Soluble carbohydrate concentration and expression of expansin and xyloglucan endotransglucosylase/hydrolase genes in epidermal and parenchyma cells during lily flower opening

To understand the biochemical mechanism underlying flower opening, the manner of cell expansion, soluble carbohydrate concentration, and expression of expansin and xyloglucan endotransglucosylase/hydrolase (XTH) genes were investigated in the petals of Oriental lily (Lilium 'Sorbonne'). Microscopic observation revealed that petal growth during flower opening mainly depended on cell expansion, which was accompanied by increases in glucose and fructose concentrations in the petals. The adaxial and abaxial sides of the petals grew at different rates during flower opening with petal reflection. To determine the concentration of soluble carbohydrates and the expression of expansin and XTH genes in adaxial and abaxial epidermal cells and parenchyma cells, these cells were separated using tweezers. We confirmed that these cells could be sufficiently separated. Glucose and fructose concentrations were higher in adaxial epidermal cells than in abaxial epidermal cells at the stage immediately preceding flower opening, but these differences diminished during flower opening. Three expansin genes, LhEXPA1, LhEXPA2, and LhEXPA3, and two XTH genes, LhXTH1 and LhXTH2 were isolated. LhXTH1 transcript levels in the petals markedly increased during flower opening and were higher in adaxial epidermal cells than in other types of cells. Conversely, the levels of the three EXPA transcripts decreased during flower opening and there were slight differences in their levels among different cell types, with a few exceptions. In conclusion, differences in glucose and fructose concentrations between adaxial and abaxial epidermal cells, together with the expression of LhXTH1, may contribute to cell expansion associated with flower opening.

A novel thin section preparation and staining protocol to increase contrast and resolution of cell details for light microscopy

We developed a novel sectioning and staining method to make high contrast, high resolution sections of plant tissue for light microscopy. Specimens of teosinte (Zea mays L., ssp. mexicana) root tips were fixed and embedded in Technovit 7100™ plastic resin. Thin sections, 1-2.5 μm, were cut and mounted on glass slides. The sections were either treated with RNase or not, then stained with 0.1% toluidine blue O and observed through ∞/0 objective lenses. For light microscopy, the enzyme staining procedure increased resolution and contrast. High magnification ∞/0 objective lenses produced high quality images for digital photography without using a coverslip or immersion oil. Our slide preparation and microscopic analysis were less labor intensive and more rapid than previous methods and enabled rapid and precise alignment of serial transverse sections for both tracking cell lineages and tissue measurements.

Accumulation of mannitol in the cytoplasm and vacuole during the expansion of sepal cells associated with flower opening in Delphinium × belladonna cv. Bellamosum

The role of mannitol differs from that of glucose, fructose and sucrose in sepal cell expansion associated with flower opening in Delphinium × belladonna. Sepals of Delphinium × belladonna are colored and much larger than the petals. To determine whether the role of mannitol in sepal growth associated with flower opening differs from those of ubiquitous metabolic sugars including glucose, fructose and sucrose, we investigated changes in cell number, subcellular concentrations of soluble carbohydrates, and osmotic potential in sepals during flower opening in Delphinium × belladonna cv. Bellamosum. The number of epidermal cells in the sepals did not increase from the stage when sepal pigmentation started, whereas the cell area increased during flower opening, indicating that petal growth during flower opening depends on cell expansion. Mannitol concentrations in the vacuole at three different stages were approximately 100 mM, which were much higher than the other carbohydrate concentrations, but they decreased slightly at open stage. In contrast, mannitol concentration in the cytoplasm was 56 mM at bud stage, but it increased to 104 mM at open stage. Glucose and fructose concentrations in the vacuole at open stage increased to 45 and 56 mM, respectively. Total osmotic potential in apoplast and symplast, which was partially due to soluble carbohydrates, was almost constant during flower opening. Therefore, mannitol may be acting constitutively as the main osmoticum in the vacuole where it may contribute to the maintenance of the osmotic balance between the cytoplasm and vacuole in open flowers. The role of mannitol differs from those of glucose, fructose, and sucrose in sepal cell expansion in Delphinium × belladonna.

Programmed Cell Death Progresses Differentially in Epidermal and Mesophyll Cells of Lily Petals

In the petals of some species of flowers, programmed cell death (PCD) begins earlier in mesophyll cells than in epidermal cells. However, PCD progression in each cell type has not been characterized in detail. We separately constructed a time course of biochemical signs and expression patterns of PCD-associated genes in epidermal and mesophyll cells in Lilium cv. Yelloween petals. Before visible signs of senescence could be observed, we found signs of PCD, including DNA degradation and decreased protein content in mesophyll cells only. In these cells, the total proteinase activity increased on the day after anthesis. Within 3 days after anthesis, the protein content decreased by 61.8%, and 22.8% of mesophyll cells was lost. A second peak of proteinase activity was observed on day 6, and the number of mesophyll cells decreased again from days 4 to 7. These biochemical and morphological results suggest that PCD progressed in steps during flower life in the mesophyll cells. PCD began in epidermal cells on day 5, in temporal synchrony with the time course of visible senescence. In the mesophyll cells, the KDEL-tailed cysteine proteinase (LoCYP) and S1/P1 nuclease (LoNUC) genes were upregulated before petal wilting, earlier than in epidermal cells. In contrast, relative to that in the mesophyll cells, the expression of the SAG12 cysteine proteinase homolog (LoSAG12) drastically increased in epidermal cells in the final stage of senescence. These results suggest that multiple PCD-associated genes differentially contribute to the time lag of PCD progression between epidermal and mesophyll cells of lily petals.

