Fine particulate matter (PM2.5) promotes chemoresistance and aggressive phenotype of A549 lung cancer cells.

Lung cancer is one of the most aggressive malignancies with a high mortality rate. In large cities, particulate matter (PM) is a common air pollutant. High PM levels with aerodynamic size ≤2.5 µm (PM2.5) associates with lung cancer incidence and mortality. In this work, we explored PM2.5 effects on the behavior of lung cancer cells. To this, we chronically exposed A549 cells to increasing PM2.5 concentrations collected in México City, then evaluating cell proliferation, chemoresponse, migration, invasion, spheroid formation, and P-glycoprotein and N-cadherin expression. Chronic PM2.5 exposure from 1 µg/cm2 stimulated A549 cell proliferation, migration, and chemoresistance and upregulated P-glycoprotein and N-cadherin expression. PM2.5 also induced larger multicellular tumor spheroids (MCTS) and less disintegration compared with control cells. Therefore, these results indicate lung cancer patients exposed to airborne PM2.5 as urban pollutant could develop more aggressive tumor phenotypes, with increased cell proliferation, migration, and chemoresistance.

Air Pollution and Lung Cancer: Contributions of Extracellular Vesicles as Pathogenic Mechanisms and Clinical Utility.

PURPOSE OF REVIEW: This review addresses the pressing issue of air pollution's threat to human health, focusing on its connection to non-small cell lung cancer (NSCLC) development. The aim is to explore the role of extracellular vesicles (EVs) as potential pathogenic mechanisms in lung cancer, including NSCLC, induced by air pollutants. RECENT FINDINGS: Recent research highlights EVs as vital mediators of intercellular communication and key contributors to cancer progression. Notably, this review emphasizes the cargo of EVs released by both cancerous and non-cancerous lung cells, shedding light on their potential role in promoting various aspects of tumor development. The review underscores the importance of comprehending the intricate interplay between air pollution, biological damage mechanisms, and EV-mediated communication during NSCLC development. Major takeaways emphasize the significance of this understanding in addressing air pollution-related lung cancer. Future research avenues are also highlighted, aiming to enhance the applicability of EVs for diagnosis and targeted therapies, ultimately mitigating the inevitable impact of air pollution on NSCLC development and treatment.

In vitro toxicity and lung cancer risk: Atmospheric particulate matter from a city in southeastern Brazil impacted by biomass burning.

The effects of PM10 on human health were investigated using samples collected in São Carlos city (São Paulo state), by the determination of the concentrations of PAHs and derivatives, together with evaluations of cytotoxicity and the formation of ROS in in vitro tests. In 2016, the mean concentrations of PM10, ΣPAHs, Σoxy-PAHs, Σnitro-PAHs, Σsaccharides, and Σions were 21.12 ± 9.90 µg m-3, 1.47 ± 1.70 ng m-3, 0.37 ± 0.31 ng m-3, 0.84 ng m-3, 119.91 ± 62.14 ng m-3, and 5.66 ± 4.52 µg m-3, respectively. The PM10 concentrations did not exceed the limit thresholds set by national legislation, however, the annual lung cancer risk calculated was 2.59 ± 1.22 cases per 100,000 people, in the dry season, which accounts for the annual risk (April to September). Moreover, the carcinogenic activities of the PAHs mixture were more than 1000-fold higher in the dry season (dry season: BaPeq = 0.30 ng m-3; wet season BaPeq = 0.02 ng m-3). The concentrations of most analytes were also higher during the dry season, as had already been demonstrated in the same city. This was due to reductions in precipitation, relative humidity and air temperature, and increased biomass burning, which was the main source of PM10 in the city in 2016 (contribution rate of more than 50%). Toxicological results also showed the negative impacts of PM10, exposure to PM10 extracts for 72 h reduced the viability of A549 and MRC5 cells, and the formation of ROS was observed. The cellular responses obtained using combined and individual extracts of PM10 differed and were sometimes associated with specific compounds. These demonstrate the importance of monitoring PM toxicity using different approaches and the main anthropogenic sources' contribution. Therefore, to improve air quality and human health, existing legislation needs to be modified to incorporate these tests.

