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Adenosine receptors (ADORs) are G protein-coupled purinoceptors that have several functions including regulation of chloride secretion via cystic fibrosis transmembrane conductance regulator (CFTR) in human airway and kidney. We cloned an ADOR from Squalus acanthias (shark) that likely regulates CFTR in the rectal gland. Phylogenic and expression analyses indicate that elasmobranch ADORs are nonolfactory and appear to represent extant predecessors of mammalian ADORs. We therefore designate the shark ADOR as the A 0 receptor. We coexpressed A 0 with CFTR in Xenopus laevis oocytes and characterized the coupling of A 0 to the chloride channel. Two-electrode voltage clamping was performed, and current-voltage ( I-V ) responses were recorded to monitor CFTR status. Only in A 0 - and CFTR-coinjected oocytes did adenosine analogs produce a significant concentration-dependent activation of CFTR consistent with its electrophysiological signature. A pharmacological profile for A 0 was obtained for ADOR agonists and antagonists that differed markedly from all mammalian ADOR subtypes [agonists: R-phenyl-isopropyl adenosine (R-PIA) > S-phenyl-isopropyl adenosine (S-PIA) > CGS21680 > N 6 -cyclopentyladenosine (CPA) > 2-chloroadenosine (2ClAdo) > CV1808 = N 6 -[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)ethyl]adenosine (DPMA) > N -ethyl-carboxyl adenosine (NECA); and antagonists: 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) > PD115199 > 1,3-dimethyl-8-phenylxanthine (8PT) > CGS15943]. Structures of human ADORs permitted a high-confidence homology model of the shark A 0 core that revealed unique structural features of ancestral receptors. We conclude that 1 ) A 0 is a novel and unique adenosine receptor ancestor by functional and structural criteria; 2 ) A 0 likely activates CFTR in vivo, and this receptor activates CFTR in oocytes, indicating an evolutionary coupling between ADORs and chloride secretion; and 3 ) A 0 appears to be a nonolfactory evolutionary ancestor of all four mammalian ADOR subtypes.

Unlabelled: Chemotherapy is currently the treatment of choice for patients with high-risk metastatic breast cancer. Clinical response is determined after several cycles of chemotherapy by changes in tumor size as assessed by conventional imaging procedures including CT, MRI, plain film radiography, or ultrasound. The aim of this study was to evaluate the use of sequential 18F-FDG PET to predict response after the first and second cycles of standardized chemotherapy for metastatic breast cancer., Methods: Eleven patients with 26 metastatic lesions underwent 31 (18)F-FDG PET examinations (240-400 MBq of 18F-FDG; 10-min 2-dimensional emission and transmission scans). Clinical response, as assessed by conventional imaging after completion of chemotherapy, served as the reference. 18F-FDG PET images after the first and second cycles of chemotherapy were analyzed semiquantitatively for each metastatic lesion using standardized uptake values (SUVs) normalized to patients' blood glucose levels. In addition, whole-body 18F-FDG PET images were viewed for overall changes in the 18F-FDG uptake pattern of metastatic lesions within individual patients and compared with conventional imaging results after the third and sixth cycles of chemotherapy., Results: After completion of chemotherapy, 17 metastatic lesions responded, as assessed by conventional imaging procedures. In those lesions, SUV decreased to 72% +/- 21% after the first cycle and 54% +/- 16% after the second cycle, when compared with the baseline PET scan. In contrast, 18F-FDG uptake in lesions not responding to chemotherapy (n = 9) declined only to 94% +/- 19% after the first cycle and 79% +/- 9% after the second cycle. The differences between responding and nonresponding lesions were statistically significant after the first (P = 0.02) and second (P = 0.003) cycles. Visual analysis of 18F-FDG PET images correctly predicted the response in all patients as early as after the first cycle of chemotherapy. As assessed by 18F-FDG PET, the overall survival in nonresponders (n = 5) was 8.8 mo, compared with 19.2 mo in responders (n = 6)., Conclusion: In patients with metastatic breast cancer, sequential 18F-FDG PET allowed prediction of response to treatment after the first cycle of chemotherapy. The use of 18F-FDG PET as a surrogate endpoint for monitoring therapy response offers improved patient care by individualizing treatment and avoiding ineffective chemotherapy.

Members of the Fos family of AP-1 transcription factors (c-Fos, FosB, FosB2, Fra-1 and Fra-2) are able to form dimers with Jun proteins which bind to the regulatory sequences of target genes. As many proteases involved in tumor invasion are AP-1-regulated, we assumed that Fos family members might be important for invasion of mammary carcinomas. Therefore, we performed transient transfections with expression vectors for c-Fos, FosB, FosB2, Fra-1 and Fra-2, followed by matrigel invasion assays. Fra-1 transfection resulted in a 2-4-fold increase of invasive cells in both cell lines. In a less degree, the invasive potential of MDA-MB231 cells was stimulated by Fra-2, whereas MCF7 invasion was enhanced by c-Fos and FosB. By double-labelling immunocytochemistry, PAI-1 up-regulation was observed in cells transfected with c-Fos, Fra-1 and Fra-2 expression vectors, whereas MMP1 and MMP9 expression was not affected. Results of cotransfection with a MMP9 promoter construct and AP-1 expression vectors do not indicate a direct up-regulation of MMP9 expression by Fos proteins except a positive effect of c-Fos in MCF7 cells. In parallel, expression of Fos family members as determined by Western Blot analysis in 75 mammary carcinomas was correlated with MMP1, MMP9, PAI-1 and uPAR protein levels in the tumors. Interestingly, high FosB levels were significantly associated with MMP1 overexpression, whereas expression of c-Fos and phosphorylated Fra-1 correlated with MMP9 protein levels. Strong Fra-2 expression correlated with high levels of MMP9, PAI-1, the uPA/PAI-1 complex and early recurrence. These data indicate that Fos proteins, especially Fra-1, c-Fos and Fra-2, might be involved in invasion of breast cancer cells., (Copyright 2004 Kluwer Academic Publishers)