Toxic Injury Research Articles

RADT-48. ANALYSIS OF PROTON RADIATION THERAPY INDUCED CONTRAST ENHANCEMENT: A SINGLE INSTITUTION, RETROSPECTIVE STUDY

Abstract Proton radiotherapy (PRT) has superior physical dose distribution with a lesser integral off target radiation dose exposure compared with standard photon radiotherapy resulting in reduced toxicity of uninvolved normal tissues. However, there may be toxicity in areas targeted for high dose treatment as a result of uncertainty about the relative radiobiologic effect (RBE) of proton radiotherapy compared with photon radiotherapy and the potential for localized high doses at the end of the proton beam range (Bragg peak). This may result in radiation-induced contrast enhancement (RICE) reflecting transient toxicity or permanent injury, particularly when associated with concurrent chemotherapy. We analyzed 150 consecutive adult patients, with a histopathologic diagnosis of CNS malignancy, who underwent only PRT at Johns Hopkins Hospital between 2019 – 2023 with least 1 year of follow-up imaging. RICE was defined as a new post-treatment contrast enhancement on MRI within the radiation field. The determination of disease progression or RICE was confirmed with additional follow-up MRI or pathology. RICE was identified in 14 cases (9.3%). The median age was 48 y (range 19 – 72 years), sex 50% female. Diagnosis was 5 astrocytoma, 3 meningioma, 2 glioblastoma, 1 medulloblastoma, 2 oligodendroglioma, 1 tectal glioma. 4/5 astrocytoma patients were grade 2, 2/3 meningioma was grade 1, 1/3 was grade 2, 2/2 oligodendroglioma was grade 2. The median time since completing PRT to development of RICE was 3.5 months. The median radiation dose was 52.20 Gye (range 23.40 - 60.06). Dexamethasone was used in 11 patients (78 %) and in bevacizumab was used 2. Chemotherapy with temozolomide 7 (50%), PCV 1, and none in 5. 12 (85%) patients were still alive. PRT can also be associated with radiation injury in the target, and more information is needed about the incidence, natural history, and associations with localized dosimetry.

Morphological Changes in the Brain During Toxic Injury

Toxic damage to various tissues of the body is accompanied by dystrophic and necrotic processes. The nervous system is most susceptible to the influence of exogenous substances both of a chemical and biological nature. Dystrophy is a complex pathological process, which is based on a violation of cell nutrition, leading to age-related and structural changes, as well as neurodegeneration. In toxic lesions, cell death can occur through either necrosis or apoptosis.

Baclofen-related deaths in Australia 2000–2022

In Australia, the therapeutic indication of baclofen (oral tablets) is for the treatment of muscle spasm. Deaths related to baclofen have been reported, as well as misuse, dependence and self-poisoning. This national retrospective study aimed to investigate the number, characteristics, circumstances, and toxicology of baclofen-related deaths in Australia, 2000–2022. We identified 102 baclofen-related deaths, with a mean age of 45.6 years and 51 % being male. Circumstances of death were: intentional toxicity (54.9 %), unintentional toxicity (30.4 %), unintentional toxicity/disease (9.8 %), and accidental injury (4.9 %). Multiple sclerosis or spinal injury was documented in 15.7 % of cases, substance use problems in 43.1 % and specifically alcohol use problems in 38.2 %. Mental health problems were documented in 73.5 %, a previous self-harm or suicide attempt in 30.4 %, and chronic pain in 37.3 %. The median baclofen blood concentration for all cases was 3.10 mg/L (25th 0.70, 75th 8.10, range 0.04–110.00), unintentional toxicity 1.95 mg/L (25th 0.70, 75th 4.35, range 0.04–24.0), intentional toxicity 6.00 mg/L (25th 1.10, 75th 13.0, range 0.05–110.0). Concomitant substance use was seen in 93.8 %, with antidepressants (69.8 %) and benzodiazepines (64.6 %) most frequently detected. In conclusion, the ‘typical’ case was middle-aged, most dying due to intentional toxicity, and likely to have a history of mental health and substance use problems. We suggest caution is needed in prescribing baclofen given its potential to be used in intentional and non-intentional overdose.

