Blocking the PD-1 signal transduction by occupying the phosphorylated ITSM recognition site of SHP-2.

Targeting the PD-1/PD-L1 axis with small-molecular inhibitors is a promising approach for immunotherapy. Here, we identify a natural pentacyclic triterpenoid, Pygenic Acid A (PA), as a PD-1 signaling inhibitor. PA exerts anti-tumor activity in hPD-1 knock-in C57BL/6 mice and enhances effector functions of T cells to promote immune responses by disrupting the PD-1 signaling transduction. Furthermore, we identify SHP-2 as the direct molecular target of PA for inhibiting the PD-1 signaling transduction. Subsequently, mechanistic studies suggest that PA binds to a new druggable site in the phosphorylated PD-1 ITSM recognition site of SHP-2, inhibiting the recruitment of SHP-2 by PD-1. Taken together, our findings demonstrate that PA has a potential application in cancer immunotherapy and occupying the phosphorylated ITSM recognition site of SHP-2 may serve as an alternative strategy to develop PD-1 signaling inhibitors. In addition, our success in target recognition provides a paradigm of target identification and confirmation for natural products.

Design, synthesis, and biological evaluation of diphenyl ether substituted quinazolin-4-amine derivatives as potent EGFRL858R/T790M/C797S inhibitors.

Epidermal growth factor receptor (EGFR) is a validated target for non-small-cell lung cancer (NSCLC). However, the treatment for EGFR-C797S mutation induced by third-generation EGFR inhibitors remains a concern. Therefore, the development of the fourth-generation EGFR inhibitors to overcome the EGFR-C797S mutation has great potential for clinical treatment. In this article, we designed and synthesized a series of diphenyl ether substituted quinazolin-4-amine derivatives that simultaneously occupy the ATP binding pocket and the allosteric site of EGFR. Among the newly synthesized compounds, 9d displayed excellent kinase activity against EGFRL858R/T790M/C797S with an IC50 value of 0.005 µM, and exhibited anti-proliferation activity in BaF3-EGFRL858R/T790M/C797S cells with the IC50 value of 0.865 µM. Furthermore, 9d could suppress phosphorylation of EGFR and induce cell apoptosis and cycle arrest at G2 phase in a dose-dependent manner in BaF3-EGFRL858R/T790M/C797S cells. More importantly, 9d displayed significant antitumor effects in BaF3-EGFRL858R/T790M/C797S xenograft mouse model (30 mg/kg, TGI = 71.14 %). All the results indicated compound 9d might be a novel fourth-generation EGFR inhibitor for further development in overcoming the EGFR-C797S resistance mutation.

Discovery of Novel Non-Nucleoside Inhibitors Interacting with Dizinc Ions of CD73.

High extracellular concentrations of adenosine triphosphate (ATP) in the tumor microenvironment generate adenosine by sequential dephosphorylation of CD39 and CD73, resulting in potent immunosuppression to inhibit T cell and natural killer (NK) cell function. CD73, as the determining enzyme for adenosine production, has been shown to correlate with poor clinical tumor prognosis. Conventional inhibitors as analogues of adenosine 5'-monophosphate (AMP) may have a risk of further metabolism to adenosine analogues. Here, we report a new series of malonic acid non-nucleoside inhibitors coordinating with zinc ions of CD73. Compound 12f was found to be a superior CD73 inhibitor (IC50 = 60 nM) by structural optimization, and its pharmacokinetic properties were investigated. In mouse tumor models, compound 12f showed excellent efficacy and reversal of immunosuppression in combination with chemotherapeutic agents or checkpoint inhibitors, suggesting that it deserves further development as a novel CD73 inhibitor.

Naphtho[1,8-ef]isoindole-7,8,10(9H)-trione as Novel Theranostic Agents for Photodynamic Therapy and Multi-Subcellular Organelles Localization.

