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  • The Cytotoxicity of Kahweol in HT-29 Human Colorectal Cancer Cells Is Mediated by Apoptosis and Suppression of Heat Shock Protein 70 Expression.

The Cytotoxicity of Kahweol in HT-29 Human Colorectal Cancer Cells Is Mediated by Apoptosis and Suppression of Heat Shock Protein 70 Expression.

Biomolecules & therapeutics (2015-03-15)
Dong Wook Choi, Man Sup Lim, Jae Won Lee, Wanjoo Chun, Sang Hyuk Lee, Yang Hoon Nam, Jin Myung Park, Dae Hee Choi, Chang Don Kang, Sung Joon Lee, Sung Chul Park
ABSTRACT

Although coffee is known to have antioxidant, anti-inflammatory, and antitumor properties, there have been few reports about the effect and mechanism of coffee compounds in colorectal cancer. Heat shock proteins (HSPs) are molecular chaperones that prevent cell death. Their expression is significantly elevated in many tumors and is accompanied by increased cell proliferation, metastasis and poor response to chemotherapy. In this study, we investigated the cytotoxicity of four bioactive compounds in coffee, namely, caffeine, caffeic acid, chlorogenic acid, and kahweol, in HT-29 human colon adenocarcinoma cells. Only kahweol showed significant cytotoxicity. Specifically, kahweol increased the expression of caspase-3, a pro-apoptotic factor, and decreased the expression of anti-apoptotic factors, such as Bcl-2 and phosphorylated Akt. In addition, kahweol significantly attenuated the expression of HSP70. Inhibition of HSP70 activity with triptolide increased kahweol-induced cytotoxicity. In contrast, overexpression of HSP70 significantly reduced kahweol-induced cell death. Taken together, these results demonstrate that kahweol inhibits colorectal tumor cell growth by promoting apoptosis and suppressing HSP70 expression.

MATERIALS
Product Number
Brand
Product Description

Chlorogenic acid, primary reference standard
Supelco
Melting point standard 235-237°C, analytical standard
Sigma-Aldrich
Chlorogenic acid, ≥95% (titration)
Sigma-Aldrich
Triptolide, from Tripterygium wilfordii, ≥98% (HPLC), solid
Caffeine for system suitability, European Pharmacopoeia (EP) Reference Standard
Chlorogenic acid, European Pharmacopoeia (EP) Reference Standard
Supelco
Caffeine, certified reference material, TraceCERT®, Manufactured by: Sigma-Aldrich Production GmbH, Switzerland
Supelco
Caffeine Melting Point Standard, Pharmaceutical Secondary Standard; Certified Reference Material
USP
Caffeine melting point standard, United States Pharmacopeia (USP) Reference Standard
Supelco
Caffeic acid, matrix substance for MALDI-MS, ≥99.0% (HPLC)
Sigma-Aldrich
Caffeine, anhydrous, 99%, FCC, FG
Sigma-Aldrich
Caffeine, anhydrous, tested according to Ph. Eur.
Sigma-Aldrich
Adenosine 5′-diphosphoribose sodium salt, ≥93%
Sigma-Aldrich
Caffeic acid, ≥98.0% (HPLC)
Sigma-Aldrich
Caffeine, meets USP testing specifications, anhydrous
Sigma-Aldrich
Caffeine, Sigma Reference Standard, vial of 250 mg
Sigma-Aldrich
Caffeine, powder, ReagentPlus®
Sigma-Aldrich
Caffeine, BioXtra
Supelco
Mettler-Toledo Calibration substance ME 18872, Caffeine, traceable to primary standards (LGC)
Supelco
Caffeine, Pharmaceutical Secondary Standard; Certified Reference Material
USP
Caffeine, United States Pharmacopeia (USP) Reference Standard
Caffeine, European Pharmacopoeia (EP) Reference Standard