[Hair Testing for Drugs in the Field of Forensics].

Hair testing for drugs has been used extensively in the field of forensics since the 1990s as a means of obtaining firm evidence of drug ingestion. In addition to its longer detection windows, hair is the only specimen that can provide chronological information on individual drug use. Illicit drugs and hypnotics account for the majority of substances involved in crimes; they are usually analyzed to prove an addictive use or an exposure to drugs in drug-facilitated crimes. The mechanism of drug incorporation into hair has been intensively investigated to properly interpret the results of hair analysis. However, the exact mechanism remains under much discussion, despite the growing application of hair tests. Recently, the authors have applied matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) imaging and sectional hair analysis of 1-mm segments using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for single-strand hair, to investigate the incorporation pathways of drugs into hair. Time-course changes in drug distribution along single-strand hair suggest that the incorporation of drugs occurs in two regions of the hair root, the hair bulb and the upper part of hair root, and suggest that incorporation from the hair bulb continues for about 2 weeks. Distribution profiles of different drugs in hair additionally revealed that the main incorporation pathway varies (i.e., via the hair bulb or the upper part of hair root) depending on the properties of the drug/metabolite. These findings should be taken into account upon discussing individual drug-use history based on the results of hair analysis.

Identification and Characterization of a Novel NADPH Oxidase 1 (Nox1) Inhibitor That Suppresses Proliferation of Colon and Stomach Cancer Cells.

Reactive oxygen species (ROS) generated by reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox)1 mediate cellular signalings involved in normal physiological processes, and aberrant control of Nox1 has been implicated in the pathogenesis of various diseases. Therefore, Nox1 could have great potential as a therapeutic target. Here, we identified a novel Nox1 inhibitor, NOS31 secreted from Stretomyces sp. and analyzed its chemical structure. Furthermore, NOS31 was found to selectively inhibit Nox1-mediated ROS generation, with only a marginal effect on other Nox isoforms (Nox2-5) and no ROS scavenging activity. This compound blocked both Nox organizer 1 (NOXO1)/Nox activator 1 (NOXA1)-dependent and phorbol 12-myristate 13-acetate-stimulated Nox1-mediated ROS production in colon cancer cells. NOS31 inhibited the proliferation of several colon carcinoma and gastric cancer cell lines that upregulate the Nox1 system, whereas it had no appreciable effect on normal cells with low levels of Nox1. The finding suggests that NOS31 is a unique, potent Nox1 inhibitor of microbial origin and raises its possibility as a therapeutic agent for inhibiting gastrointestinal cancer cell growth.

The ROS-generating oxidase Nox1 is required for epithelial restitution following colitis.

Accumulating evidence suggests that reactive oxygen species (ROS) generated by endogenous metabolic enzymes are involved in a variety of intracellular mechanisms. In particular, superoxide-generating NADPH oxidase (Nox) 1 is highly expressed in the colon and has been implicated in physiological and pathophysiological states of colon tissues. However, its role in tissue repair following colitis has not been fully elucidated. Our study using experimental colitis in mice showed that repair of the mucosal layer did not occur in Nox1-deficient mice following dextran sulfate sodium-induced colitis. This was accompanied by inhibition of proliferation, cell survival, migration, and terminal differentiation (generation of goblet cells) of crypt progenitor cells, as determined by histochemical analyses. Furthermore, Nox1 expression as well as ROS production in the colon crypt was increased during the repair process, and Nox1 deficiency suppressed these events. The results suggest that Nox1 promotes colon mucosal wound repair by sustaining the bioactivity of crypt progenitor cells and plays a crucial role in the epithelial restitution in the case of damage associated with colitis.

Superoxide-Generating Nox5α Is Functionally Required for the Human T-Cell Leukemia Virus Type 1-Induced Cell Transformation Phenotype.

