[Diagnosis and treatment of colorectal non-epithelial malignancies]

OBJECTIVE

To summarize the experience in the diagnosis and treatment of colorectal malignancies of non-epithelial origin.

METHODS

Seventy five cases of colorectal non-epithelial malignancy who had undergone treatment in our hospital from 1975 to 1996 were retrospectively analysed with their clinicopathologic characteristics, treatment and prognosis.

RESULTS

Patients usually had no specific clinical manifectation, such as bloody purulent stool or mucous stool. No apparent mucosa damage other than changes due to pressure from without was found on x-ray and colonoscopic examinations. Diagnosis depended on pathology and clinical manifestations. Metastasis occurred mainly by hematogenous spread and local invasion. In this series, 21 cases (6 liomyosarcomas; 15 lymphosarcoma) had local recurrence. The principle treatment was operation, which was performed two or several times in patients with local recurrences. Except lymphosarcoma, the disease was not sensitive to chemotherapy or radiotherapy. The survival rate was significantly lower than that of colorectal cancers.

CONCLUSION

The disease is apt to be misdiagnosed or missed because it lacks specific symptoms. Local recurrence and hematogenous metastasis are common.

Autoantibodies to DEK oncoprotein in human inflammatory disease

OBJECTIVE

To evaluate the specificity of anti-DEK antibodies for juvenile rheumatoid arthritis (JRA).

METHODS

Anti-DEK autoantibodies were measured by enzyme-linked immunosorbent assay (ELISA) using affinity-purified his6-DEK fusion protein. Sera from 639 subjects (417 patients with systemic autoimmune disease, 13 with sarcoidosis, 44 with pulmonary tuberculosis, 125 with uveitis, and 6 with scleritis, and 34 healthy control subjects) were screened. Reactivity was verified by immunoblotting and immunoprecipitation studies using baculovirus-expressed human DEK.

RESULTS

Anti-DEK activity was found at the following frequencies: JRA 39.4% (n = 71), systemic lupus erythematosus (SLE) 25.1% (n = 216), sarcoidosis 46.2% (n = 13), rheumatoid arthritis 15.5% (n = 71), systemic sclerosis 36.0% (n = 22), polymyositis 6.2% (n = 16), and adult Still's disease 0% (n = 21). Autoantibodies also were detected in 9.1% of tuberculosis sera (n = 44), but were undetectable in sera from the 34 healthy controls. Western blot and immunoprecipitation assay results correlated well with the ELISA findings. In general, levels of anti-DEK autoantibodies were higher in SLE than in other patient subsets, including JRA.

CONCLUSION

Anti-DEK autoantibodies are less specific for JRA than previously believed. They are produced in association with a variety of inflammatory conditions, many of which are associated with granuloma formation and/or predominant Thl cytokine production. Anti-DEK antibodies may be a marker for a subset of autoimmunity associated with interferon-gamma production rather than a particular disease subset.

Modification of the amino terminus of a class II epitope confers resistance to degradation by CD13 on dendritic cells and enhances presentation to T cells

Dendritic cells and human B cell lines were compared for ability to present synthetic peptides corresponding to residues 145-159 and 188-203 of human Ig kappa-chains to peptide-specific mouse T cell hybridomas restricted by HLA-DR4Dw4. B cell lines presented both peptides, but dendritic cells could only efficiently present the latter epitope. In this paper, we show that dendritic cells degrade the 145-159 peptide, removing four residues from the amino terminus. Binding of the peptide to the class II restriction element is not required for this process. The degradation product is resistant to further cleavage, accumulates in the culture supernatant, and does not bind to HLA-DR4Dw4 or stimulate T cell reactivity. Cleavage can be blocked with bestatin, but not with other protease inhibitors tested, or by a mAb directed against aminopeptidase N (CD13). Addition of an acetyl group to the amino terminus of peptide 145-159 also blocks degradation, and allows dendritic cells to present the peptide to specific T cells with greatly increased efficiency. These results demonstrate that CD13 on dendritic cells is able to selectively and efficiently degrade exogenously provided peptide Ags, in a process that can be blocked by addition of an acetyl group to the amino terminus of the peptide. Modification of the amino terminus of peptide epitopes susceptible to degradation may prove to be useful as a general strategy for enhancing their immunogenicity.

