Coralia Bleotu

Therapies targeting cancer stem cells: Current trends and future challenges

Traditional therapies against cancer, chemo- and radiotherapy, have multiple limitations that lead to treatment failure and cancer recurrence. These limitations are related to systemic and local toxicity, while treatment failure and cancer relapse are due to drug resistance and self-renewal, properties of a small population of tumor cells called cancer stem cells (CSCs). These cells are involved in cancer initiation, maintenance, metastasis and recurrence. Therefore, in order to develop efficient treatments that can induce a long-lasting clinical response preventing tumor relapse it is important to develop drugs that can specifically target and eliminate CSCs. Recent identification of surface markers and understanding of molecular feature associated with CSC phenotype helped with the design of effective treatments. In this review we discuss targeting surface biomarkers, signaling pathways that regulate CSCs self-renewal and differentiation, drug-efflux pumps involved in apoptosis resistance, microenvironmental signals that sustain CSCs growth, manipulation of miRNA expression, and induction of CSCs apoptosis and differentiation, with specific aim to hamper CSCs regeneration and cancer relapse. Some of these agents are under evaluation in preclinical and clinical studies, most of them for using in combination with traditional therapies. The combined therapy using conventional anticancer drugs with CSCs-targeting agents, may offer a promising strategy for management and eradication of different types of cancers.

In vitro hepatic differentiation of human bone marrow mesenchymal stem cells under differential exposure to liver-specific factors.

Recent findings demonstrated that stem cells could be harvested from a patient and used to repair his or her own damaged liver. Additionally, stem cells may be manipulated in vitro to induce hepatic differentiation. The current study aims to determine the differentiation efficacy of various liver-specific factors (hepatocyte growth factor, Insulin-Transferrin-Selenium, dexamethasone, and nicotinamide) used for stem cell differentiation into hepatocyte-like cells. Human mesenchymal stem cells were exposed to different media containing these compounds added individually or in various combinations. Hepatic differentiation was assessed via quantitative reverse transcription-polymerase chain reaction and immunocytochemical staining for stemness or liver-specific genes and proteins, including albumin, cytokeratins 18 and 19, HepPar-1, alpha-fetoprotein, and nestin. In addition, functional tests for glycogen storage, urea production, glucose, and albumin synthesis were also performed. The expression profiles of albumin, alpha-fetoprotein, and cytokeratin 19 demonstrated that when hepatocyte growth factor, nicotinamide, or dexamethasone were added individually, incomplete hepatocyte differentiation was achieved; the obtained cell populations contained progenitors that expressed both hepatic (albumin) and biliary (cytokeratin 19) markers, as well as alpha-fetoprotein. Hepatocyte growth factor and nicotinamide were the factors with the most hepatogenic potential. When all factors were added to the culture, cells exhibited features that closely resembled human adult hepatocytes as determined by their gene expression patterns (albumin, HepPar-1, and alpha-fetoprotein, but not cytokeratin 19) and functional testing. These cells with hepatic function may become important tools for liver transplant procedures, liver development studies, and pharmacologic research.

IL-17 in cutaneous lupus erythematosus.

BACKGROUND Lupus erythematosus (LE) is a heterogeneous disease with broad clinical spectrum from cutaneous to visceral and systemic inflammation. IL-17 isoforms (IL-17A and IL-17F) are proinflammatory cytokines with unclear implications in lupus erythematosus pathogenesis. In this study we focused upon IL-17 in normal and modified lupus skin with a correlative study between local and serological expression. MATERIAL AND METHODS 89 subjects were recruited and divided in 5 groups-10 patients with psoriasis (disease control group), 13 healthy controls, 26 with discoid chronic lupus (DLE), 23 with systemic lupus erythematosus (SLE) and 17 with subacute lupus erythematosus (SCLE). Blood samples and skin punched-biopsy specimens were performed. Serum IL-17A, IL-17F, and IL-23 concentrations were determined by ELISA. Skin IL-17A and CD4 expression were evaluated by immunohistochemistry. RESULTS Immunohistochemical expression of IL-17A was higher in DLE, SCLE and SLE patients than in negative control subjects (all p<0.05). Serum IL-17A concentrations were higher in DLE and SLE patients than in negative controls (p<0.05). Serum IL-17A levels were similar in SCLE and negative controls (p>0.05). Serum IL-17F concentrations were higher in DLE, SCLE and SLE patients than in healthy controls (all p<0.05). In DLE, SCLE, SLE patients and healthy controls we observed comparable levels of IL-23 (p>0.05). Serum anti Ro antibodies correlate with IL-17A+ lymphocytes from SCLE lesion and SLE normal skin (all p<0.05). CONCLUSION IL-17 isoforms (IL-17A and IL-17F) are implicated in SLE but also in DLE and SCLE immunopathogenesis.

