The Effect of Photosensitizer Metalation Incorporated into Arene-Ruthenium Assemblies on Prostate Cancer.

Prostate cancer is the second most common cancer for men and a major health issue. Despite treatments, a lot of side effects are observed. Photodynamic therapy is a non-invasive method that uses photosensitizers and light to induce cell death through the intramolecular generation of reactive oxygen species, having almost no side effects. However, some of the PSs used in PDT show inherent low solubility in biological media, and accordingly, functionalization or vectorization is needed to ensure internalization. To this end, we have used arene-ruthenium cages in order to deliver PSs to cancer cells. These metalla-assemblies can host PSs inside their cavity or be constructed with PS building blocks. In this study, we wanted to determine if the addition of metals (Mg, Co, Zn) in the center of these PSs plays a role. Our results show that most of the compounds induce cytotoxic effects on DU 145 and PC-3 human prostate cancer cells. Localization by fluorescence confirms the internalization of the assemblies in the cytoplasm. An analysis of apoptotic processes shows a cleavage of pro-caspase-3 and poly-ADP-ribose polymerase, thus leading to a strong induction of DNA fragmentation. Finally, the presence of metals in the PS decreases PDT's effect and can even annihilate it.

Dimethyl Sulfoxide: A Bio-Friendly or Bio-Hazard Chemical? The Effect of DMSO in Human Fibroblast-like Synoviocytes.

The effect of dimethyl sulfoxide (DMSO) in rheumatoid arthritis (RA) human fibroblast-like synoviocytes (FLSs) has been studied on five different samples harvested from the joints (fingers, hands and pelvis) of five women with RA. At high concentrations (>5%), the presence of DMSO induces the cleavage of caspase-3 and PARP-1, two phenomena associated with the cell death mechanism. Even at a 0.5% concentration of DMSO, MTT assays show a strong toxicity after 24 h exposure (≈25% cell death). Therefore, to ensure a minimum impact of DMSO on RA FLSs, our study shows that the concentration of DMSO has to be below 0.05% to be considered safe.

Ruthenium-based assemblies incorporating tetrapyridylporphyrin panels: a photosensitizer delivery strategy for the treatment of rheumatoid arthritis by photodynamic therapy.

Ruthenium-based assemblies containing tetrapyridylporphyrins (TPyP) in their structure have been evaluated as photosensitizers (PS) to treat rheumatoid arthritis (RA) by photodynamic therapy (PDT). TPyP is useless by itself as a PS due to its low solubility in biological media, however, incorporated in metallacages it can be internalized in cells. The study shows a cellular antiproliferative activity in fibroblast-like synoviocyte (FLS) in the lower nanomolar range in the presence of light, and no dark toxicity at 1 µM concentration, thus having an excellent photoactivity index. The presence of diamagnetic (Zn2+) and paramagnetic (Co2+) metals in the center of TPyP impairs the effectiveness of PDT, showing no (Co) or reduced (Zn) photoactivity. A total of five metallacages with different structural characteristics have been evaluated, and our results suggest that the incorporation of PS in metalla-assemblies is not only an elegant method to increase solubility in biological media for TPyP but also appears to be an efficient hybrid system to treat RA by PDT.

ST3GAL2 knock-down decreases tumoral character of colorectal cancer cells in vitro and in vivo.

Tumor cells have a modified glycosylation profile that promotes their evolution and/or their maintenance in the tumor. Sialylation is a type of glycosylation that is often altered in cancers. RNA-Seq database analysis revealed that the sialyltransferase gene ST3GAL2 is significantly overexpressed at all stages of colorectal cancer (CRC). ST3GAL2 sialylates both glycoproteins and glycolipids. The aim of this work was to investigate the involvement of ST3GAL2 in CRC. Using the HT29 tumor cell line derived from a stage II of CRC, we decreased the expression of ST3GAL2 by specific shRNA, and then characterized these cells by performing functional tests. We found that ST3GAL2 knock down (KD) significantly decreases tumor cell proliferation, cell migration and invasiveness properties in vitro. The cell cycle of these cells is affected with a change in cell cycle distribution and an increase of cell apoptosis. The effect of ST3GAL2 KD was then studied in vivo, following xenografts into nude mice, in which the tumor progression was significantly reduced. This work demonstrates that ST3GAL2 is a major player in the behavior of colorectal tumor cells, by modifying the sialylation state of glycoproteins and glycolipids which remain to be specifically identified.

