Biomedical subjects

Robert Kiss

Publications and source records attributed to Robert Kiss.

At least 19 recordsLinked to original sources

PubMed2007

Can anti-migratory drugs be screened in vitro? A review of 2D and 3D assays for the quantitative analysis of cell migration.

The aim of the present review is to detail and analyze the pros and cons of in vitro tests available to quantify the anti-migratory effects of anti-cancer drugs for their eventual use in combating the dispersal of tumor cells, a clinical need which currently remains unsatisfied. We therefore briefly sum up why anti-migratory drugs constitute a promising approach in oncology while at the same time emphasizing that migrating cancer cells are resistant to apoptosis. To analyze the pros and cons of the various in vitro tests under review we also briefly sum up the molecular and cellular stages of cancer cell migration, an approach that enables us to argue both that no single in vitro test is sufficient to characterize the anti-migratory potential of a drug and that standardization is needed for the efficient quantitative analysis of cell locomotion in a 3D environment. Before concluding our review we devote the final two parts (i) to the description of new prototypes which, in the near future, could enter the screening process with a view to identifying novel anti-migratory compounds, and (ii) to the anti-migratory compounds currently developed against cancer, with particular emphasis on how these compounds were selected before entering the clinical trial phase.

Animals↗

PubMed2006

Galectin-1: a small protein with major functions.

Galectins are a family of carbohydrate-binding proteins with an affinity for beta-galactosides. Galectin-1 (Gal-1) is differentially expressed by various normal and pathological tissues and appears to be functionally polyvalent, with a wide range of biological activity. The intracellular and extracellular activity of Gal-1 has been described. Evidence points to Gal-1 and its ligands as one of the master regulators of such immune responses as T-cell homeostasis and survival, T-cell immune disorders, inflammation and allergies as well as host-pathogen interactions. Gal-1 expression or overexpression in tumors and/or the tissue surrounding them must be considered as a sign of the malignant tumor progression that is often related to the long-range dissemination of tumoral cells (metastasis), to their dissemination into the surrounding normal tissue, and to tumor immune-escape. Gal-1 in its oxidized form plays a number of important roles in the regeneration of the central nervous system after injury. The targeted overexpression (or delivery) of Gal-1 should be considered as a method of choice for the treatment of some kinds of inflammation-related diseases, neurodegenerative pathologies and muscular dystrophies. In contrast, the targeted inhibition of Gal-1 expression is what should be developed for therapeutic applications against cancer progression. Gal-1 is thus a promising molecular target for the development of new and original therapeutic tools.

Amino Acid Sequence↗

PubMed2006

Galectin 7 (p53-induced gene 1): a new prognostic predictor of recurrence and survival in stage IV hypopharyngeal cancer.

BACKGROUND: Eighty percent of hypopharyngeal squamous cell carcinoma patients have advanced stages (III and IV) of the disease, and biological markers are required to predict high-risk head and neck squamous cell carcinoma patients in need of highly aggressive treatments after surgery to improve the survival rate. We analyzed the potential prognostic value of galectin 7 in a series of 81 stage IV hypopharyngeal SCCs because galectin 7 is an emerging marker involved in the epidermal development of pluristratified epithelia and in epidermal cell migration. METHODS: The immunohistochemical expression of galectin 7 was determined on a series of 81 stage IV hypopharyngeal SCCs and was compared with that of galectins 1 and 3. RESULTS: High levels of galectin 7 expression were associated with rapid recurrence rates and dismal prognoses in these 81 stage IV hypopharyngeal SCCs, a feature not observed with galectin 3 and one observed weakly, if at all, with galectin 1. CONCLUSIONS: These data suggest that the immunohistochemical determination of galectin 7 expression in the case of high-risk hypopharyngeal cancers is a meaningful tool to identify patients who should benefit from aggressive postsurgical adjuvant therapy after surgery, including not only radiotherapy, but also chemotherapy.

Adenocarcinoma↗

PubMed2006

Autophagy, the Trojan horse to combat glioblastomas.

