Calcium Sensitivity of Cell Cultures Derived from Adenovirus-Induced Tumors.∗

Summary Cell lines derived from adeno-virus-induced tumors or adenovirus-trans-formed cell lines clumped or retracted in 7.5 mM calcium or less, a characteristic generally not shown by cells derived from other virus-induced tumors or cells transformed by other viruses. Similarly, standard primary, diploid, and heteroploid cell cultures were not sensitive to 7.5 mM calcium. In support of these observations, the use of a low calcium medium facilitated the passaging of adenovirus-trans-formed cells in tissue culture; however, the use of a completely calcium-free medium resulted in a deficiency which caused detachment of the culture. The calcium effect may be useful as a marker to substantiate other evidence that a tumor was induced by adeno-virus or that a cell line was transformed by adenovirus.