Fig. 2.

Astrocyte stimulated the proliferation of tumor cells via soluble factors. a The normalized number of HARA-B cells increased according to the ratio of astrocytes to HARA-B cells and incubation time in co-culture treatment (HARA-B cells : astrocytes = 1:5, A5; HARA-B cells : astrocytes = 1:10, A10). b Culture medium from insert-culture of astrocytes with HARA-B cells (HARA-B cells : astrocytes = 1:10, A10) significantly increased the proliferation of tumor cells compared to the one without insert-culture medium (control). c H-ACM (HARA-B-stimulated astrocyte-conditioned medium), but not HCM (HARA-B-conditioned medium) nor ACM (astrocyte-conditioned medium) significantly increased the proliferation of tumor cells. The incubation time was 48 h (gray bars) and 72 h (black bars). Each value represents the mean ± SEM (n = 6). ** P < 0.01