Synthesis and examination of 1,2,4-triazine-sulfonamide hybrids as potential inhibitory drugs: Inhibition effects on AChE and GST enzymes in silico and in vitro conditions.

The crucial functions of acetylcholinesterase (AChE) in neurotransmission and glutathione S-transferase (GST) in detoxification and cellular protection underscore their pivotal roles as key enzymes, essential for maintaining the integrity of neurological and cellular homeostasis. For this purpose, a series of 1,2,4-triazine-sulfonamide hybrids (3a-r) was successfully synthesized, and subsequently evaluated for their inhibitory effects on AChE and GST. The investigation was complemented by molecular docking studies and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) predictions. The synthesized hybrids demonstrated significant promise in inhibiting both AChE and GST activities. Molecular docking analyses provided insights into the interactions between the compounds and the target enzymes, shedding light on potential binding modes and key amino acid residues involved. Furthermore, the study benefited from ADMET predictions, offering valuable information on the compounds' pharmacokinetic properties and potential toxicity. The promising results obtained from this comprehensive approach highlight the potential of these 1,2,4-triazine-sulfonamide hybrids as effective inhibitors of AChE and GST, paving the way for further development and optimization in the pursuit of novel therapeutic agents.

Synthesis, structure and sulfonamide-sulfonimide tautomerism of sulfonamide-1,2,4-triazine derivatives.

Two new 1,2,4-triazine-containing sulfonamide derivatives, namely, 4-bromo-N-(5,6-diphenyl-2H-1,2,4-triazin-3-ylidene)benzenesulfonamide, C21H15BrN4O4S, 3a, and methyl 2-{[(5,6-diphenyl-1,2,4-triazin-3-yl)sulfamoyl]methyl}benzoate, C24H20N4O4S, 3b, which crystallize in the different sulfonimide and sulfonamide tautomeric forms, respectively, were synthesized and characterized by spectroscopic, X-ray diffraction and theoretical calculation methods. Both molecules adopt a very similar conformation of the common part of the structure and the differences occur within the substituents on the sulfonamide group. The amino groups characteristic for the existing tautomeric forms are involved in strong intermolecular N-H...N and N-H...O hydrogen bonds in 3a and 3b, respectively. The Hirshfeld surface analysis showed that H...H contacts constitute a high percentage of the intermolecular interactions. Theoretical calculations at the ab initio DFT/B3LYP/6-311++G(d,p) level showed that the two tautomeric forms observed for 3a and 3b can co-exist in chloroform, ethanol and water solutions, with a distinct predominance of the sulfonamide form; the participation of the sulfonimide form increases with increasing solvent polarity.

Synthesis and structures of three new pyridine-containing oxazoline ligands of complexes for asymmetric catalysis.

Three new chiral pyridine-containing oxazoline derivatives with fluorine and perfluoromethyl groups, namely, 2-({2-[(4S)-4-phenyl-4,5-dihydro-1,3-oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C21H16F3N3O, 2-({5-fluoro-2-[(4S)-4-isopropyl-4,5-dihydro-1,3-oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C18H17F4N3O, and 2-({2-[(3aR,8aS)-8,8a-dihydro-3aH-indeno[1,2-d]oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C22H16F3N3O, as chiral ligands in metal-catalysed asymmetric reactions, were synthesized and characterized by spectral and X-ray diffraction methods. The conformation of the molecules is influenced by strong N-H...N hydrogen bonding and weak C-H...X (X = O and N) interactions. There are no intermolecular hydrogen bonds in the crystal structures of the analysed compounds. Hirshfeld surface analysis showed that the H...H contacts constitute a high percentage of the intermolecular interactions. The conformational analysis was performed by theoretical calculations using the density functional theory (DFT) method. The mechanism of complex formation in terms of the electron-withdrawing effect of the substituents on the oxazoline ring and the ligand conformation is discussed.

