A proteomic investigation into the human cervical cancer cell line HeLa treated with dicitratoytterbium (III) complex

Lanthanides have been reported to induce apoptosis in cancer cell lines. Human cervical cancer cell line HeLa was found to be more sensitive to dicitratolanthanum (III) complex ([LaCit₂]³⁻) than other cancer cell lines. However, the effect and mechanism of dicitratoytterbium (III) complex ([YbCit₂]³⁻) on HeLa cells is unknown. Using biochemical and comparative proteomic analyses, [YbCit₂]³⁻ was found to inhibit HeLa cell growth and induce apoptosis. Similar to the effects of [LaCit₂]³⁻, proteomics results from [YbCit₂]³⁻-treated cells revealed profound changes in proteins relating to mitochondria and oxidative stress, suggesting that mitochondrial dysfunction plays a key role in [YbCit₂]³⁻-induced apoptosis. This was confirmed by the decreased mitochondrial transmembrane potential and the increased generation of reactive oxygen species in [YbCit₂]³⁻-treated cells. Western blot analysis showed that [YbCit₂]³⁻-induced apoptosis was accompanied by the activation of caspase-9 and specific proteolytic cleavage of PARP, leading to an increase in the pro-apoptotic protein Bax and a decrease in the anti-apoptotic protein Bcl-2. These results suggest a mitochondrial pathway of cell apoptosis in [YbCit₂]³⁻-treated cells, which will help us understand the molecular mechanisms of lanthanide-induced apoptosis in tumor cells.     

Paracrine regulation of growth factor signaling by shed leucine-rich repeats and immunoglobulin-like domains 1

Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) is a recently discovered negative regulator of growth factor signaling. The LRIG1 integral membrane protein has been demonstrated to regulate various oncogenic receptor tyrosine kinases, including epidermal growth factor (EGF) receptor (EGFR), by cell-autonomous mechanisms. Here, we investigated whether LRIG1 ectodomains were shed, and if LRIG1 could regulate cell proliferation and EGF signaling in a paracrine manner. Cells constitutively shed LRIG1 ectodomains in vitro, and shedding was modulated by known regulators of metalloproteases, including the ADAM17 specific inhibitor TAPI-2. Furthermore, shedding was enhanced by ectopic expression of Adam17. LRIG1 ectodomains appeared to be shed in vivo, as well, as demonstrated by immunoblotting of mouse and human tissue lysates. Ectopic expression of LRIG1 in lymphocytes suppressed EGF signaling in co-cultured fibroblastoid cells, demonstrating that shed LRIG1 ectodomains can function in a paracrine fashion. Purified LRIG1 ectodomains suppressed EGF signaling without any apparent downregulation of EGFR levels. Taken together, the results show that the LRIG1 ectodomain can be proteolytically shed and can function as a non-cell-autonomous regulator of growth factor signaling. Thus, LRIG1 or its ectodomain could have therapeutic potential in the treatment of growth factor receptor-dependent cancers.     

Search for human DNA topoisomerase II poisons in the group of 2,5-disubstituted-1,3,4-thiadiazoles

Abstract

A series of six 2,5-disubstituted 1,3,4-thiadiazole derivatives was synthesized and examined for cytotoxic activity in MCF-7 and MDA-MB-231 breast cancer cells. MTT assay confirmed that 2-(3-fluorophenylamino)-5-(3-hydroxyphenyl)-1,3,4-thiadiazole (2), 2-(4-bromophenylamino)-5-(2,4-dichlorophenyl)-1,3,4-thiadiazole (3), 2-(4-fluorophenylamino)-5-(2,4-dichlorophenyl)-1,3,4-thiadiazole (4), had ability to inhibit MCF-7 and MDA-MB-231 cells proliferation. The IC₅₀ values for the mentioned compounds ranged between 120 and 160?μM (with respect to MCF-7 cells) and from 70 to 170?μM (with respect to MDA-MB-231 cells). It turned out, moreover, that compound 2 is a human topoisomerase II (topoII) catalytic inhibitor whereas the two other compounds (i.e. 3 and 4) are capable of stabilizing DNA-topoII cleavage complex and thus are topoII poisons.     

