Elevated level of neuroserpin is an indication for the resistance to gambogic acid-induced apoptosis and oxidative stress in triple-negative breast cancer cells

Background

The triple-negative breast cancer (TNBC) subtype, characterized by loss of HER2, estrogen, and progesterone receptors, displays aggressive phenotype and poor prognosis compared to other BC subtypes. Since the TNBC cells are devoid of receptors, endocrine therapy is an ineffective option for TNBC patients, necessitating canonical chemotherapy strategies to treat TNBC. It is crucial to use alternative and natural agents to support chemotherapy in TNBC.

Objectives

To clarify the molecular mechanism of the tumorigenic effects of gambogic acid (GA) on TNBC cells with different epithelial character since GA has a wide spectrum of anticancer activity for most cancer types.

Methods

We determined the cytotoxic dose of GA incubation of TNBC cells (MDA-MB-231 and BT-20 cells) for 24 h. We performed the MTT test and toluidine blue (TB) staining protocol for TNBC cells. We analyzed E-cadherin, N-cadherin, Bax, and neuroserpin mRNAs in both cells by qPCR. We evaluated apoptosis using DAPI staining and assessed the ROS using the 2',7'-dichlorofluorescin diacetate (DCFH-DA) method.

Results

We determined the IC50 concentrations of GA in MDA-MB-231 and BT-20 cells to be 315.8 nM and 441.8 nM, respectively. TB staining showed that BT-20 cells survive at excessive cytotoxic doses of GA, while most of the MDA-MB-231 cells were killed. Also, we found that BT-20 cells are more resistant to GA-induced apoptosis and oxidative stress than the MDA-MB-231 cells. qPCR results showed that GA upregulated neuroserpin, an oxidative stress-relieving factor in the BT-20 cells, but not in the MDA-MB-231 cells.

Conclusions

The elevated level of neuroserpin could be a predictive marker to determine the development of resistance to chemotherapeutic agents.

N-Acetyl-L-cysteine facilitates tendon repair and promotes the tenogenic differentiation of tendon stem/progenitor cells by enhancing the integrin α5/β1/PI3K/AKT signaling

BACKGROUND

Tendon injury is associated with oxidative stress, leading to reactive oxygen species (ROS) production and inflammation. N-acetyl-L-cysteine (NAC) is a potent antioxidant. However, how NAC affects the biological functions of tendon stem/progenitor cells (TSPCs) and tendon repair has not been clarified.  METHOD: The impacts of NAC on the viability, ROS production, and differentiation of TSPCs were determined with the cell counting kit-8, fluorescence staining, Western blotting, and immunofluorescence. The effect of NAC on gene transcription in TSPCs was analyzed by transcriptomes and bioinformatics and validated by Western blotting. The potential therapeutic effect of NAC on tendon repair was tested in a rat model of Achilles tendon injury.

RESULTS

Compared with the untreated control, treatment with 500 µM NAC greatly promoted the proliferation of TSPCs and significantly mitigated hydrogen peroxide-induced ROS production and cytotoxicity in vitro. NAC treatment significantly increased the relative protein expression of collagen type 1 alpha 1 (COL1A1), tenascin C (TNC), scleraxis (SCX), and tenomodulin (TNMD) in TPSCs. Bioinformatics analyses revealed that NAC modulated transcriptomes, particularly in the integrin-related phosphoinositide 3-kinase (PI3K)/AKT signaling, and Western blotting revealed that NAC enhanced integrin α5β1 expression and PI3K/AKT activation in TSPCs. Finally, NAC treatment mitigated the tendon injury, but enhanced the protein expression of SCX, TNC, TNMD, and COLIA1 in the injured tissue regions of the rats.

CONCLUSION

NAC treatment promoted the survival and differentiation of TSPCs to facilitate tendon repair after tendon injury in rats. Thus, NAC may be valuable for the treatment of tendon injury.

Plasma thiol/disulphide homeostasis changes in patients with relapsing-remitting multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a neuroinflammatory disease and inflammation and oxidative stress play important roles in its pathology. Thiol/disulphide homeostasis (TDH) is a special oxidative stress biomarker that has been found to be affected in several disorders including MS. There is no study demonstrating the effects of attack status of the relapsing-remitting multiple sclerosis (RRMS) patients on TDH levels. Our aim was to determine TDH levels in three different periods of RRMS patients and healthy individuals.

