Factors influencing the cellular accumulation of SN-38 and camptothecin

Jeffrey Cummings, Gary Boyd, Janet S. Macpherson, Helga Wolf, Gillian Smith, John F. Smyth, Duncan I. Jodrell

Research output: Contribution to journalArticle

Abstract

Purpose:
The influence of biophysical factors (drug metabolism, transport proteins, and chemical stability) on the cellular accumulation of camptothecin (CPT) and SN-38 was examined.
Methods:
Drug transporter RNA transcript levels were measured by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Intracellular drug accumulation, metabolism, and drug stability studies were all performed by HPLC.
Results:
A panel of three human cell lines exhibiting different drug resistant phenotypes was investigated. HT29 colon cells glucuronidated SN-38 but did not express P-gp or MRP1 or 2. HCT116 colon cells expressed P-gp and MRP2 but did not catalyse conjugation. A2780 ovarian cells neither catalysed drug metabolism nor contained these drug transporters. In all lines, SN-38 lactone was rapidly taken up achieving peak concentrations at the earliest time point studied (5 min, 3.3–4.1 ng/106 cells). Subsequently, a fall in intracellular lactone concentration occurred, stabilising after 4 h at 0.48–1.18 ng/106 cells. No significant differences in intracellular levels of lactone were observed between the three cell lines with one exception: a twofold increase in HCT116 cells at 24 h. Stability studies in culture medium revealed that SN-38 lactone concentrations disappeared at the same rate regardless of whether cells were present, initially falling to reach equilibrium with the hydroxy acid by 4 h. Indeed, changes in intracellular lactone concentrations followed closely chemical stability profiles in media. Similar patterns of cellular retention and chemical degradation were observed with CPT.
Conclusion:
The major determinant of drug accumulation in three diverse cell line phenotypes was lactone chemical stability in culture medium.
Original languageEnglish
Pages (from-to)194-200
Number of pages7
JournalCancer Chemotherapy and Pharmacology
Volume49
Issue number3
DOIs
Publication statusPublished - 2002
Externally publishedYes

Fingerprint

irinotecan
Camptothecin
Lactones
Pharmaceutical Preparations
Chemical stability
HCT116 Cells
Metabolism
Cells
Cell Line
Culture Media
Colon
Drug Stability
Phenotype
HT29 Cells
Hydroxy Acids
Protein Stability
Reverse Transcriptase Polymerase Chain Reaction
Polymerase chain reaction
RNA-Directed DNA Polymerase
Real-Time Polymerase Chain Reaction

Cite this

Cummings, J., Boyd, G., Macpherson, J. S., Wolf, H., Smith, G., Smyth, J. F., & Jodrell, D. I. (2002). Factors influencing the cellular accumulation of SN-38 and camptothecin. Cancer Chemotherapy and Pharmacology, 49(3), 194-200. https://doi.org/10.1007/s00280-001-0393-3
Cummings, Jeffrey ; Boyd, Gary ; Macpherson, Janet S. ; Wolf, Helga ; Smith, Gillian ; Smyth, John F. ; Jodrell, Duncan I. / Factors influencing the cellular accumulation of SN-38 and camptothecin. In: Cancer Chemotherapy and Pharmacology. 2002 ; Vol. 49, No. 3. pp. 194-200.
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abstract = "Purpose: The influence of biophysical factors (drug metabolism, transport proteins, and chemical stability) on the cellular accumulation of camptothecin (CPT) and SN-38 was examined. Methods: Drug transporter RNA transcript levels were measured by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Intracellular drug accumulation, metabolism, and drug stability studies were all performed by HPLC. Results: A panel of three human cell lines exhibiting different drug resistant phenotypes was investigated. HT29 colon cells glucuronidated SN-38 but did not express P-gp or MRP1 or 2. HCT116 colon cells expressed P-gp and MRP2 but did not catalyse conjugation. A2780 ovarian cells neither catalysed drug metabolism nor contained these drug transporters. In all lines, SN-38 lactone was rapidly taken up achieving peak concentrations at the earliest time point studied (5 min, 3.3–4.1 ng/106 cells). Subsequently, a fall in intracellular lactone concentration occurred, stabilising after 4 h at 0.48–1.18 ng/106 cells. No significant differences in intracellular levels of lactone were observed between the three cell lines with one exception: a twofold increase in HCT116 cells at 24 h. Stability studies in culture medium revealed that SN-38 lactone concentrations disappeared at the same rate regardless of whether cells were present, initially falling to reach equilibrium with the hydroxy acid by 4 h. Indeed, changes in intracellular lactone concentrations followed closely chemical stability profiles in media. Similar patterns of cellular retention and chemical degradation were observed with CPT. Conclusion: The major determinant of drug accumulation in three diverse cell line phenotypes was lactone chemical stability in culture medium.",
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Cummings, J, Boyd, G, Macpherson, JS, Wolf, H, Smith, G, Smyth, JF & Jodrell, DI 2002, 'Factors influencing the cellular accumulation of SN-38 and camptothecin' Cancer Chemotherapy and Pharmacology, vol. 49, no. 3, pp. 194-200. https://doi.org/10.1007/s00280-001-0393-3

