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Chromatin folding and DNA replication inhibition mediated by a highly antitumor-active tetrazolato-bridged dinuclear platinum(II) complex.

Imai R, Komeda S, Shimura M, Tamura S, Matsuyama S, Nishimura K, Rogge R, Matsunaga A, Hiratani I, Takata H, Uemura M, Iida Y, Yoshikawa Y, Hansen JC, Yamauchi K, Kanemaki MT, Maeshima K - Sci Rep (2016)

Bottom Line: Platinum-based drugs, such as cisplatin, have been used extensively in cancer chemotherapy.The drug-DNA interaction causes DNA crosslinks and subsequent cytotoxicity.Recently, it was reported that an azolato-bridged dinuclear platinum(II) complex, 5-H-Y, exhibits a different anticancer spectrum from cisplatin.

View Article: PubMed Central - PubMed

Affiliation: Biological Macromolecules Laboratory, Structural Biology Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.

ABSTRACT
Chromatin DNA must be read out for various cellular functions, and copied for the next cell division. These processes are targets of many anticancer agents. Platinum-based drugs, such as cisplatin, have been used extensively in cancer chemotherapy. The drug-DNA interaction causes DNA crosslinks and subsequent cytotoxicity. Recently, it was reported that an azolato-bridged dinuclear platinum(II) complex, 5-H-Y, exhibits a different anticancer spectrum from cisplatin. Here, using an interdisciplinary approach, we reveal that the cytotoxic mechanism of 5-H-Y is distinct from that of cisplatin. 5-H-Y inhibits DNA replication and also RNA transcription, arresting cells in the S/G2 phase, and are effective against cisplatin-resistant cancer cells. Moreover, it causes much less DNA crosslinking than cisplatin, and induces chromatin folding. 5-H-Y will expand the clinical applications for the treatment of chemotherapy-insensitive cancers.

No MeSH data available.


Related in: MedlinePlus

DNA damage response in 5-H-Y treated cells.(A) γH2AX foci formation in 5-H-Y or cisplatin-treated HeLa cells. DNA stain, upper; anti-γH2AX antibody staining, lower. Scale bars are 10 μm. The bar graph indicates quantification of the γH2AX signal intensity averaged from ~50 nuclei. Note that the signal in 5-H-Y-treated cells was significantly lower than in cisplatin-treated cells. **p < 0.01, Student’s t-test. (B) Chk1 activation on drug treatment. Western blotting analysis of cell lysates using anti-Chk1 (1st row) and anti-phospho-Chk1 (P-Chk1) (2nd row) antibody. In the 1st row, the position of phosphorylated (activated) Chk1 is marked by the asterisk. Control, no treatment; mitomycin C, mitomycin C treatment for efficient DNA crosslinking. The third row is a loading control using H2B. The values at the bottom indicate quantification of the phosphorylated Chk1 signal intensity. Note that the relative intensity of phosphorylated signal in 5-H-Y-treated cells was considerably lower than that in cisplatin-treated cells. The blots were cropped at the positions of the proteins for clarity and space considerations.
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f3: DNA damage response in 5-H-Y treated cells.(A) γH2AX foci formation in 5-H-Y or cisplatin-treated HeLa cells. DNA stain, upper; anti-γH2AX antibody staining, lower. Scale bars are 10 μm. The bar graph indicates quantification of the γH2AX signal intensity averaged from ~50 nuclei. Note that the signal in 5-H-Y-treated cells was significantly lower than in cisplatin-treated cells. **p < 0.01, Student’s t-test. (B) Chk1 activation on drug treatment. Western blotting analysis of cell lysates using anti-Chk1 (1st row) and anti-phospho-Chk1 (P-Chk1) (2nd row) antibody. In the 1st row, the position of phosphorylated (activated) Chk1 is marked by the asterisk. Control, no treatment; mitomycin C, mitomycin C treatment for efficient DNA crosslinking. The third row is a loading control using H2B. The values at the bottom indicate quantification of the phosphorylated Chk1 signal intensity. Note that the relative intensity of phosphorylated signal in 5-H-Y-treated cells was considerably lower than that in cisplatin-treated cells. The blots were cropped at the positions of the proteins for clarity and space considerations.

Mentions: Next, we examined foci formation of phospho-H2AX (γH2AX) in the 5-H-Y-treated cells, which are often associated with DNA double-strand breaks (DSBs)3334 (Fig. 3A). We observed γH2AX foci in various 5-H-Y-treated cells, such as HeLa, PC9, and TIG-1 cells, but the foci were significantly fewer and weaker than those observed in cisplatin-treated cells (Figs 3A and S5). In addition, in PC9 cells, the γH2AX-foci localization seemed to differ between 5-H-Y- and cisplatin-treated cells: the foci with cisplatin were enriched in the nuclear rim, while those with 5-H-Y were localized more uniformly in the nucleoplasm (Fig. S5). Furthermore, when we examined checkpoint activation by hyperphosphorylation of the checkpoint mediator Chk1 in the 5-H-Y treated cells, significantly lower levels of Chk1 phosphorylation were seen than in cisplatin- or mitomycin C-treated cells (Fig. 3B). These results suggest that DNA damages induced by 5-H-Y are somehow distinct from those by cisplatin.