Epigenetic Changes Affecting the Development of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) remains a serious oncologic issue with still a dismal prognosis. So far, no key molecular mechanism that underlies its pathogenesis has been identified. Recently, by specific molecular approaches, many genetic and epigenetic changes arising during HCC pathogenesis were detected. Epigenetic studies revealed modified methylation patterns in HCC tumors, dysfunction of enzymes engaged in the DNA methylation process, and a set of histone modifications that influence gene expression. HCC cells are also influenced by the disrupted function of non-coding RNAs, such as micro RNAs and long non-coding RNAs. Moreover, a role of liver cancer stem cells in HCC development is becoming evident. The reversibility of epigenetic changes offers the possibility of influencing them and regulating their undesirable effects. All these data can be used not only to identify new therapeutic targets but also to predict treatment response. This review focuses on epigenetic changes in hepatocellular carcinoma and their possible implications in HCC therapy.

Epigenetic Changes in Gestational Diabetes Mellitus.

Gestational diabetes mellitus (GDM) is defined as carbohydrate intolerance that appears or is for the first time diagnosed during pregnancy. It can lead to many complications in the mother and in the offspring, so diagnostics and management of GDM are important to avoid adverse pregnancy outcomes. Epigenetic studies revealed the different methylation status of genes in pregnancies with GDM compared to pregnancies without GDM. A growing body of evidence shows that the GDM can affect not only the course of the pregnancy, but also the development of the offspring, thus contributing to long-term effects and adverse health outcomes of the progeny. Epigenetic changes occur through histone modification, DNA methylation, and disrupted function of non-coding ribonucleic acid (ncRNA) including microRNAs (miRNAs). In this review, we focus on the recent knowledge about epigenetic changes in GDM. The analysis of this topic may help us to understand pathophysiological mechanisms in GDM and find a solution to prevent their consequences.

An association of iNKT+/CD3+/CD161+ lymphocytes in ovarian cancer tissue with CA125 serum concentration.

The purpose of this study was to investigate the association of iNKT (human invariant natural killer T) cells with the key marker of ovarian cancer (OC) - CA125 (cancer antigen125) in serum. The study reports the assessment of iNKT cells in peripheral blood and tissue of benign and borderline ovarian tumors (BOTs) and in the advanced-stage ovarian cancer. The study groups were as follows: 25 women with benign ovarian tumors, 11 women with BOTs, and 24 women with primary advanced-stage ovarian cancers. The control group consisted of 20 patients without the ovarian pathology. The rates of iNKT lymphocytes in the peripheral blood and tissue specimens were evaluated by a flow cytometry. Significant differences in the percentage of iNKT+/CD3+ of CD3+ lymphocytes, iNKT+/CD3+/CD161+ among CD3+ and iNKT+/CD3+/CD161+ among CD3+/iNKT+ between the control group and patients with ovarian tumors in the peripheral blood and tumor tissue were identified. Significant correlations were noticed between the proportion of lymphocytes iNKT+/CD3+/CD161+ among CD3+/iNKT cells in blood and in cancer tissue of both benign and malignant tumors. In the OC group, neither the ratio of iNKT cells in the blood (P = 0.07), nor the intra-tumor NKT-cell infiltration (P = 0.5) were independent prognostic factors for the follow-up. An increased rate of iNKT cells was detected in benign ovarian tumors compared to OCs. In patients with ovarian cancer, a higher rate of iNKT cells in tumor tissue was present related to that noted in the patient's blood. In addition, a correlation was discovered between the CA125 serum marker and NKT cells from the ovarian cancer tissue. This article has for the first time demonstrated a negative relationship between serum levels and NKT lymphocyte count from ovarian tissue. The inflammatory process in ovarian cancer tissue and the potential infiltration of endothelial immune cells, may result in a reduced number of NKT cells in the tumor microenvironment and increased circulation of the CA125 marker. Presented findings underscore new aspects of the iNKT cells involvement in the ovarian cancer development.

