Skipped Aganglionic Lengthening Transposition (SALT) is highly effective to achieve enteral autonomy in selected patients with intestinal failure secondary to total intestinal aganglionosis

BACKGROUND

Intestinal Failure, parenteral nutrition (PN) dependence, and subsequent liver disease are the most challenging and life-threatening complications of short bowel syndrome experienced by patients with total intestinal aganglionosis. Skipped Aganglionic Lengthening Transposition (SALT) showed to be a promising procedure to overcome such problems. We herein report the results of two patients who underwent SALT at the Umberto Bosio Center for Digestive Diseases.

PATIENTS AND METHODS

Between November 2019 and July 2022, 2 patients with total intestinal aganglionosis underwent SALT as autologous intestinal lengthening procedure. Perioperative data and long-term outcomes are reported. Patient #1-A 18 month-old male (PN dependant) with 30 cm of ganglionated bowel at birth experienced a 35% increase of intestinal length after SALT (from 43 to 58 cm) thanks to three 5 cm interposed aganglionic loops. Postoperative course was uneventful and he was totally weaned by PN after 28 months postoperatively. He is without PN only receiving enteric feeding 53 months after the procedure. Patient #2-A 11 year-old female (PN dependant) with 100 cm of ganglionated jejunum underwent SALT at 11 years and experienced a 19% increase of bowel length thanks to four 5 to 7 cm interposed aganglionic loops. Postoperatively she required excision of two out of the four loops due to severe strictures and inadequate perfusion with a subsequent overall 10% increase of length after SALT. Of note, she improved significantly with a progressive reduction of PN that has been stopped after 18 months.

CONCLUSION

Skipped aganglionic lengthening transposition (SALT) seems to be very effective in improving nutrients absorption in patients with total intestinal aganglionosis by increasing absorptive bowel surface and decelerating intestinal flow for a longer and more effective contact of enteric material with ileal mucosa. Provided these impressive results are confirmed in the very long-term, SALT could become a valid alternative for the treatment of patients with total intestinal aganglionosis carrying at birth at least 20 to 30 cm of ganglionated jejunum.

Delayed diagnosis in Hirschsprung disease

INTRODUCTION

Diagnostic delay in Hirschsprung disease is uncommon. Different definitions have been proposed but that of a diagnosis achieved after 12 months of age seems to be the most reliable and resorted to. Some authors reported a worse outcome in case of delay. Our study aims at providing the most relevant features of a series of patients who received a delayed diagnosis of Hirschsprung disease.

MATERIALS AND METHODS

All consecutive patients admitted to our Center with a delayed diagnosis of Hirschsprung diseases between January 2017 and July 2023 have been retrospectively enrolled. Demographic data, phenotype, genotype, surgical complications, and outcome were assessed and compared to those of literature. A number of variables were also compared to those of a series of patients admitted during the same study period without a delayed diagnosis.

RESULTS

A total of 45 patients were included (16.4% out of a series of 346 patients with data regarding age at diagnosis). Male to female ratio was 3.1:1. Median age at diagnosis was 41 months with a wide variation (range between 17 months and 58 years). All patients but 2 suffered from classic rectosigmoid aganglionosis. Normal meconium passage (58%) was reported in a significantly higher number of patients compared to what observed in a series without diagnostic delay (p = 0.0140). All other variables (associated anomalies, preoperative enterocolitis, complications, and functional outcome) proved not to have statistically significant differences compared to a series of patients without a diagnostic delay.

CONCLUSIONS

The results of our study underline that a significant percentage of patients are basically missed in the neonatal period mostly due to mild symptoms. Overall outcome does not differ from that of patients without diagnostic delay. Nonetheless, we underline the importance of a throughout investigation of all patients with meconium delay/failure and that of adopting a low threshold for performing rectal suction biopsies in constipated children to avoid misdiagnosis to serve the best for our patients.

Immunogenicity of Escherichia coli Outer Membrane Vesicles: Elucidation of Humoral Responses against OMV-Associated Antigens

Outer membrane vesicles (OMVs) produced by Gram-negative bacteria have emerged as a novel and flexible vaccine platform. OMVs can be decorated with foreign antigens and carry potent immunostimulatory components. Therefore, after their purification from the culture supernatant, they are ready to be formulated for vaccine use. It has been extensively demonstrated that immunization with engineered OMVs can elicit excellent antibody responses against the heterologous antigens. However, the definition of the conditions necessary to reach the optimal antibody titers still needs to be investigated. Here, we defined the protein concentrations required to induce antigen-specific antibodies, and the amount of antigen and OMVs necessary and sufficient to elicit saturating levels of antigen-specific antibodies. Since not all antigens can be expressed in OMVs, we also investigated the effectiveness of vaccines in which OMVs and purified antigens are mixed together without using any procedure for their physical association. Our data show that in most of the cases OMV-antigen mixtures are very effective in eliciting antigen-specific antibodies. This is probably due to the capacity of OMVs to "absorb" antigens, establishing sufficiently stable interactions that allow antigen-OMV co-presentation to the same antigen presenting cell. In those cases when antigen-OMV interaction is not sufficiently stable, the addition of alum to the formulation guarantees the elicitation of high titers of antigen-specific antibodies.

A unicentric cross-sectional observational study on chronic intestinal inflammation in total colonic aganglionosis: beware of an underestimated condition

BACKGROUND

Inflammatory Bowel Diseases (IBD) are known to occur in association with Hirschsprung disease (HSCR). Most of cases are represented by Crohn Disease (CD) occurring in patients with Total Colonic Aganglionosis (TCSA) with an estimated prevalence of around 2%. Based on these considerations and on a number of provisional data belonging to our Center for Digestive Diseases, we developed a unicentric cross-sectional observational study aimed at describing phenotype, genotype, pathology and metagenomics of all patients with TCSA and Crohn-like lesions.

RESULTS

Out of a series of 62 eligible TCSA patients, 48 fulfilled inclusion criteria and were enrolled in the study. Ten patients did not complete the study due to non-compliance or withdrawal of consent and were subsequently dropped out. A total of 38 patients completed the study. All patients were tested for chronic intestinal inflammation by a combination of fecal calprotectine (FC) or occult fecal blood (OFB) and underwent fecal metagenomics. Nineteen (50%) tested positive for FC, OFB, or both and subsequently underwent retrograde ileoscopy. Fourteen patients (36.8%) presented Crohn-like lesions, occurring after a median of 11.5 years after surgery (range 8 months - 21.5 years). No statistically significant differences regarding demographic, phenotype and genotype were observed comparing patients with and without lesions, except for need for blood transfusion that was more frequent in those with lesions. Faecal microbiome of patients with lesions (not that of caregivers) was less biodiverse and characterized by a reduction of Bacteroidetes, and an overabundance of Proteobacteria. FC tested negative in 3/14 patients with lesions (21%).

CONCLUSIONS

Our study demonstrated an impressive 10-folds higher incidence of chronic inflammation in TCSA. Up to 50% of patients may develop IBD-like lesions postoperatively. Nonetheless, we failed in identifying specific risk factors to be used to implement prevention strategies. Based on the results of our study, we suggest screening all TCSA patients with retrograde ileoscopy regardless of FC/OFB values. The frequency of endoscopic assessments and the role of FC/OFB screening in prompting endoscopy is yet to be determined.

Bacterial Outer Membrane Vesicles as a Platform for the Development of a Broadly Protective Human Papillomavirus Vaccine Based on the Minor Capsid Protein L2

Human papillomaviruses (HPVs) are a large family of viruses with a capsid composed of the L1 and L2 proteins, which bind to receptors of the basal epithelial cells and promote virus entry. The majority of sexually active people become exposed to HPV and the virus is the most common cause of cervical cancer. Vaccines are available based on the L1 protein, which self-assembles and forms virus-like particles (VLPs) when expressed in yeast and insect cells. Although very effective, these vaccines are HPV type-restricted and their costs limit broad vaccination campaigns. Recently, vaccine candidates based on the conserved L2 epitope from serotypes 16, 18, 31, 33, 35, 6, 51, and 59 were shown to elicit broadly neutralizing anti-HPV antibodies. In this study, we tested whether E. coli outer membrane vesicles (OMVs) could be successfully decorated with L2 polytopes and whether the engineered OMVs could induce neutralizing antibodies. OMVs represent an attractive vaccine platform owing to their intrinsic adjuvanticity and their low production costs. We show that strings of L2 epitopes could be efficiently expressed on the surface of the OMVs and a polypeptide composed of the L2 epitopes from serotypes 18, 33, 35, and 59 provided a broad cross-protective activity against a large panel of HPV serotypes as determined using pseudovirus neutralization assay. Considering the simplicity of the OMV production process, our work provides a highly effective and inexpensive solution to produce universal anti-HPV vaccines.

