Toxicity Of Arsenic Trioxide Research Articles

A Tumor Homing Peptide-Linked Arsenic Compound Inhibits Pancreatic Cancer Growth and Enhances the Inhibitory Effect of Gemcitabine.

Arsenic trioxide (ATO) has been shown to inhibit pancreatic cancer (PC) cell growth in vitro and to promote the inhibitory effects of gemcitabine (Gem) on PC in vivo. However, the high toxicity of ATO associated with the required high doses and indiscriminate targeting has limited its clinical application. This study aimed to determine whether coupling arsenic to a tumor homing peptide would increase the inhibitory potency against PC cells. The effects of this peptide-linked arsenic compound (PhAs-LHP), the analogous non-targeting arsenic compound (phenylarsine oxide, PAO), and marketed ATO on PC growth were tested in vitro and in a mouse model. The data demonstrated that PhAs-LHP inhibited PC cell growth in vitro more potently, with IC50 values 10 times lower than ATO. Like ATO, PhAs-LHP induced cell death and cell cycle arrest. This cytotoxic effect of PhAs-LHP was mediated via a macropinocytosis-linked uptake pathway as amiloride (a macropinocytosis inhibitor) reduced the inhibitory effect of PhAs-LHP. More importantly, PhAs-LHP inhibited PC growth in mice and enhanced the inhibitory effect of Gem on PC growth at 2 times lower molar concentration than PAO. These results indicate that PhAs-LHP inhibited PC more potently than ATO/PAO and suggest a potential clinical use for the combination of Gem with the peptide-linked arsenic compound for the treatment of pancreatic cancer.

Alteration of Hepatic Cytochrome P450 Expression and Arachidonic Acid Metabolism by Arsenic Trioxide (ATO) in C57BL/6 Mice.

The success of arsenic trioxide (ATO) in acute promyelocytic leukemia has driven a plethora studies to investigate its efficacy in other malignancies. However, the inherent toxicity of ATO limits the expansion of its clinical applications. Such toxicity may be linked to ATO-induced metabolic derangements of endogenous substrates. Therefore, the primary objective of this study was to investigate the effectof ATO on the hepatic formation of arachidonic acid (AA) metabolites, hydroxyeicosatetraenoic acids (HETEs), as well as their most notable producing machinery, cytochrome P450 (CYP) enzymes. For this purpose, C57BL/6 mice were intraperitoneally injected with 8 mg/kg ATO for 6 and 24 h. Total RNA was extracted from harvested liver tissues for qPCR analysis of target genes. Hepatic microsomal proteins underwent incubation with AA, followed by identification/quantification of the produced HETEs. ATO downregulated Cyp2e1, while induced Cyp2j9 and most of Cyp4a and Cyp4f, and this has resulted in a significant increase in 17(S)-HETE and 18(R)-HETE, while significantly decreased 18(S)-HETE. Additionally, ATO induced Cyp4a10, Cyp4a14, Cyp4f13, Cyp4f16, and Cyp4f18, resulting in a significant elevation in 20-HETE formation. In conclusion, ATO altered hepatic AA metabolites formation through modulating the underlying network of CYP enzymes. Modifying the homeostatic production of bioactive AA metabolites, such as HETEs, may entail toxic events that can, at least partly, explain ATO-induced hepatotoxicity. Such modification can also compromise the overall body tolerability to ATO treatment in cancer patients.

POSTER: AML-159 Case Report: Successful Management of Unusual Toxicity of Arsenic Trioxide (ATO) on Day 10 of Consolidation in Acute Promyelocytic Leukemia (APL)

POSTER: AML-159 Case Report: Successful Management of Unusual Toxicity of Arsenic Trioxide (ATO) on Day 10 of Consolidation in Acute Promyelocytic Leukemia (APL)

AML-159 Case Report: Successful Management of Unusual Toxicity of Arsenic Trioxide (ATO) on Day 10 of Consolidation in Acute Promyelocytic Leukemia (APL)

AML-159 Case Report: Successful Management of Unusual Toxicity of Arsenic Trioxide (ATO) on Day 10 of Consolidation in Acute Promyelocytic Leukemia (APL)

