PKCδ maintains phenotypes of tumor initiating cells through cytokine-mediated autocrine loop with positive feedback.

The existence of tumor initiating cells (TICs) has been emerged as a good therapeutic target for treatment of glioblastoma that is the most aggressive brain tumor with poor prognosis. However, the molecular mechanisms that regulate the phenotypes of TICs still remain obscure. In this study, we found that PKCδ, among PKC isoforms, is preferentially activated in TICs and acts as a critical regulator for the maintenance of TICs in glioblastoma. By modulating the expression levels or activity of PKCδ, we demonstrated that PKCδ promotes self-renewal and tumorigenic potentials of TICs. Importantly, we found that the activation of PKCδ persists in TICs through an autocrine loop with positive feedback that was driven by PKCδ/STAT3/IL-23/JAK signaling axis. Moreover, for phenotypes of TICs, we showed that PKCδ activates AKT signaling component by phosphorylation specifically on Ser473. Taken together, we proposed that TICs regulate their own population in glioblastoma through an autocrine loop with positive feedback that is driven by PKCδ-dependent secretion of cytokines.

Radiation promotes invasiveness of non-small-cell lung cancer cells through granulocyte-colony-stimulating factor.

Despite ionizing radiation (IR) is being widely used as a standard treatment for lung cancer, many evidences suggest that IR paradoxically promotes cancer malignancy. However, its molecular mechanisms underlying radiation-induced cancer progression remain obscure. Here, we report that exposure to fractionated radiation (2 Gy per day for 3 days) induces the secretion of granulocyte-colony-stimulating factor (G-CSF) that has been commonly used in cancer therapies to ameliorate neutropenia. Intriguingly, radiation-induced G-CSF promoted the migratory and invasive properties by triggering the epithelial-mesenchymal cell transition (EMT) in non-small-cell lung cancer cells (NSCLCs). By irradiation, G-CSF was upregulated transcriptionally by ß-catenin/TCF4 complex that binds to the promoter region of G-CSF as a transcription factor. Importantly, irradiation increased the stability of ß-catenin through the activation of PI3K/AKT (phosphatidylinositol 3-kinase/AKT), thereby upregulating the expression of G-CSF. Radiation-induced G-CSF is recognized by G-CSFR and transduced its intracellular signaling JAK/STAT3 (Janus kinase/signal transducers and activators of transcription), thereby triggering EMT program in NSCLCs. Taken together, our findings suggest that the application of G-CSF in cancer therapies to ameliorate neutropenia should be reconsidered owing to its effect on cancer progression, and G-CSF could be a novel therapeutic target to mitigate the harmful effect of radiotherapy for the treatment of NSCLC.

Modulation of dendritic cell function by the radiation-mediated secretory protein γ-synuclein.

Recently, γ-synuclein (SNCG), which is also known as breast cancer-specific gene-1, has been demonstrated to be an adverse and aggressive marker in breast cancer. In our previous study, SNCG was significantly upregulated in irradiated human breast cancer cells. The aim of this study was to investigate whether radiation-induced, tumor-derived SNCG can influence dendritic cell (DC) function in immune systems. The phenotypical and functional changes of DCs in the presence or absence of SNCG were investigated by FACS analysis, ELISA, and real-time PCR. The ability of SNCG-treated DCs to influence T cells was also examined by coculturing with T cells. The treatment of DCs with SNCG protein inhibited the surface expression of the co-stimulatory molecules CD40 and CD86, and decreased the mRNA levels of pro-inflammatory cytokines. The SNCG-treated DCs inhibited T-cell proliferation slightly, but distinctively increased the population of regulatory T cells. In addition, the production of TGF-ß from T cells was significantly increased when they were cocultured with SNCG-treated DCs. Taken together, these results demonstrate that tumor-derived SNCG contributes to immunosuppressive effects via the inhibition of DC differentiation and activation, thus making it a potential target for cancer treatment.

Investigation on antibacterial and antioxidant activities, phenolic and flavonoid contents of some thai edible plants as an alternative for antibiotics.