Immunogenicity and Pre-Clinical Efficacy of an OMV-Based SARS-CoV-2 Vaccine

The vaccination campaign against SARS-CoV-2 relies on the world-wide availability of effective vaccines, with a potential need of 20 billion vaccine doses to fully vaccinate the world population. To reach this goal, the manufacturing and logistic processes should be affordable to all countries, irrespective of economical and climatic conditions. Outer membrane vesicles (OMVs) are bacterial-derived vesicles that can be engineered to incorporate heterologous antigens. Given the inherent adjuvanticity, such modified OMVs can be used as vaccines to induce potent immune responses against the associated proteins. Here, we show that OMVs engineered to incorporate peptides derived from the receptor binding motif (RBM) of the spike protein from SARS-CoV-2 elicit an effective immune response in vaccinated mice, resulting in the production of neutralizing antibodies (nAbs) with a titre higher than 1:300. The immunity induced by the vaccine is sufficient to protect the animals from intranasal challenge with SARS-CoV-2, preventing both virus replication in the lungs and the pathology associated with virus infection. Furthermore, we show that OMVs can be effectively decorated with the RBM of the Omicron BA.1 variant and that such engineered OMVs induce nAbs against Omicron BA.1 and BA.5, as measured using the pseudovirus neutralization infectivity assay. Importantly, we show that the RBM438-509 ancestral-OMVs elicited antibodies which efficiently neutralize in vitro both the homologous ancestral strain, the Omicron BA.1 and BA.5 variants with a neutralization titre ranging from 1:100 to 1:1500, suggesting its potential use as a vaccine targeting diverse SARS-CoV-2 variants. Altogether, given the convenience associated with the ease of engineering, production and distribution, our results demonstrate that OMV-based SARS-CoV-2 vaccines can be a crucial addition to the vaccines currently available.

Anti-Tumor Efficacy of In Situ Vaccination Using Bacterial Outer Membrane Vesicles

In situ vaccination (ISV) is a promising cancer immunotherapy strategy that consists of the intratumoral administration of immunostimulatory molecules (adjuvants). The rationale is that tumor antigens are abundant at the tumor site, and therefore, to elicit an effective anti-tumor immune response, all that is needed is an adjuvant, which can turn the immunosuppressive environment into an immunologically active one. Bacterial outer membrane vesicles (OMVs) are potent adjuvants since they contain several microbe-associated molecular patterns (MAMPs) naturally present in the outer membrane and in the periplasmic space of Gram-negative bacteria. Therefore, they appear particularly indicted for ISV. In this work, we first show that the OMVs from E. coli BL21(DE3)Δ60 strain promote a strong anti-tumor activity when intratumorally injected into the tumors of three different mouse models. Tumor inhibition correlates with a rapid infiltration of DCs and NK cells. We also show that the addition of neo-epitopes to OMVs synergizes with the vesicle adjuvanticity, as judged by a two-tumor mouse model. Overall, our data support the use of the OMVs in ISV and indicate that ISV efficacy can benefit from the addition of properly selected tumor-specific neo-antigens.

Immunogenicity and pre-clinical efficacy of an OMV-based SARS-CoV-2 vaccine

The vaccination campaign against SARS-CoV-2 relies on the world-wide availability of effective vaccines, with a potential need of 20 billion vaccine doses to fully vaccinate the world population. To reach this goal, the manufacturing and logistic processes should be affordable to all countries, irrespectively of economical and climatic conditions. Outer membrane vesicles (OMV) are bacterial-derived vesicles that can be engineered to incorporate heterologous antigens. Given the inherent adjuvanticity, such modified OMV can be used as vaccine to induce potent immune responses against the associated protein. Here we show that OMVs engineered to incorporate peptides derived from the receptor binding motif (RBM) of the spike protein from SARS-CoV-2 elicit an effective immune response in vaccinated mice, resulting in the production of neutralizing antibodies (nAbs). The immunity induced by the vaccine is sufficient to protect the animals from intranasal challenge with SARS-CoV-2, preventing both virus replication in the lungs and the pathology associated with virus infection. Furthermore, we show that OMVs can be effectively decorated with the RBM of the Omicron BA.1 variant and that such engineered OMVs induced nAbs against Omicron BA.1 and BA.5, as judged by pseudovirus infectivity assay. Importantly, we show that the RBM438-509 ancestral-OMVs elicited antibodies which efficiently neutralized in vitro both the homologous ancestral strain, the Omicron BA.1 and BA.5 variants, suggesting its potential use as a pan SARS-CoV-2 vaccine. Altogether, given the convenience associated with ease of engineering, production and distribution, our results demonstrate that OMV-based SARS-CoV-2 vaccines can be a crucial addition to the vaccines currently available.

Outer Membrane Vesicles From The Gut Microbiome Contribute to Tumor Immunity by Eliciting Cross-Reactive T Cells

A growing body of evidence supports the notion that the gut microbiome plays an important role in cancer immunity. However, the underpinning mechanisms remain to be fully elucidated. One attractive hypothesis envisages that among the T cells elicited by the plethora of microbiome proteins a few exist that incidentally recognize neo-epitopes arising from cancer mutations (“molecular mimicry (MM)” hypothesis). To support MM, the human probiotic Escherichia coli Nissle was engineered with the SIINFEKL epitope (OVA-E.coli Nissle) and orally administered to C57BL/6 mice. The treatment with OVA-E.coli Nissle, but not with wild type E. coli Nissle, induced OVA-specific CD8⁺ T cells and inhibited the growth of tumors in mice challenged with B16F10 melanoma cells expressing OVA. The microbiome shotgun sequencing and the sequencing of TCRs from T cells recovered from both lamina propria and tumors provide evidence that the main mechanism of tumor inhibition is mediated by the elicitation at the intestinal site of cross-reacting T cells, which subsequently reach the tumor environment. Importantly, the administration of Outer Membrane Vesicles (OMVs) from engineered E. coli Nissle, as well as from E. coli BL21(DE3)ΔompA, carrying cancer-specific T cell epitopes also elicited epitope-specific T cells in the intestine and inhibited tumor growth. Overall, our data strengthen the important role of MM in tumor immunity and assign a novel function of OMVs in host-pathogen interaction. Moreover, our results pave the way to the exploitation of probiotics and OMVs engineered with tumor specific-antigens as personalized mucosal cancer vaccines.

Multi-Antigen Outer Membrane Vesicle Engineering to Develop Polyvalent Vaccines: The Staphylococcus aureus Case

Modification of surface antigens and differential expression of virulence factors are frequent strategies pathogens adopt to escape the host immune system. These escape mechanisms make pathogens a "moving target" for our immune system and represent a challenge for the development of vaccines, which require more than one antigen to be efficacious. Therefore, the availability of strategies, which simplify vaccine design, is highly desirable. Bacterial Outer Membrane Vesicles (OMVs) are a promising vaccine platform for their built-in adjuvanticity, ease of purification and flexibility to be engineered with foreign proteins. However, data on if and how OMVs can be engineered with multiple antigens is limited. In this work, we report a multi-antigen expression strategy based on the co-expression of two chimeras, each constituted by head-to-tail fusions of immunogenic proteins, in the same OMV-producing strain. We tested the strategy to develop a vaccine against Staphylococcus aureus, a Gram-positive human pathogen responsible for a large number of community and hospital-acquired diseases. Here we describe an OMV-based vaccine in which four S. aureus virulent factors, ClfA_Y338A, LukE, SpA_KKAA and Hla_H35L have been co-expressed in the same OMVs (CLSH-OMVs_Δ60). The vaccine elicited antigen-specific antibodies with functional activity, as judged by their capacity to promote opsonophagocytosis and to inhibit Hla-mediated hemolysis, LukED-mediated leukocyte killing, and ClfA-mediated S. aureus binding to fibrinogen. Mice vaccinated with CLSH-OMVs_Δ60 were robustly protected from S. aureus challenge in the skin, sepsis and kidney abscess models. This study not only describes a generalized approach to develop easy-to-produce and inexpensive multi-component vaccines, but also proposes a new tetravalent vaccine candidate ready to move to development.

