Macrophorins H and L, two new HMG-conjugate macrophorins from rihzospheric Penicillium sp. NX-05-G-3.

Macrophorins H (4) and L (5), two rare HMG-conjugate macrophorins along with three known macrophorins (1-3), three DMOA-derived meroterpenoids (6-8) and two ergosterol derivates (9-10) were isolated from sterilized rice medium cultured Penicillium sp. NX-05-G-3. Their structures were elucidated by 1D and 2D NMR. The cytotoxicities of all compounds were evaluated, and compounds 1 and 2 showed extensive cytotoxicity against human cancer cell lines Hela, SCC15, MDA-MB-453 and A549, with IC50 values ranging from 17.6 to 32.8 µM.

Design, synthesis and biological evaluation of indazole derivatives as selective covalent inhibitors of FGFR4 in wild-type and gatekeeper mutants.

Fibroblast growth factor receptor 4 (FGFR4) has been proved to be an effective target for cancer therapy. Aberration in FGF19/FGFR4 signaling is oncogenic driving force in human hepatocellular carcinoma (HCC). FGFR4 gatekeeper mutations induced acquired resistance remains an unmet clinical challenge for HCC treatment. In this study, a series of 1H-indazole derivatives were designed and synthesized as new irreversible inhibitors of wild-type and gatekeeper mutant FGFR4. These new derivatives showed significant FGFR4 inhibitory and antitumor activities, among which compound 27i was demonstrated to be the most potent compound (FGFR4 IC50 = 2.4 nM). Remarkably, compound 27i exhibited no activity against a panel of 381 kinases at 1 µM. Additionally, compound 27i displayed nanomolar IC50s against huh7 (IC50 = 21 nM) and two mutant cell lines, BaF3/ETV6-FGFR4-V550L and BaF3/ETV6-FGFR4-N535K (IC50 = 2.5/171 nM). Meanwhile, compound 27i exhibited potent antitumor potency (TGI: 83.0%, 40 mg/kg, BID) in Huh7 xenograft mouse models with no obvious toxicity observed. Overall, compound 27i was identified as a promising preclinical candidate for overcoming FGFR4 gatekeeper mutations for HCC treatment.

Design and Synthesis of Fibroblast Growth Factor Receptor (FGFR) and Histone Deacetylase (HDAC) Dual Inhibitors for the Treatment of Cancer.

The activation of the STAT signal after incubation with the HDAC inhibitor represents a key mechanism causing resistance to HDAC inhibitors in some solid tumor cells, while the FGFR inhibitor could downregulate the level of pSTAT3. Inspired by the therapeutic prospect of FGFR/HDAC dual inhibitors, we designed and synthesized a series of quinoxalinopyrazole hydroxamate derivatives as FGFR/HDAC dual inhibitors. Among them, compound 10e potently inhibited FGFR1-4 and HDAC1/2/6/8 and presented improved antiproliferative effects of tumor cells. Further studies indicated that 10e also downregulated the expression of pSTAT3, potentially overcoming resistance to HDAC inhibitors. What's more, 10e significantly inhibited the tumor growth in HCT116 and SNU-16 xenograft models with favorable pharmacokinetic profiles. Collectively, these results supported that 10e could be a new drug candidate for malignant tumors.

A novel small molecule RK-019 inhibits FGFR2-amplification gastric cancer cell proliferation and induces apoptosis in vitro and in vivo.

Gastric cancer (GC) is one of the most malignant cancers and is estimated to be fifth in incidence ratio and the third leading cause of cancer death worldwide. Despite advances in GC treatment, poor prognosis and low survival rate necessitate the development of novel treatment options. Fibroblast growth factor receptors (FGFRs) have been suggested to be potential targets for GC treatment. In this study, we report a novel selective FGFR inhibitor, RK-019, with a pyrido [1, 2-a] pyrimidinone skeleton. In vitro, RK-019 showed excellent FGFR1-4 inhibitory activities and strong anti-proliferative effects against FGFR2-amplification (FGFR2-amp) GC cells, including SNU-16 and KATO III cells. Treatment with RK-019 suppressed phosphorylation of FGFR and its downstream pathway proteins, such as FRS2, PLCγ, AKT, and Erk, resulting in cell cycle arrest and induction of apoptosis. Furthermore, daily oral administration of RK-019 could attenuate tumor xenograft growth with no adverse effects. Here, we reported a novel specific FGFR inhibitor, RK-019, with potent anti-FGFR2-amp GC activity both in vitro and in vivo.

Design, synthesis and biological evaluation of 7-((7H-pyrrolo[2,3-d]pyrimidin-4-yl)oxy)-2,3-dihydro-1H-inden-1-one derivatives as potent FAK inhibitors for the treatment of ovarian cancer.

