Korean red ginseng extract induces apoptosis and decreases telomerase activity in human leukemia cells.
OBJECTIVE
Korean red ginseng (KRG, Panax ginseng C.A. Meyer Radix rubra) has been used to treat various diseases including cancer. However, the molecular mechanisms responsible for KRG extract induced apoptosis and telomerase inhibition remain unclear.


METHODS
The hot water extract from KRG was used to evaluate the mechanism of induction of apoptosis in U937 human leukemia cells and its effects on cyclooxgenase-2 (COX-2) and telomerase activity.


RESULTS
KRG extract treatment to U937 cells resulted in growth inhibition and induction of apoptosis in a concentration-dependent manner as measured by hemacytometer counts, MTT assay, fluorescence microscopy, agarose gel electrophoresis and flow cytometry analysis. The increase in apoptosis was associated with the down-regulation of antiapoptotic Bcl-2, Bcl-X(L), and IAPs family members, and the activation of caspase-3. KRG extract treatment also decreased the expression levels of COX-2 and inducible nitric oxide synthase. Furthermore, KRG extract treatment progressively down-regulated the expression of human telomerase reverse transcriptase, a main determinant of the telomerase enzymatic activity, with inhibiting the expression of c-Myc in a concentration-dependent manner.


CONCLUSIONS
These results provide important new insights into the possible molecular mechanisms of the anticancer activity of KRG extract.
Park
Sang Eun
SE
Department of Pharmacy (BK21 Program), Research Institute for Drug Development, Pusan National University, Busan 609-735, Republic of Korea.
Park
Cheol
C
Kim
Sun Hee
SH
Hossain
Mohammad Akbar
MA
Kim
Min Young
MY
Chung
Hae Young
HY
Son
Woo Sung
WS
Kim
Gi-Young
GY
Choi
Yung Hyun
YH
Kim
Nam Deuk
ND
D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D051546:Cyclooxygenase 2 / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004587:Electrophoresis, Agar Gel; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy / Q000378:metabolism; D055670:Medicine, Korean Traditional; D008856:Microscopy, Fluorescence; D005894:Panax / Q000737:chemistry*; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D016271:Proto-Oncogene Proteins c-myc / Q000187:drug effects; D019098:Telomerase / Q000187:drug effects* / Q000378:metabolism; D020298:U937 Cells
D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts; D016271:Proto-Oncogene Proteins c-myc; D051546:Cyclooxygenase 2; D019098:Telomerase