Tumor Growth Inhibition by Radiation and CCR2/CCR5 Antagonist

A general tumor protocol was established where 1 x 10⁵ tumor cells were injected intramuscularly in the left legs of female C57BL/6J or BALB/cJ mice. Mice were treated locally with radiotherapy (RT) 7 days after tumor cell injection using a 3200 Curie-sealed ¹³⁷Cesium source that operates at roughly 1.90 Gy/min. Jigs were constructed and designed to specifically treat the tumor-bearing leg with 15 Gy radiation [2 (link)]. This source and the collimators used are calibrated periodically to ensure equal distribution of radiation. Standard calipers were used to measure tumor growth as described previously [53 (link)]. Tumor-bearing mice were administered 15 mg/kg of a CCR2/CCR5 antagonist (named CVC, Tobira Therapeutics, CA) [54 (link), 55 (link)] or vehicle control (40% Hydroxypropyl-beta-cyclodextrin [Acros Organics] & solutol HS15 [Sigma] in sterile water) subcutaneously (s.c.) 1X/day starting 2 days before RT for the indicated amount of time. CD8+ T cells were depleted by treating mice with 200 ug of anti-CD8 (clone 53-6.7) i.p. every 3 days beginning 4 days post-tumor inoculation. Rat IgG was used as a control in anti-CD8 experiments and did not affect tumor growth when compared to mice that did not receive rat IgG (data not shown).