The role of flavonoids in the regulation of epithelial-mesenchymal transition in cancer: A review on targeting signaling pathways and metastasis

One of the hallmarks of cancer is metastasis, a process that entails the spread of cancer cells to distant regions in the body, culminating in tumor formation in secondary organs. Importantly, the proinflammatory environment surrounding cancer cells further contributes to cancer cell transformation and extracellular matrix destruction. During metastasis, front-rear polarity and emergence of migratory and invasive features are manifestations of epithelial-mesenchymal transition (EMT). A variety of transcription factors (TFs) are implicated in the execution of EMT, the most prominent belonging to the Snail Family Transcriptional Repressor (SNAI) and Zinc Finger E-Box Binding Homeobox (ZEB) families of TFs. These TFs are regulated by interaction with specific microRNAs (miRNAs), as miR34 and miR200. Among the several secondary metabolites produced in plants, flavonoids constitute a major group of bioactive molecules, with several described effects including antioxidant, antiinflammatory, antidiabetic, antiobesogenic, and anticancer effects. This review scrutinizes the modulatory role of flavonoids on the activity of SNAI/ZEB TFs and on their regulatory miRNAs, miR-34, and miR-200. The modulatory role of flavonoids can attenuate mesenchymal features and stimulate epithelial features, thereby inhibiting and reversing EMT. Moreover, this modulation is concomitant with the attenuation of signaling pathways involved in diverse processes as cell proliferation, cell growth, cell cycle progression, apoptosis inhibition, morphogenesis, cell fate, cell migration, cell polarity, and wound healing. The antimetastatic potential of these versatile compounds is emerging and represents an opportunity for the synthesis of more specific and potent agents.

Gossypetin Is a Novel Modulator of Inflammatory Cytokine Production and a Suppressor of Osteosarcoma Cell Growth

Osteosarcoma (OS) is a common childhood sarcoma, and its treatment is hindered by adverse effects, chemoresistance, and recurrence. Interleukin (IL)-6 production by tumors plays a significant role in inflammation, carcinogenesis, and metastasis. This study aimed to investigate the antiproliferative potential of luteolin derivatives in OS and to evaluate interleukin production. MG-63, Saos-2, HOS, and 143B human OS cell lines were incubated with luteolin and eight derivatives containing hydroxy, chlorine, or alkyl substitutions. The cell viability and growth were evaluated in the presence of these compounds. Apoptosis was also examined through the analysis of the Bax expression and caspase-3 activity. Finally, the gossypetin effects were measured regarding the production of proinflammatory cytokines interleukin (IL)-6, IL-1β, and IL-12p70. Our findings show that gossypetin was the most potent compound, with proliferation-suppressing activities that induced a series of critical events, including the inhibition of the cell viability and growth. Apoptosis was associated with enhanced caspase-3 activity and increased Bax expression, indicating the involvement of the intrinsic pathway of apoptosis. Moreover, pre-/co-treatment with gossypetin significantly reduced the autocrine production of proinflammatory cytokines. Further investigation is required; nevertheless, considering the link between inflammation, carcinogenesis, and metastasis in OS, our findings suggest that gossypetin exhibits anti-proliferative and anti-inflammatory properties that are potentially relevant in the clinical context.

Burden of non-communicable diseases among adolescents aged 10-24 years in the EU, 1990-2019: a systematic analysis of the Global Burden of Diseases Study 2019

BACKGROUND

Disability and mortality burden of non-communicable diseases (NCDs) have risen worldwide; however, the NCD burden among adolescents remains poorly described in the EU.

METHODS

Estimates were retrieved from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. Causes of NCDs were analysed at three different levels of the GBD 2019 hierarchy, for which mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) were extracted. Estimates, with the 95% uncertainty intervals (UI), were retrieved for EU Member States from 1990 to 2019, three age subgroups (10-14 years, 15-19 years, and 20-24 years), and by sex. Spearman's correlation was conducted between DALY rates for NCDs and the Socio-demographic Index (SDI) of each EU Member State.

