Hydroxyethyl starch 200/0.5 decreases circulating tumor cells of colorectal cancer patients and reduces metastatic potential of colon cancer cell line through inhibiting platelets activation

Platelets play an important role in metastasis of circulating tumor cells (CTCs). It has been demonstrated that hydroxyethyl starch (HES) inhibits platelets function. However, the effect of HES on CTCs in patients with colorectal cancer remains unclear. We compared the effects of HES 200/0.5 and HES 130/0.4 on CTCs and platelets activation of colorectal patients in this study. Additionally, the effects of HES 200/0.5 or HES 130/0.4 on metastasis ability of colon cancer cell line that stimulated by activated platelets have been explored. In vivo, 90 patients undergoing colorectal cancer radical surgery received randomly 15 mL/kg of HES 200/0.5 (n = 45) or HES 130/0.4 (n = 45) infusion before surgery. Platelet glycoprotein IIb/IIIa (GPIIb/IIIa), CD62P and platelets aggregation rate (PAR) were evaluated pre-, intra- and postoperatively. Cytokeratin-20 (CK-20) mRNA was detected by reverse transcriptase polymerase chain reaction before and after surgery. In vitro, colon cancer SW480 cells were incubated with activated platelets in the presence or absence HES 200/0.5 or HES 130/0.4. The metastasis ability of SW480 cells was assessed by Transwell assay. The results showed that CK-20 mRNA positive rate in HES 200/0.5 group after surgery was decreased significantly as compared to group HES 130/0.4 (χ ² = 6.164, P = 0.013). Simultaneously, a more pronounced inhibition of platelets activation was observed in group HES 200/0.5. A positive correlation between platelets activation marker and CK-20 mRNA positive rate was found. In vitro, HES 200/0.5, but not HES 130/0.4, decreased the invasion and migration ability of SW480 cells that induced by activated platelets. Besides, the expression of GPIIb/IIIa, CD62P and PAR was inhibited more strongly in group HES 200/0.5 than those in group HES 130/0.4. In summary, we found that HES 200/0.5 significantly decreased CTCs of patients undergoing colorectal cancer radical surgery as compared to HES 130/0.4, which might be associated with inhibiting platelets activation of HES 200/0.5. Furthermore, HES 200/0.5, but not HES 130/0.4, reduced the metastatic potential of colon cell line stimulated by activated platelets through depressing platelets activation. Modulation of platelets activity may be a novel strategy to minimize the risk of metastasis during surgery.