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Aminopeptidase N (APN)/CD13 inhibitor, Ubenimex, enhances radiation sensitivity in human cervical cancer.

Tsukamoto H, Shibata K, Kajiyama H, Terauchi M, Nawa A, Kikkawa F - BMC Cancer (2008)

Bottom Line: Moreover, we investigated the effect of combining Ubenimex and low-dose radiation on tumor growth using nude mice.In colony formation assays, a significant decline in clonogenic survival was observed in Ubenimex-treated cells.Mice treated with a combination of radiation and Ubenimex showed a significant prolongation of the tumor-doubling time compared with the control, Ubenimex, or radiation-alone groups.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Japan. shiba@med.nagoya-u.ac.jp. tukamoto@med.nagoya-u.a

ABSTRACT

Background: Radiotherapy can be used to treat all stages of cervical cancer. For improving local control via radiotherapy, it is important to use additional antitumor agents. Aminopeptidase N (APN)/CD13, a 150-kDa metalloproteinase, is a multifunctional cell surface aminopeptidase with ubiquitous expression. Recent studies have suggested that APN/CD13 plays an important role in tumor progression in several human malignancies.

Methods: We investigated whether the suppression of APN/CD13 using Ubenimex, an inhibitor of APN/CD13 activity, may affect tumor radiosensitivity in cervical cancer cells both in vitro and in vivo. Cell surface APN/CD13 activity in HeLa cells was calculated using alanine-p-nitroanilido as a substrate. For colony formation assays, single-dose radiation and/or Ubenimex were administered to each dish of HeLa cells, and these dishes were cultured for 14 days. Molecular changes of apoptosis were determined by Western blot. Apoptosis was evaluated by Annexin-V PI staining (flow cytometry analysis) and the Tunel method. Moreover, we investigated the effect of combining Ubenimex and low-dose radiation on tumor growth using nude mice.

Results: We demonstrated that Ubenimex enhanced the effectiveness of radiotherapy, acting as a radiosensitizer both in vitro and in vivo. In colony formation assays, a significant decline in clonogenic survival was observed in Ubenimex-treated cells. Mice treated with a combination of radiation and Ubenimex showed a significant prolongation of the tumor-doubling time compared with the control, Ubenimex, or radiation-alone groups. We also showed that ubenimex enhanced radiation-induced apoptosis in vitro and in vivo.

Conclusion: Although further studies are needed, this report suggests that Ubeniemx acts as a radiosensitizer in cervical cancer treatment, and that the inhibition of APN/CD13 activity may represent a new approach for improving the therapeutic efficacy of radiotherapy for uterine cervical cancer.

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Clonogenic survival of HeLa cells with or without 100 μg/ml Ubenimex. Colonies were counted 14 days after radiation. Errors bar represent the standard error of the mean.
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Figure 2: Clonogenic survival of HeLa cells with or without 100 μg/ml Ubenimex. Colonies were counted 14 days after radiation. Errors bar represent the standard error of the mean.

Mentions: As radiation increased APN/CD13 activity, we investigated the potential of Ubenimex to act as a radiosensitizer. HeLa cells were pretreated with 100 μg/ml Ubenimex for 24 h, irradiated with 2–14 Gy, and then plated in a 14-day clonogenic assay. The survival curves obtained for radiation alone and Ubenimex-treated cells in combination with irradiation are shown in Fig. 2. A significant decline in clonogenic survival was observed in Ubenimex treated cells in combination with radiation of 14 Gy (p < 0.05).


Aminopeptidase N (APN)/CD13 inhibitor, Ubenimex, enhances radiation sensitivity in human cervical cancer.

Tsukamoto H, Shibata K, Kajiyama H, Terauchi M, Nawa A, Kikkawa F - BMC Cancer (2008)

Clonogenic survival of HeLa cells with or without 100 μg/ml Ubenimex. Colonies were counted 14 days after radiation. Errors bar represent the standard error of the mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2289833&req=5

Figure 2: Clonogenic survival of HeLa cells with or without 100 μg/ml Ubenimex. Colonies were counted 14 days after radiation. Errors bar represent the standard error of the mean.
Mentions: As radiation increased APN/CD13 activity, we investigated the potential of Ubenimex to act as a radiosensitizer. HeLa cells were pretreated with 100 μg/ml Ubenimex for 24 h, irradiated with 2–14 Gy, and then plated in a 14-day clonogenic assay. The survival curves obtained for radiation alone and Ubenimex-treated cells in combination with irradiation are shown in Fig. 2. A significant decline in clonogenic survival was observed in Ubenimex treated cells in combination with radiation of 14 Gy (p < 0.05).

Bottom Line: Moreover, we investigated the effect of combining Ubenimex and low-dose radiation on tumor growth using nude mice.In colony formation assays, a significant decline in clonogenic survival was observed in Ubenimex-treated cells.Mice treated with a combination of radiation and Ubenimex showed a significant prolongation of the tumor-doubling time compared with the control, Ubenimex, or radiation-alone groups.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Japan. shiba@med.nagoya-u.ac.jp. tukamoto@med.nagoya-u.a

ABSTRACT

Background: Radiotherapy can be used to treat all stages of cervical cancer. For improving local control via radiotherapy, it is important to use additional antitumor agents. Aminopeptidase N (APN)/CD13, a 150-kDa metalloproteinase, is a multifunctional cell surface aminopeptidase with ubiquitous expression. Recent studies have suggested that APN/CD13 plays an important role in tumor progression in several human malignancies.

Methods: We investigated whether the suppression of APN/CD13 using Ubenimex, an inhibitor of APN/CD13 activity, may affect tumor radiosensitivity in cervical cancer cells both in vitro and in vivo. Cell surface APN/CD13 activity in HeLa cells was calculated using alanine-p-nitroanilido as a substrate. For colony formation assays, single-dose radiation and/or Ubenimex were administered to each dish of HeLa cells, and these dishes were cultured for 14 days. Molecular changes of apoptosis were determined by Western blot. Apoptosis was evaluated by Annexin-V PI staining (flow cytometry analysis) and the Tunel method. Moreover, we investigated the effect of combining Ubenimex and low-dose radiation on tumor growth using nude mice.

Results: We demonstrated that Ubenimex enhanced the effectiveness of radiotherapy, acting as a radiosensitizer both in vitro and in vivo. In colony formation assays, a significant decline in clonogenic survival was observed in Ubenimex-treated cells. Mice treated with a combination of radiation and Ubenimex showed a significant prolongation of the tumor-doubling time compared with the control, Ubenimex, or radiation-alone groups. We also showed that ubenimex enhanced radiation-induced apoptosis in vitro and in vivo.

Conclusion: Although further studies are needed, this report suggests that Ubeniemx acts as a radiosensitizer in cervical cancer treatment, and that the inhibition of APN/CD13 activity may represent a new approach for improving the therapeutic efficacy of radiotherapy for uterine cervical cancer.

Show MeSH
Related in: MedlinePlus