Table 1.

Inhibition of tumor formation by down-regulation of Sp1 expression in malignant cell lines

Cell linesRelative Sp1 level *Frequency (tumors/sites)Latency (wk)
PH2MT1.06/64
V10.94/44-6
V21.26/64-6
SpR40.74/65-8
SpR30.64/48-10
SpR50.46/1612-31
SpR 10.20/6 NA §
SpR 20.20/6 NA §
γ2-A/SB11.06/65-6
V11.05/64-5
V21.06/64-5
SpR10.10/6 NA §
SpR20.10/6 NA §
SpR30.10/6 NA §
  • NOTE: Cells (106) were injected s.c. into the right and left rear flank regions of athymic mice (two sites per mouse). Mice were examined weekly for tumors. When tumors reached ∼1 cm in diameter, they were removed. V, vector control; SpR, transfectants expressing Sp1 U1snRNA/Ribozyme.

  • * Relative Sp1 level determined by Western blotting.

  • Time required for tumors to reach ∼1 cm.

  • No tumors formed within the 26 to 30-week observation period.

  • § Not applicable.