Anti-cancer effects of nitazoxanide in epithelial ovarian cancer in-vitro and in-vivo.

Epithelial ovarian cancer is one of the most lethal gynecologic malignancies and poses a considerable threat to women's health. Although the progression-free survival of patients has been prolonged with the application of anti-angiogenesis drugs and Poly (ADP-ribose) polymerases (PARP) inhibitors, overall survival has not substantially improved. Thus, new therapeutic strategies are essential for the treatment of ovarian cancer. Nitazoxanide (NTZ), an FDA-approved anti-parasitic drug, has garnered attention for its potential anti-cancer activity. However, the anti-tumor effects and possible underlying mechanisms of NTZ on ovarian cancer remain unclear. In this study, we investigated the anti-tumor effects and the mechanism of NTZ on ovarian cancer in vitro and in vivo. We found that NTZ inhibited the proliferation of A2780 and SKOV3 epithelial ovarian cancer cells in a time- and concentration-dependent manner; Furthermore, NTZ suppressed the metastasis and invasion of A2780 and SKOV3 cells in vitro, correlating with the inhibition of epithelial-mesenchymal transition; Additionally, NTZ suppressed the Hippo/YAP/TAZ signaling pathway both in vitro and in vivo and demonstrated a good binding activity with core genes of Hippo pathway, including Hippo, YAP, TAZ, LATS1, and LATS2. Oral administration of NTZ inhibited tumor growth in xenograft ovarian cancer mice models without causing considerable damage to major organs. Overall, these data suggest that NTZ has therapeutic potential for treating epithelial ovarian cancer.

MiR-454-3p promotes apoptosis and autophagy of AML cells by targeting ZEB2 and regulating AKT/mTOR pathway.

BACKGROUND: miR-454-3p is considered to have a crucial role in cancer progression, but the potential involvement in acute myeloid leukemia (AML) remains unclear. METHODS: Expression of miR-454-3p and ZEB2 mRNA and protein were quantified in AML cell lines. Cells were transfected with miR-454-3p inhibitor or mimic and cell growth was assessed by colony formation and CCK-8 assays and the cell cycle, apoptosis and autophagy were investigated by Western blotting, flow cytometry, immunofluorescence and 3-methyladenine (3-MA) treatment. RESULTS: miR-454-3p expression was attenuated in AML cells. miR-454-3p overexpression attenuated cell growth and stimulated cell cycle arrest, apoptosis and autophagy. Dual-luciferase reporter assays and bioinformatics analysis showed that AML progression was inhibited when miR-454-3p regulated ZEB2, an effect confirmed by rescue assays. 3-MA reduced the autophagy-inducing effect of ZEB2 knockdown and indicated that autophagy induced apoptosis. miR-454-3p downregulated p-mTOR/p-AKT levels in AML cells. CONCLUSION: The novel role of miR-454-3p as a tumor inhibitor in AML via regulation of the ZEB2/AKT/mTOR axis was demonstrated, indicating miR-454-3p as a potential new molecular target for AML.

Downregulation of Polo-like kinase 4 induces cell apoptosis and G2/M arrest in acute myeloid leukemia.

BACKGROUND: Polo-like kinase 4 (PLK4) is a crucial regulator for centriole replication and is reported to be aberrantly expressed in various cancers, where it participates to tumorigenesis. However, PLK4 effect in acute myeloid leukemia (AML), is still uncertain. This study investigates the function of PLK4 in AML. METHODS: Quantitative real-time PCR was used to measure the level of PLK4. Centrinone, a selective PLK4 small molecule inhibitor, was used for PLK4 inhibition and explore its effect in AML cells. The cell growth was detected by the CCK8, while the cell cycle and apoptosis were assessed by flow cytometry. The level of proteins associated with apoptosis, cell cycle and endoplasmic reticulum (ER) stress were analyzed by western blotting. RESULTS: PLK4 was overexpressed in AML cells. PLK4 knockdown or its specific inhibition by centrinone induced G2/M phase arrest via suppressing the expression of cyclin B1 and Cdc2 and promoting the level of proapoptotic proteins. Moreover, PLK4 targeting enhanced the level of proteins related to ER stress, such as GRP78, ATF4, ATF6, and CHOP. CONCLUSION: These findings demonstrated that targeting PLK4 can induce apoptosis, G2/M and ER stress in AML cells.