[Experimental study on herpes simplex virus-1 functional gene latency in cornea]

OBJECTIVE

To investigate the possible existence of herpes simplex virus-1 (HSV-1) functional gene latency in cornea.

METHODS

A herpes simplex keratitis (HSK) model was established in New Zealand White (NZW) rabbit corneas, latently infected corneas were transplanted to one eye of each naive NZW rabbit. One week after the operation, the corneal buttons were removed and divided into three portions. One portion was processed for HSV-1 antigen detection, another was for HVS-1 latency associated transcript (LAT), thymidine kinase (TK) and DNA polymerase gene detections by polymerase chain reaction (PCR), and the last portion after tissue culture for 3 weeks, it was co-cultured with rabbit kidney cells (RK) for one week, then the expression of HSV-1 antigen in the RK cells and this portion of corneal button was detected.

RESULT

In the 15 corneal samples negative for HSV-1 antigen, LAT gene was detected in 8 samples, TK gene in 10 and DNA polymerase gene in 6 samples. HSV-1 antigen was detected in 3 samples of RK cells and 6 cultured corneal samples.

CONCLUSION

HSV-1 functional genes are retained in latently infected cornea.

[No switch region is found in the regulatory sequence of HPV 16 for promoter P97]

OBJECTIVE

Cellular transcriptional regulatory factor YY1 represses the activity of the early promoter P97 of HPV 16, but the regulatory activity to early promoter P105 of HPV 18 depends on a switch region which locates at the upstream sequences of YY1 binding sites. This study is to find out whether within the HPV 16 LCR there is such motif.

METHODS

DNA sequences of the whole HPV 16 LCR region were analyzed. Two similar switch structures were found. Different CAT reporter plasmids, one containing HPV 16 reference and the other mutated LCRs, both starting at the end of L1 and from the beginning of the enhancer, were generated and transfected in HeLa cells transiently.

RESULTS

CAT assays showed there is no change of regulation pattern of YY1 on P97, when the two switch-similar structures were deleted. Sequences analysis also showed that no switch region like motif could be demonstrated in enhancer region, in promoter proximal segment, and even in E6/E7 area.

CONCLUSION

It suggests that there is no such switch region within HPV 16 transcriptional regulatory region.

Immunotherapy of NOD mice with bone marrow-derived dendritic cells

We evaluated two bone marrow-derived dendritic cell (DC) populations from NOD mice, the murine model for type 1 human diabetes. DCs derived from GM-CSF [granulocyte/macrophage colony-stimulating factor] + interleukin (IL)-4 cultures expressed high levels of major histocompatibility complex (MHC) class II, CD40, CD80, and CD86 molecules and were efficient stimulators of naive allogeneic T-cells. In contrast, DCs derived from GM-CSF cultures had low levels of MHC class II costimulation/activation molecules, were able to take up mannosylated bovine serum albumin more efficiently than GM + IL-4 DCs, and were poor T-cell stimulators. The two DC populations migrated to the spleen and pancreas after intravenous injection. To determine the ability of the two DC populations to modulate diabetes development, DCs were pulsed with a mixture of three islet antigen-derived peptides or with medium before injection into prediabetic NOD mice. Despite phenotypic and functional differences in vitro, both populations prevented in vivo diabetes development. Pulsing of the DCs with peptide in vitro did not significantly improve the ability of DCs to prevent disease, which suggests that DCs may process and present antigen to T-cells in vivo. In addition, we detected GAD65 peptide-specific IgG1 antibody responses in DC-treated mice. Overall, these results suggest that a Th2 response was generated in DC-treated mice. This response was optimal when using GM + IL-4 DCs, which suggests that the balance between regulatory Th2 and effector Th1 cells may have been altered in these mice.

