Rat lung response to ozone and fine particulate matter (PM2.5) exposures

Exposure to different ambient pollutants maybe more toxic to lung than exposure to a single pollutant. In this study, we discussed the inflammation and oxidative stress responses of rat lung caused by ozone and PM_2.5 versus that of rats exposed to saline, ozone, or single PM_2.5. Wistar rats inhaled 0.8 ppm ozone or air for 4 h and then placed in air for 3 h following intratracheal instillation with 0, 0.2 (low dose), 0.8 (medium dose), 3.2 (high dose) mg/rat PM_2.5 dissolved in sterile saline (0.25 mL/rat), repeated twice per week for 3 weeks, the cumulative doses of PM_2.5 in animals were 1.2, 4.8, and 19.2 mg. Rats were sacrificed 24 h after the last (sixth) exposure. The collected bronchoalveolar lavage fluid (BALF) was analyzed for inflammatory cells and cytokines. Lung tissues were processed for light microscopic and transmission electron microscopic (TEM) examinations. Results showed that total cell number in BALF of PM_2.5‐exposed groups were higher than control (p < 0.05). PM_2.5 instillation caused dose‐trend increase in tumor necrosis factor alpha (TNF‐α), interleukin‐6, lactate dehydrogenase, and total protein of BALF. Exposure to ozone alone only caused TNF‐α significant change in above‐mentioned indicators of lung injury. On the other hand, ozone could enhance PM_2.5‐induced inflammatory changes and pathological characters in rat lungs. SOD and GSH‐Px activities in lung were reduced in PM_2.5‐exposed rats with and without prior ozone exposure compared to control. To determine whether the PM_2.5 and ozone affect endothelium system, iNOS, eNOS, and ICAM‐1 mRNA levels in lung were analyzed by real‐time PCR. These data demonstrated that inflammation and oxidative stress were involved in toxicology mechanisms of PM_2.5 in rat lung and ozone potentiated these effects induced by PM_2.5. These results have implications for understanding the pulmonary effects induced by ozone and PM_2.5. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 343–356, 2015.     

eNOS gene polymorphisms modify the association of PM10 with oxidative stress

Previous studies have suggested that air pollution increases various health outcomes through oxidative stress and oxidative stress-related genes modify the relationship between air pollution and health outcomes. Therefore, we evaluated the effect of PM₁₀ on the levels of malondialdehyde (MDA), oxidative stress biomarker, and the effect modification by genetic polymorphisms of eNOS, oxidative stress-related gene, in the 560 Korean elderly. We obtained urine samples repeatedly from participants during five medical examinations between 2008 and 2010 and all ambient air pollutant concentration data from the Korea National Institute of Environmental Research air quality monitoring system. We measured urinary levels of MDA to assess oxidative stress and genotyped eNOS (rs1799983, rs2853796, and rs7830). Mixed-effect model was used to estimate the effect of PM₁₀ on the level of oxidative stress biomarker and their modification by genotypes. PM₁₀ showed apparent positive effect on MDA level after adjusting for age, sex, BMI, cotinine level, temperature, dew point, levels of SO₂, O₃, NO₂, and CO, and season (p = 0.0133). Moreover, the association of PM₁₀ with MDA was found only in participants with eNOS GG genotype for rs1799983 (p = 0.0107), TT genotype for rs2853796 (p = 0.0289), or GT genotype for rs7830 (p = 0.0158) and in participants with a set of risky haplotypes (GTT, GTG, GGT, and TGT) (p = 0.0093). Our results suggest that PM₁₀ affect oxidative stress in the elderly and eNOS genotype affect the oxidative stress level in regard of exposure to PM₁₀.     

Alteration of cardiac function in ApoE−/− mice by subchronic urban and regional inhalation exposure to concentrated ambient PM2.5

