells invading the membrane stained with hematoxylin are presented (left). After invading cells had been counted in five random microscopic fields in each Matrigel-invasion assay, the results of three independent assays were normalized and are presented as an invasion index (right). Expression (DTX3L, FAK, PI3K, AKT, MEK and ERK) and phosphorylation (pFAK, pPI3K, pAKT, pMEK and pERK) levels in two kinds of DTX3L-depeleted (Si-DTX3L) and control (Si-Control) human melanoma cells determined by immunoblot analysis are presented B. Expression levels of α-TUBULIN protein are presented as an internal control B. Significantly different (**, p < 0.01) from the control (Si-Control) by Student's t-test. Scale bar, 50 μM.
Mentions: We next examined the function of DTX3L in human G361 melanoma cells. Invasion activity in DTX3L-depleted G361 melanoma cells was about 30% of that in control G361 melanoma cells. Corresponding to the murine melanoma cells, phosphorylation levels of FAK, PI3K and AKT in DTX3L-depleted cells were decreased compared to those in control cells (left Figure 5B). In addition, expression levels of FAK and PI3K in DTX3L-depleted cells were decreased compared to those in control cells, while AKT protein expression levels were comparable in DTX3L-depleted and control cells. Phosphorylation levels of MEK and ERK in DTX3L-depleted and control cells were comparable (right Figure 5B).

Bottom Line: Deltex-3-like (DTX3L), an E3 ligase, is a member of the Deltex (DTX) family and is also called B-lymphoma and BAL-associated protein (BBAP).Our analysis in human BRAFV600E inhibitor-resistant melanoma cells showed about 80% decreased invasion in the DTX3L-depleted cells compared to that in the DTX3L-intact cells.Thus, DTX3L is clinically a potential therapeutic target as well as a potential biomarker for melanoma.

View Article: PubMed Central - PubMed

Affiliation: Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai-shi, Aichi, Japan.

ABSTRACT
Deltex-3-like (DTX3L), an E3 ligase, is a member of the Deltex (DTX) family and is also called B-lymphoma and BAL-associated protein (BBAP). Previously, we established RFP/RET-transgenic mice, in which systemic hyperpigmented skin, benign melanocytic tumor(s) and melanoma(s) develop stepwise. Here we showed that levels of Dtx3l/DTX3L in spontaneous melanoma in RFP/RET-transgenic mice and human melanoma cell lines were significantly higher than those in benign melanocytic cells and primarily cultured normal human epithelial melanocytes, respectively. Immunohistochemical analysis of human tissues showed that more than 80% of the melanomas highly expressed DTX3L. Activity of FAK/PI3K/AKT signaling, but not that of MEK/ERK signaling, was decreased in Dtx3l/DTX3L-depleted murine and human melanoma cells. In summary, we demonstrated not only increased DTX3L level in melanoma cells but also DTX3L-mediated regulation of invasion and metastasis in melanoma through FAK/PI3K/AKT but not MEK/ERK signaling. Our analysis in human BRAFV600E inhibitor-resistant melanoma cells showed about 80% decreased invasion in the DTX3L-depleted cells compared to that in the DTX3L-intact cells. Thus, DTX3L is clinically a potential therapeutic target as well as a potential biomarker for melanoma.

No MeSH data available.


Related in: MedlinePlus