Neoplastic Pathogenesis Associated with Cigarette Carcinogens

Aging, oxidative stress and degenerative diseases: mechanisms, complications and emerging therapeutic strategies

Aging accompanied by several age-related complications, is a multifaceted inevitable biological progression involving various genetic, environmental, and lifestyle factors. The major factor in this process is oxidative stress, caused by an abundance of reactive oxygen species (ROS) generated in the mitochondria and endoplasmic reticulum (ER). ROS and RNS pose a threat by disrupting signaling mechanisms and causing oxidative damage to cellular components. This oxidative stress affects both the ER and mitochondria, causing proteopathies (abnormal protein aggregation), initiation of unfolded protein response, mitochondrial dysfunction, abnormal cellular senescence, ultimately leading to inflammaging (chronic inflammation associated with aging) and, in rare cases, metastasis. RONS during oxidative stress dysregulate multiple metabolic pathways like NF-κB, MAPK, Nrf-2/Keap-1/ARE and PI3K/Akt which may lead to inappropriate cell death through apoptosis and necrosis. Inflammaging contributes to the development of inflammatory and degenerative diseases such as neurodegenerative diseases, diabetes, cardiovascular disease, chronic kidney disease, and retinopathy. The body's antioxidant systems, sirtuins, autophagy, apoptosis, and biogenesis play a role in maintaining homeostasis, but they have limitations and cannot achieve an ideal state of balance. Certain interventions, such as calorie restriction, intermittent fasting, dietary habits, and regular exercise, have shown beneficial effects in counteracting the aging process. In addition, interventions like senotherapy (targeting senescent cells) and sirtuin-activating compounds (STACs) enhance autophagy and apoptosis for efficient removal of damaged oxidative products and organelles. Further, STACs enhance biogenesis for the regeneration of required organelles to maintain homeostasis. This review article explores the various aspects of oxidative damage, the associated complications, and potential strategies to mitigate these effects.

Shared Lifestyle-Related Risk Factors of Cardiovascular Disease and Cancer: Evidence for Joint Prevention

Cardiovascular disease (CVD) and cancer are leading causes of mortality and morbidity worldwide and are the major focus of the World Health Organization's joint prevention programs. While, diverse diseases, CVD and cancer, have many similarities. These include common lifestyle-related risk factors and shared environmental, metabolic, cellular, inflammatory, and genetic pathways. In this review, we will discuss the shared lifestyle-related and environmental risk factors central to both diseases and how the strategies commonly used to prevent atherosclerotic vascular disease can be applied to cancer prevention.

Lower Prevalence of Human Papillomavirus in Head and Neck Squamous Cell Carcinoma in Middle Eastern Population: Clinical Implications for Diagnosis and Prevention

Introduction Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. The prevalence of human papillomavirus (HPV) in HNSCC varies across regions. Objective This study aimed to determine the prevalence of high-risk HPV (hrHPV) among patients with HNSCC in the Middle East region. Methods Samples from patients with oropharyngeal or laryngeal lesions who underwent biopsy or resection at a tertiary care hospital from 2010 to 2015 were collected. Those confirmed as squamous cell carcinoma (SCC) on histopathology were identified as cases (n = 61), whereas benign lesions were used as controls (n = 83). Immunohistochemistry (IHC) for p16, p53, Ki-67, and in situ hybridization (ISH) for hrHPV genotypes 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 66 were performed on all cases. Results A total of 154 cases were studied: 61 squamous cell cancers (cases), 83 benign lesions (control), and 10 dysplasia specimens. Among the cases, only five (8.6%) were positive for hrHPV, whereas only one control specimen tested positive. The SCC group had higher mean age, male sex, and history of cigarette smoking and alcohol usage. Among the hrHPV-positive SCC cases, 80% had a tumor in the oropharyngeal region. All hrHPV-positive cases were positive for p16 and p53 immunostains. Conclusion Among HNSCC cases, hrHPV was detected at a lower rate compared to other regions of the world. This study suggests that hrHPV plays a minor role in the pathogenesis of HNSCC in this region, compared to tobacco use and alcohol consumption.

