Inhibition of SHP2 by new compounds induces differential effects on RAS/RAF/ERK and PI3K/AKT pathways in different cancer cell types

Discovery of a novel SHP2 allosteric inhibitor using virtual screening, FMO calculation, and molecular dynamic simulation

CONTEXT

SHP2 is a non-receptor protein tyrosine phosphatase to remove tyrosine phosphorylation. Functionally, SHP2 is an essential bridge to connect numerous oncogenic cell-signaling cascades including RAS-ERK, PI3K-AKT, JAK-STAT, and PD-1/PD-L1 pathways. This study aims to discover novel and potent SHP2 inhibitors using a hierarchical structure-based virtual screening strategy that combines molecular docking and the fragment molecular orbital method (FMO) for calculating binding affinity (referred to as the Dock-FMO protocol). For the SHP2 target, the FMO method prediction has a high correlation between the binding affinity of the protein-ligand interaction and experimental values (R2 = 0.55), demonstrating a significant advantage over the MM/PBSA (R2 = 0.02) and MM/GBSA (R2 = 0.15) methods. Therefore, we employed Dock-FMO virtual screening of ChemDiv database of ∼2,990,000 compounds to identify a novel SHP2 allosteric inhibitor bearing hydroxyimino acetamide scaffold. Experimental validation demonstrated that the new compound (E)-2-(hydroxyimino)-2-phenyl-N-(piperidin-4-ylmethyl)acetamide (7188-0011) effectively inhibited SHP2 in a dose-dependent manner. Molecular dynamics (MD) simulation analysis revealed the binding stability of compound 7188-0011 and the SHP2 protein, along with the key interacting residues in the allosteric binding site. Overall, our work has identified a novel and promising allosteric inhibitor that targets SHP2, providing a new starting point for further optimization to develop more potent inhibitors.

METHODS

All the molecular docking studies were employed to identify potential leads with Maestro v10.1. The protein-ligand binding affinities of potential leads were further predicted by FMO calculations at MP2/6-31G* level using GAMESS v2020 system. MD simulations were carried out with AmberTools18 by applying the FF14SB force field. MD trajectories were analyzed using VMD v1.9.3. MM/GB(PB)SA binding free energy analysis was carried out with the mmpbsa.py tool of AmberTools18. The docking and MD simulation results were visualized through PyMOL v2.5.0.

Tyrosine phosphatase PTPN11/SHP2 in solid tumors - bull's eye for targeted therapy?

Encoded by PTPN11, the Src-homology 2 domain-containing phosphatase 2 (SHP2) integrates signals from various membrane-bound receptors such as receptor tyrosine kinases (RTKs), cytokine and integrin receptors and thereby promotes cell survival and proliferation. Activating mutations in the PTPN11 gene may trigger signaling pathways leading to the development of hematological malignancies, but are rarely found in solid tumors. Yet, aberrant SHP2 expression or activation has implications in the development, progression and metastasis of many solid tumor entities. SHP2 is involved in multiple signaling cascades, including the RAS-RAF-MEK-ERK-, PI3K-AKT-, JAK-STAT- and PD-L1/PD-1- pathways. Although not mutated, activation or functional requirement of SHP2 appears to play a relevant and context-dependent dichotomous role. This mostly tumor-promoting and infrequently tumor-suppressive role exists in many cancers such as gastrointestinal tumors, pancreatic, liver and lung cancer, gynecological entities, head and neck cancers, prostate cancer, glioblastoma and melanoma. Recent studies have identified SHP2 as a potential biomarker for the prognosis of some solid tumors. Based on promising preclinical work and the advent of orally available allosteric SHP2-inhibitors early clinical trials are currently investigating SHP2-directed approaches in various solid tumors, either as a single agent or in combination regimes. We here provide a brief overview of the molecular functions of SHP2 and collate current knowledge with regard to the significance of SHP2 expression and function in different solid tumor entities, including cells in their microenvironment, immune escape and therapy resistance. In the context of the present landscape of clinical trials with allosteric SHP2-inhibitors we discuss the multitude of opportunities but also limitations of a strategy targeting this non-receptor protein tyrosine phosphatase for treatment of solid tumors.

