Faculty Bibliography

Contact sensitizers are a major cause of inflammatory skin disease and as topical immunomodulators also have the potential for treating cancer, viral diseases and certain autoimmune disorders. In the present study, the authors identify the upregulation of the TH17 lymphocyte subset transcription factor retinoid orphan receptor gamma T (RORgammaT) and the CD70 costimulatory pathway in human contact sensitivity (CS) using molecular techniques. Identification of this important new subset of T lymphocytes and a recognized costimulatory pathway offers potential for ameliorating CS and insight into antitumor and antiviral mechanism of haptens as topical immunomodulators

We evaluated the mechanisms using immunohistochemistry whereby chrysotile asbestos and benzo(a)pyrene (BaP) instilled intratracheally into lung-specific dominant-negative p53 (dnp53) mice might interact in causing lung carcinomas and fibrosis. Chrysotile asbestos and benzo(a)pyrene (BaP) were instilled intratracheally into lung-specific dominant-negative p53 (dnp53) and control mice. The mice were sacrificed at 12 months and their lungs examined for lung carcinomas and fibrosis. Immunostains for proteins related to apoptosis, fibrogenesis, matrix remodeling and inflammation were performed. The dnp53 mice had increased numbers of lung adenocarcinomas with BaP alone and the combination of chrysotile and BaP (the latter was additive but not significant). Several atypical adenomatous hyperplasia lesions were found in the combined treatment group. dnp53 and FVBN control mice developed nodular buds of fibrotic lung tissue after chrysotile asbestos exposure that were localized in respiratory bronchioles; these lesions had significant increases in immunohistochemical staining for TGF-beta, MMP-7 and -9, MIG-1, and SDF-1. Fibrotic lesions in mice exposed to chrysotile had increased collagen demonstrated by picrosirius red staining. The dnp53 mice with adenocarcinomas had increased SDF-1, TGF-beta, MMP-9 and -7, Cyclin D, and MIG-1 immunostaining in the chrysotile and combined treatment groups. We conclude that BaP and the combination of BaP plus chrysotile asbestos are potent inducers of adenocarcinoma in dnp53 mice and that the inflammatory cytokines and proteases MMP-7 and -9, MIG-1, and SDF-1, and growth factors Cyclin D and TGF-beta are increased in the specific lesions

N-myc down-regulated gene 1 (NDRG1/Cap43) is inducible by a variety of environmental stressors, including hypoxia. The present study identified a cis-acting element mediating the transactivation of the NDRG1 gene in murine RAW264.7 macrophage cells treated with hypoxia or deferoxamine, an iron chelator mimicking hypoxia. Through a series of deletions of the promoter of NDRG1 luciferase constructs, a minimal cis-acting element conferring inducibility by hypoxia and deferoxamine was localized to an early growth response 1 (Egr-1) and Sp1 overlapping binding site. Electrophoretic mobility shift assay, antibody supershift assay, and mutations of the Egr-1 binding site confirmed the specific binding of Egr-1 protein to this Egr-1/Sp1 motif. In addition, hypoxia increased the level of Egr-1 protein that correlated with induction of NDRG1 expression at both RNA and protein levels. Transient transfection of the Egr-1 gene into HeLa cells also resulted in up-regulation of the NDRG1 mRNA. The role of Egr-1 was further verified by mutations in the Egr-1 binding site, which reduced promoter inducibility by hypoxia and deferoxamine. Furthermore, the induction of NDRG1 expression by hypoxia and deferoxamine was diminished by RNA interference knockdown of Egr-1 gene expression and in Egr-1-/- mouse embryonic fibroblasts (MEF) compared with Egr-1+/- MEFs. These results showed for the first time that Egr-1 regulates NDRG1 transcription through an overlapping Egr-1/Sp1 binding site that acts as a major site of positive regulation of the NDRG1 promoter by hypoxia signaling

To investigate the effectiveness of passive antibody treatment as post-exposure therapy for ricin, we had developed an oropharyngeal aspiration model for ricin lethal challenge and antibody administration. When polyclonal anti-deglycosylated ricin A-chain antibody (dgA Ab) was administered between 1-18 hr after ricin challenge, all animals survived while delayed treatment to 24 hr resulted in 30% survival. The protective effects of dgA Ab correlated with inhibition of apoptosis in the lungs in vivo and in RAW264.7 macrophage and Jurkat T cells in vitro. In addition, ricin-induced cell cytotoxicity was inhibited by both dgA Ab and RAC18 monoclonal antibody against ricin A-chain. Administration of RAC18 monoclonal antibody at 4, 18, and 24 hr after ricin exposure resulted in 100%, 60% and 50% protection, respectively, suggesting that the therapeutic window for passive vaccination extended to at least 24 hr post-ricin lung challenge

