Hydroxamic Acids Containing a Bicyclic Pinane Backbone as Epigenetic and Metabolic Regulators: Synergizing Agents to Overcome Cisplatin Resistance.

Multidrug resistance is the dominant obstacle to effective chemotherapy for malignant neoplasms. It is well known that neoplastic cells use a wide range of adaptive mechanisms to form and maintain resistance against antitumor agents, which makes it urgent to identify promising therapies to solve this problem. Hydroxamic acids are biologically active compounds and in recent years have been actively considered to be potentially promising drugs of various pharmacological applications. In this paper, we synthesized a number of hydroxamic acids containing a p-substituted cinnamic acid core and bearing bicyclic pinane fragments, including derivatives of (-)-myrtenol, (+)-myrtenol and (-)-nopol, as a Cap-group. Among the synthesized compounds, the most promising hydroxamic acid was identified, containing a fragment of (-)-nopol in the Cap group . This compound synergizes with cisplatin to increase its anticancer effect and overcomes cisplatin resistance, which may be associated with the inhibition of histone deacetylase 1 and glycolytic function. Taken together, our results demonstrate that the use of hydroxamic acids with a bicyclic pinane backbone can be considered to be an effective approach to the eradication of tumor cells and overcoming drug resistance in the treatment of malignant neoplasms.