Roles of Two Major Domains of the Porcine Deltacoronavirus S1 Subunit in Receptor Binding and Neutralization.

Determination of the mechanisms of interspecies transmission is of great significance for the prevention of epidemic diseases caused by emerging coronaviruses (CoVs). Recently, porcine deltacoronavirus (PDCoV) was shown to exhibit broad host cell range mediated by surface expression of aminopeptidase N (APN), and humans have been reported to be at risk of PDCoV infection. In the present study, we first demonstrated overexpression of APN orthologues from various species, including mice and felines, in the APN-deficient swine small intestine epithelial cells permitted PDCoV infection, confirming that APN broadly facilitates PDCoV cellular entry and perhaps subsequent interspecies transmission. PDCoV was able to limitedly infect mice in vivo, distributing mainly in enteric and lymphoid tissues, suggesting that mice may serve as a susceptible reservoir of PDCoV. Furthermore, elements (two glycosylation sites and four aromatic amino acids) on the surface of domain B (S1B) of the PDCoV spike glycoprotein S1 subunit were identified to be critical for cellular surface binding of APN orthologues. However, both domain A (S1A) and domain B (S1B) were able to elicit potent neutralizing antibodies against PDCoV infection. The antibodies against S1A inhibited the hemagglutination activity of PDCoV using erythrocytes from various species, which might account for the neutralizing capacity of S1A antibodies partially through a blockage of sialic acid binding. The study reveals the tremendous potential of PDCoV for interspecies transmission and the role of two major PDCoV S1 domains in receptor binding and neutralization, providing a theoretical basis for development of intervention strategies. IMPORTANCE Coronaviruses exhibit a tendency for recombination and mutation, which enables them to quickly adapt to various novel hosts. Previously, orthologues of aminopeptidase N (APN) from mammalian and avian species were found to be associated with porcine deltacoronavirus (PDCoV) cellular entry in vitro. Here, we provide in vivo evidence that mice are susceptible to PDCoV limited infection. We also show that two major domains (S1A and S1B) of the PDCoV spike glycoprotein involved in APN receptor binding can elicit neutralizing antibodies, identifying two glycosylation sites and four aromatic amino acids on the surface of the S1B domain critical for APN binding and demonstrating that the neutralization activity of S1A antibodies is partially attributed to blockage of sugar binding activity. Our findings further implicate PDCoV's great potential for interspecies transmission, and the data of receptor binding and neutralization may provide a basis for development of future intervention strategies.

Ubenimex Reverses MDR in Gastric Cancer Cells by Activating Caspase-3-Mediated Apoptosis and Suppressing the Expression of Membrane Transport Proteins.

Gastric cancer (GC) is one of the most malignant tumors, accounting for 10% of deaths caused by all cancers. Chemotherapy is often necessary for treatment of GC; the FOLFOX regimen is extensively applied. However, multidrug resistance (MDR) of GC cells prevents wider application of this treatment. Ubenimex, an inhibitor of CD13, is used as an immune adjuvant to treat hematological malignancies. Here, we demonstrate that CD13 expression positively correlates with MDR development in GC cells. Moreover, Ubenimex reverses the MDR of SGC7901/X and MKN45/X cells and enhances their sensitivity to FOLFOX, in part by decreasing CD13 expression, which is accompanied by downregulation of Bcl-xl, Bcl-2, and survivin expression; increased expression of Bax; and activation of the caspase-3-mediated apoptotic cascade. In addition, Ubenimex downregulates expression of membrane transport proteins, such as P-gp and MRP1, by inhibiting phosphorylation in the PI3K/AKT/mTOR pathway to increase intracellular accumulations of 5-fluorouracil and oxaliplatin, a process for which downregulation of CD13 expression is essential. Therefore, the present results reveal a previously uncharacterized function of CD13 in promoting MDR development in GC cells and suggest that Ubenimex is a candidate for reversing the MDR of GC cells.

CD13 expression in B cell malignancies is a hallmark of plasmacytic differentiation.

