The Significance of Microenvironmental and Circulating Lactate in Breast Cancer

Lactate represents the main product of pyruvate reduction catalyzed by the lactic dehydrogenase family of enzymes. Cancer cells utilize great quantities of glucose, shifting toward a glycolytic metabolism. With the contribution of tumor stromal cells and under hypoxic conditions, this leads toward the acidification of the extracellular matrix. The ability to shift between different metabolic pathways is a characteristic of breast cancer cells and is associated with an aggressive phenotype. Furthermore, the preliminary scientific evidence concerning the levels of circulating lactate in breast cancer points toward a correlation between hyperlactacidemia and poor prognosis, even though no clear linkage has been demonstrated. Overall, lactate may represent a promising metabolic target that needs to be investigated in breast cancer.

The lncRNA epigenetics: The significance of m6A and m5C lncRNA modifications in cancer

Most of our transcribed RNAs are represented by non-coding sequences. Long non-coding RNAs (lncRNAs) are transcripts with no or very limited protein coding ability and a length >200nt. They can be epigenetically modified. N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), 7-methylguanosine (m7G) and 2’-O-methylation (Nm) are some of the lncRNAs epigenetic modifications. The epigenetic modifications of RNA are controlled by three classes of enzymes, each playing a role in a specific phase of the modification. These enzymes are defined as “writers”, “readers” and “erasers”. m6A and m5C are the most studied epigenetic modifications in RNA. These modifications alter the structure and properties, thus modulating the functions and interactions of lncRNAs. The aberrant expression of several lncRNAs is linked to the development of a variety of cancers and the epigenetic signatures of m6A- or m5C-related lncRNAs are increasingly recognized as potential biomarkers of prognosis, predictors of disease stage and overall survival. In the present manuscript, the most up to date literature is reviewed with the focus on m6A and m5C modifications of lncRNAs and their significance in cancer.

Spartin: At the crossroad between ubiquitination and metabolism in cancer

SPART is a gene coding for a multifunctional protein called spartin, localized in various organelles of human cells. Mutations in the coding region are responsible for a hereditary form of spastic paraplegia called Troyer syndrome while the epigenetic silencing has been demonstrated for some types of tumors. The main functions of this gene are associated to endosomic trafficking and receptor degradation, microtubule interaction, cytokinesis, fatty acids and oxidative metabolism. Spartin has been shown to be a target regulated by STAT3 and localizes also at the level of the mitochondrial outer membrane, where it forms part of a complex maintaining the integrity of the membrane potential. The most recent evidences report a downregulation of spartin in tumor tissues when compared to adjacent normal samples. This intriguing evidence supports further research aimed at clarifying the role of this protein in cancer development and metabolism.

Abstract 3759: Recurrent methylation heterogeneity and reduced expression of SPG20 is a common characteristic of different tumors

Background: The Spastic Paraplegia-20 (SPG20, also known as SPART), is a gene that encodes spartin protein. When SPG20 is mutated, spartin expression is downregulated and leads to a rare autosomal recessive disorder called Troyer Syndrome. We recently demonstrated that this gene is epigenetically silenced and downregulated in Diffuse Large B Cell Lymphoma (DLBCL) cell lines. In recent years, other authors demonstrated independently the epigenetic regulation of SPG20 in hepatocellular, gastric and colorectal cancers. In order to assess whether the differential methylation of SPG20 is a common characteristic of tumors of different histological origin, we analysed the methylation of 9 probes upstream of the transcription starting site (TSS) and the gene expression of SPG20 in tumor samples affecting 6 different anatomical sites.

Methods: Illumina Infinium Human Methylation 450 BeadChip and RNAseq data extrapolated from The Cancer Genome Atlas (TCGA) database were used to evaluate the methylation levels and expression of SPG20. Bladder, Colon, Kidney, Liver, Lung and Prostate datasets were selected. At least 30 independent tumor and at least 5 normal tissue samples for each tumor site were analysed. The tumor and normal tissues were paired in each specific cohort. Transcriptome profiling was analysed only in datasets where both tumor and normal counterparts were available. Statistical analysis was performed by two-way ANOVA with a Sidak’s post hoc test for methylation analysis and multiple t-test with Holm-Sidak’s post hoc test for expression analysis.

Results: SPG20 β-values ranging from 0.19 to 0.96 among the different tumor samples were observed in the promoter region covered by the 9 probes that we previously identified (Illumina 450k platform). In the normal group, the β-values were higher than 0.63. Statistically significant differences between the tumor and normal counterpart were observed in colon, liver and prostate and mainly in the probes closest the TSS. The heterogeneity in the methylation status of SPG20 was a common characteristic among the different tumor groups. The variability range of β-values between tumor and normal groups was significantly different with a p value <0.05. Differential expression was observed between tumor and normal counterpart in almost all sites. SPG20 was more expressed in normal than in tumor tissues and the differences were significant in bladder, lung and colon.

Conclusion: Our analysis unveils that the methylation heterogeneity of SPG20 is a common hallmark in all the tumor samples, while the normal counterpart results homogenously distributed. In tumor samples there is an inverse correlation between SPG20 promoter methylation heterogeneity and gene expression. SPG20 is down-regulated in almost all the tumors of different histological origins. SPG20 could have a relavant but still undefined role in cancer as a tumor-suppressor gene.

Citation Format: Vincenza Ylenia Cusenza, Raffaele Frazzi. Recurrent methylation heterogeneity and reduced expression of SPG20 is a common characteristic of different tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3759.

KLF4, DAPK1 and SPG20 promoter methylation is not affected by DNMT1 silencing and hypomethylating drugs in lymphoma cells

Promoter methylation represents one of the major epigenetic mechanisms responsible for the regulation of gene expression. Hypomethylating drugs are currently approved for the treatment of myelodysplastic syndromes and acute myeloid leukemia, and some studies have recently been carried out on diffuse large B cell lymphoma (DLBCL). DLBCL is a type of Non-Hodgkin lymphoma. The aim of the present study was to assess the role of DNA methyltransferase (DNMT)1 in mediating the epigenetic regulation of some key targets previously emerged as hypermethylated in Non-Hodgkin lymphoma. Reverse transcription-quantitative PCR, genome-wide arrays and methylation-specific PCR were used to determine the level of methylation of specific targets. Gene silencing, gene expression and immunoblotting were used to investigate the role of DNMT1 and DNMT3a in lymphoma cells. The present study showed that lymphoma cell lines displayed a completely different methylation profile on selected targets compared with primary B lymphocytes and peripheral blood mononuclear cells. 5′-aza-cytidine (5AZA) and 5′-aza-2-deoxycitidine (decitabine) exerted their activity through, at least in part, mechanisms independent of DNMT1 downregulation. Despite a global hypomethylating effect of 5AZA and decitabine, DNMT1 was not found to be necessary to maintain the hypermethylation of Krüppel-like factor 4 (KLF4), death associated protein 1 (DAPK1) and spastic paraplegia 20 (SPG20). SPG20 was found to be a completely methylated target in all the tested cell lines, but not in peripheral blood mononuclear cells, suggesting its association with malignancy. The highest methylation was clustered upstream of the transcription starting site in a panel of 28 DLBCL cell lines and the results were unaffected by the silencing of DNMT1 expression. These data demonstrated the epigenetic regulation of SPG20 in lymphoid cells and identified a number of novel markers associated with lymphomas that deserve further investigation.