Mesothelioma in a developing country: a retrospective analysis of the diagnostic process.

OBJECTIVE: To evaluate the process of diagnosing patients with malignant pleural mesothelioma (MPM) at a tertiary care hospital. METHODS: This was a retrospective study involving patients referred to a tertiary-care cancer center in Brazil between 2009 and 2020. The diagnostic process was divided into four steps: onset of symptoms, referral to a specialist visit, histopathological diagnosis, and beginning of treatment. The intervals between each phase and the factors for delays were evaluated. Data including clinical status, radiological examinations, staging, treatment modalities, and survival outcomes were collected. RESULTS: During the study period, 66 patients (mean age = 64 years) were diagnosed with MPM and underwent treatment. Only 27 (41%) of the patients had knowledge of prior exposure to asbestos. The median number of months (IQR) between the onset of symptoms and the first specialist visit, between the specialist visit and histopathological characterization, and between definite diagnosis and beginning of treatment was, respectively, 6.5 (2.0-11.4), 1.5 (0.6-2.1), and 1.7 (1.2-3.4). The knowledge of prior asbestos exposure was associated with a shorter time to referral to a specialist (median: 214 vs. 120 days; p = 0.04). A substantial number of nondiagnostic procedures and false-negative biopsy results (the majority of which involved the use of Cope needle biopsy) were found to be decisive factors for the length of waiting time. The mean overall survival was 11.9 months. CONCLUSIONS: The unfamiliarity of health professionals with MPM and the patient's lack of knowledge of prior asbestos exposure were the major factors to cause a long time interval between the onset of symptoms and beginning of treatment. An overall survival shorter than 1 year is likely to have been due to the aforementioned delays.

The Endocrine Disruptor Compound Bisphenol-A (BPA) Regulates the Intra-Tumoral Immune Microenvironment and Increases Lung Metastasis in an Experimental Model of Breast Cancer.

Breast cancer (BC) metastasis represents the main physiopathology leading to poor prognosis and death. Bisphenol A (BPA) is a pollutant, classified as an endocrine-disrupting chemical compound with estrogenic properties, their exposure in the early stages of neonatal life leads to an increase in the size and weight of breast tumors and induces cellular changes in the tumoral immune microenvironment where cytokines play a key role. Thus, we used female BALB/c mice exposed neonatally to a single dose of BPA. Once mice reached sexual maturity, a mammary tumor was induced, injecting 4T1 cells in situ. After 25 days of injection, we evaluated endocrine alterations, cytokine expression, tissue alterations denoted by macro or micro-metastasis in the lung, and cell infiltration induced by metastasis. We found that BPA neonatal treatment did not show significant endocrine alterations. Noteworthy, BPA led to an augmented rate of metastasis to the lung associated with higher intratumoral expression of IL-1ß, IL-6, IFN-γ, TNF-α, and VEGF. Our data suggest that cytokines are key players in the induction of BC metastasis and that BPA (an environmental pollutant) should be considered as a risk factor in the clinical history of patients as a possible inductor of BC metastasis.

Severe oral ulcerative and lichenoid lesions associated with adrenal insufficiency in a patient treated with nivolumab: Report of a case and review of literature.

Nivolumab, an antibody against anti-programmed death type 1, has been used for treatment of advanced non-small cell lung cancer with improvement of overall survival. Usually, diarrhea, cutaneous rash, and pruritus are reported as the most common immune-related adverse effects of nivolumab therapy. Oral lesions and secondary adrenal insufficiency sometimes occur but usually are rare events. We report a case of a patient treated with nivolumab who then showed persistent oral ulcerative and lichenoid lesions, which were refractory to topical corticosteroids. The oral lesions were concomitant to nivolumab-induced adrenal insufficiency. These adverse events led to nivolumab discontinuation, which favored oral lesion healing and adrenal insufficiency remission. Through a brief review of the literature concerning nivolumab toxicity in the oral cavity, we discuss the clinical aspect and management of these lesions.