Binding and uptake of agalactosyl IgG by mannose receptor on macrophages and dendritic cells

Increased levels of agalactosyl IgG (G0 IgG) are found in several autoimmune diseases, including rheumatoid arthritis, in which they are correlated with severity of the disease. To investigate whether structural alteration of IgG may lead to aberrant processing and presentation of IgG peptides as autoantigens, we have studied uptake of G0 IgG by human dendritic cells and macrophages cultured from PBMC. We found that enzymatic removal of terminal galactose residues, which exposes N-acetylglucosamine residues, increases uptake of soluble IgG mediated by mannose receptor on macrophages and dendritic cells. Efficient uptake appears to require recycling of the receptor, can be blocked by saccharides or Abs reactive with mannose receptor, and is dependent upon the state of maturation of the dendritic cells. No differences between IgG isotypes in ability to be internalized by APC were identified, suggesting that uptake would not be limited to a particular subset of Abs. These results suggest a novel pathway by which Abs or Ag-Ab complexes can be taken into dendritic cells and macrophages, and potentially generate epitopes recognized by T cells. These findings may have particular relevance for autoimmune disorders characterized by high levels of G0 IgG.

The terminal structure plays an important role in the biological activity of cecropin CMIV

Antibacterial peptides have received increasing attention as a new pharmaceutical substance. But the molecular mechanism of lysis is still poorly understood. CMIV gene and mutant CMIV gene in GST fusion system were expressed. After cleaving with different cleavage reagents, the peptide with an excess of N-terminus and with an un-amidated C-terminus stopped the activity while the peptide with an excess Asn at the C-terminus had the activity level the same as natural CMIV. The results showed that the terminal structure of cecropin CMIV played an important role in its biological activity.

Erf2, a novel gene product that affects the localization and palmitoylation of Ras2 in Saccharomyces cerevisiae

Plasma membrane localization of Ras requires posttranslational addition of farnesyl and palmitoyl lipid moieties to a C-terminal CaaX motif (C is cysteine, a is any aliphatic residue, X is the carboxy terminal residue). To better understand the relationship between posttranslational processing and the subcellular localization of Ras, a yeast genetic screen was undertaken based on the loss of function of a palmitoylation-dependent RAS2 allele. Mutations were identified in an uncharacterized open reading frame (YLR246w) that we have designated ERF2 and a previously described suppressor of hyperactive Ras, SHR5. ERF2 encodes a 41-kDa protein with four predicted transmembrane (TM) segments and a motif consisting of the amino acids Asp-His-His-Cys (DHHC) within a cysteine-rich domain (CRD), called DHHC-CRD. Mutations within the DHHC-CRD abolish Erf2 function. Subcellular fractionation and immunolocalization experiments reveal that Erf2 tagged with a triply iterated hemagglutinin epitope is an integral membrane protein that colocalizes with the yeast endoplasmic reticulum marker Kar2. Strains lacking ERF2 are viable, but they have a synthetic growth defect in the absence of RAS2 and partially suppress the heat shock sensitivity resulting from expression of the hyperactive RAS2(V19) allele. Ras2 proteins expressed in an erf2Delta strain have a reduced level of palmitoylation and are partially mislocalized to the vacuole. Based on these observations, we propose that Erf2 is a component of a previously uncharacterized Ras subcellular localization pathway. Putative members of an Erf2 family of proteins have been uncovered in yeast, plant, worm, insect, and mammalian genome databases, suggesting that Erf2 plays a role in Ras localization in all eucaryotes.

[Determination of diosgenin in Rhizoma Paridis by high performance liquid chromatography]

A method for the separation and determination of diosgenin in Rhizoma Paridis by reversed-phase high performance liquid chromatography was developed. The Rhizoma Paridis powder samples were extracted with methanol in a Soxhlet extractor. After extraction the solvent was evaporated and the extract was hydrolysed with 2 mol/L hydrochloric acid for 2 h in a boiling water bath. Then the diosgenin was extracted with petroleum ether (b.p. 60-90 degrees C). The operating conditions were Symmetry C8 column (5 microns, 3.9 mm x 150 mm) at 30 degrees C, mobile phase of V(acetonitrile):V(water) = 75:25 and UV detector at 203 nm. The linearity of the calibration curve was good in the range of 2.1-10.5 micrograms for diosgenin(r = 0.9994). The average recovery and RSD of diosgenin were 99.1% and 1.7% (n = 5) respectively. The method is accurate and reproducible and has been applied to the analysis of Rhizoma Paridis from different sources.

