MiR-15b facilitates breast cancer progression via repressing tumor suppressor PAQR3

OBJECTIVE

Recently, breast cancer (BC) has become a common tumor that threatens the physical and mental health of women. Microribonucleic acids (miRNAs) have been chosen as a study object because of their roles in various cancers, including BC. Here, we mainly study the role of miR-15b in BC progression and its underlying mechanism.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine the level of MiR-15b expression in 60 pairs of BC tissues and para-cancerous specimens, and the relationship between MiR-15b level and clinical features of BC patient prognosis was analyzed. MiR-15b and PAQR3 level in BC tissues and cells was tested by Western blot.

RESULTS

The results showed that miR-15b expression was higher and PAQR3 level was lower in BC. The identification of PAQR3 as a target of miR-15b in BC was carried out by Luciferase reporter assay and the results stated that the Luciferase activity was reduced by miR-15b mimic, indicating PAQR3 being a target of miR-15b in BC. Transwell assay was used for examining BC cell migration and invasion and found that miR-15b could promote BC cell migration and invasion, while the effect of PAQR3 was inhibition. Furthermore, PAQR3 could reverse the promotion effect of miR-15b on BC cell migratory and invasive ability. In addition, miR-15b expression was negatively correlated with PAQR3 performed by regression analysis.

CONCLUSIONS

Our data stated that miR-15b could facilitate BC progression via repressing tumor suppressor PAQR3, indicating that miR-15b/PAQR3 axis provided a therapeutic target for treating BC.

MicroRNA-486 inhibits cell proliferation, invasion and migration via down-regulating the TENM1 expressions and affecting ERK and Akt signaling pathways and epithelial-to-mesenchymal transition in papillary thyroid carcinoma

OBJECTIVE

Papillary thyroid carcinoma (PTC) is one of the general thyroid malignancies. Recently, microRNAs (miRNAs) have identified as pivotal gene regulators in PTC tumorigenesis. The aim of this study was to investigate the role of miR-486 in PTC and its underlying mechanism.

PATIENTS AND METHODS

Fifty-six pairs of PTC tissue and matched normal tissue samples were collected from PTC patients who underwent surgery at our hospital from March 2015 to September 2017. Human thyroid epithelial cell line Nthy-ori3-1and PTC cell lines (BCPAP, K1, HTH83, and TPC-1) were cultured. The mRNA and protein expression level were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot, respectively. Additionally, the proliferation and migration abilities were checked by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method and transwell assay, respectively. Furthermore, dual-luciferase reporter assay was performed to confirm the combination of miR-486 and TENM1. Xenograft Model experiments were performed to assess the effects of miR-486 on tumor growth in vivo.

RESULTS

MiR-486 expression was significantly reduced in PTC, which was associated with the poorer clinicopathologic characteristics and overall survival (OS) of PTC patients. Moreover, miR-486 restoration in PTC cells was confirmed to markedly inhibit proliferation, invasion, and migration via the regulation of extracellular-signal-regulated kinase (ERK) and protein kinase B (Akt) signaling pathways and epithelial-mesenchymal transition (EMT). In the meantime, teneurin transmembrane protein 1 (TENM1) was identified as a direct functional target for miR-486 in PTC cells on the basis of bioinformatic analysis and luciferase reporter assays. Additionally, we also verified that miR-486 restoration could prominently repress the PTC growth in vivo.

CONCLUSIONS

MiR-486 exerted anti-tumor functions in PTC progression and served as promising biomarkers for the PTC treatment.

LncRNA SNHG20 promotes the development of laryngeal squamous cell carcinoma by regulating miR-140

OBJECTIVE

This study aims to investigate the expression level of long non-coding RNA (lncRNA) SNHG20 in laryngeal squamous cell carcinoma (LSCC), and to explore further whether it can promote the development of LSCC by regulating microRNA-140 (miR-140).

PATIENTS AND METHODS

Expression levels of SNHG20 in 56 pairs of LSCC tissues and adjacent normal tissues were measured by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The relationship between SNHG20 expression with pathological parameters and the prognosis of LSCC was analyzed. Besides, the SNHG20 expression in LSCC cells was also analyzed by qRT-PCR. The SNHG20 knockdown and overexpression model were constructed by lentivirus transfection in AMC-HN-8 and Hep-2 cells. Cell counting kit-8 (CCK-8) and 5-Ethynyl-2'-deoxyuridine (EdU) assay were used to analyze the effect of SNHG20 on the biological function of LSCC cells. Finally, the dual-luciferase reporter gene assay was performed to explore the potentials of SNHG20 and miR-140 in LSCC.

RESULTS

The SNHG20 expression in LSCC tissues or cells remarkably increased than controls, and the difference was statistically significant. The LSCC patients with the high expression level of SNHG20 were more likely to develop advanced tumor compared with patients with low expression of SNHG20. Moreover, the LSCC patients with the high expression level of SNHG20 had a shorter overall survival than those with low level. The cell proliferation ability significantly decreased in the SNHG20 knockdown group, while notably increased in SNHG20 overexpression group. MiR-140 was negatively correlated with SNHG20 in LSCC tissues and cells. Dual-luciferase reporter gene assay showed that SNHG20 could be targeted by miR-140 through a certain binding site. The cell rescue experiment also indicated that there was a mutual regulation between SNHG20 and miR-140, which could together affect the malignant progression of LSCC.

CONCLUSIONS

We showed that the expression levels of SNHG20 in LSCC tissues or cell lines significantly increased and was associated with advanced tumor staging and undesirable prognosis of LSCC. In addition, SNHG20 could promote the malignant progression of LSCC.

[The current status and applications of implantable bone-conduction devices]

Implantable bone-conduction devices are characterized by the fact that the vibration is transmitted through bone conduction. The technology and surgical techniques in the application of implantable bone-conduction devices have developed considerably in recent years, experiencing a transformation from percutaneous to transcutaneous implantation. This article reviewed current developments in the types, surgical indications, and complications, as well as compared between the various bone-conduction devices to provid references for clinical application.