Particulate Matter (PM10) Promotes Cell Invasion through Epithelial-Mesenchymal Transition (EMT) by TGF-ß Activation in A549 Lung Cells.

Air pollution presents a major environmental problem, inducing harmful effects on human health. Particulate matter of 10 µm or less in diameter (PM10) is considered an important risk factor in lung carcinogenesis. Epithelial-mesenchymal transition (EMT) is a regulatory program capable of inducing invasion and metastasis in cancer. In this study, we demonstrated that PM10 treatment induced phosphorylation of SMAD2/3 and upregulation of SMAD4. We also reported that PM10 increased the expression and protein levels of TGFB1 (TGF-ß), as well as EMT markers SNAI1 (Snail), SNAI2 (Slug), ZEB1 (ZEB1), CDH2 (N-cadherin), ACTA2 (α-SMA), and VIM (vimentin) in the lung A549 cell line. Cell exposed to PM10 also showed a decrease in the expression of CDH1 (E-cadherin). We also demonstrated that expression levels of these EMT markers were reduced when cells are transfected with small interfering RNAs (siRNAs) against TGFB1. Interestingly, phosphorylation of SMAD2/3 and upregulation of SMAD induced by PM10 were not affected by transfection of TGFB1 siRNAs. Finally, cells treated with PM10 exhibited an increase in the capacity of invasiveness because of EMT induction. Our results provide new evidence regarding the effect of PM10 in EMT and the acquisition of an invasive phenotype, a hallmark necessary for lung cancer progression.

Association between the polymorphism of three genes involved in the methylation and efflux of arsenic (As3MT, MRP1, and P-gp) with lung cancer in a Mexican cohort.

Lung cancer is the most common neoplasm and the primary cause-related mortality in developed and in most of nondeveloped countries. Epidemiological studies have demonstrated that even at low arsenic doses, the lungs are one of the main target organs and that chronic arsenic exposure has been associated with an increase in lung cancer development. Among the risk factors for cancer, arsenic methylation efficiency (As3MT) and the clearance of arsenic from cells by two members of the ATP-binding cassette (ABC) transporter family (multidrug resistance protein 1 [MRP1] and P-glycoprotein [P-gp]) play an important role in processing of arsenic and decreasing its intracellular levels. This study aimed to evaluate the association between chronic exposure to arsenic with polymorphism of three proteins involved in arsenic metabolism and efflux of the metalloid in subjects with lung cancer. Polymorphism in As3MT, MRP1, and P-gp modified the arsenic metabolism increasing significantly the AsV urinary levels. A significant association between MRP1 polymorphisms with an increase in the risk for cancer was found. The high inorganic arsenic urinary levels registered in the studied subjects suggest a reduction in the efficiency of As3MT, MRP1, and P-gp firstly because of gene polymorphisms and secondarily because of high internal inorganic arsenic levels. MRP1 polymorphism was associated with a twofold increase in the risk of lung cancer.

Lung cancer related to occupational exposure: an integrative review.

OBJECTIVE: To identify in the literature the carcinogenic agents found in the work environment, the occupations and the risk for lung cancer. METHOD: A descriptive and analytical study of the Integrative Literature Review type was carried out in national and international databases from the last ten years in the period from 2009 to 2018, concerning 32 studies referring to association between carcinogenic substances to which the worker is exposed and lung cancer. RESULTS: Nine (28.1%) publications originated in China and only one in Brazil. The most exposed workers were from the secondary sector, 50% being from industry and 6.2% from construction, mostly male. Asbestos and silica stood out among the carcinogenic substances most associated with lung cancer risk, accounting for 37.5% and 28.1%, respectively. CONCLUSIONS: The association between occupational exposure and the risk for lung cancer was characterized in this research by the substantial scientific evidence from the described studies that confirm this association.

