Universal expression of cell adhesion molecule NCAM in neuroblastoma in contrast to L1: implications for different roles in tumor biology of neuroblastoma?

Plasma-Derived Exosome Proteins as Novel Diagnostic and Prognostic Biomarkers in Neuroblastoma Patients

Neuroblastoma (NB) is the most common extracranial solid tumor during infancy, causing up to 10% of mortality in children; thus, identifying novel early and accurate diagnostic and prognostic biomarkers is mandatory. NB-derived exosomes carry proteins (Exo-prots) reflecting the status of the tumor cell of origin. The purpose of this study was to characterize, for the first time, the Exo-prots specifically expressed in NB patients associated with tumor phenotype and disease stage. We isolated exosomes from plasma specimens of 24 HR-NB patients and 24 low-risk (LR-NB) patients at diagnosis and of 24 age-matched healthy controls (CTRL). Exo-prot expression was measured by liquid chromatography-mass spectrometry. The data are available via ProteomeXchange (PXD042422). The NB patients had a different Exo-prot expression profile compared to the CTRL. The deregulated Exo-prots in the NB specimens acted mainly in the tumor-associated pathways. The HR-NB patients showed a different Exo-prot expression profile compared to the LR-NB patients, with the modulation of proteins involved in cell migration, proliferation and metastasis. NCAM, NCL, LUM and VASP demonstrated a diagnostic value in discriminating the NB patients from the CTRL; meanwhile, MYH9, FN1, CALR, AKAP12 and LTBP1 were able to differentiate between the HR-NB and LR-NB patients with high accuracy. Therefore, Exo-prots contribute to NB tumor development and to the aggressive metastatic NB phenotype.

Ubiquitous Neural Cell Adhesion Molecule (NCAM): Potential Mechanism and Valorisation in Cancer Pathophysiology, Drug Targeting and Molecular Transductions

Neural cell adhesion molecule, an integrated molecule of immunoglobulin protein superfamily involved in cell-cell adhesion, undergoes various structural modifications through numerous temporal-spatial regulations that generously alter their expressions on cell surfaces. These varied expression patterns are mostly envisioned in the morphogenesis and innervations of different human organs and systems. The considerable role of NCAM in neurite growth, brain development and etc. and its altered expression of NCAM in proliferating tumour cells and metastasis of various human melanomas clearly substantiate its appropriateness as a cell surface marker for diagnosis and potential target for several therapeutic moieties. This characteristic behaviour of NCAM is confined to its novel biochemistry, structural properties, signalling interactions and polysialylation. In particular, the characteristic expressions of NCAM are mainly attributed by its polysialylation, a post-translational modification that attaches polysialyl groups to the NCAM. The altered expression of NCAM on cell surface develops curiosity amidst pharmaceutical scientists, which drives them to understand its role of such expressions in various human melanomas and to elucidate the promising therapeutic strategies that are currently available to target NCAM appositely. Therefore, this review article is articulated with an insight on the altered expressions of NCAM, the clinical significances and the consequences of such atypical expression patterns in various human organs and systems.

Nanotechnology-Based Diagnostic and Therapeutic Strategies for Neuroblastoma

Neuroblastoma (NB), as the most common extracranial solid tumor in childhood, is one of the critical culprits affecting children's health. Given the heterogeneity and invisibility of NB tumors, the existing diagnostic and therapeutic approaches are inadequate and ineffective in early screening and prognostic improvement. With the rapid innovation and development of nanotechnology, nanomedicines have attracted widespread attention in the field of oncology research for their excellent physiological and chemical properties. In this review, we first explored the current common obstacles in the diagnosis and treatment of NB. Then we comprehensively summarized the advancements in nanotechnology-based multimodal synergistic diagnosis and treatment of NB and elucidate the underlying mechanisms. In addition, a discussion of the pending challenges in biocompatibility and toxicity of nanomedicine was conducted. Finally, we described the development and application status of nanomaterials against some of the recognized targets in the field of NB research, and pointed out prospects for nanomedicine-based precision diagnosis and therapy of NB.