[Effects of rabbit adipose-derived mesenchymal stem cells on the healing of skin deep partial-thickness scald wound of rabbit]

OBJECTIVE

To investigate the effects of local injection of rabbit adipose-derived mesenchymal stem cells (ADSCs) on the healing of skin deep partial-thickness scald wound of rabbit.

METHODS

ADSCs were isolated from adipose tissue of one New Zealand rabbit and then sub-cultured. ADSCs of the third passage were used in the following experiments. Twenty-four rabbits were divided into ADSCs group (n=12) and control group (n=12) according to the random number table, and one deep partial-thickness scald wound with diameter of 5 cm on the two sides of the back near the buttocks was made. From post injury day (PID) 2, 2 mL suspension of EdU-labeled ADSCs with the number of 5×10(5) per mL was subcutaneously injected in wounds of rabbits in ADSCs group, while the rabbits in control group were given 2 mL serum-free DMEM until the wounds were healed. Wound healing processes of rabbits in two groups were observed every day, and the healing time was recorded. On PID 7, 14, 21, and 28, areas of wound of three rabbits in two groups were measured and the healing rates were calculated, respectively. The healed wound tissue was harvested to observe the morphology by HE staining, and the expression of collagen fiber was observed by Masson staining. The distribution of EdU-labeled ADSCs in healed wound tissue on PID 28 was observed by inverted fluorescence microscope. The expressions of vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) of healed wound tissue on PID 7, 14, and 21 were detected by enzyme-linked immunosorbent assay. Data were processed with analysis of variance of factorial design and paired samples t test.

RESULTS

(1) The wound healing time of rabbits in ADSCs group was (19.5±1.1) d post injury, which was significantly shorter than that in control group [(23.3±1.5) d, t=4.50, P<0.05]. On PID 7, wounds of rabbits in two groups were dry with no obvious exudation, and redness and swelling around wounds disappeared gradually, the wound healing rate of rabbits in ADSCs group was (15.1±2.4)%, which was close to that in control group [(13.7±3.1)%, t=1.20, P>0.05]. On PID 14, wounds of rabbits in ADSCs group were dry and scabbed obviously, and the wound healing rate was (73.1±5.7)%, while wounds of rabbits in control group were little scabbed with little exudation, and the wound healing rate was significantly lower than that in ADSCs group [(52.9±5.1)%, t=8.06, P<0.01]. On PID 21, wounds of rabbits in ADSCs group were generally healed, and the wound healing rate was (95.6±3.0)%, while a few wounds still existed in rabbits of control group, and the wound healing rate was significantly lower than that in ADSCs group [(78.6±3.7)%, t=9.73, P<0.01]. On PID 28, wounds of rabbits in two groups were totally healed with the healing rate of 100%, and texture and microvascular responses of healed wound tissue in ADSCs group were better than those in control group. (2) On PID 7, fibroblasts in healed wound tissue of rabbits in two groups were all increased, and there were little vascular and collagen fiber proliferation with no obvious differences. On PID 14, the number of fibroblasts in healed wound tissue of rabbits in ADSCs group was more than that in control group, and the collagen fibers in healed wound tissue of rabbits in ADSCs group were arranged in dense and uniform, while those in control group were sparse and irregular. On PID 21, skin layers were differentiated in healed wound tissue of rabbits in two groups, and collagen fibers in healed wound tissue of rabbits in ADSCs group were still denser than that in control group. On PID 28, newborn skin was well differentiated in healed wound tissue of rabbits in ADSCs group, which was better than that in control group. There were a lot of thick collagen fibers in healed wound tissue of rabbits in two groups, and EdU-labeled ADSCs were involved in skin texture of rabbits in ADSCs group. (3) The expressions of VEGF and EGF in healed wound tissue of rabbits in two groups were similar on PID 7 (with t values respectively 0.70 and 0.91, P values above 0.05), which in ADSCs group were significantly higher than those in control group on PID 14 and 21 (with t values from 2.85 to 4.81, P values below 0.01).

CONCLUSIONS

The transplantation of ADSCs can promote the wound healing of skin deep partial-thickness scald wound of rabbit and shorten the wound healing time.

Reciprocal regulation of miRNAs and piRNAs in embryonic development

MicroRNAs (miRNAs) and piwi-interacting RNAs (piRNAs) are two classes of small noncoding RNAs, both of which play roles in regulating tissue development. It is unknown whether these distinct classes of noncoding RNAs can regulate one another. Here we show that ectopic expression of miR-17 inhibited mouse fertility and early embryonic development. Specifically, we found that the piRNA amplification loop was repressed by miR-17-5p, leading to increased levels of transposition mutagenesis. This occurred by suppressing the amplification loop of piRNAs with an identical 5' sequence and by targeting Mili/Miwi2, an essential component of the piRNA amplification loop, and the DNA methyltransferase, Dnmt3a. We also found that increased levels of piRNAs could compete with miRNAs for target binding, resulting in increased expression of Dnmt3a and Mili. Increased Dnmt3a levels could in turn block miR-17-5p expression, while increased Mili expression could accelerate piRNA amplification and inhibit transposon generation, favoring embryonic development. We report for the first time the reciprocal regulation between miRNAs and piRNAs in mouse embryonic development.

Fixed-dose Pegfilgrastim is Safe and Allows Neutrophil Recovery in Patients with Non-Hodgkin's Lymphoma

Twenty-nine patients with non-Hodgkin's lymphoma received a single subcutaneous injection of 6 mg pegfilgrastim approximately 24 h after the start of CHOP chemotherapy. The safety of pegfilgrastim in this patient population was determined by reports of adverse events. The pharmacokinetics of pegfilgrastim were characterized and the duration of grade 4 neutropenia, time to absolute neutrophil count (ANC) recovery to > or = 2.0 x 10(9)/l, neutrophil nadir, and incidence of febrile neutropenia were determined in the first 21-day chemotherapy cycle. The incidence of grade 4 neutropenia in cycle 1 was 43% with a mean (SD) duration of grade 4 neutropenia value of 1.0 (1.4) day. No apparent relationship between the duration of grade 4 neutropenia and body weight was observed. The median [quartiles] time to ANC recovery was 10 [9, 11] days. The incidence of febrile neutropenia was 11%. No unexpected adverse events were reported and no patient developed antibodies to pegfilgrastim. Serum concentration of pegfilgrastim reached a maximum (median [quartiles]) of 128 [58, 159] ng/ml at approximately 24 h after administration, and was followed by a second smaller peak (median [quartiles]) of 10.6 [3.0, 20.5] ng/ml at the time of the neutrophil nadir. After the second peak, concentration of pegfilgrastim declined linearly with a median terminal half-life of approximately 42 h.