DNMT3A R882H mutation promotes acute leukemic cell survival by regulating glycolysis through the NRF2/NQO1 axis.

BACKGROUND: Studies have confirmed that acute myeloid leukemia (AML) cells with DNA methyltransferase 3A Arg882His (DNMT3A R882H) mutation show an increased proliferation capability. However, the associated mechanism is still unclear. Glycolysis is involved in regulating malignant proliferation of cancer cell. Hence, we analyzed whether the DNMT3A R882H mutation interferes with glycolysis and thereby influences AML cell proliferation. METHODS: We generated AML cell line carrying a DNMT3A-R882H mutation and compared it with the wild type (DNMT3A-WT) with regard to glycolysis regulation. Moreover, we analyzed the cell line's proliferation and apoptosis by a CCK-8 assay, western blotting, and flow cytometry. The role of NRF2/NQO1 signaling in regulating glycolysis was investigated by NRF2-knockdown and Brusatol (specific inhibitor of NRF2) treatment. RESULTS: DNMT3A R882H cells had a higher glucose transport capacity compared to WT cells and their viability could be reduced by glucose deprivation. Moreover, daunorubicin had a slight inhibitory effect on glycolysis while glycolysis inhibition re-sensitized mutant cells to daunorubicin. Obviously, DNMT3A R882H mutation activated the NRF2/NQO1 pathway and enhanced the glycolytic activity in mutant cells. CONCLUSION: Taken together, these results suggest a novel mechanism by which a DNMT3A R882H mutation promotes glycolysis via activation of NRF2/NQO1 pathway. A parallel glycolysis inhibition adds to the anticancer effects of daunorubicin which might lead to a novel therapeutic approach for the treatment of AML patients carrying a DNMT3A R882H mutation.

Exploration of the cysteine reactivity of human inducible Hsp70 and cognate Hsc70.

Hsp70s are multifunctional proteins and serve as the central hub of the protein quality control network. Hsp70s are also related to a number of diseases and have been established as drug targets. Human HspA1A (hHsp70) and HspA8 (hHsc70) are the major cytosolic Hsp70s, and they have both overlapping and distinct functions. hHsp70 contains five cysteine residues, and hHsc70 contains four cysteine residues. Previous studies have shown these cysteine residues can undergo different cysteine modifications such as oxidation or reaction with electrophiles to regulate their function, and hHsp70 and hHsc70 have different cysteine reactivity. To address the mechanism of the differences in cysteine reactivity between hHsp70 and hHsc70, we studied the factors that determine this reactivity by Ellman assay for the quantification of accessible free thiols and NMR analysis for the assessment of structural dynamics. We found the lower cysteine reactivity of hHsc70 is probably due to its lower structural dynamics and the stronger inhibition effect of interaction between the α-helical lid subdomain of the substrate-binding domain (SBDα) and the ß-sheet substrate-binding subdomain (SBDß) on cysteine reactivity of hHsc70. We determined that Gly557 in hHsp70 contributes significantly to the higher structural dynamics and cysteine reactivity of hHsp70 SBDα. Exploring the cysteine reactivity of hHsp70 and hHsc70 facilitates an understanding of the effects of redox reactions and electrophiles on their chaperone activity and regulation mechanisms, and how these differences allow them to undertake distinct cellular roles.

Production, characterization and antioxidant activity of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1.

At present, the study on exopolysaccharid is mainly focused on lactic acid bacteria, and the research on exopolysaccharide produced by yeast, especially Sporidiobolus pararoseus, is relatively few. Therefore, the aim of this study was to explore the characterization and antioxidant activities of a novel neutral exopolysaccharide SPZ, which was isolated and purified from S. pararoseus PFY-Z1. The results showed that SPZ was mainly composed of mannose, followed by glucose, with a molecular weight was 24.98 kDa, had O-glycosidic bonds, no crystalline, and no triple helix structure. Based on fourier transform-infrared, high-performance liquid chromatography and nuclear magnetic resonance analyses, SPZ was identified to be a exopolysaccharide with some side chains, presence of α-, ß-pyranose ring and nine sugar residues. Furthermore, the morphology features of SPZ have performed a relatively rough and uneven surface, covered with small pores and fissures. Moreover, SPZ had higher antioxidant activities and the maximum scavenging abilities of ⋅OH, NO2- and reducing power were 28.05 ± 0.73%, 92.76 ± 1.86% and 0.345 ± 0.024, respectively. Hence, SPZ could be used as a potential antioxidant application in the food and pharmaceutical industries.

