Chemokine receptors in head and neck cancer: association with metastatic spread and regulation during chemotherapy.

Head and neck carcinomas are histologically and clinically heterogeneous. While squamous cell carcinomas (SCC) are characterized by lymphogenous spread, adenoid cystic carcinomas (ACC) disseminate preferentially hematogenously. To study cellular and molecular mechanisms of organ-specific metastasis, we used SCC and ACC cell lines and tumor tissues, obtained from patients with primary or metastatic disease. Comprehensive analysis at the mRNA and protein level of human chemokine receptors showed that SCC and ACC cells exhibited distinct and nonrandom expression profiles for these receptors. SCC predominantly expressed receptors for chemokines homeostatically expressed in lymph nodes, including CC chemokine receptor (CCR) 7 and CXC chemokine receptor (CXCR)5. No difference in expression of chemokine receptors was seen in primary SCC and corresponding lymph node metastases. In contrast to SCC, ACC cells primarily expressed CXCR4. In chemotaxis assays, ACC cells were responsive to CXCL12, the ligand for CXCR4. Exposure of ACC cells to cisplatin resulted in upregulation of CXCR4 on the cell surface, which was repressed by the transcriptional inhibitor, alpha-amanitin. Treatment of ACC cells with CXCL12 resulted in the activation of Akt and ERK1/2 pathways. Furthermore, CXCL12 suppressed the rate of apoptosis induced by cisplatin in ACC cells, suggesting that signaling via CXCR4 may be part of a tumor cell survival program. Discrimination of the chemokine receptor profile in SCC and ACC in vitro and in tissues provided insights into their distinct biologic and clinical characteristics as well as indications that chemokine receptors might serve as future therapeutic targets in these malignancies.

Ultraviolet radiation-induced injury, chemokines, and leukocyte recruitment: An amplification cycle triggering cutaneous lupus erythematosus.

OBJECTIVE: To investigate the activation and recruitment pathways of relevant leukocyte subsets during the initiation and amplification of cutaneous lupus erythematosus (LE). METHODS: Quantitative real-time polymerase chain reaction was used to perform a comprehensive analysis of all known chemokines and their receptors in cutaneous LE lesions, and the cellular origin of these chemokines and receptors was determined using immunohistochemistry. Furthermore, cytokine- and ultraviolet (UV) light-mediated activation pathways of relevant chemokines were investigated in vitro and in vivo. RESULTS: In the present study, we identified the CXCR3 ligands CXCL9 (interferon-gamma [IFNgamma]-induced monokine), CXCL10 (IFNgamma-inducible protein 10), and CXCL11 (IFN-inducible T cell alpha chemoattractant) as being the most abundantly expressed chemokine family members in cutaneous LE. Expression of these ligands corresponded with the presence of a marked inflammatory infiltrate consisting of mainly CXCR3-expressing cells, including skin-homing lymphocytes and blood dendritic cell antigen 2-positive plasmacytoid dendritic cells (PDCs). Within cutaneous LE lesions, PDCs accumulated within the dermis and were activated to produce type I IFN, as detected by the expression of the IFNalpha-inducible genes IRF7 and MxA. IFNalpha, in turn, was a potent and rapid inducer of CXCR3 ligands in cellular constituents of the skin. Furthermore, we demonstrated that the inflammatory CXCR3 ligands cooperate with the homeostatic chemokine CXCL12 (stromal cell-derived factor 1) during the recruitment of pathogenically relevant leukocyte subsets. Moreover, we showed that UVB irradiation induces the release of CCL27 (cutaneous T cell-attracting chemokine) from epidermal compartments into dermal compartments and up-regulates the expression of a distinct set of chemokines in keratinocytes. CONCLUSION: Taken together, our data suggest an amplification cycle in which UV light-induced injury induces apoptosis, necrosis, and chemokine production. These mechanisms, in turn, mediate the recruitment and activation of autoimmune T cells and IFNalpha-producing PDCs, which subsequently release more effector cytokines, thus amplifying chemokine production and leukocyte recruitment, finally leading to the development of a cutaneous LE phenotype.

Pharmacological characterization of the chronic constriction injury model of neuropathic pain.

The chronic constriction injury model is a rat model of neuropathic pain based on a unilateral loose ligation of the sciatic nerve. The aim of the present study was to test its sensitivity to various clinically validated and experimental drugs. Mechanical allodynia and thermal hyperalgesia developed within one week post-surgery and were reliably present for at least 7 weeks. Mechanical allodynia was strongly attenuated by morphine (minimal effective dose in brackets: 8 mg/kg, p.o.) and the cannabinoids Delta9-tetrahydrocannabinol (3 mg/kg, p.o.) and (-)-cis-3-[2-hydroxy-4(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl) cyclohexanol (CP 55,940; 0.05 mg/kg, i.p.), and weakly/moderately attenuated by the anticonvulsants gabapentin (50 mg/kg, i.p.) and carbamazepine (32 mg/kg, i.p.), the muscle relaxant baclofen (3 mg/kg, i.p.), and the adenosine kinase inhibitor 4-amino-5-(3-bromophenyl)-7-(6-morpholino-pyridin-3-yl)pyrido[2,3-d]pyrimidine (ABT-702; 30 mg/kg, i.p.). Thermal hyperalgesia was strongly attenuated by morphine (16 mg/kg, p.o.), Delta9-tetrahydrocannabinol (6 mg/kg, p.o.), CP 55,940 (0.025 mg/kg, i.p.), carbamazepine (32 mg/kg, i.p.) and the antidepressant amitriptyline (32 mg/kg, p.o.), and weakly/moderately attenuated by gabapentin (50 mg/kg, i.p.), the anti-inflammatory cyclooxygenase-2 inhibitor rofecoxib (30 mg/kg, i.p.) and the adenosine A1 receptor positive allosteric modulator 2-amino-4,5,6,7-tetrahydrobenzo(b)thiophen-3-yl 4-chlorophenylmethanone (T62; 30 mg/kg, i.p.). Both symptoms were hardly or not affected by the nonselective N-methyl-d-aspartate receptor antagonists ketamine and dizocilpine, and the N-methyl-d-aspartate receptor NR2B-selective antagonists ifenprodil and R-(R*,S*)-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenyl-methyl)-1-piperidine propranol (Ro 25-6981). The finding that mechanical allodynia and/or thermal hyperalgesia are attenuated by various established compounds further supports the validity of the chronic constriction injury model for the study of neuropathic pain and its use for the identification of novel treatments.