Copy Number Variation and Rearrangements Assessment in Cancer: Comparison of Droplet Digital PCR with the Current Approaches

The cytogenetic and molecular assessment of deletions, amplifications and rearrangements are key aspects in the diagnosis and therapy of cancer. Not only the initial evaluation and classification of the disease, but also the follow-up of the tumor rely on these laboratory approaches. The therapeutic choice can be guided by the results of the laboratory testing. Genetic deletions and/or amplifications directly affect the susceptibility or the resistance to specific therapies. In an era of personalized medicine, the correct and reliable molecular characterization of the disease, also during the therapeutic path, acquires a pivotal role. Molecular assays like multiplex ligation-dependent probe amplification and droplet digital PCR represent exceptional tools for a sensitive and reliable detection of genetic alterations and deserve a role in molecular oncology. In this manuscript we provide a technical comparison of these two approaches with the golden standard represented by fluorescence in situ hybridization. We also describe some relevant targets currently evaluated with these techniques in solid and hematologic tumors.

BIRC3 and BIRC5: multi-faceted inhibitors in cancer

BACKGROUND

The evasion from apoptosis is a common strategy adopted by most tumors, and inhibitors of apoptosis proteins (IAPs) are among the most studied molecular and therapeutic targets. BIRC3 (cellular IAP2) and BIRC5 (survivin) are two of the eight members of the human IAPs family. This family is characterized by the presence of the baculoviral IAP repeat (BIR) domains, involved in protein-protein interactions. In addition to the BIR domains, IAPs also contain other important domains like the C-terminal ubiquitin-conjugating (UBC) domain, the caspase recruitment (CARD) domain and the C-terminal Ring zinc-finger (RING) domain.

MAIN BODY

BIRC3 and BIRC5 have been characterized in some solid and hematological tumors and are therapeutic targets for the family of drugs called "Smac mimetics". Many evidences point to the pro-survival and antiapoptotic role of BIRC3 in cancer cells, however, not all the data are consistent and the resulting picture is heterogeneous. For instance, BIRC3 genetic inactivation due to deletions or point mutations is consistently associated to shorter progression free survival and poor prognosis in chronic lymphocytic leukemia patients. BIRC3 inactivation has also been associated to chemoimmunotherapy resistance. On the contrary, the progression from low grade gliomas to high grade gliomas is accompanied by BIRC3 expression increase, which bears relevant prognostic consequences. Due to the relationship between BIRC3, MAP3K14 and the non-canonical NF-kB pathway, BIRC3 inactivation bears consequences also on the tumor cells relying on NF-kB pathway to survive. BIRC5, on the contrary, is commonly considered an anti-apoptotic molecule, promoting cell division and tumor progression and it is widely regarded as potential therapeutic target.

CONCLUSIONS

The present manuscript collects and reviews the most recent literature concerning the role played by BIRC3 and BIRC5 in cancer cells, providing useful information for the choice of the best therapeutic targets.

Abstract 163: DNA methyltransferase modulation in lymphoma cells involves functional redundancy and maintains hypermethylation of selected regions

Background. DNA methyltransferases (DNMTs) are key enzymes necessary to the cells in order to establish and maintain methylation marks across the genome during both embrional development and adult cell divisions.

DNMT1 is the main target of hypomethylating drugs 5-azacytidine (5-AZA) and 5-aza-2'-deoxycytidine (decitabine). These drugs have been used for a long time even though some mechanisms of action are yet unknown. We previously demonstrated that 5AZA and decitabine markedly down-regulate DNMT1 in a dose-dependent fashion, activate PARP and casp-3/7. However, 5AZA does not affect the methylation of selected targets, namely KLF4, DAPK1 and SPG20, who had been shown to play a role in lymphoma malignancy. We also observed that human PBMCs display an unmethylated profile that is opposite to the lymphoma cells.

Experimental procedures. Toledo (Germinal center-derived) and NU-DUL-1 (Activated B-cell like) diffuse large-B cell lymphoma (DLBCL) cell lines. Epitect methyl II methylation qPCR. Immunoblottings. Gene silencing through siRNAs. Illumina Infinium 450K methylation arrays. Bioinformatics analysis for CpG doublets identification.

Results. In order to dissect the molecular contribution of the main DNMTs during methylation maintenance, we individually silenced DNMT1 and DNMT3a in DLBCL cell lines. We show that neither DNMT1-, DNMT3a- nor double-silencing significantly affects the promoter methylation of KLF4, DAPK1 and SPG20. Genome-wide methylation analysis on a panel of 45 B-cell lymphoma cell lines reveals that the SPG20 locus presents hypermethylated CpG doublets upstream of the transcription starting site (open sea regions) while is mainly hypomethylated within the first exon. An intronic CpG island maps within SPG20 locus and presents heterogeneous beta-values among CpG sites.

After 7 days from transfection, surprisingly, DNMT1, 3a and 3b gene expressions increase above the controls in Toledo cells. Furthermore, DNMT3a-silencing leads to DNMT1 protein upregulation in Toledo and NU-DUL-1 cells, suggesting a feedback regulatory mechanism. These data support a mechanism through which the methylation maintaining capacity of the cells is preserved even under pharmacological pressure.

Conclusions. DNMT1- and DNMT3a-silencing exert a different effect on DNMTs regulation in lymphoma cells and evidences a functional redundancy among family members. Our data overall suggest that DNMT3a exerts suppressive effect on DNMT1, possibly by participating to the formation of a multi-factorial repressor complex.

Citation Format: Raffaele Frazzi, Vincenza Ylenia Cusenza, Luciano Cascione, Andrea Rinaldi, Francesco Bertoni, Mariaelena Pistoni, Francesco Merli. DNA methyltransferase modulation in lymphoma cells involves functional redundancy and maintains hypermethylation of selected regions [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 163.