Ethylene production associated with petal senescence in carnation flowers is induced irrespective of the gynoecium

To clarify whether climacteric-like increases in ethylene production of senescing petals are also induced in the absence of the gynoecium in cut carnation (Dianthus caryophyllus cv. Barbara) flowers, we compared ethylene production and expression of ethylene-biosynthesis genes in detached petals and in petals, which remained on flowers (attached petals). No significant difference in longevity was observed between the attached and detached petals when held in distilled water, and both showed the inward rolling typical of senescing flowers. Treatment with silver thiosulfate complex (STS), an ethylene inhibitor, similarly delayed senescence of attached and detached petals. Climacteric-like increases in ethylene production of petals and gynoecium started on the same day, with similar bursts in attached and detached petals. Transcript levels of DcACS1 and DcACO1 were very low at harvest and increased similarly during senescence in both petal groups. Removal of the gynoecium did not significantly delay wilting of attached petals. In flowers with the gynoecium removed, the petals produced most of the ethylene while production by the other floral organs was very low, suggesting that wound-induced ethylene is not the reason for the ineffectiveness of gynoecium-removal in inhibiting flower senescence. These results indicate that ethylene biosynthesis is induced in carnation petals irrespective of the gynoecium.

Identification of a NAC transcription factor, EPHEMERAL1, that controls petal senescence in Japanese morning glory

In flowering plants, floral longevity is species-specific and is closely linked to reproductive strategy; petal senescence, a type of programmed cell death (PCD), is a highly regulated developmental process. However, little is known about regulatory pathways for cell death in petal senescence, which is developmentally controlled in an age-dependent manner. Here, we show that a NAC transcription factor, designated EPHEMERAL1 (EPH1), positively regulates PCD during petal senescence in the ephemeral flowers of Japanese morning glory (Ipomoea nil). EPH1 expression is induced independently of ethylene signaling, and suppression of EPH1 resulted in Japanese morning glory flowers that are in bloom until the second day. The suppressed expression of EPH1 delays progression of PCD, possibly through suppression of the expression of PCD-related genes, including genes for plant caspase and autophagy in the petals. Our data further suggest that EPH1 is involved in the regulation of ethylene-accelerated petal senescence. In this study, we identified a key regulator of PCD in petal senescence, which will facilitate further elucidation of the regulatory network of petal senescence.

Comparison of preoperative chemotherapy using docetaxel, cisplatin and fluorouracil with cisplatin and fluorouracil in patients with advanced carcinoma of the thoracic esophagus

We retrospectively compared preoperative docetaxel, cisplatin, and fluorouracil (DCF) with cisplatin and fluorouracil (CF) in patients with esophageal cancer. The study included patients with advanced thoracic esophageal carcinoma (excluding T4 tumors) receiving preoperative chemotherapy. In the DCF group, five patients received two courses of treatment every 4 weeks, and 33 patients received three courses every 3 weeks. In the CF group, 38 patients received two courses of treatment every 4 weeks. Patients underwent curative surgery 4-5 weeks after completing chemotherapy. Patient demographic characteristics did not differ between the two study groups. The incidence of a grade 3 or 4 hematologic toxicity was significantly higher in the DCF group (33 patients) than in the CF group (five patients; P < 0.001). Curative resection was accomplished in 79% of patients in the DCF group and 66% in the CF group (P = 0.305). There were no in-hospital deaths. The incidence of perioperative complications did not differ between the groups. A grade 2 or 3 histological response was attained in a significantly higher proportion of patients in the DCF group (63%) than in the CF group (5%; P < 0.001). Progression-free survival and overall survival were significantly higher in the DCF group (P = 0.013, hazard ratio 0.473; P = 0.001, hazard ratio 0.344). In conclusion, a grade 3 or 4 hematologic toxicity was common in the DCF group but was managed by supportive therapy. Histological response rate, progression-free survival, and overall survival were significantly higher in the DCF group compared with the CF group.

