Baicalin is a major component of PC-SPES which inhibits the proliferation of human cancer cells via apoptosis and cell cycle arrest.
BACKGROUND
PC-SPES is an eight-herb mixture that was shown to have activity against prostate cancer. Recently, we isolated a major component (6% of the total ethanolic extract) known as baicalin from PC-SPES by high performance liquid chromatography (HPLC).


METHODS
Baicalin was evaluated for its ability to inhibit clonal growth, and to induce cell cycle arrest of various cancer types (PC-3, DU145, LNCaP prostate cancer cell lines, MCF-7 breast cancer cell line, HL-60 myeloblastic leukemia cell line, and NB4 promyelocytic leukemia cell line). The ability of baicalin to induce apoptosis of cancer cells was examined by both staining with Annexin V and detection of cleavage of Poly (ADP-ribose) polymerase (PARP)(3). Western blot analysis examined the effect of baicalin on levels of p21(waf1) and p27(kip1) in those cells. Futhermore, induction of differentiation in HL-60 cells was measured by expression of CD11b.


RESULTS
Baicalin inhibited the clonal proliferation of LNCaP and PC3 prostate cancer cell lines, and the HL-60 and NB4 myeloblastic/promyelocytic leukemia cell lines with a 50% inhibition (ED(50)) that ranged between 6.4 x 10(-6) to 12 x 10(-6) mol/L. Cell cycle analysis showed that baicalin (2 x 10(-5) mol/L, 4 days) caused a G(0)/G(1) and G(2)/M accumulation of LNCaP and HL-60 cells, respectively. Concomitantly, differentiation and apoptosis were induced in HL-60 cells, as measured by expression of CD11b antigen, staining with annexin V, and detection of cleavage of PARP. Moreover, baicalin enhanced the expression of the cyclin-dependent kinase inhibitor, p27(kip1) in LNCaP and HL-60 cells.


CONCLUSIONS
Baicalin inhibited the proliferation of cancer cells via apoptosis and cell cycle arrest, in which p27(kip1) may play a role. Baicalin may be a novel, adjunctive therapy for selected malignancies including prostate cancer.
Ikezoe
T
T
Division of Hematology/Oncology, UCLA School of Medicine, Los Angeles, California 90048, USA.
Chen
S S
SS
Heber
D
D
Taguchi
H
H
Koeffler
H P
HP
D017304:Annexin A5 / Q000032:analysis; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000096:biosynthesis; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016213:Cyclins / Q000096:biosynthesis; D004354:Drug Screening Assays, Antitumor; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D005260:Female; D005419:Flavonoids / Q000494:pharmacology*; D005434:Flow Cytometry; D018922:HL-60 Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D016177:Macrophage-1 Antigen / Q000032:analysis; D008297:Male; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis
D017304:Annexin A5; D000972:Antineoplastic Agents, Phytogenic; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004365:Drugs, Chinese Herbal; D005419:Flavonoids; D016177:Macrophage-1 Antigen; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; C038044:baicalin