Abstract 5198: 5AZA and decitabine exhibit different molecular effects on non-Hodgkin lymphoma cells: Involvement of DNMT3a

Introductory sentence. Demethylating drugs represent a powerful tool for epigenetic modulation of chromatin structure in cancer cells. 5-azacytidine (5-AZA) and 5-aza-2’-deoxycytidine (decitabine) are promising therapeutic solutions also in mature B-cell neoplasms, although the molecular mechanisms of action have yet to be elucidated. Here we describe their effects on non-Hodgkin lymphoma cells and demonstrate how hypomethylation is not homogeneous across the genome. Experimental procedures. Toledo (GC-derived) and NU-DUL-1 (ABC-like) diffuse large-B cell lymphoma (DLBCL; non-Hodgkin) cell lines. Peripheral blood mononuclear cells (PBMCs) isolation. Epitect methyl II methylation qPCR and global chromatin methylation quantitative assays. Immunoblottings. Proliferation assays. CpG islands bioinformatics analysis. Comet assay and phosphorylation of gamma-H2AX histone assay. Gene silencing through siRNAs. New data. A panel of 9 CpG islands within a set of genes that we previously identified has been investigated as a potential target for hypomethylating activity of 5AZA and decitabine. KLF4, DAPK1 and SPG20 promoters (located on chr. n°9 the first two and n°3 the latter) are not affected by a single dose of 5AZA after 48h or 7 days of incubation (the CpG islands within these promoters are fully unmethylated in healthy PBMCs). However, global chromatin demethylation is clearly visible either after 48h or 7 days in both cell lines. By comparison, decitabine demethylating effects return to the initial values after 7 days. MZB1 promoter results demethylated by both treatments, while MGMT is demethylated only in NU-DUL-1 by decitabine but not 5AZA. These data suggest that hypomethylating agents act selectively on discrete regions of the genome. 5AZA and decitabine markedly down-regulate DNMT1 in a dose-dependent fashion and activate PARP. Despite DNMT1 downregulation, KLF4, DAPK1 and SPG20 promoters result unaffected. DNMT1 silencing in our cells do not cause any change in the promoter methylation of the selected targets. The de novo methyltransferase DNMT3a is expressed only by NU-DUL-1 and its silencing leads to a partial MZB1 demethylation and to the significant decrease in global chromatin methylation whereas DNMT1 silencing does not. In order to assess an involvement of the genotoxic damage, Comet assays were performed up to 24 hours of incubation with the drugs. We demonstrate that 5AZA does not induce any significant genotoxic damage while decitabine causes a tail formation starting at 6h after drug administration. Conclusions. Our data show that 5AZA and decitabine exhibit different mechanisms of action on lymphoma cells. Different DLBCL-derived cell lines display different changes when exposed to single doses of hypomethylating drugs, underlying the fact that cell of origin may play a role during the response. DNMT3a contributes to chromatin methylation in lymphoma cells.

Citation Format: Raffaele Frazzi, Tonia De Simone, Olga Serra, Annamaria Buschini, Laura Canovi, Tiziana De Luca, Francesco Merli. 5AZA and decitabine exhibit different molecular effects on non-Hodgkin lymphoma cells: Involvement of DNMT3a [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5198.

Abstract 5334: Spg20 (Spartin) promoter methylation identifies tumor B lymphocytes

Introductory sentence. The layer of regulation represented by gene promoter methylation is being investigated in Non-Hodgkin lymphoma (NHL) cell lines, primary B lymphocytes and peripheral blood mononuclear cells (PBMCs). The aim is to assess whether the panel of differentially methylated genes we previously identified is able to distinguish normal B lymphocytes from lymphoma cells.

Experimental procedures. Quantitative, gene-specific methylation assays. Immunosorting of human B lymphocytes. Proliferation assays. 5-azacytidine treatment. NHL-derived cell lines.

New data. Here we show that NHL-derived cell lines display a characteristic profile of promoter methylation on specific tumor suppressors and target genes. A panel of 9 target promoters was selected previously and assessed on a series of healthy and tumor primary B lymphocytes. 4 out of 5 NHL-cell lines show a highly methylated profile on KLF4, DAPK1 and SPG20, at variance with normal B lymphocytes (lymph-node derived) and PBMCs where these targets are completely unmethylated. Interestingly, PBMCs from healthy donors display the same methylation pattern as the one shown by B lymphocytes immunologically sorted from follicular hyperplasias. Spartin (SPG20) emerges here as a differentially methylated gene associated to lymphocyte malignancy, at variance with other tumor suppressors in our panel that show variability among different cell lines. SPG20 is completely or highly methylated in all the tested NHL-cell lines. According to this observation, SPG20 results not methylated in PBMCs as well as sorted non-tumor B lymphocytes. On the contrary, the methylation status of three different BCL6 CpG islands (assessed with the same technique) may vary among different cell lines. In order to investigate what's the functional role of these specific promoters methylation, we treated Toledo and NU-DUL-1 cell lines with the demethylating agent 5-azacytidine (5AZA). We observe that the dose-dependent inhibition of proliferation upon 5AZA is accompanied by a small but reproducible decrease in SPG20 and MZB1 promoter methylation. Experiments aimed at assessing any involvement of DNA methyltransferases DNMT1 and DNMT3a are currently ongoing.

Conclusions. Our data show a consistent methylation profile of 9 gene promoters on 5 different NHL-derived cell lines. Spartin emerges as a completely methylated promoter in the tested tumor cells. PBMCs show a consistent unmethylated profile of Spartin and of all the target genes. The epigenetic regulation of these genes in B-derived lymphomas warrants further investigation.

Citation Format: Raffaele Frazzi, Tonia De Simone, Mariaelena Pistoni, Francesco Merli. Spg20 (Spartin) promoter methylation identifies tumor B lymphocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5334.

Use of FTA® classic cards for epigenetic analysis of sperm DNA

FTA® technologies provide the most reliable method for DNA extraction. Although FTA technologies have been widely used for genetic analysis, there is no literature on their use for epigenetic analysis yet. We present for the first time, a simple method for quantitative methylation assessment based on sperm cells stored on Whatman FTA classic cards. Specifically, elution of seminal DNA from FTA classic cards was successfully tested with an elution buffer and an incubation step in a thermocycler. The eluted DNA was bisulfite converted, amplified by PCR, and a region of interest was pyrosequenced.