Discovery of 1H-pyrazolo[3,4-b]pyrazine derivatives as selective allosteric inhibitor of protein tyrosine phosphatase SHP2 for the treatment of KRASG12C-mutant non-small cell lung cancer

The high expression or mutation of SHP2 can induce cancer, so targeting SHP2 has become a new strategy for cancer treatment. In this study, we used the previously reported SHP2 allosteric inhibitor IACS-13909 as a lead drug for structural derivation and modification, and synthesized three SHP2 inhibitors. Among them, 1H-pyrazolo[3,4-b]pyrazine derivative 4b was a highly selective SHP2 allosteric inhibitor, with an IC50 value of 3.2 nM, and its inhibitory activity was 17.75 times than that of the positive control IACS-13909. The cell proliferation experiment detected that compound 4b would markedly inhibit the proliferation of various cancer cells. Interestingly, compound 4b was highly sensitive to KRASG12C-mutant non-small cell lung cancer NCI-H358 cells, with an IC50 value of 0.58 μM and its antiproliferative activity was 4.79 times than that of IACS-13909. Furthermore, the combination therapy of compound 4b and KRASG12C inhibitor sotorasib would play a strong synergistic effect against NCI-H358 cells. The western blot experiment detected that compound 4b markedly downregulated the phosphorylation levels of ERK and AKT in NCI-H358 cells. Molecular docking study predicted that compound 4b bound to the allosteric site of SHP2 and formed H-bond interactions with key residues Thr108, Glu110, Arg111, and Phe113. In summary, this study aims to provide new ideas for the development of SHP2 allosteric inhibitors for the treatment of KRASG12C mutant non-small cell lung cancer.Communicated by Ramaswamy H. Sarma.

Design, synthesis and mechanistic anticancer activity of new acetylated 5-aminosalicylate-thiazolinone hybrid derivatives

The development of hybrid compounds has been widely considered as a promising strategy to circumvent the difficulties that emerge in cancer treatment. The well-established strategy of adding acetyl groups to certain drugs has been demonstrated to enhance their therapeutic efficacy. Based on our previous work, an approach of accommodating two chemical entities into a single structure was implemented to synthesize new acetylated hybrids (HH32 and HH33) from 5-aminosalicylic acid and 4-thiazolinone derivatives. These acetylated hybrids showed potential anticancer activities and distinct metabolomic profile with antiproliferative properties. The in-silico molecular docking predicts a strong binding of HH32 and HH33 to cell cycle regulators, and transcriptomic analysis revealed DNA repair and cell cycle as the main targets of HH33 compounds. These findings were validated using in vitro models. In conclusion, the pleiotropic biological effects of HH32 and HH33 compounds on cancer cells demonstrated a new avenue to develop more potent cancer therapies.

The design, synthesis, biological evaluation, and molecular docking of new 5-aminosalicylamide-4-thiazolinone hybrids as anticancer agents

New 5-aminosalicylamide-4-thiazolinone hybrids (27) were efficiently synthesized, characterized, and evaluated to explore their structure-activity relationship as anticancer agents. The antiproliferative activities of the new hybrids were evaluated against eight cancer cell lines using the sulforhodamine B assay. The most potent compound (24b) possessed high selectivity on the tested cell lines in the low micromolar range, with much lower effects on normal fibroblast cells (IC50 > 50 µM). The cell lines derived from leukemia (Jurkat), cervix (HeLa), and colon (HCT116) cancers appeared to be the most sensitive, with IC50 of 2 µM. 24b is the N-ethylamide derivative with p-dimethylaminobenzylidene at position 5 of the 4-thiazolinone moiety. Other N-substituents or arylidene derivatives showed lower activity. Hybrids with salicylamides showed lower activity than with methyl salicylate. The results clearly show that the modifications of the carboxy group and arylidene moiety greatly affect the activity. Investigating the possible molecular mechanisms of these hybrids revealed that they act through cell-cycle arrest and induction of apoptosis and epidermal growth factor receptor (EGFR) inhibition. Molecular docking studies rationalize the molecular interactions of 24b with EGFR. This work expands our knowledge of the structural requirements to improve the anticancer activity of 5-aminosalicylic-thiazolinone hybrids and pave the way toward multitarget anticancer salicylates.

