PRMT1 Sustains De Novo Fatty Acid Synthesis by Methylating PHGDH to Drive Chemoresistance in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) chemoresistance hampers the ability to effectively treat patients. Identification of mechanisms driving chemoresistance can lead to strategies to improve treatment. Here, we revealed that protein arginine methyltransferase-1 (PRMT1) simultaneously methylates D-3-phosphoglycerate dehydrogenase (PHGDH), a critical enzyme in serine synthesis, and the glycolytic enzymes PFKFB3 and PKM2 in TNBC cells. 13C metabolic flux analyses showed that PRMT1-dependent methylation of these three enzymes diverts glucose toward intermediates in the serine-synthesizing and serine/glycine cleavage pathways, thereby accelerating the production of methyl donors in TNBC cells. Mechanistically, PRMT1-dependent methylation of PHGDH at R54 or R20 activated its enzymatic activity by stabilizing 3-phosphoglycerate binding and suppressing polyubiquitination. PRMT1-mediated PHGDH methylation drove chemoresistance independently of glutathione synthesis. Rather, activation of the serine synthesis pathway supplied α-ketoglutarate and citrate to increase palmitate levels through activation of fatty acid synthase (FASN). Increased palmitate induced protein S-palmitoylation of PHGDH and FASN to further enhance fatty acid synthesis in a PRMT1-dependent manner. Loss of PRMT1 or pharmacologic inhibition of FASN or protein S-palmitoyltransferase reversed chemoresistance in TNBC. Furthermore, IHC coupled with imaging MS in clinical TNBC specimens substantiated that PRMT1-mediated methylation of PHGDH, PFKFB3, and PKM2 correlates with chemoresistance and that metabolites required for methylation and fatty acid synthesis are enriched in TNBC. Together, these results suggest that enhanced de novo fatty acid synthesis mediated by coordinated protein arginine methylation and protein S-palmitoylation is a therapeutic target for overcoming chemoresistance in TNBC.

SIGNIFICANCE

PRMT1 promotes chemoresistance in TNBC by methylating metabolic enzymes PFKFB3, PKM2, and PHGDH to augment de novo fatty acid synthesis, indicating that targeting this axis is a potential treatment strategy.

A shift in glutamine nitrogen metabolism contributes to the malignant progression of cancer

Glucose metabolism is remodeled in cancer, but the global pattern of cancer-specific metabolic changes remains unclear. Here we show, using the comprehensive measurement of metabolic enzymes by large-scale targeted proteomics, that the metabolism both carbon and nitrogen is altered during the malignant progression of cancer. The fate of glutamine nitrogen is shifted from the anaplerotic pathway into the TCA cycle to nucleotide biosynthesis, with this shift being controlled by glutaminase (GLS1) and phosphoribosyl pyrophosphate amidotransferase (PPAT). Interventions to reduce the PPAT/GLS1 ratio suppresses tumor growth of many types of cancer. A meta-analysis reveals that PPAT shows the strongest correlation with malignancy among all metabolic enzymes, in particular in neuroendocrine cancer including small cell lung cancer (SCLC). PPAT depletion suppresses the growth of SCLC lines. A shift in glutamine fate may thus be required for malignant progression of cancer, with modulation of nitrogen metabolism being a potential approach to SCLC treatment.

Glucose metabolism is known to be dysregulated in cancer. Here, the authors show that glutamine nitrogen is also affected in cancer and demonstrate that glutaminase 1 and phosphoribosyl pyrophosphate amidotransferase are the key enzymes that control this metabolic switch.

Proteome-wide identification of ubiquitylation sites by conjugation of engineered lysine-less ubiquitin

Ubiquitin conjugation (ubiquitylation) plays important roles not only in protein degradation but also in many other cellular functions. However, the sites of proteins that are targeted for such modification have remained poorly characterized at the proteomic level. We have now developed a method for the efficient identification of ubiquitylation sites in target proteins with the use of an engineered form of ubiquitin (K0-Ub), in which all seven lysine residues are replaced with arginine. K0-Ub is covalently attached to lysine residues of target proteins via an isopeptide bond, but further formation of a polyubiquitin chain does not occur on K0-Ub. We identified a total of 1392 ubiquitylation sites of 794 proteins from HEK293T cells. Profiling of ubiquitylation sites indicated that the sequences surrounding lysine residues targeted for ubiquitin conjugation do not share a common motif or structural feature. Furthermore, we identified a critical ubiquitylation site of the cyclin-dependent kinase inhibitor p27(Kip1). Mutation of this site thus inhibited ubiquitylation of and stabilized p27(Kip1), suggesting that this lysine residue is the target site of p27(Kip1) for ubiquitin conjugation in vivo. In conclusion, our method based on K0-Ub is a powerful tool for proteome-wide identification of ubiquitylation sites of target proteins.

