Effect of radiotherapy on activity and concentration of serum paraoxonase-1 in breast cancer patients

Abstract

Paraoxonase-1 (PON1) is an intra-cellular antioxidant enzyme found also in the circulation associated with high-density lipoproteins. The activity of this enzyme has been shown to be decreased in breast cancer (BC) patients. The aims of our study were to investigate the changes produced by radiotherapy (RT) on activity and concentration of serum PON1 in BC patients, and to evaluate the observed variations in relation to clinical and pathological characteristics of patients and tumors, and the response to treatment. We studied 200 women with BC who were scheduled to receive RT following excision of the tumor. Blood for analyses was obtained before and after the irradiation procedure. The control group was composed of 200 healthy women. Relative to control, BC patients had significantly lower serum PON1 activities pre-RT, while PON1 concentrations were at similar levels. RT was associated with a significant increase in serum PON1 activities and concentrations. We observed significant differences in serum PON1 concentrations post-RT between patients with luminal A or luminal B tumors. Serum PON1 concentration post-RT was markedly lower in BC patients with metastases. We conclude that benefit from RT accrues to the BC patients not only through its direct effect on cancer cells but also indirectly by improving the organism’s anti-oxidant defense mechanisms. In addition, our preliminary evidence suggests that the measurement of serum PON1 concentration post-RT could be an efficient prognostic biomarker, and may be used as an index of the efficacy of the RT.

Therapeutic effect of simvastatin on DMBA‐induced breast cancer in mice

“…Although we did not evaluate the mechanism for the increase in PON1 activity in our study, it has been shown that simvastatin can modulate gene expression of this enzyme [50]. Recent studies report a decrease in serum PON1 activity in breast cancer patients [51,52], and it has been suggested that serum PON1 concentration could be an efficient prognostic biomarker for the success of radiotherapy in patients with breast cancer [53]; therefore, it seems that the ability of simvastatin in increasing PON1 activity may help in its therapeutic effect on chemicalinduced breast cancer, as observed in our study.…”

Study of the Radiosensitizing and Radioprotective Efficacy of Bromelain (a Pineapple Extract): In Vitro and In Vivo

“…Measurement of PON1 post-radiotherapy could be an effective clinical biomarker of hepatic and systemic oxidative stress and may be used as an index of the usefulness of radiotherapy. 50 It has been demonstrated to catalyze hydrolysis of lipid hydroperoxides and lactones. 51 PON1 protects serum HDL and LDL particles against lipid peroxidation.…”

Effect of radiotherapy on the expression of cardiovascular disease-related miRNA-146a, -155, -221 and -222 in blood of women with breast cancer

“…They were patients at the Department of Radiation Oncology of Hospital Sant Joan (Reus, Spain). All patients had a Karnofsky Index <70 and were classified as 0 or 1 on the Eastern Cooperative Oncology Group scale [39]. The protocol for metastatic BC patients (2.94%) was to proceed to RT following complete response of the metastases to primary systemic treatment [39].…”