Controlled release of enrofloxacin by vanillin-crosslinked chitosan-polyvinyl alcohol blends

In transdermal drug delivery applications uniform drug distribution and sustained release are of great importance to decrease the side effects. In this direction in the present research, vanillin crosslinked chitosan (CS) and polyvinyl alcohol (PVA) blend based matrix-type transdermal system was prepared by casting and drying of aqueous solutions for local delivery of enrofloxacin (ENR) drug. Subsequently, the properties including the morphology, chemical structure, thermal behavior, tensile strength, crosslinking degree, weight uniformity, thickness, swelling and drug release of the CS-PVA blend films before and after crosslinking were characterized. In vitro drug release profiles showed the sustained release of ENR by the incorporation of vanillin as a crosslinker into the CS-PVA polymer matrix. Furthermore, the release kinetic profiles revealed that the followed mechanism for all samples was Higuchi and the increase of vanillin concentration in the blend films resulted in the change of diffusion mechanism from anomalous transport to Fickian diffusion. Overall, the obtained results suggest that the investigated vanillin crosslinked CS-PVA matrix-type films are potential candidates for transdermal drug delivery system.

Mesenchymal stromal cells producing TNFα lack inhibitory effect against A375 experimental lung metastases

Cell-based anticancer therapy using mesenchymal stromal cells (MSCs) engineered to express therapeutic genes has a potential to target the cancer cells in vivo. Metastatic dissemination of melanoma remains a serious problem in the treatment. In our previous work we used MSCs overexpressing gene for tumor necrosis factor α (TNFα; MSCs/TNFα), and we achieved inhibition of melanoma xenograft growth when engineered MCSs/TNFα were coinjected with tumor cells subcutaneously. The TNFα as a pleiotropic cytokine induces apoptosis of tumor cells, creates "tumor resistant" microenvironment, enhances immune response and can have tumor destructive capacity in selected tumor types, especially in tumors of mesodermal origin.In this study we investigated the possibility of intravenously administered MCSs/TNFα to inhibit metastatic spread of A375 melanoma cells in the lungs. We confirmed elevated expression of TNFα transgene in the lung tissue 20 days after MCSs/TNFα intravenous infusion. We also documented that constitutive expression of TNFα transgene is able to neutralize the supportive effect of MSCs on melanoma cells growth. Metastatic spread of A375 melanoma cells in the lung was inhibited approximately to 50% after MCSs/TNFα i.v. administration in comparison to control group with parental MSCs supporting tumor growth. In conclusion, engineered MCSs/TNFα administered intravenously did not demonstrate significant antitumor effect against experimental melanoma lung metastases in this model settings.

Global and gene specific DNA methylation in breast cancer cells was not affected during epithelial-to-mesenchymal transition in vitro

Epithelial-to-mesenchymal transition (EMT) significantly affects the risk of metastasising in breast cancer. Plasticity and reversibility of EMT suggest that epigenetic mechanisms could be the key drivers of these processes, but little is known about the dynamics of EMT-related epigenetic alterations. We hypothesised that EMT, mediated by autocrine and paracrine signals, will be accompanied by changes in DNA methylation profiles. Therefore, conditioned medium from adipose tissue-derived mesenchymal stromal cells was used for induction of EMT in human breast cancer SK-BR-3 cell line. EMT-related morphological alterations and changes in gene expression of EMT-associated markers were assessed. To reverse EMT, 20 nm size gold nanoparticles (AuNPs) synthesized by the citrate reduction method were applied. Finally, DNA methylation of LINE-1 sequences and promoter methylation of TIMP3, ADAM23 and BRMS1 genes were quantitatively evaluated by pyrosequencing. Despite the presence of EMT-associated morphological and gene expression changes in tumour cells, EMT induced by adipose tissue-derived mesenchymal stromal cells had almost no effect on LINE-1 and gene-specific DNA methylation patterns of TIMP3, ADAM23 and BRMS1 genes. Although treatment for 24, 48 or 72 hours with 20 nm AuNPs at a concentration of 3 µg/ml slightly decreased gene expression of EMT-associated markers in SK-BR-3 cells, it did not alter global or gene-specific DNA methylation. Our results suggest that changes in DNA methylation are not detectable in vitro in early phases of EMT. Previously published positive findings could represent rather the sustained presence of potent EMT-inducing signals or the synergistic effect of various epigenetic mechanisms. Treatment with AuNPs slightly attenuated EMT, and their therapeutic potential needs to be further investigated.

