Molecular immunolabeling with recombinant single-chain variable fragment (scFv) antibodies designed with metal-binding domains

Sugar and ice: Immunoelectron microscopy using cryosections according to the Tokuyasu method

Since the pioneering work of Kiyoteru Tokuyasu in the 70ths the use of thawed cryosections prepared according to the "Tokuyasu-method" for immunoelectron microscopy did not lose popularity. We owe this method a whole subcellular world described by discrete gold particles pointing at cargo, receptors and organelle markers on delicate images of the inner life of a cell. Here we explain the procedure of sample preparation, sectioning and immunolabeling in view of recent developments and the reasoning behind protocols including some historical perspective. Cryosections are prepared from chemically fixed and sucrose infiltrated samples and labeled with affinity probes and electron dense markers. These sections are ideal substrates for immunolabeling, since antigens are not exposed to organic solvent dehydration or masked by resin. Instead, the structures remain fully hydrated throughout the labeling procedure. Furthermore, target molecules inside dense intercellular structural elements, cells and organelles are accessible to antibodies from the section surface. For the validation of antibody specificity several approaches are recommended including knock-out tissue and reagent controls. Correlative light and electron microscopy strategies involving correlative probes are possible as well as correlation of live imaging with the underlying ultrastructure. By applying stereology, gold labeling can be quantified and evaluated for specificity.

HIV Apheresis Tags (HIVAT) Aided Elimination of Viremia

INTRODUCTION

HIV viremia is the essential element for progression of an initial HIV infection into AIDS and death. The currently approved management relies primarily on chemotherapy repressing the HIV replication in the infected CD4+ cells, although with severe systemic adverse effects. The problem is that it does not physically eliminate viruses, which then not only keep infecting healthy cells of these patients, but also promote infections of other people.

SPECIFIC AIM

An overall objective of our work is biomolecular engineering of virus apheresis tags (VAT) that eliminate viremias without adverse effects. The specific aim of this project was biomolecular engineering of Human Immunodeficiency Virus Apheresis Tags (HIVAT): CD4-Au-Fe3O4, CD4-SiO2-Fe3O4, anti-gp120-Au-Fe3O4, and anti-gp120-SiO2-Fe3O4.

HEALTHY DONORS AND PATIENTS

Per the Institutional Review Board's approval and in compliance with Declaration of Helsinki, healthy donors and patients were presented with Patient Bill of Rights and provided Patient Informed Consent, while all the procedures were pursued by the licensed physicians.

MATERIALS AND METHODS

CD4, gp120, gp41, gp160, anti-gp120, p24 were transgenomically expressed. Superparamagnetic core-shell particles (SPM-CSP) were synthesized. SPM-CSP were used as the nucleation centers for assembling the expressed molecules upon them to create virus apheresis tags (VAT). VAT were injected into the blood or lymph acquired from the HIV+ and HBV+ patients followed by apheresis at 0.47 - 9.4 T. VAT efficacy in eliminating viremia was determined through immunoblots, NMR and q-RT-PCR.

RESULTS

Treatment of blood or lymph of the HIV+ patients' with VAT followed by virus apheresis resulted in rapid elimination of the HIV viremia. Efficacy of apheresis was contingent upon the gravity of viremia versus doses and regimens of VAT. Importantly, administration of VAT also effectively improved levels of non-infected CD4+ lymphocytes.

DISCUSSION / CONCLUSIONS

Herein, we present the proof of concept for a new, effective treatment with virus apheresis tags (VAT), specifically Human Immunodeficiency Virus Apheresis Tags (HIVAT), of the HIV+ patients' blood and lymph, which is eliminating the HIV viremia.It can be easily adapted as treatments of viremias perpetrated by other deadly viruses, which we vigorously pursue.

HIV Apheresis Tags (HIVAT) Aided Elimination of Viremia

INTRODUCTION

HIV viremia is the essential element for progression of an initial HIV infection into AIDS and death. The currently approved management relies primarily on chemotherapy repressing the HIV replication in the infected CD4+ cells, although with severe systemic adverse effects. The problem is that it does not physically eliminate viruses, which then not only keep infecting healthy cells of these patients, but also promote infections of other people.

SPECIFIC AIM

An overall objective of our work is biomolecular engineering of virus apheresis tags (VAT) that eliminate viremias without adverse effects. The specific aim of this project was biomolecular engineering of Human Immunodeficiency Virus Apheresis Tags (HIVAT): CD4-Au-Fe3O4, CD4-SiO2-Fe3O4, anti-gp120-Au-Fe3O4, and anti-gp120-SiO2-Fe3O4.

HEALTHY DONORS AND PATIENTS

Per the Institutional Review Board's approval and in compliance with Declaration of Helsinki, healthy donors and patients were presented with Patient Bill of Rights and provided Patient Informed Consent, while all the procedures were pursued by the licensed physicians.

MATERIALS AND METHODS

CD4, gp120, gp41, gp160, anti-gp120, p24 were transgenomically expressed. Superparamagnetic core-shell particles (SPM-CSP) were synthesized. SPM-CSP were used as the nucleation centers for assembling the expressed molecules upon them to create virus apheresis tags (VAT). VAT were injected into the blood or lymph acquired from the HIV+ and HBV+ patients followed by apheresis at 0.47 - 9.4 T. VAT efficacy in eliminating viremia was determined through immunoblots, NMR and q-RT-PCR.

RESULTS

Treatment of blood or lymph of the HIV+ patients' with VAT followed by virus apheresis resulted in rapid elimination of the HIV viremia. Efficacy of apheresis was contingent upon the gravity of viremia versus doses and regimens of VAT. Importantly, administration of VAT also effectively improved levels of non-infected CD4+ lymphocytes.

DISCUSSION / CONCLUSIONS

Herein, we present the proof of concept for a new, effective treatment with virus apheresis tags (VAT), specifically Human Immunodeficiency Virus Apheresis Tags (HIVAT), of the HIV+ patients' blood and lymph, which is eliminating the HIV viremia.It can be easily adapted as treatments of viremias perpetrated by other deadly viruses, which we vigorously pursue.

HIV Universal Vaccine

BACKGROUND

For many deadly viruses, there are no preventive and / or therapeutic vaccines approved by health authorities World-wide (e.g., HIV, Ebola, Dengue, and many others). Although, for some viruses, prophylactic vaccines are very effective (e.g., HBV, and many others).In this realm, we design, manufacture, test, and streamline into the clinics novel viral universal vaccines (VUV). VUV have such unique features, that medical vaccination or natural infection induced immunity against some viruses (e.g., HBV) upon the VUV's administration to the infected with other, different viruses patients, is redirected against these other, newly infecting viruses (e.g., HIV).

SPECIFIC AIM

The specific aim of this work was biomolecular engineering of the HIV universal vaccine comprising the two main functional domains: CD4 or anti-gp120 - as the HIV tagging domain and HBsAg - as the immune response eliciting domain, so that upon its administration the HBV medical immunization or natural infection induced immunity would be redirected, accelerated, and amplified to fight the HIV infection.

HEALTHY DONORS AND PATIENTS

Per the Institutional Review Board approval and in compliance with the Declaration of Helsinki, all healthy donors and patients were presented with the Patients' Bill of Rights and provided Patient Informed Consent. All the procedures were pursued by the licensed medical doctors.