Commensal Bifidobacterium Strains Enhance the Efficacy of Neo-Epitope Based Cancer Vaccines

A large body of data both in animals and humans demonstrates that the gut microbiome plays a fundamental role in cancer immunity and in determining the efficacy of cancer immunotherapy. In this work, we have investigated whether and to what extent the gut microbiome can influence the antitumor activity of neo-epitope-based cancer vaccines in a BALB/c-CT26 cancer mouse model. Similarly to that observed in the C57BL/6-B16 model, Bifidobacterium administration per se has a beneficial effect on CT26 tumor inhibition. Furthermore, the combination of Bifidobacterium administration and vaccination resulted in a protection which was superior to vaccination alone and to Bifidobacterium administration alone, and correlated with an increase in the frequency of vaccine-specific T cells. The gut microbiome analysis by 16S rRNA gene sequencing and shotgun metagenomics showed that tumor challenge rapidly altered the microbiome population, with Muribaculaceae being enriched and Lachnospiraceae being reduced. Over time, the population of Muribaculaceae progressively reduced while the Lachnospiraceae population increased—a trend that appeared to be retarded by the oral administration of Bifidobacterium. Interestingly, in some Bacteroidales, Prevotella and Muribaculacee species we identified sequences highly homologous to immunogenic neo-epitopes of CT26 cells, supporting the possible role of “molecular mimicry” in anticancer immunity. Our data strengthen the importance of the microbiome in cancer immunity and suggests a microbiome-based strategy to potentiate neo-epitope-based cancer vaccines.

Proteome-minimized outer membrane vesicles from Escherichia coli as a generalized vaccine platform

Because of their potent adjuvanticity, ease of manipulation and simplicity of production Gram‐negative Outer Membrane Vesicles OMVs have the potential to become a highly effective vaccine platform. However, some optimization is required, including the reduction of the number of endogenous proteins, the increase of the loading capacity with respect to heterologous antigens, the enhancement of productivity in terms of number of vesicles per culture volume. In this work we describe the use of Synthetic Biology to create Escherichia coli BL21(DE3)Δ60, a strain releasing OMVs (OMVs_Δ60) deprived of 59 endogenous proteins. The strain produces large quantities of vesicles (> 40 mg/L under laboratory conditions), which can accommodate recombinant proteins to a level ranging from 5% to 30% of total OMV proteins. Moreover, also thanks to the absence of immune responses toward the inactivated endogenous proteins, OMVs_Δ60 decorated with heterologous antigens/epitopes elicit elevated antigens/epitopes‐specific antibody titers and high frequencies of epitope‐specific IFN‐γ‐producing CD8⁺ T cells. Altogether, we believe that E. coli BL21(DE3)Δ60 have the potential to become a workhorse factory for novel OMV‐based vaccines.

Vaccination With a FAT1-Derived B Cell Epitope Combined With Tumor-Specific B and T Cell Epitopes Elicits Additive Protection in Cancer Mouse Models

Human FAT1 is overexpressed on the surface of most colorectal cancers (CRCs) and in particular a 25 amino acid sequence (D8) present in one of the 34 cadherin extracellular repeats carries the epitope recognized by mAb198.3, a monoclonal antibody which partially protects mice from the challenge with human CRC cell lines in xenograft mouse models. Here we present data in immune competent mice demonstrating the potential of the D8-FAT1 epitope as CRC cancer vaccine. We first demonstrated that the mouse homolog of D8-FAT1 (mD8-FAT1) is also expressed on the surface of CT26 and B16F10 murine cell lines. We then engineered bacterial outer membranes vesicles (OMVs) with mD8-FAT1 and we showed that immunization of BALB/c and C57bl6 mice with engineered OMVs elicited anti-mD8-FAT1 antibodies and partially protected mice from the challenge against CT26 and EGFRvIII-B16F10 cell lines, respectively. We also show that when combined with OMVs decorated with the EGFRvIII B cell epitope or with OMVs carrying five tumor-specific CD4+ T cells neoepitopes, mD8-FAT1 OMVs conferred robust protection against tumor challenge in C57bl6 and BALB/c mice, respectively. Considering that FAT1 is overexpressed in both KRAS⁺ and KRAS⁻ CRCs, these data support the development of anti-CRC cancer vaccines in which the D8-FAT1 epitope is used in combination with other CRC-specific antigens, including mutation-derived neoepitopes.

Synergistic Protective Activity of Tumor-Specific Epitopes Engineered in Bacterial Outer Membrane Vesicles

Introduction

Bacterial outer membrane vesicles (OMVs) are naturally produced by all Gram-negative bacteria and, thanks to their plasticity and unique adjuvanticity, are emerging as an attractive vaccine platform. To test the applicability of OMVs in cancer immunotherapy, we decorated them with either one or two protective epitopes present in the B16F10EGFRvIII cell line and tested the protective activity of OMV immunization in C57BL/6 mice challenged with B16F10EGFRvIII.

Materials and methods

The 14 amino acid B cell epitope of human epidermal growth factor receptor variant III (EGFRvIII) and the mutation-derived CD4+ T cell neo-epitope of kif18b gene (B16-M30) were used to decorate OMVs either alone or in combination. C57BL/6 were immunized with the OMVs and then challenged with B16F10EGFRvIII cells. Immunogenicity and protective activity was followed by measuring anti-EGFRvIII antibodies, M30-specific T cells, tumor-infiltrating cell population, and tumor growth.

Results

Immunization with engineered EGFRvIII-OMVs induced a strong inhibition of tumor growth after B16F10EGFRvIII challenge. Furthermore, mice immunized with engineered OMVs carrying both EGFRvIII and M30 epitopes were completely protected from tumor challenge. Immunization was accompanied by induction of high anti-EGFRvIII antibody titers, M30-specific T cells, and infiltration of CD4+ and CD8+ T cells at the tumor site.

Conclusion

OMVs can be decorated with tumor antigens and can elicit antigen-specific, protective antitumor responses in immunocompetent mice. The synergistic protective activity of multiple epitopes simultaneously administered with OMVs makes the OMV platform particularly attractive for cancer immunotherapy.

TCTN2: a novel tumor marker with oncogenic properties

Tectonic family member 2 (TCTN2) encodes a transmembrane protein that belongs to the tectonic family, which is involved in ciliary functions. Previous studies have demonstrated the role of tectonics in regulating a variety of signaling pathways at the transition zone of cilia. However, the role of tectonics in cancer is still unclear. Here we identify that TCTN2 is overexpressed in colorectal, lung and ovary cancers. We show that different cancer cell lines express the protein that localizes at the plasma membrane, facing the intracellular milieu. TCTN2 over-expression in cancer cells resulted in an increased ability to form colonies in an anchorage independent way. On the other hand, downregulation of TCTN2 using targeted epigenetic editing in cancer cells significantly reduced colony formation, cell invasiveness, increased apoptosis and impaired assembly of primary cilia. Taken together, our results indicate that TCTN2 acts as an oncogene, making it an interesting cancer-associated protein and a potential candidate for therapeutic applications.

Some Gram-negative Lipoproteins Keep Their Surface Topology When Transplanted from One Species to Another and Deliver Foreign Polypeptides to the Bacterial Surface

In Gram-negative bacteria, outer membrane-associated lipoproteins can either face the periplasm or protrude out of the bacterial surface. The mechanisms involved in lipoprotein transport through the outer membrane are not fully elucidated. Some lipoproteins reach the surface by using species-specific transport machinery. By contrast, a still poorly characterized group of lipoproteins appears to always cross the outer membrane, even when transplanted from one organism to another. To investigate such lipoproteins, we tested the expression and compartmentalization in E. coli of three surface-exposed lipoproteins, two from Neisseria meningitidis (Nm-fHbp and NHBA) and one from Aggregatibacter actinomycetemcomitans (Aa-fHbp). We found that all three lipoproteins were lipidated and compartmentalized in the E. coli outer membrane and in outer membrane vesicles. Furthermore, fluorescent antibody cell sorting analysis, proteolytic surface shaving, and confocal microscopy revealed that all three proteins were also exposed on the surface of the outer membrane. Removal or substitution of the first four amino acids following the lipidated cysteine residue and extensive deletions of the C-terminal regions in Nm-fHbp did not prevent the protein from reaching the surface of the outer membrane. Heterologous polypeptides, fused to the C termini of Nm-fHbp and NHBA, were efficiently transported to the E. coli cell surface and compartmentalized in outer membrane vesicles, demonstrating that these lipoproteins can be exploited in biotechnological applications requiring Gram-negative bacterial surface display of foreign polypeptides.