Focal adhesion kinase (FAK) promotes tumor progression by intracellular signal transduction and regulation of gene expression and protein turnover, which is a compelling therapeutic target for various cancer types, including ovarian cancer. However, the clinical responses of FAK inhibitors remain unsatisfactory. Here, we describe the discovery of FAK inhibitors using a scaffold hopping strategy. Structure-activity relationship (SAR) exploration identified 36 as a potent FAK inhibitor, which exhibited inhibitory activities against FAK signaling in vitro. Treatment with 36 not only decreased migration and invasion of PA-1 cells, but also reduced expression of MMP-2 and MMP-9. Moreover, 36 inhibited tumor growth and metastasis, and no obvious adverse effects were observed during the in vivo study. These results revealed the potential of FAK inhibitor 36 for treatment of ovarian cancer.

Structure-guided discovery of novel potent and efficacious proteolysis targeting chimera (PROTAC) degrader of BRD4.

Bromodomain-containing protein 4 (BRD4) has been identified as a potential target in the treatment of many cancers and several BRD4 inhibitors have entered clinical studies. Previous studies have shown that BRD4 degraders have potential to overcome resistance to BRD4 inhibitors. However, most of the BRD4 degraders have poor solubility and bioavailability, one of which the reason is large molecular weight. Here, we describe the design, synthesis, and evaluation studies of a BRD4 degrader based on the proteolysis targeting chimeras (PROTAC) concept. Our efforts have led to the discovery of compound 15, which is a weak inhibitor and potent BRD4 degrader with a molecular weight of 821.8. In vitro, 15 can completely degrade BRD4 at nanomolar concentration, with DC50 = 0.25 and 3.15 nM in MV4-11 and RS4-11 cell lines, respectively. Further optimization of compound 15 may reduce its molecular weight and improve druggabillity, and provide a new choice for the treatment of cancer.

Lead optimization to improve the antiviral potency of 2-aminobenzamide derivatives targeting HIV-1 Vif-A3G axis.

The viral infectivity factor (Vif)-apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G (APOBEC3G) axis has been recognized as a valid target for developing novel small-molecule therapies for acquired immune deficiency syndrome (AIDS) or for enhancing innate immunity against viruses. Our previous work reported the novel Vif antagonist 2-amino-N-(2-methoxyphenyl)-6-((4-nitrophenyl)sulfonyl)benzamide (2) with strong antiviral activity. In this work, through optimizations of ring C of 2, we discovered the more potent compound 6m with an EC50 of 0.07 µM in non-permissive H9 cells, reflecting an approximately 5-fold enhancement of antiviral activity compared to that of 2. Western blotting indicated that 6m more strongly suppressed the defensive protein Vif than 2 at the same concentration. Furthermore, 6m suppressed the replication of various clinical drug-resistant HIV strains (FI, NRTI, NNRTI, IN and PI) with relatively high efficacy. These results suggested that compound 6m is a more potent candidate for treating AIDS.

Design, synthesis and biological evaluations of a series of Pyrido[1,2-a]pyrimidinone derivatives as novel selective FGFR inhibitors.

Aberrant signaling of fibroblast growth factor receptors (FGFRs) has been identified as a driver of tumorigenesis and the development of many solid tumors, making FGFRs a compelling target for anticancer therapy. Herein, we describe the design and synthesis of pyrido[1,2-a]pyrimidinone derivatives as potent FGFR inhibitors. Examination of structure-activity relationships and preliminary assessment identified 23d as a novel FGFR inhibitor that displayed excellent potency in vitro. Candidate 23d suppressed the phosphorylation of FGFR signaling pathways and induced cell cycle arrest and apoptosis at low nanomolar concentration. In the kinase inhibition profile, 23d showed excellent kinase selectivity for the FGFR family. Furthermore, 23d showed higher aqueous solubility than Erdafitinib. Moreover, 23d exhibited potent antitumor activity (tumor growth inhibition = 106.4%) in FGFR2-amplified SNU-16 gastric cancer xenograft model using a daily oral dose of 30 mg/kg. These results suggest that 23d is a promising candidate for further drug development.

A novel benzothiazinethione analogue SKLB-TB1001 displays potent antimycobacterial activities in a series of murine models.

New chemotherapeutic compounds and regimens are needed to combat multidrug-resistant Mycobacterium tuberculosis. Here, we used a series of murine models to assess an antitubercular lead compound SKLB-TB1001. In the Mycobacterium bovis bacillus Calmette-Guérin and the acute M. tuberculosis H37Rv infection mouse models, SKLB-TB1001 significantly attenuated the mycobacterial load in lungs and spleens. The colony forming unit counts and histological examination of lungs from H37Rv infected mice revealed that the benzothiazinethione analogue SKLB-TB1001 as a higher dose level was as effective as isoniazid. Moreover, in a multidrug-resistant (MDR)-TB mouse model, SKLB-TB1001 showed significant activity in a dose-dependent manner and was more effective than streptomycin. These results suggested that SKLB-TB1001 could be an antitubercular drug candidate worth further investigation.

Benzothiazinethione is a potent preclinical candidate for the treatment of drug-resistant tuberculosis.

