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The 15kDa selenoprotein and thioredoxin reductase 1 promote colon cancer by different pathways.

Tsuji PA, Carlson BA, Yoo MH, Naranjo-Suarez S, Xu XM, He Y, Asaki E, Seifried HE, Reinhold WC, Davis CD, Gladyshev VN, Hatfield DL - PLoS ONE (2015)

Bottom Line: We found that inflammation-related genes regulated by Stat-1, especially interferon-γ-regulated guanylate-binding proteins, were highly elevated in Sep15-deficient, but not in TR1-deficient cells.These results suggest that Sep15 and TR1 participate in interfering regulatory pathways in colon cancer cells.Considering the variable expression levels of Sep15 and TR1 found within the human population, our results provide insights into new roles of selenoproteins in cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Towson University, Towson, Maryland, United States of America.

ABSTRACT
Selenoproteins mediate much of the cancer-preventive properties of the essential nutrient selenium, but some of these proteins have been shown to also have cancer-promoting effects. We examined the contributions of the 15kDa selenoprotein (Sep15) and thioredoxin reductase 1 (TR1) to cancer development. Targeted down-regulation of either gene inhibited anchorage-dependent and anchorage-independent growth and formation of experimental metastases of mouse colon carcinoma CT26 cells. Surprisingly, combined deficiency of Sep15 and TR1 reversed the anti-cancer effects observed with down-regulation of each single gene. We found that inflammation-related genes regulated by Stat-1, especially interferon-γ-regulated guanylate-binding proteins, were highly elevated in Sep15-deficient, but not in TR1-deficient cells. Interestingly, components of the Wnt/β-catenin signaling pathway were up-regulated in cells lacking both TR1 and Sep15. These results suggest that Sep15 and TR1 participate in interfering regulatory pathways in colon cancer cells. Considering the variable expression levels of Sep15 and TR1 found within the human population, our results provide insights into new roles of selenoproteins in cancer.

No MeSH data available.


Related in: MedlinePlus

Expression of Sep15 and TR1 in CT26 cells.Cells were stably transfected with the pU6-m3 control, shSep15, shTR1 or shTR1/shSep15 (as indicated). (A) Expression of Sep15 by real-time RT-PCR (upper panel) and Western blotting (lower panel). (B) Expression of TR1 by real-time RT-PCR (upper panel) and Western blotting (lower panel). (C) Thioredoxin reductase activity. Columns, mean (n = 3–6); bars, SE; (*P<0.05, **P<0.01, compared to control).
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pone.0124487.g001: Expression of Sep15 and TR1 in CT26 cells.Cells were stably transfected with the pU6-m3 control, shSep15, shTR1 or shTR1/shSep15 (as indicated). (A) Expression of Sep15 by real-time RT-PCR (upper panel) and Western blotting (lower panel). (B) Expression of TR1 by real-time RT-PCR (upper panel) and Western blotting (lower panel). (C) Thioredoxin reductase activity. Columns, mean (n = 3–6); bars, SE; (*P<0.05, **P<0.01, compared to control).

Mentions: Mouse colon cancer CT26 cells were stably transfected with shSep15, shTR1, shTR1/shSep15, or the corresponding pU6-m3-(empty vector)-control constructs. We used two shRNA oligonucleotides, and several independent cell clones were chosen for analysis to exclude off-target effects due to the constructs or the transfection process, as published [17,18]. qPCR and Western blotting showed that Sep15 mRNA (Fig 1A, upper panel) and protein levels (Fig 1A, lower panel) were efficiently (>90%) decreased in cells transfected with shSep15 or shTR1/shSep15. qPCR, Western blotting, and catalytic activity assays showed that TR1 mRNA (Fig 1B, upper panel) and protein expression (Fig 1B, lower panel), as well as catalytic activity (Fig 1C) were decreased by >90% in shTR1 and shTR1/shSep15 cells. The mRNA expression of glutathione peroxidases 1 (GPx1) and 2 (GPx2) were not significantly changed, and selenoprotein M (SelM) was only modestly increased in shSep15 (P<0.05) and shTR1/Sep15 cells (P>0.05), as expected (S1 Fig).


