Reactive oxygen species (ROS) are major contributors to radiation therapy-induced side effects in cancer patients. A fusion antioxidant enzyme comprising glutathione S-transferase (GST), superoxide dismutase 1 (SOD1), and a transmembrane peptide has been shown to effectively mitigate ROS-induced damage. To enhance its targeting capability, the fusion protein was further modified by incorporating a matrix metalloproteinase-2/9 substrate peptide (X) and the transmembrane peptide R9, yielding the antioxidant enzyme GST-SOD1-X-R9 (GS1XR). This modification reduced its transmembrane ability in tumor cells, thereby selectively protecting normal cells from oxidative stress. However, the use of non-human GST poses potential immunogenicity risks. In this study, we employed seamless cloning technology to construct an expression vector containing the human GST gene to replace the non-human GST gene, and then expressed and purified novel fusion antioxidant enzymes GS1R and GS1XR. The protective effects of newly constructed GS1R and GS1XR against hydrogen peroxide (H₂O₂)-induced oxidative damage in L-02 cells were then evaluated using GS1 as a control. Enzymatic activity assays revealed that the specific activity of GST in GS1XR remained unchanged compared to the unmodified protein, while SOD activity was enhanced. Exposure to 200 μmol/L H₂O₂ transiently activated the nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway; however, this activation diminished after 24 h, reducing cell viability to 48.4%. Both GS1R and GS1XR effectively scavenged intracellular ROS, directly counteracting oxidative stress and promoting Nrf2 nuclear translocation, thereby activating antioxidant pathways and restoring cell viability to normal levels. The two enzymes showed comparable efficacy. In contrast, GS1, lacking transmembrane capability, was restricted to scavenging extracellular ROS and provided only limited protection. In conclusion, both novel fusion antioxidant enzymes demonstrated significant potential in safeguarding normal cells from ROS-mediated oxidative damage. The findings provide a foundation for further investigation in related field.
Humans ; Oxidative Stress/drug effects* ; Hydrogen Peroxide ; Antioxidants/metabolism* ; Glutathione Transferase/metabolism* ; Recombinant Fusion Proteins/pharmacology* ; Superoxide Dismutase-1 ; Reactive Oxygen Species/metabolism* ; Superoxide Dismutase/biosynthesis*

Objective To evaluate the relapse rate and the effect of 5-aminolevulinic acid photodynamic therapy(ALA-PDT) combined with fulguration in the treatment of perianal genital warts.Methods 67 patients with perianal genital warts were randomly divided into the three groups.22 cases in the fulguration and ALA-PDT treatment group performed the ALA-PDT treatment immediately after removal of dominant wart by fulguration,once a week,treatment for 3-4 times.22 cases in the ALA-PDT treatment group only underwent ALA-PDT treatment,once a week,treatment for one month.23 cases in the fulguration group were given the traditional fulguration methods one by one electrocautery fulguration gasification treatment for all skin lesions,a weekly batch treatment,treatment for a month.Follow-up six months after the last treatment to determine efficacy and recurrence rate.Results The cure rate of combined treatment group was 90.9％ (20/22),and recurrence rate was 9.1％ (2/22) ;cure rate of photodynamic group was 54.5％ (12/22),and its recurrence rate was 22.7％ (5/22) ; cure rate of fulguration group was 39.1％ (9/23),and the recurrence rate was 43.5％ (10/23).There were statistically significant differences in the cure rate and relapse rate between combination therapy group and electrocautery treatment group (P =0.000,P =0.017).Conclusion The fulguration combined with ALA-PDT in the treatment of perianal genital warts has high cure rate,low recurrence rate,and less side effects.