Environmental risk assessment of anti-cancer drugs and their transformation products: A focus on their genotoxicity characterization-state of knowledge and short comings

Toxicological evaluation of imidazo-based heterocyclic derivatives: In-vitro and in-vivo acute toxicity studies

Imidazo based heterocyclic derivatives are considered as privileged scaffolds due to their presence in various pharmacologically active compounds and in marketed formulations. The present study reports toxicological evaluation of three imidazo based heterocyclic derivatives which are currently being investigated for their potential anticancer activity. Compounds IG-01-007, IG-01-008, and IG-01-009 were assessed for cytotoxicity, hemolysis, and DNA fragmentation activity. Acute oral toxicity studies were performed at doses of 300 mg/kg and 1000 mg/kg according to OECD guidelines, in both male and female Wistar rats. All test compounds at a concentration of 50 µM resulted in DNA fragmentation suggesting notable impact on DNA integrity. The in-vivo acute toxicity study indicated significant toxicity at doses of ≥ 1000 mg/kg, particularly for compounds IG-01-008 and IG-01-009, which caused hepatic damage and cholestasis in liver tissues. These results collectively suggest that imidazo based heterocyclic derivatives used in the present study exhibit cytotoxic potential.

Marine Resources Offer New Compounds and Strategies for the Treatment of Skin and Soft Tissue Infections

Bioprospecting of the marine environment for drug development has gained much attention in recent years owing to its massive chemical and biological diversity. Drugs for the treatment of skin and soft tissue infections have become part of the search, mainly with respect to enlarging the number of available antibiotics, with a special focus on multidrug-resistant Gram-positive bacteria, being the major causative agents in this field. Marine resources offer novel natural products with distinct biological activities of pharmaceutical importance, having the chance to provide new chemical scaffolds and new modes of action. New studies advance the field by proposing new strategies derived from an ecosystemic understanding for preventive activities against biofilms and new compounds suitable as disinfectants, which sustain the natural flora of the skin. Still, the development of new compounds is often stuck at the discovery level, as marine biotechnology also needs to overcome technological bottlenecks in drug development. This review summarizes its potential and shows these bottlenecks and new approaches.

TiO2 based Photocatalysis membranes: An efficient strategy for pharmaceutical mineralization

Among the various emerging contaminants, pharmaceuticals (PhACs) seem to have adverse effects on the quality of water. Even the smallest concentration of PhACs in ground water and drinking water is harmful to humans and aquatic species. Among all the deaths reported due to COVID-19, the mortality rate was higher for those patients who consumed antibiotics. Consequently, PhAC in water is a serious concern and their removal needs immediate attention. This study has focused on the PhACs' degradation by collaborating photocatalysis with membrane filtration. TiO₂-based photocatalytic membrane is an innovative strategy which demonstrates mineralization of PhACs as a safer option. To highlight the same, an emphasis on the preparation and reinforcing properties of TiO₂-based nanomembranes has been elaborated in this review. Further, mineralization of antibiotics or cytostatic compounds and their degradation mechanisms is also highlighted using TiO₂ assisted membrane photocatalysis. Experimental reactor configurations have been discussed for commercial implementation of photoreactors for PhAC degradation anchored photocatalytic nanomembranes. Challenges and future perspectives are emphasized in order to design a nanomembrane based prototype in future for wastewater management.

Highly dispersed Ag and g-C3N4 quantum dots co-decorated 3D hierarchical Fe3O4 hollow microspheres for solar-light-driven pharmaceutical pollutants degradation in natural water matrix

The efficient removal of pharmaceutical pollutants presents a great challenge for the conventional sewage treatment system. Herein, we document the nanosheets assembled 3D hierarchical Fe₃O₄ hollow microspheres co-modified by Ag and g-C₃N₄ quantum dots (Ag/CNQDs@Fe₃O₄) for efficient degradation of two classic anticancer drugs, i.e., capecitabine (CAP) and 5-fluorouracil (5-FLU) under visible light in 1 h. Benefiting from the unique hierarchically hollow structure, the intrinsic strengths of each component and their interactions, synergistic reinforcing mechanism is constructed, furnishing more accessible reactive places, promoting the diffusion of pollutants/oxidants, improving charge separation ability, and raising light utilization rate. Consequently, Ag/CNQDs@Fe₃O₄ can not only show superior photocatalytic properties, but also greatly boost PMS activation to yield sufficient oxidative radicals. More notably, the studied system also features excellent stability and strong tolerance to real water samples, and maintains appreciable performance even under natural sunlight illumination. The predominant active species, possible ADs decomposition pathways, and underlying reaction mechanism for the Ag/CNQDs@Fe₃O₄/PMS/vis system are thoroughly explored. This work presents significant advancement in enabling an integrated technology of PMS and photocatalysis to realize its great potential in environment restoration.

Transformation products of sulfonamides in aquatic systems: Lessons learned from available environmental fate and behaviour data

Sulfonamides (SUAs) and their transformation products (TPs) contribute to environmental pollution. Importance of research on TPs' properties has been emphasised, e.g. allowing a comprehensive environmental risk assessment of their parent compounds. However, TPs' properties have been discussed in reviews on SUAs only marginally, if at all. For the first time, a scientific literature review aims to discuss the current state of knowledge on SUA-TPs including research gaps, and commonalities of SUA-TPs and TPs in general. Literature on SUA-TPs was consulted systematically to collect data on occurrence, physicochemical properties, degradability, and (eco)toxicity. TPs of 14 SUAs were reviewed, and aspects applicable for TPs in general were identified to guide future handling of TPs as a complex category of compounds. The data of sulfamethoxazole (SMX), the main representative, was analysed in more detail to discuss insights on a chemical level. Literature search resulted in 607 SUA-TPs reported in 222 publications. Only for 4%, 31%, and 35% of these TPs, data on occurrence in aquatic systems, on degradation, and (eco)toxicity, respectively, was found. Several mixtures of SUA-TPs were more ecotoxic than their parent compounds, e.g. 10 of 15 mixtures of SMX-TPs. Only few TPs were tested as single substance. Although several TPs could be eliminated experimentally, their mineralisation rate remained often unknown. Thus, further transformation to persistent TPs could not be ruled out. Standardised biodegradability tests of individual TPs would monitor their mineralisation rate, but are almost completely lacking. Reasons are likely poor availability of TPs, but also the focus on abiotic water treatment. Data assessment demonstrated that data of high significance according to standard methods, e.g. OECD methods for chronic (eco)toxicity and ready biodegradability, is needed to assess environmental risks of prioritised TPs, but also to redesign their parent pharmaceutical for complete environmental mineralisation in a long-term (Benign by Design).

RETRACTED: Environmental Risk Assessment of Dexamethasone Sodium Phosphate and Tocilizumab Mixture in Zebrafish Early Life Stage (Danio rerio)

Pharmaceuticals are widely regarded as a menace to the aquatic environment. The constant consumption of biologically active chemicals for human health has been matched by an increase in the leaking of these compounds in natural habitats over the last two decades. This study was aimed to evaluate the molecular pathway underling the developmental toxicity of exposure in the ecological environment. Zebrafish embryos were exposed at doses of dexamethasone sodium phosphate (DEX) 1 μmol/L, tocilizumab 442.1 μmol/L and dexamethasone + tocilizumab (1 μmol/L and 442.1 μmol/L, respectively) from 24 h post-fertilization (hpf) to 96 hpf. This study confirmed that DEX exposure in association with tocilizumab 442.1 μmol/L at 1 μmol/L (non-toxic concentration) affected the survival and hatching rate, morphology score, and body length. Additionally, it significantly disturbed the antioxidant defense system in zebrafish larvae. Furthermore, a DEX 1 μmol/L and tocilizumab 442.1 μmol/L association also increased the production of apoptosis-related proteins (caspase-3, bax, and bcl-2).