Pollination induces autophagy in petunia petals via ethylene

Autophagy is one of the main mechanisms of degradation and remobilization of macromolecules, and it appears to play an important role in petal senescence. However, little is known about the regulatory mechanisms of autophagy in petal senescence. Autophagic processes were observed by electron microscopy and monodansylcadaverine staining of senescing petals of petunia (Petunia hybrida); autophagy-related gene 8 (ATG8) homologues were isolated from petunia and the regulation of expression was analysed. Nutrient remobilization was also examined during pollination-induced petal senescence. Active autophagic processes were observed in the mesophyll cells of senescing petunia petals. Pollination induced the expression of PhATG8 homologues and was accompanied by an increase in ethylene production. Ethylene inhibitor treatment in pollinated flowers delayed the induction of PhATG8 homologues, and ethylene treatment rapidly upregulated PhATG8 homologues in petunia petals. Dry weight and nitrogen content were decreased in the petals and increased in the ovaries after pollination in detached flowers. These results indicated that pollination induces autophagy and that ethylene is a key regulator of autophagy in petal senescence of petunia. The data also demonstrated the translocation of nutrients from the petals to the ovaries during pollination-induced petal senescence.

[Aortic root replacement for aortic dissection and aortic regurgitation due to aortitis syndrome]

Aortic aneurysms and aortic regurgitation (AR) with aortitis syndrome are occasionally reported in young women. We report a case of aortic dissection with severe AR in an 8-year-old girl. The patient underwent aortic root replacement with a composite graft. Pathological report revealed aortitis syndrome and steroid therapy was continued to suppress further inflammatory vascular reaction.

Cytoplasmic localization of p63 is associated with poor patient survival in lung adenocarcinoma

AIMS

To determine the significance of p63 protein expression in the development and progression of lung adenocarcinoma.

METHODS AND RESULTS

The expression of p63 was immunohistochemically investigated in 92 cases of lung adenocarcinoma with a maximum diameter of 30 mm or less. p63 expression was observed not only in the nuclei (46/92 cases, 50%), but also in the cytoplasm of neoplastic cells (47/92, 51%). Nuclear localization of p63 was correlated with nuclear accumulation of p53 (P=0.0120), whereas the presence of nuclear p63 had no apparent effect on patient survival. Cytoplasmic localization of p63 was found to be correlated with shorter survival periods by univariate and multivariate analyses (P=0.0486 and P=0.0488, respectively) and the relation was independent of clinicopathological factors. Cytoplasmic localization of p63 was further confirmed by immunoblots of the cytoplasmic fraction of HLC-1, a lung adenocarcinoma cell line which predominately expressed DeltaNp63alpha transcript relative to TAp63 transcript by quantitative reverse transcriptase-polymerase chain reaction.

CONCLUSIONS

Cytoplasmic expression of p63 is an adverse prognostic factor in patients with adenocarcinoma of the lung.

Proper SUMO-1 conjugation is essential to DJ-1 to exert its full activities

DJ-1 is a multifunctional protein that plays roles in transcriptional regulation and antioxidative stress, and loss of its function is thought to result in the onset of Parkinson's disease (PD). Here, we report that DJ-1 was sumoylated on a lysine residue at amino-acid number 130 (K130) by PIASxalpha or PIASy. The K130 mutation abrogated all of the functions of DJ-1, including ras-dependent transformation, cell growth promotion and anti-UV-induced apoptosis activities. Sumoylation of DJ-1 was increased after UV irradiation concomitant with a pI shift to an acidic point of DJ-1. Furthermore, L166P, a mutant DJ-1 found in PD patients, and K130RX, an artificial mutant containing four mutations in DJ-1, were improperly sumoylated, and they became insoluble, partly localized in the mitochondria and degraded by the proteasome system. Both L166P-expressing cells and DJ-1-knockdown cells were found to be highly susceptible to UV-induced cell apoptosis.

Prevalence of CD99 protein expression in pancreatic endocrine tumours (PETs)

AIMS

To determine the prevalence of CD99 expression in pancreatic endocrine tumours (PETs). We evaluated CD99 expression and analysed Ki67 labelling by immunohistochemistry in PETs.

METHODS AND RESULTS

Thirty-eight PETs from 33 patients were analysed. CD99 immunoreactivity was consistently observed in normal islets of the pancreas, regardless of the cell type. Tumours comprising more than 30% CD99+ cells were defined as positively immunoreactive for CD99. CD99 expression was observed in 20 of the 38 PETs examined, but not in any of the pancreatic tumours of other histological subtypes (10 ductal adenocarcinomas, five intraductal papillary-mucinous tumours, and two acinar cell tumours). Loss of CD99 expression was related to markers of worse prognosis for PET, including gross local invasion, metastasis to the lymph nodes or other organs, lymphatic or blood vessel invasion, and neuroendocrine carcinoma (NEC). Thus, CD99 expression may have an efficiency comparable to that of high Ki67 labelling index (5% or more) for prognostication.

CONCLUSIONS

CD99 expression was observed frequently and exclusively in PETs, and loss of CD99 expression in PETs was found to be associated with ominous prognostic indicators.

