Functional Analysis of PTH1R Variants Found in Primary Failure of Eruption.

Although many variants of the parathyroid hormone 1 receptor (PTH1R) gene are known to be associated with primary failure of eruption (PFE), the mechanisms underlying the link remains poorly understood. We here performed functional analyses of PTH1R variants reported in PFE patients-namely, 356C>T (P119L), 395C>T (P132L), 439C>T (R147C), and 1148G>A (R383Q)-using HeLa cells with a lentiviral vector-mediated genetic modification. Two particular variants, P119L and P132L, had severe reduction in a level of N-linked glycosylation when compared with wild-type PTH1R, whereas the other 2 showed modest alteration. PTH1R having P119L or P132L showed marked decrease in the affinity to PTH1-34, which likely led to severely impaired cAMP accumulation upon stimulation in cells expressing these mutants, highlighting the importance of these 2 amino acid residues for ligand-mediated proper functioning of PTH1R. To further gain insights into PTH1R functions, we established the induced pluripotent stem cell (iPSC) lines from a patient with PFE and the heterozygous P132L mutation. When differentiated into osteoblastic-lineage cells, PFE-iPSCs showed no abnormality in mineralization. The mRNA expression of RUNX2, SP7, and BGLAP, the osteoblastic differentiation-related genes, and that of PTH1R were augmented in both PFE-iPSC-derived cells and control iPSC-derived cells in the presence of bone morphogenetic protein 2. Also, active vitamin D3 induced the expression of RANKL, a major key factor for osteoclastogenesis, equally in osteoblastic cells derived from control and PFE-iPSCs. In sharp contrast, exposure to PTH1-34 resulted in no induction of RANKL mRNA expression in the cells expressing P132L variant PTH1R, consistent with the idea that a type of heterozygous PTH1R gene mutation would spoil PTH-dependent response in osteoblasts. Collectively, this study demonstrates a link between PFE-associated genetic alteration and causative functional impairment of PTH1R, as well as a utility of iPSC-based disease modeling for future elucidation of pathogenesis in genetic disorders, including PFE.

A novel strategy inducing autophagic cell death in Burkitt's lymphoma cells with anti-CD19-targeted liposomal rapamycin.

Relapsed or refractory Burkitt's lymphoma often has a poor prognosis in spite of intensive chemotherapy that induces apoptotic and/or necrotic death of lymphoma cells. Rapamycin (Rap) brings about autophagy, and could be another treatment. Further, anti-CD19-targeted liposomal delivery may enable Rap to kill lymphoma cells specifically. Rap was encapsulated by anionic liposome and conjugated with anti-CD19 antibody (CD19-GL-Rap) or anti-CD2 antibody (CD2-GL-Rap) as a control. A fluorescent probe Cy5.5 was also liposomized in the same way (CD19 or CD2-GL-Cy5.5) to examine the efficacy of anti-CD19-targeted liposomal delivery into CD19-positive Burkitt's lymphoma cell line, SKW6.4. CD19-GL-Cy5.5 was more effectively uptaken into SKW6.4 cells than CD2-GL-Cy5.5 in vitro. When the cells were inoculated subcutaneously into nonobese diabetic/severe combined immunodeficiency mice, intravenously administered CD19-GL-Cy5.5 made the subcutaneous tumor fluorescent, while CD2-GL-Cy5.5 did not. Further, CD19-GL-Rap had a greater cytocidal effect on not only SKW6.4 cells but also Burkitt's lymphoma cells derived from patients than CD2-GL-Rap in vitro. The specific toxicity of CD19-GL-Rap was cancelled by neutralizing anti-CD19 antibody. The survival period of mice treated with intravenous CD19-GL-Rap was significantly longer than that of mice treated with CD2-GL-Rap after intraperitoneal inoculation of SKW6.4 cells. Anti-CD19-targeted liposomal Rap could be a promising lymphoma cell-specific treatment inducing autophagic cell death.

Fucosylated TGF-ß receptors transduces a signal for epithelial-mesenchymal transition in colorectal cancer cells.

