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GADD45β Determines Chemoresistance and Invasive Growth of Side Population Cells of Human Embryonic Carcinoma.

Inowa T, Hishikawa K, Matsuzaki Y, Isagawa T, Takeuchi T, Aburatani H, Kitamura T, Fujita T - Stem Cells Int (2010)

Bottom Line: GADD45b was over-expressed in non-SP cells, but the inhibition of GADD45b had no effect on non-SP cells.Paradoxically, the inhibition of GADD45b significantly reduced the viability of NEC8 SP cells.The inhibition of ABCG2, which determines the SP phenotype, had no effect on the invasiveness of NEC8 SP cells, but the inhibition of GADD45b significantly reduced invasiveness.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.

ABSTRACT
Side population (SP) cells are an enriched population of stem, and the existence of SP cells has been reported in human cancer cell lines. In this study, we performed an SP analysis using 11 human cancer cell lines and confirmed the presence of SP cells in an embryonic carcinoma cell line, NEC8. NEC8 SP cells showed characteristics of cancer stem cells, such as high growth rate, chemoresistance and high invasiveness. To further characterize the NEC8 SP cells, we used DNA microarrays. Among 38,500 genes, we identified 12 genes that were over-expressed in SP cells and 1 gene that was over-expressed in non-SP cells. Among these 13 genes, we focused on GADD45b. GADD45b was over-expressed in non-SP cells, but the inhibition of GADD45b had no effect on non-SP cells. Paradoxically, the inhibition of GADD45b significantly reduced the viability of NEC8 SP cells. The inhibition of ABCG2, which determines the SP phenotype, had no effect on the invasiveness of NEC8 SP cells, but the inhibition of GADD45b significantly reduced invasiveness. These results suggest that GADD45b, but not ABCG2, might determine the cancer stem cell-like phenotype, such as chemoresistance and the high invasiveness of NEC8 SP cells, and might be a good therapeutic target.

No MeSH data available.


Related in: MedlinePlus

Functional roles of ABCG2 and GADD45β in NEC8 SP and non-SP cells. (a and b) Quantitative gene expression analysis of ABCG2 and GADD45β after treatment with siRNA in NEC8 SP cells (a) and non-SP cells (b). The white bar represents treatment with nonsilencing control siRNA (NSC) and the black bar represents ABCG2 siRNA and GADD45β siRNA. (c and d) Effect of treatment with siRNA for ABCG2 and GADD45β on cell viability. The white bar represents the untreated control, the gray bar represents treatment with NSC, and the black bar represents treatment with siRNA. The values are shown as the percent of the untreated control. *P < .001 versus NSC.
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fig6: Functional roles of ABCG2 and GADD45β in NEC8 SP and non-SP cells. (a and b) Quantitative gene expression analysis of ABCG2 and GADD45β after treatment with siRNA in NEC8 SP cells (a) and non-SP cells (b). The white bar represents treatment with nonsilencing control siRNA (NSC) and the black bar represents ABCG2 siRNA and GADD45β siRNA. (c and d) Effect of treatment with siRNA for ABCG2 and GADD45β on cell viability. The white bar represents the untreated control, the gray bar represents treatment with NSC, and the black bar represents treatment with siRNA. The values are shown as the percent of the untreated control. *P < .001 versus NSC.

Mentions: To clarify the functional roles of ABCG2 and GADD45β in NEC8 SP cells, we treated the NEC8 SP and non-SP cells with small interfering RNA (siRNA) of the genes and examined cell viability in the presence and absence of cisplatin (0.1 μM). Compared to treatment with nonsilencing control siRNA, treatment with siRNA for ABCG2 and GADD45β significantly reduced gene expression in both NEC8 SP and non-SP cells (Figures 6(a) and 6(b)). Treatment with siRNA for ABCG2, which is overexpressed in NEC8 SP cells, significantly reduced the cell viability of NEC8 SP cells but had no effect on the non-SP cells (Figures 6(c) and 6(d)). Paradoxically, treatment with siRNA for GADD45β, which is overexpressed in non-SP cells, significantly reduced the cell viability of SP cells but had no effect on the non-SP cells (Figures 6(c) and 6(d)).