SIRT1 in Secretory Organ Cancer

Mammalian silent information regulator 1 (SIRT1) is reported to play a role in cancers of the secretory organs, including thyroid, pancreatic endocrine, and ovarian tumors [1, 2, 3, 4]. A recent meta-analysis conducted on 37 selected studies of human cancers analyzed the correlations of overall survival (OS), disease-free survival (DFS) and relapse-free survival (RFS) with SIRT1 expression [5]. This study reported that SIRT1 overexpression was associated with a worse OS in liver and lung cancers, while it was not correlated with OS in breast cancer, colorectal cancer, or gastric carcinoma. Collectively, the meta-analysis revealed that an unfavorable OS was associated with SIRT1 expression for solid malignancies. Given the growing importance of this class of lysine/histone deacetylases in human endocrine malignancies, a rational and focused literature assessment is desirable in light of future clinical translations.

Abstract 5: The effects of SIRT1 inhibitors nicotinamide and Ex-527 on lymphoma cells

SIRT1 is a well-known lysine-deacetylase, having both histone and non-histone proteins as molecular targets. SIRT1 may function as a tumor promoter as well as a tumor suppressor in a context-dependent manner. We previously demonstrated that the treatment with resveratrol at concentrations able to induce apoptosis leads to SIRT1 down-regulation in lymphoma cells. Here we look for SIRT1 inhibition in order to investigate the effects on proliferation potential, apoptosis induction and targets modulation at a molecular level. The aim is to study whether SIRT1 inhibition affects cell cycle and proliferation capability of lymphoma cells. Experimental procedures. Diffuse large-B cell lymphoma derived cell line Toledo; human lymphoblastoid cell line GGB #7; SIRT1 inhibitors: nicotinamide (NAM) and Ex-527; cell cycle analysis; caspase-3 activity fluorimetric assay; genotoxicity assay gamma-H2AX; fluorescence-activated cell sorting intracellular staining for acetylated-H4K16 histone. New data. We found that the calculated IC50s for SIRT1 inhibition is 50mM for NAM and 343μM for Ex-527. The treatment with either NAM or Ex-527 leads to cell cycle arrest in both Toledo and GGB#7 cells, although in a different fashion. Namely, NAM causes an S-phase accumulation of Toledo while it leads GGB #7 to G0/G1 phase arrest with a concomitant decrease in S-phase already after 10mM. In both cell lines NAM 50mM induces apoptosis as demonstrated by caspase-3 activation and sub-G1 peak appearance in the cell cycle profiles. Ex-527 causes an accumulation in the S phase of Toledo cells and a decrease of G2/M in GGB#7 cells. No induction of apoptosis at the IC50 concentration was observed in both cell lines. Genotoxicity of the above mentioned treatments was investigated through the quantitation of gamma-H2AX histone released by treated cells. No genotoxic effects have been observed upon the treatments with these two inhibitors even at the concentration where NAM induces apoptosis. In order to correlate the observed changes with SIRT1 inhibition, we studied the acetylated H4K16 histone, a direct target of SIRT1 deacetylation. Our preliminary data indicate that NAM treatment increases the percentage of acetylated H4K16. Conclusions. Lymphoma and lymphoblastoid cells are affected by SIRT1 inhibition. NAM and Ex-527 cause cell cycle arrest and growth inhibition. Only NAM 50mM induces apoptosis without genotoxic effects. Overall, our data suggest the direct involvement of SIRT1 during the observed cell cycle arrest and growth inhibition mediated by these inhibitors.

Citation Format: Manuela Guardi, Mariaelena Pistoni, Raffaele Frazzi. The effects of SIRT1 inhibitors nicotinamide and Ex-527 on lymphoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5. doi:10.1158/1538-7445.AM2017-5

Methylation changes of SIRT1, KLF4, DAPK1 and SPG20 in B-lymphocytes derived from follicular and diffuse large B-cell lymphoma

Diffuse large-B cell lymphomas (DLBCL) and follicular lymphomas (FL) are the most represented subtypes among mature B-cell neoplasms and originate from malignant B lymphocytes. Methylation represents one of the major epigenetic mechanisms of gene regulation. Silent information regulator 1 (SIRT1) is a class III lysine-deacetylase playing several functions and considered to be a context-dependent tumor promoter. We present the quantitative methylation, gene expression and tissue distribution of SIRT1 and some key mediators related to lymphoma pathogenesis in B lymphocytes purified from biopsies of follicular hyperplasias, FL and DLBCL. SIRT1 mRNA levels are higher in FL than follicular hyperplasias and DLBCL. B cell lymphoma 6 (BCL6) positively correlates with SIRT1. SIRT1 promoter shows a methylation decrease in the order: follicular hyperplasia - FL - DLBCL. Kruppel-like factor 4 (KLF4), Death-associated protein kinase 1 (DAPK1) and Spastic Paraplegia 20 (SPG20) methylation increase significantly in FL and DLBCL compared to follicular hyperplasias. Gene expression of DAPK1 and SPG20 inversely correlates with their degree of methylation. Our findings evidence a positive correlation between SIRT1 and BCL6 expression increase in FL. SIRT1 methylation decreases in FL and DLBCL accordingly and this parallels the increase of KLF4, DAPK1 and SPG20 methylation.

Integrative systems medicine approaches to identify molecular targets in lymphoid malignancies

Although survival rates for lymphoproliferative disorders are steadily increasing both in the US and in Europe, there is need for optimizing front-line therapies and developing more effective salvage strategies. Recent advances in molecular genetics have highlighted the biological diversity of lymphoproliferative disorders. In particular, integrative approaches including whole genome sequencing, whole exome sequencing, and transcriptome or RNA sequencing have been instrumental to the identification of molecular targets for treatment. Herein, we will discuss how genomic, epigenomic and proteomic approaches in lymphoproliferative disorders have supported the discovery of molecular lesions and their therapeutic targeting in the clinic.

Abstract 4451: Different patterns of SIRT1, KLF4, DAPK1 and SPG20 methylation in B lymphocytes correlate with the clinical parameters of non-Hodgkin lymphoma subtypes

Background. DNA methylation is one of the best studied epigenetic modifications and one major constituent of the epigenome of a cell. It contributes to normal development as well to carcinogenesis. Nowadays, many efforts are being made in order to use DNA methylation as a biomarker. The aim of our work is to characterize the expression and methylation of SIRT1, HIC1, BCL6, KLF4 and other genes relevant for Non-Hodgkin lymphomas (NHL) pathogenesis. Methods. Immunohistochemistry (IHC) on 72 formalin-fixed paraffin embedded tissue sections (FFPE). B-lymphocytes were purified from 36 biopsies of follicular hyperplasias (non-malignant B-lymphocytes), follicular lymphomas (FL) and diffuse large B-cell lymphomas (DLBCL). Gene expression were analysed by quantitative retrotranscribedPCR (qRTPCR). Quantitative CpG promoter methylation analysis was performed by pyrosequencing after bisulfite conversion or by Methyl II array qPCR on genomic DNA. Results. In a total of 72 FFPE samples of follicular hyperplasias (n = 17), FL (n = 36) and DLBCL (n = 19), SIRT1 staining is localized in the germinal center of the majority of follicular hyperplasias and FL samples. SIRT1 localizes preferentially in the centroblasts of the GC of the follicles where it correlates with Ki67. BCL6 is uniformly positive in follicular hyperplasias and FL, but heterogeneously distributed in DLBCL. Interestingly, SIRT1 and BCL6 expression correlate in FL.