Arsenic trioxide liposome gels for the treatment of psoriasis in mice

Psoriasis is a chronic, immune-mediated skin disease with no cure. Intravenous arsenic trioxide (ATO) has been used to treat psoriasis in animal studies. However, the high toxicity of ATO limits its application to clinics for systemic administration. The aim of this study was to fabricate sustained-release ATO liposome gels (ATO-Lip-Gels) to be used for the treatment of psoriasis. The ATO Liposomes were prepared using a zinc acetate gradient method. ATO concentrations were analyzed by HPLC-HG-AFS. The ATO-Lip-Gels were characterized with respect to size, zeta potential, and entrapment efficiency. Stability, in vitro drug release, and in vivo efficacy were also evaluated. The optimal formulation of ATO-Lip was ATO (0.45%), S100 (9%), and cholesterol (1.5%) (W/V) in 0.3 mol/L zinc acetate and incubated for 10 min. In the in vitro drug release study, ATO-Lip-Gels exhibited a slower release profile of ATO than that from Gels only. Compared with the model group, ATO-Lip-Gels-H significantly reduced PASI scores after psoriasis in mice and was superior to tacrolimus at day 5. HE staining showed that the pathological changes caused by psoriasis in mice were significantly improved in the treatment groups, and ATO-Lip-Gels-H had the best effect among the treatment groups. ATO-Lip-Gels applied topologically to imiquimote-induced psoriatic plaque models significantly reduced the levels of key psoriatic cytokines such as IL-6 and TNF-α. We have developed ATO-Lip-Gels for the treatment of psoriasis, which demonstrated higher efficacy with the benchmark, Tacrolimus, and can be an alternative to the conventional treatment with Tacrolimus.

The impact of Annona muricata and metformin on semen quality and hormonal profile in Arsenic trioxide-induced testicular dysfunction in male Wistar rat

Male Infertility has been an issue of significant concern affecting an appraised 20-30% of couples worldwide. The study aims to access the hormonal and semen profile following metformin and ethanolic leave extract of Annona muricata (ELAM) on arsenic-induced toxicity in Male Wistar rats. Thirty-male Wistar rats were used in the study, weighing 150-170 grams, and were divided into six groups of five rats each. Group A received 50 mg/kg of arsenic trioxide (As2O3) only. Group B received feed and water ad libitum. Groups C and D received 50mg/kg of As2O3 and were immediately treated with 30 mg/kg of metformin and 500 mg/kg of ELAM. Group E received 500mg/kg of ELAM and treated immediately with As2O3, and group F received 30 mg/kg of metformin and treated immediately with As2O3. Data obtained were subjected to ANOVA followed by post Hoc LSD using SPSS version 25. Semen quality, Testosterone, FSH, LH levels, and gonadal-somatic index were analysed. Values were presented as Mean±SEM and considered significant at p<0.05. The gonadal-somatic index revealed a significant decrease in group D, while groups B, C, E, and F had no significant decrease compared to A. As2O3 treated rats showed impaired sperm motility, morphology, and total sperm count significantly in groups A to B, while groups C, D, E, and F improved sperm motility, morphology, and total sperm count. Testosterone, LH, and FSH showed a significant decline in group A compared to B, except for LH. Groups C, D, E, and F showed a significant increase in testosterone and LH, except group C in FSH. The study concluded that MET and ELAM improved semen quality and hormonal profile, which could be used in the reversing and prevention of male infecundity linked to arsenic trioxide toxicity caused by oxidative stress.

Galbanic Acid Improves Accumulation and Toxicity of Arsenic Trioxide in MT-2 Cells.