Alteration of intra-pancreatic target-organ specificity by abrogation of Aire in NOD mice

Factors that determine the spectrum of target organs involved in autoimmune destruction are poorly understood. Although loss of function of autoimmune regulator (AIRE) in thymic epithelial cells is responsible for autoimmunity, the pathogenic roles of AIRE in regulating target-organ specificity remain elusive. In order to gain insight into this issue, we have established NOD mice, an animal model of type 1 diabetes caused by autoimmune attack against beta cell islets, in which Aire has been abrogated. Remarkably, acinar cells rather than beta cell islets were the major targets of autoimmune destruction in Aire-deficient NOD mice, and this alteration of intra-pancreatic target-organ specificity was associated with production of autoantibody against pancreas-specific protein disulfide isomerase (PDIp), an antigen expressed predominantly by acinar cells. Consistent with this pathological change, the animals were resistant to the development of diabetes. The results suggest that Aire not only is critical for the control of self-tolerance but is also a strong modifier of target-organ specificity through regulation of T cell repertoire diversification. We also demonstrated that transcriptional expression of PDIp was retained in the Aire-deficient NOD thymus, further supporting the concept that Aire may regulate the survival of autoreactive T cells beyond transcriptional control of self-protein expression in the thymus.

Essential role of IkappaB kinase alpha in thymic organogenesis required for the establishment of self-tolerance

IkappaB kinase (IKK) alpha exhibits diverse biological activities through protein kinase-dependent and -independent functions, the former mediated predominantly through a noncanonical NF-kappaB activation pathway. The in vivo function of IKKalpha, however, still remains elusive. Because a natural strain of mice with mutant NF-kappaB-inducing kinase (NIK) manifests autoimmunity as a result of disorganized thymic structure with abnormal expression of Rel proteins in the thymic stroma, we speculated that the NIK-IKKalpha axis might constitute an essential step in the thymic organogenesis that is required for the establishment of self-tolerance. An autoimmune disease phenotype was induced in athymic nude mice by grafting embryonic thymus from IKKalpha-deficient mice. The thymic microenvironment that caused autoimmunity in an IKKalpha-dependent manner was associated with defective processing of NF-kappaB2, resulting in the impaired development of thymic epithelial cells. Thus, our results demonstrate a novel function for IKKalpha in thymic organogenesis for the establishment of central tolerance that depends on its protein kinase activity in cooperation with NIK.

Subcellular expression of autoimmune regulator is organized in a spatiotemporal manner

Autoimmune regulator (AIRE) is responsible for the development of organ-specific autoimmune disease in a monogenic fashion. Rare and low levels of tissue expression together with the lack of AIRE-expressing cell lines have hampered a detailed analysis of the molecular dynamics of AIRE. Here we have established cell lines stably transfected with AIRE and studied the regulatory mechanisms for its subcellular expression. We found that nuclear body (NB) formation by AIRE was dependent on the cell cycle. Biochemical fractionation revealed that a significant proportion of AIRE is associated with the nuclear matrix, which directs the functional domains of chromatin to provide sites for gene regulation. Upon proteasome inhibition, AIRE NBs were increased with concomitant reduced expression in the cytoplasm, suggesting that subcellular targeting of AIRE is regulated by a ubiquitin-proteasome pathway. We also found that AIRE NBs compete for cAMP-response element-binding protein-binding protein/p300, a common coactivator of transcription, with the promyelocytic leukemia gene product. These results suggest that the transcriptional regulating activities of AIRE within a cell are controlled and organized in a spatiotemporal manner.

