Reduced frequency of cytotoxic CD56dim CD16+ NK cells leads to impaired antibody-dependent degranulation in EBV-positive classical Hodgkin lymphoma.

Around 30-50% of classical Hodgkin lymphoma (cHL) cases in immunocompetent individuals from industrialized countries are associated with the B-lymphotropic Epstein-Barr virus (EBV). Although natural killer (NK) cells exhibit anti-viral and anti-tumoral functions, virtually nothing is known about quantitative and qualitative differences in NK cells in patients with EBV+ cHL vs. EBV- cHL. Here, we prospectively investigated 36 cHL patients without known immune suppression or overt immunodeficiency at diagnosis. All 10 EBV+ cHL patients and 25 out 26 EBV- cHL were seropositive for EBV antibodies, and EBV+ cHL patients presented with higher plasma EBV DNA levels compared to EBV- cHL patients. We show that the CD56dim CD16+ NK cell subset was decreased in frequency in EBV+ cHL patients compared to EBV- cHL patients. This quantitative deficiency translates into an impaired CD56dim NK cell mediated degranulation toward rituximab-coated HLA class 1 negative lymphoblastoid cells in EBV+ compared to EBV- cHL patients. We finally observed a trend to a decrease in the rituximab-associated degranulation and ADCC of in vitro expanded NK cells of EBV+ cHL compared to healthy controls. Our findings may impact on the design of adjunctive treatment targeting antibody-dependent cellular cytotoxicity in EBV+ cHL.

Aberrant myelomonocytic CD56 expression in Down syndrome is frequent and not associated with leukemogenesis.

Children with Down syndrome (DS) are at an increased risk of developing transient abnormal myelopoiesis (TAM) and acute leukemia. Aberrant expression of CD56 has been observed on myeloid leukemic blasts in DS patients. In general, CD56 expression in acute myeloid leukemia (AML) is considered a promoter of leukemogenesis. We did a retrospective flow cytometric study to investigate mature myelomonocytic cell CD56 expression patterns in TAM, non-TAM, and leukemia cases with DS. Flow cytometric analysis showed that granulocyte and monocyte aberrant/dysplastic CD56 expression is an inherent characteristic of most DS patients irrespective of the presence of TAM or leukemia. Increased CD56 expression in monocyte and granulocyte populations in DS could be multifactorial; greater expression of RUNX1 secondary to the gene dose effect of trisomy 21 along with the maturational state of the cells are the potential contributors. Unlike AML seen in non-DS patients, CD56 overexpression in DS AML cases does not appear to play a role in leukemogenesis.

Cytogenetics and FISH negative cryptic acute promyelocytic leukemia with CD56 expression.

Acute promyelocytic leukemia (APL) is characterized by reciprocal translocation t(15;17)(q22;q21) and has a favorable prognosis upon immediate recognition and treatment. However, rare cases of APL show a cryptic insertion of retinoic acid receptor alpha (RARA) gene into promyelocytic leukemia (PML) gene which is negative both by fluorescence in situ hybridization (FISH) and conventional cytogenetics (CC). Morphology, cytochemistry and flow cytometry play a key role in early identification of such cases. Polymerase chain reaction (PCR) remains the most efficient diagnostic modality for detection of cryptic APL and other variants. It is important to identify these cases as they show beneficial response to retinoids and favourable prognosis. We herein present a rare case of cryptic APL negative by FISH and conventional cytogenetics but positive for PML-RARA by PCR.

Rs-1884444 G/T variant in IL-23 receptor is likely to modify risk of bladder urothelial carcinoma by regulating IL-23/IL-17 inflammatory pathway.

