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Gemcitabine eliminates double minute chromosomes from human ovarian cancer cells.

Yu L, Zhao Y, Quan C, Ji W, Zhu J, Huang Y, Guan R, Sun D, Jin Y, Meng X, Zhang C, Yu Y, Bai J, Sun W, Fu S - PLoS ONE (2013)

Bottom Line: Amplified genes present on the double minute chromosomes are decreased at the DNA level upon gemcitabine treatment.Cells treated with gemcitabine also showed decreased cell growth, colony formation, and invasion.Together, our results suggest that gemcitabine is effective in decreasing double minute chromosomes and this affects the biology of ovarian cancer cells.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.

ABSTRACT
Double minute chromosomes are cytogenetic manifestations of gene amplification frequently seen in cancer cells. Genes amplified on double minute chromosomes include oncogenes and multi-drug resistant genes. These genes encode proteins which contribute to cancer formation, cancer progression, and development of resistance to drugs used in cancer treatment. Elimination of double minute chromosomes, and therefore genes amplified on them, is an effective way to decrease the malignancy of cancer cells. We investigated the effectiveness of a cancer drug, gemcitabine, on the loss of double minute chromosomes from the ovarian cancer cell line UACC-1598. Gemcitabine is able to decrease the number of double minute chromosomes in cells at a 7500X lower concentration than the commonly used cancer drug hydroxyurea. Amplified genes present on the double minute chromosomes are decreased at the DNA level upon gemcitabine treatment. Gemcitabine, even at a low nanomolar concentration, is able to cause DNA damage. The selective incorporation of double minutes chromatin and γ-H2AX signals into micronuclei provides a strong link between DNA damage and the loss of double minute chromosomes from gemcitabine treated cells. Cells treated with gemcitabine also showed decreased cell growth, colony formation, and invasion. Together, our results suggest that gemcitabine is effective in decreasing double minute chromosomes and this affects the biology of ovarian cancer cells.

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Entrapment of EIF5A2, MYCN and MCL1 in MN in UACC-1598 ovarian cancer cell line by growth in HU and GEM.The left two panels are representative pictures of cells showing MN without signal and the right two panels are representative pictures of cells showing MN with EIF5A2/MYCN or MCL1/MYCN signal. MYCN signal is shown in green, EIF5A2 and MCL1 are shown in red, and the overlap is shown in yellow. Arrows indicate MN.
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pone-0071988-g004: Entrapment of EIF5A2, MYCN and MCL1 in MN in UACC-1598 ovarian cancer cell line by growth in HU and GEM.The left two panels are representative pictures of cells showing MN without signal and the right two panels are representative pictures of cells showing MN with EIF5A2/MYCN or MCL1/MYCN signal. MYCN signal is shown in green, EIF5A2 and MCL1 are shown in red, and the overlap is shown in yellow. Arrows indicate MN.

Mentions: One way in which DMs are thought to be eliminated from cells is by incorporation into micronuclei. With amplified genes as probes, we observed some cells with MN containing probes while others have MN not containing the probes (Figure 4). We determined the percentage of MN formation in cells treated with HU or GEM, and also observed whether these micronuclei contained EIF5A2, MYCN and MCL1 signals (Table 1). Vehicle DMSO treated cells have a MN formation frequency of 13.87×10−2 while HU treated cells have a MN formation frequency of 30.61×10−2, indicating HU is effective at inducing MN formation. In addition, GEM is also effective at inducing MN formation. Cells treated with 20 nM GEM have a MN formation frequency of 21.82×10−2 compared to 13.98×10−2 in control cells. Upon examining EIF5A2, MYCN, and MCL signals in the MN, we also noticed an increase in the frequency of MN which contains EIF5A2, MYCN, and MCL signals, designated MN (EIF5A2+ MYCN+ MCL+) or MN (+) for short, for cells in the HU and GEM treatment groups. A 2.57 and 1.81 fold increase in MN (+) frequency was observed for HU and GEM treated cells respectively. Together, our FISH results suggest that DMs amplified genes EIF5A2, MYCN, and MCL are lost from cells treated with either HU or GEM by being selectively entrapped into MN. Similar results were obtained with UACC-1598-4 cells (Table S1).