Cell Adhesion Molecules in Neuroblastoma: Complex Roles, Therapeutic Potential

Neuroblastoma, a biologically heterogeneous tumor derived from neural crest cells, accounts for approximately 15% of childhood deaths from cancer. Recently, scientific literature has explored the role of cell adhesion molecules (CAMs) in cancer metastasis through cell detachment, migration, and invasion. Through a review of the current literature, it is evident that expression of different CAMs on neuroblastoma tumors is associated with favorable or unfavorable clinical prognosis. In patients diagnosed with neuroblastoma, treatment strategies include chemotherapy, surgery, radiotherapy, stem cell transplant, and more recently, immunotherapy and other targeted therapies. Long term survival remains poor despite multimodality treatment, especially for children with high-risk neuroblastoma, making it more necessary to explore innovative targeted therapies. CAMs have immense potential as therapeutic targets, but there is a need for growth and scientific exploration before CAM therapies become clinically useful.

Chimeric Antigen Receptor (CAR) T Cell Therapy for Metastatic Melanoma: Challenges and Road Ahead

Metastatic melanoma is the most aggressive and difficult to treat type of skin cancer, with a survival rate of less than 10%. Metastatic melanoma has conventionally been considered very difficult to treat; however, recent progress in understanding the cellular and molecular mechanisms involved in the tumorigenesis, metastasis and immune escape have led to the introduction of new therapies. These include targeted molecular therapy and novel immune-based approaches such as immune checkpoint blockade (ICB), tumor-infiltrating lymphocytes (TILs), and genetically engineered T-lymphocytes such as chimeric antigen receptor (CAR) T cells. Among these, CAR T cell therapy has recently made promising strides towards the treatment of advanced hematological and solid cancers. Although CAR T cell therapy might offer new hope for melanoma patients, it is not without its shortcomings, which include off-target toxicity, and the emergence of resistance to therapy (e.g., due to antigen loss), leading to eventual relapse. The present review will not only describe the basic steps of melanoma metastasis, but also discuss how CAR T cells could treat metastatic melanoma. We will outline specific strategies including combination approaches that could be used to overcome some limitations of CAR T cell therapy for metastatic melanoma.

The panel of syntaxin 1 and insulinoma-associated protein 1 outperforms classic neuroendocrine markers in pulmonary neuroendocrine neoplasms

Syntaxin-1 (STX1) is a recently described highly sensitive and specific neuroendocrine marker. We evaluated the applicability of STX1 as an immunohistochemical marker in pulmonary neuroendocrine neoplasms (NENs). We compared STX1 with established neuroendocrine markers, including insulinoma-associated protein 1 (INSM1). Typical carcinoids (n = 33), atypical carcinoids (n = 7), small cell lung carcinomas ([SCLCs] n = 30), and large cell neuroendocrine lung carcinomas (n = 17) were immunostained using tissue microarray for STX1, chromogranin A, synaptophysin, CD56, and INSM1. Eighty-four of eighty-seven (96.5%) NENs showed STX1 positivity. Carcinoids and LCNECs typically presented a combined strong membranous and weak cytoplasmic staining pattern; cytoplasmic expression was predominately observed in SCLCs. The sensitivity of STX1 was 90% in SCLCs and 100% in typical carcinoids, atypical carcinoids, and large cell neuroendocrine lung carcinomas. The overall sensitivity of STX1 in pulmonary NENs was 96.6%, and the sensitivity of the other markers was as follows: chromogranin A (85.2%), synaptophysin (85.2%), CD56 (92.9%), and INSM1 (97.7%). STX1 was found to be an excellent neuroendocrine marker of pulmonary NENs, with sensitivity and specificity surpassing that of classic markers. We propose a panel of STX1 and INSM1 for the routine immunohistochemical workup of pulmonary NENs.

AQP1-Driven Migration Is Independent of Other Known Adverse Factors but Requires a Hypoxic Undifferentiated Cell Profile in Neuroblastoma