Regeneration of zebrafish retina following toxic injury

The structure of the zebrafish retina appears to be very similar to that of mammals, that is why it is used as a model for studying the eye. Indeed, the zebrafish retina can regenerate itself through mechanisms of Müller cell reprogramming. In this research, adult zebrafish were exposed to aluminum to cause damage in the retina and thus evaluate the regenerative capacity of the damaged tissue. Histological and histochemical analyses assessed the retinal structure and the neurodegenerative process, respectively. An expression analysis of PARPs was carried out to verify whether a potential oxidative DNA damage happens. In addition, some genes involved in the regeneration process (pax6a, pax2a, ngn1, and notch1a) were analyzed. The data confirmed the toxicity of aluminum which caused retinal neurodegeneration, but also highlighted the ability of zebrafish to regenerate the retinal structure, repairing the damage and confirming its use as a good model for translational studies.

One case of comprehensive treatment of acute severe ammonia-induced intoxication with extracorporeal membrane oxygenation

Acute ammonia-induced intoxication is a kind of acute irritant gas poisoning, which mainly causes systemic inflammatory reaction and immune dysfunction through direct and indirect lung injury, leading to chemogenic pulmonary edema and acute respiratory distress syndrome (ARDS). The mechanism of its toxic injury is complex, and the fatality rate of patients increases significantly once ARDS occurs. In this paper, the patient with acute and severe ammonia-induced intoxication was successfully treated by extracorporeal membrane oxygenation (ECMO) combined with fiberoptic bronchoscopy and other critical technologies, and achieved good results. By analyzing the diagnosis and treatment process of severe ammonia-induced intoxication complicated with ARDS patients, this paper summarizes the clinical characteristics of ammonia-induced intoxication injury, and the application opportunities of ECMO and various critical medical technologies, so as to facilitate the efficient intervention and treatment of ammonia-induced intoxication according to the clinical opportunity and improve the survival rate of patients.

Toxic and Metabolic Kidney Injury: Focus on Energy Drinks

Currently, energy drinks on the market are represented by medium and highly carbonated, as well as non-alcoholic and low-alcohol products. More than 500 brands producing energy drinks are registered in the world. Long-term abuse of energy drinks can lead to serious consequences. Kidney damage caused by energy drinks is becoming an urgent medical and social problem, since with prolonged use there is dependence on them, numbness of the limbs, palpitations, headaches and dizziness, pain in the precordial region, increased blood clotting, frequent urination, irritability, depression, insomnia, increased fatigue, anxiety, fear and convulsions. Widespread and uncontrolled use of energy drinks can cause social imbalance in society, decreased mental and physical performance, especially in adolescents. The toxic properties of energy drinks are manifested depending on the volume and composition, presentation, duration of intake, as well as concomitant disease. Availability, wide popularization through advertising in the media, insufficient awareness of young people about the harmful effects of energy drinks serves as a condition for the development of damage to internal organs when consuming them. The article presents data from scientific literature on the epidemiology of risk factors for the development and progression of chronic renal failure. Negative effects on human health with long-term abuse of energy drinks are discussed. The article presents the results of clinical observation of patient N., 31 years old, who developed a neo-oliguric variant of acute kidney injury against the background of long-term use of energy drinks. Laboratory testing revealed hyperglycemia, dyslipidemia, hypercreatininemia (blood creatinine 161.0 μmol/l) and hypercytokinemia due to an increase in the serum concentration of interleukin-6. The glomerular filtration rate (GFR) was at the level of 48 ml/min. Against the background of the therapy, kidney function was restored: blood creatinine 85.9 μmol/l, GFR increased to 116 ml/min.

Hepatoprotective and metabiotic correction and its effect on the content of free fatty acid in rats with experimental toxic liver injury

Hepatoprotective and metabiotic correction and its effect on the content of free fatty acid in rats with experimental toxic liver injury

Caffeine: The Story beyond Oxygen-Induced Lung and Brain Injury in Neonatal Animal Models-A Narrative Review.

