Drug properties of second-generation antisense oligonucleotides: how do they measure up to their predecessors?

Antisense technology has progressed beyond the point of using only phosphorothioate oligodeoxynucleotides as therapeutic agents to looking at antisense molecules that contain additional chemical modifications as the next generation of therapeutic agents. These modifications are intended to improve the overall therapeutic properties by increasing potency, optimizing pharmacokinetic properties and improving the safety profile. This review will focus on the non-clinical pharmacokinetic and safety properties of 2'-O-methoxyethyl-modified oligonucleotides. Implications on the convenience and safe use of these compounds as therapeutic agents will be discussed.

Polymorphisms of 5,10-methylenetetrahydrofolate reductase and risk of gastric cancer in a Chinese population: a case-control study

Low dietary folate intake has been associated with increased risk of gastric cancer. The 5,10-methylenetetrahydrofolate reductase (MTHFR) involved in folate metabolism has 2 variants, C677T and A1298C, that result in decreased MTHFR activity and lower plasma folate levels. Therefore, we hypothesized that these 2 variants play a role in gastric carcinogenesis. We tested this hypothesis in a Chinese population-based case-control study of 187 histopathologically confirmed gastric cancer cases and 166 healthy controls frequency-matched by age (+/-5 years), gender and residential area. The 677TT genotype was associated with increased risk for gastric cancer [adjusted odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.00-3.48] compared to the 677CC genotype. This association was more pronounced for gastric cardia cancer (adjusted OR = 2.47, 95% CI = 1.14-5.32). However, no evidence was found for risk associated with the MTHFR A1298C polymorphism. Our findings support the hypothesis that MTHFR C677T variants contribute to gastric carcinogenesis, particularly in gastric cardia. Larger studies incorporating dietary folate intake and serum levels are needed to confirm our findings.

Polymorphisms of 5,10-methylenetetrahydrofolate reductase and risk of gastric cancer in a Chinese population: a case-control study

Low dietary folate intake has been associated with increased risk of gastric cancer. The 5,10-methylenetetrahydrofolate reductase (MTHFR) involved in folate metabolism has 2 variants, C677T and A1298C, that result in decreased MTHFR activity and lower plasma folate levels. Therefore, we hypothesized that these 2 variants play a role in gastric carcinogenesis. We tested this hypothesis in a Chinese population-based case-control study of 187 histopathologically confirmed gastric cancer cases and 166 healthy controls frequency-matched by age (+/-5 years), gender and residential area. The 677TT genotype was associated with increased risk for gastric cancer [adjusted odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.00-3.48] compared to the 677CC genotype. This association was more pronounced for gastric cardia cancer (adjusted OR = 2.47, 95% CI = 1.14-5.32). However, no evidence was found for risk associated with the MTHFR A1298C polymorphism. Our findings support the hypothesis that MTHFR C677T variants contribute to gastric carcinogenesis, particularly in gastric cardia. Larger studies incorporating dietary folate intake and serum levels are needed to confirm our findings.

Polymorphisms of 5,10-methylenetetrahydrofolate reductase and risk of gastric cancer in a Chinese population: a case-control study

Low dietary folate intake has been associated with increased risk of gastric cancer. The 5,10-methylenetetrahydrofolate reductase (MTHFR) involved in folate metabolism has 2 variants, C677T and A1298C, that result in decreased MTHFR activity and lower plasma folate levels. Therefore, we hypothesized that these 2 variants play a role in gastric carcinogenesis. We tested this hypothesis in a Chinese population-based case-control study of 187 histopathologically confirmed gastric cancer cases and 166 healthy controls frequency-matched by age (+/-5 years), gender and residential area. The 677TT genotype was associated with increased risk for gastric cancer [adjusted odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.00-3.48] compared to the 677CC genotype. This association was more pronounced for gastric cardia cancer (adjusted OR = 2.47, 95% CI = 1.14-5.32). However, no evidence was found for risk associated with the MTHFR A1298C polymorphism. Our findings support the hypothesis that MTHFR C677T variants contribute to gastric carcinogenesis, particularly in gastric cardia. Larger studies incorporating dietary folate intake and serum levels are needed to confirm our findings.

