Reversal of multidrug resistance by 5,5'-dimethoxylariciresinol-4-O-β-D-glucoside in doxorubicin-resistant human leukemia K562/DOX

Hesperetin-Based Hydrogels Protect the Skin against UV Radiation-Induced Damage

UV radiation can cause damages, such as erythema, skin photoaging, and carcinogenesis. The adoption of protective measures against sun exposure is essential to prevent these damages, and the interest in using natural substances as an alternative for photoprotection is growing. Thus, hesperetin with antioxidant, anti-inflammatory, and anticancer properties is a promising substance to be used with photochemopreventive action and to protect the skin from damage induced by UV radiation. Therefore, the present study aimed to develop a topical formulation based on AAMVPC gel containing hesperetin and evaluate its photoprotective effect on the skin of rats exposed to UVA-UVB radiation. The animals were submitted to the irradiation protocol UVA-UVB, and at the end, erythema, lipid peroxidation, and activity of the antioxidant enzyme catalase and superoxide dismutase were evaluated. Additionally, it evaluated the activity of myeloperoxidase and histological changes. The formulation presented a rheological and spreadability profile suitable for cutaneous application. In vivo results demonstrated that the topical formulation of AAMVPC gel containing hesperetin at a concentration of 10% protected the skin from damage induced by UVA-UVB radiation, with the absence of erythema, lipid lipoperoxidation, and inflammation (low myeloperoxidase activity), and increased catalase and superoxide dismutase activities. The morphology and architecture of the dermo-epidermal tissue of these animals were like those observed under normal conditions (non-irradiated animals). Thus, the results showed that hesperetin was able to protect the animals' skin against UV radiation-induced skin damage and the protection mechanisms may be related to the antioxidant and anti-inflammatory properties of this natural product.

Modulatory efficacy of Punica granatum L. powder ethanol extract (PLEE) on lead acetate-induced hepatic and renal toxicity

Background

Pomegranate powder derived from pomegranate fruit contains phytochemicals chief of which is ellagitannins. Owing to their high antioxidative capabilities we investigated its efficacy against lead acetate induced hepatic and renal toxicity.

Methods

Pomegranate powder (500 g) was procured and soaked in 1 Litre of ethanol for three days, its filtrate was concentrated and freeze dried to form Punica granatum L. ethanol extract (PLEE). Thirty (30) male albino Wistar rats with average weight between 140 ± 20 g were used for this study. They were equally shared into 6 groups with 5 animals each; A: Control; B: Lead acetate only C: Lead acetate + PLEE (1); D: Lead acetate + PLEE (2); E: PLEE (1) and F: PLEE (2). Serum, liver and kidney samples were obtained for biochemical assays. The integrity of liver and kidney tissues were also accessed.

Results

Lead administration resulted in marked elevations in liver transaminases in serum and liver as well as a significant increase in kidney function markers in the serum and kidney (p < 0.05). There was also a significant decline in average body weight, antioxidant markers in the liver and kidney of Wistar rats while there was a significant increase in lipid peroxidation levels in both liver and kidney. However, administration of PLEE at different doses significantly modulated these changes.

Conclusion

Lead acetate administration led to hepatic and renal toxicity as evident by alterations in liver and kidney function markers, antioxidant status and tissue integrity. However, PLEE can combat these toxicities.

The effect of diosmin against lead exposure in rats‡

In this study, the effect of diosmin against the adverse effects of lead exposure in rats was investigated. Wistar Albino race 40 male rats weighing 150-200 g 2-3 months were used. A total of 4 groups were assigned, one of which was control and the other 3 were trial groups. The rats in the control group were treated with dimethyl sulfoxide, which was used only as a vehicle in diosmin administration. Groups 2, 3, and 4 from the experimental group were given diosmin at a dose of 50 mg/kg.bw, lead acetate at the dose of 1000 ppm, lead acetate at the dose of 1000 ppm, and diosmin at a dose of 50 mg/kg.bw for 6 weeks, respectively. Application of lead acetate with drinking water and also diosmin was performed by oral catheter. At the end of the experimental period, blood was taken to dry and with heparin by puncture to the heart under light ether anesthesia. Following the blood samples, some organs of the rats (the liver, kidney, brain, heart, and testis) were removed. Some biochemical parameters (glucose, triglyceride, cholesterol, BUN, creatinine, uric acid, LDH, AST, ALT, ALP, total protein, albumin) were measured in serum. Some oxidative stress parameters in tissue samples and blood (MDA, NO, SOD, CAT, GSH-Px, GSH) were evaluated. Body and organ (the liver, kidney, brain, heart, and testis) weights were also evaluated at the end of the study. No significant change was observed in the parameters examined in the diosmin alone-treated group by comparison to control group. On the other hand, significant changes were found in the values ​​of lead acetate-treated group comparing control group. It was observed that the values approached the values of the control group in the combination of lead and diosmin. Exposure to lead acetate at a dose of 1000 ppm for 6 weeks causes organ damage; however the diosmin application at a dose of 50 mg/kg.bw had a positive effect on the regression of tissue damage.

