CD4+Foxp3+ regulatory T-cell impairment by paclitaxel is independent of toll-like receptor 4.

Paclitaxel (PTX) is one of the most widely used clinical antitumour drugs in chemotherapy nowadays. Its effect on immune system has become a hot spot of research in recent years. Here, we demonstrated that PTX not only decreased the percentage of CD4+Foxp3+ regulatory T (Treg) cells both in vitro and in vivo but also impaired cell viability and cytokine production of Treg cells rather than CD4+Foxp3- effector T (Teff) cells. As PTX has been reported to mimic the activity of LPS to trigger the toll-like receptor 4 (TLR4) signalling pathway in macrophages, we investigated the possible role of TLR4 in the effect of PTX. However, although TLR4 expression on Treg cells was higher than that on Teff cells, the expression level remained unaltered in both Treg and Teff cells after PTX treatment. Surface molecules and activation markers in Treg and Teff cells did not change, either. Further study showed that the effect of PTX on TLR4-/- mice deficient in TLR4 signalling was similar to that on C57BL/6 mice both in vivo and in vitro. These data indicate that the selective impairment of Treg cells by PTX is independent of TLR4.

Evaluation and validation of a PulseNet standardized pulsed-field gel electrophoresis protocol for subtyping Vibrio parahaemolyticus: an international multicenter collaborative study.

The pandemic spread of Vibrio parahaemolyticus is an international public health issue. Because of the outbreak potential of the organism, it is critical to establish an internationally recognized molecular subtyping protocol for V. parahaemolyticus that is both rapid and robust as a means to monitor its further spread and to guide control measures in combination with epidemiologic data. Here we describe the results of a multicenter, multicountry validation of a new PulseNet International standardized V. parahaemolyticus pulsed-field gel electrophoresis (PFGE) protocol. The results are from a composite analysis of 36 well-characterized V. parahaemolyticus isolates from six participating laboratories, and the isolates represent predominant serotypes and various genotypes isolated from different geographic regions and time periods. The discriminatory power is very high, as 34 out of 36 sporadic V. parahaemolyticus strains tested fell into 34 distinguishable PFGE groups when the data obtained with two restriction enzymes (SfiI and NotI) were combined. PFGE was further able to cluster members of known pandemic serogroups. The study also identified quality measures which may affect the performance of the protocol. Nonadherence to the recommended procedure may lead to high background in the PFGE gel patterns, partial digestion, and poor fragment resolution. When these quality measures were implemented, the PulseNet V. parahaemolyticus protocol was found to be both robust and reproducible among the collaborating laboratories.

MicroRNA-222 contributed to cell proliferation, invasion and migration via regulating YWHAG in osteosarcoma.

OBJECTIVE: The aim of this study was to investigate the role of microRNA-222 (miR-222) in osteosarcoma (OS), and to further explore the potential molecular mechanism. PATIENTS AND METHODS: We measured the level of miR-222 in OS tissues and cell lines using quantitative Real-time polymerase chain reaction. Synthesized miR-222 mimics or inhibitors were obtained to up-regulate or down-regulate the expression of miR-222 in U2OS or Saos2 cells. Cell counting kit-8 (CCK8) and colony formation assay were employed to detect the ability of cell proliferation, and transwell assay was used to confirm the ability of cell invasion. Furthermore, luciferase assay and Western blot were applied to verify the target of miR-222 in OS. RESULTS: The level of miR-222 in OS tumor tissue samples was significantly lower than that in normal group. Over-expression of miR-222 decreased cell proliferation and invasion in U2OS cells while knockdown of miR-222 promoted cell growth and metastasis in Saos2 cells. Furthermore, YWHAG was found to be a candidate target of miR-222 using several databases. Elevated level of miR-222 inhibited YWHAG expression while reduced miR-222 promoted YWHAG expression. Also, up-regulation of YWHAG restored the inhibiting effect of miR-222 mimics. CONCLUSIONS: We identified for the first time that the expression level of miR-222 was reduced in OS tissues as well as in OS cell lines. miR-222 could inhibit cell proliferation and invasion via down-regulating YWHAG. These data could provide a potential target for the biological treatment of OS.