The diagnosis of Waldenström Macroglobulinaemia (WM)/lymphoplasmacytic lymphoma (LPL) remains one of exclusion because other B-cell lymphoproliferative disorders (B-LPD), such as marginal zone lymphoma (MZL), can fulfil similar criteria, including MYD88 L265P mutation. It has been suggested that expression of the myeloid marker CD13 (also termed ANPEP) is more frequent in LPL than in other B-LPD and has also been described on normal and malignant plasma cells. Here, CD13 expression was tested in a cohort of 1037 B-LPD patients from 3 centres by flow cytometry. The percentage of CD13-expressing cells was found to be variable among B-LPD but significantly higher in WM/LPL (median 31% vs. 0% in non-WM/LPL, P < 0·001). In multivariate linear regression, CD13 expression remained significantly associated with a diagnosis of WM/LPL (P < 0·001). A cut-off value of 2% of CD19+ cells co-expressing CD13 yielded the best diagnostic performance for WM/LPL assertion. This was further improved by association with the presence or absence of IgM paraprotein. Finally, given that previously published transcriptomic data revealed no difference in CD13 (also termed ANPEP) mRNA between normal and pathological B-cells, the hypothesis of some post-transcriptional regulation must be favoured. These results suggest that testing for CD13 expression in routine flow cytometry panels could help to discriminate WM/LPL from other B-LPD.

CD13 as target for tissue factor induced tumor vascular infarction in small cell lung cancer.

OBJECTIVES: Zinc-binding protease aminopeptidase N (CD13) is expressed on tumor vascular cells and tumor cells. It represents a potential candidate for molecular targeted therapy, e.g. employing truncated tissue factor (tTF)-NGR, which can bind CD13 and thereby induce tumor vascular infarction. We performed a comprehensive analysis of CD13 expression in a clinically well characterized cohort of patients with small cell lung cancer (SCLC) to evaluate its potential use for targeted therapies in this disease. MATERIAL AND METHODS: CD13 expression was analyzed immunohistochemically in 27 SCLC patients and correlated with clinical course and outcome. In CD-1 nude mice bearing human HTB119 SCLC xenotransplants, the systemic effects of the CD13-targeting fusion protein tTF-NGR on tumor growth were tested. RESULTS AND CONCLUSION: In 52% of the investigated SCLC tissue samples, CD13 was expressed in tumor stroma cells, while the tumor cells were negative for CD13. No prognostic effect was found in the investigated SCLC study collective with regard to overall survival (p>0.05). In CD-1 nude mice, xenografts of CD13 negative HTB119 SCLC cells showed CD13 expression in the intratumoral vascular and perivascular cells, and the systemic application of CD13-targeted tissue factor tTF-NGR led to a significant reduction of tumor growth. We here present first data on the expression of CD13 in SCLC tumor samples. Our results strongly recommend the further investigation of tTF-NGR and other molecules targeted by NGR-peptides in SCLC patients. Considering the differential expression of CD13 in SCLC samples pre-therapeutic CD13 analysis is proposed for testing as investigational predictive biomarker for patient selection.

CD13 is a marker for onychofibroblasts within nail matrix onychodermis: Comparison of its expression patterns in the nail unit and in the hair follicle.

BACKGROUND: We previously demonstrated the presence of onychodermis, a specialized mesenchymal cell population beneath the nail matrix and proximal nail bed demonstrating CD10 expression. We hypothesize that the onychodermis could be the nail analog of the follicular dermal papilla, which is known to express CD13. We compare CD13 expression patterns between specialized mesenchymes of nail and hair, and compare these findings with CD10 expression patterns. METHODS: CD10 and CD13 immunohistochemistry was performed on polydactyly and adult cadaveric nail units, and on hair follicles in scalp nevus sebaceus excision specimens. RESULTS: CD10 and CD13 were expressed in the mesenchyme below the nail matrix and nail bed. Stronger CD13 expression was observed in the mesenchyme containing onychofibroblasts below the nail matrix compared with that below the nail bed. CD10 was expressed in the dermal sheath of terminal hair follicles, but it was expressed in the dermal sheath and follicular dermal papilla of primitive hair follicles within nevus sebaceus lesions. CD13 was expressed in the dermal sheath and dermal papilla of terminal and primitive hair follicles. CONCLUSION: CD13 may be a marker for onychofibroblasts within nail matrix onychodermis. We demonstrate CD13 expression in the specialized mesenchymes of both nail and hair.

Molecular characterization and dietary regulation of aminopeptidase N (APN) in the grass carp (Ctenopharyngodon idella).