Caffeine is one of the most commonly used drugs in intensive care to stimulate the respiratory control mechanisms of very preterm infants. Respiratory instability, due to the degree of immaturity at birth, results in apnea of prematurity (AOP), hyperoxic, hypoxic, and intermittent hypoxic episodes. Oxidative stress cannot be avoided as a direct reaction and leads to neurological developmental deficits and even a higher prevalence of respiratory diseases in the further development of premature infants. Due to the proven antioxidant effect of caffeine in early use, largely protective effects on clinical outcomes can be observed. This is also impressively observed in experimental studies of caffeine application in oxidative stress-adapted rodent models of damage to the developing brain and lungs. However, caffeine shows undesirable effects outside these oxygen toxicity injury models. This review shows the effects of caffeine in hyperoxic, hypoxic/hypoxic-ischemic, and intermittent hypoxic rodent injury models, but also the negative effects on the rodent organism when caffeine is administered without exogenous oxidative stress. The narrative analysis of caffeine benefits in cerebral and pulmonary preterm infant models supports protective caffeine use but should be given critical consideration when considering caffeine treatment beyond the recommended corrected gestational age.

Effects of vitrification on mitochondrial ultrastructure and membrane potential and its distribution in mouse oocytes

BACKGROUND: Vitrification is commonly used for in vitro fertilization and has significant impact on gametes. OBJECTIVE: To investigate changes in ultrastructure, membrane potential (ΔΨm) and distribution of mitochondria in mouse oocytes after vitrification.MATERIALS AND METHODS: Mouse oocytes were divided into three groups: one group as fresh control, one group for the toxicity test (treated with cryoprotectant but without vitrification), and the other for vitrification. RESULTS: Most mitochondria in oocytes were damaged after cooling and warming, being rough and fuzzy in appearance, even swollen and broken. The ΔΨm of the toxicity test group and the vitrification group was 0.320±0.030 and 0.244±0.038, respectively, in comparison to the fresh group (0.398±0.043). The ΔΨm of the vitrified oocytes was significantly lower than fresh oocytes and the toxicity test oocytes (P<0.05), but there was no significant difference between fresh oocytes and the toxicity test oocytes (P>0.05). Mitochondria in fresh oocytes were denser and strained stronger, with 59.5% distributed homogeneously and 36.4% polarized. The majority of mitochondria in the toxicity-tested oocytes were clustered (69.3%) and only a small portion were distributed homogeneously (19.6%), while mitochondria in vitrified oocytes were clustered (56.3%) and deficient (24.4%), and their fluorescent staining was weak and blurred. There was a significant disruption in mitochondrial function after vitrification. CONCLUSION: Vitrification alters the ultrastructure, membrane potential and distribution of mitochondria in oocytes, most likely caused by toxicity and mechanical injury.

LIFR regulates cholesterol-driven bidirectional hepatocyte-neutrophil cross-talk to promote liver regeneration.

Liver regeneration is under metabolic and immune regulation. Despite increasing recognition of the involvement of neutrophils in regeneration, it is unclear how the liver signals to the bone marrow to release neutrophils after injury and how reparative neutrophils signal to hepatocytes to reenter the cell cycle. Here we report that loss of the liver tumour suppressor Lifr in mouse hepatocytes impairs, whereas overexpression of leukaemia inhibitory factor receptor (LIFR) promotes liver repair and regeneration after partial hepatectomy or toxic injury. In response to physical or chemical damage to the liver, LIFR from hepatocytes promotes the secretion of cholesterol and CXCL1 in a STAT3-dependent manner, leading to the efflux of bone marrow neutrophils to the circulation and damaged liver. Cholesterol, via its receptor ERRα, stimulates neutrophils to secrete hepatocyte growth factor to accelerate hepatocyte proliferation. Altogether, our findings reveal a LIFR-STAT3-CXCL1-CXCR2 axis and a LIFR-STAT3-cholesterol-ERRα-hepatocyte growth factor axis that form bidirectional hepatocyte-neutrophil cross-talk to repair and regenerate the liver.