Evaluation of Ruthenium-Based Assemblies as Carriers of Photosensitizers to Treat Rheumatoid Arthritis by Photodynamic Therapy.

For the first time, ruthenium-based assemblies have been used as carriers for photosensitizers in the treatment of rheumatoid arthritis by photodynamic therapy (PDT). These metallacages are totally soluble in physiological media and can transport photosensitizers (PS) in their cavity. After an incubation period, the PS is released in the cytoplasm and irradiation can take place. This strategy allows photosensitizers with low or null solubility in biological media to be evaluated as PDT agents in rheumatoid arthritis. The systems in which 21H,23H-porphine and 29H,31H-phthalocyanine are encapsulated show excellent photocytotoxicity and no toxicity in the dark. On the other hand, systems in which metalated derivatives such as Mg(II)-porphine and Zn(II)-phthalocyanine are used show good photocytotoxicity, but to a lesser extent than the previous two. Furthermore, the presence of Zn(II)-phthalocyanine significantly increases the toxicity of the system. Overall, fifteen different host-guest systems have been evaluated, and based on the results obtained, they show high potential for treating rheumatoid arthritis by PDT.

Involvement of autophagy in diosgenin­induced megakaryocyte differentiation in human erythroleukemia cells.

Natural agents have been used to restart the process of differentiation that is inhibited during leukemic transformation of hematopoietic stem or progenitor cells. Autophagy is a housekeeping pathway that maintains cell homeostasis against stress by recycling macromolecules and organelles and plays an important role in cell differentiation. In the present study, an experimental model was established to investigate the involvement of autophagy in the megakaryocyte differentiation of human erythroleukemia (HEL) cells induced by diosgenin [also known as (25R)­Spirosten­5­en­3b­ol]. It was demonstrated that Atg7 expression was upregulated from day 1 of diosgenin­induced differentiation and was accompanied by a significant elevation in the conversion of light chain 3 A/B (LC3­A/B)­I to LC3­A/B­II. Autophagy was modulated before or after the induction of megakaryocyte differentiation using 3­methyladenine (3­MA, autophagy inhibitor) and metformin (Met, autophagy initiation activator). 3­MA induced a significant accumulation of the LC3 A/B­II form at day 8 of differentiation. It was revealed that 3­MA had a significant repressive effect on the nuclear (polyploidization) and membrane glycoprotein V [(GpV) expression] maturation. On the other hand, autophagy activation increased GpV genomic expression, but did not change the nuclear maturation profile after HEL cells treatment with Met. It was concluded that autophagy inhibition had a more prominent effect on the diosgenin­differentiated cells than autophagy activation.

Ibuprofen-loaded calcium phosphate granules: A new bone substitute for local relieving symptoms of osteoarthritis.

Musculoskeletal diseases often demand a drug treatment at the specific site of injury or defect site. In this context, the use of calcium phosphates is attractive as it allows both the bone substitution and the local delivery of a drug substance. In this work, we present a drug delivery device that combines calcium phosphate bioceramic granules and ibuprofen, a widely used anti-inflammatory drug. After verifying in vitro biocompatibility of the ibuprofen-loaded calcium phosphate granules on murine preosteoblastic cells (MC3T3), we evaluated in vitro efficiency of the drug substance released from the bioceramic using rheumatoid arthritis synoviocytes. Our data document that ibuprofen-loaded calcium phosphate granules reduced inflammatory response and increased apoptosis of synoviocytes. In vivo study showed that both unloaded, and ibuprofen-loaded calcium phosphate granules induced a progressive osteogenesis, but in the case of ibuprofen-loaded implants, bone ingrowth was more limited in first weeks. However, as far as concerns inflammation, while unloaded granules showed inflammation up to 4 weeks, ibuprofen loaded granules did not show any significant inflammation. Ibuprofen concentration determination in blood samples showed that a very small amount of the drug reached the general circulation which render this drug delivery system suitable for both bone substitution and reduction of inflammation at the implantation site. Thus, this new drug carrier could be used to locally relieve inflammatory bone diseases symptoms including rheumatoid arthritis but, beyond this study, this kind of granules could be considered for the delivery of therapeutic agents such as antibiotic, analgesic or anticancer drugs.