Large scale validation of an efficient CRISPR/Cas-based multi gene editing protocol in Escherichia coli

BACKGROUND

The exploitation of the CRISPR/Cas9 machinery coupled to lambda (λ) recombinase-mediated homologous recombination (recombineering) is becoming the method of choice for genome editing in E. coli. First proposed by Jiang and co-workers, the strategy has been subsequently fine-tuned by several authors who demonstrated, by using few selected loci, that the efficiency of mutagenesis (number of mutant colonies over total number of colonies analyzed) can be extremely high (up to 100%). However, from published data it is difficult to appreciate the robustness of the technology, defined as the number of successfully mutated loci over the total number of targeted loci. This information is particularly relevant in high-throughput genome editing, where repetition of experiments to rescue missing mutants would be impractical. This work describes a "brute force" validation activity, which culminated in the definition of a robust, simple and rapid protocol for single or multiple gene deletions.

RESULTS

We first set up our own version of the CRISPR/Cas9 protocol and then we evaluated the mutagenesis efficiency by changing different parameters including sequence of guide RNAs, length and concentration of donor DNAs, and use of single stranded and double stranded donor DNAs. We then validated the optimized conditions targeting 78 "dispensable" genes. This work led to the definition of a protocol, featuring the use of double stranded synthetic donor DNAs, which guarantees mutagenesis efficiencies consistently higher than 10% and a robustness of 100%. The procedure can be applied also for simultaneous gene deletions.

CONCLUSIONS

This work defines for the first time the robustness of a CRISPR/Cas9-based protocol based on a large sample size. Since the technical solutions here proposed can be applied to other similar procedures, the data could be of general interest for the scientific community working on bacterial genome editing and, in particular, for those involved in synthetic biology projects requiring high throughput procedures.

Abstract 3800: Novel targets and monoclonal antibodies for cancer therapy

The identification of markers targetable by specific mAbs represents a high medical need in cancer therapy. Our objective is to discover novel tumor-associated proteins showing promise as targets for monoclonal antibody (mAb) therapy, and to generate and validate highly specific mAbs for therapeutic applications. The approach we used to discover novel tumor markers is based on a high through-put immune-histochemical (IHC) screening of tumor and normal tissues using collections of murine polyclonal and mAbs raised against recombinant human proteins. In the course of such analysis, we discovered and validated different surface exposed proteins over-expressed in one or more cancers. Here, we report a surface exposed protein mainly over-expressed in ovary and breast cancers. Interestingly, the protein is highly expressed in high grade breast cancers. Approximately 40% of cancers in which the protein is over-expressed belong to the triple negative subtype. In line with IHC data, an expression profile analysis in different cells lines showed that this protein is expressed in ovarian and breast cancer cell lines. In breast cell lines, high expression was found in triple negative cells positive to the androgen receptor. Gene silencing experiments combined to phenotypic analysis, showed that loss of protein expression significantly reduces cell proliferation and invasiveness. Several mAbs able to recognize the target protein on the surface of breast and ovary cancer cell lines have been selected and validated in a number of immunoassays. The specificity of the mAb binding was confirmed by gene silencing and competition assays with peptides encompassing the mAb epitopes. Specific mAbs able to detect the protein in cancer cells in IHC are under validation. These antibodies show limited reactivity on normal human tissues and are negative on PBMC from normal donors. Moreover, these mAbs are efficiently internalized by cancer cells, suggesting that they are amenable to the development of Antibody-Drug-Conjugate. Finally, they efficiently recognize the macaca protein ortholog, thus facilitating future safety studies in non-human primates. Overall, results so far accumulated highlight the potential of this novel tumor-associated protein and available mAbs for the development of targeted therapy against ovarian cancer and triple negative breast cancer. Other promising targets and related monoclonal antibodies will be described during the meeting.

Citation Format: Matteo Parri, Susanna Campagnoli, Alberto Grandi, Elisa De Camilli, Aurelien Lacombe, Boquan Jin, Serenella Eppenberger-Castori, Giuseppe Viale, Luigi Terracciano, Piero Pileri, Renata Maria Grifantini. Novel targets and monoclonal antibodies for cancer therapy. [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 3800.

Abstract 4870: A novel potential target for cancer immunotherapy

Suppression of the host's immune system plays a major role in cancer progression. The tumor microenvironment (TME) not only plays a pivotal role during cancer progression and metastasis but also has profound effects on therapeutic efficacy. Immune checkpoint therapy, which targets regulatory pathways in T cells to enhance antitumor immune responses, has led to important clinical advances and provided a new weapon against cancer. This therapy has elicited durable clinical responses and, in a fraction of patients, long-term remissions. Several immune checkpoint inhibitors have been approved by the Food and Drug Administration (FDA), whose therapeutic effect is due to blocking the activity of proteins expressed in T lymphocytes (CTLA4, PD-1) and the interaction with surface protein expressed on tumor cells (PD-L1 and PD-L2).

In our recent research activities we have identified 89 tumor-associated proteins by systematic immunohistochemistry analysis of tissue microarray (TMA) representing breast, colon, lung ovary and prostate cancer by using a large collection of polyclonal antibodies (approximately 1600) raised against membrane-associated and secreted proteins only marginally characterized. Among them, an interesting protein, which decorated the plasma membrane of breast cancer cells, was selected. This protein has been described to interact with the CD270/BTLA/CD160 pathway that regulates T-cell activation. It has also the capability to interfere with T-cell mediated allo-responses. Our characterization data showed that the protein is localized on the surface of several cancer cell lines. Moreover, it has the ability to stimulate cytokine production and secretion in PBMC from healthy donors. Several monoclonal antibodies have been generated in our lab against this protein and selected for the ability to bind the surface of cancer cells. Moreover, the ability of these monoclonal antibodies to interfere with the immune cells activity and to interfere with tumor growth in animal models is under evaluation. Results will be provided during the meeting.

The currently approved therapeutic targets regimens for triple negative breast cancer and ovarian cancer have limited efficacy. Therefore, the identification of other tumor-associated proteins targetable by specific mAbs is essential to improve patient survival.

Citation Format: Susanna Campagnoli, Matteo Parri, Alberto Grandi, Elisa De Camilli, Giuseppe Viale, Renata Maria Grifantini, Piero Pileri. A novel potential target for cancer immunotherapy. [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 4870.

Vaccinology: The art of putting together the right ingredients

Historically vaccines were produced using whole attenuated or killed pathogens and still a large proportion of current vaccines utilizes such procedure. However, for safety and quality reasons the development of novel vaccines is preferentially based on the selection and use of specific pathogen components which alone are capable of eliciting protective immune responses against the pathogens they derived from. The big challenge for vaccinologists is how to select the right antigens and to combine them with proper immune stimulatory components (adjuvants) in order to induce protective immunity. This Commentary outlines the authors' view on the current and future strategies for the efficient and rapid identification of the most effective protective antigens and adjuvants. Since efficacious subunit-based vaccines against recalcitrant pathogens are likely to require more than one antigen and/or immune stimulator, this poses the problem of how to make such vaccines economically acceptable. In this regard, the authors also present their view of how bacterial Outer Membrane Vesicles (OMVs) could become a promising platform for the development of future vaccines. The unique properties of OMVs might be exploited in the field of infectious diseases and oncology.

Negatively charged AuNP modified with monoclonal antibody against novel tumor antigen FAT1 for tumor targeting

BACKGROUND

Herein, we demonstrated the use of a newly generated anti FAT1 antibody (clone mAB198.3) for intracellular delivery of anionic gold NPs, to form active targeting Au nanoparticles with high payload characteristics.

METHODS

In vitro characterizations were determined by DLS, confocal microscopy, TEM, western blot, MALDI-TOF MS/MS analysis, MTT, ICP-MS and flow cytometry analysis. In vivo targeting efficacy was investigated by in vivo bio-imaging study and ICP-MS.

RESULTS

The specificity of the FAT1 recognition in colon cancer was confirmed by pre-adsorbing mAb198.3, adsorption dramatically abolished the antibody reactivity on colon cancer, thus confirming the binding specificity. The DLS size distribution profile of the AuCOOH, AuCOOH(Cy5)_ mAb198.3, AuCOOH(Cy5)_isotype has showed that the modified gold nanoparticles are well dispersed in water, PBS buffer and cell culture medium with 10 % FBS. By TEM measurement, the size of Au nanoparticles with spherical morphology is about 10-20 nm. AuCOOH_198.3 NPs were stable in an acidic environment, as well as in PBS buffer, cell culture media and media with 10 % serum. MTT results revealed that Au nanoparticles have well biocompatibility. TEM results indicated that conjugation of mAb198.3 on Au nanoparticles can be an effective delivery vehicle for negatively charged gold nanoparticles and increased its intracellular transport. It was also demonstrated by confocal microscopy that AuCOOH(Cy5)_mAb198.3 could attach to the cell membrane in very short time, then gradually delivered into cells. After 4 h incubation, almost all AuCOOH(Cy5)_mAb198.3 have been uptaken into or surrounding the cytoplasm and nucleus. In vivo results showed that only about 20 % of AuCOOH accumulated in tumor site due to EPR effect, while nearly 90 % of AuCOOH_mAb198.3 was found in tumor, providing sufficient evidence for receptor-specific targeting by mAb198.3.

