Clastogenic and aneuploidogenic effects of cigarette smoke condensate, mitomycin C and vincristine sulfate.

Immunofluorescent staining of kinetochores in micronuclei (MN) of cytochalasin-B-blocked cells was used to distinguish between clastogenic and aneuploidogenic effects of cigarette smoke condensate (CSC), mitomycin C (MMC) and vincristine sulfate (VS) in Chinese hamster lung V79 cells by using an anti-kinetochore antibody. Within the base-line micronucleated cells (2%), 50 to 58% contained kinetochore-positive (KC+) MN. MMC induced a significantly higher number of MN compared to the controls (P < 0.01), and the majority of micronucleated cells (77% at 0.08 microgram/ml) contained kinetochore-negative (KC-)MN. In contrast, VS induced a large number of MN (P < 0.01) but most of the micronucleated cells contained KC+ MN (93% at 0.08 microgram/ml). Cigarette smoke condensate (CSC) induced both KC+ (P < 0.01) and KC-(P < 0.05) MN suggesting the presence of both clastogenic and aneuploidogenic agents. However, the higher frequency of KC+ than KC- micronucleated cells suggests a stronger aneuploidogenic effect of CSC.