Cysteine triggered cascade reaction forming coumarin: Visualization of cysteine fluctuation in alcoholic liver disease by a NIR fluorescent probe

Alcoholic liver disease (ALD) is a chronic toxic liver injury caused by long-term heavy drinking. Due to the increasing incidence, ALD is becoming one of important medical tasks. Many studies have shown that the main mechanism of liver damage caused by large amounts of alcohol may be related to antioxidant stress. As an important antioxidant, cysteine (Cys) is involved in maintaining the normal redox balance and detoxifying metabolic function of the liver, which may be closely related to the pathogenesis of ALD. Therefore, it is necessary to develop a simple non-invasive method for rapid monitoring of Cys in liver. Thus, a near-infrared (NIR) fluorescent probe DCI-Ac-Cys which undergoes Cys triggered cascade reaction to form coumarin fluorophore is developed. Using the DCI-Ac-Cys, decreased Cys was observed in the liver of ALD mice. Importantly, different levels of Cys were monitored in the livers of ALD mice taking silybin and curcumin with the antioxidant effects, indicating the excellent therapeutic effect on ALD. This study provides the important references for the accurate diagnosis of ALD and the pharmacodynamic evaluation of silybin and curcumin in the treatment of ALD, and support new ideas for the pathogenesis of ALD.

Research on the damage and wound repair of cornea by GO and ZnO

Objective The widespread use of nanoparticles in recent years has increased the risk of ocular exposure. zinc oxide (ZnO) is widely used in the field of cosmetics because of its unique chemical properties. The application of graphene oxide (GO) as an emerging nanomaterial in the field of eye drops is also gradually emerging. Currently, research on ZnO and GO eye exposure mainly focuses on application or toxicity to optic nerve cells. There’s less study on corneal wound healing effects. and the previous research hasn’t compared ZnO and GO corneal toxicity. Methods We systematically established a complete chain study of in vitro and in vivo experiments and mouse corneal injury model, and comprehensively evaluated the ocular safety and toxicity of ZnO and GO. Results We found that 50 ug/mL GO and 0.5 ug/mL ZnO can reduce human corneal epithelial cells (HCEpiC) viability in a concentration-dependent manner. Short-term repeated exposure to ZnO can cause sterile inflammation of the cornea with concentration-dependence, while GO have not been significantly altered. 50 ug/mL ZnO could significantly delay the healing of corneal wounds, while GO did not change wound healing. Conclusion The toxic effect of ZnO is higher than that of GO. Inflammatory signal transduction, oxidative stress and apopnano zitosis are involved in the ocular toxicity injury process of nanoparticles. Research can provide a judgement basis for people’s eye health and eye protection risk control.

Cryopreservation of Immune Cells: Recent Progress and Challenges Ahead.

Cryopreservation of immune cells is considered as a key enabling technology for adoptive cellular immunotherapy. However, current immune cell cryopreservation technologies face the challenges with poor biocompatibility of cryoprotection materials, low efficiency, and impaired post-thaw function, limiting their clinical translation. This review briefly introduces the adoptive cellular immunotherapy and the approved immune cell-based products, which involve T cells, natural killer cells and etc. The cryodamage mechanisms to these immune cells during cryopreservation process are described, including ice formation related mechanical and osmotic injuries, cryoprotectant induced toxic injuries, and other biochemical injuries. Meanwhile, the recent advances in the cryopreservation medium and freeze-thaw protocol for several representative immune cell type are summarized. Furthermore, the remaining challenges regarding on the cryoprotection materials, freeze-thaw protocol, and post-thaw functionality evaluation of current cryopreservation technologies are discussed. Finally, the future perspectives are proposed toward advancing highly efficient cryopreservation of immune cells.

Acute-on-chronic liver failure in metabolic dysfunction-associated fatty liver disease patients: a disease multiplier.