Identification and cloning of a negative regulator of systemic acquired resistance, SNI1, through a screen for suppressors of npr1-1

Systemic acquired resistance (SAR) is a plant immune response induced after a local infection by necrotizing pathogens. The Arabidopsis NPR1 gene is a positive regulator of SAR, essential for transducing the SAR signal salicylic acid (SA). Mutations in the NPR1 gene abolish the SA-induced expression of pathogenesis-related (PR) genes and resistance to pathogens. To identify additional regulators of SAR, we screened for suppressors of npr1-1. In the npr1-1 background, the sni1 (suppressor of npr1-1, inducible 1) mutant shows near wild-type levels of PR1 expression and resistance to pathogens after induction. Restoration of SAR in npr1-1 by the recessive sni1 mutation indicates that wild-type SNI1 may function as a negative regulator of SAR. We cloned the SNI1 gene and found that it encodes a leucine-rich nuclear protein.

[Measurement of retinal nerve fiber layer thickness of normal eyes with nerve fiber analyzer]

OBJECTIVE

To study the retinal nerve fiber layer thickness (RNFLT) of normal eye and the correlation with age.

METHODS

RNFLT of 198 cases of normal eyes were examined by using nerve fiber analyzer (NFA).

RESULTS

There were significant inverse linear correlation between the RNFLT and age (r = -0.46, P < 0.01). In the analysis by the quadrant, the RNFLT was correlated with age in the superior and inferior quadrant. The mean ratio of superior and inferior quadrant thickness (S/I) was 1.041.

CONCLUSION

NFA seems to be an useful tool to measure the RNFLT quantitatively. The RNFLT of normal eye is found to be decreased with age.

[Expression of human prp gene in prokaryotic cells using GST fusion protein expression system]

OBJECTIVE

To study the biological features of cell-surface protein PrPc, which is thought to be involved in the prion-associated diseases after converting to a proteinase-resistant isoform PrPSc posttranslationally, and to establish an effective immunologic diagnostic method using PrPc as antigen.

METHODS

Amplifying and cloning the human prp gene from lymphocytes of two normal Chinese, after confirmed by DNA sequence analysis, the genes were separately subcloned into a GST-fusion expression plasmid.

RESULTS

Sequence analysis showed that one contatined a point mutation that induced the 65th amino acid "Trp" inverting to a stop codon "TAG", whereas the other had the same sequence as the published standard prp gene. Both the standard and the mutated prp genes were separately subcloned into a GST fusion protein expression vector and expressed in the prokaryotic cells effectively. Western blot assay revealed that both of them expressed GST-PrP fusion proteins and could be recognized by PrP specific monoclonal antibody.

CONCLUSION

It suggests that human PrP protein can be expressed in the GST fusion protein expression system and the expressed proteins hold good immune-reactivity.

SSA/Ro antigen expressed on membrane of UVB-induced apoptotic keratinocytes is pathogenic but not detectable in supernatant of cell culture

OBJECTIVES

To better understand the potential effect of ultraviolet light on the photosensitivity of patients with lupus erythematosus (LE), to elucidate the mechanisms of SSA/Ro antibody formation after UV exposure, and to investigate the role of this autoantibody in the pathogenesis of skin lesions.

METHODS

Primary human keratinocytes were cultured in Medium-154. After ultraviolet-B light (UVB) irradiation, the keratinocytes were treated with affinity-purified anti-SSA/Ro sera and stained with FITC-labeled goat-anti-human IgG and propidium iodide (PI), followed by enzyme digestion with RNase, RNase-free DNase or RNase plus DNase. As target cells, the irradiated keratinocytes were incubated with affinity-purified anti-SSA/Ro sera, with or without fresh human sera as complement. The supernatants of irradiated keratinocytes were analyzed with ELISA method for SSA/Ro antigens.

