Design and synthesis of improved active-site SHP2 inhibitors with anti-breast cancer cell effects

A high throughput assay for phosphoribosylformylglycinamidine synthase

Metabolic reprogramming of purine biosynthesis is a hallmark of cancer metabolism and represents a critical vulnerability. The enzyme phosphoribosylformylglycinamidine synthase (PFAS) catalyzes the fourth step in de novo purine biosynthesis and has been demonstrated to be prognostic for survival of liver cancer. Despite the importance of this protein as a drug target, there are no known specific inhibitors of PFAS activity. Here, we describe a new continuous, spectrophotometric assay for the synthase domain of PFAS that is amenable to high-throughput screening (HTS). This mechanism-based fluorescent assay makes use of the acid phosphatase substrate, 6,8-difluoro-4-methylumbelliferyl phosphate (DiFMUP). PFAS catalyzes the turnover of DiFMUP with a KM of 108 ± 7 µM. After optimization and miniaturization of the assay for 1,536-well format, we conducted a pilot HTS using the LOPAC1280 library. The assay performed extremely well, with an average Z' of 0.94 ± 0.02, average signal to noise of 5.01 ± 0.06, excellent inter plate correlation, and a hit rate of 1.18 %. This assay provides a critically needed tool to advance the study of PFAS enzymology and will be foundational for the discovery of small molecule inhibitors both as functional probes and for the basis of new drug development.

Discovery of novel substituted pyridine carboxamide derivatives as potent allosteric SHP2 inhibitors

Src homology-2-containing protein tyrosine phosphatase 2 (SHP2), a critical regulator of proliferation pathways and immune checkpoint signaling in various cancers, is an attractive target for cancer therapy. Here, we report the discovery of a novel series of substituted pyridine carboxamide derivatives as potent allosteric SHP2 inhibitors. Among them, compound C6 showed excellent inhibitory activity against SHP2 and antiproliferative effect on MV-4-11 cell line with IC50 values of 0.13 and 3.5 nM, respectively. Importantly, orally administered C6 displayed robust in vivo antitumor efficacy in the MV-4-11 xenograft mouse model (TGI = 69.5 %, 30 mg/kg). Subsequent H&E and Ki67 staining showed that C6 significantly suppressed the proliferation of tumor cells. Notably, flow cytometry, ELISA and immunofluorescence experiments showed that C6 remarkably decreased the population of CD206+/Ly6C+ M2-like tumor-associated macrophages (TAMs), the expression level of interleukin-10 (IL-10), and the number of F4/80+/CD206+ M2-like TAMs, suggesting that C6 could effectively alleviate the activation and infiltration of M2-like TAMs. Taken together, these results illustrate that C6 is a promising SHP2 inhibitor worthy of further development.

Crystal structure of an aceto-nitrile solvate of 2-(3,4,5-triphen-ylphen-yl)acetic acid

Crystal growth of 2-(3,4,5-triphen-ylphen-yl)acetic acid (1) from aceto-nitrile yields a monosolvate, C26H20O2·CH3CN, of the space group P1. In the crystal, the title mol-ecule adopts a conformation in which the three phenyl rings are arranged in a paddlewheel-like fashion around the central arene ring and the carboxyl residue is oriented nearly perpendicular to the plane of this benzene ring. Inversion-symmetric dimers of O-H⋯O-bonded mol-ecules of 1 represent the basic supra-molecular entities of the crystal structure. These dimeric mol-ecular units are further linked by C-H⋯O=C bonds to form one-dimensional supra-molecular aggregates running along the crystallographic [111] direction. Weak Car-yl-H⋯N inter-actions occur between the mol-ecules of 1 and aceto-nitrile.

Small Molecule SHP2 Inhibitor LXQ-217 Affects Lung Cancer Cell Proliferation in Vitro and in Vivo

BACKGROUND

SHP2 is highly expressed in a variety of cancer and has emerged as a potential target for cancer therapeutic agents. The identification of uncharged pTyr mimics is an important direction for the development of SHP2 orthosteric inhibitors.

METHODS

Surface plasmon resonance analysis and cellular thermal shift assay were employed to verify the direct binding of LXQ-217 to SHP2. The inhibitory effect of LXQ-217 was characterized by linear Weaver-Burke enzyme kinetic analysis and BIOVIA Discovery Studio. The inhibition of tumor cell proliferation by LXQ-217 was characterized by cell viability assay, colony formation assays and hoechst 33258 staining. The inhibition of lung cancer proliferation in vivo was studied in nude mice after oral administration of LXQ-217.

RESULTS

An electroneutral bromophenol derivative, LXQ-217, was identified as a competitive SHP2 inhibitor. LXQ-217 induced apoptosis and inhibited growth of human pulmonary epithelial cells by affecting the RAS-ERK and PI3 K-AKT signaling pathways. Long-term oral administration of LXQ-217 significantly inhibited the proliferation ability of lung cancer cells in nude mice. Moreover, mice administered LXQ-217 orally at high doses exhibited no mortality or significant changes in vital signs.

CONCLUSIONS

Our findings on the uncharged orthosteric inhibitor provide a foundation for further development of a safe and effective anti-lung cancer drug.