Effects of morphine and fentanyl on 5-fluorouracil sensitivity in human colon cancer HCT116 cells

Opioids are widely used for perioperative pain management in cancer surgery patients. It has been reported that opioids may alter cancer recurrence or progression; however, there are no published reports regarding the effects of opioids on chemotherapy after cancer surgery. Here we investigated the effects of opioids (morphine or fentanyl) on cell proliferation and 5-fluorouracil sensitivity in the human colon cancer cell line, HCT116. First, we exposed cancer cells to the opioid at various concentrations for 6 or 24 h and evaluated cell proliferation using a MTT assay. Next, to simulate the potential postoperative situation in which anticancer drugs are administered after cancer surgery, cancer cells were incubated with the opioid for 6 or 24 h, followed by treatment with 5-fluorouracil for 48 h. Although fentanyl did not affect cell proliferation, morphine exposure for 6 h enhanced the proliferation. However, sensitivity of HCT116 cells to 5-fluorouracil was not altered in all treatment groups. The current study demonstrated that the opioids commonly used during postoperative periods do not affect 5-fluorouracil sensitivity in human colon cancer HCT116 cells.