RESULTS

UVB irradiation induced apoptotic blebs on the cell surface. The blebs were composed of ribonucleoproteins and contained SSA/Ro antigens. SSA/Ro antigens expressed on UVB irradiated keratinocytes bound to affinity-purified anti-SSA/Ro sera, leading to complement-dependent cytotoxicity. However, no SSA/Ro antigens were detected in the supernatants.

CONCLUSIONS

SSA/Ro, a ribonucleoprotein antigen expressed on UVB irradiated keratinocytes, may be recognized and presented to immune cells by a direct cell-cell contact other than be eliminated into the circulation.

Interaction of NPR1 with basic leucine zipper protein transcription factors that bind sequences required for salicylic acid induction of the PR-1 gene

The Arabidopsis thaliana NPR1 has been shown to be a key regulator of gene expression during the onset of a plant disease-resistance response known as systemic acquired resistance. The npr1 mutant plants fail to respond to systemic acquired resistance-inducing signals such as salicylic acid (SA), or express SA-induced pathogenesis-related (PR) genes. Using NPR1 as bait in a yeast two-hybrid screen, we identified a subclass of transcription factors in the basic leucine zipper protein family (AHBP-1b and TGA6) and showed that they interact specifically in yeast and in vitro with NPR1. Point mutations that abolish the NPR1 function in A. thaliana also impair the interactions between NPR1 and the transcription factors in the yeast two-hybrid assay. Furthermore, a gel mobility shift assay showed that the purified transcription factor protein, AHBP-1b, binds specifically to an SA-responsive promoter element of the A. thaliana PR-1 gene. These data suggest that NPR1 may regulate PR-1 gene expression by interacting with a subclass of basic leucine zipper protein transcription factors.

Solid-phase synthesis of a combinatorial array of 1,3-bis(acylamino)-2-butanones, inhibitors of the cysteine proteases cathepsins K and L

To more rapidly prepare members of the 1,3-bis(acylamino)-2-butanone class of cysteine protease inhibitors, a solid-phase synthesis was developed. 1-Azido-3-amino-2,2-dimethoxybutane (4), which has the two amino groups differentiated and the ketone protected as a a ketal, served as a surrogate for the 1,3-diamino-2-butanone core. Amine (4) was coupled to the BAL-resin-linked carboxylic acids derived from alpha-amino acid esters. Evaluation of a small combinatorial array by measuring inhibition constants (Ki,appS) against cathepsins K, L, and B provided some structure-activity relationship trends with respect to selectivity and potency. Novel, potent inhibitors of cathepsins K and L were identified.

ebi regulates epidermal growth factor receptor signaling pathways in Drosophila

ebi regulates the epidermal growth factor receptor (EGFR) signaling pathway at multiple steps in Drosophila development. Mutations in ebi and Egfr lead to similar phenotypes and show genetic interactions. However, ebi does not show genetic interactions with other RTKs (e.g., torso) or with components of the canonical Ras/MAP kinase pathway. ebi encodes an evolutionarily conserved protein with a unique amino terminus, distantly related to F-box sequences, and six tandemly arranged carboxy-terminal WD40 repeats. The existence of closely related proteins in yeast, plants, and humans suggests that ebi functions in a highly conserved biochemical pathway. Proteins with related structures regulate protein degradation. Similarly, in the developing eye, ebi promotes EGFR-dependent down-regulation of Tramtrack88, an antagonist of neuronal development.