FINDINGS

In 2019, NCDs accounted for 86·4% (95% uncertainty interval 83·5-88·8) of all YLDs and 38·8% (37·4-39·8) of total deaths in adolescents aged 10-24 years. For NCDs in this age group, neoplasms were the leading causes of both mortality (4·01 [95% uncertainty interval 3·62-4·25] per 100 000 population) and YLLs (281·78 [254·25-298·92] per 100 000 population), whereas mental disorders were the leading cause for YLDs (2039·36 [1432·56-2773·47] per 100 000 population) and DALYs (2040·59 [1433·96-2774·62] per 100 000 population) in all EU Member States, and in all studied age groups. In 2019, among adolescents aged 10-24 years, males had a higher mortality rate per 100 000 population due to NCDs than females (11·66 [11·04-12·28] vs 7·89 [7·53-8·23]), whereas females presented a higher DALY rate per 100 000 population due to NCDs (8003·25 [5812·78-10 701·59] vs 6083·91 [4576·63-7857·92]). From 1990 to 2019, mortality rate due to NCDs in adolescents aged 10-24 years substantially decreased (-40·41% [-43·00 to -37·61), and also the YLL rate considerably decreased (-40·56% [-43·16 to -37·74]), except for mental disorders (which increased by 32·18% [1·67 to 66·49]), whereas the YLD rate increased slightly (1·44% [0·09 to 2·79]). Positive correlations were observed between DALY rates and SDIs for substance use disorders (r_s=0·58, p=0·0012) and skin and subcutaneous diseases (r_s=0·45, p=0·017), whereas negative correlations were found between DALY rates and SDIs for cardiovascular diseases (r_s=-0·46, p=0·015), neoplasms (r_s=-0·57, p=0·0015), and sense organ diseases (r_s=-0·61, p=0·0005).

INTERPRETATION

NCD-related mortality has substantially declined among adolescents in the EU between 1990 and 2019, but the rising trend of YLL attributed to mental disorders and their YLD burden are concerning. Differences by sex, age group, and across EU Member States highlight the importance of preventive interventions and scaling up adolescent-responsive health-care systems, which should prioritise specific needs by sex, age, and location.

FUNDING

Bill & Melinda Gates Foundation.

Sustainable Valorization of Tomato By-Products to Obtain Bioac-Tive Compounds: Their Potential in Inflammation and Cancer Management

Tomato producing and processing industries present undoubted potential for industrial discarded products valorization whether due to the overproduction of fresh tomatoes or to the loss during processing. Although tomato by-products are not yet considered a raw material, several studies have suggested innovative and profitable applications. It is often referred to as “tomato pomace” and is quite rich in a variety of bioactive compounds. Lycopene, vitamin C, β-carotene, phenolic compounds, and tocopherol are some of the bioactives herein discussed. Tomato by-products are also rich in minerals. Many of these compounds are powerful antioxidants with anti-inflammatory properties besides modulating the immune system. Several researchers have focused on the possible application of natural ingredients, especially those extracted from foods, and their physiological and pharmacological effects. Herein, the effects of processing and further applications of the bioactive compounds present in tomato by-products were carefully reviewed, especially regarding the anti-inflammatory and anti-cancer effects. The aim of this review was thus to highlight the existing opportunities to create profitable and innovative applications for tomato by-products in health context.

Quercus suber Roots Activate Antioxidant and Membrane Protective Processes in Response to High Salinity

Cork oak (Quercus suber) is a species native to Mediterranean areas and its adaptation to the increasingly prevalent abiotic stresses, such as soil salinization, remain unknown. In sequence with recent studies on salt stress response in the leaf, it is fundamental to uncover the plasticity of roots directly exposed to high salinity to better understand how Q. suber copes with salt stress. In the present study we aimed to unveil the antioxidants and key-genes involved in the stress-responses (early vs. later responses) of Q. suber roots exposed to high salinity. Two-month-old Q. suber plants were watered with 300 mM NaCl solution and enzymatic and non-enzymatic antioxidants, lipid peroxidation and the relative expression of genes related to stress response were analysed 8 h and 6 days after salt treatment. After an 8 h of exposure, roots activated the expression of QsLTI30 and QsFAD7 genes involved in stress membrane protection, and QsRAV1 and QsCZF1 genes involved in tolerance and adaptation. As a result of the continued salinity stress (6 days), lipid peroxidation increased, which was associated with an upregulation of QsLTI30 gene. Moreover, other protective mechanisms were activated, such as the upregulation of genes related to antioxidant status, QsCSD1 and QsAPX2, and the increase of the antioxidant enzyme activities of superoxide dismutase, catalase, and ascorbate peroxidase, concomitantly with total antioxidant activity and phenols. These data suggest a response dependent on the time of salinity exposure, leading Q. suber roots to adopt protective complementary strategies to deal with salt stress.

