Environmental and occupational determinants of lung cancer

Analysis of urinary metabolites of polycyclic aromatic hydrocarbons in precarious workers of highly exposed occupational scenarios in Mexico

Exposure to polycyclic aromatic hydrocarbons (PAHs) is a risk factor for human health. Workers are a vulnerable group due to their high exposure and therefore require special attention to mitigation measurements; however, some groups of workers are especially vulnerable, precarious workers. The objective of this research was to evaluate mixtures of hydroxylated PAHs (OH-PAHs) in precarious workers in Mexico. The following activities were evaluated: (i) brickmakers (TER), stonemasons (ESC), indigenous workers (TOC) and mercury miners (CAM). Ten OH-PAHS were analyzed: 1-hydroxynaphtalene and 2-hydroxynaphtalene; 2-,3- and 9-hydroxyfluorene; 1-,2-,3- and 4-hydroxyphenanthrene; and 1-hydroxypyrene in urine by GC-MS, chemical fingerprints of the sites were established by multivariate analysis. One hundred forty-nine precarious workers participated in the study. The populations presented total OH-PAHs concentrations of 9.20 (6.65-97.57), 14.8 (9.32-18.85), 15.7 (6.92-195.0), and 101.2 (8.02-134.4) μg/L for CAM, ESC, TER, and TOC, respectively (median (IQR)). The results of the multivariate analysis indicate that the indigenous population presented a different fingerprint compared to the three scenarios. The chemical fingerprints among the brickmakers and mercury mining population were similar. The results of the concentrations were similar and in some metabolites higher than workers in occupations classified as carcinogenic by the IARC; therefore, the control of exposure in these occupations acquires great importance and surveillance through biological monitoring of OH-PAHs should be applied to better estimate exposure in these working populations.

Mutational landscape of multiple primary lung cancers and its correlation with non-intrinsic risk factors

Multiple primary lung cancers (MPLCs) harbour various genetic profiles among the tumours, even from individuals with same non-intrinsic risk factors. Paired mutational analyses were performed to obtain a census of mutational events in MPLC and assess their relationship with non-intrinsic risk factors. Thirty-eight surgical specimens from 17 patients diagnosed as MPLC were used. Extracted DNAs were sequenced for somatic mutations in 409 cancer-associated genes from a comprehensive cancer panel. We statistically analysed the correlation between each driver mutation frequency and non-intrinsic risk factors using Fisher's exact test, and whether genetic mutations occurred concomitantly or randomly in MPLC using an exact test. Comprehensive genetic analyses suggested different mutation profiles in tumours within the same individuals, with some exceptions. EGFR, KRAS, TP53, or PARP1 mutations were concomitantly detected in some MPLC cases. EGFR mutations were significantly more frequent in never or light smokers and females. Concomitant EGFR or KRAS mutations in MPLCs were significantly more frequent than expected by chance (P = .0023 and .0049, respectively) suggesting a more prominent role of non-intrinsic risk factors in EGFR and KRAS mutations than other mutations, which occurred more randomly. Concomitant EGFR or KRAS mutations were particularly prominent in never or light smokers and males.

Crude oil and public health issues in Niger Delta, Nigeria: Much ado about the inevitable

The importance of crude oil has come at a great cost. In many developing economies of the world, it can be described as the bitter-sweet crude for its double-edged impacts on the welfare, wellness and wellness of the people. Agitations and restiveness remain characteristic features of Niger Delta following claims of exploitation and neglect of the local population by the multinationals. Literature on the environmental and public health impacts of crude oil was searched from relevant databases such as google scholar, Science Direct, Scopus and PubMed. This paper is a translational scientific and toxicological insight on what should be done by the major players rather than casting unending aspersions. Since living near oil spills and crude oil production sites is an environmental stressor occasioned by exposure to both chemical pollutants and physical menace that are all detrimental to health, cumulative risk assessment CRA is proposed as a viable approach for a comprehensive understanding of the size of this problem. Multinational oil companies should support development of Environmental Medicine Research which will in turn generate data on both how to harness the natural resources to combat the public health issues associated with oil exploration and the mitigation and remediation of the environment. This endeavor will create a waste-to-wealth program that will pacify the restiveness in oil exploring communities. It will be interesting to know that in the same environment that breeds the elephant-in-the-parlor lies the natural antidotes to check-mate the public health malady.