MicroRNA miR-93 promotes tumor growth and angiogenesis by targeting integrin-β8

It has been reported that the miR-106b∼25 cluster, a paralog of the miR-17∼92 cluster, possesses oncogenic activities. However, the precise role of each microRNA (miRNA) in the miR-106b∼25 cluster is not yet known. In this study, we examined the function of miR-93, one of the microRNAs within the miR-106b∼25 cluster, in angiogenesis and tumor formation. We found that miR-93 enhanced cell survival, promoted sphere formation and augmented tumor growth. Most strikingly, when miR-93-overexpressing U87 cells were co-cultured with endothelial cells, they supported endothelial cell spreading, growth, migration and tube formation. In vivo studies revealed that miR-93-expressing cells induced blood vessel formation, allowing blood vessels to extend to tumor tissues in high densities. Angiogenesis promoted by miR-93 in return facilitated cell survival, resulting in enhanced tumor growth. We further showed that integrin-β8 is a target of miR-93. Higher levels of integrin-β8 are associated with cell death in tumor mass and in human glioblastoma. Silencing of integrin-β8 expression using small interfering RNA promoted cell proliferation, whereas ectopic expression of integrin-β8 decreased cell growth. These findings showed that miR-93 promotes tumor growth and angiogenesis by suppressing, at least in part, integrin-β8 expression. Our results suggest that inhibition of miR-93 function may be a feasible approach to suppress angiogenesis and tumor growth.

Malignant triton tumour of the parapharyngeal space: a case arising from the cervical sympathetic nerve

BACKGROUND

Malignant triton tumour is a relatively rare, aggressive sarcoma comprising both malignant schwannoma cells and malignant rhabdomyoblasts. Malignant triton tumour of the parapharyngeal space is exceptionally rare, with only one case being described in the literature. Malignant triton tumour of the cervical sympathetic nerve has not previously been reported.

METHODS

We report a case involving the parapharyngeal space and arising from the cervical sympathetic nerve, and we review the management and outcome of the previous case reported in this rare location.

CONCLUSIONS

The parapharyngeal space is a unique location. Owing to this specific localisation, adjuvant therapy in addition to complete resection may be important in the treatment of malignant triton tumour in this rare location.

Pegfilgrastim, a sustained-duration form of filgrastim, significantly improves neutrophil recovery after autologous marrow transplantation in rhesus macaques

Daily administration of filgrastim decreases the duration of severe neutropenia in the clinical setting. A sustained-duration form of filgrastim, pegfilgrastim, significantly reduces scheduling protocols to a single injection per chemotherapy cycle while maintaining therapeutic efficiency. We examined the ability of a single injection of pegfilgrastim to significantly improve neutrophil recovery following autologous bone marrow transplantation (AuBMT) in rhesus macaques. On day 1, postmyeloablation (920 cGy x-irradiation) and AuBMT, animals received either 0.1% autologous serum for 18 consecutive days (n=13), or single doses of pegfilgrastim via the subcutaneous (s.c.) or intravenous (i.v.) route (300 or 100 micro g/kg), or a single dose of filgrastim at 300 micro g/kg via the s.c. or i.v. route, or filgrastim at 10 micro g/kg via the s.c. route (n=4) on a daily basis (range=days 12-17). Pharmacokinetic parameters and neutrophil recovery were assessed. A single dose of pegfilgrastim via the i.v. or s.c. route was as effective as daily filgrastim administration, resulting in significant improvement of neutrophil recovery after myeloablation and ABuMT. Effective pegfilgrastim plasma concentrations were maintained in neutropenic animals until after the onset of hematopoietic recovery. Enhanced pharmacokinetics in AuBMT cohorts are consistent with self-regulating, neutrophil-mediated clearance.

Comparable efficacy and safety profiles of once-per-cycle pegfilgrastim and daily injection filgrastim in chemotherapy-induced neutropenia: a multicenter dose-finding study in women with breast cancer

BACKGROUND

Neutropenia is common in patients receiving myelotoxic chemotherapy. Pegfilgrastim, a sustained-duration filgrastim is a once-per-cycle therapy for prophylactic neutrophil support.

PATIENTS AND METHODS

Women, treated with four cycles of doxorubicin/docetaxel chemotherapy every 21 days, received pegfilgrastim or filgrastim 24 h after chemotherapy as a single subcutaneous injection per chemotherapy cycle (pegfilgrastim 30, 60 or 100 microg/kg) or daily subcutaneous injections (filgrastim 5 microg/kg/day). Safety, efficacy and pharmacokinetics were analyzed.

RESULTS

The incidence of grade 4 neutropenia in cycle 1 was 95, 90 and 74%, in patients who received pegfilgrastim 30, 60 and 100 microg/kg, respectively, and 76% in patients who received filgrastim. Mean duration of grade 4 neutropenia in cycle 1 was 2.7,2 and 1.3 days for doses of pegfilgrastim, and 1.6 days for filgrastim. The pharmacokinetics of pegfilgrastim were non-linear and dependent on both dose and neutrophil count. Pegfilgrastim serum concentration was sustained until the neutrophil nadir occurred then declined rapidly as neutrophils started to recover, consistent with a self-regulating neutrophil-mediated clearance mechanism. The safety profiles of pegfilgrastim and filgrastim were similar.

CONCLUSIONS

A single subcutaneous injection of pegfilgrastim 100 microg/kg provided neutrophil support and a safety profile comparable to daily subcutaneous injections of filgrastim during multiple chemotherapy cycles.

