The human ELAV(embryonic lethal abnormal vision)-like protein HuR stabilizes a certain group of cellul ar mHNAs that contain AU- rich elements in their 3’ - untranslated region , To test the significance of HuR in carcinogenesis of head and neck squamous cell carcinomas(HNSCCs), we have investigated HuH expression from 32 benign epithelial lesions , 14 prema lignant epitheli al lesions and 80 HNSCCs, There were two different staining patterns of HuR in HNSCCs : nuclear expression was seen in 78 7% (63 of 80) 01' cases; and an additional cyto plasmic expression was seen in 28, 7%(23 of 80) 01 cases, Nuclear expression of HuR was s ignificantly increased in premalignant lesions and HNSCCs, whereas increased cytoplasπli c expression of HuR was only observed in HNSCCs Cytoplasmic HuR expression was significantly increased in pa tients of HNSCC younger than 60 yea rs , Al though there was no significant correlation between a natomic s ites of HNSCCs and HuR express ion , cyto plasmic HuR expression was highly increased in HNSCCs of larynx, There was no significant co rrela tion between HuR expression and other clinicopathological parameters such as histological type‘ tumor s ize‘ 0 1' n odal s tatus , ln conclusion, this study s uggests that overexpression of HuR in HNSCCs may be part of a regula tory pathway tha t co ntro ls the mHNA stability 0 1' several important targets in carcinogenesis of HNSCCs

1,1- Bis(3’-indolyl)-l-(p-methoxyphenyl)methane (DIM- C- pPhOCH.3) is a methylenc - substituted diindolylmethanes (C-DIM) ana log that acti vates the orphan receptOl‘ nerve growth factor-induced-B (NGFI-B, Nur77) , RNA inteference studies with small inhibitory RNA for Nur77 demonstrate that DIM-C-pPhOCH:J induces Nur77-dependent and - independent apoptosis, and this study has focused on delineating the Nur77-independent proapoptotic pathways induced by the C-DIM analog DIM-C-pPhOCH3 induced caspase-dependent apoptosis in RKO colon cancer cells through decreased mitochondrial membrane potential which is accompanied by increased mitochondrial bax/bcl-2 ratios and release of cytochrome c into the cytosol DlM-C一pPhOCH.3 also induced phosphatidylinositol-3-kinase-dependent activation of early growth response gene-l whi ch, in turn, induced expression of the proapoptotic nonsteroidal anti-inflammatory drug- activated gene-l (NAG- l) in colon tumors in athyrnic nude mice bearing RKO cells as xenografts, DIM-C-pPhOCH.3 also activated the extrinsic apoptosis pathway through increased phosphorylation of c- jun N-terminal kinase which, in turn, activated C/EBP homologous transcription factor (CHOP) and death receptor 5 (DR5) , Thus, the effectiveness of DIM-C-pPhOCH.3 as a tumor growth inhibitor is through activation of Nur77-dependent and -independent pathways