Aminopeptidase N (APN) is a member of the peptidase M1 family and plays an important role in protein digestion. In the present study, an APN gene was cloned from the intestine of Ctenopharyngodon idellus. The full-length cDNA sequence of APN encodes an 892-amino-acid peptide that includes one helix trans-membrane region. Phylogenetic analysis showed that the APN sequence clustered with Danio rerio as its closest neighbor, sharing a sequence similarity of 81.5%. APN mRNA was differentially expressed in different tissues, with a gradient expression from high to low in the tissues of the fore-intestine, hind-intestine, liver, mid-intestine, kidney, muscle, spleen and heart. APN expression in grass carp had a circadian pattern, showing time-dependent higher expression between 06:00 and 18:00 and lower expression between 18:00 and 06:00. In addition, the protein levels and resource in the diet-regulated APN expression suggested that low crude protein (CP) level and fish meal stimulated APN gene expression. Furthermore, the mRNA expression of APN in the intestine was significantly suppressed by high concentrations of glutamine and glutamine dipeptides, respectively. This study may provide valuable knowledge on the regulation of APN expression in teleost, which has potential applications for improving fish dietary formulations.

Heterogeneity of Abnormal RUNX1 Leading to Clinicopathologic Variations in Childhood B-Lymphoblastic Leukemia.

OBJECTIVES: Abnormalities of the RUNX1 gene in childhood B-acute lymphoblastic leukemia (B-ALL) are manifested by ETV6-RUNX1 or RUNX1 amplification. A detailed comparison between the two regarding clinicopathologic features with genetic analysis has not been performed previously. This parallel study assessed how different RUNX1 abnormalities affect the clinicopathology of B-ALL. METHODS: We compared clinicopathologic factors, including age, sex, WBC count, cerebrospinal fluid (CSF) involvement, immunophenotype, and blast proliferation rate between B-ALL with RUNX1 amplification (10 cases) and B-ALL with ETV6-RUNX1 translocation (67 cases) in childhood B-ALL. RESULTS: CD7 was often expressed in RUNX1 amplification but not in ETV6-RUNX1 (44% vs 0%, P = .0001) and appeared to correlate with CSF involvement in the former group (3/4 [75%]). CD13 was often detected in ETV6-RUNX1 with additional RUNX1 gain (38%) with an even higher frequency in double ETV6-RUNX1 translocation (77%), but was not detected in RUNX1 amplification (0%, P < .05). Children with RUNX1 amplification were older and more often CSF positive, while those with ETV6-RUNX1 were younger, more frequently had hyperleukocytosis, and had higher blast proliferation rates. CONCLUSIONS: RUNX1 copy numbers seem to be proportional to the age of B-ALL onset and the frequency of CSF involvement, while RUNX1 amplification vs translocation causes aberrant expression of CD7 and CD13, respectively.

Identification of a unique hepatocellular carcinoma line, Li-7, with CD13(+) cancer stem cells hierarchy and population change upon its differentiation during culture and effects of sorafenib.

BACKGROUNDS: Cancer stem cell (CSC) research has highlighted the necessity of developing drugs targeting CSCs. We investigated a hepatocellular carcinoma (HCC) cell line that not only has CSC hierarchy but also shows phenotypic changes (population changes) upon differentiation of CSC during culture and can be used for screening drugs targeting CSC. METHODS: Based on a hypothesis that the CSC proportion should decrease upon its differentiation into progenitors (population change), we tested HCC cell lines (HuH-7, Li-7, PLC/PRF/5, HLF, HLE) before and after 2 months culture for several markers (CD13, EpCAM, CD133, CD44, CD90, CD24, CD166). Tumorigenicity was tested using nude mice. To evaluate the CSC hierarchy, we investigated reconstructivity, proliferation, ALDH activity, spheroid formation, chemosensitivity and microarray analysis of the cell populations sorted by FACS. RESULTS: Only Li-7 cells showed a population change during culture: the proportion of CD13 positive cells decreased, while that of CD166 positive cells increased. The high tumorigenicity of the Li-7 was lost after the population change. CD13(+)/CD166(-) cells showed slow growth and reconstructed the bulk Li-7 populations composed of CD13(+)/CD166(-), CD13(-)/CD166(-) and CD13(-)/CD166(+) fractions, whereas CD13(-)/CD166(+) cells showed rapid growth but could not reproduce any other population. CD13(+)/CD166(-) cells showed high ALDH activity, spheroid forming ability and resistance to 5-fluorouracil. Microarray analysis demonstrated higher expression of stemness-related genes in CD166(-) than CD166(+) fraction. These results indicated a hierarchy in Li-7 cells, in which CD13(+)/CD166(-) and CD13(-)/CD166(+) cells serve as slow growing CSCs and rapid growing progenitors, respectively. Sorafenib selectively targeted the CD166(-) fraction, including CD13(+) CSCs, which exhibited higher mRNA expression for FGF3 and FGF4, candidate biomarkers for sorafenib. 5-fluorouracil followed by sorafenib inhibited the growth of bulk Li-7 cells more effectively than the reverse sequence or either alone. CONCLUSIONS: We identified a unique HCC line, Li-7, which not only shows heterogeneity for a CD13(+) CSC hierarchy, but also undergoes a "population change" upon CSC differentiation. Sorafenib targeted the CSC in vitro, supporting the use of this model for screening drugs targeting the CSC. This type of "heterogeneous, unstable" cell line may prove more useful in the CSC era than conventional "homogeneous, stable" cell lines.

