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Increased sensitivity to gemcitabine of P-glycoprotein and multidrug resistance-associated protein-overexpressing human cancer cell lines.

Bergman AM, Pinedo HM, Talianidis I, Veerman G, Loves WJ, van der Wilt CL, Peters GJ - Br. J. Cancer (2003)

Bottom Line: Gemcitabine was tested against human melanoma, non-small-cell lung cancer, small-cell lung cancer, epidermoid carcinoma and ovarian cancer cells with an MDR phenotype as a result of selection by drug exposure or by transfection with the mdr1 gene.In 2R120 and 2R160 cells, dCK activities were seven- and four-fold higher than in SW1573, respectively, which was associated with an increased dCK mRNA and dCK protein.P-glycoprotein and MRP1 overexpression possibly caused a cellular stress resulting in increased gemcitabine metabolism and sensitivity, while reversal of collateral gemcitabine sensitivity by verapamil also suggests a direct relation between the presence of membrane efflux pumps and gemcitabine sensitivity.

View Article: PubMed Central - PubMed

Affiliation: Department Medical Oncology, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands.

ABSTRACT
Gemcitabine (2',2'-difluorodeoxycytidine) is a deoxycytidine analogue that is activated by deoxycytidine kinase (dCK) to its monophosphate and subsequently to its triphosphate dFdCTP, which is incorporated into both RNA and DNA, leading to DNA damage. Multidrug resistance (MDR) is characterised by an overexpression of the membrane efflux pumps P-glycoprotein (P-gP) or multidrug resistance-associated protein (MRP). Gemcitabine was tested against human melanoma, non-small-cell lung cancer, small-cell lung cancer, epidermoid carcinoma and ovarian cancer cells with an MDR phenotype as a result of selection by drug exposure or by transfection with the mdr1 gene. These cell lines were nine- to 72-fold more sensitive to gemcitabine than their parental cell lines. The doxorubicin-resistant cells 2R120 (MRP1) and 2R160 (P-gP) were nine- and 28-fold more sensitive to gemcitabine than their parental SW1573 cells, respectively (P<0.01), which was completely reverted by 25 micro M verapamil. In 2R120 and 2R160 cells, dCK activities were seven- and four-fold higher than in SW1573, respectively, which was associated with an increased dCK mRNA and dCK protein. Inactivation by deoxycytidine deaminase was 2.9- and 2.2-fold decreased in 2R120 and 2R160, respectively. dFdCTP accumulation was similar in SW1573 and its MDR variants after 24 h exposure to 0.1 micro M gemcitabine, but dFdCTP was retained longer in 2R120 (P<0.001) and 2R160 (P<0.003) cells. 2R120 and 2R160 cells also incorporated four- and six-fold more [(3)H]gemcitabine into DNA (P<0.05), respectively. P-glycoprotein and MRP1 overexpression possibly caused a cellular stress resulting in increased gemcitabine metabolism and sensitivity, while reversal of collateral gemcitabine sensitivity by verapamil also suggests a direct relation between the presence of membrane efflux pumps and gemcitabine sensitivity.

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Incorporation of [3H]gemcitabine into DNA relative to incorporation of [14C]thymidine (TdR) into DNA (A) and incorporation of [3H]gemcitabine into RNA relative to incorporation of [3H]uridine (UR) into RNA (B) after 24 h exposure to 0.1 μM (▪) or 1.0 μM () gemcitabine in the human NSCLC cell line SW1573 and its doxorubicin-resistant MDR cell lines; MRP1-overexpressing 2R120 and P-gP-overexpressing 2R160. Values are means±s.d. of at least three experiments. *Statistically significant different from SW1573 cells (t-test, independent samples), P<0.05, **P<0.02. n.d.=not detectable.
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fig4: Incorporation of [3H]gemcitabine into DNA relative to incorporation of [14C]thymidine (TdR) into DNA (A) and incorporation of [3H]gemcitabine into RNA relative to incorporation of [3H]uridine (UR) into RNA (B) after 24 h exposure to 0.1 μM (▪) or 1.0 μM () gemcitabine in the human NSCLC cell line SW1573 and its doxorubicin-resistant MDR cell lines; MRP1-overexpressing 2R120 and P-gP-overexpressing 2R160. Values are means±s.d. of at least three experiments. *Statistically significant different from SW1573 cells (t-test, independent samples), P<0.05, **P<0.02. n.d.=not detectable.

Mentions: When corrected for the inhibition of DNA synthesis, [3H]gemcitabine incorporation into DNA was greater at the higher concentrations in all three cell lines, suggesting that incorporation was concentration dependent (Figure 4Figure 4


Increased sensitivity to gemcitabine of P-glycoprotein and multidrug resistance-associated protein-overexpressing human cancer cell lines.