BACKGROUND: Transforming growth factor-ß (TGF-ß) is a major inducer of epithelial-mesenchymal transition (EMT) in different cell types. TGF-ß-mediated EMT is thought to contribute to tumour cell spread and metastasis. Sialyl Lewis antigens synthesised by fucosyltransferase (FUT) 3 and FUT6 are highly expressed in patients with metastatic colorectal cancer (CRC) and are utilised as tumour markers for cancer detection and evaluation of treatment efficacy. However, the role of FUT3 and FUT6 in augmenting the malignant potential of CRC induced by TGF-ß is unclear. METHODS: Colorectal cancer cell lines were transfected with siRNAs for FUT3/6 and were examined by cell proliferation, invasion and migration assays. The expression and phosphorylation status of TGF-ß downstream molecules were analysed by western blot. Fucosylation of TGF-ß receptor (TßR) was examined by lectin blot analysis. RESULTS: Inhibition of FUT3/6 expression by siRNAs suppressed the fucosylation of type I TßR and phosphorylation of the downstream molecules, thereby inhibiting the invasion and migration of CRC cells by EMT. CONCLUSION: Fucosyltransferase 3/6 has an essential role in cancer cell adhesion to endothelial cells by upregulation of sialyl Lewis antigens and also by enhancement of cancer cell migration through TGF-ß-mediated EMT.

Stromal cells expressing hedgehog-interacting protein regulate the proliferation of myeloid neoplasms.

Aberrant reactivation of hedgehog (Hh) signaling has been described in a wide variety of human cancers including cancer stem cells. However, involvement of the Hh-signaling system in the bone marrow (BM) microenvironment during the development of myeloid neoplasms is unknown. In this study, we assessed the expression of Hh-related genes in primary human CD34(+) cells, CD34(+) blastic cells and BM stromal cells. Both Indian Hh (Ihh) and its signal transducer, smoothened (SMO), were expressed in CD34(+) acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS)-derived cells. However, Ihh expression was relatively low in BM stromal cells. Remarkably, expression of the intrinsic Hh-signaling inhibitor, human Hh-interacting protein (HHIP) in AML/MDS-derived stromal cells was markedly lower than in healthy donor-derived stromal cells. Moreover, HHIP expression levels in BM stromal cells highly correlated with their supporting activity for SMO(+) leukemic cells. Knockdown of HHIP gene in stromal cells increased their supporting activity although control cells marginally supported SMO(+) leukemic cell proliferation. The demethylating agent, 5-aza-2'-deoxycytidine rescued HHIP expression via demethylation of HHIP gene and reduced the leukemic cell-supporting activity of AML/MDS-derived stromal cells. This indicates that suppression of stromal HHIP could be associated with the proliferation of AML/MDS cells.

Combination therapy of an anticancer drug with the FNIII14 peptide of fibronectin effectively overcomes cell adhesion-mediated drug resistance of acute myelogenous leukemia.

We investigated whether FNIII14, a 22-mer peptide derived from fibronectin (FN) that potently impairs interaction of FN with beta1-integrin, could overcome cell adhesion-mediated drug resistance (CAM-DR) induced by very late antigen (VLA)-4-to-FN interaction in acute myelogenous leukemia (AML). Two AML cell lines, U937 cells and HL-60 cells, and fresh leukemic cells from six AML patients with high alpha4-integrin expression exhibited CAM-DR to cytosine arabinoside (Ara C) through VLA-4-to-FN interaction, while fresh leukemic cells from two AML patients with low alpha4-integrin expression did not display CAM-DR to Ara C. FNIII14 impaired VLA-4-to-FN interaction and restored sensitivity to Ara C in the CAM-DR leukemic cells. In these CAM-DR leukemic cells, upregulation of Bcl-2, which was induced through the focal adhesion kinase/Akt signal pathway upon VLA-4-to-FN interaction, was inhibited by FNIII14 treatment. In a mouse model of minimal residual disease (MRD) in bone marrow, 100% survival was achieved by combining FNIII14 with Ara C, whereas Ara C alone prolonged survival only slightly. The myelosuppression induced by Ara C was not augmented by the combination of FNIII14 in mouse experiments. Thus, the combination of anticancer drugs and FNIII14 holds promise to eradicate MRD in bone marrow after chemotherapy.

Phase I study of S-1, docetaxel and cisplatin combination chemotherapy in patients with unresectable metastatic gastric cancer.

