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[Pilot study of PTEN deletion affecting the expression of Cu/Zn SOD]
1Department of Pathology, Chongqing University of Medical Sciences, Chongqing 400016, China.
Objective:
To investigate whether the deletion of PTEN affects the expression of Cu/Zn SOD and the related biology.
Methods:
Protein and mRNA expression levels of PTEN, P-Akt, Cu/Zn SOD in the control immortalized wild type mouse embryonic fibroblast cells (PTEN+/+) and PTEN-null cells (PTEN-/-) were evaluated by Western blot and Northern blot respectively. The level of superoxide anions were detected using fluorescent probes. The DNA damage was documented by single cell alkalescence gel assay. MTT was used to study the effect of H2O2 on the proliferation of cells.
Results:
The expression of Cu/Zn SOD was down regulated at both protein and mRNA levels, and the level of superoxide anions increased in the PTEN-null cells (PTEN-/-). The phosphorylation level of Akt kinase was up-regulated and the antiproliferative effect of H2O2 decreased in PTEN-/- cells. Furthermore, DNA damage was observed significantly severer in both the blank control and H2O2 treated groups than that in the PTEN+/+ cells.
Conclusions:
Deletion of PTEN affects the expression of Cu/Zn SOD. As a result, reactive oxygen species (ROS) keep at a high level, along with decrease of accumulated oxidative damage and the antiproliferative effect of ROS.
Insights
PTEN deletion downregulates Cu/Zn SOD, increasing reactive oxygen species (ROS). This leads to reduced oxidative damage and diminished antiproliferative effects of ROS, impacting cell biology.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- PTEN (Phosphatase and Tensin homolog) is a critical tumor suppressor.
- PTEN loss is implicated in various cancers.
- The role of PTEN in regulating oxidative stress is not fully understood.
Purpose of the Study:
- To investigate the effect of PTEN deletion on Cu/Zn SOD expression.
- To explore the consequences of altered Cu/Zn SOD levels on cellular oxidative stress and DNA damage.
Main Methods:
- Western blot and Northern blot to assess protein and mRNA levels of PTEN, P-Akt, and Cu/Zn SOD.
- Fluorescent probes for superoxide anion detection.
- Single cell alkaline gel electrophoresis for DNA damage assessment.
- MTT assay to evaluate cell proliferation under hydrogen peroxide (H2O2) stress.
Main Results:
- PTEN deletion resulted in downregulated Cu/Zn SOD at both protein and mRNA levels.
- PTEN-null cells exhibited increased superoxide anion levels and elevated P-Akt.
- Antiproliferative effects of H2O2 were reduced in PTEN-null cells.
- PTEN-null cells showed significantly more severe DNA damage.
Conclusions:
- PTEN deletion significantly impacts Cu/Zn SOD expression.
- Loss of PTEN leads to elevated reactive oxygen species (ROS) levels.
- This dysregulation results in decreased accumulated oxidative damage and reduced cellular response to ROS-induced proliferation inhibition.
