N. K. Karamanos

Ultrasensitive capillary electrophoresis of sulfated disaccharides in chondroitin/dermatan sulfates by laser-induced fluorescence after derivatization with 2-aminoacridone.

An ultrasensitive capillary electrophoretic method for separating the variously sulfated chondroitin/dermatan sulfate-derived delta-disaccharides after digestion with chondro/dermatolyases and derivatization with the fluorophore 2-aminoacridone is described. All known mono-, di- and tri-sulfated delta-disaccharides were completely separated using 15 mM orthophosphate buffer (pH 3.0) at 20 kV without any interference of the excess derivatizing reagent. They were detected at the anode (reversed polarity) using either an Ar-ion laser-induced fluorescence (LIF) detector (excitation wavelength 488 nm) or a UV detector. The sensitivity obtained by LIF (0.51 pmol/l) was at least 100 and 10 times higher as compared to those obtained by UV detection at 232 nm of underivatized delta-disaccharides and at 254 nm of those derivatized with aminoacridone, respectively. The method has been easily applied to the analysis of chondroitin/dermatan sulfates from various tissues at the attogram level, including chondrotin/dermatan sulfates from normal and aneurysmal human abdominal aortas.

The Importance of c-Kit and PDGF Receptors as Potential Targets for Molecular Therapy in Breast Cancer

Molecular therapies target key functional molecules in order to halter viable operation of cancer cells. Receptor tyrosine kinases (RTKs) constitute attractive targets, as quite often their abnormal signaling has been associated with tumor development and growth. Overexpression of growth factor receptors, including IGF, EGF, TGF-alpha, SCF and PDGF receptors, has been associated with poor prognosis in breast cancer. Therefore, a number of RTKs are already targets for novel designed drugs, which involve tyrosine kinase inhibitors and monoclonal antibodies. Despite the fact that c-Kit and PDGF-R have been effective targets in a number of cancers, the experimental results in breast have not yet clarified their importance. The expression and function of c-Kit in breast cancer is a quite controversial subject. Several studies propose that the loss of c-Kit expression has been associated with tumor progress, whereas other reports indicate not only its expression but also the implication of c-Kit in breast cancer. On the other hand, the expression of PDGF-R in breast cancer is not in question. A number of inhibitors against tyrosine kinases are currently in trials as to demonstrate their importance in breast cancer treatment. Imatinib (STI571), which is a selective tyrosine kinase inhibitor and particularly of c-Kit and PDGF-R, exhibited encouraging results in respect to its inhibitory effect in cell growth and invasion potential in a panel of human breast cancer cell lines. In this review, the importance of RTKs in human cancer and of c-Kit and PDGF-R as molecular targets in breast cancer treatment, in the view of their expression profiles and the in vitro effects of STI571 is discussed.

Management of malignant pleural effusion by suicide gene therapy in advanced stage lung cancer: a case series and literature review

Gene therapy can be defined as the transfer of genetic material into a cell for therapeutic purposes. Cytosine deaminase (CD) transferred into tumor cells by an adenoviral vector (Ad.CD), can convert the antifungal drug fluorocytosine (5-FC) to the antimetabolite 5-fluorouracil (5-FU), which kills not only the transfected tumor cells but also their neighbors by the so-called ‘bystander effect’. After testing a protocol for Ad.CD transfer and lung tumor burden control in a Lewis mouse model, we used this technique in the management of lung cancer patients with malignant pleural effusion (MPE): two cases are presented investigating the possible enhancement of anticancer effect in both non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC) by local activation of the pro-drug 5-FC. Results were discussed in parallel to a literature review on the topic. 5-FC and Ad.CD were administered intratumorally to Lewis mouse lung carcinoma and the effect was monitored by tumor size and electromicroscopy. Two patients with advanced stage lung cancer (1SCLC, 1NSCLC), which developed MPE during first-line treatment were administered 1012 plaque-forming unit (pfu) Ad.CD by intrapleural instillation, in two doses (day1 and day7). Instillation was performed when the pleural fluid was ⩽200 ml. In addition, they received 5-FC 500 mg four times daily for 14 days. Lung tumor regression and successful transfer of adenoviral particles were observed in treated animals. Patients presented complete regression of pleural effusion as monitored by computerized tomography scan. Neutrapenia and anemia were the most severe adverse effect presented (grade III/grade IV 100%). The increased toxicity followed by the intrapleural gene therapy indicates the augmentation of anticancer effect of transformed pro-drug 5-FC to active 5-FU. The obtained data indicate that intrapleural gene therapy may be a useful tool, adjunct to chemotherapy, in the management of MPE related to lung cancer.