The aim of this dose escalation study was to determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs) and preliminary efficacy of docetaxel, S-1 and cisplatin combination chemotherapy in patients with unresectable metastatic gastric cancer. Seventeen patients received oral S-1 (40 mg m(-2) bid) on days 1-14, intravenous cisplatin (60 mg m(-2)) and docetaxel (60, 70 or 80 mg m(-2) depending on DLT) on day 8 every 3 weeks. The MTD of this combination was presumed to be docetaxel 70 mg m(-2). At this dose level, 40% of the patients (two of five) developed grade 4 neutropenia and 20% (one of five) exhibited grade 3 nausea during the first course. Therefore, the recommended dose of docetaxel was defined as 60 mg m(-2). The DLT was neutropenia. The response rate (RR) was 88.2% (15 of 17), consisting of one complete response and 14 partial responses. There were two stable diseases but no progressive disease. Of these 15 responders, four (23.5%) with high VEGF expression showed rapid tumour regression and achieved downstaging, leading to subsequent curative gastrectomy. Three of these have been disease free for about 3 years, suggesting a complete cure. In conclusion, this regimen was tolerable and showed a quite high RR, with an appreciable downstaging rate in metastatic gastric cancer.

Hepatitis C virus core protein promotes proliferation of human hepatoma cells through enhancement of transforming growth factor alpha expression via activation of nuclear factor-kappaB.

BACKGROUND: Hepatitis C virus (HCV) infection is a major cause of human hepatocellular carcinoma (HCC). The precise mechanism of hepatocarcinogenesis in humans by HCV is currently unclear. It was recently shown, however, that transgenic mice with the HCV core gene often develop HCC, suggesting tumorigenic activity of the HCV core protein. Further, the HCV core protein expressed in HepG2 cells transfected with the core gene was shown to stimulate proliferation of transfectants through activation of nuclear factor-kappaB (NF-kappaB). The downstream target molecule(s) of NF-kappaB activated by the HCV core protein to evoke cell proliferation is not yet identified. Transforming growth factor (TGF) alpha, which is often overexpressed in various tumour tissues such as HCC, has been shown to stimulate hepatocyte proliferation through activation of the mitogen-activated protein kinase or extracellular signal-related protein kinase (MAPK/ERK) cascade. AIMS: To explore the possibility that TGFalpha might be a target molecule for NF-kappaB activated by the HCV core, and that TGFalpha participates in the growth promotion of the core transfectants in an autocrine manner, activating the MAPK/ERK pathway. METHODS: A HCV core expression vector was transfected into human hepatoma Huh-7, HepG2 and Hep3B cells. NF-kappaB activity was examined by an electrophoretic mobility shift assay. TGFalpha transcription was assessed by a luciferase reporter assay. TGFalpha protein was determined by immunoblot and ELISA. MAPK/ERK activity was examined by an in vitro kinase assay. Cell proliferation was assessed by a water-soluble tetrazolium salt-1 assay. RESULTS: In the HCV core transfectants, NF-kappaB bound to the kappaB site in the TGFalpha proximal promoter region, resulting in an increase in TGFalpha transcription. Immunoblot as well as ELISA showed increased TGFalpha expression in the HCV core transfectants. SN50, a specific inhibitory peptide for NF-kappaB, cancelled HCV core-induced TGFalpha expression. HCV core protein increased cell proliferation as well as ERK activity of the HCV core transfectants as compared with the mock transfectants. The growth-promoting activity and activation of ERK by the HCV core protein were negated by treatment with anti-TGFalpha antibodies. CONCLUSIONS: These results suggest that the HCV core protein promotes proliferation of human hepatoma cells by activation of the MAPK/ERK pathway through up regulation of TGFalpha transcription via activation of NF-kappaB. Our finding provides a new insight into the mechanism of hepatocarcinogenesis by HCV infection.

Involvement of transforming growth factor-beta and thrombopoietin in the pathogenesis of myelodysplastic syndrome with myelofibrosis.