Bergman AM, Pinedo HM, Talianidis I, Veerman G, Loves WJ, van der Wilt CL, Peters GJ - Br. J. Cancer (2003)

Incorporation of [3H]gemcitabine into DNA relative to incorporation of [14C]thymidine (TdR) into DNA (A) and incorporation of [3H]gemcitabine into RNA relative to incorporation of [3H]uridine (UR) into RNA (B) after 24 h exposure to 0.1 μM (▪) or 1.0 μM () gemcitabine in the human NSCLC cell line SW1573 and its doxorubicin-resistant MDR cell lines; MRP1-overexpressing 2R120 and P-gP-overexpressing 2R160. Values are means±s.d. of at least three experiments. *Statistically significant different from SW1573 cells (t-test, independent samples), P<0.05, **P<0.02. n.d.=not detectable.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2741118&req=5

fig4: Incorporation of [3H]gemcitabine into DNA relative to incorporation of [14C]thymidine (TdR) into DNA (A) and incorporation of [3H]gemcitabine into RNA relative to incorporation of [3H]uridine (UR) into RNA (B) after 24 h exposure to 0.1 μM (▪) or 1.0 μM () gemcitabine in the human NSCLC cell line SW1573 and its doxorubicin-resistant MDR cell lines; MRP1-overexpressing 2R120 and P-gP-overexpressing 2R160. Values are means±s.d. of at least three experiments. *Statistically significant different from SW1573 cells (t-test, independent samples), P<0.05, **P<0.02. n.d.=not detectable.
Mentions: When corrected for the inhibition of DNA synthesis, [3H]gemcitabine incorporation into DNA was greater at the higher concentrations in all three cell lines, suggesting that incorporation was concentration dependent (Figure 4Figure 4

Bottom Line: Gemcitabine was tested against human melanoma, non-small-cell lung cancer, small-cell lung cancer, epidermoid carcinoma and ovarian cancer cells with an MDR phenotype as a result of selection by drug exposure or by transfection with the mdr1 gene.In 2R120 and 2R160 cells, dCK activities were seven- and four-fold higher than in SW1573, respectively, which was associated with an increased dCK mRNA and dCK protein.P-glycoprotein and MRP1 overexpression possibly caused a cellular stress resulting in increased gemcitabine metabolism and sensitivity, while reversal of collateral gemcitabine sensitivity by verapamil also suggests a direct relation between the presence of membrane efflux pumps and gemcitabine sensitivity.

View Article: PubMed Central - PubMed

Affiliation: Department Medical Oncology, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands.

ABSTRACT
Gemcitabine (2',2'-difluorodeoxycytidine) is a deoxycytidine analogue that is activated by deoxycytidine kinase (dCK) to its monophosphate and subsequently to its triphosphate dFdCTP, which is incorporated into both RNA and DNA, leading to DNA damage. Multidrug resistance (MDR) is characterised by an overexpression of the membrane efflux pumps P-glycoprotein (P-gP) or multidrug resistance-associated protein (MRP). Gemcitabine was tested against human melanoma, non-small-cell lung cancer, small-cell lung cancer, epidermoid carcinoma and ovarian cancer cells with an MDR phenotype as a result of selection by drug exposure or by transfection with the mdr1 gene. These cell lines were nine- to 72-fold more sensitive to gemcitabine than their parental cell lines. The doxorubicin-resistant cells 2R120 (MRP1) and 2R160 (P-gP) were nine- and 28-fold more sensitive to gemcitabine than their parental SW1573 cells, respectively (P<0.01), which was completely reverted by 25 micro M verapamil. In 2R120 and 2R160 cells, dCK activities were seven- and four-fold higher than in SW1573, respectively, which was associated with an increased dCK mRNA and dCK protein. Inactivation by deoxycytidine deaminase was 2.9- and 2.2-fold decreased in 2R120 and 2R160, respectively. dFdCTP accumulation was similar in SW1573 and its MDR variants after 24 h exposure to 0.1 micro M gemcitabine, but dFdCTP was retained longer in 2R120 (P<0.001) and 2R160 (P<0.003) cells. 2R120 and 2R160 cells also incorporated four- and six-fold more [(3)H]gemcitabine into DNA (P<0.05), respectively. P-glycoprotein and MRP1 overexpression possibly caused a cellular stress resulting in increased gemcitabine metabolism and sensitivity, while reversal of collateral gemcitabine sensitivity by verapamil also suggests a direct relation between the presence of membrane efflux pumps and gemcitabine sensitivity.

Show MeSH
Related in: MedlinePlus