Identification of the motif in versican G3 domain that plays a dominant-negative effect on astrocytoma cell proliferation through inhibiting versican secretion and binding

This study was designed to investigate the mechanisms by which mutant versican constructs play a dominant-negative effect on astrocytoma cell proliferation. Although a mini-versican or a versican G3 construct promoted growth of U87 astrocytoma cells, a mini-versican lacking epidermal growth factor (EGF) motifs (versicanDeltaEGF) and a G3 mutant (G3DeltaEGF) exerted a dominant-negative effect on cell proliferation. G3DeltaEGF-transfected cells formed smaller colonies, arrested cell cycle at G(1) phase, inhibited expression of cell cycle proteins cdk4 and cyclin D1, and contained multiple nucleoli. In cell surface binding assays, G3 products expressed in COS-7 cells and bacteria bound to U87 cell surface. G3DeltaEGF products exhibited decreased binding activity, but higher levels of G3DeltaEGF products were able to inhibit the binding of G3 to the cell surface. G3DeltaEGF expression inhibited secretion of endogenous versican in astrocytoma cells and also inhibited the secretion of mini-versican in COS-7 cells co-transfected with the mini-versican and G3DeltaEGF constructs. The effect seems to depend on the expression efficiency of G3DeltaEGF, and it occurred via the carbohydrate recognition domain.

Roles of aggrecan domains in biosynthesis, modification by glycosaminoglycans and product secretion

Aggrecan is a member of the chondroitin sulphate (CS) proteoglycan family, which also includes versican/PG-M, neurocan and brevican. Members of this family exhibit structural similarity: a G1 domain at the N-terminus and a G3 domain at the C-terminus, with a central sequence for modification by CS chains. A unique feature of aggrecan is the insertion of three additional domains, an inter-globular domain (IGD), a G2 domain and a keratan sulphate (KS) domain (sequence modified by KS chains), between the G1 domain and the CS domain (sequence modified by CS chains). The G1 and G3 domains have been implicated in product secretion, but G2, although structurally similar to the tandem repeats of G1, performs an unknown function. To define the functions of each aggrecan domain in product processing, we cloned and expressed these domains in various combinations in COS-7 cells. The results indicated that the G3 domain enhanced product secretion, alone or in combination with the KS or CS domain, and promoted glycosaminoglycan (GAG) chain attachment. Constructs containing the G1 domain were not secreted. Addition of a CS domain sequence to G1 reduced this inhibition, but GAG chain attachment was still decreased. The potential GAG chain attachment site in the IGD was occupied by GAGs, and IGD product was secreted efficiently. The KS domain was modified by GAG chains and secreted. Finally, the G2 domain was expressed but not secreted, and inhibited secretion of the IGD when expressed as an IGD-G2 combination.

Versican modulates embryonic chondrocyte morphology via the epidermal growth factor-like motifs in G3

This investigation was designed to characterize the effect of the extracellular matrix molecule versican on chondrocyte morphology, using the well-studied chondrocyte cell culture system. When cultured chondrocytes reverted or "dedifferentiated" to a fibroblast-like morphology, we found that versican expression was significantly enhanced. Transfection of chondrocytes, isolated from embryonic chicken sterna, with a chicken miniversican construct accelerated the reversion process, while expression of an antisense construct inhibited it. A mutant miniversican lacking two epidermal growth factor-like motifs (versicanDeltaEGF) promoted differentiation, as shown by morphological changes and changes in the expression of other extracellular matrix molecules. A truncated versican mutant, the G3DeltaEGF, a G3 domain lacking its two epidermal growth factor-like motifs, also enhanced differentiation. This effect is related to G3DeltaEGF-induced change in cytoskeleton, since transfected cells exhibited misassembly of actin filaments. This article thus provides the first evidence that versican modulates chondrocyte morphology via changes in cytoskeletal structure, and may imply that extracellular matrix molecules play an important role in cell differentiation.

Epidermal growth factor induces cell cycle arrest and apoptosis of squamous carcinoma cells through reduction of cell adhesion

Most squamous epithelial cells are strictly anchorage-dependent cell types. We observed that epidermal growth factor (EGF) promoted the growth of A431 squamous carcinoma cells in suspension cultures but suppressed cell growth and induced apoptosis in monolayer cultures, suggesting that loss of adhesion is responsible for the effects observed in monolayer culture, before cell death. Consistent with this finding, we demonstrated that EGF reduced cell attachment, cell-cell interaction, and cell spreading. Treatment with EGF increased cell adhesion-regulated expression of p21 but suppressed expressions of cyclin A, D1, cdk2, and retinoblastoma protein (pRb), leading to cell cycle arrest and adhesion-regulated programmed cell death. To test directly whether promoting cell adhesion could reduce the effects of EGF, we grew cultures on plates coated with type II collagen. On these plates, cell adhesion was enhanced and EGF treatment had little effect on cell adhesion and apoptosis when cells were attached to the collagen. The collagen effects were dose dependent, and cell cycle and cell cycle-associated proteins were altered accordingly. Finally, when cultures were plated on bacterial Petri dishes, which completely disrupted cell attachment to substratum, the level of apoptosis was greatly higher and cell cycle was arrested as compared with monolayer cultures. Taken together, our results strongly suggest that the EGF-induced cell cycle arrest and apoptosis in monolayer cultures was the result of a decline in cell adhesion.

The roles of matrix molecules in mediating chondrocyte aggregation, attachment, and spreading

The most abundant macromolecules in cartilage are hyaluronan, collagen, aggrecan, and link protein, which are believed to play roles in maintaining a unique three-dimensional network for a functional joint. This study was designed to investigate the roles of the major extracellular molecules in mediating chondrocyte-matrix interactions. We employed specific approaches to remove components individually or in combination: hyaluronan was digested with hyaluronidase; type II collagen was digested with collagenase; aggrecan expression was inhibited with antisense and beta-xyloside approaches; and link protein expression was inhibited with antisense oligonucleotides. Digestion of hyaluronan induced chondrocyte attachment to tissue culture plates, collagen-coated plates, and fibroblast-like chondrocyte cultures, and induced chondrocyte aggregation. Treated chondrocytes exhibited a fibroblast-like morphology, and the effects of hyaluronidase were dose-dependent. Conversely, the effect of collagenase on chondrocyte adhesion and aggregation was far less pronounced. Treatment with Arg-Gly-Asp peptide inhibited chondrocyte-collagen interaction. Chondrocyte attachment was enhanced by antisense oligonucleotides complementary to aggrecan and link protein and by beta-xyloside treatment. Nevertheless, hyaluronan seems to predominate over the other molecules in mediating chondrocyte-matrix interactions.