Persistence, environmental hazards, and mitigation of pharmaceutically active residual contaminants from water matrices

Pharmaceutical compounds are designed to elicit a biological reaction in specific organisms. However, they may also elicit a biological response in non-specific organisms when exposed to ambient quantities. Therefore, the potential human health hazards and environmental effects associated with pharmaceutically active compounds presented in aquatic environments are being studied by researchers all over the world. Owing to their broad-spectrum occurrence in various environmental matrices, direct or indirect environmental hazardous impacts, and human-health related consequences, several pharmaceutically active compounds have been categorized as emerging contaminants (ECs) of top concern. ECs are often recalcitrant and resistant to abate from water matrices. In this review, we have examined the classification, occurrence, and environmental hazards of pharmaceutically active compounds. Moreover, because of their toxicity and the inefficiency of wastewater treatment plants to remove pharmaceutical pollutants, novel wastewater remediation technologies are urgently required. Thus, we have also analyzed the recent advances in microbes-assisted bioremediation as a suitable, cost-effective, and eco-friendly alternative for the decontamination of pharmaceutical pollutants. Finally, the most important factors to reach optimal bioremediation are discussed.

The interplay between anticancer challenges and the microbial communities from the gut

Cancer being an increasing burden on human health, the use of anticancer drugs has risen over the last decades. The physiological effects of these drugs are not only perceived by the host's cells but also by the microbial cells it harbors as commensals, notably the gut microbiota. Since the early '50 s, the cytotoxicity of anticancer chemotherapy was evaluated on bacteria revealing some antimicrobial activities that result in an established perturbation of the gut microbiota. This perturbation can affect the host's health through dysbiosis, which can lead to multiple complications, but has also been shown to have a direct effect on the treatment efficiency.We, therefore, conducted a review of literature focusing on this triangular relationship involving the microbial communities from the gut, the host's disease, and the anticancer treatment. We focused specifically on the antimicrobial effects of anticancer chemotherapy, their impact on mutagenesis in bacteria, and the perspectives of using bacteria-based tools to help in the diagnostic and treatment of cancer.

Sensitivity of Zebrafish Embryogenesis to Risk of Fotemustine Exposure

Several anthropogenic products in wastewater are considered a threat to the aquatic environment. In addition to common industrial pollutants, levels of pharmaceuticals have been increasingly found in the environment in recent years, which may present a strong risk to the aquatic species that live there. The constant consumption of biologically active chemicals for human health has been matched by an increase in the leaking of these compounds in natural habitats over the last two decades. This study is aimed at evaluating the developmental toxicity of fotemustine in the ecological environment. Zebrafish embryos were exposed to doses of 25, 50 and 100 µg/mL from 4 h post-fertilization to 120 h. This study confirms that fotemustine exposure at 50 and 100 µg/mL affects the survival and hatching rate, morphology score and body length. Additionally, it significantly disturbs the antioxidant defense system and increases ROS in zebrafish larvae. From the molecular point of view, fotemustine exposure strongly induces apoptosis, endoplasmic reticulum stress (ERS) and the Wnt signaling pathway.

Nanohybrids-assisted photocatalytic removal of pharmaceutical pollutants to abate their toxicological effects - A review

Advancement in medication by health care sector has undoubtedly improved our life but at the same time increased the chemical burden on our natural ecosystem. The residuals of pharmaceutical products become part of wastewater streams by different sources such as excretion after their usage, inappropriate way of their disposal during production etc. Hence, they are serious health hazards for human, animal, and aquatic lives. Due to rapid urbanization, the increased demand for clean drinking water is a burning global issue. In this regard it is need of the present era to explore efficient materials which could act as photocatalyst for mitigation of pharmaceuticals in wastewater. Nanohybrid as photocatalyst is one of the widely explored class of materials in photocatalytic degradation of such harmful pollutants. Among these nanohybrids; metal based nanohybrids (metals/metal oxides) and carbon based nanohybrids (carbon nanotubes, graphene, fullerenes etc.) have been explored to remove pharmaceutical drugs. Keeping in view the increasing harmful impacts of pharmaceuticals; the sources of pharmaceuticals in wastewater, their health risk factors and their mitigation using efficient nanohybrids as photocatalysts have been discussed in this review.

Cyclophosphamide affects eye development and locomotion in zebrafish (Danio rerio)

Cyclophosphamide (CP) is a broad-spectrum anticancer drug and has been frequently detected in aquatic environments due to its incomplete removal by wastewater treatment facilities and slow degradation in waters. Its toxicity in fish remains largely unknown. In this study, zebrafish eggs <4 h post fertilization (hpf) were exposed to CP at the concentrations from 0.5 to 50.0 μg/L until 168 hpf, and its toxicity was evaluated by biochemical, transcriptomic, and behavioral approaches. The results showed that malformation and mortality rates increased with CP concentrations. The 7-day malformation EC₅₀ and mortality (LC₃₀) by CP were calculated to be 86.8 μg/L and 7.5 mg/L, respectively. Inhibited startle response (light to dark) (a minimal of 19%) and reduced swimming velocity (a minimal of 30%) were observed in the CP-exposed larvae. The thicknesses of retinal ganglion layer, inner plexiform layer, and inner nuclear layer in the retina were increased after exposure to CP. Meanwhile, exposure to CP increased karyorrhexis and karyolysis in the liver tissue. Transcriptomic analysis identified 607 differentially expressed genes (DEGs) (159 up-regulated and 448 down-regulated). A significant reduction in the transcripts of sgk1 (the FoxO pathway), jun (the MAPK pathway), and diabloa (apoptosis pathway) were observed in the CP-treated larvae. This study has demonstrated that low concentrations of CP cause malformation, reduced swimming capacity, histopathological alterations in the retina and liver tissues, and interference on transcriptional expressions of key genes associated with different pathways. The ecological risk of CP and other anticancer drugs to aquatic organisms merits future investigation.

Aquatic ecotoxicology of anticancer drugs: A systematic review

Anticancer drugs in the aquatic environment have drawn a lot of attention in the last decade. Since wastewater treatment plants are inefficient at fully eliminating trace concentrations of anticancer drugs, these compounds are continuously discharged into the aquatic environment. Subsequently, non-target organisms such as the aquatic biota are directly exposed to a variety of anticancer drugs. To understand the potential impact on the aquatic organisms, a systematic review was conducted in compliance with the PRISMA guidelines. The results acquired from the 152 included studies were analysed and sorted into four categories: the impact of each included anticancer drug, the effect of metabolites, the effect of a mixture of drugs, and risk assessment. Findings showed that risk to the aquatic biota was unlikely to occur as the concentrations needed to induce effects were much higher than those detected in the environment. However, these data were based on acute toxicity and included only basic toxicity endpoints. The concentrations that produced significant effects were much lower when tested in the long-term or in multi-generational studies. Heterogeneity in results was also observed; this depended on the organism tested, the assessment adopted, and the endpoints selected. In this systematic review, an overall view of the research studies was generated by which all the variability factors to be considered were reported and recommendations to guide future studies were proposed.

