Discovery of a novel dipeptidyl boronic acid proteasome inhibitor for the treatment of multiple myeloma and triple-negative breast cancer.

A series of novel dipeptidyl boronic acid compounds were designed, synthesized and biologically investigated for the inhibition of the ß5 subunit of 20S proteasome and several compounds showed high activities with IC50 values of less than 10 nM. Some of these compounds potently inhibited the multiple myeloma (MM) cancer cell lines with IC50 values of less than 10 nM. It was reported that the inhibition of both ß2 and ß5 subunits strongly increased the cytotoxicity of proteasome inhibitors in solid tumor cells, so some of the compounds were evaluated for the inhibition of the ß2 subunit and the solid tumor triple-negative breast cancer cell line MDA-MB-231. The results showed that three compounds were active for both the ß2 subunit and the triple-negative breast cancer cell line MDA-MB-231. The in vivo pharmacokinetic results showed that compound 8t had good biological parameters for both ig and iv administrations. An in vivo pharmacodynamic experiment showed that compound 8t inhibited the ß5 subunit in whole blood more greatly than the marketed MLN9708 with the same dose at different time periods. A pathological analysis indicated that the injection of compound 8t in the tumor of a triple-negative breast cancer xenograft mice model led to tumor cell necrosis, nucleus condensation, deep staining, cell fragmentation, dissolution and neutrophil infiltration compared with the control group. The data in hand showed that compound 8t might be an effective candidate for the treatment of both MM and triple-negative breast cancer.

Preparation and biological evaluation of soluble tetrapeptide epoxyketone proteasome inhibitors.

A series of novel tetrapeptidyl epoxyketone inhibitors of 20S proteasome was designed and synthesized. To fully understand the SAR, various groups at R1, R2, R3, R4 and R5 positions, including aromatic and aliphatic substituents were designed, synthesized and biologically assayed. Based on the enzymatic results, seven compounds were selected to evaluate their cellular activities and soluble compound 36 showed strong potency against human multiple myeloma (MM) cell lines. Microsomal stability results indicated that compound 36 was more stable in mice, rat and human microsomes than marketed carfilzomib. The in vivo activities of this compound were evaluated with the xenograft mice models of MM cell lines ARH77 and RPMI-8226 with luciferase expression and the T/C value of the two models were 49.5% and 37.6%, respectively. To evaluate the potential cardiovascular toxicity, inhibition of hERG ion channel in HEK293 cells by compound 36 and carfilzomib was carried out. The results indicated that 36 had no binding affinity for the hERG ion channel while carfilzomib could bind it with IC50 of 92.1 µM.

Design, synthesis, in vitro and in vivo evaluation, and structure-activity relationship (SAR) discussion of novel dipeptidyl boronic acid proteasome inhibitors as orally available anti-cancer agents for the treatment of multiple myeloma and mechanism studies.

A series of novel dipeptidyl boronic acid inhibitors of 20S proteasome were designed and synthesized. Aliphatic groups at R1 position were designed for the first time to fully understand the SAR (structure-activity relationship). Among the screened compounds, novel inhibitor 5c inhibited the CT-L (chymotrypsin-like) activity with IC50 of 8.21 nM and the MM (multiple myeloma) cells RPMI8226, U266B and ARH77 proliferations with the IC50 of 8.99, 6.75 and 9.10 nM, respectively, which showed similar in vitro activities compared with the compound MLN2238 (biologically active form of marketed MLN9708). To investigate the oral availability, compound 5c was esterified to its prodrug 6a with the enzymatic IC50 of 6.74 nM and RPMI8226, U266B and ARH77 cell proliferations IC50 of 2.59, 4.32 and 3.68 nM, respectively. Furthermore, prodrug 6a exhibited good pharmacokinetic properties with oral bioavailability of 24.9%, similar with MLN9708 (27.8%). Moreover, compound 6a showed good microsomal stabilities and displayed stronger in vivo anticancer efficacy than MLN9708 in the human ARH77 xenograft mouse model. Finally, cell cycle results showed that compound 6a had a significant inhibitory effect on CT-L and inhibited cell cycle progression at the G2M stage.

Design, synthesis and docking studies of novel dipeptidyl boronic acid proteasome inhibitors constructed from αα- and αß-amino acids.