We investigated the cause of myelofibrosis and proliferation of megakaryocytes in myelodysplastic syndrome with myelofibrosis (MDS-MF (+)). Plasma-transforming growth factor-beta1 (PTGF-beta1) concentrations closely correlated with myelofibrosis grade in MDS-MF (+) and were higher than those in idiopathic myelofibrosis (IMF), essential thrombocythemia (ET), idiopathic thrombocytopenic purpura (ITP), MDS-without MF (MDS-MF (-)) or healthy volunteers (HV). Peripheral blood mononuclear cells from MDS-MF (+) patients expressed more TGF-beta1 mRNA than those from IMF, MDS-MF (-) or HV. When we immunostained bone marrow specimens of MDS-MF (+) for TGF-beta, the intensity of blasts was apparently higher than that of megakaryocytes, while in MDS-MF (-), megakaryocytes were immunostained with a similar intensity as that in MDS-MF (+), but blasts were negative for staining. In IMF, megakaryocytes, monocytes and small mononuclear cells representing CD34+ cells were all similarly stained with a much lower intensity than that of blasts in MDS-MF (+). The number of bone marrow megakaryocytes were increased the most in MDS-MF (+), followed by ET, ITP, MDS-MF (-) and NHL and correlated with plasma thrombopoietin (TPO) levels or with plasma TGF-beta1 levels, respectively, in each disease. Thus, in MDS-MF (+), both myelofibrosis and the increased megakaryocytes were ascribed to overproduction of TGF-beta1 from blasts.

A case of subcutaneous phaeohyphomycotic cyst due to Exophiala jeanselmei complicated with systemic lupus erythematosus.

We report a case of subcutaneous phaeohyphomycosis by Exophiala jeanselmei that appeared on the extensor surface of the left lower leg of a 34-year-old woman with systemic lupus erythematosus (SLE). The superficial symptoms were a subcutaneous nodule 2.5 x 2 cm in size discharging a serous exudate from its center. Histopathological examination revealed granulomatous changes including large numbers of neutrophils in the dermis and the subcutaneous tissues. In addition, periodic acid-Schiff-positive fungal elements consisting of many yeast-like cells and chains of cells with hyphae were seen. The statistics on E. jeanselmei infections in Japan indicated that 54 cases (24 in men and 30 in women) had been reported, of which 50 (21 in men and 29 in women) were phaeohyphomycosis, and about half had underlying diseases; and the sites of the lesions were mainly on the extremities.

Normalization of elevated hepatic 8-hydroxy-2'-deoxyguanosine levels in chronic hepatitis C patients by phlebotomy and low iron diet.

Accumulation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA, which may result from the continuous reactive oxygen species (ROS) generation associated with chronic inflammation, has been reported in various human preneoplastic lesions and in cancerous tissues. However, no direct causative relationship between the 8-OHdG formation and carcinogenesis has been thus far demonstrated in humans. Directly proving the causality requires showing that depletion of 8-OHdG levels in tissue by interfering with ROS generation results in a reduction in cancer. Chronic hepatitis C virus (HCV) infection is associated with a high risk of hepatocellular carcinoma (HCC). Several studies on patients with chronic HCV have shown that hepatic iron overload is attributable to liver injury and that iron depletion improved serum aminotransferase levels. Excess iron is known to generate ROS within cells, which causes mutagenic lesions, such as 8-OHdG. In this study, therefore, we have evaluated whether therapeutic iron reduction (phlebotomy and low iron diet) with a long-term follow-up (6 years) would decrease the hepatic 8-OHdG levels and the risk of HCC development in patients with chronic HCV. Patients (34) enrolled were those who had undergone standard IFN therapy but had no sustained response. Quantitative immunohistochemistry using the KS-400 image analyzing system and electrochemical detection was used for 8-OHdG detection. With this treatment, elevated hepatic 8-OHdG levels in patients with chronic hepatitis C (8.3 +/- 4.6/10(5) dG) significantly decreased to almost normal levels (2.2 +/- 0.9/10(5) dG; P < 0.001) with concomitant improvement of hepatitis severity, including fibrosis, whereas HCV titers were unaffected. None of these patients developed HCC. Thus, long-term iron reduction therapy in patients with chronic hepatitis C may potentially lower the risk of progression to HCC.

hADA3 is required for p53 activity.