Malignant gliomas, among which glioblastomas constitute the largest group, are characterized by a dramatically diffuse infiltration into the brain parenchyma with, as a consequence, the fact that no patient with glioblastoma multiforme (GBM) has been cured to date. Migrating GBM cells are resistant to apoptosis (Type I programmed cell death), and thus to radiotherapy and conventional chemotherapy, because of the constitutive activation of several intracellular signaling pathways, of which the most important identified to date are the pathways controlled by phosphatidylinositol 3-kinase, Akt, and the mammalian target of rapamycin (mTOR). Migrating GBM cells seem to be less prone to resist autophagy (Type II programmed cell death), and disruption of the pathway controlled by mTOR induces marked autophagic processes in GBM cells. Temozolomide is the most efficacious cytotoxic drug employed today to combat glioblastoma, and this drug exerts its cytotoxic activity through proautophagic processes. Thus, autophagy represents a kind of Trojan horse that can be used to bypass, at least partly, the dramatic resistance of glioblastoma to radiotherapy and proapoptotic-related chemotherapy.

Antineoplastic Agents, Phytogenic↗

PubMed2006

A lactosylated steroid contributes in vivo therapeutic benefits in experimental models of mouse lymphoma and human glioblastoma.

Various mono- and disaccharides were grafted onto a steroid backbone. Whereas in vitro these glycosylated steroids had no cytotoxic effects on six different human cancer cell lines, several of the glycosylated steroids under study did significantly modify the levels of in vitro migration of the human U373 glioblastoma, the A549 non-small-cell-lung cancer (NSCLC), and the PC-3 prostate cancer cells, with more pronounced effects in the case of a monosubstituted beta-L-fucopyranosyl-steroid (19), a monosubstituted beta-D-isomaltosyl-steroid (22), and a monosubstituted beta-D-lactosyl-steroid (24). These three compounds significantly increased the survival of conventional mice grafted subcutaneously with the P388 lymphoma, a lymphoma that metastasizes toward the liver. In vivo, the monosubstituted beta-D-lactosyl-steroid (24) also increased the antitumor effectiveness of cisplatin, a cytotoxic pro-apoptotic drug, in the case of the P388 lymphoma model. This compound also increased the survival of immunodeficient mice into whose brains human U373 glioblastoma cells had been orthotopically grafted.

Animals↗

PubMed2006

Towards functional glycomics by localization of binding sites for tissue lectins: lectin histochemical reactivity for galectins during diethylstilbestrol-induced kidney tumorigenesis in male Syrian hamster.

Endogenous lectins act as effectors of cellular activities such as growth regulation, migration, and adhesion. Following their immunohistochemical localization in our previous study (Saussez et al. in Histochem Cell Biol 123:29-41, 2005) we purified several galectins and used them as tools for monitoring accessible binding sites. Herein, we report the use of galectin histochemistry for the analysis of diethylstilbestrol (DES)-induced renal tumors in male Syrian hamster kidney (SHKT). Sections of normal kidney and DES-treated kidney were analyzed with biotinylated galectins-1, -3 (full-length and truncated), and -7. Accessible binding sites were detected, localization was predominantly extracellular and confined to medium-sized and large tumors. Monitoring the SHKT-derived HKT-1097 line, processed in vitro or as xenograft material, cytoplasmic and nuclear staining for galectins-1, -3, and -3tr could be observed. Adaptation of SHKT cells to long-term growth in culture is thus associated with emergence of this signal. Our data set illustrates the feasibility to complement immunohistochemical data by application of the tissue lectins as probes, and to detect regulation of galectin reactivity with differential characteristics within tumor progression in vivo and unique features of the tumor cell line in vitro and in vivo.

Animals↗

PubMed2006

The synthesis of alternative diketopiperazines as potential RGD mimetics.