By quantitative pyrosequencing we analyzed 3 CpG sites for the SIRT1 promoter (corresponding to the binding sites for CREB, ARID and PPARG transcription factors). Follicular hyperplasias display higher methylation levels (52.88%) than FL (38.36%) and DLBCL (32.65%) on SIRT1 promoter suggesting a possible inverse correlation between tumor aggressiveness and SIRT1 methylation.

Next, we selected a panel of genes whose expression is linked to lymphoma pathogenesis. By Methyl II array qPCR, we show that BCL6 methylation does not vary among samples. KLF4, DAPK1 and SPG20, show statistically significant methylation increases in FL and DLBCL compared to follicular hyperplasias, indicating a possible role of these proteins in lymphoma pathogenesis. On the contrary, no significant differences are observed for the other markers MZB1, MGMT, LMO2 and ASXL1. Notably, KLF4, DAPK1 and SPG20 mRNA expression levels anti-correlate with their promoter methylation in FL.

Conclusions. Epigenetic changes in SIRT1 methylation inversely correlate with NHL aggressiveness (decreasing in the order: follicular hyperplasias - FL - DLBCL), while KLF4, DAPK1 and SPG20 show a methylation increase that correlates with tumor aggressiveness. These data suggest that different patterns of methylation correlate with the clinical and prognostic parameters of these NHL subtypes.

Citation Format: Raffaele Frazzi, Eleonora Zanetti, Mariaelena Pistoni, Ione Tamagnini, Riccardo Valli, Francesco Merli. Different patterns of SIRT1, KLF4, DAPK1 and SPG20 methylation in B lymphocytes correlate with the clinical parameters of non-Hodgkin lymphoma subtypes. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4451.

Anti-Oxidant, Anti-Inflammatory and Anti-Angiogenic Properties of Resveratrol in Ocular Diseases

Resveratrol (3,4',5 trihydroxy-trans-stilbene) is one of the best known phytophenols with pleiotropic properties. It is a phytoalexin produced by vine and it leads to the stimulation of natural plant defenses but also exhibits many beneficial effects in animals and humans by acting on a wide range of organs and tissues. These include the prevention of cardiovascular diseases, anti-cancer potential, neuroprotective effects, homeostasia maintenance, aging delay and a decrease in inflammation. Age-related macular degeneration (AMD) is one of the main causes of deterioration of vision in adults in developed countries This review deals with resveratrol and ophthalmology by focusing on the antioxidant, anti-inflammatory, and anti-angiogenic effects of this molecule. The literature reports that resveratrol is able to act on various cell types of the eye by increasing the level of natural antioxidant enzymatic and molecular defenses. Resveratrol anti-inflammatory effects are due to its capacity to limit the expression of pro-inflammatory factors, such as interleukins and prostaglandins, and also to decrease the chemo-attraction and recruitment of immune cells to the inflammatory site. In addition to this, resveratrol was shown to possess anti-VEGF effects and to inhibit the proliferation and migration of vascular endothelial cells. Resveratrol has the potential to be used in a range of human ocular diseases and conditions, based on animal models and in vitro experiments.

Abstract 4652: Wide antiproliferative and proapoptotic activity of the natural prenyl-flavonoid Xanthohumol and its derivatives on cancer cells, peripheral blood mononuclear cells, and human primary endothelial cells

Chemo-preventive drugs are molecules able to prevent or retard cancer development and progression. Recently, diet flavonoids have been recognized as chemo- and angio-preventive agents. Among these, Xanthohumol (XN), is the principal prenylated chalcone of the female inflorescence of the hop plant (Humulus lupulus L.) with chemo-/angio-preventive properties. The biological effects of the chalcones mostly depend on their chemical structure, whose variations influence their anti-tumor effects. In order to identify novel potential chemo-/angio-preventive agents, we analyzed the effects of seven synthetic derivatives of XN on tumor and normal cells. We used different tumor cell lines (lymphoma, colon and prostate cancer cell lines) and healthy human primary cells (mononuclear cells isolated from peripheral blood (PBMCs) and umbilical vein endothelial cells (HUVEC)). XN derivatives have a lower IC50 on both cancer and normal cells as compared to XN. XN10 exerts the highest anti-proliferative activity in cancer and normal primary cells and we therefore focused our experiments on this compound in comparison with XN master molecule. Interestingly, the IC50 values for XN10 are two-three fold higher in primary cells than tumor cells, suggesting an anti-tumor effect of XN10 which spares healthy cells both from peripheral blood and the microenvironment. The treatment with XN10 leads to apoptosis as demonstrated in lymphoma cell lines by PARP-1 cleavage and dose-dependent caspase-3 activation. Preliminary data also show that XN downregulates the enzyme cyclooxygenase-1 while inducing a DNA damage as demonstrated by the increase of the specific marker γ-H2AX in the cell lysates treated with the indicated drugs. We then treated both PBMCs and HUVECs with XN and XN10 in a range of 1-20μM for 48 hr. XN10 affects PBMCs and HUVEC cells viability starting at lower doses (1 μM) than the parental molecule. 20μM XN mainly decreases monocyte population whereas XN10 affects both

CD19+/CD20+ and CD14+/CD33+ cells in parallel with the increase of apoptosis and caspase activation. Further, in HUVECs, XN activates AMPK in a time and dose-dependent manner with a peak of activation after 5 minutes of exposure up to 1h, independently from LKB1 activation. Activation of AMPK signalling pathway by XN was confirmed by ACC phosphorylation at Ser-79 at the same timepoints. In this cellular context, XN modulates AMPK downstream target, mTOR and eNOS, particularly inhibiting eNOS phosphorylation. Collectively, our data show that XN and its novel derivative XN10 exert a strong antiproliferative activity on a variety of tumor cell lines and normal cells. XN10 features the strongest pro-apoptotic activity yet causing the most dramatic cytotoxic effect on normal cells. Moreover, XN activity seems to involve AMPK activation, in HUVEC cells.