This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime) fruits and its leaves, Sesbania grandiflora L. (Agati sesbania) leaves, Piper sarmentosum Roxb (Wild betal) leaves, Curcuma domestica Valeton (Turmeric) roots, Morinda citrifolia L. (Beach mulberry) leaves, Cassia siamea britt (Siamea cassia) leaves, and Cocos nucifera L. (Coconut) peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC) were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, 135 µg/mL. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of 306 µg/mL and 183 µg/mL, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% (EC50) values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and 47.8 µg/mL, respectively. Flavonoid content of methanol extracts in S. grandiflora L. T was 22.5 µg/mL and the highest among plant extracts tested. These results indicated that C. aurantifolia Swingle, S. grandiflora L., P. sarmentosum Roxb, and C. domestica Valeton have antibacterial and antioxidant activities and can be used as alternative antibiotics or potential feed additives for the control of animal pathogenic bacteria.

Novel signaling axis for ROS generation during K-Ras-induced cellular transformation.

Reactive oxygen species (ROS) are well known to be involved in oncogene-mediated cellular transformation. However, the regulatory mechanisms underlying ROS generation in oncogene-transformed cells are unclear. In the present study, we found that oncogenic K-Ras induces ROS generation through activation of NADPH oxidase 1 (NOX1), which is a critical regulator for the K-Ras-induced cellular transformation. NOX1 was activated by K-Ras-dependent translocation of p47(phox), a subunit of NOX1 to plasma membrane. Of note, PKCδ, when it was activated by PDPK1, directly bound to the SH3-N domain of p47(phox) and catalyzed the phosphorylation on Ser348 and Ser473 residues of p47(phox) C-terminal in a K-Ras-dependent manner, finally leading to its membrane translocation. Notably, oncogenic K-Ras activated all MAPKs (JNK, ERK and p38); however, only p38 was involved in p47(phox)-NOX1-dependent ROS generation and consequent transformation. Importantly, K-Ras-induced activation of p38 led to an activation of PDPK1, which then signals through PKCδ, p47(phox) and NOX1. In agreement with the mechanism, inhibition of p38, PDPK1, PKCδ, p47(phox) or NOX1 effectively blocked K-Ras-induced ROS generation, anchorage-independent colony formation and tumor formation. Taken together, our findings demonstrated that oncogenic K-Ras activates the signaling cascade p38/PDPK1/PKCδ/p47(phox)/NOX1 for ROS generation and consequent malignant cellular transformation.

Claudin-1 induces epithelial-mesenchymal transition through activation of the c-Abl-ERK signaling pathway in human liver cells.

Claudins (CLDNs) are a family of integral membrane proteins central to the formation of tight junctions, structures that are involved in paracellular transport and cellular growth and differentiation, and are critical for the maintenance of cellular polarity. Recent studies have provided evidence that CLDNs are aberrantly expressed in diverse types of human cancers, including hepatocellular carcinomas (HCCs). However, little is known about how CLDN expression is involved in cancer progression. In this study, we show that CLDN1 has a causal role in the epithelial-mesenchymal transition (EMT) in human liver cells, and that the c-Abl-Ras-Raf-1-ERK1/2 signaling axis is critical for the induction of malignant progression by CLDN1. Overexpression of CLDN1 induced expression of the EMT-regulating transcription factors Slug and Zeb1, and thereby led to repression of E-cadherin, ß-catenin expression, enhanced expression of N-cadherin and Vimentin, a loss of cell adhesion, and increased cell motility in normal liver cells and HCC cells. In line with these findings, inhibition of either c-Abl or ERK clearly attenuated CLDN1-induced EMT, as evidenced by a reversal of N-cadherin and E-cadherin expression patterns, and restored normal motility. Collectively, these results indicate that CLDN1 is necessary for the induction of EMT in human liver cells, and that activation of the c-Abl-Ras-Raf-1-ERK1/2 signaling pathway is required for CLDN1-induced acquisition of the malignant phenotype. The present observations suggest that CLDN1 could be exploited as a biomarker for liver cancer metastasis and might provide a pivotal point for therapeutic intervention in HCC.

Randomized clinical trial: efficacy and safety of telbivudine and lamivudine in treatment-naïve patients with HBV-related decompensated cirrhosis.