Proteomic tools and new insights for the study of B-cell precursor acute lymphoblastic leukemia

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a hematological malignancy of immature B-cell precursors, affecting children more often than adults. The etiology of BCP-ALL is still unknown, but environmental factors, sex, race or ethnicity, and genomic alterations influence the development of the disease. Tools based on protein detection, such as flow cytometry, mass spectrometry, mass cytometry and reverse phase protein array, represent an opportunity to investigate BCP-ALL pathogenesis and to identify new biomarkers of disease. This review aims to document the recent advancements with respect to applications of proteomic technologies to study mechanisms of leukemogenesis, how this information could be used in the discovery of biological targets, and finally we describe the challenges of application of proteomic tools for the approach of BCP-ALL.

The remedial effect of Thymus vulgaris extract against lead toxicity-induced oxidative stress, hepatorenal damage, immunosuppression, and hematological disorders in rats

The Thymus vulgaris (T. vulgaris) has been used in foods for the flavor, aroma, and preservation and in folk medicines. The objective of the present work was to determine the antioxidant and protective effects of T. vulgaris extract against lead (Pb)-intoxicated rats. A thirty-two male Sprague-Dawley were randomly assigned into 4 equal groups and treated for six weeks as follows: group I (GP-I), served as negative control; GP-II, -III, and -IV received either Pb acetate in drinking water (500 mg/L), T. vulgaris extract (500 mg/kg/day) by oral gavage or Pb acetate with T. vulgaris extract, respectively. Blood samples were collected at the end of the study week 6 to measure the hepatic and renal biochemical markers, complete blood count alongside the serum levels of interleukin (IL)-1β, IL-6, IL-10, tumor necrosis (TNF)-α, and interferon (IFN)-γ. Additionally, liver and kidney tissue specimens were collected for histopathology as well as to measure the antioxidant-reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) alongside the lipid peroxidation marker, malonaldehyde (MDA). The results indicated that Pb toxicity increased the serum levels of IL-1β, IL-6, and TNF-α, whereas IL-10 and IFN-γ were reduced. The results showed disturbed liver and renal functions; increased serum levels of ALT, AST, ALP, total bilirubin, creatinine, and urea; and decreased total protein, albumin, and calcium. The GSH, Gpx, and CAT levels were significantly decreased in the Pb-administrated group, while MDA was increased. However, regarding the hepatorenal markers, those animals treated with T. vulgaris alone did not induce any significant changes. Moreover, the combined treatment with T. vulgaris extract together with Pb showed significant improvement in Pb-induced toxicity in all the tested parameters compared to the negative control group. We investigated the potential protective effects of the medicinal plant T. vulgaris in vivo, since there are no publications that address the potential protective effect of this leaf extract against Pb-induced hepatorenal toxicity. Our studies concluded that the T. vulgaris extract reduces Pb overload in hepatorenal tissues, and that this has a potential immunomodulatory role, antioxidant activity, and a protective effect against Pb toxicity.