CONCLUSION

According to in vitro and in vivo research results, the intracellular uptake of negatively charged AuCOOH_mAB198.3 particles is enhanced to a greater extent. Thus, AuCOOH_mAb198.3 holds significant potential to improve the treatment of cancer.

Abstract 4384A: A novel potential therapeutic target for breast, lung, ovary and colon cancer

We identified 89 novel candidate markers for prevalent cancers by a systematic Tissue microarray analysis (TMA) of a large collection of polyclonal antibodies (approximately 1600) raised against membrane-associated and secreted human proteins currently marginally characterized. Among them, here we report a novel cancer-associated protein, referred as EXN32, so far only marginally characterized. EXN32 is a metallo-protease highly conserved across species, known to be involved in ovarian folliculogenesis. An anti-EXN32 monoclonal antibody (mAb) detects the protein in a high percentage of in breast, lung, ovary, and colo-rectal (CRC) cancers (high-to-medium intensity ranging from 30 to 70% in different cancer types. An analysis of high density tissue microarrays (300-700 highly characterized clinical specimens per each cancer) shows that EXN32 is over-expressed in all cancer stages and grades. In breast cancer, a EXN32 it is over-expressed in Her-2+, PR+ and ER+ patients and also in triple negative cases. In colon cancer, EXN32 is over-expressed both in B-RAF and K-RAS mutant and wild type cancers. We also found that EXN32 over-expression is statistically associated to a low activation of cadherin and beta-catenin pathways. Moreover, its expression is also associated with other prognostic and predictive markers. This evidence opens the way to further investigations on the EXN32 role in the marker-associated pathways. A characterization of the protein biological role showed that alteration of EXN32 expression strongly hampers cell proliferation, migration and invasiveness. The molecular pathways in which the protein is involved show that it plays a role in the Unfolded Protein Response and defence against oxidative stress. Our findings reveal that EXN32 is strongly affected by reticular stress induced by thapsigargin. In addition, EXN32 silencing during reticular stress protect cells from expressing the stress marker Bip/Grp78. In addition, EXN32 is involved also in handling of oxidative stress. Indeed, EXN32 silencing in cells exposed to 1% O2 hypoxia, causing a mitochondrial delivery of oxidants and hence sustaining oxidative stress, leads to inhibition of the Nrf2-mediated anti-oxidant response and to reduction of accumulation of HIF-1, the master transcription factor instructing cells to respond to hypoxic stress. We are investigating the possibility that EXN32 may participate as a molecular starter to the survival response induced by extracellular stresses.

Results indicate EXN32 as a potential target for the design of novel drugs, such as aptamers, small molecules and protease inhibitors. For instance, molecules such as 2-PMPA and analogues are expected to inhibit EXN32 activity. Moreover, EXN32 and its specific mAb represent interesting tools for the molecular characterization of specific cancer subtypes. Investigations are ongoing to understand the prognostic and predictive value of EXN32.

Citation Format: Matteo Parri, Alberto Grandi, Susanna Campagnoli, Elisa De Camilli, Alice Santi, Boquan Jin, Paolo Sarmientos, Guido Grandi, Giuseppe Viale, Paola Chiarugi, Luigi Terracciano, Piero Pileri, Renata Maria Grifantini. A novel potential therapeutic target for breast, lung, ovary and colon cancer. [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 4384A. doi:10.1158/1538-7445.AM2015-4384A

Abstract 3575: Novel targets and monoclonal antibodies for antibody-drug conjugate therapy

The study focuses on two novel potential therapeutic targets identified by an immune-histochemistry (IHC) screening with a large collection of polyclonal antibodies (approximately 1600) raised against marginally characterized human proteins. Here we describe the molecular characterization of two surface-exposed proteins (EXN91 and EXN36) associated to different cancer types. EXN91 is an adhesion molecule and it acts as a signaling receptor, cell communication and motility. Prevalence studies showed that the protein is mainly detected in colon cancer (CRC)with high frequency (approximately 90%), both in early and advanced colon cancer stages, with a statistical association for early cancer stages. Moreover, the protein is clearly surface exposed in liver metastasis from colon. Experiments are ongoing to assess whether EXN91 is also expressed in precancerous conditions of colon and rectum that have the potential to develop into cancer.

Interestingly, EXN91 is over-expressed in KRAS and BRAF mutant CRC with high frequency. Moreover, an expanded IHC analysis revealed that it is also over-expressed and surface exposed in a number of other cancers, including HCC, RCC, bladder and endometrium cancer. Preliminary data showed that EXN91 behaves as an auto-antigen being able to induce specific autoantibodies in CRC patients.

EXN36 is mainly over-expressed in ovary and breast cancers (frequency of approximately 30-40%), including triple negative breast cancer. EXN36 prevalence studies in different cancer entities are ongoing. Moreover, EXN36 is involved in cell proliferation, migration and invasiveness.

Murine monoclonal antibodies (mAb) able to recognize EXN91 and EXN36 on the surface of cancer cells show potential for specific therapeutic indications. In particular, a murine mAb recognizes EXN91 on the surface of colon cancer cells, including KRAS and BRAF mutant CRC. This antibody inhibits growth of colon cancer in xenograft mouse models. Concerning anti-EXN36 antibodies, they are able to bind the surface of different breast and ovary cancer cells.

EXN36 and EXN91 mAbs show a high number of binding sites on the cell surface. The mAb specificity has been confirmed in different immunoassays by gene silencing and peptide competition assays. Moreover, they show limited IHC reactivity in normal tissues.

The anti-EXN36 and antiEXN91 antibodies are efficiently internalized by cancer cells, suggesting that they can be exploited for the development of Antibody-Drug-Conjugate (ADC). Initial results from in vitro studies show that these antibodies, when tested in drug screening assays with Protein G conjugated to commercially available drugs show significant anti-tumor activity with a specific conjugation chemistry.

Overall, the results indicate that EXN36, EXN91 and their mAbs could be developed for the targeted therapy of different cancer indications at high medical need.

Citation Format: Matteo Parri, Susanna Campagnoli, Alberto Grandi, Elisa De Camilli, Paolo Sarmientos, Boquan Jin, Guido Grandi, Giuseppe Viale, Luigi Terracciano, Piero Pileri, Renata Maria Grifantini. Novel targets and monoclonal antibodies for antibody-drug conjugate therapy. [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 3575. doi:10.1158/1538-7445.AM2015-3575

Abstract 4622: Discovery of a novel target for monoclonal antibody therapy of breast and ovary cancers

In our recent research activities, we identified a panel of novel candidate markers for prevalent cancers by a systematic immune-histochemical screening with a large collection of polyclonal antibodies (approximately 1600) raised against membrane-associated and secreted human proteins currently marginally characterized. Of utmost interest were those proteins over-expressed detected in one or more tumors showing surface exposure on cancer cells. Among them, here we describe the molecular characterization of a novel surface-associated protein (EXN36) belonging to the lectin-binding protein family for which very little is presently known. We found that the protein is mainly over-expressed in breast and ovary cancers (frequency of approximately 30-40% of tested cases, based on analysis of 50 patients) and it is involved in cell proliferation, migration and invasiveness, as demonstrated by gene silencing. With the intent of exploiting EXN36 as therapeutic target for monoclonal antibody (mAb) therapy, highly specific murine mAbs were generated and proved to recognize the protein on the surface of selected breast and ovary cell lines. Of particular interest are two mAbs, which, upon binding, are efficiently internalized by breast and ovary cancer cells. These two mAbs influence the viability of breast and ovary cells in vitro. One of them shows antibody-dependent cell-mediated cytotoxicity in vitro in breast cancer cells. An analysis of their biodistribution in normal human tissues showed that these mAbs have limited cytoplasmic reactivity in some tissues. Overall, the functional properties of the anti-EXN36 mAbs make them amenable for the generation of antibody-drug conjugates (ADCs). Moreover, they could be exploited for immune-nanoparticles targeted delivery systems. In vivo efficacy in breast and ovary xenograft cancer models are ongoing to evaluate their therapeutic activity either as naked antibodies or ADCs. Overall, data indicate that EXN36 and the specific mAbs represent innovative and promising tools for a targeted mAb therapy of breast and colon cancer, either alone or in combinatorial therapeutic strategies.