Signal transduction events elicited by cancer prevention compounds

Many chemopreventive agents have been shown to modulate gene expression including induction of phase II detoxifying enzymes, such as glutathione S-transferases (GST) and quinone reductases (QR). Induction of phase II enzymes in general leads to protection of cells/tissues against exogenous and/or endogenous carcinogenic intermediates. The antioxidant or electrophile response element (ARE/EpRE) found at the 5'-flanking region of these phase II genes may play important role in mediating their induction by xenobiotics including chemopreventive agents. Members of the basic leucine zipper (bZIP) transcription factor, Nrf2 which heterodimerizes with Maf G/K, are found to bind to the ARE, and transcriptionally-activated ARE. Recently, we showed that the mitogen-activated protein kinases (MAPK) were activated by phase II gene inducers such as phenolic antioxidant butylated hydroxyanisol (BHA) and isothiocyanate sulforaphane (SUL), and involved in the transcription activation of ARE-mediated reporter gene. Transfection studies with wild-type and dominant negative mutants of Nrf2 and MAPK showed synergistic response during co-transfection as well as to phase II gene inducers. However, increasing the concentrations of these compounds such as BHA, the activities of cell death signaling molecules, caspases, were stimulated and resulted in apoptotic cell death. At these concentrations, BHA stimulated loss of mitochondrial membrane potential, cytochrome c release, and activation of caspase 3, 8 and 9 preceding apoptosis. Further increase in concentrations led to rapid cell necrosis. A model is proposed for BHA and SUL, in that at low concentrations, these potential chemopreventive agents may modulate MAPK pathway leading to transcription activation of Nrf2 and ARE with subsequent induction of cellular defensive enzymes including phase II detoxifying enzymes as well as other defensive genes, which may protect the cells against cellular injury, which is a homeostatic response. At higher concentrations, these agents may activate the caspase pathways, leading to apoptosis, a potential beneficial effect if occurs at preneoplastic/neoplastic tissues, but a potential cytotoxic response if occurs in normal tissues. On the other hand, some phenolic compounds such as resveratrol inhibits TPA- or UV-induced AP-1-mediated activity through the inhibition of c-Src non-receptor tyrosine kinase and MAPK pathways. It is possible that in proliferating or stimulated cells, these chemopreventive compounds may block proliferation by inhibiting these signaling kinases, whereas in non-proliferating or quiescent cells, some of these compounds may activate these signaling kinases leading to gene expression of cellular defensive enzymes such as phase II detoxifying enzymes. The studies of these and other signaling pathways may yield insights into the development of potential chemopreventive compounds.

[Effects of selenium on hepatocellular protooncogene c-myc, c-fos and c-jun expression induced by cadmium in rats]

OBJECTIVES

This study was conducted to explore effects of selenium on hepatocellular protooncogene c-myc, c-fos and c-jun expression induced by cadmium in rats.

METHOD

Both cadmium and selenium were given to rats by i.p. and there were 5 SD rats in each group. Protooncogene c-myc, c-fos and c-jun expression in rat liver cells was measured with Northern Dot Hybridization.

RESULTS

The results showed that cadmium chloride at doses of 5, 10 or 20 mumol/kg, significantly induced proto-oncogene c-myc, c-fos and c-jun expression, and when sodium selenite at the dose of 5 mumol/kg was given at the time, the effect of cadmium chloride on hepatocellular protooncogene c-myc, c-fos and c-jun expression was inhibited.

CONCLUSION

Selenium at certain doses could inhibit hepatocellular protooncogene c-myc, c-fos and c-jun expression induced by cadmium in rats.

Activation of MAPK by TRH requires clathrin-dependent endocytosis and PKC but not receptor interaction with beta-arrestin or receptor endocytosis

To determine whether the interaction of the TRH receptor with beta-arrestin is necessary for TRH activation of MAPK, cells expressing either intact or truncated, internalization-defective TRH receptors were transfected with a beta-arrestin-green fluorescent protein conjugate. In cells expressing the wild-type pituitary TRH receptor, TRH caused translocation of the beta-arrestin-green fluorescent protein conjugate from the cytosol to the plasma membrane within 30 sec. After 5 min, the beta-arrestin-green fluorescent protein conjugate was visible in vesicles, where it colocalized with rhodamine-labeled TRH. In hypertonic sucrose, the beta-arrestin-green fluorescent protein conjugate translocated to the plasma membrane after TRH addition but did not internalize. In cells expressing the truncated TRH receptor, TRH did not cause translocation of the beta-arrestin-green fluorescent protein conjugate. TRH activated MAPK strongly in cells expressing intact or truncated TRH receptors, indicating that the receptor does not need to bind beta-arrestin or internalize. MAPK activation by TRH, epidermal growth factor, and phorbol ester was strongly inhibited by hypertonic sucrose and concanavalin A, which block movement of proteins into coated pits and coated pit assembly. Hypertonic sucrose did not affect MAPK activation in cells overexpressing MAPK kinase 1. Dominant negative dynamin, which blocks conversion of coated pits to vesicles, also reduced receptor internalization and TRH activation of MAPK. TRH activation of MAPK required PKC but was insensitive to pertussis toxin and did not require ras, epidermal growth factor receptor kinase, or PI3K. These results show that the TRH receptor itself does not need to bind beta-arrestin or undergo sequestration to activate MAPK but that the endocytic pathway must be intact.