Ambient PM_2.5 (particulate matter with an aerodynamic diameters of less than 2.5 μm) is associated with alterations in the autonomic nervous system and cardiac function, but there are significant response variations. The authors simultaneously studied the effects of concentrated PM_2.5 (CAPs) in Sterling Forest (SF; dominated by long-range transported PM) and at the Mount Sinai School of Medicine (MS; rich in Ni and elemental/organic carbon [EC/OC]) in Manhattan, NY. ApoE^?/? mice (n?=?8/group) were exposed to filtered air or CAPs (average 133 and 123 μg/m³ in SF and MS, respectively) for 6?h/day, 5 days/week for 6 months. Electrocardiogram (ECG) tracings were monitored using telemetry. At MS, current day CAPs mass was negatively associated with short-term changes in heart rate (HR), and positively with HR variability (HRV). At SF, CAPs mass was positively associated with HR, and negatively with HRV. At MS, HR and HRV changes were associated with PM_2.5 components associated with redisual oil combustion?>?long-range transport?>?traffic?>?FeMn?>?incineration?>?soil, and fireworks had no associations. At SF, HR and HRV were associated with long-range transport?>?Ni refinery?>?soil?>?residual oil combustion/traffic. At both sites, there were cardiac function associations with PM_2.5, but not EC. At MS, there were associations with Ni and P, whereas at SF, they were with a mixture of long-range transported PM, crustal material, and combustion products. Thus subchronic CAPs exposures at locations with different particle compositions produced different effects on cardiac function in ApoE^?/? mice.     

Statins attenuate the development of atherosclerosis and endothelial dysfunction induced by exposure to urban particulate matter (PM10)

Exposure to ambient air particulate matter (particles less than 10 μm or PM₁₀) has been shown to be an independent risk factor for the development and progression of atherosclerosis. The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have well-established anti-inflammatory properties. The aim of this study was to determine the impact of statins on the adverse functional and morphological changes in blood vessels induced by PM₁₀. New Zealand White rabbits fed with a high fat diet were subjected to balloon injury to their abdominal aorta followed by PM₁₀/saline exposure for 4 weeks ± lovastatin (5 mg/kg/day) treatment. PM₁₀ exposure accelerated balloon catheter induced plaque formation and increased intimal macrophages and lipid accumulation while lovastatin attenuated these changes and promoted smooth muscle cell recruitment into plaques. PM₁₀ impaired vascular acetylcholine (Ach) responses and increased vasoconstriction induced by phenylephrine as assessed by wire myograph. Supplementation of nitric oxide improved the impaired Ach responses. PM₁₀ increased the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in blood vessels and increased the plasma levels of endothelin-1 (ET-1). Incubation with specific inhibitors for iNOS, COX-2 or ET-1 in the myograph chambers significantly improved the impaired vascular function. Lovastatin decreased the expression of these mediators in atherosclerotic lesions and improved endothelial dysfunction. However, lovastatin was unable to reduce blood lipid levels to the baseline level in rabbits exposed to PM₁₀. Taken together, statins protect against PM₁₀-induced cardiovascular disease by reducing atherosclerosis and improving endothelial function via their anti-inflammatory properties.     

Beijing ambient particle exposure accelerates atherosclerosis in ApoE knockout mice

Background

Air pollution is associated with significant adverse health effects including increased cardiovascular morbidity and mortality. However research on the cardiovascular effect of “real-world” exposure to ambient particulate matter (PM) in susceptible animal model is very limited. In this study, we aimed to investigate the association between Beijing ambient particle exposure and the atherosclerosis development in the apolipoprotein E knockout mice (ApoE^−/− mice).

Methods

Two parallel exposure chambers were used for whole body exposure among ApoE knockout mice. One of the chambers was supplied with untreated ambient air (PM group) and the other chamber was treated with ambient air filtered by high-efficiency particulate air (HEPA) filter (FA group). Twenty mice were divided into two groups and exposed to ambient PM (n = 10 for PM group) or filtered air (n = 10 for FA group) for two months from January 18th to March 18th, 2010. During the exposure, the mass concentrations of PM_2.5 and PM₁₀ in the two chambers were continuously monitored. Additionally, a receptor source apportionment model of chemical mass balance using 19 organic tracers was applied to determine the contributions of sources on the PM_2.5 in terms of natural gas, diesel vehicle, gasoline vehicle, coal burning, vegetable debris, biomass burning and cooking. At the end of the two-month exposure, biomarkers of oxidative stress, inflammation and lipid metabolism in bronchoalveolar lavage fluid (BAL) and blood samples were determined and the plaque area on the aortic endothelium was quantified.

Results

In the experiment, the concentrations of PM₁₀ and PM_2.5 in PM chamber were 99.45 μg/m³ and 61.0 μg/m³ respectively, while PM_2.5 in FA chamber was 17.6 μg/m³. Source apportionment analysis by organic tracers showed that gasoline vehicle (39.9%) and coal burning (24.3%) emission were the two major sources contributing to the mass concentration of PM_2.5 in Beijing. Among the ApoE knockout mice, the PM group were significantly higher than the FA group in terms of serum total cholesterol, low-density lipoprotein, tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein as well as TNF-alpha and interleukin-6 in BAL. Also the total antioxidant capacity and oxidized low-density lipoprotein were significantly different between the two groups. In addition, pathological analysis of aortic arch reveals that the plaques area in the PM group increased significantly compared to the FA group.