Lymphoma transformation of tumor infiltrating lymphocytes observed in testicular patient‑derived xenograft models

Testicular germ cell tumors (TGCTs) are highly sensitive to cisplatin‑based chemotherapy. Nevertheless, there are metastatic tumors that do not completely respond to front‑line chemotherapy. For these tumors, surgical resection of residual masses is necessary to achieve long‑term disease control. Resected tissues represent valuable clinical material, which may be used for the engraftment into immunocompromised mice to produce patient‑derived xenografts (PDXs). They typically maintain similarities to the parental tumors and therefore serve as more realistic preclinical models. Moreover, a correlation between PDX treatment outcomes and clinical response to chemotherapy has been previously described. The aim of the present study was to establish and characterize TGCT patient‑derived xenografts. These originated from retroperitoneal lymph node metastases infiltrated with TGCTs following previous cisplatin‑based chemotherapy, in order to analyze novel treatment options for cisplatin‑resistant testicular tumors. We generated two testicular patient‑derived xenograft models in SCID beige male mice. Immunohistochemical analyses demonstrated that histological characteristics of the primary tumor were not retained, and transformation into lymphoma, and eventually plasmocytoma, was observed. A potential explanation for the lymphoma transformation observed in PDXs may include tumor‑infiltrating lymphocytes (TILs) in xenografted samples of patients, which are transformed following engraftment into immunodeficient recipient mice. Based on these data, we indicated that lymphomagenesis prevention and terminal differentiation represent new challenges in the establishment of PDX models derived from patients with germ cell tumors.

Genetically engineered mesenchymal stromal cells in cancer gene therapy

Based on our experimental data, we aimed to emphasise the perspectives of the use of mesenchymal stromal cells (MSC) in the cancer gene therapy. On the other hand, we would like to point out factors which should be taken into consideration at their clinical use. In this review we define MSC as unique targets for targeted therapy. We proved the efficacy of experimental therapeutic approach utilising enzymatic conversion of non-toxic prodrug into chemotherapeutic by engineered MSC, and we observed significant cytotoxic effect in many preclinical models including metastatic disease. Treatment was enabled by affinity of MSC to tumour tissue and subsequent delivery of therapeutic molecule into the tumour. We also observed decreased efficacy of cell-mediated gene therapy on chemoresistant tumour cells. Moreover MSC can exert a supportive effect on tumour cells as well as to decrease the efficacy of conventional treatment. Besides obvious unique benefits connected to the use of MSC we pointed also to possible risks associated with their clinical application (Ref. 24).

ALDH1A inhibition sensitizes colon cancer cells to chemotherapy

Background

Recent evidence in cancer research, developed the notion that malignant tumors consist of different subpopulations of cells, one of them, known as cancer stem cells, being attributed many important properties such as enhanced tumorigenicity, proliferation potential and profound multidrug resistance to chemotherapy. Several key stem cells markers were identified in colon cancer. In our study we focused on the aldehyde dehydrogenase type 1 (ALDH1) expression in colon cancer-derived cell lines HT-29/eGFP, HCT-116/eGFP and LS-180/eGFP, and its role in the chemoresistance and tumorigenic potential.

Methods

The effect of pharmacological inhibition of ALDH activity by diethylaminobenzaldehyde (DEAB) and also effect of molecular inhibition by specific siRNA was evaluated in vitro in cultures of human colorectal cell lines. The expression level of different isoenzymes of aldehyde dehydrogenase was determined using qPCR. Changes in cell biology were evaluated by expression analysis, western blot and apoptosis assay. The efficiency of cytotoxic treatment in the presence of different chemotherapeutic drugs was analyzed by fluorimetric assay. Tumorigenicity of cells with specific ALDH1A1 siRNA was tested in xenograft model in vivo.

Results

Treatment by DEAB partially sensitized the tested cell lines to chemotherapeutics. Subsequently the molecular inhibition of specific isoforms of ALDH by ALDH1A1 or ALDH1A3 siRNA led to sensitizing of cell lines HT-29/eGFP, HCT-116/eGFP to capecitabine and 5-FU. On the model of athymic mice we observed the effect of molecular inhibition of ALDH1A1 in HT-29/eGFP cells by siRNA. We observed inhibition of proliferation of subcutaneous xenografts in comparison to control cells.