Acute-on-chronic liver failure (ACLF) is a syndrome of liver failure due to an acute hepatic insult leading to liver failure with or without extra-hepatic organ failure in a patient of chronic liver disease (CLD) with or without cirrhosis presenting for the first time. The definition is still with controversy; hence, homogeneity and clarity of the case is an unmet need. There is a paradigm shift noted as far as the etiology of CLD is concerned with rise in metabolic dysfunction-associated fatty liver disease (MAFLD) and ethanol as the dominant cause even in developing countries. MAFLD is the change in nomenclature from NAFLD to justify the metabolic derangement in these group of patients. The shift from an exclusion-based criteria to one that has evolved to a diagnosis that requires positive criteria has profound significance. Clearly there is a difference in terms of its prevalence, disease progression, and liver-related events, as well as management of metabolic risk factors and MAFLD itself which requires further understanding. In tandem with the global rise in MAFLD, the incidence of MAFLD-ACLF is increasing. Excessive alcohol consumption causes metabolic and toxic injury to the liver resulting in nearly similar pathway of fatty liver, hepatitis, and cirrhosis. The interaction of MAFLD as an additional underlying chronic liver injury in ACLF patients is complex due to the presence of metabolic risk factors that are unique to MAFLD. There is lack of clarity on how MAFLD affects the clinical course of ACLF due to scarcity of this specific data. This narrative review aims to understand the unique effects, consequences, and management of MAFLD as the chronic liver injury component in ACLF.

AGE-DEPENDENCE OF BIOCHEMICAL MANIFESTATIONS OF HEPATOTOXICINJURY IN RAT EXPOSED TO XENOBIOTICS OF VARIOUS GENESIS

Currently, the problem of liver diseases against the backdrop of the toxic effects of medicinal and industrial (herbicides) xenobiotics on the body is becoming increasingly relevant. The activation of compensatory mechanisms in response to the action of toxic agents –acetaminophen and/or diquat is closely related to age-specific features. Heightened focus on acetaminophen-induced injury is linked to the widespread use of this medication as an analgesic and antipyretic during pandemics of infectious and inflammatory diseases, especially under the conditions of warfare in Ukraine. In return, the widespread use of the herbicide diquat is accompanied by an increase in the registration of cases of diquat -induced acute poisoning. The aim of study was to evaluation the biochemical parameters of the functional state of the liver of different-aged rats under conditions of acetaminophen-and diquat-induced toxic injury. Animals were divided into three age groups: adolescent (60 days), reproductive (150 days), and mature age rats (360 days). Acute toxic injury by acetaminophen was modeled by its oral administration through gastric intubation at a daily dose of 1250 mg/kg of the animal's body weight during the last 2 days of the experiment. Acute toxic damage by diquat was modeled by a single intragastric administration using a probe at a dose of 115.5 mg/kg of the animal's body weight. The functional state of the liver was assessed on an automatic biochemical analyzer NTI Biochem FC-120.Acetaminophen intoxication led to an increase in the absolute liver mass indicator, organ index, changes in the macroscopic structure of the organ, increased serum activities of ALT and AST, total LDH, and a decrease in the De Ritis ratio amidst increased activities of ALP, GGT, and levels of total and indirect bilirubin in all age groups compared to the control. The most significant changes were observed in mature age animals (increase in ALT activity by 76%, AST by 56%, ALP by 51%, GGT by 51%, and a decrease in the De Ritis ratio by 47%). Under conditionsof diquat-induced toxic injury, a slightly different trend and degree in manifestation of established changes are observed. A more pronounced hepatotoxic effect was registered in adolescent animals, manifested by the maximum increase in absolute liver mass by 26%, ALT activity by 71%, AST by 47%, ALP by 50%, Bili-T level by 69%. No statistically significant differences compared to the control and APAP-induced injury in the activity of total LDH and GGT upon administration of toxic doses of the herbicide diquat regardless of age category were observed.Based on the experimental results, an age-related multidirectionality in the adverse effects of the medicinal xenobiotic acetaminophen and the industrial xenobiotic diquat on indicators of the morpho-functional state of the liver is observed. The most sensitive age group of animals to toxic injury by acetaminophen are rats of 360 days of age, while for diquat –60 days of age

Research progress on the correlation between cataract occurrence and nutrition.