Alternative RGD mimetics-with the exception of glycine-c(Arg-Asp) 1, c(Arg-Glu) 2 and c[Arg-Asp(Phe-OH)] 3 were synthesized. The DKPs were prepared on solid phase with orthogonal protection allowing further derivatization in solution. During solution phase cyclization in NH(3)/methanol, the side chain benzyl ester group of H-Arg(Tos)-Asp(OBzl)-OMe and H-Arg(Tos)-Glu(OBzl)-OMe suffer transesterification, while beta-t-butyl or beta-cyclohexyl esters are stable under the same conditions. In spite of the simple structure, all compounds bind selectively to the alpha(v)beta(3) integrin receptor, 3 showing the highest affinity with an IC(50) value of 0.74 microM value. On the other hand only 3 binds with measurable activity to the alpha(IIb)beta(3) receptor (IC(50) 159 microM). The binding affinities seem to be in accordance with the distances between the arginine guanidino and the aspartic acid carboxyl group in extended conformation determined by semiempirical geometry optimization.

Chemistry, Organic↗

PubMed2006

The cardenolide UNBS1450 is able to deactivate nuclear factor kappaB-mediated cytoprotective effects in human non-small cell lung cancer cells.

Non-small cell lung cancers (NSCLC) are associated with very dismal prognoses, and adjuvant chemotherapy, including irinotecan, taxanes, platin, and Vinca alkaloid derivatives, offers patients only slight clinical benefits. Part of the chemoresistance of NSCLCs results from the constitutive or anticancer drug-induced activation of the nuclear factor-kappaB (NF-kappaB) signaling pathways. The present study shows that human A549 NSCLC cells display highly activated cytoprotective NF-kappaB signaling pathways. UNBS1450, which is a cardenolide belonging to the same class of chemicals as ouabain and digitoxin, affected the expression and activation status of different constituents of the NF-kappaB pathways in these A549 tumor cells. The modifications brought about by UNBS1450 led to a decrease in both the DNA-binding capacity of the p65 subunit and the NF-kappaB transcriptional activity. Using the 3-(4,5-dimethylthiazol-2yl)-dephenyltetrazolium bromide colorimetric assay, we observed in vitro that UNBS1450 was as potent as taxol and SN38 (the active metabolite of irinotecan) in reducing the overall growth levels of the human A549 NSCLC cell line, and was more efficient than platin derivatives, including cisplatin, carboplatin, and oxaliplatin. The chronic in vivo i.p. and p.o. UNBS1450 treatments of human A549 orthotopic xenografts metastasizing to the brains and the livers of immunodeficient mice had a number of significant therapeutic effects on this very aggressive model.

Animals↗

PubMed2006

Present and potential future issues in glioblastoma treatment.

The treatment of glioblastomas requires a multidisciplinary approach that takes the presently incurable nature of the disease into consideration. Treatments are multimodal and include surgery, radiotherapy and chemotherapy. Current recommendations are that patients with glioblastomas should undergo maximum surgical resection, followed by concurrent radiation and chemotherapy with the novel alkylating drug temozolomide. This is then to be followed by additional adjuvant temozolomide for a period of up to 6 months. Major advances in surgical and imaging technologies used to treat glioblastoma patients are described. These technologies include magnetic resonance imaging and metabolic data that are helpful in the diagnosis and guiding of surgical resection. However, glioblastomas almost invariably recur near their initial sites. Disease progression usually occurs within 6 months and leads rapidly to death. A number of signaling pathways can be activated constitutively in migrating glioma cells, thus rendering these cells resistant to proapoptotic insults, such as conventional chemotherapies. Therefore, the molecular and cellular therapies and local drug delivery that could be used to complement conventional treatments are described, and some of the currently ongoing clinical trials are reviewed, with respect to these new approaches.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2006

Cardenolide-induced lysosomal membrane permeabilization demonstrates therapeutic benefits in experimental human non-small cell lung cancers.

