Mismatch repair protein MSH2 expression and prognosis of colorectal cancer patients

INTRODUCTION AND AIMS

The role of genetic factors in the etiology and prognosis of patients with sporadic colorectal cancer is controversial. We have therefore investigated the biological and clinicopathological influence of immunohistochemical MSH2 expression in colorectal cancer.

PATIENTS AND METHODS

A total of 49 consecutive patients with unselected colorectal cancer operated on in our unit were included in the study. All tumors were resected and tumor specimens were evaluated for MSH2 expression. Clinicopathological data and patient survival were correlated with MSH2 staining. Uni- and multivariate analyses were performed. The minimum follow-up period was five years.

RESULTS

Curative resection was performed in 34 patients (64.9%), 14 of whom subsequently relapsed. At the end of the overall follow-up 25 (51%) patients had died, 21 of cancer-related causes. Twenty-eight patients (57.1%) were negative for MSH2 staining. Only vascular invasion was significantly correlated with MSH2 expression (lower median values; p=0.04). The overall median survival was 47.9 months (95% CI=27-86.6%). Multivariate analysis of variables in relation to survival showed that T stage (p=0.001), N stage (p<0.001) and MSH2 expression (p=0.01) were independent factors for survival.

CONCLUSIONS

Reduced MSH2 expression is frequent in unselected colorectal cancer patients. Only vascular invasion was correlated with MSH2 expression in this study. Survival was related to TN stage and MSH2 staining.

Bcl-2 family gene modulation during spontaneous apoptosis of B-chronic lymphocytic leukemia cells

Malignant cell accumulation in B-cell chronic lymphocytic leukemia (B-CLL) is primarily caused by defective apoptosis rather than increased proliferation. To further understand the role of Bcl-2 family members, known regulators of apoptosis, in the abnormal B-CLL survival, we have measured their mRNA levels in fresh B-CLL cells and in cultures undergoing spontaneous apoptosis. Using RNA protection assays we found constitutive expression of most bcl-2 members with high levels of bcl2, bcl-w, bad, bak, bax, and the bcl-2/bax ratio, compared to normal PBL. Spontaneous apoptosis of B-CLL cells by in vitro culture resulted in decreased bcl-2, bcl-w, bfl-1, mcl-1, bak, bax, and bcl-2/bax expression. The pro-apoptotic member bik was only expressed in 5/19 cases and was not modulated during apoptosis, suggesting that bik is not involved in this process. Thus, several Bcl-2 family genes are regulated during B-CLL spontaneous apoptosis and their relative levels may contribute to in vivo progression of the disease.

Antibodies and gene therapy: teaching old ‘magic bullets’ new tricks

The emergence of recombinant technologies has revolutionized the selection and production of monoclonal antibodies, allowing the design of fully human antibodies of any specificity and for diverse purposes. Recombinant antibodies can be engineered with optimized properties, such as antigen-binding affinity, molecular architecture and dimerization state, and fused with a vast array of effector moieties to enhance their tumor-targeting ability and potency. The use of gene therapy methods offers additional benefits by achieving sustained and effective concentrations of therapeutic antibodies directly at points of target intervention. This compensates for the rapid blood clearance of antibody fragments and could make the antibody less immunogenic and better tolerated. Furthermore, genetic approaches provide antibody molecules with new functions in unexpected scenarios: expression of antibody domains in precise intracellular locations and grafting of new binding activities to engineered cells. The relevance of these and other emerging concepts for antibody-based cancer therapy is discussed.

Generation of non-permissive basement membranes by anti-laminin antibody fragments produced by matrix-embedded gene-modified cells

Tumor-induced blood vessel formation is a key process for the growth and spread of solid tumors, traditionally attributed to activated host endothelial cells (angiogenesis). Recently, highly aggressive cancer cells have been shown to form vascular channels in the absence of endothelial cells (vasculogenic mimicry). In this work, we have focused on the common dependence of both processes in their interactions with the surrounding extracellular matrix. We had previously described a human recombinant anti-laminin antibody that blocked the capillary morphogenesis of human endothelial cells. Here, we demonstrate that the purified antibody is capable of inhibiting channel formation by human cancer cells, suggesting a common morphogenic pathway in both processes. Moreover, matrix-embedded cells producing antibody fragments may render the surrounding matrix non-permissive for aggressive tumor cells. These results open the way for the development of new therapeutic strategies for cancer.

