Correlation of Psychological Stress and Induced Nitric Oxide Synthase (iNOS) Expression in Leukemia

Abstract

Early life exposure to adverse conditions such as social life issues, economic problems, health issues, death and separation of loved ones produces stress. Stressful life events (SLEs) disturb the healthy quality of life in multiple ways. The biological response to SLE includes the production and activation of stress hormones. It has been reported that adrenaline, noradrenalin, pituitary, cortisol, prolactin, growth and adrenocorticotropic hormones are responsive to SLE. It is observed that under psychological stress, the circulating level of cortisol and norepinephrine (NE) is higher than in normal subjects. Under stress glucocorticoids (GC), neuroendocrine, norepinephrine and catecholamine produce reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS cause oxidative damage and lower antioxidant capacity and protection. Persistent damaged DNA may lead to the initiation of cancer. It is said that the risk factor of immune dysfunction and cancer may be increased under stress conditions by regulation of iNOS. iNOS is most widely studied as it produces large amounts of nitric oxide which affects many vital processes including apoptosis and angiogenesis in leukemia cells. The regulation of the expression of iNOS is important to control the level of reactive oxygen and nitrogen species that can be lethal to the cell and its environment. It is reported that the microenvironment of a cell affects the expression of iNOS. Therefore, it is concluded that different cells breast, colon, esophagus, bladder, lung, oral cavity and prostate might show different expressions of iNOS. Expression of iNOS is higher in tumor cells than in normal controls. Different studies have been conducted to explore the relationship between iNOS and cancer. The aim of this study is to investigate the expression of iNOS in acute lymphocytic leukemia under stress conditions. The study was performed on ALL blood samples under stress and non-stressed conditions. Polymerase chain reaction (PCR) was performed and gene-specific primers were used to see the iNOS expression. The study showed that expression of iNOS is higher in the patient than in control under stress while non-stressed patients showed significant reduction in iNOS expression. Further research is required to validate the importance of psychological factors and iNOS in cancer.