Effects of glycosaminoglycans on proliferation of epithelial and fibroblast human malignant mesothelioma cells: a structure–function relationship

Abstract. Proteoglycans interact with other effective macromolecules regulating a variety of cellular events via their glycosaminoglycan (GAG) chains. The effects of all known glycosaminoglycans (GAGs) produced by normal cells and tissues on the proliferation of two human malignant mesothelioma cell lines, one with fibroblast‐like morphology and the other with epithelial differentiation – both able to produce hyaluronan (HA), galactosaminoglycans (GalAGs) and heparan sulphate (HS) containing proteoglycans – have been studied. Cell proliferation was assessed by measuring [3H]thymidine incorporation and cell number. GalAGs, i.e. chondroitin sulphates (CSs) and dermatan sulphate (DS), strongly stimulate the proliferation of fibroblast‐like cells in a dose‐dependent manner (170–250% at 100 μg/ml), independently of their sulphation pattern. In epithelial cells, however, only DS stimulates cell proliferation. The effects of CSs on proliferation of epithelial cells are not depended on their sulphation pattern. Thus, CSs either with ‐[GlcA‐GalNAc‐(‐6‐O‐SO3−)]‐ or ‐[GlcA‐GalNAc‐(‐4‐O‐SO3−]‐ as the commonest unit, had no significant effect. l‐Iduronic acid (IdoA)‐rich heparin and fast‐moving HS (fm‐HS), a HS fraction with a heparin‐like structure, had significant antiproliferative effects on mesothelioma cells of both types (30–70% at 1.0 μg/ml and 85–90% at 100 μg/ml, respectively). GlcA‐rich HS, however, had no significant effects. HA inhibits only the proliferation of fibroblast‐like cells by 25% at 50 and 100 μg/ml. Keratan sulphate suppresses cell proliferation (10–30%) in both cell lines. In the view of these findings, a structure–function relationship of GAGs on cell proliferation of the two human malignant mesothelioma cell lines is discussed. Other factors, such as chain conformation and geometry, as well as interactions of growth factors with GAGs, possibly involved in the regulation of cell proliferation, are also discussed.

Determination and biological relevance of serum cross-linked type I collagen N-telopeptide and bone-specific alkaline phosphatase in breast metastatic cancer.

Bone metastasis is a frequent complication of cancer disease. The metastatic spread of cancer to bone is common to many different malignancies, particularly breast (ca. 73%), prostate (ca. 68%) and lung (ca. 36%) cancers. Metastases to bone cause increased bone resorption both from direct effects of the tumor itself and thought osteoclastic activation. The diagnosis and follow-up of bone metastatic cancer patients usually relies on skeletal X-ray and bone scintigraphy. However, the development of biochemical markers, used as indicators of bone metabolism, provides data useful in the clinical practice. The most important markers for bone remodeling process, bone formation and resorption, are bone-specific alkaline phosphatase (BAP) and N-telopeptide of type I collagen (NTx), respectively. In this report, we applied two solid-phase immunoassays used for the determination of BAP and NTx in serum of breast cancer (BC) post-menopausal women with bone metastasis and healthy individuals. BAP level in patients was found to be 45.72 +/- 12.92 U/l, while the normal range for healthy individuals was 14.2 - 42.7 U/l. The respective level of serum NTx was 19.20 +/- 8.87 nM bone collagen equivalents (BCE) for patients and 15.9 +/- 3.8 nM BCE for healthy women. Correlation of the obtained data showed elevated levels for both markers indicating high rate of bone degradation in breast metastatic cancer.

Development of an hplc method for determining the alpha2-adrenergic receptor agonist brimonidine in blood serum and aqueous humor of the eye

A procedure for determining brimonidine [5-bromo-6-(2-imidazolidinylideneamino) quinoxaline] in biological samples using a reversed-phase isocratic HPLC method is described. The application in blood serum and eye aqueous humor of patients treated with the Alphagan ophthalmic solution was carried out by enrichment of samples in brimonidine with solid-phase liquid extraction. Brimonidine reached maximum levels in aqueous humor and serum within 2-2.5 h, whereafter a declining pattern was obtained. An approximate 50% level of brimonidine was identified in serum at 12 h after ocular administration, whereas in aqueous humor this percentage was determined after a period of 4-5 h.

Clara cell secretory protein: determination of serum levels by an enzyme immunoassay and its importance as an indicator of bronchial asthma in children

Clara cell secretory protein (CC16) is a 16kDa protein secreted by Clara cells in the lining fluid of bronchiolar and bronchial epithelium. CC16 presents several biologic properties, and has been shown to have immunomodulatory and anti-inflammatory activity. It may play a role in controlling inflammation in the airway. There is some evidence that the CC16 level is primarily lower in adult individuals with bronchial asthma, thus contributing to its pathophysiology. This study was designed to examine CC16 serum levels of children, healthy and with asthma. An enzyme solid phase immunoassay utilizing monoclonal antibody to CC16 was the analytical method to determine the protein concentration in blood sera. The method showed excellent linearity, high sensitivity (detection limit: <50 ng/l) and precision. It was found that asthmatic children appear significantly lower levels (P < 0.001) of CC16 in serum as compared to healthy ones. It is, therefore, concluded that CC16 may be a useful diagnostic index of bronchial asthma in the early child-age.