METHODS & RESULTS

We have biomolecularly engineered HIV universal vaccine (HIVUV) comprising human CD4 or anti-gp120 and HBsAg of HBV. By immunoblotting and magnetic activated molecular sorting, we have demonstrated high specificity of this vaccine in binding HIV. By flow cytometry and nuclear magnetic resonance, we have demonstrated high efficacy of these vaccines to engage HBV immunized patients' immune system against HIV. Administration of HIVUV to blood or lymph of the HIV+ patients resulted in rapid reduction of the HIV viremia down to undetectable. It also resulted in protection of populations of CD4+ cells against HIV caused decline.

CONCLUSIONS

We have demonstrated the proof of concept for high efficacy of VUV, specifically HIVUV, in annihilating HIV. Nevertheless, the same compositions, processes, and methods, for persons skilled in biotechnology, pharmacogenomics, and molecular medicine, are adaptable for other deadly viral infections, which we vigorously pursue.

HIV Universal Vaccine

BACKGROUND

For many deadly viruses, there are no preventive and / or therapeutic vaccines approved by health authorities World-wide (e.g., HIV, Ebola, Dengue, and many others). Although, for some viruses, prophylactic vaccines are very effective (e.g., HBV, and many others).In this realm, we design, manufacture, test, and streamline into the clinics novel viral universal vaccines (VUV). VUV have such unique features, that medical vaccination or natural infection induced immunity against some viruses (e.g., HBV) upon the VUV's administration to the infected with other, different viruses patients, is redirected against these other, newly infecting viruses (e.g., HIV).

SPECIFIC AIM

The specific aim of this work was biomolecular engineering of the HIV universal vaccine comprising the two main functional domains: CD4 or anti-gp120 - as the HIV tagging domain and HBsAg - as the immune response eliciting domain, so that upon its administration the HBV medical immunization or natural infection induced immunity would be redirected, accelerated, and amplified to fight the HIV infection.

HEALTHY DONORS AND PATIENTS

Per the Institutional Review Board approval and in compliance with the Declaration of Helsinki, all healthy donors and patients were presented with the Patients' Bill of Rights and provided Patient Informed Consent. All the procedures were pursued by the licensed medical doctors.

METHODS & RESULTS

We have biomolecularly engineered HIV universal vaccine (HIVUV) comprising human CD4 or anti-gp120 and HBsAg of HBV. By immunoblotting and magnetic activated molecular sorting, we have demonstrated high specificity of this vaccine in binding HIV. By flow cytometry and nuclear magnetic resonance, we have demonstrated high efficacy of these vaccines to engage HBV immunized patients' immune system against HIV. Administration of HIVUV to blood or lymph of the HIV+ patients resulted in rapid reduction of the HIV viremia down to undetectable. It also resulted in protection of populations of CD4+ cells against HIV caused decline.

CONCLUSIONS

We have demonstrated the proof of concept for high efficacy of VUV, specifically HIVUV, in annihilating HIV. Nevertheless, the same compositions, processes, and methods, for persons skilled in biotechnology, pharmacogenomics, and molecular medicine, are adaptable for other deadly viral infections, which we vigorously pursue.

A novel immuno-gold labeling protocol for nanobody-based detection of HER2 in breast cancer cells using immuno-electron microscopy

Immuno-electron microscopy is commonly performed with the use of antibodies. In the last decade the antibody fragment indicated as nanobody (VHH or single domain antibody) has found its way to different applications previously done with conventional antibodies. Nanobodies can be selected to bind with high affinity and specificity to different antigens. They are small (molecular weight ca. 15kDa) and are usually easy to produce in microorganisms. Here we have evaluated the feasibility of a nanobody binding to HER2 for application in immuno-electron microscopy. To obtain highest labeling efficiency combined with optimal specificity, different labeling conditions were analysed, which included nanobody concentration, fixation and blocking conditions. The obtained optimal protocol was applied for post-embedment labeling of Tokuyasu cryosections and for pre-embedment labeling of HER2 for fluorescence microscopy and both transmission and scanning electron microscopy. We show that formaldehyde fixation after incubation with the anti-HER2 nanobody, improves labeling intensity. Among all tested blocking agents the best results were obtained with a mixture of cold water fish gelatine and acetylated bovine serum albumin, which prevented a-specific interactions causing background labeling while preserving specific interactions at the same time. In conclusion, we have developed a nanobody-based protocol for immuno-gold labeling of HER2 for Tokuyasu cryosections in TEM as well as for pre-embedment gold labeling of cells for both TEM and SEM.

Novel paradigm for immunotherapy of breast cancer by engaging prophylactic immunity against hepatitis B

BACKGROUND

Immunotherapy of patients suffering from the human epidermal growth factor receptor 2 overexpressing (HER-2(+)) breast cancers with the anti-HER-2 antibodies results in increase of the patients' overall survival. However, no prophylactic vaccine is available against HER-2(+) breast cancers. Although, prophylactic vaccine for human hepatitis B virus (HBV) is very effective.

SPECIFIC AIM

The specific aim of this work was to design, synthesize, and test bio-molecules which would engage prophylactic immunity against hepatitis B virus towards killing breast cancers cells.

METHODS AND RESULTS

By biomolecular engineering, we have created a novel family of biomolecules: antibody (anti-HER-2) × vaccine (HBsAg) engineered constructs (AVEC: anti-HER-2 × HBsAg). These biomolecules were utilized for redirecting, accelerating, and amplifying of the vaccination-induced, prophylactic immunity originally targeted against HBV as therapeutic immunity, newly targeted against HER-2(+) breast cancers. Treatment of the HER-2(+) breast cancer cells with AVEC: anti-HER-2 × HBsAg in blood of the patients, vaccinated with HBsAg, rapidly increased efficacy of killing of HER-2(+) breast cancer cells over that attained with the naked anti-HER-2 antibodies.

CONCLUSION

Novel antibody-vaccine engineered constructs (AVEC) facilitate redirecting, accelerating, and amplifying of prophylactic, HBV vaccination-induced immunity as immunotherapy (RAAVIIT) of HER-2(+) breast cancer. We currently streamline this novel therapeutic paradigm into clinical trials of breast and other cancers.

Novel paradigm for immunotherapy of ovarian cancer by engaging prophylactic immunity against hepatitis B virus

BACKGROUND

Only eight women out of one hundred diagnosed with ovarian epithelial cancers, which progressed to the clinical stage IV, survive 10 years. First line therapies: surgery, chemotherapy, and radiation therapy inflict very serious iatrogenic consequences. Passive immunotherapy of ovarian cancers offers only low efficacy. Prophylactic and therapeutic vaccines for ovarian cancers are not available. Interestingly, prophylactic vaccines for Hepatitis B Viruses (HBV) are very effective.

SPECIFIC AIM

The specific aim of this work was to design, synthesize, and administer biomolecules, which would engage prophylactic, vaccination-induced immunity for HBV towards killing of ovarian cancer cells with high specificity and efficacy.

PATIENTS

Tissue biopsies, ascites, and blood were acquired from the patients, whose identities were entirely concealed in accordance with the Declaration of Helsinki, pursuant to the Institutional Review Board approval, and with the Patients' informed consent.

METHODS AND RESULTS

By biomolecular engineering, we have created a novel family of biomolecules: antibody × vaccine engineered constructs (AVEC: anti-HER-2 × HBsAg). We have collected the blood from the volunteers, and measured the titers of anti-HBV antibodies resulting from the FDA approved and CDC scheduled HBV vaccinations. We have acquired tumor biopsies, ascites, and blood from patients suffering from the advanced ovarian cancers. We have established cultures of HER-2 over-expressing epithelial ovarian cancers: OV-90, TOC-112D, SKOV-3, as well as human ovary surface epithelial (HOSE) and human artery endothelial (HAE) cells. Treatment of the HER-2+ ovarian cancer cells with AVEC: anti-HER-2 × HBsAg, accompanied by administration of blood drawn from patients with high titers of the anti-HBV antibodies, resulted in much higher therapeutic efficacy as compared to treatment with the naked anti-HER-2 antibodies alone and/or with the relevant isotype antibodies. This treatment had practically no effect upon the HOSE and HAE cells.