DJ-1 positively regulates the androgen receptor by impairing the binding of PIASx alpha to the receptor

DJ-1 was first identified as a novel candidate of the oncogene product that transformed mouse NIH3T3 cells in cooperation with an activated ras. Later DJ-1 was also found to be an infertility-related protein that was reduced in rat sperm treated with sperm toxicants that cause infertility in rats. To determine the functions of DJ-1, cDNAs encoding DJ-1-binding proteins were screened by the yeast two-hybrid method. Of several proteins identified, PIASx alpha/ARIP3, a modulator of androgen receptor (AR), was first characterized as the DJ-1-binding protein in this study. DJ-1 directly bound to the AR-binding region of PIASx alpha by an in vitro coimmunoprecipitation assay and also bound to PIASx alpha in human 293T cells. Both proteins were co-localized in the nuclei. PIASx alpha inhibited the AR transcription activity in a dose-dependent manner in cotransfected monkey CV1 cells with an androgen responsive element-luciferase reporter. Introduction of DJ-1 into CV1 cells in a state of inhibition of AR activity by PIASx alpha restored AR transcription activity by absorbing PIASx alpha from the AR-PIASx alpha complex, while a DJ-1 mutant harboring an amino acid substitution at number 130 from lysine to arginine did not restore it. These results indicate that DJ-1 is a positive regulator of the androgen receptor.

Production of dwarf lettuce by overexpressing a pumpkin gibberellin 20-oxidase gene

We investigated the effect of overexpressing a pumpkin gibberellin (GA) 20-oxidase gene encoding an enzyme that forms predominantly biologically inactive products on GA biosynthesis and plant morphology in transgenic lettuce (Lactuca sativa cv Vanguard) plants. Lettuce was transformed with the pumpkin GA 20-oxidase gene downstream of a strong constitutive promoter cassette (El2-35S-Omega). The transgenic plants in which the pumpkin gene was detected by polymerase chain reaction were dwarfed in the T(2) generation, whereas transformants with a normal growth phenotype did not contain the transgene. The result of Southern-blot analysis showed that the transgene was integrated as a single copy; the plants segregated three dwarfs to one normal in the T(2) generation, indicating that the transgene was stable and dominant. The endogenous levels of GA(1) and GA(4) were reduced in the dwarfs, whereas large amounts of GA(17) and GA(25), which are inactive products of the pumpkin GA 20-oxidase, accumulated in these lines. These results indicate that a functional pumpkin GA 20-oxidase is expressed in the transgenic lettuce, resulting in a diversion of the normal pathway of GA biosynthesis to inactive products. Furthermore, this technique may be useful for controlling plant stature in other agricultural and horticultural species.

Trichostatin A, lead compound for development of antifibrogenic drugs

Eukaryotic gene expression has mainly been studied in the context of trans-acting transcription factors and their interaction with regulatory cis-elements. Evidence is accumulating, that the higher order structure of chromatin also plays an essential role in eukaryotic gene expression. Hepatic stellate cells are the major cellular source of extracellular matrix synthesis in chronic liver diseases leading to fibrosis. We explored the antifibrogenic effect of the histone deacetylase inhibitor trichostatin A (TSA) on hepatic stellate cells in vitro. Primary hepatic stellate cells as well as activated, subcultured stellate cells were exposed to 10(-7) M-10(-9) M TSA. Collagens type I and III, and smooth muscle alpha-actin (alpha-SMA), a marker for transdifferentiation, were investigated at the protein and mRNA level by performing Northern hybridisation and quantitative immunoprecipitation. The antiproliferative effect was examined by 3H-thymidine incorporation and cell counting. Hyperacetylation of histone H4 was demonstrated by acid urea Triton-X-100 (AUT) polyacrylamide gel electrophoresis. TSA at 10(-7) M retarded the morphological changes characteristics for activation of primary stellate cells. Synthesis of collagens type I and III, and alpha-SMA was strongly inhibited at both protein and mRNA level. The proliferation rate of primary hepatic stellate cells was strongly suppressed by 10(-7) M TSA. Hyperacetylation of histone H4 showed to be maximal at 10(-7) M TSA. Primary hepatic stellate cells were more affected by TSA than subcultured stellate cells.

Changes in growth and structure of pea primary roots (Pisum sativum L. cv. Alaska) as a result of sudden flooding

Pea (Pisum sativum L. cv. Alaska) primary roots were exposed to flooding after growth for 4 or 5 d at 25 degrees C under relatively dry conditions. Flooding after 4 d growth reduced, but did not stop, primary root growth, and cavities caused by degradation of central vascular cells were typically found from 10-60 mm from the tips. Flooding after 5 d stopped primary root growth and caused cell death in the tips, and vascular cavities formed that typically were 20-60 mm from the tips of the roots. Degradation of root tip cells in 5-day-roots was very rapid and began in the elongation zone and later in the apical zone. Root tips discolored, narrowed or curled before growth arrest. The mitotic indices of 5-day-root tips were suppressed by the flooding treatment. A few mitotic figures were observed in roots treated with flooding after 4 d growth. Affected cells had condensed nuclei, but cytoplasms appeared to be normal in the early stages of cell degradation. Later these cells became very vacuolated. The relationship of flooding to root growth, vascular cavity formation, and the morphology of pea primary roots is described with regard to the ability to resist flooding stress.