DNMT3A R882H mutation drives daunorubicin resistance in acute myeloid leukemia via regulating NRF2/NQO1 pathway.

BACKGROUND: DNA methyltransferase 3A (DNMT3A) often mutate on arginine 882 (DNMT3AR882) in acute myeloid leukemia (AML). AML patients with DNMT3A R882 mutation are usually resistant to daunorubicin treatment; however, the associated mechanism is still unclear. Therefore, it is urgent to investigate daunorubicin resistance in AML patients with DNMT3A R882 mutant. METHOD: AML cell lines with DNMT3A-wild type (DNMT3A-WT), and DNMT3A-Arg882His (DNMT3A-R882H) mutation were constructed to investigate the role of DNMT3A R882H mutation on cell proliferation, apoptosis and cells' sensitivity to Danunorubin. Bioinformatics was used to analyze the role of nuclear factor-E2-related factor (NRF2) in AML patients with DNMT3A R882 mutation. The regulatory mechanism of DNMT3A R882H mutation on NRF2 was studied by Bisulfite Sequencing and CO-IP. NRF2 inhibitor Brusatol (Bru) was used to explore the role of NRF2 in  AML cells carried DNMT3A R882H mutation. RESULTS: AML cells with a DNMT3A R882H mutation showed high proliferative and anti-apoptotic activities. In addition, mutant cells were less sensitive to daunorubicin and had a higher NRF2 expression compared with those in WT cells. Furthermore, the NRF2/NQO1 pathway was activated in mutant cells in response to daunorubicin treatment. DNMT3A R882H mutation regulated the expression of NRF2 via influencing protein stability rather than decreasing methylation of NRF2 promoter. Also, NRF2/NQO1 pathway inhibition improved mutant cells' sensitivity to daunorubicin significantly. CONCLUSION: Our findings identified NRF2 as an important player in the regulation of cell apoptosis through which helps mediate chemoresistance to daunorubicin in AML cells with DNMT3A R882H mutation. Targeting NRF2 might be a novel therapeutic approach to treat AML patients with a DNMT3A R882H mutation. Video abstract.

miRNA-222-3p enhances the proliferation and suppresses the apoptosis of acute myeloid leukemia cells by targeting Axin2 and modulating the Wnt/ß-catenin pathway.

MicroRNA (miRNA)-222-3p is overexpressed in numerous tumors, where it acts as an oncogene. Although miRNA-222 is highly expressed in acute myeloid leukemia (AML), its functions and the mechanisms underlying these functions have not yet been fully elucidated. This study aimed to investigate the regulatory roles of miRNA-222-3p in AML and the molecular mechanisms underlying these roles. In this study, we observed that miRNA-222-3p increased the viability and suppressed the apoptosis of AML cells. Axin2 was demonstrated to be a direct target of miRNA-222-3p, which when overexpressed, inhibited Axin2 expression and stimulated the Wnt/ß-catenin pathway. In contrast, upregulation of Axin2 expression levels reduced the viability and enhanced the apoptosis of AML cells. Moreover, it partially reversed the effects of the miRNA-222-3p mimic on the proliferation and apoptosis of, and modulation of the Wnt/ß-catenin pathway in, AML cells. Taken together, this study provides strong evidence that miRNA-222-3p can serve as a molecular target for AML treatment.

RIP1-dependent Apoptosis and Differentiation Regulated by Skp2 and Akt/GSK3ß in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a heterogeneous neoplasm characterized by variations in cytogenetics and molecular abnormalities, which result in variable response to therapy. Receptor-interacting serine/threonine kinase 1 (RIP1)-mediated necroptosis has been reported to have a potential role in the treatment of AML. We obtained Skp2 and RIP1 are significantly overexpressed in AML samples using original published data, and identified that Skp2-depletion in AML cells significantly suppressed RIP1. Functional analysis showed that the inhibition of RIP1 caused by necrostatin-1 (Nec-1) inhibited the proliferation, simultaneously facilitate both the apoptosis and differentiation of AML cells. Mechanistical analysis elucidated that knockdown of Skp2 suppresses RIP1 by transcriptional regulation but not by proteasome degradation. Additionally, Skp2 regulated the function of RIP1 by decreasing K63-linked ubiquitin interaction with RIP1. Moreover, the suppression of Akt/GSK3ß was observed in Skp2 knockdown stable NB4 cells. Also, GSK3ß inactivation via small-molecule inhibitor treatment remarkably decreased RIP1 level. RIP1 regulates differentiation by interacting with RARα, increasing RA signaling targets gene C/EBPα and C/EBPß. In conclusion, our study provides a novel insight into the mechanism of tumorigenesis and the development of AML, for which the Skp2-Akt/GSK3ß-RIP1 pathway can be developed as a promising therapeutic target.