Inhibitory activity of flavonoids against human sucrase-isomaltase (α-glucosidase) activity in a Caco-2/TC7 cellular model

Type 2 diabetes (T2D) is the most common form of diabetes, and the number of people with this metabolic disease is steadily increasing worldwide. Among the available antidiabetic agents, α-glucosidase inhibitors are the most effective at reducing postprandial hyperglycaemia (PPHG), one of the main characteristics of T2D. However, most of the studies that have been performed have used the more readily available rat intestinal preparations or yeast α-glucosidase as the enzyme source, which despite being useful and cost effective, have a questionable physiological value. The present study evaluates the inhibitory activity of a selected group of flavonoids against human sucrase-isomaltase (SI), the α-glucosidase found in Caco-2/TC7 cells. A microassay using the physiological substrates sucrose and maltose, and a synthetic substrate, p-nitrophenyl-α-D-glucopyranoside (pNPG) was performed. The most active flavonoid was compound 4 (melanoxetin), presenting an IC₅₀ value similar using the two natural substrates. In contrast, the tested flavonoids were not effective at inhibiting SI, when pNPG was used as a substrate. Hydroxylation of flavonoids at C-3 of the C ring, at C-3' and C-4' of the B ring, and at C-7 and C-8 of the A ring were the features that improved the inhibitory activity of flavonoids against human SI. These phenolic compounds deserve further exploration as alternatives to the currently available α-glucosidase inhibitors. The present study also demonstrates that the non-clinical in vitro studies conducted for the evaluation of α-glucosidase activity should use the human source rather than surrogate sources of α-glucosidase.

The global burden of adolescent and young adult cancer in 2019: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND

In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults.

METHODS

Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults.

FINDINGS

There were 1·19 million (95% UI 1·11-1·28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59·6 [54·5-65·7] per 100 000 person-years) and high-middle SDI countries (53·2 [48·8-57·9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14·2 [12·9-15·6] per 100 000 person-years) and middle SDI (13·6 [12·6-14·8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23·5 million (21·9-25·2) DALYs to the global burden of disease, of which 2·7% (1·9-3·6) came from YLDs and 97·3% (96·4-98·1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally.

INTERPRETATION

Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts.

FUNDING

Bill & Melinda Gates Foundation, American Lebanese Syrian Associated Charities, St Baldrick's Foundation, and the National Cancer Institute.

Therapeutic potential of hesperidin and its aglycone hesperetin: Cell cycle regulation and apoptosis induction in cancer models

BACKGROUND

The ability of cancer cells to divide without restriction and to escape programmed cell death is a feature of the proliferative state. Citrus flavanones are flavonoids with potential multiple anticancer actions, from antioxidant and chemopreventive, to anti-inflammatory, anti-angiogenic, cytostatic and cytotoxic in different cancer models.

PURPOSE

This review aims to summarize the current knowledge on the antiproliferative actions of the citrus flavanones hesperidin (HSD) and hesperetin (HST), with emphasis on cell cycle arrest and apoptosis.

METHODS

Cochrane Library, Scopus, Pubmed and Web of Science collection databases were queried for publications reporting antiproliferative effects of HSD and HST in cancer models.

RESULTS

HSD and HST have been proven to delay cell proliferation in several cancer models. Depending on the compound, dose and cell line studied, different effects have been reported. Cell cycle arrest associated with cytostatic effects has been reported in cells with increased levels of p53 and also cyclin-dependent kinase inhibitors, as well as decreased levels of specific cyclins and cyclin-dependent kinases. Moreover, apoptotic effects have been found to be associated with altered ratios of pro-/antiapoptotic proteins, caspase activation, c-Jun N-terminal kinase (JNK) pathway activation and caspase-independent pathways.

CONCLUSION

Available scientific literature data indicate complex effects, dependent on cell lines and exposure conditions, suggesting that HSD and HST doses need to be optimized according to the cellular and organismal context. The establishment of the main antiproliferative mechanisms is of utmost importance for a possible therapeutic benefit of citrus flavanones in the context of cancer.