Concurrent inhibition and excitation of phrenic motoneurons during inspiration: phase-specific control of excitability

The movements that define behavior are controlled by motoneuron output, which depends on the excitability of motoneurons and the synaptic inputs they receive. Modulation of motoneuron excitability takes place over many time scales. To determine whether motoneuron excitability is specifically modulated during the active versus the quiescent phase of rhythmic behavior, we compared the input-output properties of phrenic motoneurons (PMNs) during inspiratory and expiratory phases of respiration. In neonatal rat brainstem-spinal cord preparations that generate rhythmic respiratory motor outflow, we blocked excitatory inspiratory synaptic drive to PMNs and then examined their phase-dependent responses to superthreshold current pulses. Pulses during inspiration elicited fewer action potentials compared with identical pulses during expiration. This reduced excitability arose from an inspiratory-phase inhibitory input that hyperpolarized PMNs in the absence of excitatory inspiratory inputs. Local application of bicuculline blocked this inhibition as well as the difference between inspiratory and expiratory firing. Correspondingly, bicuculline locally applied to the midcervical spinal cord enhanced fourth cervical nerve (C4) inspiratory burst amplitude. Strychnine had no effect on C4 output. Nicotinic receptor antagonists neither potentiated C4 output nor blocked its potentiation by bicuculline, further indicating that the inhibition is not from recurrent inhibitory pathways. We conclude that it is bulbospinal in origin. These data demonstrate that rapid changes in motoneuron excitability occur during behavior and suggest that integration of overlapping, opposing synaptic inputs to motoneurons is important in controlling motor outflow. Modulation of phasic inhibition may represent a means for regulating the transfer function of PMNs to suit behavioral demands.

[Removal of YY1 binding sites in HPV 16 LCR increases viral transforming activities on mouse fibroblasts]

OBJECTIVE

To study the effect of removal of YY1 binding sites within the LCR region of HPV 16 on viral transforming activity.

METHODS

Previously we had generated new plasmids carrying HPV 16 whole genome, which contained naturally occurred mutated LCR sequences. The viral transforming abilities on mouse fibroblasts were evaluated in anchorage-independent assays, while the expression and activity of YY1 protein in fibroblasts were tested with EMSA and luciferase assays.

RESULTS

YY1 protein was expressed in mouse fibroblasts C127, with ability for DNA binding and repression on P97 activity. Both HPV 16 wild-type DNA and mutated DNAs were transfected into C127 cells and spread to the soft-agarose mediums after selecting with G 418. The growth numbers of the cells transfected with mutated HPV 16 DNAs were 2-10 fold more than that with wild-type HPV 16 DNA.

CONCLUSION

Like in epithelial cells or cell lines, transcription regulator YY1 is widely expressed in rodent fibroblasts. Removal of YY1 binding motifs can elevate in the context of the whole genome, the anchorage independent growth ability and the transforming capacity of HPV 16 on the mouse fibroblasts.

[Phacoemulsification and posterior chamber intraocular lens implantation in high myopia]

OBJECTIVE

To evaluate the therapeutic effect of phacoemulsification and posterior chamber intraocular lens (IOL) implantation in high myopia.

METHODS

Phacoemulsification with implantation of a foldable IOL or a PMMA rigid IOL was performed on 28 eyes of 21 patients with senile, complicated or congenital cataracts through a 3.2 mm small scleral tunnel incision or through a 5.5 mm incision respectively. The average age of the patients was 51.32 years (21 - 70 years). The mean axial length was (27.56 +/- 1.21) mm (26.00 - 33.41 mm). The mean keratometry was (43.38 +/- 1.36) D (42.00 - 46.54 D). The mean diopter of IOL was (+ 9.59 +/- 3.65) D (+ 4.00 - + 15.00 D).

RESULTS

Postoperatively, the uncorrected or corrected visual acuity 0.5 or better at 1 day, 1 week, 1 month and 3 months was in 63.6%, 86.4%, 95.5% and 95.2% patients respectively; the patients having achieved the best visual acuity of 1.0 or better were accounted for 9.1%, 31.8%, 50.0% and 57.1% respectively.

CONCLUSIONS

Phacoemulsification and the posterior chamber IOL implantation offers the advantages of rapid and better rehabilitation of visual acuity and more stabilization of postoperative astigmatism in patients with high myopia; whereas for eyes with the axial lengths over 30 mm, the recovery of the visual acuity was less satisfactory.

