Thiolated chitosan nanoparticles for stable delivery and smart release of As2O3 for liver cancer through dual actions

In this work, multifunctional thiolated chitosan derivatives (DCA-CS-PEG-FA-NAC) were synthesized, and arsenic trioxide (ATO) was loaded onto the derivatives through glutathione (GSH)-sensitive As^III-S bonds, and stable CS-ATO nanodrugs were prepared by simple self-assembly method. By adjusting the thiol substitution degree of CS, the drug loading capacity of the nanodrugs was significantly improved, which could reach 20 ATO per CS molecule (DCA_10.7-CS-PEG_3.1-FA-NAC_20.2-ATO). In vitro release studies obviously showed the low leakage of ATO under physiological conditions while over 95 % ATO was released after 24 h under GSH. In vitro and in vivo investigations demonstrated that the DCA_10.7-CS-PEG_3.1-FA-NAC_20.2-ATO nanodrug could significantly enhance the tumor intracellular accumulation of ATO, reduce the toxic and side effects of ATO on healthy organs, and improve the therapeutic effect of ATO on the HepG2 mice tumor model (tumor inhibition rate was as high as 86.4 %), indicating the potential application of ATO in clinical treatment of liver cancer.

Arsenic trioxide activates yes-associated protein by lysophosphatidic acid metabolism to selectively induce apoptosis of vascular smooth muscle cells

Inhibition of vascular smooth muscle cells (VSMCs) proliferation without dysregulating endothelial cells (ECs) may provide an ideal therapy for in-stent restenosis. Due to its anti-proliferation effect on VSMCs and pro-endothelium effect, arsenic trioxide (ATO) has been used in a drug-eluting stent in a recent clinical trial. However, the underlying mechanism by which ATO achieves this effect has not been determined. In the present work, we showed that ATO induced apoptosis in VSMCs but not in ECs. Mechanistically, ATO achieved this through modulation of cellular metabolism to increase lysophosphatidic acid (LPA) in VSMCs, while LPA concentration was stable in ECs. The elevated LPA facilitated the nuclear accumulation and initiated the transcriptional function of Yes-associated protein (YAP) in VSMCs. YAP regulated the transcription of N6-Methyladenosine (m⁶A) modulators (Mettl14 and Wtap) to increase the m⁶A methylation levels of apoptosis-related genes to induce their high expression and exacerbate VSMCs apoptosis. On the other hand, YAP nuclear accumulation in ECs was not observed. Collectively, our data exhibited the molecular process involved in selective apoptosis of VSMCs induced by ATO.

Iodide Analogs of Arsenoplatins-Potential Drug Candidates for Triple Negative Breast Cancers

Patients with triple negative breast cancers (TNBCs)—highly aggressive tumors that do not express estrogen, progesterone, and human epidermal growth factor 2 receptors—have limited treatment options. Fewer than 30% of women with metastatic TNBC survive five years after their diagnosis, with a mortality rate within three months after a recurrence of 75%. Although TNBCs show a higher response to platinum therapy compared to other breast cancers, drug resistance remains a major obstacle; thus, platinum drugs with novel mechanisms are urgently needed. Arsenoplatins (APs) represent a novel class of anticancer agents designed to contain the pharmacophores of the two FDA approved drugs cisplatin and arsenic trioxide (As₂O₃) as one molecular entity. Here, we present the syntheses, crystal structures, DFT calculations, and antiproliferative activity of iodide analogs of AP-1 and AP-2, i.e., AP-5 and AP-4, respectively. Antiproliferative studies in TNBC cell lines reveal that all AP family members are more potent than cisplatin and As₂O₃ alone. DFT calculations demonstrate there is a low energy barrier for hydrolysis of the platinum-halide bonds in arsenoplatins, possibly contributing to their higher cytotoxicities compared to cisplatin.

Antibacterial, antifungal and enzymatic activities of azithromycin-heavy metal complexes: Newly synthesized and characterized

As part of our continuous research to understand the interaction mechanism of drug and metallo-elements, heavy metal complexes of azithromycin (AZI) were synthesized with arsenic oxide, lead carbonate and silver chloride salts in molar ratio of 2: 1 (L: M). Synthesized heavy metal complexes have shown good percent yield and characterized through spectroscopic parameters including UV-Visible, TLC, FT-IR, NMR and elemental analysis (CHN). Spectroscopic characterization reveals the binding of ligand AZI with heavy metals in bi-dentate manner involving the hydroxide and 9a-NCH₃ group of the aglycone ring of AZI. These newly synthesized heavy metal complexes were evaluated for their antimicrobial response against selected gram positive and gram negative organisms and antifungal species. It was noted that all newly synthesized complexes exhibits increased activity against B.subtilus whereas, AZI itself didn't show any activity, while synthesized complexes have low to moderate response against all the studied organisms. Complex A-M12 possess greater enzymatic response against both urease and alpha chymotrypsin among all the studied complexes. Results obtained were then statistically analyzed through one way ANOVA and Dunnett's test by using SPSS version 20.0 suggesting the significant response of complexes against selected organisms.

