Effect of combination treatment of protocatechuic acid with 5-fluorouracil and oxaliplatin on colon cancer Caco-2 cell line

Among the most common antitumor drugs used in the treatment of colon cancer are 5-fluorouracil and oxaliplatin (5-FU and OXA). However, both these drugs have many side effects, and hence there is a need for new treatment\approach to reduce the side effects aas well as drug concentration. In this context, here, we investigated the effect of addition of protocatechuic acid (PCA) onto either monotherapies or combination therapies of 5-FU and OXA on the human colon cancer (Caco-2) cell line. In addition, we did evaluate the synergistic effect of PCA with 5-FU and OXA. Further, we determined the suppressive effects of different doses of PCA alone or in combination with 5-FU/OXA on cell proliferation after 24 and 48 hours. We identified a suppressive effect of PCA on cell viability at 48 h starting from the dose of 50 mu M Matrix metalloproteinase-2 (MMP-2) and MMP-9 gene expression levels and apoptotic effects showed significant increases and decreases depending on the dose and time applied in the experimental groups. The highest synergistic activity was seen at 2:1 concentration of 5-FU+ PCA. Our findings indicate the presence of the cytotoxic and apoptotic effects of PCA in Caco-2 cells at 48 h, increasing with a dose-and time-dependent manner.