Ordered quantization and the Ehrenfest time scale

We propose a prescription to quantize classical monomials in terms of symmetric and ordered expansions of noncommuting operators of a bosonic theory. As a direct application of such quantization rules, we quantize a classically time evolved function O(q,p,t), and calculate its expectation value in coherent states. The result can be expressed in terms of the application of a classical operator that performs a Gaussian smoothing of the original function O evaluated at the center of the coherent state. This scheme produces a natural semiclassical expansion for the quantum expectation values at a short time scale. Moreover, since the classical Liouville evolution of a Gaussian probability density gives the same form for the classical statistical mean value, we can calculate the first-order correction in h entirely from the associated classical time evolved function. This allows us to write a general expression for the Ehrenfest time in terms of the departure of the centroid of the quantum distribution from the classical trajectory, provided we start with an initially coherent state for each subsystem. In order to illustrate this approach, we have calculated analytically the Ehrenfest time of a model with N-coupled nonlinear oscillators with nonlinearity of even order.

The extracellular matrix: a new turn-of-the-screw for anti-angiogenic strategies

Anti-angiogenic therapy is currently one of most active fields in cancer research. The initial strategies, which were aimed at inhibiting tumor vascularization, included upregulation of endogenous inhibitors and blocking of the signals delivered by angiogenic factors. However, interactions between endothelial cells and their surrounding extracellular matrix also play a crucial role in modulation of the angiogenic process. Compounds that target either the integrins implicated in these interactions or the proteases responsible for matrix remodeling have been shown to halt tumor growth in murine models and are now in clinical trials. However, little attention has been paid to integrin ligands, the extracellular matrix components that support endothelial cell survival, movement and reorganization. Here, we summarize the current knowledge about these angiogenesis inhibitors and propose a novel therapeutic approach based on the blocking of crucial binding sites present in the extracellular matrix.

A novel cell binding site in the coiled-coil domain of laminin involved in capillary morphogenesis

Recently, we reported the isolation and characterization of an anti-laminin antibody that modulates the extracellular matrix-dependent morphogenesis of endothelial cells. Here we use this antibody to precisely map the binding site responsible for mediating this biologically important interaction. By using a phage display-assisted mapping strategy to preserve protein structure, we demonstrate for the first time that the coiled-coil region of laminin contains a cell binding site. The adhesion motif is formed by residues contributed by both alpha and gamma chains, and is located in the middle part of the rod-like portion in a highly flexible area, which corresponds to a protease-susceptible site. Based on this information, a peptide mimotope was used to characterize the cognate receptor. Although we can not rule out the implication of other receptors, our results demonstrate that the laminin helical rod active site interacts with alpha2beta1 integrin on the surface of endothelial cells. These findings provide new insight into the complex mechanisms regulating capillary morphogenesis.

Clinical significance of the epidermal growth factor receptor and HER2 receptor in resectable gastric cancer

BACKGROUND

Epidermal growth factor receptor (EGFR or HER1) and its homolog c-erbB-2 (HER2) are membrane receptors. Both EGFR and HER2 genes are overexpressed in a variety of solid human cancers and are related to poor prognosis of the patients. The objective of this work was to evaluate the EGFR and HER2 contents in resectable gastric cancer, their possible relationship with clinicopathologic parameters of tumors, and their prognostic significance.

METHODS

This was a prospective analysis of 63 patients with resectable gastric carcinomas, with a mean follow-up period of 40.7 months. Membranous EGFR levels were examined by radioligand binding assays, and cytosolic HER2 levels were examined by means of an immunoenzymatic assay.