New aspects of sterol carrier protein 2 (nonspecific lipid-transfer protein) in fusion proteins and in peroxisomes

Sterol carrier protein 2 (SCP2) is a 13-kDa peroxisomal protein, identical to nonspecific lipid-transfer protein, and stimulates various steps of cholesterol metabolism in vitro. Although the name is reminiscent of acyl carrier protein, which is involved in fatty acid synthesis, SCP2 does not bind to lipids specifically or stoichiometrically. This protein is expressed either as a small precursor or as a large fusion (termed SCPx) that carries at its C-terminal the complete sequence of SCP2. SCPx exhibits 3-oxoacyl-CoA thiolase activity, as well as sterol-carrier and lipid-transfer activities. The N- and C-terminal parts of SCPx are similar to the nematode protein P-44 and the yeast protein PXP-18, respectively. P-44, which has no SCP2 sequence, thiolytically cleaved the side chain of bile acid intermediate at a rate comparable to that of SCPx. This, together with the properties of other fusions with SCP2-like sequence, suggests that the SCP2 part of SCPx does not play a direct role in thiolase reaction. PXP-18, located predominantly inside peroxisomes, is similar to SCP2 in primary structure and lipid-transfer activity, and protects peroxisomal acyl-CoA oxidase from thermal denaturation. PXP-18 dimerized at a high temperature, formed an equimolar complex with the oxidase subunit, and released the active enzyme from the complex when the temperature went down. This article attempts to gain insight into the role of SCP2, and to present a model in which PXP-18, a member of the SCP2 family, functions as a molecular chaperone in peroxisomes.

Pulmonary amyloidosis diagnosed by CT-guided transbronchial biopsy: a case report

During a medical check-up, a nodular shadow was detected by chest X-ray in the right lower lung field of a 59-year-old man. On computed tomography (CT), the nodular lesion had a relatively well-defined, irregular margin. A fluoroscopy-guided bronchoscopic biopsy did not uncover any malignancy. Specimens from a subsequent CT-guided bronchoscopic biopsy revealed a pulmonary amyloid deposit. As a rule, it is difficult to exclude malignancy or confirm benign disease in cases of truly benign lesions, particularly if the lesions are difficult to biopsy. Amyloidosis is one of such conditions and requires reliable diagnostic methods to avoid unnecessary surgical resection. From our experience, we consider CT-guided bronchoscopic biopsy to be a safe and accurate procedure, even when applied to truly benign lesions.

Primary synovial sarcoma of the lung: a case report confirmed by molecular detection of SYT-SSX fusion gene transcripts

We report a rare case of primary synovial sarcoma of the lung. The patient was a 49-year-old woman who presented with a well-defined oval-shaped mass in the left upper lobe on a chest radiograph. A malignant pulmonary tumor was suspected and consequently a left upper lobectomy was performed. Grossly, the tumor measured 5 x 4 cm, was whitish-yellow in color and soft in consistency. Histologically, the tumor showed a dense proliferation of short spindle cells, partly arranged in interlacing fascicles. In some areas a hemangiopericytoma-like pattern, stromal myxoid change and necrosis of various sizes were noted. Numerous mitotic figures were also seen. Immunohistochemically, the tumor cells were positive for epithelial markers such as cytokeratin and epithelial membrane antigen. As these features suggested a monophasic fibrous type of synovial sarcoma, we examined for the presence of SYT-SSXfusion gene transcripts using RNA samples from the frozen tumor tissue. A reverse transcription polymerase chain reaction amplified a single 583-base pair fragment characteristic of synovial sarcoma. As no other tumorous lesions were found during a follow-up period of 1 year, primary synovial sarcoma of the lung was our final diagnosis. This tumor should be considered in the differential diagnosis of round to short spindle cell tumors arising in the lung.

Expression of vascular endothelial growth factor receptor 3 in blood and lymphatic vessels of lung adenocarcinoma