Induction of xenobiotic enzymes by the MAP kinase pathway and the antioxidant or electrophile response element (ARE/EpRE)

Cellular responses to xenobiotic-induced stress can signal proliferation, differentiation, homeostasis, apoptosis, or necrosis. To better understand the underlying molecular mechanisms after exposure to xenobiotics or drugs, we studied the signal transduction pathways, the mitogen-activated protein kinase (MAPK), and the basic leucine zipper transcription factor Nrf2, activated by different agents in the induction of Phase II drug metabolizing enzymes (DMEs). The MAPKs, characterized as proline-directed serine/threonine kinases, are essential components of signaling pathways that convert various extracellular signals into intracellular responses through serial phosphorylation cascades. Once activated, MAPKs can phosphorylate many transcription factors, such as c-Jun, ATF-2, and ultimately lead to changes in gene expression. Two classes of Phase II gene inducers, which are also cancer chemopreventive agents, were studied: (1) the phenolic antioxidants, namely butylated hydroxyanisole (BHA) and its active de-methylated metabolite t-butylhydroquinone (tBHQ), and phenolic flavonoids such as green tea polyphenols (GTP) and (-)-epigallocatechin-3-gallate (EGCG); and (2) the naturally occurring isothiocyanates, namely phenethyl isothiocyanate (PEITC), and sulforaphane. BHA and tBHQ are both well-known phenolic antioxidants used as food preservatives, and strongly activate c-Jun N-terminal kinase 1 (JNK1), extracellular signal-regulated protein kinase 2 (ERK2), or p38, in a time- and dose-dependent fashion. Free radical scavengers N-acetyl-L-cysteine (NAC), or glutathione (GSH), inhibited ERK2 activation and, to a much lesser extent, JNK1 activation by BHA/tBHQ, implicating the role of oxidative stress. Under conditions where MAPKs were activated, BHA or GTP also activated ARE/EpRE (antioxidant/electrophile response element), with the induction of Phase II genes such as NQO. Transfection studies with various cDNAs encoding wild-type or dominant-negative mutants of MAPKs and/or transcription factor Nrf2, substantially modulated ARE-mediated luciferase reporter activity in the presence or absence of phenolic compounds. Other phytochemicals including PEITC, and sulforaphane, also differentially regulated the activities of MAPKs, Nrf2, and ARE-mediated luciferase reporter gene activity and Phase II enzyme induction. A model is proposed where these xenobiotics (BHA, tBHQ, GTP, EGCG, PEITC, sulforaphane) activate the MAPK pathway via an electrophilic-mediated stress response, leading to the transcription activation of Nrf2/Maf heterodimers on ARE/EpRE enhancers, with the subsequent induction of cellular defense/detoxifying genes including Phase II DMEs, which may protect the cells against toxic environmental insults and thereby enhance cell survival. The studies of these signaling pathways may yield insights into the fate of cells upon exposure to xenobiotics.

Inhibition of egg hatching success and larvae survival of the scallop, Chlamys farreri, associated with exposure to cells and cell fragments of the dinoflagellate Alexandrium tamarense

