Biomimetic synthesis of the natural product salviadione and its hybrids: discovery of tissue-specific anti-inflammatory agents for acute lung injury.

Acute lung injury (ALI) is an inflammatory disease with no effective pharmacological treatment. The therapeutic potential of the anti-inflammatory natural product tanshinone IIA (2) for ALI is seriously impaired by its poor pharmacokinetic (PK) properties. Inspired by the unique benzo[def]carbazole-3,5-dione (BCD) core of the natural product salviadione (5), a series of furan-fused BCD hybrids of 5 with 2 was rationally designed with the aim to improve both PK properties and the anti-inflammatory activity. A biomimetic synthetic approach featuring one-pot tandem N-heterocyclization was first developed for convenient assembly of salviadione (56% overall yield over 2 steps) and the designed hybrids (35-85% yields in one step). Compared to 2, most of the resulting compounds exhibited a markedly enhanced inhibitory effect against LPS-induced release of pro-inflammatory cytokines in macrophages. Particularly, compound 15a not only possessed the most potent activity in vitro, but also exhibited significantly improved metabolic stability (4- to 7-fold enhancement), pharmacokinetic properties (T 1/2 = 4.05 h; F = 30.2%), and preferable lung tissue distribution (11- to 300-fold selectivity). An in vivo study in mice showed that pretreatment with 15a at 5 mg kg-1 distinctly attenuated LPS-induced ALI via lung tissue-specific anti-inflammatory actions, indicating that the furan-fused BCD core presents a unique chemotype with promising therapeutic potential for ALI.

Structural Modification of Natural Product Tanshinone I Leading to Discovery of Novel Nitrogen-Enriched Derivatives with Enhanced Anticancer Profile and Improved Drug-like Properties.

The clinical development of natural product tanshinone I (1) for cancer therapy is hampered by its weak potency and poor drug-like properties. Herein, a more broad and systemic structural modification on 1 was conducted to generate four series of new tanshinone derivatives. Among them, the lactam derivative 22h demonstrated the most potent antiproliferative activity against KB and drug-resistant KB/VCR cancer cells, which are approximately 13- to 49-fold more potent than 1. Compound 22h possesses significantly improved drug-like properties including aqueous solubility (15.7 mg/mL), metabolic stability of liver microsomes, and PK characters (T1/2 = 2.58 h; F = 21%) when compared to 1. Preliminary mechanism studies showed that 22h significantly induced apoptosis of HCT116 cells, at least partially, through activation of caspase-3/-7. More importantly, administration of 22h at 10 mg/kg significantly suppressed the tumor growth of HCT116 xenograft in vivo without significant loss of body weight of the tested nude mice.

Catalyst-Free sp3 C-H Acyloxylation: Regioselective Synthesis of 1-Acyloxy Derivatives of the Natural Product Tanshinone IIA.

Tanshinone IIA is a valuable bioactive natural product isolated from the well-known Chinese herb Danshen. Structural manipulation of the A-ring of tanshinone IIA is rather limited. In this study, a substrate tautomerization-induced catalyst-free benzylic sp3 C-H acyloxylation approach is reported that allows the direct introduction of various acyloxy groups at the A-ring benzylic methylene of various tanshinone IIA substrates, thus avoiding the use of expensive transition metal catalysts and the production of harmful byproducts. This approach features a unique acid-induced reversible enolization/oxa-conjugate addition process followed by oxidation to exclusively give a series of diverse 1-acyloxylated derivatives under simple conditions in a regioselective manner. Compared with the literature procedures, this protocol demonstrates a higher efficiency, a more robust functional-group tolerance, atom economy, and lower cost.

Computational drug repositioning for cancer therapeutics.

Due to ever-increasing failure rates, high cost, unsatisfactory safety profile, and limited efficacy associated with anticancer drug development, the repositioning of established non-cancer drugs for new oncology indications has emerged as an increasingly attractive approach to addressing the unmet cancer-related medical need. With the rapid development of bioinformatics, chemoinformatics as well as high-performance computing, drug repositioning is becoming more intentional than ever, and a significant surge of computational approaches has been well established to greatly facilitate drug repositioning for cancer treatment. In this review, we provide a brief overview of recent advances in the computational drug repositioning for anticancer applications with a specific emphasis on repositioning of non-cancer drugs by use of various computational approaches.

Targeting PI3Kδ: emerging therapy for chronic lymphocytic leukemia and beyond.

Chronic lymphocytic leukemia (CLL) remains the most incurable leukemia. Early chemotherapeutic treatments, including alkylating agents, purine nucleoside derivatives, and immunotherapeutic antibodies, only show limited benefits for patients but severe off-target related side effects. Recent advances in understanding of the critical molecular pathways of regulating proliferation and survival of B-CLL cells have spurred a new therapeutical strategy by selectively targeting phosphoinositide 3-kinase delta (PI3Kδ). Idelalisib, a first-in-class PI3Kδ-selective small molecule has received the FDA's fast-track approval in July of 2014 as a new treatment of CLL, indolent B-cell non-Hodgkin's lymphoma, and relapsed small lymphocytic lymphoma. Undoubtedly, the success of idelalisib has provided a solid support in the development of PI3Kδ-specific inhibitors and reformed the concept of treating CLL. However, the number of reported selective inhibitors of PI3Kδ is very limited and very few have advanced into clinical trials. The mechanism of their actions remains elusive. More profound understanding on the modes of action of new PI3Kδ inhibitors will further validate the PI3Kδ-targeting strategy, and help to identify biomarkers capable of stratifying patients who will most likely benefit from the therapy.