Non-small cell lung cancers (NSCLCs) are the leading cause of cancer deaths in most developed countries. Targeting heat shock protein 70 (Hsp70) expression and function, together with the induction of lysosomal membrane permeabilization (LMP), could overcome the multiple anti-cell death mechanisms evidenced in NSCLCs that are responsible for the failure of currently used chemotherapeutic drugs. Because cardenolides bind to the sodium pump, they affect multiple signaling pathways and thus have a number of marked effects on tumor cell behavior. The aim of the present study was to characterize in vitro and in vivo the antitumor effects of a new cardenolide (UNBS1450) on experimental human NSCLCs. UNBS1450 is a potent source of in vivo antitumor activity in the case of paclitaxel-and oxaliplatin-resistant subcutaneous human NCI-H727 and orthotopic A549 xenografts in nude mice. In vitro UNBS1450-mediated antitumor activity results from the induction of nonapoptotic cell death. UNBS1450 mediates the decrease of Hsp70 at both mRNA and protein levels, and this is at least partly due to UNBS1450-induced downregulation of NFAT5/TonEBP (a factor responsible for the transcriptional control of Hsp70). These effects were paralleled by the induction of LMP, as evidenced by acridine orange staining and immunofluorescence analysis for cathepsin B accumulation.

Acridine Orange↗

PubMed2006

Anti-galectin compounds as potential anti-cancer drugs.

Galectins form a family of carbohydrate-binding proteins defined by their affinity for beta-galactosides containing glycoconjugates. The carbohydrate recognition domain (CRD) is responsible for the specificity of galectins for saccharides. This binding may result in modulated cell proliferation, cell death and cell migration, three processes that are intimately involved in cancer initiation and progression. Galectins can also display protein-protein types of interactions with their binding partners. Certain galectins directly involved in cancer progression seem to be promising targets for the development of novel therapeutic strategies to combat cancer. Indeed, migrating cancer cells resistant to apoptosis still constitute the principal target for the cytotoxic drugs used to treat cancer patients. Reducing the levels of migration in apoptosis-resistant cancer cells can restore certain levels of sensitivity to apoptosis (and so to pro-apoptotic drugs) in restricted-migration cancer cells. Anti-galectin agents can restrict the levels of migration of several types of cancer cell and should therefore be used in association with cytotoxic drugs to combat metastatic cancer. We provide experimental proof in support of this concept. While the present review focuses on various experimental strategies to impair cancer progression by targeting certain types of galectins, it pays particular attention to glioblastomas, which constitute the ultimate level of malignancy in primary brain tumors. Glioblastomas form the most common type of malignant brain tumor in children and adults, and no glioblastoma patient has been cured to date.

Antineoplastic Agents↗

PubMed2006

Cimetidine, an unexpected anti-tumor agent, and its potential for the treatment of glioblastoma (review).

Cimetidine (CIM), the prototypical histamine H2 receptor antagonist (H2RA), was brought to market based on its ability to accelerate healing of gastrointestinal ulcers through the inhibition of gastric acid secretion. Cimetidine, the most studied H2RA, has been demonstrated to possess anti-tumor activity against colon, gastric and kidney cancers, and melanomas. This activity involves a number of different mechanisms of action: a) CIM antagonizes tumor cell-mediated interleukin-1-induced activation of selectins in liver sinusoids, inhibiting tumor cell binding on liver sinusoids, thereby reducing the development of liver metastasis; b) histamine acts as a growth factor in various tumor cell types via the activation of H2 receptors; CIM therefore may antagonize this effect; c) CIM acts as an immunomodulator by enhancing the host's immune response to tumor cells. With respect to malignant gliomas, CIM added to temozolomide was superior in vivo when compared to temozolomide alone in extending survival of nude mice with human glioblastoma cells orthotopically xenografted into their brain. We review the various mechanisms of action potentially associated with the therapeutic effects of CIM in the case of experimental glioblastomas, observations we hope will encourage clinical investigation of CIM in the management of highly malignant gliomas.

Antineoplastic Agents↗

PubMed2005

Galectin-1 knocking down in human U87 glioblastoma cells alters their gene expression pattern.