An association of circulating Tregs and Th17 cells producing IL-21 and IL-22 with the ROMA in ovarian cancer patients.

The purpose of the present study was to assess the association of regulatory T cells (Tregs; CD4+ FOXP3+) and helper T lymphocytes (Th17) releasing interleukin (IL)-21 and IL-22, with the Risk of Ovarian Malignancy Algorithm (ROMA). Similar association was made with two additional tumour markers, human epididymis protein 4 (HE4) and carbohydrate antigen 125 (CA125) from patients serum. The presence of Tregs and Th17 was determined both in the peripheral blood and in the tissue of epithelial ovarian tumors. Mononuclear cells obtained from patient's peripheral blood (PBMCs) and from ovarian tissue were isolated by density gradient centrifugation. As a control group patients who had undergone surgery for infertility without ovarian pathology were selected. The percentage of Tregs and Th17 releasing IL-21 or IL-22 cells from both peripheral blood and tumor tissue was measured by flow cytometry. No differences in demographic parameters like body mass index, age, or gravidity were observed among the studied groups. However, an increased concentration of marker HE4 and value of ROMA was identified in individuals with ovarian cancer when compared with women with cystadenomas. Furthermore, a negative correlation between the ROMA value in the serum and Tregs from the peripheral blood of patients with cystadenoma ovarian tumors was detected. The presented work documents, for the first time, the negative association between peripheral blood Tregs and ROMA evaluation based on the tumour markers present in the serum of women with ovarian cystadenoma. Such an effect might result from the negative impact of Tregs on the inflammation process and on tumorigenesis caused by the persistent inflammation.

1,2,4-Triazine Sulfonamides: Synthesis by Sulfenamide Intermediates, In Vitro Anticancer Screening, Structural Characterization, and Molecular Docking Study.

In this study, we synthesized novel sulfonamides with a 1,2,4-triazine moiety according to pharmacophore requirements for biological activity. All the synthesized compounds were tested in vitro to verify whether they exhibited anticancer activity against the human breast cancer cell lines MCF-7 and MDA-MB-231. Among them, two most active ones, having IC50 values of 50 and 42 µM, respectively, were found to show higher anticancer activity than chlorambucil used as the reference in the in vitro tests. In addition, two other compounds, which had IC50 values of 78 and 91 µM, respectively, exhibited a similar level of activity as chlorambucil. X-ray analysis carried out for two of the compounds confirmed their synthesis pathway as well as their assumed molecular structures. Furthermore, a conformational analysis was performed, and electronic parameters of molecules were characterized using theoretical calculations at AM1 and DFT level. Moreover, molecular docking revealed the mode of binding of the investigated 1,2,4-triazine sulfonamides with the human estrogen receptor alpha (ERα).

Halogenated aromatic thiosemicarbazones as potent inhibitors of tyrosinase and melanogenesis.

A set of 21 halogenated thiosemicarbazones (TSCs) have been synthesized and its inhibitory properties toward activity diphenolase of mushroom tyrosinase and their ability to inhibition of melanogenesis in B16F10 murine, melanoma cell line have been investigated. The molecular docking to the active site of the enzyme has been also performed to investigate the nature of enzyme-inhibitor interactions. The obtained outcomes allowed us to perform SAR analysis. TSC 6, 12 and 21 exhibited the most potent inhibitory properties showing IC50 of 0.5, 0.9 and 0.8 µM, respectively. They revealed reversible and competitive manner of tyrosinase inhibition. According to SAR analysis, para-substituted acetophenone derivatives of thiosemicarbazones have the highest affinity to the enzyme among the investigated compounds. Melanin production in B16F10 cells was inhibited by all investigated compounds at the micromolar level. Suggested inhibition mechanism is based on the interaction between a sulfur atom of thiourea moiety of the thiosemicarbazones, and copper ions in the active site of the enzyme. These results might be useful in searching novel inhibitors of melanogenesis which could be used in the cosmetic and food industry.