Neuroblastoma is a biologically very heterogeneous tumor with its clinical manifestation ranging from spontaneous regression to highly aggressive metastatic disease. Several adverse factors have been linked to oncogenesis, tumor progression and metastases of neuroblastoma including NMYC amplification, the neural adhesion molecule NCAM, as well as CXCR4 as a promoter of metastases. In this study, we investigate to what extent the expression of AQP1 in neuroblastoma correlates with changing cellular factors such as the hypoxic status, differentiation, expression of known adverse factors such as NMYC and NCAM, and CXCR4-related metastatic spread. Our results show that while AQP1 expression leads to an increased migratory behavior of neuroblastoma cells under hypoxic conditions, we find that hypoxia is associated with a reduction of NMYC in the same cells. A similar effect can be observed when using the tetracycline driven mechanism of SH-EP/Tet cells. When NMYC is not expressed, the expression of AQP1 is increased together with an increased expression of HIF-1α and HIF-2α. We furthermore show that when growing cells in different cell densities, they express AQP1, HIF-1α, HIF-2α, NMYC and NCAM to different degrees. AQP1 expression correlates with a hypoxic profile of these cells with increased HIF-1α and HIF-2α expression, as well as with NMYC and NCAM expression in two out of three neuroblastoma cell lines. When investigating cell properties of the cells that actually migrate, we find that the increased APQ1 expression in the migrated cells correlates with an increased NMYC and NCAM expression again in two out of three cell lines. Expression of the tumor cell homing marker CXCR4 varies between different tumor areas and between cell lines. While some migrated tumor cells highly express CXCR4, cells of other origin do not. In the initial phase of migration, we determined a dominant role of AQP1 expression of migrating cells in the scratch assay.

Isolation and preliminary characterization of a human 'phage display'-derived antibody against neural adhesion molecule-1 antigen interfering with fibroblast growth factor receptor-1 binding

BACKGROUND

The NCAM or CD56 antigen is a cell surface glycoprotein belonging to the immunoglobulin super-family involved in cell-cell and cell-matrix adhesion. NCAM is also over-expressed in many tumour types and is considered a tumour associated antigen, even if its role and biological mechanisms implicated in tumour progression and metastasis have not yet to be elucidated. In particular, it is quite well documented the role of the interaction between the NCAM protein and the fibroblast growth factor receptor-1 in metastasis and invasion, especially in the ovarian cancer progression.

OBJECTIVE

Here we describe the isolation and preliminary characterization of a novel human anti-NCAM single chain Fragment variable antibody able to specifically bind NCAM-expressing cells, including epithelial ovarian cancer cells.

METHODS

The antibody was isolate by phage display selection and was characterized by ELISA, FACS analysis and SPR experiments. Interference in EOC migration was analyzed by scratch test.

RESULTS

It binds a partially linear epitope lying in the membrane proximal region of two fibronectin-like domains with a dissociation constant of 3.43 × 10-8 M. Interestingly, it was shown to interfere with the NCAM-FGFR1 binding and to partially decrease migration of EOC cells.

CONCLUSIONS

According to our knowledge, this is the first completely human antibody able to interfere with this newly individuated cancer mechanism.

Verteporfin induces apoptosis and reduces the stem cell-like properties in Neuroblastoma tumour-initiating cells through inhibition of the YAP/TAZ pathway

Neuroblastoma is an embryonal malignancy of early childhood arising from the embryonic sympatho-adrenal lineage of the neural crest. About half of all cases are currently classified as high-risk of disease recurrence, with an overall survival rate of less than 40% at 5 years despite intensive therapy. Recent studies on matched primary tumours and at the relapse revealed downregulation of genes transcriptionally silenced by YAP as significant association with neuroblastoma relapse. Here, we evaluated the pharmacological targeting of YAP/TAZ with the YAP/TAZ-TEAD inhibitor Verteporfin (VP) in Tumour Initiating Cells (TICs) derived from High-Risk Neuroblastoma patients. VP treatment suppresses YAP/TAZ expression, induces apoptosis and causes the re-organization of the cytoskeleton reducing cells migration and clonogenic ability. Moreover, VP reduces the percentage of side population cells and ABC transporters involved in drug resistance, and the percentage of stem cell subpopulations CD133+ and CD44⁺ of TICs. Finally, we demonstrated that VP sensitizes TICs to the standard drugs used for neuroblastoma therapy etoposide and cis-platin opening the way to use VP as drug repositioning candidate for recurrent neuroblastoma.

Metastases to the Breast from Extramammary Nonhematological Malignancies: Case Series

Objective

This article aims to provide a better understanding of ultrasonography and immunohistochemistry of secondary nonhematological tumors of breast.

Methods

The study reviewed the ultrasound findings and immunohistochemical features of nonhematological metastatic breast tumor cases found in patients of West China Hospital, Sichuan University from 2007 to 2019. Each case was categorized as secondary breast malignancy using histopathological results.