Coupling of the polyamine and iron metabolism pathways in the regulation of proliferation: Mechanistic links to alterations in key polyamine biosynthetic and catabolic enzymes

Many biological processes result from the coupling of metabolic pathways. Considering this, proliferation depends on adequate iron and polyamines, and although iron-depletion impairs proliferation, the metabolic link between iron and polyamine metabolism has never been thoroughly investigated. This is important to decipher, as many disease states demonstrate co-dysregulation of iron and polyamine metabolism. Herein, for the first time, we demonstrate that cellular iron levels robustly regulate 13 polyamine pathway proteins. Seven of these were regulated in a conserved manner by iron-depletion across different cell-types, with four proteins being down-regulated (i.e., acireductone dioxygenase 1 [ADI1], methionine adenosyltransferase 2α [MAT2α], Antizyme and polyamine oxidase [PAOX]) and three proteins being up-regulated (i.e., S-adenosyl methionine decarboxylase [AMD1], Antizyme inhibitor 1 [AZIN1] and spermidine/spermine-N¹-acetyltransferase 1 [SAT1]). Depletion of iron also markedly decreased polyamine pools (i.e., spermidine and/or spermine, but not putrescine). Accordingly, iron-depletion also decreased S-adenosylmethionine that is essential for spermidine/spermine biosynthesis. Iron-depletion additionally reduced ³H-spermidine uptake in direct agreement with the lowered levels of the polyamine importer, SLC22A16. Regarding mechanism, the “reprogramming” of polyamine metabolism by iron-depletion is consistent with the down-regulation of ADI1 and MAT2α, and the up-regulation of SAT1. Moreover, changes in ADI1 (biosynthetic) and SAT1 (catabolic) partially depended on the iron-regulated changes in c-Myc and/or p53. The ability of iron chelators to inhibit proliferation was rescuable by putrescine and spermidine, and under some conditions by spermine. Collectively, iron and polyamine metabolism are intimately coupled, which has significant ramifications for understanding the integrated role of iron and polyamine metabolism in proliferation.     

Neuroendocrine differentiation contributes to radioresistance development and metastatic potential increase in non-small cell lung cancer

Radiation treatment induces neuroendocrine differentiation (NED) in non-small cell lung cancer (NSCLC) A549 and H157 cells, so higher NE-like features in radioresistant A549 (A549R26-1) and H157 (H157R24-1) cells are observed than in parental cells. We detected higher NED marker expressions in A549R26-1 cell-derived tumors than in A549 cell-derived tumors. In mechanism studies, we found that NED induction in A549R26-1 and H157R24-1 cells was accompanied by increased intracellular cAMP and IL-6 levels. Treatment of radioresistant lung cancer cells with the inhibitor (SQ22536) of adenylate cyclase (AC) which is the enzyme responsible for the cAMP production, or the neutralizing antibody (Ab) of IL-6, resulted in decreased NE-like features in radioresistant lung cancer cells. In addition, we found MEK/Erk is the signaling pathway that triggers the cAMP- and IL-6-mediated NED induction in radioresistant lung cancer cells. Also, we found that MEK/Erk signaling pathway inhibition decreased NED in radioresistant cells. Radioresistant lung cancer cells exhibiting high NE-like features also showed higher radioresistance and higher metastatic potential than parental cells. When we inhibited cAMP-, or IL-6-mediated pathways, or the downstream MEK/Erk signaling pathway, radiosensitivity of radioresistant lung cancer cells was significantly increased and their metastatic potential was significantly reduced. In in vivo mouse studies, reducing NED by treating mice with the MEK/Erk inhibitor increased radiosensitivity. Immunohistochemical staining of tumor tissues lowered expressions of the NED/epithelial-mesenchymal transition (EMT)/metastatic markers when mice were treated with the MEK/Erk inhibitor.     