Glucose-6-phosphate dehydrogenase in rat lung alveolar epithelial cells. An ultrastructural enzyme-cytochemical study

Glucose-6-phosphate dehydrogenase (G6PD) is the key enzyme of the pentose phosphate pathway in carbohydrate metabolism, and it plays an important role in cell proliferation and antioxidant regulation within cells in various organs. Although marked cell proliferation and oxidant/antioxidant metabolism occur in lung alveolar epithelial cells, definite data has been lacking as to whether cytochemically detectable G6PD is present in alveolar epithelial cells. The distribution pattern of G6PD within these cells, if it is present, is also unknown. The purpose of the present study was to investigate the subcellular localization of G6PD in alveolar cells in the rat lung using a newly-developed enzyme-cytochemistry (copper-ferrocyanide) method. Type I cells and stromal endothelia and fibroblasts showed no activities. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of type II alveolar epithelial cells. The cytochemical controls ensured specific detection of enzyme activity. This enzyme may play a role in airway defense by delivering substances for cell proliferation and antioxidant forces, thus maintaining the airway architecture.

Preferential interaction of TIP120A with Cul1 that is not modified by NEDD8 and not associated with Skp1

The SCF complex, which consists of the invariable components Skp1, Cul1, and Rbx1 as well as a variable F-box protein, functions as an E3 ubiquitin ligase. The mechanism by which the activity of this complex is regulated, however, has been unclear. The application of tandem affinity purification has now resulted in the identification of a novel Cul1-binding protein: TATA-binding protein-interacting protein 120A (TIP120A, also called CAND1). Immunoprecipitation, immunoblot, and immunofluorescence analyses with mammalian cells revealed that TIP120A physically associates with Cul1 in the nucleus and that this interaction is mediated by a central region of Cul1 distinct from its binding sites for Skp1 and Rbx1. Furthermore, TIP120A was shown to interact selectively with Cul1 that is not modified by NEDD8. The Cul1-TIP120A complex does not include Skp1, raising the possibility that TIP120A competes with Skp1 for binding to Cul1. These observations thus suggest that TIP120A may function as a negative regulator of the SCF complex by binding to nonneddylated Cul1 and thereby preventing assembly of this ubiquitin ligase.

Expression and function of the ST2 gene in a murine model of allergic airway inflammation

BACKGROUND

We have recently reported that soluble ST2 protein levels are elevated in the sera of patients with asthma, and correlate well with the severity of asthma exacerbation. However, the role, function, and kinetics of soluble ST2 expression in asthma remain unclear.

OBJECTIVE

The objective of the present study was to clarify the function and kinetics of soluble murine (m) ST2 expression in a murine asthma model.

METHODS

We analyzed the kinetics of gene and protein expression of mST2 in sera or lung tissue after allergen (ovalbumin; OVA) challenge in a murine model of allergic airway inflammation, the effects of mST2 protein on OVA-induced Th2 cytokine production in vitro from splenocytes of sensitized mice, and the effects of soluble mST2 on Th2-dependent allergic airway inflammation by in vivo gene transfer of mST2.

RESULTS

Serum mST2 protein levels increased to the maximal level 3 h after the allergen challenge, before serum IL-5 levels peaked. The mRNA expression of mST2 in lung tissue was induced after the allergen challenge, while that in the spleen was constitutively detected. Furthermore, pre-treatment with mST2 protein significantly inhibited the production of IL-4 and IL-5, but not IFN-gamma, from OVA-stimulated splenocytes in vitro, and intravenous mST2 gene transfer resulted in a drastic reduction in the number of eosinophils and in the levels of IL-4 and IL-5 in bronchoalveolar lavage fluid, compared with those in response to transfer of non-coding plasmid vector or of lipid alone.

CONCLUSION

These results suggest that increases in endogenous mST2 protein after allergen exposure may modulate Th2-mediated airway inflammation, and that in vivo gene transfer of mST2 can be applicable to use in a novel immunotherapy for allergic diseases.

Degradation of p27(Kip1) at the G(0)-G(1) transition mediated by a Skp2-independent ubiquitination pathway

Targeting of the cyclin-dependent kinase inhibitor p27(Kip1) for proteolysis has been thought to be mediated by Skp2, the F-box protein component of an SCF ubiquitin ligase complex. Degradation of p27(Kip1) at the G(0)-G(1) transition of the cell cycle has now been shown to proceed normally in Skp2(-/-) lymphocytes, whereas p27(Kip1) proteolysis during S-G(2) phases is impaired in these Skp2-deficient cells. Degradation of p27(Kip1) at the G(0)-G(1) transition was blocked by lactacystin, a specific proteasome inhibitor, suggesting that it is mediated by the ubiquitin-proteasome pathway. The first cell cycle of stimulated Skp2(-/-) lymphocytes appeared normal, but the second cycle was markedly inhibited, presumably as a result of p27(Kip1) accumulation during S-G(2) phases of the first cell cycle. Polyubiquitination of p27(Kip1) in the nucleus is dependent on Skp2 and phosphorylation of p27(Kip1) on threonine 187. However, polyubiquitination activity was also detected in the cytoplasm of Skp2(-/-) cells, even with a threonine 187 --> alanine mutant of p27(Kip1) as substrate. These results suggest that a polyubiquitination activity in the cytoplasm contributes to the early phase of p27(Kip1) degradation in a Skp2-independent manner, thereby promoting cell cycle progression from G(0) to G(1).