Results

Fourteen cases were identified from West China Hospital database. Ten cases originated in the lung, 2 cases in the stomach, 1 case in the ovary and 1 case of neuroendocrine carcinomas. Fourteen masses were evaluated. Ultrasound findings showed that tumors were hypoechoic (14/14), irregular (13/14), indistinct margin (13/14), along a long axis parallel to the skin (11/14), lacked vascularity via color doppler flow imaging (9/14). Eight cases showed no posterior features. Calcification was found in 1 case of lung adenocarcinoma that had metastasized to the breast. Abnormal axillary lymph nodes were detected in 5 cases. Immunohistochemical analysis showed that estrogen receptor (ER) and progesterone receptor (PR) were both negative in 11 cases, including gastric and lung cancer metastasis. One case of ovarian metastasis was positive for ER and negative for PR. Six patients were positive for cytokeratin 7 (CK7) and negative for cytokeratin 20 (CK20), including lung and ovarian carcinoma metastasis. Thyroid transcription factor-1 (TTF-1) was positive in 9 of 10 pulmonary carcinoma metastases. The patient of ovarian metastasis was positive for Wilms' tumour 1 (WT-1) and carbohydrate antigen 125 (CA125). Two cases from gastric metastasis were positive for caudal-type homeobox 2 (CDX2).

Conclusion

Although breast ultrasound is not useful in distinguishing metastases from primary breast cancer, it is helpful in diagnosing breast lesions as oncological diseases and provide evidence for further examination of patients. Immunohistochemistry plays an important role in distinguishing secondary breast cancer from primary, especially in patients without tumor history.

ADVL1522: A phase 2 study of lorvotuzumab mertansine (IMGN901) in children with relapsed or refractory wilms tumor, rhabdomyosarcoma, neuroblastoma, pleuropulmonary blastoma, malignant peripheral nerve sheath tumor, or synovial sarcoma-A Children's Oncology Group study

BACKGROUND

Lorvotuzumab mertansine (IMGN901) is an antibody-drug conjugate linking an antimitotic agent (DM1) to an anti-CD56 antibody (lorvotuzumab). Preclinical efficacy has been noted in Wilms tumor, rhabdomyosarcoma, and neuroblastoma. Synovial sarcoma, malignant peripheral nerve sheath tumor (MPNST), and pleuropulmonary blastoma also express CD56. A phase 2 trial of lorvotuzumab mertansine was conducted to assess its efficacy, recommended phase 2 dose, and toxicities.

METHODS

Eligible patients had relapsed after or progressed on standard therapy for their tumor type. Lorvotuzumab mertansine (110 mg/m² per dose) was administered at the adult recommended phase 2 dose intravenously on days 1 and 8 of 21-day cycles. Dexamethasone premedication was used. Pharmacokinetic samples, peripheral blood CD56-positive cell counts, and tumor CD56 expression were assessed.

RESULTS

Sixty-two patients enrolled. The median age was 14.3 years (range, 2.8-29.9 years); 35 were male. Diagnoses included Wilms tumor (n = 17), rhabdomyosarcoma (n = 17), neuroblastoma (n = 12), synovial sarcoma (n = 10), MPNST (n = 5), and pleuropulmonary blastoma (n = 1). Five patients experienced 9 dose-limiting toxicities: hyperglycemia (n = 1), colonic fistula (n = 1) with perforation (n = 1), nausea (n = 1) with vomiting (n = 1), increased alanine aminotransferase in cycle 1 (n = 2), and increased alanine aminotransferase in cycle 2 (n = 1) with increased aspartate aminotransferase (n = 1). Non-dose-limiting toxicities (grade 3 or higher) attributed to lorvotuzumab mertansine were rare. The median values of the maximum concentration, half-life, and area under the curve from zero to infinity for DM1 were 0.87 µg/mL, 35 hours, and 27.9 µg/mL h, respectively. Peripheral blood CD56+ leukocytes decreased by 71.9% on day 8. One patient with rhabdomyosarcoma had a partial response, and 1 patient with synovial sarcoma achieved a delayed complete response.

CONCLUSIONS

Lorvotuzumab mertansine (110 mg/m² ) is tolerated in children at the adult recommended phase 2 dose; clinical activity is limited.