Metformin and Probiotics in the Crosstalk between Colitis-Associated Colorectal Cancer and Diabetes in Mice.

The co-occurrence of colorectal cancer (CRC) and diabetes mellitus along with inflammation and dismicrobism has been frequently reported. Several studies shed light on the antioncogenic potential of metformin on colorectal carcinogenesis. This study aimed to demonstrate that metformin in association with probiotics acts in a synergic effect in breaking the crosstalk, thus inhibiting CRC progression, improving diabetes, and reducing inflammation. Ninety-six male Balb/c mice, 6-8 weeks old, were divided into 16 control and experimental groups to assess the effect of the different treatments and combinations at the clinical, histological, and molecular levels. Metformin and probiotics showed beneficial outcomes on CRC and diabetes, alone and most importantly in combination. Their effects were exerted by inhibiting the inflammatory process whereby a downregulation of IL-6 and TNF-α as well as oxidative stress were depicted. The characterization of the effects of probiotics and metformin on CRC and diabetes sheds light on the role of inflammation and microbiota in this crosstalk. Deciphering the downstream signaling pathways elicited by these compounds will help in developing new effective targeted treatment modalities.

Growth Inhibitory and Pro-Apoptotic Effects of Ornamental Pomegranate Extracts in Du145 Human Prostate Cancer Cells.

Aims: Prostate cancer is the most common form of cancer in the male. Epidemiological studies have associated increased cancer incidence with reduced consumption of fruit and vegetables. This study was aimed to investigate the influence of dwarf pomegranate extracts (peel, juice, and seeds oil) on the proliferation and apoptosis of human prostate androgen-independent cell line DU145. Methods: The cell viability was determined by the MTT assay. Morphological changes are detected by light microscopy. The ELISA assay is used to evaluate the nuclear DNA fragmentation and western Blot to detect the expression of apoptosis-associated proteins including poly-ADP-ribose polymerase (PARP) and cyclooxygenase-2 (COX-2). Results: The three tested extracts exhibited a dose-response cytotoxic effect and antiproliferative action on DU145 cell line and induce morphological changes. The dose of each extract required to inhibit cell proliferation by 50% (IC50) was 0.12, 0.36, and 0.42 mg/mL, respectively, for seeds oil, juice, and peel. The three extracts could also induce prostate cancer cell apoptosis by an increase of DNA fragmentation, PARP cleavage, and inhibition of the COX-2 expression. The strongest pro-apoptotic effect was shown after peel treatment. Conclusion: Dwarf pomegranate extracts exhibited potent growth inhibitory activities in human prostate cancer cells (DU145), which appear to be mediated by a pro-apoptotic mechanism.

Photodynamic Therapy Activity of New Porphyrin-Xylan-Coated Silica Nanoparticles in Human Colorectal Cancer.