Chromatin folding and DNA replication inhibition mediated by a highly antitumor-active tetrazolato-bridged dinuclear platinum(II) complex.

Imai R, Komeda S, Shimura M, Tamura S, Matsuyama S, Nishimura K, Rogge R, Matsunaga A, Hiratani I, Takata H, Uemura M, Iida Y, Yoshikawa Y, Hansen JC, Yamauchi K, Kanemaki MT, Maeshima K - Sci Rep (2016)

DNA damage response in 5-H-Y treated cells.(A) γH2AX foci formation in 5-H-Y or cisplatin-treated HeLa cells. DNA stain, upper; anti-γH2AX antibody staining, lower. Scale bars are 10 μm. The bar graph indicates quantification of the γH2AX signal intensity averaged from ~50 nuclei. Note that the signal in 5-H-Y-treated cells was significantly lower than in cisplatin-treated cells. **p < 0.01, Student’s t-test. (B) Chk1 activation on drug treatment. Western blotting analysis of cell lysates using anti-Chk1 (1st row) and anti-phospho-Chk1 (P-Chk1) (2nd row) antibody. In the 1st row, the position of phosphorylated (activated) Chk1 is marked by the asterisk. Control, no treatment; mitomycin C, mitomycin C treatment for efficient DNA crosslinking. The third row is a loading control using H2B. The values at the bottom indicate quantification of the phosphorylated Chk1 signal intensity. Note that the relative intensity of phosphorylated signal in 5-H-Y-treated cells was considerably lower than that in cisplatin-treated cells. The blots were cropped at the positions of the proteins for clarity and space considerations.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4837362&req=5

f3: DNA damage response in 5-H-Y treated cells.(A) γH2AX foci formation in 5-H-Y or cisplatin-treated HeLa cells. DNA stain, upper; anti-γH2AX antibody staining, lower. Scale bars are 10 μm. The bar graph indicates quantification of the γH2AX signal intensity averaged from ~50 nuclei. Note that the signal in 5-H-Y-treated cells was significantly lower than in cisplatin-treated cells. **p < 0.01, Student’s t-test. (B) Chk1 activation on drug treatment. Western blotting analysis of cell lysates using anti-Chk1 (1st row) and anti-phospho-Chk1 (P-Chk1) (2nd row) antibody. In the 1st row, the position of phosphorylated (activated) Chk1 is marked by the asterisk. Control, no treatment; mitomycin C, mitomycin C treatment for efficient DNA crosslinking. The third row is a loading control using H2B. The values at the bottom indicate quantification of the phosphorylated Chk1 signal intensity. Note that the relative intensity of phosphorylated signal in 5-H-Y-treated cells was considerably lower than that in cisplatin-treated cells. The blots were cropped at the positions of the proteins for clarity and space considerations.
Mentions: Next, we examined foci formation of phospho-H2AX (γH2AX) in the 5-H-Y-treated cells, which are often associated with DNA double-strand breaks (DSBs)3334 (Fig. 3A). We observed γH2AX foci in various 5-H-Y-treated cells, such as HeLa, PC9, and TIG-1 cells, but the foci were significantly fewer and weaker than those observed in cisplatin-treated cells (Figs 3A and S5). In addition, in PC9 cells, the γH2AX-foci localization seemed to differ between 5-H-Y- and cisplatin-treated cells: the foci with cisplatin were enriched in the nuclear rim, while those with 5-H-Y were localized more uniformly in the nucleoplasm (Fig. S5). Furthermore, when we examined checkpoint activation by hyperphosphorylation of the checkpoint mediator Chk1 in the 5-H-Y treated cells, significantly lower levels of Chk1 phosphorylation were seen than in cisplatin- or mitomycin C-treated cells (Fig. 3B). These results suggest that DNA damages induced by 5-H-Y are somehow distinct from those by cisplatin.

Bottom Line: Platinum-based drugs, such as cisplatin, have been used extensively in cancer chemotherapy.The drug-DNA interaction causes DNA crosslinks and subsequent cytotoxicity.Recently, it was reported that an azolato-bridged dinuclear platinum(II) complex, 5-H-Y, exhibits a different anticancer spectrum from cisplatin.

View Article: PubMed Central - PubMed

Affiliation: Biological Macromolecules Laboratory, Structural Biology Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.

ABSTRACT
Chromatin DNA must be read out for various cellular functions, and copied for the next cell division. These processes are targets of many anticancer agents. Platinum-based drugs, such as cisplatin, have been used extensively in cancer chemotherapy. The drug-DNA interaction causes DNA crosslinks and subsequent cytotoxicity. Recently, it was reported that an azolato-bridged dinuclear platinum(II) complex, 5-H-Y, exhibits a different anticancer spectrum from cisplatin. Here, using an interdisciplinary approach, we reveal that the cytotoxic mechanism of 5-H-Y is distinct from that of cisplatin. 5-H-Y inhibits DNA replication and also RNA transcription, arresting cells in the S/G2 phase, and are effective against cisplatin-resistant cancer cells. Moreover, it causes much less DNA crosslinking than cisplatin, and induces chromatin folding. 5-H-Y will expand the clinical applications for the treatment of chemotherapy-insensitive cancers.

No MeSH data available.


Related in: MedlinePlus