In vitro and in vivo anti-inflammatory properties of imine resveratrol analogues

Resveratrol is a natural polyphenol found mainly on red grapes and in red wine, pointed as an important anti-inflammatory/immunomodulatory molecule. However, its bioavailability problems have limited its use encouraging the search for new alternatives agents. Thus, in this study, we synthetize 12 resveratrol analogues (6 imines, 1 thioimine and 5 hydrazones) and investigated its cytotoxicity, antioxidant activity and in vitro anti-inflammatory/immunomodulatory properties. The most promising compounds were also evaluated in vivo. The results showed that imines presented less cytotoxicity, were more effective than resveratrol on DPPH scavenger and exhibited an anti-inflammatory profile. Among them, the imines with a radical in the para position, on the ring B, not engaged in an intramolecular hydrogen-interaction, showed more prominent anti-inflammatory activity modulating, in vivo, the edema formation, the inflammatory infiltration and cytokine levels. An immunomodulatory activity also was observed in these molecules. Thus, our results suggest that imines with these characteristics presents potential to control inflammatory disorders.     

Pharmacotoxicological applications of an equivalent dermis: three measurements of cytotoxicity

The legal procedure for evaluating the toxicity of cosmetic, household, chemical and pharmaceutical products is still the irritancy Draize test on rabbits. Various irritation tests are currently being developed as alternatives toin vivo animal testing. Ourin vitro model system is composed of 24 equivalent dermis (ED) comprising a chitosan-cross-linked collagen-glycosaminoglycan matrix populated by foreskin fibroblasts. In evaluating this system for irritancy testing, three different measures of toxicity were used: MTT (dimethylthiazol diphenyltetrazolium bromide) reduction, and lactate dehydrogenase and interleukin-6 release. The experiments described herein represent a preliminary evaluation to determine the usefulness and predictive value of our 24 ED kit as an alternative method for the prediction of human dermal reaction, versus three chemical products: cadmium chloride, lauryl sulfate, and benzalkonium chloride. Preliminary results suggest that the ED may be a usefulin vitro model for the prediction of cutaneous and ocular toxicity and allow the development of a 24-skin-equivalent kit realized by seeding human normal keratinocytes onto the equivalent dermis.Abbreviations ED equivalent dermis - ECM extracellular matrix - FCM fibroblast culture medium - LDH lactate dehydrogenase - IL-6 interleukin-6 - MTT dimethylthiazol diphenyltetrazolium bromide     

Evaluation of Antiherpetic Compounds Using a Gastric Cancer Cell Line: Pronounced Activity of BVDU against Herpes Simplex Virus Replication

We developed a rapid and simple method for the screening of antiviral agents against herpes simplex virus (HSV) in a model of gastrointestinal herpetic infection in vitro. This method was based on inhibition of HSV-induced cytopathogenicity in gastric adenocarcinoma MKN-28 cells, as monitored by an MTT colorimetric assay. From the various compounds that were evaluated for their activity against HSV-1 and HSV-2, brivudine (BVDU) emerged as the most effective. When the 50% effective concentration (EC₅₀) values of the antiherpes agents in MKN-28 cells were compared with those in human embryo lung MRC-5 cells, all compounds, except for BVDU, showed higher EC₅₀ values in MKN-28 cells. For BVDU the EC₅₀ values in MKN-28 cells were 0.8 (HSV-1) and 0.036 (HSV-2) times the EC₅₀ values in MRC-5 cells. Thus BVDU was 27.5 times more active against HSV-2 in MKN-28 cells than in MRC-5 cells. The MKN-28 gastric cancer cells may be useful for the rapid screening of anti-HSV agents and, in particular, those that may be useful in therapy of gastrointestinal HSV infections in gastrointestinal herpetic infection.     

