Extensive documentation has validated the role of UV irradiation as a tumor initiator and promoter, inducing both squamous and basal cell carcinomas. Human epidermis is a tissue which undergoes active metabolism of arachidonic acid to prostaglandins which is regulated by the action of prostaglandin H synthase (also known as cyclooxygenase). One mechanism for the promotional activity of UV light may involve its ability to induce prostaglandin formation. Work in our laboratory has demonstrated that acute exposure of human keratinocytes to UVB irradiation results in increased production of prostaglandin E2 (PGE2). When cultured human keratinocytes were examined after irradiation with 30 mJ/cm2 UVB in vitro, Western blot analysis showed a 6-fold increase in COX-2 protein which was evident at 6 h and peaked 24 h after irradiation. Furthermore, when human subjects were irradiated on sun-protected skin with up to four times their minimal erythema dosage (MED) and biopsied 24 h later, upregulation of COX-2 protein expression was observed via immunofluorescence microscopy. RNAase protection assays supported this observation, showing induction of COX-2 message which peaked at approximately 12 h following irradiation in vitro. Furthermore, human squamous cell carcinoma biopsies exhibited strongly enhanced staining for COX-2 protein via immunohistochemistry and Western analysis when compared to normal non-sun-exposed control skin. Together, these data demonstrate acute upregulation of COX-2 via UVB irradiation and suggest the need for further studies of COX-2 expression as a potential pharmacological target mediating human skin tumor development.

The mitogen-activated protein kinase (MAPK) cascade is believed to function as an important regulator of prostaglandin biosynthesis. Previously we reported that interleukin-1␤ induces activation of JNK/SAPK and p38 MAPK with concomitant up-regulation of cyclooxygenase (Cox)-2 expression and prostaglandin E 2 (PGE 2 ) synthesis. Our experiments demonstrate that overexpression of ⌬MEKK1 (a constitutively active truncation mutant of MEKK1 containing the C-terminal 324 amino acids) increases Cox-2 expression and PGE 2 production which is completely blocked by SC68376, a pharmacologic inhibitor of p38 MAPK. ⌬MEKK1 overexpression results in activation of both c-Jun N-terminal kinases/ extracellular signal-regulated kinases (JNK/SAPK) and p38 MAPK. Furthermore, activation of MEKK1 increases SEK1/MKK4 but not MKK3 or MKK6 activity. These findings suggest that MEKK1 3 SEK1/MKK4 may function as an upstream kinase capable of activating both p38 MAPK and JNK/SAPK with subsequent induction of Cox-2 expression and PGE 2 production. We also found that overexpression of the constitutively active form of SEK1 (SEK1-ED) increases both p38 MAPK and JNK/ SAPK phosphorylation, and increases PGE 2 production and Cox-2 expression. By comparison, overexpression of the dominant negative form of SEK1 (SEK1-AL) decreases the phosphorylation of both p38 MAPK and JNK/ SAPK and reduces Cox-2 expression. Together, this data suggests a potential role for the MEKK1 3 SEK1/MKK4 3 p38 MAPK 33 Cox-2 cascade linking members of the MAPK pathway with prostaglandin biosynthesis.Prostaglandins are ubiquitous compounds involved in various homeostatic and inflammatory processes throughout the body. They are formed by the combined action of a phospholipase A 2 (PLA 2 ) 1 which liberates arachidonic acid from the sn-2 position of cellular membrane phospholipids and the cyclooxygenase (Cox) which converts arachidonic acid to the endoperoxide intermediate PGH 2 . PGH 2 is subsequently converted to prostaglandins by the action of cell-specific synthases (1). There are two cyclooxygenase enzymes which have been identified (60% homology), Cox-1 and Cox-2. Cox-1 is constitutively expressed in most tissues and mediates physiologic responses such as regulation of renal and vascular homeostasis and cytoprotection of the stomach. By comparison Cox-2 is primarily considered an inducible immediate-early gene product whose synthesis can be up-regulated by mitogenic or inflammatory stimuli including: tumor promoters (2), IL-1␤ (3), endotoxins (4), platelet-derived growth factor (5), and serum (6).The physiological role of the cyclooxygenase has been the topic of much interest. Cyclooxygenases are the main therapeutic target for non-steroidal anti-inflammatory drugs which exhibit their antipyretic, analgesic, and anti-inflammatory effects in humans via inhibition of prostaglandin biosynthesis (7). Non-steroidal anti-inflammatory drugs have been effective in the reduction of inflammatory symptoms in carrageenan-induced rat paw inflammation models (8) and in the reduced in...

Recent advances in neurobiology and clinical medicine have established that the fetus and newborn may experience acute, established, and chronic pain. They respond to such noxious stimuli by a series of complex biochemical, physiologic, and behavioral alterations. Studies have concluded that controlling pain experience is beneficial with respect to short-term and perhaps long-term outcomes. Yet, pain-control measures are adopted infrequently because of unresolved scientific issues and lack of appreciation for the need for control of pain and its long-term sequelae during the critical phases of neurologic maturation in the preterm and term newborn. The neonatal pain-control group, as part of the Newborn Drug Development Initiative (NDDI) Workshop I, addressed these concerns. The specific issues addressed were (1) management of pain associated with invasive procedures, (2) provision of sedation and analgesia during mechanical ventilation, and (3) mitigation of pain and stress responses during and after surgery in the newborn infant. The cross-cutting themes addressed within each category included (1) clinical-trial designs, (2) drug prioritization, (3) ethical constraints, (4) gaps in our knowledge, and (5) future research needs. This article provides a summary of the discussions and deliberations. Full-length articles on procedural pain, sedation and analgesia for ventilated infants, perioperative pain, and study designs for neonatal pain research were published in Clinical Therapeutics (June 2005).www.pediatrics.org/cgi

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Abstract. There have been some successes in qualifying biomarkers and applying them to drug development and clinical treatment of various diseases. A recent success is illustrated by a collaborative effort among the US Food and Drug Administration, the European Medicines Agency, and the pharmaceutical industry to provide a set of seven preclinical kidney toxicity biomarkers for drug development. Other successes include, but are not limited to, clinical biomarkers for cancer treatment and clinical management of heart transplant patients. The value of fully qualified surrogate endpoints in facilitating successful drug development is undisputed, especially for diseases in which the traditional clinical outcome can only be assessed in large, multi-year trials. Emerging biomarkers, including chemical genomic or imaging biomarkers, and measurement of circulating tumor cells hold great promise for early diagnosis of disease and as prognostic tests for managing treatment of chronic diseases such as osteoarthritis, Alzheimer disease, cardiovascular disease, and cancer. To advance the success of treating and managing these diseases, efforts are needed to establish the temporal relationship between changes in inflammatory or imaging biomarkers with the progression of the chronic disease, and in the case of cancer, between the extent of circulating cancer cells and tumor progression or remission.

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The thromhin receptor is a G protein-coupled receptor, hut the G proteins functionally coupled to this receptor in human platelets are not yet definitively identified. Thrombin stimulation of platelets leads to phospholipase C-mediated increases in intracellular calcium, and previous studies have suggested that the thrombin receptor is coupled to members of the G, family. We now demonstrate direct GTPase activation by tbrombin receptor activation peptide (TRAP) in human platelet membranes, and specific inhibition of TRAP-activated GTPase by antibodies to G,. These data demonstrate functional coupling of the thrombin receptor to a member of the G, family.

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