Effects of medicated serum prepared with Chinese herbal medicine Changweiqing on pharmacokinetics of oxaliplatin in colon cancer cells

Abstract

To investigate the effects of Changweiqing-medicated serum, which was prepared with a compound traditional Chinese herbal medicine, on the reversal of oxaliplatin (L-OHP) resistance and the relationship between the reversal and cellular accumulation of platinum and proteins associated with copper transporter in HCT116/L-OHP cells. For clarifying the reversal effect of Changweiqing, methyl thiazolyl tetrazolium was applied to determine the L-OHP resistance of HCT116/L-OHP cell line. The relationship between the cellular accumulation of platinum and the L-OHP resistance in HCT116/L-OHP cells, and the effects of drug-medicated serum on intracellular contents of platinum were detected by atomic absorption spectrophotometry. Western blot method was used to determine the expressions of human copper transporter 1 (hCTR1), ATPase Cu(2+) transporting alpha polypeptide (ATP7A), copper-transporting P-type adenosine triphosphatase (ATP7B), glutathione S-transferase-π (GST-π) and multidrug resistance-associated protein 2 (MRP2). The inhibitory concentration 50% values of different pairs of L-OHP-sensitive and -resistant cells were 7.2 and 89.00. The resistance index of HCT116/L-OHP cells was 12.36. The reverse index of drug serum on HCT116/L-OHP cells was 2.74. The platinum content in HCT116/L-OHP cells was decreased compared with HCT116 cells in condition of 7.2 μg/mL L-OHP. After treating by 7.5% Changweiqing-medicated serum, the intracellular platinum contents in L-OHP-sensitive and -resistant cells were increased. It was dose-dependent that drug-medicated serum promoted the uptake of L-OHP by HCT116 or HCT116/L-OHP cells and inhibited the discharge. The 7.5% Changweiqing-medicated serum increased the expression of hCTR1 and decreased the expressions of ATP7A and ATP7B in HCT116/L-OHP cells, but had no effects on GST-π and MRP2 protein expressions. Changweiqing can reverse the L-OHP resistance of HCT116/L-OHP by increasing the cellular platinum-DNA accumulation. Down-regulation of expression of ATP7B and ATP7A, and up-regulation of hCTR1 may cause the increase of intracellular platinum content in HCT116/L-OHP cells.