Effects and molecular mechanisms of AT1-AA in retinopathy of preeclampsia

Preeclampsia not only seriously endangers maternal and fetal health during pregnancy but may incur many sequelae in postpartum women such as reduced visual acuity. Agonistic autoantibodies to the angiotensin II type I receptor (AT1-AA) is closely associated with preeclampsia. The aim of the present study is to determine whether AT1-AA is associated with retinal impairment during the course of preeclampsia. A preeclampsia model was established by injecting AT1-AA into pregnant rats via the tail vein. Changes in the retinal histological structure were observed. Cell apoptosis and cytokines including reactive oxygen species (ROS), as well as apoptosis-related proteins such as Bcl-2, Bax, and caspase-3 were detected. In addition, flash electroretinograms obtained at different postpartum days were analyzed. Compared with the control group, the retinal structure became edematous and the cell density was reduced significantly in preeclampsia group. The cell apoptosis rate was increased significantly. In addition, the content of ROS, the levels of Bax and caspase-3 in the retina were increased, while the content of Bcl-2 was reduced significantly. Continuous observation of the electroretinograms showed loss of retinal ganglion cells postpartum. The present study demonstrated that AT1-AA induced retinal cell apoptosis by promoting ROS release and activating caspase, suggesting that the increased postpartum susceptibility of preeclamptic women to retinopathy is related to AT1-AA-induced cell apoptosis.

Icariin Attenuates High-cholesterol Diet Induced Atherosclerosis in Rats by Inhibition of Inflammatory Response and p38 MAPK Signaling Pathway

Icariin is a flavonoid isolated from the traditional Chinese herbal medicine Epimedium brevicornum Maxim and has been reported to be effective for the treatment of a variety of cardiovascular diseases. The aim of the present study was to investigate the effect and mechanism of icariin on atherosclerosis (AS) using a high-cholesterol diet (HCD)-induced rat model. Seventy male Wistar rats were divided into five groups: 20 in the control group, 20 in the AS group, 10 in the simvastatin group, 10 in the low-dose icariin group, and 10 in the high-dose icariin group. A HCD and vitamin D3 were administered to establish AS rat model. The five groups of rats received daily intragastric administration of normal saline, simvastatin, or icariin (30 mg/kg/d, 60 mg/kg/d) for 4 weeks. The levels of blood lipids, superoxide dismutase (SOD), and malonaldehyde (MDA) were measured. The mRNA levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were analyzed by real-time RT-PCR, and the serum levels of IL-6 and TNF-α were measured using ELISA kit. In addition, the expression of phosphorylated p38 (p-p38) MAPK was detected by Western blot analysis. The results indicated that AS rat models were successfully constructed. In the AS group, the levels of blood lipids including total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), and MDA were significantly increased, while high-density lipoprotein-cholesterol (HDL-C) and SOD were significantly decreased, compared with those in the control group. However, icariin succeeded in improving these biochemical parameters towards the normal values in the control group. In the simvastatin group and the icariin groups, the serum levels of IL-6 and TNF-α and the related tissue mRNA levels, as well as the expression of p-p38 MAPK, were markedly reduced compared with the AS group. In conclusion, the present study indicated that icariin inhibited the HCD-induced dyslipidemia in rats, the mechanisms may be associated with the anti-inflammation, anti-oxidative stress, and downregulation of p-p38 MAPK by icariin.

Hypoxia promotes chemoresistance in acute lymphoblastic leukemia cell lines by modulating death signaling pathways

BACKGROUND

Several studies show that bone marrow (BM) microenvironment and hypoxia condition can promote the survival of leukemic cells and induce resistance to anti-leukemic drugs. However, the molecular mechanism for chemoresistance by hypoxia is not fully understood.

METHODS

In the present study, we investigated the effect of hypoxia on resistance to two therapies, methotrexate (MTX) and prednisolone (PRD), in two cell models for acute lymphoblastic leukemia (ALL). To look for an implication of hypoxia in chemoresistance, cell viability, total cell density and cell proliferation were analyzed. Survival and death signaling pathways were also screened by "reverse phase protein array" (RPPA) and western blotting experiments conducted on selected proteins to confirm the results.

RESULTS

We found that hypoxia promotes chemoresistance in both ALL cell lines. The induction of drug-resistance by hypoxia was not associated with an increase in total cell density nor an increase in cell proliferation. Using RPPA, we show that chemoresistance induced by hypoxia was mediated through an alteration of cell death signaling pathways. This protective effect of hypoxia seems to occur via a decrease in pro-apoptotic proteins and an increase in anti-apoptotic proteins. The results were confirmed by immunoblotting. Indeed, hypoxia is able to modulate the expression of anti-apoptotic proteins independently of chemotherapy while a pro-apoptotic signal induced by a chemotherapy is not modulated by hypoxia.