SHP2 is involved in the occurrence, development and prognosis of cancer

Src homology-2 domain-containing protein tyrosine phosphatase (SHP2), encoded by protein tyrosine phosphatase non-receptor type 11 (PTPN11), is widely expressed in several human tissue types, and plays an important role in a variety of diseases. The present study assessed the impact of SHP2 on the occurrence, development and prognosis of solid tumors. The transcriptome sequencing data of 33 cancer types were downloaded from The Cancer Genome Atlas database. Clinical information of the corresponding patients, tumor mutational burden and information pertinent to microsatellite instability were also downloaded. The log-rank test and univariate Cox's regression test were used to evaluate patient survival. The 'ESTIMATE' method was used to assess the tumor microenvironment, and the 'CIBERSORT' algorithm was used to evaluate tumor immune cell infiltration. Spearman's correlation analysis was used to evaluate the correlation between SHP2 expression and the targets identified. ELISA was used to assess the SHP2 expression levels in peripheral blood samples of patients with breast, ovarian, endometrial and cervical cancer. The data indicated that the expression levels of SHP2 were increased in a variety of tumor tissues, and were associated with tumor progression and prognosis. In peripheral blood, the positive rates of SHP2 expression in breast cancer (71.43%) and ovarian cancer (58.82%) were significantly higher than those in the corresponding control groups. However, the positive rates of SHP2 expression in patients with endometrial cancer (31.03%) and cervical cancer (41.30%) were significantly lower than those in the corresponding control groups. Increased SHP2 expression improved overall survival (OS) and disease free survival (DFS) time in patients with kidney renal clear cell carcinoma. However, increased SHP2 expression reduced OS and DFS in patients with urothelial carcinoma, and cervical and endocervical cancer types. Moreover, the elevated expression of SHP2 could also reduce the OS of patients with breast invasive carcinoma, mesothelioma and liver hepatocellular carcinoma. PTPN11 expression was associated with the tumor microenvironment of various tumor types. The tumor mutational burden of various tumor types was associated with microsatellite instability. PTPN11 inhibited T-cell activation and promoted M2 macrophage activation in several tumors. Therefore, SHP2 may be used in the evaluation of tumor progression and prognosis, and it may be an optimal potential biological target for cancer therapy.

Differential dose-response effect of cyclosporine A in regulating apoptosis and autophagy markers in MCF-7 cells

Cyclosporine A (CsA) is an immunosuppressant primarily used at a higher dosage in transplant medicine and autoimmune diseases with a higher success rate. At lower doses, CsA exhibits immunomodulatory properties. CsA has also been reported to inhibit breast cancer cell growth by downregulating the expression of pyruvate kinase. However, differential dose-response effects of CsA in cell growth, colonization, apoptosis, and autophagy remain largely unidentified in breast cancer cells. Herein, we showed the cell growth-inhibiting effects of CsA by preventing cell colonization and enhancing DNA damage and apoptotic index at a relatively lower concentration of 2 µM in MCF-7 breast cancer cells. However, at a higher concentration of 20 µM, CsA leads to differential expression of autophagy-related genes ATG1, ATG8, and ATG9 and apoptosis-associated markers, such as Bcl-2, Bcl-XL, Bad, and Bax, indicating a dose-response effect on differential cell death mechanisms in MCF-7 cells. This was confirmed in the protein-protein interaction network of COX-2 (PTGS2), a prime target of CsA, which had close interactions with Bcl-2, p53, EGFR, and STAT3. Furthermore, we investigated the combined effect of CsA with SHP2/PI3K-AKT inhibitors showing significant MCF-7 cell growth reduction, suggesting its potential to use as an adjuvant during breast cancer therapy.