CHL1 and NrCAM are Primarily Expressed in Low Grade Pediatric Neuroblastoma

Background

Neural cell adhesion molecules like close homolog of L1 protein (CHL1) and neuronal glia related cell adhesion molecule (NrCAM) play an important role in development and regeneration of the central nervous system. However, they are also associated with cancerogenesis and progression in adult malignancies, thus gain increasing importance in cancer research. We therefore studied the expression of CHL1 and NrCAM according to the course of disease in children with neuroblastoma.

Methods

CHL1 and NrCAM expression levels were histologically assessed by tissue microarrays from surgically resected neuroblastoma specimens of 56 children. Expression of both markers was correlated to demographics as well as clinical data including metastatic dissemination and survival.

Results

CHL1 was expressed in 9% and NrCAM in 51% of neuroblastoma tissue samples. Expression of CHL1 was higher in patients with low Hughes grade 1a/b (p=0.01). NrCAM was more often detected in patients with a low International Staging System (INSS) score 1/2 (p=0.04).

Conclusion

CHL1 and NrCAM expression was associated with low-grade pediatric neuroblastoma. These adhesion molecules may play a role in early tumor development of neuroblastoma.

Dual and multi-targeted nanoparticles for site-specific brain drug delivery

In recent years, nanomedicines have emerged as a promising method for central nervous system drug delivery, enabling the drugs to overcome the blood-brain barrier and accumulate preferentially in the brain. Despite the current success of brain-targeted nanomedicines, limitations still exist in terms of the targeting specificity. Based on the molecular mechanism, the exact cell populations and subcellular organelles where the injury occurs and the drugs take effect have been increasingly accepted as a more specific target for the next generation of nanomedicines. Dual and multi-targeted nanoparticles integrate different targeting functionalities and have provided a paradigm for precisely delivering the drug to the pathological site inside the brain. The targeting process often involves the sequential or synchronized navigation of the targeting moieties, which allows highly controlled drug delivery compared to conventional targeting strategies. Herein, we focus on the up-to-date design of pathological site-specific nanoparticles for brain drug delivery, highlighting the dual and multi-targeting strategies that were employed and their impact on improving targeting specificity and therapeutic effects. Furthermore, the background discussion of the basic properties of a brain-targeted nanoparticle and the common lesion features classified by neurological pathology are systematically summarized.

CD56 expression in breast cancer induces sensitivity to natural killer-mediated cytotoxicity by enhancing the formation of cytotoxic immunological synapse

We examined the potential value of the natural killer (NK) cell line; NK-92, as immunotherapy tool for breast cancer (BC) treatment and searched for biomarker(s) of sensitivity to NK-92-mediated cytotoxicity. The cytotoxic activity of NK-92 cells towards one breast precancerous and nine BC cell lines was analyzed using calcein-AM and degranulation assays. The molecules associated with NK-92-responsiveness were determined by differential gene expression analysis using RNA-sequencing and validated by RT-PCR, immunostaining and flow cytometry. NK-target interactions and immunological synapse formation were assessed by fluorescence microscopy. Potential biomarker expression was determined by IHC in 99 patient-derived BC tissues and 10 normal mammary epithelial tissues. Most (8/9) BC cell lines were resistant while only one BC and the precancerous cell lines were effectively killed by NK-92 lymphocytes. NK-92-sensitive target cells specifically expressed CD56, which ectopic expression in CD56-negative BC cells induced their sensitivity to NK-92-mediated killing, suggesting that CD56 is not only a biomarker of responsiveness but actively regulates NK function. CD56 adhesion molecules which are also expressed on NK cells accumulate at the immunological synapse enhancing NK-target interactions, cytotoxic granzyme B transfer from NK-92 to CD56-expressing target cells and induction of caspase 3 activation in targets. Interestingly, CD56 expression was found to be reduced in breast tumor tissues (36%) with strong inter- and intratumoral heterogeneity in comparison to normal breast tissues (80%). CD56 is a potential predictive biomarker for BC responsiveness to NK-92-cell based immunotherapy and loss of CD56 expression might be a mechanism of escape from NK-immunity.