Partial purification and characterization of bacteriocin produced by Enterococcus faecalis DU10 and its probiotic attributes

A novel bacteriocin produced by avian duck isolated lactic acid bacterium Enterococcus faecalis DU10 was isolated. This bacteriocin showed a broad spectrum of antibacterial activity against important food-borne pathogens and was purified by size exclusion chromatography followed by reverse-phase high-performance liquid chromatography in a C-18 column. Tricine–SDS PAGE revealed the presence of a band with an estimated molecular mass of 6.3?kDa. The zymogram clearly linked the antimicrobial activity with this band. This result was further confirmed by mass-assisted laser desorption ionization time-of-flight mass spectrometry, since a sharp peak corresponding to 6.313?kDa was detected and the functional groups were revealed by Fourier transform infrared spectroscopy. Bacteriocin DU10 activity was found sensitive to proteinase-K and pepsin and partially affected by trypsin and α-chymotrypsin. The activity of bacteriocin DU10 was partially resistant to heat treatments ranging from 30 to 90°C for 30?min. It also withstood a treatment at 121°C for 10?min. Cytotoxicity of bacteriocin DU10 by methyl-thiazolyl-diphenyl-tetrazolium bromide assay showed that the viability of HT-29 and HeLa cells decreased 60?±?0.7% and 43?±?4.8%, respectively, in the presence of 3,200?AU/mL of bacteriocin. The strain withstood 0.3% w/v of bile oxgall and pH 2 affected the bacterial growth between 2 and 4?hr of incubation. Adhesion properties examined with HT-29 cell line showed 69.85% initial population of strain E. faecalis DU10, which was found to be strongly adhered to this cell line. These results conclude bacteriocin DU10 may be used as a potential biopreservative and E. faecalis DU10 may be used as a potential probiont to control Salmonella infections.     

Protective effect of Bosutinib with caspase inhibitors on human K562 cells

IntroductionCancer therapy has become increasingly focused on molecularly targeted medications. Despite the fact that multi-cytotoxic medication regimens have proven to be highly effective, many investigations in targeted treatments have focused on a single agent. The precise molecular mechanism of action of second-generation BCR–ABL tyrosine kinase inhibitors, which includes different targets and pathways, can help rationalize therapy in chronic myelogenous leukemia (CML) and other diseases affected by BCR–ABL tyrosine kinase inhibitors (TKIs).AimThe purpose of this study was to analyze if bosutinib (BOS) combined with Boc-D-FMK effectively suppressed proliferation and induced apoptosis in K562 cells to a lesser extent, implying that bosutinib is an effective leukemia treatment and that its combination with Boc-D-FMK is a mild chemotherapeutic agent against leukemia.MethodsIn this study, bosutinib was obtained together with other materials to perform a cell culture experiment with human cell lines, as well as additional drug treatment. Furthermore, cell viability (MTT assay) and flow cryometry such as viability and cell cycle assays are performed. The target profile of the dual SRC/ABL inhibitor bosutinib was studied in this study as a first kinase inhibitor to target K562 cells, which has recently been linked to the proliferation of myelogenous leukaemia cells, these results suggest the effectiveness of inhibitory activity on cell viability/proliferation, alone generated a potent value of 250 nM (39.27 ± 1.17) for 48 h as optimal dose.ResultsThe cytotoxic effect of bosutinib on the K562 cell line was assessed in vitro using the MTT assay, and the cytotoxicity was further clarified using cell viability and cell cycle assays. Guava Cell Assay software validated the activation of apoptosis. Sub-G1, G0/G1, S, and G2/M phases are depicted. Cell cycle research revealed that K562 cells treated with bosutinib accumulated much more in the sub-G1 phase, which was later validated by a drop peak at the G2/M phase.ConclusionIn conclusion, the nature of bosutinib's reduction of cancer cell growth may open the door to future research into the development of green synthesis medicines, particularly for cancer treatment.