The synthesis of target compound

The synthesis of target compound (RS)-C02 is illustrated as Scheme 2. Compound (RS)-3 was synthesized as reported procedures [40] and then reacted with ethyl piperidine-4-carboxylate to yield (RS)-C01, which subsequently was converted to target molecule (RS)-C02 by performing a nucleophilic substitution reaction. Similarly, (R)-epichlorohydrin and (S)-epichlorohydrin separately reacted with compound 2 to give (R)-3 and (S)-3 [40], respectively, which were finally converted to (R)-C02 (C02R) and (S)-C02 (C02S) under the same conditions (supporting data, Scheme S1 and S2).
Results and discussion
Conclusion Epigenetic therapy has been supposed to simultaneously modify various cancer hallmarks and modulate multiple aberrant signaling pathways. However, most reported researches on epigenetic drug discovery only focused on certain hallmarks or specific pathways. In this study, we designed and synthesized a novel dual DNMT and HDAC inhibitor C02S and thoroughly evaluated its biological effect on manifold cancer hallmarks (e.g., proliferation, antiangiogenesis, invasion and migration). Results warranted C02S as a versatile antitumor agent displaying multiple antitumor biological effects. Specifically, C02S potently inhibited DNMT1, DNMT3A, DNMT3B and HDAC1 with IC50 values of 2.05, 0.93, 1.32, and 4.16 µM, respectively. Moreover, C02S exhibited remarkable inhibitory potency against DNMT and HDAC at cellular levels, inducing DNMT1 degradation and histones hyperacetylation, thereby leading to demethylation of promoter regions of TSG p16 and upregulation of tumor suppression proteins p16, p21 and TIMP3. Additionally, C02S induced DNA damages, caused G0/G1 Cordycepin arrest, and prompted apoptosis in human breast cancer cells MCF-7. Besides, C02S showed remarkable antiangiogenesis ability, inhibited migration and invasion of aggressive breast cancer cells MDA-MB-231. What’s more, C02S significantly inhibited proliferation of tumor cells MCF-7 and A549, and suppressed tumor growth in mice breast cancer models. Taken together, C02S induced multiple antitumor effects and affected various cancer hallmarks by inhibiting DNMT and HDAC simultaneously. Our results suggest that developing agents targeting DNMT and HDAC concurrently can be a practical strategy for cancer epigenetic therapy and compound C02S represents a promising lead compound for further development.
Experimental section
Introduction The benefits of bioactive compounds or plant extracts in the prevention or treatment of various diseases or symptoms have been well established (Ganesan, 2008). Previous analyses using data obtained from databases on large populations provided sufficient evidence supporting the use of plant extracts or related products (Harvey, 2008). However, the biological mechanisms underlying the beneficial effects of these natural products remain to be fully elucidated, with the goal of developing effective natural product-based drugs. Drug discovery using natural products, including the repurposing of nutraceuticals, has received research attention because of the low toxicity and disease preventive effects of natural products. However, the range of applications is primarily limited to the studies reported in literature. Recently, transcriptome analysis has been increasingly employed to investigate gene networks and elucidate the mechanisms of action of proteins or genes. In particular, analysis of gene expression profiles has led to the development of predictive workflows for diseases and natural products and has been effectively used to identify molecular targets of natural products and the associated diseases. Connectivity map (CMAP) is the gene expression profile database established from Broad Institute in 2006. CMAP is a large-scale platform that contains information on compounds and their induced changes in gene expression (Lamb et al., 2006, Smalley et al., 2010). CMAP not only provides information on the targets of compounds, but also off-target effects and mechanisms of action of unknown compounds. CMAP can be used to predict associations between gene expression profiles and novel chemicals or drugs (Smalley et al., 2010). Recently the expanded version of CMAP analysis profiles has been released and proved that it is an effective approach to identify new mechanisms of action of certain compounds (Subramanian et al., 2017).