We report an apparently novel toxic effect of the dinoflagellate Alexandrium tamarense, manifested by inhibition of the egg hatching success of the scallop, Chlamys farreri. The hatching rate of C. farreri approached only 30% of controls when its fertilised eggs were exposed for 36h to A. tamarense cells or cellular fragments at a concentration of 100 cells/ml, and the hatching rate was just 5% after exposure to A. tamarense of 500 cells/ml. Similar exposures of the fertilised scallop eggs to two other algal species, the diatom Phaeodactylum tricornutum and the raphidophyte Heterosigma carterae, resulted in no such toxicity or inhibitory effects. Likewise, exposure of eggs to standard STX toxin, as well as to A. tamarense cell contents (supernant of re-suspended algal cells following ultrasonication and centrifugation), did not elicit this inhibitory response. However, exposure of the scallop eggs to cell cultures, intact algal cells, or cell fragments of A. tamarense produced marked toxicity. The alga also influenced larvae at early D-shape stage of scallop. The survival rates began to decrease significantly after exposed for 6 days at concentration of 3000 cells/ml and above; no larvae could survive after 14-day exposure to A. tamarense at 10,000 cells/ml or 20-day at 5000 cells/ml. The results indicated the production of novel substances from A. tamarense which can cause adverse effects on egg hatching and survival of the scallop larvae. The experiment also found that the developmental stages before blastula was the developmental period most sensitive to the A. tamarense toxin(s) and the alga at early exponential stage had the strongest effect on egg hatching comparing with other growth phases. The adverse effect of A. tamarense on early development of scallops may cause decline of shellfish population and may have further impact on marine ecosystem.

[Imaging diagnosis of intestinal tuberculosis]

OBJECTIVE

To assess significance and limitation of CT and radiological gastrointestinal examination in the diagnosis of the intestinal tuberculosis.

METHODS

22 cases of intestinal tuberculosis proven pathologically were analyzed. CT scans and radiological examination were performed (barium meal examination in 18 cases, intestinal or colonic double contrast examination in 10 cases and hypotonic duodenography in 3 cases).

RESULTS

Sensitivity and specificity of diagnosing the intestinal tuberculosis with CT were inferior than that with radiological examination. Lesions in small intestine (not including ileocecal region) were not easily identified by CT scan. However, CT scan was more preferable in identifying abdominal tuberculosis other than intestinal tuberculosis, especially typical tuberculous lymphadenopathy. Intestinal radiological examination was of great significance for the assessment of the status of intestinal tuberculosis by demonstrating mucosal alterations, morphologic appearance of ulcer, bowel deformation, and the involvement of lesion and fissures.

CONCLUSIONS

Gastrointestinal radiological examination and CT scans possess their diagnostic value, but have limitation in diagnosis of intestinal tuberculosis. CT scans combined with gastrointestinal radiological examination further improve the accuracy of diagnosis.

Resveratrol inhibits phorbol ester and UV-induced activator protein 1 activation by interfering with mitogen-activated protein kinase pathways

Resveratrol, a phenolic compound found in grapes and other food products, prevents chemical-induced carcinogenesis in a number of animal models of cancers. To better understand its chemopreventive property, we examined effects of resveratrol on the activity of activator protein 1 (AP-1), a dimeric transcription factor that plays a critical role in the carcinogenesis and tumor transformation. Pretreatment of HeLa cells with resveratrol inhibited the transcription of AP-1 reporter gene by UVC and phorbol 12-myristate 13-acetate (PMA). Pretreatment with resveratrol also inhibited the activation of extracellular signal-regulated protein kinase 2 (ERK2), c-jun N-terminal kinase 1 (JNK1), and p38. Selectively blocking mitogen-activated protein kinase (MAPK) pathways by overexpression of dominant-negative mutants of kinases attenuated the AP-1 activation by PMA and UVC. Interestingly, resveratrol had little effect on the induction of AP-1 reporter gene by active Raf-1, MEKK1, or MKK6, suggesting that it inhibited MAPK pathways by targeting the signaling molecules upstream of Raf-1 or MEKK1. Indeed, incubation of resveratrol with the isolated c-Src protein tyrosine kinase and protein kinase C diminished their kinase activities. Furthermore, inhibition of protein tyrosine kinases and protein kinase C with their selective inhibitors impaired the activation of MAPKs as well as the induction of AP-1 activity by PMA and UVC. In addition, modulation of estrogen receptor activity with 17beta-estradiol had no effect on the inhibition of AP-1 by resveratrol. Taken together, these results suggest that the effects of resveratrol on AP-1 and MAPK pathways may involve the inhibition of both protein tyrosine kinases and protein kinase C.

Glycolic acid treatment increases type I collagen mRNA and hyaluronic acid content of human skin

BACKGROUND

Chronic solar irradiation results in both morphologic and functional changes in affected skin. alpha-hydroxy acids, such as glycolic acid, have been shown to improve photodamaged skin.

OBJECTIVE

To investigate alterations in collagen gene induction and epidermal and dermal hyaluronic acid production as a result of administered glycolic acid.

