SIRT6 suppresses glioma cell growth via induction of apoptosis, inhibition of oxidative stress and suppression of JAK2/STAT3 signaling pathway activation

Abstract

Sirtuin 6 (SIRT6) is a member of the mammalian NAD+‑dependent deacetylase sirtuin family that acts to maintain genomic stability and to repress genes. SIRT6 has recently been reported to be a tumor suppressor that controls cancer metabolism, although this effect of SIRT6 is still in dispute. Moreover, the role of SIRT6 in glioma is largely unknown. In the present study, we found that overexpression of SIRT6 using an adenovirus inhibited glioma cell growth and induced marked cell injury in two glioma cell lines (U87‑MG and T98G). Fluorescent terminal deoxyribonucleotidyl transferase (TdT)‑mediated biotin‑16‑dUTP nick‑end labelling (TUNEL) assay showed that SIRT6 overexpression induced obvious apoptosis in the T98G glioma cells. Immunoblotting and immunofluorescent staining demonstrated that SIRT6 overexpression promoted the mitochondrial-to‑nuclear translocation of apoptosis‑inducing factor (AIF), a potent apoptosis inducer. Moreover, we found that SIRT6 overexpression largely reduced oxidative stress and suppressed the activation of the JAK2/STAT3 signaling pathway in glioma cells. Finally, we showed that SIRT6 mRNA and protein levels in human glioblastoma multiforme tissues were significantly lower than the levels in peritumor tissues. In summary, our data suggest that SIRT6 suppresses glioma cell growth via induction of apoptosis, inhibition of oxidative stress and inhibition of the activation of the JAK2/STAT3 signaling pathway. These results indicate that SIRT6 may be a promising therapeutic target for glioma treatment.

Inhibitor of Nicotinamide Phosphoribosyltransferase Sensitizes Glioblastoma Cells to Temozolomide via Activating ROS/JNK Signaling Pathway

“…Briefly, cells were cultured with Dulbecco's Modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum in an incubator with 95% O 2 and 5% CO 2 as described previously [37]. …”

“…Cell viability was evaluated by a nonradioactive CCK-8 kit as described previously [37, 38]. U251-MG and T98 cells (5 × 10 3 ) were cultured in 6-well plates and treated with TMZ alone (25, 50, 100, 200, and 400  μ M), TMZ (25, 50, 100, 200, and 400  μ M) plus FK866 (5 nM and 100 nM), and TMZ plus CHS828 (10 nM and 200 nM).…”

“…Fluorescent TUNEL staining in glioma cells was conducted as described previously [37]. After 24-hour treatment with different drugs, the culture medium was removed.…”

“…Cell necrosis was determined with LDH release using CytoTox-ONE LDH leakage assay as described previously [37]. In brief, the cell culture medium at different time points was transferred to a black fluorescence plate and incubated for 10 minutes with CytoTox-ONE reagent followed by stop solution.…”

“…Four parameters of oxidant stress, including ROS, superoxide anion, total SOD activity, and total antioxidant capacity, were measured using commercial kits from Cell Biolabs Inc. (San Diego, CA) according to the manufacturer's instructions as described previously [6, 37]. …”