Somatic mutation of human immunoglobulin V genes in the X-linked HyperIgM syndrome.

Somatic mutation of Ig variable regions occurs prominently in germinal centers, but it has been debated whether the mutation process initiates in germinal centers or is activated before germinal center entry of B cells. We have analyzed for the presence of somatic mutation in Ig gene rearrangements of the nonpolymorphic human VH6 gene in the X-linked HyperIgM syndrome, which is associated with defective CD40 ligand expression and absence of germinal centers and generation of memory B lymphocytes. IgM and rare IgG VH6 productive rearrangements were isolated from PBL of patients with X-linked HyperIgM syndrome. Although the majority of both the IgM and IgG VH6 rearrangements had a germline VH6 sequence, 7 of 102 VH6 IgM and 1 of 6 IgG rearrangements had a mutated VH6 gene. The mutation frequency (mutations/bp) was 1.4% with a range of 2-9 mutations per clone, a mutation frequency lower, however, than that observed in IgM (3.2%) and IgG (5.4%) VH6 rearrangements of normal individuals. These results suggest that somatic mutation may be initiated in a CD40 ligand-independent pathway before entry of B cells into germinal centers, but fails to achieve the high mutation frequency observed in the presence of germinal centers.

DNA hypomethylation is crucial for apoptotic DNA to induce systemic lupus erythematosus-like autoimmune disease in SLE-non-susceptible mice.

OBJECTIVES: Systemic lupus erythematosus (SLE) is characterized by serological presence of anti-double-stranded DNA (dsDNA) antibodies and its pathogenesis remains unclarified. Our previous work found that syngeneic activated lymphocyte-derived DNA (ALD-DNA) induced SLE-like autoimmune disease in the SLE-non-prone BALB/c mice. Here, the biological and chemical characteristics of the somatic DNA were focused upon to investigate their contribution to the autoimmunity induction to provide clues for the understanding of the pathogenesis of SLE in non-susceptible strains. METHODS: Induction of anti-dsDNA antibodies, glomerulonephritis and proteinuria was evaluated in BALB/c mice after subcutaneous immunization with apoptotic DNA (annexin-V+) extracted from concanavalin A or UV-treated apoptotic splenocytes or necrotic DNA from necrotic splenocytes. The hypomethylated apoptotic DNA and the normal DNA were then methylated and demethylated, respectively, by CpG methylase or 5-azacytidine treatment to re-evaluate their immunogenicity in BALB/c mice. RESULTS: It was apoptotic but not necrotic DNA that induced SLE-like autoimmune disease and the level of apoptotic DNA was associated with the level of anti-dsDNA antibodies. The apoptotic DNA exhibited significantly lower methylation levels than the normal DNA. Methylation of the hypomethylated apoptotic DNA significantly impaired its ability to induce anti-dsDNA antibodies and proteinuria, while demethylation of the normal or necrotic DNA endowed them with the immunogenicity to induce the SLE-like syndrome. CONCLUSIONS: Our study provides direct evidence showing that DNA hypomethylation is essential for apoptotic DNA to induce SLE-like autoimmune disease in non-susceptible mice, which may help in elucidating the pathogenesis of SLE.

Time-to-Event Analysis of Polatuzumab Vedotin-Induced Peripheral Neuropathy to Assist in the Comparison of Clinical Dosing Regimens.

