Molecular changes to HeLa cells on continuous exposure to cisplatin or paclitaxel.
OBJECTIVE
To achieve a reversal of multidrug resistance (MDR) in cancer chemotherapy, it is crucial to clarify the characteristics of MDR cells generated by various types of chemotherapeutic agents and to find novel targets.


METHODS
Cisplatin- and paclitaxel-resistant HeLa sublines (HeLa/CDDP and HeLa/TXL, respectively) were established by continuous exposure and their cellular changes were examined based on growth inhibition assays, the transport activity of P-glycoprotein/MDR1, and a RT-PCR analysis of MDR-related factors.


RESULTS
HeLa/CDDP cells showed cross-resistance to platinum derivatives, whereas HeLa/TXL cells were resistant to a variety of MDR1 substrates. Transport activity of MDR1 was reduced in HeLa/CDDP cells and the expression of MDR1 was significantly accelerated in HeLa/TXL cells, compared with HeLa cells. In addition, the expression levels of MDR-related transporters (MRP1-5 or BCRP), betatubulin which is a target for taxanes, and apoptosis-regulated factors were comparable among the three cell lines. On the other hand, the mRNA levels of gamma-glutamyl transferase, but not gamma-glutamyl cysteine synthetase, were higher in HeLa/CDDP cells than in HeLa and HeLa/TXL cells.


CONCLUSIONS
HeLa/CDDP cells showed decreased activity and expression of MDR1 and overexpression of gamma-GT but not gamma-GCS whereas the activity of MDR1 in HeLa/TXL cells was significantly enhanced. Thus, the molecular changes to HeLa cells caused by continuous exposure to cisplatin or paclitaxel were in part clarified, and therefore an understanding of the cellular changes induced by chemotherapeutic agents will be necessary to establish a strategy for reversing MDR.
Department of Hospital Pharmacy, Faculty of Pharmaceutical Sciences, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, 607-8414, Kyoto, Japan. takara@mb.kyoto-phu.ac.jp
Kohji
K
Takara
Yukihisa
Y
Obata
Eri
E
Yoshikawa
Noriaki
N
Kitada
Toshiyuki
T
Sakaeda
Noriaki
N
Ohnishi
Teruyoshi
T
Yokoyama
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000970:Antineoplastic Agents / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D016572:Cyclosporine / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics; D005721:Glutamate-Cysteine Ligase / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics; D009363:Neoplasm Proteins / Q000235:genetics; D017239:Paclitaxel / Q000494:pharmacology*; D000077297:Pregnane X Receptor; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014404:Tubulin / Q000235:genetics; D051028:bcl-2-Associated X Protein / Q000235:genetics; D005723:gamma-Glutamyltransferase / Q000235:genetics
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D002945:Cisplatin; D016572:Cyclosporine; D005721:Glutamate-Cysteine Ligase; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D017239:Paclitaxel; D000077297:Pregnane X Receptor; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011987:Receptors, Steroid; D014404:Tubulin; D051028:bcl-2-Associated X Protein; D005723:gamma-Glutamyltransferase; C116614:ABCG2 protein, human