Bladder urothelial carcinoma (BUC) is a chronic relapsing urological malignancy, which poses a serious threat to human life. Non-resolving chronic-inflammation at the neoplastic site is associated consistently with inducing tumor-progression and poor patient outcomes. Interleukin 23 receptor (IL-23R) is a key element in T-helper 17 cell-mediated inflammatory process, that plays a critical role in orchestrating tumor-promoting inflammation. Therefore, we hypothesized that potentially functional genetic variant rs1884444 G/T of IL-23R may modify BUC risk. To validate this hypothesis, our findings demonstrated that the rs1884444 G/T variant was significantly associated with a reduced risk of BUC compared to controls observed under allelic (T vs. G) and dominant (GT + TT vs. GG) models (P < 0.05). In addition, the frequency of the T-allele has dropped to very low values in the case of high-grades and invasive-tumors (P < 0.05). Thus, T-allele has emerged as a reliable genetic marker for good prognosis of BUC. In tumorgenesis, the binding-affinity of the receptor seemed to be distorted by the effect of the non-conservative G/T variation, which in turn caused the IL-23/IL-17 pathway to be disabled. This was recognized by low levels of IL-23 and IL-17 in the serum of patients, under the influence of all the tested genetic models (P < 0.01). Results also indicated that the level of the receptor-bearing immune cells could be altered in response to the G/T protective effect. For example, the median counts of T-helper CD4+ cells and CD56+ natural killers increased significantly in conjunction with the decrease in the median count of CD14+ tumor-associated-macrophages under the dominant model. Nevertheless, the causative link between this subtle polymorphism and the immune-surveillance against BUC needs further in-depth investigation. Overall, we concluded that the rs-1884444 G/T variant is highly-associated with a reduction in the BUC risk, which may occur via deregulation of the IL-23/IL-17 pathway.

Biological properties of bone marrow plasma cells influence their recovery in aspirate specimens: impact on classification of plasma cell disorders and potential bias to evaluation of treatment response.

Methods to estimate bone marrow plasma cells (BMPC) basically include histopathology, cytomorphology, and flow cytometry. The present study compares the outcomes of these methods with special focus on the impact of BMPC-specific characteristics on their recovery by either method. Laboratory reports of diagnostic samples from 238 consecutive patients with suspected or known plasma cell disease were retrospectively analyzed. The median (IQR) proportion of BMPC was 30.0% (15.0-70.0%) by histological review (hBMPC), 7.0% (2.0-16.0%) by smear review (sBMPC), and 3.0% (0.8-10.0%) by flow cytometry (fBMPC). The disparity of results between core biopsy and aspirate smear was enhanced in case of poor quality of the smear, increased BM fiber content, higher grade cell atypia, expression of CD56 (all P < 0.0001), the number of cytogenetic aberrations (P = 0.0002), and abnormalities of the MYC gene (P = 0.0002). Conversely, expression of CD19 and a non-clonal plasma cell phenotype were associated with a lower difference between hBMPC and sBMPC (both P < 0.0001). The disparity between the percentages of sBMPC and fBMPC was associated with the quality of the smear (P = 0.0007) and expression of CD56 (P < 0.0001). Our results suggest that the recovery of BMPC in aspirate specimens not only is a matter of sampling quality but also depends on biological cell properties. Aspiration failure due to malignant type features of BMPC may lead to misclassification of plasma cell disorders and represent a bias for the detection of minimal residual disease after therapy.

Expression of novel neuroendocrine marker insulinoma-associated protein 1 (INSM1) in genitourinary high-grade neuroendocrine carcinomas: An immunohistochemical study with specificity analysis and comparison to chromogranin, synaptophysin, and CD56.

Confirmation of genitourinary high-grade neuroendocrine carcinomas (GU-HGNECs) often requires immunohistochemical staining. Here we evaluated a novel neuroendocrine marker, insulinoma-associated protein 1 (INSM1), in GU-HGNECs with comparison to chromogranin, synaptophysin and CD56. Immunohistochemical expression of INSM1, chromogranin, synaptophysin, and CD56 was evaluated in 39 GU-HGNECs using full tissue sections [4 in kidney, 28 in urinary bladder, and 7 in prostate; 31 small cell carcinomas (SmCCs), 6 large cell neuroendocrine carcinomas (LCNECs), 2 mixed SmCC-LCNECs]. In 33 SmCCs/components, INSM1 showed similar sensitivity (93.9 %) to chromogranin (87.8 %), synaptophysin (93.9 %) and CD56 (87.8 %), and stained a similar percentage of tumor cells (52 %) to chromogranin (49 %) and CD56 (52 %), but lower than synaptophysin (87 %) (p < 0.0001). In 8 LCNECs/components, INSM1 is similar to chromogranin, synaptophysin or CD56 in sensitivity (62.5 %, 62.5 %, 75 %, 62.5 %, respectively) and the mean percentage of positively stained tumor cells (21 %, 44 %, 48 %, 37 %, respectively). INSM1 is more sensitive for SmCCs than LCNECs (93.9 % vs. 62.5 %, p = 0.015). INSM1 showed 97.4 % specificity upon analyzing 273 genitourinary non-neuroendocrine tumors on tissue microarrays. Our study indicates that INSM1 is a sensitive marker for genitourinary HGNECs with high specificity. For genitourinary SmCCs, INSM1 shows similar sensitivity to chromogranin, synaptophysin and CD56 but stains a lower percentage of tumor cells than synaptophysin. For genitourinary LCNECs, INSM1 showed similar sensitivity to chromogranin, synaptophysin and CD56. INSM1 is more sensitive for genitourinary SmCCs than LCNECs. Our result and literature review indicate that whether INSM1 is more sensitive than conventional neuroendocrine markers for HGNECs depends on the tumor primary sites.