DISCUSSION

Herein, we report attaining the great improvement in eradication efficacy of ovarian epithelial cancer cells' by engaging prophylactic immunity against HBV; thus creating a novel paradigm for immunotherapy of ovarian cancer. We have accomplished that by designing, synthesis, and administration of AVEC. Therefore, the HBV vaccination acquired immunity mounts immune response against the vaccine, but AVEC redirect, accelerate, and amplify this immune response of all the elements of the native and adaptive immune system against ovarian cancer. Our novel paradigm of immunotherapy is currently streamlined to clinical trials also of other cancers, while also engaging prophylactic and acquired immunity.

CONCLUSION

Novel antibody-vaccine engineered constructs (AVEC) create the solid foundation for redirected, accelerated, and amplified prophylactic, HBV vaccination-induced immunity immunotherapy (RAAVIIT) of ovarian cancers.

Multimodal Imaging of Chemically Fixed Cells in Preparation for NanoSIMS

In this work, we have employed time-of-flight secondary ion mass spectrometry (ToF-SIMS) to image chemically fixed adrenal cells prepared for transmission electron microscopy (TEM) and subsequent high-spatial-resolution NanoSIMS imaging. The sample fixation methodology preserves cell morphology, allows analysis in the ultrahigh vacuum environment, and reduces topographic artifacts, thus making these samples particularly favorable for ToF-SIMS analysis. ToF-SIMS imaging enables us to determine the chemistry and preservation capabilities of the chemical fixation as well as to locate specific ion species from OsO4. The OsO4 species have been localized in lysosomes of cortical cells, a type of adrenal cell present in the culture. NanoSIMS imaging of the (190)Os(16)O(-) ion species in cortical cells reveals the same localization as a wide range of OsO4 ions shown with ToF-SIMS. Even though we did not use during NanoSIMS imaging the exact OsxOy(-) ion species discovered with ToF-SIMS, ToF-SIMS allowed us to define the specific subcellular features in a high spatial resolution imaging mode. This study demonstrates the possibility for application of ToF-SIMS as a screening tool to optimize high-resolution imaging with NanoSIMS, which could replace TEM for localization in ultrahigh resolution imaging analyses.

'Above all, do no harm': safeguarding pluripotent stem cell therapy against iatrogenic tumorigenesis

Human pluripotent stem cells are the foundations of regenerative medicine. However, the worst possible complication of using pluripotent stem cells in therapy could be iatrogenic cancerogenesis. Nevertheless, despite the rapid progress in the development of new techniques for induction of pluripotency and for directed differentiation, risks of cancerogenic transformation of therapeutically implanted pluripotent stem cells still persist. 'Above all, do no harm', as quoted from the Hippocratic Oath, is our ultimate creed. Therefore, the primary goal in designing any therapeutic regimes involving stem cells should be the elimination of any possibilities of their neoplasmic transformation. I review here the basic strategies that have been designed to attain this goal: sorting out undifferentiated, pluripotent stem cells with antibodies targeting surface-displayed biomarkers; sorting in differentiating cells, which express recombinant proteins as reporters; killing undifferentiated stem cells with toxic antibodies or antibody-guided toxins; eliminating undifferentiated stem cells with cytotoxic drugs; making potentially tumorigenic stem cells sensitive to pro-drugs by transformation with suicide-inducing genes; eradication of differentiation-refractive stem cells by self-triggered transgenic expression of human recombinant DNases. Every pluripotent undifferentiated stem cell poses a risk of neoplasmic transformation. Therefore, the aforementioned or other novel strategies that would safeguard against iatrogenic transformation of these stem cells should be considered for incorporation into every stem cell therapy trial.

Directed cardiomyogenesis of autologous human induced pluripotent stem cells recruited to infarcted myocardium with bioengineered antibodies

OBJECTIVE

Myocardial infarctions constitute a major factor contributing to non-natural mortality world-wide. Clinical trials of myocardial regenerative therapy, currently pursued by cardiac surgeons, involve administration of stem cells into the hearts of patients suffering from myocardial infarctions. Unfortunately, surgical acquisition of these cells from bone marrow or heart is traumatic, retention of these cells to sites of therapeutic interventions is low, and directed differentiation of these cells in situ into cardiomyocytes is difficult. The specific aims of this work were: (1) to generate autologous, human, pluripotent, induced stem cells (ahiPSCs) from the peripheral blood of the patients suffering myocardial infarctions; (2) to bioengineer heterospecific antibodies (htAbs) and use them for recruitment of the ahiPSCs to infarcted myocardium; (3) to initiate in situ directed cardiomyogenesis of the ahiPSCs retained to infarcted myocardium.

METHODS

Peripheral blood was drawn from six patients scheduled for heart transplants. Mononuclear cells were isolated and reprogrammed, with plasmids carrying six genes (NANOG, POU5F1, SOX2, KLF4, LIN28A, MYC), to yield the ahiPSCs. Cardiac tissues were excised from the injured hearts of the patients, who received transplants during orthotopic surgery. These tissues were used to prepare in vitro models of stem cell therapy of infarcted myocardium. The htAbs were bioengineered, which simultaneously targeted receptors displayed on pluripotent stem cells (SSEA-4, SSEA-3, TRA-1-60, TRA-1-81) and proteins of myocardial sarcomeres (myosin, α-actinin, actin, titin). They were used to bridge the ahiPSCs to the infarcted myocardium. The retained ahiPSCs were directed with bone morphogenetic proteins and nicotinamides to differentiate towards myocardial lineage.

RESULTS

The patients' mononuclear cells were efficiently reprogrammed into the ahiPSCs. These ahiPSCs were administered to infarcted myocardium in in vitro models. They were recruited to and retained at the treated myocardium with higher efficacy and specificity, if were preceded with the htAbs, than with isotype antibodies or plain buffers. The retained cells differentiated into cardiomyocytes.

CONCLUSIONS

The proof of concept has been attained, for reprogramming the patients' blood mononuclear cells (PBMCs) into the ahiPSCs, recruiting these cells to infarcted myocardium, and initiating their cardiomyogenesis. This novel strategy is ready to support the ongoing clinical trials aimed at regeneration of infarcted myocardium.

Directed cardiomyogenesis of autologous human induced pluripotent stem cells recruited to infarcted myocardium with bioengineered antibodies

Objective

Myocardial infarctions constitute a major factor contributing to non-natural mortality world-wide. Clinical trials ofmyocardial regenerative therapy, currently pursued by cardiac surgeons, involve administration of stem cells into the hearts of patients suffering from myocardial infarctions. Unfortunately, surgical acquisition of these cells from bone marrow or heart is traumatic, retention of these cells to sites of therapeutic interventions is low, and directed differentiation of these cells in situ into cardiomyocytes is difficult. The specific aims of this work were: (1) to generate autologous, human, pluripotent, induced stem cells (ahiPSCs) from the peripheral blood of the patients suffering myocardial infarctions; (2) to bioengineer heterospecific tetravalent antibodies (htAbs) and use them for recruitment of the ahiPSCs to infarcted myocardium; (3) to initiate in situ directed cardiomyogenesis of the ahiPSCs retained to infarcted myocardium.