Prognostic significance of aminopeptidase-N (CD13) in hepatoblastoma.

BACKGROUND: Hepatoblastoma is a rare childhood malignant tumor that originates from immature hepatic cells. Aminopeptidase-N(CD13), an ectopeptidase that promotes tumor invasion and metastasis, is expressed in fetal stage hepatic progenitor cells, although its role in hepatoblastoma remains unclear. METHODS: The expression pattern of CD13 was investigated on immunohistochemistry in 30 tissue samples from 27 hepatoblastoma patients (16 with predominantly embryonal [pE] histology and 14 with predominantly fetal [pF] histology). Immunoreactive score (IRS) was used to quantify staining data, and the relationship between CD13 expression, clinicopathological factors, and clinical outcome was investigated. The biological function of CD13 was also examined in the hepatoblastoma cell lines Huh6 and HepG2. RESULTS: All specimens stained positive for CD13, with higher CD13 expression in pE than in pF hepatoblastoma samples (median IRS, 4; range, 2-9 vs 2; range, 1-4). Strong CD13 expression was correlated with vascular invasion. Five year event-free survival and overall survival were better in patients with CD13(low) than in those with CD13(high) tumors (100% vs 51.0%, P = 0.026; and 100% vs 74.0%, P = 0.114, respectively). A CD13-neutralizing antibody and the potent CD13 inhibitor, Ubenimex, suppressed invasive activity in HepG2 cells in vitro. CONCLUSIONS: CD13 expression is associated with hepatoblastoma invasiveness and could be a novel prognostic marker for hepatoblastoma.

Influence of aberrant myeloid expression on acute lymphoblastic leukemia in children and adolescents from Maranhão, Brazil.

The aim of this study was to evaluate myeloid expression in acute lymphoblastic leukemia (ALL) in children and adolescents who had been referred to the Oncology Department in a hospital in the State of Maranhão based on demographic, laboratory, and clinical data. Myeloid expression was evaluated in 65 patients under 18 years of age who were diagnosed with morphological, cytochemical, and immunophenotypes of ALL. Demographic, laboratory (hemogram), and clinical variables were obtained from medical records. The sample was divided into groups with and without anomalous myeloid expression to analyze the variables. Myeloid expression was observed in 49.2% of the sample. Platelet count was significantly lower in the group of children without aberrant myeloid expression (33,627 platelets/mm(3), P = 0.01). A total of 88.9% of children with B-cell ALL without myeloid expression showed less than 50,000 platelets/mm(3) (P = 0.01). Thus, platelet count may be an important parameter in the diagnosis of children with ALL without myeloid aberrant expression and may indicate a greater risk of bleeding during treatment in this group.

Possible contribution of aminopeptidase N (APN/CD13) to migration and invasion of human osteosarcoma cell lines.

