99mTc-sestamibi to monitor treatment with antisense oligodeoxynucleotide complementary to MRP mRNA in human breast cancer cells.

Abstract

OBJECTIVE:

Technetium-99m sestamibi (MIBI) has been utilized to evaluate multi-drug resistance (MDR) phenomenon of malignant tumors and to predict chemotherapeutic effects on them. The current investigation examined the possibility of monitoring changes with respect to mRNA expression of multi-drug resistance associated protein (MRP) following antisense oligodeoxynucleotide (AS-ODN) treatment involving 99mTc-MIBI.

METHODS:

The human breast cancer MCF-7 cell line and its MDR-induced MCF-7/VP cell line were employed. Cell suspensions of the two cell lines at 1 x 10(4) cells/ml were inoculated in 24-well plates (0.2 ml/well) and incubated for one day. Antisense (AS) 20-mer phosphorothioate ODN complementary to the coding region of MRP mRNA and its sense (S) ODN were administered at final concentrations up to 25 microM, followed by a 5-day incubation. 99mTc-MIBI solution was added to each well and incubated for 30 min. Cellular 99mTc-MIBI uptake was corrected for protein concentration. MRP mRNA expression levels were analyzed via the reverse transcription polymerase chain reaction (RT-PCR).

RESULTS:

Cellular uptake of 99mTc-MIBI in MCF-7/VP cells was only 15% of that of MCF-7 cells. Following AS-ODN treatment at 25 microM for five days, 99mTc-MIBI uptake in MCF-7/VP cells increased 2.4-fold in comparison with non-treated control cells. 99mTc-MIBI uptake in MCF-7 cells was unaffected by AS-ODN administration. Sense ODN did not alter uptake in either cell line. RT-PCR confirmed reduction of MRP mRNA in MCF-7/VP cells following AS-ODN treatment.

CONCLUSION:

Effects of AS-ODN administration on MRP function can be monitored via assessment of cellular uptake of 99mTc-MIBI.

• Authors: Seigo Kinuya, Jingming Bai, Kazuhiro Shiba, Kunihiko Yokoyama, Hirofumi Mori, Makoto Fukuoka, Naoto Watanabe, Noriyuki Shuke, Takatoshi Michigishi, Norihisa Tonami
• Journal: Annals of nuclear medicine (Ann Nucl Med) Vol. 20 Issue 1 Pg. 29-34 (Jan 2006) ISSN: 0914-7187 [Print] Japan
• PMID: 16485571 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Multidrug Resistance-Associated Proteins
• Oligodeoxyribonucleotides, Antisense
• RNA, Messenger
• Radiopharmaceuticals
• Technetium Tc 99m Sestamibi

Topics

• Breast Neoplasms (diagnostic imaging, genetics, metabolism, therapy)
• Cell Line, Tumor
• Genetic Therapy (methods)
• Humans
• Metabolic Clearance Rate
• Multidrug Resistance-Associated Proteins (genetics, metabolism)
• Oligodeoxyribonucleotides, Antisense (administration & dosage, genetics)
• Prognosis
• RNA, Messenger (genetics)
• Radionuclide Imaging
• Radiopharmaceuticals (pharmacokinetics)
• Technetium Tc 99m Sestamibi (pharmacokinetics)
• Treatment Outcome