Conclusions

Our results demonstrated that ambient PM exposure could induce considerable oxidative stress and systemic inflammation in ApoE knockout mice and contribute to the progression of atherosclerosis.     

Cytoplasmic p21, ERK1/2 activation,and cytoskeletal remodeling are associated with the senescence-like phenotype after airborne particulate matter (PM10) exposure in lung cells

The exposure to particulate matter with a mean aerodynamic diameter ≤10 μm (PM₁₀) from urban zones is considered to be a risk factor in the development of cancer. The aim of this work was to determine if PM₁₀ exposure induces factors related to the acquisition of a neoplastic phenotype, such as cytoskeletal remodeling, changes in the subcellular localization of p21^CIP1/WAF1, an increase in β-galactosidase activity and changes in cell cycle. To test our hypothesis, PM₁₀ from an industrial zone (IZ) and a commercial zone (CZ) were collected, and human adenocarcinoma lung cell cultures (A549) were exposed to a sublethal PM₁₀ concentration (10 μg/cm²) for 24 h and 48 h. The results showed that PM₁₀ exposure induced an increase in F-actin stress fibers and caused the cytoplasmic stabilization of p21^CIP1/WAF1 via phosphorylation at Thr¹⁴⁵ and Ser¹⁴⁶ and the phosphorylation of ERK1/2 on Thr²⁰². Changes in the cell cycle or apoptosis were not observed, but an increase in β-galactosidase activity was detected. The PM₁₀ from CZ caused more dramatic effects in lung cells. We conclude that PM₁₀ exposure induced cytoplasmic p21^CIP1/WAF1 retention, ERK1/2 activation, cytoskeleton remodeling and the acquisition of a senescence-like phenotype in lung cells. These alterations could have mechanistic implications regarding the carcinogenic potential of PM₁₀.     

Synergistic effects of exposure to concentrated ambient fine pollution particles and nitrogen dioxide in humans

Context: Exposure to single pollutants e.g. particulate matter (PM) is associated with adverse health effects, but it does not represent a real world scenario that usually involves multiple pollutants.

Objectives: Determine if simultaneous exposure to PM and NO₂ results in synergistic interactions.

Materials and methods: Healthy young volunteers were exposed to clean air, nitrogen dioxide (NO₂, 0.5 ppm), concentrated fine particles from Chapel Hill air (PM_2.5CAPs, 89.5?±?10.7 µg/m³), or NO₂+PM_2.5CAPs for 2?h. Each subject performed intermittent exercise during the exposure. Parameters of heart rate variability (HRV), changes in repolarization, peripheral blood endpoints and lung function were measured before and 1 and 18?h after exposure. Bronchoalveolar lavage (BAL) was performed 18?h after exposure.

Results: NO₂ exposure alone increased cholesterol and HDL 18?h after exposure, decreased high frequency component of HRV one and 18?h after exposure, decreased QT variability index 1?h after exposure, and increased LDH in BAL fluid. The only significant change with PM_2.5CAPs was an increase in HDL 1?h after exposure, likely due to the low concentrations of PM_2.5CAPs in the exposure chamber. Exposure to both NO₂ and PM_2.5CAPs increased BAL α1-antitrypsin, mean t wave amplitude, the low frequency components of HRV and the LF/HF ratio. These changes were not observed following exposure to NO₂ or PM_2.5CAPs alone, suggesting possible interactions between the two pollutants.

Discussion and conclusions: NO₂ exposure may produce and enhance acute cardiovascular effects of PM_2.5CAPs. Assessment of health effects by ambient PM should consider its interactions with gaseous copollutants.     