Methods

Peripheral blood was drawn from six patients scheduled for heart transplants. Mononuclear cells were isolated and reprogrammed, with plasmids carrying six genes (NANOG, POU5F1, SOX2, KLF4, LIN28A, MYC), to yield the ahiPSCs. Cardiac tissues were excised from the injured hearts of the patients, who received transplants during orthotopic surgery. These tissues were used to prepare in vitro model of stem cell therapy of infarcted myocardium. The htAbs were bioengineered, which simultaneously targeted receptors displayed on pluripotent stem cells (SSEA-4, SSEA-3, TRA-1-60, TRA-1-81) and proteins of myocardial sarcomeres (myosin, α-actinin, actin, titin). They were used to bridge the ahiPSCs to the infarcted myocardium. The retained ahiPSCs were directed with bone morphogenetic proteins and nicotinamides to differentiate towards myocardial lineage.

Results

The patients’ mononuclear cells were efficiently reprogrammed into the ahiPSCs. These ahiPSCs were administered to infarcted myocardium in in vitro models. They were recruited to and retained at the treated myocardium with higher efficacy and specificity, if were preceded the htAbs, than with isotype antibodies or plain buffers. The retained cells differentiated into cardiomyocytes.

Conclusions

The proof of concept has been attained, for reprogramming the patients’ blood mononuclear cells (PBMCs) into the ahiPSCs, recruiting these cells to infarcted myocardium, and initiating their cardiomyogenesis. This novel strategy is ready to support the ongoing clinical trials aimed at regeneration of infarcted myocardium.

Recruitment and retention of human autologous CD34+ CD117+ CD133+ bone marrow stem cells to infarcted myocardium followed by directed vasculogenesis: Novel strategy for cardiac regeneration

BACKGROUND

Ongoing clinical trials, in regenerative therapy of patients suffering from myocardial infarctions, rely primarily upon administration of bone marrow stem cells to the infarcted zones. Unfortunately, low retention of these cells, to the therapeutic delivery sites, reduces effectiveness of this strategy; thus it has been identified as the most critical problem for advancement of cardiac regenerative medicine.

SPECIFIC AIMS

The specific aim of this work was three-fold: (1) to isolate highly viable populations of human, autologous CD34+, CD117+, and CD133+ bone marrow stem cells; (2) to bioengineer heterospecific, tetravalent antibodies and to use them for recruiting of the stem cells to regenerated zones of infarcted myocardium; (3) to direct vasculogenesis of the retained stem cells with the defined factors.

PATIENTS METHODS

Cardiac tissue was biopsied from the hearts of the patients, who were receiving orthotopic heart transplants after multiple cardiac infarctions. This tissue was used to engineer fully human in vitro models of infarcted myocardium. Bone marrow was acquired from these patients. The marrow cells were sorted into populations of cells displaying CD34, CD117, and CD133. Heterospecific, tetravalent antibodies were bioengineered to bridge CD34, CD117, CD133 displayed on the stem cells with cardiac myosin of the infarcted myocardium. The sorted stem cells were administered to the infarcted myocardium in the in vitro models.

RESULTS

Administration of the bioengineered, heterospecific antibodies preceding administration of the stem cells greatly improved the stem cells' recruitment and retention to the infarcted myocardium. Treatment of the retained stem cells with vascular endothelial growth factor and angiopoietin efficiently directed their differentiation into endothelial cells, which expressed vascular endothelial cadherin, platelet / endothelial cell adhesion molecule, claudin, and occludin, while forming tight and adherens junctions.

CONCLUSIONS

This novel strategy improved retention of the patients' autologous bone marrow stem cells to the infarcted myocardium followed by directed vasculogenesis. Therefore, it is worth pursuing it in support of the ongoing clinical trials of cardiac regenerative therapy.

Eradication of Human Ovarian Cancer Cells by Transgenic Expression of Recombinant DNASE1, DNASE1L3, DNASE2, and DFFB Controlled by EGFR Promoter: Novel Strategy for Targeted Therapy of Cancer

Introduction

Ovarian cancer is the most deadly among all gynecological cancers. Patients undergoing systemic therapies of advanced ovarian cancers suffer from horrendous side effects. Cancer survivors and their offspring suffer from iatrogenic consequences of systemic therapies: genetic mutations. The ultimate goal of our work is development of therapies, which selectively and completely eliminate cancer cells, but do not harm healthy cells. An important consideration for attaining this goal is the fact that ovarian cancer cells over-express EGFR or its mutants, what becomes the factor discriminating them from healthy cells - a potential facilitator of personalized therapy.

Specific aim

The specific aim of this project was threefold: (1) to bioengineer suicide genes’ carrying vectors guided by synthetic antibodies for EGFRvIII and EGFR; (2) to genetically engineer DNA constructs for the human, recombinant DNASE1, DNASE1L3, DNASE2, and DFFB controlled by the EGFR promoter; (3) to selectively eradicate ovarian cancer cells by intranuclear targeting of the transgenically expressed recombinant DNases.

Methods

Synthetic antibodies for EGFR and EGFRvIII were selected from the human library and used to bioengineer biotag-guided transgenes’ vectors. Coding sequences for the human DNASE1, DNASE1L3, DNASE2, DFFB controlled by the EGFR promoter were amplified from the human cDNA and genetically engineered into the plasmid constructs also coding for the fusions with NLS and GFP. The vectors carrying transgenes for the DNases were delivered in vitro into human ovarian cancer cells from ascites and cultures.

Results

Synthetic antibody guided vectors delivered the transgenes for the recombinant DNases efficiently into the ovarian cancer cells. Transgenic expression and nuclear targeting of the DNases in those cells resulted in destruction of their genomes and led to their death, as validated by labeling with the molecular death tags. In healthy cells, which did not over-express EGFR, no changes were recorded.

Conclusion

Targeted expression of the recombinant DNASE1, DNASE1L3, DNASE2, DFFB in the ovarian cancers in vitro resulted in their complete eradication, but had no effects upon the healthy cells. This novel therapeutic strategy has a potential for streamlining it into in vivo trials, as personalized, targeted therapy of ovarian and other cancers.

Improved targeting and enhanced retention of the human, autologous, fibroblast-derived, induced, pluripotent stem cells to the sarcomeres of the infarcted myocardium with the aid of the bioengineered, heterospecific, tetravalent antibodies

Clinical trials, to regenerate the human heart injured by myocardial infarction, involve the delivery of stem cells to the site of the injury. However, only a small fraction of the introduced stem cells are detected at the site of the injury, merely two weeks after this therapeutic intervention. This significantly hampers the effectiveness of the stem cell therapy. To resolve the aforementioned problem, we genetically and molecularly bioengineered heterospecific, tetravalent antibodies (htAbs), which have both exquisite specificity and high affinity towards human, pluripotent, stem cells through the htAbs' domains binding SSEA-4, SSEA-3, TRA-1-60, and TRA-1-81, as well as towards the injured cardiac muscle through the htAbs' domains binding human cardiac myosin, α-actinin, actin, and titin. The cardiac tissue was acquired from the patients, who were receiving heart transplants. The autologous, human, induced, pluripotent stem cells (hiPSCs) were generated from the patients' fibroblasts by non-viral delivery and transient expression of the DNA constructs for: Oct4, Nanog, Sox2, Lin28, Klf4, c-Myc. In the trials involving the htAbs, the human, induced, pluripotent stem cells anchored to the myocardial sarcomeres with the efficiency, statistically, significantly higher, than in the trials with non-specific or without antibodies (p < 0.0003). Moreover, application of the htAbs resulted in cross-linking of the sarcomeric proteins to create the stable scaffolds for anchoring of the stem cells. Thereafter, these human, induced pluripotent stem cells differentiated into cardiomyocytes at their anchorage sites. By bioengineering of these novel heterospecific, tetravalent antibodies and using them to guide and to anchor the stem cells specifically to the stabilized sarcomeric scaffolds, we demonstrated the proof of concept in vitro for improving effectiveness of regenerative therapy of myocardial infarction and created the foundations for the trials in vivo.