UNLABELLED: Human T-cell leukemia virus type 1 (HTLV-1) is associated with adult T-cell leukemia (ATL) and transforms T cells in vitro. To our knowledge, the functional role of reactive oxygen species (ROS)-generating NADPH oxidase 5 (Nox5) in HTLV-1 transformation remains undefined. Here, we found that Nox5α expression was upregulated in 88% of 17 ATL patient samples but not in normal peripheral blood T cells. Upregulation of the Nox5α variant was transcriptionally sustained by the constitutive Janus family tyrosine kinase (Jak)-STAT5 signaling pathway in interleukin-2 (IL-2)-independent HTLV-1-transformed cell lines, including MT1 and MT2, whereas it was transiently induced by the IL-2-triggered Jak-STAT5 axis in uninfected T cells. A Nox inhibitor, diphenylene iodonium, and antioxidants such as N-acetyl cysteine blocked proliferation of MT1 and MT2 cells. Ablation of Nox5α by small interfering RNAs abrogated ROS production, inhibited cellular activities, including proliferation, migration, and survival, and suppressed tumorigenicity in immunodeficient NOG mice. The findings suggest that Nox5α is a key molecule for redox-signal-mediated maintenance of the HTLV-1 transformation phenotype and could be a potential molecular target for therapeutic intervention in cancer development. IMPORTANCE: HTLV-1 is the first human oncogenic retrovirus shown to be associated with ATL. Despite the extensive study over the years, the mechanism underlying HTLV-1-induced cell transformation is not fully understood. In this study, we addressed the expression and function of ROS-generating Nox family genes in HTLV-1-transformed cells. Our report provides the first evidence that the upregulated expression of Nox5α is associated with the pathological state of ATL peripheral blood mononuclear cells and that Nox5α is an integral component of the Jak-STAT5 signaling pathway in HTLV-1-transformed T cells. Nox5α-derived ROS are critically involved in the regulation of cellular activities, including proliferation, migration, survival, and tumorigenicity, in HTLV-1-transformed cells. These results indicate that Nox5α-derived ROS are functionally required for maintenance of the HTLV-1 transformation phenotype. The finding provides new insight into the redox-dependent mechanism of HTLV-1 transformation and raises an intriguing possibility that Nox5α serves as a potential molecular target to treat HTLV-1-related leukemia.

Nox4 redox regulation of PTP1B contributes to the proliferation and migration of glioblastoma cells by modulating tyrosine phosphorylation of coronin-1C.

Glioblastoma multiforme is a common primary brain tumor in adults and one of the most devastating human cancers. Reactive oxygen species (ROS) generated by NADPH oxidase (Nox) 4 have recently been a focus of attention in the study of glioblastomas, but the molecular mechanisms underlying the actions of Nox4 remain elusive. In this study, we demonstrated that silencing of Nox4 expression by Nox4-targeted siRNA suppressed cell growth and motility of glioblastoma U87 cells, indicating the involvement of Nox4. Furthermore, Nox4-derived ROS oxidized and inactivated protein tyrosine phosphatase (PTP):1B: PTP1B in its active form downregulates cell proliferation and migration. By affinity purification with the substrate-trapping mutant of PTP1B, tyrosine-phosphorylated coronin-1C was identified as a substrate of PTP1B. Its tyrosine phosphorylation level was suppressed by Nox4 inhibition, suggesting that tyrosine phosphorylation of coronin-1C is regulated by the Nox4-PTP1B pathway. Finally, ablation of coronin-1C attenuated the proliferative and migratory activity of the cells. Collectively, these findings reveal that Nox4-mediated redox regulation of PTP1B serves as a modulator, in part through coronin-1C, of the growth and migration of glioblastoma cells, and provide new insight into the mechanistic aspect of glioblastoma malignancy.

Nox4-derived ROS signaling contributes to TGF-ß-induced epithelial-mesenchymal transition in pancreatic cancer cells.

UNLABELLED: Transforming growth factor (TGF)-ß induces epithelial-mesenchymal transition (EMT) in pancreatic adenocarcinoma. In this study, we investigated how NADPH oxidase (Nox) 4-generated reactive oxygen species (ROS) regulate TGF-ß-induced EMT in pancreatic cancer cells. MATERIALS AND METHODS: Pancreatic cancer cells were transfected with Nox4 siRNAs or PTP1B mutants and subjected to TGF-ß-induced EMT assay. Expression of Nox4, TGF-ß, and N-cadherin was immunohistochemically-examined with patient tumor samples. RESULTS: Treatment of pancreatic cancer cells with TGF-ß induced Nox4 expression, indicating that Nox4 represents a major source for ROS production. The Nox4 inhibitor diphenylene iodonium and Nox4 siRNAs blocked TGF-ß-induced EMT phenotype including morphological changes, augmented migration, and altered expression of E-cadherin and Snail. Furthermore, PTP1B as a redox-sensor for Nox4-derived ROS participated in TGF-ß-promoted EMT. Nox4, TGF-ß, and N-cadherin were up-regulated in tumors from pancreatic cancer patients. CONCLUSIONS: These findings suggest that Nox4-derived ROS, at least in part, transmit TGF-ß-triggered EMT signals through PTP1B in pancreatic cancer.

