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Id3 induces an Elk-1-caspase-8-dependent apoptotic pathway in squamous carcinoma cells.

Chen YS, Aubee J, DiVito KA, Zhou H, Zhang W, Chou FP, Simbulan-Rosenthal CM, Rosenthal DS - Cancer Med (2015)

Bottom Line: Previously, we have found that Id3 induced apoptosis in immortalized human keratinocytes upon UVB exposure, consistent with its role as a tumor suppressor.We found that upon Id3 induction, there was a decrease in cell number under low serum conditions, as well as in soft agar.Using immunofluorescent analysis, we determined that the tumor size decrease was also mediated through apoptosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, District of Columbia, 20057.

No MeSH data available.


Related in: MedlinePlus

(A) A431/Id3 cells in 0.1% FBS were treated with either scrambled or Elk-1 siRNA (siElk-1) for 48 or 72 h and assayed for protein levels. Densitometric quantification of immunoblot showing relative cleaved caspase-8 levels compared to those of GAPDH. (B–D) GFP-expressing A431 Id3 cells were treated with vehicle (B, DMSO), caspase-8 inhibitor (C) or pan-caspase inhibitor (D) in 0.1% FBS. Cell growth was assayed. (E) GFP-expressing A431/Id3 cells treated with either vehicle (DMSO), caspase-8, or pan-caspase inhibitor were grown in agarose and assayed for colony formation after 4 days. (F) SCC4, SCC9, and SCC25 cells were treated with scrambled or Id3 siRNA for 24 h, and assayed for Id3 and caspase-8 levels by immunoblot analysis. SCC, squamous cell carcinoma; FBS, fetal bovine serum. P values ≤ 0.05 are considered statistically significant and represented by asterisks.
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fig03: (A) A431/Id3 cells in 0.1% FBS were treated with either scrambled or Elk-1 siRNA (siElk-1) for 48 or 72 h and assayed for protein levels. Densitometric quantification of immunoblot showing relative cleaved caspase-8 levels compared to those of GAPDH. (B–D) GFP-expressing A431 Id3 cells were treated with vehicle (B, DMSO), caspase-8 inhibitor (C) or pan-caspase inhibitor (D) in 0.1% FBS. Cell growth was assayed. (E) GFP-expressing A431/Id3 cells treated with either vehicle (DMSO), caspase-8, or pan-caspase inhibitor were grown in agarose and assayed for colony formation after 4 days. (F) SCC4, SCC9, and SCC25 cells were treated with scrambled or Id3 siRNA for 24 h, and assayed for Id3 and caspase-8 levels by immunoblot analysis. SCC, squamous cell carcinoma; FBS, fetal bovine serum. P values ≤ 0.05 are considered statistically significant and represented by asterisks.

Mentions: Upon Id3 induction, A431/Id3 cells showed elevated levels of Elk-1, procaspase-8, and active caspase-8 proteins (Fig. 3A). When cells were transfected with Elk-1 siRNA, Id3 induction of Elk-1, procaspase-8, and active caspase-8 were all suppressed (Fig. 3A). This suggests an apoptotic pathway leading from Id3 to Elk1 to procaspase-8 induction and activation in A431 cells.


Id3 induces an Elk-1-caspase-8-dependent apoptotic pathway in squamous carcinoma cells.

Chen YS, Aubee J, DiVito KA, Zhou H, Zhang W, Chou FP, Simbulan-Rosenthal CM, Rosenthal DS - Cancer Med (2015)

(A) A431/Id3 cells in 0.1% FBS were treated with either scrambled or Elk-1 siRNA (siElk-1) for 48 or 72 h and assayed for protein levels. Densitometric quantification of immunoblot showing relative cleaved caspase-8 levels compared to those of GAPDH. (B–D) GFP-expressing A431 Id3 cells were treated with vehicle (B, DMSO), caspase-8 inhibitor (C) or pan-caspase inhibitor (D) in 0.1% FBS. Cell growth was assayed. (E) GFP-expressing A431/Id3 cells treated with either vehicle (DMSO), caspase-8, or pan-caspase inhibitor were grown in agarose and assayed for colony formation after 4 days. (F) SCC4, SCC9, and SCC25 cells were treated with scrambled or Id3 siRNA for 24 h, and assayed for Id3 and caspase-8 levels by immunoblot analysis. SCC, squamous cell carcinoma; FBS, fetal bovine serum. P values ≤ 0.05 are considered statistically significant and represented by asterisks.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4472214&req=5

fig03: (A) A431/Id3 cells in 0.1% FBS were treated with either scrambled or Elk-1 siRNA (siElk-1) for 48 or 72 h and assayed for protein levels. Densitometric quantification of immunoblot showing relative cleaved caspase-8 levels compared to those of GAPDH. (B–D) GFP-expressing A431 Id3 cells were treated with vehicle (B, DMSO), caspase-8 inhibitor (C) or pan-caspase inhibitor (D) in 0.1% FBS. Cell growth was assayed. (E) GFP-expressing A431/Id3 cells treated with either vehicle (DMSO), caspase-8, or pan-caspase inhibitor were grown in agarose and assayed for colony formation after 4 days. (F) SCC4, SCC9, and SCC25 cells were treated with scrambled or Id3 siRNA for 24 h, and assayed for Id3 and caspase-8 levels by immunoblot analysis. SCC, squamous cell carcinoma; FBS, fetal bovine serum. P values ≤ 0.05 are considered statistically significant and represented by asterisks.
Mentions: Upon Id3 induction, A431/Id3 cells showed elevated levels of Elk-1, procaspase-8, and active caspase-8 proteins (Fig. 3A). When cells were transfected with Elk-1 siRNA, Id3 induction of Elk-1, procaspase-8, and active caspase-8 were all suppressed (Fig. 3A). This suggests an apoptotic pathway leading from Id3 to Elk1 to procaspase-8 induction and activation in A431 cells.

Bottom Line: Previously, we have found that Id3 induced apoptosis in immortalized human keratinocytes upon UVB exposure, consistent with its role as a tumor suppressor.We found that upon Id3 induction, there was a decrease in cell number under low serum conditions, as well as in soft agar.Using immunofluorescent analysis, we determined that the tumor size decrease was also mediated through apoptosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, District of Columbia, 20057.

No MeSH data available.


Related in: MedlinePlus