CAR T Cell Therapy for Neuroblastoma

Patients with high risk neuroblastoma have a poor prognosis and survivors are often left with debilitating long term sequelae from treatment. Even after integration of anti-GD2 monoclonal antibody therapy into standard, upftont protocols, 5-year overall survival rates are only about 50%. The success of anti-GD2 therapy has proven that immunotherapy can be effective in neuroblastoma. Adoptive transfer of chimeric antigen receptor (CAR) T cells has the potential to build on this success. In early phase clinical trials, CAR T cell therapy for neuroblastoma has proven safe and feasible, but significant barriers to efficacy remain. These include lack of T cell persistence and potency, difficulty in target identification, and an immunosuppressive tumor microenvironment. With recent advances in CAR T cell engineering, many of these issues are being addressed in the laboratory. In this review, we summarize the clinical trials that have been completed or are underway for CAR T cell therapy in neuroblastoma, discuss the conclusions and open questions derived from these trials, and consider potential strategies to improve CAR T cell therapy for patients with neuroblastoma.

Immunohistochemical Biomarkers of Gastrointestinal, Pancreatic, Pulmonary, and Thymic Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) are a heterogeneous group of epithelial neoplastic proliferations that irrespective of their primary site share features of neural and endocrine differentiation including the presence of secretory granules, synaptic-like vesicles, and the ability to produce amine and/or peptide hormones. NENs encompass a wide spectrum of neoplasms ranging from well-differentiated indolent tumors to highly aggressive poorly differentiated neuroendocrine carcinomas. Most cases arise in the digestive system and in thoracic organs, i.e., the lung and thymus. A correct diagnostic approach is crucial for the management of patients with both digestive and thoracic NENs, because their high clinical and biological heterogeneity is related to their prognosis and response to therapy. In this context, immunohistochemistry represents an indispensable diagnostic tool that pathologists need to use for the correct diagnosis and classification of such neoplasms. In addition, immunohistochemistry is also useful in identifying prognostic and theranostic markers. In the present article, the authors will review the role of immunohistochemistry in the routine workup of digestive and thoracic NENs.

PEGylated dendritic polyglycerol conjugate targeting NCAM-expressing neuroblastoma: Limitations and challenges

Neural cell adhesion molecule (NCAM) is found to be a stem-cell marker in several tumor types and its overexpression is known to correlate with increased metastatic capacity. To combine extravasation- and ligand-dependent targeting to NCAM overexpressing-cells in the tumor microenvironment, we developed a PEGylated NCAM-targeted dendritic polyglycerol (PG) conjugate. Here, we describe the synthesis, physico-chemical characterization and biological evaluation of a PG conjugate bearing the mitotic inhibitor paclitaxel (PTX) and an NCAM-targeting peptide (NTP). PG-NTP-PTX-PEG was evaluated for its ability to inhibit neuroblastoma progression in vitro and in vivo as compared to non-targeted derivatives and free drug. NCAM-targeted conjugate inhibited the migration of proliferating endothelial cells, suggesting it would be able to inhibit tumor angiogenesis. The targeting conjugate provided an improved binding and uptake on IMR-32 cells compared to non-targeted control. However, these results did not translate to our in vivo model on orthotopic neuroblastoma bearing mice.

Inhibition of cathepsin proteases attenuates migration and sensitizes aggressive N-Myc amplified human neuroblastoma cells to doxorubicin

Neuroblastoma arises from the sympathetic nervous system and accounts for 15% of childhood cancer mortality. Amplification of the oncogene N-Myc is reported to occur in more than 20% of patients. While N-Myc amplification status strongly correlates with higher tumour aggression and resistance to treatment, the role of N-Myc in the aggressive progression of the disease is poorly understood. N-Myc being a transcription factor can modulate the secretion of key proteins that may play a pivotal role in tumorigenesis. Characterising the soluble secreted proteins or secretome will aid in understanding their role in the tumour microenvironment, such as promoting cancer cell invasion and resistance to treatment. The aim of this study is to characterise the secretome of human malignant neuroblastoma SK-N-BE2 (N-Myc amplified, more aggressive) and SH-SY5Y (N-Myc non-amplified, less aggressive) cells. Conditioned media from SK-N-BE2 and SH-SY5Y cell lines were subjected to proteomics analysis. We report a catalogue of 894 proteins identified in the secretome isolated from the two neuroblastoma cell lines, SK-N-BE2 and SH-SY5Y. Functional enrichment analysis using FunRich software identified enhanced secretion of proteins implicated in cysteine peptidase activity in the aggressive N-Myc amplified SK-N-BE2 secretome compared to the less tumorigenic SH-SY5Y cells. Protein-protein interaction-based network analysis highlighted the enrichment of cathepsin and epithelial-to-mesenchymal transition sub-networks. For the first time, inhibition of cathepsins by inhibitors sensitized the resistant SK-N-BE2 cells to doxorubicin as well as decreased its migratory potential. The dataset of secretome proteins of N-Myc amplified (more aggressive) and non-amplified (less aggressive) neuroblastoma cells represent the first inventory of neuroblastoma secretome. The study also highlights the prominent role of cathepsins in the N-Myc amplified neuroblastoma pathogenesis. As N-Myc amplification correlates with aggressive neuroblastoma and chemotherapy-based treatment failure, co-treatment with cathepsin inhibitors might be a better avenue for disease management.