Lung cancer related to occupational exposure: an integrative review / Cáncer de pulmón relacionado con la exposición ocupacional: revisión integrativa / Câncer de pulmão relacionado à exposição ocupacional: revisão integrativa

ABSTRACT Objective: To identify in the literature the carcinogenic agents found in the work environment, the occupations and the risk for lung cancer. Method: A descriptive and analytical study of the Integrative Literature Review type was carried out in national and international databases from the last ten years in the period from 2009 to 2018, concerning 32 studies referring to association between carcinogenic substances to which the worker is exposed and lung cancer. Results: Nine (28.1%) publications originated in China and only one in Brazil. The most exposed workers were from the secondary sector, 50% being from industry and 6.2% from construction, mostly male. Asbestos and silica stood out among the carcinogenic substances most associated with lung cancer risk, accounting for 37.5% and 28.1%, respectively. Conclusions: The association between occupational exposure and the risk for lung cancer was characterized in this research by the substantial scientific evidence from the described studies that confirm this association.

RESUMEN Objetivo: Identificar en la literatura los agentes cancerígenos presentes en el entorno laboral, las ocupaciones y el riesgo de cáncer de pulmón. Método: Estudio descriptivo y analítico de una revisión integradora realizada en una base de datos nacional e internacional de los últimos diez años, entre 2009 y 2018, que comprende 32 estudios referidos a la vinculación entre el cáncer de pulmón y las sustancias cancerígenas de exposición ocupacional. Resultados: Nueve (28,1%) publicaciones tuvieron su origen en China y solo una en Brasil. Los trabajadores más expuestos pertenecían al sector secundario, el 50% a la industria y un 6,2% a la construcción, siendo en su mayoría hombres. El asbesto y la sílice se destacaron entre las sustancias cancerígenas más asociadas con el riesgo de cáncer de pulmón, con índices de 37,5% y el 28,1%, respectivamente. Conclusiones: La vinculación entre la exposición ocupacional y el riesgo de cáncer de pulmón se caracterizó en esta investigación por la evidencia científica sustancial de los estudios descriptos que confirman esta asociación.

RESUMO Objetivo: Identificar na literatura os agentes carcinogênicos presentes no ambiente ocupacional, as ocupações e o risco do câncer de pulmão. Método: Estudo descritivo e analítico de revisão integrativa realizada em base de dados nacionais e internacionais dos últimos dez anos, entre 2009 e 2018, compreendendo 32 estudos referentes à associação entre câncer de pulmão e substâncias carcinogênicas de exposição ocupacional. Resultados: Nove (28,1%) publicações originadas na China e apenas uma brasileira. Os trabalhadores mais expostos foram do setor secundário, sendo 50% da indústria e 6,2% da construção civil, em sua maioria do sexo masculino. O amianto e a sílica sobressaíram-se entre as substâncias carcinogênicas mais associadas ao risco de câncer de pulmão correspondendo a 37,5% e 28,1%, respectivamente. Conclusões: A associação entre a exposição ocupacional e o risco de câncer de pulmão ficou caracterizada nesta pesquisa pelas substanciais evidências científicas dos estudos descritos que confirmam essa associação.

Lung Cancer Mortality Trends in a Brazilian City with a Long History of Asbestos Consumption.

There are scarce epidemiological studies on lung cancer mortality in areas exposed to asbestos in developing countries. We compared the rates and trends in mortality from lung cancer between 1980 and 2016 in a municipality that made extensive use of asbestos, Osasco, with rates from a referent municipality with lower asbestos exposure and with the rates for the State of São Paulo. We retrieved death records for cases of lung cancer (ICD-9 C162) (ICD-10 C33 C34) from 1980 to 2016 in adults aged 60 years and older. The join point regression and age-period-cohort models were fitted to the data. Among men, there was an increasing trend in lung cancer mortality in Osasco of 0.7% (CI: 0.1; 1.3) in contrast to a mean annual decrease for Sorocaba of -1.5% (CI: -2.4; -0.6) and a stable average trend for São Paulo of -0.1 (IC: -0.3; 0.1). Similar increasing trends were seen in women. The age-period-cohort model showed an increase in the risk of death from 1996 in Osasco and a reduction for Sorocaba and São Paulo State during the same period. Our results point to a need for a special monitoring regarding lung cancer incidence and mortality in areas with higher asbestos exposure.