Infection of TT virus in patients with idiopathic pulmonary fibrosis

The precipitating factors of idiopathic pulmonary fibrosis (IPF) have not been elucidated. Recently, a novel DNA virus named TTvirus (TTV) was discovered in a patient with post-transfusion hepatitis of unknown aetiology TTV is a circular, single-stranded DNA virus of 3.8 kB. To evaluate the relationship between TTV and IPF, the sera of 33 patients with IPF were tested for the presence of TTV DNA by semi-nested polymerase chain reaction. TTV DNA was detected in 12 (36.4%) IPF patients. The serum lactate dehydrogenase (LDH) level was significantly higher in the IPF patients withTTV than in those without TTV (802 +/- 121 vs. 530 +/- 49 IU l(-1), p < 0.05). Six (50%) of 12 patients in theTTV DNA-positive group died during the observation period, while only six (28.6%) of 21 patients in theTTV DNA-negative group died. The 3-year-survival rate was significantly lower in the TTV DNA-positive group than in theTTV DNA-negative group (58-3% vs. 95.2%, P <0-02). Replicative intermediate forms of TTV DNA were detected in the lung specimen from a TTV-infected IPF patient. TTV infection influences the disease activityand prognosis of IPF in some cases. Further studies are required to elucidate the clinical significance of TTV in IPF.

Elevated soluble CD26 levels in patients with tuberculous pleurisy

SETTING

Several reports have shown that tuberculous infection elicits a Th1-like immune response with increased levels of IFN-gamma. Recently, expression of CD26 on CD4+ lymphocytes has been shown to correlate with the production of Th1-like cytokines. We therefore hypothesized that CD26 expression might increase in tuberculous pleural effusion, and might thus be a possible marker for detecting tuberculous pleurisy.

OBJECTIVE AND DESIGN

To test this hypothesis, we measured soluble CD26 levels in the serum and pleural fluid of patients with tuberculous pleurisy (TB; n = 13), carcinomatous pleurisy (CA, n = 17), empyema (EM, n = 6), and congestive heart failure (HF, n = 10).

RESULTS

The pleural CD26 levels, but not the serum CD26 levels, in patients with tuberculous pleurisy were significantly higher than those in other groups, and were correlated with levels of adenosine deaminase and interferon-gamma in the tuberculous pleural effusion. Furthermore, when the cut-off value for p-CD26 was set at 544.5 ng/ml, the positive rate for the TB group was significantly higher than that for the CA, EM and HF groups (P < 0.05).

CONCLUSION

These results suggest that elevation of soluble CD26 in pleural fluid is implicated in Th1-like immune response, and may be a useful marker for tuberculous pleurisy.

Elevated soluble ST2 protein levels in sera of patients with asthma with an acute exacerbation

Previous studies have reported that ST2 is preferentially expressed on Th2 cells and plays a critical part in controlling airway inflammation in murine models of asthma. However, the clinical role of ST2 in patients with bronchial asthma remains unclear. In our study, we examined 56 patients with atopic asthma in a nonattack phase and 200 nonatopic normal volunteers for healthy control, and analyzed the relationship of their serum ST2 levels to asthma severity, pulmonary function, and laboratory data. Of the 56 patients with atopic asthma, 30 exhibited asthmatic exacerbation, and their serum ST2 levels were also analyzed. The serum ST2 levels were low, but a statistical difference was found between patients with nonattack asthma and the healthy control group (p < 0.05). We also found a differential rise of serum ST2 level that correlates well with the severity of asthma exacerbation. Furthermore, the serum ST2 levels during asthma exacerbation statistically correlated with the percentage of predicted peak expiratory flow (r = -0.634, p = 0.004) and Pa(CO(2)) (r = 0.516, p = 0.003). These results suggest that soluble human ST2 protein in sera may be related to Th2-mediated allergic inflammation inducing acute exacerbation in patients with atopic asthma.