Ajuforrestin A, an Abietane Diterpenoid from Ajuga ovalifolia var. calanthe, Induces A549 Cell Apoptosis by Targeting SHP2

The Src-homology 2 domain-containing phosphatase 2 (SHP2), which is encoded by PTPN11, participates in many cellular signaling pathways and is closely related to various tumorigenesis. Inhibition of the abnormal activity of SHP2 by small molecules is an important part of cancer treatment. Here, three abietane diterpenoids, named compounds 1–3, were isolated from Ajuga ovalifolia var. calantha. Spectroscopic analysis was used to identify the exact structure of the compounds. The enzymatic kinetic experiment and the cellular thermal shift assay showed compound 2 selectively inhibited SHP2 activity in vitro. Molecular docking indicated compound 2 targeted the SHP2 catalytic domain. The predicted pharmacokinetic properties by SwissADME revealed that compound 2 passed the majority of the parameters of common drug discovery rules. Compound 2 restrained A549 proliferation (IC₅₀ = 8.68 ± 0.96 μM), invasion and caused A549 cell apoptosis by inhibiting the SHP2–ERK/AKT signaling pathway. Finally, compound 2 (Ajuforrestin A) is a potent and efficacious SHP2 inhibitor and may be a promising compound for human lung epithelial cancer treatment.

Dissecting protein tyrosine phosphatase signaling by engineered chemogenetic control of its activity

Protein tyrosine phosphatases (PTPases) are critical mediators of dynamic cell signaling. A tool capable of identifying transient signaling events downstream of PTPases is essential to understand phosphatase function on a physiological time scale. We report a broadly applicable protein engineering method for allosteric regulation of PTPases. This method enables dissection of transient events and reconstruction of individual signaling pathways. Implementation of this approach for Shp2 phosphatase revealed parallel MAPK and ROCK II dependent pathways downstream of Shp2, mediating transient cell spreading and migration. Furthermore, we show that the N-SH2 domain of Shp2 regulates MAPK-independent, ROCK II-dependent cell migration. Engineered targeting of Shp2 activity to different protein complexes revealed that Shp2-FAK signaling induces cell spreading whereas Shp2-Gab1 or Shp2-Gab2 mediates cell migration. We identified specific transient morphodynamic processes induced by Shp2 and determined the role of individual signaling pathways downstream of Shp2 in regulating these events. Broad application of this approach is demonstrated by regulating PTP1B and PTP-PEST phosphatases.

Knockdown of RNF183 suppressed proliferation of lung adenocarcinoma cells via inactivating the STAT3 signaling pathway

Proteins of the RNF183 (RING finger 183) family proteins have been reported to be of great importance in tumor the initiation and progression. However, the biological role and regulatory mechanism of RNF183 in non small cell lung cancer (NSCLC) development and progression are poorly defined. Hence, lung adenocarcinoma (LUAD) cell proliferation, cell apoptosis and cell cycle were measured using Cell Counting Kit-8 and flow cytometry analysis, respectively. The correlation between RNF183 and SHP2 (Src homology-2 domain-containing protein tyrosine phosphatase) was measured using coimmunoprecipitation and ubiquitination analysis in vitro. Tumor growth of NSCLC cells in vivo was measured using the nude mouse xenograft model. In this study, we verify that elevated RNF183 expression in tumor tissues of LUAD, origin from the TCGA, GEPIA, TIMER, and UALCAN database. RNF183 regulates apoptosis and cell cycle in vitro and tumor growth in vivo by activating the STAT3 pathway through ubiquitination of SHP2, a negative feedback regulator of the STAT3 pathway. Taken together, our results demonstrate that RNF183 regulates proliferation, apoptosis, and cell cycle in LUAD cells via modulation of SHP2/STAT3 signaling, suggesting the potential for targeting the RNF183-SHP2/STAT3 pathway for use in LUAD treatment.

