Dehydroberberine Analogue Nanoassemblies for Inducing and Self-Reporting Mitochondrial Dysfunction in Tumor Cells.

Mitochondria-targeting probes that allow us to induce and report mitochondrial dysfunction have become promising theranostic agents for cancer; however, the lack of selectivity toward tumor cells over normal tissue cells has impeded the treatment outcome. Herein, we develop 10 fluorescent dehydroberberine derivatives (B1-B10) capable of lighting up mitochondria and exerting moderate cytotoxicity against tumor cells. To enable the selectivity toward tumor cells over normal tissue cells, we introduced a lipophilic anion tetraphenylborate (TPB-) into the most potent compound B3+Cl- to drive molecular self-assembly into monodisperse organic nanoassemblies (B3NPs) in aqueous solution, which efficiently enhance the delivery of B3+ into HeLa cells assisted by an electrostatic interaction-driven anion-exchange process. Fluorescence imaging reveals that B3+ can initially accumulate in the mitochondria after entering HeLa cells, followed by inducing mitochondrial dysfunction and then migrating into the nucleus. Strong B3+ fluorescence translocating from mitochondria to nucleus can be monitored in real-time, allowing for self-reporting of mitochondrial dysfunction in HeLa cells. Moreover, we demonstrate that B3NPs exert significantly higher cytotoxicity against seven different tumor cells (e.g., U87MG, HeLa, MDA-MB-468, MDA-MB-435, MDA-MB-231, MCF-7, and HCT116 cells) compared to human normal tissue cells (e.g., HUVEC, HEK293). This work highlights the utility of the self-assembly approach to improve the cytotoxicity and selectivity of mitochondria-targeting agents against tumor cells.

Design, synthesis, and biological evaluation of tetrahydroisoquinolines derivatives as novel, selective PDE4 inhibitors for antipsoriasis treatment.

Psoriasis is a kind of chronic inflammatory skin disorder, while the long-term use of conventional therapies for this disease are limited by severe adverse effects. Novel small molecules associated with new therapeutic mechanisms are greatly needed. It is known that phosphodiesterase 4 (PDE4) plays a central role in regulating inflammatory responses through hydrolyzing intracellular cyclic adenosine monophosphate (cAMP), making PDE4 to be an important target for the treatment of inflammatory diseases (e.g. psoriasis). In our previous work, we identified a series of novel PDE4 inhibitors with a tetrahydroisoquinoline scaffold through structure-based drug design, among which compound 1 showed moderate inhibition activity against PDE4. In this study, a series of novel tetrahydroisoquinoline derivatives were developed based on the crystal structure of PDE4D in complex with compound 1. Anti-inflammatory effects of these compounds were evaluated, and compound 36, with high safety, permeability and selectivity, exhibited significant inhibitory potency against the enzymatic activity of PDE4D and the TNF-α release from the LPS-stimulated RAW 264.7 and hPBMCs. Moreover, an in vivo study demonstrated that a topical administration of 36 achieved more significant efficacy than calcipotriol to improve the features of psoriasis-like skin inflammation. Overall, our study provides a basis for further development of tetrahydroisoquinoline-based PDE4 inhibitors against psoriasis.

Structure-Aided Identification and Optimization of Tetrahydro-isoquinolines as Novel PDE4 Inhibitors Leading to Discovery of an Effective Antipsoriasis Agent.

Psoriasis is a common, chronic inflammatory disease characterized by abnormal skin plaques, and the effectiveness of phosphodiesterase 4 (PDE4) inhibitor to lessen the symptoms of psoriasis has been proved. Aiming to find a novel PDE4 inhibitor acting as an effective, safe, and convenient therapeutic agent, we constructed a library consisting of berberine analogues, and compound 2 with a tetrahydroisoquinoline scaffold was identified as a novel and potent hit. The structure-aided and cell-based structure-activity relationship studies on a series of tetrahydro-isoquinolines lead to efficient discovery of a qualified lead compound (16) with the high potency and selectivity, well-characterized binding mechanism, high cell permeability, good safety and pharmacokinetic profile, and impressive in vivo efficacy on antipsoriasis, in particular with a topical application. Thus, our study presents a prime example for efficient discovery of novel, potent lead compounds derived from natural products using a combination of medicinal chemistry, biochemical, biophysical, and pharmacological approaches.

Self-assembly of Fluorescent Dehydroberberine Enhances Mitochondria-Dependent Antitumor Efficacy.

