Role and mechanism of organic cation transporter 3 in oxaliplatin treatment of colon cancer in vitro and in vivo

Oxaliplatin (OXA) is routinely used as the first-line treatment for colorectal cancer (CRC). The addition of OXA to chemotherapy has significantly improved the prognosis of patients with CRC; however, some cases are resistant to OXA. The present study explored the influence of organic cation transporter 3 (OCT3) expression on the effects of OXA on CRC cell viability, and investigated the direct effects of OCT3 on viability, invasion and migration of CRC cells using MTT assay, wound healing assay, reverse transcription-quantitative polymerase chain reaction, inductively coupled plasma mass spectrometry and lentiviral interference. The results demonstrated that OXA cellular concentration and OXA-induced cytotoxicity were significantly increased in response to high expression of OCT3, whereas OCT3 knockdown directly increased the invasion and migration of colon cancer cells. Furthermore, upregulation of OCT3 expression in colon cancer xenografts via treatment with the DNA methyltransferase inhibitor decitabine increased cellular OXA concentration and improved the curative effect of OXA. These results collectively indicated that OCT3 may enhance the effects of OXA in CRC cells and may directly inhibit their invasion and migration. Therefore, OCT3 may be a therapeutic target in patients with CRC.