Photodynamic therapy (PDT) using porphyrins has been approved for treatment of several solid tumors due to the generation of cytotoxic reactive oxygen species (ROS). However, low physiological solubility and lack of selectivity towards tumor sites are the main limitations of their clinical use. Nanoparticles are able to spontaneously accumulate in solid tumors through an enhanced permeability and retention (EPR) effect due to leaky vasculature, poor lymphatic drainage, and increased vessel permeability. Herein, we proved the added value of nanoparticle vectorization on anticancer efficacy and tumor-targeting by 5-(4-hydroxyphenyl)-10,15,20-triphenylporphyrin (TPPOH). Using 80 nm silica nanoparticles (SNPs) coated with xylan-TPPOH conjugate (TPPOH-X), we first showed very significant phototoxic effects of TPPOH-X SNPs mediated by post-PDT ROS generation and stronger cell uptake in human colorectal cancer cell lines compared to free TPPOH. Additionally, we demonstrated apoptotic cell death induced by TPPOH-X SNPs-PDT and the interest of autophagy inhibition to increase anticancer efficacy. Finally, we highlighted in vivo, without toxicity, elevated anticancer efficacy of TPPOH-X SNPs through improvement of tumor-targeting compared to a free TPPOH protocol. Our work demonstrated for the first time the strong anticancer efficacy of TPPOH in vitro and in vivo and the merit of SNPs vectorization.

Photosensitizers Used in the Photodynamic Therapy of Rheumatoid Arthritis.

Photodynamic Therapy (PDT) has become one of the most promising treatment against autoimmune diseases, such as rheumatoid arthritis (RA), as well as in the treatment of different types of cancer, since it is a non-invasive method and easy to carry out. The three main ingredients of PDT are light irradiation, oxygen, and a photosensitizer (PS). Light irradiation depends on the type of molecule or compound to be used as a PS. The concentration of O2 fluctuates according to the medium where the target tissue is located and over time, although it is known that it is possible to provide oxygenated species to the treated area through the PS itself. Finally, each PS has its own characteristics, the efficacy of which depends on multiple factors, such as solubility, administration technique, retention time, stability, excitation wavelength, biocompatibility, and clearance, among others. Therefore, it is essential to have a thorough knowledge of the disease to select the best PS for a specific target, such as RA. In this review we will present the PSs used in the last three decades to treat RA under PDT protocol, as well as insights on the relevant strategies.

In vitro anticancer activity of new gold(III) porphyrin complexes in colon cancer cells.

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide. The limitations of cisplatin-based chemotherapy have prompted intense interest among scientists to search for alternative metal-based anticancer medicines. Gold(III) complexes have been among the most widely investigated since they showed higher cytotoxicity than cisplatin and promising in vitro and in vivo anticancer activities in CRC but their clinical usefulness has been limited by their poor stability under physiological conditions. A novel gold(III) porphyrin complexes [gold(III) porphyrin-adamantane chloride (SN1) and gold(III) porphyrin mono-acetate chloride (SN2)] with improved aqueous stability were synthesized. SN1 and SN2 reduced the survival of human CRC HT-29 and HCT-116 cell lines, caused cell cycle arrest in G2/M phase, and we observed downregulation of the expression of cyclin B1 and cyclin-dependent kinase 1 (Cdk1) along with up-regulation of the active form of p53, p21 and Bcl-2-associated X (Bax). Furthermore, SN1 and SN2 induced apoptosis by the intrinsic pathway, since they lead to the cleavage of caspase 9, caspase 3 and poly(ADP-ribose) polymerase (PARP), and up-regulating Bax. Phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), nuclear factor-κB (NF-κB) and extracellular signal-regulated kinases (ERK) are important for cell survival and proliferation. SN1 and SN2 lead to decrease in the activity of Akt where the phosphorylated form decreased with time as well as they caused an important decrease in the phosphorylation of ERK and activity of NF-κB. Finally, SN1 and SN2 complexes affected p38/mitogen-activated protein kinase (MAPK) pathway then we recorded an increase in the cyclooxygenase-2 expression and its enzymatic product prostaglandin E2.

Analysis of the in vitro and in vivo effects of photodynamic therapy on prostate cancer by using new photosensitizers, protoporphyrin IX-polyamine derivatives.