Galbanic acid (GBA) is a sesquiterpene coumarin with valuable pharmacological effects. Adult T-cell lymphoma (ATL) is an aggressive lymphoid malignancy with a low survival rate. Although arsenic trioxide (ATO) is a standard therapeutic agent for ATL treatment, the efficacy of chemotherapy is limited due to the chemoresistance of cells. The present study was carried out to investigate whether GBA in combination with ATO would improve cytotoxicity against ATL cells. GBA was isolated from the roots of Ferula szowitsiana by column chromatography on silica gel. MT-2 cells were treated with 20 μM GBA + 4 μM ATO, and viability was evaluated by alamarBlue assay. The cell cycle was analyzed by PI staining, while the activity of P-glycoprotein (P-gp) was evaluated by mitoxantrone efflux assay. To understand the molecular mechanisms of GBA effects, the expression of NF-κB (RelA), P53, CDK4, c-MYC, c-FLIPL, and c-FLIPS was evaluated using real-time PCR. Combinatorial use of GBA + ATO significantly reduced the viability of MT-2 cells and induced cell cycle arrest in the sub-G1 phase. GBA improved mitoxantrone accumulation in cells, indicating that this agent has inhibitory effects on the functionality of the P-gp efflux pump. Moreover, real-time PCR analysis revealed that GBA + ATO negatively regulated the expression of P53, CDK4, c-FLIPL, and c-FLIPS. Due to the interesting effects of GBA on the accumulation and toxicity of ATO, combinatorial use of these agents could be considered a new therapeutic approach for ATL treatment.

PEG-grafted arsenic trioxide-loaded mesoporous silica nanoparticles endowed with pH-triggered delivery for liver cancer therapy.

Liver cancer (LC), one of the most common malignant primary tumors, presents a poor prognosis, high morbidity rate, and poor clinical outcomes. Despite conventional treatments have been applied prior to the deterioration, their clinical benefits were still limited. Arsenic trioxide (ATO), a toxic Chinese medicine, has been proven to efficiently inhibit the growth of LC both in vitro and in vivo. However, its therapeutic effects are hindered by poor pharmacokinetics and dose-limited toxicity. In this study, we developed a pH-responsive nanoplatform (PEG-MSN@ATO) consisting of mesoporous silica nanoparticles (MSN) that were modified with amino groups, loaded with ATO, and grafted with PEG to achieve the pH-triggered release and regulate CD8+ T cells and Treg cells in the tumor microenvironment (TME). PEG-MSN@ATO were characterized by uniform size, good loading efficiency, pH-responsive release features, decreased macrophage uptake, and enhanced dendritic cell activation in vitro. Furthermore, in vivo studies demonstrated that PEG-MSN@ATO enhanced the antitumor efficacy by inducing apoptosis and ROS production, inhibiting tumor cell proliferation and metastasis, and activating antitumor immunity within the TME. PEG-MSN@ATO also reduced the system toxicity of ATO by controlling the pH-trigger release in the tumor site. These results indicate that the PEG-MSN@ATO represents a promising drug delivery platform for reducing toxicity and enhancing the therapeutic efficacy of ATO against LC.

In silico mechanisms of arsenic trioxide-induced cardiotoxicity.

It has been found that arsenic trioxide (ATO) is effective in treating acute promyelocytic leukemia (APL). However, long QT syndrome was reported in patients receiving therapy using ATO, which even led to sudden cardiac death. The underlying mechanisms of ATO-induced cardiotoxicity have been investigated in some biological experiments, showing that ATO affects human ether-à-go-go-related gene (hERG) channels, coding rapid delayed rectifier potassium current (I Kr ), as well as L-type calcium (I CaL ) channels. Nevertheless, the mechanism by which these channel reconstitutions induced the arrhythmia in ventricular tissue remains unsolved. In this study, a mathematical model was developed to simulate the effect of ATO on ventricular electrical excitation at cellular and tissue levels by considering ATO's effects on I Kr and I CaL . The ATO-dose-dependent pore block model was incorporated into the I Kr model, and the enhanced degree of ATO to I CaL was based on experimental data. Simulation results indicated that ATO extended the action potential duration of three types of ventricular myocytes (VMs), including endocardial cells (ENDO), midmyocardial cells (MCELL), and epicardial cells (EPI), and exacerbated the heterogeneity among them. ATO could also induce alternans in all three kinds of VMs. In a cable model of the intramural ventricular strand, the effects of ATO are reflected in a prolonged QT interval of simulated pseudo-ECG and a wide vulnerable window, thus increasing the possibility of spiral wave formation in ventricular tissue. In addition to showing that ATO prolonged QT, we revealed that the heterogeneity caused by ATO is also an essential hazard factor. Based on this, a pharmacological intervention of ATO toxicity by resveratrol was undertaken. This study provides a further understanding of ATO-induced cardiotoxicity, which may help to improve the treatment for APL patients.

Arsenic trioxide and Erlotinib loaded in RGD-modified nanoliposomes for targeted combination delivery to PC3 and PANC-1 cell lines.

