title: Inhibition of lung colonization at two different steps in the metastatic sequence.
abstract: Two immunomodulatory protocols were evaluated for their ability to inhibit lung colonization by mouse mammary tumor line 4T07. Preimmunization with tumor cells or pretreatment with poly I:C were equally effective at inhibiting lung colonization but a clonogenic tumor cell assay demonstrated that the treatments reduced tumor cell burden at different steps during the metastatic process. Poly I:C pretreatment accelerated tumor cell clearance based on the recovery of clonogenic tumor cells from lungs dispersed within 6 h post-arrest. Preimmunization inhibited the subsequent replication of tumor cells which survived and established in the lung, as indicated by the expansion of clonogenic cell numbers between 1 day and 7 days post-arrest. Histologic examination of serial sections of lungs demonstrated that very few (6%) of the tumor cells were extravascular 6 h post-tumor cell injection. By 24 h and 168 h the percentages of tumor cells which were extravascular had increased to 62% and 86%, respectively. Thus, poly I:C pretreatment appears to enhance killing of tumor cells prior to extravasation, whereas preimmunization appears to inhibit tumor cells after extravasation.
authors.affiliation: E. Walter Albachten Department of Immunology, Michigan Cancer Foundation, Detroit 48201.
authors.forename: C J
authors.initials: CJ
authors.lastname: Aslakson
authors.forename: D
authors.initials: D
authors.lastname: McEachern
authors.forename: D H
authors.initials: DH
authors.lastname: Conaway
authors.forename: F R
authors.initials: FR
authors.lastname: Miller
mesh_terms: D000818:Animals; D002455:Cell Division; D005260:Female; D007114:Immunization; D008168:Lung / Q000473:pathology; D008175:Lung Neoplasms / Q000556:secondary; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D009362:Neoplasm Metastasis; D011070:Poly I-C / Q000494:pharmacology
chemical_list: D011070:Poly I-C