Females and Males Show Differences in Early-Stage Transcriptomic Biomarkers of Lung Adenocarcinoma and Lung Squamous Cell Carcinoma

The incidence and mortality rates of lung cancers are different between females and males. Therefore, sex information should be an important part of how to train and optimize a diagnostic model. However, most of the existing studies do not fully utilize this information. This study carried out a comparative investigation between sex-specific models and sex-independent models. Three feature selection algorithms and five classifiers were utilized to evaluate the contribution of the sex information to the detection of early-stage lung cancers. Both lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) showed that the sex-specific models outperformed the sex-independent detection of early-stage lung cancers. The Venn plots suggested that females and males shared only a few transcriptomic biomarkers of early-stage lung cancers. Our experimental data suggested that sex information should be included in optimizing disease diagnosis models.

Environmental Awareness for Patients with COPD Undergoing Pulmonary Rehabilitation: Is It of Added Value?

Chronic obstructive pulmonary disease (COPD) is impacted by exposure to environmental contaminants. Improving health literacy on this topic might help to optimize health outcomes. We aimed to design and deliver a health-education session about the impact of environmental contaminants on respiratory symptoms and explore participants' perceptions on such session. Patients with COPD were recruited from a pulmonary rehabilitation (PR) program. Two focus groups were first conducted to explore knowledge amongst the group. Then, the session was designed and delivered, and three focus groups were conducted to obtain feedback from participants. Data were analyzed thematically by two independent researchers. Thirty-one patients (71 ± 8 years old, FEV1 = 47.6 ± 16.8% predicted; 74.2% male) were included. Prior to the session, participants recognized the importance of this topic and described avoidance strategies to deal with symptom triggering due to air pollution. After the session, participants had their knowledge validated, kept some avoidance strategies, but also adapted some "unavoidable" activities of daily living. Patients with COPD value education on this topic, and PR offers a friendly environment to discuss prevention and management strategies. Contents of the session are provided to help deliver these sessions. Future studies could investigate the effectiveness of this intervention on self-management and exacerbations of COPD.

The Inducible Role of Ambient Particulate Matter in Cancer Progression via Oxidative Stress-Mediated Reactive Oxygen Species Pathways: A Recent Perception

Simple Summary

Particulate matter, especially the fine fraction PM2.5, is officially stated as carcinogenic to human. There are compelling evidences on the association between PM2.5 exposure and lung cancer, and there are also some preliminary data reporting the significant links between this fraction with non-lung cancers. The underlying mechanisms remain unclear. Further studies related to such scope are highly required. The purpose of this work is to systemically analyze recent findings concerning the relationship between PM2.5 and cancer, and to thoroughly present the oxidative stress pathways mediated by reactive oxygen species as the key mechanism for carcinogenesis induced by PM2.5. This will provide a more comprehensive and updated knowledge regarding carcinogenic capacity of PM2.5 to both clinicians and public health workers, contributing to preventive and therapeutic strategies to fight against cancer in human.

Abstract

Cancer is one of the leading causes of premature death and overall death in the world. On the other hand, fine particulate matter, which is less than 2.5 microns in aerodynamic diameter, is a global health problem due to its small diameter but high toxicity. Accumulating evidence has demonstrated the positive associations between this pollutant with both lung and non-lung cancer processes. However, the underlying mechanisms are yet to be elucidated. The present review summarizes and analyzes the most recent findings on the relationship between fine particulate matter and various types of cancer along with the oxidative stress mechanisms as its possible carcinogenic mechanisms. Also, promising antioxidant therapies against cancer induced by this poison factor are discussed.

Clothianidin induces DNA damage and oxidative stress in bronchial epithelial cells

Clothianidin (CHN) is a member of the neonicotinoid group of insecticides. Its oxidative and DNA damage potential for human lung cells are not known. Therefore, the present study was designed to examine the effects of CHN on DNA damage and oxidative stress in human bronchial epithelial cells (BEAS-2B) treated with CHN for 24, 72, and 120 hr. Our results indicate that CHN decreased cell viability in a concentration-dependent manner. CHN induced DNA single-strand breaks because alkaline comet parameters such as tail intensity, DNA in the tail, tail moment, and tail length increased. All CHN concentrations also significantly induced the formation of DNA double-strand breaks (DSBs) because it increased phosphorylated H2AX protein foci for all treatment times and p53-binding protein 1 foci for all treatments except for the lowest concentration (0.15 mM) of 120-hr treatment. DNA damage caused by DNA DSBs was not repaired in a 24-hr recovery period. CHN also induced oxidative stress by decreasing reduced glutathione and increasing lipid peroxidation. These results make it necessary to conduct studies about the detailed carcinogenic potential of CHN in humans because it can induce both oxidative and DNA damage.