BACKGROUND: Photodynamic therapy, using porphyrins as photosensitizers (PS), has been approved in treatment of several solid tumors. However, commonly used PS induce death but also resistance pathways in cancer cells and an alteration of surrounding normal tissues. Because polyamines (PA) are actively accumulated in cancer cells by the Polyamine Transport System (PTS), they may enable PS to specifically target cancer cells. Here, we investigated whether new protoporphyrin IX-polyamine derivatives were effective PS against prostate cancer and whether PA increased PDT specificity after 630nm irradiation. METHODS: CHO and CHO-MG cells (differing in their PTS activity) were used to assess efficacy of polyamine vectorization. MTT assays were performed on human prostate non-malignant (RWPE-1) and malignant (PC-3, DU 145 and LNCaP) cell lines to test PS phototoxicity. ROS generation, DNA fragmentation and cell signalling were assessed by ELISA/EIA, western-blots and gel shift assays. Finally, PS effects were studied on tumor growth in nude mice. RESULTS: Our PS were more effective on cancer cells compared to non-malignant cells and more effective than PpIX alone. PpIX-PA generated ROS production involved in induction of apoptotic intrinsic pathways. Different pathways involved in apoptosis resistance were studied: PS inhibited Bcl-2, Akt, and NF-κB but activated p38/COX-2/PGE2 pathways which were not implicated in apoptosis resistance in our model. In vivo experiments showed PpIX-PA efficacy was greater than results obtained with PpIX. CONCLUSIONS: All together, our results showed that PpIX-PA exerted its maximum effects without activating resistance pathways and appears to be a good candidate for prostate cancer PDT treatment.

Sonic Hedgehog activation is implicated in diosgenin-induced megakaryocytic differentiation of human erythroleukemia cells.

Differentiation therapy is a means to treat cancer and is induced by different agents with low toxicity and more specificity than traditional ones. Diosgenin, a plant steroid, is able to induce megakaryocytic differentiation or apoptosis in human HEL erythroleukemia cells in a dose-dependent manner. However, the exact mechanism by which diosgenin induces megakaryocytic differentiation has not been elucidated. In this study, we studied the involvement of Sonic Hedgehog in megakaryocytic differentiation induced by diosgenin in HEL cells. First, we showed that different elements of the Hedgehog pathway are expressed in our model by qRT-PCR. Then, we focused our interest on key elements in the Sonic Hedgehog pathway: Smoothened receptor, GLI transcription factor and the ligand Sonic Hedgehog. We showed that Smoothened and Sonic Hedgehog were overexpressed in disogenin-treated cells and that GLI transcription factors were activated. Then, we showed that SMO inhibition using siSMO or the GLI antagonist GANT-61, blocked megakaryocytic differentiation induced by diosgenin in HEL cells. Furthermore, we demonstrated that Sonic Hedgehog pathway inhibition led to inhibition of ERK1/2 activation, a major physiological pathway involved in megakaryocytic differentiation. In conclusion, our study reports, for the first time, a crucial role for the Sonic Hedgehog pathway in diosgenin-induced megakaryocytic differentiation in HEL cells.

Cyclooxygenase-2 positively regulates Akt signalling and enhances survival of erythroleukemia cells exposed to anticancer agents.

Cyclooxygenase-2 (COX-2) has been found to be highly expressed in many types of cancers and to contribute to tumorigenesis via the inhibition of apoptosis, increased angiogenesis and invasiveness. In hematological malignancies, COX-2 expression was found to correlate with poor patient prognosis. However, the exact role of COX-2 expression in these malignancies, and particularly in erythroleukemias, remains unclear. The aim of this work was to describe and understand the relationships between COX-2 expression and apoptosis rate in erythroleukemia cells after apoptosis induction by several anticancer agents. We used three different erythroleukemia cell lines in which COX-2 expression was modulated by transfection with either COX-2 siRNA or COX-2 cDNA. These cellular models were then treated with apoptosis inducers and apoptosis onset and intensity was followed. Cell signalling was evaluated in unstimulated transfected cells or after apoptosis induction. We found that COX-2 inhibition rendered erythroleukemia cells more sensitive to apoptosis induction and that in cells overexpressing COX-2 apoptosis induction was reduced. We demonstrated that COX-2 inhibition decreased the pro-survival Akt signalling and activated the negative regulator of Akt signalling, phosphatase and tensin homologue deleted on chromosome 10 (PTEN). Conversely, in COX-2 overexpressing cells, Akt signalling was activated and PTEN was inhibited. In these last cells, inhibition of casein kinase 2 or Akt signalling restored sensitivity to apoptotic agents. Our findings highlighted that COX-2 can positively regulate Akt signalling mostly through PTEN inhibition, partly via casein kinase 2 activation, and enhances survival of erythroleukemia cells exposed to anticancer agents.