Cataract is a common eye disease characterized by lens opacity, leading to blurred vision and progressive blindness of the eye. Factors affecting the development of cataracts include nutrition, oxidative stress, micronutrients and inflammatory factors, and also include genetics, toxicity, infrared exposure, hyperuricemia, and mechanical injuries. Among the nutritional factors, a balanced diet, vegetarian diet, dairy products and vegetables are protective against cataracts; high-sodium diet, high intake of carbohydrates and polyunsaturated fatty acids may increase the risk of cataracts; and increased intake of proteins, especially animal proteins, may prevent nuclear cataracts. Intake of antioxidants such as β-carotene, lutein, or zeaxanthin is associated with a reduced risk of cataracts. Minerals such as zinc, selenium, calcium and sodium have also been associated with cataract development. Oxidative stress plays an important role in the development of cataracts and is associated with several antioxidative enzymes and biomarkers such as glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE). Insulin resistance is also an essential risk factor for cataracts, especially in diabetic patients. In conclusion, understanding these influencing factors helps us to better prevent cataracts. And in this article, we will focus on the important factor of diet and nutrition for a detailed discussion.

Study on the mechanism of hepatotoxicity of Aucklandiae radix through liver metabolomics and network pharmacology.

Aucklandiae Radix (CAR) and its roasted processed products (PAR) are extensively used in various Chinese patent medicines due to their diverse pharmacological activities. However, numerous side effects of CAR have been reported and the hepatotoxicity and the corresponding mechanisms have not been thoroughly investigated. Our study aims to explore the underlying mechanism of the hepatotoxic impacts of CAR. In this study, metabolomic analysis was performed using liver tissue from the mice administered with different dosages of CAR/PAR extracts to examine the hepatotoxic impacts of CAR and elucidate the underlying mechanism. Network pharmacology was employed to predict the potential molecular targets and associated signaling pathways based on the distinctive compounds between CAR and PAR. A composition-target-GO-Bio process-metabolic pathway network was constructed by integrating the hepatotoxicity-related metabolic pathways. Finally, the target proteins related with the hepatotoxic effect of CAR were identified and validated in vivo. The metabolomics analysis revealed that 33 related metabolic pathways were significantly altered in the high-dose CAR group, four of which were associated with the hepatotoxicity and could be alleviated by PAR. The network identified NQO1 as the primary target of the hepatotoxic effect induced by CAR exposure, which was subsequently verified by Western Blotting. Further evidence in vivo demonstrated that Nrf2 and HO-1, closely related to NQO1, were also the main targets through which CAR induced the liver injury, and that oxidative stress should be the primary mechanism for the CAR-induced hepatotoxicity. This preliminary study on the hepatic toxic injury of CAR provides a theoretical basis for the rational and safe use of CAR rationally and safely in clinical settings.

Cardiomyocyte-specific overexpression of FPN1 diminishes cardiac hypertrophy induced by chronic intermittent hypoxia.

The significance of iron in myocardial mitochondria function cannot be underestimated, because deviations in iron levels within cardiomyocytes may have profound detrimental effects on cardiac function. In this study, we investigated the effects of ferroportin 1 (FPN1) on cardiac iron levels and pathological alterations in mice subjected to chronic intermittent hypoxia (CIH). The cTNT-FPN1 plasmid was administered via tail vein injection to induce the mouse with FPN1 overexpression in the cardiomyocytes. CIH was established by exposing the mice to cycles of 21%-5% FiO2 for 3 min, 8 h per day. Subsequently, the introduction of hepcidin resulted in a reduction in FPN1 expression, and H9C2 cells were used to establish an IH model to further elucidate the role of FPN1. First, FPN1 overexpression ameliorated CIH-induced cardiac dysfunction, myocardial hypertrophy, mitochondrial damage and apoptosis. Second, FPN1 overexpression attenuated ROS levels during CIH. In addition, FPN1 overexpression mitigated CIH-induced cardiac iron accumulation. Moreover, the administration of hepcidin resulted in a reduction in FPN1 levels, further accelerating the CIH-induced levels of ROS, LIP and apoptosis in H9C2 cells. These findings indicate that the overexpression of FPN1 in cardiomyocytes inhibits CIH-induced cardiac iron accumulation, subsequently reducing ROS levels and mitigating mitochondrial damage. Conversely, the administration of hepcidin suppressed FPN1 expression and worsened cardiomyocyte iron toxicity injury.