Tandem repeats are involved in G1 domain inhibition of versican expression and secretion and the G3 domain enhances glycosaminoglycan modification and product secretion via the complement-binding protein-like motif

The large aggregating chondroitin sulfate proteoglycans, including aggrecan, versican (PG-M), neurocan, and brevican, are characterized by N-terminal and C-terminal globular (or selectin-like) domains known as the G1 and G3 domains, respectively. For this study, we generated a series of expression constructs containing various combinations of chicken versican/PG-M domains and a leading peptide of link protein in order to examine the roles of the G1 and G3 domains in versican function. In transfection studies, we observed that the presence of the G1 domain was sufficient to inhibit product secretion, while the G3 domain enhanced this process. We also demonstrated that the G1 domain inhibited the attachment of glycosaminoglycan chains to the core proteins, while the G3 domain enhanced this process. Further studies revealed that inhibition of secretion by G1 was mediated by its two tandem repeats, while G3's promotion of glycosaminoglycan chain attachment was apparently dependent on G3's complement-binding protein (CBP)-like motif. The modulatory effects of these two molecular domains may contribute to versican's biological activities.

Randomized, dose-escalation study of SD/01 compared with daily filgrastim in patients receiving chemotherapy

PURPOSE

To explore the use of SD/01 (a polyethylene glycol-conjugated filgrastim shown in preclinical studies to have a prolonged half-life) in patients with chemotherapy-induced neutropenia.

PATIENTS AND METHODS

Thirteen patients with non-small-cell lung cancer were randomized to receive daily filgrastim (5 microg/kg/d) or a single injection of SD/01 (30, 100, or 300 microg/kg) 2 weeks before chemotherapy and again 24 hours after administration of carboplatin and paclitaxel. Pharmacodynamic, pharmacokinetic, and safety analyses were performed.

RESULTS

Peak serum concentrations of SD/01 and the duration of increased serum concentrations were dependent on the SD/01 dose. SD/01 concentrations remained increased longer in patients with chemotherapy-induced neutropenia. Prechemotherapy median absolute neutrophil counts (ANCs) in patients receiving SD/01 were increased in a dose-dependent fashion, with the duration of this effect also being dose dependent. After chemotherapy, median ANC nadirs were similar in the filgrastim cohort and the cohort receiving SD/01 30 microg/kg, with higher nadirs seen in the cohorts receiving SD/01 100 or 300 microg/kg. Dose-limiting toxicities were not noted. CD34(+) cells were mobilized in all cohorts.

CONCLUSION

A single dose of SD/01 increases the serum concentration of SD/01 for several days in a dose-dependent fashion and is not associated with significant toxicity. The effects of SD/01 on ANC and CD34(+) cell mobilization are comparable or greater than those achieved with daily filgrastim. The self-regulation of this molecule provides a potential therapeutic advantage in a variety of clinical settings associated with neutropenia.

Pharmacodynamics and pharmacokinetic-pharmacodynamic relationships of atorvastatin, an HMG-CoA reductase inhibitor

The objective of this study is to determine the relationships between plasma atorvastatin concentrations, LDL (low-density lipoprotein) cholesterol reduction, and atorvastatin dose; the earliest time at which lipid levels change when atorvastatin treatment is initiated or discontinued; and alterations in LDL particle composition. Twenty-four subjects with elevated LDL-cholesterol were treated with escalating daily doses of 5, 20, and 80 mg atorvastatin for 6 weeks each. Serial plasma lipid and lipoprotein analyses were performed during the initiation and discontinuation of atorvastatin therapy, as well as at steady state. LDL-apolipoprotein B and LDL-cholesterol were measured directly after ultracentrifugation, and LDL-cholesterol also was estimated by the method of Friedewald. Steady-state atorvastatin pharmacokinetic parameters were estimated on the last day of each dosing period. LDL-cholesterol (Friedewald) reductions of 34%, 43%, and 57% were produced by atorvastatin doses of 5, 20, and 80 mg, respectively. The mean dose-response relationship was log linear, and almost all individual dose-response curves paralleled the mean curve. LDL-apolipoprotein B reductions were slightly less than those of LDL-cholesterol. Atorvastatin area under the curve (AUC(0-24) values increased proportionally with dose, while values of Cmax (maximum concentration) increased more than proportionally, and Cmin (minimum concentration) increased less than proportionally. Following initiation of dosing, statistically significant decreases in total cholesterol, LDL-cholesterol (beta quant), and LDL-apolipoprotein B were observed within 24 hours and in LDL-C (Friedewald) within 72 hours. Following discontinuation of drug dosing, statistically significant increases were observed in total cholesterol and LDL-cholesterol (Friedewald) within 48 hours and in LDL-cholesterol (beta quant) and LDL-apolipoprotein B within 72 hours. At each dose, an individual's LDL-cholesterol response was not correlated with AUC(0-24). In conclusion, atorvastatin produces marked LDL-cholesterol reductions, the mean dose-response relationship is log linear, almost all individual dose-response curves parallel the mean dose-response curve, onset and cessation of action are rapid, the estimated and measured LDL-cholesterol are the same, LDL-cholesterol and LDL-Apo B reductions are similar, and plasma concentrations are not correlated with LDL-cholesterol reduction at a given dose.

beta-Integrin-collagen interaction reduces chondrocyte apoptosis

We have observed that the spent culture media in suspended chondrocyte cultures is essential for the survival of the cells, since complete change of the spent media induces severe programmed cell death (apoptosis). Moreover, we showed that extracellular matrix (ECM) molecules in the culture media provide vital chondrocyte-matrix interactions; when media are changed, cells are deprived of matrix molecules and undergo apoptosis. In this paper we report that interaction with collagen, a ubiquitous extracellular matrix molecule, is essential for chondrocyte survival. Such an interaction causes chondrocyte aggregation and reduces the level of chondrocyte apoptosis. Hyaluronan, an abundant ECM molecule, can influence the effects of collagen by preventing chondrocyte aggregation. Degradation of hyaluronan with hyaluronidase results in chondrocyte aggregation, and this reduces the level of chondrocyte apoptosis. Experiments with an antibody to integrin beta1 suggest that the collagen-chondrocyte interactions are mediated through integrin beta1, and these interactions may protect chondrocytes from apoptosis. We hypothesize that hyaluronan binds aggrecan and link protein, forming stable ternary complexes, which interact with the chondrocyte surface, perhaps via CD44, and thus maintains a stable chondrocyte-matrix network.

