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Induction of apoptosis by the bis-Pt(III) complex [Pt(2)(2-mercaptopyrimidine)(4)Cl(2)]
V M González1, M A Fuertes, M J Pérez-Alvarez
1Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain.
Abstract:
We analyzed both the cytotoxicity and the type of cell death produced by the novel binuclear Pt(III) compound Pt-Spym ([Pt(2)(2-mercaptopyrimidine)(4)Cl(2)]) in kidney human fibroblasts and in human tumor cell lines (HeLa, CH1, CH1cisR and HL-60). The data showed that Pt-Spym displayed higher cytotoxicity against these tumor cells than cisplatin. In contrast, Pt-Spym had low toxicity against normal human fibroblasts. Interestingly, Pt-Spym circumvented cisplatin resistance in CH1cisR cells. We also observed that Pt-Spym induced the characteristic changes attributed to apoptosis in cells with normal levels of p53 protein (CH1 and CH1cisR) and with low levels of p53 protein (HeLa), but not in cells lacking p53 (HL-60). Interestingly, Western blot data indicated that apoptosis induction by Pt-Spym in HeLa, CH1, and CH1cisR cells was not associated with drastic changes in p53 levels. However, cis-DDP strongly decreased p53 levels in CH1 and CH1cisR cells and abolish p53 protein in HeLa cells. Altogether, these results suggest that induction of apoptosis by Pt-Spym requires the presence of p53 protein.
Insights
The novel platinum compound Pt-Spym shows higher cytotoxicity against tumor cells than cisplatin and circumvents cisplatin resistance. Apoptosis induction by Pt-Spym requires the presence of p53 protein.
Area of Science:
- Medicinal Chemistry
- Cancer Biology
- Cell Death Mechanisms
Background:
- Cisplatin is a widely used chemotherapy drug, but resistance and toxicity limit its efficacy.
- Novel platinum-based compounds are being investigated to overcome cisplatin resistance and improve therapeutic index.
- Understanding the mechanism of action, including cell death pathways and the role of tumor suppressors like p53, is crucial for developing new anticancer agents.
Purpose of the Study:
- To evaluate the cytotoxicity and cell death induction of the novel binuclear platinum(III) compound, Pt-Spym ([Pt(2)(2-mercaptopyrimidine)(4)Cl(2)]).
- To compare the efficacy and toxicity of Pt-Spym with cisplatin in various human tumor cell lines and normal kidney fibroblasts.
- To investigate the role of p53 protein in mediating apoptosis induced by Pt-Spym.
Main Methods:
- Cytotoxicity assays were performed on human tumor cell lines (HeLa, CH1, CH1cisR, HL-60) and normal human fibroblasts.
- Morphological and biochemical analyses were used to determine the type of cell death induced by Pt-Spym.
- Western blot analysis was employed to assess the levels of p53 protein following treatment with Pt-Spym and cisplatin.
Main Results:
- Pt-Spym exhibited higher cytotoxicity against tumor cells compared to cisplatin.
- Pt-Spym demonstrated low toxicity in normal human fibroblasts.
- Pt-Spym effectively circumvented cisplatin resistance in the CH1cisR cell line.
- Pt-Spym induced apoptosis in cells with normal or low p53 levels but not in p53-deficient cells.
- Apoptosis induction by Pt-Spym was not linked to significant changes in p53 levels, unlike cisplatin which reduced p53 levels.
Conclusions:
- Pt-Spym is a promising anticancer agent with superior efficacy and reduced toxicity compared to cisplatin.
- The mechanism of Pt-Spym-induced apoptosis is dependent on the presence of p53 protein.
- Pt-Spym's ability to bypass cisplatin resistance and its p53-dependent apoptotic pathway warrant further investigation for clinical applications.