Polatuzumab vedotin, an antibody-drug conjugate containing monomethyl auristatin E, was associated with an incidence of grade ≥2 peripheral neuropathy (PN) of 55-72% in patients with indolent non-Hodgkin lymphoma in a phase II study, when dosed 1.8-2.4 mg/kg every 3 weeks until progression or for a maximum of 17 cycles. To quantify the correlation of conjugate exposure and treatment duration with PN risk, a time-to-event model was developed using data from phase I and II studies. The model suggested that PN risk increased with conjugate exposure and treatment cycles, and a trend for increased risk with body weight and albumin concentration. When capping the treatment duration to six to eight cycles, the risk ratio of a dose of 2.4 mg/kg vs. 1.8 mg/kg was ≥1.29; the predicted incidence of grade ≥2 PN at 1.8-2.4 mg/kg dose levels was 17.8-37.2%, which is comparable with other antimicrotubule agents for lymphoma treatment.

Coexpression of vimentin and keratins by human melanoma tumor cells: correlation with invasive and metastatic potential.

BACKGROUND: Several protein markers, including vimentin, have been used to diagnose human melanoma. Because melanoma often has metastasized by the time of diagnosis, early markers prognostic for metastatic potential need to be identified. Commonly, vimentin is found in mesenchymal cells, and keratins are present in epithelial cells, but recent studies report coexpression of vimentin and keratin(s) in epithelial and nonepithelial neoplasms, including some melanomas. PURPOSE: Our purpose was to determine whether coexpression of vimentin and keratin(s) is correlated with tumor cell invasion and metastatic behavior. METHODS: We evaluated nine human melanoma cell lines expressing vimentin and other markers of aggressive tumor behavior (HMB-45, S-100, HLA-ABC class I and HLA-DR class II histocompatibility antigens, and K8 and K18 keratins). Levels of K8 and K18 keratins were determined in the highly metastatic C8161 cell line, the poorly metastatic A375P line, and the moderately metastatic A375M line. To determine whether the presence of keratin affects migratory ability, we altered the conformational structure of keratin filaments in C8161 cells by transfection with a mutant K18 complementary DNA. We also determined messenger RNA levels of human type IV collagenase, an enzyme marker for invasion and metastasis. RESULTS: In A375P cells, two-dimensional electrophoresis with Coomassie-stained gels, immunoblotting, and immunofluorescence staining showed no detectable levels of K8 or K18. A375M cells showed low levels of K8 and K18 by Western and Northern blotting, with a distinctive fluorescent subpopulation of cells. In comparison, K8 and K18 levels in C8161 cells were high in all cells. Type IV collagenase messenger RNA levels were lowest in A375P cells and highest in C8161 cells, correlating with invasive ability in vitro and metastatic potential in athymic nude mice. The transfectant clones C1070-10 and C1070-14 derived from the C8161 parent line showed dramatic morphological changes, disrupted keratin filaments, and decreased invasive and metastatic potential directly correlated with a reduction in migratory activity. CONCLUSION: These findings show a correlation between the coexpression of vimentin with K8 and K18 keratins and the invasive and metastatic behavior of three representative human melanoma cell lines.

v-jun oncogene suppresses both phorbol ester-induced cell invasion and stromelysin gene expression in a mouse papilloma cell line.

The viral jun (v-jun) oncogene encodes a transcription factor that can participate in the transactivation of genes through the AP-1 complex. Evidence indicates that the ability of v-jun to transform cells and stimulate transcription depends on the cell type. We have asked whether expression of the v-jun gene in benign tumor forming mouse keratinocytes that already express an activated c-rasHa oncogene would cause malignant progression. Our results showed that the v-jun transfection did not result in malignant progression; instead, we made the unexpected observation that the ability of these cells to invade reconstituted basement membrane matrix (in vitro) in response to the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate, was suppressed. This phenomenon could, in part, be explained by the suppression of the induction by phorbol ester of expression of the metalloproteinase, stromelysin (transin). Of interest was the finding that 12-O-tetradecanoylphorbol-13-acetate induction of other cellular genes known to be regulated by AP-1 was not inhibited in the benign tumor cells expressing v-jun.

Integrated Two-Analyte Population Pharmacokinetic Model for Antibody-Drug Conjugates in Patients: Implications for Reducing Pharmacokinetic Sampling.