Treatment-driven removal efficiency, product formation, and toxicity evolution of antineoplastic agents: Current status and implications for water safety assessment

Antineoplastic compounds, designed for chemotherapeutic anticancer therapy, have become emerging contaminants of global concern over the past decade due to their ubiquitous occurrence, environmental persistence, and multiple adverse effects on aquatic ecosystems. Increasing efforts have been devoted to developing efficient strategies for remediating water containing these micropollutants. In this study, the physicochemical properties, natural attenuation, and chemical reactivity with aqueous oxidizing species of five antineoplastic drugs with the highest environmental prevalence (i.e., tamoxifen, cyclophosphamide, ifosfamide, 5-fluorouracil, and methotrexate) were summarized. The removal performance, transformation products (TPs) of varying structures, overall reaction pathways, and toxicity evolution during different treatments were evaluated and discussed. Additionally, the biodegradability and multi-endpoint toxicity of each TP were predicted using in silico QSAR software. Depending on their distinct inherent structures, the reactivity of the antineoplastics with oxidizing species varied, with hydroxyl radicals exhibiting unparalleled merits in rapid oxidation. Complete elimination of these contaminants was observed during oxidative treatments, but with inadequate mineralization. Notably, the increase in toxicity within multiple processes was determined based on both experimental bioassays and theoretical predictions. This may be attributed to the adverse effects induced by the large number of identified and unknown TPs individually and in combination. Together with the environmental persistence and low biodegradability of most TPs, these results necessitate the application of efficient post-treatments in conjunction with a more thorough water safety evaluation (e.g., using high-throughput screening) of the mixtures of treated water and wastewater.

The Dark Side of Platinum Based Cytostatic Drugs: From Detection to Removal

The uncontrolled release of pharmaceutical drugs into the environment raised serious concerns in the last decades as they can potentially exert adverse effects on living organisms even at the low concentrations at which they are typically found. Among them, platinum based cytostatic drugs (Pt CDs) are among the most used drugs in cancer treatments which are administered via intravenous infusion and released partially intact or as transformation products. In this review, the studies on environmental occurrence, transformation, potential ecotoxicity, and possible treatment for the removal of platinum cytostatic compounds are revised. The analysis of the literature highlighted the generally low total platinum concentration values (from a few tens of ng L−1 to a few hundred μg L−1) found in hospital effluents. Additionally, several studies highlighted how hospitals are sources of a minor fraction of the total Pt CDs found in the environment due to the slow excretion rate which is longer than the usual treatment durations. Only some data about the impact of the exposure to low levels of Pt CDs on the health of flora and fauna are present in literature. In some cases, adverse effects have been shown to occur in living organisms, even at low concentrations. Further ecotoxicity data are needed to support or exclude their chronic effects on the ecosystem. Finally, fundamental understanding is required on the platinum drugs removal by MBR, AOPs, technologies, and adsorption.

White-rot fungi-mediated biodegradation of cytostatic drugs - bleomycin and vincristine

The contamination of the environment with anticancer drugs, which show recalcitrance to conventional wastewater treatment, has become a significant ecological threat. Fungi represent a promising non-conventional biological alternative for water conditioning. The aim of this work was to evaluate the efficacy of five white-rot fungi (Fomes fomentarius (CB13), Hypholoma fasciculare (CB15), Phyllotopsis nidulans (CB14), Pleurotus ostreatus (BWPH) and Trametes versicolor (CB8)) in the removal of bleomycin and vincristine. The removal capacity was measured at 0, 4, 9, and 14 days of incubation using SPE-UPLC-MS. The enzymatic profiles of laccase, manganese, and lignin peroxidases and wide range of eco- and cytotoxicity, assays of the post-process samples were also conducted. We observed >94% vincristine elimination by F. fomentarius, H. fasciculare and T. versicolor after only 4 days. Bleomycin removal occurred after a minimum of 9 days and only when the drug was incubated with T. versicolor (36%) and H. fasciculare (25%). The removal of both cytostatics was associated with laccase production, and the loss of eco- and cytotoxicity, especially in regard to viability of Lemna minor and Daphnia magna, as well as fibroblasts morphology.

Insight into the Sorption of 5-Fluorouracil and Methotrexate onto Soil-pH, Ionic Strength, and Co-Contaminant Influence

Nowadays anticancer drugs (ADs), like other pharmaceuticals, are recognized as new emerging pollutants, meaning that they are not commonly monitored in the environment; however, they have great potential to enter the environment and cause adverse effects there. The current scientific literature highlights the problem of their presence in the aquatic environment by publishing more and more results on their analytics and ecotoxicological evaluation. In order to properly assess the risk associated with the presence of ADs in the environment, it is also necessary to investigate the processes that are important in understanding the environmental fate of these compounds. However, the state of knowledge on mobility of ADs in the environment is still very limited. Therefore, the main aim of our study was to investigate the sorption potential of two anticancer drugs, 5-fluorouracil (5-FU) and methotrexate (MTX), onto different soils. Special attention was paid to the determination of the influence of pH and ionic strength as well as presence of co-contaminants (cadmium (Cd²⁺) and another pharmaceutical-metoprolol (MET)) on the sorption of 5-FU and MTX onto soil. The obtained distribution coefficient values (K_d) ranged from 2.52 to 6.36 L·kg^-1 and from 6.79 to 12.94 L·kg^-1 for 5-FU and MTX, respectively. Investigated compounds may be classified as slightly or low mobile in the soil matrix (depending on soil). 5-FU may be recognized as more mobile in comparison to MET. It was proved that presence of other soil contaminants may strongly influence their mobility in soil structures. The investigated co-contaminant (MET) caused around 25-fold increased sorption of 5-FU, whereas diminished sorption of MTX. Moreover, the influence of environmental conditions such as pH and ionic strength on their sorption has been clearly demonstrated.

Elucidation of S-Allylcysteine Role in Inducing Apoptosis by Inhibiting PD-L1 Expression in Human Lung Cancer Cells

AIM

The aim of this study is to explore the therapeutic potential of S-allylcysteine (SAC) organosulphur compound as a potent immune checkpoint inhibitor PD-L1.

BACKGROUND

Natural compounds have been showing tremendous anticancerous potential via suppressing the expression of genes involved in the development and progression of several carcinomas. This has further motivated us to explore the therapeutic potential of organosulphur compounds as potent immune checkpoint inhibitors.

OBJECTIVE

Our study was designed to elucidate the potential of S-allylcysteine (SAC) as significant PD-L1 (immune checkpoint) inhibitor in human lung cancer A549 cancer cell line by using both the in vitro and in silico approaches.

METHODS

Anticancerous effect of the SAC on lung cancer cells was determined by using the MTT cell viability. Apoptotic induction was confirmed by Hoechst staining, percent caspase-3 activity as well as gene expression analysis by real time PCR. Reactive Oxygen Species (ROS) was estimated by DCFDA method. Additionally, ligand-target protein interaction was analysed by molecular docking.

RESULT

Cell growth and proliferation was significantly reduced in SAC treated A549 cells in a concentration and time.dependent manner. The effect of SAC on apoptotic induction was analyzed by enhanced nuclear condensation, increased percent caspase-3 activity as well as modulation of apoptotic genes. Furthermore, SAC treatment also resulted in reduced expression of PD-L1 and HIF-1α. Additionally, in silico analysis also supported the in vitro findings by showing efficient docking with PD-L1 immune checkpoint target.

CONCLUSION

Therefore, our results clearly suggested that SAC could serve as a novel chemotherapeutic candidate for the treatment of lung cancer by inhibiting immune checkpoint target PD-L1 in human lung cancer cells. Additionally, our study also explained a novel molecular mechanism of its antitumor activity.