Selective imaging and inducing mitochondrial dysfunction in tumor cells using mitochondria-targeting probes has become as a promising approach for cancer diagnosis and therapy. Here, we report the design of a fluorescent berberine analog, dehydroberberine (DH-BBR), as a new mitochondria-targeting probe capable of self-assembling into monodisperse organic nanoparticles (DTNPs) upon integration with a lipophilic counter anion, allowing for enhanced fluorescence imaging and treatment of tumors in living mice. X-ray crystallography revealed that the self-assembly process was attributed to a synergy of different molecular interactions, including π-π stacking, O⋅⋅⋅π interaction and electrostatic interaction between DH-BBR and counter anions. We demonstrated that DTNPs could efficiently enter tumor tissue following intravenous injection and enhance mitochondrial delivery of DH-BBR via an electrostatic interaction driven anion exchange process. Selective accumulation in the mitochondria capable of emitting strong fluorescence and causing mitochondrial dysfunction was achieved, enabling efficient inhibition of tumor growth in living mice. This study demonstrates promise for applying lipophilic anions to control molecular self-assembly and tune antitumor activity of mitochondria-targeting probes, which can facilitate to improve cancer treatment in vivo.

Design, synthesis, and structure-activity relationships of novel 4,7,12,12a-tetrahydro-5H-thieno[3',2':3,4]pyrido[1,2-b]isoquinoline and 5,8,12,12a-tetrahydro-6H-thieno[2',3':4,5]pyrido[2,1-a]isoquinoline derivatives as cellular activators of adenosine 5'-monophosphate-activated protein kinase (AMPK).

To discover more derivatives with better glucose-lowering efficacy compared with berberine, twenty-three novel compounds with 4,7,12,12a-tetrahydro-5H-thieno[3',2':3,4]pyrido[1,2-b]isoquinoline or 5,8,12,12a-tetrahydro-6H-thieno[2',3':4,5]pyrido[2,1-a]isoquinoline cores were designed, synthesized, and biologically evaluated in vitro in continuation of our previous work on indirect activators of adenosine 5'-monophosphate-activated protein kinase (AMPK). Nine compounds effectively stimulated glucose consumption (>2.3-fold at 10 µM) in L6 myotube cells, and two compounds (4d and 4s) exhibited superior inhibitory activity (<57.6% at 5 µM) compared with berberine on gluconeogenesis in rat primary hepatocytes. Additionally, these compounds significantly up-regulated the phosphorylation of AMPK and its substrate, acetyl-CoA carboxylase (ACC) and slightly decreased the mitochondrial membrane potential in L6 myotube cells.

Design, synthesis and biological evaluation of 4,7,12,12a-tetrahydro-5H-thieno[3',2':3,4]pyrido[1,2-b]isoquinolines as novel adenosine 5'-monophosphate-activated protein kinase (AMPK) indirect activators for the treatment of type 2 diabetes.

A series of novel berberine derivatives, 4,7,12,12a-tetrahydro-5H-thieno[3',2':3,4]pyrido[1,2-b]isoquinolines was designed, synthesized, and biologically evaluated for their anti-diabetic activity. Following the evaluation in two types of cells, compounds 4aa, 4bq, and 4bv stimulated glucose consumption (1.8- to 2.3-fold), reduced gluconeogenesis (60-85%), inhibited mitochondria respiratory chain complex I and activated AMPK indirectly. In a db/db mice model, compounds 4bq and 4bv lowered fasting blood glucose at a dose of 120 mg/kg/day. In addition, compounds 4bq and 4bv were found to possess improved pharmacokinetic profiles (bioavailability 45 and 106%, respectively) compared to berberine. Compounds 4bq and 4bv exhibited no obvious hERG inhibition (IC50 > 10 µM).

Fluorescent Coumarin-Artemisinin Conjugates as Mitochondria-Targeting Theranostic Probes for Enhanced Anticancer Activities.

Mitochondria-targeting theranostic probes that enable the simultaneously reporting of and triggering of mitochondrial dysfunctions in cancer cells are highly attractive for cancer diagnosis and therapy. Three fluorescent mitochondria-targeting theranostic probes have been developed by linking a mitochondrial dye, coumarin-3-carboximide, with a widely used traditional Chinese medicine, artemisinin, to kill cancer cells. Fluorescence images showed that the designed coumarin-artemisinin conjugates localized mainly in mitochondria, leading to enhanced anticancer activities over artemisinin. High cytotoxicity against cancer cells correlated with the strong ability to accumulate in mitochondria, which could efficiently increase the intracellular reactive oxygen species level and induce cell apoptosis. This study highlights the potential of using mitochondria-targeting fluorophores to selectively trigger and directly visualize subcellular drug delivery in living cells.