Insulinoma-associated Protein 1 (INSM1) in Thoracic Tumors is Less Sensitive but More Specific Compared With Synaptophysin, Chromogranin A, and CD56.

OBJECTIVE: Recognition of neuroendocrine differentiation is important for tumor classification and treatment stratification. To detect and confirm neuroendocrine differentiation, a combination of morphology and immunohistochemistry is often required. In this regard, synaptophysin, chromogranin A, and CD56 are established immunohistochemical markers. Insulinoma-associated protein 1 (INSM1) has been suggested as a novel stand-alone marker with the potential to replace the current standard panel. In this study, we compared the sensitivity and specificity of INSM1 and established markers. MATERIALS AND METHODS: A cohort of 493 lung tumors including 112 typical, 39 atypical carcinoids, 77 large cell neuroendocrine carcinomas, 144 small cell lung cancers, 30 thoracic paragangliomas, 47 adenocarcinomas, and 44 squamous cell carcinomas were selected and tissue microarrays were constructed. Synaptophysin, chromogranin A, CD56, and INSM1 were stained on all cases and evaluated manually as well as with an analysis software. Positivity was defined as ≥1% stained tumor cells in at least 1 of 2 cores per patient. RESULTS: INSM1 was positive in 305 of 402 tumors with expected neuroendocrine differentiation (typical and atypical carcinoids, large cell neuroendocrine carcinomas, small cell lung cancers, and paraganglioma; sensitivity: 76%). INSM1 was negative in all but 1 of 91 analyzed non-neuroendocrine tumors (adenocarcinomas, squamous cell carcinomas; specificity: 99%). All conventional markers, as well as their combination, had a higher sensitivity (97%) and a lower specificity (78%) for neuroendocrine differentiation compared with INSM1. CONCLUSIONS: Although INSM1 might be a meaningful adjunct in the differential diagnosis of neuroendocrine neoplasias, a general uncritical vote for replacing the traditional markers by INSM1 may not be justified.

Expression of HBME-1 and CD56 in follicular variant of papillary carcinoma in children: An immunohistochemical study and their diagnostic utility.

Papillary thyroid carcinoma (PTC) is the most common differentiated thyroid cancer in children; and the follicular variant is the second most common variant after the classic subtype. The histological appearance of follicular variant of papillary thyroid cancer (FVPTC), can be mimicked by benign follicular nodules. Pediatric pathologists encountering such lesions with FVPTC-like appearance may err on diagnosing the benign lesions as malignant. In adult patients, several immunohistochemical markers have emerged recently as a useful adjunct to distinguish differentiated thyroid carcinomas from benign follicular lesions. We undertook an inter-institutional retrospective study to establish the diagnostic utility of immunohistochemical staining for HBME-1, Galectin-3 and CD56 in differentiating FVPTC from its benign mimics, follicular adenoma and adenomatoid nodules, in children. Our specific aim of the project was to define the sensitivity and specificity of the three antibodies in FVPTC. Based on institutional diagnoses, a total of 66 cases were obtained: 32 FVPTC and 34 benign follicular nodules that comprised of 23 follicular adenoma and 11 adenomatoid nodules. Five investigators, who were blinded to the original diagnoses, independently reviewed the slides following pre-determined criteria and semi-quantitatively scoring the immunohistochemical staining. The immunohistochemical staining revealed that a combination of positive HBME-1 and negative CD56 result gave 100% specificity and positive predictive value in distinguishing FVPTC from benign follicular nodules. However, the antibody combination suffered from a lower sensitivity (50%). We used a cutoff of 25% positivity of tumor cells in determining positivity of tumor cells to an antibody. In conclusion, our study found a very high specificity and strong positive predictive value for the combination of HBME-1 and CD56 immunohistochemical stains in distinguishing FVPTC from benign follicular lesions.