An enzyme immunoassay to determine the levels of specific antibodies toward bacterial surface antigens in human immunoglobulin preparations and blood serum.

Human polyvalent intravenous immunoglobulin (IVIG) preparations are used as a complementary aid to the proper antimicrobial treatment of severely septic patients in intensive care units (ICUs) and/or as a prophylactic agent to immunocompromised hosts, particularly prone to bacterial infections. There is skepticism about the usefulness of IVIGs since it is not known whether their administration ensures the enhancement of humoral immune responses by providing a sufficient amount of specific antibodies towards the specified bacterial pathogen to be treated. In this report, a simple and reproducible enzyme-linked immunosorbent assay for determining the content of specific antibodies against bacterial surface antigens in commercially available IVIG preparations is described. The method is also easily applied to determine the amount of bacterial antibodies in blood serum. The levels of specific antibodies toward gram positive and negative pathogenic isolates often encountered in ICUs were estimated in two IVIG (Sandoglobulin and Gamimmune) preparations. Significant differences regarding the content of antibodies to certain clinically bacterial isolates were identified not only between the two IVIG preparations tested, but also among various lots from each IVIG preparation. No significant variation (P < or = 0.001) among the bottles derived from the same lot was determined in both preparations. The variation in the levels of specific antibodies in IVIG preparations may be attributed to differences between the donor pools as well as the manufacturing procedure. Application of the method to patients with primary immune deficiencies showed that infusion of highly reactive IVIG preparations enhanced significantly their humoral response toward various pathogens. The results of this study suggest that the content determination of pathogen-specific antibodies in IVIG preparations before administration may be of great importance for treating bacterial infections.

Expression of matrix macromolecules and functional properties of EGF-responsive colon cancer cells are inhibited by panitumumab

SummaryThe epidermal growth factor receptor (EGFR) is a member of the HER family receptors and its activation induced by its natural ligand EGF results in colon cancer growth and progression. Panitumumab (pmAb) is a fully human IgG2 anti-EGFR antibody that blocks the EGFR actions. In the present study, we evaluated the effects of pmAb on the EGF-mediated cellular responses in a panel of colon cancer cells (HCT-8, HT-29, DLD-1 and HCT-116). HCT-1116 and DLD-1 cells showed no significant EGF-dependent cell proliferation; HT-29 and HCT-8 exhibited an EGF-dependent proliferation, with HCT-8 cells to be the most responsive with significant EGFR phosphorylation upon treatment with EGF. The effects of pmAb were then evaluated in the most EGF-responsive cells, HCT-8. In that respect, pmAb impedes the signaling cascade mediated by EGFR intracellular phosphorylation and activity of focal adhesion kinase (FAK) as well as the EGF-induced invasive and migratory potential of colon cancer cells. At the level of matrix effectors implicated in colon cancer progression we report that pmAb is a potent inhibitor of constitute and EGF-mediated gene expression of certain matrix effectors, such as membrane-type 1 metalloproteinase (MT1-MMP), extracellular metalloproteinases inducer (EMMPRIN), urokinase plasminogen activator (uPA) and syndecan-4. The obtained data demonstrated that pmAb is a specific blocker of EGF-mediated EGFR activation, resulting in a significant inhibition of colon cancer cell proliferation in early stages of growth, migration and invasiveness as well as of matrix effector implicated in cancer progression.

Capillary electrophoretic analysis of brimonidine in aqueous humor of the eye and blood sera and relation of its levels with intraocular pressure.

The aim of this study was the development of a capillary electrophoretic method for the determination of the levels of the selective alpha(2)-adrenergic receptor agonist brimonidine in aqueous humor of the eye and blood sera and their relation to its efficacy in reducing the intraocular pressure (IOP). Analysis of brimonidine was performed by capillary zone electrophoresis using 20 mM borate, pH 9.3, as operating buffer and detection at 255 nm. Brimonidine levels were determined in aqueous humor and blood sera from seven patients admitted for cataract extraction following ocular administration of the ophthalmic Alphagantrade mark solution. Levels of brimonidine and IOP values were recorded for a 24 h period. Alphagantrade mark administration resulted in a significant reduction of IOP, from within 30 min up to 4-5 h, whereafter a stepwise increase was recorded until 24 h, where mean IOP value returned to that before administration. The IOP reduction was related to the levels of brimonidine in aqueous humor, where maximal levels (80-100%) were obtained within 1-3 h. A 50% amount of the solution was determined after 4-5 h, whereas it reached the minimum level after 12 h. Serum levels reached maximum within 3-4 h, a 50% reduction was recorded in 12 h and minimum level in 24 h. It is concluded that brimonidine administration may significantly reduce IOP in patients when its level is maintained >/=50% of the maximum present in aqueous humor, i.e within a 4-6 h period. Since at this time the level of brimonidine in blood serum has reached maximum value, administration of brimonidine every 6 h may be used to obtain adequate brimonidine levels to maintain a constantly lowered IOP.