The platinum drugs belong to prevailing chemotherapeutics used in the treatment of cancer. At present, however, the search for new anticancer metal-based drugs that operate by the mechanisms distinct from those of the conventional chemotherapeutics is very active. Furthermore, it has been demonstrated that cytotoxic chemotherapy and immunotherapy may exert a highly synergistic anticancer activity. Thus, the development of antitumor platinum and other metal-based drugs that exhibit cytostatic effects and concurrently elicit immunogenic cell death (ICD) has shown promise for cancer treatment. Notably, conventional platinum drug oxaliplatin ([Pt(1R,2R-DACH)(oxalate)], DACH = diaminocyclohexane) is a well-known agent that displays both cytostatic and immune responses. Moreover, it was also demonstrated that even minor derivatization of the unleaving cycloalkyl moiety in oxaliplatin might have a pronounced effect on its immunomodulatory activity. Here, we investigated how replacing the 1R,2R- diaminocyclohexane ring by 1,3-diaminocycloalkane (alkane = butane, pentane, or hexane) affects the ability to evoke secretion of damage-associated molecular patterns characteristic of ICD in model murine colorectal carcinoma cell line CT26. The results indicate that among the investigated [Pt(cis-1,3-diaminocycloalkane)Cl2] complexes, the complex containing the cyclobutyl moiety exhibits the hallmarks typical of ICD inducers. Thus, [Pt(cis-1,3-diaminocyclobutane)Cl2] may expand the spectrum of anticancer chemotherapeutics capable of inducing ICD in cancer cells and might be of interest for further (pre)clinical development.
Keywords: CT26 cell line; Cancer; Damage-associated molecular pattern; Immunogenic cell death; Platinum.
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