An integrated pharmacokinetics (PK) model that simultaneously describes concentrations of total antibody (Tab) and antibody-conjugated monomethyl auristatin E (acMMAE) following administration of monomethyl auristatin E (MMAE)-containing antibody-drug conjugates (ADCs) was developed based on phase I PK data with extensive sampling for two ADCs. Two linear two-compartment models that shared all parameters were used to describe the PK of Tab and acMMAE, except that the deconjugation rate was an additional clearance pathway included in the acMMAE PK model compared to Tab. Further, the model demonstrated its ability to predict Tab concentrations and PK parameters based on observed acMMAE PK and various reduced or eliminated Tab PK sampling schemes of phase II data. Thus, this integrated model allows for the reduction of Tab PK sampling in late-phase clinical development without compromising Tab PK characterization.

Anti-CD22 and anti-CD79B antibody drug conjugates are active in different molecular diffuse large B-cell lymphoma subtypes.

Antibody drug conjugates (ADCs), in which cytotoxic drugs are linked to antibodies targeting antigens on tumor cells, represent promising novel agents for the treatment of malignant lymphomas. Pinatuzumab vedotin is an anti-CD22 ADC and polatuzumab vedotin an anti-CD79B ADC that are both linked to the microtubule-disrupting agent monomethyl auristatin E (MMAE). In the present study, we analyzed the activity of these agents in different molecular subtypes of diffuse large B-cell lymphoma (DLBCL) both in vitro and in early clinical trials. Both anti-CD22-MMAE and anti-CD79B-MMAE were highly active and induced cell death in the vast majority of activated B-cell-like (ABC) and germinal center B-cell-like (GCB) DLBCL cell lines. Similarly, both agents induced cytotoxicity in models with and without mutations in the signaling molecule CD79B. In line with these observations, relapsed and refractory DLBCL patients of both subtypes responded to these agents. Importantly, a strong correlation between CD22 and CD79B expression in vitro and in vivo was not detectable, indicating that patients should not be excluded from anti-CD22-MMAE or anti-CD79B-MMAE treatment because of low target expression. In summary, these studies suggest that pinatuzumab vedotin and polatuzumab vedotin are active agents for the treatment of patients with different subtypes of DLBCL.

Acidic pH enhances the invasive behavior of human melanoma cells.

As a consequence of poor perfusion and elevated acid production, the extracellular pH (pHex) of tumors is generally acidic. Despite this, most in vitro experiments are still performed at the relatively alkaline pHex of 7.4. This is significant, because slight changes in pHex can have profound effects on cell phenotype. In this study we examined the effects of mildly acidic conditions on the in vitro invasive potential of two human melanoma cell lines; the highly invasive C8161, and poorly invasive A375P. We observed that culturing of either cell line at acidic pH (6.8) caused dramatic increases in both migration and invasion, as measured with the Membrane Invasion Culture System (MICS). This was not due to a direct effect of pH on the invasive machinery, since cells cultured at normal pH (7.4) and tested at acidic pH did not exhibit increased invasive potential. Similarly, cells cultured at acidic pH were more aggressive than control cells when tested at the same medium pH. These data indicate that culturing of cells at mildly acidic pH induces them to become more invasive. Since acid pH will affect the intracellular pH (pHin) and intracellular calcium ([Ca2+]in), we examined the effect of these parameters on invasion. While changes in [Ca2+]in were not consistent with invasive potential, the changes in pHin were. While these conditions decrease the overall amount of gelatinases A and B secreted by these cells, there is a consistent and significant increase in the proportion of the activated form of gelatinase B.

Suppression of tumor angiogenesis by targeting the protein neddylation pathway.

