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

Trace cisplatin adsorption by thiol-functionalized sponge (TFS) and Sn/SnO2-coated TFS: Adsorption study and mechanism investigation

To remove trace cisplatin from aqueous solution, commercial sponges were functionalized by esterification with 3-mercaptopropionic acid, followed by reduction with Na2S·9H2O or SnCl2·2H2O. The resulting thiol-functionalized sponges (TFSs), TFS_1 and TFS_2, were tested for the removal of cisplatin (235 μg L-1) achieving maximum removal of 95.5 ± 0.8% and 99.5 ± 0.1% respectively, which were significantly higher than the non-functionalized counterpart. The successful grafting of thiol groups, verified through FTIR, elemental analysis, SEM-EDS, and XPS characterization, facilitated Pt-S complexation during adsorption. The aqua-derivatives of cisplatin, formed through hydration, complexed with thiol sites through ligand displacement. Additionally, the presence of Sn/SnO2 coating on TFS_2 further enhanced the adsorption process. The rapid adsorption process conformed to pseudo-second-order kinetic model, involving both diffusion and chemisorption. While the Langmuir isotherm model generally described the monolayer adsorption behavior of cisplatin, the aggregation of Sn/SnO2 onto TFS_2 at 343 K introduced surface heterogeneity, rendering the Freundlich model a better fit for the adsorption isotherm. Differential pH dependence and the evaluation of mean free energy, derived from the Dubinin-Radushkevich isotherm model, indicated that cisplatin adsorption onto TFS_1 involved physisorption, including electrostatic attraction, while chemisorption predominated for TFS_2. Increasing the temperature notably promoted adsorption by facilitating the thermal-favored formation of Pt-S bonds.

Activity in Group-Housed Home Cages of Mice as a Novel Preclinical Biomarker in Oncology Studies

BACKGROUND

Improving experimental conditions in preclinical animal research is a major challenge, both scientifically and ethically. Automated digital ventilated cages (DVC®) offer the advantage of continuous monitoring of animal activity in their home-cage. The potential utility of this technology remains understudied and deserves investigation in the field of oncology.

METHODS

Using the DVC® platform, we sought to determine if the continuous assessment of locomotor activity of mice in their home cages can serve as useful digital readout in the monitoring of animals treated with the reference oncology compounds cisplatin and cyclophosphamide. SCID mice of 14 weeks of age were housed in DVC® cages in groups of four and followed with standard and digital examination before and after treatment over a 17-day total period.

RESULTS

DVC® detected statistically significant effects of cisplatin on the activity of mice in the short and long term, as well as trends for cyclophosphamide. The activity differences between the vehicle- and chemotherapy-treated groups were especially marked during the nighttime, a period when animals are most active and staff are generally not available for regular checks. Standard clinical parameters, such as body weight change and clinical assessment during the day, provided additional and complementary information.

CONCLUSION

The DVC® technology enabled the home cage monitoring of mice and non-invasive detection of animal activity disturbances. It can easily be integrated into a multimodal monitoring approach to better capture the different effects of oncology drugs on anti-tumor efficacy, toxicity, and safety and improve translation to clinical studies.

Evaluation of Dithiocarbamate-Modified Silica for Cisplatin Removal from Water

Despite the globally increasing use of platinum-based cytostatic drugs in the treatment of several types of cancer, only limited attention has been paid to developing a treatment for contaminated liquid samples originating from hospitals, laboratories and manufacturing facilities before and after their administration. In this work, we assess the efficiency of a low-cost adsorbent material, a dithiocarbamate-functionalized silica, in removing cisplatin from a solution containing it in the 0.5–150 mg L−1 concentration range. The advantage of having a surface-functionalized silica is that adsorption can occur by either non-covalent interaction or surface complexation. In the latter case platinum(II) is de-complexed and the original drug is no longer present. Adsorption occurs through a first rapid step, followed by a second slower process. This is likely due to the fact that in our operating conditions (0.9% w/v NaCl), only the original compound is present, for which ligand substitution is known to proceed slowly. The interesting performance, even at low metal concentration, and facile synthesis of the material mean it could be adapted for other applications where the recycling of platinum can be realized.

Zebrafish embryos as an in vivo model to investigate cisplatin-induced oxidative stress and apoptosis in mitochondrion-rich ionocytes

Pharmaceuticals and personal care products are emerging environmental pollutants. Cisplatin, one of the most widely used platinum-based chemotherapeutic agents, has been found to contaminate aquatic environments. Using zebrafish embryos as a model, cisplatin was previously found to impair skin ionocytes and ion regulation. The purpose of this study was to further investigate how cisplatin damages ionocytes. Zebrafish embryos were exposed to cisplatin (0, 50, and 100 μM) for 96 h (4-100 h post-fertilization) and then stained with fluorescent dyes to reveal mitochondrial activity (rhodamine123), apoptosis (acridine orange), and oxidative stress (CellROX/MitoSOX) in ionocytes of living embryos. Results showed that cisplatin exposure decreased rhodamine 123-labeled ionocytes, induced oxidative stress in ionocytes, and promoted apoptosis in a concentration-dependent manner. Quantitative PCR analysis showed that mRNA levels of antioxidative genes (sod1, sod2, gpx1a, and cat) and an apoptotic gene (caps3a) were induced. In the time-course experiment at 96-98 h post-fertilization, cisplatin increased oxidative stress and apoptosis in ionocytes in a time-dependent manner. In conclusion, this study demonstrates that cisplatin exposure induces oxidative stress, mitochondrial damage, and apoptosis in ionocytes of zebrafish embryos.

Anticancer Drugs: Recent Strategies to Improve Stability Profile, Pharmacokinetic and Pharmacodynamic Properties

In past decades, anticancer research has led to remarkable results despite many of the approved drugs still being characterized by high systemic toxicity mainly due to the lack of tumor selectivity and present pharmacokinetic drawbacks, including low water solubility, that negatively affect the drug circulation time and bioavailability. The stability studies, performed in mild conditions during their development or under stressing exposure to high temperature, hydrolytic medium or light source, have demonstrated the sensitivity of anticancer drugs to many parameters. For this reason, the formation of degradation products is assessed both in pharmaceutical formulations and in the environment as hospital waste. To date, numerous formulations have been developed for achieving tissue-specific drug targeting and reducing toxic side effects, as well as for improving drug stability. The development of prodrugs represents a promising strategy in targeted cancer therapy for improving the selectivity, efficacy and stability of active compounds. Recent studies show that the incorporation of anticancer drugs into vesicular systems, such as polymeric micelles or cyclodextrins, or the use of nanocarriers containing chemotherapeutics that conjugate to monoclonal antibodies can improve solubility, pharmacokinetics, cellular absorption and stability. In this study, we summarize the latest advances in knowledge regarding the development of effective highly stable anticancer drugs formulated as stable prodrugs or entrapped in nanosystems.