Promotion of chondrocyte proliferation by versican mediated by G1 domain and EGF-like motifs

We have previously demonstrated that versican stimulated NIH3T3 fibroblast proliferation. Since versican is expressed in cartilage, we investigated whether versican plays a role in chondrocyte proliferation. We developed a technique to stably express a recombinant versican mini-gene in chicken chondrocytes, and its effect on chondrocyte proliferation was analyzed by the increase in cell number. The effect of cell adhesion on cell proliferation was tested. Finally, the versican mini-gene was truncated to assess the role of EGF-like motifs in cell proliferation. Expression of the recombinant versican mini-gene stimulated chondrocyte proliferation. Antisense oligonucleotides complementary to versican inhibited chondrocyte proliferation. The G1 domain of versican stimulated chondrocyte proliferation by destabilizing chondrocyte adhesion. Furthermore, deletion of the two EGF-like motifs from the G3 domain also reduced the function of versican in stimulating cell proliferation. Versican enhances chondrocyte proliferation through a mechanism involving its G1 and G3 domains. This finding may have implications for our understanding of the pathogenesis of various joint diseases.

Versican enhances locomotion of astrocytoma cells and reduces cell adhesion through its G1 domain

Versican is a large extracellular proteoglycan and is expressed in a variety of tissues including the central nervous system. A malignant astrocytoma cell line U87 with high motility expressed a higher level of versican than another malignant astrocytoma cell line U343 with lower motility. We observed that the U87 cells were less adherent to tissue culture plates than the U343 cells. To investigate the role of versican in astrocytoma cell migration, we generated recombinant products of a mini-versican construct expressed in COS-7 cells. We found that the mini-versican products enhanced astrocytoma cell migration. Furthermore, enhanced migration was promoted by the G1 domain but not the G3 domain of versican. We introduced culture medium containing products of the mini-versican, the G1, and the G3 constructs separately into the astrocytoma cell lines U87 and U343. The mini-versican and the G1 construct, but not the G3 construct, were shown to reduce astrocytoma cell adhesion. The present data suggest that versican exerts its effect on astrocytoma cell migration and adhesion through the G1 domain.

Erythromycin coadministration increases plasma atorvastatin concentrations

The effect of erythromycin on the pharmacokinetics of atorvastatin, an inhibitor of HMG-CoA reductase, was investigated in 12 healthy volunteers. Each subject received a single 10 mg dose of atorvastatin on two separate occasions, separated by 2 weeks. Erythromycin (500 mg qid) was given from 7 days before through 4 days after the second atorvastatin dose. Atorvastatin concentrations were determined by an enzyme inhibition assay, which measured both atorvastatin and active metabolites. When erythromycin was coadministered with atorvastatin, mean Cmax and AUC(0-infinity) increased by 37.7% and 32.5%, respectively. Mean terminal half-life was similar following each atorvastatin dose. Possible mechanisms for this interaction include erythromycin inhibition of first-pass conversion of atorvastatin to inactive metabolites and erythromycin inhibition of P-glycoprotein-mediated intestinal or biliary secretion.

Cell adhesion and proliferation mediated through the G1 domain of versican

We have demonstrated previously that versican stimulated cell proliferation through the G3 domain. In these experiments, we show that versican mini-gene-transfected cell lines exhibited decreased cell-substratum interaction and increased cell proliferation. Exogenous addition of growth medium containing the versican gene product produced the same results. Because the G1 domain of versican is structurally similar to the G1 domain of aggrecan and to link protein, both of which play role in cell adhesion, we hypothesized that versican's proliferative effects may be a consequence of its ability to reduce cell adhesion, and may be mediated through the G1 domain. To investigate this, we expressed a G1 construct in NIH3T3 cells and showed that it reduced cell adhesion and enhanced cell proliferation. We then demonstrated that deletion of the G1 domain from versican greatly, but not completely, reversed the effects of versican: G1-deletion mutants of versican show slightly reduced amounts of cell adhesion and slightly increased rates of proliferation. We concluded that versican can stimulate cell proliferation via two mechanisms: through two EGF-like motifs in the G3 domain which play a role in stimulating cell growth, and through the G1 domain, which destabilizes cell adhesion and facilitates cell growth. We purified the G1 product with an affinity column and demonstrated that it reduced cell adhesion and enhanced cell proliferation.

Chondrocyte apoptosis induced by aggrecan G1 domain as a result of decreased cell adhesion

A major feature of cartilage deterioration during joint injury and disease is aggrecan degradation and the loss of proteoglycan. Most of the degraded fragments are released into the circulatory system except the G1 domain which accumulates locally in the synovial fluid and cartilage because of its hyaluronan-binding ability. In this study, our objective was to investigate the effects of G1 accumulation on chondrocyte function. We chose to mimic the accumulation of G1 domain by developing a method to express G1 in chondrocytes. We transiently and stably expressed aggrecan G1 domain in the cells and tested the effects of G1 in cell adhesion and apoptosis. Overexpression of the G1 construct induced apoptosis in adherent chondrocytes but not in chondrocytes maintained in suspension cultures. Higher levels of G1 expression caused greater reduction in cell-substratum interaction and induced more cell death. The effect was dose dependent. To corroborate our findings, the role of G1 in reducing adhesion and inducing apoptosis was further investigated in fibroblasts. We found that low adherent cultures also had high levels of apoptosis. Our results suggest that G1 induced apoptosis by destabilizing cell-substratum interaction.