METHODS

In this study we compared collagen gene expression from skin biopsy specimens, and epidermal and dermal hyaluronic acid immunohistochemical staining between glycolic acid-treated and vehicle-treated skin. Forearm skin was treated with 20% glycolic acid lotion or a lotion vehicle control twice a day for 3 months.

RESULTS

Epidermal and dermal hyaluronic acid and collagen gene expression were all increased in glycolic acid-treated skin as compared to vehicle-treated controls.

CONCLUSION

Our data suggest that epidermal and dermal remodeling of the extracellular matrix results from glycolic acid treatment. Longer treatment intervals may result in collagen deposition as suggested by the measured increase in mRNA.

His-His-Leu, an angiotensin I converting enzyme inhibitory peptide derived from Korean soybean paste, exerts antihypertensive activity in vivo

It has been reported that soybean peptide fractions isolated from Korean fermented soybean paste exert angiotensin I converting enzyme (ACE) inhibitory activity in vitro. In this study, further purification and identification of the most active fraction inhibiting ACE activity were performed, and its antihypertensive activity in vivo was confirmed. Subsequently, a novel ACE inhibitory peptide was isolated by preparative HPLC. The amino acid sequence of the isolated peptide was identified as His-His-Leu (HHL) by Edman degradation. The IC(50) value of the HHL for ACE activity was 2.2 microg/mL in vitro. Moreover, the synthetic tripeptide HHL (spHHL) resulted in a significant decrease of ACE activity in the aorta and led to lowered systolic blood pressure (SBP) in spontaneously hypertensive (SH) rats compared to control. Triple injections of spHHL, 5 mg/kg of body weight/injection resulted in a significant decrease of SBP by 61 mmHg (p < 0.01) after the third injection. These results demonstrated that the ACE inhibitory peptide HHL derived from Korean fermented soybean paste exerted antihypertensive activity in vivo.

Cone beam volume CT image artifacts caused by defective cells in x-ray flat panel imagers and the artifact removal using a wavelet-analysis-based algorithm

The application of x-ray flat panel imagers (FPIs) in cone beam volume CT (CBVCT) has attracted increasing attention. However, due to a deficient semiconductor array manufacturing process, defective cells unavoidably exist in x-ray FPIs. These defective cells cause their corresponding image pixels in a projection image to behave abnormally in signal gray level, and result in severe streak and ring artifacts in a CBVCT image reconstructed from the projection images. Since a three-dimensional (3-D) back-projection is involved in CBVCT, the formation of the streak and ring artifacts is different from that in the two-dimensional (2-D) fan beam CT. In this paper, a geometric analysis of the abnormality propagation in the 3D back-projection is presented, and the morphology of the streak and ring artifacts caused by the abnormality propagation is investigated through both computer simulation and phantom studies. In order to calibrate those artifacts, a 2D wavelet-analysis-based statistical approach to correct the abnormal pixels is proposed. The approach consists of three steps: (1) the location-invariant defective cells in an x-ray FPI are recognized by applying 2-D wavelet analysis on flat-field images, and a comprehensive defective cell template is acquired; (2) based upon the template, the abnormal signal gray level of the projection image pixels corresponding to the location-invariant defective cells is replaced with the interpolation of that of their normal neighbor pixels; (3) that corresponding to the isolated location-variant defective cells are corrected using a narrow-windowed median filter. The CBVCT images of a CT low-contrast phantom are employed to evaluate this proposed approach, showing that the streak and ring artifacts can be reliably eliminated. The novelty and merit of the approach are the incorporation of the wavelet analysis whose intrinsic multi-resolution analysis and localizability make the recognition algorithm robust under variable x-ray exposure levels between 30% and 70% of the dynamic range of an x-ray FPI.

Synergistic protection of allopregnanolone and phenobarbital against maximal electroshock seizures in mice

AIM

To examine the interactions of allopregnanolone and phenobarbital for the protection against seizures.

METHODS

The protective activity of allopregnanolone and/or phenobarbital against seizures was studied in the C57 mice, using the maximal electroshock seizure (MES) test. The modulations by allopregnanolone and/or phenobarbital at the GABA(A) receptor were also characterized using the [3H]flunitrazepam binding in the membrane preparation of mouse cerebral cortex.