[Cytokine production by peripheral blood mononuclear cells in bronchial asthma treated with suplatast tosilate]

Supratast tosilate is a newly developed 'anti-allergic' drug and it has been shown to suppress cytokine production by type-2 helper T cells (Th2) in vitro. However, it is unclear whether a similar inhibitory effect on Th2 cytokines production is produced iv vivo. To elucidate the actions of the in vivo mechanisms of this drug, we isolated peripheral blood mononuclear cells (PBMCs) from 10 atopic asthmatics treated with supratast tosilate and investigated the capacity for cytokine production ex vivo. Interleukin (IL)-5 production by PBMCs stimulated with the combination of phorbol myristate acetate and ionomycin were reduced significantly 6 or 12 weeks after the treatment with supratast tosilate. In contrast, no significant reduction was seen in IL-4 or Interferon (IFN)-gamma production. The peripheral blood eosinophil count and weeks, but no significant difference was sees in total IgE levels. Both morning and evening peak expiratory flow were significantly elevated after 6 weeks. These results suggest that supratast tosilate improves the disease status of bronchial asthma through its ability to inhibit the production Th2 cytokines, at least IL-5, in vivo.

Interleukin 12 gene transfer into skin distant from the tumor site elicits antimetastatic effects equivalent to local gene transfer

We have reported that particle-mediated interleukin 12 (IL-12) gene transfer into the skin overlying the local tumor inhibits systemic metastases. To further characterize this effect, we compared the antitumor and antimetastatic effects of IL-12 cDNA delivered at the local tumor site versus at a site distant from the primary tumor, in a spontaneous metastasis model of LLC-F5 tumor. Local IL-12 gene delivery into the skin overlying the intradermal tumor (local IL-12 treatment) on days 7, 9, and 11 after tumor implantation resulted in the most suppression of the growth of the primary LLC-F5 tumor, whereas IL-12 gene transfer into the skin distant from the tumor (distant IL-12 treatment) was less effective. In contrast, both local IL-12 and distant IL-12 treatment, followed by tumor excision, inhibited lung metastases to a similar extent, resulting in significantly extended survival of test mice. The results of in vivo studies using depleting anti-asialo GM1 antibody and anti-CD4/anti-CD8 monoclonal antibodies, or neutralizing anti-interferon gamma (IFN-gamma) monoclonal antibody demonstrated that natural killer (NK) cells, CD8(+) T cells, and IFN-gamma contributed to the antimetastatic effects in both treatment groups. Furthermore, the levels of mRNA expression of vascular endothelial growth factor and matrix methalloproteinase 9 at the tumor microenvironment were suppressed after both local and distant IL-12 treatment. These results suggest that the current particle-mediated IL-12 gene delivery in the spontaneous LLC-F5 metastasis model can confer antimetastatic activities, irrespective of the gene transfection site, via a combination of several mechanisms involving CD8(+) T cells, NK cells, IFN-gamma, and antiangiogenesis.

Serum anti-p53 autoantibodies from patients with idiopathic pulmonary fibrosis associated with lung cancer

Mutations of the tumour suppressor gene p53 lead to accumulation of the mutated p53 protein and subsequent production of antoantibodies against p53 proteins, which are also detected in lung cancer. Lung cancer is frequently associated with idiopathic pulmonary fibrosis (IPF). Therefore, we hypothesized that there might be a relationship between the p53 mutation and high prevalence of lung cancer in IPF. To test this hypothesis, we measured serum p53 antibody levels by an ELISA in various lung diseases including lung cancer (n=98), IPF (n=46; with lung cancer, n=14 and without lung cancer, n=32), pulmonary emphysema (PE, n=23) and healthy controls (HC, n=93). The median values of the serum anti-p53 antibody in each group were 8.78, 9.18, 8.08 and 4.95 for patients with lung cancer, IPF with lung cancer, IPF without lung cancer and PE, respectively, and 2.2 for the healthy control group. The groups of IPF (with and without lung cancer) showed a similar level of median values to the lung cancer group and a tendency for a higher level than the PE group. When the cut-off value was set at 7.7 according to the 95% specificity level for normal control, the incidence of positive anti-p53 antibody was significantly higher in lung cancer (61.2%), IPF with lung cancer (57.1%) and IPF without lung cancer (53.1%) than PE (21.7%). These results suggest that p53 mutations occur frequently and substantially in IPF, resulting in a high prevalence of lung cancer.