BI-2865, a pan-KRAS inhibitor, reverses the P-glycoprotein induced multidrug resistance in vitro and in vivo

BackgroundMultidrug resistance (MDR) limits successful cancer chemotherapy. P-glycoprotein (P-gp), BCRP and MRP1 are the key triggers of MDR. Unfortunately, no MDR modulator was approved by FDA to date. Here, we will investigate the effect of BI-2865, a pan-KRAS inhibitor, on reversing MDR induced by P-gp, BCRP and MRP1 in vitro and in vivo, and its reversal mechanisms will be explored.MethodsThe cytotoxicity of BI-2865 and its MDR removal effect in vitro were tested by MTT assays, and the corresponding reversal function in vivo was assessed through the P-gp mediated KBv200 xenografts in mice. BI-2865 induced alterations of drug discharge and reservation in cells were estimated by experiments of Flow cytometry with fluorescent doxorubicin, and the chemo-drug accumulation in xenografts’ tumor were analyzed through LC-MS. Mechanisms of BI-2865 inhibiting P-gp substrate’s efflux were analyzed through the vanadate-sensitive ATPase assay, [125I]-IAAP-photolabeling assay and computer molecular docking. The effects of BI-2865 on P-gp expression and KRAS-downstream signaling were detected via Western blotting, Flow cytometry and/or qRT-PCR. Subcellular localization of P-gp was visualized by Immunofluorescence.ResultsWe found BI-2865 notably fortified response of P-gp-driven MDR cancer cells to the administration of chemo-drugs including paclitaxel, vincristine and doxorubicin, while such an effect was not observed in their parental sensitive cells and BCRP or MRP1-driven MDR cells. Importantly, the mice vivo combination study has verified that BI-2865 effectively improved the anti-tumor action of paclitaxel without toxic injury. In mechanism, BI-2865 prompted doxorubicin accumulating in carcinoma cells by directly blocking the efflux function of P-gp, which more specifically, was achieved by BI-2865 competitively binding to the drug-binding sites of P-gp. What’s more, at the effective MDR reversal concentrations, BI-2865 neither varied the expression and location of P-gp nor reduced its downstream AKT or ERK1/2 signaling activity.ConclusionsThis study uncovered a new application of BI-2865 as a MDR modulator, which might be used to effectively, safely and specifically improve chemotherapeutic efficacy in the clinical P-gp mediated MDR refractory cancers.

Novel mechanistic insights into Cr(VI) and Cr(III) induced discrepancies of cellular toxicity and oxidative injury events in Eisenia fetida

Chromium (Cr) poses a high ecological risk, however the toxic mechanisms of Cr in different valence states to soil organisms at cellular and molecular levels are not exactly. In this study, the Eisenia fetida coelomocytes and Cu/Zn-superoxide dismutase (Cu/Zn-SOD) were chosen as the target subjects to investigate the effects and mechanisms of cellular toxicity induced by Cr(VI) and Cr(III). Results indicated that Cr(VI) and Cr(III) significantly reduced the coelomocytes viability. The level of reactive oxygen species (ROS) was markedly increased after Cr(VI) exposure, which finally reduced antioxidant defense abilities, and induced lipid peroxidation and cellular membrane damage in earthworm coelomocytes. However, Cr(III) induced lower levels of oxidative stress and cellular damage with respect to Cr(VI). From a molecular perspective, the binding of both Cr(VI) and Cr(III) with Cu/Zn-SOD resulted in protein backbone loosening and reduced β-Sheet content. The Cu/Zn-SOD showed fluorescence enhancement with Cr(III), whereas Cr(VI) had no obvious effect. The activity of Cu/Zn-SOD continued to decrease with the exposure of Cr. Molecular docking indicated that Cr(III) interacted more readily with the active center of Cu/Zn-SOD. Our results illustrate that oxidative stress induced by Cr(VI) and Cr(III) plays an important role in the cytotoxic differences of Eisenia fetida coelomocytes and the binding of Cr with Cu/Zn-SOD can also affect the normal structures and functions of antioxidant defense-associated protein.