Vascular endothelial growth factor receptor 3 (VEGFR-3) has been proposed as a marker for lymphatic endothelial cells. This study investigated the expression of VEGFR-3 in the tumour vessels of lung adenocarcinoma and evaluated whether VEGFR-3 staining was useful for identifying lymphatic vessels within the tumour stroma. It also explored whether active growth of lymphatic vessels occurred in lung adenocarcinoma. Formalin-fixed, paraffin-embedded specimens obtained from 60 cases of lung adenocarcinoma, including five cases of pure bronchiolo-alveolar carcinoma (BAC) without stromal, vascular, and pleural invasion, were examined. No VEGFR-3-positive vessels were observed in pure BAC, but varying numbers of VEGFR-3-positive vessels were found in 39 of 55 (70.9%) invasive adenocarcinomas. A comparison of serial sections stained for VEGFR-3, CD31, and laminin-1 showed that most of the VEGFR-3-positive vessels appeared to be blood vessels (CD31-positive, laminin-1-positive), but some had the characteristics of lymphatic vessels (variable staining for CD31, little or no staining for laminin-1). VEGFR-3 staining highlighted lymphatic invasion by cancer cells; this invasion could not be detected by CD31 or haematoxylin and eosin (H&E) staining. Active growth of lymphatic vessels (as indicated by nuclear Ki-67 labelling of the endothelium) was observed in five tumours, four of which showed a high level of lymphatic invasion by cancer cells. It was concluded that VEGFR-3 immunostaining did not discriminate clearly between vascular and lymphatic endothelial cells, since expression of VEGFR-3 can be up-regulated in tumour blood vessels. However, VEGFR-3 staining combined with laminin-1 and CD31 staining would be useful for identifying lymphatic vessels and their invasion by tumour cells in a more objective way. Finally, proliferation of lymphatic endothelial cells may occur in association with lymphatic invasion by cancer cells.

c-MET expression in myofibroblasts: role in autocrine activation and prognostic significance in lung adenocarcinoma

Hepatocyte growth factor (HGF) plays important roles in tumor development and progression. It is currently thought that the main action of HGF is of a paracrine nature: HGF produced by mesenchymal cells acts on epithelial cells that express its receptor c-MET. In this investigation, we explored the significance of c-MET expression in myofibroblasts, both in culture and in patients with lung adenocarcinoma. We first showed that human myofibroblasts derived from primary lung cancer expressed c-MET mRNA and protein by reverse transcription-polymerase chain reaction and Western blot analysis. Proliferation of myofibroblasts was stimulated in a dose-dependent manner by exogenously added recombinant human HGF whereas it was inhibited in a dose-dependent manner by neutralizing antibody to HGF. The addition of HGF in the culture medium stimulated tyrosine phosphorylation of c-MET. The c-MET protein was immunohistochemically detected in myofibroblasts in the invasive area of lung adenocarcinoma. Finally, the prognostic significance of c-MET expression in stromal myofibroblasts was explored in patients with small-sized lung adenocarcinomas. c-MET-positive myofibroblasts were observed in 69 of 131 cases (53%). A significant relationship between myofibroblast c-MET expression and shortened patient survival was observed in a whole cohort of patients including all pathological stages (two-sided P: = 0.0089 by log-rank test) and in patients with stage IA disease (two-sided P: = 0.0019 by log-rank test). These data suggest that the HGF/c-MET system constitutes an autocrine activation loop in cancer-stromal myofibroblasts. This autocrine system may play a role in invasion and metastasis of lung adenocarcinoma.

Increased expression of laminin-5 and its prognostic significance in lung adenocarcinomas of small size. An immunohistochemical analysis of 102 cases

BACKGROUND

Laminin-5 plays an important role in cell migration during tissue remodeling and tumor invasion.

METHODS

The authors studied the expression of laminin-5 immunohistochemically in 102 cases of small-sized lung adenocarcinoma (maximum dimension < or = 2 cm) using a monoclonal antibody against the laminin gamma2 chain, and they also investigated the associations of laminin-5 with clinicopathologic characteristics. Prognostic significance of increased laminin-5 expression was evaluated using the Kaplan-Meier method and the Cox proportional hazard model.

RESULTS

Overall, laminin-5 expression was observed in 82 cases (80.4%): 7 of 18 (38.9%) bronchioloalveolar carcinomas and 75 of 84 (89.3%) invasive adenocarcinomas. Laminin-5 was preferentially localized in the cytoplasm of tumor cells at the tumor-stromal interface, where budding or dissociation of cancer cells was frequently observed. Overexpression of laminin-5 (24 cases, 23.5%) was associated with vascular invasion (P = 0.021) and stromal fibroblastic reaction (P = 0.005) but not with nodal involvement, lymphatic invasion, or pleural invasion. Survival analysis revealed that overexpression of laminin-5 was associated with shorter patient survival (P = 0.0027 by log rank test). On multivariate analysis, overexpression of laminin-5 was an independent prognostic factor (P = 0.030), as were nodal involvement (P < 0.0001), vascular invasion (P = 0.047), and lymphatic invasion (P = 0.0047) in a whole cohort of patients. Moreover, when patients with Stage I (International Union Against Cancer [UICC] staging system) disease were considered in multivariate analysis, overexpression of laminin-5 was the only significant prognostic factor (P = 0.022), whereas vascular invasion had a marginally significant impact (P = 0.07) on patient survival.

CONCLUSIONS

The authors' results showed that laminin-5 is frequently expressed by cancer cells at the invasive front of lung adenocarcinoma. The study concluded that overexpression of laminin-5 may be a useful prognostic factor in patients with small-sized lung adenocarcinoma, especially in Stage I cases.

Effect of aldosterone on collagen steady state levels in primary and subcultured rat hepatic stellate cells

BACKGROUND/AIMS

Activation of the renin-angiotensin-aldosterone system can lead to collagen accumulation and reactive myocardial fibrosis. This study aims at evaluating the effect of aldosterone on extracellular matrix synthesis by rat hepatic stellate cells.