Suicide Gene Therapy for Cancer - Current Strategies

Current cancer treatments may create profound iatrogenic outcomes. The adverse effects of these treatments still remain, as the serious problems that practicing physicians have to cope with in clinical practice. Although, non-specific cytotoxic agents constitute an effective treatment modality against cancer cells, they also tend to kill normal, quickly dividing cells. On the other hand, therapies targeting the genome of the tumors are both under investigation, and some others are already streamlined to clinical practice. Several approaches have been investigated in order to find a treatment targeting the cancer cells, while not affecting the normal cells. Suicide gene therapy is a therapeutic strategy, in which cell suicide inducing transgenes are introduced into cancer cells. The two major suicide gene therapeutic strategies currently pursued are: cytosine deaminase/5-fluorocytosine and the herpes simplex virus/ganciclovir. The novel strategies include silencing gene expression, expression of intracellular antibodies blocking cells' vital pathways, and transgenic expression of caspases and DNases. We analyze various elements of cancer cells' suicide inducing strategies including: targets, vectors, and mechanisms. These strategies have been extensively investigated in various types of cancers, while exploring multiple delivery routes including viruses, non-viral vectors, liposomes, nanoparticles, and stem cells. We discuss various stages of streamlining of the suicide gene therapy into clinical oncology as applied to different types of cancer. Moreover, suicide gene therapy is in the center of attention as a strategy preventing cancer from developing in patients participating in the clinical trials of regenerative medicine. In oncology, these clinical trials are aimed at regenerating, with the aid of stem cells, of the patients' organs damaged by pathologic and/or iatrogenic factors. However, the stem cells carry the risk of neoplasmic transformation. We discuss cell suicide inducing strategies aimed at preventing stem cell-originated cancerogenesis.

Recruitment and retention of human autologous CD34+ CD117+ CD133+ bone marrow stem cells to infarcted myocardium followed by directed vasculogenesis: Novel strategy for cardiac regeneration

Background

Ongoing clinical trials, in regenerative therapy of patients suffering from myocardial infarctions, rely primarily upon administration of bone marrow stem cells to the infarcted zones. Unfortunately, low retention of these cells, to the therapeutic delivery sites, reduces effectiveness of this strategy; thus it has been identified as the most critical problem for advancement of cardiac regenerative medicine.

Specific aims

The specific aim of this work was three-fold: (1) to isolate highly viable populations of human, autologous CD34+, CD117+, and CD133+ bone marrow stem cells; (2) to bioengineer heterospecific, tetravalent antibodies and to use them for recruiting of the stem cells to regenerated zones of infarcted myocardium; (3) to direct vasculogenesis of the retained stem cells with the defined factors.

Patients methods

Cardiac tissue was biopsied from the hearts of the patients, who were receiving orthotopic heart transplants after multiple cardiac infarctions. This tissue was used to engineer fully human in vitro models of infarcted myocardium. Bone marrow was acquired from these patients. The marrow cells were sorted into populations of cells displaying CD34, CD117, and CD133. Heterospecific, tetravalent antibodies were bioengineered to bridge CD34, CD117, CD133 displayed on the stem cells with cardiac myosin of the infarcted myocardium. The sorted stem cells were administered to the infarcted myocardium in the in vitro models.

Results

Administration of the bioengineered, heterospecific antibodies preceding administration of the stem cells greatly improved the stem cells’ recruitment and retention to the infarcted myocardium. Treatment of the retained stem cells with vascular endothelial growth factor and angiopoietin efficiently directed their differentiation into endothelial cells, which expressed vascular endothelial cadherin, platelet/endothelial cell adhesion molecule, claudin, and occludin, while forming tight and adherens junctions.

Conclusions

This novel strategy improved retention of the patients’ autologous bone marrow cells to the infarcted myocardium followed by directed vasculogenesis. Therefore, it is worth pursuing it in support of the ongoing clinical trials of cardiac regenerative therapy.

Safeguarding Stem Cell-Based Regenerative Therapy against Iatrogenic Cancerogenesis: Transgenic Expression of DNASE1, DNASE1L3, DNASE2, DFFB Controlled By POLA1 Promoter in Proliferating and Directed Differentiation Resisting Human Autologous Pluripotent Induced Stem Cells Leads to their Death

Introduction

The worst possible complication of using stem cells for regenerative therapy is iatrogenic cancerogenesis. The ultimate goal of our work is to develop a self-triggering feedback mechanism aimed at causing death of all stem cells, which resist directed differentiation, keep proliferating, and can grow into tumors.

Specific aim

The specific aim was threefold: (1) to genetically engineer the DNA constructs for the human, recombinant DNASE1, DNASE1L3, DNASE2, DFFB controlled by POLA promoter; (2) to bioengineer anti-SSEA-4 antibody guided vectors delivering transgenes to human undifferentiated and proliferating pluripotent stem cells; (3) to cause death of proliferating and directed differentiation resisting stem cells by transgenic expression of the human recombinant the DNases (hrDNases).

Methods

The DNA constructs for the human, recombinant DNASE1, DNASE1L3, DNASE2, DFFB controlled by POLA promoter were genetically engineered. The vectors targeting specifically SSEA-4 expressing stem cells were bioengineered. The healthy volunteers’ bone marrow mononuclear cells (BMMCs) were induced into human, autologous, pluripotent stem cells with non-integrating plasmids. Directed differentiation of the induced stem cells into endothelial cells was accomplished with EGF and BMP. The anti-SSEA 4 antibodies’ guided DNA vectors delivered the transgenes for the human recombinant DNases’ into proliferating stem cells.

Results

Differentiation of the pluripotent induced stem cells into the endothelial cells was verified by highlighting formation of tight and adherens junctions through transgenic expression of recombinant fluorescent fusion proteins: VE cadherin, claudin, zona occludens 1, and catenin. Proliferation of the stem cells was determined through highlighting transgenic expression of recombinant fluorescent proteins controlled by POLA promoter, while also reporting expression of the transgenes for the hrDNases. Expression of the transgenes for the DNases resulted in complete collapse of the chromatin architecture and degradation of the proliferating cells’ genomic DNA. The proliferating stem cells, but not the differentiating ones, were effectively induced to die.

Conclusion

Herein, we describe attaining the proof-of-concept for the strategy, whereby transgenic expression of the genetically engineered human recombinant DNases in proliferating and directed differentiation resisting stem cells leads to their death. This novel strategy reduces the risk of iatrogenic neoplasms in stem cell therapy.

TRA-1-60+, SSEA-4+, POU5F1+, SOX2+, NANOG+ Clones of Pluripotent Stem Cells in the Embryonal Carcinomas of the Testes

INTRODUCTION

Cancer of the testes is currently the most frequent neoplasm and a leading cause of morbidity in men 15-35 years of age. Its incidence is increasing. Embryonal carcinoma is its most malignant form, which either may be resistant or may develop resistance to therapies, which results in relapses. Cancer stem cells are hypothesized to be drivers of these phenomena.