The G3 domain of versican inhibits mesenchymal chondrogenesis via the epidermal growth factor-like motifs

Versican is a highly expressed proteoglycan in zones of developing tissues. To investigate whether versican plays a role in cell differentiation, we studied its role in mesenchymal condensation and chondrogenesis. Here we report that a mini-versican gene product inhibits mesenchymal chondrogenesis but not condensation. The mini-versican-treated mesenchymal cultures form fewer, smaller cartilaginous nodules and produced lower levels of link protein and type II collagen. The versican G3 domain alone, but not G1, was sufficient to inhibit mesenchymal chondrogenesis. Deletion of two epidermal growth factor (EGF)-like motifs in the G3 domain abolished the effect of versican. The G3 domain of aggrecan, which does not contain an EGF-like motif, did not inhibit mesenchymal chondrogenesis. We also generated a chimera construct containing the two EGF-like motifs of versican and the G3 domain of aggrecan, and we observed that this chimera construct inhibited chondrogenesis to a lesser extent than did the full-length versican G3 construct. Direct transfection of mesenchymal cells with different constructs produced similar results. Furthermore, treatment with versican antisense oligonucleotides and transfection with a versican antisense construct promoted chondrogenesis. Taken together, our results strongly suggest that versican inhibits mesenchymal chondrogenesis via its EGF-like motifs.

Expression of the G1 domain of aggrecan interferes with chondrocyte attachment and adhesion

The proteoglycan aggrecan is a major component of cartilage, and degradation of aggrecan is associated with aging and a number of pathological conditions. To investigate the effects of the accumulation of G1 domain from degraded aggrecan, we overexpressed the G1 domain in cell culture. Exogenous addition of the expressed G1 gene product to chondrocyte cultures retarded the attachment of chondrocytes to tissue culture plates, type II collagen and hyaluronan. Expression of the G1 construct, aggrecan or link protein in chondrocytes led to decreased cell adhesion. Interestingly, aggrecan (and specifically G1) and link protein, when applied simultaneously, seem to be able to interact and inhibit the destabilization of chondrocyte adhesion observed when either is applied alone. The G3 domain of aggrecan has little effect on chondrocyte adhesion and did not change the effects of link protein and the G1 domain on chondrocyte adhesion. These effects probably involve the binding of G1 to cell surface molecules, since FACS (fluorescence-activated cell sorter) analysis demonstrated that the G1 domain binds to the chondrocyte surface with high affinity.

Cupric nitrilotriacetate induces oxidative DNA damage and apoptosis in human leukemia HL-60 cells

Recent reports have implicated a possible role of reactive oxygen species (ROS) in the induction and mediation of apoptosis and DNA damage. Oxidative DNA base modification induced by cupric nitrilotriacetate (Cu-NTA) and the following apoptosis were observed in human promyelocytic leukemia HL-60 cells. We measured the level of ROS in the cells by using a fluorescence probe, 2',7'-dichlorofluorescein diacetate (DCFH-DA), and the amount of a modified DNA base, 8-hydroxydeoxyguanosine (8-OHdG) by HPLC-ECD. It was found that Cu-NTA exposure significantly enhanced ROS and 8-OHdG formation in the cells. Meanwhile, we observed both DNA fragmentation and morphological changes characteristic of apoptosis, which was also determined quantitatively by flow cytometry and showed dose- and time-dependent manners. Furthermore, several antioxidants such as dimethyl sulfoxide (DMSO), superoxide dismutase (SOD), and catalase were used to detect whether the apoptosis could be blocked. Only DMSO protected against this form of cell death. To elucidate molecular events in the apoptosis, expressions of Bcl-2 protein family members, such as Bcl-2, Bcl-X and Bax, and heat shock protein 70 (HSP-70) were measured by western blotting using specific antibodies. The levels of Bax and Bcl-Xs remained largely unchanged, but the Bcl-2 and Bcl-XL expression showed down-regulation. After 24 h incubation in the presence of copper, the levels of Bcl-2 and Bcl-XL reduced about 33.8% and 51.1% compared with untreated cells, respectively. Furthermore, after 16 h incubation, the level of HSP-70 expression was about 3.4-fold greater than that in untreated cells, suggesting that HSP-70 is important in increasing resistance to oxidative stress induced by Cu-NTA. But overexpression of HSP-70 failed to protect HL-60 cells from apoptosis induced by Cu-NTA. We inferred that Cu-NTA may induce oxidative DNA damage through free radical injuries, which may turn on the apoptosis in HL-60 cells.

The G3 domain of versican enhances cell proliferation via epidermial growth factor-like motifs

Versican is a member of the large aggregating chondroitin sulfate proteoglycan family. We have expressed in NIH3T3 fibroblasts a recombinant versican mini-gene comprising the G1 and G3 domains and 15% of the CS domain. We observed that expression of the mini-versican gene stimulated cell proliferation as determined by cell counting and cell cycle analysis. Addition of exogenous mini-versican protein to cultured cells produced the same result. The effects of the mini-versican were greatly reduced when the G3 domain was deleted. Expression of the G3 domain alone promotes cell proliferation, and addition of purified G3 gene products to NIH3T3 fibroblasts and cultured chicken fibroblasts enhances cell growth. Further, deletion of the epidermal growth factor (EGF)-like motifs in the versican G3 domain reduced the effects of the mini-versican on cell proliferation. In the presence of the purified mini-versican protein, antisense oligonucleotides to the EGF receptor inhibited proliferation of NIH3T3 fibroblasts, compared with control sense oligonucleotides. Taken together, these results imply that versican enhances cell proliferation, and this effect is mediated, at least in part, by the action of versican EGF-like motifs on endogenous EGF receptor.