ROS-generating oxidases Nox1 and Nox4 contribute to oncogenic Ras-induced premature senescence.

Activated oncogenes induce premature cellular senescence, a permanent state of proliferative arrest in primary rodent and human fibroblasts. Recent studies suggest that generation of reactive oxygen species (ROS) is involved in oncogenic Ras-induced premature senescence. However, the signaling mechanism controlling this oxidant-mediated irreversible growth arrest is not fully understood. Here, we show that through the Ras/MEK pathway, Ras oncogene up-regulated the expression of superoxide-generating oxidases, Nox1 in rat REF52 cells and Nox4 in primary human lung TIG-3 cells, leading to an increase in intracellular level of ROS. Ablation of Nox1 and Nox4 by small interfering RNAs (siRNAs) blocked the RasV12 senescent phenotype including ß-galactosidase activity, growth arrest and accumulation of tumor suppressors such as p53 and p16Ink4a. This suggests that Nox-generated ROS transduce senescence signals by activating the p53 and p16Ink4a pathway. Furthermore, Nox1 and Nox4 siRNAs inhibited both Ras-induced DNA damage response and p38MAPK activation, whereas overexpression of Nox1 and Nox4 alone was able to induce senescence. The involvement of Nox1 in Ras-induced senescence was also confirmed with embryonic fibroblasts derived from Nox1 knockout mice. Together, these findings suggest that Nox1- and Nox4-generated ROS play an important role in Ras-induced premature senescence, which may involve DNA damage response and p38MAPK signaling pathways.

Titanium-treated surroundings attenuate psychological stress associated with autonomic nerve regulation in office workers with daily emotional stress.

Housing mice in the presence of small particles of titanium has been shown to reduce stress-responsive behavior via the autonomic nervous system. Here, we examined the effects of nighttime titanium exposure on stress parameters and autonomic nerve activity in office workers with emotional stress. A randomized double-blind, placebo controlled trial was performed in 24 male subjects with desk jobs, who were randomly allocated to spend 5 nights in rooms with or without titanium. The serum concentrations of stress-responsive hormones (cortisol, adrenocorticotropin, and catecholamine) were measured, and profiles of emotional stress were collected to subjectively assess relaxation. Autonomic nerve activity was examined by power spectra analysis of heart rate variability. In psychological tests, factors related to tension (-14.5%, 95% CI=-15.7--2.1), anger (-11.3%, 95% CI=-13.9--0.7), and emotional stress (-28.5%, 95% CI=-30.0--5.3) were significantly decreased by exposure to titanium. The serum level of adrenocorticotropin was gradually elevated throughout the experimental period in the placebo group (day 4, 80.5%, 95% CI=7.1-37.5 vs. before trial) but not the titanium group. Power spectral analysis of R-R interval data showed a significant elevation in the high-frequency power spectral ratio in subjects housed in titanium rooms (days 1-2, 14.3%, 95% CI=4.7-21.9; days 3-4, 26.8%, 95% CI=4.9-38.7; and days 5-6, 24.1%, 95% CI=5.8-34.0 vs. before trial). These results suggest that sleeping in a room containing titanium lowers physiological and psychological stress.

A crucial role for Nox 1 in redox-dependent regulation of Wnt-ß-catenin signaling.

Canonical Wnt signaling critically regulates cell fate and proliferation in developmental stages and adult tissues. Redox regulation through nucleoredoxin (NRX) has recently been identified in canonical Wnt signaling. However, the source of reactive oxygen species (ROS) affecting the redox state of NRX remains elusive. Our principal aim in this study was to investigate whether superoxide-generating NADPH oxidase1 (Nox1) is involved in NRX-regulated Wnt signaling in intestinal and colon epithelial cells. Here, we demonstrate that Wnt treatment of mouse intestinal cells induces production of ROS through Nox1. This Nox1 action is regulated by Rac1 GTPase through Wnt-induced activation of the Rac1 guanine nucleotide exchange factor Vav2 by Src-mediated tyrosine phosphorylation. Nox1-generated ROS oxidize and inactivate NRX, thereby releasing the NRX-dependent suppression of Wnt-ß-catenin signaling through dissociation of NRX from Dvl. Nox1 small-interference RNA inhibits cell response to Wnt, including stabilization of ß-catenin, expression of cyclin D1 and c-Myc via the TCF transcription factor, and accelerated cell proliferation. Nox1 mediates Wnt-induced cell growth in colon cancer cells with the normal Wnt pathway, but not in APC-deficient colon cancer cells, which are constitutively active in Wnt signaling. Together, these results suggest the mediating role of Nox1 in redox-dependent regulation of canonical Wnt-ß-catenin signaling and provide further insight into the regulatory mechanism of the Wnt pathway.