Gene and protein expression of E-cadherin and NCAM markers in non-functioning pituitary adenomas.

Non-functioning pituitary adenomas (NFPA) are classified as benign tumors of slow growth, but 40% of them present local invasion, a characteristic of behavior still unpredictable with the use of current tumor markers. This work aims to evaluate the tissue markers E-cadherin and NCAM, which act on cell adhesion, in tumor tissue samples of NFPA and its relationship with the degree of local invasiveness. Gene expression of E-cadherin (CDH1) and NCAM (NCAM1) was assessed by real-time PCR and tissue expression by immunohistochemistry. Fifty-three patients with macroadenomas were submitted to transsphenoidal surgery, presented grade II invasive adenomas in 16 cases (30.2%), grade III in 7 (13.2%) and grade IV in 30 (56.6%). In the immunohistochemistry, one case was negative for E-cadherin, 7 showed weak immunostaining, 17 moderate and 28 strong, whereas for NCAM, 5 showed negative, 28 weakly, 14 moderate and 6 strong. Regarding gene expression, 43.3% showed expression for CDH1 (mean of 2.12) and 50% for NCAM1 (mean of 1.86). There was no significant correlation between the immunohistochemical expression of the markers, as well as the gene expression, the degree of invasiveness and clinical data. The results suggest that E-cadherin and NCAM markers are not directly related to the invasiveness in NFPA.

Diagnostic value of HBME-1, CK19, Galectin 3, and CD56 in the subtypes of follicular variant of papillary thyroid carcinoma.

Our aim is to explore differences in Hector Battifora mesothelial-1 (HBME-1), cytokeratin-19 (CK19), Galectin-3 (Gal-3), and CD56 expression in infiltrative follicular variants of papillary carcinoma (IFVPTC) and encapsulated follicular variants of papillary carcinoma (EFVPTC) and to provide clues for distinguishing the two subtypes preoperatively. Tissue microarrays from 100 EFVPTC (45 non-invasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) and 55 invasive EFVPTCs), 43 IFVPTCs, and 64 follicular neoplasms (FN) were immunostained with HBME-1, CK19, Gal-3, and CD56. Each case was scored 1 point for every positive result. Immunohistochemical expression was not significantly different in invasive EFVPTC and NIFTP, except for that of HBME-1. HBME-1, CK19, Gal-3, and CD56 expression were significantly higher in IFVPTC than in EFVPTC. At the cutoff of 3 points, the score method had special diagnostic value for differentiating IFVPTC from EFVPTC and FN and for predicting lymph node metastasis. Scoring of immunohistochemistry results may be applied to core biopsy or cell blocks to assist ultrasonographic, cytologic and molecular tests in differentiating IFVPTC and EFVPTC preoperatively, possibly appropriately guiding EFVPTC preoperatively for limited operation or active surveillance.

CD56 expression in benign and malignant thyroid lesions.