Cyclopamine and jervine induce COX-2 overexpression in human erythroleukemia cells but only cyclopamine has a pro-apoptotic effect.

Erythroleukemia is generally associated with a very poor response and survival to current available therapeutic agents. Cyclooxygenase-2 (COX-2) has been described to play a crucial role in the proliferation and differentiation of leukemia cells, this enzyme seems to play an important role in chemoresistance in different cancer types. Previously, we demonstrated that diosgenin, a plant steroid, induced apoptosis in HEL cells with concomitant COX-2 overexpression. In this study, we investigated the antiproliferative and apoptotic effects of cyclopamine and jervine, two steroidal alkaloids with similar structures, on HEL and TF1a human erythroleukemia cell lines and, for the first time, their effect on COX-2 expression. Cyclopamine, but not jervine, inhibited cell proliferation and induced apoptosis in these cells. Both compounds induced COX-2 overexpression which was responsible for apoptosis resistance. In jervine-treated cells, COX-2 overexpression was NF-κB dependent. Inhibition of NF-κB reduced COX-2 overexpression and induced apoptosis. In addition, cyclopamine induced apoptosis and COX-2 overexpression via PKC activation. Inhibition of the PKC pathway reduced both apoptosis and COX-2 overexpression in both cell lines. Furthermore, we demonstrated that the p38/COX-2 pathway was involved in resistance to cyclopamine-induced apoptosis since p38 inhibition reduced COX-2 overexpression and increased apoptosis in both cell lines.

The P2Y2/Src/p38/COX-2 pathway is involved in the resistance to ursolic acid-induced apoptosis in colorectal and prostate cancer cells.

One of the hallmarks of cancer is resistance to apoptosis. Elucidating the mechanisms of how cancer cells evade or delay apoptosis should lead to novel therapeutic strategies. Previously, we showed that HT-29 colorectal cancer cells undergoing apoptosis overexpressed cyclooxygenase-2 (COX-2), in a p38 dependent pathway, to delay ursolic acid-induced apoptosis. Here, we focused on elucidating the upstream signaling pathways regulating this resistance mechanism. The role of ATP as an extracellular signaling molecule took a long time to be accepted. In recent years, ATP and its analogs, via the activation of specific purinergic receptors, have been implicated in many biological processes including cell proliferation, differentiation and apoptosis. In the present report, we have demonstrated a novel role involving purinergic receptors and particularly the P2Y(2) receptor in resistance to ursolic acid-induced apoptosis in both colorectal HT-29 and prostate DU145 cancer cells. We found that ursolic acid induced an increase in intracellular ATP and P2Y(2) transcript levels. Upon activation, P2Y(2) activated Src which in turn phosphorylated p38 leading to COX-2 overexpression which induced resistance to apoptosis in both HT-29 and DU145 cells. Furthermore, Ca(2+)-independent PLA(2) (iPLA(2)) and Ca(2+)-dependent secretory PLA(2) (sPLA(2)) were responsible for arachidonic acid release, the substrate of COX-2. Our findings document that apoptosis triggering was dependent on protein kinase C (PKC) activation in both cell lines after ursolic acid treatment.

HT-29 colorectal cancer cells undergoing apoptosis overexpress COX-2 to delay ursolic acid-induced cell death.

