title: Hypernociceptive responses following the intratibial inoculation of RM1 prostate cancer cells in mice.
abstract: BACKGROUND
  Pain due to bone metastases of prostatic origin is a relevant clinical issue. We study here the nociceptive responses obtained in mice receiving the intratibial inoculation of RM1 prostate cancer cells.
  
  
  METHODS
  10(2) -10(5) RM1 cells were inoculated to C57BL/6 mice and tumor development was analysed histologically and with luciferase-expressing RM1 cells. Spinal astroglial (GFAP) or microglial (Iba-1) expression was assessed with immunohistochemical methods and hypernociception was measured by the unilateral hot plate, the paw pressure and the von Frey tests. The analgesic effect of morphine, zoledronic acid or the CCR2 antagonist RS504393 was measured. Levels of the chemokines CCL2, CCL3, and CCL5 were determined by ELISA.
  
  
  RESULTS
  The inoculation of 10(3) RM1 cells induced tumoral growth in bone with a mixed osteoclastic/osteoblastic pattern and evoked astroglial, but not microglial, activation in the spinal cord. Hyperalgesia and allodynia were already established four days after inoculation and dose-dependently inhibited by the s.c. administration of morphine (1-5 mg/kg) or zoledronic acid (1-3 mg/kg). CCL2 and CCL5, but not CCL3, were released by RM1 cells in culture whereas only an increased presence of CCL2 was found in bone tumor homogenates. The administration of the CCR2 antagonist RS504393 (0.3-3 mg/kg) inhibited RM1 induced thermal hyperalgesia without modifying mechanical allodynia.
  
  
  CONCLUSIONS
  The intratibial inoculation of RM1 cells in immunocompetent mice induces hypernociceptive responses and can be useful to perform studies of bone cancer induced pain related to androgen-independent prostate cancer. The antinociceptive role derived from the blockade of the CCR2 chemokine receptors is further envisaged.
authors.affiliation: Laboratorio de Farmacología, Facultad de Medicina, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo, Asturias, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Llorián-Salvador
authors.forename: Marta
authors.initials: M
authors.lastname: Pevida
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Fernández-García
authors.forename: Ana
authors.initials: A
authors.lastname: Lastra
authors.forename: Alvaro
authors.initials: A
authors.lastname: Obaya
authors.forename: Santiago
authors.initials: S
authors.lastname: Cal
authors.forename: Agustín
authors.initials: A
authors.lastname: Hidalgo
authors.forename: Luis
authors.initials: L
authors.lastname: Menéndez
authors.forename: Ana
authors.initials: A
authors.lastname: Baamonde
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000556:secondary*; D002135:Calcium-Binding Proteins; D045744:Cell Line, Tumor; D018925:Chemokines / Q000378:metabolism; D004164:Diphosphonates / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005904:Glial Fibrillary Acidic Protein; D006930:Hyperalgesia / Q000188:drug therapy / Q000503:physiopathology*; D007093:Imidazoles / Q000494:pharmacology; D007150:Immunohistochemistry; D008297:Male; D008810:Mice, Inbred C57BL; D008840:Microfilament Proteins; D009020:Morphine / Q000494:pharmacology; D009368:Neoplasm Transplantation; D009419:Nerve Tissue Proteins; D059226:Nociceptive Pain / Q000188:drug therapy / Q000503:physiopathology*; D011471:Prostatic Neoplasms / Q000473:pathology*; D054390:Receptors, CCR2 / Q000378:metabolism; D013116:Spinal Cord / Q000473:pathology; D013977:Tibia / Q000473:pathology*; D000077211:Zoledronic Acid
chemical_list: C491049:Aif1 protein, mouse; D002135:Calcium-Binding Proteins; D018925:Chemokines; D004164:Diphosphonates; D005904:Glial Fibrillary Acidic Protein; D007093:Imidazoles; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D054390:Receptors, CCR2; C528900:glial fibrillary astrocytic protein, mouse; D000077211:Zoledronic Acid; D009020:Morphine
keywords: bone cancer-induced pain; chemokine CCL2; morphine; mouse; prostate bone metastasis; zoledronic acid