Reactive oxygen generated by NADPH oxidase 1 (Nox1) contributes to cell invasion by regulating matrix metalloprotease-9 production and cell migration.

A mediating role of the reactive oxygen species-generating enzyme Nox1 has been suggested for Ras oncogene transformation phenotypes including anchorage-independent cell growth, augmented angiogenesis, and tumorigenesis. However, little is known about whether Nox1 signaling regulates cell invasiveness. Here, we report that the cell invasion activity was augmented in K-Ras-transformed normal rat kidney cells and attenuated by transfection of Nox1 small interference RNAs (siRNAs) into the cells. Diphenyleneiodonium (DPI) or Nox1 siRNAs blocked up-regulation of matrix metalloprotease-9 at both protein and mRNA levels in K-Ras-transformed normal rat kidney cells. Furthermore, DPI and Nox1 siRNAs inhibited the activation of IKKalpha kinase and the degradation of IkappaB alpha, suppressing the NFkappaB-dependent matrix metalloprotease-9 promoter activity. Additionally, epidermal growth factor-stimulated migration of CaCO-2 cells was abolished by DPI and Nox1 siRNAs, indicating the requirement of Nox1 activity for the motogenic effect of epidermal growth factor. This Nox1 action was mediated by down-regulation of the Rho activity through the low molecular weight protein-tyrosine phosphatase-p190RhoGAP-dependent mechanism. Taken together, our findings define a mediating role of Nox1-generated reactive oxygen species in cell invasion processes, most notably metalloprotease production and cell motile activity.

Roles of Nox1 and other Nox isoforms in cancer development.

The NADPH oxidase (Nox) family of enzymes generates reactive oxygen species (ROS). At low ROS concentration, intracellular signaling is initiated, whereas at high ROS concentration, oxidative stress is induced. The extensive studies over the years have shed light on the mediating roles of the Nox enzymes in a variety of normal physiological processes ranging from bactericidal activity to remodeling of the extracellular matrix. Consequently, imbalance of Nox activities could be the potential cause of acute or chronic diseases. With regard to functional relationships between Nox isoforms and pathogenesis, it is of particular interest to study whether they are involved in carcinogenesis, because overproduction of ROS has long been implicated as a risk factor in cancer development. We see one remarkable example of the causal relationship between Nox1 and cancer in Ras oncogene-induced cell transformation. Other studies also indicate that the Nox family of genes appears to be required for survival and growth of a subset of human cancer cells. Thus, the Nox family will be a focus of attention in cancer biology and etiology over the next couple years.

NADPH oxidase 4 contributes to transformation phenotype of melanoma cells by regulating G2-M cell cycle progression.

Generation of reactive oxygen species (ROS) has been implicated in carcinogenic development of melanoma, but the underlying molecular mechanism has not been fully elucidated. We studied the expression and function of the superoxide-generating NADPH oxidase (Nox)4 in human melanoma cells. Nox4 was up-regulated in 13 of 20 melanoma cell lines tested. Silencing of Nox4 expression in melanoma MM-BP cells by small interfering RNAs decreased ROS production and thereby inhibited anchorage-independent cell growth and tumorigenecity in nude mice. Consistently, a general Nox inhibitor, diphenylene iodonium, and antioxidants vitamine E and pyrrolidine dithiocarbamate blocked cell proliferation of MM-BP cells. Flow cytometric analysis indicated that Nox4 small interfering RNAs and diphenylene iodonium induced G(2)-M cell cycle arrest, which was also observed with another melanoma cell line, 928mel. This was accompanied by induction of the Tyr-15 phosphorylated, inactive form of cyclin-dependent kinase 1 (a hallmark of G(2)-M checkpoint) and hyperphosphorylation of cdc25c leading to its increased binding to 14-3-3 proteins. Ectopic expression of catalase, a scavenger of ROS, also caused accumulation of cells in G(2)-M phase. Immunohistochemistry revealed that expression of Nox4 was detected in 31.0% of 13 melanoma patients samples, suggesting the association of Nox4 expression with some steps of melanoma development. The findings suggest that Nox4-generated ROS are required for transformation phenotype of melanoma cells and contribute to melanoma growth through regulation of G(2)-M cell cycle progression.

