Soluble adenylyl cyclase defines a nuclear cAMP microdomain in keratinocyte hyperproliferative skin diseases.

Cyclic adenosine monophosphate (cAMP) is a nearly ubiquitous signaling molecule important for numerous signaling pathways in human skin. We studied a novel class of mammalian adenylyl cyclase, the soluble adenylyl cyclase (sAC). We examined sAC localization in normal human skin and found it to be present in keratinocytes, melanocytes, mononuclear cells, eccrine ducts, and nerves. In normal skin, sAC keratinocyte staining was evenly distributed throughout the cell. However, in certain hyperproliferative disorders of the skin, including psoriasis, verruca vulgaris, and SCCIS on sun-damaged skin, sAC keratinocyte staining was predominantly nuclear. In contrast, in other hyperproliferative disorders, such as basal cell carcinoma, sAC staining was similar to normal human skin. Using a model of epithelial differentiation, we established that sAC migrates into the nucleus when differentiated cells are induced to reenter the cell cycle. Previous work had determined that nuclear sAC activates the cAMP-response-element-binding (CREB) transcription factor, and we found that in psoriasis lesions, nuclear sAC occurs concomitantly with activation of CREB. Hence, sAC may play a role in the pathogenesis of certain hyperproliferative skin disorders via modulation of gene expression.

CXCL12 and CXCR4 in adenocarcinoma of the lung: association with metastasis and survival.

OBJECTIVES: Although the chemokine CXCL12 and its receptor CXCR4 have been implicated in metastasis of non-small cell lung carcinoma, the prognostic significance of these molecules is poorly defined. This study aimed to determine whether expression of these molecules is associated with clinicopathologic features and disease-free survival in non-small cell lung carcinoma. METHODS: Immunohistochemical staining for CXCL12 and CXCR4 was performed on 154 primary non-small cell lung carcinomas. Staining intensity was compared with tumor histotype, TNM stage, and disease-free survival; correlation was assessed by using the Fisher's exact test, and Kaplan-Meier and Cox multivariate proportional hazards regression analysis. RESULTS: Intense CXCL12 immunostaining was associated with nodal metastasis, although no difference in survival was observed. The prognostic relevance of CXCR4 was dependent on its subcellular location: in univariate analysis intense nuclear staining was significantly associated with lower T classification and improved disease-free survival in patients with adenocarcinoma, whereas cytomembranous staining was associated with distant metastasis and decreased disease-free survival. On multivariate analysis, cytomembranous CXCR4 expression conferred a significantly worse disease-free survival (relative risk, 2.8; 95% confidence interval, 1.4-5.7; P = .004). CONCLUSIONS: Cytomembranous expression of the chemokine receptor CXCR4 in adenocarcinoma of the lung is an independent risk factor associated with worse disease-free survival, whereas nuclear staining confers a survival benefit. These findings are consistent with a model in which CXCR4 promotes tumor cell proliferation and metastasis when present in the cytoplasm or cell membrane, whereas localization of this molecule in the nucleus prevents it from exerting these effects.