Citation Format: Katiuscia Dallaglio, Valentina Fragliasso, Cristina Gallo, Raffaele Frazzi, Clara Maccari, Armando Rossello, Adriana Albini. Wide antiproliferative and proapoptotic activity of the natural prenyl-flavonoid Xanthohumol and its derivatives on cancer cells, peripheral blood mononuclear cells, and human primary endothelial cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4652. doi:10.1158/1538-7445.AM2015-4652

Exploring new ways of regulation by resveratrol involving miRNAs, with emphasis on inflammation

This review presents recent evidence implicating microRNAs (miRNAs) in the beneficial effects of resveratrol (trihydroxystilbene), a nonflavonoid plant polyphenol, with emphasis on its anti-inflammatory effects. Many diseases and pathologies have been linked, directly or indirectly, to inflammation. These include infections, injuries, atherosclerosis, diabetes mellitus, obesity, cancer, osteoarthritis, age-related macular degeneration, demyelination, and neurodegenerative diseases. Resveratrol can both decrease the secretion of proinflammatory cytokines (e.g., IL-6, IL-8, and TNF-α) and increase the production of anti-inflammatory cytokines; it also decreases the expression of adhesion proteins (e.g., ICAM-1) and leukocyte chemoattractants (e.g., MCP-1). Resveratrol's primary targets appear to be the transcription factors AP-1 and NF-κB, as well as the gene COX2. Although no mechanistic link between any particular miRNA and resveratrol has been identified, resveratrol effects depend at least in part upon the modification of the expression of a variety of miRNAs that can be anti-inflammatory (e.g., miR-663), proinflammatory (e.g., miR-155), tumor suppressing (e.g., miR-663), or oncogenic (e.g., miR-21).

The multiple mechanisms of cell death triggered by resveratrol in lymphoma and leukemia

Lymphoma and leukemia represent a serious threat to human health and life expectancy. Resveratrol is, among the natural-derived chemopreventive molecules, one of the most effective and better studied. In this paper the main mechanisms of cell death triggered by- or linked to- resveratrol are reviewed and discussed. The main focus is on lymphoma and leukemia experimental models where resveratrol has been tested and investigated at the cellular, molecular or physiological levels. The most relevant in vivo challenges involving resveratrol are also reported and analyzed in order to define the key features of this polyphenol and the potential for the treatment of hematologic tumors.

Resveratrol-mediated apoptosis of hodgkin lymphoma cells involves SIRT1 inhibition and FOXO3a hyperacetylation

Resveratrol (RSV), a plant-derived stilbene, induces cell death in Hodgkin lymphoma (HL)-derived L-428 cells in a dose-dependent manner (IC50 = 27 μM, trypan blue exclusion assay). At a lower range (25 μM), RSV treatment for 48 hr causes arrest in the S-phase of the cell cycle, while at a higher concentration range (50 μM), apoptosis can be detected, with activation of caspase-3. The histone/protein deacetylase SIRT1 has been described as a putative target of RSV action in other model systems, even though its role in cancer cells is still controversial. Here we show that RSV, at both concentration ranges, leads to a marked increase in p53, while a decrease of SIRT1 expression level, as well as enzyme activity, only occurred at the higher concentration range. Concomitantly, however, treatments at both concentration ranges resulted in a marked increase in K373-acetylated p53 and lysine-acetylated FOXO3a. Immunohistochemical stainings of human lymph nodes show a preferential distribution of SIRT1 in the germinal center of the follicles while the mantle zone shows nearly no staining to few positive cells. The classical HL-affected lymph nodes show a strong positivity of the diagnostic Hodgkin Reed-Sternberg cells. Notably, both the HL-derived cell lines and the Hodgkin Reed-Sternberg cells of the affected lymph nodes derive from germinal center-derived B cells. The study of SIRT1 distribution and expression on a larger number of biopsies might disclose a novel role for this histone/protein deacetylase as therapeutic target.

Increase in clusterin forms part of the stress response in Hodgkin's lymphoma

Clusterin (also called APOJ, SGP-2, XIP8) has thus far been only partially characterized in lymphomas contrary to other types of cancer. Its expression has been reported only for anaplastic large cell lymphomas and, more recently, in mycosis fungoides. Here, we demonstrate an up-regulation of intracellular clusterin in Hodgkin's lymphoma (HL)-derived cell lines L-428, KM-H2 and L-540, caused by different stimuli such as IFN-γ, doxorubicin and X-rays. These stimuli are relevant for the pathophysiology and therapy of HL and represent a first step in the characterisation of this glycoprotein known to have a role in drug chemoresistance. p53 up-regulation accompanies increases in clusterin levels accordingly with the onset of apoptosis. We also show that the cells secrete more clusterin after treatment with doxorubicin, which is consistent with the observed intracellular increase. These observations suggested that the levels of circulating clusterin should also be measured in the peripheral blood from HL patients both at the time of diagnosis and after two cycles of chemotherapy. In a preliminary study on patient sera we observed that an increase in clusterin is correlated with positron emission tomography (PET) positivity after two cycles of chemotherapy.

Ex VivoProgramming of Antigen-Presenting B Lymphocytes: Considerations on DNA Uptake and Cell Activation

Plasmids used in DNA vaccination not only serve as a source of antigen, but also have an important adjuvant effect. This review focuses on recent advancements made in understanding how cells internalize DNA, and how internalized DNA activates immune response pathways. We also comment on the role of B cells in both of these processes.

Plasmid DNA and IL-4 modulate expression of mHC class I and costimulatory molecules in B lymphocytes

B lymphocytes are capable of spontaneous internalization of plasmid (p)DNA, an event that set in motion the antigen-presenting function in this class of hemopoietic cells. Previously, we showed that priming of CD8 T lymphocytes by spontaneously transgenic B lymphocytes requires T-cell help, and that this can be replaced by soluble IL-4. To better understand this phenomenon we studied the relative role of pDNA and IL-4 on the expression of MHC-I and a panel of critical costimulatory molecules (CD40, CD80, CD86, OX40L, and LAG-3). Whereas upregulation of MHC-I is contributed by pDNA, IL-4 mainly upregulates CD86 and to a lesser degree CD40. The two effects appear to be independent. In addition, however, it was found that IL-4 stabilizes MHC-I transcription in lymphocytes after spontaneous transgenesis with pDNA. These results further our understanding of events that take place in specialized mammalian cells after exposure to pDNA. They also point to the fact after pDNA internalization that the antigen-presenting function of B lymphocytes can be complemented by IL-4, a cytokine normally produced by activated CD4 T cells.