INTRODUCTION: Thyroid cancer is the most common endocrine malignancy with more than 95% originating from follicular epithelial cells. Diagnostic dilemma may arise in occasional cases such as when an encapsulated nodule with a follicular growth pattern exhibits clear nuclei with grooves making it difficult to distinguish a follicular adenoma from encapsulated follicular variant papillary thyroid carcinoma. This study aimed to evaluate the diagnostic utility of an immunohistochemical marker, CD56, to distinguish between benign and malignant thyroid lesions. MATERIALS AND METHODS: We retrospectively studied CD56 expression in 54 benign and 54 malignant thyroid lesions using archival formalin fixed paraffin-embedded tissue blocks for the study period from January 2010 to December 2015, diagnosed in a tertiary hospital. RESULTS: CD56 was expressed in 52/54 (96.3%) of benign specimens and only 24/54 (44.4%) of malignant ones. The malignant specimens comprised 31 (57.4%) papillary thyroid carcinomas (PTC), 11 (20.3%) follicular carcinomas (FC), seven (13%) medullary thyroid carcinomas (MC), one (1.9%) poorly differentiated carcinoma (PC) and four (7.4%) anaplastic carcinomas (AC). CD56 was not expressed in 28/31 (90.3%) of the PTCs, 1/11 (9.1%) FCs, 1/4 (25%) of ACs while all MCs and the PD were positive. The benign group comprised nodular hyperplasias (29/54), lymphocytic thyroiditis (10/54), follicular adenomas (FA) (14/54) and one hyalinising trabecular tumour. CD56 was expressed in all the benign cases except one FA and one nodular hyperplasia. Thirteen of the 14 FAs were CD56 positive. The difference in expression between benign and malignant tumours was statistically significant as the p value was <0.01. CONCLUSION: CD56 is a potentially good immunohistochemical marker for differentiating papillary thyroid carcinoma from other benign follicular lesions of the thyroid especially in differentiating follicular variant PTC from FA in equivocal cases.

Pediatric CD8+/CD56+ mycosis fungoides with cytotoxic marker expression: A variant with indolent course.

Mycosis fungoides is predominantly a disease of older patients, but occasionally occurs in children. We report a rare case of CD8+/CD56+ mycosis fungoides with cytotoxic marker (perforin, TIA-1, and granzyme B) expression in a 10-year-old boy. Disease presented with three asymptomatic, slowly progressive erythematous and scaling plaques, surrounded by hypochromic alone in the left tight and lower trunk. UVB narrow band associated with topical corticosteroids resulted in complete remission in about 2 months, and no recurrence at 2-year follow-up. Three similar cases have been retrieved in children through PubMed search, showing similar clinical presentation with erythematous scaling lesions, good response to skin-directed treatments and a favorable prognosis.

The diagnostic value of TROP-2, SLP-2 and CD56 expression in papillary thyroid carcinoma.

OBJECTIVE: The study aimed to explore some novel diagnostic biomarkers for papillary thyroid carcinoma (PTC) by identifying the different expression of TROP-2, SLP-2 and CD56 in benign and malignant thyroid lesions. METHODS: We evaluated the mRNA expressions of TROP-2 and SLP-2 in fine needle aspirates (FNAs) which contained 10 PTCs and 10 benign follicular adenomas (FAs) using quantitative real-time PCR (qRT-PCR). Immunohistochemical (IHC) staining of TROP-2, SLP-2 and CD56 was also performed on postoperative samples of 30 PTCs and 29 FAs. Membranous or cytoplasmic staining in > 10% of cells was considered as positive. Diagnostic sensitivity, specificity, positive predictive value, negative predictive value (NPV) and diagnostic accuracy of these three biomarkers were carried out. We further analyzed the associations between the clinical features and the expressions of markers in PTCs. RESULTS: The mRNA expressions of both TROP-2 and SLP-2 were increased substantially in PTCs in comparison with those in FAs (P < 0.05). Similarly, IHC for these two proteins demonstrated higher positive staining in PTCs than in FAs (96.5% vs. 12.5% for TROP-2, 83.3% vs. 20.7% for SLP-2, P < 0.05). Conversely, CD56 expression was lost with 86.7% of PTCs. In identifying malignancy, TROP-2 was the most sensitive marker and CD56 was the most specific one. When the markers were combined, the sensitivity and NPV increased to 100% and had better diagnostic accuracy. However, no association was found between biomarker expressions and clinicopathological factors in PTCs. CONCLUSIONS: We found that TROP-2, SLP-2 and CD56 were effective diagnostic markers for PTC, especially when they were combined to use.

Low expression of neural cell adhesion molecule, CD56, is associated with low efficacy of bortezomib plus dexamethasone therapy in multiple myeloma.