The tumor suppressor protein p53 is a transcription factor that is frequently mutated in human cancers. In response to DNA damage, p53 protein is stabilized and activated by post-translational modifications that enable it to induce either apoptosis or cell cycle arrest. Using a novel yeast p53 dissociator assay, we identify hADA3, a part of histone acetyltransferase complexes, as an important cofactor for p53 activity. p53 and hADA3 physically interact in human cells. This interaction is enhanced dramatically after DNA damage due to phosphorylation event(s) in the p53 N-terminus. Proper hADA3 function is essential for full transcriptional activity of p53 and p53-mediated apoptosis.

Glutathione S-transferase-pi overexpression is closely associated with K-ras mutation during human colon carcinogenesis.

BACKGROUND & AIMS: In colorectal adenoma and carcinoma, glutathione S-transferase-pi (GSTP1-1) is highly expressed. K-ras mutation is also known to occur frequently in colorectal adenoma and carcinoma, as well as in the putative precursor of adenoma, aberrant crypt foci (ACF). Further, forced expression of v-H-ras in rat liver epithelial cells has been shown to enhance rat pi-class GST expression. The aim of the present study is, therefore, to investigate the causative relationship between GSTP1-1 overexpression and K-ras mutation in these lesions. METHODS: Twenty-seven specimens of colorectal carcinoma, 24 of adenoma, and 28 of ACF were examined in this study. The expression of GSTP1-1 or p21(K-ras) was examined by immunohistochemistry. The GSTP1-1 messenger RNA levels were measured by TaqMan reverse-transcription polymerase chain reaction (PCR). K-ras mutation was detected by two-step PCR restriction fragment length polymorphism. v-K-ras transfection to RPMI-4788 colon carcinoma cells was carried out by the lipofection method. Activities of GSTP1-1 promoters containing AP-1 and Sp1 responsive elements in the v-K-ras transfectants were measured by a secreted form of human placental alkaline phosphatase (SEAP) assay. Nuclear protein from these transfectants bound to the GSTP1-1 promoter was analyzed by electrophoretic mobility shift assay (EMSA). RESULTS: In human colorectal carcinoma, adenoma, and ACF, close association of increased expression of GSTP1-1 with K-ras mutation was observed. v-K-ras transfectants showed significantly higher SEAP activity than that of mock-transfectant activity. EMSA showed specific interaction of AP-1 with promoter of GSTP1-1. CONCLUSIONS: It is highly plausible that GSTP1-1 overexpression in ACF, colorectal adenoma, and carcinoma is induced by K-ras mutation via AP-1 activation.

The bile acid glycochenodeoxycholate induces trail-receptor 2/DR5 expression and apoptosis.

Toxic bile salts induce hepatocyte apoptosis by both Fas-dependent and -independent mechanisms. In this study, we examined the cellular mechanisms responsible for Fas-independent, bile acid-mediated apoptosis. HuH-7 cells, which are known to be Fas deficient, were stably transfected with the sodium-dependent bile acid transporting polypeptide. The toxic bile acid glycochenodeoxycholate (GCDC)-induced apoptosis in these cells in a time- and concentration-dependent manner. Apoptosis and mitochondrial cytochrome c release were inhibited by transfection with dominant negative FADD, CrmA transfection, or treatment with the selective caspase 8 inhibitor IETD-CHO. These observations suggested the Fas-independent apoptosis was also death receptor mediated. Reverse transcriptase-polymerase chain reaction demonstrated tumor necrosis factor-R1, tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-R1/DR4, -R2/DR5, and TRAIL, but not tumor necrosis factor-alpha expression by these cells. GCDC treatment increased expression of TRAIL-R2/DR5 mRNA and protein 10-fold while expression of TRAIL-R1 was unchanged. Furthermore, aggregation of TRAIL-R2/DR5, but not TRAIL-R1/DR4 was observed following GCDC treatment of the cells. Induction of TRAIL-R2/DR5 expression and apoptosis by bile acids provides new insights into the mechanisms of hepatocyte apoptosis and the regulation of TRAIL-R2/DR5 expression.

Analysis of K-ras, APC, and beta-catenin in aberrant crypt foci in sporadic adenoma, cancer, and familial adenomatous polyposis.