Differential killing of CD56-expressing cells by drug-conjugated human antibodies targeting membrane-distal and membrane-proximal non-overlapping epitopes

CD56 (NCAM, neural cell adhesion molecule) is over-expressed in many tumor types, including neuroblastoma, multiple myeloma, small cell lung cancer, ovarian cancer, acute myeloid leukemia, NK-T lymphoma, neuroendocrine cancer and pancreatic cancer. Using phage display, we identified 2 high-affinity anti-CD56 human monoclonal antibodies (mAbs), m900 and m906, which bound to spatially separated non-overlapping epitopes with similar affinity (equilibrium dissociation constant 2.9 and 4.5 nM, respectively). m900 bound to the membrane proximal fibronectin type III-like domains, whereas m906 bound to the N-terminal IgG-like domains. m906 induced significant down-regulation of CD56 in 4 neuroblastoma cell lines tested, while m900-induced downregulation of CD56 was much lower. Antibody-drug conjugates (ADCs) made by conjugation with a highly potent pyrrolobenzodiazepine dimer (PBD) exhibited killing activity that correlated with CD56 down-regulation, and to some extent with in vivo binding ability of the antibodies. The m906PBD ADC was much more potent than m900PBD, likely due to higher CD56-mediated downregulation and stronger binding to cells. Treatment with m906PBD ADC resulted in very potent cytotoxicity (IC50: 0.05-1.7 pM). These results suggest a novel approach for targeting CD56-expressing neuroblastoma cells. Further studies in animal models and in humans are needed to find whether these antibodies and their drug conjugates are promising candidate therapeutics.

Comparison of L1 expression and secretion in glioblastoma and neuroblastoma cells

The expression of cell adhesion molecule L1 has been identified in a vast spectrum of tumors; however, its expression pattern with regard to tumor type is rarely discussed. In the present study, we studied L1 levels in human glioblastomas and neuroblastomas, and compared the expression and secretion of L1 in human glioblastoma U87-MG and neuroblastoma SK-N-SH cells. Immunofluorescence staining revealed different grades of L1 staining in human glioblastoma and neuroblastoma samples. In U87-MG cells, full-length L1 was weakly detected in cell lysates (CLs), while greater levels of abundant soluble L1 were confined in conditioned culture medium (CCM). In contrast, higher levels of full-length L1 were confined in SK-N-SH CLs, while almost no soluble forms of L1 were detected in CCM. Our data indicates various expression patterns of L1 in U87-MG and SK-N-SH cells, which may underlie the different malignancies of the two neural tumor types and further stress the importance of soluble L1-mediated signaling pathways in cell malignancy.

Bone marrow-infiltrating human neuroblastoma cells express high levels of calprotectin and HLA-G proteins