METHODS

The study was carried out in 29 patients with RRMS without a prior attack in the last twelve months (MS Control), 21 RRMS patients having a clinical acute attack within the last week (MS relapse), 12 of 21 MS relapse patients one month after the onset of attack and following 1000 mg methylprednisolone for 7 days (MS Remission) and 30 age- and sex-matched healthy individuals. TDH status was determined using an automated spectrophotometric analysis method. TDH levels in all patient groups and control subjects were compared with each other.

RESULTS

The lowest native thiol, total thiol levels and native thiol/total thiol ratio were found in the MS relapse patients in comparison to the MS control, MS remission groups and healthy controls. In contrast, disulphide levels, disulphide/native thiol and disulphide/total thiol ratios were highest in the MS relapse group compared to the other patient groups and healthy subjects.

CONCLUSION

Our findings indicate that increased oxidative stress in RRMS patients is reflected with decreased native and total thiol and increased disulphide levels. Since the formation of disulphide bonds is reversible, the progression of RRMS involving abnormal TDH may be controlled, converting disulphides to thiols. So, we suggest determining the dynamic TDH status as a novel and special biomarker in the diagnosis and prognosis of the RRMS patients.

A new combination strategy to enhance apoptosis in cancer cells by using nanoparticles as biocompatible drug delivery carriers

Some experimental and clinical studies have been conducted for the usage of chemotherapeutic drugs encapsulated into nanoparticles (NPs). However, no study has been conducted so far on the co-encapsulation of doxorubicin (Dox) and epoxomicin (Epo) into NPs as biocompatible drug delivery carriers. Therefore, we investigated if co-encapsulation of doxorubicin (Dox) and/or epoxomicin (Epo) into NPs enhance their anticancer efficiency and prevent drug resistance and toxicity to normal cells. We synthesized Dox and/or Epo loaded poly (lactic-co-glycolic acid) (PLGA) NPs using a multiple emulsion solvent evaporation technique and characterized them in terms of their particle size and stability, surface, molecular, thermal, encapsulation efficiency and in vitro release properties. We studied the effects of drug encapsulated NPs on cellular accumulation, intracellular drug levels, oxidative stress status, cellular viability, drug resistance, 20S proteasome activity, cytosolic Nuclear Factor Kappa B (NF-κB-p65), and apoptosis in breast cancer and normal cells. Our results proved that the nanoparticles we synthesized were thermally stable possessing higher encapsulation efficiency and particle stability. Thermal, morphological and molecular analyses demonstrated the presence of Dox and/or Epo within NPs, indicating that they were successfully loaded. Cell line assays proved that Dox and Epo loaded NPs were less cytotoxic to single-layer normal HUVECs than free Dox and Epo, suggesting that the NPs would be biocompatible drug delivery carriers. The apoptotic index of free Dox and Epo increased 50% through their encapsulation into NPs, proving combination strategy to enhance apoptosis in breast cancer cells. Our results demonstrated that the co-encapsulation of Dox and Epo within NPs would be a promising treatment strategy to overcome multidrug resistance and toxicity to normal tissues that can be studied in further in vivo and clinical studies in breast cancer.

Plasma thiol/disulphide homeostasis changes in patients with restless legs syndrome

OBJECTIVES

Restless legs syndrome (RLS) is a common neurological condition. Oxidative stress plays an important role in its pathogenesis. Thiol-disulphide homeostasis (TDH) is a new biomarker of oxidative stress. We studied plasma TDH to determine whether TDH could be used as a new biomarker for RLS and evaluated correlations between TDH and various disease severity rating scales.

METHODS

A total of 25 RLS patients and 25 healthy controls were included into the study. TDH status was determined using an automated spectrophotometric analysis method and correlations were analyzed between the TDH status and various disease rating scales in the RLS patients.

RESULTS

Plasma total (401±27 μmol/L) and native thiol (354±30 μmol/L) levels were significantly lower, but disulphide level (24±6 μmol/L) was significantly (<0.0001) higher in the RLS patients compared to the controls (455±36, 424±37, 15±5 μmol/L, respectively). The disulphide/native thiol and disulphide/total thiol ratios increased, in contrast, native thiol/total thiol ratio decreased significantly in the RLS patients compared to the healthy controls (<0.0001). The disulphide levels correlated positively with age and various rating scores of the RLS patients. International Restless Legs Syndrome Study Group (IRLSSG) rating score and age correlated negatively with the total and native thiol levels.

CONCLUSIONS

Our findings indicate increased oxidative stress in the RLS patients reflected by decreased native and total thiol, and increased disulphide levels and positive correlations between the disulphide levels and various rating scores. We suggest dynamic TDH status to be used as a novel biomarker for the diagnosis and follow-up of the RLS patients.