Structure-based design, synthesis and biological evaluation of aminopyrazines as highly potent, selective, and cellularly active allosteric SHP2 inhibitors

Src homology-2-containing protein tyrosine phosphatase 2 (SHP2) encoded by the proto-oncogene PTPN11 is the first identified non-receptor protein tyrosine phosphatase. SHP2 dysregulation contributes to the pathogenesis of different cancers, making SHP2 a promising therapeutic target for cancer therapy. In this article, we report the structure-guided design based on the well-characterized SHP2 inhibitor SHP099, extensive structure-activity relationship studies (SARs) of aminopyrazines, biochemical characterization and cellular potency. These medicinal chemistry efforts lead to the discovery of the lead compound TK-453, which potently inhibits SHP2 (SHP2^WT IC₅₀ = 0.023 μM, ΔTm = 7.01 °C) in a reversible and noncompetitive manner. TK-453 exhibits high selectivity over SHP2^PTP, SHP1 and PTP1B, and may bind at the "tunnel" allosteric site of SHP2 as SHP099. As the key pharmacophore, the aminopyrazine scaffold not only reorganizes the cationic-π stacking interaction with R111 via the novel hydrogen bond interaction between the S atom of thioether linker and T219, but also mediates a hydrogen bond with E250. In vitro studies indicate that TK-453 inhibits proliferation of HeLa, KYSE-70 and THP-1 cells moderately and induces apoptosis of Hela cells. Further mechanistic studies suggest that TK-453 can decrease the phosphorylation levels of AKT and Erk1/2 in HeLa and KYSE-70 cells. Collectively, TK-453 is a highly potent, selective, and cellularly active allosteric SHP2 inhibitor that modulates the phosphorylation of SHP2-mediated AKT and Erk cell signaling pathways by inhibiting the phosphatase activity of SHP2.

SHP2 Targets ITK Downstream of PD-1 to Inhibit T Cell Function

PD-1 is a critical therapeutic target in cancer immunotherapy and antibodies blocking PD-1 are approved for multiple types of malignancies. The phosphatase SHP2 is the main effector mediating PD-1 downstream signaling and accordingly attempts have been made to target this enzyme as an alternative approach to treat immunogenic tumors. Unfortunately, small molecule inhibitors of SHP2 do not work as expected, suggesting that the role of SHP2 in T cells is more complex than initially hypothesized. To better understand the perplexing role of SHP2 in T cells, we performed interactome mapping of SAP, an adapter protein that is associated with SHP2 downstream signaling. Using genetic and pharmacological approaches, we discovered that SHP2 dephosphorylates ITK specifically downstream of PD-1 and that this event was associated with PD-1 inhibitory cellular functions. This study suggests that ITK is a unique target in this pathway, and since ITK is a SHP2-dependent specific mediator of PD-1 signaling, the combination of ITK inhibitors with PD-1 blockade may improve upon PD-1 monotherapy in the treatment of cancer.

Allosteric Inhibitors of SHP2: An Updated Patent Review (2015-2020)

Srchomology-2-domain-containing PTP 2 (SHP2) is a nonreceptor phosphatase encoded by the PTPN11 gene. Over expression of SHP2 is associated with various human diseases, such as Noonan syndrome, LEOPARD syndrome, and cancers. To overcome the shortcomings of existing orthosteric inhibitors, novel inhibitors targeting the allosteric site of SHP2 with high selectivity and low toxicity are under development. This paper reviews allosteric inhibitors of SHP2 published in patents from 2015 to 2020. The molecules are classified according to the chemical structure of the central core. SHP2 has long been considered as an 'undruggable' protein. Fortunately, a critical breakthrough was made by researchers from Novartis AG Ltd., who identified SHP099 as a highly potent, selective, soluble, and orally bioavailable SHP2 allosteric inhibitor. Currently, there are several allosteric inhibitors of SHP2 in clinical development. However, drug resistance is still a major challenge. The combination of SHP2 allosteric inhibitors and immunotherapy drugs or molecular targeted drugs is emerging as a promising therapeutic strategy against drug resistance.

Health benefits of cyanidin-3-glucoside as a potent modulator of Nrf2-mediated oxidative stress

Berries are natural sources of anthocyanins, especially cyanidin-3-glucoside (C3G), and exhibit significant antioxidant, antidiabetic, anti-inflammatory, and cytoprotective effects against various oxidative stress-induced disorders. C3G and its metabolites possess higher absorption and bioavailability, and interaction with gut microbiota may enhance their health benefits. Various in vitro studies have shown the reactive oxygen species (ROS)-mitigating potential of C3G. However, in in vivo models, C3G exerts its cytoprotective properties by regulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant-responsive element (ARE) pathway. Despite existing reports stating various health benefits of C3G, its antioxidant potential by modulating the Nrf2 pathway remains less identified. This review discusses the Nrf2-mediated antioxidant response of C3G in modulating oxidative stress against DNA damage, apoptosis, carcinogen toxicity, and inflammatory conditions. Furthermore, we have reviewed the recent clinical trial data to establish cross talk between a berry-rich diet and disease prevention.