METHODS

Cultured cells were treated with different concentrations of aldosterone (10(-6)-10(-10) M) and metabolically labeled with 35S-methionine/35S-cysteine. Procollagen types I, III and IV, laminin and fibronectin were specifically immunoprecipitated and quantified by phosphor imaging. Using the reverse transcription-polymerase chain reaction, we investigated the expression of the mineralocorticoid receptor in hepatic stellate cells.

RESULTS

Quantitation showed that 10(-6) M aldosterone induced procollagen type I synthesis significantly, whereas procollagen type IV expression was significantly affected by 10(-9) and 10(-10) M aldosterone, both in primary hepatic stellate cells. RT-PCR experiments clearly demonstrated a lack of expression of the mineralocorticoid receptor in hepatic stellate cells.

CONCLUSION

We demonstrated that aldosterone altered moderately procollagen type I and IV synthesis by primary hepatic stellate cells, but not by activated stellate cells which are the principal cellular sources of extracellular matrix proteins in chronic liver disease. Moreover, hepatic stellate cells do not express the mineralocorticoid receptor, suggesting that the observed modest changes of extracellular matrix synthesis are probably due to mineralocorticoid receptor unrelated mechanisms.

Formation of normal desmin intermediate filaments in mouse hepatic stellate cells requires vimentin

Increased desmin synthesis and formation of desmin-containing intermediate filaments (IFs) is one of the hallmarks of transdifferentiation of hepatic stellate cells into myofibroblast-like cells. These desmin-enriched myofibroblast-like cells are the major sources of fibrotic extracellular matrix in chronically diseased liver. Myofibroblast-like cells are also involved in the contraction of sinusoids, which leads to increased intrahepatic pressure and portal hypertension. To address the requirements for the formation of desmin-containing IFs both in quiescent and in transdifferentiated stellate cells, we used mice deficient for glial fibrillary acidic protein (GFAP) and/or vimentin, which are additional IF proteins present in stellate cells. In this study, we show that desmin cannot form full-length bundles of IFs in the absence of both GFAP and vimentin. Quiescent and transdifferentiated GFAP(-/-)vim(-/-) stellate cells are devoid of normal bundles of IFs. Instead, they exhibit only residual IF bundles restricted to subcortical cytoplasm, although these cells contain equal desmin mRNA and protein levels as wild-type cells. The absence of vimentin alone restricts formation of desmin-containing IF bundles to the perinuclear region, while both the distal processes in quiescent stellate cells and the subcortical zone in myofibroblast-like cells remain free of desmin-containing IF bundles. The absence of GFAP alone does not interfere with the formation of desmin-containing IFs. Thus, to form normal IFs in stellate cells, desmin is required to partnerize with vimentin. In addition, these mouse models will prove to be instrumental in addressing the role of IFs in the process of stellate cell transdifferentiation.

Identification of a 428-kb homozygously deleted region disrupting the SEZ6L gene at 22q12.1 in a lung cancer cell line

Frequent allelic losses on chromosome 22q in small cell lung carcinomas (SCLCs) and advanced non-small cell lung carcinomas indicate the presence of tumor suppressor gene(s) on this chromosome arm. We detected a homozygous deletion at 22q12.1 in a SCLC cell line, Lu24. Cloning of the breakpoints of the Lu24 deletion revealed that the deletion was interstitial and 428, 131 bp in size. The deleted region contained the SEZ6L (Seizure 6-like) gene, whose structure had been partially determined by the chromosome 22 sequencing project. We determined the full length cDNA sequence for the SEZ6L gene based on the genomic sequence for the SEZ6L locus using the GENSCAN program and the RT - PCR method. The deduced SEZ6L protein was a transmembrane protein of 1024 amino acids with multiple domains involved in protein - protein interaction and signal transduction. SEZ6L expression was detected in a variety of human tissues, including lung, while its expression was detected in 14 (30%) of 46 lung cancer cell lines examined. Missense mutations were detected in three (7%) of the 46 cell lines, and a 1 bp deletion in the polypyrimidine tract preceding exon 4 was detected in one (2%) of 46 primary lung cancers. Therefore, it is possible that genetic and/or epigenetic SEZ6L alterations are involved in the development and/or progression in a subset of lung cancer, although functional analysis of the SEZ6L gene as well as molecular analysis of other genes in the homozygously deleted region is necessary to understand the pathogenetic significance of 22q deletions in human lung carcinogenesis.