Bortezomib (Btz) is an active agent used to treat multiple myeloma (MM). Not all patients who receive Btz-containing therapy show a favorable response. Interaction of cellular adhesion molecules with MM and bone marrow stromal cells is crucial for the survival of MM cells. However, little is known about the role of these molecules in the sensitivity of MM to Btz-containing therapy. Thus, we evaluated the correlation between the level of cellular adhesion molecules in MM cells and the efficacy of Btz plus dexamethasone (Bd) therapy. The expression of the neural cell adhesion molecule gene (NCAM, also known as CD56), ITGA4, CXCR4, and other genes were analyzed in 74 samples of primary MM cells collected from patients before they received Bd therapy. Of the eight genes tested, expression of NCAM was lower among patients who responded poorly to Bd therapy. In vitro expression of NCAM induced by transfection of MM cells enhanced their sensitivity to Btz treatment by causing accumulation of polyubiquitinated proteins. Our results indicate that expression of NCAM is associated with better response to Btz treatment and is a promising candidate biomarker for predicting response to therapies involving Btz.

Decreased CD122 on CD56dim NK associated with its impairment in asymptomatic chronic HBV carriers with high levels of HBV DNA, HBsAg and HBeAg.

AIMS: NK cells play important roles in inhibiting HBV replication and preventing HBV infection. However, NK-cell dysfunction has not been fully studied in asymptomatic chronic HBV carriers (ASC). This study aims to assess decreased expression of CD122 associated with impaired NK cells and the restoration of NK cells with IL-2 and IL-15 stimulation. MAIN METHODS: The experiments were performed by flow cytometer, cytotoxicity assay, ELISA and western blotting. KEY FINDINGS: The reduced CD122 on CD56+ NK cells and CD56dim NK cells is associated with high levels of HBV DNA, HBsAg or HBeAg in ASCs, in which CD56dim NK-cell impairment is observed. Moreover, decreased IFN-γ and degranulation and low cytotoxicity by CD56dim NK cells after CD122 blockade were revealed. IL-2 and/or IL-15 can restore impaired CD56dim NK cells, together with increased p-STAT5, which can be reversed by CD122 blockade. Additionally, IL-2 or IL-15 can enhance IFN-α2-activated CD56dim NK-cell immune responses via up-regulating interferon alpha and beta receptor subunit 2 (IFNAR2). SIGNIFICANCE: Down-regulated CD122 on CD56dim NK cell in ASCs with massive viral antigens and high viremia is associated with its impairment, which can be restored by IL-2 and/or IL-15, or combined with IFN-α2.

NCAM1 is the Target of miRNA-572: Validation in the Human Oligodendroglial Cell Line.

The neural cell adhesion molecule 1 (NCAM1) is a fundamental protein in cell-cell interaction and in cellular developmental processes, and its dysregulation is involved in a number of diseases including multiple sclerosis. Studies in rats suggest that the modulation of NCAM1 expression is regulated by miRNA-572, but no data are available confirming such interaction in the human system. We analyzed whether this is the case using a human oligodendroglial cell line (MO3.13). MO3.13 cells were transfected with miRNA-572 mimic and inhibitor separately; NCAM1 mRNA and protein expression levels were analyzed at different time points after transfection. Results indicated that NCAM1 expression is increased after transfection with miRNA-572 inhibitor, whereas it is decreased after transfection with the mimic (p < 0.005). The interaction between NCAM1 and miRNA-572 was subsequently confirmed in a Vero cell line that does not express NCAM1, by luciferase assay after transfection with NCAM1. These results confirm that miRNA-572 regulates NCAM1 and for the first time demonstrate that this interaction regulates NCAM1 expression in human cells. Data herein also support the hypothesis that miRNA-572 is involved in diseases associated with NCAM1 deregulation, suggesting its possible use as a biomarker in these diseases.

Prognostic impact of CD200 and CD56 expression in pediatric B-cell acute lymphoblastic leukemia patients.

This study aimed to determine the prognostic impact of CD200 and CD56 expression in pediatric B cell acute lymphoblastic leukemia (B-ALL) patients, both of which have been implicated in immune tolerance and previously suggested as independent risk factors. CD200 has a central role in immune tolerance that protects stem cells and other critical tissues from immune damage. The expression of CD200/CD56 in leukemic blasts were assessed in leukemic blasts before chemotherapy in 43 bone marrow (BM) and/or peripheral blood (PB) samples by flow cytometry. Twenty eight of 43 B-ALL cases (65%) showed CD200 positive expression, 5 of 43 cases (11.6%) showed CD56 expression, and only 2 patients (4.7%) expressed both CD200 and CD56. Patients with CD200+ and CD56+ were significantly associated with lower platelet count; less tendency for induction of remission response as compared to negative ones (p = .01 for both). The overall survival (OS) and DFS were significantly shorter in CD200+ and CD56+ cases as compared to those with CD200- and CD56- expression. In conclusion, CD200 and/or CD56 positive expression in B-ALL at diagnosis suggest a poor prognosis and may be associated with biological aggressiveness.