Mancozeb induces testicular dysfunction through oxidative stress and apoptosis: Protective role of N-acetylcysteine antioxidant

Mancozeb (MZB) is one of the fungicides used in pest control programs that might affect human health including reproductive system. The aim of this study was to demonstrate the mechanisms through which MZB induces testicular tissue damage and the probable protective effect of N-acetylcysteine (NAC), a modified amino acid, with antioxidant property, against MZB toxicity in an animal model. Male albino mice ( n = 8) were exposed to different doses of MZB (250 and 500 mg/kg/day) by oral gavage without or with NAC (200 mg/kg, twice/week) for 40 days. Sub-chronic MZB dose-dependently decreased sperm motility and count. Exposure to MZB increased lipid peroxidation and protein carbonyl, while it reduced antioxidant enzymes activities, total antioxidant capacity, and glutathione content. The histopathological examination clearly showed deleterious changes in the testicular structure. At the molecular levels, the results of quantitative real time-poly chain reaction (qRT-PCR) showed that MZB upregulated oxidative stress markers inducible nitric oxide synthase (iNOS) and NADPH oxidase 4 (NOX4) and downregulated expression of the glutathione peroxidase 1 (Gpx1) gene as one of the most important antioxidant enzymes. MZB also induced apoptosis dose-dependently in the testes as determined by the terminal dUTP nick-end labeling assay and immunoblotting. NAC administration decreased the mRNA levels of both iNOS and NOX4 with a concomitant increase in Gpx1 expression. It also significantly decreased MZB-induced oxidative stress and apoptosis. Collectively, the present study showed MZB-induced oxidative damage in testes leading to apoptosis. It revealed that antioxidants such as NAC can mitigate oxidant injury induced by the dithiocarbamate pesticides in the reproductive system.

Curcumin down-regulates IL-17A mediated p53-fibrinolytic system in bleomycin induced acute lung injury in vivo

Bleomycin (BLM) induced cellular damage causes inflammation in the alveolar compartment and impairment of fibrinolytic system leads to alveolar epithelial cell apoptosis. Here, we describe novel inflammatory pathway associated with p53-fibrinolytic system and apoptosis of alveolar epithelial cells and pharmacological efficiency of curcumin against this action. In the present study we used C57BL/6 mice. The specific dose and time interval of curcumin were analyzed to assess the intervention. Experiments were designed to investigate the IL-17A mediated modulation in the alveolar epithelial cell apoptosis and injury. Various techniques such as Western blot, RT-PCR, Immunohistochemistry were used for this study. We observed that the BLM-induced lung injury and its progression were successfully regulated by the effective dose and time intervention of curcumin. There was also decreased expression of chemokines, p53, and fibrinolytic components such as PAI-1 and increased uPA, uPAR expression, and decreased alveolar epithelial cell apoptosis, which indicates the IL-17A mediated novel inflammatory pathway. It is confirmed that the IL-17A involved in the modulation of p53-fibrinolytic system and epithelial cell apoptosis in BLM induced mice. The cross-talk between the inflammatory, fibrinolytic, and apoptotic pathways were resolved by curcumin intervention. This pathway and intervention could serve as a modern therapy to resolve the complications to cure the lung injury and its progression.

Effects of bleomycin and antioxidants on the fatty acid profile of testicular cancer cell membranes

Bleomycin is used in chemotherapy regimens for the treatment of patients having testicular germ-cell tumor (TGCT). There is no study in the literature investigating the effects of bleomycin on membrane lipid profile in testicular cancer cells. We investigated membrane fatty acid (FA) profiles isolated, derivatized and analyzed by gas chromatography of NTera-2 testicular cancer cells incubated with bleomycin (Bleo) for 24 h in the absence and presence of N-Acetyl-L-Cysteine (NAC) and curcumin (Cur) as commonly used antioxidant adjuvants. At the same time the MAPK pathway and EGFR levels were followed up. Bleomycin treatment increased significantly saturated fatty acids (SFA) of phospholipids at the expense of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Bleomycin also led to a significant increase in the trans lipid isomers of oleic and arachidonic acids due to its free radical producing effect. Incubation with bleomycin increased the p38 MAPK and JNK levels and downregulated EGFR pathway. Coincubation of bleomycin with NAC reversed effects caused by bleomycin. Our results highlight the important role of membrane fatty acid remodeling occurring during the use of bleomycin and its concurrent use with antioxidants which can adjuvate the cytotoxic effects of the chemotherapeutic agents.