RESULTS

There was a wide variability of EGFR (1-1,239 fmol/mg of protein) and HER2 (7-20,863 NHU/mg of protein) levels in tumors. There was no significant correlation between these levels and patient or tumor characteristics. However, high levels of EGFR and HER2 were significantly associated with a shorter overall survival period (P =.03 and P =.02, respectively).

CONCLUSIONS

There is a wide variability in membranous EGFR levels and in cytosolic HER2 levels in gastric cancer, which seems to be related to the biological heterogeneity of these tumors. In addition, high tumor EGFR and HER2 levels were associated with an unfavorable outcome in patients with resectable gastric cancer.

Single-chain antibody-based gene therapy: inhibition of tumor growth by in situ production of phage-derived human antibody fragments blocking functionally active sites of cell-associated matrices

Experimental evidence suggests that blocking the interactions between endothelial cells and extracellular matrix (ECM) components may provide a potent and general strategy to inhibit tumor neovascularization. Based on these considerations, we have focused our efforts on laminin, component of the vascular basement membrane of every tumor-associated vessel, which serves an essential role in tube formation. We screened anti-laminin single-chain antibody fragments (scFv) derived from a human phage-display library and identified one that blocks the formation of capillary-like structures in vitro. This scFv inhibits angiogenesis in vivo in the chick embryo chorioallantoic membrane assay and prevents the establishment and growth of subcutaneous tumors in mice, either when administered as bolus protein therapy or when produced locally by gene-modified tumor cells. Our work represents the first demonstration of a direct in vivo therapeutic effect of a single-chain antibody secreted by gene-modified mammalian cells. These results open the way for a new antibody-based gene therapy strategy of cancer.

Linear discrete population models with two time scales in fast changing environments I: autonomous case

In this work we consider a structured population with groups and subgroups of individuals. The intra-group dynamics is assumed to be fast in comparison with the inter-group dynamics. We study linear discrete models where the slow dynamics is represented by a single matrix and the fast dynamics is described by means of the first k terms of a converging sequence of different matrices. The number k can be interpreted as the ratio between the two time scales. The aim of this work is to extend aggregation techniques to the case of fast changing environments. The main idea of aggregation is to build up a new system, with lower dimension, that summarizes the information concerning the fast process. This "aggregated" system provides essential information on the original one. It is shown that the asymptotic behavior of the original system can be approximated by the asymptotic behavior of the aggregated system when the ratio between the two time scales is large enough. We present an example of an age structured population in a patchy environment. The migration process is assumed to be fast in comparison with the demographic process. Numerical simulations illustrate that the asymptotic growth rate and the stable age distribution of the population in the original and the aggregated systems are getting closer as the ratio k increases.

Prognostic significance of tissue-type plasminogen activator (tPA) content in gastric cancer and surrounding mucosa

AIMS

We analyzed the tPA content in primary gastric carcinomas and surrounding mucosa in order to assess the relationship between tPA content, clinicopathological tumor characteristics, and estrogen and progesterone receptor content. We evaluated the prognostic value of this serine protease in gastric cancer patients.

PATIENTS AND METHODS

122 resected gastric neoplasms and 95 adjacent mucosa samples were studied. The tPA content was measured in cytosol by an ELISA method. Cytosolic ER and PgR were measured with a solid phase enzyme immunoassay.

RESULTS

Cytosolic tPA levels in neoplastic tissues (median 1.0 ng/mg prot) were significantly lower (p=0.002) than those found in paired mucosa samples (median 2.3 ng/mg prot). There was no significant association between tPA levels and clinicopathological parameters or PgR content, but tPA levels were significantly correlated with ER content. The intermediate-tPA-content group, corresponding to samples with between 0.3 and 1.70 ng/mg protein, proved to have a significantly high risk of relapse.

CONCLUSIONS

We found a wide variability in tPA levels in gastric carcinoma and adjacent mucosa samples, with significantly decreased levels in tumors and a significantly positive relationship between tPA levels and ER status. There was a non-monotonic relationship between tPA levels and prognosis in patients with gastric cancer.