Altered expression of the ERM proteins in lung adenocarcinoma

Radixin is a member of the ERM (ezrin/radixin/moesin) protein family that is proposed to function as a membrane-cytoskeletal linker. Using differential display analysis, we have identified radixin as a gene down-regulated in primary lung adenocarcinoma. Real-time quantitative reverse transcription polymerase chain reaction confirmed that radixin mRNA was decreased, both in 10 early-stage bronchioloalveolar carcinomas and in 16 invasive lung adenocarcinomas, by 69% (p = 0.0002) and 82% (p < 0.0001), respectively, compared with 9 nontumor lung tissues. Similarly, moesin and ezrin mRNA levels were reduced in lung adenocarcinoma. Immunohistochemistry confirmed that cancer cells expressed very little radixin and moesin, whereas non-neoplastic alveolar and bronchiolar epithelial cells, and endothelial cells, including those within the tumor stroma, were consistently positive for these two proteins. Ezrin was localized in the apical surface of non-neoplastic bronchiolar and alveolar epithelial cells and, in contrast to radixin and moesin, the majority of tumor cells retained expression of ezrin. Localization of ezrin was altered in a significant proportion of tumor cells: whereas tumor cells forming lumina displayed membranous staining on the apical side, tumor cells with disorganized structures were either negative or diffusely positive for ezrin in the cytoplasm. Furthermore, a fraction of tumor cells invading the stroma in a scattered manner were strongly positive for ezrin. In conclusion, expression of radixin and moesin is down-regulated in lung adenocarcinoma, including early-stage bronchioloalveolar carcinoma. An intriguing implication of this finding is that these two genes may function as tumor suppressors in lung adenocarcinoma oncogenesis. Although structurally related to radixin and moesin, ezrin may have a distinct function in tumor-cell invasion.

Differential expression of the LAMB3 and LAMC2 genes between small cell and non-small cell lung carcinomas

To identify genes differentially expressed between small cell lung carcinoma (SCLC) cells and non-SCLC cells, mRNA differential display was applied to 3 SCLC cell lines and 6 non-SCLC cell lines. The LAMB3 gene was identified as being expressed only in non-SCLC cells and not in SCLC cells. The LAMB3 gene encodes the laminin beta3 chain, which is a unique component of laminin-5. Laminin-5 is a heterotrimer protein consisting of the alpha3, beta3, and gamma2 chains, and another unique component of laminin-5 is the gamma2 chain encoded by the LAMC2 gene. RT-PCR analysis of the LAMB3 and LAMC2 genes in 45 lung cancer cell lines revealed that both the LAMB3 and LAMC2 genes were co-expressed in 21 of 32 non-SCLC cell lines (66%) but only in one of 13 SCLC cell lines (8%). Coexpression of the LAMB3 and LAMC2 genes was also observed in all 4 cases of primary non-SCLC cells examined but not in the corresponding non-cancerous lung cells. Since alpha6beta4 integrin, the specific laminin-5 binding receptor, is known to be expressed only in non-SCLC cells and not in SCLC cells, it was indicated that laminin-5 is a critical microenvironmental factor for the growth of non-SCLC cells but not of SCLC cells. The differences in the expression of integrins and laminins would be critical factors to distinguish SCLC and non-SCLC cells, and such differences might be associated with the unique biological properties of SCLC cells, including metastatic potential and drug sensitivity.

Lung carcinoma with polypoid growth in the main pulmonary artery: report of two cases

Invasion into the lumen of the main pulmonary artery is an uncommon mode of extension in lung carcinoma and its prognostic significance remains unclear. We describe here two resected cases of lung carcinoma that showed such a rare tumor spread. Although a preoperative evaluation, such as angiography or perfusion scan of the lung, had shown a significant decrease in circulation, we could not diagnose the intraluminal tumor growth preoperatively. Pneumonectomy was finally needed to perform a curative operation. The tumors were centrally located and showed polypoid growth in the main pulmonary artery. Postoperative pathological examination revealed the tumors to be adenosquamous carcinoma of the lung in both cases. No intrapulmonary metastases were detected. One patient is doing well with no signs of recurrence after a follow-up period of 10 years. Although intra-arterial polypoid growth of lung carcinoma is extremely rare, such tumor extension should be considered preoperatively to perform a curative surgical resection, especially when the tumor is centrally located. While arterial invasion is generally an ominous prognostic factor, curative surgical resection would offer a good prognosis, even for lung carcinoma invading the main pulmonary arterial trunk.

MSSP, a protein binding to an origin of replication in the c-myc gene, interacts with a catalytic subunit of DNA polymerase alpha and stimulates its polymerase activity

MSSP has been identified as a protein that binds to both single- and double-stranded sequences of a putative DNA replication origin sequence in the human c-myc gene. MSSP possesses versatile functions, including stimulation of DNA replication, transcriptional regulation, apoptosis induction, and cell transformation coordinated by c-Myc. MSSP contains two RNP domains, RNP1-A and RNP1-B, both of which are necessary for all of the functions of MSSP. In this study, we found that MSSP binds to the N-terminal region of a catalytic subunit of a human DNA polymerase alpha via its RNP domains both in vitro and in human cells. Furthermore, MSSP was released from the putative DNA replication origin of the c-myc gene after it complexed with DNA polymerase alpha, and MSSP stimulated DNA polymerase activity in vitro.