Modification of osimertinib to discover new potent EGFRC797S-TK inhibitors.

The EGFRC797S mutation is a dominant mechanism of acquired resistance after the treatment of non-small cell lung cancer (NSCLC) with osimertinib in clinic. To date, there is no inhibitor approved to overcome the resistance caused by osimertinib. In this study, a series of compounds with phenylamino-pyrimidine scaffold deriving from osimertinib were designed, synthesized and evaluated as fourth-generation EGFRC797S-TK inhibitors. Consequently, compound Os30 exhibited potent inhibitory activities against both EGFRDel19/T790M/C797S TK and EGFRL858R/T790M/C797S TK with IC50 values of 18 nM and 113 nM, respectively. Moreover, Os30 can powerfully inhibit the proliferation of KC-0116 (BaF3-EGFRDel19/T790M/C797S) and KC-0122 (BaF3-EGFRL858R/T790M/C797S) cells. In addition, Os30 can suppress EGFR phosphorylation in a concentration-dependent manner in KC-0116 cells, arrest KC-0116 cells at G1 phase and induce the apoptosis of KC-0116 cells. More importantly, Os30 showed potent antitumor efficacy in the KC-0116 cells xenograft nude mice tumor model with the tumor growth inhibitory rate of 77.6% at a dosage of 40 mg/kg. These findings demonstrate that modification of osimertinib can discover new potent EGFRC797S-TK inhibitors, and compound Os30 is a potent fourth-generation EGFR inhibitor to treat NSCLC with EGFmRC797S mutation.

Design, synthesis and evaluation of new pyrimidine derivatives as EGFRC797S tyrosine kinase inhibitors.

The clinical use of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in the treatment of non-small cell lung cancer was limited by the drug resistance caused by EGFRC797S mutation. Therefore, in order to overcome the drug resistance, we designed and synthesized a series of 2-aminopyrimidine derivatives as EGFRC797S-TKIs. Among these compounds, compounds A5 and A13 showed significant anti-proliferative activity against the KC-0116 (EGFRdel19/T790M/C797S) cell line with high selectivity. A5 inhibited EGFR phosphorylation and induced apoptosis of KC-0116 cell, arrested KC-0116 cell at G2/M phase. Molecular docking results showed that A5 and brigatinib bind to EGFR in a similar pattern. In addition to forming two important hydrogen bonds with Met793 residue, A5 also formed a hydrogen bond with Lys745 residues, which may play an important role for the potent inhibitory activity against EGFRdel19/T790M/C797S. Based on these results, A5 turned out to be effective reversible EGFRC797S-TKIs which can be further developed.

Discovery of Potent PROTACs Targeting EGFR Mutants through the Optimization of Covalent EGFR Ligands.

Drug resistance caused by epidermal growth factor receptor (EGFR) mutation has largely limited the clinical use of EGFR tyrosine kinase inhibitors (EGFR-TKIs) for the treatment of non-small-cell lung cancer (NSCLC). Herein, to overcome the intractable problem of drug resistance, proteolysis targeting chimeras (PROTACs) targeting EGFR mutants were developed by optimizing covalent EGFR ligands. Covalent or reversible covalent pyrimidine- or purine-containing PROTACs were designed, synthesized, and evaluated. As a consequence, covalent PROTAC CP17, with a novel purine-containing EGFR ligand, was discovered as a highly potent degrader against EGFRL858R/T790M and EGFRdel19, reaching the lowest DC50 values among all reported EGFR-targeting PROTACs. Furthermore, CP17 exhibited excellent cellular activity against the H1975 and HCC827 cell lines with high selectivity. Mechanism investigation indicated that the lysosome was involved in the degradation process. Importantly, the covalent binding strategy was proven to be an effective approach for the design of PROTACs targeting EGFRL858R/T790M, which laid the practical foundation for further development of potent EGFR-targeting PROTACs.

The anti-neoplastic activities of aloperine in HeLa cervical cancer cells are associated with inhibition of the IL-6-JAK1-STAT3 feedback loop.

Cervical cancer (CC) is recognized as the most common neoplasm in the female reproductive system worldwide. The lack of chemotherapeutic agents with outstanding effectiveness and safety severely compromises the anti-cipated prognosis of patients. Aloperine (ALO) is a natural quinolizidine alkaloid with marked anti-cancer effects on multiple malignancies as well as favorable activity in relieving inflammation, allergies and infection. However, its therapeutic efficacy and underlying mechanism in CC are still unclear. In the current study, MTT assay was employed to evaluate the viability of HeLa cells exposed to ALO to preliminarily estimate the effectiveness of ALO in CC. Then, the effects of ALO on the proliferation and apoptosis of HeLa cells were further investigated by plate colony formation and flow cytometry, respectively, while the migration and invasion of ALO-treated HeLa cells were evaluated using Transwell assay. Moreover, nude mice were subcutaneously inoculated with HeLa cells to demonstrate the anti-CC properties of ALO in vivo. The molecular mechanisms underlying these effects of ALO were evaluated by Western blot and immunohistochemical analysis. This study experimentally demonstrated that ALO inhibited the proliferation of HeLa cells via G2 phase cell cycle arrest. Simultaneously, ALO promoted an increase in the percentage of apoptotic HeLa cells by increasing the Bax/Bcl-2 ratio. Additionally, the migration and invasion of HeLa cells were attenuated by ALO treatment, which was considered to result from inhibition of epithelial-to-mesenchymal transition. For molecular mechanisms, the expression and activation of the IL-6-JAK1-STAT3 feedback loop were markedly suppressed by ALO treatment. This study indicated that ALO markedly suppresses the proliferation, migration and invasion and enhances the apoptosis of HeLa cells. In addition, these prominent anti-CC properties of ALO are associated with repression of the IL-6-JAK1-STAT3 feedback loop.