RESULTS

Pretreatment with phenobarbital produced a dose-dependent protective effect against seizures. The ED50 value of phenobarbital was 2.61 (95 % confidence limits: 1.59 - 4.26) mg . kg-1. Likewise, the ED50 value of allopregnanolone was 0.11 (0.06 - 0.18) mg . kg-1. The combination of allopregnanolone and phenobarbital (1:20) resulted in an ED50 value of 0.73 (0.44 - 1.21) mg . kg-1 with the Q value smaller than 1. In measuring the enhancement of [3H]flunitrazepam binding, we found that the pattern for the concentration-effect curves of phenobarbital with or without allopregnanolone was consistent with that of the theoretical curves of functional synergism.

CONCLUSION

There was a synergism between allopregnanolone and phenobarbital for the protective activity against seizures. Also there was a functional synergism between these two agents for the enhancement of [3H]flunitrazepam binding to the GABAA receptor complex in the brain.

Practical synthesis, separation, and stereochemical assignment of the PMPA pro-drug GS-7340

The practical synthesis of a mixed phenoxy-amidate derivative of PMPA with high oral bioavailability and favorable pharmacokinetics is described. The non-stereoselective synthetic route produces a 1:1 mixture of two diastereomers at phosphorous. Simulated moving bed chromatography using Chiralpak AS enabled kilo-scale isolation of the more potent diastereomer (GS-7340). The GS-7340 phosphorous chiral center was found to be (S) by X-ray crystallography.

Modulation of proliferating cell nuclear antigen in the bronchial epithelium of smokers

Clinical chemoprevention trials seek to intervene in the carcinogenic process to suppress, reverse, or delay the development of invasive cancer. Dysregulated cell growth is a hallmark of epithelial carcinogenesis, and proliferating cell nuclear antigen (PCNA) is a marker of dysregulated proliferation that is highly expressed in non-small cell lung cancers. Squamous metaplasia of the bronchial epithelium is found in chronic smokers and has been considered an early premalignant change. To evaluate the effect of 13-cis-retinoic acid (13-cRA) on PCNA modulation, we evaluated PCNA expression in a total of 706 bronchial biopsy specimens from histologically normal, hyperplastic, metaplastic, and dysplastic bronchial tissues obtained from 86 healthy smokers at baseline, of whom 69 subjects had completed 6 months of treatment on a randomized placebo-controlled chemoprevention trial of 13-cRA and had repeat bronchoscopic biopsies. PCNA expression was evaluated with respect to bronchial metaplasia and as an intermediate end point for response in the trial. In the bronchial biopsies obtained from six standardized pretreatment and posttreatment sites, high PCNA expression correlated significantly with more advanced histological grade (P < 0.001). Furthermore, smoking cessation during therapy correlated well with reduced PCNA expression (P = 0.006), although multivariate analysis indicated that this reduction in PCNA expression was associated with the reversal of squamous metaplasia. The level of PCNA expression appeared to correlate with the level of epidermal growth factor receptor expression both at baseline and at 6 months. In those patients who ceased smoking during the intervention, the 13-cRA also appeared to be more effective than placebo in reducing PCNA expression (P = 0.034 in all of the layers; P = 0.026 in basal layers). The efficacy of 13-cRA in the down-regulation of PCNA in quitters was independent of baseline PCNA expression levels. Our study demonstrated that increased PCNA expression was associated with histological progression from normal bronchial epithelium to squamous metaplasia and dysplasia. The modulation of PCNA by 13-cRA in patients who quit smoking suggests a potentially important role for regulating this proliferation marker in retinoid chemoprevention studies of former smokers.

[The combination of cyclosporin A and androgen in the treatment of chronic aplastic anemia]

OBJECTIVE

To explore the therapeutic effectiveness of combination of cyclosporin A (CsA) and androgen in the treatment of chronic aplastic anemia (CAA).

METHOD

Androgen alone or combined with CsA for the treatment of CAA was compared by a randomized controlled clinical trial.

RESULT

The efficacy of androgen combined with CsA (87.9%) was higher than that of androgen alone (57.1%). Therapeutic effectiveness of the combination treatment between the patients with positive and negative peripheral blood mononuclear cells (PBMNCs) inhibiting normal colony formation unit-granulocyte and macrophage (CFU-GM) test showed a significant difference (P < 0.005).

CONCLUSION

Androgen combined with CsA had a much better efficacy than that of androgen alone in the treatment of CAA. The patients' PBMNCs inhibiting normal CFU-GM growth test can be used as an index of the treatment outcome. The side effects of the combination therapy are low and tolerable.

Increased activity of protein kinase C in alveolar macrophages in idiopathic pulmonary fibrosis

OBJECTIVE

To investigate the changes on protein kinase C (PKC) activity of alveolar macrophages (AMs) in patients with idiopathic pulmonary fibrosis (IPF).