Protective Antifungal Yeast Killer Toxin-Like Antibodies

After several years of controversy, antibodies (Abs) are now believed to play an important role in the protection against fungal infections. Among them, recent data are strongly supporting the relevance of protective yeast killer toxin-like Abs ("antibiobodies", KT-Abs), which are able to exert a direct microbicidal activity by mimicking a killer toxin (PaKT) and its interaction with cell wall receptors on susceptible cells essentially constituted by beta-glucans. This review will focus on the implications of the yeast killer phenomenon, and, particularly, the occurrence and antimicrobial activity of protective antifungal KT-Abs, such as those produced during the course of experimental and natural infections caused by PaKT-sensitive microorganisms or produced by idiotypic vaccination with a PaKT-neutralizing mAb. The strong therapeutic activity exerted against different experimental mucosal and systemic mycoses by monoclonal and recombinant microbicidal KT-Abs (either in their soluble forms or expressed on human commensal bacteria) as well as by a synthetic killer peptide (KP, an antibody fragment engineered from the sequence of a recombinant KT-Ab) will be discussed. The surprisingly wide antimicrobial spectrum of activity against eukaryotic and prokaryotic pathogenic agents, such as fungi, bacteria and protozoa, of these Abs and Ab-derived molecules suggests new potential strategies for transdisease anti-infective prevention and therapy.

Engineered killer mimotopes: new synthetic peptides for antimicrobial therapy

This review deals with a novel approach to produce synthetic antibiotic peptides (killer mimotopes), similar to those described for the conversion of epitopes into peptide mimotopes, allowing their use as surrogate vaccines. Synthetic peptides pertaining to the complementary determining regions (CDRs) of a recombinant antiidiotypic antibody (PaKTscFv), which mimic the wide spectrum of microbicidal activity of a killer toxin produced by the yeast Pichia anomala (PaKT), have proven to act as structural or functional mimotopes of PaKT. This activity appeared to be mediated by interaction with specific cell wall killer toxin receptors (KTRs), mainly constituted by beta glucans. Killer mimotopes have shown in vitro an impressive microbicidal activity against Candida albicans. They were adopted as a model of PaKT- and PaKTscFv-susceptible microorganisms. Optimization through alanine scanning led to the generation of an engineered decapeptide (KP) of a CDR-L1 pertaining antibody fragment with an enhanced in vitro microbicidal activity. It had a potent therapeutic effect against experimental vaginal and systemic candidiasis in normal and immunodeficient mice caused by flucanozole susceptible and resistant yeast isolates. KP exerted a microbicidal activity in vitro against multidrug-resistant eukaryotic and prokaryotic pathogenic microorganisms, which was neutralized by interaction with laminarin (beta 1,3-glucan). To our knowledge, KP represents the prototype of an engineered peptide fragment derived from a microbicidal recombinant antiidiotypic antibody. It is capable of exerting antimicrobial activity in vitro and a therapeutic effect in vivo presumably acting through interaction with the beta glucan KTR component in the cell walls of pathogenic microorganisms.

Biotechnological approaches to the production of idiotypic vaccines and antiidiotypic antibiotics

The potential therapeutic activity of a killer toxin produced by the yeast Pichia anomala (PaKT) characterized by its wide spectrum of antimicrobial activity has been exploited through the simulation of its interaction with the specific cell wall receptor (KTR) of PaKT-sensitive microorganisms by the idiotypic network. Killer antiidiotypes (PaKTantiId) produced by idiotypic vaccination with a PaKT-neutralizing monoclonal antibody have proven to confer active and passive immunoprotection in experimental models of systemic and vaginal candidiasis. PaKTantiId-like human anti-KTR antibodies are naturally produced in infections caused by PaKT-sensitive microorganisms. PaKTantiId in its monoclonal and recombinant formats as well as expressed on human commensal bacteria have shown microbicidal activity in vitro and a therapeutic effect in experimental models of infection caused by PaKT-sensitive microorganisms. New perspectives of idiotypic vaccination and antiidiotypic antibiotic therapy and biotechnological approaches to the production of trandisease idiotypic vaccines and wide-spectrum antiidiotypic antibiotics (killer mimotopes) will be discussed as effective tools to fight epidemiologically important mucosal and systemic microbial infections.

New strategies for treatment of Candida vaginal infections

New strategies for treatment of vaginal candidiasis have been recently exploited, due to widespread occurrence of this disease, in particular as recurrent infections, limitations of safe and efficacious antifungals as well as the lack of reliable preventative approaches. In this review new chemotherapeutic and immunotherapeutic strategies, based on the improved understanding of the immunopathogenesis of this prevalent human infection, will be discussed. The role of killer antibodies (or their molecular derivatives), i.e. antibodies that show antibiotic activity bearing the internal image of a yeast killer toxin (KT), characterized by a wide spectrum of microbicidal activity, and of the specific cell wall KT receptor as putative new therapeutic agents and preventative or therapeutic vaccines, respectively, will be particularly outlined.

In vitro leishmanicidal activity of a monoclonal antibody mimicking a yeast killer toxin

The microbicidal effect of a monoclonal antiidiotypic antibody, mimicking the activity of a yeast killer toxin, characterized by a wide antimicrobial spectrum, has been evaluated in vitro against two relevant species of protozoan parasites, Leishmania major and Leishmania infantum. The antiidiotypic antibody exerted a significant and dose-dependent antileishmanial activity against parasite promastigotes in comparison to an irrelevant isotype-matched monoclonal antibody. This is the first demonstration that an antibody, which had been already shown to be fungicidal and bactericidal, may also exert a direct microbicidal activity against protozoa.

Inhibition by yeast killer toxin-like antibodies of oral Streptococci adhesion to tooth surfaces in an ex vivo model

BACKGROUND

Monoclonal (KTmAb) and recombinant (KTscFv) anti-idiotypic antibodies, representing the internal image of a yeast killer toxin, proved to be microbicidal in vitro against important eukaryotic and prokaryotic pathogens such as Candida albicans, Pneumocystis carinii, Mycobacterium tuberculosis, Staphylococcus aureus, S. haemolyticus, Enterococcus faecalis, E. faecium, and Streptococcus pneumoniae, including multidrug-resistant strains. KTmAb and KTscFv exerted a strong therapeutic effect in well-established animal models of candidiasis and pneumocystosis. Streptococcus mutans is the most important etiologic agent of dental caries that might result from the metabolic end products of dental plaque. Effective strategies to reduce the disease potential of dental plaque have considered the possibility of using antibiotics or antibodies against oral streptococci in general and S. mutans in particular. In this study, the activity of KTmAb and KTscFv against S. mutans and the inhibition and reduction by KTmAb of dental colonization by S. mutans and other oral streptococci in an ex vivo model of human teeth were investigated.