We have previously reported that (i) progression of malignancy in patients bearing astrocytic tumors correlates with increased tumor levels of galectin-1; (ii) in vitro addition of purified galectin-1 to U87 human glioblastoma cells enhances tumor cell motility; and (iii) conversely, knocking down galectin-1 expression in this cell line by stable transfection with antisense galectin-1 mRNA impairs motility and delays mortality after their intracranial grafting to nude mice. We here used cDNA microarray analysis to compare the effect on gene expression of stable transfection with antisense galectin-1 vector to mock-transfected and wild-type cells. Among the 631 spots probing genes potentially involved in cancer that were valid for analysis on all the arrays the expression of 86 genes was increased at least 2-fold. Confirmation of increased protein levels was provided by immunocytochemistry for p21waf/cip1, cullin-2, p53, ADAM-15, and MAP-2. Major differences in the expression patterns of ADAM-15 and the actin stress fiber organization were also observed. U87 cells stably deficient for galectin-1 expression were significantly less motile than control. We conclude that the stable inhibition of galectin-1 expression alters the expression of a number of genes that either directly or indirectly influence adhesion, motility and invasion of human glioblastoma cells.

Cell Line, Tumor↗

PubMed2005

Characterization of the activities of actin-affecting drugs on tumor cell migration.

Metastases kill 90% of cancer patients. It is thus a major challenge in cancer therapy to inhibit the spreading of tumor cells from primary tumor sites to those particular organs where metastases are likely to occur. Whereas the actin cytoskeleton is a key component involved in cell migration, agents targeting actin dynamics have been relatively poorly investigated. Consequently, valuable in vitro pharmacological tools are needed to selectively identify this type of agent. In response to the absence of any standardized process, the present work aims to develop a multi-assay strategy for screening actin-affecting drugs with anti-migratory potentials. To validate our approach, we used two cancer cell lines (MCF7 and A549) and three actin-affecting drugs (cytochalasin D, latrunculin A, and jasplakinolide). We quantified the effects of these drugs on the kinetics of actin polymerization in tubes (by means of spectrofluorimetry) and on the dynamics of actin cytoskeletons within whole cells (by means of fluorescence microscopy). Using quantitative videomicroscopy, we investigated the actual effects of the drugs on cell motility. Finally, the combined drug effects on cell motility and cell growth were evaluated by means of a scratch-wound assay. While our results showed concordant drug-induced effects on actin polymerization occurring in vitro in test tubes and within whole cells, the whole cell assay appeared more sensitive than the tube assay. The inhibition of actin polymerization induced by cytochalasin D was paralleled by a decrease in cell motility for both cell types. In the case of jasplakinolide, which induces actin polymerization, while it significantly enhanced the locomotion of the A549 cells, it significantly inhibited that of the MCF-7 ones. All these effects were confirmed by means of the scratch-wound assay except of the jasplakinolide-induced effects on MCF-7 cell motility. These later seemed compensated by an additional effect occurring during wound recolonization (possibly acting on the cell growth features). In conclusion, the use of multi-assays with different levels of sophistication and biological relevance is recommended in the screening of new actin-affecting drugs with potentially anti-migratory effects.

Actins↗

PubMed2005

Performance of a membrane adsorber for trace impurity removal in biotechnology manufacturing.

Membrane adsorbers provide an attractive alternative to traditional bead-based chromatography columns used to remove trace impurities in downstream applications. A linearly scalable novel membrane adsorber family designed for the efficient removal of trace impurities from biotherapeutics, are capable of reproducibly achieving greater than 4 log removal of mammalian viruses, 3 log removal of endotoxin and DNA, and greater than 1 log removal of host cell protein. Single use, disposable membrane adsorbers eliminate the need for costly and time consuming column packing and cleaning validation associated with bead-based chromatography systems, and minimize the required number and volume of buffers. A membrane adsorber step reduces process time, floor space, buffer usage, labor cost, and improves manufacturing flexibility. This "process compression" effect is commonly associated with reducing the number of processing steps. The rigid microporous structure of the membrane layers allows for high process flux operation and uniform bed consistency at all processing scales.

Adsorption↗

PubMed2005

Possible future issues in the treatment of glioblastomas: special emphasis on cell migration and the resistance of migrating glioblastoma cells to apoptosis.