A multifunctional cross-validation high-throughput screening protocol enabling the discovery of new SHP2 inhibitors

The protein tyrosine phosphatase Src homology phosphotyrosyl phosphatase 2 (SHP2) is implicated in various cancers, and targeting SHP2 has become a promising therapeutic approach. We herein described a robust cross-validation high-throughput screening protocol that combined the fluorescence-based enzyme assay and the conformation-dependent thermal shift assay for the discovery of SHP2 inhibitors. The established method can effectively exclude the false positive SHP2 inhibitors with fluorescence interference and was also successfully employed to identify new protein tyrosine phosphatase domain of SHP2 (SHP2-PTP) and allosteric inhibitors. Of note, this protocol showed potential for identifying SHP2 inhibitors against cancer-associated SHP2 mutation SHP2-E76A. After initial screening of our in-house compound library (∼2300 compounds), we identified 4 new SHP2-PTP inhibitors (0.17% hit rate) and 28 novel allosteric SHP2 inhibitors (1.22% hit rate), of which SYK-85 and WS-635 effectively inhibited SHP2-PTP (SYK-85: IC50 = 0.32 μmol/L; WS-635: IC50 = 4.13 μmol/L) and thus represent novel scaffolds for designing new SHP2-PTP inhibitors. TK-147, an allosteric inhibitor, inhibited SHP2 potently (IC50 = 0.25 μmol/L). In structure, TK-147 could be regarded as a bioisostere of the well characterized SHP2 inhibitor SHP-099, highlighting the essential structural elements for allosteric inhibition of SHP2. The principle underlying the cross-validation protocol is potentially feasible to identify allosteric inhibitors or those inactivating mutants of other proteins.

Natural compound catechol induces DNA damage, apoptosis, and G1 cell cycle arrest in breast cancer cells

Targeting cell cycle and inducing DNA damage by activating cell death pathways are considered as effective therapeutic strategy for combating breast cancer progression. Many of the naturally known small molecules target these signaling pathways and are effective against resistant and/or aggressive types of breast cancers. Here, we investigated the effect of catechol, a naturally occurring plant compound, for its specificity and chemotherapeutic efficacies in breast cancer (MCF-7 and MDA-MB-231) cells. Catechol treatment showed concentration-dependent cytotoxicity and antiproliferative growth in both MCF-7 and MDA-MB-231 cells while sparing minimal effects on noncancerous (F-180 and HK2) cells. Catechol modulated differential DNA damage effects by activating ATM/ATR pathways and showed enhanced γ-H2AX expression, as an indicator for DNA double-stranded breaks. MCF-7 cells showed G1 cell cycle arrest by regulating p21-mediated cyclin E/Cdk2 inhibition. Furthermore, activation of p53 triggered a caspase-mediated cell death mechanism by inhibiting regulatory proteins such as DNMT1, p-BRCA1, MCL-1, and PDCD6 with an increased Bax/Bcl-2 ratio. Overall, our results showed that catechol possesses favorable safety profile for noncancerous cells while specifically targeting multiple signaling cascades to inhibit proliferation in breast cancer cells.

Emerging chemical scaffolds with potential SHP2 phosphatase inhibitory capabilities - A comprehensive review