Development of a computer-assisted high-throughput screening platform for anti-angiogenic testing

Angiogenesis is widely accepted to play a central role in tumor growth and spreading. Therefore, anti-angiogenic agents appear as promising tools in cancer therapy, and great efforts have been devoted to their identification in recent years. Despite fast progress in this area, a quantitative and objective system for rapid anti-angiogenic testing is not currently available. In this work, we describe a new platform for the large-scale screening of agents with potential anti-angiogenic activity. This involved the miniaturization of an in vitro two-dimensional assay model of vascular morphogenesis to run in a high-density format (384- or 1536-well microplates) and the development of a specific digital image-analysis system for the automated and quantitative evaluation of biological activity. To test the efficacy and reproducibility of the platform, we used a wide variety of well-characterized angiogenesis inhibitors, including antibodies against components of the extracellular matrix, peptides, and chemicals. The system proved to be a reproducible, polyvalent, and powerful tool for massive screening of agents with potential application in cancer therapy. Ongoing developmental work, directed toward optimizing this system for use with a fully automated high-throughput screening platform, should accelerate research into the mechanisms of tumor angiogenesis and the development of drugs that target the essential tumor vasculature.

Engagement of alpha4beta1 integrin by fibronectin induces in vitro resistance of B chronic lymphocytic leukemia cells to fludarabine

B-cell chronic lymphocytic leukemia is characterized by the accumulation of malignant B lymphocytes as a result of abnormal survival signals operating in vivo. Previously, we showed that adhesion of B-CLL cells to the fibronectin fragment H89, a ligand for alpha4beta1 integrin, prevents their spontaneous apoptosis in vitro. We have now studied whether alpha4beta1/H89 interaction affected the response of B-CLL cells to the therapeutic drug fludarabine. B-CLL cells cultured on H89 during treatment with fludarabine showed significantly higher mean viability (P<0.05) than cells cultured on the control polylysine for all doses of drug tested. Similar results were obtained with the EHEB cell line. Analysis of the expression of Bcl-2-family proteins after 48 h of fludarabine treatment revealed that Bcl-xL levels were significantly higher (P<0.05) for cells cultured on H89 than on polylysine and correlated (r=0.56, P<0.05) with the increased cell viability observed on H89 cultures. These results indicate that Bcl-xL is involved in the survival signals induced by alpha4beta1 ligation and may contribute to the progressive drug resistance observed in B-CLL.

Generation and characterization of recombinant human antibodies specific for native laminin epitopes: potential application in cancer therapy

Laminins are specific cellular regulators that directly and indirectly control activities such as cell attachment and migration, differentiation and polarity, proliferation and apoptosis, and protease expression. Considering the centrality of these issues to tumor progression, the generation of human-derived antibody fragments able to modulate laminin-regulated biological functions would allow the development of new strategies to improve treatment of cancer patients. In this report, we explore the use of phage display technology to isolate human anti-laminin antibody fragments. A library of single chain antibodies was selected using intact mouse laminin, and five different clones were identified. All the antibodies were specific for their cognate antigen, as revealed by lack of cross-reactivity with other components of the basement membranes. A more extensive characterization of the panel indicated that these antibodies recognize the native protein through conformational epitopes. All of them reduced tumor cell attachment to laminin, suggesting that domains of the laminin molecule that are recognized by these antibodies likely bind to cell-surface receptors. The antibody fragments bind to mouse, rat and human laminin. and show strong immunohistochemical reactivity with basement membranes in human and murine tissue sections. Their properties make them ideal candidates for in vivo applications.

Single and multiple pyogenic liver abscesses: etiology, clinical course, and outcome

BACKGROUND

Pyogenic liver abscesses are uncommon but they still carry a high mortality rate when encountered. This study was undertaken to evaluate the differences in the clinical behaviour of patients with single and multiple abscesses.

METHODS

From January 1985 to December 1997, 133 patients with this disease were treated in the surgical departments of five hospitals, 97 had a single abscess and 36 had multiple abscesses. Clinical features, methods of treatment, and outcome were assessed and compared in both types of abscesses.

