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Anticancer effect of tectochrysin in colon cancer cell via suppression of NF-kappaB activity and enhancement of death receptor expression.

Park MH, Hong JE, Park ES, Yoon HS, Seo DW, Hyun BK, Han SB, Ham YW, Hwang BY, Hong JT - Mol. Cancer (2015)

Bottom Line: Flavonoids are a diverse family of natural phenolic compounds commonly found in fruits and vegetables.The expression of DR3, DR4 and Fas were significantly increased, and pro-apoptotic proteins were also increased.A docking model indicated that tectochrysin binds directly to the p50 unit.

View Article: PubMed Central - PubMed

Affiliation: College of Pharmacy and Medical Research Center, Chungbuk National University, 194-31 Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju, Chungbuk, 361-951, Republic of Korea. pmh5205@hanmail.net.

ABSTRACT

Background: Flavonoids are a diverse family of natural phenolic compounds commonly found in fruits and vegetables. Epidemiologic studies showed that flavonoids also reduce the risk of colon cancer. Tectochrysin is one of the major flavonoids of Alpinia oxyphylla Miquel. However, the anti-cancer effects and the molecular mechanisms of tectochrysin in colon cancer cells have not yet been reported. We investigated whether tectochrysin could inhibit colon cancer cell growth at 1, 5, 10 μg/ml. In in vivo study, we injected a tectochrysin treatment dose of 5 mg/kg to each mouse.

Results: Tectochrysin suppressed the growth of SW480 and HCT116 human colon cancer cells. The expression of DR3, DR4 and Fas were significantly increased, and pro-apoptotic proteins were also increased. Tectochrysin treatment also inhibited activity of NF-κB. A docking model indicated that tectochrysin binds directly to the p50 unit. In in vivo, tumor weights and volumes in mice were reduced when treated with tectochrysin. Tectochrysin leads to apoptotic cell death in colon cancer cells through activation of death receptors expression via the inhibition of NF-κB.

Conclusions: Tectochrysin can be a useful agent for the treatment of colon cancer cell growth as well as an adjuvant agent for chemo-resistant cancer cells growth.

No MeSH data available.


Related in: MedlinePlus

Structural interaction between tectochrysin and NF-κB. a Structure of tectochrysin. b Pull-down assay identifies an interaction between the tectochrysin and NF-κB p50. Tectochrysin was conjugated with epoxy-Sepharose 6B as described in Methods. c Docking model of tecotochrysin with NF-κB p50 as described in Methods. d The p50 mutant cells were treated tectochrysin for 24 h, and then analyzed by MTT assay. The data are expressed as the mean ± SD of three experiments. *P < 0.05 compared with the untreated control. #P < 0.05 compared with treated control. e SW480 colon cancer cells were transiently transfected with control or mutant types of p50 for 24 h as described in Methods, and then the cells were treated with tectochrysin for 1 h to determine DNA binding activity of NF-κB. Values below the band are average of band density
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Fig4: Structural interaction between tectochrysin and NF-κB. a Structure of tectochrysin. b Pull-down assay identifies an interaction between the tectochrysin and NF-κB p50. Tectochrysin was conjugated with epoxy-Sepharose 6B as described in Methods. c Docking model of tecotochrysin with NF-κB p50 as described in Methods. d The p50 mutant cells were treated tectochrysin for 24 h, and then analyzed by MTT assay. The data are expressed as the mean ± SD of three experiments. *P < 0.05 compared with the untreated control. #P < 0.05 compared with treated control. e SW480 colon cancer cells were transiently transfected with control or mutant types of p50 for 24 h as described in Methods, and then the cells were treated with tectochrysin for 1 h to determine DNA binding activity of NF-κB. Values below the band are average of band density

Mentions: The interaction of tectochrysin-epoxy Sepharose beads with p50 recombinant protein or cell lysate containing p50 protein was assessed using a pull-down assay. The interaction of tectochrysin-epoxy Sepharose beads with p50 was then detected by immunoblotting with anti-p50 antibody. The results indicated that tectochrysin (Fig. 4a) interacted with recombinant p50 protein or cell lysates containing p50 from SW480 treated with tectochrysin (Fig. 4b). To identify the binding site of tectochrysin to p50, we performed computational docking experiments with tectochrysin and p50. The docking study showed that tectochrysin forms two hydrogen bonds with Gly365 and Val412 of the p50 unit on the amide backbone (binding affinity = -7.6 kcal/mol). It is further surrounded by neighboring hydrophobic amino acid residues such as Val358, Phe353, Ser363, Leu437, and Leu440. Many of these residues are from β-sheets and a loop near DNA binding areas, which may interfere with the DNA binding to the dimeric NF-κB (Fig. 4c). Mutation of Gly365 did not make any difference in binging affinity between tectochrysin and hydrogen bond of p50, but replacing Val412 has a stronger of binding affinity because mutation of this amino acid residue disrupts van Der Waals packing interaction between tectochrysin and p50. Thus, to further determine the direct binding effect of Val412 of p50 with tectochrysin, p50 mutant plasmid (Vp50A) was transfected into SW480, and checked cell growth and NF-κB activity. As expected, tectochrysin did not inhibit the growth of colon cancer cell transfected with mutant p50 (Fig. 4d). EMSA also showed that tectochrysin did not completely inhibit NF-κB activity (Fig. 4e). These results clearly suggested that tectochrysin mediates its effects through binding to Val 412 residue of the p50 subunit of NF-κB.Fig. 4


Anticancer effect of tectochrysin in colon cancer cell via suppression of NF-kappaB activity and enhancement of death receptor expression.