PURPOSE: The present review aims to emphasize that malignant gliomas are characterized by the diffuse invasion of distant brain tissue by a myriad of single migrating cells that exhibit decreased levels of apoptosis (programmed cell death type I), thus a resistance to cytotoxic insult. METHODS: The present review surveys the molecular mechanisms of migration in malignant gliomas and potential issues arising from treatments, in addition to relationships between glioma cell migration and resistance to apoptosis in terms of the molecular signaling pathways. RESULTS: Clinical and experimental data demonstrate that glioma cell migration is a complex combination of multiple molecular processes, including the alteration of tumor cell adhesion to a modified extracellular matrix, the secretion of proteases by the cells, and modifications to the actin cytoskeleton. Intracellular signaling pathways involved in the acquisition of resistance to apoptosis by migrating glioma cells concern PI3K, Akt, mTOR, NF-kappaB, and autophagy (programmed cell death type II). CONCLUSION: A number of signaling pathways can be constitutively activated in migrating glioma cells, thus rendering these cells resistant to cytotoxic insults. However, these pathways are not all constitutively activated at the same time in any one glioma. Particular inhibitors should therefore only be chosen if the target is present in the tumor tissue, but this is only possible if individual patients are submitted to the molecular profiling of their tumors before undergoing any treatment to combat their migratory glioma cells. Specific antimigratory compounds should be added to conventional radio- and/or chemotherapy.

Apoptosis↗

PubMed2005

Identification of a novel cardenolide (2''-oxovoruscharin) from Calotropis procera and the hemisynthesis of novel derivatives displaying potent in vitro antitumor activities and high in vivo tolerance: structure-activity relationship analyses.

Analysis of the methanolic extract of Calotropis procera root barks enabled the identification of a novel cardenolide (2''-oxovoruscharin) to be made. Of the 27 compounds that we hemisynthesized, one (23) exhibited a very interesting profile with respect to its hemisynthetic chemical yield, its in vitro antitumor activity, its in vitro inhibitory influence on the Na+/K+-ATPase activity, and its in vivo tolerance. Compound 23 displayed in vitro antitumor activity on a panel of 57 human cancer cell lines similar to taxol, and higher than SN-38 (the active metabolite of irinotecan), two of the most potent drugs used in hospitals to combat cancer.

Animals↗

PubMed2005

Nuclear galectin-3 expression is an independent predictive factor of recurrence for adenocarcinoma and squamous cell carcinoma of the lung.

The tumor stage is the most powerful prognostic tool for predicting the survival rates of lung carcinoma patients. However, prognosis of individual patients is difficult in part because of the marked clinical heterogeneity among such patients. Galectins are involved in cell growth, apoptosis and cell migration features, and their diagnostic and prognostic values have already been demonstrated in various types of cancers. In the present paper we analyze the potential prognostic value of immunohistochemical galectin-3 expression in lung adenocarcinomas and squamous cell carcinomas. In all, 165 squamous cell carcinomas and 121 adenocarcinomas were immunostained for galectin-3. In each case the immunohistochemical analyses consisted of an evaluation of the percentage of tumor cells stained and the intensity of staining. An IP score (ie Intensity x Percentage) was thus determined for each lung carcinoma. A large majority of cases displayed galectin-3 expression. While the cytoplasmic staining in the squamous cell carcinomas was focal and moderately intense, the staining in the adenocarcinomas was diffuse and intense. The IP scores were significantly (P=0.0001) higher in the adenocarcinomas than in the squamous cell carcinomas. The difference in nuclear expression profiles between the two cancer types was statistically significant (P=0.0005). Cox multivariate analysis carried out on the patients' genders, the TNM classification and the galectin-3-related variables showed that of the galectin-3-related variables, only the nuclear location of galectin-3 was identified as a prognostic indicator of recurrence independent of the clinicopathological features characterizing the patients (P=0.02). The prognostic contribution of this latter variable was enhanced when the patients with relapse-free follow-ups longer than 8 months were considered (P=0.005). Galectin-3 immunohistochemical expression differs between squamous cell carcinomas and adenocarcinomas, but the nuclear expression of galectin-3 behaves as a significant prognostic predictor for all the cases as a group.

Adenocarcinoma↗