RESULTS

A biliary origin from ascending cholangitis was most frequently found in multiple abscesses (p = 0.007). Mean age and duration of symptoms were higher in multiple lesions (p = 0.03 and p = 0.001). High levels of alkaline phosphatase were more frequently seen in multiple abscesses than in solitary ones (p = 0.02). They were both most frequently located on the right side. Antibiotic therapy alone was most frequently used in multiple abscesses (p = 0.01). Mortality rate was also higher in this type of patients (p = 0.01). The abscess-related morbidity rate was higher in multiple lesions as well but the statistical difference was not significant.

CONCLUSIONS

These results suggest that multiple liver abscesses comprise a disease of biliary origin, higher age, longer symptomatic periods, and also higher mortality rate than in single abscess.

Targeted disruption of the zetaPKC gene results in the impairment of the NF-kappaB pathway

Here we have addressed the role that zetaPKC plays in NF-kappaB activation using mice in which this kinase was inactivated by homologous recombination. These mice, although grossly normal, showed phenotypic alterations in secondary lymphoid organs reminiscent of those of the TNF receptor-1 and of the lymphotoxin-beta receptor gene-deficient mice. The lack of zetaPKC in embryonic fibroblasts (EFs) severely impairs kappaB-dependent transcriptional activity as well as cytokine-induced phosphorylation of p65. Also, a cytokine-inducible interaction of zetaPKC with p65 was detected which requires the previous degradation of IkappaB. Although in zetaPKC-/- EFs this kinase is not necessary for IKK activation, in lung, which abundantly expresses zetaPKC, IKK activation is inhibited.

The class II tumor-suppressor gene RARRES3 is expressed in B cell lymphocytic leukemias and down-regulated with disease progression

The molecular pathogenesis of B cell chronic lymphocytic leukemia (B-CLL), the most common form of leukemia, remains unknown. We have used the mRNA differential display technique to analyze genes that may be involved in the development/progression of B-CLL. We have identified the tumor suppressor retinoic acid receptor responder 3 (RARRES3) as a B-CLL-related gene. RARRES3 maps to chromosome band 11q23, a region frequently deleted in lymphoproliferative disorders. To assess the potential involvement of RARRES3 in leukemogenesis, we examined 24 cases of B-CLL, 10 of acute lymphocytic leukemia (ALL) and five related cell lines by RT-PCR and sequence analyses. We report a correlation between RARRES3 down-regulation and B-CLL progression. We also found decreased RARRES3 gene levels in ALL cases and in the five cell lines studied. We did not find mutations in any of the leukemia samples assayed, including those with 11q23 deletion. These results indicate that RARRES3 may play a role in B-CLL progression.

Purification, crystallization and identification by X-ray analysis of a prostate kallikrein from horse seminal plasma

The purification, crystallization and identification by X-ray diffraction analysis of a horse kallikrein is reported. The protein was purified from horse seminal plasma. Crystals belong to space group C2 and the structure was solved by the MIRAS method, with two heavy-atom derivatives of mercury and platinum. X-ray diffraction data to 1.42 A resolution were collected at the ESRF synchrotron-radiation source.

Clinical course, treatment, and multivariate analysis of risk factors for pyogenic liver abscess

BACKGROUND

Pyogenic liver abscess is a threatening condition. The purpose of this study was to audit the clinical behavior and to analyze the risk factors.

METHODS

One hundred and thirty-three patients treated in five hospitals during the years 1985 to 1997 were studied. By univariate and multivariate analysis we tried to identify any risk factor associated with complicated clinical course and complicated-related clinical course, and with hospital mortality.

RESULTS

Sixty-three patients (47%) were subjected to a percutaneous drainage, 45 (34%) were treated by open surgical drainage, and the remaining 25 cases (19%) received antibiotic therapy alone. Prognostic variables for a complicated clinical course were the presence of shock, low hemoglobin level, elevated prothrombin time, and polymicrobial infection. Shock, distress, low hemoglobin level, increased creatinine, and positive blood culture were significant predictors of a complicated-related clinical course. Concerning mortality, a biliary origin, shock, multiple abscesses, low hemoglobin level, and high concentration of blood urea nitrogen were independent predictors.