Small extracellular vesicles containing arginase-1 suppress T-cell responses and promote tumor growth in ovarian carcinoma.

Tumor-driven immune suppression is a major barrier to successful immunotherapy in ovarian carcinomas (OvCa). Among various mechanisms responsible for immune suppression, arginase-1 (ARG1)-carrying small extracellular vesicles (EVs) emerge as important contributors to tumor growth and tumor escape from the host immune system. Here, we report that small EVs found in the ascites and plasma of OvCa patients contain ARG1. EVs suppress proliferation of CD4+ and CD8+ T-cells in vitro and in vivo in OvCa mouse models. In mice, ARG1-containing EVs are transported to draining lymph nodes, taken up by dendritic cells and inhibit antigen-specific T-cell proliferation. Increased expression of ARG1 in mouse OvCa cells is associated with accelerated tumor progression that can be blocked by an arginase inhibitor. Altogether, our studies show that tumor cells use EVs as vehicles to carry over long distances and deliver to immune cells a metabolic checkpoint molecule - ARG1, mitigating anti-tumor immune responses.

Phosphonic and Phosphinic Acid Derivatives as Novel Tyrosinase Inhibitors: Kinetic Studies and Molecular Docking.

A dozen of phosphonic and phosphinic acid derivatives containing pyridine moiety were synthesized and its inhibitory activity toward mushroom tyrosinase was investigated. Moreover, molecular docking of these compounds to the active site of the enzyme was performed. All the compounds (1-10) demonstrated the inhibitory effect with the IC50 and inhibition constants ranging millimolar concentrations. The obtained results indicate that the compounds show different types of inhibition (competitive, noncompetitive, mixed), but all of them are reversible inhibitors. The obtained outcomes allowed to make the structure-activity relationship (SAR) analysis. Compound 4 ([(benzylamino)(pyridin-2-yl)methyl]phenylphosphinic acid) revealed the lowest IC50 value of 0.3 mm and inhibitory constant of Ki 0.076 mm, with noncompetitive type and reversible mechanism of inhibition. According to SAR analysis, introducing bulky phenyl moieties to phosphonic and amino groups plays an important role in the inhibitory potency on activity of mushroom tyrosinase and could be useful in design and development of a new class of potent organophosphorus inhibitors of tyrosinase. Combined results of molecular docking and SAR analysis can be helpful in designing novel tyrosinase inhibitors of desired properties. They may have broad application in food industry and cosmetology.

Deleted in Liver Cancer 2 (DLC2) protein expression in hepatocellular carcinoma.

Deleted in Liver Cancer (DLC) proteins belong to the family of RhoGAPs and are believed to operate as negative regulators of the Rho family of small GTPases. So far, the role of the first identified member from the DLC family, DLC1, was established as a tumor suppressor in hepatocellular carcinoma. The function of its close family relative, DLC2 is unequivocal. In the present study we attempted to determine whether the loss of DLC2 is a common feature of hepatocellular carcinoma tissue. We examined two types of hepatocellular carcinoma- typical and fibrolamellar one. Our analysis revealed that DLC2 protein is not diminished in cancer tissue when compared to non-cancerous liver specimens. What is more, we observed DLC2 to be more abundantly expressed in cancer tissue, particularly in tumors with the inflammation background. In addition, we found that DLC2 gene status was diploid in virtually all tumor samples examined. Our results indicate that DLC2 is not diminished in hepatocellular carcinoma cells. It appears that members of the DLC family, although structurally highly related, may function differently in cancer cells.

Synthesis of unsymmetrical disulfanes bearing 1,2,4-triazine scaffold and their in vitro screening towards anti-breast cancer activity.