Osteosarcoma is the most common primary malignancy of the bone. Aminopeptidase N (APN/CD13), a Zn+2-dependent ectopeptidase localized on the cell surface, is widely considered to influence the invasion mechanism. This study explores the potential involvement of APN in migration and invasion of human osteosarcoma cells in vitro using inhi-bitors and activators of APN. Cells treated with APN inhibitor bestatin displayed decreased migration and invasion in a Boyden chamber Transwell assay. Western blotting revealed reduced levels of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathway proteins, reduced phosphorylation of p38, ERK1/2 and JNK and decreased levels of NF-κB. Bestatin treatment also lowered APN, matrix metalloproteinase (MMP)-2 and -9 enzymatic activity and their mRNA expression. Reduced MMP-2 and -9 protein levels were also observed. By comparison, cells treated with cytokine interleukin-6 (IL-6), a stimulator of APN, displayed increased migration and invasion. Western blotting revealed increased levels of MAPK and PI3K pathway proteins, phosphorylated p38, ERK1/2 and JNK, and NF-κB. IL-6 treatment also increased APN and MMP-2 and -9 enzymatic activity. An increase of APN, MMP-2 and -9 mRNA levels, and MMP-2 and -9 protein levels was also observed. Together these experiments reveal potential enzymatic and signalling roles for APN in osteosarcoma and establish a starting point for an in-depth analysis of the role of APN in regulating invasiveness. A deeper knowledge about the regulatory mechanisms of APN may contribute to the development of anti-metastatic therapies.

RNA interference-mediated knockdown of three putative aminopeptidases N affects susceptibility of Spodoptera exigua larvae to Bacillus thuringiensis Cry1Ca.

Aminopeptidase N (APN) isoforms in insects have been documented to be involved in the mode of action of insecticidal crystal proteins (Cry) from Bacillus thuringiensis. Here we cloned two novel Seapns from the larval midgut of Spodoptera exigua, a major pest of many crops of economic importance in China. According to a phylogenetic analysis, these two novel SeAPNs, along with the four SeAPN isoforms already described, belong to six different clades. All the six SeAPNs share similar structural features. From N- to C-terminus a signal peptide, a gluzincin aminopeptidase motif, a zinc binding/gluzincin motif, and a glycosylphosphatidylinositol-anchor sequence are located. The six Seapn genes were highly expressed at the larval stage, especially in the larval gut. Ingestion during four consecutive days of double-stranded RNAs (dsRNAs) targeting Seapn1, Seapn2, Seapn3, Seapn4, Seapn5 and Seapn6 significantly reduced corresponding mRNA levels by 55.6%, 45.5%, 43.2%, 56.8%, 45.4%, and 46.0% respectively, compared with those recorded in control larvae fed on non-specific dsRNA (dsegfp). When the larvae that previously ingested phosphate buffered saline (PBS)-, dsegfp-, or six dsSeapns-overlaid diets were then exposed to a diet containing Cry1Ca, the larval mortalities were 71.2%, 69.3%, 52.0%, 77.2%, 43.3%, 62.0%, 65.4% and 53.8% respectively recorded after 6days. ANOVA analysis revealed that the larvae previously fed on dsSeapn1-, dsSeapn3-, and dsSeapn6-overlaid diets had significantly lower mortalities than those previously ingested PBS-, dsegfp-, dsSeapn2-, dsSeapn4- and dsSeapn5-overlaid diets. Thus, these results suggest that SeAPN1, SeAPN3 and SeAPN6 may be candidate receptors for Cry1Ca in S. exigua.

Rat cortex and hippocampus-derived soluble factors for the induction of adipose-derived mesenchymal stem cells into neuron-like cells.

To simulate brain microenvironment, adipose-derived mesenchymal stem cells (AMSC) were induced to differentiate to neuronal-like cells in rat cortex and hippocampus medium (Cox + Hip). First, isolated AMSC were characterized by flow cytometer and the capacity of adipogenesis and osteogenesis. After induction in rat cortex and hippocampus conditioned medium, the cell morphological change was examined and neural marker proteins (ß-Ш-Tubulin, NSE, Nissl body) expression was detected by immunofluorescence staining. A variety of synaptic marker proteins, including GAP43, SHANK2, SHANK3 and Bassoon body, were detected. ELISA was used to measure brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) secretion at different time-points. AMSCs positively expressed CD13, CD44 and CD90 and could differentiate into osteoblasts or adipocytes. After induction in Cox + Hip medium for 14 days, cells had a typical neuronal perikaryal appearance, which was suggestive of neuronal differentiation. After 14 days of Cox + Hip treatment, the percentage of cells expressing ß-Ⅲ-Tubulin, NSE and Nissl was 53.9 ± 0.8%, 51.3 ± 1.7% and 16.4 ± 2.1%, respectively. Expression of GAP43, SHANK2, SHANK3 and Bassoon body was detected, indicating synapse formation after treatment in Cox + Hip medium. Differentiated AMSCs secreted neurotrophic factors NGF and BDNF. Thus rat cortex and hippocampus-derived soluble factors can induce AMSCs to a neuronal-like phenotype, suggesting that AMSCs have a dual role in supplementing newborn neurons and secreting neurotrophic factors, and therefore could be help as a potential treatment for nervous system diseases.