Zeolitic Imidazolate Framework-8 as pH-Sensitive Nanocarrier for "Arsenic Trioxide" Drug Delivery

Previous results revealed that arsenic trioxide might be used as promising therapeutic agent for the treatment of some solid tumours as atypical teratoid rhabdoid tumours (ATRT). However, in order to become an approved drug for solid tumour treatment, the active formulation has to get more efficient and feasible-but at the same time less toxic. One of the possibilities to achieve this dichotomy is to use nanomedicine tools. Herein, we report on the Zn-based metal-organic framework ZIF-8 (Zeolitic Imidazolate Framework-8) which turned out to be a promising candidate for the delivery of AsIII species. It conjointly features a high drug loading capacity and a prominent pH-triggered release behaviour. AsIII -loaded ZIF-8 nanoparticles coated and non-coated with polyethylene glycol were studied by XRPD, IR, Raman, TGA, TEM, EDX, CHN-elemental analysis, sorption analysis and ICP-OES, and their cytotoxicity was evaluated in vitro.

Characterization of arsenic oxidation and uranium bioremediation potential of arsenic resistant bacteria isolated from uranium ore

Arsenic (As) is often found naturally as the co-contaminant in the uranium (U)-contaminated area, obstructing the bioremediation process. Although the U-contaminated environment harbors microorganisms capable of interacting with U which could be exploited in bioremediation. However, they might be unable to perform with their full potential due to As toxicity. Therefore, potential in arsenic resistance and oxidation is greatly desired among the microorganisms for a continued bioremediation process. In this study, arsenic-resistant bacteria were isolated from U ore collected from Bundugurang U mine, characterized and their As oxidation and U removal potentials were determined. 16S rRNA gene sequencing and phylogenetic analysis showed the affiliation of isolated bacteria with Microbacterium, Micrococcus, Shinella, and Bacillus. Except Bacillus sp. EIKU7, Microbacterium sp. EIKU5, Shinella sp. EIKU6, and Micrococcus sp. EIKU8 were found to resist more than 400 mM As(V); however, all the isolates could survive in 8 mM As(III). The isolates were found to readily oxidize As under different culture conditions and are also resistant towards Cd, Cr, Co, Ni, and Zn. All the isolates could remove more than 350 mg U/g dry cells within 48 h which were found to be highly dependent upon the concentration of U, biomass added initially, and on the time of exposure. Ability of the isolates to grow in nitrogen-free medium indicated that they can flourish in the nutrition deprived environment. Therefore, the recovery of isolates with the potent ability to resist and oxidize As from U ore might play an important role in toxic metal bioremediation including U.

Arsenoplatin-1 Is a Dual Pharmacophore Anticancer Agent

Arsenoplatins are adducts of two chemically important anticancer drugs, cisplatin and arsenic trioxide, that have a Pt(II) bond to an As(III) hydroxide center. Screens of the NCI-60 human tumor cell lines reveal that arsenoplatin-1 (AP-1), [Pt(μ-NHC(CH3)O)2ClAs(OH)2], the first representative of this novel class of anticancer agents, displays a superior activity profile relative to the parent drugs As2O3 or cisplatin in a majority of cancer cell lines tested. These activity profiles are important because the success of arsenic trioxide in blood cancers (such as APL) has not been seen in solid tumors due to the rapid clearance of arsenous acid from the body. To understand the biological chemistry of these compounds, we evaluated interactions of AP-1 with the two important classes of biomolecules-proteins and DNA. The first structural studies of AP-1 bound to model proteins reveal that platinum(II) binds the Nε of His in a manner that preserves the Pt-As bond. We find that AP-1 readily enters cells and binds to DNA with an intact Pt-As bond (Pt:As ratio of 1). At longer incubation times, however, the Pt:As ratio in DNA samples increases, suggesting that the Pt-As bond breaks and releases the As(OH)2 moiety. We conclude that arsenoplatin-1 has the potential to deliver both Pt and As species to a variety of hematological and solid cancers.

