[Effects of RNA interference targeting hypoxia-inducible factor-1alpha (HIF-1alpha) on chemosensitivity of leukemia K562 cells towards homoharringtonine].
OBJECTIVE
Hypoxia-inducible factor-1alpha (HIF-1alpha) is a key transcription factor under anoxic circumstances. Little is known about changes in biological characters of hematological malignancies, especially leukemia. This study was to explore the influence of RNA interference (RNAi) targeting HIF-1alpha on sensitivity of human chronic myelogeneous leukemia (CML) K562 cells towards homoharringtonine (HHT).


METHODS
HIF-1alpha short hairpin RNA (shRNA) was constructed using pSilencer 2.1-U6 hygro vector and transfected into K562 cells. Positive clones were screened using hygromycin. After inhibition of HIF-1alpha, expressions of its target genes such as vascular endothelial growth factor (VEGF), glucose transporter-1 (Glut-1), phosphoglycerate kinase (PGK), and P-glycoprotein (P-gp) were detected by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Sensitivity of K562 cells to HHT was detected by MTT assay.


RESULTS
HIF-1alpha expression was inhibited at both mRNA and protein levels after transfection of RNAi HIF-1alpha, which subsequently caused a dramatic decrease in VEGF, Glut-1, PGK, and P-gp under hypoxic conditions. In addition, HIF-1alpha inhibition was found to increase drug sensitivity of K562 cells to HHT.


CONCLUSIONS
HIF-1alpha inhibition may result in a decrease of genes related to angiogenesis and glycolysis metabolism and an increase of drug sensitivity to HHT in K562 cells.
Li
Bing-Zong
BZ
Department of Hematology, The Second Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215004, P R China.
Zhuang
Wen-Zhuo
WZ
Chen
Ping
P
Fu
Jin-Xiang
JX
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D001483:Base Sequence; D051272:Glucose Transporter Type 1 / Q000096:biosynthesis; D006248:Harringtonines / Q000494:pharmacology*; D000077863:Homoharringtonine; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000037:antagonists & inhibitors* / Q000235:genetics; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy* / Q000378:metabolism; D008969:Molecular Sequence Data; D034622:RNA Interference; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D000972:Antineoplastic Agents, Phytogenic; D051272:Glucose Transporter Type 1; C497442:HIF1A protein, human; D006248:Harringtonines; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; D000077863:Homoharringtonine