Antimetastatic effect of nanodiamond-conjugated quercetin against colon cancer: an in vivo study

Background/aim: Quercetin (Q) is a compound that can inhibit the growth of cancer cells in the colon; however, to do so, a high dose is needed, requiring a drug delivery system to target cancer endothelial cells directly. This study investigates the potency of nanodiamond conjugated quercetin (NDQ) as an anticancer drug against colon cancer in Rattus norvegicus induced by N-methyl N-Nitrosourea (MNU). Materials and methods: This study is experimental-based and was designed using a six-group treatment method, namely normal control (KN: not treated by MNU, nanodiamond (ND), or Q); negative control (K–: treated by MNU); positive control (K+: treated by MNU and capecitabine); ND (treated by MNU and NDs); Q (treated by MNU and Q); and NDQ (treated by MNU and NDQ). To induce colon cancer in rats, MNU (10 mg/Kg BW) was administrated intrarectally three times per week for four weeks. The treatment of Q (40 mg/Kg BW) or NDQ (40 mg/Kg BW) was given intraperitoneally twice a week for 6 weeks. Cancer progression of all cohorts was evaluated by performing body and colon weight measurements, which involved the following: ELISA assay-specific to metastatic marker matrix metalloprotein-9 (MMP-9), carcinoembryonic antigen (CEA), hypoxia-inducible factor 1 α (HIF1α), vascular endothelial growth factor, protein 53 (p53) and immunohistochemistry staining of Caspase-3 and Ki-67 proteins. Observation of cancer metastasis to the lung was also performed. Results: NDQ significantly inhibited cancer aggressiveness by causing an increment in body weight gain and the growth rate—while reducing the colon weight compared to the K– group. Moreover, decreased levels of MMP-9, CEA, HIF-1α, and Ki67 and increased levels of p53 and Caspase-3 were more significant in the NDQ group than in the Q group. The lung tumor metastases in the NDQ group were fewer than in the K– group. Conclusion: NDQ increased Q’s anticancer activity, suggesting that NDs have an effective drug delivery property.