AIM: To evaluate the role of N-myc downstream-regulated gene 1 (NDRG1) expression in prognosis and survival of colorectal cancer patients with different ethnic backgrounds. METHODS: Because NDRG1 is a downstream target of p53 and hypoxia inducible factor-1 alpha (HIF-1 alpha), we examined NDRG1 expression together with p53 and HIF-1 alpha by immunohistochemistry. A total of 157 colorectal cancer specimens including 80 from Japanese patients and 77 from US patients were examined. The correlation between protein expression with clinicopathological features and survival after surgery was analyzed. RESULTS: NDRG1 protein was significantly increased in colorectal tumor compared with normal epithelium in both Japanese and US patient groups. Expression of NDRG1 protein was significantly correlated with lymphatic invasion, venous invasion, depth of invasion, histopathological type, and Dukes' stage in Japanese colorectal cancer patients. NDRG1 expression was correlated to histopathological type, Dukes' stage and HIF-1 alpha expression in US-Caucasian patients but not in US-African American patients. Interestingly, Kaplan-Meier survival analysis demonstrated that NDRG1 expression correlated significantly with poorer survival in US-African American patients but not in other patient groups. However, in p53-positive US cases, NDRG1 positivity correlated significantly with better survival. In addition, NDRG1 expression also correlated significantly with improved survival in US patients with stages III and IV tumors without chemotherapy. In Japanese patients with stages II and III tumors, strong NDRG1 staining in p53-positive tumors correlated significantly with improved survival but negatively in patients without chemotherapy. CONCLUSION: NDRG1 expression was correlated with various clinicopathological features and clinical outcomes in colorectal cancer depending on the race/ethnicity of the patients. NDRG1 may serve as a biological basis for the disparity of clinical outcomes of colorectal cancer patients with different ethnic backgrounds.

Leprosy or Hansen's disease is a chronic infectious disease caused by an acid-fast bacillus, Mycobacterium leprae (M. leprae). The bacilli proliferate in macrophages infiltrating the skin and gain entry to the dermal nerves via the laminar surface of Schwann cells where they replicate. After entry, the Schwann cells proliferate and then die. Conclusive identification of M. leprae DNA in a sample can be obtained by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for the heat shock 65 gene (hsp65). Molecular epidemiology will make it possible to study the global distributions of M. leprae, explore the relationship between genotypes-incidence rates, mode of transmission, and the type of disease (tuberculoid vs. lepromatous). We amplified DNA using PCR for the hsp65 gene from 24 skin lesions from patients diagnosed with various types of leprosy. Fifteen out of 24 were positive for the hsp65 gene. Digestion with HaeIII-PAGE for the RFLP confirmation of the presence of M. leprae DNA showed the typical pattern in 5 out of 24 and 2 novel patterns in 10 out of 24 patients. We confirmed the presence of M. leprae DNA by sequencing the genes for gyraseA or B and folP, which contained only M. leprae specific single nucleotide polymorphisms (SNPs). Thus, we describe novel hsp65 RFLPs for M. leprae found in a high frequency making them ideal for future epidemiology and transmission studies

Asbestos and benzo(a)pyrene diol epoxide (BPDE) are pulmonary carcinogens with synergistic interaction in causing lung cancer. We used Affymetrix microarrays to study gene modulation in vitro using normal human bronchial epithelial cells exposed to chrysotile asbestos and/or BPDE for 4 or 24 h. Linear models were used to compare treated cells to controls at each time point to identify statistically significant up- or downregulation of genes. Profiles of genes regulated by chrysotile were dominated by cytokines, growth factors, and DNA damage. Profiles of genes with BPDE and chrysotile regulation were correlated with proliferation, DNA damage recognition and nucleotide-excision repair, cytokines, and apoptosis. Chemokines, growth-regulated oncogene-alpha (Gro-alpha, CXCL-1), and IL-8, were significantly increased, and these had previously been observed in bronchoalveolar lavage from asbestos workers or in animal models. Interestingly, the Hermansky-Pudlak gene, which is mutated in an autosomal recessive form of pulmonary fibrosis, was downregulated threefold by BPDE at 4 h. This is an interesting example of gene (Hermansky-Pudlak syndrome) and environment (BPDE) interaction. Transcription factors, including activating transcription factor 3 and Cbp/p300-interacting transactivator, were upregulated by chrysotile. Real Time PCR for IL-8, ATF-3, GADD45B, CXC Ligand 1, and CTGF compared to GAPDH validated microarray findings at 24 h. These in vitro findings in NHBE cells model environment-gene interaction for asbestos and BPDE, highlighting effects of inflammation, fibrosis, proliferation, and DNA damage recognition and repair

BACKGROUND: Non-small cell lung cancer is the most common cause of early casualty from malignant disease in western countries. The heterogeneous nature of these cells has been identified by histochemical and microarray biomarker analyses. Unfortunately, the morphological, molecular and biological variation within cell lines used as models for invasion and metastasis are not well understood. In this study, we test the hypothesis that heterogeneous cancer cells exhibit variable motility responses such as chemokinesis and chemotaxis that can be characterized molecularly. METHODS: A subpopulation of H460 lung cancer cells called KINE that migrated under chemokinetic (no gradient) conditions was harvested from Boyden chambers and cultured. Time-lapsed microscopy, immunofluorescence microscopy and microarray analyses were then carried out comparing chemokinetic KINE cells with the unselected CON cell population. RESULTS: Time-lapsed microscopy and analysis showed that KINE cells moved faster but less directionally than the unselected control population (CON), confirming their chemokinetic character. Of note was that chemokinetic KINE cells also chemotaxed efficiently. KINE cells were less adhesive to substrate than CON cells and demonstrated loss of mature focal adhesions at the leading edge and the presence of non-focalized cortical actin. These characteristics are common in highly motile amoeboid cells that may favour faster motility speeds. KINE cells were also significantly more invasive compared to CON. Gene array studies and real-time PCR showed the downregulation of a gene called, ROM, in highly chemokinetic KINE compared to mainly chemotactic CON cells. ROM was also reduced in expression in a panel of lung cancer cell lines compared to normal lung cells. CONCLUSION: This study shows that cancer cells that are efficient in both chemokinesis and chemotaxis demonstrate high invasion levels. These cells possess different morphological, cytoskeletal and adhesive properties from another population that are only efficient at chemotaxis, indicating a loss in polarity. Understanding the regulation of polarity in the context of cell motility is important in order to improve control and inhibition of invasion and metastasis