Factors influencing the cellular accumulation of SN-38 and camptothecin. / Cummings, Jeffrey; Boyd, Gary; Macpherson, Janet S.; Wolf, Helga; Smith, Gillian; Smyth, John F.; Jodrell, Duncan I.

In: Cancer Chemotherapy and Pharmacology, Vol. 49, No. 3, 2002, p. 194-200.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Factors influencing the cellular accumulation of SN-38 and camptothecin

AU - Cummings, Jeffrey

AU - Boyd, Gary

AU - Macpherson, Janet S.

AU - Wolf, Helga

AU - Smith, Gillian

AU - Smyth, John F.

AU - Jodrell, Duncan I.

PY - 2002

Y1 - 2002

N2 - Purpose: The influence of biophysical factors (drug metabolism, transport proteins, and chemical stability) on the cellular accumulation of camptothecin (CPT) and SN-38 was examined. Methods: Drug transporter RNA transcript levels were measured by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Intracellular drug accumulation, metabolism, and drug stability studies were all performed by HPLC. Results: A panel of three human cell lines exhibiting different drug resistant phenotypes was investigated. HT29 colon cells glucuronidated SN-38 but did not express P-gp or MRP1 or 2. HCT116 colon cells expressed P-gp and MRP2 but did not catalyse conjugation. A2780 ovarian cells neither catalysed drug metabolism nor contained these drug transporters. In all lines, SN-38 lactone was rapidly taken up achieving peak concentrations at the earliest time point studied (5 min, 3.3–4.1 ng/106 cells). Subsequently, a fall in intracellular lactone concentration occurred, stabilising after 4 h at 0.48–1.18 ng/106 cells. No significant differences in intracellular levels of lactone were observed between the three cell lines with one exception: a twofold increase in HCT116 cells at 24 h. Stability studies in culture medium revealed that SN-38 lactone concentrations disappeared at the same rate regardless of whether cells were present, initially falling to reach equilibrium with the hydroxy acid by 4 h. Indeed, changes in intracellular lactone concentrations followed closely chemical stability profiles in media. Similar patterns of cellular retention and chemical degradation were observed with CPT. Conclusion: The major determinant of drug accumulation in three diverse cell line phenotypes was lactone chemical stability in culture medium.

AB - Purpose: The influence of biophysical factors (drug metabolism, transport proteins, and chemical stability) on the cellular accumulation of camptothecin (CPT) and SN-38 was examined. Methods: Drug transporter RNA transcript levels were measured by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Intracellular drug accumulation, metabolism, and drug stability studies were all performed by HPLC. Results: A panel of three human cell lines exhibiting different drug resistant phenotypes was investigated. HT29 colon cells glucuronidated SN-38 but did not express P-gp or MRP1 or 2. HCT116 colon cells expressed P-gp and MRP2 but did not catalyse conjugation. A2780 ovarian cells neither catalysed drug metabolism nor contained these drug transporters. In all lines, SN-38 lactone was rapidly taken up achieving peak concentrations at the earliest time point studied (5 min, 3.3–4.1 ng/106 cells). Subsequently, a fall in intracellular lactone concentration occurred, stabilising after 4 h at 0.48–1.18 ng/106 cells. No significant differences in intracellular levels of lactone were observed between the three cell lines with one exception: a twofold increase in HCT116 cells at 24 h. Stability studies in culture medium revealed that SN-38 lactone concentrations disappeared at the same rate regardless of whether cells were present, initially falling to reach equilibrium with the hydroxy acid by 4 h. Indeed, changes in intracellular lactone concentrations followed closely chemical stability profiles in media. Similar patterns of cellular retention and chemical degradation were observed with CPT. Conclusion: The major determinant of drug accumulation in three diverse cell line phenotypes was lactone chemical stability in culture medium.

U2 - 10.1007/s00280-001-0393-3

DO - 10.1007/s00280-001-0393-3

M3 - Article

VL - 49

SP - 194

EP - 200

JO - Cancer Chemotherapy and Pharmacology

JF - Cancer Chemotherapy and Pharmacology

SN - 0344-5704

IS - 3

ER -