New chemotherapeutic compounds are needed to combat multidrug-resistant Mycobacterium tuberculosis (Mtb), which remains a serious public-health challenge. Decaprenylphosphoryl-ß-D-ribose 2'-epimerase (DprE1 enzyme) has been characterized as an attractive therapeutic target to address this urgent demand. Herein, we have identified a new class of DprE1 inhibitors benzothiazinethiones as antitubercular agents. Benzothiazinethione analogue SKLB-TB1001 exhibited excellent activity against Mtb in the Microplate Alamar blue assay and intracellular model, meanwhile SKLB-TB1001 was also highly potent against multi-drug resistant extensively and drug resistant clinical isolates. Importantly, no antagonism interaction was found with any two-drug combinations tested in the present study and the combination of SKLB-TB1001 with rifampicin (RMP) was proved to be synergistic. Furthermore, benzothiazinethione showed superb in vivo antitubercular efficacy in an acute Mtb infection mouse model, significantly better than that of BTZ043. These data combined with the bioavailability and safety profiles of benzothiazinethione indicates SKLB-TB1001 is a promising preclinical candidate for the treatment of drug-resistant tuberculosis.

Identification of novel 2-aminothiazole conjugated nitrofuran as antitubercular and antibacterial agents.

The emergence of antibiotic resistant pathogens is an ongoing main problem in the therapy of bacterial infections. In order to develop promising antitubercular and antibacterial lead compounds, we designed and synthesized a new series of derivatives of 2-aminothiazole conjugated nitrofuran with activities against both Mycobacterium tuberculosis and Staphylococcus aureus. Eight compounds 12e, 12k, 12l, 12m, 18a, 18d, 18e, and 18j emerged as promising antitubercular agents. Structure-activity relationships (SARs) were discussed and showed that the derivatives substituted at the position-3 of benzene of 5-nitro-N-(4-phenylthiazol-2-yl)furan-2-carboxamide exhibited superior potency. The most potent compound 18e, substituted with benzamide at this position, displayed minimum inhibitory concentrations (MICs) of 0.27µg/mL against Mtb H37Ra and 1.36µg/mL against S. aureus. Furthermore, compound 18e had no obvious cytotoxicity to normal Vero cells (IC50=50.2µM). The results suggest that the novel scaffolds of aminothiazole conjugated nitrofuran would be a promising class of potent antitubercular and antimicrobial agents.

Synthesis and antitubercular evaluation of 4-carbonyl piperazine substituted 1,3-benzothiazin-4-one derivatives.

Tuberculosis (TB) remains a major human health problem. New therapeutic antitubercular agents are urgent needed to control the global tuberculosis pandemic. We synthesized a new series of 4-carbonyl piperazine substituted 1,3-benzothiazin-4-one derivatives and evaluated their anti-mycobacterial activities against Mycobacterium tuberculosis H37Ra as well as their druggabilities. The results showed that most of these derivatives, especially the compounds with simple alkyl side chains, exhibited good antitubercular activities and favorable aqueous solubilities with no obvious cytotoxicity. It suggested that the 4-carbonyl piperazine substituents in benzothiazinone scaffold were well tolerated, in which the compound 8h, with an antitubercular activity of MIC 0.008 µM, exhibited an excellent aqueous solubility of 104 µg/mL, which was 100-fold better than the potent DprE1 inhibitor Comp.1 (BTZ038), also more soluble than PBTZ169.

Reductions in myeloid-derived suppressor cells and lung metastases using AZD4547 treatment of a metastatic murine breast tumor model.

BACKGROUND: AZD4547, a small-molecule inhibitor targeting the tyrosine kinase of Fibroblast Growth Factor Receptors (FGFRs), is currently under phase II clinical study for human subjects having breast cancer, while the underlying mechanism remains elusive. The aim of this study is to explore the potential mechanism by which AZD4547 inhibits breast tumor lung metastases at the level of the tumor microenvironment. METHODS: First, through in vitro experiments, we investigated the efficacy of the FGFRs inhibitor AZD4547 on 4T1 tumor cells for their proliferation, apoptosis, migration, and invasion. Second, by in vivo animal experiments, we evaluated the effects of AZD4547 on tumor growth and lung metastases in 4T1 tumor-bearing mice. Finally, we examined the impact of AZD4547 on the infiltration of myeloid-derived suppressor cells (MDSCs) in lung, spleens, peripheral blood and tumor. RESULTS: Through this study we found that AZD4547 could efficiently suppress tumor 4T1 cells through restraining their proliferation, blocking migration and invasion, and inducing apoptosis in vitro. In animal model we also demonstrated that AZD4547 was able to inhibit tumor growth and lung metastases, consistent with the decreased MDSCs accumulation in the tumor and lung tissues, respectively. Moreover, the reduced number of MDSCs in peripheral blood and spleens were also observed in the AZD4547-treated mice. Importantly, through the AZD4547 treatment, the CD4(+) and CD8(+) T-cells were significantly increased in tumor and spleens. CONCLUSION: Our studies showed that AZD4547 can inhibit breast cancer cell proliferation, induce its apoptosis and block migration and invasion in vitro and suppress tumor growth and lung metastases by modulating the tumor immunologic microenvironment in vivo.