Citation Format: Alberto Grandi, Susanna Campagnoli, Matteo Parri, Elisa De Camilli, Boquan Jin, Paolo Sarmientos, Guido Grandi, Luigi Terracciano, Giuseppe Viale, Piero Pileri, Renata Maria Grifantini. Discovery of a novel target for monoclonal antibody therapy of breast and ovary cancers. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4622. doi:10.1158/1538-7445.AM2014-4622

Abstract 1769: A novel potential cancer marker and therapeutic target

In our recent research activities, we identified 89 novel candidate markers for prevalent cancers by a systematic Tissue microarray analysis (TMA) of a large collection of polyclonal antibodies (pAbs, approximately 1600) raised against membrane-associated and secreted human proteins currently marginally characterized. Monoclonal antibodies were generated towards 20 distinct antigens that are being characterized and validated for diagnostic and therapeutic applications.

Among them, here we describe the molecular characterization of a novel cancer -associated protein (referred as EXN32) belonging to the metallo-protease family and so far only marginally characterized. Immuno-histochemical analysis of Tissue Microarrays carrying clinical specimens from prevalent cancers and matched normal samples with the anti-EXN32 pAb showed that the protein is over-expressed in breast, lung, ovary,and colon cancers, with frequencies ranging from 30 to 70%. A characterization of the protein biological role showed that alteration of EXN32 expression significantly hampers cell proliferation, migration and invasiveness. Initial studies aimed at identifying the molecular pathways in which the protein is involved show that it plays a role in the response to the reticular stress and hypoxia. A highly specific murine monoclonal antibody (mAb) specifically recognizes the protein in the four cancer types. This mAb is currently used to discover statistical associations between EXN32 with specific clinic-pathological parameters using high density tissue microarrays carrying highly characterized clinical specimens (300-700 per each cancer). Available data on breast and colon show that EXN32 is over-expressed in all cancer stages and grades. In breast cancer, a EXN32 bio-distribution analysis versus clinically relevant surface receptors shows that the protein is over-expressed in Her-2+, PR+ and ER+ patients and also in triple negative cases. In colon cancer, EXN32 over-expression shows statistical correlation with a panel of key molecular markers such as beta-catenin, e-cadherin, TGFbeta and others, and open the way to further investigations on the EXN32 role in their associated pathways. Overall, results indicate EXN32 as a potential target for the design of novel drugs, such as aptamers, si-RNA and small molecules. The EXN32 specific mAb represents an interesting tool for the molecular characterization of specific cancer subtypes. Investigations are ongoing to understand the predictive value of EXN32 for state-of art and innovative therapeutic strategies.

Citation Format: Matteo Parri, Susanna Campagnoli, Alberto Grandi, Elisa De Camilli, Valentina Farini, Serenella Eppenberger, Paola Chiarugi, Paolo Sarmientos, Boquan Jin, Guido Grandi, Giuseppe Viale, Luigi Terracciano, Piero Pileri, Renata Maria Grifantini. A novel potential cancer marker and therapeutic target. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1769. doi:10.1158/1538-7445.AM2014-1769

Angiopoietin-like 7, a novel pro-angiogenetic factor over-expressed in cancer

Angiopoietin-like (ANGPTL) proteins are secreted proteins showing structural similarity to members of the angiopoietin family. Some ANGPTL proteins possess pleiotropic activities, being involved in cancer lipid, glucose energy metabolisms, and angiogenesis. ANGPTL7 is the less characterized member of the family whose functional role is only marginally known. In this study, we provide experimental evidences that ANGPTL7 is over-expressed in different human cancers. To understand the role played by ANGPTL7 in tumor biology, we asked whether ANGPTL7 is endogenously expressed by malignant cells or in response to environmental stimuli. We found that ANGPTL7 is marginally expressed under standard growth condition while it is specifically up-regulated by hypoxia. Interestingly, the protein is secreted and partially associated with the exosomal fraction, suggesting that it could be found in the systemic circulation of oncologic patients and act in an endocrine way. Moreover, we found that ANGPTL7 exerts a pro-angiogenetic effect on human differentiated endothelial cells by stimulating their proliferation, motility, invasiveness, and capability to form capillary-like networks while it does not stimulate progenitor endothelial cells. Finally, we showed that ANGPTL7 promotes vascularization in vivo in the mouse Matrigel sponge assay, thereby accrediting this molecule as a pro-angiogenic factor.

Abstract C190: A novel monoclonal antibody for colon cancer therapy

In our recent research activities, we identified 89 novel candidate markers for prevalent cancers by a systematic Tissue microarray analysis (TMA) of a large collection of polyclonal antibodies (approximately 1600) raised against membrane-associated and secreted human proteins currently marginally characterized. Monoclonal antibodies were generated towards 20 distinct antigens that are being characterized and validated for diagnostic and therapeutic applications.

Here we describe a monoclonal antibody (mAb) targeting a protein of the protocadherin- family in colo-rectal cancer (CRC). The antibody specifically recognizes its target protein in cancer tissues, with concomitant negligible or marginal reactivity in normal colon. The protein was not previously described as CRC target. IHC data from CRC samples of approximately 200 patients, (collected at the bio-bank of the institute for Pathology of Basel, Switzerland and at the European Institute of Pathology of Milan, Italy) showed that the antibody binds up to 80% CRC cases (stages from 1 to 4) with high or moderate intensity. In most cases, the antibody gives plasma membrane by Immune Histochemistry (IHC). An expanded analysis on approximately 1000 CRC cases is ongoing to assess whether the membranous IHC staining associates with specific clinic-pathological parameters.

IHC analysis of 35 normal human tissues revealed that it gives intracellular staining in skeletal muscle, pituitary glands and prostate, whereas it gives background irrelevant staining in the other 32 tissues. The antibody is able to bind the surface of different colon cancer cells in vitro and in vivo. Upon binding it is efficiently internalized by colon cancer cells, suggesting that it can be exploited for the development of Antibody-Drug-Conjugate (ADC). Moreover, it inhibits tumor growth in athymic nude mice bearing HCT15 and HT29 colon cancer xenografts. Overall, data indicate that this monoclonal antibody could be developed for a targeted therapy of colo-rectal cancers, alone or in combinatorial strategies.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C190.

Citation Format: Alberto Grandi, Susanna Campagnoli, Matteo Parri, Elisa De Camilli, Ilaria Naldi, Lisa Gherardini, Caterina Cinti, Luigi Terracciano, Boquan Jin, Paolo Sarmientos, Giuseppe Viale, Guido Grandi, Piero Pileri, Renata Maria Grifantini. A novel monoclonal antibody for colon cancer therapy. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C190.

Abstract B7: Angiopoietin like 7, a novel pro-angiogenetic factor over-expressed in cancer

Angiopoietin like (ANGPTL) proteins are secreted proteins showing structural similarity to members of the angiopoietin family. Some ANGPTL proteins possess pleiotropic activities, being involved in cancer lipid, glucose energy metabolisms and angiogenesis. ANGPTL7 is the less characterized member of the family whose functional role is only marginally known. In this study we provide experimental evidences that ANGPTL7 is over-expressed in different human cancers. To understand the role played by ANGPTL7 in tumor biology, we asked whether ANGPTL7 is endogenously expressed by malignant cells or in response to environmental stimuli. We found that ANGPTL7 is marginally expressed under standard growth condition while it is specifically up-regulated by hypoxia. The regulatory mechanism underlining the ANGPTL7 response to hypoxia need to be elucidated. Interestingly, the protein is secreted and partially associated with the exosomial fraction, suggesting that it could be found in the systemic circulation of oncologic patients and act in an endocrine way. Moreover we found that ANGPTL7 exerts a pro-angiogenetic effect on human differentiated endothelial cells by stimulating their motility, invasiveness and capability to form capillary-like networks while it does not stimulate bone marrow derived progenitor endothelial cells. Finally, we showed that ANGPTL7 promotes vascularization in vivo in the mouse matrigel sponge assay, thereby accrediting this molecule as a pro-angiogenic factor. This suggests that ANGPTL7 could be an attractive therapeutic target for anti-angiogenic tumor therapy.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B7.

Citation Format: Matteo Parri, Laura Pietrovito, Alberto Grandi, susanna campagnoli, Piero Pileri, Elisa De Camilli, Laura Bianchini, Guido Grandi, Giuseppe Viale, Paola Chiarugi, Renata Maria Grifantini. Angiopoietin like 7, a novel pro-angiogenetic factor over-expressed in cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B7.