Aggrecan and link protein affect cell adhesion to culture plates and to type II collagen

Cartilage is a hypocellular tissue in which a balance of matrix molecules, especially aggrecan and link protein, play a critical role in maintaining structural integrity. To study the role of aggrecan and link protein in mediating cell activities, we have stably expressed them in NIH/3T3 fibroblasts and observed the effect on cell-substratum interactions. Overexpression of either protein destabilized the cell-substratum interaction. However, when both were co-expressed, the interaction between cell and substratum was less impaired. Similar results were obtained on type II collagen-coated plates. The addition of exogenous gene products into fibroblast cell lines and chondrocyte culture had the same effect as expression of the genes. The addition of exogenous hyaluronan to the growth medium or treatment of cells with hyaluronidase also decreased cell adhesion, indicating that hyaluronan also plays a role in the cell-substratum adhesion. The presence of aggrecan seems to increase the amount of link protein on the cell surface. Chondrocytes expressing high concentrations of aggrecan and link protein were maintained within a matrix network and were able to survive in suspended culture. Imbalances in aggrecan or link protein concentrations, or degradation of hyaluronan, disrupted the network and caused the chondrocytes to aggregate or adhere to the plates.

Renal dysfunction does not alter the pharmacokinetics or LDL-cholesterol reduction of atorvastatin

The objective of this study was to determine the effects of renal dysfunction on the steady-state pharmacokinetics and pharmacodynamics of atorvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor. Nineteen subjects with calculated creatinine clearances ranging from 13 mL/min to 143 mL/min were administered 10 mg atorvastatin daily for 2 weeks. Pharmacokinetic parameters and lipid responses were analyzed by regression on calculated creatinine clearance. Correlations between steady-state atorvastatin pharmacokinetic or pharmacodynamic parameters and creatinine clearance were weak and, in general, did not achieve statistical significance. Although the elimination rate constant, lambda z (0.579), was significantly correlated with creatinine clearance, neither maximum plasma concentration (Cmax, -0.361) nor oral clearance (Cl/F, 0.306) were; thus, steady-state exposure is not altered. Renal impairment has no significant effect on pharmacodynamics and pharmacokinetics of atorvastatin.

Pharmacokinetics of a 7-day 17 beta-estradiol transdermal delivery system: effect of application site and repeated applications on serum concentrations of estradiol and estrone

FemPatch (Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, MI), a new 7-day 17 beta-estradiol transdermal delivery system (TDS), has been developed for treatment of menopausal vasomotor symptoms. This two-period crossover study was conducted to determine the effects of TDS application site (buttocks versus abdomen) and early TDS replacement on estradiol and estrone concentrations, and to quantify intersubject and intrasubject pharmacokinetic variability. Eighteen healthy, postmenopausal female volunteers received a single 7-day TDS application to the abdomen and repeated TDS applications to the buttocks (regular replacement on days 7 and 14, intentional early replacement on day 17, and removal on day 21). Serial serum samples were assayed for estradiol and estrone by validated radioimmunoassay methods. The 7-day TDS delivers estradiol at a constant, near zero-order rate for the duration of application, independent of application site. Mean serum estradiol concentrations were higher after application to the buttocks than after application to the abdomen (19 and 15 pg/mL above baseline, respectively), making the buttocks the preferred site for TDS application. Mean serum concentration of estradiol was slightly higher (23 pg/mL above baseline) for the treatment week with early TDS replacement due to the transient increase in concentration over the first 24 hours after replacement. Parallel but smaller increases in concentrations of estrone were observed. Serum estradiol and estrone concentrations are reproducible within an individual from application to application (coefficient of variation, 25%). Variability between individuals was higher (coefficient of variation, 40-50%).

Pharmacokinetic and pharmacodynamic comparisons of twice daily and four times daily formulations of procainamide in patients with frequent ventricular premature depolarization

A study was conducted to evaluate the pharmacokinetics of procainamide and its active metabolite, N-acetylprocainamide (NAPA), as a function of dose and formulation and to characterize the relationship between ventricular premature depolarization (VPD) rate and plasma concentrations of procainamide and NAPA. A subset of patients (n = 43) with frequent VPD who were enrolled in a double-blind, multicenter, activity trial were assigned in randomized fashion to receive 1 of 4 dose levels (placebo or 1,000, 2,000, or 4,000 mg/day procainamide) and to receive Procanbid (Parke-Davis) tablets every 12 hours or Procan SR (Parke-Davis) tablets every 6 hours during the first week of a blinded crossover phase. Patients crossed over to the alternative formulation after one week. Maximum and steady-state average concentrations of procainamide and NAPA after administration of Procanbid tablets were equivalent to those after administration of an equivalent daily dose of Procan SR tablets. Corresponding trough concentrations of procainamide were lower after administration of Procanbid tablets than after administration of Procan SR tablets. Both formulations produced disproportionate increases in procainamide concentrations with increasing dose; concentrations of NAPA increased in proportion to dose. Assessment of the relationship between VPD rate and drug concentration in plasma indicated no substantive difference between the two formulations. It was concluded that administration of Procanbid tablets every 12 hours is essentially equivalent to administration of procainamide extended-release tablets (Procan SR) every 6 hours with respect to pharmacokinetics of procainamide and NAPA and to VPD suppression.

Effects of atorvastatin, an HMG-CoA reductase inhibitor, on hepatic oxidative metabolism of antipyrine

Possible effects of multiple-dose administration of atorvastatin on the pharmacokinetics of single-dose antipyrine were evaluated in this drug-drug interaction study. Twelve healthy male volunteers received three 200-mg capsules of antipyrine on days 1 and 22, and two 40-mg atorvastatin tablets in the morning on days 8 through 23. Serial blood and urine samples were collected after administration of each antipyrine dose. Plasma was analyzed for antipyrine, and urine samples were analyzed for antipyrine, 4-hydroxyantipyrine, and norantipyrine by validated high-performance liquid chromatography with ultraviolet detection. Overall, antipyrine and atorvastatin doses were well tolerated in healthy volunteers. Mean antipyrine concentrations in plasma after administration of a single, oral dose of antipyrine during coadministration of multiple doses of atorvastatin were nearly superimposible on concentrations after administration of antipyrine alone. Individual and mean parameter values for plasma pharmacokinetics of antipyrine were similar in both treatment periods. Atorvastatin did not significantly alter the fraction of clearance of antipyrine in plasma that occurred by urinary excretion of 4-hydroxyantipyrine and norantipyrine. These results indicate that the recommended highest daily dose of atorvastatin has negligible effects on antipyrine pharmacokinetics and on oxidative pathways responsible for the metabolism of antipyrine.