CONCLUSIONS

Hypoxia is a factor in leukemia cell resistance and for two conventional chemotherapies modulates cell death signaling pathways without affecting total cell density or cell proliferation.

Ginger extract modulates Pb-induced hepatic oxidative stress and expression of antioxidant gene transcripts in rat liver

CONTEXT

Spices and herbs are recognized sources of natural antioxidants that can protect from oxidative stress, thus play an important role in chemoprevention of liver diseases. Ginger is used worldwide primarily as a spicy condiment.

OBJECTIVE

This study evaluated the ability of ginger extract (GE) to ameliorate oxidative-hepatic toxicity induced by lead acetate (PbAc) in rats.

MATERIALS AND METHODS

Five groups of animals were used: group I kept as control; groups II, IV, and V received PbAc (1 ppm in drinking water daily for 6 weeks, and kept for an additional 2 weeks without PbAc exposure); group III treated orally with GE (350 mg/kg body weight, 4 d per week) for 6 weeks; group IV (protective) received GE for 2 weeks before and simultaneously with PbAc; and group V (treatment) received GE for 2 weeks after PbAc exposure.

RESULTS

GC-MS analysis of GE revealed its content of gingerol (7.09%), quercetin (3.20%), dl-limonene (0.96%), and zingiberene (0.18%). Treatment of PbAc-treated rats with GE has no effect on hepatic Pb concentrations. However, it maintained serum aspartate aminotransferase level, increased hepatic glutathione (157%), glutathione S-transferase (GST) (228%), glutathione peroxidase (GPx) (138%) and catalase (CAT) (112%) levels, and reduced hepatic malondialdehyde (80%). Co-treatment of PbAc group with GE upregulated mRNA expression of antioxidant genes: GST-α1 (1.4-fold), GPx1 (1.8-fold), and CAT (8-fold), while post-treatment with GE upregulated only mRNA expression of GPx1 (1.5-fold).

CONCLUSION

GE has an antioxidant protective efficacy against PbAc-induced hepatotoxicity, which appears more effective than its therapeutic application. However, the changes in antioxidant gene expression were not reflected at the protein level.

Hesperetin derivatives: Synthesis and anti-inflammatory activity

Sixteen novel hesperetin derivatives containing Mannich base moiety were designed and synthesized and their anti-inflammatory activities were evaluated by inhibiting tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in mouse RAW264.7 macrophages. Compounds 3a-3k showed better hydrophilic, while compounds 3l-3p with aromatic groups was hydrophobic. The anti-inflammatory activity of title compounds was correlated with logP values, among them, compounds 3c, 3e and 3i with minus logP values exhibited best anti-inflammatory activity through decreasing both IL-6 and TNF-α. Furthermore, the expression of LPS-induced notch1 and inos was reduced by compounds 3c, 3e, and 3i, and compound 3e attenuated LPS-induced inos protein levels in a dose-dependent manner.

Efficacy of doxorubicin-transferrin conjugate in apoptosis induction in human leukemia cells through reactive oxygen species generation

Background

Doxorubicin (DOX) is a small molecular cytotoxic agent that can be transferred efficiently to cancer cells by nanocarriers. This anthracycline antibiotic serves as an effective anti-neoplastic drug against both hematological and solid malignancies. Here, we set out to assess the capacity of a novel doxorubicin - transferrin conjugate (DOX-TRF) to provoke apoptosis in human normal and leukemia cells through free radicals produced via a redox cycle of doxorubicin (DOX) when released from its conjugate.

Methods

After DOX-TRF exposure, we determined the time-course of apoptotic and necrotic events, the generation of reactive oxygen species (ROS), changes in mitochondrial membrane potential, as well as alterations in cytochrome c levels and intracellular calcium concentrations in human leukemia-derived cell lines (CCRF-CEM, K562 and its doxorubicin-resistant derivative K562/DOX) and normal peripheral blood-derived mononuclear cells (PBMC).