Cytotoxic responses of the anticancer drug cyclophosphamide in the mussel Mytilus galloprovincialis and comparative sensitivity with human cells lines

The rise of cancer cases worldwide led to an increase in production and consumption of anticancer drugs, that ultimately end up in the marine environment and are accumulated in aquatic organisms. Cyclophosphamide (CP) is a cytotoxic alkylating agent frequently prescribed in cancer treatments. This study assess ecotoxicological effects of CP on mussels Mytilus galloprovincialis, through in vivo and ex vivo approaches and compares the sensitivity of mussel haemocytes with well-established human cell lines (RPE and HeLa). Mussels were exposed in vivo to CP (1000 ng L^-1) and several biomarkers analysed in gills and digestive glands namely neurotoxicity (AChE activity), oxidative stress (GPx activity), biotransformation (GST activity), lipid peroxidation (LPO) and apoptosis (caspase activity), whereas genotoxicity was determined in mussels' haemocytes. Cytotoxicity was also assessed in haemocytes (in vivo and ex vivo) and human cell lines (in vitro) exposed to a range of CP concentrations (50, 100, 250, 500 and 1000 ng L^-1) over 24 h, via neutral red assay. In in vivo exposure, detoxification of CP did not efficiently occur in the gills while in digestive glands GPx and GST activities were induced, jointly with a decrease in lipid peroxidation, indicating a potential outcome of the protective antioxidant mechanisms, whereas no apoptosis was noted. Moreover, cytotoxicity and DNA damage were detected in haemocytes. The ex vivo exposure haemocytes to CP caused cytotoxicity (from 100 ng L^-1), whereas no effects occurred in human cell lines. This suggests that, at relevant environmental concentrations, CP cause subtle and irreversible impacts on M. galloprovincialis.

Organic micropollutants in water and sediment from Lake Mälaren, Sweden

The occurrence and distribution of 111 organic micropollutants (OMPs) were evaluated in water and sediment samples from Lake Mälaren, Sweden, using a liquid chromatography-tandem mass spectrometry method. The partitioning of contaminants between lake compartments was estimated using solid water distribution coefficients (K_d) and organic carbon-water partitioning coefficients (K_OC). In total, 30 and 24 OMPs were detected in lake water and sediment, respectively. Concentrations ranged from low ng/L to 89 ng/L (lamotrigine) in lake water and from low ng/g dry weight (dw) to 28 ng/g dw (citalopram) in sediment. Carbamazepine, lamotrigine, caffeine, and tolyltriazole were the dominant compounds in Lake Mälaren samples (both water and sediment). Seventeen OMPs were detected in both water and sediment samples, including carbamazepine, DEET, tolyltriazole, bicalutamide, caffeine, lamotrigine, and cetirizine. Log K_d values varied between 0.84 for lamotrigine and 4.4 for citalopram, while log K_OC values varied between 2.1 for lamotrigine and 5.9 for citalopram. These results indicate that sorption to sediment plays a minor role in removal of all OMPs analyzed in the aqueous phase except for citalopram and cetirizine, which showed high sorption potential. The environmental risks of OMPs were assessed based on the RQ values. The worst-case scenario for environmental risk assessment was conducted using the maximum measured environment concentration. For most of the target OMPs, including tolyltriazole, bicalutamide, fexofenadine, oxazepam, cetirizine, and diclofenac, the RQ values were below 0.01, indicating low or no risk to lake ecosystems.

Fate and toxicity of pharmaceuticals in water environment: An insight on their occurrence in South Asia

Pharmaceutically active compounds are newly recognized micropollutants which are ubiquitous in aquatic environment mainly due to direct discharge of treated and untreated wastewater from wastewater treatment plants. These contaminants have attracted mounted attention due to their toxic effects on aquatic life. They disrupt biological processes in non-target lower organisms upon exposure. Biodegradation, photo-degradation, and sorption are key processes which determine their fate in the environment. A variety of conventional and advanced treatment processes had been extensively investigated for the removal of pharmaceuticals from wastewater. However, due to structural complexity and varying operating parameters, complete removal seems ideal. Generally, due to high energy requirement of advanced treatment technology, it is considered cost ineffective. Transport of pharmaceutical compounds occurs via aquatic channels whereas sediments and aquatic colloids play a significant role as sinks for these contaminants. The current review provides a critical understanding of fate and toxicity of pharmaceutical compounds and highlights their vulnerability and occurrence in South Asia. Antibiotics, analgesics, and psychiatric drugs were found predominantly in the water environment of South Asian regions. Despite significant advances in understanding pharmaceuticals fate, toxicity, and associated risks since the 1990s, still substantial data gaps in terms of monitoring, human health risks, and legislation exist which presses the need to develop a more in-depth and interdisciplinary understanding of the subject.

Environmental Remediation of Antineoplastic Drugs: Present Status, Challenges, and Future Directions

The global burden of cancer is on the rise, and as a result, the number of therapeutics administered for chemotherapy is increasing. The occupational exposure, recalcitrant nature and ecotoxicological toxicity of these therapeutics, referred to as antineoplastic (ANP) drugs, have raised concerns about their safe remediation. This review provides an overview of the environmental source of ANPs agents, with emphasis on the currently used remediation approaches. Outpatient excreta, hospital effluents, and waste from pharmaceutical industries are the primary source of ANP waste. The current review describes various biotic and abiotic methods used in the remediation of ANP drugs in the environment. Abiotic methods often generate transformation products (TPs) of unknown toxicity. In this light, obtaining data on the environmental toxicity of ANPs and its TPs is crucial to determine their toxic effect on the ecosystem. We also discuss the biodegradation of ANP drugs using monoculture of fungal and bacterial species, and microbial consortia in sewage treatment plants. The current review effort further explores a safe and sustainable approach for ANP waste treatment to replace existing chemical and oxidation intensive treatment approaches. To conclude, we assess the possibility of integrating biotic and abiotic methods of ANP drug degradation.

Monitoring hospital wastewaters for their probable genotoxicity

Hospitals' effluents contain a considerable amount of chemicals. Considering the significant volume of wastewater discharged by hospitals, the presence of these chemicals represents a real threat to the environment and human health. Thus, the aim of this study was to evaluate the in vivo and in vitro genotoxicities of three wastewater effluents collected from Tunisian hospitals. The liver of Swiss albino male mice, previously treated with different doses of the hospital wastewaters, was used as a model to detect DNA fragmentation. Our results showed all the hospital effluents caused significant qualitative and quantitative hazards in hepatic DNA. The wastewater collected from Sfax hospital exhibited the highest genotoxic effect, which may be explained by the presence in this effluent of some toxic micropolluants. There was a significant increase in genotoxicity, proportionally to the concentration of effluent. However, the vitotox assay did not show any significant genotoxicity on Salmonella typhimurium TA104 in the presence or absence of microsomal fraction S9. The ratio gentox/cytox was lower than the threshold 1.5. This study assessed the toxicological risk issued from Tunisian hospital wastewaters, which is potentially very harmful, and it has been pointed out that wastewater treatment requires special attention.

Considerations for the Use of Mutation as a Regulatory Endpoint in Risk Assessment

Assessment of a chemical's potential to cause permanent changes in the genetic code has been a common practice in the industry and regulatory settings for decades. Furthermore, the genetic toxicity battery of tests has typically been employed during the earliest stages of the research and development programs of new product development. A positive outcome from such battery has a major impact on the chemical's utility, industrial hygiene, product stewardship practices, and product life cycle analysis, among many other decisions that need to be taken by the industry, even before the registration of a chemical is undertaken. Under the prevailing regulatory paradigm, the dichotomous (yes/no) evaluation of the chemical's genotoxic potential leads to a conservative, linear no-threshold (LNT) risk assessment, unless compelling and undeniable data to the contrary can be provided to satisfy regulators, typically in a number of different global jurisdictions. With the current advent of predictive methods, new testing paradigms, mode-of-action/adverse outcome pathways, and quantitative risk assessment approaches, various stakeholders are starting to employ these state-of-the-science methodologies to further the conversation on decision making and advance the regulatory paradigm beyond the dominant LNT status quo. This commentary describes these novel methodologies, relevant biological responses, and how these can affect internal and regulatory risk assessment approaches. Environ. Mol. Mutagen. 61:84-93, 2020. © 2019 Wiley Periodicals, Inc.