Inhibition of protein neddylation, particularly cullin neddylation, has emerged as a promising anticancer strategy, as evidenced by the antitumor activity in preclinical studies of the Nedd8-activating enzyme (NAE) inhibitor MLN4924. This small molecule can block the protein neddylation pathway and is now in clinical trials. We and others have previously shown that the antitumor activity of MLN4924 is mediated by its ability to induce apoptosis, autophagy and senescence in a cell context-dependent manner. However, whether MLN4924 has any effect on tumor angiogenesis remains unexplored. Here we report that MLN4924 inhibits angiogenesis in various in vitro and in vivo models, leading to the suppression of tumor growth and metastasis in highly malignant pancreatic cancer, indicating that blockage of angiogenesis is yet another mechanism contributing to its antitumor activity. At the molecular level, MLN4924 inhibits Cullin-RING E3 ligases (CRLs) by cullin deneddylation, causing accumulation of RhoA at an early stage to impair angiogenic activity of vascular endothelial cells and subsequently DNA damage response, cell cycle arrest and apoptosis due to accumulation of other tumor-suppressive substrates of CRLs. Furthermore, we showed that inactivation of CRLs, via small interfering RNA (siRNA) silencing of its essential subunit ROC1/RBX1, recapitulates the antiangiogenic effect of MLN4924. Taken together, our study demonstrates a previously unrecognized role of neddylation in the regulation of tumor angiogenesis using both pharmaceutical and genetic approaches, and provides proof of concept evidence for future development of neddylation inhibitors (such as MLN4924) as a novel class of antiangiogenic agents.

Insulin-like growth factor binding protein-3 (IGFBP-3) acts as an invasion-metastasis suppressor in ovarian endometrioid carcinoma.

Metastasis and invasion occur in the majority of epithelial ovarian carcinoma at diagnosis. To delineate the molecular signature in ovarian cancer invasion, we established and characterized a human ovarian endometrioid carcinoma (EC) cell line OVTW59-P0 and its invasion-related sublines (P1-P4, in the order of increasing invasive activity). P4 showed faster migration and larger xenograft formation with metastasis than P0. By microarray analysis of different gene expression among P0-P4 sublines, one group of gene was found negatively correlated with cancer invasion. Among these genes, IGFBP-3 was identified as one of the most remarkably suppressed gene that showed lower gene expression in P4 than P0. Re-expression of IGFBP-3 in P4 effectively inhibited cell migration, invasion and metastasis, but did not affect cell proliferation. In 35 patients with EC tumors, low IGFBP-3 expression correlated clinically with higher tumor grade, advanced stage and poor survival. Our results provide evidence and indicate that IGFBP-3 plays an important role as an invasion-metastasis suppressor in ovarian EC.

Induction of systemic lupus erythematosus-like syndrome in syngeneic mice by immunization with activated lymphocyte-derived DNA.

OBJECTIVES: Systemic lupus erythematosus (SLE) is the prototype of autoimmune disease and the mechanisms underlying the disease have not yet been elucidated. Thus, animal models of SLE would facilitate investigation of pathogenetic mechanisms involved in the development of the disease. This study characterizes a murine model of SLE-like syndrome induced by syngeneic activated lymphocyte-derived DNA (referred to as ALD DNA). METHODS: Normal BALB/c mice were immunized subcutaneously with highly purified ALD DNA. Anti-double-stranded DNA (anti-dsDNA) antibodies were determined by enzyme-linked immunosorbent assay. Other SLE-associated autoantibodies were examined by indirect immunofluorescence and anti-ENA (extractable nuclear antigen) profile assay. Pathological changes were analysed by light microscopy and electron microscopy. Kidney cryostat sections were viewed by immunofluorescence for the presence of glomerular IgG and C3 deposits. Proteinuria was measured by Coomassie brilliant blue assay. RESULTS: High levels of anti-dsDNA antibodies and other autoantibodies frequently appearing in SLE were detectable in the sera of ALD DNA-immunized mice. Glomerulonephritis and glomerular deposition of IgG plus C3 were observed in the kidney sections. Moreover, proteinuria was seen in the immunized mice. CONCLUSIONS: SLE-like syndrome can be induced by ALD DNA in normal mice. This induced model may be useful for elucidating the mechanisms involved in autoimmunity to DNA and the development of SLE.