Abstract 2857: Monoclonal antibodies against novel tumor markers for cancer diagnosis and treatment

In our recent research activities, we identified a group of novel candidate tumor markers for prevalent cancers. Tissue microarray (TMA) representing breast, lung colon ovary and prostate cancers were analyzed by a high-throughput immunohistochemistry screening using of a library of 1600 mouse antibodies raised against membrane-associated and secreted human proteins for which little is known in the scientific literature. 89 proteins were found over-expressed in one or more of the five tumors under analysis. IHC analysis on TMA representing tissues from 50 patients per each of the five cancers allowed to select a group of 20 potential markers over-expressed in cancer with frequencies ranging from 20 to 96%, with concomitant marginal expression in normal tissues. With the aim at validating these proteins as novel markers for patient stratification, prognosis and response to therapy, highly specific monoclonal antibodies (mAbs) have been generated against them. Currently, mAbs against 4 markers able to selectively detect their target proteins in cancers by IHC have been already identified (positivity ranging from 15 up to 94%, and showing membranous or intracellular staining). The target proteins of these mAbs include:1) a scavenger receptor protein; 2) a putative metallo-protease, 3) a lectin-binding protein involved in the innate immune response, 4) a cadherin- homologous protein. The mAb clinical value is being examines using high-density TMA representing patients with known history and follow-up for breast (1553 patients), colon (1420 patients), lung (1527 patients), ovary (112 patients) and prostate (553 patients) cancers have been generated. The patient cohorts have been collected at the biobank of the institute for Pathology of Basel to select pools of prognostic/predictive monoclonal antibodies capable of discriminating i) patients with favorable or adverse prognosis, and ii) patients that respond/do not respond to specific therapeutic interventions. Available data indicated that these antibodies, alone and in combinations, show significant association with specific clinical features (formation of metastasis, progression-free survival, survival time). Interesting, some of available antibodies show therapeutic activity in preclinical cancer models. These antibodies are able to bind the surface of cancer cells in vitro and in vivo. Avalable data show that one mAb targeting the cadherin-like protein inhibits tumor growth in athymic nude mice bearing HCT15 and HT29 colon cancer xenograft models. Overall, these novel markers and their specific monoclonal antibodies could offer new opportunities for cancer diagnosis and treatment.

Citation Format: Renata Maria Grifantini, Piero Pileri, Matteo Parri, Alberto Grandi, Susanna Campagnoli, Renzo Nogarotto, Elena De Camilli, Serenella Eppenberger, Luigi Terracciano, Giuseppe Viale, Guido Grandi, Paolo Sarmientos. Monoclonal antibodies against novel tumor markers for cancer diagnosis and treatment . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2857. doi:10.1158/1538-7445.AM2013-2857

Abstract 5533: Novel targets and monoclonal antibodies for cancer therapy

Cancer therapeutic targets is an extremely active research field in both academia and pharmaceutical companies. In our recent research activities we identified by a high-throughput immunohistochemistry screening of Tissue microarray (TMA), a panel of 89 novel candidate tumor markers for prevalent cancers representing breast, lung colon ovary and prostate carcinomas. The novel marker candidates were found over-expressed in one or more of the five tumors under analysis, with significant frequency. Three of them seems to be promising therapeutic targets for monoclonal antibody therapy, being exposed on the surface of cancer cells. They include: 1) a lectin binding protein, over-expressed in breast, lung and ovary cancer; 2) a protein involved in iron homoeostasis and over-expressed in breast, colon, lung and ovary cancers, 3) a cadherin homologous protein detected in colon, lung and ovary cancers. Gene silencing using siRNA technology and/or over-expression experiments using marker-encoding plasmids significantly alter cell proliferation, migration, invasiveness and clonal growth in vitro, indicating that expression of the three proteins confers cell phenotypes relevant for tumor progression. Highly specific murine monoclonal antibodies (mAbs) were generated against the three proteins and proved to bind the surface of cancer cells lines. Of particular interest is a murine mAb targeting the cadherin-like protein that, upon binding to the cell surface, is efficiently internalized by cancer cells, suggesting that it is amenable to the development of antibody-drug conjugates. This mAb did not show any relevant IHC cross-reactivity in the 35 human tissues requested by FDA to demonstrate antibody specificity. Furthermore this mAb significantly inhibited tumor growth in athymic nude mice bearing HCT15 and HT29 colon cancer xenograft models. Finally, IHC analysis of approximately 300 colon cancer clinical samples indicates that the antibody stains a large fraction of colon cancer samples, and gives intense membranous staining in specific patients’ group. Overall, data indicate that this antibody could be developed as a novel tool for a targeted therapy of colo-rectal cancer, alone or in combination with other treatments

Citation Format: Alberto Grandi, Matteo Parri, Susanna Campagnoli, Renzo Nogarotto, Elisa De Camilli, Ilaria Naldi, Caterina Cinti, Paolo Sarmientos, Guido Grandi, Luigi Terracciano, Giuseppe Viale, Piero Pileri, Renata Maria Grifantini. Novel targets and monoclonal antibodies for cancer therapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5533. doi:10.1158/1538-7445.AM2013-5533

Abstract B180: Novel candidate tumor markers identified by a high-throughput “immuno-reverse-proteomics” approach

Cancer biomarker discovery is an extremely active research field in both academia and pharmaceutical companies. Here we present a group of candidate tumor markers identified by a high-throughput immunohistochemistry approach based on the use of a library of 1600 mouse antibodies raised against marginally-characterized human proteins. Tissue microarray (TMA) representing breast, lung colon ovary and prostate cancers were used to identify novel tumor markers. Eighty-nine proteins were found over-expressed in one or more of the five tumors under analysis. The validation process is still in progress and so far has been undertaken on twenty-six of the eighty-nine hits. They are confirmed over-expressed in TMAs carrying 50 tumor samples for each tumor type and, in particular, nineteen proteins were found expressed in one or more tumors with frequencies ranging from 20% to 96%. Interestingly, some of the proteins are simultaneously over-expressed in specific patients' groups, thus opening the possibility of tissue diagnostic/prognostic/predictive applications based on combinatorial markers. Moreover, in vitro characterization studies indicated that some markers play a pivotal role in tumor-related cell processes like cell proliferation (EXN32; EXN36; EXN7), invasiveness (EXN32; EXN36; EXN7; EXN4), clonal growth (EXN1) and pro-angiogenesis (EXN11). A panel of monoclonal antibodies highly specific the biomarkers is already available and proved to specifically detect the markers in tumor cells derived from surgical resections. The newly identified candidate markers are new tools for the development of specific drug therapies and diagnostic products.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B180.

A novel polyclonal antibody library for expression profiling of poorly characterized, membrane and secreted human proteins

The YOMICS™ antibody library (http://www.yomics.com/) presented in this article is a new collection of 1559 murine polyclonal antibodies specific for 1287 distinct human proteins. This antibody library is designed to target marginally characterized membrane-associated and secreted proteins. It was generated against human proteins annotated as transmembrane or secreted in GenBank, EnsEMBL, Vega and Uniprot databases, described in no or very few dedicated PubMed-linked publications. The selected proteins/protein regions were expressed in E. coli, purified and used to raise antibodies in the mouse. The capability of YOMICS™ antibodies to specifically recognize their target proteins either as recombinant form or as expressed in cells and tissues was confirmed through several experimental approaches, including Western blot, confocal microscopy and immunohistochemistry (IHC). Moreover, to show the applicability of the library for biomarker investigation by IHC, five antibodies against proteins either known to be expressed in some cancers or homologous to tumor-associated proteins were tested on tissue microarrays carrying tumor and normal tissues from breast, colon, lung, ovary and prostate. A consistent differential expression in cancer was observed. Our results indicate that the YOMICS™ antibody library is a tool for systematic protein expression profile analysis that nicely complements the already available commercial antibody collections.

Abstract 5579: Novel proteins highly expressed in tumor identified by a high throughput immunoproteomic approach

Cancer biomarker discovery is an extremely active research track in both academia and pharma industries. Several high throughput technologies were applied through the years to identify proteins specifically related to cancerous phenotype. However, most putative biomarkers identified from conventional proteomic/transcriptomic strategies still need to be clinically validated. Here we present a cancer biomarker discovery approach based on the use of a large library of antibodies raised against recombinant human proteins to detect tumor-associated proteins by immune-histochemistry analysis of clinical tumor tissues. Starting from the whole human genome, genes encoding proteins predicted as membrane- or secreted were selected and high through-put cloned and expressed. Recombinant proteins were used to build a polyclonal antibody library (YOMICS®) currently comprising more than 1700 murine immune sera. The ability of sera to recognize specific targets predominantly present in tumors was assessed by Tissue MicroArray (TMA, a miniaturized immunohistochemistry analysis) of tumor tissue samples and healthy controls from pedigreed patients affected by the most common human tumor types, including colon, ovary, breast, lung, ovary and prostate cancers.