SPECIFIC AIM

The specific aim of this work was identification and isolation of spectra of single, living cancer stem cells, which were acquired directly from the patients' biopsies, followed by testing of their pluripotency.

PATIENTS METHODS

Biopsies were obtained from the patients with the clinical and histological diagnoses of the primary, pure embryonal carcinomas of the testes. The magnetic and fluorescent antibodies were genetically engineered. The SSEA-4 and TRA-1-60 cell surface display was analyzed by multiphoton fluorescence spectroscopy (MPFS), flow cytometry (FCM), immunoblotting (IB), nuclear magnetic resonance spectroscopy (NMRS), energy dispersive x-ray spectroscopy (EDXS), and total reflection x-ray spectroscopy (TRXFS). The single, living cells were isolated by magnetic or fluorescent sorting followed by their clonal expansion. The OCT4A, SOX2, and NANOG genes' transcripts were analyzed by qRTPCR and the products by IB and MPFS.

RESULTS

The clones of cells, with the strong surface display of TRA-1-60 and SSEA-4, were identified and isolated directly from the biopsies acquired from the patients diagnosed with the pure embryonal carcinomas of the testes. These cells demonstrated high levels of transcription and translation of the pluripotency genes: OCT4A, SOX2, and NANOG. They formed embryoid bodies, which differentiated into ectoderm, mesoderm, and endoderm.

CONCLUSION

In the pure embryonal carcinomas of the testes, acquired directly from the patients, we identified, isolated with high viability and selectivity, and profiled the clones of the pluripotent stem cells. These results may help in explaining therapy-resistance and relapses of these neoplasms, as well as, in designing targeted, personalized therapy.

Selection of Ceratitis capitata (Diptera: Tephritidae) specific recombinant monoclonal phage display antibodies for prey detection analysis

Several recombinant antibodies against the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), one of the most important pests in agriculture worldwide, were selected for the first time from a commercial phage display library of human scFv antibodies. The specificity and sensitivity of the selected recombinant antibodies were compared with that of a rabbit polyclonal serum raised in parallel using a wide range of arthropod species as controls. The selected recombinant monoclonal antibodies had a similar or greater specificity when compared with classical monoclonal antibodies. The selected recombinant antibodies were successfully used to detect the target antigen in the gut of predators and the scFv antibodies were sequenced and compared. These results demonstrate the potential for recombinant scFv antibodies to be used as an alternative to the classical monoclonal antibodies or even molecular probes in the post-mortem analysis studies of generalist predators.

TRA-1-60+, SSEA-4+, Oct4A+, Nanog+ Clones of Pluripotent Stem Cells in the Embryonal Carcinomas of the Ovaries

INTRODUCTION

Embryonal carcinoma of the ovary (ECO), pure or admixed to other tumors, is the deadly gynecological cancer.

SPECIFIC AIM

The specific aim of this work was identification, isolation, clonal expansion, and molecular profiling of the pluripotent cells in the embryonal carcinomas of the ovaries.

PATIENTS METHODS

The samples were acquired from the patients, who were clinically and histopathologically diagnosed with the advanced, pure embryonal carcinomas of the ovaries. The cell surface display of the TRA-1-60 and SSEA-4 was analyzed by flow cytometry (FCM), immunoblotting (IB), multiphoton fluorescence spectroscopy (MPFS), nuclear magnetic resonance spectroscopy (NMRS), and total reflection x-ray spectroscopy (TRXFS). The transcripts of the Oct4A and Nanog were analyzed by qRTPCR and MPFS and the products by MPFS. The human pluripotent, embryonic stem cells (ESC), human pluripotent, embryonal carcinoma of the testes (ECT), healthy tissues of the ovary (HTO), healthy tissue of testes (HTT), peripheral blood mononuclear cells (PBMC), and bone marrow mononuclear cells (BMMC) served as the controls.

RESULTS

The studied embryonal carcinomas of the ovaries (ECOs) contained the cells with the strong surface display of the TRA-1-60 and SSEA-4, which was similar to the pluripotent ESC and ECT. Their morphology was consistent with the histopathological diagnosis. Moreover, these cells showed strong expression of the Oct4A and Nanog, which was similar to the pluripotent ESC and ECT. The ECO cells formed embryoid bodies, which differentiated into ectoderm, mesoderm, and endoderm. These cells were induced to differentiate into muscles, epithelia, and neurons.

CONCLUSION

Herein, we revealed presence and identified molecular profiles of the clones of the pluripotent stem cells in the embryonal carcinomas of the ovaries. These results should help us with refining molecular diagnoses of these deadly neoplasms and design biomarker-targeted, patient-centered, personalized therapy.

Routing of Biomolecules and Transgenes' Vectors in Nuclei of Oocytes

The molecular architecture of Nuclear Pore Complexes (NPCs), as well as the import and export of molecules through them, has been intensively studied in a variety of cells, including oocytes. However, the structures and mechanisms, involved in the transport of molecules beyond the NPCs, remained unclear, until now. The specific aim of this work was, therefore, to determine, if there exist any intranuclear structures in continuum with the NPCs. This information could help in explaining the mechanisms, which propel the distribution of biomolecules and vectors inside the cell nuclei.To attain this aim, we used rapid cryo-immobilization to capture molecular processes of living cells with millisecond resolution. We pursued molecular imaging, including electron energy loss spectroscopy and energy dispersive x-ray spectroscopy, to reveal structures with nanometer spatial resolution. We also bioengineered single chain variable fragments to track biomolecules and transgenes' constructs.Herein, we reveal the Nuclear Routing Networks (NRNs) in the oocytes of Xenopus laevis. The NRNs originate at and extend from the tops of intranuclear baskets of the NPCs to interconnect them, while creating a complex, intra-nuclear, three-dimensional architecture. The NRNs guide the export of both tRNA, as well as the Nuclear Export Signal (NES) equipped vectors, from the nuclei. Moreover, the NRNs guide the import of both nucleoplasmin, as well as the Nuclear Localization Signals (NLS) modified transgenes' vectors, into the nuclei. The vectors equipped with these NLS and NES shuttle back and forth through the NPCs and NRNs.To summarize, we reveal the NRN, which functions as the guided distribution system in the Xenopus laevis oocytes' nuclei. We further proceed with the identification of its molecular components.

Nuclear routing networks span between nuclear pore complexes and genomic DNA to guide nucleoplasmic trafficking of biomolecules

In health and disease, biomolecules, which are involved in gene expression, recombination, or reprogramming have to traffic through the nucleoplasm, between nuclear pore complexes (NPCs) and genomic DNA (gDNA). This trafficking is guided by the recently revealed nuclear routing networks (NRNs).In this study, we aimed to investigate, if the NRNs have established associations with the genomic DNA in situ and if the NRNs have capabilities to bind the DNA de novo. Moreover, we aimed to study further, if nucleoplasmic trafficking of the histones, rRNA, and transgenes' vectors, between the NPCs and gDNA, is guided by the NRNs.We used Xenopus laevis oocytes as the model system. We engineered the transgenes' DNA vectors equipped with the SV40 LTA nuclear localization signals (NLS) and/or HIV Rev nuclear export signals (NES). We purified histones, 5S rRNA, and gDNA. We rendered all these molecules superparamagnetic and fluorescent for detection with nuclear magnetic resonance (NMR), total reflection x-ray fluorescence (TXRF), energy dispersive x-ray spectroscopy (EDXS), and electron energy loss spectroscopy (EELS).The NRNs span between the NPCs and genomic DNA. They form firm bonds with the gDNA in situ. After complete digestion of the nucleic acids with the RNases and DNases, the newly added DNA - modified with the dNTP analogs, bonds firmly to the NRNs. Moreover, the NRNs guide the trafficking of the DNA transgenes' vectors - modified with the SV40 LTA NLS, following their import into the nuclei through the NPCs. The pathway is identical to that of histones. The NRNs also guide the trafficking of the DNA transgenes' vectors, modified with the HIV Rev NES, to the NPCs, followed by their export out of the nuclei. Ribosomal RNAs follow the same pathway.To summarize, the NRNs are the structures connecting the NPCs and the gDNA. They guide the trafficking of the biomolecules between the NPCs and the gDNA.

