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.