Airway effects of repeated exposures to ozone-initiated limonene oxidation products as model of indoor air mixtures

Repeated low-level indoor air exposure to volatile organic compounds (VOCs) may influence the reporting of sensory irritation in the eyes and airways. The ozone-initiated reaction products of limonene, an abundant VOC, were used as a model of indoor air mixtures to study upper airway (sensory) irritation, bronchoconstrictive and alveolar level effects after repeated exposures. Mice were exposed 1 h/day for 10 consecutive days to: air, limonene (52 ppm/289 mg/m³); ozone (0.1 ppm/0.2 mg/m³); a reaction mixture of limonene (52 ± 8 ppm) and ozone (0.5, 2.5 and 3.9 ppm) resulting in ∼0.05 ppm residual ozone. Neither the limonene nor the ozone exposures alone showed consistent effects on the respiratory parameters. In the limonene/ozone groups, the respiratory rate decreased concentration-dependently with an extrapolated no-effect-level of ∼0.3 ppm admixed ozone. Both sensory irritation and airflow limitation were conspicuous effects of the mixtures; sensory irritation appeared rapidly and airflow limitation developed slowly during each exposure. The effects of these parameters did not change with increasing number of exposures. No firm conclusion could be drawn about alveolar level effects. Cells in bronchoalveolar lavage were unchanged irrespective of exposure to air, ozone, and limonene with and without ozone. In conclusion, the study indicated that repeated exposures to ozone-initiated limonene mixtures did not cause sensitization of sensory irritation and airflow limitation. Bronchoalveolar lavage after exposures to ozone, and limonene with and without ozone, respectively, did not show airway inflammation.     

Aflatoxin B1 and fumonisin B1 affect the oxidative status of bovine peripheral blood mononuclear cells

Mycotoxins are secondary metabolites having a high cytotoxic potential. They are produced by molds and released in food and feed. To date, the mechanisms underlying the mycotoxin-induced cytotoxicity have not been fully clarified. The induction of oxidative stress, as a possible mechanism, has been postulated. This in vitro study was focused on the effect of two widely occurring mycotoxins, aflatoxin B₁ (AFB₁) and fumonisin B₁ (FB₁), on the oxidative status of bovine peripheral blood mononuclear cells (PBMC) incubated for 2 and 7 days at different levels of AFB₁ (0, 5 and 20 μg/ml) and FB₁ (0, 35 and 70 μg/ml). Reactive oxygen metabolites (ROM), intracellular thiols (SH), malondialdehyde (MDA) and gene expression of cytoplasmic superoxide dismutase (SOD) and glutathione peroxidase (GSHPX-1) were measured on PBMC after incubation. The highest concentration of AFB₁ and all concentrations of FB₁ caused an increase (p < 0.05) of intracellular ROM without any time dependent effect. Intracellular SH decreased with 20 μgAFB₁/ml (p < 0.05) and the effect was particularly marked after 7 days of exposure. Intracellular SH were not affected by FB₁ even though a lower (p < 0.05) SH level after 2 days exposure than after 7 days was observed. MDA increased (p < 0.05) in AFB₁ or FB₁ treated PBMC. The exposure to FB₁ for 7 days increased MDA (p < 0.05) only in cells treated with 70 μg/ml. Exposure of PBMC to AFB₁ reduced SOD mRNA while FB₁ decreased both SOD and GSHPX-1 mRNA abundance. These results demonstrate that, even though by different mechanisms, AFB₁ and FB₁ may induce cytotoxicity through an impairment of the oxidative status of PBMC.     

Systemic inflammatory changes and increased oxidative stress in rural Indian women cooking with biomass fuels

The study was undertaken to investigate whether regular cooking with biomass aggravates systemic inflammation and oxidative stress that might result in increase in the risk of developing cardiovascular disease (CVD) in rural Indian women compared to cooking with a cleaner fuel like liquefied petroleum gas (LPG). A total of 635 women (median age 36 years) who cooked with biomass and 452 age-matched control women who cooked with LPG were enrolled. Serum interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α) and interleukin-8 (IL-8) were measured by ELISA. Generation of reactive oxygen species (ROS) by leukocytes was measured by flow cytometry, and erythrocytic superoxide dismutase (SOD) was measured by spectrophotometry. Hypertension was diagnosed following the Seventh Report of the Joint Committee. Tachycardia was determined as pulse rate > 100 beats per minute. Particulate matter of diameter less than 10 and 2.5 μm (PM₁₀ and PM_2.5, respectively) in cooking areas was measured using real-time aerosol monitor. Compared with control, biomass users had more particulate pollution in indoor air, their serum contained significantly elevated levels of IL-6, IL-8, TNF-α and CRP, and ROS generation was increased by 37% while SOD was depleted by 41.5%, greater prevalence of hypertension and tachycardia compared to their LPG-using neighbors. PM₁₀ and PM_2.5 levels were positively associated with markers of inflammation, oxidative stress and hypertension. Inflammatory markers correlated with raised blood pressure. Cooking with biomass exacerbates systemic inflammation, oxidative stress, hypertension and tachycardia in poor women cooking with biomass fuel and hence, predisposes them to increased risk of CVD development compared to the controls. Systemic inflammation and oxidative stress may be the mechanistic factors involved in the development of CVD.     

