Expression Profile of Markers of Apoptosis, Injury and Oxidative Stress in Human Lung Epithelium Cells‑A5449 Receiving Chronic Exposure of Potential Anti‑Tubercular Drug‑trans‑Cyclohexane‑1, 4‑Diamine Derivative‑”9u”

Earlier, we had reported the synthesis of a library of symmetrical trans‑cyclohexane‑1,4‑diamine derivatives and evaluated them for their anti‑mycobacterium activity in the H37RV strain of Mycobacterium tuberculosis. A range of efficacy was recorded in different derivatives and the compound “9u” having an i‑propyl group substitution at the p‑position was found to be the most effective. The compound “9u” was found to be safe for cytotoxic and genotoxic responses in human lung epithelium cells‑A549, even up to many fold higher than that required to kill M. tuberculosis. Hence, compound “9u” was inferred to be a potential anti‑tuberculosis drug of choice. However, the biological safety of compound “9u” upon chronic exposure was still to be answered because anti‑tuberculosis (TB) treatment requires a minimum of 6 months’ exposure of host systems and most of the available anti‑TB drugs are known to induce apoptosis, oxidative stress and injury during such exposures. Thus, the present investigations were aimed to study the alterations, if any, in the expression profile (mRNA and protein) of markers associated with apoptosis, injury and oxidative stress in human lung epithelium cells‑A549 receiving a chronic exposure of the potential anti‑TB compound “9u.” Our findings demonstrate that there was a statistically insignificant transient shift (until 3 weeks) in the markers of apoptosis, injury and oxidative stress, after which expression changes were similar to baseline, when compared with unexposed cells of respective time periods. The studied markers showed linearity in the trend at both mRNA and protein level, indicating the suitability of the test system selected in the study. The data confirm the therapeutic potential of compound “9u” for even long‑term treatment against M. tuberculosis without having any significant apoptosis, injury and oxidative stress.