Environmental risk assessment of widely used anticancer drugs (5-fluorouracil, cisplatin, etoposide, imatinib mesylate)

Anticancer drugs are among the most toxic chemicals, which are commercially produced; therefore, their release in aquatic ecosystems raised concerns in regard to potential adverse effects. This article describes the results of risk assessments concerning their environmental safety, which are based on data generated in the frame of a coordinated EU project ("Cytothreat"). Eight research institutions participated in the project and four widely used anticancer drugs with different mechanisms of therapeutic action (5-fluorouracil 5FU, cisplatin CDDP, imatinib mesylate IM and etoposide ET) were tested in a variety of indicator organisms (cyanobacteria, algae, higher plants, rotifers, crustacea, fish and also in human and fish derived cell lines) in acute/subacute/chronic toxicity assays. Furthermore, genotoxic effects in micronucleus assays, single cell gel electrophoresis experiments and γH2AX tests were studied in plants, crustacea, fish and in various cell lines. We used the results to calculate the predicted no effect concentrations (PNEC) and risk quotients (RQ) by comparing PNEC with predicted environmental concentrations (PEC values) and measured concentrations (MEC) in wastewaters. The most sensitive species in experiments concerning acute toxic and long term effects were in general crustacea (daphnids) after chronic treatment the most pronounced effects were detected with IM followed by CDDP and 5FU. Comparisons between PNEC and PEC values indicate that it is unlikely that the release of these drugs in the aquatic environments leads to adverse effects (RQ values < 1). However, when the assessments were performed with MEC found in highly contaminated municipal wastewaters and hospital effluents, RQ values were obtained which are indicative for moderate adverse effects of IM. Calculations with data from genotoxicity experiments and PEC values are indicative for increased RQ values for all compounds except ET. The most sensitive species were fish (Danio rerio) which were highly responsive towards 5FU and daphnids which were sensitive towards CDDP and IM. When environmental data (from waste waters) were used for the calculations, high RQ values (>100) were obtained for CDDP and IM. These overall conclusions were not substantially altered when the effects of other frequently used cytostatic drugs and combined effects of mixtures of anticancer drugs were taken into consideration. The results of these assessments underline the importance of efficient removal of these chemicals by improved sewage treatment strategies and the need for further investigations of adverse the long term effects of cytostatics in aquatic biota as a consequence of damage of the genetic material in highly sensitive species.

5-Fluorouracil-Complete Insight into Its Neutral and Ionised Forms

5-Fluorouracil (5FU), a common anti-cancer drug, occurs in four tautomeric forms and possesses two potential sites of both protonation and deprotonation. Tautomeric and resonance structures of the ionized forms of 5FU create the systems of connected equilibriums. Since there are contradictory reports on the ionized forms of 5FU in the literature, complex theoretical studies on neutral, protonated and deprotonated forms of 5FU, based on the broad spectrum of DFT methods, are presented. These indicate that the O4 oxygen is more willingly protonated than the O2 oxygen and the N1 nitrogen is more willingly deprotonated than the N3 nitrogen in a gas phase. Such preferences are due to advantageous charge delocalization of the respective ions, which is demonstrated by the NBO and ESP analyses. In an aqueous phase, stability differences between respective protonated and deprotonated forms of 5FU are significantly diminished due to the competition between the mesomeric effect and solvation. The calculated pK_a values of the protonated, neutral and singly deprotonated 5FU indicate that 5FU does not exist in the protonated and double-deprotonated forms in the pH range of 0–14. The neutral form dominates below pH 8 and the N1 deprotonated form dominates above pH 8.

Effects of mixtures of anticancer drugs in the benthic polychaete Nereis diversicolor

The increasing consumption of anticancer drugs through single and/or combinatory chemotherapy worldwide raised concern regarding their toxicity burden in coastal zones. The toxicity of a mixture of three compounds involving the drugs cisplatin (CisPt), cyclophosphamide (CP) and tamoxifen (TAM) was determined on the marine polychaete Nereis diversicolor exposed to an increasing range of their concentrations, respectively: Mix A: 0.1 + 10 + 0.1 ng L^-1; Mix B: 10 + 100 + 10 ng L^-1; Mix C: 100 + 500 + 25 ng L^-1; Mix D: 100 + 1000 + 100 ng L^-1. Different endpoints were assessed, including disturbance in the burrowing behaviour, neurotoxicity (acetylcholinesterase - AChE activity), antioxidant enzymes (superoxide dismutase - SOD; catalase - CAT; selenium-dependent glutathione peroxidase - Se-GPx and total glutathione peroxidases T-GPx activities), biotransformation metabolism (glutathione-S-transferases - GST), lipid peroxidation (LPO) and genotoxicity (DNA damage). Biological effects of the mixtures of anticancer compounds on N. diversicolor were compared with previous studies about effects on the same biological model under single-drug exposure conducted with the same molecules. Regarding SOD activity, TAM showed an antagonist effect over CisPt and CP in mixtures C and D. In Mix D, there was a synergistic effect of TAM and CisPt that inhibited CAT activity and an additive interaction of CisPt and CP on the Phase II biotransformation enzyme. Drugs in Mix A also suppressed polychaetes' GST activity, although different from the respective single-drug responses, besides able to induce T-GPx activity, that was not sufficient to avoid oxidative damage and mid-grade DNA damage. Due to the absence of burrowing impairment in Mix A, mechanisms involved in neurotoxicity were other than the one driven by AChE alterations. At the intermediary concentrations (Mix B and C), only LPO occurred. Data from drugs individually may not predict the risks provided by mixtures.

Cumulative effects of municipal effluent and parasite infection in yellow perch: A field study using high-throughput RNA-sequencing

Multiple metabolic, immune and reproductive effects have been reported in fish residing in effluent-impacted sites. Natural stressors such as parasites also have been shown to impact the responses of organisms to chronic exposure to municipal effluent in the St. Lawrence River (Quebec, Canada). In order to comprehensively evaluate the cumulative impacts of anthropogenic and natural stressors on the health of yellow perch, differential mRNA transcription profiles were examined in juvenile females collected from effluent-impacted and upstream sites with low or high infection levels of the larval trematode Apophallus brevis. Transcriptomics was used to identify biological pathways associated with environmental exposure. In total, 3463 isoforms were differentially transcribed between sites. Patterns reflecting the combined effects of stressors were numerically dominant, with a majority of downregulated transcripts (68%). The differentially expressed transcripts were associated with 27 molecular and cellular functions ranging from cellular development to xenobiotic metabolism and were involved in the development and function of 13 organ systems including hematological, hepatic, nervous, reproductive and endocrine systems. Based on RNA-seq results, sixteen genes were measured by qPCR. Significant differences were observed for six genes in fish exposed to both stressors combined, whereas parasites and effluent individually impacted the transcription of one gene. Lysozyme activity, lipid peroxidation, retinol-binding protein and glucose-6-phosphate dehydrogenase were selected as potential biomarkers of effects to study specific pathways of interest. Lipid peroxidation in perch liver was different between sites, parasite loads, and for combined stressors. Overall, results indicated that juvenile yellow perch responded strongly to combined parasite and effluent exposure, suggesting cumulative effects on immune responses, inflammation and lipid metabolism mediated by retinoid receptors. The present study highlight the importance of using a comprehensive approach combining transcriptomics and endpoints measured at higher levels of biological organization to better understand cumulative risks of contaminants and pathogens in aquatic ecosystems.