β-Carotene and its physiological metabolites: Effects on oxidative status regulation and genotoxicity in in vitro models

Carotenoids are ubiquitously distributed in nature, β-carotene being the most frequently found carotenoid in the human diet. In the human body, β-carotene is absorbed, distributed and metabolized by enzymatic and/or non-enzymatic oxidant cleavage into several metabolites. Despite the broadly accepted biological value of β-carotene, it has also been considered a double-edged sword, mainly due to its potential antioxidant versus pro-oxidant behaviour. In this sense, the aim of this work was to scrutinize the antioxidant or pro-oxidant potential of β-carotene and its metabolites, namely trans-β-apo-8'-carotenal and β-ionone. Several parameters were evaluated in this study, viz. their effects on reactive species production, both in human whole blood and neutrophils; their effects on lipid peroxidation, in the absence and presence of peroxynitrite anion (ONOO^-) or hydrogen peroxide (H₂O₂), using a synaptosomal model; and finally, their putative genotoxic effects in the human hepatic HepG2 cell line. In general, depending on the cellular model and conditions tested, β-carotene and its metabolites revealed antioxidant effects to varying degrees without significant pro-oxidant or genotoxic effects.

Antioxidant mechanisms to counteract TiO2-nanoparticles toxicity in wheat leaves and roots are organ dependent

Nanoparticles (NP) bioactivity is under deep scrutiny. In this work, the antioxidant response to TiO₂-NP in wheat (Triticum aestivum) was determined. For that, enzymatic and the non-enzymatic antioxidants were evaluated in plants exposed to the P25 anatase:rutile material composed of TiO₂-NP and under environmentally realistic doses (0; 5; 50; 150 mg/L for 20 days). Shoot but not root growth was reduced. In leaves, thiol metabolism and ascorbate accumulation were the preferred route whereas in roots the pre-existing antioxidant capacity was preferentially utilized. Both leaves and roots showed increased glutathione reductase and dehydroascorbate reductase activities and decreased ascorbate peroxidase activity. Roots, nevertheless, presented higher enzymatic basal levels than leaves. On the other hand, when examining non-enzymatic antioxidants, the ratio of reduced-to-oxidized glutathione (GSH/GSSG) increased in leaves and decreased in roots. Exposed leaves also presented higher total ascorbate accumulation compared to roots. TiO₂-NP exposure down regulated, with more prominence in roots, antioxidant enzyme genes encoding catalase, ascorbate peroxidase, monodehydroascorbate reductase and dehydroascorbate reductase. In leaves, superoxide dismutase gene expression was increased. All data pinpoint to TiO₂-NP toxicity above 5 mg/L, with aerial parts being more susceptible, which draws concerns on the safety doses for the use of these NPs in agricultural practices.

Responses of olive plants exposed to different irrigation treatments in combination with heat shock: physiological and molecular mechanisms during exposure and recovery

A water-deficit period, leading to stomatal control and overexpression of protective proteins (sHSP and DHN), contributes to olive´s tolerance to later imposed stress episodes. Aquaporins modulation is important in olive recovery. Olive is traditionally cultivated in dry farming or in high water demanding irrigated orchards. The impact of climate change on these orchards remains to unveil, as heat and drought episodes are increasing in the Mediterranean region. To understand how young plants face such stress episodes, olive plants growing in pots were exposed to well-irrigated and non-irrigated treatments. Subsequently, plants from each treatment were either exposed to 40 °C for 2 h or remained under control temperature. After treatments, all plants were allowed to grow under well-irrigated conditions (recovery). Leaves were compared for photosynthesis, relative water content, mineral status, pigments, carbohydrates, cell membrane permeability, lipid peroxidation and expression of the protective proteins' dehydrin (OeDHN1), heat-shock proteins (OeHSP18.3), and aquaporins (OePIP1.1 and OePIP2.1). Non-irrigation, whilst increasing carbohydrates, reduced some photosynthetic parameters to values below the ones of the well-irrigated plants. However, when both groups of plants were exposed to heat, well-irrigated plants suffered more drastic decreases of net CO₂ assimilation rate and chlorophyll b than non-irrigated plants. Overall, OeDHN1 and OeHSP18.3 expression, which was increased in non-irrigated treatment, was potentiated by heat, possibly to counteract the increase of lipid peroxidation and loss of membrane integrity. Plants recovered similarly from both irrigation and temperature treatments, and recovery was associated with increased aquaporin expression in plants exposed to one type of stress (drought or heat). These data represent an important contribution for further understanding how dry-farming olive will cope with drought and heat episodes.