Colorectal cancer is one of the most common cancer types and the third leading cause of cancer-related death in the western world. Generally, colorectal cancers are resistant to anticancer drugs. Several lines of evidence support a critical role for cyclooxygenase-2 (COX-2) during colorectal tumorigenesis and its role in chemoresistance. In this study, we focused our interest on the role played by COX-2 in apoptosis induced in HT-29 human colorectal cancer cells by ursolic acid (UA), a triterpenoid found in a large variety of plants. We showed that UA-induced apoptosis and that COX-2 was overexpressed only in apoptotic cells. We demonstrated that this overexpression was mediated by the p38 MAP kinase pathway as inhibiting its activation using a p38-specific inhibitor, SB 203580, abrogated COX-2 expression. Inhibiting COX-2 expression either by using a p38-specific inhibitor or COX-2-specific siRNA increased apoptosis. These results demonstrated that COX-2 was involved in a resistance mechanism to UA-induced apoptosis in HT-29 cells. Cells undergoing apoptosis were able to trigger a resistance mechanism by overexpressing a protein such as COX-2 to delay their death. Furthermore, we demonstrated that this resistance mechanism was independent of PGE(2) production as the addition of the specific COX-2 activity inhibitor, NS-398, did not affect apoptosis in UA-treated cells.

Effects of the active metabolite of leflunomide, A77 1726, on cytokine release and the MAPK signalling pathway in human rheumatoid arthritis synoviocytes.

Inflammatory cytokines or soluble factors are essential in the pathogenesis of rheumatoid arthritis (RA). Leflunomide is an effective disease modifying antirheumatic drug (DMARD) in RA. The objective of the present study was to evaluate for the first time the effects of A77 1726 on cytokine (interleukin (IL)-8, IL-10, IL-11 secretion and tumor necrosis factor-alpha soluble receptor I (sTNFRI)) shedding in human RA fibroblast-like synoviocytes (FLS). At 100 microM, we observed an increase in IL-10 secretion, a decrease in IL-11 release and no effect on sTNFRI shedding and IL-8 secretion in IL-1beta-stimulated human RA FLS. Furthermore, at this dose, our results also confirmed that A77 1726 decreased IL-6 and prostaglandin E2 (PGE2) synthesis while it increased IL-1 receptor antagonist secretion (IL-1Ra). The mitogen-activated protein kinases (MAPKs) represent an attractive target for RA because they can regulate cytokine expression. At 100 microM, the effect of A77 1726 on IL-10 and IL-11 secretion seemed to be associated with the status of p38 MAPK activation. Our results confirmed the immunoregulatory action of leflunomide in the cytokine network involved in RA pathogenesis. It could shift the balance from cytokine mediated inflammation to cytokine directed inhibition of the inflammatory process.

Diosgenin dose-dependent apoptosis and differentiation induction in human erythroleukemia cell line and sedimentation field-flow fractionation monitoring.

To limit or stop cancer spreading, one of the most prevalent strategies is to induce cancer cell death. Differentiation therapy and apoptosis induction are two ways to achieve this goal. Sedimentation field-flow fractionation (SdFFF) has been described as an effective tool for cell separation, respecting integrity and viability. Because SdFFF takes advantage of intrinsic properties of eluted cells (size, density, shape), we studied the capacity of SdFFF to monitor specific biophysical modifications that occurred during cellular apoptosis or differentiation induction. Then, we used, as an in vitro cellular model of apoptosis and differentiation, diosgenin dose-dependent induction in the polyvalent human erythroleukemia cell line. Two other chemicals were used: phorbol myristate acetate (differentiation inducer) and staurosporine (apoptosis inducer). Our results demonstrated a correlation between SdFFF elution profile changes and induction of effective biological processes. Thus, after acquisition of a reference profile, SdFFF could be used alone to follow chemically induced biological events, suggesting many different applications such as testing series of molecules, evaluation of new cellular/biological models used in different life science fields, or sorting purified populations with the aim of better understanding mechanisms of induced cellular events.