Patients with decompensated cirrhosis owing to chronic hepatitis B viral (HBV) infection have a high morbidity/mortality rate, and the treatment remains a challenge. We studied the safety and efficacy of telbivudine and lamivudine in such patients. This noninferiority, double-blind trial randomized 232 treatment-naive patients with decompensated HBV (1:1) in 80 academic hospitals to receive once-daily telbivudine 600 mg or lamivudine 100 mg for 104 weeks. Primary composite endpoint was proportion of patients with HBV DNA <10 000 copies/mL, normal alanine aminotransferase (ALT) and Child-Turcotte-Pugh score improvement/stabilization at week 52. Response rates using a post hoc modified endpoint (HBV DNA <300 copies/mL [57 IU/mL] and ALT normalization) in intent-to-treat analysis (missing = failure) were 56.3%vs 38.0% after 76 weeks (P = 0.018) and 45.6%vs 32.9% after 104 weeks (P = 0.093) for telbivudine vs lamivudine. Telbivudine treatment was an independent predictive factor for HBV DNA <300 copies/mL and ALT normalization (P = 0.037). Response rates with protocol-defined composite endpoint in intent-to-treat analysis (M = F) were 56.2 vs 54.0% (noninferiority not achieved) and 39.1%vs 36.4% (noninferiority achieved) in telbivudine and lamivudine groups at 52 and 104 weeks. Telbivudine treatment was associated with a significant improvement in glomerular filtration rate compared to lamivudine treatment and was also associated with a trend for improvement in survival (87%vs 79%). No cases of lactic acidosis were reported. Telbivudine compared to lamivudine was associated with a higher rate of patients with both viral suppression and ALT normalization, a trend towards a higher rate of survival and significant improvement in glomerular filtration.

Impact of pretreatment thrombocytosis on blood-borne metastasis and prognosis of gastric cancer.

BACKGROUND: Thrombocytosis has been associated with malignancies and poor prognostic implications in cancer patients. In the present study the prognostic significance of pretreatment platelet (PLT) level was assessed with regard to recurrence and survival in patients with primary gastric adenocarcinoma. METHODS: The authors reviewed the prospective data of 1593 gastric cancer patients who received curative gastrectomy with extended lymphadenectomy. The correlations of PLT level with recurrence and overall survival were evaluated by both univariate and multivariate analyses. RESULTS: Thrombocytosis (≥ 40 × 10(4)/ µL), present in 6.4% of the patients prior to curative surgery, was more frequently associated with advanced T and N classification, larger tumor size, anemia, and leukocytosis (p < 0.05). In patients with pretreatment thrombocytosis compared to those without it, five-year survival rate was worse (56.9% vs. 65.5%; p = 0.043), and recurrence rate was higher mainly due to the frequent hematogenous spread (51.0% vs. 34.5%; p < 0.001). Furthermore, risk of blood-borne metastasis was almost three-fold higher in patients with pretreatment thrombocytosis (Odds ratio 2.83 [95% CI 1.67-4.77], p < 0.001). CONCLUSIONS: Pretreatment thrombocytosis correlated significantly with poor prognosis and can be used as an independent predictor of recurrence by blood-borne metastasis in gastric cancer.

c-Jun N-terminal kinase has a pivotal role in the maintenance of self-renewal and tumorigenicity in glioma stem-like cells.

Uncovering the mechanisms that govern the maintenance of stem-like cancer cells is critical for developing therapeutic strategies for targeting these cells. Constitutive activation of c-Jun N-terminal kinase (JNK) has been reported in gliomas and correlates with histological grade. Here, we found that JNK signaling is crucial for the maintenance of 'stemness' in glioma cells. Sphere-cultured glioma cells showed more phosphorylation of JNK compared with serum-containing monolayer cultures. Importantly, blockade of JNK signaling with SP600125 or small interfering RNAs targeting JNK1 or JNK2 significantly reduced the CD133(+)/Nestin(+) population and suppressed sphere formation, colony formation in soft agar, and expression of stem cell markers in sphere-cultured glioma cells. Intriguingly, sphere-cultured glioma cells exhibited enhanced expression of Notch-2, but not Notch-1, -3 or -4, and JNK inhibition almost completely abrogated this increase. Blocking the phosphoinoside 3-kinase (PI3K)/Akt pathway with LY294002 or si-Akt also suppressed the self-renewal of sphere-cultured glioma cells. PI3K, but not Akt, had a role as an upstream kinase in JNK1/2 activation. In addition, treatment with si-JNK greatly increased etoposide- and ionizing radiation (IR)-induced cell death in glioma spheres. Consistent with glioma cell lines, glioma stem-like cells isolated from primary patient glioma cells also had a higher activity of JNK and Notch-2 expression. Importantly, inhibition of JNK2 led to a decrease of Notch-2 expression and suppressed the CD133(+)/Nestin(+) cell population in patient-derived primary glioma cells. Finally, downregulation of JNK2 almost completely suppressed intracranial tumor formation by glioma cells in nude mice. Taken together, these data demonstrate that JNK signaling is crucial for the maintenance of self-renewal and tumorigenicity of glioma stem-like cells and drug/IR resistance, and can be considered a promising target for eliminating stem-like cancer cells in gliomas.