A series of novel dipeptidyl boronic acid proteasome inhibitors constructed from αα- and αß-amino acids were designed and synthesized. Their structures were elucidated by (1)H NMR, (13)C NMR, LC-MS and HRMS. These compounds were evaluated for their ß5 subunit inhibitory activities of human proteasome. The results showed that dipeptidyl boronic acid inhibitors composed of αα-amino acids were as active as bortezomib. Interestingly, the activities of those derived from αß-amino acids lost completely. Of all the inhibitors, compound 22 (IC50=4.82 nM) was the most potent for the inhibition of proteasome activity. Compound 22 was also the most active against three MM cell lines with IC50 values less than 5 nM in inhibiting cell growth assays. Molecular docking studies displayed that 22 fitted very well in the ß5 subunit active pocket of proteasome.

3D-QSAR-aided design, synthesis, in vitro and in vivo evaluation of dipeptidyl boronic acid proteasome inhibitors and mechanism studies.

Proteasome had been clinically validated as an effective target for the treatment of cancers. Up to now, many structurally diverse proteasome inhibitors were discovered. And two of them were launched to treat multiple myeloma (MM) and mantle cell lymphoma (MCL). Based on our previous biological results of dipeptidyl boronic acid proteasome inhibitors, robust 3D-QSAR models were developed and structure-activity relationship (SAR) was summarized. Several structurally novel compounds were designed based on the theoretical models and finally synthesized. Biological results showed that compound 12e was as active as the standard bortezomib in enzymatic and cellular activities. In vivo pharmacokinetic profiles suggested compound 12e showed a long half-life, which indicated that it could be administered intravenously. Cell cycle analysis indicated that compound 12e inhibited cell cycle progression at the G2M stage.

Identification of candidate biomarkers and prognostic analysis of recurrence in colorectal cancer.

Colorectal cancer (CRC) is one of the most common digestive tract malignant tumors, which has a high mortality rate especially for patients with CRC recurrence. However, the pathological mechanism of recurrence of CRC is unclear. In this study, we integrated multiple cohort datasets and databases to clarify and verify potential key candidate biomarkers and signal transduction pathways in recurrence of CRC. As results, 628 DEGs were identified from GSE33113 and GSE2630 datasets and their function and pathway were analyzed. 14 hub genes related to CRC recurrence were screened from and their influence on survival were analyzed. Two key genes (IL1B and DDAH1) regarded as prognostic factors were further screened. Relapse-free survival results indicated the interaction between IL1B and DDAH1 genes and B cells was the most obvious and correlated with survival, with statistical significance (P< 0.05). Specially, cox regression analysis suggested that patients with T1 and N0 stages had a higher risk of recurrence than patients with T2 and N1. This work would provide potential value for prognosis, and would promote molecular targeting therapy for CRC recurrence.

In vitro and in vivo efficacy of the novel oral proteasome inhibitor NNU546 in multiple myeloma.

Proteasome inhibition demonstrates highly effective impact on multiple myeloma (MM) treatment. Here, we aimed to examine anti-tumor efficiency and underlying mechanisms of a novel well tolerated orally applicable proteasome inhibitor NNU546 and its hydrolyzed pharmacologically active form NNU219. NNU219 showed more selective inhibition to proteasome catalytic subunits and less off-target effect than bortezomib ex vivo. Moreover, intravenous and oral administration of either NNU219 or NNU546 led to more sustained pharmacodynamic inhibitions of proteasome activities compared with bortezomib. Importantly, NNU219 exhibited potential anti-MM activity in both MM cell lines and primary samples in vitro. The anti-MM activity of NNU219 was associated with induction of G2/M-phase arrest and apoptosis via activation of the caspase cascade and endoplasmic reticulum stress response. Significant growth-inhibitory effects of NNU219 and NNU546 were observed in 3 different human MM xenograft mouse models. Furthermore, such observation was even found in the presence of a bone marrow microenvironment. Taken together, these findings provided the basis for clinical trial of NNU546 to determine its potential as a candidate for MM treatment.

Design, synthesis, SAR discussion, in vitro and in vivo evaluation of novel selective EGFR modulator to inhibit L858R/T790M double mutants.

Based upon the modeling binding mode of marketed AZD9291 with T790M, a series of 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline derivatives were designed and synthesized with the purpose to overcome the drug resistance resulted from T790M/L858R double mutations. The most potent compound 8 showed excellent enzyme inhibitory activities and selectivity with sub nanomolar IC50 values for both the single L858R and double T790M/L858R mutant EGFRs, and was more than 8-fold selective for wild type EGFR. Compound 8 exhibited good microsomes stabilities and pharmacokinetic properties and lower binding affinity to hERG ion channel than AZD9291 and displayed strong antiproliferative activity against the H1975 non-small cell lung cancer (NSCLC) cells bearing T790M/L858R and in vivo anticancer efficacy in a human NSCLC (H1975) xenograft mouse model.