High frequency and severity of pleural changes in former workers exposed to anthophyllite associated with other contaminating amphibole asbestos in Brazil.

OBJECTIVE: To evaluate the frequency and severity of pleuropulmonary alterations in anthophyllite-exposed former workers in Itapira, São Paulo, Brazil. The amphibole anthophyllite, a magnesium-iron silicate, had its mining, marketing, and use forbidden in Brazil in 1995. METHODS: Former workers were followed from 1999 to 2011. All completed chest X-ray interpreted using the International Labour Office (ILO) classification. High-resolution computed tomography was used at the final evaluation. Spirometry assessed forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and FEV1/FVC throughout the follow-up period. Samples from the mined ore were analyzed by X-ray diffraction (XRD) and scanning electron microscopy coupled to energy dispersive spectroscopy (SEM-EDS). RESULTS: XRD and SEM-EDS confirmed the presence in ore of anthophyllite at a concentration of 75%, in addition to tremolite and other amphiboles in lower concentrations. Twenty-eight subjects were evaluated. Median time of exposure was 3 years (minimum = 1; maximum = 18; interquartile interval = 1-4). Twenty cases of pleural abnormalities were diagnosed in 26 evaluated (77%). The average latency time was 25.6 ± 7.4 years. Two individuals (7.7%) showed progressive worsening of diffuse pleural thickening (DPT) and exhibited an annual FVC decrease of 85 mL and 150 mL, respectively. CONCLUSION: This small sample showed a very high index of nonmalignant pleural abnormalities in anthophyllite-exposed workers compared with workers exposed to other kinds of fibers. Rapidly progressive DPT, defined by the severity of pleural compromise, was possibly secondary to the presence of other amphibole types in the inhaled dust. No significant loss of FVC was found in the studied group as a whole. No cases of asbestosis, lung carcinoma, and mesothelioma were diagnosed in this cohort.

Oncogenic role of arsenic exposure in lung cancer: A forgotten risk factor.

Several drinkable water sources worldwide have been highly contaminated with arsenic, which means that an estimated 160 million people have been exposed to this chemical agent. If we analyse exposure by region, we will find a high correlation between arsenic contamination and the incidence of lung cancer (among other malignancies). In order to determine what the risks of these exposures are, we need to understand how this chemical is processed in our body and how it is linked to cancer. In this article we reviewed how biotransformation of ingested arsenic may lead to cancer by modulating the activation of several essential signalling pathways such as EGFR, PI3K/AKT, RTK/Ras/PI3K, JNK/STAT3 and Nrf2-KEAP1; by producing epigenetics modifications and by disrupting normal expression of miRNAs. In order to design effective health policies, educational strategies, decontaminations plans and effective medical treatments are necessary to understand the impact of arsenic pollution and the relevance of the environment in our health.

Age at Exposure to Arsenic in Water and Mortality 30-40 Years After Exposure Cessation.

Arsenic in drinking water is known to cause cancer and noncancer diseases, but little is known about its association with age at exposure. Here, we investigated age at arsenic exposure and mortality in Antofagasta, Chile, 30-40 years after a distinct period of very high water arsenic concentrations (1958-1970). We calculated standardized mortality ratios (SMRs) comparing Antofagasta with the rest of Chile for 2001-2010 by sex and age at potential first exposure. A remarkable relationship with age at first exposure was found for bronchiectasis, with increased risk in adults 30-40 years after exposure being confined to those who were in utero (SMR = 11.7, 95% confidence interval (CI): 4.3, 25.4) or aged 1-10 years (SMR = 5.4, 95% CI: 1.1, 15.8) during the high-exposure period. Increased SMRs for lung, bladder, and laryngeal cancer were evident for exposures starting at all ages, but the highest SMRs were for exposures beginning at birth (for bladder cancer, SMR = 16.0 (95% CI: 10.3, 23.8); for laryngeal cancer, SMR = 6.8 (95% CI: 2.2, 15.8); for lung cancer, SMR = 3.8 (95% CI: 2.9, 4.9)). These findings suggest that interventions targeting early-life arsenic exposure could have major impacts in reducing long-term mortality due to arsenic 30-40 years after exposure ends.