Coexistence of IgM antihepatitis A virus and IgM antihepatitis E virus in acute viral hepatitis: a prospective, multicentre study in Korea.

This study investigated the clinical, serological and molecular characteristics of coexistence of both immunoglobulin M (IgM) antihepatitis A virus (HAV) and IgM antihepatitis E virus (HEV) in acute viral hepatitis using a prospective, multicentre design. Among a total of 771 symptomatic cases with acute viral hepatitis enrolled in a Korean city from September 2006 to August 2008, coexistence of IgM anti-HAV and IgM anti-HEV was found in 43 patients (A+E group; 6%), while the existence of IgM anti-HAV alone was found in 595 patients (A group; 77%) and that of IgM anti-HEV alone in 14 patients (E group; 2%). Clinical data analysis and measurement of IgM and IgG anti-HEV were performed using two different commercial kits, and HAV RNA and HEV RNA were detected in available serum or stool samples. The clinical features of the A+E group were similar to those of the A group. HAV RNA detection rates in the A+E and A group were similar, while HEV RNA was detected only in the stool samples of the E group, not in the A+E group. Comparative testing of anti-HEV using two different ELISA kits showed markedly discordant results for IgM anti-HEV positivity and consistently low positivity for IgG anti-HEV in the A+E group. Coexistence of IgM anti-HEV measured by the Genelabs ELISA kit in the setting of hepatitis A appears to yield false-positive results in nonendemic areas of HEV infection. Diagnosis of hepatitis E using IgM anti-HEV should be made with caution.

Foetal rhabdomyoma with fine-needle aspirate cytology correlation.

A case of intermediate form of foetal rhabdomyoma with cytological correlation is reported in a ten-year-old girl who presented with a lump in the right neck region. Fine-needle aspirate of the lump was performed. Cytological findings were that of spindled cells and rhabdomyoblasts with abundant eosinophilic cytoplasm. The lesion was subsequently excised. Histology showed a well-circumscribed cellular lesion composed of oval- to spindle-shaped cells. There were interspersed immature skeletal muscle cells with uniform nuclei and eosinophilic tapered cytoplasm and ganglion-like rhabdomyoblasts. No marked cellular atypia or prominent mitoses was noted. Immunohistochemically, the tumour cells showed positivity for muscle specific actin, myoglobin and myogenin. There was focal positivity for desmin. The patient showed no evidence of local recurrence or metastasis after a 32-month follow-up. This is believed to be the first case report of cytological findings in an intermediate form of foetal rhabdomyoma.

An unusual case of an intramuscular lipoma of the pectoralis major muscle simulating a malignant breast mass.

INTRODUCTION: Intramuscular lipomas of the pectoralis major muscle are rare and may mimic malignant breast tumours. CLINICAL PICTURE: A 58-year-old Chinese woman presented with a 2- year history of an enlarging left breast mass. Clinical examination revealed a palpable hard mass in the left breast. TREATMENT: Standard mammographic views revealed a radiolucent mass deep in the left pectoralis major muscle. The mass was homogeneously hypoechoic with smooth margins on ultrasound. OUTCOME: Surgical excision of the mass was performed. Histological diagnosis was an intramuscular lipoma of the left pectoralis major muscle. CONCLUSIONS: Recognition of the radiolucent density and submammary location of a pectoralis major muscle lipoma is important as it allows the correct diagnosis to be made.

Caspase-dependent deubiquitination of monoubiquitinated nucleosomal histone H2A induced by diverse apoptogenic stimuli.