The 15kDa selenoprotein and thioredoxin reductase 1 promote colon cancer by different pathways.

Tsuji PA, Carlson BA, Yoo MH, Naranjo-Suarez S, Xu XM, He Y, Asaki E, Seifried HE, Reinhold WC, Davis CD, Gladyshev VN, Hatfield DL - PLoS ONE (2015)

Expression of Sep15 and TR1 in CT26 cells.Cells were stably transfected with the pU6-m3 control, shSep15, shTR1 or shTR1/shSep15 (as indicated). (A) Expression of Sep15 by real-time RT-PCR (upper panel) and Western blotting (lower panel). (B) Expression of TR1 by real-time RT-PCR (upper panel) and Western blotting (lower panel). (C) Thioredoxin reductase activity. Columns, mean (n = 3–6); bars, SE; (*P<0.05, **P<0.01, compared to control).
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Related In: Results  -  Collection

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pone.0124487.g001: Expression of Sep15 and TR1 in CT26 cells.Cells were stably transfected with the pU6-m3 control, shSep15, shTR1 or shTR1/shSep15 (as indicated). (A) Expression of Sep15 by real-time RT-PCR (upper panel) and Western blotting (lower panel). (B) Expression of TR1 by real-time RT-PCR (upper panel) and Western blotting (lower panel). (C) Thioredoxin reductase activity. Columns, mean (n = 3–6); bars, SE; (*P<0.05, **P<0.01, compared to control).
Mentions: Mouse colon cancer CT26 cells were stably transfected with shSep15, shTR1, shTR1/shSep15, or the corresponding pU6-m3-(empty vector)-control constructs. We used two shRNA oligonucleotides, and several independent cell clones were chosen for analysis to exclude off-target effects due to the constructs or the transfection process, as published [17,18]. qPCR and Western blotting showed that Sep15 mRNA (Fig 1A, upper panel) and protein levels (Fig 1A, lower panel) were efficiently (>90%) decreased in cells transfected with shSep15 or shTR1/shSep15. qPCR, Western blotting, and catalytic activity assays showed that TR1 mRNA (Fig 1B, upper panel) and protein expression (Fig 1B, lower panel), as well as catalytic activity (Fig 1C) were decreased by >90% in shTR1 and shTR1/shSep15 cells. The mRNA expression of glutathione peroxidases 1 (GPx1) and 2 (GPx2) were not significantly changed, and selenoprotein M (SelM) was only modestly increased in shSep15 (P<0.05) and shTR1/Sep15 cells (P>0.05), as expected (S1 Fig).

Bottom Line: We found that inflammation-related genes regulated by Stat-1, especially interferon-γ-regulated guanylate-binding proteins, were highly elevated in Sep15-deficient, but not in TR1-deficient cells.These results suggest that Sep15 and TR1 participate in interfering regulatory pathways in colon cancer cells.Considering the variable expression levels of Sep15 and TR1 found within the human population, our results provide insights into new roles of selenoproteins in cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Towson University, Towson, Maryland, United States of America.

ABSTRACT
Selenoproteins mediate much of the cancer-preventive properties of the essential nutrient selenium, but some of these proteins have been shown to also have cancer-promoting effects. We examined the contributions of the 15kDa selenoprotein (Sep15) and thioredoxin reductase 1 (TR1) to cancer development. Targeted down-regulation of either gene inhibited anchorage-dependent and anchorage-independent growth and formation of experimental metastases of mouse colon carcinoma CT26 cells. Surprisingly, combined deficiency of Sep15 and TR1 reversed the anti-cancer effects observed with down-regulation of each single gene. We found that inflammation-related genes regulated by Stat-1, especially interferon-γ-regulated guanylate-binding proteins, were highly elevated in Sep15-deficient, but not in TR1-deficient cells. Interestingly, components of the Wnt/β-catenin signaling pathway were up-regulated in cells lacking both TR1 and Sep15. These results suggest that Sep15 and TR1 participate in interfering regulatory pathways in colon cancer cells. Considering the variable expression levels of Sep15 and TR1 found within the human population, our results provide insights into new roles of selenoproteins in cancer.

No MeSH data available.


Related in: MedlinePlus