BACKGROUND & AIMS: We have previously shown that aberrant crypt foci (ACF) are the putative precursor lesions of colorectal adenomas and subsequent cancer in humans using magnifying endoscopy. The present study was designed to investigate these genetic alterations in ACF biopsy specimens from normal subjects, familial adenomatous polyposis (FAP) or sporadic patients. METHODS: The non-FAP cases included 34 normal subjects, 35 colorectal adenoma patients, and 19 colorectal cancer patients; there were 4 FAP patients. Biopsies were performed on ACF by magnifying endoscopy. K-ras mutations were analyzed by 2-step polymerase chain reaction and restriction fragment length polymorphism, APC mutations by in vitro-synthesized protein assay, and beta-catenin mutations by direct sequencing. Full-length APC and beta-catenin were detected by immunofluorescence. RESULTS: In non-FAP cases, K-ras mutations were detected in 82% (89/106) of nondysplastic ACF and 63% (17/27) of dysplastic ACF. APC mutation and beta-catenin accumulation were not detected in non-FAP ACF, whereas in adenoma of these patients, positivity of APC mutation and beta-catenin accumulation were 78% (24/31), and that of K-ras mutation was 65% (20/31). FAP patients showed K-ras mutations in only 13% (1/8) of dysplastic ACF, which is the predominant form of ACF found in FAP. In FAP patients, somatic APC mutations were found in 100% of dysplastic ACF, as they are in adenoma. The frequency of K-ras mutations was 73% (8 of 11) in FAP adenoma. CONCLUSIONS: The data suggest that in sporadic colorectal carcinogenesis, assuming the biological implication of ACF as a precursor of adenomas, there is a route where K-ras mutation mainly occurs during the formation of ACF, which then become adenomas wherein APC mutation occurs. In FAP, however, somatic mutation of APC predominantly occurs during ACF formation, followed by K-ras mutation.

A mutation, in the iron-responsive element of H ferritin mRNA, causing autosomal dominant iron overload.

Ferritin, which is composed of H and L subunits, plays an important role in iron storage and in the control of intracellular iron distribution. Synthesis of both ferritin subunits is controlled by a common cytosolic protein, iron regulatory protein (IRP), which binds to the iron-responsive element (IRE) in the 5'-UTR of the H- and L-ferritin mRNAs. In the present study, we have identified a single point mutation (A49U) in the IRE motif of H-ferritin mRNA, in four of seven members of a Japanese family affected by dominantly inherited iron overload. Gel-shift mobility assay and Scatchard-plot analysis revealed that a mutated IRE probe had a higher binding affinity to IRP than did the wild-type probe. When mutated H subunit was overexpressed in COS-1 cells, suppression of H-subunit synthesis and of the increment of radiolabeled iron uptake were observed. These data suggest that the A49U mutation in the IRE of H-subunit is responsible for tissue iron deposition and is a novel cause of hereditary iron overload, most likely related to impairment of the ferroxidase activity generated by H subunit.

Enhanced TRAIL sensitivity by p53 overexpression in human cancer but not normal cell lines.

The cytotoxic ligand TRAIL is a promising anti-cancer agent that is entering into clinical trials. We previously identified a major subgroup of TRAIL resistant cancer cell lines with absent, or reduced DR4 expression containing a K441R polymorphism or harboring elevated levels of the caspase activation inhibitor FLIP. In the present study, we explored the use of a gene therapeutic approach utilizing p53, delivered by an adenovirus-p53 (Ad-p53) vector, which directly controls expression of the TRAIL receptor KILLER/DR5 in a panel of 8 cell lines including normal and TRAIL sensitive or resistant cancers. The functional status of the delivered p53 was monitored by detection of induced p21WAF1 expression by immunocytochemistry. In normal cells, which are TRAIL resistant, TRAIL did not reduce cell viability over and above the effect of Ad-p53 alone. All cancer cell lines were sensitive to Ad-p53 and up-regulated expression of the TRAIL receptor KILLER/DR5. TRAIL-resistant cancer cells became more sensitive to TRAIL at low Ad-p53 multiplicities of infection but TRAIL resistance was not completely overcome in one TRAIL-resistant cell line probably because of a high level of expression of FLIP. The results reveal that Ad-p53 induces the TRAIL receptor KILLER/DR5 and, like radiation or chemotherapy may effectively reverse TRAIL resistance.