EGFR mutation status in a series of Turkish non-small cell lung cancer patients

Epidermal growth factor receptor (EGFR) mutations are potential markers driving carcinogenesis, and may alter the response to EGFR tyrosine kinase inhibitors in patients with non-small cell lung cancer (NSCLC). The frequency of EGFR mutations in patients with NSCLC differs according to sex, smoking habits and regional-based ethnicity differences. The aim of the present study was to determine the frequency of EGFR mutations in Turkish patients with NSCLC to highlight the importance of regional differences, and their associations with patient characteristics. Genomic DNA was extracted from formalin-fixed and paraffin-embedded tumor tissue sections of 409 NSCLC patients. The most common EGFR mutations in exons 18, 19, 20 and 21 were detected using BioFilmChip-based microarray assay. The overall EGFR mutation frequency was 16.6%, and the highest mutation frequencies were observed in exon 19 (6.4%) and exon 21 (7.3%). There was a higher frequency of EGFR mutations in females compared with males and in never-smokers compared with smokers (both P≤0.05). These results were similar to other European population-based studies, but not consistent Middle-Eastern based studies. The present study may contribute to understanding the gradient frequency of EGFR mutation across different ethnicities, and in designing genome wide-based collaborations that may reveal novel decision making and susceptibility mutations in EGFR in patients with NSCLC.

Plantamajoside modulates the proliferation, stemness, and apoptosis of lung carcinoma via restraining p38MAPK and AKT phosphorylation

BACKGROUND

Plantamajoside (PMS), an active anti-inflammatory component and antioxidant derived from Herba Plantaginis, has been reported to exert a suppressive effect in liver cancer in vivo. In this study, we tested the effects of PMS on the metastatic 95D cell line.

METHODS

95D cells were characterized as most sensitive to PMS across several lung cancer cell lines. Cell viability within 24 h was tested with CCK-8. Different concentrations of PMS (0, 50, 100, and 200 µg/mL) and 5 µg/mL of cisplatin were established for later 24 h treatment. Relative mRNA and protein expression were assessed with PCR and Western blotting. Cell proliferation and stemness were indicated with colony and sphere formation. Cell metastasis was evaluated with wound healing and Transwell. Apoptotic cells and mitochondrial membrane potential were investigated with flow cytometry.

RESULTS

CCK-8 assay showed PMS to inhibit the viability of 95D cells in a dose-dependent manner. PMS decreased colony formation and inhibited stemness in 95D cells. Invasion and migration were also inhibited. Moreover, PMS induced cell apoptosis, and decreased mitochondrial membrane potential. All of these effects were dose dependent. Interestingly, PMS treatment reduced the protein expression of p-p38 MAPK and p-AKT but not that of p38 MAPK and AKT.

CONCLUSIONS

PMS inhibited proliferation, stemness, and migration, and initiated apoptosis in 95D cells, possibly through p38 MAPK and AKT dephosphorylation and mitochondria dysfunction. These findings support the promise of PMS as a prodrug in lung cancer treatment.

Sex-specific risks and trends in lung cancer mortality across occupations and economic activities in Switzerland (1990-2014)

OBJECTIVES

To assess lung cancer mortality across occupations and economic activities/industries in Switzerland using three statistical estimates.

METHODS

All Swiss residents aged 18-65 during the 1990 or 2000 censuses were followed through 2014 to ascertain information on date and cause of death. For every occupation and economic activity/industry, causal mortality ratios (CMR) and standardised mortality ratios (SMR) were computed using national cause-specific mortality rates. We also calculated relative SMR (rSMR) and conducted analyses stratified by socioeconomic variables, job skill level and calendar periods.

RESULTS

The study sample comprised 5 834 618 participants (111 162 348 person-years). SMR and CMR led to similar results, while rSMR were generally higher. We found 18 occupations in men, 10 occupations in women and 3 industries in each sex with an excess of lung cancer mortality. Among men, rubber and plastic products machine operators, and workers in mining and quarrying, and construction industries were at high risk. Among women, motor vehicle drivers and workers in trade, repair of motor vehicles and of domestic articles and manufacture of goods industries showed the highest risks. In both sexes, hotel and restaurant workers presented an excess of lung cancer mortality.