Ecotoxicity risk of presence of two cytostatic drugs: Bleomycin and vincristine and their binary mixture in aquatic environment

Cytostatic drugs have become one of the greatest environmental threats. They occur in surface, ground and even drinking water. Their key emission sources are hospital effluents, municipal wastewater, as well as drug manufacturers and their effluents. These compounds are extremely stable in natural waters and they are not significantly removed during wastewater treatment, because they are resistant to biodegradation. The aim of this work was to establish possible negative effects of chosen cytostatics: bleomycin and vincristine on the three trophic levels of surface waters. A single agent acute toxicity test was conducted on representatives of the producer - an aquatic freshwater plant Lemna minor, the consumer - crustaceans Daphnia magna, and the decomposer - bacteria Pseudomonas putida. Binary mixture tests were performed according to the Concentration Addition, Response Additivity, and Independent Action models. Both substances had a different effect on the tested organisms; bleomycin could be classified as a very toxic, while vincristine as a toxic water pollutant. Half maximal effective concentration (EC50) values designed in the presented single agent acute toxicity studies are < 10 mg/L in all the tests with bleomycin as well as vincristine conducted on L. minor. In tests with vincristine performed on D. magna and P. putida EC50 > 100 mg/L. The highest toxicity is demonstrated by bleomycin towards the aquatic freshwater plant (EC50 = 0.2 mg/L). The binary mixture of the tested chemicals showed antagonistic effects of environmental concern.

Imatinib: Major photocatalytic degradation pathways in aqueous media and the relative toxicity of its transformation products

Imatinib (IMA) is a highly potent tyrosine kinase inhibitor used as first-line anti-cancer drug in the treatment of chronic myeloid leukemia. Due to its universal mechanism of action, IMA also has endocrine and mutagenic disrupting effects in vivo and in vitro, which raises the question of its environmental impact. However, to date, very little information is available on its environmental fate and the potential role of its transformation products (TPs) on aquatic organisms. Given the IMA resistance to hydrolysis and direct photolysis according to the literature, we sought to generate TPs through oxidative and radical conditions using the AOPs pathway. Thus, the reactivity of the cytotoxic drug IMA in water in the presence of OH and h+ was investigated for the first time in the present work. In this regard, a non-targeted screening approach was applied in order to reveal its potential TPs. The tentative structural elucidation of the detected TPs was performed by LC-HRMSⁿ. The proposed approach allowed detecting a total of twelve TPs, among which eleven are being described for the first time in this work. Although the structures of these TPs could not be positively confirmed due to lack of standards, their chemical formulas and product ions can be added to databases, which will allow their screening in future monitoring studies. Using the quantitative structure-activity relationship (QSAR) approach and rule-based software, we have shown that the detected TPs possess, like their parent molecule, comparable acute toxicity as well as mutagenic and estrogenic potential. In addition to the in silico studies, we also found that the samples obtained at different exposure times to oxidative conditions, including those where IMA is no longer detected, retained toxicity in vitro. Such results suggest further studies are needed to increase our knowledge of the impact of imatinib on the environment.

A comparative study on the photo-catalytic degradation of Cytarabine anticancer drug under Fe3+/H2O2, Fe3+/S2O82-, and [Fe(C2O4)3]3-/H2O2 processes. Kinetics, identification, and in silico toxicity assessment of generated transformation products

Cytarabine (CY) is an anticancer drug which has been identified in wastewater influents, effluents, and surface waters. In the present study, the degradation of CY under simulated solar light (SSL), by photo-Fenton (Fe³⁺/H₂O₂/SSL) and photo-Fenton-like processes (Fe³⁺/S₂O₈^2-/SSL and [Fe(C₂O₄)₃]^3-/H₂O₂/SSL), was investigated. The major parameters affecting the applied treatments (e.g., concentration of CY, Fe³⁺, H₂O₂, and S₂O₈^2-) were optimized and CY's complete removal was achieved within 45 min for all techniques used. Mineralization studies indicated that [Fe(C₂O₄)₃]^3-/H₂O₂/SSL treatment was the most efficient procedure since faster kinetics are achieved and higher mineralization percentage is reached compared to the other techniques used. Furthermore, 12 transformation products (TPs) were identified during the applied processes, by high resolution mass spectrometry, four of which were identified for the first time, indicating that CY molecule undergoes hydroxylation and subsequent oxidation, during the applied processes. Moreover, predictions of acute and chronic ecotoxicity of CY and its TPs on fish, daphnia, and green algae were conducted, using in silico quantitative structure activity relationship (QSAR) calculations. According to these predictions, the TPs generated during the studied treatments may pose a threat to aquatic environment. Finally, the efficiency of CY degradation by photo-Fenton and photo-Fenton-like treatment in real wastewater was evaluated, under the optimized conditions, which resulted in lower degradation rate constants compared to ultrapure water.

Reducing aquatic micropollutants - Increasing the focus on input prevention and integrated emission management

Pharmaceuticals and many other chemicals are an important basis for nearly all sectors including for example, food and agriculture, medicine, plastics, electronics, transport, communication, and many other products used nowadays. This comes along with a tremendous chemicalization of the globe, including ubiquitous presence of products of chemical and pharmaceutical industries in the aquatic environment. Use of these products will increase with population growth and living standard as will the need for clean water. In addition, climate change will exacerbate availability of water in sufficient quantity and quality. Since its implementation, conventional wastewater treatment has increasingly contributed to environmental protection and health of humans. However, with the increasing pollution of water by chemicals, conventional treatment turned out to be insufficient. It was also found that advanced effluent treatment methods such as extended filtration, the sorption to activated charcoal or advanced oxidation methods have their own limitations. These are, for example, increased demand for energy and hazardous chemicals, incomplete or even no removal of pollutants, the generation of unwanted products from parent compounds (transformation products, TPs) of often-unknown chemical structure, fate and toxicity. In many countries, effluent treatment is available only rarely if at all let alone advanced treatment. The past should teach us, that focusing only on technological approaches is not constructive for a sustainable water quality control. Therefore, in addition to conventional and advanced treatment optimization more emphasis on input prevention is urgently needed, including more and better control of what is present in the source water. Measures for input prevention are known for long. The main focus though has always been on the treatment, and measures taken at the source have gained only little attention so far. A more effective and efficient approach, however, would be to avoid pollution at the source, which would in turn allow more targeted treatment to meet treated water quality objectives globally. New developments within green and sustainable chemistry are offering new approaches that allow for input prevention and a more targeted treatment to succeed in pollution elimination in and at the source. To put this into practice, engineers, water scientists and chemists as well as microbiologists and scientists of other related disciplines need to cooperate more extensively than in the past. Applying principles such as the precautionary principle, or keeping water flows separate where possible will add to this. This implies not minimizing the efforts to improve wastewater treatment but to design effluents and chemicals in such a way that treatment systems and water environments can cope successfully with the challenge of micropollutants globally (Kümmerer et al., 2018). This paper therefore presents in its first part some of the limitations of effluent treatment in order to demonstrate the urgent need for minimizing water pollution at the source and, information on why source management is urgently needed to improve water quality and stimulate discussions how to protect water resources on a global level. Some principles of green and sustainable chemistry as well as other approaches, which are part of source management, are presented in the second part in order to stimulate discussion.

Do Amazon turtles exposed to environmental concentrations of the antineoplastic drug cyclophosphamide present mutagenic damages? If so, would such damages be reversible?