Effects of acute in vitro exposure of murine precision-cut lung slices to gaseous nitrogen dioxide and ozone in an air–liquid interface (ALI) culture

The aim of this study was to establish an air–liquid interface (ALI) culture of precision-cut lung slices (PCLS) for direct exposure of lung cells to gaseous contaminants. Nitrogen dioxide (NO₂) and ozone (O₃) were selected as model gas compounds. Acute pro-inflammatory and toxic effects of NO₂ and O₃ on live lung tissue were investigated. Murine PCLS were exposed to different flow rates (3–30 mL/min) of synthetic air, O₃ (3.5–8.5 ppm), or NO₂ (1–80 ppm). Tissue survived ex vivo in ALI culture and resisted exposure to NO₂ (1–10 ppm) and O₃ (3.5–8.5 ppm) for 1 h. Longer exposure to NO₂ resulted in a clear loss of viability, whereas exposure to O₃ was less effective. Exposure to NO₂ dose-dependently induced release of the pro-inflammatory IL-1α (40%), whereas RANTES, IL-12, and eotaxin remained unchanged. Early secretion of IL-1α (80%), RANTES (>800%), MIP-1β (44%), and MCP-1 (60%) was already detected after 1 h of exposure to O₃. The obtained data showed that direct exposure to O₃ and NO₂ induced cytotoxicity and pro-inflammatory responses in PCLS with ALI culture. This provides a model that more closely resembles in vivo exposure of airborne contaminants, and thus should be appropriate for toxicity testing.     

Individual fumonisin exposure and sphingoid base levels in rural populations consuming maize in South Africa

Low and high oesophageal cancer incidence areas of the former Transkei region of South Africa have been associated with corresponding low and high levels of fumonisin contaminated home-grown maize. This is the first study in South Africa assessing fumonisin B (FB) mycotoxin exposure by quantifying individual maize consumption with weighed food records and FB levels from maize in each participant’s household and concurrently evaluating sphinganine (Sa), sphingosine (So) and Sa/So ratios in plasma and urine of these participants as possible biomarkers of FB exposure. The high consumption of maize in Bizana (n = 36) and Centane (n = 30) of 0.41 ± 0.21 and 0.39 ± 0.19 kg/day, respectively, confirms the reliance on maize as the dietary staple. Mean total FB (FB₁ + FB₂ + FB₃) levels in home-grown maize were 0.495 + 0.880 and 0.665 + 0.660 mg/kg in Bizana and Centane, respectively. Mean fumonisin exposure based on individual consumption was 3.9 ± 7.3 and 4.1 ± 7.6 μg/kg body weight/day, respectively, for Bizana and Centane. The mean combined sphinganine/sphingosine ratios in Bizana and Centane were similar and ranged from 0.10–0.55 in plasma (n = 41) and urine (n = 62). There was no association between sphingoid base levels and/or Sa/So ratios in the plasma and urine and individual fumonisin exposure, negating the sphingoid bases as potential biomarkers of fumonisin exposure in humans.     

Winter fine particulate matter from Milan induces morphological and functional alterations in human pulmonary epithelial cells (A549)

Samples of PM_2.5 were gravimetrically collected during the winter 2005/2006 in the urban area of Milan (North Italy). Samples were chemically characterized and the particles were detached from filters to determine their cytotoxic effects on the A549 cell line. Based on the potential toxicological relevance of its components, Milan winter PM_2.5 contained high concentrations of pro-oxidant transition metals and PAHs, while re-suspended particles showed a relatively high frequency of dimensional classes ranging from 40 nm to 300 nm.     

Association of systemic inflammation with marked changes in particulate air pollution in Beijing in 2008