Unlinked genetic loci control the reduced transcription of aminopeptidase N 1 and 3 in the European corn borer and determine tolerance to Bacillus thuringiensis Cry1Ab toxin.

Transgenic expression of Bacillus thuringiensis (Bt) crystalline (Cry) toxins by crop plants result in reduced insect feeding damage, but sustainability is threatened by the development of resistance traits in target insect populations. We investigated Bt toxin resistance trait in a laboratory colony of the European corn borer, Ostrinia nubilalis, selected for increased survival when exposed to Cry1Ab and correlated survival on Cry1Ab toxin with a constitutive ∼146.2 ± 17.3-fold reduction in midgut aminopeptidase N1 (apn1) transcript levels. A 7.1 ± 1.9-fold reduction apn3 transcript level was also correlated with Cry1Ab resistance. Quantitative trait locus (QTL) mapping identified a single major genome region controlling Cry1Ab resistance on linkage group 24 (LG24), and a minor QTL on LG27. Both QTL were independent of apn1 and apn3 loci on LG02. Positional mapping identified genetic markers that may assist in the identification of causal gene(s) within QTL intervals. This study indicates that genetic factor(s) may act in trans to reduce both apn1 and apn3 expression in Cry1Ab resistant O. nubilalis larvae, and suggest that gene regulatory pathways can influence Bt resistance traits. These findings show that gene interactions (epistasis) may influence Bt resistance in target insect populations.

Evaluation of 99mTc-probestin for imaging APN expressing tumors by SPECT.

Aminopeptidase N (APN) is known to play important roles in tumor angiogenesis, tumor cell invasion, and metastasis. Thus, APN is an attractive biomarker for imaging tumor angiogenesis. Here we report results obtained from biodistribution and single photon emission computed tomography (SPECT) imaging studies of a technetium-99m labeled probestin (a potent APN inhibitor) conjugate containing a tripeptide, Asp-DAP-Cys (DAP=2,3-diaminopropionic acid), chelator and a 8-amino-3,6-dioxaoctanoic acid (PEG2) linker conducted in nude mice xenografted with HT-1080 human fibrosarcoma tumors (APN-positive tumors). These results collectively demonstrate that (99m)Tc-probestin uptake by tumors and other APN expressing tissues in vivo is specific and validate the use of probestin as a vector for targeting APN in vivo.

Clinical importance of myeloid antigen expression in Moroccan patients with adult B-lineage acute lymphoblastic leukemia.

The prognostic significance of myeloid antigen (MyAg) expression in acute lymphoblastic leukemias (ALL), especially in adult patients, is still controversial. In the present report, frequency and clinical significance of MyAg (CD13 and/or CD33) in blast cells were assessed in 80 consecutive adult (≥18 years) patients with B-lineage acute lymphoblastic leukemia (B-ALL), representing 66.7% of 120 patients diagnosed as having ALL during the study period. Immunophenotyping was used to classify leukemic cells as Bor Tlymphoblasts and to identify the aberrant expression of myeloid-associated antigens. MyAg expression was documented in 52.5% of the 80 B-ALL cases analyzed. CD13 was the most commonly antigen expressed (36.3%) followed by CD33 (28.8%). No significant associations were found between the expression of MyAg and the presence of known adverse prognostic features (eg: age>30 years, male gender, high WBC count and Philadelphia positivity). Also, we failed to observe any statistically significant difference between MyAg-positive and MyAg-negative patients in terms of achievement of complete remission and overall survival at 3 years. This study demonstrates that the presence of MyAg on lymphoblastic cells lacks prognostic value In Moroccan patients with adult B-ALL.

