EGFR overexpression increases radiotherapy response in HPV-positive head and neck cancer through inhibition of DNA damage repair and HPV E6 downregulation.

High-risk Human Papillomavirus (HPV) infections have recently emerged as an independent risk factor in head and neck squamous cell carcinoma (HNSCC). There has been a marked increase in the incidence of HPV-induced HNSCC subtype, which demonstrates different genetics with better treatment outcome. Despite the favourable prognosis of HPV-HNSCC, the treatment modality, consisting of high dose radiotherapy (RT) in combination with chemotherapy (CT), remains similar to HPV-negative tumours, associated with toxic side effects. Epidermal growth factor receptor (EGFR) is overexpressed in over 80% of HNSCC and correlates with RT resistance. EGFR inhibitor Cetuximab is the only FDA approved targeted therapy for both HNSCC subtypes, however the response varies between HNSCC subtypes. In HPV-negative HNSCC, Cetuximab sensitises HNSCC to RT improving survival rates. To reduce adverse cytotoxicity of CT, Cetuximab has been approved for treatment de-escalation of HPV-positive HNSCC. The results of several recent clinical trials have concluded differing outcome to HPV-negative HNSCC. Here we investigated the role of EGFR in HPV-positive HNSCC response to RT. Remarkably, in HPV-positive HNSCC cell lines and in vivo tumour models, EGFR activation was strongly indicative of increased RT response. In response to RT, EGFR activation induced impairment of DNA damage repair and increased RT response. Furthermore, EGFR was found to downregulate HPV oncoproteinE6 expression and induced p53 activity in response to RT. Collectively, our data uncovers a novel role for EGFR in virally induced HNSCC and highlights the importance of using EGFR-targeted therapies in the context of the genetic makeup of cancer.

Terpenoids and phenolics of Micromeria persica.

Phytochemical investigation of the aerial parts of Micromeria persica led to the isolation of a new oleane type triterpenoid ester (1), together with six known compounds 2-7), comprising one phenyl ethanoid ester, one glycosylated flavonoid, two triterpenoids, and two steroids. Their structures were elucidated by interpretation of their one-dimensional and two-dimensional NMR spectra and completed by the analysis of the HRESIMS data. Compounds 1 and 3 were evaluated for their cytotoxic feature against human breast adenocarcinoma cell line (MDA-MB231) and human prostate cancer cell line (DU145). However, they did not show positive effect (IC50 > 75µM).[Figure: see text].

Cerium and Yttrium Oxide Nanoparticles and Nano-selenium Produce Protective Effects Against H2O2-induced Oxidative Stress in Pancreatic Beta Cells by Modulating Mitochondrial Dysfunction.

BACKGROUND: Type 1 diabetes mellitus is characterized by the destruction of insulin- producing Beta cells in the pancreas. Researchers hope that islet transplantation will help to patients with insulin-dependent diabetes mellitus (IDDM). Oxidative stress is the most important challenge that beta cells face to it after isolation, and mitochondrial dysfunction is a crucial mediator in beta cells death. Hence, therapeutic approaches can shift to antioxidants through the application of nanoparticles such as cerium and yttrium oxide nanoparticles (Cer and Ytt Ox NPs) and nano-selenium (Nan Se). OBJECTIVE: This study evaluates the effects of Cer and Ytt Ox NPs and Nan Se on H2O2- induced oxidative stress in pancreatic beta cells with focus on mitochondrial dysfunction pathway. METHODS: CRI-D2 beta-cell line were pretreated with Cer Ox NPs (200 µM) + Ytt Ox NPs (0.5 µg/mL) for 3 days and/or Nan Se (0.01 µM) for 1 day. Then markers of oxidative stress, mitochondrial dysfunction, insulin and glucagon secretion were measured. RESULTS: We reported a decrease in H2O2-induced reactive oxygen species (ROS) level and glucagon secretion, and an increase in H2O2-reduced ATP/ADP ratio, MMP, as well as UCP2 protein expression, and insulin secretion by pretreatment of CRI-D2 cells with Cer and Ytt Ox NPs and/or Nan Se. CONCLUSION: We found maximum protective effect with Cer and Ytt Ox NPs on CRI-D2 beta-cell line exposed by H2O2 for keeping beta cells alive until transplant whereas combination of Cer and Ytt Ox NPs and Nan Se had very little protective effect in this condition.