METHODS

The PKC activity of AM in 9 healthy volunteers and 15 patients with IPF was investigated by measuring the radioactivity.

RESULTS

The total, cytosolic and membrane PKC activity of AM in bronchoalveolar lavage fluid (BALF) from patients with IPF were higher than those from control group (P < 0.01, P < 0.05 and P < 0.05, respectively). The total and the membrane-associated PKC activity had a positive correlation with the number of cells in BALF (r = 0.8135, P < 0.01 and r = 0.5917, P < 0.05), respectively.

CONCLUSION

As a bypass of transmembrane signal transduction, PKC was suggested to be involved in the origination and development of IPF.

Phase I trial of 40-kd branched pegylated interferon alfa-2a for patients with advanced renal cell carcinoma

PURPOSE

Pegylated (40 kd) interferon alfa-2a (IFNalpha2a) (PEGASYS, Hoffman-La Roche, Nutley, NJ; PEG-IFN) is a modified form of recombinant human IFNalpha2a with sustained absorption and prolonged half-life after subcutaneous administration. A phase I study of PEG-IFN with pharmacokinetic and pharmacodynamic evaluations was conducted in previously untreated patients with advanced renal cell carcinoma (RCC).

PATIENTS AND METHODS

Twenty-seven patients were enrolled onto cohorts of three or six patients. PEG-IFN was administered on a weekly basis by subcutaneous injection. The dose was escalated from 180 microg/wk to a maximum of 540 microg/wk in 90-microg increments. Serial venous blood samples were drawn to assess concentrations of PEG-IFN and two immunologic surrogates, neopterin and 2'-5' oligoadenylate synthetase (OAS).

RESULTS

The maximum-tolerated dose was determined as 540 microg/wk, because two patients experienced dose-limiting toxicity within 28 days of starting treatment. One developed serum grade 3 ALT elevation, and a second developed grade 3 fatigue. Six patients were treated at 450 microg/wk without dose-limiting toxicity. Over the course of treatment, the side-effect profile was mostly mild to moderate in intensity. Adverse events included fatigue, fever, headache, myalgia, nausea, and decreased appetite. Five patients (19%) achieved a partial response. The mean maximum serum concentration increased from 5.0 to 27 ng/mL, and mean area under the curve increased from 247 to 2,981 ng/h/mL, with dose escalation from 180 microg/wk to 540 microg/wk. Serum concentration of PEG-IFN was sustained at close to peak during the dosing interval, and steady-state was achieved in approximately 5 weeks. The immunologic surrogates, neopterin and OAS, were induced at all doses with a sustained concentration profile similar to PEG-IFN.

CONCLUSION

PEG-IFN is a modified form of IFNalpha2a with distinct pharmacokinetic advantages and immunomodulatory and antitumor activity for patients with advanced RCC. A dose of 450 microg/wk by subcutaneous administration was determined as a suitable dose for further study. PEG-IFN is more convenient to administer than IFNalpha and has potential for increased efficacy, less toxicity, or both. The efficacy and toxicity of PEG-IFN will be further assessed in clinical trials and compared with IFNalpha.

Human pituitary tumor-transforming gene induces angiogenesis

Angiogenesis is a key determinant and rate-limiting step in tumor progression and metastatic spread. As pituitary tumor-transforming gene (PTTG) induces basic fibroblast growth factor (bFGF), we tested angiogenesis induced by conditioned medium (CM) derived from NIH-3T3 transfectants overexpressing wild-type human PTTG (WT-hPTTG-CM). We also examined the relationship between PTTG expression and tumor vascularity in a series of human tumors. CM from Wt-hPTTG transfectants induced proliferation, migration, and tube formation of human umbilical vein endothelial cells in vitro. The bFGF concentration in WT-hPTTG-CM was elevated (10.5 +/- 0.56) compared with CM from nontransfected NIH-3T3 cells (3.3 +/- 0.56 pg/mL), and addition of anti-bFGF antibody to CM abrogated these angiogenesis markers (P < 0.01). In vivo, concentrated WT-hPTTG-CM induced chick chorioallantoic membrane spoke-wheel-like appearances. Moreover, CM derived from hPTTG transfectants harboring a point mutation on the C-terminus proline-rich region of PTTG induced weaker angiogenic activity than WT-hPTTG-CM (P < 0.01). Thus, human PTTG induces an angiogenic phenotype in both in vitro and in vivo angiogenesis models, and high PTTG messenger ribonucleic acid is associated with an angiogenic phenotype in human tumors. These PTTG-directed angiogenic actions may be mediated through bFGF, which also contributes to tumor growth.