Prospects for new antimicrobials based on N,N-dimethylbiguanide complexes as effective agents on both planktonic and adhered microbial strains.

Metal-free N,N-dimethylbiguanidium acetate and novel complexes M(DMBG)(2)(CH(3)COO)(2).nH(2)O (M: Mn(II), Ni(II), Cu(II) and Zn(II)) were screened for their antimicrobial properties against Gram-positive (Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus), Gram-negative (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa) bacteria and fungal (Candida albicans) strains. The ability of compounds to inhibit the microbial adherence ability to the inert substratum as well as their cytotoxicity was also assessed. Our results are demonstrating that some of the tested compounds are exhibiting potent antimicrobial activity accompanied by low cytotoxicity on HeLa cells. The complexes were characterized using microanalytical, IR, EPR, (1)H NMR as well as UV-vis methods. The redox behaviour of complexes was investigated by cyclic voltammetry. The new derivative (HDMBG)(CH(3)COO) crystallizes in the monoclinic P2(1)/n space group as X-ray single-crystal data indicate.

The epithelial to mesenchymal transition in pancreatic cancer: A systematic review

BACKGROUND/OBJECTIVES The present article summarizes and analyzes the current knowledge about the role of the epithelial to mesenchymal transition (EMT) in the systemic invasiveness of pancreatic cancer. METHOD An electronic search of PubMed/MEDLINE, EMBASE, and the Web of Science was used to identify relevant original articles and reviews. RESULTS The EMT represents a key step during normal embryogenesis. However, increasing evidence reveals its essential role in the local progression and metastasis of pancreatic cancer. Areas of interest are the cross-linking between cells undergoing the EMT and pancreatic cancer stem cells, and the correlation between the EMT and chemoresistance to standard therapies. During carcinogenesis, malignant pancreatic cells at the primary site acquire the ability to undergo the EMT, a transformation associated with increased mobility. The reverse process at secondary sites, the mesenchymal to epithelial transition (MET), has devastating consequences, allowing neoplastic epithelial cells to invade surrounding tissues and spread to distant sites. Consequences of the EMT are the loss of E-cadherin expression and the acquisition of mesenchymal markers including fibronectin or vimentin. Detailed knowledge of the molecular processes underlying the EMT has opened possibilities for new therapeutic agents. These include an EMT approach for patients with early cancers, to prevent invasion and dissemination, and anti-MET therapy for patients with established metastasis. CONCLUSIONS The current literature shows a strong correlation between the EMT and the systemic aggressiveness of pancreatic tumors. Individualized therapy, targeting the process of EMT and its cross-linking with cancer stem cells, may increase survival of patients with pancreatic cancer.

Synthesis, characterization and in vitro assessment of the magnetic chitosan–carboxymethylcellulose biocomposite interactions with the prokaryotic and eukaryotic cells

Preparation and characterization of CS/Fe(3)O(4)/CMC composite scaffolds including the morphology, crystallinity, and the in vitro efficacy as antibiotic delivery vehicles as well as their influence on the eukaryotic cells are reported. The results demonstrated that the magnetic polymeric composite scaffolds are exhibiting structural and functional properties that recommend them for further applications in the biomedical field. They improve the activity of currently used antibiotics belonging to penicillins, macrolides, aminoglycosides, rifampicines and quinolones classes, representing potential macromolecular carriers for these antimicrobial substances, to achieve extracellular and intracellular targets. The obtained systems are not cytotoxic and do not influence the eukaryotic HCT8 cell cycle, representing potential tools for the delivery of drugs in a safe, effective and less expensive manner.

Biocompatible Fe3O4 increases the efficacy of amoxicillin delivery against Gram-positive and Gram-negative bacteria.

