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Interferon-alpha inhibits cyclooxygenase-1 and stimulates cyclooxygenase-2 expression in bladder cancer cells in
P J Boström1, P Uotila, P Rajala
1Department of Surgery, Turku University Central Hospital, Turku, Finland.
Abstract:
The enzymes cyclooxygenase-1 (Cox-1) and cyclooxygenase-2 (Cox-2) catalyze the initial step in the formation of prostaglandins (PGs). PGs are known to be involved in numerous processes, for example inflammation, immune responses, carcinogenesis, and tumor angiogenesis. The formation of PGs is stimulated in various cancers since the expression of Cox-2 is upregulated. Interferon (IFN)-alpha is used in the treatment of bladder cancer, although not all of the effects of such treatment are thoroughly known. Therefore, we investigated the expression of cyclooxygenases in two bladder cancer cell lines, 5637 and T24, under basal conditions and in the presence of human recombinant IFN-alpha (100, 1,000, and 10,000 U/ml). The mRNA of Cox-1 and Cox-2 was expressed in both cultured bladder carcinoma cell lines. The level of Cox-1 expression was low in 5637 cells and higher in T24 cells. In contrast, Cox-2 expression was prominent in 5637 cells and low in T24 cancer cells. The highest IFN-alpha concentration (10,000 U/ml) decreased the expression of Cox-1 to 47 and 28% of the control levels in 5637 and T24 cells, respectively. In contrast, Cox-2 expression increased in both cell lines. In 5,637 cells, Cox-2 expression increased 1.3-fold with 10,000 U/ml of IFN-alpha. In T24 cells, the maximum effect was achieved by 1,000 U/ml of IFN-alpha, which increased the expression of Cox-2 up to 2.4-fold. These findings may have relevance in the outcome of patients treated with IFN-alpha because upregulated Cox-2 expression may suppress the cell-mediated defense system. On the other hand, the inhibition of Cox-1 could be beneficial because Cox-1 is known to stimulate angiogenesis.
Insights
Interferon-alpha (IFN-alpha) alters cyclooxygenase (Cox) enzyme expression in bladder cancer cells. While IFN-alpha inhibits Cox-1, it upregulates Cox-2, potentially impacting cancer treatment outcomes.
Area of Science:
- Oncology
- Immunology
- Biochemistry
Background:
- Cyclooxygenase enzymes (Cox-1 and Cox-2) are key in prostaglandin synthesis, influencing inflammation, immune responses, and cancer.
- Cyclooxygenase-2 (Cox-2) is often upregulated in cancers, potentially promoting tumor growth and angiogenesis.
- Interferon-alpha (IFN-alpha) is a treatment for bladder cancer, but its precise molecular effects, particularly on Cox enzymes, require further elucidation.
Purpose of the Study:
- To investigate the impact of human recombinant IFN-alpha on the expression of Cox-1 and Cox-2 in two human bladder cancer cell lines (5637 and T24).
- To understand how different concentrations of IFN-alpha affect the mRNA levels of Cox-1 and Cox-2 in these cell lines.
Main Methods:
- Cultured human bladder cancer cell lines (5637 and T24) were treated with varying concentrations of human recombinant IFN-alpha (100, 1,000, and 10,000 U/ml).
- Messenger RNA (mRNA) expression levels of Cox-1 and Cox-2 were analyzed under basal conditions and after IFN-alpha treatment.
Main Results:
- Both Cox-1 and Cox-2 mRNA were expressed in 5637 and T24 cells.
- Cox-1 expression was lower in 5637 cells and higher in T24 cells; IFN-alpha significantly decreased Cox-1 expression in both cell lines at the highest concentration.
- Cox-2 expression was prominent in 5637 cells and low in T24 cells; IFN-alpha treatment led to increased Cox-2 expression in both cell lines, with varying dose-dependency.
Conclusions:
- IFN-alpha differentially regulates Cox-1 and Cox-2 expression in bladder cancer cells.
- The observed upregulation of Cox-2 by IFN-alpha may have implications for the efficacy of IFN-alpha therapy, potentially by suppressing the cell-mediated immune response.
- The inhibition of Cox-1 by IFN-alpha could be a beneficial effect, given Cox-1's role in promoting angiogenesis.