Antineoplastic drugs (AD) have been increasingly used, but the disposal of their wastes in the environment via hospital effluent and domestic sewage has emerged as an environmental issue. The current risks posed to these animals and effects of pollutants on the reptiles' population level remain unknown due to lack of studies on the topic. The aim of the present study was to evaluate the mutagenicity of neonate Podocnemis expansa exposed to environmental concentrations (EC) of cyclophosphamide (Cyc). The adopted doses were EC-I 0.2 μg/L and EC-II 0.5 μg/L Cyc. These doses correspond to 1/10 and ¼ of concentrations previously identified in hospital effluents. Turtles exposed to the CyC recorded larger total number of erythrocyte nuclear abnormalities than the ones in the control group after 48-h exposure. The total number of abnormalities for both groups (EC-I and EC-II) 96 h after the experiment had started was statistically similar to that of animals exposed to high Cyc concentration (positive control 5 × 10⁴ μg/L). This outcome confirms the mutagenic potential of Cyc, even at low concentrations. On the other hand, when the animals were taken to a pollutant-free environment, their mutagenic damages disappeared after 240 h. After such period, their total of abnormalities matched the basal levels recorded for the control group. Therefore, our study is the first evidence of AD mutagenicity in reptiles, even at EC and short-term exposure, as well as of turtles' recovery capability after the exposure to Cyc.

Cytostatic drug removal using electrochemical oxidation with BDD electrode: Degradation pathway and toxicity

In the presented study, electrochemical oxidation of five anticancer drugs (5-fluorouracil (5-FU), ifosfamide (IF), cyclophosphamide (CF), methotrexate (MTX), imatinib (IMB)) using boron doped diamond (BDD) electrode was investigated. In the first step the operating parameters of electrolysis were optimized. Studies have demonstrated a significant influence of applying current density, temperature, pH of solution and initial concentration of 5-FU on the process efficiency. A comparison of the decomposition rate of all the tested drugs showed a decrease in the pseudo-first order rate constants in the following order: k(IMB) > k(MTX) > k(CF) ≈ k(IF) > k(5-FU). Mineralization current efficiency (MCE) was determined for all the drugs based on the removal amount of total organic carbon (TOC) and their values decreased in the same order as values of drug degradation rate k. Based on the identified degradation products, electrochemical oxidation pathways of the decomposed drugs were proposed. In the case of CF, IF and 5-FU the degradation process occurred mainly through ketonization, hydroxylation and dehalogenation, while MTX and IMB were decomposed by attack of hydroxyl radicals on benzyl position in parent compounds. An important part of the research was the evaluation of eco-toxicity of electrochemically treated drug solutions against Lemna minor. Toxicity of initial 5-FU and MTX solutions towards L. minor were observed but after electrochemical treatment its toxicity decreased. The opposite trend was observed for CF and IF. In this case no significant toxicity was observed for the initial solutions of these drugs, while after electrochemical treatment an increase in growth inhibition of L. minor was found.

Distribution of Anticancer Drugs in River Waters and Sediments of the Yodo River Basin, Japan

This article reviews the pollution status of anticancer drugs present in the Yodo River basin located in the Kansai district of Japan, covering both the soluble and insoluble (adsorbed on the river sediments and suspended solids) levels. Procedures ranging from sampling in the field and instrumental analytical methods to the data processing for mass balance estimation of the target basin are also described. All anticancer drugs concerned with this article were detected in sewage and river waters, where the presence of bicalutamide (BLT) was identified at considerably high concentrations (maximum 254 ng/L in the main stream, 151 ng/L in tributaries, and 1032 ng/L in sewage treatment plant (STP) effluents). In addition, sorption distribution coefficient (logKd) values showed a tendency to become higher in the silty sediments at Suita Bridge than in the sandy sediments at Hirakata Bridge; these trends were supported by the results of the laboratory-scale sorption experiment. STPs were concluded to be the main sources of the anticancer drug load in the river, and a mass flux evaluation revealed that the effect of attenuation in the river environment was small. The effectiveness of ozonation in the sewage treatment process for removal of these anticancer drugs was further confirmed. The present article should be of value for facilitating the environmental risk assessment of a wide range of drugs in a broader geographical area.

Occupational exposure to cytotoxic drugs: the importance of surface cleaning to prevent or minimise exposure

Healthcare workers who prepare or administer cytotoxic agents run the risk of exposure, and the risks for health are real even at doses lower than those applied in cancer patients, because, in theory, no dose is safe. The most common and problematic route of exposure is through the skin, especially as work surfaces can remain contaminated even after cleaning. This pilot study aimed to demonstrate the importance of having an effective surface decontamination protocol by determining surface contamination with cyclophosphamide, 5-fluorouracil, and paclitaxel as the most common cytotoxic drugs in an oncology day service. Samples were collected before and after drug handling and analysed with high performance liquid chromatography with diode array detection (HPLC-DAD). Of the 29 samples collected before drug handling 23 were contaminated, five of which with more than one drug. Of the 30 samples collected after drug handling 25 were contaminated, eight of which with more than one drug. The two time points did not significantly differ, which evidences a widespread contamination and ineffective cleaning. This calls for revising the cleaning protocol and handling procedure to place contamination under control as much as possible.

Toxicogenomic responses of low level anticancer drug exposures in Daphnia magna

The use of anticancer drugs in chemotherapy is increasing, leading to growing environmental concentrations of imatinib mesylate (IMA), cisplatinum (CDDP), and etoposide (ETP) in aquatic systems. Previous studies have shown that these anticancer drugs cause DNA damage in the crustacean Daphnia magna at low, environmentally relevant concentrations. To explore the mechanism of action of these compounds and the downstream effects of DNA damage on D. magna growth and development at a sensitive life stage, we exposed neonates to low level concentrations equivalent to those that elicit DNA damage (IMA: 2000 ng/L, ETP: 300 ng/L, CDDP: 10 ng/L) and performed transcriptomic analysis using an RNA-seq approach. RNA sequencing generated 14 million reads per sample, which were aligned to the D. magna genome and assembled, producing approximately 23,000 transcripts per sample. Over 90% of the transcripts showed homology to proteins in GenBank, revealing a high quality transcriptome assembly, although functional annotation was much lower. RT-qPCR was used to identify robust biomarkers and confirmed the downregulation of an angiotensin converting enzyme-like gene (ance) involved in neuropeptide regulation across all three anticancer drugs and the down-regulation of DNA topoisomerase II by ETP. RNA-seq analysis also allowed for an in depth exploration of the differential splicing of transcripts revealing that regulation of different gene isoforms predicts potential impacts on translation and protein expression, providing a more meaningful assessment of transcriptomic data. Enrichment analysis and investigation of affected biological processes suggested that the DNA damage caused by ETP and IMA influences cell cycle regulation and GPCR signaling. This dysregulation is likely responsible for effects to neurological system processes and development, and overall growth and development. Our transcriptomic approach provided insight into the mechanisms that respond to DNA damage caused by anticancer drug exposure and generated novel hypotheses on how these chemicals may impact the growth and survival of this ecologically important zooplankton species.

