Involvement of GRP78 in the Resistance of Ovarian Carcinoma Cells to Paclitaxel.
BACKGROUND
Glucose regulated protein 78 (GRP78) is a type of molecular chaperone. It is a possible candidate protein that contributes to development of drug resistance. We first examined the involvement of GRP78 in chemotherapy-resistance in human ovarian cancer cell.


METHODS
The expression of GRP78 mRNA and protein were examined by RT-PCR and western blotting, respectively, in human ovarian cancer cells line (HO-8910). Sensitivity of HO-8910 to paclitaxel was determined with methyl thiazolyl tetrazolium (MTT). Suppression of GRP78 expression was performed using specific small-interfering RNA (siRNA) in HO-8910 cells, and cell apoptosis was assessed by flow cytometry. Statistical analysis was performed using the SPSS 15.0 statistical package.


RESULTS
HO-8910 cells, with high basal levels of GRP78, exhibited low sensitivity to paclitaxel. The mRNA and protein levels of GRP78 were dramatically decreased at 24h, 48h and 72h after transfection and the sensitivity to paclitaxel was increased when the GRP78 gene was disturbed by specific siRNA transfection.


CONCLUSIONS
The results suggested that high GRP78 expression might be one of the molecular mechanisms causing resistance to paclitaxel, and therefore siRNA of GRP78 may be useful in tumor-specific gene therapy for ovarian cancer.
Department of Obstetrics and Gynaecology, the Second Affiliated Hospital of Harbin Medical University, Heilongjiang, China E-mail : marschenxin@hotmail.com.
Li-Ying
LY
Zhang
Pei-Ling
PL
Li
Aili
A
Xu
Xin-Chen
XC
Zhang
D000972:Antineoplastic Agents, Phytogenic; D015153:Blotting, Western; D000077216:Carcinoma, Ovarian Epithelial; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D000091342:Endoplasmic Reticulum Chaperone BiP; D005260:Female; D055785:Gene Knockdown Techniques; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009375:Neoplasms, Glandular and Epithelial / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D017239:Paclitaxel; D012333:RNA, Messenger / Q000378:metabolism*; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction
D000972:Antineoplastic Agents, Phytogenic; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017239:Paclitaxel