Transcriptomic study of dormant gastrointestinal cancer stem cells.

We previously discovered the coexistence of dormant and proliferating cancer stem cells (CSCs) in gastrointestinal cancer, which leads to chemoradiation resistance. CD13-/CD90+ proliferating liver CSCs are sensitive to chemotherapy, and CD13+/CD90- dormant CSCs have a limited proliferation ability, survive in hypoxic areas with reduced oxidative stress, and relapse and metastasize to other organs. In such CD13+ dormant cells, non-homologous end-joining, an error-prone repair mechanism, is dominant after DNA damage, whereas high-fidelity homologous recombination is apparent in CD13- proliferating cells, suggesting the significance of dormancy as an essential protective mechanism of therapy resistance. However, this mechanism may also play a role in the generation and accumulation of heterogeneity during cancer progression, although the exact mechanism remains to be understood. Through transcriptomic study, we elucidated the underlying epigenetic mechanism for malignant behavior of dormant CSCs, i.e., simultaneous activation of several pathways including EZH2- and TP53-related proteins in response to microRNA101, suggesting that a pharmacogenomic approach would open an era to novel molecular targeting cancer therapy.

CD13 regulates dendritic cell cross-presentation and T cell responses by inhibiting receptor-mediated antigen uptake.

Dendritic cell (DC) Ag cross-presentation is generally associated with immune responses to tumors and viral Ags, and enhancement of this process is a focus of tumor vaccine design. In this study, we found that the myeloid cell surface peptidase CD13 is highly and specifically expressed on the subset of DCs responsible for cross-presentation, the CD8(+) murine splenic DCs. In vivo studies indicated that lack of CD13 significantly enhanced T cell responses to soluble OVA Ag, although development, maturation, and Ag processing and presentation of DCs are normal in CD13KO mice. In vitro studies showed that CD13 regulates receptor-mediated, dynamin-dependent endocytosis of Ags such as OVA and transferrin but not fluid-phase or phagocytic Ag uptake. CD13 and Ag are cointernalized in DCs, but CD13 did not coimmunoprecipitate with Ag receptors, suggesting that CD13 does not control internalization of specific receptors but regulates endocytosis at a more universal level. Mechanistically, we found that phosphorylation of the endocytic regulators p38MAPK and Akt was dysregulated in CD13KO DCs, and blocking of these kinases perturbed CD13-dependent endocytic uptake. Therefore, CD13 is a novel endocytic regulator that may be exploited to enhance Ag uptake and T cell activation to improve the efficacy of tumor-targeted vaccines.

Determining the involvement of two aminopeptidase Ns in the resistance of Plutella xylostella to the Bt toxin Cry1Ac: cloning and study of in vitro function.

The cloning, expression in vitro, and characterization of two aminopeptidase Ns (APN5s and APN2s) isolated from the midgut of Cry1Ac-resistant (R) and susceptible (S) strains of Plutella xylostella larvae are presented in this paper. The deduced amino acid sequences of APN5s included C-terminal GPI-modification sites, the gluzincin aminopeptidase motif GATEN, and three N-glycosylated sites; those of APN2s had no GPI-modification sites, had gluzincin aminopeptidase motif GAMEN, and had four N-glycosylated sites. O-glycosylated sites were not predicted for either APN. Because APN2R and APN2S cDNAs contained the same nucleotides, only full-length cDNAs encoding APN5R and APN5S were expressed in Trichoplusia ni cells. Far-Western blotting showed that the expressed receptor APN5 bound to the Cry1Ac toxin. An enzyme-specific activity experiment also showed that APN5 genes were expressed in T. ni cells. ELISA revealed no differences in the binding of expression proteins from the resistant and susceptible strain with Cry1Ac.

Comparing the biological characteristics of adipose tissue-derived stem cells of different persons.

Scientists have found that cell sex is a variable that considerably influences the regeneration abilities of muscle-derived stem cells' in mice. We try to find out whether the cell sex or cell age (the age of donor) will influence the biological characteristics of human adipose tissue-derived stem cells (H-ADSCs). The results indicate that cell sex influences the proliferation, differentiation, paracrine, and anti-apoptosis abilities of the H-ADSCs, and cell age may also affect the H-ADSCs' differentiation and anti-apoptosis abilities.