During the past few years, advances in drag delivery have provided many opportunities in the treatment of various diseases and cancer. Arsenic trioxide (ATO) and Erlotinib (Erlo) are two drugs, approved by the United States Food and Drug Administration to treat cancer, but their use is limited in terms of the toxicity of ATO and the low solubility of Erlo. This study aimed to prepare arginine-glycine-aspartic acid (RGD)-decorated nanoliposomes (NLPs) containing Erlo and ATO (NLPs-ATO-Erlo-RGD) to increase the solubility and reduce the toxicity of Erlo and ATO for cancer treatment. The results of transmission electron microscopy and dynamic light scattering showed that NLPs were synthesized uniformly, with spherical shape morphology and particle sizes between 140 and 160nm. High-performance liquid chromatography and ICP-MS results showed that about 90% of the drug was loaded in the NLPs. In comparison with NLPs-ATO-Erlo, NLPs-ATO-Erlo-RGD demonstrated considerable toxicity against the αvβ3 overexpressing PC3 cell line in the MTT experiment. It had no effect on the PANC-1 cell line. In addition, apoptosis assays using Annexin V/PI demonstrated that NLPs-ATO-Erlo-RGD generated the highest apoptotic rates in PC3 cells when compared with NLPs-ATO-Erlo and the combination of free ATO and Erlo. Furthermore, treatment with NLPs-ATO-Erlo-RGD in (p<0.05) PC3 cell line significantly reduced EGFR level. It is concluded NLPs-ATO-Erlo-RGD as a novel drug delivery system may be a promising platform for the treatment of cancer.

P53 as a unique target of action of cisplatin in acute leukaemia cells.

Acute promyelocytic leukaemia (APL) occurs in approximately 10% of acute myeloid leukaemia patients. Arsenic trioxide (ATO) has been for APL chemotherapy, but recently several ATO‐resistant cases have been reported worldwide. Cisplatin (CDDP) enhances the toxicity of ATO in ovarian, lung cancer, chronic myelogenous leukaemia, and HL‐60 cells. Hence, the goal of this study was to investigate a novel target of CDDP action in APL cells, as an alternate option for the treatment of ATO‐resistant APL patients. We applied biochemical, molecular, confocal microscopy and advanced gene editing (CRISPR‐Cas9) techniques to elucidate the novel target of CDDP action and its functional mechanism in APL cells. Our main findings revealed that CDDP activated p53 in APL cells through stress signals catalysed by ATM and ATR protein kinases, CHK1 and CHK2 phosphorylation at Ser 345 and Thr68 residues, and downregulation and dissociation of MDM2‐DAXX‐HAUSP complex. Our functional studies confirmed that CDDP‐induced repression of MDM2‐DAXX‐HAUSP complex was significantly reversed in both nutilin‐3‐treated KG1a and p53‐knockdown NB4 cells. Our findings also showed that CDDP stimulated an increased number of promyelocytes with dense granules, activated p53 expression, and downregulated MDM2 in liver and bone marrow of APL mice. Principal conclusion of our study highlights a novel mode of action of CDDP targeting p53 expression which may provide a basis for designing new anti‐leukaemic compounds for treatment of APL patients.

Curcumin antagonizes inflammation and autophagy induced by arsenic trioxide through immune protection in duck spleen.

Arsenic is a toxic heavy metal widely found in the natural environment and has adverse effects on the health of waterfowl and human. Curcumin (CUR), a natural pigment of the golden spice turmeric, exhibits excellent anti-tumor, anti-inflammatory and anti-oxidant activities. But the effects of CUR on duck spleen exposed to arsenic remain largely unknown. In this study, 75 ducks were divided randomly into Control, L-ATO, M-ATO, H-ATO and CUR + H-ATO groups to systematically analyze the underlying role of CUR. The results showed that arsenic trioxide (ATO) led to growth retardation of ducks, hyaline degeneration and sparse cell arrangement on their spleen. And in the ATO-exposed ducks, the levels of immunoglobulins (Ig; IgA, IgG, IgM) in the serum and the expression of autophagy-related genes (Atg5, P62, LC3I, LC3II, LC3II/I, Beclin-1) were significantly upregulated compared with the control ducks. Moreover, ATO also activated NF-κB signal pathway and upregulated the expression of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β, IL-2, IL-18). Meanwhile, application of CUR alleviated the ATO toxicity with the release of growth inhibition, and the reduced hyaline degeneration and distortion of the spleen capsule. CUR also suppressed ATO-induced NF-κB activation, pro-inflammatory cytokine addition and expression of autophagy-related genes. Overall, these results suggested that CUR might exert a protective effect against ATO-induced immunosuppression in ducks via anti-inflammation and autophagy restoring.