An Adaptive Robust Control Strategy in a Cancer Tumor-Immune System under Uncertainties.

We propose an adaptive robust control for a second order nonlinear model of the interaction between cancer and immune cells of the body to control the growth of cancer and maintain the number of immune cells in an appropriate level. Most of the control approaches are based on minimizing the drug dosage based on an optimal control structure. However, in many cases, measuring the exact quantity of the model parameters is not possible. This is due to limitation in measuring devices, variational and undetermined characteristics of micro-environmental factors. It is of great importance to present a control strategy that can deal with these unknown factors in a nonlinear model.

Phosphodiesterase 4 and 7 inhibitors produce protective effects against high glucose-induced neurotoxicity in PC12 cells via modulation of the oxidative stress, apoptosis and inflammation pathways.

Diabetic neuropathy (DN) is the most common diabetic complication. It is estimated diabetic population will increase to 592 million by the year 2035. This is while at least 50-60% of all diabetic patients will suffer from neuropathy in their lifetime. Oxidative stress, mitochondrial dysfunction, apoptosis, and inflammation are crucial pathways in development and progression of DN. Since there is also no selective and effective therapeutic agent to prevent or treat high glucose (HG)-induced neuronal cell injury, it is crucial to explore tools by which one can reduce factors related to these pathways. Phosphodiesterase 4 and 7 (PDE 4 and 7) regulate oxidative damage, neurodegenaration, and inflammatory responses through modulation of cyclic adenosine monophosphate (cAMP) level, and thus can be as important drug targets for regulating DN. The aim of this study was to evaluate the protective effects of inhibitors of PDE 4 and 7, named rolipram and BRL5048, on HG-induced neurotoxicity in PC12 cells as an in vitro cellular model for DN and determine the possible mechanisms for theirs effects. We report that the PC12 cells pre-treatment with rolipram (2 µM) and/or BRL5048 (0.2 µM) for 60 min and then exposing the cells to HG (4.5 g/L for 72 h) or normal glucose (NG) (1 g/L for 72 h) condition show: (1) significant attenuation in ROS, MDA and TNF-a levels, Bax/Bcl-2 ratio, expression of caspase 3 and UCP2 proteins; (2) significant increase in viability, GSH/GSSG ratio, MMP and ATP levels. All these data together led us to propose PDE 4 and 7 inhibitors, and specifically, rolipram and BRL5048, as potential drugs candidate to be further studied for the prevention and treatment of DN.

Sildenafil protective effects on high glucose-induced neurotoxicity in PC12 cells: the role of oxidative stress, apoptosis, and inflammation pathways in an in vitro cellular model for diabetic neuropathy.

Objectives Diabetic neuropathy (DN) induces lifetime disability and there is currently no effective therapy to treat or to minimize patients suffering, so it is thereby imperative to develop therapeutic strategies for this disease. Since oxidative stress, mitochondrial dysfunction, apoptosis, and inflammation are crucial mechanisms in development and progression of DN, it is important to explore tools by which one can reduce factors related to these pathways. Herein, the understandings of the sildenafil neuroprotective effect through increase of cGMP level and the mediation of oxidative stress, apoptosis, and inflammation pathways on neurotoxicity induced by high glucose (HG) in PC12 cells as an in vitro cellular model for DN were investigated. Methods We reported that the PC12 cells pre-treatment with sildenafil (0.008 µM) for 60 min and then exposing the cells to HG (25 mM for 72 h) or normal glucose (NG) (5 mM for 72 h) condition, show: Results (1) significant attenuation in reactive oxygen species, MDA and TNF-a levels, Bax/Bcl-2 ratio, expression of caspase 3 and UCP2 proteins; (2) significant increase in viability, GSH/GSSG ratio, mitochondrial membrane potential, and ATP levels. Conclusion All these data together led us to propose neuroprotective effect of sildenafil is probably through its antioxidant, antiapoptotic, and anti-inflammatory activities. Of course, further studies are required to explain the underlying mechanism of the sildenafil effects.