MiRNA-301b-3p induces proliferation and inhibits apoptosis in AML cells by targeting FOXF2 and regulating Wnt/ß-catenin axis.

BACKGROUND: MiRNA-301b-3p functions as an oncomiRNA or tumor suppressor, and has been reported in various cancer types, including pancreatic, colorectal, oral, hepatocellular and lung cancers. Although the expression of miRNA-301b-3p is upregulated in acute myeloid leukemia (AML), its biological function and precise mechanisms remain unclarified. This study explores the roles of miRNA-301b-3p in AML, with the aim of ascertaining its regulatory action on Wnt/ß-catenin axis by targeting Forkhead box F2 (FOXF2). METHODS: The expression levels of miRNA-301b-3p and FOXF2 were measured by quantitative real-time PCR. The effects of miRNA-301b-3p knockdown and overexpression on cell proliferation were evaluated by CCK8 and cell counting assays, while cell apoptosis was analyzed by flow cytometry. The expression levels of apoptosis-related proteins, including FOXF2, and other targets in Wnt/ß-catenin axis were determined by immunoblotting. Possible interaction between miRNA-301-3p and FOXF2 in AML cells was examined by luciferase reporter assays. RESULTS: MiRNA-301b-3p was dramatically upregulated in AML cells, and showed a negative correlation with FOXF2 expression. Downregulation of miRNA-301b-3p suppressed proliferation and promoted apoptosis in AML cells. MiRNA-301b targeted FOXF2 to regulate Wnt/ß-catenin axis. In the rescue experiments, FOXF2 overexpression partly reversed the effect of miRNA-301b-3p mimic in AML cells. CONCLUSION: The current findings demonstrate that miRNA-301b-3p targets FOXF2 to induce proliferation and inhibit apoptosis in AML cells via regulation of Wnt/ß-catenin axis.

ZFP91 promotes cell proliferation and inhibits cell apoptosis in AML via inhibiting the proteasome-dependent degradation of RIP1.

Acute myeloid leukemia (AML) is a quickly progressive and devastated hematological malignancy with large rate of relapse and the appearance of chemotherapy resistance. Therefore, the identification of new therapeutic targets is urgent. ZFP91 is a hidden oncogene. Nevertheless, how ZFP91 takes part in regulating AML is less clear. Our research aims at investigating the molecular mechanisms and uncovering the effects of ZFP91 on AML. This research demonstrates that ZFP91 boosts AML cell proliferation and stops AML cell apoptosis. Mechanistically, experimental results showed the interaction between ZFP91 and RIP1 and inhibitory effect of ZFP91 on the K48-linked ubiquitination of endogenous RIP1, which is an important molecule in AML. Taken together, our results provide the evidence that targeted inhibition of ZFP91 could be a hopeful measure to treat AML.

PES derivative PESA is a potent tool to globally profile cellular targets of PES.

PES (2-phenylethynesulfonamide, pifithrin-µ, PFTµ) is an electrophilic compound that exhibits anticancer properties, protects against chemotherapy-induced peripheral neuropathy in chemotherapy, and shows immunomodulatory, anti-inflammatory and anti-viral activities. PES generally shows higher cytotoxicity towards tumor cells than non-tumor cells. The mechanism of action of PES is unclear but may involve the covalent modification of proteins as PES has been found to be a covalent inhibitor of Hsp70. We developed a new PES derivative PESA with a terminal alkynyl group to perform click-reaction-assisted activity-based protein profiling (click-reaction ABPP) and used this to screen for cellular targets of PES. We found PES and its derivatives PES-Cl and PESA have comparable ability to undergo a Michael addition reaction with GSH and Hsp70, and showed similar cytotoxicity. By fluorescence imaging and proteomics studies we identified over 300 PESA-attached proteins in DOHH2 cells. Some proteins involved in cancer-related redox processes, such as peroxiredoxin 1 (PRDX1), showed higher frequency and abundance in mass spectrometry detection. Our results suggest that cytotoxicity of PES and its derivatives may be related to attack of protein thiols and cellular GSH resulting in breakdown of cellular redox homeostasis. This study provides a powerful new tool compound within the PES class of bioactive compounds and gives insight into the working mechanisms of PES and its derivatives.