ABSTRACT: A new series of 1,2,4-triazine unsymmetrical disulfanes were prepared and evaluated as anticancer activity compounds against MCF-7 human breast cancer cells with some of them acting as low micromolar inhibitors. Evaluation of the cytotoxicity using an MTT assay, the inhibition of [3H]-thymidine incorporation into DNA demonstrated that these products exhibit cytotoxic effects on breast cancer cells in vitro. The most effective compounds with 59 and 60 µM compared to chlorambucil with 47 µM were disulfanes bearing methyl and methoxy substituent in an aromatic ring. Furthermore, all new 14 compounds were obtained with 22-74% yield via mild and efficient synthesis of the sulfur-sulfur bond formation from thiols and symmetrical disulfanes using 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). The molecular structure of the newly obtained compounds was confirmed by X-ray analysis. The conformational preferences of disulfide system were characterized using theoretical calculations at DFT level and statistical distributions of C-S-S-C torsion angle values based on the Cambridge Structural Database (CSD). The DFT calculations and CSD searching show two preferential conformations for C-S-S-C torsion angle close to ± 90° and relatively large freedom of rotation on S-S bond in physiological conditions. The molecular docking studies were performed using the human estrogen receptor alpha (ERα) as molecular target to find possible binding orientation and intermolecular interactions of investigated disulfanes within the active site of ERα. The S…H-S and S…H-C hydrogen bonds between sulfur atoms of bisulfide bridge and S-H and C-H groups of Cys530 and Ala350 as protein residues play crucial role in interaction with estrogen receptor for the most anticancer active disulfane.

Adrenal cyst with both Müllerian and mesothelial differentiation- a clinicopathological and immunohistochemical study with implications for histogenesis.

True epithelial-lined cysts are rare forms of adrenal cystic lesions, the pathogenesis of which is still not fully understood. In this report we present a case of an adrenal cyst diagnosed incidentally on imaging in a 31-year-old, previously healthy, obese woman. Due to non-specific hormonal disorders and enlargement of the lesion, a right-sided laparoscopic adrenalectomy was performed. The cyst was lined predominantly by ciliated cuboidal-to-columnar, Müllerian-type epithelium, and focally by flat-to-cuboidal, mesothelium-like lining. Immunohistochemistry demonstrated a strong positive reaction in the cells of both types of lining for CKAE1+E3, CK19, CK7 and WT1, and both had a negative reaction for CK20, CD34, Melan-A, SF1, TTF1, SMA and CDX2. The cells of the ciliated cuboidal-to-columnar epithelium were strongly positive for PAX8, ER, Ep-CAM and EMA, focally positive for PR, and were negative for calretinin, whereas the cells of the flat-to-cuboidal lining were positive for calretinin and podoplanin and showed only a weak positive response in individual cells for PAX8, EMA and Ep-CAM, but were negative for ER and PR. This is the first reported case of an adrenal ciliated epithelial cyst with Müllerian differentiation (confirmed immunohistochemically) in the English literature. The differences in morphology and immunophenotype of the two types of lining (epithelial Müllerian phenotype versus mesothelial phenotype), suggest that some adrenal epithelial cysts probably form due to metaplasia of mesothelium-derived lining. A similar mechanism may also be involved in the pathogenesis of at least some of the so-called Müllerian cysts (or inclusions) in other locations.

Immunohistochemical differentiation between muscularis mucosae and muscularis propria for improving the staging of bladder cancer in patients undergoing transurethral resection of bladder tumours.

Microscopic differentiation between muscularis mucosae (MM) and muscularis propria (MP) of the bladder in the material obtained during transurethral resection (TUR) remains difficult. The study was aimed at determination of the usefulness of immunohistochemical staining in this context. Forty-seven TUR specimens were stained with 5 mouse anti-human antibodies: anti-desmin, anti-filamin, anti-type IV collagen, anti-smoothelin, and anti-vimentin. Slides were assessed under light microscopy and the intensity of the immune reaction within MM and MP was evaluated on a four-level visual scale as follows: negative (0) and weakly (1), moderately (2), or strongly (3) positive. MM was identified in 27 patients (57.4%). The modal values of reaction intensity in MM and MP was 0 and 2 for desmin (p > 0.05), 2 and 2 for filamin (p = 0.01), 2 and 2 for type IV collagen (p > 0.05), 1 and 2 for smoothelin (p = 0.03), and 2 and 0 for vimentin (p = 0.02), respectively. Identical intensity within MM and MP was observed in 7.1%, 28.6%, 20%, 30.1%, 5.6%, respectively. Immunohistochemistry can help differentiate between MM and MP in TUR specimens. As of yet, no single marker can reliably differentiate between MM and MP; however, a combination of anti-filamin, anti-smoothelin, and anti-vimentin antibodies may be reasonable for diagnostic purposes.