Eupatorin and Salvigenin Potentiate Doxorubicin-Induced Apoptosis and Cell Cycle Arrest in HT-29 and SW948 Human Colon Cancer Cells

Background: Cancer persists as one of the world's most pressing maladies. Notable points about chemotherapy are drug side effects which are almost universally encountered. Emerging knowledge focusing on mechanisms of toxicity due to chemotherapy has led to characterization of novel methods, including the exploitation of natural compounds, in combination therapies. Flavonoids are natural polyphenolic compounds that play protective roles against tumor cell development. The focus of this study was apoptotic effects of two flavonoids, eupatorin and salvigenin, in combination with doxorubicin on a cellular model of colon cancer. Method: Upon establishing a non-effective dose of doxorubicin, and effective doses of eupatorin (100µM) and salvigenin (150µM) via MTT, morphological features of apoptosis were distinguished using DAPI staining and cell cycle blockage in the sub-G1 phase. Apoptosis was determined by annexin/ PI and western blotting. ROS levels and MMP were measured to show any role of mitochondria in apoptosis. Results: Co-administration of flavonoids with doxorubicin induced apoptosis via the mitochondrial pathway as mitochondrial membrane potential and ROS production were changed. Annexin/PI analysis demonstrated that apoptosis frequency was increased with the combination treatments in colon cancer cells. Finally, the combination of these flavonoids with doxorubicin increased the Bax/Bcl-2 ratio, caspase-3 expression and PARP cleavage. Conclusion: Combination of flavonoids with doxorubicin induces apoptosis and enhances effect on cancer cells which might allow amelioration of side effects by dose lowering.

Antioxidant and Anticancer Activities of Walnut (Juglans regia L.) Protein Hydrolysates Using Different Proteases.

Walnut (Juglans regia L.) contains approximately 20-25 % protein with abundant essential amino acids. The enzymatic hydrolysate of Persian walnut (Chandler) seed proteins was prepared by incubation with three different proteases, including pancreatic chymotrypsin and trypsin, and a microbial enzyme proteinase K. The hydrolysates were found to possess excellent antioxidant capacities. The peptide fractions scavenged the 2, 2'-anizo-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) free radicals and inhibited the activity of reactive oxygen species. Walnut protein hydrolysates were also tested, for the first time, against the viability of human breast (MDA-MB231) and colon (HT-29) cancer cell lines. MTT, [3-(4, 5dimethylthiazolyl)-2,5-diphenyl-tetrazolium bromide], assay was used to assess in vitro cancer cell viability upon treatment with the peptide fractions. The peptide fractions showed cell growth inhibition of 63 ± 1.73 % for breast cancer and 51 ± 1.45 % for colon cancer cells. Thus, a direct correlation between antioxidant and anticancer activities of walnut peptide fractions exists and supports their potential therapeutic benefit.

Labdane Diterpenoids from Salvia leriifolia: Absolute Configuration, Antimicrobial and Cytotoxic Activities.

Fractionation of an n-hexane extract of the aerial parts of Salvia leriifolia led to the isolation of two new (1, 2) and two known (3, 4) labdane diterpenoids, together with three other known compounds. The structures were established by a combination of 1D and 2D NMR, and HRESIMS. The structures of 1 and 3 were confirmed by single-crystal X-ray analysis. The absolute configuration of 1-4 was established by electronic circular dichroism spectroscopy. Compounds 1-4 were evaluated for their cytotoxic activities against MCF-7 human breast cancer cells. Labdanes 3 and 4 were additionally tested against MDA-MB231 human breast cancer and DU-145 human prostate cancer cell lines. Compound 4 showed IC50 values of 25, 50, and 50 µM against MCF-7, MDA-MB231, and DU-145 cells, respectively. Compounds 1-4 were tested for activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. Compound 3 showed an MIC of 213 µM against methicillin-resistant S. aureus.

Involvement of p-CREB and phase II detoxifying enzyme system in neuroprotection mediated by the flavonoid calycopterin isolated from Dracocephalum kotschyi.