Simultaneous reduction in cadmium and arsenic accumulation in rice (Oryza sativa L.) by iron/iron-manganese modified sepiolite.

It is challenging to reduce the cadmium (Cd) and arsenic (As) contents of brown rice simultaneously due to their converse chemical behaviors in the paddy soil. Clay minerals, such as sepiolite (SEP), have significant advantages in remediating Cd-contaminated soil. Moreover, iron or manganese oxide loaded SEP can improve the As adsorption efficiency. Herein, ferric nitrate modified sepiolite (NIMS) and iron­manganese modified sepiolite (FMS) were prepared to study their effects on Cd and As accumulation in rice using pot experiments. The results showed that NIMS and FMS had a larger specific surface area than SEP. The application of SEP only decreased Cd content (by 45%), while NIMS and FMS treatments reduced both Cd (by 57% and 87%) and As (by 30% and 25%) contents in brown rice compared with the control. The X-ray photoelectron spectroscopy (XPS) analysis results indicated that MnO2 and MnOOH⁎ in FMS enhanced the adsorption and co-precipitation of Cd as well as the oxidation of As(III) to As(V). The NIMS, as well as the FMS application, increased soil pH, decreased the exchangeable Cd and non-specifically and specifically adsorbed As fractions in soil, and reduced the level of Cd in the pore water. Moreover, NIMS and FMS addition limited the transfer of As from the soil to the roots by enhancing its sequestration in the iron plaque. On the other hand, FMS treatment significantly promoted the uptake of Mn by rice (P < 0.05). The results suggested that both NIMS and FMS were promising materials for simultaneous reduction of Cd and As accumulation in rice. Notably, FMS had better performance in reducing the Cd content in rice than that of NIMS.

S-Glutathionylation of human inducible Hsp70 reveals a regulatory mechanism involving the C-terminal α-helical lid.

Heat shock protein 70 (Hsp70) proteins are a family of ancient and conserved chaperones. Cysteine modifications have been widely detected among different Hsp70 family members in vivo, but their effects on Hsp70 structure and function are unclear. Here, we treated HeLa cells with diamide, which typically induces disulfide bond formation except in the presence of excess GSH, when glutathionylated cysteines predominate. We show that in these cells, HspA1A (hHsp70) undergoes reversible cysteine modifications, including glutathionylation, potentially at all five cysteine residues. In vitro experiments revealed that modification of cysteines in the nucleotide-binding domain of hHsp70 is prevented by nucleotide binding but that Cys-574 and Cys-603, located in the C-terminal α-helical lid of the substrate-binding domain, can undergo glutathionylation in both the presence and absence of nucleotide. We found that glutathionylation of these cysteine residues results in unfolding of the α-helical lid structure. The unfolded region mimics substrate by binding to and blocking the substrate-binding site, thereby promoting intrinsic ATPase activity and competing with binding of external substrates, including heat shock transcription factor 1 (Hsf1). Thus, post-translational modification can alter the structure and regulate the function of hHsp70.

Pro-apoptotic and anti-proliferative effects of corn silk extract on human colon cancer cell lines.

Corn silk is an economically and nutritionally significant natural product as it represents a staple food for a large proportion of the world population. This study investigated the anticancer activity of corn silk extract in human colon cancer cells and human gastric cancer cells. Following treatment with corn silk extract, certain apoptosis-related events were observed, including inhibition of cell proliferation, loss of mitochondrial membrane potential (ΔΨm), release of Ca2+ and release of cytochrome c from the mitochondria into the cytosol. Our results revealed that corn silk extract inhibited the proliferation of cancer cells and increased the level of apoptosis in a concentration-dependent manner. Western blot analysis revealed that corn silk extract upregulated the levels of Bax, cytochrome c, caspase-3 and caspase-9, but downregulated the levels of B-cell lymphoma 2. These results suggest that corn silk extract may induce apoptosis through the mitochondria-mediated pathway.

The natural compound oblongifolin C inhibits autophagic flux and enhances antitumor efficacy of nutrient deprivation.