The drug discovery panorama is cluttered with promising therapeutic targets that have been deserted because of inadequate authentication and screening failures. Molecular targets formerly tagged as "undruggable" are nowadays being more cautiously cross-examined, and whilst they stay intriguing, numerous targets are emerging more accessible. Protein tyrosine phosphatases (PTPs) excellently exemplifies a class of molecular targets that have transpired as druggable, with several small molecules and antibodies recently turned available for further development. In this respect, SHP2, a PTP, has emerged as one of the potential targets in the current pharmacological research, particularly for cancer, due to its critical role in various signalling pathways. Recently, few molecules with excellent potency have entered clinical trials, but none could reach the clinic. Consequently, search for novel, non-toxic, and specific SHP2 inhibitors are on purview. In this review, general aspects of SHP2 including its structure and mechanistic role in carcinogenesis have been presented. It also sheds light on the development of novel molecular architectures belonging to diverse chemical classes that have been proposed as SHP2-specific inhibitors along with their structure-activity relationships (SARs), stemming from chemical, mechanism-based and computer-aided studies reported since January 2015 to July 2020 (excluding patents), focusing on their potency and selectivity. The encyclopedic facts and discussions presented herein will hopefully facilitate researchers to design new ligands with better efficacy and selectivity against SHP2.

5-Arylidene-2-(4-hydroxyphenyl)aminothiazol-4(5H)-ones with selective inhibitory activity against some leukemia cell lines

The data on the pharmacology of 4-thiazolidinones showed that 5-ene-2-(imino)amino-4-thiazolidinones are likely to comprise one of the most promising groups of compounds possessing anticancer properties. A series of 5-arylidene-2-(4-hydroxyphenyl)aminothiazol-4(5H)-ones was designed, synthesized, and studied against 10 leukemia cell lines, including the HL-60, Jurkat, K-562, Dami, KBM-7, and some Ba/F3 cell lines. The structure-activity relationship analysis shows that almost all tested 5-arylidene-2-(4-hydroxyphenyl)aminothiazol-4(5H)-ones were characterized by ІС₅₀ values lower or comparable to that of the control drug chlorambucil. Among the tested compounds, (5Z)-5-(2-methoxybenzylidene)- (12), (5Z)-(2-ethoxybenzylidene)- (21), (5Z)-5-(2-benzyloxybenzylidene)- (25), and (5Z)-5-(2-allyloxybenzylidene)-2-(4-hydroxyphenylamino)thiazol-4(5H)-ones (28) possessed the highest antileukemic activity at submicromolar concentrations (ІС₅₀  = 0.10-0.95 µM).

SHP2 knockdown ameliorates liver insulin resistance by activating IRS-2 phosphorylation through the AKT and ERK1/2 signaling pathways

Diabetes is a chronic metabolic disease characterized by insulin resistance (IR). SHP2 has previously been identified as a potential target to reduce IR in diabetes. Here, we examined the effects of SHP2 on glucose consumption (GC), IR level and the expression of insulin receptor substrate (IRS), AKT and extracellular signal-regulated kinase (ERK)1/2 proteins in a cellular and animal model of diabetes. IR was induced in hepatocellular carcinoma (HCC) cells, and SHP2 was up-regulated or down-regulated in cells. Diabetic rats were treated with SHP2 inhibitor. GC of cells, and the weight, total cholesterol, triglycerides, fasting blood glucose, fasting insulin, homeostasis model assessment-IR index and insulin sensitivity (ISI) of the rats were analyzed. The levels of SHP2 and the activation of IRS-2, AKT and ERK1/2 in cells and rats were measured by quantitative real-time PCR (qRT-PCR) or western blot. GC was reduced, but expression of SHP2 was enhanced in IR HCC cells. Phosphorylation of IRS-2 and AKT in IR HCC cells and diabetic rats was decreased, whereas phosphorylation of ERK1/2 was enhanced. In both the cell and animal models, SHP2 knockdown enhanced GC, ameliorated IR, activated IRS-2 and AKT, and inhibited ERK1/2 phosphorylation, in contrast with the effects of SHP2 overexpression. SHP2 knockdown may enhance GC and ameliorate IR through phosphorylation of IRS-2 via regulating AKT and ERK1/2 in liver.