Biochemical and transcriptional analyses of cadmium-induced mitochondrial dysfunction and oxidative stress in human osteoblasts

Cadmium (Cd) accumulation is known to occur predominantly in kidney and liver; however, low-level long-term exposure to Cd may also result in bone damage. Few studies have addressed Cd-induced toxicity in osteoblasts, particularly upon cell mitochondrial energy processing and putative associations with oxidative stress in bone. To assess the influence of Cd treatment on mitochondrial function and oxidative status in osteoblast cells, human MG-63 cells were treated with Cd (up to 65 μM) for 24 or 48 h. Intracellular reactive oxygen species (ROS), lipid and protein oxidation and antioxidant defense mechanisms such as total antioxidant activity (TAA) and gene expression of antioxidant enzymes were analyzed. In addition, Cd-induced effects on mitochondrial function were assessed by analyzing the activity of enzymes involved in mitochondrial respiration, membrane potential (ΔΨm), mitochondrial morphology and adenylate energy charge. Treatment with Cd increased oxidative stress, concomitantly with lipid and protein oxidation. Real-time polymerase chain reaction (qRT-PCR) analyses of antioxidant genes catalase (CAT), glutathione peroxidase 1 (GPX1), glutathione S-reductase (GSR), and superoxide dismutase (SOD1 and SOD2) exhibited a trend toward decrease in transcripts in Cd-stressed cells, particularly a downregulation of GSR. Longer treatment with Cd (48 h) resulted in energy charge states significantly below those commonly observed in living cells. Mitochondrial function was affected by ΔΨm reduction. Inhibition of mitochondrial respiratory chain enzymes and citrate synthase also occurred following Cd treatment. In conclusion, Cd induced mitochondrial dysfunction which appeared to be associated with oxidative stress in human osteoblasts.

Inorganic Hg toxicity in plants: A comparison of different genotoxic parameters

Inorganic Mercury (Hg) contamination persists an environmental problem, but its cyto- and genotoxicity in plants remains yet unquantified. To determine the extent of Hg-induced cyto- and genotoxicity, and assess most sensitive endpoints in plants, Pisum sativum L. seedlings were exposed for 14 days to different HgCl2 concentrations up to 100 μM. Shoots and roots from hydroponic exposure presented growth impairment and/or morphological disorders for doses >1 μM, being the roots more sensitive. Plant growth, ploidy changes, clastogenicity (HPCV), cell cycle dynamics (G1-S-G2), Comet-tail moment (TM), Comet-TD, Mitotic-index (MI) and cell proliferation index (CPI) were used to evaluate Hg-induced cyto/genotoxicity. Both leaf and root DNA-ploidy levels, assessed by flow cytometry (FCM), remained unaltered after exposure. Root cell cycle impairment occurred at lower doses (≥1 μM) than structural DNA damages (≥10 μM). Cytostatic effects depended on the Hg concentration, with delays during S-phase at lower doses, and arrests at G1 at higher ones. This arrest was paralleled with decreases of both mitotic index (MI) and cell proliferation index (CPI). DNA fragmentation, assessed by the Comet assay parameters of TD and TM, could be visualized for conditions ≥10 μM, while FCM-clastogenic parameter (FPCV) and micronuclei (MNC) were only altered in roots exposed to 100 μM. We demonstrate that inorganic-Hg induced cytostaticity is detectable even at 1 μM (a value found in contaminated sites), while structural DNA breaks/damage are only visualized in plants at concentrations ≥10 μM. We also demonstrate that among the different techniques tested for cyto- and genotoxicity, TD and TM Comet endpoints were more sensitive than FPCV or MNC. Regarding cytostatic effects, cell cycle analysis by FCM, including the difference in % cell cycle phases and CPI were more sensitive than MI or MNC frequency. Our data contribute to better understand Hg cyto- and genotoxicity in plants and to understand the information and sensitivity provided by each of the genotoxic techniques used.

