Tyrphostin AG 1024 modulates radiosensitivity in human breast cancer cells
B Wen1, E Deutsch, E Marangoni
1Laboratoire UPRES EA No 27-10 Radiosensibilité-Radiocarcinogénèse Humaine and Unité METSI, Institut Gustave-Roussy, 94805 Villejuif Cédex, France.
Abstract:
Insulin-like growth factor-1 (IGF-1) plays an important growth-promoting effect by activating the PI3K/Akt signalling pathway, inhibiting apoptotic pathways and mediating mitogenic actions. Tyrphostin AG 1024, one selective inhibitor of IGF-1R, was used to evaluate effects on proliferation, radiosensitivity, and radiation-induced cell apoptosis in a human breast cancer cell line MCF-7. Exposure to Tyrphostin AG 1024 inhibited proliferation and induced apoptosis in a time-dependent manner, and the degree of growth inhibition for IC20 plus irradiation (4 Gy) was up to 50% compared to the control. Examination of Tyrphostin AG 1024 effects on radiation response demonstrated a marked enhancement in radiosensitivity and amplification of radiation-induced apoptosis. Western blot analysis indicated that Tyrphostin AG 1024-induced apoptosis was associated with a downregulation of expression of phospho-Akt1, increased expression of Bax, p53 and p21, and a decreased expression of bcl-2 expression, especially when combined with irradiation. To our knowledge, this is the first report showing that an IGF-1 inhibitor was able to markedly increase the response of tumour cells to ionizing radiation. These results suggest that Tyrphostin AG 1024 could be used as a potential therapeutic agent in combination with irradiation.
Insights
Tyrphostin AG 1024, an insulin-like growth factor-1 (IGF-1) inhibitor, enhances cancer cell radiosensitivity and apoptosis. This IGF-1 inhibitor shows potential for combined therapy with irradiation in breast cancer treatment.
Area of Science:
- Oncology
- Molecular Biology
- Radiotherapy
Background:
- Insulin-like growth factor-1 (IGF-1) promotes tumor growth via PI3K/Akt signaling, inhibiting apoptosis and mediating mitogenesis.
- IGF-1 receptor (IGF-1R) is a key mediator of IGF-1 actions in various cancers.
Purpose of the Study:
- To investigate the effects of Tyrphostin AG 1024, a selective IGF-1R inhibitor, on MCF-7 human breast cancer cells.
- To evaluate the impact of Tyrphostin AG 1024 on cell proliferation, radiosensitivity, and radiation-induced apoptosis.
Main Methods:
- MCF-7 cells were treated with Tyrphostin AG 1024 and/or irradiation (4 Gy).
- Cell proliferation, apoptosis, and protein expression (Western blot) were analyzed.
- Key proteins investigated included phospho-Akt1, Bax, p53, p21, and bcl-2.
Main Results:
- Tyrphostin AG 1024 inhibited proliferation and induced apoptosis in a time-dependent manner.
- Combined treatment with Tyrphostin AG 1024 (IC20) and irradiation resulted in up to 50% growth inhibition.
- Enhanced radiosensitivity and amplified radiation-induced apoptosis were observed with Tyrphostin AG 1024 treatment.
- Molecular analysis revealed downregulation of phospho-Akt1 and bcl-2, and upregulation of Bax, p53, and p21, particularly with combined therapy.
Conclusions:
- Tyrphostin AG 1024 significantly enhances the radiosensitivity and apoptotic response of breast cancer cells to ionizing radiation.
- The observed effects are mediated through modulation of the PI3K/Akt pathway and apoptosis-related proteins.
- Tyrphostin AG 1024 represents a promising therapeutic agent for combination with irradiation in breast cancer treatment.
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