[The present research situation of cause of formation of impedance cardiograph waveform]

This paper summarized the present research situation of cause of formation of impedance cardiograph waveform in two aspects of early and current research on it by the means of consulting a great deal of domestic and foreign data. The paper pointed out that a practicable way for correcting Kubicek theory and its physical model, making SV formula more accurate is to apply finite element technology to the research field under the guide of impedance cardiograph electric field theory. At the same time, the paper made preliminary introduction on the author's research work in the area.

A model for Ku heterodimer assembly and interaction with DNA. Implications for the function of Ku antigen

Ku autoantigen, a heterodimer of 70- and 80-kDa subunits, is a DNA end-binding factor critical for DNA repair. Two domains of p70 mediate DNA binding, one on the C-terminal and one on the N-terminal portion. The latter must dimerize with p80 in order to bind DNA, whereas the former is p80-independent. Both must be intact for end binding activity in gel shift assays. To evaluate the role of p80 in DNA binding, deletion mutants were co-expressed with full-length p70 using recombinant baculoviruses. We show by several criteria that amino acids 371-510 of p80 interact with p70. Both of the p70 dimerization domains bind to the same region of p80, but apparently to separate sites within that region. In DNA immunoprecipitation assays, amino acids 179-510 of p80 were required for p80-dependent DNA binding of p70, whereas in gel shift assays, amino acids 179-732 were necessary. Interestingly, both the p80-dependent and the p80-independent DNA binding sites preferentially bound to DNA ends, suggesting a model in which a single Ku heterodimer may juxtapose two broken DNA ends physically, facilitating their rejoining by DNA ligases.

Fusion of macrophages on an implant surface is associated with down-regulated expression of ligands for galectin-1 and -3 in the rat

Galectins have a wide range of biological activities which are elicited by binding to appropriate glycoligands. Besides regulation of the expression of the galectins the extent of the presence of suitable binding sites will be relevant to infer the cellular responsiveness to this class of sugar receptors. Thus ligand presentation requires monitoring by the tissue lectin. We demonstrate the expression of galectin-3 by macrophages and foreign-body giant multinucleate cells colonizing a cellophane implant in the rat by the A1D6 monoclonal antibody. The extents of ligand presence are visualized in the same cells by biotinylated galectin-3 and also by galectin-1 which is produced by diverse mammalian cell types and widely distributed. Labeled mistletoe (VAA) and tomato (LEA) lectins are used as tools to assess the degree of similarity of the binding profile between endogenous and exogenous proteins. The presentation of alpha-galactosides is monitored with a natural immunoglobulin G subfraction obtained by two consecutive affinity chromatography steps. The binding of labeled galectins and plant lectins was significantly lower to foreign-body giant multinucleate cells than to mononuclear macrophages. The application of the alpha-galactoside-specific probe yielded no significant staining. The potential problem of epitope accessibility could be excluded by the concomitant positivity obtained with an IgG subfraction with selectivity to beta-galactosides also obtained by affinity chromatography. These results provide no evidence for a role of alpha-galactosides for the binding of galectins in the rat macrophages colonizing the implant. The reduced level of expression of glycoligands for galectin-1 and -3 in foreign-body giant multinucleate cells in contrast with the mononuclear macrophages suggests an inhibitory influence of macrophage fusion on the expression of galectin-reactive molecules.

Prodrugs of anthracyclines for use in antibody-directed enzyme prodrug therapy

A series of new prodrugs of daunorubicin and doxorubicin which are candidates for antibody-directed enzyme prodrug therapy (ADEPT) is reported. These compounds (25a,b,c and 32a,b,c) have been designed to generate cytotoxic drugs after activation with beta-glucuronidase. As expected, recovery of the active drug was observed after enzymatic cleavage by Escherichia coli beta-glucuronidase as well as by a fusion protein which has been obtained from human beta-glucuronidase and humanized CEA-specific binding region. The six prodrugs are highly stable and are more than 100-fold less cytotoxic than doxorubicin against murine L1210 cell lines. The ortho-substituted phenyl carbamates 25a,b,c are better substrates for beta-glucuronidase than the corresponding para-substituted analogues. After taking into account additional factors such as stability in plasma and kinetics of enzymatic cleavage, we selected the o-nitro prodrug 25c for clinical trials.