GADD45β Determines Chemoresistance and Invasive Growth of Side Population Cells of Human Embryonic Carcinoma.

Inowa T, Hishikawa K, Matsuzaki Y, Isagawa T, Takeuchi T, Aburatani H, Kitamura T, Fujita T - Stem Cells Int (2010)

Functional roles of ABCG2 and GADD45β in NEC8 SP and non-SP cells. (a and b) Quantitative gene expression analysis of ABCG2 and GADD45β after treatment with siRNA in NEC8 SP cells (a) and non-SP cells (b). The white bar represents treatment with nonsilencing control siRNA (NSC) and the black bar represents ABCG2 siRNA and GADD45β siRNA. (c and d) Effect of treatment with siRNA for ABCG2 and GADD45β on cell viability. The white bar represents the untreated control, the gray bar represents treatment with NSC, and the black bar represents treatment with siRNA. The values are shown as the percent of the untreated control. *P < .001 versus NSC.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig6: Functional roles of ABCG2 and GADD45β in NEC8 SP and non-SP cells. (a and b) Quantitative gene expression analysis of ABCG2 and GADD45β after treatment with siRNA in NEC8 SP cells (a) and non-SP cells (b). The white bar represents treatment with nonsilencing control siRNA (NSC) and the black bar represents ABCG2 siRNA and GADD45β siRNA. (c and d) Effect of treatment with siRNA for ABCG2 and GADD45β on cell viability. The white bar represents the untreated control, the gray bar represents treatment with NSC, and the black bar represents treatment with siRNA. The values are shown as the percent of the untreated control. *P < .001 versus NSC.
Mentions: To clarify the functional roles of ABCG2 and GADD45β in NEC8 SP cells, we treated the NEC8 SP and non-SP cells with small interfering RNA (siRNA) of the genes and examined cell viability in the presence and absence of cisplatin (0.1 μM). Compared to treatment with nonsilencing control siRNA, treatment with siRNA for ABCG2 and GADD45β significantly reduced gene expression in both NEC8 SP and non-SP cells (Figures 6(a) and 6(b)). Treatment with siRNA for ABCG2, which is overexpressed in NEC8 SP cells, significantly reduced the cell viability of NEC8 SP cells but had no effect on the non-SP cells (Figures 6(c) and 6(d)). Paradoxically, treatment with siRNA for GADD45β, which is overexpressed in non-SP cells, significantly reduced the cell viability of SP cells but had no effect on the non-SP cells (Figures 6(c) and 6(d)).

Bottom Line: GADD45b was over-expressed in non-SP cells, but the inhibition of GADD45b had no effect on non-SP cells.Paradoxically, the inhibition of GADD45b significantly reduced the viability of NEC8 SP cells.The inhibition of ABCG2, which determines the SP phenotype, had no effect on the invasiveness of NEC8 SP cells, but the inhibition of GADD45b significantly reduced invasiveness.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.

ABSTRACT
Side population (SP) cells are an enriched population of stem, and the existence of SP cells has been reported in human cancer cell lines. In this study, we performed an SP analysis using 11 human cancer cell lines and confirmed the presence of SP cells in an embryonic carcinoma cell line, NEC8. NEC8 SP cells showed characteristics of cancer stem cells, such as high growth rate, chemoresistance and high invasiveness. To further characterize the NEC8 SP cells, we used DNA microarrays. Among 38,500 genes, we identified 12 genes that were over-expressed in SP cells and 1 gene that was over-expressed in non-SP cells. Among these 13 genes, we focused on GADD45b. GADD45b was over-expressed in non-SP cells, but the inhibition of GADD45b had no effect on non-SP cells. Paradoxically, the inhibition of GADD45b significantly reduced the viability of NEC8 SP cells. The inhibition of ABCG2, which determines the SP phenotype, had no effect on the invasiveness of NEC8 SP cells, but the inhibition of GADD45b significantly reduced invasiveness. These results suggest that GADD45b, but not ABCG2, might determine the cancer stem cell-like phenotype, such as chemoresistance and the high invasiveness of NEC8 SP cells, and might be a good therapeutic target.

No MeSH data available.


Related in: MedlinePlus