Isolation of single, intact chromosomes from single, selected ovarian cancer cells for in situ hybridization and sequencing

The first step towards effective therapy of cancer is to reveal molecular profiles of all cell clones propelling tumor growth. The specific aim of this project was to develop a technology helping us to isolate patient's single, living cells based upon their cancer-specific, cell surface biomarkers, to reveal their molecular profiles, and to isolate, from these selected cells, intact chromosomes for in situ hybridization (FISH) and for next generation sequencing (NGS). We attained this aim, while probing the cells from the ovarian cancer patients. Ovarian cancer is the most deadly of all gynecological cancers. In most of the patients with the advanced stages of this cancer, the gene for epidermal growth factors receptor (EGFR) is mutated, as the deletion variant III, resulting in the truncated transcripts and products. From these patients, we collected cells from peritoneal fluid, blood, lymph, and biopsies. We genetically engineered fluorescent and superparamagnetic single chain variable fragments (scFvs) targeting EGFRwt and EGFRvIII. Using these scFvs, we isolated single, living ovarian cancer cells and analyzed their transcripts and products. We further genetically engineered scFv targeting dsDNA. Using these scFvs, we isolated the entire single, intact chromosomes from the selected, single ovarian cancer cells for NGS and for liquid phase FISH. This novel work-flow opens new routes not only for molecular profiling of the entire spectrum of cancer cell clones in the diagnosed patient, one cell clone at a time, but also for manufacturing targeted contrast for in vivo imaging and for designing and guiding targeted delivery of therapeutic genes in cancer therapy.

Single chain fragment variable recombinant antibody functionalized gold nanoparticles for a highly sensitive colorimetric immunoassay

In this report, the peptide linker connecting scFv V(H) and V(L) domains were genetically modified to contain different amino acids (i.e. cysteine (scFv-cys) or histidines (scFv-his)) to enable the scFv to adsorb or self-assemble onto the gold nanoparticles (NPs). The scFv-cys stabilized gold NPs were used to develop a highly sensitive colorimetric immunosensor. The scFv-cys stabilized gold NPs were characterized by UV-vis spectra, transmission electron microscope (TEM) and FTIR. After adding the antigen rabbit IgG, the solution of scFv-cys stabilized gold NPs shows obvious visible color change from deep red to light purple due to the aggregation of the gold nanoparticles. Based on the colorimetric aggregation of scFv-cys stabilized gold NPs, the immunosensor exhibits high sensitivity with a detection limit of 1.7 nM and good specificity. The good properties of the colorimetric aggregation immunosensor can be attributed to the small size of scFv and the covalent link between the scFv and gold NPs that improve the better orientation and enhance the probe density. With the advantages of speed, simplicity and specificity, the colorimetric immunoassay based on the functionalized scFv stabilized gold NPs represents a promising approach for protein analysis and clinical diagnostics.

Specific single chain variable fragment (ScFv) antibodies to angiotensin II AT(2) receptor: evaluation of the angiotensin II receptor expression in normal and tumor-bearing mouse lung

To gain insight into the mechanism by which angiotensin II type 2 receptor (AT(2)) regulates carcinogen-induced lung tumorigenesis, we have newly developed anti-AT(2) single chain variable fragment (ScFv) antibodies using a rodent phage-displayed recombinant antibody library with various peptide fragments of the receptor protein, and investigated the expression of the AT(2) receptor protein. The specificity of the antibodies was verified using AT(2) over-expressing COS-7 cells and AT(2) naturally expressing PC12W cells. In control wild type mouse lung, a stronger immunoreactivity was observed in bronchial epithelial cells. A moderate immunoreactivity was detected in pulmonary vascular walls and vascular endothelial cells. In the lungs possessing tobacco-specific nitrosamine (NNK)-induced tumors, significantly increased AT(2) and AT(1 )immunostaining was observed in adenomatous lesions. These data suggest that the increase in both receptors' expression in the alveolar epithelial cells may be accompanied with the onset of NNK-induced tumorigenesis and hence play important roles in lung tumorigenesis.

OVARIAN CANCER SUICIDE GENE THERAPY WITH GENETICALLY ENGINEERED, TRANSGENICALLY EXPRESSED, INTRACELLULAR scFv ANTIBODIES AGAINST ANTI-OXIDATIVE ENZYMES

Ovarian cancer is the leading cause of death among all gynecological cancers. Some women choose bilateral oophorectomy as means of cancer prevention. In most patients, by the time this cancer is diagnosed, it has already metastasized. Treatment involves oophorectomy followed by radiation, chemo-, and immuno-therapies. However, oopherectomy results in infertility and fails to eliminate all cancer cells. Radiation and chemotherapy cause severe side effects and may lead to genetic mutations in DNA of the ova.The ultimate goal of this project is development of a therapy which would target a therapeutic gene specific to ovarian cancer cells causing their apoptosis, but which would leave ova and other cells unharmed.Herein, we report the proof of concept for such a therapy, in which genetically engineered single chain variable fragment (scFv) antibodies against HER2/ neu, RON, and NK1R, guide the delivery of the therapeutic transgenes into the cancer cells of the ovaries. Under ovary specific promoters (OSP), the transgene expression generates the intracellular scFv antibodies, which quench cell antioxidative enzymes, thus raising levels of reactive oxygen species (ROS), inflicting oxidative stress, activating apoptotic signaling pathways, and causing cancer cell deaths.

Immobilisation of proteins by atomic clusters on surfaces

In this Opinion article, we describe a nanotechnology-based approach to immobilize and orient proteins onto surfaces using atomic clusters prepared by physical methods. This is relevant to future protein biochips where dilute arrays of protein binding sites, each designed to immobilize no more than one protein molecule, would be ideal. In the case of a surface consisting of size-selected atomic gold clusters, proteins containing free cysteine residues can chemisorb directly to the bare cluster surface, thus effecting oriented immobilisation. The selection of atomic gold clusters in the size range 1-100 atoms (<3nm in diameter) is intended to ensure that, typically, only one protein can bind directly to the cluster surface. These nanoclusters of a smaller size scale than that of the protein present minimal contact between the gold and the protein, and hence imply a reduced risk of protein denaturing compared with gold films or extended surfaces.

HER2/NEU GENE EXPRESSION PRODUCTS EVALUATED WITH SUPERPARAMAGNETIC, GENETICALLY ENGINEERED ANTIBODIES

Her2/neu is a protooncogene often amplified and overexpressed in ovary and breast cancer cells. HER2/neu receptors - HER2/neu gene expression products stimulate signal transduction pathways leading to increased cell proliferation. The level of its expression is associated with cancer malignancy. Therefore, HER2/neu is an important indicator of cancer malignancy, as well as, a target for antibody guided cancer therapies. The main objective of this work was to develop molecular probes, which would report levels of HER2/neu gene expression and anatomical distribution of its products in vivo. Magnetic resonance imaging (MRI) is particularly suitable for this endeavor, as it offers not only the best spatial resolution from all in vivo imaging modalities currently available, but also the topographic reference for location of these probes within anatomy of the human body. Superparamagnetic single chain variable fragment (scFv) antibodies targeting HER2/neu receptors were genetically engineered. They warranted high labeling specificity and affinity revealed with EDXSI, as well as, induced significant changes in relaxivity detected with NMR. This study demonstrated a proof of concept for using superparamagnetic scFvs in diagnostic evaluation of levels of gene expression products with NMR and MRI for planning receptor targeted therapies.