Indoor Radon Gas (222Rn) Levels in Homes in Aldama, Chihuahua, Mexico and the Risk of Lung Cancer.

Radon (222Rn) is an odorless and tasteless gas that is known to cause lung cancer. The objective of this research was to quantify the levels of exposure to radon among people living in an environment rich in uranium (U). Radon concentrations were measured for 3 days in 12 homes in Aldama, Mexico. Homeowners agreed to participate in the study; hence, the sample was non-probabilistic. Radon was measured with a portable AlphaGuard Radon Monitor (Genicron Instruments GmbH), which was placed in a bedroom of each home at a height of 0.74 m. Gas levels were registered in Becquerels (Bq m−3), with readings taken every 10 min along with readings of ambient temperature (AT), air pressure (AP), and relative humidity (RH). We found that radon gas levels in Aldama exceed the maximum permissible limits (USA: 148 Bq m−3). Levels were higher at night, and were above the maximum permissible level recommended by the International Atomic Energy Agency of the United Nations (<200 Bq m−3). Most residents in the area have family histories of lung problems, but it was difficult to establish a strong correlation between 222Rn and lung cancer. Federal, state, and municipal governments should take stronger action to reduce the effects of radon gas on communities.

Lung, Bladder, and Kidney Cancer Mortality 40 Years After Arsenic Exposure Reduction.

Background: Region II in northern Chile (population 442 570) experienced a sudden major increase in arsenic water concentrations in 1958 in the main city of Antofagasta, followed by a major reduction in exposure when an arsenic removal plant was installed in 1970. It provides a unique opportunity to study latency effects of exposure to arsenic, and this is the first study with mortality data up to 40 years after exposure reduction. Methods: We previously identified high mortality rates in Region II up to the year 2000. Here we present rate ratios (RRs) for Region II compared with all the rest of Chile from 2001 to 2010, and with unexposed Region V (population 1 539 852) for all years from 1950 to 2010. All statistical tests were one-sided. Results: From 2001 to 2010, comparing Region II with the rest of Chile, lung and bladder mortality were still greatly elevated (RR = 3.38, 95% confidence interval [CI] = 3.19 to 3.58, P < .001 for lung cancer in men; RR = 2.41, 95% CI = 2.20 to 2.64, P < .001 for lung cancer in women; RR = 4.79, 95% CI = 4.20 to 5.46, P < .001 for bladder cancer in men; RR = 6.43, 95% CI = 5.49 to 7.54, P < .001 for bladder cancer in women). Kidney cancer mortality was also elevated (RR = 1.75, 95% CI = 1.49 to 2.05, P < .001 for men; RR = 2.09, 95% CI = 1.69 to 2.57, P < .001 for women). Earlier short latency acute myocardial infarction mortality increases had subsided. Conclusions: Lung, bladder, and kidney cancer mortality due to arsenic exposure have very long latencies, with increased risks manifesting 40 years after exposure reduction. Our findings suggest that arsenic in drinking water may involve one of the longest cancer latencies for a human carcinogen.

Effectiveness of traffic-related elements in tree bark and pollen abortion rates for assessing air pollution exposure on respiratory mortality rates.