Purification and characterization of a basic amino acid-specific peptidase from seeds of jack bean (Canavalia ensiformis)

A peptidase was purified from seeds of Canavalia ensiformis by extraction with water, ammonium sulfate precipitation, and successive chromatographies on DEAE-Toyopearl 650M, butyl-Toyopearl 650M, and G-3000 SW columns. The enzyme has an apparent molecular weight of 41,000. Activity is maximal at pH 9 and 60 degrees C. The enzyme hydrolyzed synthetic substrates at Arg-X and Lys-X bonds more rapidly than bovine trypsin did, and did not cleave protein or ester substrates. The enzyme was inhibited by alkylamines and several serine protease inhibitors such as diisopropylfluorophosphate, chymostatin, leupeptin, and benzamidine. Cysteine protease-, metalloprotease-, and proteinous trypsin inhibitors were ineffective. Inhibition by alkylamines was dependent on length of the alkyl chains. From the substrate specificity and susceptibility to chemicals, the enzyme is a unique peptidase with trypsin-like specificity.

Primary structure and autoproteolysis of brevilysin H6 from the venom of Gloydius halys brevicaudus

The complete amino acid sequence of brevilysin H6 (H6), a zinc-protease isolated from Gloydius halys brevicaudus venom, was determined by a manual Edman degradation method. H6 has an amino-terminal pyroglutamic acid and consists of a total of 419 residues. An N-linked sugar chain is attached at Asn-181. The molecule is composed of three domains (metalloprotease, disintegrin-like and cysteine-rich domains), as commonly found in other high molecular mass metalloproteases from snake venoms. In the absence of calcium ions, H6 is autocatalytically degraded with a half-life of 47 min to give 29 and 45 kDa fragments, which correspond to residues 208-419 and 99-419 of H6, respectively. Thus, the autoproteolysis seemed to start from the cleavage of either the Leu(98)-Leu(99) or Asp(207)-Ile(208) bond. Calcium ions suppressed both the formation of the 45 kDa fragment and the rate of autoproteolysis. Calcium ions also contributed to the stability of H6 against pH, heating, urea and cysteine. More than twenty-five peptide bonds adjacent to hydrophobic residues in the metalloprotease domain were progressively cleaved during the autoproteolysis.

Construction of ELISA system to quantify human ST2 protein in sera of patients

The human ST2 gene can be specifically induced by growth stimulation in fibroblastic cells, and can also be induced by antigen stimulation in Th2 cells. The gene encodes a soluble secreted protein, ST2, and a transmembrane protein, ST2L, which are closely related to the interleukin-1 receptor. To gain insight into the biological roles of the ST2 gene, three monoclonal antibodies (MAbs) against human ST2 gene products were obtained. To obtain these antibodies, immunization was carried out using two different immunogens: purified soluble human ST2 protein (hST2), and COS7 cells, which express the extracellular portion of human ST2L. 2A5 and FB9 MAbs were derived from the immunization with soluble hST2, and HB12 was derived from the COS7 cell immunization. All three antibodies were shown to detect native forms of the human ST2 gene products by immunoprecipitation, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). In the competitive ELISA using biotinylated and nonlabelled MAbs, neither FB9 nor HB12 affected the binding of 2A5 to ST2 gene products. Based on this result, we constructed a sandwich ELISA system using 2A5 and FB9 to measure the concentration of soluble hST2 in sera. The ELISA, combined with the flow cytometry using these antibodies, will be a useful tool for elucidating the functions of human ST2 gene products in individuals.

Synergistic inhibition of tumor growth in a murine mammary adenocarcinoma model by combinational gene therapy using IL-12, pro-IL-18, and IL-1beta converting enzyme cDNA

