Abstract
Background: Blood oxidant profile affects tumor cell eradication in cancer patients undergoing thermotherapy.
Objective: The study objectives were the determination of the blood oxidant/antioxidant balance in colorectal cancer (CRC) before and after the XELOX regimen combined with Bevacizumab, and also the effect of treatment on the oxidative stress markers during the first cycle of chemotherapy.
Methods: In this case-control study, 50 healthy controls and 41 colorectal patients were recruited at Popular Hospital Establishment and Avicène Medical Clinic (Maghnia city, Algeria) during 2019. Blood samples were collected from participants before and after treatment. To determine the fluctuations of redox status vis-à-vis of treatment, levels of oxidant and antioxidant parameters were measured using spectrophotometry. Data were analyzed using independent samples t-test and Pearson’s correlation coefficients.
Results: The obtained results highlighted the presence of oxidative stress in CRC cases compared to controls. In CRC, high levels in malondialdehyde (3.06±0.65 µmol/L, p=0.090), superoxide anion (8.38±0.21 µmol /L, p=0.478), carbonyl proteins (0.453±0.11 nmol/mg protein; p=0.292), and peroxynitrite (12.8±4.27 µmol/mL, p=0.093) with significant difference in nitric oxide value (26.07±5.50µmol /L; p=0.0001) were depicted before treatment and, and low total activities of superoxide dismutase (37.81±0.07 U/gHb; p=0.0001) and catalase (29.33±4.99 U/gHb; p=0.0001) with a decrease of glutathione (2.92±0.9 mmol/ L; p=0.0001) concentration were recorded. After treatment, malondialdehyde (1.59±0.11 µmol/L; p=0.003), superoxide anion (7.68±0.17 µmol/L; p=0.003), and carbonyl proteins (0.311±0.02 nmol/mg protein; p=0.024) rates decreased at the opposite of nitric oxide (57.46±9.69 µmol/L; p=0.001) and peroxynitrite (20±3.82 µmol/mL; p=0.002) levels, which increased markedly alike the activities of superoxide dismutase (379.54±0.66 U/gHb; p=0.05) and catalase (131.92±5.83 U/gHb; p=0.0001), and reduced glutathione level (16.11±0.57 mmol/L; p=0.0001) raised significantly.
Conclusion: Limiting the efficiency of drug treatment inhibits the eradicating effect of high blood levels of nitric oxide and peroxynitrite for tumor cells, where cancer patients are nonresponsive to chemotherapeutic treatment. Blood oxidant/antioxidant levels should be an effective guideline for directing the response to cancer treatments, especially the risk of resistance to anti-tumor drugs. Redox homeostasis, which is linked to nutritional profile and lifestyle, should be included in medical check-ups to achieve a better prediction of treatment response.
Keywords: Antioxidants; Oxidative stress; Colorectal cancer; Chemotherapy
