Downregulation of Glutathione S‑transferase A1 suppressed tumor growth and induced cell apoptosis in A549 cell line

Abstract

Glutathione S-transferase A1 (GSTA1) is a phase II detoxification enzyme and serves a crucial role in anti-cancer drug resistance. In our previous study, GSTA1 was identified to be highly expressed in various subtypes of non-small-cell lung cancer cell lines compared with human embryonic lung fibroblast cell line MRC-5. The aim of the present study was to investigate the effect of GSTA1 expression on the proliferation and apoptosis of A549 cells. GSTA1 expression was knocked down or with overexpressed using lentivirus particles. Western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to assess the protein, and mRNA levels of GSTA1 in A549 cells, respectively. The effect of GSTA1 manipulation on cell proliferation and apoptosis were investigated using MTT assays, Hoechst 33258 staining and flow cytometry, and using A549 cell line xenografts in nude mice. The results of the western blot analysis and RT-qPCR revealed that stable cell models of GSTA1 knockdown, and overexpression were established. The data of the MTT assay indicated that the downregulation of GSTA1 significantly inhibited cell proliferation compared with si-control-transfected cells. These si-GSTA1 A549 cells exhibited typical morphological changes of apoptosis, including chromatin condensation and shrunken nuclei compared with the si-control counterparts. An AnnexinV-fluorescein isothiocyanate assay verified that the downregulation of GSTA1 significantly induced cell apoptosis . In addition, overexpression of GSTA1 significantly promoted tumor growth. Accordingly, downregulation of GSTA1 suppressed tumor growth. In conclusion, GSTA1 plays an important role in regulation of cell proliferation and cell apoptosis in A549 cell line.

Glutathione S-transferase A1 suppresses tumor progression and indicates better prognosis of human primary hepatocellular carcinoma

“…Eight isoforms of cytosolic-soluble GSTs have been recognized in humans, including α, κ, μ, π, σ, θ, ζ, and ω 3,4 . Glutathione S-transferase α1 (GSTA1, Gene ID: 2938) has shown both stimulatory [5][6][7][8] and inhibitory effects [9][10][11][12] on tumorigenesis. The association between genetic polymorphism of GSTA1 and susceptibility to cancer has been discussed in previous studies [13][14][15] , but…”

Glutathione S‑transferase isozyme alpha 1 is predominantly involved in the cisplatin resistance of common types of solid cancer

“…DDP is a first-line anticancer agent that is widely used for the treatment of various types of solid cancer, but frequently confronts with the challenge of DDP-resistance. Inhibition of the expression of a specified GST isozyme by chemicals or siRNA has been found to reverse DDP-resistance in A549/DDP, SCG7901/DDP or SKOV3-/DDP cells, but there are few studies on any of the same GST isozymes potentially involved in DDP-resistance of different types of solid cancer (15,16,(20)(21)(22). The present study indicated that there were some increases in the activities of GSTs and the differently induced expression of tested GST isozymes in SGC7901/DDP, A549/DDP and SKOV3/DDP cells.…”

“…Following 24 h of incubation, DDP was added at a final concentration of 0-80 µmol/l for A549/DDP, 0-40 µmol/l for SKOV3/DDP and 0-20 µmol/l for SGC7901/DDP. Cells were subsequently incubated for 72 h (15,16,(20)(21)(22). CCK-8 was added according to the manufacturer's instructions in order to detect the absorbance at 450 nm using a microplate reader (Bio-Rad Laboratories, Inc.).…”

“…Cells transfected with a positive siRNA against an indicated GST isozyme or negative siRNA (sicontrol) were further treated for 72 h with DDP (10 µmol/l for A549/DDP but 5 µmol/l for SKOV3/DDP and SCG7901/DDP). To examine apoptosis, DDP concentrations were set to maintain >60% survival of the tested solid cancer cells when treated with DDP alone (15,16,(20)(21)(22). Cells after the treatment were collected and washed with pre-cooled PBS prior to staining using Annexin Cy5 apoptosis assay kit (cat.…”

“…Short interfering RNAs (siRNAs) can selectively block the action of a specified protein by inhibiting the expression and/or translation of the target gene. As a result, siRNAs are promising tools for downregulating the expression of GST isozymes in order to detect their roles in drug resistance (15,16) and to identify GST isozymes that may be suitable targets to sensitize common types of drug-resistant solid cancer to cytotoxic agents. Studies on different cancer cells and tissues have identified the contributions of various GST isozymes to the incidence of drug resistance in common types of solid cancer (4,13,14).…”