Combination of Umbelliprenin and Arsenic Trioxide Acts as an Effective Modality Against T-Cell Leukemia/Lymphoma Cells

Adult T-cell leukemia/lymphoma (ATLL) is a serious blood malignancy with distinct geographical distribution. ATLL patients have a short survival time because of intrinsic chemoresistance and severe immunosuppression. To introduce a novel treatment, we investigated whether umbelliprenin (UMB), a natural coumarin derivative, could improve the toxicity of arsenic trioxide (ATO) on ATLL cells. To determine the viability of MT-2 cells upon treatment with different concentrations of UMB and ATO, alamarBlue assay was applied. Cell cycle analysis was carried out by propidium iodide staining and the expression of candidate genes was assessed by quantitative reverse transcription-polymerase chain reaction. Our findings revealed that combination of UMB and ATO induced considerable cytotoxic effects on ATLL cells. Flow cytometry analysis indicated accumulation of MT-2 cells in the sub G1 phase of the cell cycle after combinatorial treatment. In addition, significant downregulation in BMI-1, CD44, c-MYC, and nuclear factor-κB (REL-A) expression was observed after UMB + ATO administration. Agents with low side effects are potential candidates for novel cancer treatments. We demonstrated, for the first time, that combination of UMB and ATO might be regarded as an effective regimen for ATLL treatment.

Curcumin alleviates arsenic-induced injury in duck skeletal muscle via regulating the PINK1/Parkin pathway and protecting mitochondrial function

Arsenic is a well-known environmental pollutant due to its toxicity, which can do harm to animals and human. Curcumin is a polyphenolic compound derived from turmeric, commonly accepted to have antioxidant properties. However, whether curcumin can ameliorate the damage caused by arsenic trioxide (ATO) in duck skeletal muscle remains largely unknown. Therefore, the present study aims to investigate the potential molecular mechanism of curcumin against ATO-induced skeletal muscle injury. The results showed that treating with curcumin could attenuate body weight loss induced by ATO and reduced arsenic content accumulation in the skeletal muscle of duck. Curcumin was also able to alleviated the oxidative stress triggered by ATO, which was manifested by the increase of T-AOC and SOD, and MDA decrease. Moreover, we observed that curcumin could ease mitochondrial damage and vacuolate degeneration of nucleus. Our further investigation found that ATO disrupted normal mitochondrial fission/fusion (Drp1, OPA1, Mfn1/2) and restrained mitochondrial biogenesis (PGC-1α, Nrf1/2, TFAM), while curcumin could promote mitochondrial fusion and activated PGC-1α pathway. Furthermore, curcumin was found that it could not only reduce the mRNA and protein levels of mitophagy (PINK1, Parkin, LC3, p62) and pro-apoptotic genes (p53, Bax, Caspase-3, Cytc), but also increased the levels of anti-apoptotic genes (Bcl-2). In conclusion, curcumin was able to alleviate ATO-induced skeletal muscle damage by improving mitophagy and preserving mitochondrial function, which can serve as a novel strategy to take precautions against ATO toxicity.

Combination of auraptene and arsenic trioxide induces apoptosis and cellular accumulation in the subG1 phase in adult T-cell leukemia cells.