PURPOSE: There is an increasing amount of experimental evidence that oxidative stress has a central role in the neuropathology of neurodegenerative diseases. It has been suggested that the loss of cell function results from the increased oxidative damage to proteins and DNA. Herein, we investigated the effect of a natural neuroprotective flavonoid, calycopterin, on H2O2-induced disruption of phase II detoxifying enzyme system and cAMP response element binding protein (CREB) phosphorylation. METHODS: PC12 cells were treated with 25, 50 and 100 µM of calycopterin for 3h, followed by adding H2O2 (150 µM) for 24 h. The extent of apoptosis was assessed by comet assay. The level of phosphorylated CREB, nuclear factor erythroid 2-related factor 2 (Nrf2), glutamylcysteine synthetase (γ-GCS) and heme oxygenase 1 (HO-1) were measured by western blot method. The concentration of glutathione (GSH) was determined in whole cell lysate using dithionitrobenzoic acid method. Superoxide dismutase (SOD) activity was measured by colorimetric assay. RESULT: Morphological analysis of protection induced by calycopterin, determined by comet assay, showed that calycopterin reduced DNA in tail. We found that H2O2 decreased mitochondrial membrane potential (MMP), while, calycopterin prevented this decrease in MMP in presence of H2O2. In H2O2-treated cells, calycopterin also suppressed cytochrome C release to cytosol that is necessary for maintaining mitochondrial homeostasis in survived cells. Moreover, calycopterin, in presence of H2O2 inhibited the decrease caused by oxidative stress in stress-sensing transcription factors, CREB and Nrf2, which play an important role in antioxidant capacity of the cell. There was also an increase in γ-GCS and HO-1 levels in calycopterin pretreated cells. In the presence of H2O2, calycopterin inhibited decrease in GSH level and SOD activity. CONCLUSION: We provided documentation of neuroprotective effect of a natural flavone, calycopterin, against H2O2-induced oxidative stress in differentiated PC12 cells by modulating the level of CREB phosphorylation and Nrf2 pathway.

Calycopterin promotes survival and outgrowth of neuron-like PC12 cells by attenuation of oxidative- and ER-stress-induced apoptosis along with inflammatory response.

There is mounting evidence implicating the role of oxidative stress induced by reactive oxygen species (ROS) in neurodegenerative disease, including Alzheimer's disease. Herein we investigated the neuroprotective potential of a natural flavonoid, calycopterin, against H(2)O(2)-induced cell death in differentiated PC12 cells. We pretreated PC12 cells with 25, 50, and 100 µM calycopterin followed by the addition of H(2)O(2) as an oxidative stress agent. We measured cell viability by the MTT test and found that 50 µM is the best protective concentration of calycopterin. Moreover, we measured six different parameters of neurite outgrowth. Interestingly, we found that calycopterin not only protects PC12 cells against H(2)O(2)-induced apoptosis but also defends against the destructive effect of oxidative stress on the criteria of neural differentiation. Calycopterin decreased ER stress-associated proteins including calpain and caspase-12, and suppressed ERK, JNK, and p38 MAPK phosphorylation. Moreover, calycopterin inhibited H(2)O(2)-induced nuclear translocation of nuclear factor-κB, a known regulator of a host of genes involved in specific stress and inflammatory responses. This observation was perfectly in agreement with the decrease of COX-2 and TNF-α levels. Calycopterin reduced intracellular ROS levels and increased catalase activity. The protective effect of this compound could represent a promising approach for the treatment of neurodegenerative diseases.

Neuroprotective effect of Salvia sahendica is mediated by restoration of mitochondrial function and inhibition of endoplasmic reticulum stress.

Herein, we investigated the protective effect of Salvia sahendica against H(2)O(2)-induced cell death in rat pheochromocytoma (PC12) cells. Our data show that S. sahendica blocks apoptosis pathway by inhibition of cytochrome c release from mitochondria and leakage of calcium from endoplasmic reticulum. It also activates/inactivates two members of Bcl-2 family, Bax and Bcl-2. Bax inhibition and Bcl-2 activation suppress release of cytochrome c from mitochondria that prevents cleavage of caspase-3. Besides S. sahendica suppresses ER stress via attenuation of intracellular levels of calcium. Suppression of ER stress decreased calpain activation and subsequently cleavage of caspase-12. Altogether, these results indicate that S. sahendica protects PC12 cells treated with H(2)O(2) via suppression of upstream factors of apoptosis pathway. While oxidative stress is an early event in Alzheimer disease, it seems that S. sahendica prevents deleterious effects of reactive oxygen species by stabilizing mitochondrial membranes and inhibiting ER stress.