The majority of epidemiological studies correlate the cardiorespiratory effects of air pollution exposure by considering the concentrations of pollutants measured from conventional monitoring networks. The conventional air quality monitoring methods are expensive, and their data are insufficient for providing good spatial resolution. We hypothesized that bioassays using plants could effectively determine pollutant gradients, thus helping to assess the risks associated with air pollution exposure. The study regions were determined from different prevalent respiratory death distributions in the Sao Paulo municipality. Samples of tree flower buds were collected from twelve sites in four regional districts. The genotoxic effects caused by air pollution were tested through a pollen abortion bioassay. Elements derived from vehicular traffic that accumulated in tree barks were determined using energy-dispersive X-ray fluorescence spectrometry (EDXRF). Mortality data were collected from the mortality information program of Sao Paulo City. Principal component analysis (PCA) was applied to the concentrations of elements accumulated in tree barks. Pearson correlation and exponential regression were performed considering the elements, pollen abortion rates and mortality data. PCA identified five factors, of which four represented elements related to vehicular traffic. The elements Al, S, Fe, Mn, Cu, and Zn showed a strong correlation with mortality rates (R2>0.87) and pollen abortion rates (R2>0.82). These results demonstrate that tree barks and pollen abortion rates allow for correlations between vehicular traffic emissions and associated outcomes such as genotoxic effects and mortality data.

Intranasal Administration of Type V Collagen Reduces Lung Carcinogenesis through Increasing Endothelial and Epithelial Apoptosis in a Urethane-Induced Lung Tumor Model.

Type V collagen (Col V) is a "minor" component of normal lung extracellular matrix, which is subjected to decreased and abnormal synthesis in human lung infiltrating adenocarcinoma. We previously reported that a direct link between low amounts of Col V and decreased cell apoptosis may favor cancer cell growth in the mouse lung after chemical carcinogenesis. Moreover, this collagen species was able to trigger DNA fragmentation and impair survival of neoplastic cells. In this study, we have extended our investigation with the aim to obtain further evidence that the death induced by Col V-treatment is of the caspase-9 apoptotic type. We used (1) optical and electron microscopy, (2) quantitation of TUNEL-labeled cells and (3) analysis of the expression levels of Col V and selected genes coding for apoptosis-linked factors, by conventional RT-PCR. BALB/c mice were injected intraperitoneally with 1.5 g/kg body weight of urethane. After urethane injection, the animals received intranasal administration of 20 µg/20 µl of Col V every day during 2 months. We report here that Col V treatment was able to determine significant increase in Col V protein and gene expression and in the percentage of TUNEL-positive cells, to up-regulate caspase-9, resulting in low growth of tumor cells. Our data validate chemical carcinogenesis as a suitable "in vivo" model for further and more detailed studies on the molecular mechanisms of the death response induced by Col V in lung infiltrating adenocarcinoma opening new strategies for treatment.

Multipolar mitosis and aneuploidy after chrysotile treatment: a consequence of abscission failure and cytokinesis regression.

Chrysotile, like other types of asbestos, has been associated with mesothelioma, lung cancer and asbestosis. However, the cellular abnormalities induced by these fibers involved in cancer development have not been elucidated yet. Previous works show that chrysotile fibers induce features of cancer cells, such as aneuploidy, multinucleation and multipolar mitosis. In the present study, normal and cancer derived human cell lines were treated with chrysotile and the cellular and molecular mechanisms related to generation of aneuploid cells was elucidated. The first alteration observed was cytokinesis regression, the main cause of multinucleated cells formation and centrosome amplification. The multinucleated cells formed after cytokinesis regression were able to progress through cell cycle and generated aneuploid cells after abnormal mitosis. To understand the process of cytokinesis regression, localization of cytokinetic proteins was investigated. It was observed mislocalization of Anillin, Aurora B, Septin 9 and Alix in the intercellular bridge, and no determination of secondary constriction and abscission sites. Fiber treatment also led to overexpression of genes related to cancer, cytokinesis and cell cycle. The results show that chrysotile fibers induce cellular and molecular alterations in normal and tumor cells that have been related to cancer initiation and progression, and that tetraploidization and aneuploid cell formation are striking events after fiber internalization, which could generate a favorable context to cancer development.