We report here that a cancer gene therapy protocol using a combination of IL-12, pro-IL-18, and IL-1beta converting enzyme (ICE) cDNA expression vectors simultaneously delivered via gene gun can significantly augment antitumor effects, evidently by generating increased levels of bioactive IL-18 and consequently IFN-gamma. First, we compared the levels of IFN-gamma secreted by mouse splenocytes stimulated with tumor cells transfected with various test genes, including IL-12 alone; pro-IL-18 alone; pro-IL-18 and ICE; IL-12 and pro-IL-18; and IL-12, pro-IL-18, and ICE. Among these treatments, the combination of IL-12, pro-IL-18, and ICE cDNA resulted in the highest level of IFN-gamma production from splenocytes in vitro, and similar results were obtained when these same treatments were delivered to the skin of a mouse by gene gun and IFN-gamma levels were measured at the skin transfection site in vivo. Furthermore, the triple gene combinatorial gene therapy protocol was the most effective among all tested groups at suppressing the growth of TS/A (murine mammary adenocarcinoma) tumors previously implanted intradermally at the skin site receiving DNA transfer by gene gun on days 6, 8, 10, and 12 after tumor implantation. Fifty percent of mice treated with the combined three-gene protocol underwent complete tumor regression. In vivo depletion experiments showed that this antitumor effect was CD8(+) T cell-mediated and partially IFN-gamma-dependent. These results suggest that a combinatorial gene therapy protocol using a mixture of IL-12, pro-IL-18, and ICE cDNAs can confer potent antitumor activities against established TS/A tumors via cytotoxic CD8(+) T cells and IFN-gamma-dependent pathways.

Particle-mediated gene transfer of murine interleukin-12 cDNA suppresses the growth of Lewis lung carcinoma

We evaluated the effectiveness of the Helios gene gun system, a recently developed, commercially available gene gun device. Following skin transfection with beta-galactosidase or interleukin-12 cDNA using the gene gun, beta-galactosidase expression was detected exclusively in the epidermal cell layer, and transgene expression of IL-12 cDNA was maximal 2 days post-transfection and remained detectable for at least 5 additional days. Furthermore, particle-mediated delivery of IL-12 cDNA into epidermal cells overlying an intradermal tumor resulted in a significant suppression of tumor growth of Lewis lung carcinoma. Appreciable levels of IFN-gamma production were readily detected at the skin transfection site, and were induced from splenocytes and lymph node cells in the IL-12 treated mice. These results show that in vivo delivery of IL-12 cDNA into skin by the Helios gene gun device can have a useful routine application for cancer therapy research.

Ussuristatin 2, a novel KGD-bearing disintegrin from Agkistrodon ussuriensis venom

Two platelet aggregation inhibitors, ussuristatin 1 (US-1) and 2 (US-2), were newly isolated from the venom of Chinese viper (Agkistrodon ussuriensis) by SP-Toyopearl 650M column chromatography and reverse-phase HPLC. The Mrs of these polypeptides were estimated to be about 8,000 by SDS-PAGE. Analytical gel filtration revealed that US-2 exists as a dimer. Both polypeptides comprised 71 amino acids, whose sequences showed high similarities to those of other disintegrins. US-1 had a typical Arg-Gly-Asp (RGD) sequence, which is responsible for blocking the binding of fibrinogen to the receptor. In US-2, the corresponding sequence was Lys-Gly-Asp (KGD). US-1 strongly suppressed platelet aggregation induced by ADP, collagen, thrombin, and epinephrine with IC50 = 17-33 nM. US-2 also inhibited the platelet aggregation, but the IC50s were about ten times higher. US-1 also dose-dependently inhibited the adhesion of human melanoma cells to fibrinogen and fibronectin, while US-2 did not inhibit the cell adhesion to fibronectin. This indicates that the KGD-bearing disintegrin is a specific inhibitor for the fibrinogen receptor.

Evaluation of bronchoscopic findings in patients with metastatic pulmonary tumor

To clarify the bronchoscopic findings in metastatic spread to the bronchi, we analyzed the records of 65 cases of metastatic pulmonary disease in which fiberoptic bronchoscopy had been done. Forty-five patients (69.2%) had abnormal bronchoscopic findings. These patients could be divided into three groups, according to bronchoscopic findings and route of metastatic spread to the bronchi: endobronchial metastasis (n=15), bronchial involvement (that is, direct extension to the bronchi from adjacent metastatic foci, n=15), and lymphangitis carcinomatosa (n=15). Breast cancer and colon cancer were common in cases of endobronchial metastasis, and the bronchial tumor often presented as a polypoid or nodular lesion covered with necrotic material. Submucosal swelling with an irregular margin and narrowing of the bronchial lumen were seen in cases of bronchial involvement. In conclusion, each type of primary extrapulmonary tumor is associated with characteristic endobronchial findings of pulmonary metastases such as endobronchial metastasis and bronchial involvement, which should be discriminated if possible, because of their different metastatic process.