Many studies have linked ambient fine particulate matter (aerodynamic diameters less than 2.5 μm, PM_2.5) air pollution to increased morbidity and mortality of cardiovascular diseases in the general population, but the biologic mechanisms of these associations are yet to be elucidated. In this study, we aimed to evaluate the relationship between daily variations in exposure to PM_2.5 and inflammatory responses in mice during and for 2 months after the Beijing Olympic Games. Male C57BL/6 mice were exposed to Beijing PM_2.5 or filtered air (FA) in 2008 during the 2 months of Beijing Olympic and Paralympic Games, and for 2 months after the end of the Games. During the Games, circulating monocyte chemoattractant protein 1 and interleukin 6 were increased significantly in the PM_2.5 exposure group, when compared with the FA control group, although there were no significant inter-group differences in tumor necrosis factor-α or interferon-γ, or in macrophages, neutrophils or lymphocytes in the spleen or thymus between these 2 groups. However, macrophages were significantly increased in the lung and visceral fat with increasing PM_2.5. After the Olympic Games, there were no significant PM_2.5-associated differences for macrophages, neutrophils or lymphocytes in the thymus, but macrophages were significantly elevated in the lung, spleen, subcutaneous and visceral fat with increasing PM_2.5, and the numbers of macrophages were even higher after than those during the Games. Moreover, the number of neutrophils was markedly higher in the spleen for the PM_2.5-exposed- than the FA-group. These data suggest that short-term increases in exposure to ambient PM_2.5 leads to increased systemic inflammatory responses, primarily macrophages and neutrophils in the lung, spleen, and visceral adipose tissue. Short-term air quality improvements were significantly associated with reduced overall inflammatory responses.     

Inflammatory markers and exposure to occupational air pollutants

Objectives: To study the possible relationship between inhalation of airborne particles in the work environment and inflammatory markers in blood.

Methods: Total dust was sampled in the breathing zone of 73 subjects working with welding, cutting, grinding and in foundries such as iron, aluminium, and concrete. Stationary measurements were used to study different size fractions of particles including respirable dust, particulate matter (PM)₁₀ and PM_2.5, the particle number concentration, the number of particles deposited in the alveoli, and total particle surface area concentration. Inflammatory markers such as interleukin-6 (IL-6), C-reactive protein (CRP), fibrinogen, d-dimer, and urate were measured in plasma or serum before the first shift after the summer vacation and after the first, second, and fourth shift.

Results: The mean level of total dust in the breathing zone was 0.93?mg/m³. The proxies for mean respirable dust fraction was 0.27?mg/m³, PM₁₀ 0.60?mg/m³, and PM_2.5 was 0.31?mg/m³. The IL-6 values increased by 50% after the first day, but decreased after shift on the second and fourth day. CRP did not increase after the first shift but increased by 17% after the second shift. Other biomarkers were unaffected. A multiple linear regression analysis of a subgroup of 47 subjects showed a statistically significant positive relationship between particle exposure and post-shift IL-6.

Conclusion: This study supports previous investigations observing increases of IL-6 at air concentrations of PM₁₀ or PM_2.5 between 0.13 and 0.3?mg/m³ among healthy subjects. This increase of IL-6 may indicate an increased risk of coronary heart disease.     

Evaluation of in vitro cytotoxicity of 6-benzylaminopurine carboplatin derivatives against human cancer cell lines and primary human hepatocytes

A series of seven platinum(II) cyclobutane-1,1-dicarboxylato (cbdc) complexes {[Pt(cbdc)(L_n)₂], 1-7}, derived from carboplatin by a substitution of two NH₃ molecules for two 2,6,9-trisubstituted 6-benzylaminopurine-based N-donor ligands (L_n), was studied by the MTT assay for their in vitro cytotoxic activity against seven human cancer cell lines, i.e. lung carcinoma (A549), cervix epithelioid carcinoma (HeLa), osteosarcoma (HOS), malignant melanoma (G361), breast adenocarcinoma (MCF7), ovarian carcinoma (A2780) and its cisplatin-resistant analogue (A2780cis), and against two primary cultures of human hepatocytes (LH31 and LH32). The prepared complexes were cytotoxic against several cancer cells, in some cases even more than cisplatin. The best results were achieved for complexes 1 (IC₅₀ = 17.4 ± 2.0 μM) and 2 (IC₅₀ = 14.8 ± 2.1 μΜ) against HOS cells, 1 (IC₅₀ = 15.1 ± 6.8 μM), 2 (IC₅₀ = 13.6 ± 5.2 μM) and 6 (IC₅₀ = 19.0 ± 6.6 μM) against MCF7, 6 (IC₅₀ = 6.4 ± 0.1 μM) against A2780, and 1-6 (IC₅₀ = 15.6 ± 4.0, 12.9 ± 3.7, 15.8 ± 3.8, 16.6 ± 5.5, 22.1 ± 2.5, and 5.6 ± 1.7 μM, respectively) against A2780cis. Viability of human hepatocytes was not declined by the tested complexes up to the concentration of 50 μM (for 1, 3-7) and 20 μM (for 2; caused by lower solubility of this complex).