Angiogenesis in CD5-positive Diffuse Large B Cell Lymphoma: A Morphometric Analysis.

BACKGROUND: CD5-positive diffuse large B cell lymphoma (DLBCL) is the least frequent immunohistochemical subgroup of DLBCL. The relatively little available data suggests a worse outcome in this population, resulting from a resistance to chemotherapy. OBJECTIVES: The aim was the comparative assessment of angiogenesis in both CD5-positive and CD5-negative DLBCL, as well as in lymphatic tissues without lymphoproliferative diseases. MATERIAL AND METHODS: The analysis included 36 cases of CD5-positive DLBCL (19 females and 17 males) aged 29-87 years (mean age 69), diagnosed and treated in the Maria Sklodowska-Curie Institute and Oncology Center and Medical University of Warsaw in 2002-2013. The control group comprised 28 cases of CD5-negative DLBCL (14 females and 14 males) aged 24-82 years (mean age 58.5). The secondary control group (13 cases) consisted of normal lymphatic tissue obtained from patients without lymphoproliferative diseases. The level of angiogenesis was assessed on the basis of immunohistochemical CD34, vWF and HIF1α expression measured using morphometric methods. RESULTS: CD5-positive DLBCL, in comparison to CD5-negative DLBCL, was characterized by: (1) higher mean of total blood vessel area, (2) higher mean total ratio of blood vessel area and staining intensity, (3) higher mean of total blood vessel area in regions defined as hot spots, (4) higher mean of total ratio of blood vessel area and staining intensity in hot spots. The measurements in lymph nodes without lymphoproliferative diseases lay between the values obtained in both DLBCL subgroups. CONCLUSIONS: We observed a significant exacerbation of angiogenesis in CD5-positive DLBCL in comparison to the CD5-negative subgroup, possibly explaining its more aggressive clinical course. Our data does not substantiate the hypothesis that angiogenesis is more pronounced in frequent CD5-negative DLBCL subgroup in comparison to benign lymphatic tissue.

Effect of IL-6 and IL-8 on the expression of the complement activation inhibitors MAC-inhibitory protein and decay-accelerating factor in ovarian cancer A2780 cells.

The aim of the present study was to evaluate the role of interleukin (IL)-6 and IL-8 on the expression of the membrane-bound complement inhibitors membrane attack complex-inhibitory protein (CD59) and decay-accelerating factor (CD55), in the human ovarian carcinoma A2780 cell line, which is a non-producing IL-6 cell line that does exhibit IL-6 responsiveness, due to the presence of IL-6 receptors. Extracellular levels of complement system inhibitors were evaluated by western blotting and reverse transcription-quantitative polymerase chain reaction. Cellular localization of CD55 and CD59 in the ovarian cancer cells was assessed by immunofluorescence. The detection of a soluble form of CD55 and CD59 released by the A2780 cells following stimulation with IL-6 and IL-8 was detected by enzyme-linked immunosorbent assay. The present data revealed that A2780 cells express CD55 and CD59 at the mRNA and protein level, but do not secrete these proteins to the culture medium. Results of western blotting demonstrated that the protein level of CD59 was regulated by IL-6 and IL-8 in a dose-dependent manner. Immunofluorescence analysis revealed that the ovarian cancer A2780 cell line expresses the membrane bound form of CD55 protein. The present results indicate that CD55 and CD59 may affect the efficiency of complement-mediated immunotherapies.