Combination of etoposide and fisetin results in anti-cancer efficiency against osteosarcoma cell models

Osteosarcoma chemotherapy is often limited by chemoresistance, resulting in poor prognosis. Combined chemotherapy could, therefore, be used to prevent resistance to chemotherapeutics. Here, the effects of fisetin on osteosarcoma cells were investigated, as well as cytostatic potential in combination with the anti-cancer drug etoposide. For this, different osteosarcoma cell lines were treated with fisetin, with etoposide and with respective combinations. Fisetin was associated with decrease in colony formation in Saos-2 and in U2OS cells but not in MG-63 cells. Notwithstanding, upon evaluation of cellular growth by crystal violet assay, MG-63 and Saos-2 cells showed decreased cell proliferation at 40 and 20 µM fisetin, respectively. Depending on the relative concentrations, fisetin:etoposide combinations showed negative-to-positive interactions on the inhibition of cell proliferation. In addition, fisetin treatment up to 50 µM for 48 h resulted in G2-phase cell cycle arrest. Regardless of the combination, fisetin:etoposide increased % cells in G2-phase and decreased % cells in G1-phase. In addition, mixtures with more positive combined effects induced increased % cells in S-phase. Compared to etoposide treatment, these combinations resulted in decreased levels of cyclins B1 and E1, pointing to the role of these regulators in fisetin-induced cell cycle arrest. In conclusion, these results show that the combination of fisetin with etoposide has higher anti-proliferative effects in osteosarcoma associated with cell cycle arrest, allowing the use of lower doses of the chemotherapeutic agent, which has important implications for osteosarcoma treatment.

Cytotoxic effect of the serotonergic drug 1-(1-Naphthyl)piperazine against melanoma cells

1-(1-Naphthyl)piperazine (1-NPZ) is a serotonergic derivative of quipazine acting both as antagonist and agonist of different serotonin receptors, with promising results for the management of skin cancer. In this work, we studied the effect of 1-NPZ on human MNT-1 melanoma cells by evaluating its effects on cell viability, ability to form colonies, cell cycle dynamics, reactive oxygen species (ROS) production and apoptosis. Treatment of MNT-1 cells with 1-NPZ for 24h decreased cell viability and induced apoptosis in a dose-dependent manner. Activity against melanoma was confirmed with a different melanoma cell line, SK-MEL-28. Simultaneously, 1-NPZ affected cell cycle progression by mediating a S-phase delay. Higher levels of ROS were also detected in MNT-1 cells after treatment with 1-NPZ. Furthermore, 1-NPZ significantly increased the expression of cyclooxygenase-2 in MNT-1 cells. These findings suggest that 1-NPZ pretreatment is able to induce oxidative stress, and consequently apoptotic cell death in melanoma cells. In conclusion, this study demonstrates the cytotoxic and genotoxic potential of 1-NPZ against melanoma cells.

Hesperetin-etoposide combinations induce cytotoxicity in U2OS cells: Implications on therapeutic developments for osteosarcoma

Osteosarcoma chemotherapy has improved survival rates, however, chemoresistance and drug toxicity still limit therapy. Drug combinations may overcome these limitations by allowing fewer chemoresistant cells to survive. The aim of this study was to evaluate the cytotoxic potential of hesperetin to osteosarcoma and to analyze the cell cycle effects of combinations of hesperetin with chemotherapeutic agents. For this, the U2OS human osteosarcoma cell line was exposed to hesperetin or hesperetin combined with etoposide or doxorubicin in defined proportions. Hesperetin was less cytotoxic compared to chemotherapeutic agents, as shown by cell growth, viability and clonogenic assays. Notwithstanding, hesperetin combined with etoposide showed additive effects on the inhibition of cell growth. Furthermore, hesperetin induced G2-phase arrest, associated with decreased gene expression of cyclins B1 and E1 and cyclin-dependent kinases 1 and 2. The combination with higher additive effect resulted in higher percentage of cells in G2-phase, showing that G2-phase arrest is associated with cytotoxicity. Moreover, hesperetin induced cytostatic effects. In conclusion, our results suggest that G2-phase arrest is an important step for hesperetin-induced cytotoxicity in U2OS cells. Hesperetin shows potential cytotoxicity when combined with etoposide, which may have implications on therapeutic developments for osteosarcoma.