A possible biochemical link between NADPH oxidase (Nox) 1 redox-signalling and ERp72.

Emerging evidence indicates that Nox (NADPH oxidase) 1-generated ROS (reactive oxygen species) play critical regulatory roles in various cellular processes, yet little is known of direct targets for the oxidase. In the present study we show that one of the proteins selectively oxidized in response to Nox1-generated ROS was ERp72 (endoplasmic reticulum protein 72 kDa) with TRX (thioredoxin) homology domains. Oxidation of ERp72 by Nox1 resulted in an inhibition of its reductase activity. EGF treatment of cells stimulated the Nox1 activity and the activated Nox1 subsequently mediated EGF-induced suppression of the ERp72 reductase activity. Co-immunoprecipitation, GST (glutathione transferase) pulldown assays and mutational analysis, indicated that Nox1 associates with ERp72, which involves its N-terminus encompassing a Ca(2+)-binding site and the first TRX-like motif. Furthermore, confocal microscopy showed co-localization between Nox1 and ERp72 at the plasma membrane. These results suggest that Nox1 functionally associates with ERp72, regulating redox-sensitive signalling pathways in a cellular context.

Randomized clinical trial of D2 and extended paraaortic lymphadenectomy in patients with gastric cancer.

BACKGROUND: The survival of patients with advanced gastric cancer after D2 dissection is still poor. Asian surgeons have proposed a more radical lymph node dissection, designated as D4 dissection, where paraaortic lymph nodes are removed in combination with D2 dissection. To evaluate the survival benefit of D4 dissection, a multi-institutional randomized trial of D2 vs D4 gastrectomy was conducted. METHODS: Patients enrolled in the study had potentially curable gastric adenocarcinoma at an advanced stage. Patients were randomized to undergo either D2 or D4 gastrectomy. RESULTS: Two hundred and ninety-three patients were registered and 269 patients were eligible; 135 patients were allocated to the D2 group and 134 to the D4 group. Five-year survival was 52.6% after D2 surgery and 55.0% after D4 gastrectomy. There was no significant difference in survival between the D2 and D4 groups (chi(2) = 0.064; P = 0.801). Hospital deaths occurred in 1 patients (0.7%) in the D2 group and 5 in the D4 group D4 gastrectomy is a more risky surgery than D2 dissection. Seven patients (5.2%) in the D2 and 15 (11.2%) in the D4 group died of causes other than gastric cancer recurrence. Sixty-three patients (46.7%) in the D2 group and 52 (38.8%) in the D4 group had disease recurrence. CONCLUSION: Prophylactic D4 dissection is not recommended for patients with potentially curable advanced gastric cancer.

Nox1 redox signaling mediates oncogenic Ras-induced disruption of stress fibers and focal adhesions by down-regulating Rho.

Generation of reactive oxygen species (ROS) by Ras oncogene-induced NADPH oxidase (Nox) 1 is required for Ras transformation phenotypes including anchorage-independent growth, morphological transformation, and tumorigenesity, but the signaling mechanism downstream of Nox1 remains elusive. Rho is known to be a critical regulator of actin stress fiber formation. Nonetheless, Rho was reported to no longer couple to loss of actin stress fibers in Ras-transformed Swiss3T3 cells despite the elevation of Rho activity. In this study, however, we demonstrate that Rho is inactivated in K-Ras-transformed normal rat kidney cells, and that abrogation of Nox1-generated ROS by Nox1 small interference RNAs or diphenyleneiodonium restores Rho activation, suggesting that Nox1-generated oxidants mediate down-regulation of the Rho activity. This down-regulation involves oxidative inactivation of the low molecular weight protein-tyrosine phosphatase by Nox1-generated ROS and a subsequent elevation in the tyrosine-phosphorylated active form of p190RhoGAP, the direct target of the phosphatase. Furthermore, the decreased Rho activity leads to disruption of both actin stress fibers and focal adhesions in Ras-transformed cells. As for Rac1, Rac1 also appears to participate in the down-regulation of Rho via Nox1. Our discovery defines a mediating role of Nox1-redox signaling for Ras oncogene-induced actin cytoskeletal changes.

A reducing and denaturing step maximizes the immunoprecipitations of m-calpain and I-2(PP2A)/SET: an approach toward antibodies that do not work well in immunoprecipitation.