Eyelid carcinomas: Tumor aggressiveness tendencies for smokers compared to non‑smokers

During the past few years, several studies have demonstrated that head and neck carcinomas present more aggressive forms for smokers, relative to non-smokers. Our aim was to investigate the tumor aggressiveness for patients with eyelid carcinomas, in relation to tobacco consumption, as well as other demographic and clinical data. For 98 patients with eyelid carcinomas, we studied the relationship between the duration of their symptoms and their tumor stage at first diagnosis, trying to determine potential correlations with smoking status and several other clinical parameters. Our data revealed that, for the same duration of symptoms, tobacco consumers tended to have higher tumor stages, which did not correlate with other variables. For early diagnosed tumors, within the first year of symptoms, smokers presented 6.044 times higher odds to exhibit more advanced tumor stages, compared to non-smokers, and this value decreased to 4.501, up to 5 years of the presence of symptoms (P<0.05). We also noted that, for smokers, an increased age was associated with increased tumor stages, which was opposed to non-smokers, regardless of their symptom duration [average odds ratio (OR) 1.122, P<0.05]. Tumor aggressiveness was therefore associated with tobacco consumption, leading to an increased risk of developing more aggressive forms of eyelid carcinomas for smokers, compared to non-smokers.

Thioredoxin as a novel sensitive marker of biological stress response in smoking

Thioredoxin is a low molecular weight (approximately 12 kDa) redox protein, and protects against harmful stimuli such as oxidative stress. Smoking evokes oxidative stress, among other biological responses. The clinical relevance of thioredoxin in smoking has not been fully investigated. Here, we examined the effects of smoking on serum and urinary thioredoxin levels, in comparison with various stress markers. Serum thioredoxin levels in the smoking group (10 subjects) were significantly higher than those of the non-smoking group (5 subjects). After smoking, serum thioredoxin levels significantly decreased, while urinary levels significantly increased. On the other hand, the levels of serum and salivary cortisol, plasma norepinephrine, salivary amylase, salivary thioredoxin, and urinary 8-hydroxy-2'-deoxyguanosine levels before and after smoking were not significantly different. These results suggest that a decrease in thioredoxin in the serum and the concomitant increase in the urine is a novel sensitive marker of biological stress responses induced by smoking. The change seems to be evoked by mechanisms different from hormonal or 8-hydroxy-2'-deoxyguanosine-forming stress responses.

Protective Effects of Pinus halepensis Bark Extract and Nicotine on Cigarette Smoke-induced Oxidative Stress in Keratinocytes

BACKGROUND/AIM

Cigarette smoke (CS) is a major environmental health threat. The oxidative stress induced by CS on keratinocytes and the possible protective effect of nicotine, its receptor inhibitors, and Pinus halepensis bark extract in relation to known antioxidants were investigated.

MATERIALS AND METHODS

Primary mouse keratinocytes were exposed to cigarette smoke in the presence and absence of Pinus halepensis bark extract (1 μg/ml), rutin (50 μM) and ascorbic acid (250 μM), nicotine (1 μM) with or without mecamylamine (5 μM) and α-bungarotoxin (0.1 μM). Keratinocyte viability and oxidative stress were evaluated by MTT and fluorescence assays.

RESULTS

Pinus halepensis bark extract decreased the oxidative stress and increased the viability of keratinocytes, and moreover, these effects were more pronounced compared to the mixture of rutin and L-ascorbic acid. Nicotine significantly enhanced the viability potentiation of the beneficial effect induced by Pinus halepensis bark extract. Mecamylamine and α-bungarotoxin showed no specific effect.

CONCLUSION

Pinus halepensis bark extract in combination with nicotine may successfully reverse skin damage induced by cigarette smoke.