A series of naphtho[1,8-ef]isoindole-7,8,10(9H)-trione derivatives as novel theranostic agents for photodynamic therapy and multi-subcellular organelles localization were designed and synthesized. Most of them possess moderate fluorescence quantum yield and long wavelength absorption simultaneously, which made them possible for dual effects of imaging and therapy. Notably, compounds 7 b and 7 d exhibited significant light-toxicity but slight dark-toxicity. Confocal fluorescence microscopy experiments demonstrated that compound 7 b can locate and image in special multi-subcellular organelles. All the research results implied that naphtho[1,8-ef] isoindole-7,8,10(9H)-trione derivatives can be applied as a new series of theranostic agents with the characteristics of photodynamic therapy and multi-subcellular organelles imaging.

A simple monoselective C-H oxygenation approach for the synthesis of ursane triterpenoids.

Herein, we presented a simple approach for C-H oxidation in the C23 or/and C24 of ursane triterpenoids without any protection of a Δ12,13 double bond. As a result, from commercial ursolic acid (UA), six naturally occurring ursane triterpenoids were synthesized in overall yields of 3.4% to 36.8%, which implied the importance of this approach for the derivation of natural products and their application in biological activity.

Discovery and optimization of 4-anilinoquinazoline derivatives spanning ATP binding site and allosteric site as effective EGFR-C797S inhibitors.

Epidermal growth factor receptor (EGFR) is an effective drug target for the treatment of non-small cell lung cancer (NSCLC). However, a tertiary point mutation (C797S) at the ATP binding pocket of the EGFR induces resistance to the third-generation EGFR inhibitors, due to the loss of covalent interaction with Cys797. Here, we designed a series of 4-anilinoquinazoline derivatives that simultaneously occupied the ATP binding pocket and the allosteric site. The newly-synthesized compounds displayed high potency against EGFR-C797S resistance mutation. Among them, compound 14d presented high anti-proliferative effect against BaF3-EGFRL858R/T790M/C797S (IC50 = 0.75 µM) and BaF3-EGFR19del/T790M/C797S (IC50 = 0.09 µM) cells. Moreover, 14d resulted in obvious inhibition activities against EGFR and its downstream signaling pathways in a dose-dependent manner in BaF3-EGFR19del/T790M/C797S cells. Finally, 14d significantly inhibited tumor growth in BaF3-EGFR19del/T790M/C797S xenograft model (30 mg/kg, TGI = 67.95%). These results demonstrated that 14d is a novel and effective EGFR-C797S inhibitor which spanning the ATP binding pocket and the allosteric site and effective both in vitro and in vivo.

Anti-inflammatory Effects of a Small Molecule Gastrin-Releasing Peptide Receptor Antagonist on Adjuvant-Induced Rheumatoid Arthritis in Rats.

The anti-inflammatory effects of (R)-2-(1H-Imidazol-1-yl) ethyl-3-(1H-indol-3-yl)-2-(2-p-tolylacetamido)propanamide (RH-1402), a previous designed small molecule Gastrin releasing peptide (GRP) antagonist were evaluated in adjuvant-induced arthritic model of rats, and the inhibitory effect on neutrophil migration induced by GRP was determined by a transwell system experiment in vitro. The arthritis was induced by injection of Complete Freund's Adjuvant (CFA) containing 10 mg/mL of heat killed mycobacterium into the left hind footpad. Experimental rats were randomly divided into 6 groups, including control, placebo, positive control group, RH-1402 of low/middle/high dose group. Disease incidence and severity was evaluated through scoring of the paw edema and histologic features of joint synovial. Blood of all experimental rats was collected for interleukin 1ß (IL-1ß) and tumor necrosis factor α (TNF-α) cytokine levels. A transwell system was used to investigate whether RH-1402 would inhibit neutrophils migrating up a gradient of GRP in vitro. RH-1402 (5 and 10 mg/kg) significantly decreased adjuvant induced increased arthritis index during the administration period (days 14-20). Significant inhibition of joint synovial histological features can be found in the RH-1402 treated group, including alleviated Hyperplasia, Inflammatory of infiltration and activation of pannus formation. It also suppressed TNF-α and IL-1ß level. Five and 10 mg/kg of RH-1402 significantly inhibited the effect of GRP on neutrophil migration with a dose dependent relationship. These findings indicate that RH-1402 have potential protective anti-inflammatory effects on experimental models of arthritis.