Detection of a protein which binds specifically to the upstream region of the pcbAB gene in Penicillium chrysogenum.

The upstream region of the pcbAB gene from Penicillium chrysogenum was screened for protein-binding sites using an electromobility shift assay. A specific protein/DNA interaction was detected within a fragment covering the region -387 to -242 relative to the pcbAB translational start codon. The appearance of this protein and pcbAB mRNA in culture extracts occurred at the same time point in fermentations, suggesting that the protein might be a transcription activator. The putative upstream activating sequence was located more precisely using cross-competition assays. These indicated the involvement of the 7-bp motif TGCCAAG in the binding of the protein.

Extracellular pH affects regulation of the pcbAB gene in Penicillium chrysogenum.

The effect of extracellular pH and dissolved oxygen on regulation of the pcbAB gene in P. chrysogenum was examined, using Northern analysis and a reporter gene fusion. It was found that ambient pH markedly affected levels of pcbAB mRNA whereas maintenance of dissolved oxygen concentration above 10% had no detectable effect. The presence of a DNA-binding protein, which binds upstream of the pcbAB translational start codon, was also related to ambient pH. In all fermentations, pcbAB mRNA was most abundant at around the late exponential/early stationary phase of a culture.

Experimental coexpression of vimentin and keratin intermediate filaments in human melanoma cells augments motility.

Intermediate filaments have been used as cell-type-specific markers in differentiation and pathology; however, recent reports have demonstrated the coexpression of vimentin (a mesenchymal marker) and keratins (epithelial markers) in numerous neoplasms, including melanoma, which has been linked to metastatic disease. To test the hypothesis that coexpression of vimentin and keratins by melanoma cells contributes to a more migratory and invasive phenotype, we co-transfected a vimentin-positive human melanoma cell line, A375P (of low invasive ability), with cDNAs for keratins 8 and 18. The resultant stable transfectants expressed vimentin- and keratin-positive intermediate filaments showed a two- to threefold increase in their invasion of basement membrane matrix and migration through gelatin in vitro. These findings were further corroborated by video cinematography. During attachment and spreading on fibronectin, the transfectants containing vimentin and keratins 8 and 18 demonstrated an increase in focal adhesions that stained positive for beta 1 integrin and phosphotyrosine, along with enhanced membrane ruffling and actin stress fiber formation. From these data, we postulate that coexpression of vimentin and keratins results in increased cytoskeletal interactions at focal contacts within extracellular matrices involving integrin cell signaling events, which contributes to a more migratory behavior.

Expression of complete keratin filaments in mouse L cells augments cell migration and invasion.

Intermediate filament proteins have been used to diagnose the origin of specific cells. Classically, vimentin is found in mesenchymal cells, and keratins are present in epithelial cells. However, recent evidence suggests that the coexpression of these phenotype-specific proteins augments tumor cell motility, and hence, metastasis. In the present study, we used the mouse L-cell model to determine if a direct correlation exists between the expression of additional keratins in these cells, which normally express only vimentin, and their migratory ability. Mouse L cells were transfected with human keratins 8, 18, and both 8 and 18. The results indicate that the cells expressing complete keratin filaments have a higher migratory and invasive ability (through extracellular matrix-coated filters) compared with the parental and control-transfected clones. Furthermore, there is an enrichment of keratin-positive cells from a heterogeneous population of L clones selected over serial migrations. This migratory activity was directly correlated with the spreading ability of the cells on Matrigel matrix, in which the keratin-positive transfectants maintain a round morphology for a longer duration, compared with the other L-cell populations. Collectively, these data suggest that keratins may play an important role(s) in migration, through a special interaction with the extracellular environment, thereby influencing cell shape.