Objective(s):Despite advances in the treatment of adult T-cell leukemia/lymphoma (ATLL), the survival rate of this malignancy remains significantly low. Auraptene (AUR) is a natural coumarin with broad-spectrum anticancer activities. To introduce a more effective therapeutic strategy for ATLL, we investigated the combinatorial effects of AUR and arsenic trioxide (ATO) on MT-2 cells.Materials and Methods:The cells were treated with different concentrations of AUR for 24, 48, and 72 hr, and viability was measured by alamarBlue assay. Then, the combination of AUR (20 μg/ml) and ATO (3 μg/ml) was administrated and the cell cycle was analyzed by PI staining followed by flow cytometry analysis. In addition, the expression of NF-κB (REL-A), CD44, c-MYC, and BMI-1 was evaluated via qPCR.Results:Assessment of cell viability revealed increased toxicity of AUR and ATO when used in combination. Our findings were confirmed by accumulation of cells in the sub G1 phase of the cell cycle and significant down-regulation of NF-κB (REL-A), CD44, c-MYC, and BMI-1.Conclusion:Obtained findings suggest that combinatorial use of AUR and ATO could be considered for designing novel chemotherapy regimens for ATLL.

Balance between the toxicity and anticancer activity of arsenic trioxide in treatment of acute promyelocytic leukemia

Arsenic trioxide (ATO) has a long history and it is recognized as both poison and drug for more than two thousand years. Since the establishment of ATO as a frontline therapeutic agent for acute promyelocytic leukemia (APL), the survival of APL patients have been greatly improved and APL is turned from highly fatal to highly curable disease. Mechanistically, ATO can induce PML/RARα fusion protein degradation, causing APL cell differentiation and apoptosis. On the other hand, the side effects such as differentiation syndrome, cardiac conduction abnormalities and liver toxicity are often observed during the ATO treatment of APL in clinic. It is likely that the therapeutic and adverse effects of ATO is probably associated with its distinct pattern of metabolism and direct or indirect effects on different organs. In this review, we provided a comprehensive and in-depth elaboration of the cytotoxic mechanisms of ATO and its methylated metabolites based on in vivo or in vitro studies, trying to clarify the importance of achieving balance between the toxicity and anti-leukemic activity of ATO in APL treatment.

Abstract 606: Cisplatin disrupts MDM2-DAXX-HAUSP complex, &amp; induces apoptosis in acute leukemia cells

Abstract Cisplatin (CDDP) is an antitumor drug successfully used in the treatment of various types of human malignancies. It enhances toxicity of arsenic trioxide (ATO) in head and neck squamous cell carcinoma cell, small cell lung cancer, ovarian cancer cells, and oral squamous cell carcinoma cells (, and chronic myelogenous leukemia cells. CDDP induces cytotoxicity, DNA damage, oxidative stress, and apoptosis in acute promyelocytes leukemia (APL) cells. However, the molecular mechanisms of CDDP-induced P53 activation, cell cycle arrest, and apoptosis in APL cells remain poorly understood. We hypothesized that CDDP inhibits proliferation of APL cells through MDM2-DAXX-HAUSP complex disruption, p53 activation leading to cell cycle arrest and apoptosis. To test hypothesis, we used three APL cell lines and a mice model of APL and investigated CDDP effects on cells growth, complex disruption, cell cycle progression, and apoptosis by applying western blotting, immunoprecipitation(IP), gene knockdown techniques, immune/histocytochemistry, and confocal imaging. We found that CDDP induced stress signal transmitted by protein kinase (ATM, ATR) and its downstream targets (CHK1 &amp; CHK2) phosphorylation leading to down-regulation of complex molecules expression and accumulation of p53. CDDP-induced p53 expression modulated cell cycle progression and apoptosis in APL cells, and stimulated the formation of more promyelocytes with dense granules through reduction of MDM2 expression in bone marrow cells. CDDP also activated p53 in APL mice liver tissues. This novel mechanism of action of CDDP in APL cells may help in the design of new anti-leukemic drugs for treatment of APL patients. Citation Format: Paul B. Tchounwou, Sanjay Kumar. Cisplatin disrupts MDM2-DAXX-HAUSP complex, &amp; induces apoptosis in acute leukemia cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 606.

Synergy between parthenolide and arsenic trioxide in adult T-cell leukemia/lymphoma cells in vitro.