This paper reports the synthesis and characterization of amoxicillin- functionalized magnetite nanostructures (Fe3O4@AMO), revealing and discussing several biomedical applications of these nanomaterials. Our results proved that 10 nm Fe3O4@AMO nanoparticles does not alter the normal cell cycle progression of cultured diploid cells, and an in vivo murine model confirms that the nanostructures disperse through the host body and tend to localize in particular sites and organs. The nanoparticles were found clustered especially in the lungs, kidneys and spleen, next to the blood vessels at this level, while being totally absent in the brain and liver, suggesting that they are circulated through the blood flow and have low toxicity. Fe3O4@AMO has the ability to be easily circulated through the body and optimizations may be done so these nanostructures cluster to a specific target region. Functionalized magnetite nanostructures proved a great antimicrobial effect, being active against both the Gram positive pathogen S. aureus and the Gram negative pathogen E. coli. The fabricated nanostructures significantly reduced the minimum inhibitory concentration (MIC) of the active drug. This result has a great practical relevance, since the functionalized nanostructures may be used for decreasing the therapeutic doses which usually manifest great severe side effects, when administrated in high doses. Fe3O4@AMO represents also a suitable approach for the development of new alternative strategies for improving the activity of therapeutic agents by targeted delivery and controlled release.

N,N-dimethylbiguanide complexes displaying low cytotoxicity as potential large spectrum antimicrobial agents.

The new complexes M(DMBG)(2)(ClO(4))(2) (M:Mn, Ni, Cu and Zn; DMBG: N,N-dimethylbiguanide) have been synthesized and characterized by IR, EPR, (1)H NMR, (13)C NMR as well as electronic spectroscopy data. Complex [Ni(DMBG)(2)](ClO(4))(2).2DMF (DMF: N,N-dimethylformamide) crystallizes in the monoclinic P2(1)/c space group while [Cu(DMBG)(2)](ClO(4))(2) adopt monoclinic P21/c space group as X-ray single crystal data indicate. The redox behavior of complexes was investigated by cyclic voltammetry. The metal-free N,N-dimethylbiguanide and complexes exhibit specific anti-infective properties as demonstrated the low MIC values, a large antimicrobial spectrum and also inhibit the ability of Pseudomonas aeruginosa and Staphylococcus aureus strains to colonize the inert surfaces. The complexes exhibit also a low cytotoxicity levels on HeLa cells.

Usnic acid-loaded biocompatible magnetic PLGA-PVA microsphere thin films fabricated by MAPLE with increased resistance to staphylococcal colonization

Due to their persistence and resistance to the current therapeutic approaches, Staphylococcus aureus biofilm-associated infections represent a major cause of morbidity and mortality in the hospital environment. Since (+)-usnic acid (UA), a secondary lichen metabolite, possesses antimicrobial activity against Gram-positive cocci, including S. aureus, the aim of this study was to load magnetic polylactic-co-glycolic acid-polyvinyl alcohol (PLGA-PVA) microspheres with UA, then to obtain thin coatings using matrix-assisted pulsed laser evaporation and to quantitatively assess the capacity of the bio-nano-active modified surface to control biofilm formation by S. aureus, using a culture-based assay. The UA-loaded microspheres inhibited both the initial attachment of S. aureus to the coated surfaces, as well as the development of mature biofilms. In vitro bioevalution tests performed on the fabricated thin films revealed great biocompatibility, which may endorse them as competitive candidates for the development of improved non-toxic surfaces resistant to S. aureus colonization and as scaffolds for stem cell cultivation and tissue engineering.

Magnetic Properties and Biological Activity Evaluation of Iron Oxide Nanoparticles

The aim of this study was to provide information about the biological properties of iron oxide nanoparticles (IO-NPs) obtained in an aqueous suspension. The IO-NPs were characterized by transmission electron microscopy (TEM). Analysis of hysteresis loops data at room temperature for magnetic IO-NPs sample indicated that the IO-NPs were superparamagnetic at room temperature. The calculated saturation magnetization for magnetic iron oxide was = 18.1 emu/g. The antimicrobial activity of the obtained PMC-NPs was tested against Gram-negative (Pseudomonas aeruginosa 1397, Escherichia coli ATCC 25922), Gram-positive (Enterococcus faecalis ATCC 29212, Bacillus subtilis IC 12488) bacterial as well as fungal (Candida krusei 963) strains. The obtained results suggested that the antimicrobial activity of IO-NPs is dependent on the metallic ions concentrations and on the microbial growth state, either planktonic or adherent. The obtained IO-NPs exhibited no cytotoxic effect on HeLa cells at the active antimicrobial concentrations.