Enzymatic deubiquitination of mono-ubiquitinated nucleosomal histone H2A (uH2A) and H2B (uH2B) is closely associated with mitotic chromatin condensation, although the function of this histone modification in cell division remains ambiguous. Here we show that rapid and extensive deubiquitination of nucleosomal uH2A occurs in Jurkat cells undergoing apoptosis initiated by anti-Fas activating antibody, staurosporine, etoposide, doxorubicin and the proteasome inhibitor, N-acetyl-leucyl-leucyl-norlucinal. These diverse apoptosis inducers also promoted the accumulation of slowly migrating, high molecular weight ubiquitinated proteins and depleted the cellular pool of unconjugated ubiquitin. In apoptotic cells, ubiquitin was cleaved from uH2A subsequent to the appearance of plasma membrane blebbing, and deubiquitination of uH2A closely coincided with the onset of nuclear pyknosis and chromatin condensation. Nucleosomal uH2A deubiquitination, poly (ADP-ribose)polymerase (PARP) cleavage and chromatin condensation were prevented in cells challenged with apoptosis inducers by pretreatment with the pan-caspase inhibitor, zVAD-fmk, or by over-expressing anti-apoptotic Bcl-xL protein. These results implicate a connection between caspase cascade activation and nucleosomal uH2A deubiquitination. Transient transfection of 293 cells with the gene encoding Ubp-M, a human deubiquitinating enzyme, promoted uH2A deubiquitination, while an inactive mutated Ubp-M enzyme did not. However, Ubp-M-promoted deubiquitination of uH2A was insufficient to initiate apoptosis in these cells. We conclude that uH2A deubiquitination is a down-stream consequence of procaspase activation and that unscheduled cleavage of ubiquitin from uH2A is a consistent feature of the execution phase of apoptosis rather than a determining or initiating apoptogenic event. Nucleosomal uH2A deubiquitination may function as a cellular sensor of stress in situations like apoptosis through which cells attempt to preserve genomic integrity.

Molecular cloning of kpcA gene encoding a Kex2p-like endoprotease from Aspergillus nidulans.

We cloned and sequenced a gene, kpcA (Kex2p-like proprotein convertase A), from a genomic library of Aspergillus nidulans. The kpcA gene encodes an 820-residue protein, named KpcA, which contains a putative subtilisin-like catalytic domain (residues 136-466) homologous to that of the subtilisin serine protease family. KpcA shows 56, 73, and 47% amino acid identities with Saccharomyces cerevisiae Kex2p, Aspergillus niger KexB, and mouse furin within the subtilisin-like catalytic domain, respectively. The sequences around the proposed active site Asp, His, and Ser residues of KpcA are similar to those of other Kex2p family members. The KpcA mRNA transcript with an expected size of approximately 2.8 kb was detected in A. nidulans. The substrate specificity of KpcA, expressed in CHO cells, is similar to that of A. niger KexB and yeast Kex2p. We conclude that KpcA is a resident Kex2p-like proprotein that processes endoprotease in A. nidulans.

Induction of apoptotic cell death by a p53-independent pathway in neuronal SK-N-MC cells after treatment with 2,2',5,5'-tetrachlorobiphenyl.

Apoptotic cell death is an active process, which is a critical feature of the regulated development of multicellular organisms. Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants, some of which may be neurotoxic. This study investigates the 2,2', 5,5'-tetrachlorobiphenyl (PCB 52) induced apoptosis in human neuronal SK-N-MC cells, and the role of p53 in this response. Upon treatments with PCB 52, time- and concentration-dependent inhibition of the cell viability was observed. PCB 52 also caused apoptosis, as measured by cell morphology and DNA fragmentation. The capability of PCB 52 to induce apoptosis was associated with the proteolytic cleavage of specific target proteins, such as poly(ADP-ribose) polymerase (PARP) and beta-catenin proteins, suggesting the possible involvement of caspases. In general, DNA-damaging agents induce accumulation of the tumor suppressor protein p53, leading cells to either growth arrest in G1, or apoptosis. However, our data showed that both p53 and Bcl-2 protein levels were decreased in a time-dependent manner during apoptosis after exposure to PCB 52. These results suggest that PCB 52 induced a p53-independent apoptosis in these cells.

Increased expression and localization of a serine protease inhibitor, protease nexin-1 (PN-1), in the ovary and uterus during implantation in rat.

