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Thiothymidine combined with UVA as a potential novel therapy for bladder cancer.

Pridgeon SW, Heer R, Taylor GA, Newell DR, O'Toole K, Robinson M, Xu YZ, Karran P, Boddy AV - Br. J. Cancer (2011)

Bottom Line: Addition of raltitrexed (Astra Zeneca, Alderley Edge, Cheshire, UK) increased the incorporation of S(4)TdR into DNA (up to 20-fold at IC(5)) and further sensitised cells to UVA.Cytotoxic effect was associated with crosslinking of DNA, at least partially to protein.Further work is necessary to optimise the delivery of the two components.

View Article: PubMed Central - PubMed

Affiliation: Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle NE2 4HH, UK.

ABSTRACT

Background: Thiothymidine (S(4)TdR) can be incorporated into DNA and sensitise cells to DNA damage and cell death following exposure to UVA light. Studies were performed to determine if the combination of S(4)TdR and UVA could be an effective treatment for bladder cancer.

Methods: Uptake and incorporation of S(4)TdR was determined in rat and human bladder tumour cell lines. Measures of DNA crosslinking and apoptosis were also performed. In vivo activity of the combination of S(4)TdR and UVA was investigated in an orthotopic model of bladder cancer in rats.

Results: Thiothymidine (200 μM) replaced up to 0.63% of thymidine in rat and tumour bladder cancer cells. The combination of S(4)TdR (10-200 μM) and UVA (1-5 kJ m(-2)) caused apoptosis and cell death at doses that were not toxic alone. Addition of raltitrexed (Astra Zeneca, Alderley Edge, Cheshire, UK) increased the incorporation of S(4)TdR into DNA (up to 20-fold at IC(5)) and further sensitised cells to UVA. Cytotoxic effect was associated with crosslinking of DNA, at least partially to protein. Intravenous administration of S(4)TdR, in combination with UVA delivered directly to the bladder, resulted in an antitumour effect in three of five animals treated.

Conclusion: These data indicate that the combination of S(4)TdR and UVA has potential as a treatment for bladder cancer, and give some insight into the mechanism of action. Further work is necessary to optimise the delivery of the two components.

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Related in: MedlinePlus

Caspase 3/7 activity following treatment with S4TdR and UVA. MYU-3L (above) and AY27 (below) cells were cultured in white walled multi-well plates. Cells were treated with 200 μ S4TdR, 10 kJ m−2 UVA or a combination of both; four wells were set up for each treatment group. Twenty-four hours after UVA exposure, 50 μl of Caspase-Glo 3/7 reagent was added to each well and incubated for 1 h at room temperature. Luminescence was measured in a plate reading luminometer. The graphs above represent the mean±s.e.m. of three independent experiments each consisting of four replicates.
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fig5: Caspase 3/7 activity following treatment with S4TdR and UVA. MYU-3L (above) and AY27 (below) cells were cultured in white walled multi-well plates. Cells were treated with 200 μ S4TdR, 10 kJ m−2 UVA or a combination of both; four wells were set up for each treatment group. Twenty-four hours after UVA exposure, 50 μl of Caspase-Glo 3/7 reagent was added to each well and incubated for 1 h at room temperature. Luminescence was measured in a plate reading luminometer. The graphs above represent the mean±s.e.m. of three independent experiments each consisting of four replicates.

Mentions: Twenty-four hours following treatment with 100 μ S4TdR and 10 kJ m−2 UVA, cells appeared shrunken with condensed nuclei. By 18 h after irradiation, caspase 3 and 7 activity in the culture medium was increased by factors of 5.2 and 5.7 for MYU-3L cells and AY27 cells, respectively, compared with controls (Figure 5). The induction of apoptosis was confirmed by flow cytometry analysis. By 18 h after UV irradiation of cells pretreated with 100 μ S4TdR, annexin binding was detectable in 29 and 26% of MYU-3L and AY27 cells, respectively. The corresponding figures for untreated cells were 5 and 7%.