MATERIALS AND METHODS

KTscFv and KTmAb were used in a conventional colony forming unit (CFU) assay against a serotype C strain of S. mutans, and other oral streptococci (S. intermedius, S. mitis, S. oralis, S. salivarius). An ex vivo model of human teeth submerged in saliva was used to establish KTmAb potential of inhibiting or reducing the adhesion to dental surfaces by S. mutans and other oral streptococci.

RESULTS

KTmAb and KTscFv kill in vitro S. mutans and other oral streptococci. KTmAb inhibit colonization of dental surfaces by S. mutans and oral streptococci in the ex vivo model.

CONCLUSIONS

Killer antibodies with antibiotic activity or their engineered derivatives may have a potential in the prevention of dental caries in vivo.

The efficacy of acquired humoral and cellular immunity in the prevention and therapy of experimental fungal infections

In the past two decades, numerous studies have documented the importance of acquired immunity for host defense against invasive fungal infections. There is widespread consensus in the field of medical mycology that cellular immunity is critical for successful host defense against fungi. However, in recent years several studies have established the potential efficacy of humoral immunity in host protection against two major fungal pathogens: Candida albicans and Cryptococcus neoformans. For C. albicans, antibodies to mannan, proteases and a heat shock proteins have been associated with protection against infection. Furthermore, anti-idiotypic antibodies to antibodies recognizing killer toxin from Pichia anomala and mimicking natural anti-killer toxin receptor antibodies can protect against C. albicans and other microorganisms. For C. neoformans, antibodies to the capsular glucuronoxylomannan have been shown to mediate protection in animal models of infection. Vaccines that induce protective antibodies have been shown to protect against experimental C. albicans and C. neoformans infection. In contrast, humoral immunity has not yet been demonstrated to mediate protection against Coccidioides immitis. For C. immitis, protection against infection is thought to rely on T cell mediated immunity, and the emphasis is on identifying the antigens that stimulate protective cellular immune responses and several candidate vaccines have been identified. These results provide encouragement for the view that acquired immune responses can be mobilized for the prevention and treatment of fungal infections.

Killer anti-idiotypes in the control of fungal infections

Killer anti-idiotypes (KTantild) bear the internal image of a Pichia anomala toxin (KT), characterized by microbicidal activity against prokaryotic and eukaryotic pathogenic microorganisms presenting specific cell wall receptors (KTR). KTantiId produced by idiotypic vaccination with a KT-neutralizing monoclonal antibody confer active and passive immunoprotection in experimental models of systemic and vaginal candidiasis. KTantild-like human natural anti-KTR antibodies are produced in natural infections caused by KT-sensitive microorganisms. KTantiId in the monoclonal and recombinant forms show therapeutic activity in experimental vaginal candidiasis and Pneumocystis carinii pneumonia. Human commensal bacteria expressing KTantild or killer mimotopes synthesized from the sequence of KtantiId, may represent effective tools to combat fungal infections.

Controlled delivery of biotechnological products

Peptides, proteins, and nucleotides or DNA fragments are the new generation of drugs. They are becoming attractive owing to the fast development of biotechnology. The admnistration of such molecules, however, may be a problem as sensitivity to temperature, instability at some physiological pH values, short plasma half-life, and high molecular dimension, which hinders the diffusive transport, make, at the moment, parenteral route the only possible way of administration of such molecules. Controlled drug delivery that comprises the development of new administration routes could be the answer to the problems for administration of biotechnological molecules. The rational of drug delivery is to change the pharmacokinetic and pharmacodynamic of drugs by controlling their absorption and distribution. Rate and time of drug release at absorption site could be programmed using a so called delivery system. Different technologies, such as chemical (pro-drugs), biological, polymers, lipids (liposomes, LDL), have been proposed to obtain controlled drug release. Also the use of new administration routes is part of controlled drug delivery. In fact, it could increase the drug absorption and reduce the effects of the active ingredient in those districts not interested in the therapy. Drug delivery systems allowing for an effective release in vivo of new biotechnological molecules, such as recombinant antiidiotypic antibodies with antibiotic activity, devoted to the treatment of pulmonary (tuberculosis and pneumocystosis) and mucosal (candidiasis) diseases are discussed under that perspective.

In vitro activity of monoclonal and recombinant yeast killer toxin-like antibodies against antibiotic-resistant gram-positive cocci

BACKGROUND

Monoclonal (mAbKT) and recombinant single-chain (scFvKT) anti-idiotypic antibodies were produced to represent the internal image of a yeast killer toxin (KT) characterized by a wide spectrum of antimicrobial activity, including gram-positive cocci. Pathogenic eukaryotic and prokaryotic microorganisms, such as Candida albicans, Pneumocystis carinii, and a multidrug-resistant strain of Mycobacterium tuberculosis, presenting specific, although yet undefined, KT-cell wall receptors (KTR), have proven to be killed in vitro by mAbKT and scFvKT. mAbKT and scFvKT exert a therapeutic effect in vivo in experimental models of candidiasis and pneumocystosis by mimicking the functional activity of protective antibodies naturally produced in humans against KTR of infecting microorganisms. The swelling tide of concern over increasing bacterial resistance to antibiotic drugs gives the impetus to develop new therapeutic compounds against microbial threat. Thus, the in vitro bactericidal activity of mAbKT and scFvKT against gram-positive, drug-resistant cocci of major epidemiological interest was investigated.

MATERIALS AND METHODS

mAbKT and scFvKT generated by hybridoma and DNA recombinant technology from the spleen lymphocytes of mice immunized with a KT-neutralizing monoclonal antibody (mAb KT4) were used in a conventional colony forming unit (CFU) assay to determine, from a qualitative point of view, their bactericidal activity against Staphylococcus aureus, S. haemolyticus, Enterococcus faecalis, E. faecium, and Streptococcus pneumoniae strains. These bacterial strains are characterized by different patterns of resistance to antibiotics, including methicillin, vancomycin, and penicillin.

RESULTS

According to the experimental conditions adopted, no bacterial isolate proved to be resistant to the activity of mAbKT and scFvKT.

CONCLUSIONS

scFvKT exerted a microbicidal activity against multidrug resistant bacteria, which may represent the basis for the drug modeling of new antibiotics with broad antibacterial spectra to tackle the emergence of microbial resistance.