Conclusion

This research, verifies the significance of the ALDH1A isoforms in multidrug resistance of human colorectal cancer cells and its potential as a cancer stem cell marker. This provides the basis for the development of new approaches regarding the treatment of patients with colorectal adenocarcinoma and potentially the treatment of other tumor malignancies.

Quality of life after bowel resection for Crohn´s disease - first results

INTRODUCTION

Crohn´s disease (CD) highly affects a patient´s quality of life. The aim of the study was to find out the impact of surgery on the quality of life (QoL) in CD patients and factors affecting their postoperative QoL.

METHODS

90 patients with CD who underwent surgery (bowel resection) filled out an EORTC QLQ-CR29 questionnaire preoperatively and again after the surgical procedure.

RESULTS

77% of the patients experienced a positive change (p<0.001), 22% negative and 11% no change.

CONCLUSION

In this cohort, we proved that surgical treatment improves the overall QoL in patients with CD. To determine factors which affect postoperative QoL, more patients need to be enrolled in future studies.Key words: Crohn´s disease - quality of life - surgery - bowel resection - Czech cohort.

Tumor microenvironment and the role of mesenchymal stromal cells

Solid tumors are generally composed of two major components: heterogeneous malignant cells and non-malignant stromal part. The latter comprises several types of non-malignant cells of mesenchymal, endothelial and immune origin and together with the extracellular matrix significantly affects the biological properties of the tumor. This minireview is focused on recent advances in the understanding the role of tumor stromal component and its particular cell types in the tumor behavior. It summarizes the impact of mesenchymal stromal cells and the ways of their potential contribution to the tumor biology. As their role in the tumor development and the effects on the tumor cells remain controversial, we review the recent experimental evidence regarding the crucial molecular factors which determine their role in the tumors.

KEYWORDS

tumor microenvironment, human mesenchymal stromal cells, paracrine interaction, malignant cells.

Interaction of human adipose tissue-derived mesenchymal stromal cells with breast cancer cells

Human adipose tissue was shown to be a very attractive source of mesenchymal stromal cells that have a wide scale of potential applications in reconstructive plastic surgery and regenerative medicine. However, these cells were described to have profound effects on biological behaviour of tumour cells. The aim of this study was to analyze the influence of adipose tissue-derived human mesenchymal stromal cells (AT-MSC) on the proliferation of breast cancer cells. We have tested proliferation of three different human breast cancer cell lines under the influence of AT-MSC derived soluble factors as well as in the direct cocultures. These data were supplemented with the expression analysis of cytokines and their cognate receptors on the target cells. We have observed stimulation of proliferation in breast cancer cells MDA-MB-361, T47D and EGFP-MCF7. AT-MSC were found to secrete wide scale of cytokines, chemokines and growth factors, thus we concluded that this pro-proliferative effect was a result of their synergistic action. These data bring out a need to evaluate whether primary breast tumour derived human cells would respond to these type of stimuli in a similar manner in order to exclude any potential clinical risk related to the application of human mesenchymal stromal cells under the context of patient with history of breast cancer malignancy.

FcγRIIIA receptor genotype does not influence an outcome in patients with follicular lymphoma treated with risk-adapted immunochemotherapy

Antibody (rituximab) dependent cellular cytotoxicity is a key mechanism in killing CD20+ lymphoma cells. FcγRIIIA-158 V/F gene polymorphism results in expression of 3 variants of the FcγRIIIA receptor (FcγRIIIA) on cytotoxic lymphocytes with different receptor affinity. We studied 102 patients with newly diagnosed FL to assess whether the FcγRIIIA genotype influences outcome in patients treated with risk-adapted immunochemotherapy. The median age was 52 years (31-84); 90% of the patients had advanced (III/IV) clinical stages. The Follicular Lymphoma International Prognostic Index (FLIPI) scores were as follows: low 18.9%, intermediate 33.7% and high 47.4%. The front-line treatment was stratified according to the commonly used risk factors (FLIPI, beta-2-microglobuline and serum-Tyrosine-Kinase levels, bulky disease) into 3 treatment groups: (1) patients with FLIPI 0-1 treated with (R)-CHOP (51%), (2) patients under 60 (65) years of age with intermediate-risk disease (FLIPI 2) indicated for an intensive protocol (ProMACE-CytaBOM or sequential chemotherapy) (21%), and (3) patients under 60 (65) years with high-risk disease (FLIPI ≥3) treated with intensive chemotherapy plus autologous stem cell transplantation (28%). Rituximab was added to front-line chemotherapy in 59% of the patients. Generally, complete remission (CR) or unconfirmed CR was achieved in 85% of the patients, 11% had partial remission and 4% stable disease. Molecular CR (CRm) was achieved in 67.4% of 86 evaluable patients. Overall survival (OS) at 5 years reached 84% (95% CI 0.74-0.93); event-free survival (EFS) at 5 years was 58% (95% CI 0.45-0.71). The frequencies of FcγRIIIA-158 gene polymorphisms V/V, V/F and F/F were 8%, 50% and 42%, respectively. The FLIPI score distribution was not different in F/F patients as compared to V/F+V/V carriers (chi-square, P=0.7). The treatment modalities (treatment arm or rituximab administration) had the same distribution in V/V+V/F vs F/F patients (chi-square, P=0.16 and P=0.62, respectively). The CRm rates were similar in both subgroups of V/V+V/F vs F/F patients (chi-square, P=0.92). Survival curves for OS and EFS were not significantly different when comparing the subgroups of V/V+V/F vs F/F patients (P=0.28 and P=0.57, respectively). We found no difference in the quality of treatment response or survival after front-line immunochemotherapy between FcγRIIIA subgroups. FcγRIIIA polymorphism have no influence on the outcome of patients treated with risk-adapted chemotherapy with or without rituximab.