Gemcitabine eliminates double minute chromosomes from human ovarian cancer cells.

Yu L, Zhao Y, Quan C, Ji W, Zhu J, Huang Y, Guan R, Sun D, Jin Y, Meng X, Zhang C, Yu Y, Bai J, Sun W, Fu S - PLoS ONE (2013)

Entrapment of EIF5A2, MYCN and MCL1 in MN in UACC-1598 ovarian cancer cell line by growth in HU and GEM.The left two panels are representative pictures of cells showing MN without signal and the right two panels are representative pictures of cells showing MN with EIF5A2/MYCN or MCL1/MYCN signal. MYCN signal is shown in green, EIF5A2 and MCL1 are shown in red, and the overlap is shown in yellow. Arrows indicate MN.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3750019&req=5

pone-0071988-g004: Entrapment of EIF5A2, MYCN and MCL1 in MN in UACC-1598 ovarian cancer cell line by growth in HU and GEM.The left two panels are representative pictures of cells showing MN without signal and the right two panels are representative pictures of cells showing MN with EIF5A2/MYCN or MCL1/MYCN signal. MYCN signal is shown in green, EIF5A2 and MCL1 are shown in red, and the overlap is shown in yellow. Arrows indicate MN.
Mentions: One way in which DMs are thought to be eliminated from cells is by incorporation into micronuclei. With amplified genes as probes, we observed some cells with MN containing probes while others have MN not containing the probes (Figure 4). We determined the percentage of MN formation in cells treated with HU or GEM, and also observed whether these micronuclei contained EIF5A2, MYCN and MCL1 signals (Table 1). Vehicle DMSO treated cells have a MN formation frequency of 13.87×10−2 while HU treated cells have a MN formation frequency of 30.61×10−2, indicating HU is effective at inducing MN formation. In addition, GEM is also effective at inducing MN formation. Cells treated with 20 nM GEM have a MN formation frequency of 21.82×10−2 compared to 13.98×10−2 in control cells. Upon examining EIF5A2, MYCN, and MCL signals in the MN, we also noticed an increase in the frequency of MN which contains EIF5A2, MYCN, and MCL signals, designated MN (EIF5A2+ MYCN+ MCL+) or MN (+) for short, for cells in the HU and GEM treatment groups. A 2.57 and 1.81 fold increase in MN (+) frequency was observed for HU and GEM treated cells respectively. Together, our FISH results suggest that DMs amplified genes EIF5A2, MYCN, and MCL are lost from cells treated with either HU or GEM by being selectively entrapped into MN. Similar results were obtained with UACC-1598-4 cells (Table S1).

Bottom Line: Amplified genes present on the double minute chromosomes are decreased at the DNA level upon gemcitabine treatment.Cells treated with gemcitabine also showed decreased cell growth, colony formation, and invasion.Together, our results suggest that gemcitabine is effective in decreasing double minute chromosomes and this affects the biology of ovarian cancer cells.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.

ABSTRACT
Double minute chromosomes are cytogenetic manifestations of gene amplification frequently seen in cancer cells. Genes amplified on double minute chromosomes include oncogenes and multi-drug resistant genes. These genes encode proteins which contribute to cancer formation, cancer progression, and development of resistance to drugs used in cancer treatment. Elimination of double minute chromosomes, and therefore genes amplified on them, is an effective way to decrease the malignancy of cancer cells. We investigated the effectiveness of a cancer drug, gemcitabine, on the loss of double minute chromosomes from the ovarian cancer cell line UACC-1598. Gemcitabine is able to decrease the number of double minute chromosomes in cells at a 7500X lower concentration than the commonly used cancer drug hydroxyurea. Amplified genes present on the double minute chromosomes are decreased at the DNA level upon gemcitabine treatment. Gemcitabine, even at a low nanomolar concentration, is able to cause DNA damage. The selective incorporation of double minutes chromatin and γ-H2AX signals into micronuclei provides a strong link between DNA damage and the loss of double minute chromosomes from gemcitabine treated cells. Cells treated with gemcitabine also showed decreased cell growth, colony formation, and invasion. Together, our results suggest that gemcitabine is effective in decreasing double minute chromosomes and this affects the biology of ovarian cancer cells.

Show MeSH
Related in: MedlinePlus