Tumor inhibition by titanocene complexes. Activity against B16 melanoma and colon 38 carcinoma

In the present study, the antitumor activity of some titanocene derivatives (C5H5)2TiX2 (I, X = Cl; II, X = Br; III, X = cis-OOCCH = CHCOOH; IV, X = p-SC6H4NH3+Cl-) was investigated against B16 melanoma and colon 38 carcinoma. Both tumors grew subcutaneously as solid tumors in mice. Substances were applied intraperitoneally either as single, triple or 5-fold injections. Against both tumors, satisfactory results were observed for the chloro, bromo and aminothiophenolato derivatives I, II and IV, resp. They reduced tumor growth by 60-80% to 40-20% of control values. These effects underline the antitumor potency of titanocene complexes and show that titanocene dihalides as well as titanocene derivatives containing hydrophilic ligands X are able to inhibit the growth of various solid experimental tumors.