IL­6 and IL­8 enhance factor H binding to the cell membranes.

The aim of the present study was to assess the role of interleukin (IL)­6 and IL­8 on the expression of fluid­phase complement inhibitor, factor H (FH), and FH­like protein 1 (FHL­1), in the A2780 ovarian carcinoma cell line. This cell line does not normally produce IL­6, however, is IL­6 responsive due to the presence of receptor for IL­6. The presence of FH and FHL­1 in the cell lysates was confirmed by western blotting. The levels of FH and FHL­1 in the medium were determined by enzyme­linked immunosorbent assay. To evaluate gene expression, reverse transcription­quantitative polymerase chain reaction was performed. The cellular localization of FH and FHL­1 in ovarian cancer cells was assessed by immunofluorescence. The present study revealed that FH, contrary to FHL­1, was secreted by ovarian cancer cells, however, this process was independent of IL stimulation. No significant differences were observed in the concentration of FH in the control cells, when compared with the samples treated with IL­6/IL­8. The results of western blotting revealed that the protein expression levels of FH and FHL­1 were not regulated by IL­6 and IL­8 in a dose­dependent manner. Immunofluorescence analysis confirmed that the A2780 ovarian cancer cell line expressed both membrane bound and intracellular forms of FH and FHL­1. The present data revealed that the A2780 cells expressed and secreted FH protein and are also able to bind FH and FHL­1. This may influence the efficiency of complement mediated immunotherapy.

The immunohistochemical analysis of membrane-bound CD55, CD59 and fluid-phase FH and FH-like complement inhibitors in cancers of ovary and corpus uteri origin.

One of the potential therapeutic methods of cancer treatment is the immunotherapy with monoclonal antibodies. This kind of therapy, although devoid of serious side effects, has often insufficient efficacy. The presence of complement inhibitors on the cancer cells, which are able to inactivate complement-mediated immune response represents one of the main reasons for the inefficiency of such therapy. In our studies we investigated the expression of main membrane-bound and fluid-phase complement regulators: CD55, CD59 and factor H/factor H-like in tumour samples of ovarian and corpus uteri cancer. Tissue samples were collected from 50 patients and stained immunohistochemically, with the use of peroxidase-based immunodetection system. Immunohistochemical analysis revealed that complement inhibitors are present in examined tumors although their presence is heterogenous. The most prevalent is the presence of factor H/H-like, localized mostly in tumor stroma and within vascular structures. Membrane bound complement inhibitors are less prominently expressed by cancer cells. CD55 was detected in low percentage of cells, predominantly within cancer tubules. CD59 immunoreactivity was more prevalent in cancer cells, and was localized particularly at the margin of cancer cell tubules. Our results demonstrate that the most prominent complement inhibitor in cancer of ovary and corpus uteri origin is factor H/factor H-like. Blocking or downregulation of this inhibitor should be taken into consideration with regards to improving the efficiency of immunotherapy with monoclonal antibodies.

2-(3-Chloro-5,6-diphenyl-2,5-dihydro-1,2,4-triazin-5-yl)-2-methyl-propane-nitrile.

The title compound, C(19)H(17)ClN(4), was obtained from the reaction of 3-chloro-5,6-diphenyl-1,2,4-triazine with isobutyronitrile in the presence of lithium diisopropyl-amide as an unexpected product of covalent addition of isobutyronitrile carbanion to the C-5 atom of the 1,2,4-triazine ring. The 2,5-dihydro-1,2,4-triazine ring is essentially planar (r.m.s. deviation = 0.0059 Å) and the 5- and 6-phenyl substituents are inclined to its mean plane with dihedral angles of 89.97 (4) and 55.52 (5)°, respectively. Intra-molecular C-H⋯N inter-actions occur. In the crystal, mol-ecules related by a c-glide plane are linked into zigzag chains along [001] by N-H⋯N hydrogen bonds.