Metastases in the bone marrow (BM) are grim prognostic factors in patients with neuroblastoma (NB). In spite of extensive analysis of primary tumor cells from high- and low-risk NB patients, a characterization of freshly isolated BM-infiltrating metastatic NB cells is still lacking. Our aim was to identify proteins specifically expressed by metastatic NB cells, that may be relevant for prognostic and therapeutic purposes. Sixty-six Italian children over 18 months of age, diagnosed with stage 4 NB, were included in the study. Metastatic NB cells were freshly isolated from patients' BM by positive immunomagnetic bead manipulation using anti-GD2 monoclonal antibody. Gene expression profiles were compared with those obtained from archived NB primary tumors from patients with 5 y-follow-up. After validation by RT-qPCR, expression/secretion of the proteins encoded by the up-regulated genes in the BM-infiltrating NB cells was evaluated by flow cytometry and ELISA. Compared to primary tumor cells, BM-infiltrating NB cells down-modulated the expression of CX3CL1, AGT, ATP1A2 mRNAs, whereas they up-regulated several genes commonly expressed by various lineages of BM resident cells. BM-infiltrating NB cells expressed indeed the proteins encoded by the top-ranked genes, S100A8 and A9 (calprotectin), CD177 and CD3, and secreted the CXCL7 chemokine. BM-infiltrating NB cells also expressed CD271 and HLA-G. We have identified proteins specifically expressed by BM-infiltrating NB cells. Among them, calprotectin, a potent inflammatory protein, and HLA-G, endowed with tolerogenic properties facilitating tumor escape from host immune response, may represent novel biomarkers and/or targets for therapeutic intervention in high-risk NB patients.

Eliciting carbohydrate-specific immune response against sialosides: success and challenges

Chemoenzymatic synthesis has been shown to be a powerful adjunct to carbohydrate chemistry since it allows chemists to prepare a wide range of complex carbohydrate analogs in large amounts and with unparalleled efficiency. Here we summarize investigations conducted in our group into the synthesis and immunochemistry of tumor-associated gangliosides and the development of a chemoenzymatic route to α(2→8)-linked oligosialosides by probing substrate binding to the enzyme, α(2→8)-sialyltransferase.

Oct-4+/Tenascin C+ neuroblastoma cells serve as progenitors of tumor-derived endothelial cells

Neuroblastoma (NB)-associated endothelial microvessels (EMs) may be lined by tumor-derived endothelial cells (TECs), that are genetically unstable and chemoresistant. Here we have addressed the identification of TEC progenitors in NB by focusing on Octamer-binding transcription factor 4 (Oct-4) as a putative marker. Oct-4(+) cells were detected in primary NB samples (n = 23), metastatic bone marrow aspirates (n = 10), NB cell lines (n = 4), and orthotopic tumors (n = 10) formed by the HTLA-230 NB cell line in immunodeficient mice. Most Oct-4(+) cells showed a perivascular distribution, with 5% of them homing in perinecrotic areas. All Oct-4(+) cells were tumor-derived since they shared amplification of MYCN oncogene with malignant cells. Perivascular Oct-4(+) cells expressed stem cell-related, neural progenitor-related and NB-related markers, including surface Tenascin C (TNC), that was absent from perinecrotic Oct-4(+) cells and bulk tumor cells. TNC(+) but not TNC(-) HTLA-230 cells differentiated in vitro into endothelial-like cells expressing vascular-endothelial-cadherin, prostate-specific membrane antigen and CD31 upon culture in medium containing vascular endothelial growth factor (VEGF). TNC(+) but not TNC(-) HTLA-230 cells formed neurospheres when cultured in serum-free medium. Both cell fractions were tumorigenic, but only tumors formed by TNC(+) cells contained EMs lined by TECs. In conclusion, we have identified in NB tumors two putative niches containing Oct-4(+) tumor cells. Oct-4(+)/TNC(+) perivascular NB cells displayed a high degree of plasticity and served as progenitors of TECs. Therapeutic targeting of Oct4(+)/TNC(+) progenitors may counteract the contribution of NB-derived ECs to tumor relapse and chemoresistance.

Immunohistochemistry in diagnosis of soft tissue tumours

Immunohistochemistry in soft tissue tumours, and especially sarcomas, is used to identify differentiation in the neoplastic cells. In some cases, specific antigens are expressed; however, an initial panel of antibodies is often required in order to establish the broad lineage, with a subsequent, more focused, panel to allow classification. Immunohistochemical evaluation must be employed with the clinical picture, the morphology, and, when necessary, other ancillary techniques such as molecular genetics and cytogenetics. Whereas some diagnoses are evident on morphology, many soft tissue neoplasms are seen microscopically as spindle cell, epithelioid cell, small round cell or pleomorphic tumours that need to be further characterized. This article reviews selected applications of immunohistochemistry in the diagnosis of each of the principal morphological groups, concentrating on areas of most use in daily practice.