Metabolic stress induces autophagy as an alternative source of energy and metabolites. Insufficient autophagy in nutrient-deprived cancer cells would be beneficial for cancer therapy. Here, we performed a functional screen in search of novel autophagy regulators from natural products. We showed that oblongifolin C (OC), a natural small molecule compound extracted from Garcinia yunnanensis Hu, is a potent autophagic flux inhibitor. Exposure to OC results in an increased number of autophagosomes and impaired degradation of SQSTM1/p62. Costaining of GFP-LC3B with LysoTracker Red or LAMP1 antibody demonstrates that autophagosome-lysosome fusion is blocked by OC treatment. Furthermore, OC inhibits lysosomal proteolytic activity by altering lysosomal acidification and downregulating the expression of lysosomal cathepsins. Importantly, OC can eliminate the tolerance of cancer cells to nutrient starvation. Starvation dramatically increases the susceptibility of cancer cells to OC-induced CASP3-dependent apoptosis in vitro. Subsequent studies in xenograft mouse model showed that OC has anticancer potency as revealed by increased staining of cleaved CASP3, LC3 puncta, and SQSTM1, as well as reduced expression of lysosomal cathepsins. Combined treatment with OC and caloric restriction potentiates anticancer efficacy of OC in vivo. Collectively, these data demonstrated that OC is a novel autophagic flux inhibitor and might be useful in anticancer therapy.

Hypoxia-induced MIR155 is a potent autophagy inducer by targeting multiple players in the MTOR pathway.

Hypoxia activates autophagy, an evolutionarily conserved cellular catabolic process. Dysfunction in the autophagy pathway has been implicated in an increasing number of human diseases, including cancer. Hypoxia induces upregulation of a specific set of microRNAs (miRNAs) in a variety of cell types. Here, we describe hypoxia-induced MIR155 as a potent inducer of autophagy. Enforced expression of MIR155 increases autophagic activity in human nasopharyngeal cancer and cervical cancer cells. Knocking down endogenous MIR155 inhibits hypoxia-induced autophagy. We demonstrated that MIR155 targets multiple players in MTOR signaling, including RHEB, RICTOR, and RPS6KB2. MIR155 suppresses target-gene expression by directly interacting with their 3' untranslated regions (UTRs), mutations of the binding sites abolish their MIR155 responsiveness. Furthermore, by downregulating MTOR signaling, MIR155 also attenuates cell proliferation and induces G 1/S cell cycle arrest. Collectively, these data present a new role for MIR155 as a key regulator of autophagy via dysregulation of MTOR pathway.

A2B5 lineages of human astrocytic tumors and their recurrence.

Astrocytomas are very common intracranial glial cell neoplasms with an inherent tendency to progress. However, the heterogeneity of the morphological features and clinical behavior of the tumors makes accurate prognosis based on the histopathological grading system very difficult. Studies demonstrated that astrocytes have two distinctive cell lineages, and tumors arisen from these two astrocytic lineages have been speculated to have different biological and clinical manifestations. The present study aimed to delineate these two astrocytic lineages in human astrocytomas by using different immunohistochemical markers and to correlate the cell lineages of the tumors with their recurrence. Three markers were used, namely the A2B5 antigen, which is present in type 2 astrocytes but absent in type 1 astrocytes, glial fibrillary acidic protein (GFAP), a marker for astrocytes, and galactocerebroside (GC), a marker for oligodendrocytes. It was found that astrocytomas sharing the A2B5+ lineage (A2B5 positive and GFAP positive) have a significantly higher recurrence rate than the tumors of the A2B5- lineage (A2B5 negative and GFAP positive). Immunohistochemical staining and PCR-single-stranded conformational polymorphism analysis showed that p53 overexpression and p53 mutations were closely associated with the recurrent astrocytomas, and p53 abnormalities were more frequently detected in astrocytomas of the A2B5+ lineage. Quantification of proliferation by counting argyrophil nucleolar organizer regions (AgNORs) indicated a higher AgNOR count in the A2B5+ lineage than the A2B5- lineage. Our findings thus suggest that astrocytomas share similar antigenicity with astrocytes, and that the A2B5+ lineage exhibited a higher recurrence rate than the A2B5- lineage. The higher recurrence rate of the A2B5+ tumors may be in part related to the higher frequency of p53 abnormalities found in the tumors and the higher proliferative activity as reflected by the higher AgNOR count of the tumors.