Cadmium-induced genotoxicity in human osteoblast-like cells

Cadmium (Cd) is a widespread heavy metal used in numerous industrial processes. Cd exerts toxicological effects mostly in kidney and liver. Bone is also an important target of Cd, however, the cellular mechanisms of Cd toxicological effects in the bone cells are still poorly understood. Therefore, the present work aimed to investigate the putative cytotoxic and genotoxic effects of Cd to human bone cells. For that, the osteoblast-like MG-63 cells were exposed to 20 and 50μM Cd for 24 and 48h. Results showed a dose-dependent increase in Cd accumulation in cells and a decrease in cell viability, especially after 48h. Cell cycle analysis showed a delay at S phase concomitant with a decrease in cells at G0/G1 phase. After 24h, Cd treatment downregulated the expression of CHEK1, CHEK2 and CDK2 genes and upregulated the expression of CCNE1 gene. After 48h, the expression of ATM and CCNB1 genes were downregulated. Also, a 3.3 fold increase on the expression of gene CCNE1 was detected. Both Cd doses induced DNA fragmentation at 48h, while an increase in micronuclei (MN) and nucleoplasmic bridges (NPBs) together with an increase in the percentage of apoptotic/necrotic cells was detected for both time periods. Overall, our results demonstrate the cytotoxicity and genotoxicity of Cd in human bone cells. Also, the cytokinesis-block micronucleus (CBMN) assay parameters (MN, NPBs and the percentage of cells under apoptosis or necrosis) together with the cell cycle appear as the most sensitive to Cd cyto- and genotoxicity, being early affected even with the lowest Cd dose. Therefore, these cyto-/genotoxic techniques may be selected for early detection of Cd-induced toxicity.

Sulforaphane induces oxidative stress and death by p53-independent mechanism: implication of impaired glutathione recycling

Sulforaphane (SFN) is a naturally-occurring isothiocyanate best known for its role as an indirect antioxidant. Notwithstanding, in different cancer cell lines, SFN may promote the accumulation of reactive oxygen species (ROS) and cause cell death e.g. by apoptosis. Osteosarcoma often becomes chemoresistant, and new molecular targets to prevent drug resistance are needed. Here, we aimed to determine the effect of SFN on ROS levels and to identify key biomarkers leading to ROS unbalance and apoptosis in the p53-null MG-63 osteosarcoma cell line. MG-63 cells were exposed to SFN for up to 48 h. At 10 μM concentration or higher, SFN decreased cell viability, increased the%early apoptotic cells and increased caspase 3 activity. At these higher doses, SFN increased ROS levels, which correlated with apoptotic endpoints and cell viability decline. In exposed cells, gene expression analysis revealed only partial induction of phase-2 detoxification genes. More importantly, SFN inhibited ROS-scavenging enzymes and impaired glutathione recycling, as evidenced by inhibition of glutathione reductase (GR) activity and combined inhibition of glutathione peroxidase (GPx) gene expression and enzyme activity. In conclusion, SFN induced oxidative stress and apoptosis via a p53-independent mechanism. GPx expression and activity were found associated with ROS accumulation in MG-63 cells and are potential biomarkers for the efficacy of ROS-inducing agents e.g. as co-adjuvant drugs in osteosarcoma.

Proteomics of industrial fungi: trends and insights for biotechnology

Filamentous fungi are widely known for their industrial applications, namely, the production of food-processing enzymes and metabolites such as antibiotics and organic acids. In the past decade, the full genome sequencing of filamentous fungi increased the potential to predict encoded proteins enormously, namely, hydrolytic enzymes or proteins involved in the biosynthesis of metabolites of interest. The integration of genome sequence information with possible phenotypes requires, however, the knowledge of all the proteins in the cell in a system-wise manner, given by proteomics. This review summarises the progress of proteomics and its importance for the study of biotechnological processes in filamentous fungi. A major step forward in proteomics was to couple protein separation with high-resolution mass spectrometry, allowing accurate protein quantification. Despite the fact that most fungal proteomic studies have been focused on proteins from mycelial extracts, many proteins are related to processes which are compartmentalised in the fungal cell, e.g. β-lactam antibiotic production in the microbody. For the study of such processes, a targeted approach is required, e.g. by organelle proteomics. Typical workflows for sample preparation in fungal organelle proteomics are discussed, including homogenisation and sub-cellular fractionation. Finally, examples are presented of fungal organelle proteomic studies, which have enlarged the knowledge on areas of interest to biotechnology, such as protein secretion, energy production or antibiotic biosynthesis.