[Effects of Panax notoginseng saponins on proliferation, apoptosis and cell cycle of K562 cells in vitro and the mechanisms].
OBJECTIVE
To investigate the effects of Panax notoginseng saponins (PNS) on the proliferation, apoptosis and cell cycle of K562 cells and explore the molecular mechanisms underlying these effects.


METHODS
PNS-induced growth inhibition of K562 cells was detected by MTT assay; the cell apoptosis was evaluated by AO/EB staining and Annexin V-FITC/ PI staining; flow cytometry was used to detect cell cycle changes in the treated cells. The mRNA expressions of the molecules in mTOR signaling pathway were examined by RT-PCR, and the cellular expressions of cleaved caspeas-3, cyclin D1 and major proteins in mTOR signaling pathway were detected using Western blotting.


RESULTS
MTT assay showed that treatment with 100-800 µg/mL PNS significantly inhibited the proliferation, promoted the cell apoptosis, and caused cell cycle arrest in G0/G1 phase in K562 cells. Western blotting revealed increased protein expression of cleaved caspase-3 and decreased expression of cyclin D1 in PNS-treated cells, in which the proteins expressions of mTOR, p-mTOR, p-p70S6K and p-4E-BP 1 and the mRNA expression of mTOR were all decreased.


CONCLUSIONS
PNS can inhibit the proliferation, induce apoptosis and cause cell cycle arrest in K562 cells possibly by up-regulating cleaved caspase 3 and down-regulating cyclin D1 and mTOR signaling pathway.
Department of Clinical Laboratory Medicine, Bengbu Medical College, Bengbu 233030, China. E-mail: bbmcliyuyun@163.com.
Yuyun
Y
Li
Weiwei
W
Zhai
Xiangrong
X
Yang
Juan
J
Ding
Lixin
L
Kan
D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects*; D059447:Cell Cycle Checkpoints; D049109:Cell Proliferation / Q000187:drug effects*; D019938:Cyclin D1 / Q000378:metabolism; D006801:Humans; D020014:K562 Cells / Q000187:drug effects; D053723:Panax notoginseng / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry*; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D015854:Up-Regulation
C530104:CCND1 protein, human; D012503:Saponins; D019938:Cyclin D1; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; C505407:CASP3 protein, human; D053148:Caspase 3