Increased labelling of polyphosphoinositide in chemically transformed cell line C3H10T1/2 CL8.

The effect of malignant transformation of cells on phosphatidylinositol metabolism was investigated using C3H10T1/2 cells and its chemically transformed cell line, MCA CL-16 cells. We found that incorporation of [32P]Pi into polyphosphoinositide was greatly increased in the transformed cells. A similar tendency was observed when myo-[2-3H]inositol was used as a labelling reagent. It is also observed that influx of labelled inorganic phosphate is enhanced 2-fold by the cell transformation. Therefore, promotion of polyphosphoinositide labelling in the transformed cell might be caused not only by the enhanced metabolism of phosphatidylinositol but also by the increased membrane permeability for radioactive labelling reagents.