Genotoxic damage of human adipose-tissue derived mesenchymal stem cells triggers their terminal differentiation

Human adipose tissue-derived mesenchymal (stromal) stem cells (AT-MSCs) and genetically modified to express cytosine deaminase:uracil phosphoribosyltransferase (CDy-AT-MSCs) were treated with hydrogen peroxide in order to induce DNA damage and subsequently evaluate their genetic stability by single cell gel electrophoresis. Both cells types (parental and transgene modified) did not differ in the sensitivity to DNA breaks induction. Potential tumorigenicity of AT-MSCs and CDy-AT-MSCs was tested by subcutaneous inoculation of cell suspension into flank of immunocompromised mice. Dose of 15x10(6) cells was not found to be tumorigenic in given experimental setup. AT-MSCs, CDy-AT-MSCs and MSCs isolated from human lipoma were treated with chemical carcinogen 4-nitroquinoline-1-oxide (4NQO) in attempts to transform them. Surviving cells after genotoxic stress were not transformed but underwent replicative senescence. Irreparable DNA damage caused triggered adipogenic terminal differentiation, rather than apoptosis induction in all kinds of cells tested.

Endorectal sonography in rectal cancer staging and indication for local surgery

BACKGROUND/AIMS

Radical surgery still plays a decisive role in the therapy of rectal cancer. Besides classical abdominal operations, an alternative is transanal endoscopic resection of rectal tumor at T1 and T2 stages. Indication for local resection of malignant rectal tumor requires an accurate preoperative staging.

METHODOLOGY

The paper evaluates the accuracy of 3D endorectal sonography in rectal cancer staging. In the group of 78 patients the staging of preoperative 3D endorectal sonography was compared with a final histopathologic of the operative sample.

RESULTS

The results obtained indicate that the preoperative staging of malignant rectal tumor using 3D endorectal sonography represents 100% only in the pT1 stage. In the pT2 stage, the accuracy of 3D endorectal sonography is 72%, in pT3 and pT4 represents 92%.

CONCLUSIONS

On the basis of our experience, complicated interpretation of findings obtained by 3D endorectal sonography occurs at limits of T2-T3 and T3-T4. In these localizations the peripheral reactive fibrous and inflammatory sections in the vicinity of tumor tissue often involve even the next layer of rectal wall and leads to overevaluation of invasion depth at endorectal sonography of rectal cancer.

Bovine leukemia virus structural gene vectors are immunogenic and lack pathogenicity in a rabbit model

