High concentration of γ‑H2AX correlates with a marker of apoptotic suppression and PI3K/Akt pathway upregulation in glioblastoma multiforme

Abstract

Glioblastoma multiforme (GBM) is a very aggressive type of primary brain tumor in adults with a poor prognosis. DNA double-strand breaks are known to be associated with the development of numerous cancer types due to their ability to generate genomic instabilities. In GBM, the phosphatidylinositol 3-kinase (PI3K)/Akt pathway is a common pathway that can be activated by exogenous and endogenous factors. Genomic instability may be an endogenous stimulating factor for activation of the PI3K/Akt pathway, which may inhibit the apoptosis of GBM cells. Spontaneous DNA double-strand breaks play an essential role in the survival of GBM cells, and apoptosis levels may reflect survival ability. However, no study has yet been conducted to analyse the association between spontaneous DNA double-strand breaks and apoptosis in patients with GBM prior to treatment. Therefore, the present study examined the concentrations of γ-histone 2AX (γ-H2AX), a sensitive marker of spontaneous DNA double-strand breaks, and cleaved caspase-3, a marker of apoptosis, in patients with GBM. The correlation of γ-H2AX with cleaved caspase-3, PI3K and Akt was also investigated. A total of 26 pre-treatment tumor tissue specimens from patient with GBM were analyzed to determine the concentrations of γ-H2AX, PI3K, Akt and cleaved caspase-3 using sandwich enzyme-linked immunosorbent assays. The results showed a moderate positive correlation between γ-H2AX and PI3K (r=0.52; P=0.007), a moderate positive correlation between γ-H2AX and Akt (r=0.4; P=0.041) and a strong negative correlation between γ-H2AX and cleaved caspase-3 (r=-0.61; P=0.0009). These analyses were also performed in seven tumor tissue specimens from patients with grade I glioma as controls, but no significant correlations were detected. The findings of the present study suggest that a high level of γ-H2AX may affect GBM cell apoptosis via the PI3K/Akt pathway.

Boesenbergia stenophylla-Derived Stenophyllol B Exerts Antiproliferative and Oxidative Stress Responses in Triple-Negative Breast Cancer Cells with Few Side Effects in Normal Cells

“…The state of oxidative stress is a normal phenomenon in cellular functioning, especially during energy production. However, the overexpression of ROS, exceeding the tolerance of redox homeostasis, causes DNA damage [29], such as DNA double-strand breaks (γH2AX) [30,31] and oxidative DNA damage (8-OHdG) [32][33][34]. Consistently, StenBpromoted oxidative stress generates DNA damage (γH2AX and 8-OHdG) (Figures 8 and 9).…”

“…Two types of DNA damage were detected and assessed through antibody-based analyses [47], including markers for DNA double-strand breaks (γH2AX) [30,31] and oxidative DNA damage (8-OHdG) [32,33]. Briefly, 75% ethanol-fixed cells were processed with γH2AX primary antibody/secondary antibody/7AAD (5 µg/mL) treatments [40] or the 8-OHdG primary antibody [47] (Santa Cruz Biotechnology, Santa Cruz, CA, USA) to detect the γH2AX and 8-OHdG levels, respectively.…”