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  • 2010-2014  (2)
  • 1
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2013
    In:  Cancer Research Vol. 73, No. 8_Supplement ( 2013-04-15), p. 983-983
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 73, No. 8_Supplement ( 2013-04-15), p. 983-983
    Abstract: Sunitinib is a multi-targeted receptor tyrosine kinase inhibitor (TKI) and currently approved for use in advanced renal cell carcinoma (RCC). It is really attractive drug for patients who cannot have surgical treatment. However, it is reported that TKI might be substrates of ATP-binding cassette (ABC) transporters, which are able to mediate the efflux of anti-tumor drugs from the tumor cells. In this study, we suggested that inhibition of MDR transporters by elacridar (dual inhibitor of MDR-1 and ABCG2) might overcome sunitinib resistance in experimental RCC. We used 786-O and Caki-1 RCC cell lines. The cells were treated with sunitinib alone, elacridar alone or the combination, then cytotoxicity was measured by the MTT cytotoxicity method. The expression of MDR-1 and ABCG2 mRNA and their protein were detected by real time RT-PCR or Western blotting. Additionally, P-gp function was analyzed by using 99mTc-MIBI. MCF-7 cells were used as negative control for P-gp functional assay. Our results showed that elacridar significantly enhanced sunitinib cytotoxicity in RCC cells. High P-gp expression was especially observed in 786-O, though that of ABCG2 was almost the same among cells. Additionally P-gp assay revealed that the protein would be active and elacridar blocked its function in 786-O, where the accumulation of the 99mTc-MIBI increased 7 folds compared to the control (non-treatment group). These findings suggest that sunitinib resistance is partly mediated by gene and protein expression of MDR transporters. Therefore combination with elacridar could reverse its resistance in MDR sensitive cancer cells, as it did in 786-O. Citation Format: Hiromi Sato, Sana Siddig, Rina Suzuki, Miaki Uzu, Sayumi Suzuki, Yuki Nomura, Yuko Sekine, Tomoya Uehara, Yasushi Arano, Koichi Ueno. A dual inhibitor of MDR-1 and ABCG2,elacridar, enhances cytotoxic effects of sunitinib on RCC cell lines. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 983. doi:10.1158/1538-7445.AM2013-983
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2013
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
    Location Call Number Limitation Availability
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  • 2
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2013
    In:  Cancer Research Vol. 73, No. 8_Supplement ( 2013-04-15), p. 1043-1043
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 73, No. 8_Supplement ( 2013-04-15), p. 1043-1043
    Abstract: Sunitinib (SU) is a multi-targeted receptor tyrosine kinase inhibitor (TKI). It is more effective for renal cell carcinoma (RCC) treatment than conventional immunotherapy, but it causes the resistance and severe side effects in some cases. As a combination therapy might be one solution for them, we paid attention to sodium butyrate (NaBu). It is classified into histone deacetylase (HDAC) inhibitor and it is reported HDAC inhibitors can enhance anti-cancer effect of existent drugs including TKI. So, we examined combination effect of SU and NaBu. And to reveal the target of this combination, we examined effects of SU and NaBu on connexin (Cx), which is a component of gap junction (GJ) and tumor suppressors. We assessed effect of SU and NaBu combination on ACHN (human RCC cell line) cell proliferation by MTT assay and this combination exhibited a synergistic anti-proliferative effect. By real-time PCR, we detected up-regulation of Cx32 mRNA by NaBu. Moreover, NaBu depicted the up-regulated Cx32 protein expression, which was observed by confocal fluorescence microscope. Hemi-channel (Cx hexamer) function was assessed by propidium iodide (PI) uptake into cells. We found both SU and NaBu enhanced PI uptake significantly. GJ function was assessed by scrape-loading. It was confirmed GJ didn't function in ACHN cells and neither SU nor NaBu affected its function. So, it was suggested NaBu could up-regulate Cx32 expression and both SU and NaBu could enhance hemi-channel function. However, we couldn't reveal whether GJ was related to enhancing SU sensitivity. So, we used GJ positive or negative H28 (human malignant mesothelioma cell line) to reveal this matter. As a result, GJ positive cells were more sensitive to SU than negative ones. On the other hand, inhibition of GJ function didn't restore viability of GJ positive cells. In conclusion, we demonstrated the combination therapy of SU and NaBu had synergistic anti-proliferative effect, so it could be a prominent therapy for RCC. Furthermore, we found Cx could be involved in this combination effect, which might be performed in GJ-independent manner. Citation Format: Miaki Uzu, Hiromi Sato, Rina Suzuki, Hiroko Okuzawa, Sana Siddig, Guligena Tuerdi, Sayumi Suzuki, Yuki Nomura, Yuko Sekine, Tomohiro Yano, Koichi Ueno. Connexin might be involved in anti-cancer combination effect of sunitinib and sodium butyrate. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1043. doi:10.1158/1538-7445.AM2013-1043
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2013
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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