Integrated nanoparticle-biomolecule hybrid systems: synthesis, properties, and applications

Nanomaterials, such as metal or semiconductor nanoparticles and nanorods, exhibit similar dimensions to those of biomolecules, such as proteins (enzymes, antigens, antibodies) or DNA. The integration of nanoparticles, which exhibit unique electronic, photonic, and catalytic properties, with biomaterials, which display unique recognition, catalytic, and inhibition properties, yields novel hybrid nanobiomaterials of synergetic properties and functions. This review describes recent advances in the synthesis of biomolecule-nanoparticle/nanorod hybrid systems and the application of such assemblies in the generation of 2D and 3D ordered structures in solutions and on surfaces. Particular emphasis is directed to the use of biomolecule-nanoparticle (metallic or semiconductive) assemblies for bioanalytical applications and for the fabrication of bioelectronic devices.

Myocardial biopsy findings and gadolinium enhanced cardiovascular magnetic resonance in dilated cardiomyopathy

BACKGROUND

In some patients suffering from dilated cardiomyopathy (DCM) magnetic resonance imaging (MRI) shows late gadolinium enhancement with variable distribution. Myocardial biopsies in DCM reveal a chronic myocardial inflammatory process in almost 50% and myocardial persistence of adenoviral or enteroviral genome in about 15% of the patients.

AIMS

We prospectively investigated whether the pattern of late gadolinium enhancement correlates with myocardial biopsy findings.

METHODS AND RESULTS

42 patients with DCM and 42 control subjects underwent contrast MRI. In the DCM group, endomyocardial biopsies were performed and evaluated for inflammation and viral genome. None of the control subjects showed late gadolinium enhancement whereas in 29 DCM patients (69%) gadolinium enhancement was detectable (p<0.001). 21 of the DCM patients (50%) showed midwall septal enhancement, 7 patients (17%) showed a patchy distribution of hyperenhancement and 1 patient (2%) showed enhancement typical for ischemic heart disease. In myocardial biopsy analysis, 2 patients (5%) showed persistence of viral genome, 18 patients (43%) showed inflammation and in 22 patients (52%) neither virus nor inflammation was detected. The pattern of late gadolinium enhancement and myocardial biopsy findings were not significantly correlated (p = 0.854).

CONCLUSION

MRI as a non-invasive technique cannot replace myocardial biopsy for the differential diagnosis of DCM.

Expression of an anti-CD33 single-chain antibody by Pichia pastoris

CD33 is a cell surface glycoprotein expressed on cells of myelomonocytic lineage, leukaemic cells, but not haematopoietic stem cells. By virtue of its expression pattern, CD33 has become a popular target for new immunotherapeutic approaches to treat acute myeloid leukaemia. The methylotrophic yeast Pichia pastoris strain KM71H was used to produce an anti-CD33 single chain variable fragment (scFv), with the intention of conjugation to a radioisotope, for therapeutic use. To direct secreted expression of the anti-CD33-scFv the alpha-mating factor secretory signal sequence (alpha-MF) was used, with constructs containing a complete (CS) and incomplete (INCS) cleavage site to accommodate the potential outcomes of dibasic endopeptidase, Kex2, and dipeptidyl amino peptidase, Ste13, processing. The anti-CD33-scFv was expressed in BMMY cultures using both constructs, with a final yield of 48 mg/l (CS) and 11 mg/l (INCS). N-terminal sequencing showed that the CS-scFv had not been cleaved by Ste13, leaving amino acids EAEA at the N-terminus. The INCS-scFv construct produced a mixture of 50% authentic scFv and 50% with 11 amino acids from the alpha-MF remaining at the N-terminus. Despite the aberrations in alpha-MF processing, the anti-CD33-scFv's produced from both constructs were found to be functional. Flow cytometry and Biacore analysis demonstrated binding to target antigen CD33 on the surface of human leukaemic cell line HL-60, and to recombinant soluble CD33 respectively.

Organization of chromatin in the interphase mammalian cell

The use of imaging techniques has become an essential tool in cell biology. In particular, advances in fluorescence microscopy and conventional transmission electron microscopy have had a major impact on our understanding of chromatin structure and function. In this review we attempt to chart the conceptual evolution of models describing the organization and function of chromatin in higher eukaryotic cells, in parallel with the advances in light and electron microscopy over the past 50 years. In the last decade alone, the application of energy filtered transmission electron microscopy (EFTEM), also referred to as electron spectroscopic imaging (ESI), has provided many new insights into the organization of chromatin in the interphase nucleus. Based on ESI imaging of chromatin in situ, we propose a 'lattice' model for the organization of chromatin in interphase cells. In this model, the chromatin fibers of 10 and 30nm diameter observed by ESI, produce a meshwork that accommodates an extensive and distributed interchromosomal (IC) space devoid of chromatin. The functional implications of this model for nuclear activity are discussed.

A survey of the year 2002 commercial optical biosensor literature

We have compiled 819 articles published in the year 2002 that involved commercial optical biosensor technology. The literature demonstrates that the technology's application continues to increase as biosensors are contributing to diverse scientific fields and are used to examine interactions ranging in size from small molecules to whole cells. Also, the variety of available commercial biosensor platforms is increasing and the expertise of users is improving. In this review, we use the literature to focus on the basic types of biosensor experiments, including kinetics, equilibrium analysis, solution competition, active concentration determination and screening. In addition, using examples of particularly well-performed analyses, we illustrate the high information content available in the primary response data and emphasize the impact of including figures in publications to support the results of biosensor analyses.

Recombinatorial cloning using heterologous lox sites

Recombination systems based on lambda and Cre/loxP have been described to facilitate gene transfer from one vector to another in a high-throughput fashion, avoiding the bottlenecks associated with traditional cloning. However, no system described to date is suitable for the cloning of affinity reagents selected from display libraries, which requires that the recombination signals flanking the affinity reagent are translated with a minimum impact on functionality. As affinity reagents will be essential tools in the functional characterization of proteomes, and display technologies represent the most effective means to generate such affinity reagents on a genomic scale, we developed a Cre/loxP-based system, using mutually exclusive heterologous loxP sites placed 5' (Lox 2372) and 3' (Lox WT) of an affinity reagent (scFv). The translated lox sites have minimal impact on scFv expression or functionality, and, in association with a conditionally lethal gene (SacB) permit efficient, high-fidelity transfer to destination vectors. This approach will considerably facilitate the high-throughput downstream use of affinity reagents selected by display technologies, as well as being widely applicable to general recombinatorial cloning for genomic purposes.

Same serial section correlative light and energy-filtered transmission electron microscopy

Correlative imaging of a specific cell with both the light microscope and the electron microscope has proved to be a difficult task, requiring enormous amounts of patience and technical skill. We describe a technique with a high rate of success, which can be used to identify a particular cell in the light microscope and then to embed and thin-section it for electron microscopy. The technique also includes a method to obtain many uninterrupted, thin serial sections for imaging by conventional or energy-filtered transmission electron microscopy, to obtain images for 3D analysis of detail at the suborganelle level.