Results

We found that DOX-TRF can induce apoptosis in all leukemia-derived cell lines tested, which was associated with morphological changes and decreases in mitochondrial membrane potential. In comparison to free DOX treated cells, we observed a time-dependency between a higher level of ROS generation and a higher drop in mitochondrial membrane potential, particularly in the doxorubicin-resistant cell line. In addition, we found that the apoptotic cell death induced by DOX-TRF was directly associated with a release of cytochrome c from the mitochondria and an increase in intracellular calcium level in all human leukemia-derived cell lines tested.

Conclusions

Our data indicate that DOX-TRF is considerably more cytotoxic to human leukemia cells than free DOX. In addition, we show that DOX-TRF can effectively produce free radicals, which are directly involved in apoptosis induction.

Evaluation of lead and essential elements in whole blood during pregnancy: a cross-sectional study

AIM

Physiological concentrations of some elements fluctuate during pregnancy due to the increased requirements of growing fetus and changes in the maternal physiology. The aim of the study is to evaluate the distribution at different stages of pregnancy in healthy Chinese women and to show the association between trace elements and gestational age-specific reference intervals.

METHODS

A cross-sectional study was performed in 1089 pregnant women and 677 nonpregnant control women. Five element concentrations, including Cu, Zn, Ca, Mg, Pb in the blood were determined by atomic absorption spectrometry. Spearman's rank correlation test was used to assess the relationship between weeks of gestation and blood element concentrations.

RESULTS

The mean levels of Cu and Mg were 23.64 ± 4.69 μmol/L and 1.36 ± 0.12 mmol/L, respectively, in the control women. While 0.68 % of all pregnant women showed Cu levels below the normal ranges, the levels of Mg were comparable in different groups. Though the overall mean blood zinc and Ca concentrations (83.84 ± 17.50 μmol/L and 1.60 ± 0.15 mmol/L, respectively) increased gradually with the progress of gestation, the Zn and Ca deficiency levels (16.6 and 3.6 %, respectively) decreased with the advance of gestation. Compared with nonpregnant group, the concentrations of Cu, Zn, Ca, Mg, Pb during the different stages of pregnancy, as a whole, were significantly different. Positive correlations were observed between weeks of gestation and blood Cu, Ca, Pb concentrations (r = 0.301, 0.221, 0.223; P < 0.05). There was a negative correlation blood Mg concentrations and weeks of gestation (r = -0.321; P < 0.05). A weak positive correlation was noted between Zn concentrations and weeks of gestation (r = 0.125; P < 0.05).

CONCLUSION

The importance of Cu and Mg deficiency and supplementation is well realized, but, Zn/Ca deficiency and Pb exposure is still exist; the overall deficiency of pregnant women was not so optimistic. During pregnancy, the established reference values will provide an important guidance for the reasonable supplementation of essential elements and surveillance of lead overexposure.

Multiple programmed cell death pathways are involved in N-methyl-N-nitrosourea-induced photoreceptor degeneration

PURPOSE

To identify programmed cell death (PCD) pathways involved in N-methyl-N-nitrosourea (MNU)-induced photoreceptor (PR) degeneration.

METHODS

Adult C57BL/6 mice received a single MNU i.p. injection (60 mg/kg bodyweight), and were observed over a period of 7 days. Degeneration was visualized by H&E overview staining and electron microscopy. PR cell death was measured by quantifying TUNEL-positive cells in the outer nuclear layer (ONL). Activity measurements of key PCD enzymes (calpain, caspases) were used to identify the involved cell death pathways. Furthermore, the expression level of C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78), key players in endoplasmic reticulum (ER) stress-induced apoptosis, was analyzed using quantitative real-time PCR.

RESULTS

A decrease in ONL thickness and the appearance of apoptotic PR nuclei could be detected beginning 3 days post-injection (PI). This was accompanied by an increase of TUNEL-positive cells. Significant upregulation of activated caspases (3, 9, 12) was found at different time periods after MNU injection. Additionally, several other players of nonconventional PCD pathways were also upregulated. Consequently, calpain activity increased in the ONL, with a maximum on day 7 PI and an upregulation of CHOP and GRP78 expression beginning on day 1 PI was found.

CONCLUSIONS

The data indicate that regular apoptosis is the major cause of MNU-induced PR cell death. However, alternative PCD pathways, including ER stress and calpain activation, are also involved. Knowledge about the mechanisms involved in this mouse model of PR degeneration could facilitate the design of putative combinatory therapeutic approaches.