Differential regulation of iron chelator-induced IL-8 synthesis via MAP kinase and NF-κB in immortalized and malignant oral keratinocytes

Abstract Background Interleukin-8 (IL-8) is a cytokine that plays an important role in tumor progression in a variety of cancer types; however, its regulation is not well understood in oral cancer cells. In the present study, we examined the expression and mechanism of IL-8 in which it is involved by treating immortalized (IHOK) and malignant human oral keratinocytes (HN12) cells with deferoxamine (DFO). Methods IL-8 production was measured by an enzyme-linked immunoabsorbent assay and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Electrophoretic mobility shift assays was used to determine NF-κB binding activity. Phosphorylation and degradation of the I-κB were analyized by Western blot. Results IHOK cells incubated with DFO showed increased expression of IL-8 mRNA, as well as higher release of the IL-8 protein. The up-regulation of DFO-induced IL-8 expression was higher in IHOK cells than in HN12 cells and was concentration-dependent. DFO acted additively with IL-1β to strongly up-regulate IL-8 in IHOK cells but not in HN12 cells. Accordingly, selective p38 and ERK1/2 inhibitors for both kinases abolished DFO-induced IL-8 expression in both IHOK and HN12 cells. Furthermore, DFO induced the degradation and phosphorylation of IκB, and activation of NF-κB. The IL-8 inducing effects of DFO were mediated by a nitric oxide donor (S-nitrosoglutathione), and by pyrrolidine dithiocarbamate, an inhibitor of NF-κB, as well as by wortmannin, which inhibits the phosphatidylinositol 3-kinase-dependent activation of NAD(P)H oxidase. Conclusion This results demonstrate that DFO-induced IL-8 acts via multiple signaling pathways in immortalized and malignant oral keratinocytes, and that the control of IL-8 may be an important target for immunotheraphy against human oral premalignant lesions.</p

Comment letters to the National Commission on Commission on Fraudulent Financial Reporting, 1987 (Treadway Commission) Vol. 1

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Cultural Differences in Organizational Citizenship Behavior: A Comparison Between Chinese and American Employees

The present study examined the differences in the perceptions of organizational citizenship behavior (OCB) between Chinese and American employees. Survey responses concerning the presence of OCB in their organizations were collected from a total of 393 employees. Analyses showed that Chinese and American employees reported similar levels of personal support and conscientious initiative in their organizations, but Chinese employees reported higher levels of organizational support in comparison with American employees. In addition, results indicated that perceptions of personal support, organizational support, and conscientious initiative were a function of job/hierarchical level such that management reported lower levels on all three dimensions of OCB. Finally, the results showed that country and job/hierarchical level do not interact to influence perceptions of organizational citizenship behavior. Implications and directions for future research on cultural differences in organizational citizenship behavior are discussed

Diversity Cues on Recruitment Websites: Investigating the Effects on Job Seekers\u27 Information Processing

Although job seekers\u27 motivation to process the information encountered during recruitment partially influences recruitment success, little is known about what motivates more thorough information processing. To address this issue, we integrated recruitment and social information processing theories to examine the possibility that diversity cues on recruitment websites influence website viewers\u27 processing of presented information. Utilizing a controlled experiment and a hypothetical organization, Study I revealed that both Blacks and Whites spent more time viewing recruitment websites and better recalled website information when the sites included racial diversity cues. These relationships were stronger for Blacks, and organizational attractiveness perceptions mediated these effects for Blacks but not for Whites. Study 2 found similar relationships for Black and White participants viewing real organizational recruitment websites after taking into account perceived organizational attributes and website design effects. Implications of these findings for recruiting organizations are discussed

Comparing the Police and Citizen Views On Biased Policing

Bias‐based policing is an issue that police departments all over the country are addressing. While police engage the public in many ways, traffic stops are possibly the most common way. This research project sought to broaden the approach to assessing bias‐based policing beyond traffic stop data by surveying the officers and the citizens to compare the views of both of these groups. Our research found interesting comparisons that we discuss in this paper. These issues between the two groups are important to resolving the issues associated with bias‐based policing