CONCLUSION

Most of the activities and occupations in which we observed excess lung cancer mortality have previously been observed to involve occupational exposure to lung carcinogens. These findings suggest that the number of occupational lung cancer is likely underestimated by the official Swiss statistics. Further research should address this question and the exposure-effect relationships in the most at-risk occupational groups.

The anti-tumor effect of taxifolin on lung cancer via suppressing stemness and epithelial-mesenchymal transition in vitro and oncogenesis in nude mice

Background

Taxifolin is a natural flavonoid with anti-oxidant and anti-proliferative properties. In this study, we investigated the stemness-related inhibitory effects of taxifolin in two lung cancer cell lines, A549 and H1975, as well as in A549 xenografts.

Methods

A549 and H1975 cells, as well as A549 xenograft BALB/c mice were treated with taxifolin. Cell viability, stemness, mobility and protein expression were tested with Cell counting kit-8 (CCK-8), Colony formation assay, Flow cytometry, Transwell, Western blot and Immunohistochemistry, respectively.

Results

CCK-8 exhibited an obvious toxicity of taxifolin to both cell lines at higher dose. Then taxifolin of 0, 25, 50, and 100 µM/L were subsequently used. Taxifolin exhibited inhibitory effects on stemness and sphere formation, reduced protein expression of SOX2 and OCT4, and reduced CD133-positive cells. Furthermore, taxifolin decreased invasive cells, reduced N-cadherin and vimentin while increased E-cadherin expression, indicating that epithelial-mesenchymal transition (EMT) was inhibited. All of the effects observed were exhibited in a dose-dependent manner, and A549 cells proved to be more sensitive to taxifolin than H1975 cells. Taxifolin inactivated PI3K and TCF4 protein phosphorylation; however, taxifolin was not observed to have an effect on NF-κB P65 or STAT3. Taxifolin also suppressed tumor growth in A549 xenograft BALB/c mice, with decreased SOX2 and OCT4 expression and inhibited PI3K and TCF4.

Conclusions

In summary, taxifolin inhibited stemness and EMT in lung cancer cells possibly via the inactivation of PI3K and OCT4. Taxifolin could be a potential prodrug or serve as an adjuvant in lung cancer treatment.

Lung cancer in never smokers: The role of different risk factors other than tobacco smoking

Lung cancer (LC), the leading cause of cancer-related deaths worldwide, is a complex and highly heterogeneous disease. Additional to its biological complexity, LC patients are often confronted with a high degree of stigma, mostly from the association of the disease with tobacco. Nonetheless, a proportion of LC patients are never-smokers, a population which we are beginning to comprehensively explore. Several risk factors have been linked to LC in never-smokers. Studies have consistently shown that radon exposure and domestic fuel smoke increase LC risk. Additionally, infections such as Mycobacterium tuberculosis, and Human Papilloma Virus are also risk factors. Other less conclusive associations include inflammatory diseases such as asthma and sarcoidosis. Moreover, we are now aware that molecular characteristics of LC vary widely according to smoking history, with important therapeutic implications. This review comprehensively assesses the current knowledge in terms of risk factors and disease characteristics in the never-smoker lung cancer population.

Role of Rad51 and DNA repair in cancer: A molecular perspective

The maintenance of genome integrity is essential for any organism survival and for the inheritance of traits to offspring. To the purpose, cells have developed a complex DNA repair system to defend the genetic information against both endogenous and exogenous sources of damage. Accordingly, multiple repair pathways can be aroused from the diverse forms of DNA lesions, which can be effective per se or via crosstalk with others to complete the whole DNA repair process. Deficiencies in DNA healing resulting in faulty repair and/or prolonged DNA damage can lead to genes mutations, chromosome rearrangements, genomic instability, and finally carcinogenesis and/or cancer progression. Although it might seem paradoxical, at the same time such defects in DNA repair pathways may have therapeutic implications for potential clinical practice. Here we provide an overview of the main DNA repair pathways, with special focus on the role played by homologous repair and the RAD51 recombinase protein in the cellular DNA damage response. We next discuss the recombinase structure and function per se and in combination with all its principal mediators and regulators. Finally, we conclude with an analysis of the manifold roles that RAD51 plays in carcinogenesis, cancer progression and anticancer drug resistance, and conclude this work with a survey of the most promising therapeutic strategies aimed at targeting RAD51 in experimental oncology.