Protease nexin-1 (PN-1) is a serine protease inhibitor (serpin) that inactivates several proteases, including thrombin, urokinase, plasminogen activators (PA), and plasmin. It also plays a role in regulating proteolytic activity generated by PA system. PN-1 is known to be involved in tissue remodeling, cellular invasiveness, matrix degradation, and tumor growth. However, the role of PN-1 in female reproductive tracts, such as the uterus, ovary, and oviduct, during pregnancy is not known. The present study was designed to investigate the changes of PN-1 mRNA level and localization in the tracts during implantation and early pregnancy by using reverse transcription (RT)-polymerase chain reaction (PCR) and in situ hybridization. We found that PN-1 mRNA levels were coordinately regulated during early pregnancy in a stage- and tissue-specific manner, such that an increased expression of PN-1 gene appeared at the time of the implantation period in the uterus and ovary. Both the uterus and ovary synthesized PN-1 mRNA and their maximal PN-1 expression occurred on Day 6.5 postcoitum (p.c.). On 13.5 days of pregnancy, PN-1 level was low in the uterus and ovary. On the other hand, PN-1 mRNA in the oviduct did not show after 6.5 days of pregnancy. It appears that PN-1 mRNA in the uterus and ovary was highly regulated during early pregnancy, which might have an important role in implantation of rat blastocysts. PN-1 was localized in endometrial stromal cells of the uterus and in granulosa cells of the unstimulated primary follicles in the ovary during periimplantation period. Also, PN-1 mRNA expression was higher at implantation period than that at nonimplantation period of pregnancy. In conclusion, PN-1 is expressed in female reproductive tracts and highly regulated during implantation and early pregnancy.

Viral interferon regulatory factor 1 of Kaposi's sarcoma-associated herpesvirus binds to p53 and represses p53-dependent transcription and apoptosis.

Kaposi's sarcoma-associated herpesvirus (KSHV) is related to the development of Kaposi's sarcoma. Open reading frame K9 of KSHV encodes viral interferon regulatory factor 1 (vIRF1), which functions as a repressor of interferon- and IRF1-mediated signal transduction. In addition, vIRF1 acts as an oncogene to induce cellular transformation. Here we show that vIRF1 directly associates with the tumor suppressor p53 and represses its functions. The vIRF1 interaction domains of p53 are the DNA binding domain (amino acids [aa] 100 to 300) and the tetramerization domain (aa 300 to 393). p53 interacts with the central region (aa 152 to 360) of vIRF1. vIRF1 suppresses p53-dependent transcription and deregulates its apoptotic activity. These results suggest that vIRF1 may regulate cellular function by inhibiting p53.

Cutaneous Rosai-Dorfman disease--a pathologic review of 2 cases.

Rosai-Dorfman disease, also known as sinus histiocytosis with massive lymphadenopathy, is a rare but distinct clinicopathologic entity characterised histologically by a benign s histiocytic proliferation. Isolated involvement of extranodal sites without concomitant nodal disease is rare. We describe the pathological features of 2 cases of Rosai-Dorfman disease that were clinically confined to the skin. In both male adult Chinese patients, proliferation of histiocytes was accompanied by S-100 protein expression demonstrated immunohistochemically within the histiocytes. The pathology of Rosai-Dorfman disease and its microscopic differential diagnoses are discussed.

Prevention of cisplatin-DNA adduct repair and potentiation of cisplatin-induced apoptosis in ovarian carcinoma cells by proteasome inhibitors.

Histones H2A and H2B are known to be reversibly post-translationally modified by ubiquitination. We previously observed in cultured tumor cells that proteasome inhibition stabilizes polyubiquitinated proteins, depletes unconjugated ubiquitin, and thereby promotes the deubiquitination of nucleosomal histones in chromatin. Provocative indirect evidence suggests that histone ubiquitination/deubiquitination cycles alter chromatin structure, which may limit accessibility of DNA repair proteins to damaged sites. In the present study, we focused on the relationship between the ubiquitination status of histone H2A, the structure of chromatin, and the efficiency of nucleotide excision repair (NER) of cisplatin-DNA adducts in human ovarian carcinoma cells exposed to the antitumor drug cisplatin. Pretreating cells with the proteasome inhibitor lactacystin (LC) or N-acetyl-leucyl-leucyl-norleucinal (ALLnL) induced deubiquitination of ubiquitinated histone H2A (uH2A) and concomitantly promoted chromatin condensation, increased the extent of cisplatin-DNA adducts, and diminished NER-dependent repair of cisplatin-DNA lesions, compared with control cells treated with cisplatin alone. Both proteasome inhibitors also prevented the increase in ERCC-1 mRNA expression that occurs in cells exposed to cisplatin. Cells treated with the combination of ALLnL and cisplatin underwent apoptosis, as indicated by caspase-dependent poly(ADP-ribose) polymerase (PARP) cleavage, more quickly than cells treated with either agent alone. Additionally, the combination of ALLnL and cisplatin potently increased p53 levels in cell lysates and stimulated the binding of p53 to chromatin. Together, these observations suggest that proteasome inhibition may be exploited therapeutically for its potential to sensitize ovarian tumor cells to cisplatin.