Specifically capturing and restraining residual circulating tumor cells (CTCs) in cancer patients are the sine qua non for safely and effectively preventing cancer metastasis, to which the current chemotherapy has been limited due to its toxicity. Moreover, because of CTCs’ rarity and low activity, the current technology for capturing CTCs based solely on a single surface biomarker has limited capacity and is used mainly for in vitro diagnosis. Here, it is possible to sequentially conjugate two CTCs antibodies (aEpCAM and aSlex) to the functionalized dendrimers to specifically capture human hepatocellular CTCs in both artificial and clinical patient blood samples, and restrain their activities. The molecular entities of the conjugates are demonstrated by various means. The dual antibody conjugate captured CTCs threefold more than the single counterparts from the high concentrations of interfering red blood cells or leukocytes, as well as from the blood of liver cancer patients, and exhibits the superiority to their single counterparts in down-regulating the captured CTCs. These results collectively provide the strong evidence that two antibodies can be compatibly conjugated to a nanomaterial, resulting in an enhanced specificity in restraining CTCs in blood.

Seventeen novel emodin derivatives were synthesized, and the structures were confirmed by IR, H NMR, MS, and elemental analysis. The cytotoxic activity of the derivatives was evaluated against A375, BGC-823, HepG2, and HELF cells by MTT assay. Compound 9a with highest potency and low toxicity was selected to further investigate its detailed molecular mechanism. The lead compound 9a induced a loss of the mitochondrial transmembrane potential (▵Ψm), an increase in reactive oxygen species (ROS), release of cytochrome c and activation of caspase-3 and caspase-9. In addition, the confocal study showed that emodin derivative 9a (containing asymmetric hydrocarbon tails) was mainly localized in mitochondria, demonstrating a key role of the mitochondria-mediated apoptosis pathway in cancer cells. Taken together, the results demonstrate that embodin derivative 9a preferentially regulates the ROS-mediated apoptosis in A375 cells through the induction of cytochrome c expression and activation of caspase-3 and caspase-9 proteins.

Ursolic acid (UA) is a natural product which has been shown to possess a wide range of pharmacological activities, in particular those with anticancer activity. In this study, 13 novel ursolic acid derivatives were designed and synthesized in an attempt to further improve compound potency. The structures of the newly synthesized compounds were confirmed using mass spectrometry, infrared spectroscopy, and ¹H NMR. The ability of the UA derivatives to inhibit cell growth was assayed against both various tumor cell lines and a non-pathogenic cell line, HELF. Analysis of theoretical toxicity risks for all derivatives was performed using OSIRIS and indicated that the majority of compounds would present moderate to low risks. Pharmacological results indicated that the majority of the derivatives were more potent growth inhibitors than UA. In particular, 5b demonstrated IC₅₀ values ranging from 4.09 ± 0.27 to 7.78 ± 0.43 μm against 12 different tumor cell lines. Flow cytometry analysis indicated that 5b induced G0/G1 arrest in three of these cell lines. These results were validated by structural docking studies, which confirmed that UA could bind to cyclins D1 (Cyc D1) and cyclin-dependent kinases (CDK6), the key regulators of G0/G1 transition in cell cycle, while the piperazine moiety of 5b could bind with glucokinase (GK), glucose transporter 1 (GLUT1), and ATPase, which are the main proteins involved in cancer cell metabolism. Acridine orange/ethidium bromide staining confirmed that 5b was capable of inducing apoptosis and decreasing cell viability in a dose-dependent manner.