Surface-modified PLGA nanoparticles with PEG/LA-chitosan for targeted delivery of arsenic trioxide for liver cancer treatment: Inhibition effects enhanced and side effects reduced

Arsenic trioxide (As₂O₃), an effective drug for leukemia, is limited to be used for solid tumor treatment due to its high side effects. In this study, polyethylene glycol (PEG) and lactobionic acid (LA) modified chitosan (PLC) was synthesized and was used to coat poly(lactide-co-glycolide) (PLGA) nanoparticles for encapsulation and targeted release of As₂O₃ in liver cancer treatment. The As₂O₃-loaded PLGA/PLC nanoparticles (As₂O₃-PLGA/PLC NPs) were fabricated through double emulsion-solvent evaporation method and were optimized by orthogonal tests. As₂O₃-PLGA/PLC NPs presented suitable physical stability, positive charge, high encapsulation efficiency and drug loading, and good biocompatibility. As expected, the NPs can quickly release enough dose of As₂O₃ in a short time and then sustain the drug concentration. The As₂O₃-PLGA/PLC NPs showed effective inhibition of SMMC-7721 cells while having lower cytotoxicity against normal human liver cells (LO2 cells). Furthermore, In vivo study showed that the NPs did not present toxic effects on kidney and liver, but showed relatively high growth inhibition effect on liver tumor. Therefore, this PLGA/PLC NPs could be an effective and safe drug delivery system for liver cancer chemotherapy.

Arsenic trioxide and/or copper sulfate induced apoptosis and autophagy associated with oxidative stress and perturbation of mitochondrial dynamics in the thymus of Gallus gallus

Arsenic (As) and copper (Cu) are ubiquitous environmental contaminants that are hazardous to the immune system. Our objective was to investigate the toxicity and potential mechanisms of thymus exposure to As and/or Cu. A chicken model was established by adding arsenic trioxide (As₂O₃; 30 mg/kg), copper sulfate (CuSO₄; 300 mg/kg), and simultaneously both elements in the basal diet. After the chickens were fed for 12 weeks, a significant reduction in antioxidant enzyme levels or production of malondialdehyde (MDA) emphasized the occurrence of oxidative stress. Furthermore, an imbalance in mitochondrial dynamics along with its abnormal structure certified mitochondrial dysfunction. Additionally, elevated levels of pro-apoptotic and autophagy genes and decreased levels of antiapoptotic genes were found in treated groups. Karyopyknosis and chromatin peripheral condensation were accompanied by an increased apoptosis ratio, as well as accumulation of autophagosomes, thus indicating that apoptosis and autophagy are involved in immune cell death. All of the above thymus lesions and index abnormalities occurred in a time-dependent manner, and the Cu and As co-administered groups showed more deteriorating effects than the Cu and As groups alone. Moreover, in the As or Cu group, the thymus tissue suffered different susceptibilities in oxidative toxicity, which needs further study. Collectively, our results manifested that co-exposure to As and Cu increased the oxidative burden and exacerbated mitochondrial dysfunction on the thymus. Additionally, apoptosis and autophagy may act as partners in inducing cell death in a cooperative manner in chicken thymus after As and/or Cu exposure.

In vitro stability of arsenic trioxide-liposome encapsulates for acute promyelocytic leukemia treatment

In this work, we investigated the stability of arsenic trioxide (ATO) used in leukemia treatment, encapsulated with nanoliposome, with the aid of ultrasound treatment. Stability studies of As species were followed by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS), allowing for the detection of the conversion of low amounts of As(III) to As(V) or the formation of other As species. The influence of storage temperature and time on ATO was evaluated. Low amounts of As(III) to As(V) conversions were observed when the As encapsulated with nanoliposome was incubated at 25 °C and 40 °C. However, As(III) was stable if the solution was maintained at 5 °C, even after 90 days. No formation of other As species was observed, indicating good stability of the encapsulated ATO. Next step of the work will focus on spray drying of ATO nanoliposomes-encapsuleted with the aim of long term stability of As.

Smart Human-Serum-Albumin-As2 O3 Nanodrug with Self-Amplified Folate Receptor-Targeting Ability for Chronic Myeloid Leukemia Treatment

Arsenic trioxide (ATO, As2 O3 ) is currently used to treat acute promyelocytic leukemia. However, expanding its use to include high-dose treatment of other cancers is severely hampered by serious side effects on healthy organs. To address these limitations, we loaded ATO onto folate (FA)-labeled human serum albumin (HSA) pretreated with glutathione (GSH) based on the low pH- and GSH-sensitive arsenic-sulfur bond, and we termed the resulting smart nanodrug as FA-HSA-ATO. FA-HSA-ATO could specifically recognize folate receptor-β-positive (FRβ+) chronic myeloid leukemia (CML) cells, resulting in more intracellular accumulation of ATO. Furthermore, the nanodrug could upregulate FRβ expression in CML cancer cells and xenograft tumor model, facilitating even more recruitment and uptake of FRβ-targeting drugs. In vitro and in vivo experiments indicate that the nanodrug significantly alleviates side effects and improves therapeutic efficacy of ATO on CML and xenograft tumor model.