Objective(s):Adult T-cell leukemia/lymphoma (ATLL) is an aggressive lymphoid malignancy with low survival rate and distinct geographical distribution. In search for novel chemotherapeutics against ATLL, we investigated the combinatorial effects of parthenolide, a sesquiterpene lactone with valuable pharmaceutical activities, and arsenic trioxide (ATO) in vitro. Materials and Methods:MT2 cells, an ATLL cell line, were treated with increasing concentrations of parthenolide (1.25, 2.5, and 5 μg/ml) and ATO (2, 4, 8, and 16 µM) to determine their IC50. Then, cells were treated with a combination of sub-IC50 concentrations of parthenolide (1 μg/ml) and ATO (2 µM) for 72 hr. Cell viability and cell cycle changes were assessed by Alamar blue and PI staining, respectively. To understand the mechanisms responsible for observed effects, expression of CD44, NF-κB (REL-A), BMI-1, and C-MYC were investigated by real-time PCR.Results:Assessment of cell viability indicated that parthenolide significantly increased the toxicity of ATO, as confirmed by accumulation of MT2 cells in the sub G1 phase of the cell cycle. Moreover, molecular analysis revealed significant down-regulation of CD44, NF-κB (REL-A), BMI-1, and C-MYC upon combinatorial administration of parthenolide and ATO in comparison with relevant controls.Conclusion:Taken together, present results showed that parthenolide significantly enhanced the toxicity of ATO in MT2 cells. Therefore, the future possible clinical impact of our study could be combinatorial use of parthenolide and ATO as a novel and more effective approach for ATLL.

Preliminary study of Realgar and arsenic trioxide on gut microbiota of mice

The aim of this paper was to observe the effect of Realgar and arsenic trioxide on gut microbiota. The mice were divided into low-dose Realgar group(RL), medium-dose Realgar group(RM), high-dose Realgar group(RH), and arsenic trioxide group(ATO), in which ATO and RL groups had the same trivalent arsenic content. Realgar and arsenic trioxide toxicity models were established after intragastric administration for 1 week, and mice feces were collected 1 h after intragastric administration on day 8. The effects of Realgar on gut microbiota of mice were observed through bacterial 16 S rRNA gene sequences. The results showed that Lactobacillus was decreased in all groups, while Ruminococcus and Adlercreutzia were increased. The RL group and ATO group were consistent in the genera of Prevotella, Ruminococcus, and Adlercreutzia but different in the genera of Lactobacillus and Bacteroides. Therefore, the effects of Realgar and arsenic trioxide with the same amount of trivalent arsenic on gut microbiota were similar, but differences were still present. Protective bacteria such as Lactobacillus were reduced after Realgar administration, causing inflammation. At low doses, the number of anti-inflammatory bacteria, such as Ruminococcus, Adlercreutzia and Parabacteroides increased, which can offset the slight inflammation caused by the imbalance of bacterial flora. At high doses, the flora was disturbed and the number of Proteobacteria was increased, with aggravated intestinal inflammation, causing edema and other inflammatory reactions. Based on this, authors believe that the gastrointestinal reactions after clinical use of Realgar may be related to flora disorder. Realgar should be used at a small dose in combination with other drugs to reduce intestinal inflammation.

Erythrocyte Membrane-Coated Arsenic Trioxide-Loaded Sodium Alginate Nanoparticles for Tumor Therapy.

Arsenic trioxide (ATO) has a significant effect on the treatment of acute promyelocytic leukemia (APL) and advanced primary liver cancer, but it still faces severe side effects. Considering these problems, red blood cell membrane-camouflaged ATO-loaded sodium alginate nanoparticles (RBCM-SA-ATO-NPs, RSANs) were developed to relieve the toxicity of ATO while maintaining its efficacy. ATO-loaded sodium alginate nanoparticles (SA-ATO-NPs, SANs) were prepared by the ion crosslinking method, and then RBCM was extruded onto the surface to obtain RSANs. The average particle size of RSANs was found to be 163.2 nm with a complete shell-core bilayer structure, and the average encapsulation efficiency was 14.31%. Compared with SANs, RAW 264.7 macrophages reduced the phagocytosis of RSANs by 51%, and the in vitro cumulative release rate of RSANs was 95% at 84 h, which revealed a prominent sustained release. Furthermore, it demonstrated that RSANs had lower cytotoxicity as compared to normal 293 cells and exhibited anti-tumor effects on both NB4 cells and 7721 cells. In vivo studies further showed that ATO could cause mild lesions of main organs while RSANs could reduce the toxicity and improve the anti-tumor effects. In brief, the developed RSANs system provides a promising alternative for ATO treatment safely and effectively.