A novel function of IMPA2, plays a tumor-promoting role in cervical cancer

Discovery of genes and molecular mechanism involved in cervical cancer development would promote the prevention and treatment. By comparing gene expression profiles of cervical carcinoma in situ (CCIS) and adjacent normal tissues, we identified a potential cancer-promoting gene, IMPA2. This study aimed to elucidate the role of IMPA2 and underlying molecular mechanisms in cervical cancer progression. To do this expression of IMPA2 was compared between human cervical cancer and corresponding adjacent normal cervical tissues firstly. CCK-8 assay, clone formation assay, wound healing assay, transwell assay, and tumor formation in nude mice were performed to demonstrate the effect of IMPA2 in cervical cancer proliferation and metastasis. Further proteomic profiling and western blotting explored the molecular pathway involved in the IMPA2-regulating process. The results showed that IMPA2 gene expression was upregulated in cervical cancer. Consistently, silencing of IMPA2 suppressed tumor formation in BALB/c nude mice. Short hairpin RNA (shRNA)-mediated IMPA2 silencing significantly inhibited proliferation and colony-forming abilities of cervical cancer cells, while IMPA2 overexpression had little impact. Also, IMPA2 silencing suppressed cellular migration, but overexpression promoted migration. Proteomics analysis revealed the involvement of mitogen-activated protein kinase (MAPK) pathway in tumor-promoting action of IMPA2. Significantly, the inhibition of IMPA2 activated ERK phosphorylation, and its inhibitory effects can be restored by using selective ERK inhibitor, FR180204. In conclusion, IMPA2 acts as an oncogene in the proliferation and migration of cervical cancer. IMPA2 downregulated ERK phosphorylation to promote cervical cancer. These findings identify a new mechanism underlying cervical cancer and suggest a regulating effect of IMPA2 in MAPK signaling pathway.

Biological Evaluation of Newly Synthesized Biaryl Guanidine Derivatives to Arrest β-Secretase Enzymatic Activity Involved in Alzheimer’s Disease

Proteases BACE1 (β-secretases) enzymes have been recognized as a promising target associated with Alzheimer's disease (AD). This study was carried out on the principles of molecular docking, chemical synthesis, and enzymatic inhibition of BACE1 enzymes via biaryl guanidine-based ligands. Based on virtual screening, thirteen different compounds were synthesized and subsequently evaluated via in vitro and in vivo studies. Among them, 1,3-bis(5,6-difluoropyridin-3-yl)guanidine (compound (9)) was found the most potent (IC₅₀ = 97 ± 0.91 nM) and active to arrest (99%) β-secretase enzymes (FRET assay). Furthermore, it was found to improve the novel object recognition test and Morris water maze test significantly (p < 0.05). Improved pharmacokinetic parameters, viz., Log P_o/w (1.76), Log S (-2.73), and better penetration to the brain (BBB permeation) with zero Lipinski violation, made it possible to hit the BACE1 as a potential therapeutic source for AD.

PCC0208023, a potent SHP2 allosteric inhibitor, imparts an antitumor effect against KRAS mutant colorectal cancer

The non-receptor tyrosine phosphatase SHP2, encoded by PTPN11, plays an indispensable role in tumors driven by oncogenic KRAS mutations, which frequently occur in colorectal cancer. Here, PCC0208023, a potent SHP2 allosteric inhibitor, was synthesized to evaluate its inhibitory effects against the SHP2 enzyme, and the KRAS mutant colorectal cancer in vitro and in vivo, and its impart on the RAS/MAPK pathway. Consistent with an allosteric mode of inhibition, PCC0208023 can non-competitively inhibit the activity of full-length SHP2 enzyme, but lacks activity against the free catalytic domain of SHP2. Furthermore, PCC0208023 inhibited the proliferation of KRAS mutation-driven human colorectal cancer cells by inhibiting the RAS/MAPK signaling pathway in vitro. Importantly, PCC0208023 displayed good anti-tumor efficacy against KRAS-driven LS180 and HCT116 xenograft models in nude mice with the decreased Ki67 and p-ERK level, and increased cleaved caspase-3 expression in tumors. Interestingly, PCC0208023 maintained high levels in LS180 tumors within 24 h after administration and was mainly distributed in both intestines and lungs. Molecular docking studies revealed a higher affinity of PCC0208023 with key residues in the SHP2 allosteric pocket than RMC-4550. PCC0208023 deserves further optimization to identify additional low-toxic and potent SHP2 allosteric inhibitors with novel scaffolds for the treatment of patients with KRAS mutation-positive colorectal cancer.