Park MH, Hong JE, Park ES, Yoon HS, Seo DW, Hyun BK, Han SB, Ham YW, Hwang BY, Hong JT - Mol. Cancer (2015)

Structural interaction between tectochrysin and NF-κB. a Structure of tectochrysin. b Pull-down assay identifies an interaction between the tectochrysin and NF-κB p50. Tectochrysin was conjugated with epoxy-Sepharose 6B as described in Methods. c Docking model of tecotochrysin with NF-κB p50 as described in Methods. d The p50 mutant cells were treated tectochrysin for 24 h, and then analyzed by MTT assay. The data are expressed as the mean ± SD of three experiments. *P < 0.05 compared with the untreated control. #P < 0.05 compared with treated control. e SW480 colon cancer cells were transiently transfected with control or mutant types of p50 for 24 h as described in Methods, and then the cells were treated with tectochrysin for 1 h to determine DNA binding activity of NF-κB. Values below the band are average of band density
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Related In: Results  -  Collection

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Fig4: Structural interaction between tectochrysin and NF-κB. a Structure of tectochrysin. b Pull-down assay identifies an interaction between the tectochrysin and NF-κB p50. Tectochrysin was conjugated with epoxy-Sepharose 6B as described in Methods. c Docking model of tecotochrysin with NF-κB p50 as described in Methods. d The p50 mutant cells were treated tectochrysin for 24 h, and then analyzed by MTT assay. The data are expressed as the mean ± SD of three experiments. *P < 0.05 compared with the untreated control. #P < 0.05 compared with treated control. e SW480 colon cancer cells were transiently transfected with control or mutant types of p50 for 24 h as described in Methods, and then the cells were treated with tectochrysin for 1 h to determine DNA binding activity of NF-κB. Values below the band are average of band density
Mentions: The interaction of tectochrysin-epoxy Sepharose beads with p50 recombinant protein or cell lysate containing p50 protein was assessed using a pull-down assay. The interaction of tectochrysin-epoxy Sepharose beads with p50 was then detected by immunoblotting with anti-p50 antibody. The results indicated that tectochrysin (Fig. 4a) interacted with recombinant p50 protein or cell lysates containing p50 from SW480 treated with tectochrysin (Fig. 4b). To identify the binding site of tectochrysin to p50, we performed computational docking experiments with tectochrysin and p50. The docking study showed that tectochrysin forms two hydrogen bonds with Gly365 and Val412 of the p50 unit on the amide backbone (binding affinity = -7.6 kcal/mol). It is further surrounded by neighboring hydrophobic amino acid residues such as Val358, Phe353, Ser363, Leu437, and Leu440. Many of these residues are from β-sheets and a loop near DNA binding areas, which may interfere with the DNA binding to the dimeric NF-κB (Fig. 4c). Mutation of Gly365 did not make any difference in binging affinity between tectochrysin and hydrogen bond of p50, but replacing Val412 has a stronger of binding affinity because mutation of this amino acid residue disrupts van Der Waals packing interaction between tectochrysin and p50. Thus, to further determine the direct binding effect of Val412 of p50 with tectochrysin, p50 mutant plasmid (Vp50A) was transfected into SW480, and checked cell growth and NF-κB activity. As expected, tectochrysin did not inhibit the growth of colon cancer cell transfected with mutant p50 (Fig. 4d). EMSA also showed that tectochrysin did not completely inhibit NF-κB activity (Fig. 4e). These results clearly suggested that tectochrysin mediates its effects through binding to Val 412 residue of the p50 subunit of NF-κB.Fig. 4

Bottom Line: Flavonoids are a diverse family of natural phenolic compounds commonly found in fruits and vegetables.The expression of DR3, DR4 and Fas were significantly increased, and pro-apoptotic proteins were also increased.A docking model indicated that tectochrysin binds directly to the p50 unit.

View Article: PubMed Central - PubMed

Affiliation: College of Pharmacy and Medical Research Center, Chungbuk National University, 194-31 Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju, Chungbuk, 361-951, Republic of Korea. pmh5205@hanmail.net.

ABSTRACT

Background: Flavonoids are a diverse family of natural phenolic compounds commonly found in fruits and vegetables. Epidemiologic studies showed that flavonoids also reduce the risk of colon cancer. Tectochrysin is one of the major flavonoids of Alpinia oxyphylla Miquel. However, the anti-cancer effects and the molecular mechanisms of tectochrysin in colon cancer cells have not yet been reported. We investigated whether tectochrysin could inhibit colon cancer cell growth at 1, 5, 10 μg/ml. In in vivo study, we injected a tectochrysin treatment dose of 5 mg/kg to each mouse.

Results: Tectochrysin suppressed the growth of SW480 and HCT116 human colon cancer cells. The expression of DR3, DR4 and Fas were significantly increased, and pro-apoptotic proteins were also increased. Tectochrysin treatment also inhibited activity of NF-κB. A docking model indicated that tectochrysin binds directly to the p50 unit. In in vivo, tumor weights and volumes in mice were reduced when treated with tectochrysin. Tectochrysin leads to apoptotic cell death in colon cancer cells through activation of death receptors expression via the inhibition of NF-κB.

Conclusions: Tectochrysin can be a useful agent for the treatment of colon cancer cell growth as well as an adjuvant agent for chemo-resistant cancer cells growth.

No MeSH data available.


Related in: MedlinePlus