CONCLUSIONS

Treatment of pyogenic liver abscesses should be tailored to each patient, however, the majority of them can be successfully treated with antibiotics and percutaneous methods. Those with signs of organ failure or septicemia should preferably be managed in the intensive care unit.

Pyogenic liver abscesses: a comparison of older and younger patients

BACKGROUND

Pyogenic liver abscess is a life-threatening disease. Few studies have specifically explored the way in which the clinical features and management of elderly patients with pyogenic liver abscess differ from those of younger individuals.

METHODS

A retrospective study was undertaken to evaluate whether older patients with pyogenic liver abscess have distinctive presenting features or whether their management and outcome differ from that of younger patients. A total of 133 patients with liver abscess treated in five hospitals during 13 years comprised two groups: 78 patients aged 60 years or above (older group) and 55 patients below age 60 years (younger group). Clinical features, laboratory data, imaging and microbiological findings, management and outcome were determined in each group.

RESULTS

The older group contained more patients with associated diseases (p=0.03), nausea and vomiting at presentation (p=0.02), higher APACHE II (Acute Physiological and Chronic Health Evaluation II scale) score (p<0.001) and blood urea nitrogen (p<0.001) and serum creatinine levels (p=0.002). Multiple abscess (p=0.05) and bilobar (p=0.03) abscess were also commoner in this group. By contrast, in the younger group men predominated (p=0.01), and there was a higher overall complication rate (p=0.05).Time to diagnosis, hospital mortality rate and other variables analysed were similar in both groups.

DISCUSSION

Elderly patients with pyogenic liver abscess have some subtle differences in clinical and laboratory presentation, but these do not appear to delay diagnosis. Active management is tolerated well, with a lower morbidity rate than in younger patients and no difference in the mortality rate.

HLA class I and class II allele distribution in the Peruvian population

The distribution of HLA-A, -B, -C, -DRB1 and -DQB1 alleles in the Peruvian population was studied and compared with those of other populations in order to provide further information about their anthropological origin. Our data are consistent with the Mestizo character of this population. In terms of genetic distance Peruvians are closest to Bolivians, which is in agreement with the geographical location and the cultural and anthropological background of the two human groups. Several HLA-B alleles originally described in genetically isolated Amerindian tribes are also present in the sample studied here. This fact and the reported finding of these alleles in several Amerindian groups suggests that they were present in the first wave of humans that populated South America (Paleoindians) before they split to give rise to the different South American tribes.

Correlation of central venous pressure with Doppler waveform of the common femoral veins

The objects of this prospective study were to determine the nature of the flow in the right femoral vein and to correlate the flow velocity with the venous pressure measured in the right atrium. We performed 236 pulsed Doppler ultrasonographic examinations in 1 year on patients with a venous catheter with the distal tip in the right atrium. In the Doppler wave readouts we analyzed wave frequency, velocity components, and relationships among them and the existence of pulsatile flow. These parameters were then compared to the right atrium pressure. We investigated the correlation between the atrium pressure and the flow velocity obtained from the Doppler waveforms of the common femoral veins, obtaining a significant correlation (P<0.0001) with the following: the atrium systolic wave a, the atrium diastolic wave v, the pulsatility ratio (PR = Vmin/Vmax) and the pulsatility index (PI = [Vmax - Vmin] /Vavg). The receiver operating characteristic showed that the pulsed Doppler ultrasonography is not a sensitive technique in diagnosis high atrium pressures. In addition, both cardiac and respiratory phasicity of the venous wave was observed. A significant inverse relation was found between the pulsatile flow and high atrium pressure. Nonetheless, the low sensitivity of this technique does not allow the use of pulsatile Doppler ultrasonography in the common femoral vein for diagnosing increases of the atrium pressure.