N-methyl-D-aspartate (NMDA) receptors contribute to many brain functions. We studied the effect of forebrain-targeted overexpression of the NMDA receptor subunit NR2B on the response of mice to tissue injury and inflammation. Transgenic mice exhibited prominent NR2B expression and enhanced NMDA receptor-mediated synaptic responses in two pain-related forebrain areas, the anterior cingulate cortex and insular cortex, but not in the spinal cord. Although transgenic and wild type mice were indistinguishable in tests of acute pain, transgenic mice exhibited enhanced responsiveness to peripheral injection of two inflammatory stimuli, formalin and complete Freund's adjuvant. Genetic modification of forebrain NMDA receptors can therefore influence pain perception, which suggests that forebrain-selective NMDA receptor antagonists, including NR2B-selective agents, may be useful analgesics for persistent pain.

Purpose: Elevated cyclin D1 in human pancreatic cancer correlates with poor prognosis.Because pancreatic cancer is invariably resistant to chemotherapy, the goal of this study was to examine whether the drug resistance of pancreatic cancer cells is in part attributed to cyclin D1 overexpression. Experimental Design: Stable overexpression and small interfering RNA (siRNA)^mediated knockdown of cyclin D1 were done in the newly established Ela-myc pancreatic tumor cell line. Cisplatin sensitivity of control, overexpressing, and siRNA-transfected cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, clonogenic, and apoptotic assays [DNA fragmentation, sub-G 1 , and poly(ADP-ribose) polymerase cleavage analysis]. The role of nuclear factor-nB and apoptotic proteins in cyclin D1-mediated chemoresistance was examined by EMSA and Western blotting, respectively. Results: Overexpression of cyclin D1in Ela-myc pancreatic tumor cells promoted cell proliferation and anchorage-independent growth. Moreover, cyclin D1^overexpressing cells exhibited significantly reduced chemosensitivity and a higher survival rate upon cisplatin treatment, as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and clonogenic assays, respectively. Although overexpression of cyclin D1 rendered cells more resistant to cisplatininduced apoptosis, siRNA-directed suppression of cyclin D1 expression resulted in enhanced susceptibility to cisplatin-mediated apoptosis. The attenuation of cisplatin-induced cell death in cyclin D1^overexpressing cells was correlated with the up-regulation of nuclear factor-nB activity and maintenance of bcl-2 and bcl-xl protein levels. Conclusions: These results suggest that overexpression of cyclin D1 can contribute to chemoresistance of pancreatic cancer cells because of the dual roles of cyclin D1 in promoting cell proliferation and in inhibiting drug-induced apoptosis.Human pancreatic cancer is an aggressive disease that currently has no viable treatment. This is mainly due to late diagnosis and resistance of the cancer cells to conventional chemotherapeutic agents (1 -3). Previous studies have addressed the clinical relevance of cyclin D1 in pancreatic cancer (4 -7). A significant proportion of pancreatic cancer cases show overexpression of the cyclin D1 gene (5, 8). Furthermore, increased cyclin D1 expression is associated with poor prognosis (5) and decreased postoperative patient survival (8). However, the molecular mechanisms underlying the poor prognostic value of elevated cyclin D1 in pancreatic cancer remain unknown.The proto-oncogenic function of cyclin D1 has been attributed in part to its role in promoting cell cycle progression. Cyclin D1 is a key cell cycle regulator of the G 1 to S phase progression (9, 10). The binding of cyclin D1 to cyclindependent kinase (cdk4 or cdk6) leads to the phosphorylation of retinoblastoma protein (pRb) subsequently triggering the release of E2F transcription factors to allow transcription of genes required f...

Neutrophil transmigration into tissue is a multiple-step process that results from a coordinated rearrangement of the cytoskeleton and adhesion complexes. Assembly and disassembly of actin and adhesion structures dictate motility behavior, while polarity and gradient sensing provide directionality to the cell movement. Here, using mice deficient in the CDC42 regulator CDC42 GTPase-activating protein (CDC42GAP), we demonstrate that CDC42 activity separately regulates neutrophil motility and directionality. CDC42GAP ؊/؊ neutrophils showed increased motility, while directed migration was defective. Podosome-like structures present at the leading edge in wild-type neutrophils were significantly reduced in CDC42GAP ؊/؊ cells. CDC42GAP ؊/؊ neutrophils also showed increased lateral and tail filopodia-like formation, and excess membrane protrusions. We further suggest that CDC42GAP-mediated extracellular signal-regulated kinase (ERK) activity regulates motility associated with podosome-like structures at the cell leading edge, while CDC42GAP-induced p38 MAPK phosphorylation regulates directed migration by antagonizing filopodia assembly. Overall, this study reveals that CDC42 activity regulates both motility and directionality in neutrophils, but via distinct mitogen-activated protein kinase ( IntroductionNeutrophils are critical in the inflammatory process. The recruitment of neutrophils to sites of inflammation requires a series of highly regulated adhesive and chemotactic events. These cellular activities result from the activation of signals from various receptors, including adhesion molecules such as selectins and integrins, and chemokine receptors. Failure to regulate any of these events may lead to abnormal innate immune responses, including immunodeficiency or aberrant inflammatory reactions. Although the process of neutrophil extravasation has been well studied, the intracellular molecular events that ultimately regulate these processes still remain to be understood in detail, particularly in physiologic settings.Cell migration is a multiple-step process that results from a coordinated rearrangement of the cytoskeleton and adhesion complexes. 1 Upon chemoattractant stimulation, cells polarize and form lamellipodia containing F-actin at the leading edge oriented toward the source of stimulation and a contractile uropod. The lamellipodia are stabilized to the substratum by the assembly of adhesion complexes, which mature into focal adhesions. These complexes serve as traction forces necessary for the translocation of the cell body. Completion of cell migration requires actin disruption to allow both adhesion complex turnover at the leading edge and retraction of the tail. Thus, the cytoskeleton, through assembly and disassembly of F-actin and adhesion structures, is believed to dictate motility behavior, while polarity and gradient sensing give direction to the cell movement.The key integrators of signals emanating from chemokine receptors and integrin molecules that coordinate these processes are members of the...