Fig 2.

Histone deactylase inhibitor treatment increases MICA/B level and CIK anti-tumor effects in vivo in mouse tumor models. (A) Anti-MICA/B staining reveals up-regulation of surface expression of these ligands. UCI-101 tumors implanted subcutaneously into athymic nu-/nu- mice were treated with TSA (IP injection) and mice sacrificed after 24h. Sections were stained with anti-MICA/MICB antibody (green), anti-CD31 antibody (red) to reveal vasculature, and with Hoescht 3323 (blue) (magnification 200×), while flow cytomrety of dissociated UCI-101 cells from the same tumors stained with antibodies specific for MICA or MICB reveals that both ligands are upregulated (right panels; red is no TSA; blue is with TSA). (B) TSA treatment also increases the numbers of CIK cells within tumors. Athymic nu-/nu- mice implanted with UCI-101 cells as before and treated with TSA (IP, day 0) and CIK cells IV, day 1), were sacrificed on day 4 and tumors dissociated. Numbers of CIK cells in the tumor were determined after staining with an anti-human CD-56 antibody. (C) Anti-tumor effects are enhanced when CIK cells and TSA are combined. Athymic nu-/nu- mice implanted with UCI-101 tumors as before were treated with PBS, TSA (IP, day 0), CIK cells (day 1, IV) or both. The combined effect is significantly greater than any therapy used as a single agent (p=0.046)(n=8 per group). (D) Combining TSA with CIK cells pre-infected with the oncolytic vaccinia virus vvB18R (in the same tumor model) also leads to significantly enhanced anti-tumor effects relative to the same therapy without TSA (p=0.014). In this case 8 out of 10 mice had complete responses (n=10 per group).