CD437, a novel retinoid, causes cell cycle arrest and apoptosis in a number of cancer cells including human breast carcinoma (HBC) by utilizing an undefined retinoic acid receptor/retinoid X receptor-independent mechanism. To delineate mediators of CD437 signaling, we utilized a random antisense-dependent functional knockout genetic approach. We identified a cDNA that encodes ϳ130-kDa HBC cell perinuclear protein (termed CARP-1). Treatments with CD437 or chemotherapeutic agent adriamycin, as well as serum deprivation of HBC cells, stimulate CARP-1 expression. Reduced levels of CARP-1 result in inhibition of apoptosis by CD437 or adriamycin, whereas increased expression of CARP-1 causes elevated levels of cyclin-dependent kinase inhibitor p21

Skin biopsy is a minimally invasive procedure and has been used in the evaluation of non-myelinated, but not myelinated nerve fibres, in sensory neuropathies. We therefore evaluated myelinated nerves in skin biopsies from normal controls and patients with Charcot-Marie-Tooth (CMT) disease caused by mutations in myelin proteins. Light microscopy, electron microscopy and immunohistochemistry routinely identified myelinated dermal nerves in glabrous skin that appeared similar to myelinated fibres in sural and sciatic nerve. Myelin abnormalities were observed in all patients with CMT. Moreover, skin biopsies detected potential pathogenic abnormalities in the axolemmal molecular architecture previously undetected in human neuropathies. Finally, myelin gene expression at both mRNA and protein levels was evaluated by real-time PCR and immunoelectron microscopy. Peripheral myelin protein 22 (PMP22) was increased in CMT1A (PMP22 duplication) and decreased in patients with hereditary neuropathy with liability to pressure palsies (PMP22 deletion). Taken together, our data suggest that skin biopsy may in certain circumstances replace the more invasive sural nerve biopsy in the morphological and molecular evaluation of inherited and other demyelinating neuropathies.

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Focal adhesion kinase (FAK) regulates cell migration, proliferation, and apoptosis. FAK protein is reduced at the edge of migrating gut epithelial sheets in vitro, but it has not been characterized in restitutive gut mucosa in vivo. Here we show that FAK and activated phospho-FAK (FAK 397 ) immunoreactivity was lower in epithelial cells immediately adjacent to human gastric and colonic ulcers in vivo, but dramatically increased in epithelia near the ulcers, possibly reflecting stimulation by growth factors absent in vitro. Transforming growth factor (TGF)-␤, but not fibroblast growth factor, platelet-derived growth factor, or vascular endothelial growth factor, increased FAK levels in Caco-2 and IEC-6 cells. Epithelial immunoreactivity to TGF-␤ and phospho-Smad3 was also higher near the ulcers, varying in parallel with FAK. The TGF-␤ receptor antagonist SB431542 completely blocked TGF-␤-induced Smad2/3 and p38 activation in IEC-6 cells. SB431542 , the p38 antagonist SB203580 , and siRNA-mediated reduction of Smad2 and p38␣ prevented TGF-␤ stimulation of both FAK transcription and translation (as measured via a FAK promoter-luciferase construct). Survival and function of epithelial cells depends critically on interactions between the extracellular matrix and cell surface integrins. These interactions are mediated through focal adhesions, multicomponent juxtamembrane structures that lie at the convergence of integrin adhesion, signaling, and the cytoskeleton.1 Focal adhesion kinase (FAK) is an important nonreceptor tyrosine kinase within the focal adhesion complex.2 Originally described as being rapidly tyrosine phosphorylated on integrin-mediated cell-matrix adhesion, FAK is now known to be activated during epithelial cell motility and phosphorylated at both serine and tyrosine residues by various factors.3-5 Once localized to sites of transmembrane integrin receptor clustering, tyrosine-phosphorylated FAK plays a central role in signal transduction triggered by diverse extracellular signals 6 and represents a convergent point for synergistic interaction between signal pathways activated by growth factors and integrins.7 FAK binds to different signaling proteins via Src homology 2 (SH2) and SH3 recognition sites, acting as a scaffold and transmitting signals crucial to cell survival, motility, proliferation, and differentiation.8 FAK also regulates the cycle of focal contact formation and disassembly required for efficient cell movement and thus, mucosal restitution. 9Levels of FAK protein expression and/or activation have been correlated to phenotypic changes that affect cell differentiation and function, notably adhesion and migration, in a number of tissues. 10 -13 Targeted FAK deletion in vascular endothelial cells leads to apoptosis and aberrant cell movement whereas FAK overexpression results in increased angiogenesis.14,15 Total and activated FAK levels are also directly related to the state of differentiation in human colon cancer. 16 Induction of differentiation in dedifferentiated, rounded, detached Co...