Wild-type p53 transactivates the KILLER/DR5 gene through an intronic sequence-specific DNA-binding site.

KILLER/DR5, a tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor gene, has been shown to be induced by DNA damaging agents and radiation in a p53-dependent manner. Although TRAIL is a potential therapeutic agent for cancer, the induction mechanism of its receptors is poorly understood. Here we show the identification of three p53 DNA-binding sites in the KILLER/DR5 genomic locus located upstream (BS1; -0.82 Kb) of the ATG site, within Intron 1 (BS2; +0.25 Kb downstream of the ATG) and within Intron 2 (BS3; +1.25 Kb downstream of the ATG). A modified p53-binding and immunoselection protocol using a wild-type p53-expressing adenovirus vector (Ad-p53) was used to identify the binding sites and to show that each binding site can bind specifically to wild-type p53 protein (wt-p53). A reporter assay revealed that only BS2 could enhance luciferase expression driven by a basal promoter. We constructed a reporter plasmid carrying the genomic regulatory region of KILLER/DR5 including the three p53 DNA-binding sites but no additional basal promoter. The genomic fragment showed basal transcriptional activity which was induced by wt-p53 but not by mutant p53, and human papilloma virus E6 inhibited the p53-dependent activation. Mutation of BS2 abrogated not only the binding activity of wt-p53 but also the induction of the KILLER/DR5 genomic promoter-reporter gene, indicating that BS2 is responsible for the p53-dependent transactivation of KILLER/ DR5. In p53-wild-type but not -mutant or -null cell lines, doxorubicin treatment stabilized p53 protein, and increased specific binding to BS2 as revealed by EMSA, and upregulated the KILLER/DR5 promoter-luciferase reporter gene. These results suggest that the transactivation of KILLER/DR5 is directly regulated by exogenous or endogenous wt-p53 and establishes KILLER/DR5 as a p53 target gene that can signal apoptotic death.

Histological increase in inflammatory infiltrate in sun-exposed skin of female subjects: the possible involvement of matrix metalloproteinase-1 produced by inflammatory infiltrate on collagen degradation.

To investigate morphological changes occurring during cutaneous photoageing, a correlation between the number of infiltrating cells in the dermis and the degree of collagen damage was examined using sections from clinically normal chronically sun-exposed and sun-protected skin of Japanese female subjects. Haematoxylin and eosin-stained sections from 134 sun-exposed (subjects aged 3-82 years) and 73 sun-protected (subjects aged 1-86 years) areas demonstrated a predominant lymphoid cell and to a lesser extent histiocyte infiltration. The mean +/- SD number of lymphoid cells and histiocytes in the sun-exposed skin sections (427.0+/-192.2 and 147.8+/-83.3 cells/mm2, respectively) was significantly higher than in the sun-protected skin sections (292.6+/-98.3 and 125.9+/-59.0 cells/mm2, respectively) (P < 0.001 and P < 0.05, respectively), and the number of lymphoid cells in the sun-exposed skin sections increased significantly with age up to 50 years (r = 0.400, P < 0.001). Sun-exposed skin sections with severe collagen degeneration had a significantly higher number of lymphoid cells than those with slightly degenerated collagen (mean 626.3 vs. 482.4 cells/mm2, P < 0.01). The mean count of mast cells in sun-exposed skin was 202.0 cells/mm2; this did not vary with the age of the subjects or the level of collagen damage. Immunohistochemical studies using 24 frozen sections identified most of the lymphoid cells infiltrating sun-exposed skin as memory T lymphocytes (CD3+, CD4+ and CD45RO+). The number of cells which displayed immunoreactivity to matrix metalloproteinase (MMP)-1 in the sun-exposed skin sections was significantly higher than in the sun-protected skin sections (mean 170.2 vs. 113.6 cells/mm2, P < 0.05). Among these cells were observed CD3 and MMP-1 double-stained T lymphocytes, and T lymphocytes contacting MMP-1-positive cells. These morphological observations suggest that T lymphocytes infiltrating photodamaged skin may play a part in the degeneration and reduction of collagen through MMP-1 activity.