Pituitary tumor transforming gene (PTTG) regulates placental JEG-3 cell division and survival: evidence from live cell imaging

The pituitary transforming gene, PTTG, is abundantly expressed in endocrine neoplasms. PTTG has recently been recognized as a mammalian securin based on its biochemical homology to Pds1p. PTTG expression and intracellular localization were therefore studied during the cell cycle in human placental JEG-3 cells. PTTG mRNA and protein expressions were low at the G1/S border, gradually increased during S phase, and peaked at G2/M, but PTTG levels were attenuated as cells entered G1. In interphase cells, wild-type PTTG, an epitope-tagged PTTG, and a PTTG-EGFP conjugate all localized to both the nucleus and cytoplasm, but in mitotic cells, PTTG was not observed in the chromosome region. PTTG-EGFP colocalized with mitotic spindles in early mitosis and was degraded in anaphase. Intracellular fates of PTTG-EGFP and a conjugate of EGFP and a mutant inactivated PTTG devoid of an SH3-binding domain were observed by real-time visualization of the EGFP conjugates in live cells. The same cells were continuously observed as they progressed from G1/S border to S, G2/M, and G1. Most cells (67%) expressing PTTG-EGFP died by apoptosis, and few cells (4%) expressing PTTG-EGFP divided, whereas those expressing mutant PTTG-EGFP divided. PTTG-EGFP, as well as the mutant PTTG-EGFP, disappeared after cells divided. The results show that PTTG expression and localization are cell cycle-dependent and demonstrate that PTTG regulates endocrine tumor cell division and survival.

Microtubule dynamics are involved in stomatal movement of Vicia faba L

To obtain a full picture of microtubule (MT) behavior during the opening and closure of guard cells we have microinjected living guard cells of Vicia faba with fluorescent tubulin, examined fine detail by freeze shattering fixed cells, and used drug treatments to confirm aspects of MT dynamics. Cortical MTs in fully opened guard cells are transversely oriented from the ventral wall to the dorsal wall. When the stomatal aperture was decreased by darkness, these MTs became twisted and patched and broken down into diffuse fragments when stomata were closed. When the closed stomata were opened in response to light, the MTs in guard cells changed from the diffused, transitional pattern back to one in which MTs are transversely oriented from stomatal pore to dorsal wall. This observation indicates a linkage between these MT changes and stomatal movement. To confirm this, we used the MT-stabilizing agent taxol and the MT-depolymerizing herbicide oryzalin and observed their effects on the stomatal aperture and MT dynamics. Both drugs suppressed light-induced stomatal opening and dark-induced closure. MTs are known to be necessary for maintaining the static kidney shape of guard cells; the present data now show that the dynamic properties of polymeric tubulin accompany changes in shape with stomatal movement and may be functionally involved in stomatal movement.

[Association of vascular endothelial growth factor expression with angiogenesis and tumor cell proliferation in human lung cancer]

OBJECTIVE

To evaluate the expression of vascular endothelial growth factor (VEGF) and the relation with angiogenesis and tumor cell proliferation in human lung cancer.

METHODS

Expression of VEGF, angiogenesis, tumor cell proliferation in 63 cases of human lung cancer were examined immunohistochemically. Anti-VEGF(165)-Ab3 was used for VEGF expression, a monoclonal antibody directed against CD(34) to identify intratumoral microvessel density (iMVD) and the proliferating cell nuclear antigen (PCNA) as a marker of proliferating tumor cells.

RESULTS

Positive staining for VEGF was obtained in 32 of the 63 cases (50.8%), iMVD varied from 4 to 138.7 (M = 36)/x 400 and the proportion of PCNA positive cells varied from 0 to 92% (M = 25.03%). iMVD in high-grade VEGF tumors was significantly higher than that in VEGF-negative tumors and low-grade VEGF tumors. PCNA labeling proliferation index in small cell lung cancer was higher than that in non-small cell lung cancer. iMVD significantly increased with increasing VEGF expression.

CONCLUSION

There is VEGF expression in lung cancer. VEGF expression is significantly associated with iMVD, but there is no association between iMVD or VEGF expression and PCNA expression. There is no association between VEGF expression and histological classification and clinical stages.