Evaluation of genotoxic potential of tert-butylquinone and its derivatives in prokaryotic and eukaryotic test models

Tert-butylquinone (TBQ) and its alkylamino and aralkylamino derivatives are of high interest as a potential antitumor agent. Therefore, it was necessary to investigate if the compounds exert undesirable activities such as interaction with DNA molecule which could result in negative side effects in the case of their use in the diseases treatment. The major aim of this study was to investigate genotoxic potential of TBQ and selected derivatives in an acellular model by using plasmid DNA, in the prokaryotic model by the SOS/umuC assay in Salmonella typhimurium TA1535/pSK1002 and in eukaryotic models by using comet assay in human fetal lung cell line (MRC-5) and human liver cancer cell line (HepG2). Results indicated that in the acellular model TBQ and its derivatives do not interact with plasmid pUC19. In the prokaryotic model, only TBQ exerted weak genotoxic potential and only at highly cytotoxic concentrations. In eukaryotic models, genotoxic potential was detected mainly at the highest concentrations of the tested substances but the effect was lower in both cell lines in comparison with benzo[a]pyrene and etoposide which were used as positive controls. Weak genotoxic potential of tested compounds recommends them as good candidates for further testing in development of new antitumor agents.

Ecotoxicity of disinfectant benzalkonium chloride and its mixture with antineoplastic drug 5-fluorouracil towards alga Pseudokirchneriella subcapitata

Background

Benzalkonium chloride (BAC) is one of the most common ingredients of the disinfectants. It is commonly detected in surface and wastewaters where it can interact with the residues of pharmaceuticals that are also common wastewater pollutants. Among the latter, the residues of antineoplastic drugs are of particular concern as recent studies showed that they can induce adverse effect in aquatic organisms at environmentally relevant concentrations.

Methods

Ecotoxicity of BAC as an individual compound and in a binary mixture with an antineoplastic drug 5-fluorouracil (5-FU) was determined towards alga Pseudokirchneriella subcapitata, a representative of primary producers. The toxicity of the BAC+5-FU binary mixture was predicted by the two basic models: concentration addition (CA) and independent action (IA), and compared to the experimentally determined toxicity. Additionally combination index (CI) was calculated to determine the type of interaction.

Results

After 72 h exposure to BAC a concentration dependent growth inhibition of P. subcapitata was observed with an EC₅₀ 0.255 mg/L. Comparing the predicted no effect concentration to the measured concentrations in the surface waters indicate that BAC at current applications and occurrence in aquatic environment may affect algal populations. The measured toxicity of the mixture was higher from the predicted and calculated CI confirmed synergistic effect on the inhibition of algal growth, at least at EC₅₀ concentration. The observed synergism may have impact on the overall toxicity of wastewaters, whereas it is less likely for general environments because the concentrations of 5-FU are several orders of magnitude lower from its predicted no effect concentration.

Discussion

These results indicate that combined effects of mixtures of disinfectants and antineoplastic drugs should be considered in particular when dealing with environmental risk assessment as well as the management of municipal and hospital wastewaters.

Genotoxicity assessment of a selected cytostatic drug mixture in human lymphocytes: A study based on concentrations relevant for occupational exposure

Cytostatic drugs are highly cytotoxic agents used in cancer treatment and although their benefit is unquestionable, they have been recognized as hazardous to healthcare professionals in occupational settings. In a working environment, simultaneous exposure to cytostatics may occur creating a higher risk than that of a single substance. Hence, the present study evaluated the combined cyto/genotoxicity of a mixture of selected cytostatics with different mechanisms of action (MoA; 5-fluorouracil, cyclophosphamide and paclitaxel) towards human lymphocytes in vitro at a concentration range relevant for occupational as well as environmental exposure. The results suggest that the selected cytostatic drug mixture is potentially cyto/genotoxic and that it can induce cell and genome damage even at low concentrations. This indicates not only that such mixture may pose a risk to cell and genome integrity, but also that single compound toxicity data are not sufficient for the prediction of toxicity in a complex working environment. The presence of drugs in different amounts and with different MoA suggests the need to study the relationship between the presence of genotoxic components in the mixture and the resulting effects, taking into account the MoA of each component by itself. Therefore, this study provides new data sets necessary for scientifically-based risk assessments of cytostatic drug mixtures in occupational as well as environmental settings.

In vitro and in vivo antitumor potential of carvacrol nanoemulsion against human lung adenocarcinoma A549 cells via mitochondrial mediated apoptosis

Carvacrol is present abundantly in the essential oils of many medicinal plants and well known for its numerous biological activities. Since partial solubility in water and physicochemical instability limits its industrial uses, the present study was performed to prepare a carvacrol nanoemulsion (CANE) using an ultrasonication technique and further evaluation of its anticancer potential against human lung adenocarcinoma A549 cells. The nanoemulsion formulation was optimized by varying carvacrol and polysorbate 80 ratios and characterized by dynamic light scattering (DLS), which revealed a negative surface charge with a mean droplet size between 105.5 ± 3.4 to 169.8 ± 4.9 nm. The CANE induced reactive oxygen species (ROS) production in A549 cells, leading to activation of key regulators of apoptosis such as p-JNK, Bax and Bcl2 as well as release of cytochrome C, and activation of the caspase cascade. Suppression of mitochondrial ROS using Mito-TEMPO reversed the apoptotic potential of CANE signifying involvement of mitochondrial ROS in cell death. Beside, CANE displayed a strong antitumor potential in vivo using an athymic nude mice model. The results strongly support that CANE induced apoptosis in A549 cells by induction of ROS and could be a promising candidate for lung cancer therapy.

A case study to identify priority cytostatic contaminants in hospital effluents

This study analyses the presence of 17 cytostatic agents from seven different groups, based on their different mechanisms of action, in the effluent from a medium-sized hospital located in eastern Spain. Analysis of the compounds found in the effluents studied involved solidphase extraction (SPE) coupled on-line to a high performance liquid chromatograph tandem mass spectrometer (HPLC-MS/MS). The environmental risk of the compounds studied was then assessed by calculating the hazard quotient (HQ), combining the measured environmental concentrations (MECs) with dose-response data based on the predicted no effect concentrations (PNECs). In addition, the environmental hazard associated was evaluated in accordance with their intrinsic characteristics by calculating the PBT (Persistence Bioaccumulation Toxicity) index. The results of this study showed the presence of seven of the 17 compounds analysed in a range of between 25 and 4761 ng/L. The highest concentrations corresponded to ifosfamide (58-4761 ng/L), methotrexate (394-4756 ng/L) and cyclophosphamide (46-3000 ng/L). Assessment of the environmental hazard showed that the three hormonal agents (tamoxifen and its metabolites endoxifen and hydroxytamoxifen) exhibited a maximum PBT value of 9 due to their inherent harm to the environment resulting from their characteristics of persistence, bioaccumulation and toxicity. A combined evaluation of the risk and environmental hazard showed that three of the 17 compounds studied, namely, ifosfamide, imatinib and irinotecan, all of which exhibited HQ values higher than 10 and PBT indices of 6, indicative of a particularly high potential to harm the environment, deserve special attention.

Suspect screening of micropollutants and their transformation products in advanced wastewater treatment

Transformation products (TPs) of organic micropollutants are still rarely considered in monitoring of wastewater and aquatic environments. For example, occurrence data of ozonated TPs in full-scale wastewater systems is largely lacking. In this study, the efficiency of a suspect screening strategy including 245 previously reported compounds and their TPs was evaluated for assessing the occurrence of different compound classes and their ozonated TPs in wastewater samples collected at different steps of an advanced treatment process including ozonation. After applying blank subtraction and filtering by mass accuracy (5ppm tolerance), peak height (minimum 1000 counts) and isotopic pattern score (≥80%) 189 of the 245 compounds were detected. A decrease in relative concentration levels was observed for parent compounds in wastewater after ozonation and after a subsequent biological treatment process, while formation of tentative TPs after ozonation accompanied by subsequent degradation in a following biological treatment step was found. Plausibility of structural assignments for tentatively identified TPs could be successfully tested by using relative retention time information as comparison criteria. Overall, the screening approach was fast and successful and can be expanded to other compound classes and TPs where reference standards are not readily available.