[Bioremediation potential of Apostichopus japonicus (Selenka) in coastal bivalve suspension aquaculture system].

Suspension aquaculture of filter-feeding bivalves can produce large amount of faeces and pseudofaeces (biodeposits) that may impact aquaculture environment, while deposit-feeding sea cucumbers may effectively utilize such particulate wastes and act as a scavenger in mariculture system. In this paper, the ingestion, growth, and excretion of deposit-feeder Apostichopus japonicus were investigated in situ seasonally to evaluate its bioremediation potential of a suspension aquaculture system of filter-feeding bivalves. The results showed that A. japonicus could grow well in newly designed culture nets, with its maximum specific growth rate being 0.34% d(-1). The A. japonicus could effectively use the biodeposits generated by co-cultured bivalves, and the ingestion rate at 21.2 degrees C in summer, 19.2 degrees C in autumn, and 7.7 degrees C in winter was 0.1746, 0.0989, and 0.0050 g g(-1) d(-1), respectively. A. japonicus could promote the regeneration of nutriens in biodeposits via the excretion of considerable amount of dissolved N and P, and the excretion also showed obvious seasonal fluctuation. The extrapolation based on the in situ investigation results showed that when co-cultivated with bivalves in lantern nets, A. japonicus would ingest 4.5-159.6 kg hm(-2) d(-1) of dry biodeposits and excrete 1,382.5-3,678.1 mmol hm(-2) d(-1) of NH4(+)-N and 74.6-335.7 mmol hm(-2) d(-1) of PO4(3-)-P, indicating that the deposit-feeding A. japonicus had a great bioremediation capability in suspension aquaculture systems. The integrated model of deposit-feeding A. japonicus and filter-feeding bivalve could not only benefit the economy, but also sustain the environment.

[Phosphate adsorption characteristics onto surface sediments from aquaculture area in Sungo bay].

Phosphate adsorption characteristics onto surface sediments from aquaculture area in Sungo bay were studied in laboratory simulating condition, and phosphate adsorption-desorption equilibrium mass concentration was also analyzed. The results showed that the process of phosphate adsorption onto sediments mainly occurred within 0.5 h, and attended to dynamic equilibrium after 6 h. Adsorption kinetics were fitted to modified Elovich model which can be expressed by Q = 85.536 + 35.512 lnt (R2 = 0.9602). Under low initial phosphate concentration condition, the adsorption isotherm curves were fitted to linear equation Q = 265.04c(e) - 7.46 (R2 = 0.965), while under high initial phosphate concentration condition, the adsorption isotherm curves were fitted to Langmuir equation (R2 = 0.989). The native adsorbed phosphorus was 7.46 microg/g and the maximum adsorption capacity was 769.23 microg/g. The phosphate adsorption-desorption equilibrium mass concentration was 0.028 mg/L, which indicated that the sediments played the source role in most time in this area based on the phosphate concentration in water body.

[Forms and bioavailability of phosphorus in surface sediments from Sungo Bay].

UNLABELLED: Forms and bioavailability of phosphorus in the sediments of eight sampling sites from Sungo Bay were analyzed by means of sequential extraction method (SEDEX). RESULTS: showed that: (1) The main form of total phosphorus (TP) in sediments was inorganic phosphorus (IP), which accounted for 73.33% and organic phosphorus (OP) was only the minor part. (2) Among different forms of inorganic phosphorus, calcium phosphorus (Ca-P) was the dominant forms, accounted for 45.22% of total phosphorus while organic phosphorus, adsorbed-phosphorus (Ads-P), iron-phosphorus (Fe-P) and detritus-phosphorus (Detr-P) was 26.67%, 9.92%, 4.74% and 13.46% respectively. (3) The correlation analysis among different phosphorus forms suggested that the concentrations and distribution of total phosphorus were mainly controlled by organic phosphorus (p < 0.05), while inorganic phosphorus was affected by calcium-phosphorus (p < 0.01). (4) Bioavailable phosphorus in sediments ranged from 358.05 microg/g to 448.39 microg/g and occupied 86.54% of the total phosphorus pool.