Thiothymidine combined with UVA as a potential novel therapy for bladder cancer.

Pridgeon SW, Heer R, Taylor GA, Newell DR, O'Toole K, Robinson M, Xu YZ, Karran P, Boddy AV - Br. J. Cancer (2011)

Caspase 3/7 activity following treatment with S4TdR and UVA. MYU-3L (above) and AY27 (below) cells were cultured in white walled multi-well plates. Cells were treated with 200 μ S4TdR, 10 kJ m−2 UVA or a combination of both; four wells were set up for each treatment group. Twenty-four hours after UVA exposure, 50 μl of Caspase-Glo 3/7 reagent was added to each well and incubated for 1 h at room temperature. Luminescence was measured in a plate reading luminometer. The graphs above represent the mean±s.e.m. of three independent experiments each consisting of four replicates.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3111209&req=5

fig5: Caspase 3/7 activity following treatment with S4TdR and UVA. MYU-3L (above) and AY27 (below) cells were cultured in white walled multi-well plates. Cells were treated with 200 μ S4TdR, 10 kJ m−2 UVA or a combination of both; four wells were set up for each treatment group. Twenty-four hours after UVA exposure, 50 μl of Caspase-Glo 3/7 reagent was added to each well and incubated for 1 h at room temperature. Luminescence was measured in a plate reading luminometer. The graphs above represent the mean±s.e.m. of three independent experiments each consisting of four replicates.
Mentions: Twenty-four hours following treatment with 100 μ S4TdR and 10 kJ m−2 UVA, cells appeared shrunken with condensed nuclei. By 18 h after irradiation, caspase 3 and 7 activity in the culture medium was increased by factors of 5.2 and 5.7 for MYU-3L cells and AY27 cells, respectively, compared with controls (Figure 5). The induction of apoptosis was confirmed by flow cytometry analysis. By 18 h after UV irradiation of cells pretreated with 100 μ S4TdR, annexin binding was detectable in 29 and 26% of MYU-3L and AY27 cells, respectively. The corresponding figures for untreated cells were 5 and 7%.

Bottom Line: Addition of raltitrexed (Astra Zeneca, Alderley Edge, Cheshire, UK) increased the incorporation of S(4)TdR into DNA (up to 20-fold at IC(5)) and further sensitised cells to UVA.Cytotoxic effect was associated with crosslinking of DNA, at least partially to protein.Further work is necessary to optimise the delivery of the two components.

View Article: PubMed Central - PubMed

Affiliation: Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle NE2 4HH, UK.

ABSTRACT

Background: Thiothymidine (S(4)TdR) can be incorporated into DNA and sensitise cells to DNA damage and cell death following exposure to UVA light. Studies were performed to determine if the combination of S(4)TdR and UVA could be an effective treatment for bladder cancer.

Methods: Uptake and incorporation of S(4)TdR was determined in rat and human bladder tumour cell lines. Measures of DNA crosslinking and apoptosis were also performed. In vivo activity of the combination of S(4)TdR and UVA was investigated in an orthotopic model of bladder cancer in rats.

Results: Thiothymidine (200 μM) replaced up to 0.63% of thymidine in rat and tumour bladder cancer cells. The combination of S(4)TdR (10-200 μM) and UVA (1-5 kJ m(-2)) caused apoptosis and cell death at doses that were not toxic alone. Addition of raltitrexed (Astra Zeneca, Alderley Edge, Cheshire, UK) increased the incorporation of S(4)TdR into DNA (up to 20-fold at IC(5)) and further sensitised cells to UVA. Cytotoxic effect was associated with crosslinking of DNA, at least partially to protein. Intravenous administration of S(4)TdR, in combination with UVA delivered directly to the bladder, resulted in an antitumour effect in three of five animals treated.

Conclusion: These data indicate that the combination of S(4)TdR and UVA has potential as a treatment for bladder cancer, and give some insight into the mechanism of action. Further work is necessary to optimise the delivery of the two components.

Show MeSH
Related in: MedlinePlus