Polysialylation at Early Stages of Oligodendrocyte Differentiation Promotes Myelin Repair.

Polysialic acid is a glycan modification of the neural cell adhesion molecule (NCAM) produced by the polysialyltransferases ST8SIA2 and ST8SIA4. Polysialic acid has been detected in multiple sclerosis plaques, but its beneficial or adverse role in remyelination is elusive. Here, we show that, despite a developmental delay, myelination at the onset and during cuprizone-induced demyelination was unaffected in male Ncam1-/- or St8sia2-/- mice. However, remyelination, restoration of oligodendrocyte densities, and motor recovery after the cessation of cuprizone treatment were compromised. Impaired differentiation of NCAM- or ST8SIA2-negative oligodendrocyte precursors suggested an underlying cell-autonomous mechanism. In contrast, premature differentiation in ST8SIA4-negative cultures explained the accelerated remyelination previously observed in St8sia4-/- mice. mRNA profiling during differentiation of human stem cell-derived and primary murine oligodendrocytes indicated that the opposing roles of ST8SIA2 and ST8SIA4 arise from sequential expression. We also provide evidence that potentiation of ST8SIA2 by 9-cis-retinoic acid and artificial polysialylation of oligodendrocyte precursors by a bacterial polysialyltransferase are mechanisms to promote oligodendrocytic differentiation. Thus, differential targeting of polysialyltransferases and polysialic acid engineering are promising strategies to advance the treatment of demyelinating diseases.SIGNIFICANCE STATEMENT The beneficial or adverse role of polysialic acid (polySia) in myelin repair is a long-standing question. As a modification of the neural cell adhesion molecule (NCAM), polySia is produced by the polysialyltransferases ST8SIA2 and ST8SIA4. Here we demonstrate that NCAM and ST8SIA2 promote oligodendrocyte differentiation and myelin repair as well as motor recovery after cuprizone-induced demyelination. In contrast, ST8SIA4 delays oligodendrocyte differentiation, explaining its adverse role in remyelination. These opposing roles of the polysialyltransferases are based on different expression profiles. 9-cis-retinoic acid enhances ST8SIA2 expression, providing a mechanism for understanding how it supports oligodendrocyte differentiation and remyelination. Furthermore, artificial polysialylation of the cell surface promotes oligodendrocyte differentiation. Thus, boosting ST8SIA2 and engineering of polySia are promising strategies for improving myelin repair.

Moschamine inhibits proliferation of glioblastoma cells via cell cycle arrest and apoptosis.

Glioblastoma is the most common and most malignant primary brain tumor with a median survival of 15 months. Moschamine is an indole alkaloid that has a serotoninergic and cyclooxygenase inhibitory effect. In this study, we sought to determine whether moschamine could exert cytotoxic and cytostatic effects on glioma cells in vitro. Moschamine was tested for toxicity in zebrafish. We investigated the effect of moschamine on U251MG and T98G glioblastoma cell lines. Viability and proliferation of the cells were examined with trypan blue exclusion assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the xCELLigence system. Apoptosis (annexin-propidium iodide), cell cycle, and CD24/CD44/CD56/CD15 expression were tested with flow cytometry. Treatment with moschamine significantly reduced cell viability in both cell lines tested. Induction of cell death and cell cycle arrest was confirmed with flow cytometry in both cell lines. After treatment with moschamine, there was a dose-dependent decrease in CD24 and CD44 expression, whereas there was no change in CD56 and CD15 expression in T98G cell line. The zebrafish mortality on the fifth post-fertilization day was zero even for 1 mM of moschamine concentration. The treatment of glioblastoma cell lines with moschamine may represent a novel strategy for targeting glioblastoma.