Multiple pulmonary metastases with cavitation from gallbladder cancer

We report a rare case of multiple pulmonary metastases with cavitation from gallbladder cancer. A 77-year-old woman was admitted to our hospital complaining of productive cough and exertional dyspnea. Chest X-ray film showed multiple nodular shadows with some cavitation. Computed tomography showed multiple cavities, up to 2 cm in diameter, as well as nodules, in bilateral lung fields. Under a survey of primary focus, the ultrasonographic test of the abdomen revealed a hypoechoic mass in the hepatic hilum. The patient died of respiratory failure. Autopsy findings revealed that that multiple lung tumors had metastasized from papillary adenocarcinoma of the gallbladder and that cavitation of the lung was formed by bronchioloectasis.

[Clinico-pathological analysis of interstitial pneumonia associated with collagen vascular disease in patients with lung cancer]

We investigated interstitial pneumonia associated with collagen vascular disease (IP-CVD) in association with lung cancer. Seventy-three cases of IP-CVD were included in this study. Nine (12%) of the 73 cases were associated with lung cancer, one of which had double lung cancers. The histological types of the cancers were adenocarcinoma (5 cases), epidermoid carcinoma (2 cases), small cell carcinoma, large cell carcinoma and large cell neuroendocrine carcinoma (one case each). The lesions were located in the central or peripheral lung in 3 and 7 of the ten cancers, respectively. Of the seven cases diagnosed as having IP-CVD followed by lung cancer, five had stage I disease, and one each of the remaining two cases was in stage IIIA and stage IV. Six of the seven peripheral cancer lesions which were resected or autopsied could be analyzed with regard to the topographical relationship between the primary site and fibrotic lesions. Only three cancers were encased by or in close proximity to, honeycomb lung, although most of the lung cancers arose in relation to fibrotic lesions. Moreover, the acute exacerbation of IP-CVD after operation or chemotherapy without thoracic irradiation should be monitored carefully.

[Diffuse panbronchioliltis associated with bullous pemphigoid]

A 64-year-old woman complained of multiple blisters in 1990. She had had a productive cough since 1975. Immunofluorescence study of a specimen obtained from a skin biopsy showed staining in a linear pattern for both IgG and C3 in the epithelial basement membrane zone (BMZ) of the dermal-epidermal junction, and a high titer of anti-BMZ antibody. These findings led to the diagnosis of bullous pemphigoid. Corticosteroid therapy was started, and resulted in some stabilization of the skin lesion. Exertional dyspnea and a productive cough developed gradually, and the patient was referred to our department in 1992. Chest X-ray film and CT findings revealed a diffuse granular shadow and bronchiectatic change, predominantly in the lower lung fields. Laboratory tests showed a high titer of cold hemagglutinin and a high level of serum immunoglobulin A. Pulmonary function tests showed a combined destructive-restrictive defect and hypoxemia (PaO2 = 58.5 Torr). From these findings diffuse panbronchiolitis was diagnosed. A low dose of erythromycin alleviated the patient's pulmonary symptoms and improved the chest radiographic findings.

[A case of lung cancer with cryptococcal infection in resected lymph nodes]

A 68-year-old female was admitted because of an abnormal shadow on chest X-ray film. Chest CT showed a nodular shadow in right S3a. Right upper lobectomy with mediastinal lymph node resection was performed under a diagnosis of lung cancer made by TBLB. Pathological examination of the resected lung revealed well differentiated adenocarcinoma. In addition, examination of the resected lymph nodes showed granulomas, some of which contained numerous cryptococci and showed central caseous necrosis, and others showed non-caseating epithelioid cell granulomas suggesting sarcoid reaction. No cryptococcal infection was found in the resected lung. Mediastinal lymph node involvement of cryptococcus in this case was considered to be the lymph node component of the primary pulmonary complex of cryptococcosis. Such a primary complex was demonstrated in 1% of the cases of cryptococcosis in previous reports.

[A case of intrapulmonary neurilemmoma]

A 33-year-old man was admitted to our hospital because of an abnormal shadow on chest X-ray film. Chest X-ray film and chest CT showed a round tumor in the left infrahilar area. Bronchoscopic findings revealed narrowing of left B5 and B8, with extraluminal compression. A preoperative diagnosis was not obtained and tumor resection was performed. The tumor was located in the parenchyma of left S8. Histological examination showed nuclear palisading and loosely textured spindle cells within myxomatous tissue, compatible with neurilemoma. Intrapulmonary neurilemoma is extremely rare and only 23 cases have been previously reported in Japan.