While the screening is still in progress, six antibodies were identified showing high reactivity on a high percentage (ranging from 40 to 95%) of tumor tissues on one or more cancer type, with negative staining on normal tissues. The corresponding protein targets, being novel tumor-associated proteins, were validated and characterized at cellular and molecular level by analyzing their expression, cellular localization and biological role in a panel of tumor cell lines. Interestingly, two of the six proteins are localized at the plasma membrane, while the other proteins are intracellular. Data so far available indicate that one of the six proteins confers an invasive phenotype to tumor cell lines. The newly identified proteins are promising candidates as new biomarkers and could be exploited to develop target-specific drug therapies.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5579.

Electron-Attachment Resonances of Glycine Zwitterions from Quantum Scattering Calculations: Modeling Macrosolvation Effects

A computational study of the quantum dynamics for low-energy electrons scattered by the isolated zwitterionic species of the glycine molecule is carried out using a model interaction potential described in the main text. The macroscopic effects of water solvation on the target molecule in the electron scattering problem are described through a continuum polarizable model (CPCM) which modifies the target molecular structure. In such a way, realistic molecular orbitals depicting the glycine zwitterion in solution are used to model the electron-molecule interaction. The results of the calculations indicate the presence of five different transient negative ions (TNIs) formed at energies from the threshold and up to about 6 eV. Although no nuclear motion was explicitly considered in the ensuing decay processes, the analysis of the nodal structures and density distributions for the resonant excess electron wavefunctions over the molecular space suggests possible anionic fragmentations that produce (Gly-H)-, H-, -CO2-, and -NH3. The likely consequences of such releases into the medium are briefly discussed.

H- desorption from uracil via metastable electron capture

In this Letter we report an analysis of the quantum dynamics for the scattering of slow electrons off uracil molecules, leading to the formation of a trapped, metastable anionic state at around 9 eV of energy. This resonant state is seen to be capable of describing an anionic molecular precursor which can explain the desorption of the H- species observed in experiments on film deposited uracil samples.

Low-energy electron scattering by cubane: resonant states and Ramsauer-Townsend features from quantum calculations in the gas phase

Calculations are carried out, using a nonempirical modeling of the interaction potential and solving the quantum scattering coupled channel equations, for low energy electron scattering from cubane (C8H8) molecules in the gas phase. Total integral cross sections are obtained and partial contributions are analyzed for the most important irreducible representations that describe the continuum electron in the Oh molecular symmetry. Several trapping resonances are found and analyzed in terms of the molecular-type features of the resonant electron states associated with them. A Ramsauer-Townsend minimum is also found and its possible behavior related to features of the scattering length as k --> 0.

Master Amino acid Pattern as sole and total substitute for dietary proteins during a weight-loss diet to achieve the body's nitrogen balance equilibrium

Results of this multicentric study have shown that by giving Master Amino acid Pattern (MAP) as a sole and total substitute of dietary proteins to 500 overweight participants undergoing the American Nutrition Clinics/Overweight Management Program (ANC/OMP), the participants' body nitrogen balance could be maintained in equilibrium with essentially no calories (MAP 1 g=0.04 kcal), thereby preserving the body's structural and functional proteins, eliminating excessive water retention from the interstitial compartment, and preventing the sudden weight increase after study conclusion commonly known as the yo-yo effect. Study results have shown that the use of MAP, in conjunction with the ANC/OMP regimen, has proven to be safe and effective by preventing those adverse effects associated with a negative nitrogen balance, such as oversized or flabby tissue, stretch marks, the sagging of breast tissue, increased hair loss, faded hair color, and fragile or brittle nails. Also prevented were those anomalies commonly associated with weight-loss diets, such as hunger, weakness, headache caused by ketosis, constipation, and decreased libido. The use of MAP in conjunction with the ANC/OMP also allowed for mean weight loss of 2.5 kg (5.5 lb) per week, achieved through reduction of excessive fat tissue and elimination of excessive water retention from the interstitial compartment.

Master Amino acid Pattern as substitute for dietary proteins during a weight-loss diet to achieve the body's nitrogen balance equilibrium with essentially no calories

Results of this multicentric study have shown that by giving 10 g (10 tablets) of Master Amino acid Pattern (MAP) as a substitute for dietary proteins, once a day, to 114 overweight participants undergoing the American Nutrition Clinics/Overweight Management Program (ANC/OMP), the participants' nitrogen balance could be maintained in equilibrium with essentially no calories (MAP 1 g=0.04 kcal), thereby preserving the body's structural and functional proteins, eliminating excessive water retention from the interstitial compartment, and preventing the sudden weight increase after study conclusion commonly known as the yo-yo effect. Study results have shown that the use of MAP, in conjunction with the ANC/OMP, has proven to be safe and effective by preventing those adverse effects associated with a negative nitrogen balance, such as oversized or flabby tissue, stretch marks, sagging of breast tissue, increased hair loss, faded hair color, and fragile or brittle nails. Also preventing those anomalies commonly associated with weight-loss diets, such as hunger, weakness, headache caused by ketosis, constipation, or decreased libido, the use of MAP, in conjunction with the ANC/OMP, allowed for mean weight loss of 1.4 kg (3 lb) per week.

Comparative results between two groups of track-and-field athletes with or without the use of Master Amino acid Pattern as protein substitute

Comparative results of this study have shown that athletes, by taking the Master Amino acid Pattern (MAP) as a dietary protein substitute and performing physical activity, have had (1) increased body muscle mass, strength, and endurance; (2) decreased fat mass; (3) increased basal metabolism rate; (4) greater improvement in performance of the nonprevailing muscles compared to the prevailing ones; and (5) improved muscular and hematologic lactate clearance, which allows for better muscle performance and faster muscle recovery after physical activity. It was concluded that the use of MAP as a dietary protein substitute in conjunction with physical activity can provide a safe and unprecedented way to optimize the body's protein synthesis, thereby improving anthropometric characteristics and physical and physiologic performance.

Results of taking Master Amino acid Pattern as a sole and total substitute of dietary proteins in an athlete during a desert crossing

Study results show that a 51-year-old female athlete, while taking the Master Amino acid Pattern (MAP) as a sole and total substitute for dietary protein, and performing physical activity, experienced (1) increased body muscle mass, strength, and endurance; (2) decreased body fat mass; (3) greater increase in performance of the nonprevailing muscles compared to the prevailing muscles; (4) improved cardiorespiratory performance; and (5) increased red blood cells, hemoglobin, and hematocrit parameters. It was concluded, confirming previous findings, that use of MAP as a sole and total substitute for dietary protein, in conjunction with physical activity, provides safer, unprecedented optimization of the body's protein synthesis, thereby improving anthropometric characteristics and physical and physiologic performance.

Measuring left ventricular dimensions by conductance catheter in the rabbit

A miniaturized (3.5 F), six-electrode conductance catheter was tested in 18 anaesthetized adult rabbits (weight 3.8-4.6 kg, ethylurethane 2.5 g kg-1). In eight animals, the reference stroke volume (ref-SV) was obtained by an electromagnetic flow probe, while reference end-diastolic volume (ref-LVEDV) was computed by dividing ref-SV by undamped thermal dilution ejection fraction (ref-EF) estimates. Comparisons with conductance indexes (z-SV, z-LVEDV and z-EF) were made at baseline, subsequent levels of graded haemorrhage and reinfusion state. In 10 animals intraventricular segmental conductance was compared with echocardiographic left ventricular cross-section (5 MHz short-focus probe), in the basal state and during acute left ventricular volume changes generated by inferior vena cava balloon occlusion. In each experiment, parallel conductance due to the tissues surrounding the left ventricle (Gp) was determined by infusing a 5M NaCl solution bolus into the right ventricle. Linear regression analysis showed fairly good correlations between z-SV, z-LVEDV and z-EF and reference indexes (r = 0.84, r = 0.83, and r = 0.72, respectively; P less than 0.001 in all cases). A linear regression analysis from 17 interventions (inferior vena cava balloon occlusion) showed a good correlation between left ventricular echocardiographic cross-sectional area and conductance, and higher correlation coefficients, r ranging from 0.870 to 0.986 were obtained from continuously sampled conductance and echographic measurements. Parallel conductance Gp was correlated (r = 0.807, P less than 0.01) with the intercept of the regression line of echographic vs conductance data. The determination of Gp thus improved the accuracy of the left ventricular dimension estimate. These results add further evidence for the possibility of continuous monitoring of left ventricular dimension by means of a conductance catheter, and demonstrate the feasibility of such studies on small experimental animals.