Infection with a replication-competent bovine leukemia virus structural gene vector (BLV SGV) is an innovative vaccination approach to prevent disease by complex retroviruses. Previously we developed BLV SGV that constitutively expresses BLV gag, pol, and env and related cis-acting sequences but lacks tax, rex, RIII, and GIV and most of the BLV long terminal repeat sequences, including the cis-acting Tax and Rex response elements. The novel SGV virus is replication competent and replicates a selectable vector to a titer similar to that of the parental BLV in cell culture. The overall goal of this study was to test the hypothesis that infection with BLV SGV is nonpathogenic in rabbits. BLV infection of rabbits by inoculation of cell-free BLV or cell-associated BLV typically causes an immunodeficiency-like syndrome and death by 1 year postinfection. We sought to evaluate whether in vivo transfection of BLV provirus recapitulates pathogenic BLV infection and to compare BLV and BLV SGV with respect to infection, immunogenicity, and clinical outcome. Three groups of rabbits were subjected to in vivo transfection with BLV, BLV SGV, or negative control DNA. The results of our 20-month study indicate that in vivo transfection of rabbits with BLV recapitulates the fatal BLV infection produced by cell-free or cell-associated BLV. The BLV-infected rabbits exhibited sudden onset of clinical decline and immunodeficiency-like symptoms that culminated in death. BLV and BLV SGV infected peripheral blood mononuclear cells and induced similar levels of seroconversion to BLV structural proteins. However, BLV SGV exhibited a reduced proviral load and did not trigger the immunodeficiency-like syndrome. These results are consistent with the hypothesis that BLV SGV is infectious and immunogenic and lacks BLV pathogenicity in rabbits, and they support the use of this modified proviral vector delivery system for vaccines against complex retroviruses like BLV.

DNA/genetic vaccination (minireview)

An important new approach to vaccination is plasmid DNA injection in vivo that can elicit an immune response against protein(s) encoded. Antigen that is expressed from the in vivo transfected cells induces both humoral and cellular immune response. DNA immunization is generally applicable for a wide range of proteins. It can provide an organism with immunity against viruses, bacteria, parasites, and tumors. DNA vaccines can overcome the disadvantages of vaccines presently used as well as provide various new vaccines that are currently not available. This minireview provides an overview of evaluated DNA vaccine candidates against infectious agents and certain cancers.

In vivo study of genetically simplified bovine leukemia virus derivatives that lack tax and rex

Genetically simplified derivatives of complex retroviruses that replicate in animal models are useful tools to study the role of the complex regulatory genes in virus infection and pathogenesis and were proposed as a novel approach toward the development of vaccines against complex retroviruses. Previously we developed genetically simple derivatives of bovine leukemia virus (BLV) that can replicate in tissue culture independently of the BLV regulatory proteins, Tax and Rex, and the RIII and GIV open reading frames (K. Boris-Lawrie and H. M. Temin, J. Virol. 69:1920-1924, 1995). These derivatives are encoded on novel, hybrid retrovirus genomes that contain transcriptional control sequences of a simple retrovirus and gag-pol or env genes of the complex BLV. The first-generation simple BLV derivatives replicate as complementary viruses (coviruses) by using separate gag-pol or env genomes, and therefore virus spread is limited to cells that are infected with both covirus genomes. Here we describe a second-generation simple BLV derivative that is encoded on a single hybrid genome. We show the virus to be replication competent by successive passage on D17 target cells and by analysis of viral RNA and proteins in the infected cells. Furthermore, we evaluate the immunogenicity and infectivity of the simple BLV derivatives in a BLV animal model. Small groups of rats were injected either with virus-producing cells or with proviral DNA. Western immunoblot analysis revealed that antibodies against the major viral antigenic determinants are induced in response to either method of introduction and that seroconversion is sustained in most of the rats for at least 6 months (the duration of the study). The magnitudes of the antiviral responses were similar in rats infected with the first-generation simple BLV coviruses, the second-generation replication-competent derivative, or wild-type BLV. Wild-type BLV typically infects peripheral blood mononuclear cells (PBMC), and the simple BLV derivatives were also found to infect PBMC as demonstrated by PCR amplification of proviral sequences and reverse transcriptase PCR amplification of viral RNA in treated rats. These results establish that simple BLV derivatives lacking tax and rex are infectious and immunogenic in rats. These viruses will be useful tools in comparative studies with BLV to evaluate the role of tax and rex in maintenance of virus load and in disease outcome.

Fulminant hepatitis caused by a hepatitis B virus infection in the patients with haematologic malignancies. Report of 5 cases

We describe 5 cases of fulminant hepatitis caused by the HBV infection in patients with haematological diseases, mostly malignancies (ALL, lymphoma, aplastic anemia, AML) following intensive chemotherapy. Infection was confirmed by serological examination (HBsAg positivity) and by electron microscopy (viral particles). After termination of chemotherapy fulminant hepatitis developed with hepatic failure and very high levels of AST and ALT. Autopsy revealed massive necrosis without signs of regeneration. We suggest that immunosuppressive therapy increases the risk of severe infection of hepatocytes with HBV and subsequent withdrawal of chemotherapy causes "immunological rebound" leading to massive necrosis.