Immunoprecipitation is an elegant method to isolate a specific protein of interest from a complex protein mixture such as cell lysate. We tried to increase the efficiency of m-calpain immunoprecipitation with anti-m-calpain antibodies directed toward denatured antigens that only work for immunoblotting and immunohistochemistry. We found that a reducing and denaturing step prior to immunoprecipitation greatly potentiates the efficiency of the immunoreaction. This improved method is also applicable for the immunoprecipitation of oncoprotein I-2(PP2A)/SET with antibodies directed toward a synthetic peptide that only work for immunoblotting. Thus, our improved method provides a way to maximize immunoprecipitation when using antibodies that do not work well under conventional immunoprecipitation conditions. Furthermore, the improved method is also suitable for decreasing the contaminating proteins during immunoprecipitation.

Metabolism and the urinary excretion profile of the recently scheduled designer drug N-Benzylpiperazine (BZP) in the rat.

The metabolism of N-benzylpiperazine (BZP), a recently scheduled designer drug, in the rat has been studied by analyzing its urinary metabolites. p-Hydroxy-BZP (p-OH-BZP) was unequivocally identified as the main metabolite along with a minor metabolite m-hydroxy-BZP (m-OH-BZP), using gas chromatography-mass spectrometry and high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI MS). The time-course excretion profiles of BZP, p-OH-BZP, and m-OH-BZP in the rats were investigated after a single intraperitoneal dosing of 5 mg/kg BZP, by using an optimized analytical procedure that combines solid-phase extraction and LC-ESI MS determination. The cumulative amounts excreted within the first 48 h were approximately 25% for p-OH-BZP and 2% for m-OH-BZP, whereas 6.7% dose of the parent drug BZP was excreted unchanged within 36 h post-dosing. The concentration ratio of p-OH-BZP to m-OH-BZP was 11.6 in the first 4 h, but it increased to 22.7 in 48 h with the elapsed time post-dosing. Most of p-OH-BZP was excreted in urine within approximately 36 h post-dosing, with approximately 50% appearing as the glucuronide conjugate. The present results suggest that p-OH-BZP is the most relevant metabolite to be detected for the proof of BZP intake in the forensic and clinical analysis of human urine.

Regulation of amphiphysin1 by mitogen-activated protein kinase: its significance in nerve growth factor receptor-mediated endocytosis.

Amphiphysin1, which can simultaneously bind to dynamin1 and the clathrin adaptor AP-2, is essential for dynamin1 recruitment during receptor-mediated endocytosis, but little is known about its regulatory mechanism. Here, we purified a 120-kDa mitogen-activated protein kinase (MAPK) substrate protein from porcine brains and identified the protein as amphiphysin1. Serine phosphorylation of amphiphysin1 was rapidly induced by nerve growth factor (NGF) in PC12 cells, and the induction was blocked by a MAPK inhibitor. Furthermore, when phosphorylated by MAPK in vitro or by NGF treatment in vivo, amphiphysin1 failed to bind to AP-2, but its association with dynamin1 was unaffected. Consistent with this, mutation of consensus MAPK phosphorylation sites increased amphiphysin1 binding to AP-2 and their intracellular colocalization. Thus, we propose that MAPK phosphorylation of amphiphysin1 controls NGF receptor/TrkA-mediated endocytosis by terminating the amphiphysin1-AP-2 interaction. This perhaps helps to regulate the availability of amphiphysin1-dynamin1 complexes for binding to the endocytic vesicle.

The superoxide-generating oxidase Nox1 is functionally required for Ras oncogene transformation.

The activated Ras oncogene can transform various mammalian cells and has been implicated in development of a high population of malignant human tumors. Recent studies suggest that generation of reactive oxygen species such as superoxide and H(2)O(2) is involved in cell transformation by the activated Ras. However, the nature of an oxidase participating in Ras-transformation is presently unknown. Here, we report that Ras oncogene up-regulates the expression of Nox1, a homologue of the catalytic subunit of the superoxide-generating NADPH oxidase, via the mitogen-activated protein kinase kinase-mitogen-activated protein kinase pathway, and that small interfering RNAs designed to target Nox1 mRNA effectively blocks the Ras transformed phenotypes including anchorage-independent growth, morphological changes, and production of tumors in athymic mice. Therefore, we propose that increased reactive oxygen species generation by Ras-induced Nox1 is required for oncogenic Ras transformation.